PREAMBLE (NOT PART OF THE STANDARD)

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END OF PREAMBLE (NOT PART OF THE STANDARD)

EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM

EN 1991-2

September 2003

ICS 91.010.30; 93.040

Supersedes ENV 1991-3:1995
Incorporating corrigendum February 2010

English version

Eurocode 1: Actions on structures - Part 2: Traffic loads on bridges

Eurocode 1: Actions sur les structures - Partie 2: Actions sur les ponts, dues au trafic Eurocode 1: Einwirkungen auf Tragwerke - Teil 2: Verkehrslasten auf Brücken

This European Standard was approved by CEN on 28 November 2002.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom.

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© 2003 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members.

Ref. No. EN 1991-2:2003 E

1

Contents

FOREWORD 7
  BACKGROUND OF THE EUROCODE PROGRAMME 7
  STATUS AND FIELD OF APPLICATION OF EUROCODES 8
  NATIONAL STANDARDS IMPLEMENTING EUROCODES 9
  LINKS BETWEEN EUROCODES AND HARMONISED TECHNICAL SPECIFICATIONS (ENS AND ETAS) FOR PRODUCTS 9
  ADDITIONAL INFORMATION SPECIFIC TO EN 1991-2 9
  NATIONAL ANNEX FOR EN 1991-2 11
SECTION 1 GENERAL 15
  1.1 SCOPE 15
  1.2 NORMATIVE REFERENCES 16
  1.3 DISTINCTION BETWEEN PRINCIPLES AND APPLICATION RULES 16
  1.4 TERMS AND DEFINITIONS 17
    1.4.1 Harmonised terms and common definitions 17
    1.4.2 Terms and definitions specifically for road bridges 19
    1.4.3 Terms and definitions specifically for railway bridges 20
  1.5 SYMBOLS 21
    1.5.1 Common symbols 21
    1.5.2 Symbols specifically for sections 4 and 5 21
    1.5.3 Symbols specifically for section 6 23
SECTION 2 CLASSIFICATION OF ACTIONS 27
  2.1 GENERAL 27
  2.2 VARIABLE ACTIONS 27
  2.3 ACTIONS FOR ACCIDENTAL DESIGN SITUATIONS 28
SECTION 3 DESIGN SITUATIONS 30
SECTION 4 ROAD TRAFFIC ACTIONS AND OTHER ACTIONS SPECIFICALLY FOR ROAD BRIDGES 31
  4.1 FIELD OF APPLICATION 31
  4.2 REPRESENTATION OF ACTIONS 31
    4.2.1 Models of road traffic loads 31
    4.2.2 Loading classes 32
    4.2.3 Divisions of the carriageway into notional lanes 32
    4.2.4 Location and numbering of the lanes for design 33
    4.2.5 Application of the load models on the individual lanes 34
  4.3 VERTICAL LOADS - CHARACTERISTIC VALUES 35
    4.3.1 General and associated design situations 35
    4.3.2 Load Model 1 35
    4.3.3 Load Model 2 38
    4.3.4 Load Model 3 (special vehicles) 39
    4.3.5 Load Model 4 (crowd loading) 39
    4.3.6 Dispersal of concentrated loads 40
  4.4 HORIZONTAL FORCES - CHARACTERISTIC VALUES 41
    4.4.1 Braking and acceleration forces 41 2
    4.4.2 Centrifugal and other transverse forces 42
  4.5 GROUPS OF TRAFFIC LOADS ON ROAD BRIDGES 42
    4.5.1 Characteristic values of the multi-component action 42
    4.5.2 Other representative values of the multi-component action 44
    4.5.3 Groups o f loads in transient design situations 44
  4.6 FATIGUE LOAD MODELS 45
    4.6.1 General 45
    4.6.2 Fatigue Load Model 1 (similar to LM1) 48
    4.6.3 Fatigue Load Model 2 (set of “frequent” lorries) 48
    4.6.4 Fatigue Load Model 3 (single vehicle model) 49
    4.6.5 Fatigue Load Model 4 (set of “standard” lorries) 50
    4.6.6 Fatigue Load Model 5 (based on recorded road traffic data) 53
  4.7 ACTIONS FOR ACCIDENTAL DESIGN SITUATIONS 53
    4.7.1 General 53
    4.7.2 Collision forces from vehicles under the bridge 53
      4.7.2.1 Collision forces on piers and other supporting members 53
      4.7.2.2 Collision forces on decks 53
    4.7.3 Actions from vehicles on the bridge 54
      4.7.3.1 Vehicle on footways and cycle tracks on road bridges 54
      4.7.3.2 Collision forces on kerbs 55
      4.7.3.3 Collision forces on vehicle restraint systems 55
      4.7.3.4 Collision forces on structural members 56
  4.8 ACTIONS ON PEDESTRIAN PARAPETS 56
  4.9 LOAD MODELS FOR ABUTMENTS AND WALLS ADJACENT TO BRIDGES 57
    4.9.1 Vertical loads 57
    4.9.2 Horizontal force 57
SECTION 5 ACTIONS ON FOOTWAYS, CYCLE TRACKS AND FOOTBRIDGES 59
  5.1 FIELD OF APPLICATION 59
  5.2 REPRESENTATION OF ACTIONS 59
    5.2.1 Models of the loads 59
    5.2.2 Loading classes 60
    5.2.3 Application of the load models 60
  5.3 STATIC MODELS FOR VERTICAL LOADS - CHARACTERISTIC VALUES 60
    5.3.1 General 60
    5.3.2 Load Models 61
      5.3.2.1 Uniformly distributed load 61
      5.3.2.2 Concentrated load 61
      5.3.2.3 Service vehicle 62
  5.4 STATIC MODEL FOR HORIZONTAL FORCES - CHARACTERISTIC VALUES 62
  5.5 GROUPS OF TRAFFIC LOADS ON FOOTBRIDGES 62
  5.6 ACTIONS FOR ACCIDENTAL DESIGN SITUATIONS FOR FOOTBRIDGES 63
    5.6.1 General 63
    5.6.2 Collision forces from road vehicles under the bridge 63
      5.6.2.1 Collision forces on piers 63
      5.6.2.2 Collision forces on decks 64
    5.6.3 Accidental presence of vehicles on the bridge 64
  5.7 DYNAMIC MODELS OF PEDESTRIAN LOADS 65
  5.8 ACTIONS ON PARAPETS 65 3
  5.9 LOAD MODEL FOR ABUTMENTS AND WALLS ADJACENT TO BRIDGES 65
SECTION 6 RAIL TRAFFIC ACTIONS AND OTHER ACTIONS SPECIFICALLY FOR RAILWAY BRIDGES 66
  6.1 FIELD OF APPLICATION 66
  6.2 REPRESENTATION OF ACTIONS - NATURE OF RAIL TRAFFIC LOADS 67
  6.3 VERTICAL LOADS - CHARACTERISTIC VALUES (STATIC EFFECTS) AND ECCENTRICITY AND DISTRIBUTION OF LOADING 67
    6.3.1 General 67
    6.3.2 Load Model 71 67
    6.3.3 Load Models SW/0 and SW/2 68
    6.3.4 Load Model “unloaded train” 69
    6.3.5 Eccentricity of vertical loads (Load Models 71 and SW/0) 69
    6.3.6 Distribution of axle loads by the rails, sleepers and ballast 70
      6.3.6.1 Longitudinal distribution of a point force or wheel load by the rail 70
      6.3.6.2 Longitudinal distribution of load by sleepers and ballast 71
      6.3.6.3 Transverse distribution of actions by the sleepers and ballast 71
      6.3.6.4 Equivalent, vertical loading for earthworks and earth pressure effects 73
    6.3.7 Actions for non-public footpaths 74
  6.4 DYNAMIC EFFECTS (INCLUDING RESONANCE) 74
    6.4.1 Introduction 74
    6.4.2 Factors influencing dynamic behaviour 74
    6.4.3 General design rules 75
    6.4.4 Requirement for a static or dynamic analysis 75
    6.4.5 Dynamic factor Φ(Φ2, Φ3) 78
      6.4.5.1 Field of application 78
      6.4.5.2 Definition of the dynamic factor Φ 78
      6.4.5.3 Determinant length LΦ 79
      6.4.5.4 Reduced dynamic effects 82
    6.4.6 Requirements for a dynamic analysis 83
      6.4.6.1 Loading and load combinations 83
      6.4.6.2 Speeds to be considered 87
      6.4.6.3 Bridge parameters 88
      6.4.6.4 Modelling the excitation and dynamic behaviour of the structure 89
      6.4.6.5 Verifications of the limit states 91
      6.4.6.6 Additional verification for fatigue where dynamic analysis is required 92
  6.5 HORIZONTAL FORCES - CHARACTERISTIC VALUES 93
    6.5.1 Centrifugal forces 93
    6.5.2 Nosing force 97
    6.5.3 Actions due to traction and braking 97
    6.5.4 Combined response of structure and track to variable actions 98
      6.5.4.1 General principles 98
      6.5.4.2 Parameters affecting the combined response of the structure and track 99
      6.5.4.3 Actions to be considered 101
      6.5.4.4 Modelling and calculation of the combined track/structure system 102
      6.5.4.5 Design criteria 104
      6.5.4.6 Calculation methods 105
  6.6 AERODYNAMIC ACTIONS FROM PASSING TRAINS 108
    6.6.1 General 108
    6.6.2 Simple vertical surfaces parallel to the track (e.g. noise barriers) 109 4
    6.6.3 Simple horizontal surfaces above the track (e.g. overhead protective structures) 110
    6.6.4 Simple horizontal surfaces adjacent to the track (e.g. platform canopies with no vertical wall) 111
    6.6.5 Multiple-surface structures alongside the track with vertical and horizontal or inclined surfaces (e.g. bent noise barriers, platform canopies with vertical walls etc.) 112
    6.6.6 Surfaces enclosing the structure gauge of the tracks over a limited length (up to 20 m) (horizontal surface above the tracks and at least one vertical wall, e.g. scaffolding, temporary constructions) 112
  6.7 DERAILMENT AND OTHER ACTIONS FOR RAILWAY BRIDGES 113
    6.7.1 Derailment actions from rail traffic on a railway bridge 113
    6.7.2 Derailment under or adjacent to a structure and other actions for Accidental Design Situations 115
    6.7.3 Other actions 115
  6.8 APPLICATION OF TRAFFIC LOADS ON RAILWAY BRIDGES 115
    6.8.1 General 115
    6.8.2 Groups of Loads - Characteristic values of the rnulticomponent action 118
    6.8.3 Groups of Loads - Other representative values of the multicomponent actions 120
      6.8.3.1 Frequent values of the multicomponent actions 120
      6.8.3.2 Quasi-permanent values of the rnulticomponerit actions 121
    6.8.4 Traffic loads in Transient Design Situations 121
  6.9 TRAFFIC LOADS FOR FATIGUE 121
ANNEX A (INFORMATIVE) MODELS OF SPECIAL VEHICLES FOR ROAD BRIDGES 123
  A.1 SCOPE AND FIELD OF APPLICATION 123
  A.2 BASIC MODELS OF SPECIAL VEHICLES 123
  A.3 APPLICATION OF SPECIAL VEHICLE LOAD MODELS ON THE CARRIAGEWAY 125
ANNEX B (INFORMATIVE) FATIGUE LIFE ASSESSMENT FOR ROAD BRIDGES ASSESSMENT METHOD BASED ON RECORDED TRAFFIC 128
ANNEX C (NORMATIVE) DYNAMIC FACTORS 1 + φ FOR REAL TRAINS 132
ANNEX D (NORMATIVE) BASIS FOR THE FATIGUE ASSESSMENT OF RAILWAY STRUCTURES 134
  D.1 ASSUMPTIONS FOR FATIGUE ACTIONS 134
  D.2 GENERAL DESIGN METHOD 135
  D.3 TRAIN TYPES FOR FATIGUE 135
ANNEX E (INFORMATIVE) LIMITS OF VALIDITY OF LOAD MODEL HSLM AND THE SELECTION OF THE CRITICAL UNIVERSAL TRAIN FROM HSLM-A 141
  E.1 LIMITS OF VALIDITY OF LOAD MODEL HSLM 141
  E.2 SELECTION OF A UNIVERSAL TRAIN FROM HSLM-A 142
ANNEX F (INFORMATIVE) CRITERIA TO BE SATISFIED IF A DYNAMIC ANALYSIS IS NOT REQUIRED 150 5
ANNEX G (INFORMATIVE) METHOD FOR DETERMINING THE COMBINED RESPONSE OF A STRUCTURE AND TRACK TO VARIABLE ACTIONS 155
  G.1 INTRODUCTION 155
  G.2 LIMITS OF VALIDITY OF CALCULATION METHOD 155
  G.3 STRUCTURES CONSISTING OF A SINGLE BRIDGE DECK 156
  G.4 STRUCTURES CONSISTING OF A SUCCESSION OF DECKS 162
ANNEX H (INFORMATIVE) LOAD MODELS FOR RAIL TRAFFIC LOADS IN TRANSIENT DESIGN SITUATIONS 164
6

Foreword

This document (EN 1991-2:2003) has been prepared by Technical Committee CEN/TC 250 “Structural Eurocodes”, the secretariat of which is held by BSI.

This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by March 2004, and conflicting national standards shall be withdrawn at the latest by Image March 2010 Image.

This document supersedes ENV 1991-3:1995.

CEN/TC 250 is responsible for all Structural Eurocodes.

Image According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Image

Background of the Eurocode Programme

In 1975, the Commission of the European Community decided on an action programme in the field of construction, based on article 95 of the Treaty. The objective of the programme was the elimination of technical obstacles to trade and the harmonisation of technical specifications.

Within this action programme, the Commission took the initiative to establish a set of harmonised technical rules for the design of construction works which, in a first stage, would serve as an alternative to the national rules in force in the Member States and, ultimately, would replace them.

For fifteen years, the Commission, with the help of a Steering Committee with Representatives of Member States, conducted the development of the Eurocodes programme, which led to the first generation of European codes in the 1980s.

In 1989, the Commission and the Member States of the EU and EFTA decided, on the basis of an agreement1 between the Commission and CEN, to transfer the preparation and the publication of the Eurocodes to CEN through a series of Mandates, in order to provide them with a future status of European Standard (EN). This links de facto the Eurocodes with the provisions of all the Council’s Directives and/or Commission’s Decisions dealing with European standards (e.g. the Council Directive 89/106/EEC on construction products - CPD - and Council Directives 93/37/EEC, 92/50/EEC and 89/440/EEC on public works and services and equivalent EFTA Directives initiated in pursuit of setting up the internal market).

1 Agreement between the Commission of the European Communities and the European Committee for Standardisation (CEN) concerning the work on EUROCODES for the design of building and civil engineering works (BC/CEN/03/89).

7

The Structural Eurocode programme comprises the following standards generally consisting of a number of Parts:

EN 1990 Eurocode: Basis of Structural Design
EN 1991 Eurocode 1; Actions on structures
EN 1992 Eurocode 2; Design of concrete structures
EN 1993 Eurocode 3; Design of steel structures
EN 1994 Eurocode 4; Design of composite steel and concrete structures
EN 1995 Eurocode 5; Design of timber structures
EN 1996 Eurocode 6; Design of masonry structures
EN 1997 Eurocode 7; Geotechnical design
EN 1998 Eurocode 8; Design of structures for earthquake resistance
EN 1999 Eurocode 9: Design of aluminium structures

Eurocode standards recognise the responsibility of regulatory authorities in each Member State and have safeguarded their right to determine values related to regulatory safety matters at national level where these continue to vary from State to State.

Status and field of application of Eurocodes

The Member States of the EU and EFTA recognise that Eurocodes serve as reference documents for the following purposes :

The Eurocodes, as far as they concern the construction works themselves, have a direct relationship with the Interpretative Documents2 referred to in Article 12 of the CPD, although they are of a different nature from harmonised product standards3. Therefore, technical aspects arising from the Eurocodes work need to be adequately considered by CEN Technical Committees and/or EOTA Working Groups working on product standards with a view to achieving a full compatibility of these technical specifications with the Eurocodes.

2 According to Art. 3.3 of the CPD, the essential requirements (ERs) shall be given concrete form in interpretative documents for the creation of the necessary links between the essential requirements and the mandates for harmonised ENs and ETAGs/ETAs.

3 According to Art. 12 of the CPD the interpretative documents shall :

  1. give concrete form to the essential requirements by harmonising the terminology and the technical bases and indicating classes or levels for each requirement where necessary ;
  2. indicate methods of correlating these classes or levels of requirement with the technical specifications, e.g. methods of calculation and of proof, technical rules for project design, etc. ;
  3. serve as a reference for the establishment of harmonised standards and guidelines for European technical approvals.

The Eurocodes, de facio, play a similar role in the field of the ER 1 and a part of ER 2.

8

The Eurocode standards provide common structural design rules for everyday use for the design of whole structures and component products of both a traditional and an innovative nature. Unusual forms of construction or design conditions are not specifically covered and additional expert consideration will be required by the designer in such cases.

National Standards implementing Eurocodes

The National Standards implementing Eurocodes will comprise the full text of the Eurocode (including any annexes), as published by CEN, which may be preceded by a National title page and National foreword, and may be followed by a National Annex.

The National Annex may only contain information on those parameters which are left open in the Eurocode for national choice, known as Nationally Determined Parameters, to be used for the design of buildings and civil engineering works to be constructed in the country concerned, i.e. :

It may also contain

Links between Eurocodes and harmonised technical specifications (ENs and ETAs) for products

There is a need for consistency between the harmonised technical specifications for construction products and the technical rules for works4. Furthermore, all the information accompanying the CE Marking of the construction products which refer to Eurocodes should clearly mention which Nationally Determined Parameters have been taken into account.

Additional information specific to EN 1991-2

EN 1991-2 defines models of traffic loads for the design of road bridges, footbridges and railway bridges. For the design of new bridges, EN 1991-2 is intended to be used, for direct application, together with Eurocodes EN 1990 to 1999.

The bases for combinations of traffic loads with non-traffic loads are given in EN 1990, A2.

4 see Art.3.3 and Art. 12 of the CPD, as well as clauses 4.2, 4.3.1, 4.3.2 and 5.2 of ID 1 (Interpretative Document: Nr. 1).

9

Complementary rules may be specified for individual projects :

For road bridges, Load Models 1 and 2, defined in 4.3.2 and 4.3.3, and taken into account with adjustment factors α and β equal to 1, are deemed to represent the most severe traffic met or expected in practice, other than that of special vehicles requiring permits to travel, on the main routes of European countries. The traffic on other routes in these countries and in some other countries may be substantially lighter, or better controlled. However it should be noted that a great number of existing bridges do not meet the requirements of this EN 1991-2 and the associated Structural Eurocodes EN 1992 to EN 1999.

It is therefore recommended to the national authorities that values of the adjustment factors α and β be chosen for road bridge design corresponding possibly to several classes of routes on which the bridges are located, but remain as few and simple as possible, based on consideration of the national traffic regulations and the efficiency of the associated control.

For railway bridges, Load Model 71 (together with Load Model SW/0 for continuous bridges), defined in 6.3.2, represent the static effect of standard rail traffic operating over the standard-gauge or wide-gauge European mainline-network. Load Model SW/2, defined in 6.3.3, represents the static effect of heavy rail traffic. The lines, or sections of lines, over which such loads shall be taken into account are defined in the National Annex (see below) or for the individual project.

Provision is made for varying the specified loading to cater for variations in the type, volume and maximum weight of rail traffic on different railways, as well as for different qualities of track. The characteristic values given for Load Models 71 and SW/0 may be multiplied by a factor α for lines carrying rail traffic which is heavier or lighter than the standard.

In addition two other load models are given for railway bridges :

Guidance is also given on aerodynamic actions on structures adjacent to railway tracks as a result of passing trains and on other actions from railway infrastructure.

Bridges are essentially public works, for which :

10

Public authorities may also have responsibilities for the issue of regulations on authorised traffic (especially on vehicle loads) and for delivery and control dispensations when relevant, e.g. for special vehicles.

EN 1991-2 is therefore intended for use by :

Image Where a Table or a Figure Image are part of a NOTE, the Table or the Figure number is followed by (n) (e.g. Table 4.5(n)).

National Annex for EN 1991-2

This Standard gives alternative procedures, values and recommendations for classes with notes indicating where national choices have to be made. Therefore the National Standard implementing EN 1991-2 should have a National Annex containing all Nationally Determined Parameters to be used for the design of bridges to be constructed in the relevant country.

National choice is allowed in EN 1991-2 through the following clauses :

Section 1 : General
1.1(3) Complementary rules for retaining walls, buried structures and tunnels.
 
Section 2 : Classification of actions
2.2(2) NOTE 2 Use of infrequent values of loading for road bridges
2.3(1) Definition of appropriate protection against collisions
2.3(4) Rules concerning collisions forces from various origins
 
Section 3 : Design situations
(5) Rules for bridges carrying both road and rail traffic
 
Section 4 : Road traffic actions and other actions specifically for road bridges
4.1(1) NOTE 2 Road traffic actions for loaded lengths greater than 200m
4.1(2) NOTE 1 Specific load models for bridges with limitation of vehicle weight
4.2.1(1) NOTE 2 Definition of complementary load models
4.2.1(2) Definition of models of special vehicles
4.2.3(1) Conventional height of kerbs
4.3.1(2) NOTE 2 Use of LM2
4.3.2(3) NOTES 1 & 2 Values of α factors 11
4.3.2(6) Use of simplified alternative load models
4.3.3(2) Values of β factor
4.3.3(4) NOTE 2 Selection of wheel contact surface for LM2
4.3.4(1) Definition of Load Model 3 (special vehicles)
4.4.1(2) NOTE 2 Upper limit of the braking force on road bridges
Image Text deleted Image Image Text deleted Image
4.4.1(3) Horizontal forces associated with Load Model 3
4.4.1(6) Braking force transmitted by expansion joints
4.4.2(4) Lateral forces on road bridge decks
4.5.1 – Table 4.4a Notes a and b Consideration of horizontal forces in grla
Image 4.5.2(1) NOTE 3 Image Use of infrequent values of variable actions
Image 4.6.1(2) NOTE 2 and NOTE 4 Image Use of Fatigue Load Models
4.6.1(3) NOTE 1 Definition of traffic categories
4.6.1(6) Definition of additional amplification factor (fatigue)
4.6.4(3) Adjustment of Fatigue Load Model 3
4.6.5(1) NOTE 2 Road traffic characteristics for the use of Fatigue Load Model 4
4.6.6(1) Use of Fatigue Load Model 5
4.7.2.1(1) Definition of impact force and height of impact
4.7.2.2(1) NOTE 1 Definition of collision forces on decks
4.7.3.3(1) NOTE 1 Definition of collision forces on vehicle restraint systems
4.7.3.3(1) NOTE 3 Definition of vertical force acting simultaneously with the horizontal collision force
4.7.3.3(2) Design load for the structure supporting a vehicle parapet
4.7.3.4(1) Definition of collision forces on unprotected vertical structural members
4.8(1) NOTE 2 Definition of actions on pedestrian parapets
4.8(3) Definition of design loads due to pedestrian parapets for the supporting structure
4.9.1(1) NOTE 1 Definition of load models on embankments
 
Section 5 : Actions on footways, cycle tracks and footbridges
5.2.3(2) Definition of load models for inspection gangways
5.3.2.1(1) Definition of the characteristic value of the uniformly distributed load
5.3.2.2(1) Definition of the characteristic value of the concentrated load on footbridges
5.3.2.3(1)P NOTE 1 Definition of service vehicles for footbridges
5.4(2) Characteristic value of the horizontal force on footbridges 12
5.6.1(1) Definition of specific collision forces
5.6.2.1(1) Collision forces on piers
5.6.2.2(1) Collision forces on decks
5.6.3(2) NOTE 2 Definition of a load model for accidental presence of a vehicle on a footbridge
5.7(3) Definition of dynamic models of pedestrian loads
 
Section 6 : Rail traffic actions and other actions specifically for railway bridges
6.1(2) Traffic outside the scope of EN 1991-2, alternative load models
6.1(3)P Other types of railways
6.1(7) Temporary bridges
6.3.2(3)P Values of α factor
6.3.3(4)P Choice of lines for heavy rail traffic
6.4.4 Alternative requirements for a dynamic analysis
6.4.5.2(3)P Choice of dynamic factor
6.4.5.3(1) Alternative values of determinant lengths
6.4.5.3 Table 6.2 Determinant length of cantilevers
6.4.6.1.1(6) Additional requirements for the application of HSLM
6.4.6.1.1(7) Loading and methodology for dynamic analysis
6.4.6.1.2(3) Table 6.5 Additional load cases depending upon number of tracks
6.4.6.3.1(3) Table 6.6 Values of damping
6.4.6.3.2(3) Alternative density values of materials
6.4.6.3.3(3) NOTE 1
NOTE 2
Enhanced Young’s modulus
Other material properties
6.4.6.4(4) Reduction of peak response at resonance and alternative additional damping values
6.4.6.4(5) Allowance for track defects and vehicle imperfections
6.5.1(2) Increased height of centre of gravity for centrifugal forces
6.5.3(5) Actions due to braking for loaded lengths greater than 300 m
6.5.3(9)P Alternative requirements for the application of traction and braking forces
6.5.4.1(5) Combined response of structure and track, requirements for non-ballasted track
6.5.4.3.(2) NOTES 1 & 2 Alternative requirements for temperature range
6.5.4.4(2) NOTE 1 Longitudinal shear resistance between track and bridge deck
6.5.4.5 Alternative design criteria
6.5.4.5.1(2) Minimum value of track radius
6.5.4.5.1(2) Limiting values for rail stresses
6.5.4.6 Alternative calculation methods
6.5.4.6.1(1) Alternative criteria for simplified calculation methods
6.5.4.6.1(4) Longitudinal plastic shear resistance between track and bridge deck
6.6.1(3) Aerodynamic actions, alternative values
6.7.1(2)P Derailment of rail traffic, additional requirements 13
6.7.1(8)P Derailment of rail traffic, measures for structural elements situated above the level of the rails and requirements to retain a derailed train on the structure
6.7.3(1)P Other actions
6.8.1(11)P Table 6.10 Number of tracks loaded when checking drainage and structural clearances
6.8.2(2) Table 6.11 Assessment of groups of loads
6.8.3.1(1) Frequent values of multi-component actions
6.8.3.2(1) Quasi-permanent values of multi-component actions
6.9(6) Fatigue load models, structural life
6.9(7) Fatigue load models, special traffic
Annex C(3)P Dynamic factor
Annex C(3)P Method of dynamic analysis
Annex D2(2) Partial safety factor for fatigue loading
14

Section 1 General

1.1 Scope

  1. EN 1991-2 defines imposed loads (models and representative values) associated with road traffic, pedestrian actions and rail traffic which include, when relevant, dynamic effects and centrifugal, braking and acceleration actions and actions for accidental design situations.
  2. Imposed loads defined in EN 1991-2 are intended to be used for the design of new bridges, including piers, abutments, upstand walls, wing walls and flank walls etc., and their foundations.
  3. The load models and values given in EN 1991-2 should be used for the design of retaining walls adjacent to roads and railway lines.

    NOTE For some models only, applicability conditions are defined in EN 1991-2. For the design of buried structures, retaining walls and tunnels, provisions other than those in EN 1990 to EN 1999 may be necessary. Possible complementary conditions may be defined in the National Annex or for the individual project.

  4. EN 1991-2 is intended to be used in conjunction with EN 1990 (especially A2) and EN 1991 to EN 1999.
  5. Section 1 gives definitions and symbols.
  6. Section 2 defines loading principles for road bridges, footbridges (or cycle-track bridges) and railway bridges.
  7. Section 3 is concerned with design situations and gives guidance on simultaneity of traffic load models and on combinations with non-traffic actions.
  8. Section 4 defines :
  9. Section 5 defines :
  10. Sections 4 and 5 also define loads transmitted to the structure by vehicle restraint systems and/or pedestrian parapets. 15
  11. Section 6 defines :

1.2 Normative references

This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications, are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies (including amendments).

EN 1317 Road restraint systems
Part 1 : Terminology and general criteria for test methods
Part 2 : Performance classes, impact test acceptance criteria and test methods for safety barriers
Part 6 : Pedestrian restraint systems, pedestrian parapetparpets

NOTE The Eurocodes were published as European Prestandards. The following European Standards which are published or in preparation are cited in normative clauses or in NOTES to normative clauses :

EN 1990 Eurocode : Basis of Structural Design
EN 1991-1-1 Eurocode 1 : Actions on structures : Part 1-1 : General actions - Densities, self-weight imposed loads for buildings
EN 1991-1-3 Eurocode 1 : Actions on structures : Part 1-3 : General actions - Snow loads
prEN 1991-1-4 Eurocode 1 : Actions on structures : Part 1-4 : General actions - Wind actions
prEN 1991-1-5 Eurocode 1 : Actions on structures : Part 1-5 : General actions - Thermal actions
prEN 1991-1-6 Eurocode 1 : Actions on structures : Part 1-6 : General actions - Actions during execution
prEN 1991-1-7 Eurocode 1 : Actions on structures : Part 1-7 : General actions - Accidental actions
EN 1992 Eurocode 2 : Design of concrete structures
EN 1993 Eurocode 3 : Design of steel structures
EN 1994 Eurocode 4 : Design of composite steel and concrete structures
EN 1995 Eurocode 5 : Design of timber structures
EN 1997 Eurocode 7 : Geotechnical design
EN 1998 Eurocode 8 : Design of structures for earthquake resistance
EN 1999 Eurocode 9 : Design of aluminium structures

1.3 Distinction between Principles and Application Rules

  1. Depending on the character of the individual clauses, distinction is made in EN 1991-2 between Principles and Application Rules. 16
  2. The Principles comprise :
  3. The Principles are identified by the letter P following the paragraph number.
  4. The Application Rules are generally recognised rules which comply with the Principles and satisfy their requirements.
  5. It is permissible to use alternative design rules different from the Application Rules given in EN 1991-2 for works, provided that it is shown that the alternative rules accord with the relevant Principles and are at least equivalent with regard to the structural safety, serviceability and durability which would be expected when using the Eurocodes.

    NOTE If an alternative design rule is substituted for an Application Rule, the resulting design cannot be claimed to be wholly in accordance with EN 1991-2 although the design will remain in accordance with the Principles of EN 1991-2. When EN 1991-2 is used in respect of a property listed in an annex Z of a product standard or an ETAG5, the use of an alternative design rule may not be acceptable for CE marking.

  6. In EN 1991-2, the Application Rules are identified by a number in brackets e.g. as this clause.

1.4 Terms and definitions

NOTE 1 For the purposes of this European Standard, general definitions are provided in EN 1990 and additional definitions specific to this Part are given below.

NOTE 2 Terminology for road restraint systems is derived from EN 1317-1.

1.4.1 Harmonised terms and common definitions

1.4.1.1
deck

parts of a bridge which carry the traffic loading over piers, abutments and other walls, pylons being excluded

1.4.1.2
road restraint system

general name for vehicle restraint system and pedestrian restraint system used on the road

NOTE Road restraint systems may be, according to use :

5 ETAG : European Technical Approval Guideline

17
1.4.1.3
safety barrier

road vehicle restraint system installed alongside, or on the central reserve, of a road

1.4.1.4
vehicle parapet

safety barrier installed on the edge, or near the edge, of a bridge or on a retaining wall or similar structure where there is a vertical drop and which may include additional protection and restraint for pedestrians and other road users

1.4.1.5
pedestrian restraint system

system installed to retain and to provide guidance for pedestrians

1.4.1.6
pedestrian parapet

pedestrian or “other user” restraint system along a bridge or on top of a retaining wail or similar structure and which is not intended to act as a road vehicle restraint system

1.4.1.7
pedestrian guardrail

pedestrian or “other user” restraint system along the edge of a footway or footpath intended to restrain pedestrians and other users from stepping onto or crossing a road or other area likely to be hazardous

NOTE “Other user” may include provision for equestrians, cyclists and cattle.

1.4.1.8
noise barrier

screen to reduce transmission of noise

1.4.1.9
inspection gangway

permanent access for inspection, not open for public traffic

1.4.1.10
movable inspection platform

part of a vehicle, distinct from the bridge, used for inspection

1.4.1.11
footbridge

bridge intended mainly to carry pedestrian and/or cycle-track loads, and on which neither road traffic loads, except those permitted vehicles e.g. maintenance vehicles, nor any railway load are permitted

18

1.4.2 Terms and definitions specifically for road bridges

1.4.2.1
carriageway

for application of sections 4 and 5, the part of the road surface, supported by a single structure (deck, pier, etc.), which includes all physical traffic lanes (i.e. as may be marked on the road surface), hard shoulders, hard strips and marker strips (see 4.2.3(1))

1.4.2.2
hard shoulder

surfaced strip, usually of one traffic lane width, adjacent to the outermost physical traffic lane, intended for use by vehicles in the event of difficulty or during obstruction of the physical traffic lanes

1.4.2.3
hard strip

surfaced strip, usually less than or equal to 2 m wide, located alongside a physical traffic lane, and between this traffic lane and a safety barrier or vehicle parapet

1.4.2.4
central reservation

area separating the physical traffic lanes of a dual-carriageway road. It generally includes a median strip and lateral hard strips separated from the median strip by safety barriers.

1.4.2.5
notional lane

strip of the carriageway, parallel to an edge of the carriageway, which in section 4 is deemed to carry a line of cars and/or lorries

1.4.2.6
remaining area

difference, where relevant, between the total area of the carriageway and the sum of the areas of the notional lanes (see Figure 4.1)

1.4.2.7
tandem system

assembly of two consecutive axles considered to be simultaneously loaded

1.4.2.8
abnormal load

vehicle load which may not be carried on a route without permission from the relevant authority

19

1.4.3 Terms and definitions specifically for railway bridges

1.4.3.1
tracks

tracks include rails and sleepers. They are laid on a ballast bed or are directly fastened to the decks of bridges. The tracks may be equipped with expansion joints at one end or both ends of a deck. The position of tracks and the depth of ballast may be modified during the lifetime of bridges, for the maintenance of tracks.

1.4.3.2
footpath

strip located alongside the tracks, between the tracks and the parapets

1.4.3.3
resonant speed

traffic speed at which a frequency of loading (or a multiple of) matches a natural frequency of the structure (or a multiple of)

1.4.3.4
frequent operating speed

most probable speed at the site for a particular type of Real Train (used for fatigue considerations)

1.4.3.5
maximum line speed at the site

maximum permitted speed of traffic at the site specified for the individual project (generally limited by characteristics of the infrastructure or railway operating safety requirements)

1.4.3.6
maximum permitted vehicle speed

maximum permitted speed of Real Trains due to vehicle considerations and generally independent of the infrastructure

1.4.3.7
maximum nominal speed

generally the Maximum Line Speed at the Site. Where specified for the individual project, a reduced speed may be used for checking individual Real Trains for their associated maximum permitted vehicle speed.

1.4.3.8
maximum design speed

generally 1,2 × Maximum Nominal Speed

20
1.4.3.9
maximum train commissioning speed

maximum speed used for testing a new train before the new train is brought into operational service and for special tests etc. The speed generally exceeds the Maximum Permitted Vehicle Speed and the appropriate requirements are to be specified for the individual project.

1.5 Symbols

For the purposes of this European Standard, the following symbols apply.

1.5.1 Common symbols

NOTE Symbols used in one place only are not systematically repeated below.

Latin upper case letters

L In general, loaded length

Latin upper case letters

gri Group of loads, i is a number (i = 1 to n)
r Horizontal radius of a carriageway or track centre-line, distance between wheel loads (Figure 6.3)

1.5.2 Symbols specifically for sections 4 and 5

Latin upper case letters

Qak Characteristic value of a single axle load (Load Model 2) for a road bridge (see 4.3.3)
Qflk Characteristic horizontal force on a footbridge
Qfwk Characteristic value of the concentrated load (wheel load) on a footbridge (see 5.3.2.2)
Qik Magnitude of the characterstic axle load (Load Model 1) on notional lane number i (i = 1, 2 …) of a road bridge
Qlk Magnitude of the characteristic longitudinal forces (braking and acceleration forces) on a road bridge
Qserv Load model corresponding to a service vehile for footbridges
Qtk Magnitude of the characteristic transverse or centrifugal forces on road bridges
Qtrk Tranverse braking force on road bridges
TS Tandem system for Load Model 1
UDL Uniformly distributed load for Load Model 1
21

Latin upper case letters

fh In general, natural horizontal frequency of a bridge
fv In general, natural vertical frequency of a bridge
n1 Number of notional lanes for a road bridge
qeq Equivalent uniformly distributed load for axle loads on embankments (see 4.9.1)
qfk Characteristic vertical uniformly distributed load on footways or footbridges
qik Magnitude of the characteristic vertical distributed load (Load Model 1) on notional lane number i (i = 1, 2…) of a road bridge
qrk Magnitude of the characteristic vertical distributed load on the remaining area of the carriageway (Load Model 1)
w Carriageway width for a road bridge, including hard shoulders, hard strips and marker strips (see 4.2.3(1))
w1 Width of a notional lane for a road bridge

Latin upper case letters

Δφfat Additional dynamic amplification factor for fatigue near expansion joints (see 4.6.1(6))

Latin upper case letters

αQi , αqi adjustment factors of some load models on lanes i (i = 1, 2…), defined in 4.3.2
αqr Adjustment factor of load models on the remaining area, defined in 4.3.2
βQ Adjustment factor of Load Model 2 defined in 4.3.3
φfat Dynamic amplification factor for fatigue (see annex B)
22

1.5.3 Symbols specifically for section 6

Figure 1.1 - Notation and dimensions specifically for railways

Figure 1.1 - Notation and dimensions specifically for railways

Latin upper case letters

A(L/λ) G(λ) Aggressivity (see Equations E.4 and E.5)
D Coach or vehicle length
DIC Intermediate coach length for a Regular Train with one axle per coach
Ecm Secant modulus of elasticity of normal weight concrete
FL Total longitudinal support reaction
FQk Characteristic longitudinal force per track on the fixed bearings due to deformation of the deck
FTK Longitudinal force on a fixed bearing due to the combined response of track and structure to temperature
Image Wind force compatible with rail traffic
Fli Individual longitudinal support reaction corresponding to the action i
G Self-weight (general)
H Height between (horizontal) axis of rotation of the (fixed) bearing and the upper surface of the deck (underside of ballast beneath tracks)
K Total longitudinal support stiffness
K2 Longitudinal support stiffness per track per m, 2E3 kN/m
K5 Longitudinal support stiffness per track per m, 5E3 kN/m
K20 Longitudinal support stiffness per track per m, 20E3 kN/m
L Length (general)
LT Expansion length
LTP Maximum permissible expansion length
Lf Influence length of the loaded part of curved track
Li Influence length
LΦ “determinant” length (length associated with Φ) 23
M Number of point forces in a train
N Number of regularly repeating coaches or vehicles, or
number of axles, or
number of equal point forces
P Point force
Individual axle load
Q Concentrated force or variable action (general)
QA1d Point load for derailment loading
Qh Horizontal force (general)
Qk Characteristic value of a concentrated force or a variable action (e.g. characteristic value of a vertical loading on a non-public footpath)
Qlak Characteristic value of traction force
Qlbk Characteristic value of braking force
Qr Rail traffic action (general, e.g. resultant of wind and centrifugal force)
Qsk Characteristic value of nosing force
Qtk Characteristic value of centrifugal force
Qv Vertical axle load
Qvi Wheel load
Qvk Characteristic value of vertical load (concentrated load)
ΔT Temperature variation
ΔTD Temperature variation of the deck
ΔTN Temperature variation
ΔTR Temperature variation of the rail
V Speed in km/h
Maximum Line Speed at the Site in km/h
Xi Length of sub-train consisting of i axles

Latin upper case letters

a Distance between rail supports, length of distributed loads (Load Models SW/0 and SW/2)
ag Horizontal distance to the track centre
a′g Equivalent horizontal distance to the track centre
b Length of the longitudinal distribution of a load by a sleeper and ballast
c Space between distributed loads (Load Models SW/0 and SW/2)
d Regular spacing of groups of axles
Spacing of axles within a bogie
Spacing of point forces in HSLM-B
dBA Spacing of axles within a bogie
dBS Spacing between centres of adjacent bogies
e Eccentricity of vertical loads, eccentricity of resulting action (on reference plane)
ec Distance between adjacent axles across the coupling of two individual regular trainsets
f Reduction factor for centrifugal force
fck, fck, cube Concrete compressive cylinder/ cube strength
g Acceleration due to gravity 24
h Height (general)
Height of cover including ballast from the top of the deck to the top of a sleeper
hg Vertical distance from the running surface to the underside of the structure above the track
ht Height of centrifugal force over the running surface
hw Height of wind force over the running surface
k Longitudinal plastic shear resistance of the track
k1 Train shape coefficient
k2 Multiplication factor for slipstream actions on vertical surfaces parallel to the tracks
k3 Reduction factor for slipstream actions on simple horizontal surfaces adjacent to the track
k4 Multiplication factor for slipstream actions on surfaces enclosing the tracks (horizontal actions)
k5 Multiplication factor for slipstream actions on surfaces enclosing the tracks (vertical actions)
k20 Longitudinal plastic shear resistance of track, 20kN per m of track
k40 Longitudinal plastic shear resistance of track, 40kN per m of track
k60 Longitudinal plastic shear resistance of track, 60kN per m of track
n0 First natural bending frequency of the unloaded structure
nT First natural torsional frequency of the structure
qA1d, qA2d Distributed loading for derailment loading
qfk Characteristic value of vertical loading on non-public footpath (uniformly distributed load)
qik Characteristic value of equivalent distributed aerodynamic action
qlak Characteristic value of distributed traction force
qlbk Characteristic value of distributed braking force
qtk Characteristic value of distributed centrifugal force
qv1, qv2 Vertical load (uniformly distributed load)
qvk Characteristic value of vertical load (uniformly distributed load)
r Radius of track curvature
Transverse distance between wheel loads
s Gauge
u Cant, relative vertical distance between the uppermost surface of the two rails at a particular location along the track
v Maximum Nominal Speed in m/s
Maximum Permitted Vehicle Speed in m/s
Speed in m/s
vDS Maximum Design Speed in m/s
vi Resonant speed in m/s
ydyn, ystat Maximum dynamic response and maximum corresponding static response at any particular point
25

Latin upper case letters

Θ End rotation of structure (general)
Φ(Φ23) Dynamic factor for railway Load Models 71, SW/0 and SW/2

Latin upper case letters

α Load classification factor
Coefficient for speed
Linear temperature coefficient for thermal expansion
β Ratio of the distance between the neutral axis and the surface of the deck relative to height H
δ Deformation (general)
Vertical deflection
δ0 Deflection at midspan due to permanent actions
δB Longitudinal relative displacement at the end of the deck due to traction and braking
δH Longitudinal relative displacement at the end of the deck due to deformation of the deck
δh Horizontal displacement
Horizontal displacement due to the longitudinal displacement of the foundations of the substructure
δp Horizontal displacement due to the longitudinal deformation of the substructure
δV Vertical relative displacement at the end of the deck
δφ Horizontal displacement due to longitudinal rotation of foundation
γFf Partial safety factor for fatigue loading
γMf Partial safety factor for fatigue strength
φ,φ’φ” Dynamic enhancement of static loading for Real Trains
φ’dyn Dynamic enhancement of static loading for a Real Train determined from a dynamic analysis
k Coefficient relating to the stiffness of an abutment relative to the piers
λ Damage equivalent factor for fatigue
Excitation wavelength
λC Critical wavelength of excitation
λi Principal wavelength of excitation
λv Wavelength of excitation at the Maximum Design Speed
ρ Density
σ Stress
σA, σB, Pressure on the upper surface of the deck from rail traffic actions
σM  
Δσ71 Stress range due to the Load Model 71 (and where required SW/0)
ΔσC Reference value of fatigue strength
ξ Reduction factor for the determination of the longitudinal forces in the fixed bearings of one-piece decks due to traction and braking
ξ Lower limit of percentage of critical damping (%), or damping ratio
ξTOTAL Total damping (%)
Δξ Additional damping (%)
26

Section 2 Classification of actions

2.1 General

  1. The relevant traffic actions and other specific actions on bridges should be classified in accordance with EN 1990, section 4 (4.1.1).
  2. Traffic actions on road bridges, footbridges and railway bridges consist of variable actions and actions for accidental design situations, which are represented by various models.
  3. All traffic actions should be classified as free actions within the limits specified in sections 4 to 6.
  4. Traffic actions are multi-component actions.

2.2 Variable actions

  1. For normal conditions of use (i.e. excluding any accidental situation), the traffic and pedestrian loads (dynamic amplification included where relevant) should be considered as variable actions.
  2. The various representative values are :
    Table 2.1 - Bases for the calibration of the main Load Models (fatigue excluded)
    Traffic Load Models Characteristic values Frequent values Quasi-permanent values
    Road bridges      
    LMl
    (4.3.2)
    1000 year return period (or probability of exceedance of 5% in 50 years) for traffic on the main roads in Europe factors equal to 1, see 4.3.2). 1 week return period for traffic on the main roads in Europe (α factors equal to 1, see 4.3.2). Calibration in accordance with definition given in EN 1990.
    LM2 (4.3.3) 1000 year return period (or probability of exceedance of 5% in 50 years) for traffic on the main roads in Europe (β factor equal to 1, see 4.3.3). 1 week return period for traffic on the main roads in Europe (β factor equal to 1, see 4.3.3). Not relevant
    LM3 (4.3.4) Set of nominal values. Basic values defined in annex A are derived from a synthesis based on various national regulations. Not relevant Not relevant
    LM4 (4.3.5) Nominal value deemed to represent the effects of a crowd. Defined with reference to existing national standards. Not relevant Not relevant
    Footbridges      
    Uniformly distributed load
    (5.3.2.1)
    Nominal value deemed to represent the effects of a crowd. Defined with reference to existing national standards. Equivalent static force calibrated on the basis of 2 pedestrians/m2 (in the absence of particular dynamic behaviour). It can be considered, for footbridges in urban areas, as a load of 1 week return period. Calibration in accordance with definition given in EN 1990.
    Concentrated load
    (5.3.2.2)
    Nomina] value. Defined with reference to existing national standards. Not relevant Not relevant
    Service vehicle
    (5.3.2.3)
    Nominal value. As specified or given in 5.6.3. Not relevant Not relevant

    NOTE 2 For road bridges, the National Annex may impose the use of infrequent values which are intended to correspond approximately to a mean return period of one year for traffic on the main roads in Europe. See also EN 1992-2, EN1994-2 and EN 1990, A2.

  3. For calculation of fatigue lives, separate models, associated values and, where relevant, specific requirements are given in 4.6 for road bridges, in 6.9 for railway bridges, and in the relevant annexes.

2.3 Actions for accidental design situations

  1. Road vehicles and trains may generate actions due to collision, or their accidental presence or location. These actions should be considered for the structural design where appropriate protection is not provided.

    NOTE Appropriate protection may be defined in the National Annex or for the individual project.

    28
  2. Actions for accidental design situations described in this Part of EN 1991 refer to common situations. They are represented by various load models defining design values in the form of static equivalent loads.
  3. For actions due to road vehicles under road bridges, footbridges and railway bridges during accidental design situations, see Image 4.7.2, 5.6.2 and 6.7.2 Image.
  4. Collision forces due to boats, ships or aeroplanes, for road bridges, footbridges and railway bridges (e.g. over canals and navigable water), should be defined where appropriate.

    NOTE The National Annex may define the collision forces. Recommended values for boat and ship impacts are given in EN 1991-1-7. Additional requirements may be specified for the individual project.

  5. Actions for accidental design situations due to road vehicles on road bridges and footbridges are defined in 4.7.3 and 5.6.3 respectively.
  6. Actions for accidental design situations due to trains or railway infrastructure are defined in 6.7. They are applicable where relevant to road bridges, footbridges and railway bridges.
29

Section 3 Design situations

  1. P Selected design situations shall be taken into account and critical load cases identified. For each critical load case, the design values of the effects of actions in combination shall be determined.

    NOTE For bridges for which signalling is used to limit the weight of vehicles, an accidental design situation may have to be taken into account, corresponding to the crossing of the bridge by one vehicle in breach of warnings.

  2. The various traffic loads to be taken into account as simultaneous when using groups of loads (combinations of action components) are given in the following sections ; each of which should be considered in design calculations, where relevant.
  3. P The combination rules, depending on the calculation to be undertaken, shall be in accordance with EN 1990.

    NOTE For seismic combinations for bridges and associated rules, see EN 1998-2.

  4. Specific rules for the simultaneity with other actions for road bridges, footbridges, and railway bridges are given in EN 1990, A2.
  5. For bridges intended for both road and rail traffic, the simultaneity of actions and the particular required verifications should be specified.

    NOTE The particular rules may be defined in the National Annex or for the individual project.

30

Section 4 Road traffic actions and other actions specifically for road bridges

4.1 Field of application

  1. Load models defined in this section should be used for the design of road bridges with loaded lengths less than 200 m.

    NOTE 1 200 m corresponds to the maximum length taken into account for the calibration of Load Model 1 (see 4.3.2). In general, the use of Load Model 1 is safe-sided for loaded lengths over 200 m.

    NOTE 2 Load models for loaded lengths greater than 200 m may be defined in the National Annex or for the individual project.

  2. The models and associated rules are intended to cover all normally foreseeable traffic situations (i.e. traffic conditions in either direction on any lane due to the road traffic) to be taken into account for design (see however (3) and the notes in 4.2.1).

    NOTE 1 Specific models may be defined in the National Annex or for the individual project to be used for bridges equipped with appropriate means including road signs intended to strictly limit the weight of any vehicle (e.g. for local, agricultural or private roads).

    NOTE 2 Load models for abutments and walls adjacent to bridges are defined separately (see 4.9). They derive from the road traffic models without any correction for dynamic effects. For frame bridges, loads on road embankments may also give rise to action effects in the bridge structure.

  3. The effects of loads on road construction sites (e.g. due to scrapers, lorries carrying earth, etc.) or of loads specifically for inspection and tests are not intended to be covered by the load models and should be separately specified, where relevant.

4.2 Representation of actions

4.2.1 Models of road traffic loads

  1. Loads due to the road traffic, consisting of cars, lorries and special vehicles (e.g. for industrial transport), give rise to vertical and horizontal, static and dynamic forces.

    NOTE 1 The load models defined in this section do not describe actual loads. They have been selected and calibrated so that their effects (with dynamic amplification included where indicated) represent the effects of the actual traffic in the year 2000 in European countries.

    NOTE 2 The National Annex may define complementary load models, with associated combination rules where traffic outside the scope of the load models specified in this section needs to be considered.

    NOTE 3 The dynamic amplification included in the models (fatigue excepted), although established for a medium pavement quality (see annex B) and pneumatic vehicle suspension, depends on various parameters and on the action effect under consideration. Therefore, it cannot be represented by a unique factor. In some unfavourable cases, it may reach 1,7 (local effects), but still more unfavourable values can be reached for poorer pavement quality, or if there is a risk of resonance. These cases can be avoided by appropriate quality and design measures. Therefore, an additional dynamic amplification may have to be taken into account for particular calculations (see 4.6.1.(6)) or for the individual project.

    31
  2. Where vehicles which do not comply with National regulations concerning limits of weights and, possibly, dimensions of vehicles not requiring special permits, or military loads, have to be taken into account for the design of a bridge, they should be defined.

    NOTE The National Annex may define these models. Guidance on standard models for special vehicles and their application is given in annex A. See 4.3.4.

4.2.2 Loading classes

  1. The actual loads on road bridges result from various categories of vehicles and from pedestrians.
  2. Vehicle traffic may differ between bridges depending on its composition (e.g. percentages of lorries), its density (e.g. average number of vehicles per year), its conditions (e.g. jam frequency), the extreme likely weights of vehicles and their axle loads, and, if relevant, the influence of road signs restricting carrying capacity.

    These differences should be taken into account through the use of load models suited to the location of a bridge (e.g. choice of adjustment factors α and β defined in 4.3.2 for Load Model 1 and in 4.3.3 for Load Model 2 respectively).

4.2.3 Divisions of the carriageway into notional lanes

  1. The carriageway width, w, should be measured between kerbs or between the inner limits of vehicle restraint systems, and should not include the distance between fixed vehicle restraint systems or kerbs of a central reservation nor the widths of these vehicle restraint systems.

    NOTE The National Annex may define the minimum value of the height of the kerbs to be taken into account. The recommended minimum value of this height is 100 mm.

  2. The width w1 of notional lanes on a carriageway and the greatest possible whole (integer) number n1 of such lanes on this carriageway are defined in Table 4.1. 32
    Table 4.1 - Number and width of notional lanes
    Carriageway width w Number of notional lanes Width of a notional lane wl Width of the remaining area
    w < 5,4 m n1 = 1 3 m w – 3 m
    5,4 m ≤ w < 6 m n1 = 2 Image 0
    6 m ≤ w Image 3 m w – 3 × n1
    NOTE For example, for a carriageway width equal to 11 m, Image, and the width of the remaining area is 11 – 3×3 = 2m.
  3. For variable carriageway widths, the number of notional lanes should be defined in accordance with the principles used for Table 4.1.

    NOTE For example, the number of notional lanes will be :

  4. Where the carriageway on a bridge deck is physically divided into two parts separated by a central reservation, then :
    1. each part, including all hard shoulders or strips, should be separately divided into notional lanes if the parts are separated by a permanent road restraint system ;
    2. the whole carriageway, central reservation included, should be divided into notional lanes if the parts are separated by a temporary road restraint system.

    NOTE The rules given in 4.2.3(4) may be adjusted for the individual project, allowing for envisaged future modifications of the traffic lanes on the deck, e.g. for repair.

4.2.4 Location and numbering of the lanes for design

The location and numbering of the lanes should be determined in accordance with the following rules :

  1. The locations of notional lanes should not be necessarily related to their numbering.
  2. For each individual verification (e.g. for a verification of the ultimate limit state of resistance of a cross-section to bending), the number of lanes to be taken into account as loaded, their location on the carriageway and their numbering should be so chosen that the effects from the load models are the most adverse.
  3. For fatigue representative values and models, the location and the numbering of the lanes should be selected depending on the traffic to be expected in normal conditions. 33
  4. The lane giving the most unfavourable effect is numbered Lane Number 1, the lane giving the second most unfavourable effect is numbered Lane Number 2, etc. (see Figure 4.1).

    Figure 4.1 - Example of the Lane Numbering in the most general case

    Figure 4.1 - Example of the Lane Numbering in the most general case

  5. Where the carriageway consists of two separate parts on the same deck, only one numbering should be used for the whole carriageway.

    NOTE Hence, even if the carriageway is divided into two separate parts, there is only one Lane Number 1, which can Image be considered alternatively Image on the two parts.

  6. Where the carriageway consists of two separate parts on two independent decks, each part should be considered as a carriageway. Separate numbering should then be used for the design of each deck. If the two decks are supported by the same piers and/or abutments, there should be one numbering for the two parts together for the design of the piers and/or the abutments.

4.2.5 Application of the load models on the individual lanes

  1. For each individual verification, the load models, on each notional lane, should be applied on such a length and so longitudinally located that the most adverse effect is obtained, as far as this is compatible with the conditions of application defined below for each particular model.
  2. On the remaining area, the associated load model should be applied on such lengths and widths in order to obtain the most adverse effect, as far as this is compatible with particular conditions specified in 4.3.
  3. When relevant, the various load models should be combined together (see 4.5) and with models for pedestrian or cycle loads.
34

4.3 Vertical loads - Characteristic values

4.3.1 General and associated design situations

  1. Characteristic loads are intended for the determination of road traffic effects associated with ultimate limit state verifications and with particular serviceability verifications (see EN 1990 to EN 1999).
  2. The load models for vertical loads represent the following traffic effects :
    1. Load Model 1 (LMl) : Concentrated and uniformly distributed loads, which cover most of the effects of the traffic of lorries and cars. This model should be used for general and local verifications.
    2. Load Model 2 (LM2) : A single axle load applied on specific tyre contact areas which covers the dynamic effects of the normal traffic on short structural members.

      NOTE 1 As an order of magnitude, LM2 can be predominant in the range of loaded lengths up to 3m to 7m.

      NOTE 2 The use of LM2 may be further defined in the National Annex.

    3. Load Model 3 (LM3) : A set of assemblies of axle loads representing special vehicles (e.g. for industrial transport) which can travel on routes permitted for abnormal loads. It is intended for general and local verifications.
    4. Load Model 4 (LM4) : A crowd loading, intended only for general verifications.

      NOTE This crowd loading is particularly relevant for bridges located in or near towns if its effects are not covered by Load Model 1.

  3. Load Models 1, 2 and 3, where relevant, should be taken into account for any type of design situation (e.g. for transient situations during repair works).
  4. Load Model 4 should be used only for some transient design situations.

4.3.2 Load Model 1

  1. Load Model 1 consists of two partial systems :
    1. Double-axle concentrated loads (tandem system : TS each axle having the following weight:

      αQQk     (4.1)

      where :

      αQ are adjustment factors.

      • – No more than one tandem system should be taken into account per notional lane.
      • – Only complete tandem systems should be taken into account. 35
      • – For the assessment of general effects, each tandem system should be assumed to travel centrally along the axes of notional lanes (see (5) below for local verifications and Figure 4.2b).
      • – Each axle of the tandem system should be taken into account with two identical wheels, the load per wheel being therefore equal to 0,5αQQk.
      • – The contact surface of each wheel should be taken as square and of side 0,40 m (see Figure 4.2b).
    2. Uniformly distributed loads (UDL system), having the following weight per square metre of notional lane :

      αqqk     (4-2)

      where :

      αq are adjustment factors.

      The uniformly distributed loads should be applied only in the unfavourable parts of the influence surface, longitudinally and transversally.

      NOTE LM1 is intended to cover flowing, congested or traffic jam situations with a high percentage of heavy lorries. In general, when used with the basic values, it covers the effects of a special vehicle of 600 kN as defined in annex A.

  2. Load Model 1 should be applied on each notional lane and on the remaining areas. On notional lane Number i, the load magnitudes are referred to as αQi Qik and αqi qik (see Table 4.2). On the remaining areas, the load magnitude is referred to as αqr qrk.
  3. The values of adjustment factors αQi, αqi and αqr should be selected depending on the expected traffic and possibly on different classes of routes. In the absence of specification these factors should be taken equal to unity.

    NOTE 1 The values of αQi, αq and αqr factors are given in the National Annex. In all cases, for bridges without road signs restricting vehicle weights, the following minimum values are recommended :

    αQi ≥ 0,8 and     (4.3)

    for: i ≥ 2, αqi ≥ 1 ; this restriction being not applicable to αqr     (4.4)

    NOTE 2 Values of a factors may correspond, in the National Annex, to classes of traffic. When they are taken equal to I, they correspond to a traffic for which a heavy industrial international traffic is expected, representing a large part of the total traffic of heavy vehicles. For more common traffic compositions (highways or motorways), a moderate reduction of α factors applied to tandems systems and the uniformly distributed loads on Lane 1 may be applied (10 to 20%).

  4. The characteristic values of Qik and qik , dynamic amplification included, should be taken from Table 4.2. 36
    Table 4.2 - Load model 1 : characteristic values
    Location Tandem system TS UDL system
    Axle loads Qik (kN) Image qik (or qrk)(kN/m2)Image
    Lane Number 1 300 9
    Lane Number 2 200 2,5
    Lane Number 3 100 2,5
    Other lanes 0 2,5
    Remaining area (qrk) 0 2,5

    The details of Load Model 1 are illustrated in Figure 4.2a.

    Figure 4.2a - Application of load Model 1

    Figure 4.2a - Application of load Model 1

    NOTE The application of 4.2.4-(2) and 4.3.2-(1) to (4) practically consists, for this model, of choosing the locations of the numbered lanes and the locations of the tandem systems (in most cases in the same cross-section). The length and width to be loaded by UDL are those of the relevant adverse parts of the influence surfaces.

  5. For local verifications, a tandem system should be applied at the most unfavourable location. Where two tandem systems on adjacent notional lanes are taken into account, they may be brought closer, with a distance between wheel axles not below 0,50 m (see Figure 4.2b). 37

    Figure 4.2b - Application of tandem systems for local verifications

    Figure 4.2b - Application of tandem systems for local verifications

  6. Where general and local effects can be calculated separately, the general effects may be calculated by using the following simplified alternative rules :

    NOTE The National Annex may define the conditions of use of these alternative rules.

    1. the second and third tandem systems are replaced by a second tandem system with axle weight equal to :

      (200 αQ2 + 100 αQ3) kN, or     (4.5)

    2. for span lengths greater than 10 m, each tandem system are replaced in each lane by a one-axle concentrated load of weight equal to the total weight of the two axles.

    NOTE In that case, the single axle weight is :

4.3.3 Load Model 2

  1. Load Model 2 consists of a single axle load βQQak with Qak equal to 400 kN, dynamic amplification included, which should be applied at any location on the carriageway. However, when relevant, only one wheel of 200 βQ (kN) may be taken into account.
  2. The value of βQ should be specified. 38

    NOTE The National Annex may give the value of βQ . It is recommended that βQ = αQ1.

  3. In the vicinity of expansion joints, an additional dynamic amplification factor equal to the value defined in 4.6.1(6) should be applied.
  4. The contact surface of each wheel should be taken into account as a rectangle of sides 0,35 m and 0,60 m (see Figure 4.3).

    Figure 4.3 - Load Model 2

    Figure 4.3 - Load Model 2

    NOTE 1 The contact areas of Load Models 1 and 2 are different, and correspond to different tyre models, arrangements and pressure distributions. The contact areas of Load Model 2, corresponding to twin tyres, are normally relevant for orthotropic decks.

    NOTE 2 For simplicity, the National Annex may adopt the same square contact surface for the wheels of Load Models 1 and 2.

4.3.4 Load Model 3 (special vehicles)

  1. Where relevant, models of special vehicles should be defined and taken into account.

    NOTE The National Annex may define Load Model 3 and its conditions of use. Annex A gives guidance on standard models and their conditions of application.

4.3.5 Load Model 4 (crowd loading)

  1. Crowd loading, if relevant, should be represented by a Load Model consisting of a uniformly distributed load (which includes dynamic amplification) equal to 5 kN/m2.

    NOTE The application of LM4 may be defined for the individual project.

    39
  2. Load Model 4 should be applied on the relevant parts of the length and width of the road bridge deck, the central reservation being included where relevant. This loading system, intended for general verifications, should be associated only with a transient design situation.

4.3.6 Dispersal of concentrated loads

  1. The various concentrated loads to be considered for local verifications, associated with Load Models 1 and 2, should be taken as uniformly distributed on their whole contact area.
  2. The dispersal through the pavement and concrete slabs should be taken at a spread-to-depth ratio of 1 horizontally to 1 vertically down to the level of the centroid of the slab (Figure 4.4).

    NOTE In the case of dispersal through backfill or earth, see the NOTES in 4.9.1.

    Figure 4.4 - Dispersal of concentrated loads through pavement and a concrete slab

    Figure 4.4 - Dispersal of concentrated loads through pavement and a concrete slab

  3. The dispersal through the pavement and orthotropic decks should be taken at a spread-to-depth ratio of 1 horizontally to 1 vertically down to the level of the middle plane of the structural top plate (Figure 4.5).

NOTE The transverse distribution of the load among the ribs of the orthotropic deck is not considered here.

Figure 4.5 - Dispersal of concentrated loads through pavement and orthotropic decks

Figure 4.5 - Dispersal of concentrated loads through pavement and orthotropic decks

40

4.4 Horizontal forces - Characteristic values

4.4.1 Braking and acceleration forces

  1. P A braking force, Qlk, shall be taken as a longitudinal force acting at the surfacing level of the carriageway.
  2. The characteristic value of Qlk, limited to 900 kN for the total width of the bridge, should be calculated as a fraction of the total maximum vertical loads corresponding to the Load Model 1 likely to be applied on Lane Number 1, as follows :

    Qlk = 0,6αQ1(2Qlk) + 0,10αq1q1kwlL

    180αQ1 (kN) ≤ Q1k ≤ 900 (kN)     (4.6)

    where :

    L is the length of the deck or of the part of it under consideration.

    NOTE 1 For example, Q1k = 360 + 2,7L (≤ 900 kN) for a 3m wide lane and for a loaded length L>1,2 m, if α factors are equal to unity.

    NOTE 2 The upper limit (900 kN) may be adjusted in the National Annex. The value 900 kN is normally intended to cover the maximum braking force of military vehicles according to STANAG6.

  3. Horizontal forces associated with Load Model 3 should be defined where appropriate.

    NOTE The National Annex may define horizontal forces associated with Load Model 3.

  4. This force should be taken into account as located along the axis of any lane. However, if the eccentricity effects are not significant, the force may be considered to be applied only along the carriageway axis, and uniformly distributed over the loaded length.
  5. Acceleration forces should be taken into account with the same magnitude as braking forces, but in the opposite direction.

    NOTE Practically this means that Qlk may be negative as well as positive.

  6. The horizontal force transmitted by expansion joints or applied to structural members that can be loaded by only one axle should be defined.

    NOTE The National Annex may define the value for Qlk . The recommended value is :

    Qlk = 0,6αQ1Qlk     (4.6a)

6 STANAG : Military STANdardization AGreements (STANAG 2021)

41

4.4.2 Centrifugal and other transverse forces

  1. The centrifugal force Qtk should be taken as a transverse force acting at the finished carriageway level and radially to the axis of the carriageway.
  2. The characteristic value of Qtk , in which dynamic effects are included, should be taken from Table 4.3.
    Table 4.3 - Characteristic values of centrifugal forces
    Qtk = 0,2Qv (kN) if r < 200 m
    Qtk = 40Qv/ r (kN) if 200 ≤ r ≤ 1500m
    Qtk = 0 if r > 1500 m

    where :

    r is the horizontal radius of the carriageway centreline [m]
    Qv is the total maximum weight of vertical concentrated loads of the tandem systems of LMl, Image (see Table 4.2).
  3. Qtk should be assumed to act as a point load at any deck cross-section.
  4. Where relevant, lateral forces from skew braking or skidding should be taken into account. A transverse braking force, Qtrk , equal to 25% of the longitudinal braking or acceleration force Qlk, should be considered to act simultaneously with Qlk at the finished carriageway level.

NOTE The National Annex may define a minimum transverse loading. In most cases, forces resulting from wind effects and collisions on kerbs provide a sufficient transverse loading.

4.5 Groups of traffic loads on road bridges

4.5.1 Characteristic values of the multi-component action

  1. The simultaneity of the loading systems defined in 4.3.2 (Load Model 1), 4.3.3 (Load Model 2), 4.3.4 (Load Model 3), 4.3.5 (Load Model 4), 4.4 (horizontal forces) and the loads defined in section 5 for footways should be taken into account by considering the groups of loads defined in Table 4.4a. Each of these groups of loads, which are mutually exclusive, should be considered as defining a characteristic action for combination with non-traffic loads.
42
Table 4.4a - Assessment of groups of traffic loads (charactersistic values of the multi-component action)
Image CARRIAGEWAY FOOTWAYS AND CYCLE TRACKS
Load type Vertical forces Horizontal forces Vertical forces only
Reference 4.3.2 4.3.3 4.3.4 4.3.5 4.4.1 4.4.2 5.3.2-(1)
Load system LM1(TS and UDL sysems) LM2 (Single axle) LM3 (Special vehicles) LM4 (Crowd loading) Braking and acceleration forcesa Centrifugal and transverse forcea Uniformly Distributed load
Groups of Loads gr1a Characteristic values           Combination valueb
gr1b   Characterostic value          
gr2 Frequent values       Characteristic value Characteristic value  
gr3d             Characteristic valuec
gr4       Characteristic value     Characteristic value
gr5 See annex A   Characteristic value        
  Dominant component action (designated as component associated with the group)
  1. May be defined in the National Annex (for the cases mentioned).
  2. May be defined in the National Annex. The recommanded value is 3 kN/m2
  3. See 5.3.2.1-(2). One footway only should be condiderded to be loaded if the effect is more unfavourable than the effect of two loaded footways.
  4. This group is irrelevant if gr4 is considered.

Image

43

4.5.2 Other representative values of the multi-component action

  1. The frequent action should consist only of either the frequent values of LMl or the frequent value of LM2, or the frequent values of loads on footways or cycle-tracks (taking the more unfavourable), without any accompanying component, as defined in Table 4.4b.

NOTE 1 For the individual components of the traffic action, these representative values are defined in EN 1990, A2.

NOTE 2 For quasi-permanent values (generally equal to zero), see EN 1990, A2.

NOTE 3 Where the National Annex refers to infrequent values of variable actions, the same rule as in 4.5.1 may be applied by replacing all characteristic values in Table 4.4 by infrequent values defined in EN 1990, A2, without modifying the other values mentioned in the Table. But the infrequent group gr2 is practically irrelevant for road bridges.

Table 4.4b - Assessment of groups of traffic loads (frequent values of the multi-component action)
  CARRIAGEWAY FOOTWAYS AND CYCLE TRACKS
Load type Vertical forces
Reference 4.3.2 4.3.3 5.3.2(1)
Load system LM l (TS and UDL systems) LM2 (single axle) Uniformly distributed load
  grla Frequent values    
Groups of loads grlb   Frequent value  
  gr3     Frequent value a
a One footway only should be considered to be loaded if the effect is more unfavourable than the effect of two loaded footways.

4.5.3 Groups of loads in transient design situations

  1. The rules given in 4.5.1 and 4.5.2 are applicable with the following modifications given in 4.5.3(2).
  2. For verifications in transient design situations, the characteristic values associated with the tandem system should be taken equal to 0,8αQiQk, and all other characteristic frequent and quasi-permanent values and the horizontal forces are as specified for persistent design situations without any modification (i.e. they are not reduced proportionally to the weight of the tandems).

NOTE In transient design situations due to road or bridge maintenance, the traffic is commonly concentrated on smaller areas without being significantly reduced, and long lasting traffic jams are frequent. However, more reductions may be applied in cases where the heaviest lorries are diverted by appropriate measures.

44

4.6 Fatigue load models

4.6.1 General

  1. Traffic running on bridges produces a stress spectrum which may cause fatigue. The stress spectrum depends on the geometry of the vehicles, the axle loads, the vehicle spacing, the composition of the traffic and its dynamic effects.
  2. In the following, five fatigue load models of vertical forces are defined and given in 4.6.2 to 4.6.6.

    NOTE 1 Horizontal forces may have to be taken into account simultaneously with vertical forces for the individual project : for example, centrifugal forces may occasionally need to be considered together with the vertical loads.

    NOTE 2 The use of the various Fatigue Load Models is defined in EN 1992 to EN 1999 and further information is given as below :

    1. Fatigue Load Models 1, 2 and 3 are intended to be used to determine the maximum and minimum stresses resulting from the possible load arrangements on the bridge of any of these models ; in many cases, only the algebraic difference between these stresses is used in EN 1992 to EN1999.
    2. Fatigue Load Models 4 and 5 are intended to be used to determine stress range spectra resulting from the passage of lorries on the bridge.
    3. Fatigue Load Models 1 and 2 are intended to be used to check whether the fatigue life may be considered as unlimited when a constant stress amplitude fatigue limit is given. Therefore, they are appropriate for steel constructions and may be inappropriate for other materials. Fatigue Load Model 1 is generally conservative and covers multi-lane effects automatically. Fatigue Load Model 2 is more accurate than Fatigue Load Model 1 when the simultaneous presence of several lorries on the bridge can be neglected for fatigue verifications. If that is not the case, it should be used only if it is supplemented by additional data. The National Annex may give the conditions of use of fatigue load models 1 and 2,
    4. Fatigue Load Models 3, 4 and 5 are intended to be used for fatigue life assessment by reference to fatigue strength curves defined in EN 1992 to EN 1999. They should not be used to check whether fatigue life can be considered as unlimited. For this reason, they are not numerically comparable to Fatigue Load Models 1 and 2. Fatigue Load Model 3 may also be used for the direct verification of designs by simplified methods in which the influence of the annual traffic volume and of some bridge dimensions is taken into account by a material-dependent adjustment factor λe.
    5. Fatigue Load Model 4 is more accurate than Fatigue Load Model 3 for a variety of bridges and of the traffic when the simultaneous presence of several lorries on the bridge can be neglected. If that is not the case, it should be used only if it is supplemented by additional data, specified or as defined in the National Annex.
    6. Fatigue Load Model 5 is the most general model, using actual traffic data.

      NOTE 3 The load values given for Fatigue Load Models 1 to 3 are appropriate for typical heavy traffic on European main roads or motorways (traffic category Number 1 as defined in Table 4.5).

      NOTE 4 The values of Fatigue Load Models 1 and 2 may be modified for the individual project or by the National Annex when considering other categories of traffic. In this case, the modifications made to both models should be proportional. For Fatigue Load Model 3 a modification depends on the verification procedure.

      45
  3. A traffic category on a bridge should be defined, for fatigue verifications, at least, by:
  4. For the assessment of general action effects (e.g. in main girders) all fatigue load models should be placed centrally on the notional lanes defined in accordance with the principles and rules given in 4.2.4(2) and (3). The slow lanes should be identified in the design.
  5. For the assessment of local action effects (e.g. in slabs) the models should be centered on notional lanes assumed to be located anywhere on the carriageway. However, where the transverse location of the vehicles for Fatigue Load Models 3, 4 and 5 is significant for the studied effects (e.g. for orthotropic decks), a statistical distribution of this transverse location should be taken into account in accordance with Figure 4.6. 46

    Figure 4.6 - Frequency distribution of transverse location of centre line of vehicle

    Figure 4.6 - Frequency distribution of transverse location of centre line of vehicle

  6. Fatigue Load Models 1 to 4 include dynamic load amplification appropriate for pavements of good quality (see annex B). An additional amplification factor Δφfat should be taken into account near expansion joints and applied to all loads :

Image

where :

D     is the distance (m) of the cross-section under consideration from the expansion joint. See Figure 4.7.

Figure 4.7 - Representation of the additional amplification factor

Figure 4.7 - Representation of the additional amplification factor

NOTE A conservative, often acceptable, simplification may consist of adopting Δφfat = 1,3 for any cross-section within 6m from the expansion joint. The dynamic additional amplification may be modified in the National Annex. Expression (4.7) is recommended.

47

4.6.2 Fatigue Load Model 1 (similar to LMl)

  1. Fatigue Load Model 1 has the configuration of the characteristic Load Model 1 defined in 4.3.2, with the values of the axle loads equal to 0,7Qik and the values of the uniformly distributed loads equal to 0,3qik and (unless otherwise specified) 0,3qrk.

    NOTE The load values for Fatigue Load Model 1 are similar to those defined for the Frequent Load Model. However adopting the Frequent Load Model without adjustment would have been excessively conservative by comparison with the other models, especially for large loaded areas. For individual projects, qrk may be neglected.

  2. The maximum and minimum stresses (σFLM, maxand σFLM, min) should be determined from the possible load arrangements of the model on the bridge.

4.6.3 Fatigue Load Model 2 (set of “frequent” lorries)

  1. Fatigue Load Model 2 consists of a set of idealised lorries, called “frequent” lorries, to be used as defined in (3) below.
  2. Each “frequent lorry” is defined by :
  3. The maximum and minimum stresses should be determined from the most severe effects of different lorries, separately considered, travelling alone along the appropriate lane.

NOTE When some of these lorries are obviously the most critical, the others may be disregarded.

48
Table 4.6 - Set of “frequent” lorries
1 2 3 4
LORRY SILHOUETTE Axle spacing
(m)
Frequent axle loads
(kN)
Wheel type (see Table 4.8)

Image

4,5 90
190
A
B

Image

4,20
1,30
80
140
140
A
B
B

Image

3,20
5,20
1,30
1,30
90
180
120
120
120
A
B
C
C
C

Image

3,40
6,00
1,80
90
190
140
140
A
B
B
B

Image

4,80
3,60
4,40
1,30
90
180
120
110
110
A
B
C
C
C

4.6.4 Fatigue Load Model 3 (single vehicle model)

  1. This model consists of four axles, each of them having two identical wheels. The geometry is shown in Figure 4.8. The weight of each axle is equal to 120 kN, and the contact surface of each wheel is a square of side 0,40 m.

    Figure 4.8 - Fatigue Load Model 3

    Figure 4.8 - Fatigue Load Model 3

    49
  2. The maximum and minimum stresses and the stress ranges for each cycle of stress fluctuation, i.e. their algebraic difference, resulting from the transit of the model along the bridge should be calculated.
  3. Where relevant, two vehicles in the same lane should be taken into account.

    NOTE The conditions of application of this rule may be defined in the National Annex or for the individual project. Possible recommended conditions are given hereafter :

4.6.5 Fatigue Load Model 4 (set of “standard” lorries)

  1. Fatigue Load Model 4 consists of sets of standard lorries which together produce effects equivalent to those of typical traffic on European roads. A set of lorries appropriate to the traffic mixes predicted for the route as defined in Tables 4.7 and 4.8 should be taken into account. 50
    Table 4.7 - Set of equivalent lorries
    VEHICLE TYPE TRAFFIC TYPE  
    1 2 3 4 5 6 7
          Long distance Medium distance Local traffic  
    LORRY Axle spacing (m) Equivalent axle loads (kN) Lorry percentage Lorry percentage Lorry percentage Wheel type

    Image

    4,5 70
    130
    20,0 40,0 80,0 A
    B

    Image

    4,20
    1,30
    70
    120
    120
    5,0 10,0 5,0 A
    B
    B

    Image

    3,20
    5,20
    1,30
    1,30
    70
    150
    90
    90
    90
    50,0 30,0 5,0 A
    B
    C
    C
    C

    Image

    3,40
    6,00
    1,80
    70
    140
    90
    90
    15,0 15,0 5,0 A
    B
    B
    B

    Image

    4,80
    3,60
    4,40
    1,30
    70
    130
    90
    80
    80
    10,0 5,0 5,0 A
    B
    C
    C
    C

    NOTE 1 This model, based on five standard lorries, simulates traffic which is deemed to produce fatigue damage equivalent to that due to actual traffic of the corresponding category defined in Table 4.5.

    NOTE 2 Other standard lorries and lorry percentages may be defined for the individual project or in the National Annex.

    NOTE 3 For the selection of a traffic type, it may broadly be considered that:

    In reality, mixture of traffic types may occur.

    51
    Table 4.8 - Definition of wheels and axles
    WHEEL/AXLE TYPE GEOMETRICAL DEFINITION
    A Image
    B Image
    C Image
  2. Each standard lorry is defined by :
  3. The calculations should be based on the following procedure :
  4. The stress range spectrum and the corresponding number of cycles from each fluctuation in stress during the passage of individual lorries on the bridge should be the Rainflow or the Reservoir counting method.
52

NOTE For verification rules, see EN 1992 to EN 1999

4.6.6 Fatigue Load Model 5 (based on recorded road traffic data)

  1. Fatigue Load Model 5 consists of the direct application of recorded traffic data, supplemented, if relevant, by appropriate statistical and projected extrapolations.

NOTE For the use of this model, see the National Annex. Guidance for a complete specification and the application of such a model is given in annex B.

4.7 Actions for accidental design situations

4.7.1 General

  1. P Loads due to road vehicles in accidental design situations shall be taken into account where relevant, resulting from :

4.7.2 Collision forces from vehicles under the bridge

NOTE See 5.6.2 and 6.7.2, and EN 1990, A2.

4.7.2.1 Collision forces on piers and other supporting members
  1. Forces due to the collision of abnormal height or aberrant road vehicles with piers or with the supporting members of a bridge should be taken into account.

    NOTE The National Annex may define :

    For stiff piers the following minimum values are recommended :

    1. Impact force : 1000 kN in the direction of vehicle travel or 500 kN perpendicular to that direction ;
    2. Height above the level of adjacent ground surface : 1,25 m. See also EN 1991-1-7.
4.7.2.2 Collision forces on decks
  1. If relevant the vehicle collision force should be specified.

NOTE 1 The National Annex may define the collision force on decks, possibly in relation to vertical clearance and other forms of protection. See EN 1991-1-7.

53

NOTE 2 Collision loads on bridge decks and other structural components over roads may vary widely depending on structural and non-structural parameters, and their conditions of applicability. The possibility of collision by vehicles having an abnormal or illegal height may have to be envisaged, as well as a crane swinging up while a vehicle is moving. Preventive or protective measures may be introduced as an alternative to designing for collision forces.

4.7.3 Actions from vehicles on the bridge

4.7.3.1 Vehicle on footways and cycle tracks on road bridges
  1. If a safety barrier of an appropriate containment level is provided, wheel or vehicle loading beyond this protection need not be taken into account.

    NOTE Containment levels for safety barriers are defined in EN 1317-2.

  2. Where the protection mentioned in (1) is provided, one accidental axle load corresponding to αQ2Q2k (see 4.3.2) should be so placed and oriented on the unprotected parts of the deck so as to give the most adverse effect adjacent to the safety barrier as shown, for example, in Figure 4.9. This axle load should not be taken into account simultaneously with any other variable load on the deck. A single wheel alone should be taken into account if geometrical constraints make a two-wheel arrangement impossible.

    Beyond the vehicle restraint system, the characteristic variable concentrated load defined in 5.3.2.2 should be applied, if relevant, separately from the accidental load.

    Figure 4.9 - Examples showing locations of loads from vehicles on footways and cycle tracks of road bridges

    Figure 4.9 - Examples showing locations of loads from vehicles on footways and cycle tracks of road bridges

    54
  3. In the absence of the protection mentioned in (1), the rules given in (2) are applicable up to the edge of the deck where a vehicle parapet is provided.
4.7.3.2 Collision forces on kerbs
  1. The action from vehicle collision with kerbs or pavement upstands should be taken as a lateral force equal to 100 kN acting at a depth of 0,05 m below the top of the kerb.

This force should be considered as acting on a line 0,5 m long and is transmitted by the kerbs to the structural members supporting them. In rigid structural members, the load should be assumed to have an angle of dispersal of 45°. When unfavourable, a vertical traffic load acting simultaneously with the collision force equal to 0,75αQ1Q1k (see Figure 4.10) should be taken into account.

Figure 4.10 - Definition of vehicle collision forces on kerbs

Figure 4.10 - Definition of vehicle collision forces on kerbs

4.7.3.3 Collision forces on vehicle restraint systems
  1. For structural design, horizontal and vertical forces transferred to the bridge deck by vehicle restraint systems should be taken into account.

    NOTE 1 The National Annex may define and select classes of collision forces and associated conditions of application. In the following, 4 recommended classes of values for the transferred horizontal force are given :

    Table 4.9(n) - Recommended classes for the horizontal force transferred by vehicle systems
    Recommended class Horizontal force (kN)
    A 100
    B 200
    C 400
    D 600
    55

    The horizontal force, acting transversely, may be applied 100 mm below the top of the selected vehicle restraint system or 1,0 m above the level of the carriageway or footway, whichever is the lower, and on a line 0,5 m long.

    NOTE 2 The values of the horizontal forces given for the classes A to D derive from measurements during collision tests on real vehicle restraint systems used for bridges. There is no direct correlation between these values and performance classes of vehicle restraint systems. The proposed values depend rather on the stiffness of the connection between the vehicle restraint system and the kerb or the part of the bridge to which it is connected. A very strong connection leads to the horizontal force given for class D. The lowest horizontal force derives from measurements for a vehicle restraint system with a weak connection. Such systems are frequently used for a steel vehicle restraint systems according to a performance class H2 according to EN 1317-2. A very weak connection may lead to the horizontal force given for class A.

    NOTE 3 The vertical force acting simultaneously with the horizontal collision force may be defined in the National Annex. The recommended values may be taken equal to 0.75αQ1Q1k. The calculations taking account of horizontal and vertical forces may be replaced, when possible, by detailing measures (for example, design of reinforcement).

  2. The structure supporting the vehicle parapet should be designed to sustain locally an accidental load effect corresponding to at least 1,25 times the characteristic local resistance of vehicle parapet (e.g. resistance of the connection of the parapet to the structure) and need not be combined with any other variable load.

    NOTE This design load effect may be defined in the National Annex. The value given in this clause (1,25) is a recommended minimum value.

4.7.3.4 Collision forces on structural members
  1. The vehicle collision forces on unprotected structural members above or beside the carriageway levels should be taken into account.

    NOTE These forces may the defined in the National Annex. It is recommended that they may be the same as defined in 4.7.2.1(1), acting 1,25 m above the carriageway level. However, when additional protective measures between the carriageway and these members are provided, this force may be reduced for the individual project.

  2. These forces should not be considered to act simultaneously with any variable load.

    NOTE For some intermediate members where damage to one of which would not cause collapse (e.g. hangers or stays), smaller forces may be defined for the individual project.

4.8 Actions on pedestrian parapets

  1. For structural design, forces that are transferred to the bridge deck by pedestrian parapets should be taken into account as variable loads and defined, depending on the selected loading class of the parapet.

    NOTE 1 For loading classes of pedestrian parapets, see EN 1317-6. For bridges, class C is the recommended minimum class.

    NOTE 2 The forces transferred to the bridge deck by pedestrian parapets may be defined with their classification for the individual project or in the National Annex in accordance with EN 1317-6. A line force of 1,0 kN/m acting, as a variable load, horizontally or vertically on the top of the parapet is a recommended minimum value for footways or footbridges. For service side paths, the recommended

    56

    minimum value is 0,8 kN/m. Exceptional and accidental cases are not covered by these recommended minimum values.

  2. For the design of the supporting structure, if pedestrian parapets are adequately protected against vehicle collision, the horizontal actions should be considered as simultaneous with the uniformly distributed vertical loads defined in 5.3.2.1.

    NOTE Pedestrian parapets can be considered as adequately protected only if the protection satisfies the requirements for the individual project.

  3. Where pedestrian parapets cannot be considered as adequately protected against vehicle collisions, the supporting structure should be designed to sustain an accidental load effect corresponding to 1,25 times the characteristic resistance of the parapet, exclusive of any variable load.

    NOTE This design load effect may be defined in the National Annex. The value given in this clause (1,25) is recommended.

4.9 Load models for abutments and walls adjacent to bridges

4.9.1 Vertical loads

  1. The carriageway located behind abutments, wing walls, side walls and other parts of the bridge in contact with earth, should be loaded with appropriate models.

    NOTE 1 These appropriate load models may be defined in the National Annex. The use of Load Model 1, defined in 4.3.2, is recommended, but, for simplicity, the tandem system loads may be replaced by an equivalent uniformly distributed load, noted qeq, spread over an appropriate relevant rectangular surface depending on the dispersal of the loads through the backfill or earth.

    NOTE 2 For the dispersal of the loads through the backfill or earth, see EN 1997. In the absence of any other rule, if the backfill is properly consolidated, the recommended value of the dispersal angle Image from the vertical Image is equal to 30°. With such a value, the surface on which qeq is applied may be taken as a rectangular surface 3 m wide and 2,20 m long.

  2. Representative values of the load model other than the characteristic values should not be considered.

4.9.2 Horizontal force

  1. No horizontal force should be taken into account at the surfacing level of the carriageway over the backfill.
  2. For the design of abutment upstand walls (see Figure 4.11), a longitudinal braking force should be taken into account with a characteristic value equal to 0,6αQ1Q1k, acting simultaneously with the αQ1Qlk axle loading of Load Model Number 1 and with the earth pressure from the backfill. The backfill should be assumed not to be loaded simultaneously.
57

Figure 4.11 - Definition of loads on upstand walls

Figure 4.11 - Definition of loads on upstand walls

58

Section 5 Actions on footways, cycle tracks and footbridges

5.1 Field of application

  1. Load models defined in this section are applicable to footways, cycle tracks and footbridges.
  2. The uniformly distributed load qfk (defined in 5.3.2.1) and the concentrated load Qfwk (defined in 5.3.2.2) should be used for road and railway bridges as well as for footbridges, where relevant (see 4.5, 4.7.3 and 6.3.6.2(1)). All other variable actions and actions for accidental design situations defined in this section are intended only for footbridges.

    NOTE 1 For loads on access steps, see 6.3 in EN 1991-1-1.

    NOTE 2 For large footbridges (for example more than 6 m width) load models defined in this section may not be appropriate and then complementary load models, with associated combination rules, may have to be defined for the individual project. Indeed, various human activities may take place on wide footbridges.

  3. Models and representative values given in this section should be used for serviceability and ultimate limit state calculations excluding fatigue limit states.
  4. For calculations relating to the vibration of pedestrian bridges and based on dynamic analysis, see 5.7. For all other calculations of load effects to be performed for any bridge type, the models and values given in this section include the dynamic amplification effects, and the variable actions should be treated as static.
  5. The effects of loads on construction sites are not intended to be covered by the load models given in this section and should be separately specified, where relevant.

5.2 Representation of actions

5.2.1 Models of the loads

  1. The imposed loads defined in this section result from pedestrian and cycle traffic, minor common construction and maintenance loads (e.g. service vehicles), and accidental situations. These loads give rise to vertical and horizontal, static and dynamic forces.

    NOTE 1 Loads due to cycle traffic are generally much lower than those due to pedestrian traffic, and the values given in this section are based on the frequent or occasional presence of pedestrians on cycle lanes. Special consideration may need to be given to loads due to horses or cattle for individual projects.

    NOTE 2 The load models defined in this section do not describe actual loads. They have been selected so that their effects (with dynamic amplification included where mentioned) represent the effects of actual traffic.

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  2. Actions for accidental design situations due to collision should be represented by static equivalent loads.

5.2.2 Loading classes

  1. Loads on footbridges may differ depending on their location and on the possible traffic flow of some vehicles. These factors are mutually independent and are considered in various clauses given below. Therefore no general classification of these bridges needs to be defined.

5.2.3 Application of the load models

  1. The same models, service vehicle excepted (see 5.3.2.3), should be used for pedestrian and cycle traffic on footbridges, on the areas of the deck of road bridges limited by pedestrian parapets and not included in the carriageway as defined in 1.4.2 (footways as defined in this Part of EN 1991) and on the footpaths of railway bridges.
  2. Other appropriate models should be defined for inspection gangways within the bridges and for platforms on railway bridges.

    NOTE Such models can be defined in the National Annex or for the individual project. The recommended models, to be used separately in order to get the most unfavourable effects, are an uniformly distributed load of 2 kN/m2 and a concentrated load of 3 kN applicable to a square surface of 0,20×0,20 m2.

  3. For each individual application, the models of vertical loads should be applied anywhere within the relevant areas so that the most adverse effect is obtained.

    NOTE In other terms, these actions are free actions.

5.3 Static models for vertical loads - characteristic values

5.3.1 General

  1. Characteristic loads are intended for the determination of pedestrian or cycle-track static load effects associated with ultimate limit-states verifications and particular serviceability verifications.
  2. Three models, mutually exclusive, should be taken into account, as relevant. They consist of:
  3. The characteristic values of these load models should be used for both persistent and transient design situations.
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5.3.2 Load Models

5.3.2.1 Uniformly distributed load
  1. For road bridges supporting footways or cycle tracks, a uniformly distributed load qfk should be defined (Figure 5.1).

    Figure 5.1 - Characteristic load on a footway (or cycle track)

    Figure 5.1 - Characteristic load on a footway (or cycle track)

    NOTE The characteristic value qfk may be defined in the National Annex or for the individual project. The recommended value is qfk = 5 kN/m2.

  2. For the design of footbridges, a uniformly distributed load qfk should be defined and applied only in the unfavourable parts of the influence surface, longitudinally and transversally.

NOTE Load Model 4 (crowd loading) defined in 4.3.5, corresponding to qfk = 5 kN/m2, may be specified to cover the static effects of a continuous dense crowd where such a risk exists. Where the application of Load Model 4 defined in 4.3.5 is not required for footbridges, the recommended value for qfk is :

Image

where :

L     is the loaded length in [m].

5.3.2.2 Concentrated load
  1. The characteristic value of the concentrated load Qfwk should be taken equal to 10 kN acting on a square surface of sides 0,10 m.

    NOTE The characteristic value of the load as well as the dimensions may be adjusted in the National Annex. The values in this clause are recommended.

  2. Where, in a verification, general and local effects can be distinguished, the concentrated load should be taken into account only for local effects. 61
  3. If, for a footbridge, a service vehicle, as mentioned in 5.3.2.3 is specified, Qfwk should not be considered.
5.3.2.3 Service vehicle
  1. P When service vehicles are to be carried on a footbridge or footway, one service vehicle Qserv shall be taken into account.

NOTE l This vehicle may be a vehicle for maintenance, emergencies (e.g. ambulance, fire) or other services. The characteristics of this vehicle (axle weight and spacing, contact area of wheels), the dynamic amplification and all other appropriate loading rules may be defined for the individual project or in the National Annex. If no information is available and if no permanent obstacle prevents a vehicle being driven onto the bridge deck, the use of the vehicle defined in 5.6.3 as the service vehicle (characteristic load) is recommended ; in this case, there will be no need to apply 5.6.3, i.e. to consider the same vehicle as accidental.

NOTE 2 Service vehicle needs not be considered if permanent provisions are made to prevent access of all vehicles to the footbridge.

NOTE 3 Several service vehicles, mutually exclusive, may have to be taken into account and may be defined for the individual project.

5.4 Static model for horizontal forces - Characteristic values

  1. For footbridges only, a horizontal force Qflk should be taken into account, acting along the bridge deck axis at the pavement level.
  2. The characteristic value of the horizontal force should be taken equal to the greater of the following two values :

    NOTE The characteristic value of the horizontal force may be defined in the National Annex or for the individual project. The values in this clause are recommended.

  3. The horizontal force is considered as acting simultaneously with the corresponding vertical load, and in no case with the concentrated load Qfwk.

NOTE This force is normally sufficient to ensure the horizontal longitudinal stability of footbridges. It does not ensure horizontal transverse stability, which should be ensured by considering other actions or by appropriate design measures.

5.5 Groups of traffic loads on footbridges

  1. When relevant, the vertical loads and horizontal forces due to traffic should be taken into account by considering groups of loads defined in Table 5.1. Each of these groups of loads, which are mutually exclusive, should be considered as defining a characteristic action for combination with non-traffic loads. 62
    Table 5.1 - Definition of groups of loads (characteristic values)
    Load type Vertical forces Horizontal forces
    Load system Uniformly distributed load Service vehicle  
    Groups of loads grl qfk 0 Qflk
    gr2 0 Qserv Qflk
  2. For any combination of traffic loads together with actions specified in other Parts of EN 1991, any such group should be considered as one action.

NOTE For the individual components of the traffic loads on footbridges, the other representative values are defined in EN 1990, A2.

5.6 Actions for accidental design situations for footbridges

5.6.1 General

  1. Such actions are due to :

NOTE Other collision forces (see 2.3) may be defined for the individual project or in the National Annex.

5.6.2 Collision forces from road vehicles under the bridge

  1. The measures to protect a footbridge should be defined.

    NOTE Footbridges (piers and decks) are generally much more sensitive to collision forces than road bridges. Designing them for the same collision load may be unrealistic. The most effective way to take collision into account generally consists of protecting the footbridges :

5.6.2.1 Collision forces on piers
  1. Forces due to the collision of abnormal height or aberrant road vehicles with piers or with the supporting members of a footbridge or ramps or stairs should be taken into account.

    NOTE The National Annex may define :

    For stiff piers the following minimum values are recommended :

    1. Impact force : 1000 kN in the direction of vehicle travel or 500 kN perpendicular to that direction ;
    2. Height above the level of adjacent ground surface : 1,25 m.

See also EN 1991-1-7.

5.6.2.2 Collision forces on decks
  1. An adequate vertical clearance between the ground surface and the soffit of the deck above should be ensured in the design, when relevant.

NOTE 1 The National Annex or the individual project may define collision forces depending on the vertical clearance. See also EN 1991-1-7.

NOTE 2 The possibility of collision by vehicles having an abnormal or illegal height may have to be taken into account.

5.6.3 Accidental presence of vehicles on the bridge

  1. P If no permanent obstacle prevents a vehicle from being driven onto the bridge deck, the accidental presence of a vehicle on the bridge deck shall be taken into account.
  2. For such a situation, the following load model should be used, consisting of a two-axle load group of 80 and 40 kN, separated by a wheel base of 3 m (Figure 5.2), with a track (wheel-centre to wheel-centre) of 1,3 m and square contact areas of side 0,2m at coating level. The braking force associated with the load model should be 60% of the vertical load.

    Figure 5.2 - Accidental loading

    Figure 5.2 - Accidental loading

    NOTE 1 See the note in 5.3.2.3-(1)P.

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    NOTE 2 If relevant, other characteristics of the load model may be defined in the National Annex or for the individual project. The model defined in this clause is recommended.

  3. No variable action should be taken into account simultaneously with the load model defined in 5.6.3(2).

5.7 Dynamic models of pedestrian loads

  1. Depending on the dynamic characteristics of the structure, the relevant natural frequencies (corresponding to vertical, horizontal, torsional vibrations) of the main structure of the bridge deck should be determined from an appropriate structural model.

    NOTE Vibrations of footbridges may have various origins, e.g. pedestrians, who can walk, run, jump or dance, wind, vandals, etc.

  2. Forces exerted by pedestrians with a frequency identical to one of the natural frequencies of the bridge can result into resonance and need to be taken into account for limit state verifications in relation with vibrations.

    NOTE Effects of pedestrian traffic on a footbridge depend on various factors as, for example, the number and location of people likely to be simultaneously on the bridge, and also on external circumstances, more or less linked to the location of the bridge. In the absence of significant response of the bridge, a pedestrian normally walking exerts on it the following simultaneous periodic forces :

  3. Appropriate dynamic models of pedestrian loads and comfort criteria should be defined.

NOTE The dynamic models of pedestrian loads and associated comfort criteria may be defined in the National Annex or for the individual project. See also EN 1990, A2.

5.8 Actions on parapets

  1. For footbridges, pedestrian parapets should be designed in accordance with rules given in 4.8.

5.9 Load model for abutments and walls adjacent to bridges

  1. The area external to a carriageway and located behind abutments, wing walls, side walls and other parts of the bridge in contact with earth, should be loaded with a uniformly distributed vertical load of 5 kN/m2.

NOTE 1 This load does not cover the effects of heavy construction vehicles and other lorries commonly used for the placing of the backfill.

NOTE 2 The characteristic value may be adjusted for the individual project.

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Section 6 Rail traffic actions and other actions specifically for railway bridges

6.1 Field of application

  1. P This section applies to rail traffic on the standard track gauge and wide track gauge European mainline network.
  2. The load models defined in this section do not describe actual loads. They have been selected so that their effects, with dynamic enhancements taken into account separately, represent the effects of service traffic. Where traffic outside the scope of the load models specified in this Part needs to be considered, then alternative load models, with associated combination rules, should be specified.

    NOTE The alternative load models with associated combination rules may be defined in the National Annex or for the individual project.

  3. P This section is not applicable for actions due to:
  4. Requirements are specified in EN 1990 A2 for the limits of deformation of structures carrying rail traffic to maintain the safety of operations and to ensure the comfort of passengers etc..
  5. Three standard mixes of rail traffic are given as a basis for calculating the fatigue life of structures (see annex D).
  6. The self-weight of non-structural elements includes the weight of elements such as, for example, noise and safety barriers, signals, ducts, cables and overhead line equipment (except the forces due to the tension of the contact wire etc.).
  7. The design should pay special attention to temporary bridges because of the flexibility of some types of temporary structures. The loading and requirements for the design of temporary bridges should be specified.

NOTE The loading requirements for the design of temporary railway bridges, which may generally be based on this document, may be specified in the National Annex or for the individual project. Special requirements may also be given in the National Annex or for the individual project for temporary bridges depending upon the conditions in which they are used (e.g. special requirements are needed for skew bridges).

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6.2 Representation of actions – nature of rail traffic loads

  1. General rules are given for the calculation of the associated dynamic effects, centrifugal forces, nosing force, traction and braking forces and aerodynamic actions due to passing rail traffic.
  2. Actions due to railway operations are given for:

    NOTE Guidance is given on the evaluation of the combined response of structure and track to variable actions (6.5.4).

  3. Derailment actions for Accidental Design Situations are given for:

6.3 Vertical loads - Characteristic values (static effects) and eccentricity and distribution of loading

6.3.1 General

  1. Rail traffic actions are defined by means of load models. Five models of railway loading are given:
  2. Provision is made for varying the specified loading to allow for differences in the nature, volume and maximum weight of rail traffic on different railways, as well as different qualities of track.

6.3.2 Load Model 71

  1. Load Model 71 represents the static effect of vertical loading due to normal rail traffic.
  2. P The load arrangement and the characteristic values for vertical loads shall be taken as shown in Figure 6.1. 67

    Figure 6.1 - Load Model 71 and characteristic values for vertical loads

    Figure 6.1 - Load Model 71 and characteristic values for vertical loads

  3. P The characteristic values given in Figure 6.1 shall be multiplied by a factor α, on lines carrying rail traffic which is heavier or lighter than normal rail traffic. When multiplied by the factor α the loads are called “classified vertical loads”. This factor α shall be one of the following:

    0,75 - 0,83 - 0,91 - 1,00 - 1,10 - 1,21 - 1,33 - 1.46

    The actions listed below shall be multiplied by the same factor α:

  4. P For checking limits of deflection classified vertical loads and other actions enhanced by α in accordance with 6.3.2(3) shall be used (except for passenger comfort where α shall be taken as unity).

6.3.3 Load Models SW/0 and SW/2

  1. Load Model SW/0 represents the static effect of vertical loading due to normal rail traffic on continuous beams.
  2. Load Model SW/2 represents the static effect of vertical loading due to heavy rail traffic.
  3. P The load arrangement shall be taken as shown in Figure 6.2, with the characteristic values of the vertical loads according to Table 6.1. 68

    Figure 6.2 - Load Models SW/0 and SW/2

    Figure 6.2 - Load Models SW/0 and SW/2

    Table 6.1 - Characteristic values for vertical loads for Load Models SW/0 and SW/2
    Load Model qvk [kN/m] a [m] c [m]
    SW/0 133 15,0 5,3
    SW/2 150 25,0 7,0
  4. P The lines or section of line over which heavy rail traffic may operate where Load Model SW/2 shall be taken into account shall be designated.

    NOTE The designation may be made in the National Annex or for the individual project.

  5. P Load Model SW/0 shall be multiplied by the factor α in accordance with 6.3.2(3).

6.3.4 Load Model “unloaded train”

  1. For some specific verifications (see EN 1990 A2, § 2.2.4(2)) a particular load model is used, called “unloaded train”. The Load Model “unloaded train” consists of a vertical uniformly distributed load with a characteristic value of 10,0 kN/m.

6.3.5 Eccentricity of vertical loads (Load Models 71 and SW/0)

  1. P The effect of lateral displacement of vertical loads shall be considered by taking the ratio of wheel loads on all axles as up to 1,25:1,00 on any one track. The resulting eccentricity e is shown in Figure 6.3.

Eccentricity of vertical loads may be neglected when considering fatigue.

NOTE Requirements for taking into account the position and tolerance in position of tracks are given in 6.8.1.

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Figure 6.3 - Eccentricity of vertical loads

Figure 6.3 - Eccentricity of vertical loads

6.3.6 Distribution of axle loads by the rails, sleepers and ballast

  1. Subclauses 6.3.6.1 to 6.3.6.3 are applicable to Real Trains, Fatigue Trains, Load Models 71, SW/0, SW/2, the “unloaded train” and HSLM except where stated otherwise.
6.3.6.1 Longitudinal distribution of a point force or wheel load by the rail
  1. A point force in Load Model 71 (or classified vertical load in accordance with 6.3.2(3) where required) and HSLM (except for HSLM-B) or wheel load may be distributed over three rail support points as shown in Figure 6.4 below:

Figure 6.4 - Longitudinal distribution of a point force or wheel load by the rail

Figure 6.4 - Longitudinal distribution of a point force or wheel load by the rail

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6.3.6.2 Longitudinal distribution of load by sleepers and ballast
  1. Generally the point loads of Load Model 71 only (or classified vertical load in accordance with 6.3.2(3) where required) or an axle load may be distributed uniformly in the longitudinal direction (except where local load effects are significant, e.g. for the design of local floor elements, etc.).
  2. For the design of local floor elements etc. (e.g. longitudinal and transverse ribs, rail bearers, cross girders, deck plates, thin concrete slabs, etc.), the longitudinal distribution beneath sleepers as shown in Figure 6.5 should be taken into account, where the reference plane is defined as the upper surface of the deck.

Figure 6.5 - Longitudinal distribution of load by a sleeper and ballast

Figure 6.5 - Longitudinal distribution of load by a sleeper and ballast

6.3.6.3 Transverse distribution of actions by the sleepers and ballast
  1. On bridges with ballasted track without cant, the actions should be distributed transversely as shown in Figure 6.6. 71

    Figure 6.6 - Transverse distribution of actions by the sleepers and ballast, track without cant (effect of eccentricity of vertical loads not shown)

    Figure 6.6 - Transverse distribution of actions by the sleepers and ballast, track without cant (effect of eccentricity of vertical loads not shown)

  2. On bridges with ballasted track (without cant) and full length sleepers, where the ballast is only consolidated under the rails, or for duo-block sleepers, the actions should be distributed transversely as shown in Figure 6.7.

    Figure 6.7 - Transverse distribution of actions by the sleepers and ballast, track without cant (effect of eccentricity of vertical loads not shown)

    Figure 6.7 - Transverse distribution of actions by the sleepers and ballast, track without cant (effect of eccentricity of vertical loads not shown)

  3. On bridges with ballasted track with cant the actions should be distributed transversely as shown in Figure 6.8. 72

    Figure 6.8 - Transverse distribution of actions by the sleepers and ballast, track with cant (effect of eccentricity of vertical loads not shown)

    Figure 6.8 - Transverse distribution of actions by the sleepers and ballast, track with cant (effect of eccentricity of vertical loads not shown)

  4. On bridges with ballasted track and cant and for full length sleepers, where the ballast is only consolidated under the rails, or for duo-block sleepers, Figure 6.8 should be modified to take into account the transverse load distribution under each rail shown in Figure 6.7.
  5. The transverse distribution to be used should be specified.

NOTE The individual project may specify the transverse distribution to be used.

6.3.6.4 Equivalent vertical loading for earthworks and earth pressure effects
  1. For global effects, the equivalent characteristic vertical loading due to rail traffic actions for earthworks under or adjacent to the track may be taken as the appropriate load model (LM71 (or classified vertical load in accordance with 6.3.2(3) where required) and SW/2 where required) uniformly distributed over a width of 3,00 m at a level 0,70 m below the running surface of the track.
  2. No dynamic factor or enhancement needs to be applied to the above uniformly distributed load.
  3. For the design of local elements close to a track (e.g. ballast retention walls), a special calculation should be carried out taking into account the maximum local vertical, longitudinal and transverse loading on the element due to rail traffic actions.
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6.3.7 Actions for non-public footpaths

NOTE The individual project may specify alternative requirements for non-public footpaths, maintenance walkways or platforms etc.

  1. Non-public footpaths are those designated for use by only authorised persons.
  2. Pedestrian, cycle and general maintenance loads should be represented by a uniformly distributed load with a characteristic value qfk = 5 kN/m2.
  3. For the design of local elements a concentrated load Qk = 2,0 kN acting alone should be taken into account and applied on a square surface with a 200 mm side.
  4. Horizontal forces on parapets, partition walls and barriers due to persons should be taken as category B and C1 of EN 1991 -1 -1.

6.4 Dynamic effects (including resonance)

6.4.1 Introduction

  1. The static stresses and deformations (and associated bridge deck acceleration) induced in a bridge are increased and decreased under the effects of moving traffic by the following:
  2. P For determining the effects (stresses, deflections, bridge deck acceleration etc.) of rail traffic actions the above effects shall be taken into account.

6.4.2 Factors influencing dynamic behaviour

  1. The principal factors which influence dynamic behaviour are:
    1. the speed of traffic across the bridge,
    2. the span L of the element and the influence line length for deflection of the element being considered,
    3. the mass of the structure,
    4. the natural frequencies of the whole structure and relevant elements of the structure and the associated mode shapes (eigenforms) along the line of the track,
    5. the number of axles, axle loads and the spacing of axles,
    6. the damping of the structure,
    7. vertical irregularities in the track,
    8. the unsprung/sprung mass and suspension characteristics of the vehicle, 74
    9. the presence of regularly spaced supports of the deck slab and/or track (cross girders, sleepers etc.),
    10. vehicle imperfections (wheel flats, out of round wheels, suspension defects etc.),
    11. the dynamic characteristics of the track (ballast, sleepers, track components etc.).

These factors are taken into account in 6.4.4 to 6.4.6.

NOTE There are no specific deflection limits specified for avoiding resonance and excessive vibration effects. See EN 1990 A2 for deflection criteria for traffic safety and passenger comfort etc.

6.4.3 General design rules

  1. P A static analysis shall be carried out with the load models defined in 6.3 (LM71 and where required Load Models SW/0 and SW/2). The results shall be multiplied by the dynamic factor Φ defined in 6.4.5 (and if required multiplied by α in accordance with 6.3.2).
  2. The criteria for determining whether a dynamic analysis is required are given in 6.4.4.
  3. P Where a dynamic analysis is required:
  4. All bridges where the Maximum Line Speed at the Site is greater than 200 km/h or where a dynamic analysis is required should be designed for characteristic values of Load Model 71 (and where required Load Model SW/0) or classified vertical loads with α ≥ 1 in accordance with 6.3.2.
  5. For passenger trains the allowances for dynamic effects in 6.4.4 to 6.4.6 are valid for Maximum Permitted Vehicle Speeds up to 350 km/h.

6.4.4 Requirement for a static or dynamic analysis

  1. The requirements for determining whether a static or a dynamic analysis is required are shown in Figure 6.9.

NOTE The National Annex may specify alternative requirements. The use of the flow chart in Figure 6.9 is recommended.

75

Figure 6.9 - Flow chart for determining whether a dynamic analysis is required

Figure 6.9 - Flow chart for determining whether a dynamic analysis is required

76

where:

V is the Maximum Line Speed at the Site [km/h]
L is the span length [m]
n0 is the first natural bending frequency of the bridge loaded by permanent actions [Hz]
nT is the first natural torsional frequency of the bridge loaded by permanent actions [Hz]
v is the Maximum Nominal Speed [m/s]
(v/no)lim is given in annex F

NOTE l Valid for simply supported bridges with only longitudinal line beam or simple plate behaviour with negligible skew effects on rigid supports.

NOTE 2 For Tables Fl and F2 and associated limits of validity see annex F.

NOTE 3 A dynamic analysis is required where the Frequent Operating Speed of a Real Train equals a Resonant Speed of the structure. See 6.4.6.6 and annex F.

NOTE 4 φdyn is the dynamic impact component for Real Trains for the structure given in 6.4.6.5(3).

NOTE 5 Valid providing the bridge meets the requirements for resistance, deformation limits given in EN 1990 A2.4.4 and the maximum coach body acceleration (or associated deflection limits) corresponding to a very good standard of passenger comfort given in EN 1990 A2.

NOTE 6 For bridges with a first natural frequency n0 within the limits given by Figure 6.10 and a Maximum Line Speed at the Site not exceeding 200km/h, a dynamic analysis is not required.

NOTE 7 For bridges with a first natural frequency n0 exceeding the upper limit (1) in Figure 6.10 a dynamic analysis is required. Also see 6.4.6.1.1 (7).

Figure 6.10 - Limits of bridge natural frequency n0 [Hz] as a function of L [m]

Figure 6.10 - Limits of bridge natural frequency n0 [Hz] as a function of L [m]

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NOTE 8 For a simply supported bridge subjected to bending only, the natural frequency may be estimated using the formula :

Image

where:

δ0 is the deflection at mid span due to permanent actions [mm] and is calculated, using a short term modulus for concrete bridges, in accordance with a loading period appropriate to the natural frequency of the bridge.

6.4.5 Dynamic factor Φ(Φ2, Φ3)

6.4.5.1 Field of application
  1. The dynamic factor Φ takes account of the dynamic magnification of stresses and vibration effects in the structure but does not take account of resonance effects.
  2. P Where the criteria specified in 6.4.4 are not satisfied there is a risk that resonance or excessive vibration of the bridge may occur (with a possibility of excessive deck accelerations leading to ballast instability etc. and excessive deflections and stresses etc.). For such cases a dynamic analysis shall be carried out to calculate impact and resonance effects.

    NOTE Quasi static methods which use static load effects multiplied by the dynamic factor Φ defined in 6.4.5 are unable to predict resonance effects from high speed trains. Dynamic analysis techniques, which take into account the time dependant nature of the loading from the High Speed Load Model (HSLM) and Real Trains (e.g. by solving equations of motion) are required for predicting dynamic effects at resonance.

  3. Structures carrying more than one track should be considered without any reduction of dynamic factor Φ.
6.4.5.2 Definition of the dynamic factor Φ
  1. P The dynamic factor Φ which enhances the static load effects under Load Models 71, SW/0 and SW/2 shall be taken as either Φ2 or Φ3
  2. Generally the dynamic factor Φ is taken as either Φ2 or Φ3 according to the quality of track maintenance as follows:
    1. For carefully maintained track:

      Image

      with: 1,00 ≤ Φ2 ≤ 1,67

    2. For track with standard maintenance:

      Image

      78

      with: 1,00 ≤ Φ3 ≤ 2,0

      where:

      LΦ “Determinant” length (length associated with Φ) defined in Table 6.2 [m].

      NOTE The dynamic factors were established for simply supported girders. The length LΦ allows these factors to be used for other structural members with different support conditions.

  3. P If no dynamic factor is specified Φ3 shall be used.

    NOTE The dynamic factor to be used may be specified in the National Annex or for the individual project.

  4. P The dynamic factor Φ shall not be used with:
6.4.5.3 Determinant length LΦ
  1. The determinant lengths LΦ to be used are given in the Table 6.2 below.

    NOTE Alternative values of LΦ may be specified in the National Annex. The values given in Table 6.2 are recommended.

  2. Where no value of LΦ is specified in Table 6.2 the determinant length should be taken as the length of the influence line for deflection of the element being considered or alternative values should be specified.

    NOTE The individual project may specify alternative values.

  3. If the resultant stress in a structural member depends on several effects, each of which relates to a separate structural behaviour, then each effect should be calculated using the appropriate determinant length.
79
Table 6.2 - Determinant lengths LΦ
Case Structural element Determinant length LΦ
Steel deck plate: closed deck with ballast bed (orthotropic deck plate) (for local and transverse stresses)
  Deck with cross girders and continuous longitudinal ribs:  
1.1 Deck plate (for both directions) 3 times cross girder spacing
1.2 Continuous longitudinal ribs (including small cantilevers up to 0,50 m)a 3 times cross girder spacing
1.3 Cross girders Twice the length of the cross girder
1.4 End cross girders 3,6mb
  Deck plate with cross girders only:  
2.1 Deck plate (for both directions) Twice cross girder spacing + 3 m
2.2 Cross girders Twice cross girder spacing + 3 m
2.3 End cross girders 3,6mb
Steel grillage: open deck without ballast bed b for local and transverse stresses)
3.1 Rail bearers:
  • – as an element of a continuous grillage
  • – simply supported


3 times cross girder spacing

Cross girder spacing + 3 m
3.2 Cantilever of rail bearera 3,6m
3.3 Cross girders (as part of cross girder/ continuous rail bearer grillage) Twice the length of the cross girder
3.4 End cross girders 3,6mb
  1. In general all cantilevers greater than 0,50 m supporting rail traffic actions need a special study in accordance with 6.4.6 and with the loading agreed with the relevant authority specified in the National Annex.
  2. It is recommended to apply Φ3
80
Concrete deck slab with ballast bed (for local and transverse stresses)
4.1 Deck slab as part of box girder or upper flange of main beam
  • – spanning transversely to the main girders
  • – spanning in the longitudinal direction
  • – cross girders
  • – transverse cantilevers supporting railway loading


3 times span of deck plate

3 times span of deck plate

Twice the length of the cross girder

Figure 6.11 - Transverse cantilever supporting railway loading

Figure 6.11 - Transverse cantilever supporting railway loading

4.2 Deck slab continuous (in main girder direction) over cross girders Twice the cross girder spacing
4.3 Deck slab for half through and trough bridges:
  • – spanning perpendicular to the main girders
  • – spanning in the longitudinal direction


Twice span of deck slab + 3m

Twice span of deck slab
4.4 Deck slabs spanning transversely between longitudinal steel beams in filler beam decks Twice the determinant length in the longitudinal direction
4.5 Longitudinal cantilevers of deck slab
  • e ≤ 0,5 m: 3,6mb
  • e > 0,5 m:a
4.6 End cross girders or trimmer beams 3,6m b
  1. In general all cantilevers greater than 0,50 m supporting rail traffic actions need a special study in accordance with 6.4.6 and with the loading agreed with the relevant authority specified in the National Annex.
  2. It is recommended to apply Φ3

    NOTE For Cases 1.1 to 4.6 inclusive LΦ is subject to a maximum of the determinant length of the main girders.

81
Main girders
5.1 Simply supported girders and slabs (including steel beams embedded in concrete) Span in main girder direction
5.2 Girders and slabs continuous over n spans with

Lm = 1/n (L1 + L2 + .. + Ln)     (6.6)
LΦ = k × Lm,     (6.7)
but not less than max Li (i = 1,…, n)

Image
5.3 Portal frames and closed frames or boxes:  
– single-span Consider as three-span continuous beam (use 5.2, with vertical and horizontal lengths of members of the frame or box)
– multi-span Consider as multi-span continuous beam (use 5.2, with lengths of end vertical members and horizontal members)
5.4 Single arch, archrib, stiffened girders of bowstrings Half span
5.5 Series of arches with solid spandrels retaining fill Twice the clear opening
5.6 Suspension bars (in conjunction with stiffening girders) 4 times the longitudinal spacing of the suspension bars
Structural supports
6 Columns, trestles, bearings, uplift bearings, tension anchors and for the calculation of contact pressures under bearings. Determinant length of the supported members
6.4.5.4 Reduced dynamic effects
  1. In the case of arch bridges and concrete bridges of all types with a cover of more than 1,00 m, Φ2 and Φ3 may be reduced as follows:

    Image

    where:

    82
    h is the height of cover including the ballast from the top of the deck to the top of the sleeper, (for arch bridges, from the crown of the extrados) [m].
  2. The effects of rail traffic actions on columns with a slenderness (buckling length/radius of gyration) < 30, abutments, foundations, retaining walls and ground pressures may be calculated without taking into account dynamic effects.

6.4.6 Requirements for a dynamic analysis

6.4.6.1 Loading and load combinations
6.4.6.1.1 Loading
  1. P The dynamic analysis shall be undertaken using characteristic values of the loading from the Real Trains specified. The selection of Real Trains shall take into account each permitted or envisaged train formation for every type of high speed train permitted or envisaged to use the structure at speeds over 200km/h.

    NOTE 1 The individual project may specify the characteristic axle loads and spacings for each configuration of each required Real Train.

    NOTE 2 Also see 6.4.6.1.1(7) for loading where a dynamic analysis is required for a Maximum Line Speed at the Site less than 200km/h.

  2. P The dynamic analysis shall also be undertaken using Load Model HSLM on bridges designed for international lines where European high speed interoperability criteria are applicable.

    NOTE The individual project may specify when Load Model HSLM is to be used.

  3. Load Model HSLM comprises of two separate Universal Trains with variable coach lengths, HSLM-A and HSLM-B.

    NOTE HSLM-A and HSLM-B together represent the dynamic load effects of articulated, conventional and regular high speed passenger trains in accordance with the requirements for the European Technical Specification for Interoperability given in E.1.

  4. HSLM-A is defined in Figure 6.12 and Table 6.3: 83

    Figure 6.12 - HSLM-A

    Figure 6.12 - HSLM-A

    Table 6.3 - HSLM-A
    Universal Train Number of intermediate coaches
    N
    Coach length
    D[m]
    Bogie axle spacing
    d [m]
    Point force
    P[kN]
    Al 18 18 2,0 170
    A2 17 19 3,5 200
    A3 16 20 2,0 180
    A4 15 21 3,0 190
    A5 14 22 2,0 170
    A6 13 23 2,0 180
    A7 13 24 2,0 190
    A8 12 25 2,5 190
    A9 11 26 2,0 210
    A10 11 27 2,0 210
  5. HSLM-B comprises of N number point forces of 170 kN at uniform spacing d [m] where N and d are defined in Figures 6.13 and 6.14:

    Figure 6.13 - HSLM-B

    Figure 6.13 - HSLM-B

    84

    Figure 6.14 - HSLM-B

    Figure 6.14 - HSLM-B

    where L is the span length [m].

  6. Either HSLM-A or HSLM-B should be applied in accordance with the requirements of Table 6.4:
    Table 6.4 - Application of HSLM-A and HSLM-B
    Structural configuration Span
    L <7m L ≥7m
    Simply supported spana HSLM-Bb HSLM-Ac
    Continuous structurea

    or

    Complex structuree
    HSLM-A
    Trains A1 to A10
    inclusived
    HSLM-A
    Trains Al to A10 inclusived
    1. Valid for bridges with only longitudinal line beam or simple plate behaviour with negligible skew effects on rigid supports.
    2. For simply supported spans with a span of up to 7 m a single critical Universal Train from HSLM-B may be used for the analysis in accordance with 6.4.6.1.1(5).
    3. For simply supported spans with a span of 7 m or greater a single critical Universal Train from HSLM-A may be used for the dynamic analysis in accordance with annex E (Alternatively Universal trains Al to A10 inclusive may be used).
    4. All Trains Al to A10 inclusive should be used in the design.
    5. Any structure that does not comply with Note a above. For example a skew structure, bridge with significant torsional behaviour, half through structure with significant floor and main girder vibration modes etc. In addition, for complex structures with significant floor vibration modes (e.g. half through or through bridges with shallow floors) HSLM-B should also be applied.

    NOTE The National Annex or the individual project may specify additional requirements relating to the application of HSLM-A and HSLM-B to continuous and complex structures.

    85
  7. Where the frequency limits of Figure 6.10 are not satisfied and the Maximum Line Speed at the Site is ≤ 200 km/h a dynamic analysis should be carried out. The analysis should take into account the behaviours identified in 6.4.2 and consider:

NOTE The loading and methodology for the analysis may be specified for the individual project and should be agreed with the relevant authority specified in the National Annex.

6.4.6.1.2 Load combinations and partial factors
  1. For the dynamic analysis the calculation of the value of mass associated with self weight and removable loads (ballast etc.) should use nominal values of density.
  2. P For the dynamic analysis loads according to 6.4.6.1.1(1) and (2) and where required 6.4.6.1.1(7) shall be used.
  3. For the dynamic analysis of the structure only, one track (the most adverse) on the structure should be loaded in accordance with Table 6.5.
    Table 6.5 - Summary of additional load cases depending upon number of tracks on bridge
    Number of tracks on a bridge Loaded track Loading for dynamic analysis
    1 one Each Real Train and Load Model HSLM (if required) travelling in the permitted direction(s) of travel.
    2 (Trains normally travelling in opposite directions)a either track Each Real Train and Load Model HSLM (if required) travelling in the permitted direction(s) of travel.
    other track None.
    a For bridges carrying 2 tracks with trains normally travelling in the same directions or carrying 3 or more tracks with a Maximum Line Speed at the Site exceeding 200km/h the loading should be agreed with the relevant authority specified in the National Annex.
  4. Where the load effects from a dynamic analysis exceed the effects from Load Model 71 (and Load Model SW/0 for continuous structures) in accordance with 6.4.6.5(3) on a track the load effects from a dynamic analysis should be combined with:
  5. P Where the load effects from a dynamic analysis exceed the effects from Load Model 71 (and Load Model SW/0 for continuous structures) in accordance with 6.4.6.5(3) the dynamic rail loading effects (bending moments, shears, deformations etc. excluding acceleration) determined from the dynamic analysis shall be enhanced by the partial factors given in A2 of EN 1990.
  6. P Partial factors shall not be applied to the loading given in 6.4.6.1.1 when determining bridge deck accelerations. The calculated values of acceleration shall be directly compared with the design values in 6.4.6.5.
  7. For fatigue, a bridge should be designed for the additional fatigue effects at resonance from the loading in accordance with 6.4.6.1.1 on any one track. See 6.4.6.6.
6.4.6.2 Speeds to be considered
  1. P For each Real Train and Load Model HSLM a series of speeds up to the Maximum Design Speed shall be considered. The Maximum Design Speed shall be generally 1,2 × Maximum Line Speed at the site.

    The Maximum Line Speed at the site shall be specified.

    NOTE 1 The individual project may specify the Maximum Line Speed at the site.

    NOTE 2 Where specified for the individual project a reduced speed may be used for checking individual Real Trains for 1,2 × their associated Maximum Permitted Vehicle Speed.

    NOTE 3 It is recommended that the individual project specify an increased Maximum Line Speed at the Site to take into account potential modifications to the infrastructure and future rolling stock.

    NOTE 4 Structures can exhibit a highly peaked response due to resonance effects. Where there is a likelihood of train overspeeding and exceeding either the Maximum Permitted Vehicle Speed or the current or envisaged Maximum Line Speed at the Site it is recommended that the individual project specify an additional factor for increasing the Maximum Design Speed to be used in the dynamic analysis.

    NOTE 5 It is recommended that the individual project specify additional requirements for checking structures where there is a requirement for a section of line to be suitable for commissioning tests of a Real Train. The Maximum Design Speed used for the Real Train should be at least 1,2 × Maximum Train Commissioning Speed. Calculations are required to demonstrate that safety considerations (maximum deck accelerations, maximum load effects, etc.) are satisfactory for structures at speeds in excess of 200 km/h. Fatigue and passenger comfort criteria need not be checked at 1,2 × Maximum Train Commissioning Speeds.

  2. Calculations should be made for a series of speeds from 40m/s up to the Maximum Design Speed defined by 6.4.6.2(1). Smaller speed steps should be made in the vicinity of Resonant Speeds.

    For simply supported bridges that may be modelled as a line beam the Resonant Speeds may be estimated using Equation 6.9.

    vi = n0 λi     (6.9)

    87

    and

    40 m/s ≤ vi ≤ Maximum Design Speed,     (6.10)

    where:

    vi is the Resonant Speed [m/sec]
    n0 is the first natural frequency of the unloaded structure,
    λi is the principal wavelength of frequency of excitation and may be estimated by:
    Image
    d is the regular spacing of groups of axles
    i = 1, 2, 3 or 4.
6.4.6.3 Bridge parameters
6.4.6.3.1 Structural damping
  1. The peak response of a structure at traffic speeds corresponding to resonant loading is highly dependent upon damping.
  2. P Only lower bound estimates of damping shall be used.
  3. The following values of damping should be used in the dynamic analysis:
Table 6.6 - Values of damping to be assumed for design purposes
Bridge Type ζ Lower limit of percentage of critical damping [%]
Span L < 20m Span L ≥ 20m
Steel and composite ζ = 0,5 + 0,125 (20 - L) ζ = 0,5
Prestressed concrete ζ = 1,0 + 0,07 (20 - L) ζ = 1,0
Filler beam and reinforced concrete ζ = 1,5 + 0,07 (20 - L) ζ = 1,5

NOTE Alternative safe lower bound values may be used subject to the agreement of the relevant authority specified in the National Annex.

6.4.6.3.2 Mass of the bridge
  1. Maximum dynamic load effects are likely to occur at resonant peaks when a multiple of the frequency of loading and a natural frequency of the structure coincide and any underestimation of mass will overestimate the natural frequency of the structure and overestimate the traffic speeds at which resonance occurs.

    At resonance the maximum acceleration of a structure is inversely proportional to the mass of the structure.

  2. P Two specific cases for the mass of the structure including ballast and track shall be considered: 88

    NOTE The minimum density of ballast may be taken as 1700kg/ m3. Alternative values may be specified for the individual project.

  3. In the absence of specific test data the values for the density of materials should be taken from EN 1991-1-1.

NOTE Owing to the large number of parameters which can affect the density of concrete it is not possible to predict enhanced density values with sufficient accuracy for predicting the dynamic response of a bridge. Alternative density values may be used when the results are confirmed by trial mixes and the testing of samples taken from site in accordance with EN 1990, EN 1992 and ISO 6784 subject to the agreement of the relevant authority specified in the National Annex.

6.4.6.3.3 Stiffness of the bridge
  1. Maximum dynamic load effects are likely to occur at resonant peaks when a multiple of the frequency of loading and a natural frequency of the structure coincide. Any overestimation of bridge stiffness will overestimate the natural frequency of the structure and speed at which resonance occurs.
  2. P A lower bound estimate of the stiffness throughout the structure shall be used.
  3. The stiffness of the whole structure including the determination of the stiffness of elements of the structure may be determined in accordance with EN 1992 to EN 1994.

Values of Young’s modulus may be taken from EN 1992 to EN 1994.

For concrete compressive cylinder strength fck ≥ 50 N/mm2 (compressive cube strength fck, cube ≥ 60 N/mm2) the value of static Young’s modulus (Ecm) should be limited to the value corresponding to a concrete of strength of fck = 50 N/mm2 (fck, cube = 60 N/mm2).

NOTE 1 Owing to the large number of parameters which can affect Ecm it is not possible to predict enhanced Young’s modulus values with sufficient accuracy for predicting the dynamic response of a bridge. Enhanced Ecm values may be used when the results are confirmed by trial mixes and the testing of samples taken from site in accordance with EN 1990, EN 1992 and ISO 6784 subject to the agreement of the relevant authority specified in the National Annex.

NOTE 2 Other material properties may be used subject to the agreement of the relevant authority specified in the National Annex.

6.4.6.4 Modelling the excitation and dynamic behaviour of the structure
  1. The dynamic effects of a Real Train may be represented by a series of travelling point forces. Vehicle/structure mass interaction effects may be neglected.

    The analysis should take into account variations throughout the length of the train in axle forces and the variations in spacing of individual axles or groups of axles.

    89
  2. Where appropriate the analysis technique should allow for the following dynamic behaviours of the structure:
  3. The representation of each axle by a single point force tends to overestimate dynamic effects for loaded lengths of less than 10m. In such cases, the load distribution effects of rails, sleepers and ballast may be taken into account.

    Notwithstanding 6.3.6.2(1) individual axle loads should not be distributed uniformly in the longitudinal direction for a dynamic analysis.

  4. For spans less than 30 m dynamic vehicle/bridge mass interaction effects tend to reduce the peak response at resonance. Account may be taken of these effects by:

    NOTE The method used should be agreed with the relevant authority specified in the National Annex.

  5. The increase in calculated dynamic load effects (stresses, deflections, bridge deck accelerations, etc.) due to track defects and vehicle imperfections may be estimated by multiplying the calculated effects by a factor of:
    (1 + φ″/2) for carefully maintained track,
    (1 + φ″) for track with standard track maintenance,

    where:

    φ is in accordance with annex C and should not be taken as less than zero.

    NOTE The National Annex may specify the factor to be used.

  6. Where the bridge satisfies the upper limit in Figure 6.10 the factors that influence dynamic behaviours (vii) to (xi) identified in 6.4.2 may be considered to be allowed for in Φ, φ″/2 and φ″ given in 6.4 and annex C.
6.4.6.5 Verifications of the limit states
  1. P To ensure traffic safety:
  2. P The maximum permitted peak design values of bridge deck acceleration calculated along the line of a track shall not exceed the recommended values given in A2 of EN 1990 (see A2.4.4.2.1).
  3. A dynamic analysis (if required) should be used to determine the following dynamic enhancement:

    φdyn= max | ydyn / ystat | – 1     (6.14)

    where:

    91
    ydyn is the maximum dynamic response and Image text deleted Image
    Image ystat the corresponding maximum static response at any particular point in the structural element due to a Real Train or Load Model HSLM.Image

    For the design of the bridge, taking into account all the effects of vertical traffic loads, the most unfavourable value of:

    Image

    or

    Φ × (LM71”+”SW/0)     (6.16)

    should be used where:

    HSLM is the load model for high speed lines defined in 6.4.6.1.1(2),
    LM71”+”SW/0 is Load Model 71 and if relevant Load Model SW/0 for continuous bridges (or classified vertical load in accordance with 6.3.2(3) where required).
    RT is the loading due to all Real Trains defined in 6.4.6.1.1.
    φ″/2 is the increase in calculated dynamic load effects (stresses, deflections, bridge deck accelerations, etc.) resulting from track defects and vehicle imperfections in accordance with annex C for carefully maintained track (φ″ to be used for track with standard maintenance).
    Φ is the dynamic factor in accordance with 6.4.5.
6.4.6.6 Additional verification for fatigue where dynamic analysis is required
  1. P The fatigue check of the structure shall allow for the stress range resulting from elements of the structure oscillating above and below the corresponding permanent load deflection due to:
  2. P Where the Frequent Operating Speed of a Real Train at a structure is near to a Resonant Speed the design shall allow for the additional fatigue loading due to resonance effects.

    NOTE The individual project may specify the fatigue loading, e.g. details, annual tonnage and mix of Real Trains and associated Frequent Operating Speeds at the site to be taken into account in the design.

  3. Where the bridge is designed for Load Model HSLM in accordance with 6.4.6.1.1(2) the fatigue loading should be specified taking into account the best estimate of current and future traffic.

    NOTE The individual project may specify the fatigue loading e.g. details, annual tonnage and mix of Real Trains and associated Frequent Operating Speeds at the site to be taken into account in the design.

    92
  4. For structures that satisfy annex F the Resonant Speed may be estimated using equations 6.9 and 6.10.
  5. For the verification for fatigue a series of speeds up to a Maximum Nominal Speed should be considered.

    NOTE It is recommended that the individual project specify an increased Maximum Nominal Speed at the Site to take into account potential modifications to the infrastructure and future rolling stock.

6.5 Horizontal forces - characteristic values

6.5.1 Centrifugal forces

  1. P Where the track on a bridge is curved over the whole or part of the length of the bridge, the centrifugal force and the track cant shall be taken into account.
  2. The centrifugal forces should be taken to act outwards in a horizontal direction at a height of 1,80 m above the running surface (see Figure 1.1). For some traffic types, e.g. double stacked containers, an increased value of ht should be specified.

    NOTE The National Annex or individual project may specify an increased value of ht.

  3. P The centrifugal force shall always be combined with the vertical traffic load. The centrifugal force shall not be multiplied by the dynamic factor Φ2 or Φ3.

    NOTE When considering the vertical effects of centrifugal loading, the vertical load effect of centrifugal loading less any reduction due to cant is enhanced by the relevant dynamic factor.

  4. P The characteristic value of the centrifugal force shall be determined according to the following equation:

    Image

    Image

    where:

    Qtk, qtk Characteristic values of the centrifugal forces [kN, kN/m]
    Qvk, qvk Characteristic values of the vertical loads specified in 6.3 (excluding any enhancement for dynamic effects) for Load Models 71, SW/0, SW/2 and “unloaded train”. For load model HSLM the characteristic value of centrifugal force should be determined using Load Model 71.
    f Reduction factor (see below)
    v Maximum speed in accordance with 6.5.1(5) [m/s]
    V Maximum speed in accordance with 6.5.1(5) [km/h]
    g Acceleration due to gravity [9,81 m/s2]
    r Radius of curvature [m]

    In the case of a curve of varying radii, suitable mean values may be taken for the value r.

    93
  5. P The calculations shall be based on the specified Maximum Line Speed at the Site. In the case of Load Model SW/2 an alternative maximum speed may be assumed.

    NOTE l The individual project may specify the requirements.

    NOTE 2 For SW/2 a maximum speed of 80km/h may be used.

    NOTE 3 It is recommended that the individual project specify an increased Maximum Line Speed at the Site to take into account potential modifications to the infrastructure and future rolling stock.

  6. P In addition, for bridges located in a curve, the case of the loading specified in 6.3.2 and, if applicable, 6.3.3, shall also be considered without centrifugal force.
  7. For Load Model 71 (and where required Load Model SW/0) and a Maximum Line Speed at the Site higher than 120 km/h, the following cases should be considered:
    1. Load Model 71 (and where required Load Model SW/0) with its dynamic factor and the centrifugal force for V=120 km/h according to equations 6.17 and 6.18 with f = 1.
    2. b) Load Model 71 (and where required Load Model SW/0) with its dynamic factor and the centrifugal force according to equations 6.17 and 6.18 for the maximum speed V specified, with a value for the reduction factor f given by 6.5.1(8).
  8. For Load Model 71 (and where required Load Model SW/0) the reduction factor f is given by:

    Image

    subject to a minimum value of 0,35 where:

    Lf is the influence length of the loaded part of curved track on the bridge, which is most unfavourable for the design of the structural element under consideration [m].
    V is the maximum speed in accordance with 6.5.1(5).
    f = 1 for either V ≤ 120 km/h    or Lf ≤ 2,88 m  
    f < 1 for 120 km/h <V ≤ 300 km/h )  
      (see Table 6.7 or Figure 6.16 or equation 6.19) ) and Lf > 2,88m
    f(v) = f(300) for V >300 km/h. )  

    For the load models SW/2 and “unloaded train” the value of the reduction factor f should be taken as 1,0.

    94
    Table 6.7 - Factor f for Load Model 71 and SW/0
    Lf[m] Maximum speed in accordance with 6.5.1 [km/h]
    ≤ 120 160 200 250 ≥ 300
    ≤ 2,88 1,00 1,00 1,00 1,00 1,00
    3 1,00 0,99 0,99 0,99 0,98
    4 1,00 0,96 0,93 0,90 0,88
    5 1,00 0,93 0,89 0,84 0,81
    6 1,00 0,92 0,86 0,80 0,75
    7 1,00 0,90 0,83 0,77 0,71
    8 1,00 0,89 0,81 0,74 0,68
    9 1,00 0,88 0,80 0,72 0,65
    10 1,00 0,87 0,78 0,70 0,63
    12 1,00 0,86 0,76 0,67 0,59
    15 1,00 0,85 0,74 0,63 0,55
    20 1,00 0,83 0,71 0,60 0,50
    30 1,00 0,81 0,68 0,55 0,45
    40 1,00 0,80 0,66 0,52 0,41
    50 1,00 0,79 0,65 0,50 0,39
    60 1,00 0,79 0,64 0,49 0,37
    70 1,00 0,78 0,63 0,48 0,36
    80 1,00 0,78 0,62 0,47 0,35
    90 1,00 0,78 0,62 0,47 0,35
    100 1,00 0,77 0,61 0,46 0,35
    ≥150 1,00 0,76 0,60 0,44 0,35
    Figure 6.16 - Factor f for Load Model 71 and SW/0

    Figure 6.16 - Factor f for Load Model 71 and SW/0

    95
  9. For LM71 and SW/0 centrifugal forces should be determined from equations 6.17 and 6.18 using classified vertical loads (see 6.3.2(3)) in accordance with the load cases given in Table 6.8:
    Table 6.8 - Load Cases for centrifugal force corresponding to values of α and Maximum Line Speed at Site
    Value of α Maximum Line Speed at Site [km/h] Centrifugal force based on : d Associated vertical traffic action based
    on: a
    V
    [km/h]
    α f  
    α < 1 > 120 V 1c f 1c × f × (LM71”+“SW/0) for case 6.5.1(7)b Φ × α × 1 × (LM71”+“SW/0)
    120 α 1 α × 1 × (LM71”+“SW/0) for case 6.5.1(7)a Φ × α × 1 × (LM71”+“SW/0)
    0 - - -
    ≤ 120 V α 1 α × 1 × (LM71”+“SW/0)
    0 - - -
    α = 1 > 120 V 1 f 1 × f × (LM71”+“SW/0) for case 6.5.1(7)b Φ × 1 × 1 × (LM71”+“SW/0)
    120 1 1 1 × 1 × (LM71”+“SW/0) for case 6.5.1(7)a Φ × 1 × 1 × (LM71”+“SW/0)
    0 - - -
    ≤ 120 V 1 1 1 × 1 × (LM71”+“"SW/0)
    0 - - -
    α > 1 > 120 b V 1 f 1 × f × (LM71”+“SW/0) for case 6.5.1(7)b Φ × 1 × 1 × (LM71”+“SW/0)
    120 α 1 α 1 × (LM71”+“SW/0) for case 6.5.1(7)a Φ × α × 1 × (LM71”+“SW/0)
    0 - - -
    ≤ 120 V α 1 α × 1 × (LM71”+“SW/0)
    0 - - -
    1. 0,5 × (LM71”+“SW/0) instead of (LM71”+“SW/0) where vertical traffic actions favourable.
    2. Valid for heavy freight traffic limited to a maximum speed of 120 km/h.
    3. α = 1 to avoid double counting the reduction in mass of train with f.
    4. See 6.5.1(3) regarding vertical effects of centrifugal loading. Vertical load effect of centrifugal loading less any reduction due to cant should be enhanced by the relevant dynamic factor. When determining the vertical effect of centrifugal force, factor f to be included as shown above.

    where:

    96
    V Maximum speed in accordance with 6.5.1(5) [km/h]
    f Reduction factor in accordance with 6.5.1(8)
    α Factor for classified vertical loads in accordance with 6.3.2(3).
    LM71”+“SW/0 Load Model 71 and if relevant Load Model SW/0 for continuous bridges.
  10. The criteria in 6.5.1(5) and 6.5.1(7) to 6.5.1(9) are not valid for heavy freight traffic with a Maximum Permitted Vehicle Speed exceeding 120 km/h. For heavy freight traffic with a speed exceeding 120 km/h additional requirements should be specified.

    NOTE The individual project may specify the additional requirements.

6.5.2 Nosing force

  1. P The nosing force shall be taken as a concentrated force acting horizontally, at the top of the rails, perpendicular to the centre-line of track. It shall be applied on both straight track and curved track.
  2. P The characteristic value of the nosing force shall be taken as Qsk = 100 kN. It shall not be multiplied by the factor Φ (see 6.4.5) or by the factor/in 6.5.1(4).
  3. The characteristic value of the nosing force in 6.5.2(2) should be multiplied by the factor α in accordance with 6.3.2(3) for values of α ≥ 1.
  4. P The nosing force shall always be combined with a vertical traffic load.

6.5.3 Actions due to traction and braking

  1. P Traction and braking forces act at the top of the rails in the longitudinal direction of the track. They shall be considered as uniformly distributed over the corresponding influence length La,b for traction and braking effects for the structural element considered. The direction of the traction and braking forces shall take account of the permitted direction(s) of travel on each track.
  2. P The characteristic values of traction and braking forces shall be taken as follows:
    Traction force: Qlak = 33 [kN/m] La,b [m] ≤ 1000 [kN] for Load Models 71, SW/0, SW/2 and HSLM (6.20)
    Braking force: Qlbk = 20 [kN/m] La,b [m] ≤ 6000 [kN] for Load Models 71, SW/0 and Load Model HSLM (6.21)
      Qlbk = 35 [kN/m] La,b [m] for Load Model SW/2 (6.22)

    The characteristic values of traction and braking forces shall not be multiplied by the factor Φ (see 6.4.5.2) or by the factor/in 6.5.1(6).

    97

    NOTE l For Load Models SW/0 and SW/2 traction and braking forces need only to be applied to those parts of the structure which are loaded according to Figure 6.2 and Table 6.1.

    NOTE 2 Traction and braking may be neglected for the Load Model “unloaded train”.

  3. These characteristic values are applicable to all types of track construction, e.g. continuous welded rails or jointed rails, with or without expansion devices.
  4. The above traction and braking forces for Load Models 71 and SW/0 should be multiplied by the factor α in accordance with the requirements of 6.3.2(3).
  5. For loaded lengths greater than 300m additional requirements for taking into account the effects of braking should be specified.

    NOTE The National Annex or individual project may specify the additional requirements.

  6. For lines carrying special traffic (e.g. restricted to high speed passenger traffic) the traction and braking forces may be taken as equal to 25% of the sum of the axle-loads (Real Train) acting on the influence length of the action effect of the structural element considered, with a maximum value of 1000 kN for Qlak and 6000 kN for Qlbk. The lines carrying special traffic and associated loading details may be specified.

    NOTE 1 The individual project may specify the requirements.

    NOTE 2 Where the individual project specifies reduced traction and braking loading in accordance with the above the specified loading should take into account other traffic permitted to use the line, e.g. trains for track maintenance etc.

  7. P Traction and braking forces shall be combined with the corresponding vertical loads.
  8. When the track is continuous at one or both ends of the bridge only a proportion of the traction or braking force is transferred through the deck to the bearings, the remainder of the force being transmitted through the track where it is resisted behind the abutments. The proportion of the force transferred through the deck to the bearings should be determined by taking into account the combined response of the structure and track in accordance with 6.5.4.
  9. P In the case of a bridge carrying two or more tracks the braking forces on one track shall be considered with the traction forces on one other track.
    Where two or more tracks have the same permitted direction of travel either traction on two tracks or braking on two tracks shall be taken into account.

    NOTE For bridges carrying two or more tracks with the same permitted direction of travel the National Annex may specify alternative requirements for the application of traction and braking forces.

6.5.4 Combined response of structure and track to variable actions

6.5.4.1 General principles
  1. Where the rails are continuous over discontinuities in the support to the track (e.g. between a bridge structure and an embankment) the structure of the bridge (bridge deck, bearings and substructure) and the track (rails, ballast etc.) jointly resist the longitudinal 98 actions due to traction or braking. Longitudinal actions are transmitted partly by the rails to the embankment behind the abutment and partly by the bridge bearings and the substructure to the foundations.

    NOTE References to embankment throughout 6.5.4 may also be taken as references to the track formation or ground beneath the track on the approaches to the bridge whether the track is on an embankment, level ground or in a cutting.

  2. Where continuous rails restrain the free movement of the bridge deck, deformations of the bridge deck (e.g. due to thermal variations, vertical loading, creep and shrinkage) produce longitudinal forces in the rails and in the fixed bridge bearings.
  3. P The effects resulting from the combined response of the structure and the track to variable actions shall be taken into account for the design of the bridge superstructure, fixed bearings, the substructure and for checking load effects in the rails.
  4. The requirements of 6.5.4 are valid for conventional ballasted track.
  5. The requirements for non-ballasted track should be specified.

    NOTE The requirements for non-ballasted track may be specified in either the National Annex or for the individual project.

6.5.4.2 Parameters affecting the combined response of the structure and track
  1. P The following parameters influence the combined behaviour of the structure and track and shall be taken into account in the analysis:
    1. Configuration of the structure:
      • – simply supported beam, continuous beams or a series of beams,
      • – number of individual decks and length of each deck,
      • – number of spans and length of each span,
      • – position of fixed bearings,
      • – position of the thermal fixed point,
      • – expansion length LT between the thermal fixed point and the end of the deck.

      Figure 6.17 - Examples of expansion length LT

      Figure 6.17 - Examples of expansion length LT

      99
    2. Configuration of the track:
      • – ballasted track or non-ballasted track systems,
      • – vertical distance between the upper surface of the deck and the neutral axis of the rails,
      • – location of rail expansion devices.

      NOTE The individual project may specify requirements regarding the location of rail expansion devices taking into account requirements to ensure such devices are effective whilst ensuring that the rail expansion devices are not adversely affected by bending effects in the rail due to the close proximity of the end of a bridge deck etc.

    3. Properties of the structure:
      • – vertical stiffness of the deck,
      • – vertical distance between the neutral axis of the deck and the upper surface of the deck,
      • – vertical distance between the neutral axis of the deck and the axis of rotation of the bearing,
      • – structural configuration at bearings generating longitudinal displacement of the end of the deck from angular rotation of the deck,
      • – longitudinal stiffness of the structure defined as the total stiffness which can be mobilised by the substructure against actions in the longitudinal direction of the tracks taking into account the stiffness of the bearings, substructure and foundations.

      For example the total longitudinal stiffness of a single pier is given by:

      Image

      for the case represented below as an example.

      100

      Figure 6.18 - Example of the determination of equivalent longitudinal stiffness at bearings

      Figure 6.18 - Example of the determination of equivalent longitudinal stiffness at bearings

    4. Properties of the track:
      • – axial stiffness of the rail,
      • – resistance of the track or the rails against longitudinal displacement considering either:
        • – resistance against displacement of the track (rails and sleepers) in the ballast relative to the underside of the ballast, or
        • – resistance against displacement of the rails from rail fastenings and supports e.g. with frozen ballast or with directly fastened rails,

          where the resistance against displacement is the force per unit length of the track that acts against the displacement as a function of the relative displacement between rail and the supporting deck or embankment.

6.5.4.3 Actions to be considered
  1. P The following actions shall be taken into account:

    NOTE The combined response of the structure and track to the “unloaded train” and load model HSLM may be neglected.

  2. Temperature variations in the bridge should be taken as ΔTN (see EN 1991-1-5), with γ and ψ taken as 1,0.

    NOTE 1 The National Annex may specify alternative values of ΔTN. The values given in EN 1991-1-5 are recommended.

    NOTE 2 For simplified calculations a temperature variation of the superstructure of ΔTN = ± 35 Kelvin may be taken into account. Other values may be specified in the National Annex or for the individual project.

  3. When determining the combined response of track and structure to traction and braking forces, the traction and braking forces should not be applied on the adjacent embankment unless a complete analysis is carried out considering the approach, passage over and departure from the bridge of rail traffic on the adjacent embankments to evaluate the most adverse load effects.
6.5.4.4 Modelling and calculation of the combined track/structure system
  1. For the determination of load effects in the combined track/structure system a model based upon Figure 6.19 may be used.

    Figure 6.19 - Example of a model of a track/structure system

    Figure 6.19 - Example of a model of a track/structure system

  2. The longitudinal load/ displacement behaviour of the track or rail supports may be represented by the relationship shown in Figure 6.20 with an initial elastic shear resistance [kN/mm of displacement per m of track] and then a plastic shear resistance k [kN/m of track]. 102

    Figure 6.20 - Variation of longitudinal shear force with longitudinal track displacement for one track

    Figure 6.20 - Variation of longitudinal shear force with longitudinal track displacement for one track

    NOTE 1 The values of longitudinal resistance used for the analysis of rail/ballast/bridge stiffness may be given in the National Annex or agreed with the relevant authority specified in the National Annex.

    NOTE 2 The behaviour described in Figure 6.20 is valid in most cases (but not for embedded rails without conventional rail fastenings etc.).

  3. P Where it can be reasonably foreseen that the track characteristics may change in the future, this shall be taken into account in the calculations in accordance with the specified requirements.

    NOTE The individual project may specify the requirements.

  4. P For the calculation of the total longitudinal support reaction FL and in order to compare the global equivalent rail stress with permissible values, the global Image effect shall be calculated Image as follows:

    Image

    with:

    F1i the individual longitudinal support reaction corresponding to the action i,
    ψ0i for the calculation of load effects in the superstructure, bearings and substructures the combination factors defined in EN 1990 A2 shall be used,
    ψ0i for the calculation of rail stresses, ψ0i shall be taken as 1,0.
    103
  5. When determining the effect of each action the non-linear behaviour of the track stiffness shown in Figure 6.20 should be taken into account.
  6. The longitudinal forces in the rails and bearings resulting from each action may be combined using linear superimposition.
6.5.4.5 Design criteria

NOTE Alternative requirements may be specified in the National Annex.

6.5.4.5.1 Track
  1. For rails on the bridge and on the adjacent abutment the permissible additional rail stresses due to the combined response of the structure and track to variable actions should be limited to the following design values:
    Compression: 72 N/mm2,
    Tension: 92 N/mm2.
  2. The limiting values for the rail stresses given in 6.5.4.5.1(1) are valid for track complying with:

    When the above criteria are not satisfied special studies should be carried out or additional measures provided.

    NOTE For other track construction standards (in particular those that affect lateral resistance) and other types of rail it is recommended that the maximum additional rail stresses is specified in the National Annex or for the individual project.

6.5.4.5.2 Limiting values for the deformation of the structure
  1. P Due to traction and braking δB [mm] shall not exceed the following values:

    where δB [mm] is:

    104
  2. P For vertical traffic actions (up to two tracks loaded with load model LM 71 (and where required SW/0) δH [mm] shall not exceed the following values:

    where δH [mm] is:

    NOTE Where either the permissible additional stresses in the rail in 6.5.4.5.1(1) are exceeded or the longitudinal displacement of the deck in 6.5.4.5.2(1) or 6.5.4.5.2(2) is exceeded either change the structure or provide rail expansion devices.

  3. P The vertical displacement of the upper surface of a deck relative to the adjacent construction (abutment or another deck) δv [mm] due to variable actions shall not exceed the following values:
  4. P For directly fastened rails the uplift forces (under vertical traffic loads) on rail supports and fastening systems shall be checked against the relevant limit state (including fatigue) performance characteristics of the rail supports and fastening systems.
6.5.4.6 Calculation methods

NOTE Alternative calculation methods may be specified in the National Annex or for the individual project.

  1. The following calculation methods enable the combined response of the track and structure to be checked against the design criteria given in 6.5.4.5. The design criteria for ballasted decks may be summarised as:
    1. Longitudinal relative displacement at the end of the deck split into two components to enable comparison with the permitted values: δB due to braking and traction and δH due to vertical deformation of the deck,
    2. Maximum additional stresses in the rails,
    3. Maximum vertical relative displacement at the end of the deck, δv.

    For directly fastened decks an additional check on uplift forces is required in accordance with 6.5.4.5.2(4).

  2. In 6.5.4.6.1 a simplified method is given for estimating the combined response of a simply supported or a continuous structure consisting of single bridge deck and track to variable actions for structures with an expansion length LT of up to 40m. 105
  3. For structures that do not satisfy the requirements of 6.5.4.6.1 a method is given in annex G for determining the combined response of a structure and track to variable actions for:
  4. Alternatively, or for other track or structural configurations, an analysis may be carried out in accordance with the requirements of 6.5.4.2 to 6.5.4.5.
6.5.4.6.1 Simplified calculation method for a single deck
  1. For a superstructure comprising of a single deck (simply supported, continuous spans with a fixed bearing at one end or continuous spans with an intermediate fixed bearing) it is not necessary to check the rail stresses providing:

    NOTE Alternative criteria may be specified in the National Annex. The criteria given in this clause are recommended.

  2. The limits of validity of the calculation method in 6.5.4.6.1 are:
  3. The longitudinal forces due to traction and braking acting on the fixed bearings may be obtained by multiplying the traction and braking forces by the reduction factor ξ given in Table 6.9.
    Table 6.9 - Reduction factor ξ for the determination of the longitudinal forces in the fixed bearings of one-piece decks due to traction and braking
    Overall length of structure [m] Reduction factor ξ
    Continuous track Rail expansion devices at one end of deck Rail expansion devices at both ends of deck
    ≤ 40 0,60 0,70 1,00

    NOTE For portal frames and closed frames or boxes it is recommended that the reduction factor ξ be taken as unity. Alternatively the method given in annex G or an analysis in accordance with 6.5.4.2 to 6.5.4.5 may be used.

  4. The characteristic longitudinal forces FTk per track due to temperature variation (according to 6.5.4.3) acting on the fixed bearings may be obtained as follows :
  5. The characteristic longitudinal forces FQk per track on the fixed bearings due to deformation of the deck may be obtained as follows:
  6. The vertical displacement of the upper surface of a deck relative to the adjacent construction (abutment or another deck) due to variable actions may be calculated ignoring the combined response of the structure and track and checked against the criteria in 6.5.4.5.2(3).

6.6 Aerodynamic actions from passing trains

6.6.1 General

  1. P Aerodynamic actions from passing trains shall be taken into account when designing structures adjacent to railway tracks.
  2. The passing of rail traffic subjects any structure situated near the track to a travelling wave of alternating pressure and suction (see Figures 6.22 to 6.25). The magnitude of the action depends mainly on:
  3. The actions may be approximated by equivalent loads at the head and rear ends of a train, when checking ultimate and serviceability limit states and fatigue. Characteristic values of the equivalent loads are given in 6.6.2 to 6.6.6.

    NOTE The National Annex or the individual project may specify alternative values. The values given in 6.6.2 to 6.6.6. are recommended.

  4. In 6.6.2 to 6.6.6 the Maximum Design Speed V [km/h] should be taken as the Maximum Line Speed at the Site except for cases covered by EN 1990 A2.2.4(6). 108
  5. At the start and end of structures adjacent to the tracks, for a length of 5 m from the start and end of the structure measured parallel to the tracks the equivalent loads in 6.6.2 to 6.6.6 should be multiplied by a dynamic amplification factor of 2,0.

    NOTE For dynamically sensitive structures the above dynamic amplification factor may be insufficient and may need to be determined by a special study. The study should take into account dynamic characteristics of the structure including support and end conditions, the speed of the adjacent rail traffic and associated aerodynamic actions and the dynamic response of the structure including the speed of a deflection wave induced in the structure. In addition, for dynamically sensitive structures a dynamic amplification factor may be necessary for parts of the structure between the start and end of the structure.

6.6.2 Simple vertical surfaces parallel to the track (e.g. noise barriers)

  1. The characteristic values of the actions, ± q1k, are given in Figure 6.22.

    Figure 6.22 - Characteristic values of actions qlk for simple vertical surfaces parallel to the track

    Figure 6.22 - Characteristic values of actions qlk for simple vertical surfaces parallel to the track

  2. The characteristic values apply to trains with an unfavourable aerodynamic shape and may be reduced by:
  3. If a small part of a wall with a height ≤ 1,00 m and a length ≤ 2,50 m is considered, e.g. an element of a noise protection wall, the actions q1k should be increased by a factor k2= 1,3.

6.6.3 Simple horizontal surfaces above the track (e.g. overhead protective structures)

  1. The characteristic values of the actions, ± q2k, are given in Figure 6.23.
  2. The loaded width for the structural member under investigation extends up to 10 m to either side from the centre-line of the track.

    Figure 6.23 - Characteristic values of actions q2k for simple horizontal surfaces above the track

    Figure 6.23 - Characteristic values of actions q2k for simple horizontal surfaces above the track

  3. For trains passing each other in opposite directions the actions should be added. The loading from trains on only two tracks needs to be considered.
  4. The actions q2k may be reduced by the factor k1 as defined in 6.6.2. 110
  5. The actions acting on the edge strips of a wide structure which cross the track may be multiplied by a factor of 0,75 over a width up to 1,50 m.

6.6.4 Simple horizontal surfaces adjacent to the track (e.g. platform canopies with no vertical wall)

  1. The characteristic values of the actions, ± q3k, are given in Figure 6.24 and apply irrespective of the aerodynamic shape of the train.
  2. For every position along the structure to be designed, q3k should be determined as a function of the distance ag from the nearest track. The actions should be added, if there are tracks on either side of the structural member under consideration.
  3. If the distance hg exceeds 3,80 m the action q3k may be reduced by a factor k3.

    Image

    k3 = 0     for hg ≥ 7,5 m     (6.33)

    where:

    hg     distance from top of rail level to the underside of the structure.

    Figure 6.24 - Characteristic values of actions q3k for simple horizontal surfaces adjacent to the track

    Figure 6.24 - Characteristic values of actions q3k for simple horizontal surfaces adjacent to the track

111

6.6.5 Multiple-surface structures alongside the track with vertical and horizontal or inclined surfaces (e.g. bent noise barriers, platform canopies with vertical walls etc.)

  1. The characteristic values of the actions, ± q4k, as given in Figure 6.25 should be applied normal to the surfaces considered. The actions should be taken from the graphs in Figure 6.22 adopting a track distance the lesser of:

    ag = 0,6 min ag + 0,4 max ag     or     6 m     (6.34)

    where distances min ag and max ag are shown in Figure 6.25.

  2. If max ag > 6 m the value max ag = 6 m should be used.
  3. The factors k1 and k2 defined in 6.6.2 should be used.

    Figure 6.25 - Definition of the distances min ag and max ag from centre-line of the track

    Figure 6.25 - Definition of the distances min ag and max ag from centre-line of the track

6.6.6 Surfaces enclosing the structure gauge of the tracks over a limited length (up to 20 m) (horizontal surface above the tracks and at least one vertical wall, e.g. scaffolding, temporary constructions)

  1. All actions should be applied irrespective of the aerodynamic shape of the train:

    ±k4q1k     (6.35)

    where:

    q1k is determined according to 6.6.2,
    k4 = 2

    112

    ±k5q2k     (6.36)

    where:

    q2k is determined according to 6.6.3 for only one track,

    k5 = 2,5 if one track is enclosed,

    k5 = 3,5 if two tracks are enclosed.

6.7 Derailment and other actions for railway bridges

  1. P Railway structures shall be designed in such a way that, in the event of a derailment, the resulting damage to the bridge (in particular overturning or the collapse of the structure as a whole) is limited to a minimum.

6.7.1 Derailment actions from rail traffic on a railway bridge

  1. P Derailment of rail traffic on a railway bridge shall be considered as an Accidental Design Situation.
  2. P Two design situations shall be considered:

    NOTE The National Annex or individual project may specify additional requirements and alternative loading.

  3. P For Design Situation I, collapse of a major part of the structure shall be avoided. Local damage, however, may be tolerated. The parts of the structure concerned shall be designed for the following design loads in the Accidental Design Situation:

    α × 1,4 × LM 71 (both point loads and uniformly distributed loading, QA1d and qA1d) parallel to the track in the most unfavourable position inside an area of width 1,5 times the track gauge on either side of the centre-line of the track:

    113

    Figure 6.26 - Design Situation I - equivalent load <2aici and qAld

    Figure 6.26 - Design Situation I - equivalent load QA1d and qAld

  4. P For Design Situation II, the bridge should not overturn or collapse. For the determination of overall stability a maximum total length of 20 m of qA2d = α × 1,4 × LM71 shall be taken as a uniformly distributed vertical line load acting on the edge of the structure under consideration.

    Figure 6.27 - Design Situation II - equivalent load qA2d

    Figure 6.27 - Design Situation II - equivalent load qA2d

    NOTE The above-mentioned equivalent load is only to be considered for determining the ultimate strength or the stability of the structure as a whole. Minor structural elements need not be designed for this load.

  5. P Design Situations I and II shall be examined separately. A combination of these loads need not be considered. 114
  6. For Design Situations I and II other rail traffic actions should be neglected for the track subjected to derailment actions.

    NOTE See EN 1990 A2 for the requirements for application of traffic actions to other tracks.

  7. No dynamic factor needs to be applied to the design loads in 6.7.1(3) and 6.7.1(4).
  8. P For structural elements which are situated above the level of the rails, measures to mitigate the consequences of a derailment shall be in accordance with the specified requirements.

    NOTE 1 The requirements may be specified in the National Annex or for the individual project.

    NOTE 2 The National Annex or individual project may also specify requirements to retain a derailed train on the structure.

6.7.2 Derailment under or adjacent to a structure and other actions for Accidental Design Situations

  1. When a derailment occurs, there is a risk of collision between derailed vehicles and structures over or adjacent to the track. The requirements for collision loading and other design requirements are specified in EN 1991-1-7.
  2. Other actions for Accidental Design Situations are given in EN 1991-1-7 and should be taken into account.

6.7.3 Other actions

  1. P The following actions shall also be taken into account in the design of the structure:

    NOTE The specified requirements including actions for any Accidental Design Situation to be taken into account may be specified in the National Annex or for the individual project.

6.8 Application of traffic loads on railway bridges

6.8.1 General

NOTE See 6.3.2 for the application of the factor α and 6.4.5 for the application of the dynamic factor Φ.

  1. P The structure shall be designed for the required number and position(s) of the tracks in accordance with the track positions and tolerances specified. 115

    NOTE The track positions and tolerances may be specified for the individual project.

  2. Each structure should also be designed for the greatest number of tracks geometrically and structurally possible in the least favourable position, irrespective of the position of the intended tracks taking into account the minimum spacing of tracks and structural gauge clearance requirements specified.

    NOTE The minimum spacing of tracks and structural gauge clearance requirements may be specified for the individual project.

  3. P The effects of all actions shall be determined with the traffic loads and forces placed in the most unfavourable positions. Traffic actions which produce a relieving effect shall be neglected.
  4. P For the determination of the most adverse load effects from the application of Load Model 71:
  5. P For the determination of the most adverse load effects from the application of Load Model SW/0:
  6. P For the determination of the most adverse load effects from the application of Load Model SW/2:
  7. P For the determination of the most adverse load effects from the application of Load Model “unloaded train”:
  8. P All continuous beam structures designed for Load Model 71 shall be checked additionally for Load Model SW/0. 116
  9. P Where a dynamic analysis is required in accordance with 6.4.4 all bridges shall also be designed for the loading from Real trains and Load Model HSLM where required by 6.4.6.1.1. The determination of the most adverse load effects from Real Trains and the application of Load Model HSLM shall be in accordance with 6.4.6.1.1(6) and 6.4.6.5(3).
  10. P For the verification of deformations and vibrations the vertical loading to be applied shall be:
  11. P For bridge decks carrying one or more tracks the checks for the limits of deflection and vibration shall be made with the number of tracks loaded with all associated relevant traffic actions in accordance with Table 6.10. Where required by 6.3.2(3) classified loads shall be taken into account.
117
Table 6.10 - Number of tracks to be loaded for checking limits of deflection and vibration
Limit State and associated acceptance criteria Number of tracks on the bridge
1 2 ≥ 3
Traffic Safety Checks:      
–   Deck twist (EN 1990: A2.4.4.2.2) 1 1 or 2a 1 or 2 or 3 or moreb
–   Vertical deformation of the deck (EN 1990: A2.4.4.2.3) 1 l or 2a 1 or 2 or 3 or moreb
–   Horizontal deformation of the deck (EN 1990: A2.4.4.2.4) 1 l or 2a 1 or 2 or 3 or moreb
–   Combined response of structure and track to variable actions including limits to vertical and longitudinal displacement of the end of a deck (6.5.4) 1 l or 2a l or 2a
–   Vertical acceleration of the deck (6.4.6 and EN 1990: A2.4.4.2.1) 1 1 1
SLS Checks:      
–   Passenger comfort criteria (EN 1990: A2.4.4.3) 1 1 1
ULS Checks      
–   Uplift at bearings (EN 1990: A2.4.4.1(2)P) 1 l or 2a 1 or 2 or 3 or moreb
  1. Whichever is critical
  2. Where groups of loads are used the number of tracks to be loaded should be in accordance with Table 6.11. Where groups of loads are not used the number of tracks to be loaded should also be in accordance with Table 6.11.

NOTE Requirements for the number of tracks to be considered loaded when checking drainage and structural clearance requirements may be specified in the National Annex or for the individual project.

6.8.2 Groups of Loads - Characteristic values of the multicomponent action

  1. The simultaneity of the loading defined in 6.3 to 6.5 and 6.7 may be taken into account by considering the groups of loads defined in Table 6.11. Each of these groups of loads, which are mutually exclusive, should be considered as defining a single variable characteristic action for combination with non-traffic loads. Each Group of Loads should be applied as a single variable action. 118

    NOTE In some cases it is necessary to consider other appropriate combinations of unfavourable individual traffic actions. See A2.2.6(4) of EN 1990.

  2. The factors given in the Table 6.11 should be applied to the characteristic values of the different actions considered in each group.

    NOTE All the proposed values given for these factors may be varied in the National Annex. The values in Table 6.11 are recommended.

  3. P Where groups of loads are not taken into account rail traffic actions shall be combined in accordance with Table A2.3 of EN 1990.
119

Table 6.11 - Assessment of Groups of Loads for rail traffic (characteristic values of the multicomponent actions)

Table 6.11 - Assessment of Groups of Loads for rail traffic (characteristic values of the multicomponent actions)

6.8.3 Groups of Loads - Other representative values of the multicomponent actions

6.8.3.1 Frequent values of the multicomponent actions
  1. Where Groups of Loads are taken into account the same rule as in 6.8.2(1) above is applicable by applying the factors given in Table 6.11 for each Group of Loads, to the frequent values of the relevant actions considered in each Group of Loads.

    NOTE The frequent values of the multicomponent actions may be defined in the National Annex. The rules given in this clause are recommended.

    120
  2. P Where Groups of Loads are not used rail traffic actions shall be combined in accordance with Table A2.3 of EN 1990.
6.8.3.2 Quasi-permanent values of the multicomponent actions
  1. Quasi-permanent traffic actions should be taken as zero.

    NOTE The quasi-permanent values of the multicomponent actions may be defined in the National Annex. The value given in this clause is recommended.

6.8.4 Traffic loads in Transient Design Situations

  1. P Traffic loads for Transient Design Situations shall be defined.

    NOTE Some indications are given in annex H. The traffic loads for Transient Design Situations may be defined for the individual project.

6.9 Traffic loads for fatigue

  1. P A fatigue damage assessment shall be carried out for all structural elements, which are subjected to fluctuations of stress.
  2. For normal traffic based on characteristic values of Load Model 71, including the dynamic factor Φ, the fatigue assessment should be carried out on the basis of the traffic mixes, “standard traffic”, “traffic with 250 kN-axles” or “light traffic mix” depending on whether the structure carries mixed traffic, predominantly heavy freight traffic or lightweight passenger traffic in accordance with the requirements specified. Details of the service trains and traffic mixes considered and the dynamic enhancement to be applied are given in annex D.

    NOTE The requirements may be defined for the individual project.

  3. Where the traffic mix does not represent the real traffic (e.g. in special situations where a limited number of vehicle type(s) dominate the fatigue loading or for traffic requiring a value of α greater than unity in accordance with 6.3.2(3)) an alternative traffic mix should be specified.

    NOTE The alternative traffic mix may be defined for the individual project.

  4. Each of the mixes is based on an annual traffic tonnage of 25 × 106 tonnes passing over the bridge on each track.
  5. P For structures carrying multiple tracks, the fatigue loading shall be applied to a maximum of two tracks in the most unfavourable positions.
  6. The fatigue damage should be assessed over the design working life.

    NOTE The design working life may be specified in the National Annex. 100 years is recommended. See also EN 1990.

    121
  7. Alternatively, the fatigue assessment may be carried out on the basis of a special traffic mix.

    NOTE A special traffic mix may be specified in the National Annex or for the individual project.

  8. Additional requirements for the fatigue assessment of bridges where a dynamic analysis is required in accordance with 6.4.4 when dynamic effects are likely to be excessive are given in 6.4.6.6.
  9. Vertical rail traffic actions including dynamic effects and centrifugal forces should be taken into account in the fatigue assessment. Generally nosing and longitudinal traffic actions may be neglected in the fatigue assessment.

    NOTE In some special situations, for example bridges supporting tracks at terminal stations, the effect of longitudinal actions should be taken into account in the fatigue assessment.

122

Annex A
Models of special vehicles for road bridges

(informative)

A.1 Scope and field of application

  1. This annex defines standardised models of special vehicles that can be used for the design of road bridges.
  2. The special vehicles defined in this annex are intended to produce global as well as local effects such as are caused by vehicles which do not comply with the national regulations concerning limits of weights and, possibly, dimensions of normal vehicles.

    NOTE The consideration of special vehicles for bridge design is intended to be limited to particular cases.

  3. This annex also provides guidance in case of simultaneous application on a bridge carriageway of special vehicles and normal road traffic represented by Load Model 1 defined in 4.3.2.

A.2 Basic models of special vehicles

  1. Basic models of special vehicles are conventionally defined in Tables A.1 and A.2, and in Figure A. 1.

    NOTE 1 The basic models of special vehicles correspond to various levels of abnormal loads that can be authorised to travel on particular routes of the European highway network.

    NOTE 2 Vehicle widths of 3,00 m for the 150 and 200 kN axle-lines, and of 4,50 m for the 240 kN axle-lines are assumed.

    Table Al - Classes of special vehicles
    Total weight Composition Notation
    600 kN 4 axle-lines of 150 kN 600/150
    900 kN 6 axle-lines of 150 kN 900/150
    1200 kN 8 axle-lines of 150 kN
    or 6 axle-lines of 200 kN
    1200/150
    1200/200
    1500 kN 10 axle-lines of 150 kN
    or 7 axle-lines of 200 kN + 1 axle line of 100 kN
    1500/150
    1500/200
    1800 kN 12 axle-lines of 150 kN
    or 9 axle-lines of 200 kN
    1800/150
    1800/200
    2400 kN 12 axle-lines of 200 kN
    or 10 axle-lines of 240 kN
    or 6 axle-lines of 200 kN (spacing 12m) + 6 axle-lines of 200 kN
    2400/200
    2400/240
    2400/200/200 123
    3000 kN 15 axle-lines of 200 kN
    or 12 axle-lines of 240 kN + 1 axle-line of 120 kN
    or 8 axle-lines of 200 kN (spacing 12 m) + 7 axle-lines of 200 kN
    3000/200
    3000/240

    3000/200/200
    3600 kN 18 axle-lines of 200 kN
    or 15 axle-lines of 240 kN
    or 9 axle-lines of 200 kN (spacing 12 m) + 9 axle-lines of 200kN
    3600/200
    3600/240
    3600/200/200
    Table A2 - Description of special vehicles
      Axle-lines of 150 kN Axle-lines of 200 kN Axle-lines of 240 kN
    600 kN n = 4 × 150
    e = 1,50 m
       
    900 kN n = 6 × 150
    e = 1,50 m
       
    1200 kN n = 8 × 150
    e = 1,50 m
    n = 6 × 200
    e = 1,50 m
     
    1500 kN n = 10 × 150
    e = 1,50 m
    n = 1 × 100 + 7 × 200
    e = 1,50 m
     
    1800 kN n = 12 × 150
    e = 1,50 m
    n = 9 × 200
    e = 1,50 m
     
    2400 kN   n = 12 × 200
    e = 1,50 m
    Image n = 10 × 240 Image
    e = 1,50 m
        n = 6 × 200 + 6 × 200
    e = 5 × 1,5 + 12 + 5 × 1,5
     
    3000 kN   n = 15 × 200
    e = 1,50 m
    Image n = 1×120
    + 12 × 240 Image
    e = 1,50 m
        n = 8 × 200 + 7 × 200
    e = 7 × 1,5 + 12+6×1,5
     
    3600 kN   n = 18 × 200
    e = 1,50 m
    Image n = 15 × 240 Image
    e = 1,50 m
          n = 8 × 240 + 7 × 240
    e = 7 × 1,5+12+6×1,5

    NOTE

    n number of axles multiplied by the weight (kN) of each axle in each group

    e axle spacing (m) within and between each group.

    124

    Figure A.1 - Arrangement of axle-lines and definition of wheel contact areas

    Figure A.1 - Arrangement of axle-lines and definition of wheel contact areas

  2. One or more of the models of special vehicles may have to be taken into account.

    NOTE 1 The models and the load values and dimensions may be defined for the individual project.

    NOTE 2 The effects of the 600/150 standardised model are covered by the effects of Load Model 1 where applied with αQi and αqi factors all equal to 1.

    NOTE 3 Particular models, especially to cover the effects of exceptional loads with a gross weight exceeding 3600 kN, may have to be defined for the individual project.

  3. The characteristic loads associated with the special vehicles should be taken as nominal values and should be considered as associated solely with transient design situations.

A.3 Application of special vehicle load models on the carriageway

  1. Each standardised model should be applied :
  2. The notional lanes should be located as unfavourably as possible in the carriageway. For this case, the carriageway width may be defined as excluding hard shoulders, hard strips and marker strips. 125

    Figure A.2 - Application of the special vehicles on notional lanes

    Figure A.2 - Application of the special vehicles on notional lanes

  3. Depending on the models under consideration, these models may be assumed to move at low speed (not more than 5 km/h) or at normal speed (70 km/h).
  4. Where the models are assumed to move at low speed, only vertical loads without dynamic amplification should be taken into account.
  5. Where the models are assumed to move at normal speed, a dynamic amplification should be taken into account. The following formula may be used :

    Image

    where:

    L     influence length (m)

  6. Where the models are assumed to move at low speed, each notional lane and the remaining area of the bridge deck should be loaded by Load Model 1 with its frequent values defined in 4.5 and in A2 to EN 1990. On the lane(s) occupied by the standardised vehicle, this system should not be applied at less than 25 m from the outer axles of the vehicle under consideration (see Figure A.3). 126

    Figure A.3 - Simultaneity of Load Model 1 and special vehicles

    Figure A.3 - Simultaneity of Load Model 1 and special vehicles

  7. Where special vehicles are assumed to move at normal speed, a pair of special vehicles should be used in the lane(s) occupied by these vehicles. On the other lanes and the remaining area the bridge deck should be loaded by Load Model 1 with its frequent values defined in 4.5 and in EN 1990, A2.
127

Annex B
Fatigue life assessment for road bridges Assessment method based on recorded traffic

(informative)

  1. A stress history should be obtained by analysis using recorded representative real traffic data, multiplied by a dynamic amplification factor φfat.
  2. This dynamic amplification factor should take into account the dynamic behaviour of the bridge and depends on the expected roughness of the road surface and on any dynamic amplification already included in the records.

    NOTE In accordance with ISO 86087, the road surface can be classified in terms of the power spectral density (PSD) of the vertical road profile displacement Gd, i.e. of the roughness. Gd is a function of the spatial frequency n, Gd(n), or of the angular spatial frequency of the path Ω, Gd(Ω), with Ω=2πn. The actual power spectral density of the road profile should be smoothed and then fitted, in the bi-logarithmic presentation plot, by a straight line in an appropriate spatial frequency range. The fitted PSD can be expressed in a general form as

    Image

    where :

    n0 is the reference spatial frequency (0,1 cycle/m),
    Ω0 is the reference angular spatial frequency (1 rd/m),
    w is the exponent of the fitted PSD.

    Often, instead of displacement PSD, Gd, it is convenient to consider velocity PSD, Gv, in terms of change of the vertical ordinate of the road surface per unit distance travelled. Since the relationships between Gv and Gd are :

    Gv(n) = Gd(n)(2πn)2     and     Gv(Ω) = Gd(Ω)(Ω)2

    When w=2 the two expressions of velocity PSD are constant.

    Considering constant velocity PSD, 8 different classes of roads (A, B, …, H) with increasing roughness are considered in ISO 8608. The class limits are graphed versus the displacement PSD in Figure B.1 . For road bridge pavement classification only the first 5 classes (A, B, …, E) are relevant.

    Quality surface may be assumed very good for road surfaces in class A, good for surfaces in class B, medium for surfaces in class C, poor for surfaces in class D and very poor for surfaces in class E.

    7ISO 8608:1995 – Mechanical vibration – Road surface profiles – Reporting of measured data

    128

    Figure B.1 - Road surface classification (ISO 8608)

    Figure B.1 - Road surface classification (ISO 8608)

    The limit values of Gd and Gv for the first 5 road surface classes in terms of n and Ω are given in Tables B.1 and B.2, respectively.

    129
    Table B.1 - Degree of roughness expressed in terms of spatial frequency units, n
      Degree of roughness
    Road class Pavement quality Gd (n0)a[10−6m] Gv(n) [10−6m]
    Lower limit Geometric mean Upper limit Geometric mean
    A Very good --- 16 32 6,3
    B Good 32 64 128 25,3
    C Medium 128 256 512 101,1
    D Poor 512 1024 2048 404,3
    E Very poor 2048 4096 8192 1617,0
    a n0=0.1 cycle/m
    Table B.2 - Degree of roughness expressed in terms of angular spatial frequency units, Ω
      Degree of roughness
    Road class Pavement quality Gd0)a[10−6m] Gv(Ω) [10−6m]
    Lower limit Geometric mean Upper limit Geometric mean
    A Very good --- 1 2 1
    B Good 2 4 8 4
    C Medium 8 16 32 16
    D Poor 32 64 128 64
    E Very poor 128 256 512 256
    a Ω0=1 rad/m
  3. Unless otherwise specified, the recorded axle loads should be multiplied by :

    φfat = 1,2 for surface of good roughness

    φfat = 1,4 for surface of medium roughness.

  4. In addition, when considering a cross-section within a distance of 6,00 m from an expansion joint, the load should be multiplied by the additional dynamic amplification factor Δφfat derived from Figure 4.7.
  5. The classification of roadway roughness may be taken in accordance with ISO 8608.
  6. For a rough and quick estimation of the roughness quality, the following guidance is given :
  7. The wheel contact areas and the transverse distances between wheels should be taken as described in Table 4.8, where relevant. 130
  8. If the data are recorded on one lane only, assumptions should be made concerning the traffic on other lanes. These assumptions may be based on records made at other locations for a similar type of traffic.
  9. The stress history should take into account the simultaneous presence of vehicles recorded on the bridge in any lane. A procedure should be developed to allow for this when records of individual vehicle loadings are used as a basis.
  10. The numbers of cycles should be counted using the rainflow method or the reservoir method.
  11. If the duration of recordings is less than a full week, the records and the assessment of the fatigue damage rates may be adjusted taking into account observed variations of traffic flows and mixes during a typical week. An adjustment factor should also be applied to take into account any future changes on the traffic
  12. The cumulative fatigue damage calculated by use of records should be multiplied by the ratio between the design working life and the duration considered on the histogram. In the absence of detailed information, a factor 2 for the number of lorries and a factor 1,4 for the load levels are recommended.
131

Annex C
Dynamic factors 1 + φ for Real Trains

(normative)

  1. P To take account of dynamic effects resulting from the movement of actual service trains at speed, the forces and moments calculated from the specified static loads shall be multiplied by a factor appropriate to the Maximum Permitted Vehicle Speed.
  2. The dynamic factors 1 + φ are also used for fatigue damage calculations.
  3. P The static load due to a Real Train at v [m/s] shall be multiplied by:

    either, 1 + φ = 1 + φ′ + φ″ for track with standard maintenance     (C.1)

    or, 1 + φ = 1 + φ′ + 0,5 φ″ for carefully maintained track     (C.2)

    NOTE The National Annex may specify whether expression (C.1) or (C.2) may be used. Where the expression to be used is not specified, expression (C.1) is recommended.

    with:

    Image

    and

    φ′ = 1,325 for K ≥ 0,76     (C,4)

    Image

    and

    Image

    φ″ ≥ 0

    Image

    where

    v is the Maximum Permitted Vehicle Speed [m/s]
    no is the first natural bending frequency of the bridge loaded by permanent actions [Hz]
    LΦ is the determinant length [m] in accordance with 6.4.5.3.
    α is a coefficient for speed

    The limit of validity for φ′ defined by Equations (C.3) and (C.4) is the lower limit of natural frequency in Figure 6.10 and 200 km/h. For all other cases φ′ should be determined by a dynamic analysis in accordance with 6.4.6.

    NOTE The method used should be agreed with the relevant authority specified in the National Annex.

    132

    The limit of validity for φ″ defined by Equation (C.6) is the upper limit of natural frequency in Figure 6.10. For all other cases φ″ may be determined by a dynamic analysis taking into account mass interaction between the unsprung axle masses of the train and the bridge in accordance with 6.4.6.

  4. P The values of φ′ + φ″ shall be determined using upper and lower limiting values of no, unless it is being made for an individual bridge of known first natural frequency.

    The upper limit of no is given by:

    n0 = 94,76LΦ−0.748     (C.8)

    and the lower limit is given by:

    Image

    n0 = 23,58LΦ−0,592     for 20m < LΦ ≤ 100 m     (C,10)

133

Annex D
Basis for the fatigue assessment of railway structures

(normative)

D.1 Assumptions for fatigue actions

  1. The dynamic factors Φ2 and Φ3 which are applied to the static Load Model 71 and SW/0 and SW/2, when clause 6.4.5 applies, represent the extreme loading case to be taken into account for detailing bridge members. These factors would be unduly onerous if they were applied to the Real Trains used for making an assessment of fatigue damage.
  2. To take account of the average effect over the assumed 100 years life of the structure, the dynamic enhancement for each Real Train may be reduced to:

    l + ½(φ′ + ½φ″)     (D.1)

    where φ′ and φ″ are defined below in equations (D.2) and (D.5).

  3. Equations (D.2) and (D.5) are simplified forms of equations (C.3) and (C.6) which are sufficiently accurate for the purpose of calculating fatigue damage and are valid for Maximum Permitted Vehicle Speeds up to 200km/h:

    Image

    with:

    Image

    Image

    and

    Image

    where:

    v is the Maximum Permitted Vehicle Speed [m/s]
    L is the determinant length LΦ [m] in accordance with 6.4.5.3

    NOTE Where dynamic effects including resonance may be excessive and a dynamic analysis is required in accordance with 6.4.4 additional requirements for the fatigue assessment of bridges are given in 6.4.6.6.

134

D.2 General design method

  1. P The fatigue assessment, in general a stress range verification, shall be carried out according to EN 1992, EN 1993 and EN 1994.
  2. As an example for steel bridges the safety verification shall be carried out by ensuring that the following condition is satisfied:

    Image

    where:

    γFf is the partial safety factor for fatigue loading

    NOTE The value for γFf may be given in the National Annex. The recommended value is γFf = 1,00.

    λ is the damage equivalence factor for fatigue which takes account of the service traffic on the bridge and the span of the member. Values of λ are given in the design codes Image (EN 1992 – EN 1999). Image
    Φ2 is the dynamic factor (see 6.4.5)
    Δσ71 is the stress range due to the Load Model 71 (and where required SW/0) but excluding α) being placed in the most unfavourable position for the element under consideration
    ΔσC is the reference value of the fatigue strength (see EN 1993)
    γMf is the partial safety factor for fatigue strength in the design codes Image (EN 1992 – EN 1999) Image

D.3 Train types for fatigue

The fatigue assessment should be carried out on the basis of the traffic mixes, “standard traffic”, “traffic with 250 kN-axles” or “light traffic mix”, depending on whether the structure carries standard traffic mix, predominantly heavy freight traffic or light traffic.

Details of the service trains and traffic mixes are given below.

135
  1. Standard and light traffic mixes

    Type 1     Locomotive-hauled passenger train

    Σ Q = 6630kN V = 200km/h L = 262,10m q = 25,3kN/m’

    Image

    Type 2     Locomotive-hauled passenger train

    Σ Q = 5300kN V = 160km/h L = 281,10m q = 18,9kN/m’

    Image

    Type 3     High speed passenger train

    Σ Q = 9400kN V = 250km/h L = 385,52m q = 24,4kN/m’

    Image

    136

    Type 4     High speed passenger train

    Σ Q = 5100kN V = 250km/h L = 237,60m q = 21,5kN/m’

    Image

    Type 5     Locomotive-hauled freight train

    Σ Q = 21600kN V = 80km/h L = 270,30m q = 80,0kN/m’

    Image

    Type 6     Locomotive-hauled freight train

    Σ Q = 14310kN V = 100km/h L = 333,10m q = 43,0kN/m’

    Image

    137

    Type 7     Locomotive-hauled freight train

    Σ Q = 10350kN V = 120km/h L = 196,50m q = 52,7kN/m’

    Image

    Type 8     Locomotive-hauled freight train

    Σ Q = 10350kN V = 100km/h L = 212,50m q = 48,7kN/m’

    Image

    Type 9     Surburban multiple unit train

    Σ Q = 2960kN V = 120km/h L = 134,80m q = 22,0kN/m’

    Image

    138

    Type 10     Underground

    Σ Q = 3600kN V = 120km/h L = 129,60m q = 27,8kN/m’

    Image

  2. Heavy traffic with 250 kN - axles

    Type 11     Locomotive-hauled freight train

    Σ Q = 11350kN V = 120km/h L = 198,50m q = 57,2kN/m’

    Image

    Type 12     Locomotive-hauled freight train

    Σ Q = 11350kN V = 100km/h L = 212,50m q = 53,4kN/m’

    Image

    139
  3. Traffic mix:
    Table D.1 - Standard traffic mix with axles ≤ 22,5 t (225 kN)
    Train type Number of trains/day Mass of train [t] Traffic volume [106t/year]
    1 12 663 2,90
    2 12 530 2,32
    3 5 940 1,72
    4 5 510 0,93
    5 7 2160 5,52
    6 12 1431 6,27
    7 8 1035 3,02
    8 6 1035 2,27
      67   24,95
    Table D.2 - Heavy traffic mix with 25t (250 kN) axles
    Train type Number of trains/day Mass of train [t] Traffic volume [106t/year]
    5 6 2160 4,73
    6 13 1431 6,79
    11 16 1135 6,63
    12 16 1135 6,63
      51   24,78
    Table D.3 - Light traffic mix with axles ≤ 22,5 t (225 kN)
    Train type Number of trains/day Mass of train [t] Traffic volume [106t/year]
    1 10 663 2,4
    2 5 530 1,0
    5 2 2160 1,4
    9 190 296 20,5
      207   25,3
140

Annex E
Limits of validity of Load Model HSLM and the selection of the critical Universal Train from HSLM-A

(informative)

E.1 Limits of validity of Load Model HSLM

  1. Load Model HSLM is valid for passenger trains conforming to the following criteria:
    Table E.1 - Limiting parameters for high speed passenger trains conforming to Load Model HSLM
    Type of train P [kN] D [m] DIC [m] ec [m]
    Articulated 170 18 ≤ D ≤ 27 - -
    Conventional Lesser of 170 or value corresponding to equation E.2 below. 18 ≤ D ≤ 27 - -
    Regular 170 10 ≤ D ≤ 14 8 ≤ DIC ≤ 11 7 ≤ ec ≤ 10

    where:

    141

    Image

    where:

    PHSLMA, dHSLMA and DHSLMA are the parameters of the Universal Trains in accordance with Figure 6.12 and Table 6.3 corresponding to the coach length DHSLMA for:

    and D, DIC, P, dBA, dBS and ec are defined as appropriate for articulated, conventional and regular trains in Figures E.1 to E.3:

    Figure E1 - Articulated train

    Figure E1 - Articulated train

    Figure E2 - Conventional train

    Figure E2 - Conventional train

    Figure E3 - Regular train

    Figure E3 - Regular train

  2. The point forces, dimensions and lengths of the Universal Trains defined in 6.4.6.1.1 do not form part of the real vehicle specification unless referenced in E.1(1).

E.2 Selection of a Universal Train from HSLM-A

  1. For simply supported spans that exhibit only line beam dynamic behaviour and with a span of 7 m or greater a single Universal Train derived from the load model HSLM-A may be used for the dynamic analysis. 142
  2. The critical Universal Train is defined in E.2(5) as a function of:

    where the critical wavelength of excitation λc is a function of:

  3. The wavelength of excitation at the Maximum Design Speed λv [m] is given by:

    λv = vDS/no     (E.3)

    where:

    no First natural frequency of the simply supported span [Hz]
    vDS Maximum Design Speed in accordance with 6.4.6.2(1) [m/s]
  4. The critical wavelength of excitation λc should be determined from Figures E.4 to E.17 as the value of λ corresponding to the maximum value of aggressivity A(L/λ)G(λ) for the span of length L [m] in the range of excitation wavelength from 4,5 m to λv.

    Where the span of the deck does not correspond to the reference length L in figures E.4 to E.17, the two figures corresponding to the values of L taken as either just greater than the span or just less than the span of the deck should be taken into account. The critical wavelength of excitation λc should be determined from the figure corresponding to the maximum aggressivity. Interpolation between the diagrams is not permitted.

    NOTE It can be seen from Figures E.4 to E.17 that in many cases λc = λv but in some cases λc corresponds to a peak value of aggressivity at a value of λ less than λv (For example in Figure E.4 for λv = 17m, λc = 13m)

    Figure E.4 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 7,5 m and damping ratio Ϛ = 0.01

    Figure E.4 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 7,5 m and damping ratio ζ = 0.01

    143

    Figure E.5 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 10,0 m and damping ratio ζ = 0.01

    Figure E.5 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 10,0 m and damping ratio ζ = 0.01

    Figure E.6 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 12,5 m and damping ratio ζ = 0.01

    Figure E.6 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 12,5 m and damping ratio ζ = 0.01

    Figure E.7 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 15,0 m and damping ratio ζ = 0.01

    Figure E.7 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 15,0 m and damping ratio ζ = 0.01

    144

    Figure E.8 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 17,5 m and damping ratio ζ = 0.01

    Figure E.8 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 17,5 m and damping ratio ζ = 0.01

    Figure E.9 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 20,0 m and damping ratio ζ = 0.01

    Figure E.9 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 20,0 m and damping ratio ζ = 0.01

    Figure E.10 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 22,5 m and damping ratio ζ = 0.01

    Figure E.10 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 22,5 m and damping ratio ζ = 0.01

    145

    Figure E.11 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 25,0 m and damping ratio ζ = 0.01

    Figure E.11 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 25,0 m and damping ratio ζ = 0.01

    Figure E.12 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 27,5 m and damping ratio ζ = 0.01

    Figure E.12 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 27,5 m and damping ratio ζ = 0.01

    Figure E.13 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 30,0 m and damping ratio ζ = 0.01

    Figure E.13 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 30,0 m and damping ratio ζ = 0.01

    146

    Figure E.14 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 32,5 m and damping ratio ζ = 0.01

    Figure E.14 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 32,5 m and damping ratio ζ = 0.01

    Figure E.15 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 35,0 m and damping ratio ζ= 0.01

    Figure E.15 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 35,0 m and damping ratio ζ= 0.01

    Figure E.16 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 37,5 m and damping ratio ζ = 0.01

    Figure E.16 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 37,5 m and damping ratio ζ = 0.01

    147

    Figure E.17 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 40,0 m and damping ratio ζ = 0.01

    Figure E.17 - Aggressivity A(L/λG(λ) as a function of excitation wavelength λ for a simply supported span of L = 40,0 m and damping ratio ζ = 0.01

  5. The critical Universal Train in HSLM-A is defined in Figure E.18:

    Figure E.18 - Parameters defining critical Universal Train in HSLM-A as a function of critical wavelength of excitation λc [m]

    Figure E.18 - Parameters defining critical Universal Train in HSLM-A as a function of critical wavelength of excitation λc [m]

    NOTE For values of Image λc Image < 7 m it is recommended that the dynamic analysis is carried out with Universal Trains Al to A10 inclusive in accordance with Table 6.3.

    Where:

    D Length of intermediate and end coaches defined in Figure 6.12 [m]
    d Spacing of bogie axles for intermediate and end coaches defined in Figure 6.12 [m]
    N Number of intermediate coaches defined in Figure 6.12
    Pk Point force at each axle position in intermediate and end coaches and in each power car as defined in Figure 6.12 [kN]
    λc Critical wavelength of excitation given in E.2(4) [m]
  6. Alternatively the aggressivity A(L/λ)G(λ) [kN/m] is defined by equations E.4 and E.5:
148

Image

Image

where i is taken from 0 to (M-1) to cover all sub-trains including the whole train and:

L Span [m]
M Number of point forces in train
Pk Load on axle k [kN]
Xi Length of sub-train consisting of i axles
xk Distance of point force Pk from first point force P0 in train [m]
λ Wavelength of excitation [m]
ζ Damping ratio
149

Annex F
Criteria to be satisfied if a dynamic analysis is not required

(informative)

NOTE Annex F is not valid for Load Model HSLM (Annex F is valid for the trains given in F(4)).

  1. For simply supported structures satisfying the maximum value of (v/n0)lim given in Tables F.1 and F.2:

    do not exceed the values due to Φ2 × Load Model 71 and no further dynamic analysis is necessary and

    Table F.1 - Maximum value of (v/no)lim for a simply supported beam or slab and a maximum permitted acceleration of αmax< 3.50m/s2.
    Mass m 103 kg/m ≥5,0 <7,0 ≥7,0 <9,0 ≥9,0 <10,0 ≥10,0 <13,0 ≥13,0 <15,0 ≥15,0 <18,0 ≥18,0 <20,0 ≥20,0 <25,0 ≥25,0 <30,0 ≥30,0 <40,0 ≥40,0 <50,0 ≥50,0
    -
    Span Lϵ ma ζ % v/n0 m v/n0 m v/n0 m v/n0 m v/n0 m v/n0 m v/n0 m v/n0 m v/n0 m v/n0 m v/n0 m v/n0 m
    [5,00,7,50) 2 1,71 1,78 1,88 1,88 1,93 1,93 2,13 2,13 3,08 3,08 3,54 3,59
      4 1,71 1,83 1,93 1,93 2,13 2,24 3,03 3,08 3,38 3,54 4,31 4,31
    [7,50,10,0) 2 1,94 2,08 2,64 2,64 2,77 2,77 3,06 5,00 5,14 5,20 5,35 5,42
      4 2,15 2,64 2,77 2,98 4,93 5,00 5,14 5,21 5,35 5,62 6,39 6,53
    [10,0,12,5) 1 2,40 2,50 2,50 2,50 2,71 6,15 6,25 6,36 6,36 6,45 6,45 6,57
      2 2,50 2,71 2,71 5,83 6,15 6,25 6,36 6,36 6,45 6,45 7,19 7,29
    [12,5,15,0) 1 2,50 2,50 3,58 3,58 5,24 5,24 5,36 5,36 7,86 9,14 9,14 9,14
      2 3,45 5,12 5,24 5,24 5,36 5,36 7,86 8,22 9,53 9,76 10,36 10,48
    [15,0,17,5) 1 3,00 5,33 5,33 5,33 6,33 6,33 6,50 6,50 6,50 7,80 7,80 7,80
      2 5,33 5,33 6,33 6,33 6,50 6,50 10,17 10,33 10,33 10,50 10,67 12,40
    [17,5,20,0) 1 3,50 6,33 6,33 6,33 6,50 6,50 7,17 7,17 10,67 12,80 12,80 12,80
    [20,0,25,0) 1 5,21 5,21 5,42 7,08 7,50 7,50 13,54 13,54 13,96 14,17 14,38 14,38
    [25,0,30,0) 1 6,25 6,46 6,46 10,21 10,21 10,21 10,63 10,63 12,75 12,75 12,75 12,75
    [30,0,40,0) 1       10,56 18,33 18,33 18,61 18,61 18,89 19,17 19,17 19,17
    ≥40,0 1       14,73 15,00 15,56 15,56 15,83 18,33 18,33 18,33 18,33

    a L ϵ [a,b] means aL < b

    NOTE 1 Table F. 1 includes a safety factor of 1.2 on (v/n0)lim for acceleration, deflection and strength criteria and a safety factor of 1,0 on the (v/n0)lim for fatigue.

    NOTE 2 Table F. 1 includes an allowance of (1 + φ″/2) for track irregularities.

    150
    Table F.2 - Maximum value of (v/no)lim for a simply supported beam or slab and a maximum permitted acceleration of amax < 5.0 m/s2
    Mass m 103 kg/m ≥5,0 <7,0 ≥7,0 <9,0 ≥9,0 <10,0 ≥10,0 <13,0 ≥13,0 <15,0 ≥15,0 <18,0 ≥18,0 <20,0 ≥20,0 <25,0 ≥25,0 <30,0 ≥30,0 <40,0 ≥40,0 <50,0 ≥50,0
    -
    Span Lϵ ma ζ % v/n0 m v/n0 m v/n0 m v/n0 m v/n0 m v/n0 m v/n0 m v/n0 m v/n0 m v/n0 m v/n0 m v/n0 m
    [5,00,7,50) 2 1,78 1,88 1,93 1,93 2,13 2,13 3,08 3,08 3,44 3,54 3,59 4,13
      4 1,88 1,93 2,13 2,13 3,08 3,13 3,44 3,54 3,59 4,31 4,31 4,31
    [7,50,10,0) 2 2,08 2,64 2,78 2,78 3,06 5,07 5,21 5,21 5,28 5,35 6,33 6,33
      4 2,64 2,98 4,86 4,93 5,14 5,21 5,35 5,42 6,32 6,46 6,67 6,67
    [10,0,12,5) 1 2,50 2,50 2,71 6,15 6,25 6,36 6,36 6,46 6,46 6,46 7,19 7,19
      2 2,71 5,83 6,15 6,15 6,36 6,46 6,46 6,46 7,19 7,19 7,75 7,75
    [12,5,15,0) 1 2,50 3,58 5,24 5,24 5,36 5,36 7,86 8,33 9,14 9,14 9,14 9,14
      2 5,12 5,24 5,36 5,36 7,86 8,22 9,53 9,64 10,36 10,36 10,48 10,48
    [15,0,17,5) 1 5,33 5,33 6,33 6,33 6,50 6,50 6,50 7,80 7,80 7,80 7,80 7,80
      2 5,33 6,33 6,50 6,50 10,33 10,33 10,50 10,50 10,67 10,67 12,40 12,40
    [17,5,20,0) 1 6,33 6,33 6,50 6,50 7,17 10,67 10,67 12,80 12,80 12,80 12,80 12,80
    [20,0,25,0) 1 5,21 7,08 7,50 7,50 13,54 13,75 13,96 14,17 14,38 14,38 14,38 14,38
    [25,0,30,0) 1 6,46 10,20 10,42 10,42 10,63 10,63 12,75 12,75 12,75 12,75 12,75 12,75
    [30,0,40,0) 1       18,33 18,61 18,89 18,89 19,17 19,17 19,17 19,17 19.17
    ≤40,0 1       15,00 15,56 15,83 18,33 18,33 18,33 18,33 18,33 18,33

    a L ϵ [a,b) means aL < b

    NOTE 1 Table F.2 includes a safety factor of 1.2 on (v/n0)lim for acceleration, deflection and strength criteria and a safety factor of 1,0 on the (v/n0)lim for fatigue.

    NOTE 2 Table F.2 include an allowance of (1 + φ″/2) for track irregularities.

    where:

    L is the span length of bridge [m],
    m is the mass of bridge [103 kg/m],
    ζ is the percentage of critical damping in [%],
    v is the Maximum Nominal Speed and is generally the Maximum Line Speed at the site. A reduced speed may be used for checking individual Real Trains for their associated Maximum Permitted Vehicle Speed [m/s],
    no is the first natural frequency of the span [Hz].
    Φ2 and φ are defined in 6.4.5.2 and annex C.
  2. Tables F.1 and F.2 are valid for:
  3. Where the above criteria are not satisfied a dynamic analysis should be carried out in accordance with 6.4.6.
  4. The following Real Trains were used in the development of the criteria in 6.4 and annex F (except Load Model HSLM which is based upon the train types permitted by the relevant interoperability criteria).

Type A

Σ Q = 6936kN V = 350km/h L = 350,52m q = 19,8kN/m’

Image

Type B

Σ Q = 8784KN V = 350km/h L = 393,34m q = 22,3KN/m’

Image

152

Type C

Σ Q = 8160kN V = 350km/h L = 386,67m q = 21,1 kN/m’

Image

Type D

Σ Q = 6296kN V = 350km/h L = 295,70m q = 21,3kN/m’

Image

Type E

Σ Q = 6800kN V = 350km/h L = 356,05m q = 19,1 kN/m’

Image

153

Type F

Σ Q = 7480kN V = 350km/h L = 258,70m q = 28,9kN/m’

Image

154

Annex G
Method for determining the combined response of a structure and track to variable actions

(informative)

G.1 Introduction

  1. A method for determining the combined response of a structure and track to variable actions is given below for:
  2. In each case requirements are given for:
  3. In all cases a separate check should be made for compliance with the maximum vertical displacement of the upper surface of a deck given in 6.5.4.5.2(3).

G.2 Limits of validity of calculation method

  1. Track construction:
  2. Bridge configuration:
  3. Longitudinal plastic shear resistance k of the track:
    unloaded track: k = 20 to 40 kN per m of track,
    loaded track: k = 60 kN per m of track. 155
  4. Vertical traffic loading:

    NOTE The method is valid for values of a where the load effects from α × LM71 are less than or equal to the load effects from SW/2.

  5. Actions due to braking:
  6. Actions due to traction:
  7. Actions due to temperature:

G.3 Structures consisting of a single bridge deck

  1. Initially the following values should be determined neglecting the combined response of the structure and track to variable actions:
  2. For the couples of values (unloaded/loaded track) of the longitudinal plastic shear resistance of the track k = 20/60 kN per m of track and k=40/60 kN per m of track and the linear temperature coefficient αT = 10E−6 1/Kelvin or αT = 12E-6 l/Kelvin the maximum permissible expansion length LTP [m] is given in Figure G.1 to G.4 as appropriate. 156

    Where the point (LT, δ) describing the expansion length of the deck and longitudinal displacement of the deck end due to vertical traffic actions lies below the corresponding or interpolated curve corresponding to the longitudinal stiffness of the substructure K, the maximum permissible additional rail stresses given in 6.5.4.5.1(1) and the maximum permissible deformation of the structure given in 6.5.4.5.2(1) due to traction and braking and 6.5.4.5.2(2) due to vertical traffic actions are satisfied.

    Alternatively, if this condition is not met an analysis may be carried out in accordance with the requirements of 6.5.4.2 to 6.5.4.5 or rail expansion devices should be provided.

    Figure G.1 - Permissible domain for rail stresses in simply supported deck bridges for αT = 10E-6 [1/Kelvin], ΔT = 35 [Kelvin], k20/k60 = 20/60 [kN/m]

    Figure G.1 - Permissible domain for rail stresses in simply supported deck bridges for αT = 10E-6 [1/Kelvin], ΔT = 35 [Kelvin], k20/k60 = 20/60 [kN/m]

    157

    Figure G.2 - Permissible domain for rail stresses in simply supported deck bridges for aT = 10E-6 [1/Kelvin], ΔT = 35 [Kelvin], kjkm = 40/60 [kN/m]

    Figure G.2 - Permissible domain for rail stresses in simply supported deck bridges for αT = 10E-6 [1/Kelvin], ΔT = 35 [Kelvin], k40/k60 = 40/60 [kN/m]

    158

    Figure G.3 - Permissible domain for rail stresses in simply supported deck bridges for αT = 12E-6 [1/Kelvin], ΔT = 35 [Kelvin], k20/k60 = 20/60 [kN/m]

    Figure G.3 - Permissible domain for rail stresses in simply supported deck bridges for αT = 12E-6 [1/Kelvin], ΔT = 35 [Kelvin], k20/k60 = 20/60 [kN/m]

    159

    Figure G.4 - Permissible domain for rail stresses in simply supported deck bridges for αT = 12E-6 [1/Kelvin], ΔT = 35 [Kelvin], k40/k60 = 40/60 [kN/m]

    Figure G.4 - Permissible domain for rail stresses in simply supported deck bridges for αT = 12E-6 [1/Kelvin], ΔT = 35 [Kelvin], k40/k60 = 40/60 [kN/m]

  3. Actions in the longitudinal bridge direction on the (fixed) bearings due to traction and braking, to temperature variation and due to the deformation of the deck under vertical traffic loads should be determined with the formulae given in Table G. 1. The formulae are valid for one track. For two or more tracks with a support stiffness of KU the actions on the fixed bearings may be determined by assuming a support stiffness of K = KU /2 and multiplying the results of the formulae for one track by 2.
160
Table G.1 - Actions on the fixed bearings in longitudinal bridge direction a
Load case Limits of validity Continuous welded rails With one rail expansion device
Brakinge L ≥ 50 m d 82.10−3 × L0.9 × K0.4 b 2,26 × L1.1 × K0.1 b
  L ≥ 30 md 126.10−3 × L0.9 × K0.4 3,51 × L1.1 × K0.1
      800 + 0,5L + 0,01 K/Lc for L ≥ 60 m
Temperature 20 ≤ k [kN/m] ≤ 40 (0,34 + 0,013k)L0.95 × K0.25 c 20 L for L ≤ 40m
      Interpolated values for 40<L<60 m
End rotation Deck bridge 0,1 1L0,22 × K0,5 × (1,1-β) × θH0,86 Same as continuous welded rail
Through and half through bridge 0,1 1L0,22 × K0,5 × (1,1-β) × θH Same as continuous welded rail
  1. Where rail expansion devices are provided at both ends of the deck all the traction and braking forces are resisted by the fixed bearings. Actions on the fixed bearings due to temperature variation and end rotation due to vertical deflection depend upon the structural configuration and associated expansion lengths.
  2. The braking force applied to the fixed bearings is limited to a maximum of 6000 kN per track.
  3. The force applied to the fixed bearings due to temperature is subject to a limit of 1340 kN where rail expansion devices are provided to all rails at one end of the deck.
  4. For values of L in the range 30 < L < 50 m linear interpolation may be used to estimate braking effects.
  5. The formulae for braking take into account the effects of traction.

where:

K is the support stiffness as defined above [kN/m],
L depends upon the structural configuration and type of variable action as follows [m]:
  • – For a simply supported deck with fixed bearing at one end:

    L = LT,

  • – For a multiple span continuous deck with a fixed bearing at one end:

    for “Braking”:

    L = LDeck (total length of the deck),

    for “Temperature”:

    L = LT,

    for “End rotation due to vertical traffic loads”:

    L = length of the span next to the fixed bearing,

  • – For a multiple span continuous deck with a fixed bearing at an intermediate position:

    for “Braking”:

    L = LDeck (total length of the deck),

    for “Temperature”:

    the actions due to temperature variation can be determined as the algebraic sum of the support reactions of the two static arrangements obtained by dividing the deck at the fixed bearing section, each deck having the fixed bearing at the intermediate support,

    161

    for “End rotation due to vertical traffic loads”:

    L = length of the longest span at the fixed support,

β is the ratio of the distance between the neutral axis and the surface of the deck relative to the height H [ratio].

G.4 Structures consisting of a succession of decks

  1. In addition to the limits of validity given in G.3 the following limits of validity are applicable:
  2. The longitudinal support reactions FLj due to temperature variations, traction and braking and deformation of the deck may be determined as follows:

    Actions FL0on the fixed bearing (j = 0) on the abutment:

FL0(qv) = FL0(ΘH)     (G.4)

determined in accordance with G.3 for single deck bridges where ΘH is in [mm].

Finally, the actions on the fixed bearings on the piers should be determined in accordance with Table G.2.

Table G.2 - Formulae for the calculation of bearing reactions for a succession of decks
Support j = 0 … n Temperature variation
FLjT)
Traction/Braking
FLj (qL)
Deformation of the deck
FLj(ΘH)
Abutment with first fixed bearing
j = 0
FL0T) FL0 (qL) = KqLL0 FL0(ΘH)
First pier
j = 1
FL1T) = 0,2 FL0T) FL2 (qL) = qLL1 FL1 (ΘH) = 0
Intermediate piers
j = m
FLmT) = 0 FLm (qL) = qL Lm FLm(ΘH) = 0
(n-1)th pier
j = (n-1)
FL(n-1)T) = 0,lFL0T) FL(n-1) (qL) = qL L(n-1) FL(n-1)(ΘH) = 0
(n)th pier
j = n
FLnT) = 0,5 FL0T) FLn (qL) = qL Ln FLn(ΘH) = 0,5FL0 (ΘH)

NOTE 1 The formulae for braking take into account the effects of traction.

NOTE 2 The braking force applied to the fixed bearings is limited to a maximum of 6000 kN per track.

NOTE 3 The force applied to the fixed bearings due to temperature is subject to a limit of 1340 kN where one rail expansion device is provided.

163

Annex H
Load models for rail traffic loads in Transient Design Situations

(informative)

  1. When carrying out design checks for Transient Design Situations due to track or bridge maintenance, the characteristic values of Load Model 71, SW/0, SW/2, “unloaded train” and HSLM and associated rail traffic actions should be taken equal to the characteristic values of the corresponding loading given in Section 6 for the Persistent Design Situation.

****************************************

164 165