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 199914:2007/A1
August 2011
ICS 91.010.30; 91.080.10
English Version
Eurocode 9: Design of aluminium structures  Part 14: Coldformed structural sheeting
Eurocode 9  Calcul des structures en aluminium  Partie 14: Tôles de structure formées à froid 
Eurocode 9: Bemessung und Konstruktion von Aluminiumtragwerken  Teil 14: Kaltgeformte Profiltafeln 
This amendment A1 modifies the European Standard EN 199914:2007; it was approved by CEN on 8 April 2011.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for inclusion of this amendment into the relevant national standard without any alteration. Uptodate lists and bibliographical references concerning such national standards may be obtained on application to the CENCENELEC Management Centre or to any CEN member.
This amendment 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 CENCENELEC Management Centre has the same status as the official versions.
CEN members are the national standards bodies of 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 United Kingdom.
Management Centre: Avenue Marnix 17, B1000 Brussels
© 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members.
Ref. No. EN 199914:2007/A1:2011: E
1
Contents
Page 
Foreword 
4 
National Annex for EN 199914 
6 
1 
General 
7 

1.1 
Scope 
7 


1.1.1 
Scope of EN 1999 
7 


1.1.2 
Scope of EN 199914 
7 

1.2 
Normative references 
8 


1.2.1 
General references 
8 


1.2.2 
References on structural design 
8 


1.2.3 
Materials and materials testing 
8 


1.2.4 
References on fasteners 
8 


1.2.5 
Other references 
8 

1.3 
Terms and definitions 
9 

1.4 
Symbols 
10 

1.5 
Geometry and conventions for dimensions 
10 


1.5.1 
Form of sections 
10 


1.5.2 
Form of stiffeners 
10 


1.5.3 
Crosssection dimensions 
11 


1.5.4 
Convention for member axis 
11 
2 
Basis of design 
12 
3 
Materials 
13 

3.1 
General 
13 

3.2 
Structural aluminium alloys 
13 


3.2.1 
Material properties 
13 


3.2.2 
Thickness and geometrical tolerances 
14 

3.3 
Mechanical fasteners 
15 
4 
Durability 
15 
5 
Structural analysis 
16 

5.1 
Influence of rounded corners 
16 

5.2 
Geometrical proportions 
17 

5.3 
Structural modelling for analysis 
17 

5.4 
Flange curling 
18 

5.5 
Local and distortional buckling 
19 


5.5.1 
General 
19 


5.5.2 
Plane crosssection parts without stiffeners 
19 


5.5.3 
Plane crosssection parts with intermediate stiffeners 
20 


5.5.4 
Trapezoidal sheeting profiles with intermediate stiffeners 
24 
6 
Ultimate limit states 
31 

6.1 
Resistance of crosssections 
31 


6.1.1 
General 
31 


6.1.2 
Axial tension 
31 


6.1.3 
Axial compression 
31 


6.1.4 
Bending moment 
32 


6.1.5 
Shear force 
34 


6.1.6 
Torsion 
35 


6.1.7 
Local transverse forces 
35 


6.1.8 
Combined tension and bending 
38 


6.1.9 
Combined compression and bending 
39 


6.1.10 
Combined shear force, axial force and bending moment 
39 


6.1.11 
Combined bending moment and local load or support reaction 
40 2 

6.2 
Buckling resistance 
40 


6.2.1 
General 
40 


6.2.2 
Axial compression 
41 


6.2.3 
Bending and axial compression 
41 

6.3 
Stressed skin design 
42 


6.3.1 
General 
42 


6.3.2 
Diaphragm action 
42 


6.3.3 
Necessary conditions 
43 


6.3.4 
Profiled aluminium sheet diaphragms 
44 

6.4 
Perforated sheeting with the holes arranged in the shape of equilateral triangles 
45 
7 
Serviceability limit states 
46 

7.1 
General 
46 

7.2 
Plastic deformation 
46 

7.3 
Deflections 
46 
8 
Joints with mechanical fasteners 
47 

8.1 
General 
47 

8.2 
Blind rivets 
48 


8.2.1 
General 
48 


8.2.2 
Design resistances of riveted joints loaded in shear 
48 


8.2.3 
Design resistances for riveted joints loaded in tension 
48 

8.3 
Selftapping / selfdrilling screws 
49 


8.3.1 
General 
49 


8.3.2 
Design resistance of screwed joints loaded in shear 
49 


8.3.3 
Design resistance of screwed joints loaded in tension 
50 
9 
Design assisted by testing 
52 
Annex A [normative] – Testing procedures 
53 

A.1 
General 
53 

A.2 
Tests on profiled sheets 
53 


A.2.1 
General 
53 


A.2.2 
Single span test 
54 


A.2.3 
Double span test 
54 


A.2.4 
Internal support test 
54 


A.2.5 
End support test 
56 

A.3 
Evaluation of test results 
57 


A.3.1 
General 
57 


A.3.2 
Adjustment of test results 
57 


A.3.3 
Characteristic values 
58 


A.3.4 
Design values 
59 


A.3.5 
Serviceability 
59 
Annex B [informative] – Durability of fasteners 
60 
Bibliography 
62 
3
Foreword
This European Standard (EN 199914:2007) has been prepared by Technical Committee CEN/TC250 « Structural Eurocodes », the secretariat of which is held by BS1.
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 August 2007, and conflicting national standards shall be withdrawn at the latest by March 2010.
This European Standard supersedes ENV 199911:1998, ENV 199912:1998 and ENV 19992:1998.
CEN/TC 250 is responsible for all Structural Eurocodes.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard:
Austria, Bulgaria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italia, Latvia, Lithuania, Luxemburg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom
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 agreement^{1} between the Commission and CEN, to transfer the preparation and the publication of the Eurocodes to the 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).
The Structural Eurocode programme comprises the following standards generally consisting of a number of Parts:
EN 1990 
Eurocode 0: 
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 
^{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).
4
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:
  as a means to prove compliance of building and civil engineering works with the essential requirements of Council Directive 89/106/EEC, particularly Essential Requirement No. 1 – Mechanical resistance and stability, and Essential Requirement No 2 – Safety in case of fire
  as a basis for specifying contracts for the execution of construction works and related engineering services
  as a framework for drawing up harmonised technical specifications for construction products (En’s and ETA’s)
The Eurocodes, as far as they concern the construction works themselves, have a direct relationship with the Interpretative Documents^{2} referred to in Article 12 of the CPD, although they are of a different nature from harmonised product standards^{3}. 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 full compatibility of these technical specifications with the Eurocodes.
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 [informative].
The National Annex (informative) 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.:
 – values for partial factors and/or classes where alternatives are given in the Eurocode;
 – values to be used where a symbol only is given in the Eurocode;
 – geographical and climatic data specific to the Member State, e.g. snow map;
 – the procedure to be used where alternative procedures are given in the Eurocode;
 – references to noncontradictory complementary information to assist the user to apply the Eurocode.
Links between Eurocodes and harmonised technical specifications (EN’s and ETA’s) for products
There is a need for consistency between the harmonised technical specifications for construction products and the technical rules for works^{4}. Furthermore, all the information accompanying the CE Marking of the
^{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:
 give concrete from to the essential requirements by harmonising the terminology and the technical bases and indicating classes or levels for each requirement where necessary;
 indicate methods of correlating these classes or levels of requirement with the technical specifications, e.g. methods of calculation and of proof, technical rule: for project design, etc.;
 serve as a reference for the establishment of harmonised standards and guidelines for European technical approvals.
The Eurocodes, de facto, play a similar role in the field of the ER 1 and a part of ER 2.
^{4} see Art.3.3 and Art. 12 of the CPD, as well clauses 4.2, 4.3.1, 4.3.2 and 5.2 of ID 1.
5
construction products which refer to Eurocodes shall clearly mention which Nationally Determined Parameters have been taken into account.
Foreword to amendment A1
This document (EN 19991 4:2007/A1:2011) has been prepared by Technical Committee CEN/TC 250 “Structural Eurocodes”, the secretariat of which is held by BSI.
This Amendment to the European Standard EN 199914:2007 shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by August 2012, and conflicting national standards shall be withdrawn at the latest by August 2012.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
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.
National Annex for EN 199914
This standard gives alternative procedures, values and recommendations for classes with notes indicating where national choices may have to be made. Therefore the National Standard implementing EN 19991 4 should have a National Annex containing all Nationally Determined Parameters to be used for the design of aluminium structures to be constructed in the relevant country.
National choice is allowed in EN 199914 through clauses:
 2(3)
 2(4)
 2(5)
 3.1(3)
 7.3(3)
 A.1(1)
 A.3.4(3)
6
1 General
1.1 Scope
1.1.1 Scope of EN 1999
 P EN 1999 applies to the design of buildings and civil engineering and structural works in aluminium. It complies with the principles and requirements for the safety and serviceability of structures, the basis of their design and verification that are given in EN 1990 – Basis of structural design.
 EN 1999 is only concerned with requirements for resistance, serviceability, durability and fire resistance of aluminium structures. Other requirements, e.g. concerning thermal or sound insulation, are not considered.
 EN 1999 is intended to be used in conjunction with:
 – EN 1990 “Basis of structural design”
 – EN 1991 “Actions on structures”
 – European Standards construction products relevant for aluminium structures
 – EN 10901: Execution of steel structures and aluminium structures – Part 1: Requirements for conformity assessment of structural components^{5}
 – EN 10903: Execution of steel structures and aluminium structures – Part 3: Technical requirements for aluminium structures^{5}
 EN 1999 is subdivided in five parts:
EN 199911 
Design of Aluminium Structures: General structural rules. 
EN 199912 
Design of Aluminium Structures: Structural fire design. 
EN 199913 
Design of Aluminium Structures: Structures susceptible to fatigue. 
EN 199914 
Design of Aluminium Structures: Coldformed structural sheeting. 
EN 199915 
Design of Aluminium Structures: Shell structures. 
1.1.2 Scope of EN 199914
 P EN 199914 gives design requirements for coldformed trapezoidal aluminium sheeting. It applies to coldformed aluminium products made from hot rolled or cold rolled sheet or strip that have been coldformed by such processes as coldrolled forming or pressbreaking. The execution of aluminium structures made of coldformed sheeting is covered in EN 10903.
NOTE The rules in this part complement the rules in other parts of EN 19991.
 Methods are also given for stressedskin design using aluminium sheeting as a structural diaphragm.
 This part does not apply to coldformed aluminium profiles like C, Z etc profiles nor coldformed and welded circular or rectangular hollow sections.
 EN 199914 gives methods for design by calculation and for design assisted by testing. The methods for the design by calculation apply only within stated ranges of material properties and geometrical properties for which sufficient experience and test evidence is available. These limitations do not apply to design by testing.
 EN 199914 does not cover load arrangement for loads during execution and maintenance.
^{5} To be published
7
1.2 Normative references
 The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
1.2.1 General references
EN 10901: 
Execution of steel structures and aluminium structures – Part 1: Requirements for conformity assessment of structural components^{6} 
EN 10903: 
Execution of steel structures and aluminium structures – Part 3: Technical requirements for aluminium structures^{6} 
1.2.2 References on structural design
EN 1990 
Eurocode 0  Basis of structural design 
EN 1991 
Eurocode 1 – Action on structures – All parts 
EN 199511 
Eurocode 5: Design of timber structures  Part 11 General rules and rules for buildings 
EN 199911 
Eurocode 9: Design of aluminium structures  Part 11 General structural rules 
1.2.3 Materials and materials testing
EN 4852:2008 
Aluminium and aluminium alloys  Sheet, strip and plate  Part 2: Mechanical properties 
EN 5082 
Roofing products from metal sheet  Specification for selfsupporting products of steel, aluminium or stainless steel sheet  Part 2: Aluminium 
EN 1396:2007 
Aluminium and aluminium alloys  Coil coated sheet and strip for general applications  Specifications 
EN 100021 
Metallic materials  Tensile testing  Part 1: Method of test at ambient temperature 
Text deleted 

1.2.4 References on fasteners
EN ISO 1479 
Hexagon head tapping screws 
EN ISO 1481 
Slotted pan head tapping screws 
EN ISO 15480 
Hexagon washer head drilling screws with tapping screw thread 
EN ISO 15481 
Cross recessed pan head drilling screws with tapping screw thread 
EN ISO 15973 
Closed end blind rivets with break pull mandrel and protruding head 
EN ISO 15974 
Closed end blind rivets with break pull mandrel and countersunk head 
EN ISO 15977 
Open end blind rivets with break pull mandrel and protruding head 
EN ISO 15978 
Open end blind rivets with break pull mandrel and countersunk head 
EN ISO 15981 
Open end blind rivets with break pull mandrel and protruding head 
EN ISO 15982 
Open end blind rivets with break pull mandrel and countersunk head 
ISO 7049:1994 
Cross recessed pan head tapping screws 
1.2.5 Other references
EN ISO 129442 
Paints and varnishes  Corrosion protection of steel structures by protective paint systems  Part 2: Classification of environments 
^{6} To be published
8
1.3 Terms and definitions
Supplementary to EN 199911, for the purposes of EN 199914, the following definitions apply:
1.3.1
base material
the flat sheet aluminium material out of which profiled sheets are made by cold forming
1.3.2
proof strength of base material
the 0,2 % proof strength f_{o} of the base material
1.3.3
diaphragm action
structural behaviour involving inplane shear in the sheeting
1.3.4
partial restraint
restriction to some extent of the lateral or rotational displacement of a crosssection part, that increases its buckling resistance
1.3.5
restraint
full restriction of the lateral displacement or rotational movement of a plane crosssection part, that increases its buckling resistance
1.3.6
slenderness parameter
a normalised, material related slenderness ratio
1.3.7
stressedskin design
a design method that allows for the contribution made by diaphragm action in the sheeting to the stiffness and strength of a structure
1.3.8
support
a location at which a member is able to transfer forces or moments to a foundation, or to another structural component.
1.3.9
effective thickness
a design value of the thickness to allow for local buckling of plane cross section part.
1.3.10
reduced effective thickness
a design value of the thickness to allow for distortional buckling of stiffeners in a second step of the calculation procedure for plane cross section parts, where local buckling is allowed for in the first step.
9
1.4 Symbols
 In addition to those given in EN 199911, the following main symbols are used:
Section 1 to 6
C 
rotational spring stiffness; 
k 
linear spring stiffness; 
θ 
rotation; 
b_{p} 
notional flat width of plane crosssection part; 
h_{w} 
web height, measured between system lines of flanges; 
s_{w} 
slant height of web, measured between midpoints of comers; 
χ_{d} 
reduction factor for distortional buckling (flexural buckling of stiffeners); 
φ 
is the angle between two plane elements; 
ϕ 
is the slope of the web relative to the flanges. 
Section 8 Joints with mechanical fasteners
d_{w} 
diameter of the washer or the head of the fastener; 
f_{u,min} 
minor ultimate tensile strength of both connected parts; 
f_{u,sup} 
ultimate tensile strength of the supporting component into which a screw is fixed; 
f_{y} 
yield strength of supporting component of steel; 
t_{min} 
thickness of the thinner connected part or sheet; 
t_{sup} 
thickness of the supporting member in which the screw is fixed; 
 Further symbols arc defined where they first occur.
1.5 Geometry and conventions for dimensions
1.5.1 Form of sections
 Coldformed sheets have within the permitted tolerances a constant thickness nominal over their entire length and have a uniform crosssection along their length.
 The crosssections of cold formed profiled sheets essentially comprise a number of plane crosssection parts joined by curved parts.
 Typical forms of crosssections for cold formed profiled sheets are shown in Figure 1.1.
 Crosssections of cold formed sheets can either be unstiffened or incorporate longitudinal stiffeners in their webs or flanges, or in both.
1.5.2 Form of stiffeners
 Typical forms of stiffeners for cold formed sheets are shown in Figure 1.2;
10
Figure 1.1  Examples of coldformed sheeting
Figure 1.2  Typical intermediate longitudinal stiffeners
1.5.3 Crosssection dimensions
 Overall dimensions of coldformed sheeting, including overall width b, overall height h, internal bend radius r and other external dimensions denoted by symbols without subscripts, are measured to the outer contour of the section, unless stated otherwise, see Figure 5.1.
 Unless stated otherwise, the other crosssectional dimensions of coldformed sheeting, denoted by symbols with subscripts, such as b_{p}, h_{w} or s_{w}, are measured either to the midline of the material or the midpoint of the corner.
 In the case of sloping webs of coldformed profiled sheets, the slant height s is measured parallel to the slope.
 The developed height of a web is measured along its midline, including any web stiffeners.
 The developed width of a flange is measured along its midline, including any intermediate stiffeners.
 The thickness t is an aluminium design thickness if not otherwise stated. Sec 3.2.2.
1.5.4 Convention for member axis
 For profiled sheets the following axis convention is used in EN 199914:
  yy axis parallel to the plane of sheeting;
  zz axis perpendicular to the plane of sheeting.
11
2 Basis of design
 P The design of coldformed sheeting shall be in accordance with the general rules given in EN 1990 and EN 199911.
 P Appropriate partial factors shall be adopted for ultimate limit states and serviceability limit states.
 For verification by calculation at ultimate limit states the partial factor γ_{M} shall be taken as follows:
 
resistance of crosssections and members to instability: 
γ_{M1} 
 
resistance of crosssections in tension to fracture: 
γ_{M2} 
 
resistance of joints: 
γ_{M3} 
NOTE Numerical values for γ_{Mi} may be defined in the National Annex. The following numerical values are recommended for buildings:
γ_{M1} = 1,10
γ_{M2} = 1,25
γ_{M3} = 1,25
 For verifications at serviceability limit states the partial factor γ_{M,ser} should be used.
NOTE Numerical values for γ_{M,ser} may be defined in the National Annex. The following numerical value is recommended for buildings:
γ_{M,ser} = 1,0.
 For the design of structures made of coldformed sheeting a distinction should be made between “Structural Classes” dependent on its function in the structure defined as follows:
Structural Class I: 
Construction where coldformed sheeting is designed to contribute to the overall strength and stability of the structure, see 6.3.3; 
Structural Class II: 
Construction where coldformed sheeting is designed to contribute to the strength and stability of individual structural components; 
Structural Class III: 
Construction where coldformed sheeting is used as a component that only transfers loads to the structure. 
NOTE 1 National Annex may give rules for the use of Structural Classes and the connection to Consequence Classes in EN 1990.
NOTE 2 For Structural Class I and II the requirement for execution should be given in the execution specification, see EN 10903
12
3 Materials
3.1 General
 The methods for design by calculation given in EN 199914 may be used for the structural alloys in the tempers listed in table 3.1.
 For design by calculation given in EN 199914 the 0,2 proof strength f_{o} should be at least f_{o} = 165 N/mm^{2}.
 Aluminium sheet and strip used for coldformed profile sheeting should be suitable for the specific cross section depending on cold forming and cold forming process.
NOTE For other aluminium materials and products see National Annex.
3.2 Structural aluminium alloys
3.2.1 Material properties
 The characteristic values of 0,2 proof strength f_{o} and tensile strength f_{u} have been obtained by adopting the values for minimum R_{p0,2} and R_{m} direct from the relevant product standards.
 It may be assumed that the properties in compression are the same as those in tension.
 If partially plastic moment resistance is utilised, the ratio of the characteristic ultimate tensile strength f_{u} to the characteristic 0,2 proof strength f_{o} should be not less than 1,2.
 The material constants (modulus of elasticity etc) should be taken as given in EN 19991 1.
13
Table 3.1  Characteristic values of 0,2% proof strength f_{o}, ultimate tensile strength, f_{u}, elongation A_{50}, for sheet and strip for tempers with f_{o} > 165 N/mm^{2} and thickness between 0,5 and 6 mm
Designation numerical EN AW 
Designation chemical EN AW 
Durability rating ^{5)} 
Temper ^{1), 2), 3)} 
Thickness up to mm 
f_{u} R_{m} N/mm^{2} 
f_{o} R_{p0,2} ^{1)} N/mm^{2} 
A_{50} % ^{4)} 
3003 
AlMn1Cu 
A 
H18 
3,0 
190 
170 
2 
H48 
3,0 
180 
165 
2 
3004 
AlMn1Mg1 
A 
H14  H24/H34 
6  3 
220 
180  170 
23  4 
H16  H26/H36 
4  3 
240 
200 190 
12  3 
H18  H28/H38 
3  1,5 
260 
230220 
12  3 
H44 
3 
210 
180 
4 
H46 
3 
230 
200 
3 
H48 
3 
260 
220 
3 
3005 
AlMn1Mg0,5 
A 
H16 
4 
195 
175 
2 
H18  H28 
3 
220 
200  190 
2  23 
H48 
3 
210 
180 
2 
3103 
AlMn1 
A 
H18 
3 
185 
165 
2 
3105 
AlMn0,5Mg0,5 
A 
H18  H28 
3  1,5 
195 
180  170 
1  2 
H48 
3 
195 
170 
2 
5005 
AlMg1(B) 
A 
H18 
3 
185 
165 
2 
5052 
AlMg2,5 
A 
H14 
6 
230 
180 
34 
H16  H26/H36 
6 
250 
210  180 
3  46 
H18  H28/H38 
3 
270 
240  210 
2  34 
H46 
3 
250 
180 
45 
H48 
3 
270 
210 
34 
5251 
AlMg2Mn0,3 
A 
H14 
6 
210 
170 
24 
H16  H26/H36 
4 
230 
200  170 
23  47 
H18  H28/H38 
3 
255 
230  200 
2  3 
H46 
3 
210 
165 
45 
H48 
3 
250 
215 
3 
60257072 alclad^{6)} 
AlMg2,5SiMnCuAlZnl alclad^{6)} 
A 
H34 
5 
210 
165 
23 
H36 
5 
220 
185 
24 
1) The values for temper H1x, H2x, H3x according to EN 4852:2008
2) The values for temper H4x (coil coated sheet and strip) according EN 1396:2007
3) If two (three) tempers are specified in one line, tempers separated by “” have different technological values, but separated by “/” have same values. (The tempers show differences only for f_{o} and A_{50}.)
4) A_{50} may be depending on the thickness of material in the listed range, therefore sometimes also a A_{50} range is given.
5) Durability rating, see EN 199911
6) EN AW60257072 alclad (EN AWAlMg2,5SiMnCuAlZnl alclad) is a composite material with core material EN AW6025 and a cladding on both sides with EN AW7072. For reasons of durability the cladding should have a thickness of at least 4% of the overall thickness of the material on each side. If the thickness of the cladding exceeds 5% this fact should be considered in the structural calculations, i.e. only the core thickness of the composite sheet should be taken in account. For these reasons the minimum cladding thickness of 4% and the minimum core thickness should be specified in the execution specification in order that the constructor can procure the corresponding constituent products with inspection certificate 3.1.

14
3.2.2 Thickness and geometrical tolerances
 The provisions for design by calculation given in this EN 199914 may be used for alloy within the following ranges of nominal thickness t_{nom} of the sheeting exclusive of organic coatings:
t_{nom} ≥ 0,5 mm
 The nominal thickness t_{nom} should be used as design thickness t if a negative deviation is less than 5 %. Otherwise
t = t_{nom} (100 − dev) / 95 (3.1)
where dev is the negative deviation in %.
 Tolerances for roofing products are given in EN 5082.
3.3 Mechanical fasteners
 The following types of mechanical fasteners may be used:
  selftapping screws as threadforming selftapping screws or selfdrilling selftapping screws according to standards listed in 8.3;
  blind rivets according to standards listed in 8.2.
 The characteristic shear resistance F_{v,Rk} and the characteristic tension resistance F_{t,Rk} of the mechanical fasteners should be calculated according to 8.2 and 8.3.
 For details concerning suitable selftapping screws, and selfdrilling screws and blind rivets, reference should be made to EN 10903.
 Characteristic shear resistance and characteristic tension resistance of mechanical fasteners not covered in this European Standard may be taken from ETA certifications.
4 Durability
 For basic requirements, see Section 4 of EN 199911
 Special attention should be given to cases in which different materials are intended to act compositely, if these materials are such that electrochemical phenomena might produce conditions leading to corrosion.
NOTE For corrosion resistance of fasteners for the environmental corrosivity categories following EN ISO 129442, see Annex B.
 The environmental conditions prevailing from the time of manufacture, including those during transport and storage on site, should be taken into account.
15
5 Structural analysis
5.1 Influence of rounded corners
 In crosssections with rounded corners, the notional flat widths b_{p} of the plane crosssection parts should be measured from the midpoints of the adjacent corner crosssection parts, as indicated in Figure 5.1.
 In crosssections with rounded corners, the calculation of section properties should be based upon the actual geometry of the crosssection.
 Unless more appropriate methods are used to determine the section properties the following approximate procedure may be used. The influence of rounded corners on section properties may be neglected if the internal radius r ≤ 10t and r ≤ 0,15b_{p} and the crosssection may be assumed to consist of plane crosssection parts with sharp corners.
 The influence of rounded corners on section properties may be taken into account by reducing the properties calculated for an otherwise similar crosssection with sharp corners, using the following approximations:
A_{g} ≈ A_{g,sh} (1 − δ) (5.1a)
I_{g} ≈ I_{g,sh} (1 − 2δ) (5.1b)
with:
where:
A_{g} 
is the area of the gross crosssection; 
A_{g,sh} 
is the value of A_{g} for a crosssection with sharp corners; 
b_{p,i} 
is the notional flat width of plane crosssection part i for a crosssection with sharp corners; 
I_{g} 
is the second moment of area of the gross crosssection; 
I_{g,sh} 
is the value of I_{g} for a crosssection with sharp corners; 
φ 
is the angle between two plane elements; 
m 
is the number of plane crosssection parts; 
n 
is the number of curved crosssection parts without consideration of the curvature of stiffeners in webs and flanges; 
r_{j} 
is the internal radius of curved crosssection part. 
 The reductions given by expression (5.1) may also be applied in calculating the effective section properties A_{eff} and I_{y,eff} provided that the notional flat widths of the plane crosssection parts are measured to the points of intersection of their midlines.
 Where the internal radius r ≥ 0,04tE / f_{o}, then the resistance of the crosssection should be determined by tests.
16
Figure 5.1  Notional widths of plane crosssection parts b_{p} allowing for corner radii
5.2 Geometrical proportions
 The provisions for design by calculation given in EN 199914 should not be applied to crosssections outside the range of widthtothickness ratios b / t and s_{w} / t given in (2).
 The maximum widthtothickness ratios are:
• 
for compressed flanges 
b / t ≤ 300 
• 
for webs 
s_{w} / t ≤ 0,5 E / f_{o} 
NOTE These limits b / t and s_{w} / t given in (2) may be assumed to represent the field for which sufficient experience and verification by testing is available. Crosssections with larger widthtothickness ratios may also be used, provided that their resistance at ultimate limit states and their behaviour at serviceability limit states are verified by testing and/or by calculations, where the results are confirmed by an appropriate number of tests.
5.3 Structural modelling for analysis
 The parts of a crosssection may be modelled for analysis as indicated in Table 5.1
 The mutual influence of multiple stiffeners should be taken into account.
17
Table 5.1  Modelling of parts of a crosssection
Type of crosssection part 
Model 
Type of crosssection part 
Model 








5.4 Flange curling
 The effect on the load bearing resistance of curling (i.e. inward curvature towards the neutral plane) of a very wide flange in a profile subject to flexure, or of an initially curved profile subject to flexure in which the concave side is in compression, should be taken into account unless such curling is less than 5 % of the depth of the profile crosssection. If curling is larger, then the reduction in load bearing resistance, for instance due to decrease in length of the lever arm for part of the wide flange, and to the possible effect of bending should be taken into account.
Figure 5.2  Flange curling
 Calculation of the curling may be carried out as follows. The formulae apply to both compression and tensile flanges, both with and without stiffeners, but without closely spaced transverse stiffeners in flanges.
  For a profile, which is straight prior to application of loading, see Figure 5.2:
  For an initially curved profile
where:
u 
is bending of the flange towards the neutral axis (curling), see Figure 5.2; 
b_{s} 
is half the distance between the webs; 
z 
is distance of flange under consideration from neutral axis; 
r 
is radius of curvature of initially curved profile; 
σ_{a} 
is mean stress in the flange calculated with the gross area. If the stress is calculated for the effective crosssection, the mean stress is obtained by multiplying the stress for the effective crosssection by the ratio of the effective flange area to the gross flange area. 
18
5.5 Local and distortional buckling
5.5.1 General
 The effects of local and distortional buckling should be taken into account in determining the resistance and stiffness of coldformed sheeting.
 Local buckling effects may be considered by using effective crosssectional properties, calculated on the basis of the effective thickness, see EN 199911.
 In determining resistance to local buckling, the 0,2 proof strength f_{o} should be used.
 For effective crosssection properties for serviceability verifications, see 7.1 (3)
 The distortional buckling of crosssection parts with intermediate stiffeners is considered in 5.5.3.
5.5.2 Plane crosssection parts without stiffeners
 The effective thickness t_{eff} of compression crosssection parts should be obtained as t_{eff} = ρ · t, where ρ is a reduction factor allowing for local buckling.
 The notional flat width b_{p} of a plane crosssection part should be determined as specified in 5.1. In the case of plane crosssection parts in a sloping web, the appropriate slant height should be used.
 The reduction factor ρ to determine t_{eff} should be based on the largest compressive stress σ_{com,Ed} relevant crosssection part (calculated on the basis of the effective crosssection), when the resistance of the crosssection is reached.
 If σ_{com,Ed} = f_{0} / γ_{M1} the reduction factor ρ should be obtained from the following:
in which the plate slenderness is given by:
k_{σ} is the relevant buckling factor from Table 5.3. The parameters and α may be taken from Table 5.2.
Table 5.2  Parameters λ_{lim} and α

α 
0,517 
0,90 
 If σ_{com,Ed} < f_{o} / γ_{M1} the reduction factor ρ may be determined as follows:
Use expressions (5.2a) and (5.2b) but replace the plate slenderness by the reduced plate slenderness given by:
19
 For calculation of effective stiffness at serviceability limit states, see 7.1(3)
 In determining the effective thickness of a flange crosssection part subject to stress gradient, the stress ratio ψ used in Table 5.3 may be based on the properties of the gross crosssection.
 In determining the effective thickness of a web crosssection part the stress ratio ψ used in Table 5.3 may be obtained using the effective area of the compression flange but the gross area of the web.
 Optionally the effective section properties may be refined by repeating (6) and (7) iteratively, but using the effective crosssection already found in place of the gross crosssection. The minimum steps in the iteration dealing with stress gradient are two.
Table 5.3  Buckling coefficient k_{σ} for crosssection parts in compression
Crosssection part (+ = compression) 
ψ = σ_{2} / σ_{1} 
Buckling factor k_{σ} 

ψ = + 1 
k_{σ} = 4,0 

+ 1 > ψ ≥ 0 


0 > ψ ≥ −1 
k_{σ} = 7,81 − 6,26ψ + 9,78ψ^{2} 

−1 > ψ ≥ −3 
k_{σ} = 5,98(1 − ψ)^{2} 
5.5.3 Plane crosssection parts with intermediate stiffeners
5.5.3.1 General
 The design of compression crosssection parts with intermediate stiffeners should be based on the assumption that the stiffener behaves as a compression member with continuous partial restraint, with a spring stiffness that depends on the boundary conditions and the flexural stiffness of the adjacent plane crosssection parts.
 The spring stiffness of a stiffener should be determined by applying a unit load per unit length u as illustrated in Figure 5.3. The spring stiffness k per unit length may be determined from:
k = u / δ (5.5)
where δ is the deflection of a transverse plate strip due to the unit load u acting at the centroid (b_{1}) of the effective part of the stiffener.
20
Figure 5.3  Model for determination of spring stiffness
 In determining the values of the rotational spring stiffness C_{θ,1} and C_{θ,2} from the geometry of the crosssection, account should be taken of the possible effects of other stiffeners that exist on the same crosssection part, or on any other parts of the crosssection that is subject to compression.
 For an intermediate stiffener, as a conservative alternative, the values of the rotational spring stiffnesses C_{θ,1} and C_{θ,2} may be taken as equal to zero, and the deflection δ may be obtained from:
 The reduction factor χ_{d} distortional buckling resistance of a stiffener (flexural buckling of an intermediate stiffener) should be obtained from Table 5.4 for the slenderness parameter given in (5.7)
where: σ_{cr,s} is the elastic critical stress for the stiffener from 5.5.3.3 or 5.5.4.2.
Table 5.4  Reduction factory χ_{d} for distortional buckling of stiffeners

χ_{d} 
≤ 0,25 
1,00 
0,25 < < 1,04 
1,155 − 0,62 
1,04 ≤ 
0,53/ 
5.5.3.2 Condition for use of the design procedure
 The following procedure is applicable to one or two equal intermediate stiffeners formed by grooves or bends provided that all plane parts are calculated according to 5.5.2.
 The stiffeners should be equally shaped and not more than two in number. For more stiffeners not more than two should be taken into account.
 If the criteria in (1) and (2) are met the effectiveness of the stiffener may be determined from the design procedure given in 5.5.3.3.
21
5.5.3.3 Design procedure
 The crosssection of an intermediate stiffener should be taken as comprising the stiffener itself plus the adjacent effective portions of the adjacent plane crosssection parts b_{p,1} and b_{p,2} shown in Figure 5.4.
Figure 5.4 – Initial effective crosssection area A_{s} for intermediate stiffeners in (a) flange and (b) web
 The procedure, which is illustrated in Figure 5.5, should be earned out in steps as follows:
  Step 1: Obtain an initial effective crosssection for the stiffener to calculate the crosssection area A_{s} using effective thickness determined by assuming that the stiffener is longitudinally supported and that σ_{com,Ed} = f_{o}/γ_{M1}, see (3) and (4);
  Step 2: Use another effective crosssection of the stiffener to calculate the effective second moment of inertia in order to determine the reduction factor for distortional buckling, allowing for the effects of the continuous spring restraint, see (5) and (6);
  Step 3: Optionally iterate to refine the value of the reduction factor for buckling of the stiffener, see (7) and (8).
22
Figure 5.5 – Model for calculation of compression resistance of a flange with intermediate stiffener
 Initial values of the effective thickness t_{eff,1} and t_{eff,2} shown in Figure 5.4 should be determined from 5.5.2 by assuming that the plane crosssection parts b_{p,1} and b_{p,2} are doubly supported, see Table 5.1.
 The effective crosssectional area of an intermediate stiffener A_{s} should be obtained from:
A_{s} = t_{eff,1} b_{p,1} / 2 + t b_{s} + t_{eff,2} b_{p,2} / 2 (5.8)
23
in which the stiffener width b_{s} is as shown in Figure 5.4.
 The critical buckling stress σ_{cr,s} for an intermediate stiffener should be obtained from:
where:
k 
is the spring stiffness per unit length, see 5.5.3.1(2); 
I_{s} 
is the effective second moment of area of the stiffener, using the thickness t and notional effective width 12t of adjacent plane crosssection parts about the centroidal axis a  a of its effective crosssection, see Figure 5.6(a). 
 The reduction factor χ_{d} for the distortional buckling resistance of an intermediate stiffener should be obtained from the value of σ_{cr,s} using the method given in 5.5.3.1(5).
 If χ_{d} < 1 it may optionally be refined iteratively, starting the iteration with modified values of ρ obtained using 5.5.2(4) with σ_{com,Ed} equal to χ_{d} f_{o}/γ_{M1}, so that:
 If iteration is carried out, it should be continued until the current value of χ_{d} is approximately equal to, but not more than, the previous value.
 The reduced effective area of the stiffener A_{s,red} allowing for distortional buckling should be taken as:
where σ_{com,Ed} is compression stress at the centreline of the stiffener calculated on the basis of the effective crosssection.
 In determining effective section properties, the reduced effective area A_{s,red} should be represented by using a reduced thickness t_{red} = χ_{d} t_{eff} for all the crosssection parts included A_{s}
5.5.4 Trapezoidal sheeting profiles with intermediate stiffeners
5.5.4.1 General
 This subclause should be used in association with 5.5.3.3 for flanges with intermediate flange stiffeners and for webs with intermediate stiffeners.
 Interaction between distortional buckling of intermediate flange stiffeners and intermediate web stiffeners should also be taken into account using the method given in 5.5.4.4.
5.5.4.2 Flanges with intermediate stiffeners
 If it is subject to uniform compression, the effective crosssection of a flange with intermediate stiffeners should be assumed to consist of the reduced effective areas A_{s,red} of up to two intermediate stiffeners and two strips of width 0,5b_{p} and thickness t_{eff} adjacent to the edges supported by webs, see Figure 5.5f). 24
 For one central flange stiffener, the elastic critical buckling stress σ_{cr,s} should be obtained from:
where:
b_{p} 
is the notional flat width of plane crosssection part shown in Figure 5.6; 
b_{s} 
is the stiffener width, measured around the perimeter of the stiffener, see Figure 5.6(c); 
k_{w} 
is a coefficient that allows for partial rotational restraint of the stiffened flange by the webs, see (5) and (6); 
and A_{s} and I_{s} are as defined in 5.5.3.3 and Figure 5.6. 
Figure 5.6 – Effective cross section for calculation of I_{s} and A_{s} for compression flange with two or one stiffener
 For two symmetrically placed flange stiffeners, the elastic critical buckling stress σ_{cr,s} should be obtained from:
with:
b_{e} = 2b_{p,1} + b_{p,2} + 2b_{s}
b_{1} = b_{p,1} + 0,5 b_{r}
where:
b_{p,1} 
is the notional flat width of an outer plane crosssection part, as shown in Figure 5.6; 
b_{p,2} 
is the notional flat width of the central plane crosssection part, as shown in Figure 5.6; 
b_{s} 
is the stiffener width, measured around the perimeter of the stiffener, see Figure 5.6(c). 
 If there are three stiffeners, the one in the middle should be assumed to be ineffective.
 The value of k_{w} may be calculated from the compression flange buckling wavelength l_{b} as follows:
  if l_{b}/s_{w} ≥ 2: κ_{w} = κ_{wo} (5.14a)
  if l_{b}/s_{w} ≥ 2: κ_{w} = κ_{wo} − (κ_{wo} − 1)[2l_{b}/s_{w} − (l_{b}/s_{w})^{2}] (5.14b)
where:
s_{w} 
is the slant height of the web, see Figure 5.7(a). 25 
l_{b} 
half wavelength for elastic buckling of stiffener, see (7). 
 Alternatively, the rotational restraint coefficient κ_{w} may conservatively be taken as equal to 1,0 corresponding to a pinjointed condition.
 The values of l_{b} and κ_{wo} may be determined from the following:
  for a compression flange with one intermediate stiffener:
with:
b_{d} = 2b_{p} + b_{s}
  for a compression flange with two or three intermediate stiffeners:
 The reduced effective area of the stiffener A_{s,red} allowing for distortional buckling (flexural buckling of an intermediate stiffener) should be taken as:
 If the webs are unstiffened, the reduction factor χ_{d} should be obtained directly from σ_{cr,s} using the method given in 5.5.3.1(5).
 If the webs are also stiffened, the reduction factor χ_{d} should be obtained using the method given in 5.5.3.1(5), but with the modified elastic critical stress σ_{cr,mod} given in 5.5.4.4.
 In determining effective section properties, the reduced effective area A_{s,red} should be represented by using a reduced thickness t_{red} = χ_{d} t_{eff} for all the crosssection parts included in A_{s}.
5.5.4.3 Webs with up to two intermediate stiffeners under stress gradient
 The effective crosssection of the compressed zone of a web should be assumed to consist of the reduced effective areas, A_{s,red} of up to two intermediate stiffeners, a strip adjacent to the compression flange and a strip adjacent to the centroidal axis of the profile crosssection, see Figure 5.7. Webs under uniform compression stress should be treated analogously to stiffened flanges.
 The effective crosssection of a web as shown in Figure 5.7 should be taken to include:
 a strip of width s_{a}/2 and effective thickness t_{eff,a} adjacent to the compression flange;
 the reduced effective area A_{s,red} of each web stiffener up to a maximum of two;
 a strip of width 2s_{n}/3 adjacent to the effective centroidal axis;
26
 the part of the web in tension.
Figure 5.7  Effective crosssections of webs of coldformed profiled sheets
 The initial effective areas should be obtained from the following:
  for a single stiffener:
  for the stiffener closer to the compression flange in webs with two stiffeners:
  for a second stiffener
in which the dimensions s_{a}, s_{sa}, s_{b}, s_{sb}, and s_{n} are as shown in Figure 5.7 and t_{eff,a}, t_{eff,b} and t_{eff,n} are given in (5).
 Initially the location of the effective centroidal axis should be based on the effective area of the flanges but with the gross area of the webs.
 If the slenderness of the part of the web which is in compression is larger than (see 5.5.2(4)), the effective thickness t_{teff,a}, t_{teff,b} and t_{teff,n} should be determined as follows:
t_{eff} = ρ t (5.22)
27
where ρ is calculated using expression (5.2) with slenderness and stress relation factor ψ according to Table 5.5, where e_{c} and e_{t} are the distances from the effective centroidal axis to the system line of the compression and tension flange, see Figure 5.7, and the dimensions h_{a}, h_{b}, h_{sa}, h_{sb}, s_{n} and ϕ are as shown in Figure 5.7.
 To calculate the initial effective area A_{sa} and A_{sb} of web stiffeners, s_{a} and s_{b} are divided into two equal parts s_{a}/2 and s_{b}/2. The web part s_{n} over the centroidal axis is divided into one part s_{n}/3 adjacent to the stiffener, Figure 5.7 (dl) and (d3), and one part 2s_{n}/3 adjacent to the centroidal axis.
 For a single stiffener, or for the stiffener closer to the compression flange in webs with two stiffeners, the elastic buckling stress s_{cr,sa} should be determined using:
in which s_{1} and s_{2} are given by the following:
  for a single stiffener:
s_{1} = 0,9(s_{a} + s_{sa} + s_{c}), s_{2} = s_{1} – s_{a} – 0,5 s_{sa} (5.24)
  for the stiffener closer to the compression flange, in webs with two stiffeners where the other stiffener is in tension or close to the centroidal axis:
s_{1} = s_{a} + s_{sa} + s_{b} + 0,5(s_{sb} + s_{c}), s_{2} = s_{1} – s_{a} – 0,5 s_{sa} (5.25)
where:
κ_{f} 
is a coefficient that allows for partial rotation restraint of the stiffened web by the flanges; 28 
I_{sa} 
is the second moment of area of a stiffener crosssection comprising the fold, width s_{sa}, and two adjacent strips, each of width 12t, about its own centroidal axis parallel to the plane web crosssection parts, see Figure 5.7(e). In calculating I_{sa} the possible difference in slope between the plane crosssection parts on either side of the stiffener may be neglected. 
 In the absence of a more detailed investigation, the rotational restraint coefficient κ_{f} may conservatively be taken as equal to 1,0 corresponding to a pinjointed condition.
 For a single stiffener in compression, or for the stiffener closer to the compression flange in a web with two stiffeners, the reduced effective area A_{sa,red} (Step 2 in Figure 5.5) should be determined from:
 If the flanges are also stiffened, the reduction factor χ_{d} should be obtained using the method given in 5.5.3.1(5), but with the modified elastic critical stress σ_{cr,mod} given in 5.5.4.4.
 For a single stiffener in tension, the reduced effective area A_{sa,red} should be taken as equal to A_{sa}.
 For webs with two stiffeners, the reduced effective area A_{sb,red} the second stiffener, close to the neutral axis, should be taken as equal to A_{sb}
 In determining effective section properties, the reduced effective area A_{sa,red} should be represented by using a reduced thickness t_{red} = χ_{d} t_{eff} for all the crosssection parts included in A_{sa}.
 If χ_{d} < 1 it may optionally be refined iteratively, see 5.5.3(7).
 For the effective section properties at serviceability limit states, see 7.1.
5.5.4.4 Sheeting with flange stiffeners and web stiffeners
 (1) In the case of sheeting with intermediate stiffeners in the flanges and in the webs, see Figure 5.8, interaction between the distortional buckling of the flange stiffeners and the web stiffeners should be allowed for by using a modified elastic critical stress σ_{Cr,mod} for both types of stiffeners, obtained from:
where:
σ_{cr,s} 
is the elastic critical stress for an intermediate flange stiffener, see 5.5.4.2(2) for a flange with a single stiffener or 5.5.4.2(3) for a flange with two stiffeners; 
σ_{cr,sa} 
is the elastic critical stress for a single web stiffener, or the stiffener closer to the compression flange in webs with two stiffeners, see 5.5.4.3(7). 
β_{s} = 1 – (h_{a} + 0,5h_{sa}) / e_{c} 
for a profile in bending 
β_{s} = 1 
for a profile in axial compression 
29
Figure 5.8 – Effective cross section of coldformed profiled sheeting with flange stiffeners and web stiffeners
30
6 Ultimate limit states
6.1 Resistance of crosssections
6.1.1 General
 The rules in this section apply to the design by calculation.
 Design assisted by testing may be used instead of design by calculation for any resistance, see Section 9 and Annex A.
NOTE Design assisted by testing is particularly likely to be beneficial for cross sections with relatively high b_{p}/t ratios, e.g. in relation to inelastic behaviour, web crippling or shear lag.
 For design by calculation, the effects of local buckling and distortional buckling should be taken into account by using effective section properties determined as specified in 5.5.
 The buckling resistance of sheeting members in compression should be verified as specified in 6.2.
6.1.2 Axial tension
 The design resistance of a crosssection for uniform tension N_{t,Rd} should be determined from:
where:
A_{g} 
is the gross area of the crosssection; 
F_{net,Rd} 
is the netsection resistance for the appropriate type of mechanical fastener. 
6.1.3 Axial compression
 The design resistance of a crosssection for compression N_{c,Rd} should be determined from:
  if the effective area A_{eff} is less than the gross area A_{g} (section with reduction due to local and/or distortional buckling)
N_{c,Rd} = A_{eff} f_{o} / γ_{M1} (6.2)
  if the effective area A_{eff} is equal to the gross area A_{g} (section with no reduction due to local or distortional buckling)
N_{c,Rd} = A_{g} f_{o} / γ_{M1} (6.3)
where:
A_{eff} is the effective area of the crosssection, obtained from 5.5.2 by assuming a uniform compressive stress equal to f_{o} / γ_{M1}.
 The internal normal force in a member should be taken as acting at the centroid of its gross crosssection. This is a conservative assumption, but can be used without further analysis. Further analysis may give a more realistic situation of the internal forces for instance in case of uniformly buildingup of normal force in the compression crosssection part.
 The design compression resistance of a crosssection for uniform compression should be assumed to act at the centroid of its effective crosssection. If this does not coincide with the centroid of its gross crosssection, the shift e_{N} of the centroidal axes (see Figure 6.1) should be taken into account, using the method given in 31 6.1.9. If the shift of the neutral axis gives a favourable result, then that shift should be neglected only if the shift has been calculated at yield strength and not with the actual compressive stresses.
Figure 6.1 – Illustration of shift of neutral axis in crosssection under compression
6.1.4 Bending moment
6.1.4.1 Elastic and elasticplastic resistance with yielding at the compressed flange
 The design moment resistance of a crosssection for bending M_{c,Rd} should be determined as follows:
  if the effective section modulus W_{eff} is less than the gross elastic section modulus W_{el}:
M_{c,Rd} = W_{eff} f_{o} / γ_{M1} (6.4)
  if the effective section modulus W_{eff} is equal to the gross elastic section modulus W_{el}:
M_{c,Rd} = f_{o}(W_{el} + (W_{pl} – W_{el}) 4(1 – λ / λ_{el}))/ γ_{M1} but not more than W_{pl} f_{o} / γ_{M1} (6.5)
where:
λ is the slenderness of the crosssection part which correspond to the largest value of λ / λ_{el} ;
For double supported plane crosssection parts and where is found in Table 5.2; For stiffened crosssection parts and λ_{el} = 0,25, see 5.5.3.1.
NOTE The resulting bending moment resistance as a function of the slenderness of the most slender crosssection part is illustrated in Figure 6.2.
Figure 6.2  Bending moment resistance as a function of the slenderness
 Expression (6.5) is applicable provided that the slope ϕ of the web relative to the flanges (see Figure 6.5) is less than 60°.
 If (2) is not fulfilled the following expression should be used:
32
M_{c,Rd} = W_{el} f_{o} / γ_{M1} (6.6)
 The effective section modulus W_{eff} should be based on an effective crosssection that is subject only to bending moment, with a maximum stress σ_{max,Ed} equal to f_{o} / γ_{M1}, allowing for the effects of local and distortional buckling as specified in 5.5. Where shear lag is relevant (see EN 199911), allowance should also be made for its effects.
 The stress ratio ψ = σ_{2} / σ_{1} used to determine the effective portions of the web may be obtained by using the effective area of the compression flange but the gross area of the web, see Figure 6.3.
 If yielding occurs first at the compression edge of the crosssection, unless the conditions given in 6.1.4.2 are met the value of W_{eff} should be based on a linear distribution of stress across the crosssection.
Figure 6.3  Effective crosssection for resistance to bending moments
 If redistribution of bending moments is assumed in the global analysis the provisions given in 7.2 should be satisfied. If the residual moment at the intermediate support is not assumed to be zero, the acting residual moment should be determined by test.
6.1.4.2 Elastic and elasticplastic resistance with yielding at the tension flange only
 Provided that yielding occurs first at the tension edge, plastic reserves in the tension zone may be utilised without any strain limitation until the maximum compressive stress σ_{com,Ed} reaches f_{o}/γ_{M1}. In this clause only the bending case is considered. For axial load and bending 6.1.8 or 6.1.9 should be applied.
 In this case, the effective partially plastic section modulus W_{pp,eff} should be based on a stress distribution that is bilinear in the tension zone but linear in the compression zone.
 In the absence of a more detailed analysis, the effective thickness t_{eff} of the webs may be obtained using 5.5.2 by basing e_{c} on the bilinear stress distribution (see Figure 6.4), by assuming ψ = – 1.
Figure 6.4  Measure e_{c} for determination of effective thickness
 If redistribution of bending moments is assumed in the global analysis the provisions given in 7.2 should be satisfied. If the residual moment at the intermediate support is not assumed to be zero, the acting residual moment should be determined by test.
6.1.4.3 Effects of shear lag
 The effects of shear lag should be taken into account according to EN 199911.
33
 Shear lag effects may be ignored for flanges with b/t ≤ 300.
6.1.5 Shear force
 The shear resistance V_{b,Rd} should be determined from:
V_{b,Rd} = (h_{w} / sin ϕ) t f_{bv} / γ_{M1} (6.7)
where:
f_{bv} 
is the shear strength considering buckling according to Table 6.1; 
h_{w} 
is the web height between the midlines of the flanges, see Figure 6.5; 
ϕ 
is the slope of the web relative to the flanges. 
Table 6.1  Shear buckling strength f_{bv} in relation to web slenderness parameter
Web slenderness parameter 
Web without stiffening at the support 
Web with stiffening at the support ^{1)} 

0,58 f_{o} 
0,58 f_{o} 






1) Stiffening at the support, such as cleats, arranged to prevent distortion of the web and designed to resist the support reaction. 
 The web slenderness parameter should be obtained from the following:
  for webs without longitudinal stiffeners:
  for webs with longitudinal stiffeners, see Figure 6.5:
with:
where:
I_{s} 
is the second moment of area of the individual longitudinal stiffener, about the axis a  a as indicated in Figure 6.5; 
s_{d} 
is the total developed slant height of the web, as indicated in Figure 6.5; 
s_{p} 
is the slant height of the largest plane part in the web, see Figure 6.5; 
s_{w} 
is the slant height of the web, as shown in Figure 6.5, between the midpoints of the comers, see Figure 6.5. 
34
Figure 6.5  Geometry of a longitudinally stiffened web and effective cross section of stiffener
6.1.6 Torsion
 Torsion stiffness and resistance is negligible in profiled sheeting.
6.1.7 Local transverse forces
6.1.7.1 General
 To avoid crushing, crippling or buckling in a web subject to a support reaction or other local transverse force applied through the flange, the transverse force F_{Ed} should satisfy:
F_{Ed} ≤ R_{w,Rd} (6.10)
where R_{w,Rd} is the local transverse resistance of the web.
 The local transverse resistance of a web R_{w,Rd} should be obtained as follows:
 for unstiffened webs: from 6.1.7.2
 for stiffened webs: from 6.1.7.3
 Where the local load or support reaction is applied through a cleat that is arranged to prevent distortion of the web and is designed to resist the local transverse force, the local resistance of the web to the transverse force need not be considered.
6.1.7.2 Crosssections with unstiffened webs
 The local transverse resistance of an unstiffened web, see Figure 6.6, should be determined as specified in (2), provided that both of the following conditions are satisfied:
  the clear distance c from the actual bearing point for the support reaction or local load to a free end, see Figure 6.7, is at least 40 mm;
  the crosssection satisfies the following criteria:
r/t ≤ 10 (6.11a)
h_{w}/t ≤ 200 sin ϕ (6.11b)
45 ≤ ϕ ≤ 90° (6.11c)
35
where:
h_{w} 
is the web height between the midlines of the flanges; 
r 
is the internal radius of the corners; 
ϕ 
is the slope of the web relative to the flanges [degrees]. 
Figure 6.6  Examples of crosssection with two or more webs
 Where both conditions specified in (1) are satisfied, the local transverse resistance R_{w,Rd} per web of the sheeting profile should be determined from:
where:
l_{a} 
is the effective bearing length for the relevant category, see (4); 
α 
is the coefficient for the relevant category, see (3); 
s_{w} 
is the slant length of the web (= h_{w} / sinϕ); 
r 
is the inner bending radius (r < 10 t). 
 The value of the coefficient α should be obtained from Figure 6.7.
 The values of l_{a} should be obtained from (5). The maximum design value for l_{a} is 200 mm. When the support is a coldformed section with one web or round tube, for s_{S} should be taken a value of 10 mm. The relevant category (1 or 2) should be based on the clear distance e between the local load and the nearest support, or the clear distance c from the support reaction or local load to a free end, see Figure 6.7.
 The value of the effective bearing length l_{a} for sheeting profiles should be obtained from the following:
 for Category 1:
l_{a} = s_{s} but l_{a} ≤ 40 mm (6.13a)
 for Category 2:
if β_{v} ≤ 0,2: l_{a} = s_{s} (6.13b)
if β_{v} ≥ 0,3: l_{a} = 10mm (6.13c)
if 0,2 < β_{v} < 0,3: interpolate linearly between the values of l_{a} for 0,2 and 0,3 with:
in which V_{Ed,l} and V_{Ed,2} are the absolute values of the transverse shear force on each side of the local load or support reaction, and V_{Ed,l} ≥ V_{Ed,2} and s_{s} is the actual length of stiff bearing.
36
Figure 6.7  Local loads and supportcategories for crosssections with two or more webs
37
6.1.7.3 Stiffened webs
 The local transverse resistance of a stiffened web may be determined as specified in (2) for crosssections with longitudinal web stiffeners folded in such a way that the two folds in the web are on opposite sides of the system line of the web joining the points of intersection of the midline of the web with the midlines of the flanges, see Figure 6.8, that satisfy the condition:
2 < e_{max}/ t < 12 (6.15)
where:
e_{max} is the larger eccentricity of the folds relative to the system line of the web.
 For crosssections with stiffened webs satisfying the conditions specified in (1), the local transverse resistance of a stiffened web may be determined by multiplying the corresponding value for a similar unstiffened web, obtained from 6.1.7.2, by the factor κ_{a,s} given by:
κ_{a,s} = 1,45 – 0,05 e_{max}/ t but κ_{a,s} ≤ 0,95 + 35 000 t^{2} e_{min}/(b_{d}^{2} s_{p}) (6.16)
where:
b_{d} 
is the developed width of the loaded flange, see Figure 6.8; 
e_{min} 
is the smaller eccentricity of the folds relative to the system line of the web, see Figure 6.8; 
s_{p} 
is the slant height of the plane web crosssection part nearest to the loaded flange, see Figure 6.8. 
Figure 6.8  Support loads and geometry of stiffened webs
6.1.8 Combined tension and bending
 Crosssections subject to combined axial tension N_{Ed} and bending moment M_{y,Ed} should satisfy the criterion:
38
where:
N_{t,Rd} 
is the design resistance of a crosssection for uniform tension (6.1.2); 
M_{cy,Rd,ten} 
is the design moment resistance of a crosssection for maximum tensile stress if subject only to moment about the y  y axes (6.14). 
 If M_{cy,Rd,com} ≤ M_{cy,Rd,ten}, where M_{cy,Rd,com} is the moment resistance for the maximum compressive stress in a crosssection that is subject to moment only, the following criterion should also be satisfied:
6.1.9 Combined compression and bending
 Crosssections subject to combined axial compression N_{Ed} and bending moment M_{y,Ed} should satisfy the criterion:
in which N_{c,Rd} is as defined in 6.1.3 and M_{cy,Rd,com} is as defined in 6.1.8.
 The additional moment ΔM_{y,Ed} due to shift of the centroidal axis should be taken as:
ΔM_{y,Ed} = N_{Ed} e_{N} (6.18b)
in which e_{N} is the shift of the y  y centroidal axes due to axial forces, see 6.1.3(3).
 If M_{cy,Rd,ten} ≤ M_{cy,Rd,com} the following criterion should also be satisfied:
in which M_{cy,Rd,ten} is as defined in 6.1.8.
6.1.10 Combined shear force, axial force and bending moment
 Provided that V_{Ed}/V_{w,Rd} (see below) does not exceed 0,5, the design resistance to bending moment and axial force need not be reduced to allow for the shear force. If V_{Ed}/V_{w,Rd} is more than 0,5 the combined effects of an axial force N_{Ed}, a bending moment M_{Ed} and a shear force V_{Ed} should satisfy:
where:
N_{Rd} 
is the design resistance of the crosssection for tension or compression given in 6.1.2 or 6.1.3; 
M_{y,Rd} 
is the design moment resistance of the crosssection given in 6.1.4; 39 
V_{w,Rd} 
is the design shear resistance of the web given in 6.1.5. For members with more than one web V_{w,Rd} is the sum of the resistances of the webs; 
M_{f,Rd} 
is the design plastic moment resistance of the crosssection consisting of the effective area of the flanges only; 
M_{pl,Rd} 
is the design plastic moment resistance of the crosssection consisting of the effective area of the flanges and the fully effective web irrespective of its section class. 
6.1.11 Combined bending moment and local load or support reaction
 Crosssections subject to the combined action of a bending moment M_{Ed} and a transverse force due to a local load or support reaction F_{Ed} should satisfy the following:
where:
M_{c,Rd} 
is the moment resistance of the crosssection given in 6.1.4.1; 
R_{w,Rd} 
is the appropriate value of the sum of the local transverse resistances of the individual webs from 6.1.7. 
 In expression (6.22) the bending moment M_{Ed} may be calculated at the edge of the support.
6.2 Buckling resistance
6.2.1 General
 The effects of local and distortional buckling should be taken into account. Methods as specified in 5.5 may be used.
 The internal axial force in a sheeting should be taken as acting at the centroid of its gross crosssection.
 The resistance of sheeting to axial compression should be assumed to act at the centroid of its effective crosssection. If this does not coincide with the centroid of its gross crosssection, moments corresponding to the shift of the centroidal axes (see Figure 6.9) should be taken into account, using the method given in 6.2.3.
Figure 6.9 – Illustration of shift of centroidal axis of effective crosssection
40
6.2.2 Axial compression
6.2.2.1 Design flexural buckling resistance
 The design buckling resistance for axial compression N_{b,Rd} should be obtained from:
N_{b,Rd} = χA_{eff}f_{o} / γ_{M1} (6.23)
where:
A_{eff} 
is the effective area of the crosssection, obtained from Section 5 by assuming a uniform compressive stress σ_{com,Ed} equal to f_{o}/γ_{M1}; 
χ 
is the appropriate value of the reduction factor for bucklilng resistance. 
 The reduction factor χ for buckling resistance should be determined from:
with:
where:
α 
is an imperfection factor; 

is the limit of the horizontal plateau; 
λ 
is the slenderness parameter for the relevant buckling mode. 
 The imperfection factor for sheeting is α = 0,13 and the limit of the horizontal plateau is .
 The slenderness parameter for flexural buckling should be determined from the following:
where:
l 
is the buckling length for flexural buckling about the y – y axes (l_{y}); 
i 
is the radius of gyration about the corresponding axes (i_{y}), based on the properties of the gross crosssection. 
6.2.3 Bending and axial compression
 All members subject to combined bending and axial compression should satisfy the criterion:
where:
A_{eff} 
is the effective area of an effective crosssection that is subject only to axial compression; see Figure 6.10(a); 
W_{eff,y,com} 
is the effective section modulus for the maximum compressive stress in an effective crosssection that is subject only to moment about the y  y axis, see Figure 6.10 (b); 41 
ΔM_{y,Ed} 
is the additional moment due to possible shift of the centroidal axis in the y direction, see 6.1.9(2); 
χ_{y} 
is the reduction factor from 6.2.2 for buckling about the y  y axis; 
ω_{x} 
is an interaction expression, see (2). 
Figure 6.10 – Models for calculation of effective section properties
 For sheeting subjected to combined axial force and unequal end moments and/or transverse loads, different sections along the span should be checked. The actual bending moment in the studied section is used in the interaction expression and
where:
x_{s} 
is the distance from the studied section to a hinged support or a point of contraflexure of the deflection curve for elastic buckling of an axial force only, see Figure 5.9 of EN199911. 
l_{c} = KL 
is the buckling length, see Table 5.7 of EN199911. 
NOTE For simplification ω_{x} = 1 may be used.
6.3 Stressed skin design
6.3.1 General
 The interaction between structural members and sheeting panels that are designed to act together as parts of a combined structural system, may be allowed for as described in this chapter 6.3
 Diaphragms may be formed from profiled sheeting of aluminium used as roof or wall cladding.
NOTE Information on the verification of such diaphragms can be obtained from:
ECCS Publication No. 88 (1995): European recommendations for the application of metal sheeting acting as a diaphragm.
6.3.2 Diaphragm action
 In stressed skin design, advantage may be taken of the contribution that diaphragms of sheeting used as roofing, flooring or wall cladding make to the overall stiffness and strength of the structural frame, by means of their stiffness and strength in shear.
 Roofs and floors may be treated as deep plate girders extending throughout the length of a building, resisting transverse inplane loads and transmitting them to end gables, or to intermediate stiffened frames. The panel of sheeting may be treated as a web that resists inplane transverse loads in shear, with the edge members acting as flanges that resist axial tension and compression forces, see Figures 6.11 and 6.12.
42
 Similarly, rectangular wall panels may be treated as bracing systems that act as shear diaphragms to resist inplane forces.
Figure 6.11  Stressed skin action in a flatroof building
6.3.3 Necessary conditions
 Methods of stressed skin design that utilize sheeting as an integral part of a structure, may be used only under the following conditions:
  the use made of the sheeting, in addition to its primary purpose, is limited to the formation of shear diaphragms to resist structural displacement in the plane of that sheeting;
  the diaphragms have longitudinal edge members to carry flange forces arising from diaphragm action;
  the diaphragm forces in the plane of a roof or floor are transmitted to the foundations by means of braced frames, further stressedskin diaphragms, or other methods of sway resistance;
  suitable structural joints are used to transmit diaphragm forces to the main framework and to join the edge members acting as flanges;
  the sheeting is treated as a structural component that cannot be removed without proper consideration;
  the execution specification, including the calculations and drawings, draws attention to the fact that the building is designed to utilize stressed skin action;
  it is recommended to install warning signs to inform that the walls are utilized as structural skin components and any removal needs precaution to maintain stability.
 Stressed skin design should be used predominantly in lowrise buildings, or in the floors and facades of highrise buildings.
 Stressed skin diaphragms should be used predominantly to resist wind loads, snow loads and other loads that are applied through the sheeting itself. They may also be used to resist small transient loads, such as surge from light overhead cranes or hoists on runway beams, but may not be used to resist permanent external loads, such as those from plant.
43
Figure 6.12  Stressed skin action in a pitched roof building
6.3.4 Profiled aluminium sheet diaphragms
 In a profiled aluminium sheet diaphragm, see Figure 6.13, both ends of the sheets should be attached to the supporting members by means of selftapping screws, selfdrilling screws, welding, bolts or other fasteners of a type that will not work loose in service, pull out, or fail in shear before causing tearing of the sheeting. All such fasteners should be fixed directly through the sheeting into the supporting member, for example through the troughs of profiled sheets, unless special measures are taken to ensure that the joints effectively transmit the forces assumed in the design.
 The seams between adjacent sheets should be fastened by rivets, selfdrilling screws, welds, or other fasteners of a type that will not work loose in service, pull out, or fail in shear before causing tearing of the sheeting. The spacing of such fasteners should not exceed 500 mm.
 The distances from all fasteners to the edges and ends of the sheets should be adequate to prevent premature tearing of the sheets.
 Small randomly arranged openings, up to 3% of the relevant area, may be introduced without special calculation, provided that the total number of fasteners is not reduced. Openings up to 15% of the relevant area may be introduced if justified by detailed calculations. Areas that contain larger openings should be split into smaller areas, each with full diaphragm action.
 All sheeting that also forms part of a stressedskin diaphragm should first be designed for its primary purpose in bending. To ensure that any deterioration of the sheeting would be apparent in bending before the resistance to stressed skin action is affected, it should then be verified that the shear stress due to diaphragm action does not exceed 0,25f_{o}/γ_{M1}
 The shear resistance of a stressedskin diaphragm should be based on the least tearing strength of the seam fasteners or the sheettomember fasteners parallel to the corrugations or, for diaphragms fastened only to longitudinal edge members, the end sheettomember fasteners. The calculated shear resistance for any other type of failure should exceed this minimum value by at least the following:
  for failure of the sheettopurlin fasteners under combined shear and wind uplift, by at least 40%;
  for any other type of failure, by at least 25%.
44
Figure 6.13  Arrangement of an individual panel
6.4 Perforated sheeting with the holes arranged in the shape of equilateral triangles
 Perforated sheeting may be designed by calculation, provided that the rules for nonperforated sheeting are modified by introducing the effective thicknesses given below.
NOTE These calculation rules tend to give conservative values. More economical solutions might be obtained from design assisted by testing.
 Provided that 0,2 ≤ d/a ≤ 0,9 gross section properties may be calculated using 6.1.2 to 6.1.5, but replacing t by t_{a,eff} obtained from:
t_{a,eff} = 1,18t(1 – d/(0,9a)) (6.28)
where:
d 
is the diameter of the perforations; 
a 
is the spacing between the centres of the perforations. 
 Provided that 0,2 ≤ d/a ≤ 0,9 effective section properties may be calculated using 5.5, but replacing t by t_{b,eff} obtained from:
 Provided that 0,2 ≤ d/a ≤ 0,8 the resistance of a single unstiffened web to local transverse forces may be calculated using 6.1.7, but replacing t by t_{c,eff} obtained from:
where:
s_{per} 
is the slant height of the perforated portion of the web, centric in the web height; 
s_{w} 
is the total slant height of the web. 
45
7 Serviceability limit states
7.1 General
 The rules for serviceability limit states given in EN 199911 should also be applied to coldformed sheeting.
 The properties of the effective crosssection for serviceability limit states obtained from (3) should be used in all serviceability limit state calculations for coldformed sheeting.
 The second moment of area may be calculated by interpolation of gross crosssection and effective crosssection using the expression:
I_{eff,ser} = I_{gr}  σ_{gr}(I_{gr}  I_{eff}) / f_{o} (7.1)
where:
I_{gr} 
is the second moment of area of gross section; 
I_{eff} 
is the second moment of area of the effective crosssection in the ultimate limit state, with allowance for local buckling; 
σ_{gr} 
is the maximum compressive bending stress in the serviceability limit state, based on the gross crosssection (positive in the formula). 
 The effective second moment of area I_{eff,ser} may be taken as variable along the span. Alternatively a uniform value may be used, based on the maximum span moment due to serviceability loading.
7.2 Plastic deformation
 In case of plastic global analysis, the combination of support moment and support reaction at an internal support should not exceed 0,9 times the combined design resistance determined using γ_{M,ser} and I_{eff,ser} according to 7.1(3).
 The combined design resistance may be determined from expression (6.22) in 6.1.11, but using the effective crosssection for serviceability limit states and γ_{M,ser} .
7.3 Deflections
 The deflections may be calculated assuming elastic behaviour.
 The influence of slip in the joints (for example in the case of continuous sheeting with overlaps) should be considered in the calculation of deflections, forces and moments.
NOTE For commonly used fasteners according to 8.2 and 8.3 the slip may be ignored.
 With reference to EN 1990 – Annex A1.4 limits for deflections should be specified for each project and agreed with the client.
NOTE The National Annex may specify the limits.
46
8 Joints with mechanical fasteners
8.1 General
 Joints with mechanical fasteners should be compact in shape. The positions of the fasteners should be arranged to provide sufficient room for satisfactory assembly and maintenance.
 The shear forces on individual mechanical fasteners in a joints may be assumed to be equal, provided that:
  the fasteners have sufficient ductility;
  shear of the fastener is not the critical failure mode.
 For design by calculation, the resistance of mechanical fasteners subject to predominantly static loads should be determined from 8.2 for blind rivets and 8.3 for selftapping screws and selfdrilling screws.
 The meanings of the symbols, used in the above named clauses are found in EN 199911 with additions in 1.4 of EN 199914.
 The partial factor for calculating the design resistances of mechanical fasteners should be taken as γ_{M3} according to 2(3).
Figure 8.1  End distance, edge distance and spacing for fasteners
 The pullthrough resistances given in 8.2.3.1 for blind rivets or in 8.3.3.1 for selftapping screws and selfdrilling screws are depending on the location of the fasteners and should be reduced if the fasteners are not located centrally in the troughs of the sheeting. If attachment is at a quarter point, the design resistance should be reduced to 0,9F_{p,Rd} and if there are fasteners at both quarter points, the resistance should be taken as 0,7F_{p,Rd} per fastener, see Table 8.3.
 For a fastener loaded in combined shear and tension, provided that F_{p,Rd}, F_{o,Rd}, F_{b,Rd} and F_{n,Rd} are determined by calculation on the basis of 8.2 for blind rivets or 8.3 for selftapping screws and selfdrilling screws, the resistance of the fastener to combined shear and tension may be verified using:
 The gross section distortion may be neglected if the design resistance is obtained from 8.2.3 and 8.3.3 provided that the fastening is through a flange not more than 150 mm wide.
 The diameter of holes for screws should be in accordance with the manufacturer’s guidelines. These guidelines should be based on following criteria:
47
  the applied torque should be just higher than the threading torque;
  the applied torque should be lower than the thread stripping torque or headshearing torque;
  the threading torque should be smaller than 2/3 of the headshearing torque.
 The design rules for blind rivets are valid only if the diameter of the hole is not more than 0,1 mm larger than the diameter if the rivet.
8.2 Blind rivets
8.2.1 General
 The resistance of blind rivets loaded in shear is the minor value of the bearing resistance F_{b,Rd}, the netsection resistance F_{net,Rd} of the sheeting and the shear resistance of the fastener F_{v,Rd}.
 The shank of the blind rivet should be of EN AW 5019.
 Blind rivets according to EN ISO 15973, EN ISO 15974, EN ISO 15977, EN ISO 15978, EN ISO 15981 or EN ISO 15982 should be used
8.2.2 Design resistances of riveted joints loaded in shear
8.2.2.1 Bearing resistance
F_{b,Rd} = 1,5 f_{u,min} t d / γ_{M3} for t_{sup} / t ≥ 2,5 (8.2b)
For thicknesses 1,0 < t_{sup} / t < 2,5 the bearing resistance F_{b,Rd} may be obtained by linear interpolation.
8.2.2.2 Net section resistance
F_{net,Rd} = A_{net} f_{u} / γ_{M3} (8.3)
8.2.2.3 Shear resistance
F_{v,Rd} = 38 d^{2} / γ_{M3} [N] with d in mm (8.4)
Conditions for bearing and shear resistance:
  f_{u,min} > 260 N/mm^{2} should not be taken into account
  2,6 mm ≤ d ≤ 6,4 mm
8.2.3 Design resistances for riveted joints loaded in tension
8.2.3.1 Pullthrough resistance
F_{p,Rd} = 2,35 α_{E} t f_{o} / γ_{M3} [N] with t in mm and f_{o} in N/mm^{2} ; α_{E} according to Table 8.3 (8.5)
Conditions:
  t ≤ 1,5 mm; d_{w} ≥ 9,5 mm;
  f_{o} > 220 N/mm^{2} should not be taken into account
8.2.3.2 Pullout resistance
  Supporting member of steel: F_{o,Rd} = 0,47 t_{sup} d f_{y} / γ_{M3} (8.6)
48
  Supporting member of aluminium: F_{o,Rd} = 0,20 t_{sup} d f_{o} / γ_{M3} (8.7)
Conditions:
  t_{sup} > 6 mm, f_{y}> 350 N/mm^{2}, f_{o} > 220 N/mm^{2} should not be taken into account (everyone to be fulfilled)
  the drilling holes have to be performed according to the recommendations of the manufacturer
8.2.3.3 Tension resistance
F_{t,Rd} = 47 d^{2} /γ_{M3} [N], where d to be taken in mm. (8.8)
8.3 Selftapping / selfdrilling screws
8.3.1 General
 The resistance of screws loaded in shear is the minor value of the bearing resistance F_{b,Rd}, the netsection resistance F_{net,Rd} of the sheeting and the shear resistance of the fastener F_{v,Rd}.
 The limits for diameters of screws given in the following clauses should be valid, unless other limits can be obtained and verified by adequate tests.
 The limits for strength values of supporting materials should be valid, unless other limits can be obtained and verified by adequate tests.
 Selftapping screws according to EN ISO 1479, EN ISO 1481 or ISO 7049 should be used.
 Selfdrilling screws according to EN ISO 15480 or EN ISO 15481 should be used.
8.3.2 Design resistance of screwed joints loaded in shear
8.3.2.1 Bearing resistance
 Bearing resistance if supporting members are of steel or aluminium is given by:
F_{b,Rd} = 1,5 f_{u,min} t d / γ_{M3} for t_{sup} / t ≥ 2,5 (8.9b)
For thicknesses 1,0 < t_{sup} / t < 2,5 the bearing resistance F_{b,Rd} may be obtained by linear interpolation.
Conditions:
  self tapping and self drilling screws should be of steel or stainless steel with diameter d ≥ 5,5 mm,
  f_{u,min} > 260 N/mm^{2} should not be taken into account;
  for t > t_{sup} take t = t_{sup};
  the drilling holes have to be performed according to the recommendations of the manufacturer.
 Bearing resistance of aluminium sheeting if supporting members are of timber is given by:
F_{b,Rd} ≤ l,5 t d f_{u,min} / γ_{M3} [N] (8.10)
 For resistance of supporting member of timber, see EN 199511, Section 8, steeltotimber connection.
Conditions:
  selftapping and self drilling screws of steel or stainless steel with 5,5 mm ≤ d ≤ 8 mm;
  edge distances and spacing in the member of timber, see EN 199511, Section 8.
49
8.3.2.2 Net section resistance
F_{net,Rd} = A_{net} f_{u} / γ_{M3} (8.11)
8.3.2.3 Shear resistance
Design shear resistance of screws of steel or stainless steel is given by:
F_{v,Rd} = 380 A_{s} / γ_{M3} [N], with A_{s} in mm^{2} (8.12)
8.3.3 Design resistance of screwed joints loaded in tension
8.3.3.1 Pullthrough resistance
 The pullthrough resistance of screwed joints loaded in tension is given by:
with: t and d_{w} in mm and f_{u} in N/ mm^{2} and
  α_{L} correction factor with respect to tension in bending (Table 8.1);
  α_{M} correction factor with respect to the type of washer (Table 8.2);
  α_{E} correction factor with respect to the location of fasteners (Table 8.3).
Conditions:
  t ≤ 1,5 mm;
  d_{w} ≥ 14 mm and thickness of the washer ≥ 1 mm;
  width of the adjacent flange of the sheet crosssection part ≤ 200 mm;
  d_{w} > 30 mm and f_{u} > 260 N/mm should not be taken into account;
  at a depth of the sheeting smaller than 25 mm, the pullthrough resistance should be reduced by 30 %.
Table 8.1  Correction factor α_{L}, to take account of tensile bending stresses at support fastenings
Ultimate strength [N/mm^{2}] 
α_{L} 
Span L < 1,5 m 
Span l,5 ≤ L ≤ 4,5 m 
Span L > 4,5 m 
< 215 
1 
1 
1 
≥ 215 
1 
1,25 L/6 
0,5 
NOTE At end supports without bending stresses and at connections at the upper flange always α_{L} = 1
Table 8.2  Correction factor α_{M} to take account of the material of the washer
Material of the washer 
α_{M} 
Carbon steel, stainless steel 
1,0 
Aluminium 
0,8 
50
Table 8.3  Correction factor α_{E} to take account of the location of the fasteners
For the flange in contact with the support 
without contact 
Joint 







α_{E} 
1,0 
b_{u} ≤ 150:0,9 b_{u} ≤ 150:0,7 
0,7 
0,9 
0,7 0,7 
1,0 
0,9 
NOTE The combination of correction factors is not necessary. The smallest value applies.
8.3.3.2 Pullout resistance
 The pullout resistance for self tapping screws and selfdrilling screws of steel or stainless steel, where supporting members are of steel or aluminium, is given by:
Conditions:
  selftapping screws and selfdrilling screws of steel or stainless steel;
  diameter of the screws 6,25 mm ≤ d ≤ 6,5 mm;
  t_{sup} > 6 mm and f_{u,sup} > 250 N/ mm^{2} for aluminium or
  t_{sup} > 5 mm and f_{u,sup} > 400 N/ mm^{2} for steel should not be taken into account;
  the diameter of the drilling hole should be in accordance with the recommendations of the manufacturer.
 For supporting members of timber, see EN 199511, Section 8.
8.3.3.3 Tension resistance
 The design tension resistance of screws of steel or stainless steel is given by:
F_{t,Rd} = 560 A_{s} / γ_{M3} [N] with A_{S} in mm^{2} (8.15)
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9 Design assisted by testing
 This Section 9 may be used to apply the principles for design assisted by testing given in EN 1990 with the additional specific requirements of coldformed sheeting.
 Testing of profile sheeting should apply the principles given in Annex A.
 Tensile testing of aluminium alloys should be carried out in accordance with EN 100021. Testing of other aluminium properties should be carried out in accordance with the relevant European Standards.
 Testing of fasteners and connections should be carried out in accordance with the relevant European Standard or International Standard.
NOTE Pending availability of an appropriate European or International Standard, information on testing procedures for fasteners can be obtained from:
ECCS Publication No. 21 (1983): European recommendations for steel construction: the design and testing of connections in steel sheeting and sections;
ECCS Publication No. 42 (1983): European recommendations for steel construction: mechanical fasteners for use in steel sheeting and sections.
52
Annex A – Testing procedures
[normative]
A.1 General
 This Annex A gives appropriate standardized testing and evaluation procedures for a number of tests that are commonly required in practice, as a basis for harmonization of future testing.
NOTE 1 In the field of coldformed sheeting, many standard products are commonly used for which design by calculation might not lead to economical solutions, so it is frequently desirable to use design assisted by testing.
NOTE 2 The National Annex may give further information on testing and on the evaluation of test results
NOTE 3 The National Annex may give conversion factors for existing test results to be equivalent to the outcome of standardised tests according to this annex.
 This annex covers:
  tests on profiled sheets, see A.2;
  valuation of test results to determine design values, see A.3.
A.2 Tests on profiled sheets
A.2.1 General
 Loading may be applied through air bags or in a vacuum chamber or by metal or timber cross beams arranged to simulate uniformly distributed loading.
 To prevent spreading of corrugations, transverse ties or other appropriate test accessories such as timber blocks may be applied to the test specimen. Some examples are given in Figure A.1.
 Test specimens for sheet profiles should normally comprise at least two complete corrugations, but a test specimen may comprise just one complete corrugation, provided that the stiffness of the corrugations is sufficient. Free longitudinal edges should be in the tension zone during test procedure.
Figure A.1  Examples of appropriate test accessories
 For uplift tests, the test setup should realistically simulate the behaviour of the sheeting under practical conditions. The type of joints between the sheet and the supports should be the same as in the joints to be used in practice.
 To give the results a wide range of applicability, hinged and roller supports should preferably be used, to avoid any influence of torsional or longitudinal restraint at the supports on the test results. 53
 It should be ensured that the direction of the loading remains perpendicular to the initial plane of the sheet throughout the test procedure.
 To eliminate the deformations of the supports, the deflections at both ends of the test specimen should also be measured.
 The test result should be taken as the maximum value of the loading applied to the specimen either coincident with failure or immediately prior to failure as appropriate.
A.2.2 Single span test
 A test setup equivalent to that shown in Figure A.2 may be used to determine the midspan moment resistance (in the absence of shear force) and the effective flexural stiffness.
 The span should be chosen such that the test results represent the moment resistance of the sheet.
 The moment resistance should be determined from the test result.
 The flexural stiffness should be determined from a plot of the loaddeflection behaviour.
A.2.3 Double span test
 The test setup shown in Figure A.3 may be used to determine the resistance of a sheet that is continuous over two or more spans to combinations of moment and shear at internal supports, and its resistance to combined moment and support reaction for a given support width.
 The loading should preferably be uniformly distributed (applied using an air bag or a vacuum chamber, for example).
 Alternatively any number of line loads (transverse to the span) may be used, arranged to produce internal moments and forces that are appropriate to represent the effects of uniformly distributed loading. Some examples of suitable arrangements are shown in Figure A.4.
A.2.4 Internal support test
 As an alternative to A.2.3, the test setup shown in Figure A.5 may be used to determine the resistance of a sheet that is continuous over two or more spans to combinations of moment and shear at internal supports, and its resistance to combined moment and support reaction for a given support width.
 The test span s used to represent the portion of the sheet between the points of contraflexure each side of the internal support, in a sheet continuous over two equal spans L may be obtained from:
s = 0,4 L (A.1)
 If plastic redistribution of the support moment is expected, the test span s should be reduced to represent the appropriate ratio of support moment to shear force.
 The width b_{B} of the beam used to apply the test load should be selected to represent the actual support width to be used in practice.
 Each test result may be used to represent the resistance to combined bending moment and support reaction (or shear force) for a given span and a given support width. To obtain information about the interaction of bending moment and support reaction, tests should be carried out for several different spans.
54
Figure A.2  Test setup for single span tests
Figure A.3  Test setup for double span tests
Figure A.4  Examples of suitable arrangements of alternative line loads
55
Figure A.5  Test setup for internal support test
Figure A.6  Test setup for end support tests
A.2.5 End support test
 The test setup shown in Figure A.6 may be used to determine the resistance of a sheet at an end support.
 Separate tests should be carried out to determine the shear resistance of the sheet for different lengths u from the contact point at the inner edge of the end support, to the actual end of the sheet, see Figure A.6.
56
A.3 Evaluation of test results
A.3.1 General
 A specimen under test should be regarded as having failed if the applied test loads reach their maximum values, or if the gross deformations exceed specified limits.
 In the testing of joints, or of components in which the examination of large deformations is necessary for accurate assessment (for example, in evaluating the momentrotation characteristics of sleeves), no limit need be placed on the gross deformation during the test.
 An appropriate margin of safety should be available between a ductile failure mode and possible brittle failure modes. As brittle failure modes do not usually appear in largescale tests, additional detail tests should be carried out where necessary.
NOTE This is often the case for joints.
A.3.2 Adjustment of test results
 Test results should be appropriately adjusted to allow for variations between the actual measured properties of the test specimens and their nominal values.
 The actual measured 0,2 % proof strength f_{0,2,obs} should not deviate by more than ± 25% from the nominal 0,2 % proof strength f_{0,2}.
 The actual measured material thickness t_{obs} should not exceed the design thickness t based on the nominal material thickness t_{nom} by more than 12%.
 Adjustments should be made in respect of the actual measured values of the material thickness t_{obs} and the 0,2 % proof strength f_{0,2,obs} all tests, except where the design expression that uses the test results also uses the actual measured value of the thickness or 0,2 % proof strength of the material, as appropriate.
 The adjusted value R_{adj,i} of the test result for test i should be determined from the actual measured test result R_{obs,i} using:
R_{adj,i} = R_{obs,i} / μ_{R} (A.2)
in which μ_{R} is the resistance adjustment coefficient given by:
 The exponent α for use in expression (A.2) should be obtained as follows:
  if f_{0,2,obs} ≤ f_{0,2}: α = 0
  if f_{0,2,obs} ≤ f_{0,2} α = 1
  for profiled sheets in which compression parts have such large b_{p} / t ratios that local buckling is clearly the
failure mode: α = 0,5
 The exponent β for use in expression (A.2) should be obtained as follows:
  if t_{obs} ≤ t: β = l
  if t_{obs} > t: β = 2
57
A.3.3 Characteristic values
A.3.3.1 General
 Characteristic values may be determined statistically, provided that there are at least 4 test results.
NOTE A larger number is generally preferable, particularly if the scatter is relatively wide.
 The characteristic minimum value should be determined using the following provisions. If the characteristic maximum value or the characteristic mean value is required, it should be determined by using appropriate adaptations of the provisions given for the characteristic minimum value.
 The characteristic value of a resistance R_{k} determined on the basis of at least 4 tests may be obtained from:
R_{k} = R_{m} – k s (A.4)
where:
s 
is the standard deviation; 
k 
is the appropriate coefficient from Table A.1; 
R_{m} 
is the mean value of the adjusted test results R_{adj}. 
 The standard deviation s may be determined using:
where:
R_{adj,i} 
adjusted test result for test i; 
n 
is the number of tests. 
Table A.1  Values of the coefficient k
n 
4 
5 
6 
8 
10 
20 
30 
∞ 
k 
2,63 
2,33 
2,18 
2,00 
1,92 
1,76 
1,73 
1,64 
A.3.3.2 Characteristic values for families of tests
 A series of tests carried out on a number of otherwise similar sheets, in which one or more parameters is varied, may be treated as a single family of tests, provided that they all have the same failure mode. The parameters that are varied may include crosssectional dimensions, spans, thicknesses and material strengths.
 The characteristic resistances of the members of a family may be determined on the basis of a suitable design expression that relates the test results to all the relevant parameters. This design expression may either be based on the appropriate equations of structural mechanics, or determined on an empirical basis.
 The design expression should be modified to predict the mean measured resistance as accurately as practicable, by adjusting the coefficients to optimise the correlation.
NOTE Information on this process is given in Annex D of EN 1990.
 In order to calculate the standard deviation s, each test result should first be normalized by dividing it by the corresponding value predicted by the design expression. If the design expression has been modified as specified in (3), the mean value of the normalized test results will be unity. The number of tests n should be taken as equal to the total number of tests in the family. 58
 For a family of at least four tests, the characteristic resistance R_{k} should then be obtained from expression (A.3) by talking R_{m} as equal to the value predicted by the design expression, and using the value of k from Table A.1 corresponding to a value of n equal to the total number of tests in the family.
A.3.4 Design values
 The design value of a resistance R_{d} should be derived from the corresponding characteristic value R_{k} determined by testing, using:
R_{d} = R_{k} / (γ_{M} γ_{sys}) (A.6)
where:
γ_{M} 
is the partial factor for resistance; 
γ_{sys} 
is a partial factor for differences in behaviour under test conditions and service conditions. 
 For a family of at least four tests, the value of γ_{M} may be determined using statistical methods.
NOTE Information on an appropriate method is given in Annex D of EN 1990.
 Alternatively γ_{M} may be taken as equal to the appropriate value of γ_{M} for design by calculation given in Section 2.
NOTE The National Annex may give values for γ_{M} and γ_{sys}. A recommended value for γ_{sys} is 1,0 in case of sheeting.
 For other types of tests in which possible instability phenomena, or modes of behaviour, of structures or structural components might not be covered sufficiently by the tests, the value of γ_{sys} should be assessed taking into account the actual testing conditions, in order to achieve the necessary reliability.
A.3.5 Serviceability
 The provisions given in Section 7 should be satisfied.
59
Annex B – Durability of fasteners
[informative]
 For mechanical joints in coldformed sheeting Table B.1 may be applied
Table B.1  Fastener material with regard to corrosion environment (and sheeting material only for information). Only risk of corrosion is considered. Environmental corrosivity categories according to EN ISO 129442
Corrosivity category 
Sheet material 
Material of fastener 
Aluminium 
Electro galvanized steel. Coat thickness ≥ 7μm 
Hotdip zinc coated steel ^{b}. Coat thickness ≥ 45μm 
Stainless steel, case hardened. 1.4006 ^{d,e} 
Stainless steel, 1.4301 ^{d} 1.4436 ^{d} 
Monel ^{a} 
C1 
A, B, C D, E, S 
X X 
X X 
X X 
X X 
X X 
X X 
C2 
A C, D, E S 
X X X 
   
X X X 
X X X 
X X X 
X X X 
C3 
A C, E D S 
X X X  
    
X X X X 
 (X)^{c}  X 
X (X)^{c} (X)^{c} X 
X  X X 
C4 
A D E S 
X  X  
    
(X)^{c} X X X 
    
(X)^{c} (X)^{c} (X)^{c} X 
   X 
C5I 
A D^{f} S 
X   
   
 X  
   
(X)^{c} (X)^{c} X 
   
C5M 
A D^{f} S 
X   
   
 X  
   
(X)^{c} (X)^{c} X 
   
NOTE Fastener of steel without coating may be used in corrosivity category CI.
A = 
aluminium irrespective of surface finish 
B = 
uncoated steel sheet 
C = 
hotdip zinc coated (Z275) or aluzinc coated (AZ150) steel sheet 
D = 
hotdip zinc coated + coating of paint or plastic 
E = 
aluzinc coated (AZ185) steel sheet 
S = 
stainless steel 
X = 
type of material recommended from corrosion standpoint 
(X) = 
type of material recommended from corrosion standpoint under the specified condition only 
 = 
type of material not recommended from corrosion standpoint 
a 
refers to rivets only 
b 
refers to screws and nuts only 
c 
insulation washer of material resistant to aging between sheeting and fastener 
d 
stainless steel EN 10 088 
e 
risk of discoloration 
f 
always check with sheet supplier 
 The environmental corrosivity categories following EN ISO 129442 are presented in Table B.2.
60
Table B.2  Atmosphericcorroslvity categories according to EN ISO 129442 and example of typical environment
Corrosivity category 
Corrosivity level 
Example of typical environments in temperature climate (informative) 
Exterior 
Interior 
CI 
very low 
 
Heated buildings with clean atmospheres, e.g. offices, shops, schools, hotels. 
C2 
low 
Atmospheres with low level of pollution. Mostly rural areas. 
Unheated buildings where condensation may occur, e.g. depots, sport halls. 
C3 
medium 
Urban and industrial atmospheres, moderate sulphur dioxide pollution. Coastal areas with low salinity. 
Production rooms with high humidity and some air pollution, e.g. foodprocessing, plants, laundries, breweries and dairies. 
C4 
high 
Industrial areas and coastal areas with moderate salinity. 
Chemical plants, swimming pools, coastal ship and boatyards. 
C5I 
very high (industrial) 
Industrial areas with high humidity and aggressive atmospheres. 
Buildings and areas with almost permanent condensation and with high pollution. 
C5M 
very high (marine) 
Coastal and offshore areas with high salinity. 
Buildings and areas with almost permanent condensation and with high pollution 
61
Bibliography
 Weber, H.: Dach und Wand  Panen und Bauen mit AluminiumProfiltafeln; AluminiumVerlagDüsseldorf 1982 (in German)
 Richtlinie für die Verlegung von AluminiumProfiltafeln; AluminiumMerkblatt A7; Gesamtverband der Aluminiumindustrie, Düsseldorf 1995 (in German)
 Verbindungen Profiltafeln und dünnwandigen Bauteilen aus Aluminium; AluminiumMerkblatt A9; Gesamtverband der Aluminiumindustrie, Düsseldorf 1995 (in German)
 SFHFRichtlinien für hinterlüftete Fassaden  Grundsätze für Planung, Bemessung, Konstruktion und Ausführung; Schweizerischer Fachverband für hinterlüftete Fassaden; Zürich 1992 (in German and French)
 Directives APSFV pour façades ventilées; Principes et remarques pour l’étude, le dimensionnement, la construction et l’exécution; Association professionnelle suisse pour des façades ventilées (in French and German)
 AluminiumTrapezprofile und ihre Verbindungen  Kommentar zur Anwendung und Konstruktion. Gesamtverband der Aluminiumindustrie e.V. Am Bonneshof 5, D40 474 Düsseldorf.
 Baehre, R., Wolfram, R.: Zur Schubfeldberechnung von Trapezprofilen Stahlbau 6/1986, S. 175179
 Baehre, R., Huck, G.: Zur Berechnung der aufnehmbaren Normalkraft von Stahl Trapezprofilen nach DIN 18807 Teile 1 und 3, Stahlbau 69 (1990), Heft 8, S. 225  232
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