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CEN TC250 WG5
MASTER DOCUMENT
Participants of the Skype meeting of 08/02/2012: Roberto Canobbio, Giorgio Novati, Jean-Marc
Marion, Jean-Christophe Thomas, Peter Gosling, Guy Buyle, Marijke Mollaert, Bernd Stimpfle,
Natalie Stranghöner, Jörg Uhlemann, Seethaler Markus, Josep Llorenz, Rogier Houtman
Green: comments specified during the Skype meeting of 08/02/2012
Comments by Josep Llorens:
I propose to suppress "Foreword (Informative)", "Background of the Eurocode programme",
"Status and field of application of Eurocodes", "National Standards implementing Eurocodes" and
"Links between Eurocodes and harmonised technical specifications (ENs and ETAs) for products"
because they are repetitions.
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Contents
1
General ..................................................................................................................................... 6
1.1
Scope ................................................................................................................................. 6
1.2
Normative references ........................................................................................................ 7
1.3
Assumptions ...................................................................................................................... 7
1.4
Distinction between principles and application rules........................................................ 7
1.5
Terms and definitions........................................................................................................ 7
1.6
Symbols ............................................................................................................................. 9
2
Basis of design ....................................................................................................................... 10
2.1
Requirements .................................................................................................................. 10
2.2
Principles of limit state design ........................................................................................ 11
2.3
Basic variables ................................................................................................................ 11
2.4
Verification by the partial factor method ........................................................................ 13
2.5
Design assisted by testing ............................................................................................... 14
3
Materials ................................................................................................................................ 14
3.1
General ............................................................................................................................ 14
3.2
Coated Fabrics................................................................................................................. 14
3.3
Uncoated Fabrics............................................................................................................. 15
3.4
Films................................................................................................................................ 15
3.5
Connecting devices ......................................................................................................... 15
3.6
Structural Elements ......................................................................................................... 15
4
Durability ............................................................................................................................... 15
4.1
General ............................................................................................................................ 15
5
Basis of Structural analysis .................................................................................................... 16
5.1
General ............................................................................................................................ 16
5.2
Structural modelling for analysis .................................................................................... 16
5.3
Global analysis ................................................................................................................ 17
5.4
Imperfections .................................................................................................................. 17
5.5
Methods of analysis ........................................................................................................ 17
6
Ultimate limit states (ULS) .................................................................................................... 17
6.1
General ............................................................................................................................ 17
6.2
Resistance of material and joints .................................................................................... 18
6.3
Connections..................................................................................................................... 19
6.4
Design of ... subjected to ................................................................................................. 19
7
Serviceability limit states (SLS) ............................................................................................ 19
7.1
General ............................................................................................................................ 19
7.2
Serviceability limit states for buildings........................................................................... 19
7.3
Tear control ..................................................................................................................... 21
8
Details/Connections ............................................................................................................... 21
8.1
General ............................................................................................................................ 21
8.2
Membrane-membrane ..................................................................................................... 22
8.3
Membrane to others ........................................................................................................ 26
8.4
Reinforcements for edges, ridges, valleys, corners, high and low points ....................... 28
8.5
Stays, ties ........................................................................................................................ 29
8.6
Base plates for masts and anchors: moment resisting, singly or doubly hinged ............. 29
8.7
Anchors and foundations under tension .......................................................................... 29
9
Manufacture/Fabrication, handling & packing & Installation ............................................... 30
10 Inspection/Maintenance ......................................................................................................... 30
11 Design Assisted by Testing .................................................................................................... 30
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(cfr 5.2 in NBN-EN-1990) ............................................................................................................. 30
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[from EN 1990:2002 (E)]
Foreword (Informative)
This document (EN xxx:xxxx) has been prepared by Technical Committee CEN/TC 250
"Structural Eurocodes", the secretariat of which is held by BSI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by October 2002, and conflicting national standards
shall be withdrawn at the latest by March 2010.
This document supersedes ENV xxxx:xxxx.
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, Belgium,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, 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 1980’s.
In 1989, the Commission and the Member States of the EU and EFTA decided, on the basis of an
agreement1 between the Commission and CEN, to transfer the preparation and the publication of
the Eurocodes to CEN through a series of Mandates, in order to provide them with a future status
of European Standard (EN). This links de facto the Eurocodes with the provisions of all the
Council’s Directives and/or Commission’s Decisions dealing with European standards (e.g. the
Council Directive 89/106/EEC on construction products - Construction Products Directive 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:
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).
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EN 1990 Eurocode : Basis of Structural Design
EN 1991 Eurocode 1: Actions on structures
EN 1992 Eurocode 2: Design of concrete structures
EN 1993 Eurocode 3: Design of steel structures
EN 1994 Eurocode 4: Design of composite steel and concrete structures
EN 1995 Eurocode 5: Design of timber structures
EN 1996 Eurocode 6: Design of masonry structures
EN 1997 Eurocode 7: Geotechnical design
EN 1998 Eurocode 8: Design of structures for earthquake resistance
EN 1999 Eurocode 9: Design of aluminium structures
Eurocode standards recognise the responsibility of regulatory authorities in each Member State
and have safeguarded their right to determine values related to regulatory safety matters at
national level where these continue to vary from State to State.
Status and field of application of Eurocodes
The Member States of the EU and EFTA recognise that Eurocodes serve as reference documents
for the following purposes:
–
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 N°1 – Mechanical resistance and stability – and
Essential Requirement N°2 – Safety in case of fire;
–
as a basis for specifying contracts for construction works and related engineering services;
–
as a framework for drawing up harmonised technical specifications for construction
products (ENs and ETAs)
The Eurocodes, as far as they concern the construction works themselves, have a direct
relationship with the Interpretative Documents2 referred to in Article 12 of the CPD, although
they are of a different nature from harmonised product standards3.
Therefore, technical aspects arising from the Eurocodes work need to be adequately considered by
CEN Technical Committees and/or EOTA Working Groups working on product standards with a
view to achieving a full compatibility of these technical specifications with the Eurocodes.
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
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:
a) give concrete form to the essential requirements by harmonising the terminology and the technical bases and indicating classes or levels for each
requirement where necessary ;
b) indicate methods of correlating these classes or levels of requirement with the technical specifications, e.g. methods of calculation and of proof, technical
rules for project design, etc. ;
c) 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.
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The National Standards implementing Eurocodes will comprise the full text of the Eurocode
(including any annexes), as published by CEN, which may be preceded by a National title page
and National foreword, and may be followed by a National annex.
The National annex may only contain information on those parameters which are left open in the
Eurocode for national choice, known as Nationally Determined Parameters, to be used for the
design of buildings and civil engineering works to be constructed in the country concerned, i.e.:
– values and/or classes where alternatives are given in the Eurocode,
– values to be used where a symbol only is given in the Eurocode,
– country specific data (geographical, climatic, etc.), e.g. snow map,
– the procedure to be used where alternative procedures are given in the Eurocode.
It may also contain
– decisions on the application of informative annexes,
– references to non-contradictory complementary information to assist the user to apply the
Eurocode.
Links between Eurocodes and harmonised technical specifications (ENs and ETAs) for
products
There is a need for consistency between the harmonised technical specifications for construction
products and the technical rules for works4. Furthermore, all the information accompanying the
CE Marking of the construction products which refer to Eurocodes shall clearly mention which
Nationally Determined Parameters have been taken into account.
End [from EN 1990:2002 (E)]
1 General
1.1 Scope
1.1.1 Scope of Eurocode
(1)P CEN/TS MEMBR applies to the design of buildings and structural works using technical
membrane materials. It complies with the principles and requirements for the safety and
serviceability of structures - the basis of the design and verification are given in EN 1990 – Basis
of structural design.
(2)P CEN/TS MEMBR is only concerned with the requirements for resistance, serviceability,
durability and fire resistance of membrane structures. Other requirements, e.g. concerning thermal
or sound insulation, are not considered.
(3)P CEN/TS MEMBR is intended to be used in conjunction with
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
4
see Art.3.3 and Art.12 of the CPD, as well as 4.2, 4.3.1, 4.3.2 and 5.2 of ID 1.
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EN 1996
EN 1999
Eurocode 6:
Eurocode 9:
Design of masonry structures
Design of aluminium structures
(4)P CEN/TS MEMBR is subdivided in various parts:
Part 1. General rules and rules for buildings
Part 2. General rules - structural fire design
Part 3. Strength and stability of membrane structures
Part 4. Design of joints
1.1.2 Scope of Part 1 of Eurocode […] gives basic design rules for […]
(1)P The Part 1 of Eurocode ... gives basic design rules for ...
(2)P The following subjects are dealt with in Part 1:
Section 1: General
Section 2: Basis of design
NOTE Sections 1 and 2 provide additional clauses to those given in EN 1990 “Basis of structural
design”.
Section 3: Materials
Section 4: Durability
Section 5: Structural analysis
Section 6: Ultimate limit states
Section 7: Serviceability limit states
NOTE for drafters: the following paragraphs (3) to (6) are optional. If you choose to write them,
try to give useful information (i.e. not only repeat the title).
(3)P Section 3 …
(4)P Section 4 …
(5)P Section 5 …
(6)P Section 6 …
(7)P This Part ... does not cover:
-…
- ...
1.2 Normative references
1.2.1 General reference standards
1.2.2 Other reference standards
1.3 Assumptions
1.4 Distinction between principles and application rules
1.5 Terms and definitions
1.5.1 General
1.5.2 Additional terms and definitions used in the present standard
Definitions for section 8
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Anchorage: a device used to secure a membrane or cable to a support.
Bolt rope: the traditional sail making expression used for a keder textile boundary.
Boundary cable: cable at the edge or termination of the membrane.
Cable: flexible linear or curvilinear element acting in tension. Cable may be wire rope, strand or
web.
Cable cuff or cable pocket: the method of wrapping the fabric around a cable at a boundary
condition.
Cable fitting: any accessory used as an attachment to, or support for, a cable.
Clamped seam: a seam made by a series of shaped, overlapping plates that are clamped together
through the fabric by bolting.
Cold spot: area of little or no adhesion.
Eyelet: a metal ring used to reinforce a small round hole in the membrane for threading a lace,
string, or rope through.
Fabric assembly: a panel of membrane material fabricated from one or more pieces of fabric
having seams and edge and/or connections details incorporated in the finished structure.
Field joint: a connection made on site between two or more pieces of fabric.
Fuse: melt with intense heat, so as to join.
Grommet: a protective eyelet in a hole that a rope or cable passes through.
High point: commonly used expression for a radially patterned conical structure with elevated
mid-ring.
Keder: encased cable edge treatment for membrane surfaces. Either used in conjunction with
grooved profile extrusions or with plates, for connecting to rigid boundaries, corner plates and
boundary cables.
Membrane: tensile surface material
Membrane liner: an interior fabric or film used for decorative, acoustical, thermal insulation or
other non-structural purposes.
Ridge cable: a concave upward cable usually used to resist downward loads.
Seam: a joining of two or more pieces of membrane material.
Sew: join, fasten or repair making stitches with a needle and thread or a sewing machine.
Stay: a tensile support component usually connecting a boundary corner to the foundations.
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Stitch: a loop of thread or yarn resulting from a single pass or movement of the needle in sewing.
Strip: a long, narrow piece of cloth, paper, steel or other material in the form of narrow flat bar.
Tensioning devices: include items fixing the fabric to its support such as roping, edge cables,
fixing profiles, corners, turnbuckles, shackles and so on.
Tie: an axial structural component capable of resisting tensile but not compressive force or
bending.
Turnbuckle: device composed of a doubly threaded cylinder commonly used to provide length
adjustment of cables.
Valley cable: a concave downward cable usually used to resist upward loads.
1.6 Symbols
[NBN-EN-1990] For the purposes of this European Standard, the following symbols apply.
NOTE: The notation used is based on ISO 3898:1987
Latin upper case letters
A
E
F
G
P
Q
Accidental action
Effect of actions
Action
Permanent action
Relevant representative value of a prestressing action (see EN 1992 to EN 1996 and EN
1998 to EN 1999)
Variable action
Greek lower case letters
γ_Partial factor (safety or serviceability)
…
Notations for section 6
n23 average value of tensile strength at 23 °C
Xn23: nominal tensile strength at 23°C
Rd design value of resistance
Sd design value of membrane stress
γM general partial factor
γMi particular partial factor
Ai reduction factors
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2 Basis of design
2.1 Requirements
2.1.1 Basic requirements
[NBN-EN-1990]
(1)P The design of membrane structures shall be in accordance with the general rules given in
EN1990.
(2)P The supplementary provisions for membrane structures given in this section shall also be
applied. or
(2) The supplementary provisions for membrane structures given in this section should also be
applied.
Comment: what are the supplementary provisions?
(3) The basic requirements of EN 1990 Section 2 are deemed to be satisfied for membrane
structures when the following are applied together:
– limit state design in conjunction with the partial factor method in accordance with
EN 1990,
– actions in accordance with EN 1991,
– combination of actions in accordance with EN1990,
– the principles and rules of application given in this Standard, and
– resistances, durability and serviceability in accordance with this Standard.
2.1.2 Reliability management
(1) The rules for reliability management are given in EN 1990 Section 2.
(2) A design using the partial factors given in this Eurocode (see 2.4) and the partial factors given
in the EN 1990 annexes is considered to lead to a structure associated with reliability Class RC2.
(3) When different levels of reliability are required, these levels should be preferably achieved by
an appropriate choice of quality management in design and execution, according to EN 1990:2002
Annex C.
2.1.3 Design working life, durability and robustness
[NBN-EN-1990]
Comment: There is nothing about robustness. A reference to redundancy suits.
2.1.3.1 General
(1)P Depending upon the type of action affecting durability and the design working life given in
EN 1990:2002 Section 2 membrane structures shall be
– designed for corrosion (see EN 1993:2005, EN 1999:2007-4)
– detailed for sufficient fatigue life (see EN 1993:2005-1-4, EN 1999:2007-1-3)
– designed for wearing
– designed for accidental actions (see EN 1991-1-7)
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–
inspected and maintained
2.1.3.2 Design working life for buildings
(1) The rules for design working life are given in EN 1990:2002 Section 2.3
2.1.3.3 Durability
(1) The rules for durability are given in EN 1990:2002 Section 2.4
2.2 Principles of limit state design
(1) The rules for limit state design are given in EN 1990:2002 Section 3
2.3 Basic variables
2.3.1 Actions and environmental influences
2.3.1.1 General
(1) The rules for actions and environmental influences are given in EN 1990:2002 Section 4.1.
(2) Actions to be used in design may be obtained from the relevant parts of EN 1991. For the
combination of actions and partial factors of actions see Annex A to EN 1990:2002.
(3) In the absence of data specific to the geometry of the structure, wind loads should be derived
from …
NOTE 1: The relevant parts of EN 1991 for use in design include:
EN 1991-1.1 Densities, self-weight and imposed loads
EN 1991-1.2 Fire actions
EN 1991-1.3 Snow loads
EN 1991-1.4 Wind loads
EN 1991-1.5 Thermal actions
EN 1991-1.6 Actions during execution
EN 1991-1.7 Accidental actions
NOTE 2: The National Annex may define actions for particular regional or climatic or accidental
situations.
Comment: is "EN 1991-1.4 Wind loads" a relevant part for use in design?
2.3.1.2 Load-duration classes
[from BS EN 1995-1-1:2004]
(1)P The load-duration classes are characterised by the effect of a constant load acting for a
certain period of time in the life of the structure. For a variable action the appropriate class shall
be determined on the basis of an estimate of the typical variation of the load with time.
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(2)P Actions shall be assigned to one of the load-duration classes given in Table 2.1 for strength
and stiffness calculations.
Table 2.1 – Load-duration classes
Load-duration class Order of accumulated duration of characteristic load
Permanent
more than 10 years
Long-term
6 months – 10 years
Medium-term
1 week – 6 months
Short-term
less than 1 week
Instantaneous
Note: Since climatic loads (snow, wind) vary between countries, the assignment of load-duration
classes may be specified in the National annex.
2.3.1.3 Prestress
(1)P The prestress considered in this Eurocode is applied mechanically by fabric compensation.
Comment: "Prestress": ..."and tension" added to (1)P
(2) Provisions concerning prestress are found in 5.1(?) 6.2(?)
Comment: It has to be mentioned that there should be prestress. Identify the prestress for the main
structure and for the membrane. In section 5? A specific appendix to Eurocode 1? May be an
appendix to this Eurocode? First clarify the text, next decide where to place it. Bernd Stimpfle
will prepare this issue.
2.3.2 Material and product properties
2.3.2.1 General
(1) The rules for material and product properties are given in EN 1990:2002 Section 4.2.
(2) Properties of materials and construction products should be those specified in the relevant Ens,
hENs or ETAs, unless otherwise indicated in this standard.
2.3.2.2 Creep
(1) Creep is a time-dependent property of coated fabrics and foils. The effect of creep should
generally be taken into account for the verification of serviceability limit states.
(2) The effects of creep should be considered at ultimate limit states only where their effects are
significant, for example in the verification of ultimate limit states of stability. In other cases these
effects need not be considered for ultimate limit states.
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2.3.3 Deformations of coated fabrics and foils
Comment: 2.3.3 Deformations of coated and uncoated fabrics and foils
(1)P The consequences of deformation due to creep shall be considered in design.
2.3.4 Geometric Data
(1) The rules for geometric data to be used for design are given in EN 1990:2002 Section 4.3.
2.4 Verification by the partial factor method
2.4.1 General
(1) The rules for verification by the partial factor method are given in EN 1990:2002 Section 6.
2.4.2 Design value of material properties
(1)P For the design of membrane structures characteristic values Xk or nominal values Xn of
material properties shall be used as indicated in this Eurocode.
(2)P The design value for a material property is obtained by dividing its characteristic value by a
relevant partial factor for materials, M.
2.4.3 Design value of geometric data
(1) Geometrical data may be taken as nominal values from product standards hEN for the
execution.
2.4.4 Design resistances
2.4.4.1 Partial factors for prestress
(1) Prestress in most situations is intended to be favourable and for the ultimate limit state
verification the value of P,fav should be used. The design value of prestress may be based on the
mean value of prestressing force (see EN 1990:2002 Section 4.1.2) Note for CEN250 WG5 –
definition/usage of prestress in EN 1990:2002 (EC0) means that this last statement is not correct
and needs modifying.
Comment: A minimum and maximum value should be specified, depending on the shape and the
material.
EN 1990:2002 Section 4.1.2
(6) Prestressing (P) should be classified as a permanent action caused by either
controlled forces and/or controlled deformations imposed on a structure. These
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types of prestress should be distinguished from each other as relevant (e.g.
prestress by tendons, prestress by imposed deformation at supports).
NOTE The characteristic values of prestress, at a given time t, may be an upper
value Pk,sup(t) and a lower value Pk,inf(t). For ultimate limit states, a mean value
Pm(t) can be used. Detailed information is given in EN 1992 to EN 1996 and EN
1999.
[ENV 1992-1-1:1992 Table 2.2]
2.4.4.2
2.4.5 Combination of actions
(1) The general formats for combinations of actions for the ultimate and serviceability limit states
are given in EN 1990:2002 Section 6.
Note: Detailed expressions for combinations of actions are given in the normative annexes of EN
1990:2002, i.e. Annex A1 Buildings, etc. with relevant recommended values for partial factors
and representative values of actions in the notes.
(2) For each permanent action either the lower or upper design value (whichever gives the more
unfavourable effect) should be applied throughout the structure.
2.4.6 Verification of static equilibrium (EQU)
(1) The reliability format for the verification of static equilibrium in Table 1.2 (A) in Annex A of
EN 1990:2002 also applies to design situations equivalent to (EQU), e.g. for the design of holding
down anchors.
2.5 Design assisted by testing
(1) The design of structures or structural elements may be assisted by testing.
NOTE: Information is given in Section 5 and Annex D of EN 1990:2002.
3 Materials
[cfr 4.2 in NBN-EN-1990, Example content from looking @ EC9]
3.1 General
3.2 Coated Fabrics
3.2.1 Range of Materials
3.2.2 Materials Properties
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3.2.3 Dimensions, mass, tolerances
3.2.4 Design values of material constants
3.3 Uncoated Fabrics
3.3.1 Range of Materials
3.3.2 Materials Properties
3.3.3 Dimensions, mass, tolerances
3.3.4 Design values of material constants
3.4 Films
Comment: 3.4 Films or foils?
3.4.1 Range of Materials
3.4.2 Materials Properties
3.4.3 Dimensions, mass, tolerances
3.4.4 Design values of material constants
3.5 Connecting devices
(steel, aluminum, FEP tape, silicon tape, wire ropes, threads, glues)
3.6 Structural Elements
(steel, aluminum, etc)
(1)P Material property values shall be determined from standardised tests performed under
specified conditions. A conversion factor shall be applied where it is necessary to convert the test
results into values which can be assumed to represent the behaviour of the material or product in
the structure or the ground.
(2) The structural stiffness parameters (e.g. moduli of elasticity, creep coefficients) and thermal
expansion coefficients should be represented by a mean value. Different values should be used to
take into account the duration of the load.
(3)P Where a partial factor for materials or products is needed, a conservative value shall be used,
unless suitable statistical information exists to assess the reliability of the value chosen.
4 Durability
4.1 General
[Refer to EC0 2.3.3, durability can be measured according to EN…
See EC 2 section 4.1]
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5 Basis of Structural analysis
5.1 General
Comment: what does the word "appropriate" in (2)P, (6)P and (9) mean?
(1)P The purpose of structural analysis is to establish the distribution of either internal forces and
moments, or stresses, strains, and displacements, over the whole or part of the structure.
Additional local analysis shall be carried out where necessary.
(2)P Analysis shall be based upon calculation models of the structure that are appropriate for the
limit state under consideration.
(3)P For each relevant limit state verification, a calculation model of the structure shall be set up
from:
– an appropriate description of the structure, the materials from which it is made, and the
relevant environment of its location;
– the behaviour of the whole or parts of the structure, related to the relevant limit states;
– the actions and how they are imposed.
(4)P The general arrangement of the structure and the interaction and connection of its various
parts shall be such as to give appropriate stability and robustness during construction and use.
(5)P The method used for the analysis shall be consistent with the design assumptions.
(6)P Analyses shall be carried out using idealisations of both the geometry and the behaviour of
the structure. The idealisations selected shall be appropriate to the problem being considered.
(7)P The effect of geometry and properties of the structure on its behaviour at each stage of
construction shall be considered in the design.
(8)P The model for the calculation of internal forces in the structure or in part of the structure
shall take into account the displacements and rotations of the connections.
(9) The calculation model and basic assumptions should reflect the structural behaviour at the
relevant limit state with appropriate accuracy and reflect the anticipated type of behaviour
materials and connections.
5.2 Structural modelling for analysis
5.2.1 Structural modelling and basic assumptions
5.2.2 Form-finding
5.2.3 Modelling of seams
5.2.4 Modelling of connections
5.2.5 Patterning
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5.2.6 Ground-structure interaction
5.2.7 Wind-structure interaction
5.2.8 …
5.3 Global analysis
5.3.1 Effects of deformed geometry of the structure
5.3.2 Structural stability of supporting structure
5.4 Imperfections
5.4.1 Basis
5.4.2 Imperfections for global analysis of frames
5.4.3 Member imperfections
5.5 Methods of analysis
5.5.1 General
5.5.2 Elastic global analysis
5.5.3 Viscoelastic global analysis
6 Ultimate limit states (ULS)
Comment: DIN18204 not really compatible with the Eurocodes. So we keep the Eurocode
approach.
6.1 General
(1) The partial factors γM as defined in Section 2 should be applied to the various characteristic
values of resistance in this section as follows:
– resistance of material γM0
– resistance of joints γM1
NOTE: Partial factors M for membrane structures may be defined in the National Annex. The
following numerical values are recommended for membrane structures:
M0 = 1,40
M1 = 1,50
(2) The reduction factors A as defined in Section 2 should be applied to the various characteristic
values of resistance in this section as follows:
– reduction factor biaxial effects A0
– reduction factor long term effects A1
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– reduction factor environmental effects A2
– reduction factor temperature effects A3
Comment: How to get the A-factors? Give recommended values for the worst case (usable for
small structures). If better values are available from tests, it is allowed to use them. For standard
materials standard reduction factors can be given in annexe. For new materials further
investigation is required.
NOTE: Reduction factors A for membrane structures are typically derived from tests.
Recommended values may be defined in the National Annex.
(3) The nominal tensile strength Xn23 as defined in Section 2 is derived from uniaxial material or
joint tests. It is the 5% fractile result of a test with at least 5 specimens.
In the absence of such test the nominal tensile strength can be determined with the following
equations:
for material: Xn23= 0.868 * n23 (this corresponds to a variation coefficient of 0.06)
for joints: Xn23= 0.802 * n23 (this corresponds to a variation coefficient of 0.12)
6.2 Resistance of material and joints
6.2.1 General
(1) The design value of an action effect in the material shall not exceed the corresponding design
resistance and if several action effects act simultaneously the combined effect shall not exceed the
resistance for that combination.
(2) Due to the geometrical nonlinear behavior it is not appropriate to combine action effects, that's
why the effect of combined actions needs to be determined.
6.2.2 Design Resistance Long Term Load
The design resistance for material and joints Rd is calculated with the following equations:
Rd= Xn23 / (mi * A0 * A1 * A2 * A3)
NOTE: Snow load is assumed to be a long term load.
6.2.3 Design Resistance Short Term Load Cold Climate
The design resistance for material and joints Rd is calculated with the following equations:
Rd= Xn23 / (mi * A0 * A2)
6.2.4 Design Resistance Short Term Load Warm Climate
The design resistance for material and joints Rd is calculated with the following equations:
Rd= Xn23 / (mi * A0 * A2 * A3)
NOTE: Areas with warm climate are regions without snow load.
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6.2.5 Membrane Stress Verification
(1) The design value of the membrane stress Sd in each area of the material shall satisfy:
Sd / Rd ≤ 1.0
(2) If parts of the membrane surface are reinforced with an additional layer of membrane, the
design resistance is increased by 50% unless a more precise evaluation by tests has been
performed.
Comment: an additional layer of membrane increases only 50% the design resistance?
6.2.6 Shear
Comment: Shear is linked to wrinkling. Wrinkling is important for the definition of the limit
states. Can this condition be specified in an informative annexe?
6.2.7 Tearing
6.3 Connections
6.4 Design of ... subjected to
7 Serviceability limit states (SLS)
7.1 General
(1) A membrane structure shall be designed and constructed such that all relevant serviceability
criteria are satisfied.
(2) The basic requirements for serviceability limit states are given in 3.4 of EN 1990.
(3) Any serviceability limit state and the associated loading and analysis model should be
specified for a project.
7.2 Serviceability limit states for buildings
7.2.1 Vertical deflections
(1) With reference to EN 1990 – Annex A1.4 limits for vertical deflections according to Figure
A1.1 should be specified for each project and agreed with the client.
NOTE: The National Annex may specify the limits.
7.2.2 Horizontal deflections
(1) With reference to EN 1990 – Annex A1.4 limits for horizontal deflections according to Figure
A1.2 should be specified for each project and agreed with the client.
NOTE: The National Annex may specify the limits.
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7.2.3 Distance to other parts
(1) Because a load bearing membrane can be subject to considerable deflections, care shall be
taken to ensure that no structural or other parts may hinder the deformation, if this has not been
taken into account in the analysis.
7.2.4 Safeguards
(1) In case of collapse of the membrane all load bearing components shall remain itself stable.
(2) In so far as rigid load bearing components (e.g. masts, supports, etc.) are restraint solely by
membrane, the overturning of such components in the event of a one-sided removal of the
membrane shall be prevented by additional measures, and the degree of freedom of movement in
the operation condition shall remain intact.
7.2.5 Post tensioning
(1) If not taken into account during the design, design measures which enable post tensioning
should be incorporated to compensate creep of the membrane.
7.2.6 Ponding
(1) Under snow and rain actions ponding should be avoided in membrane structures.
(2) If ponding cannot be avoided in all parts of a membrane structure, a detailed analysis with
realistic snow ice and water accumulation needs to be carried out, to verify the serviceability as
well as the structural integrity.
(3) For ponding analyses the lower limits for the elastic constants should be used.
7.2.7 Wrinkling
(1) In the prestress state the membrane surface should be free of wrinkles.
Annex: Some typical reduction factors
In various tests reduction factors A have been determined. The following list is giving the
bandwidth for these reduction factors:
A0 (biaxial)
ranges between 1.0 and 1.2. If for the governing load case the stress is mainly in one direction 1.0
is appropriate.
A1 (long term)
ranges for PVC/PES typically between 1.4 and 1.7
and for PTFE/Glass around 2.1
A2 (environment)
Typically 1.1 except for stitched seams (1.4)
A3 (temperature)
ranges for PVC/PES typically between 1.2 and 1.5
and for PTFE/Glass around 1.1
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7.3 Tear control
7.3.1 General considerations
7.3.2 Minimum reinforcement areas
7.3.3 Control of tearing without direct calculation
7.3.4 Calculation of tear propagation
7.3.5 ...
8 Details/Connections
8.1 General
(1)P Consistency with the model of the structure, whether geometric, physical or numerical:
The detail elements shall be able to respect the load path geometry whenever external loading
conditions change. They shall be fluently integrated into the geometry of the system. Space
enough shall be provided. Details and connection points shall follow exactly the system line
geometry of the suspension points. Eccentricities shall be avoided in order to guarantee the correct
shape of the total system.
(2)P Appearance: A general view of the whole design is needed so as to decide on the legibility
of the structure, to determine the visual quality of all the elements. Membrane structure details
shall be simple, flexible, of minimal configuration and expressing their own textile characteristics
that are so different to other building technologies. Details shall also be coordinated in scale with
the structure and in coherence with the material used.
(3)P Strength: Transfer internal forces and applied loads through the membrane field and to the
supporting structure accommodating resistance and geometry. Eccentricities in the connection
details are not desirable but shall be considered. Loads may be static, dynamic, repeated or
sustained. Resistance to failure of cables and fittings elements must be guaranteed by the
manufacturers. The minimum value of this breaking strength should be clearly indicated.
Comment: Cfr. ULS?
(4)P Flexibility: The connections shall consider the requirements allowing large displacements,
rotations and long-term effects of membrane for elongation and flexure in the direction of the
joint.
(5)P Adjustability and re-tensioning: Due to membrane creeping effects, it is essential to give a
sufficient scope to re-tensioning and pre-stress preservation during the life span of the structure.
Comment: Some structures don’t have the possibility to re-tension. Cfr. prestress: if there is no
possibility to re-tension, estimate the creep and apply a higher initial prestress (to be included in
the compensation)
(6)P Security and redundancy: Membrane skins are liable to vandalism. Designs shall be carried
out so that, in the event of failure of one or more membrane fields within a roof, the supporting
system does not collapse, and heavy elements such as masts are retained from falling down by a
safety rigging.
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Potential failure should not result in disproportionate damages and security elements may need to
be added into the structural system.
(7)P Protection of the membrane: Damage to fabric shall be avoided.
All care should be taken during detailing in such a way that fabric in contact with the structure
and fittings (edge ropes, stays, clamp plates etc.) shall not be damaged, even with cyclic loading
and large movements of the fabric. The supporting elements shall be free of rough spots, sharp
edges, droplets following hot dip galvanization drying process or other defects that may injure the
membrane material.
(8)P Water tightness:
(9)P Fire resistance:
(10)P Buildability: During installation, particular movements and rotations can be required at the
connection points.
Quite often, such kinetic displacements are different from the structural ones, needed once the
final position has been reached.
These displacements still have to be accommodated in the final element so that the structure can
be assembled and pre-stressed.
During this erection phase, stresses initially tend to mainly flow through the membrane rather than
through the edge ropes which remain slack until the membrane reaches its tensioned position.
Thus the weight of the fabric is carried solely by its connection to the corner.
Corners themselves have a particular mass that shall be taken into account during the installation
procedure. Temporary support may be needed to hold the corner in place and properly direct it to
its rough final angle.
Flexible connections are needed to provide enough degrees of freedom during installation because
the membrane is not in its final position and before hoisting, is at a position determined by
gravity. This can, for instance, cause a 180° rotation of a corner during lifting of the fabric.
Installation devices are needed to enable the lifting, stretching and pre-stressing of the membrane.
The corners shall be provided with means of attachment such as spare holes, for instance.
(11)P Durability over the design lifespan of the structure: Details should function satisfactorily
throughout their lifetime. Sub-elements shall be designed to withstand the effects of long term
loading, accounting for the creep and fatigue characteristics of the membrane and other structural
materials. Make sure that the prescribed and definitely chosen materials for clamping and
detailing are of the same durability as the fabric or film and provide coherent weather resistance,
rustproof protection.
(12)P Maintenance and accessibility:
8.2 Membrane-membrane
8.2.1 Seams
(1) Membrane seams should be designed and fabricated so that they meet the following strength
criteria:
a) at 20ºC the seam should resist a test load equal to 100% of the minimum specified tensile
strength of the fabric when tested in accordance with XXXX.
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b) at 20ºC the seam should resist a continuous test load equal to 200% of the minimum service
load for a minimum of 4 h and exhibit less than 3 mm slippage.
c) at 70ºC the seam should resist a continuous test load equal to 100% of the maximum service
load for a minimum of 4 h.
(2) The effective breaking strength of membranes using seam constructions that do not comply
with the aforementioned requirements, should be reduced to the strength of the seams.
(3) As a minimum, mechanical membrane joints and other seams should be designed to have a
breaking strength greater than 200% of the maximum stress under service load.
(4) Apart from the aforementioned requirements, the seams make an important contribution to the
final configuration of the whole. The material is translucent and the joints are viewed against the
light. Properly planned, these enhance the clarity that stems from the flow of forces, main slopes
and spatial trends.
8.2.2 Welds
(1) Welded seams should be fully sealed, with no cold spots.
(2) For PVC coated polyester fabrics the following methods are available:
(3) The overlap of the welding will be oriented as much as possible according to the direction of
water flow.
(4) The membrane assembler should be prepared to demonstrate that the proposed manufacturing
process for a particular seam intended for a particular engineered application will produce reliable
finished assemblies meeting the project requirements. The welding-machines are to be operated
by trained and experienced users. They must include monitoring devices allowing to guaranty
tuning evenness and welding quality such as power, welding delay, electrode cooling control.
Note that welding-machines should include a thickness gauge in case of more than Type II
PES/PVC assembling.
a) High-frequency welding, shop only
b) Hot wedge welding, shop only
c) Hot air welding, shop and site. Hot air welding needs an experienced manufacturer and is
most appropriate for straight seams. It is not recommended for permanent structures. It is
possible to apply on site but on condition that a clean and dry environment is available.
(5) For PTFE coated glass fabrics the following methods are available:
a) Heat welding process in the shop
b) Heated irons, hand held, for site patch repairs.
(6) Welding width:
- For High Tenacity Polyester PVC coated:
3 cm for type 1 fabric,
4 cm for type 2 fabric,
4 cm for type 3 fabric,
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4 cm for type 4 fabric,
- For Glass Fiber PTFE sintered: 7 cm minimum
(7) Electrode bar length:
- coherent with the welding-machine and the fabric to be assembled.
- coherent with the edge curvature of the seam. The welding step should avoid more than
0,5 misalignment.
(8) Welding cross-over: the operator must carry on the secondary welds apart the main one at
first and then the main one.
(9) Welding controls: they must be carried on over a representative sample of the active fabric
reel. At the cutting phase, test samples must be taken and marked, three times each 200 linear
meter of welding length.
(10) Tests must be carried on during the welding phase at the same rate as above. These samples
are to be welded with the same machine and tuning as the operating one on the warp and weft
directions.
One among these samples is submitted to a manual pealing test enabling to verify the welding
strength and uniformity.
A second one is to be marked and stored, and a third one is to be tested in tension rupture under
ambient temperature according to usual procedure XXXX
(11) Testing of mechanical properties: The mechanical properties of the welded seams will be
verified regularly during the whole manufacturing. The test results will be reported on selfmonitoring sheets which will be made available to the designer and the technical controller.
(12) For outside laboratory control, a sample will be taken from the fabric cutting process all
500m minimum. This control is necessary for all structures of an overall surface larger than
500m2.
Control of the behaviour with cold and hot welds should be performed according to XXXX.
(13) In shop test: long time test on a welded sample with ambient temperature. Tests should be
made on warp and weft directions. The test results will be reported on self-monitoring sheets
which will be made available to the designer and the technical controller.
(14) Control of aspect of welds: welds must not show ripples or greater than 1 mm alignment
defects. Crash differences caused by the electrode must not be visible to the naked eye for welds
of common assemblies. Special care is requested in the overlapping of welds and in the treatment
of residual rejection of PVC occurring at the weld seam. The resulting work must have a regular
aspect.
(15) Some scores and a few small finishing can be made punctually by hot air with a welding
machine "Leister" like. This work must be particularly treated and controlled.
8.2.3 Sewing
(1) Seams must be performed with a thread which should be protected against UV and preferably
of the same nature as the fabric mesh (polyester).
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(2) In the case of an assembly by only sewing, it must be sized to pass the efforts with a safety
factor of 2.5. (2 stiches ½ per cm)
(3) The resistance of the seams by sewing must be justified by an internal testing protocol to be
proposed according to the importance of the work.
Refer to ISO 4915 and ISO 4916.
8.2.4 Gluing in the shop or on site for making patch repairs
8.2.5 Grommeting and lacing on site for easiness of erection and demountability
(1) Realization of a triple folds hem (three layers) with edge keder of 7mm diameter.
Width of hem with 4cm minimum. Installation of grommets strictly against the keder. Inner
diameter of grommets, 18mm minimum punched without ease by pneumatic or hydraulic
machine.
Nature: brass or stainless steel with claws.
Pitch of 150mm or determined by technical studies.
(2) The resistance of the grommets strip connections must be justified by tests. These tests will be
documented on a record of less than 5 years corresponding to a minimum test on samples of 3
grommets. These tests will focus on 3 samples submitted by the concerned production unit.
8.2.6 Clamping
(1) This type of connection is installed on site, has a strong visual appearance and is used to join
large prefabricated membrane panels together. It can be made out of materials capable of taking
the load e.g. wood, steel, aluminium or plastic.
(2) The strips need to allow for straining of the membrane and their length is depending on the
curvature along the seam. The distance between the bolts is related to the out-of-plane stiffness of
the clamping plates. (The more frequent the bolts, the less the clamping plate stiffness that will be
needed).
(3) The transfer of load between the membrane and the boundary line must occur by the keder
bearing against the edge of the clamp plates. The keder needs to be held continuously along its
full length. The load should not be transmitted directly by friction or to the bolts. (The mechanism
relies on the holes through the fabric being large enough to give good clearance around the bolt.
Such a clearance has to allow for construction tolerances).
(4) Realization of a triple folds hem (three layers) with edge keder of 7mm diameter.
Width of hem with 4cm minimum.
(5) Clamp plates must not be positioned against each other.
(6) The bolts will be in stainless steel for stainless steel clamps and galvanized or electrogalvanized for aluminium clamps.
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(7) The resistance of the clamped hems must be justified in the same conditions as for the
grommet strips.
(8) Plates without grommets can be designed as follows:
- aluminium or stainless steel plates of 40 x 4mm or 30 x 3mm,
- unit length of 130mm,
- 2  10mm bores with 70mm step for the outer plate,
- 2  10mm square stamp punches, with 70mm step for inner plate,
- 2 JAPY  8mm bolt reference.
(9) Eyelet plate can be designed as follows:
- aluminium or stainless steel plates of 40 x 4mm or 30 x 3mm,
- unit length of 135mm,
- 2  16mm inner diameter bores with 70mm step, for the filling of both the polyester rope
and the elastic one,
- 4  4,5mm bores aside the  16mm bores for the assembly of the plates on the fabric,
- 4 POP  4,2mm aluminium rivets.
(10) All 16mm bore edges will be neatly plated down.
8.2.7 Fusing or melting
8.2.8 Combination seams
(1) Seams which use a combination of both stitching and welding can provide an extra level of
security at higher temperature or forces applied at 90° to the seam edge. They only apply to
stitchable materials – for example PVC coated polyester and woven PTFE cloth but not PTFE
coated glass.
8.3 Membrane to others
(1) Membrane to non-membrane connection details should be configured so as to minimize stress
concentrations in the fabric and minimize fabric wear and damage over the life of the structure.
(2) The strength of the constitutive elements of the tensioning devices (cables, turnbuckles,
corners…) should be justified with reference to experimental breaking loads guaranteed by the
manufacturers of these elements. The safety coefficient in connection with failure is 2 for cables
and 2,5 for the other parts.
8.3.1 Edges
(1) The mechanical resistance of edges should be justified with reference to tests. The safety
coefficient in relation to extreme combinations should be at least equal to 2,5.
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(2) Flexible curved edges should allow the prestressing of the fabric as the result of a tension
force developing in the boundary element.
(3) Cable in a pocket welded continuously along the membrane edge is restricted by the length of
the seam. The angle between the upper and lower surfaces of pocket depends on the width of the
pocket in relation to the diameter of the cable because it should be large enough to avoid large
peeling forces along the line where the pocket is welded to the membrane.
(4) Cable sheath can be realized by welding or welding + double stitching of a band over the main
canvas, with the strip forming the sheath cut in the fabric bias so as to provide extra elasticity for
the edge curvature.
The width of the sheath must be at least equal to 4 times the diameter of the cable and the ends of
sheath should be strengthened by a fold or a strap sewn and flaring.
(5) Edge cable outside the membrane when tangential forces become large and the concentration
of such force at the corners becomes critical.
(6) Belts can be stitched or welded along the perimeter to carry tangential membrane forces and
prevent from movements of the fabric along the cable prone to abrasion. They can be attached to
the inside or outside of the cable pocket. Belts on top of the membrane have to be covered so as to
protect them from UV and to avoid the growth of moss. Belts have to be compensated for their
creep behaviour and require an “initial stretch” before their installation.
(7) Rigid edges are edges where the fabric is held continuously by a supporting structure having
much greater lateral stiffness compared with that of the fabric:
- Tube in a cable pocket (for PVC coated polyester). The points mentioned for cable
pockets are valid here. Forces travel perpendicularly into the tube. Movements along the
tube have to be prevented and the angle for the pocket has to be chosen to be small enough
to limit “peeling” forces in the seam.
- Laced to a channel or section. Forces are led perpendicularly into the section, and because
of the triangular lacing, tangential forces are taken up too.
- Clamped. A single layer of clamp plates can be used to clamp a membrane edge directly
onto a beam boundary. Refer to 8.2.5
8.3.2 Field supports
(1) Linear supports: suspended or supported ridges and stretched or pushed down valleys
produced by cables or sections.
(2) Point field supports: supported or suspended high points and tied or pushed down low points.
(3) If a ring shaped element is used to control the level of stresses, the diameter of the ring will
depend upon the strength of the fabric and the total load to be carried into the support. The
designer may choose to add a reinforcing layer locally to the membrane as a means of reducing
the ring’s diameter. To make the ring watertight, it can be covered in different ways. Sometimes it
is used for ventilation. When the internal support is used as a low point, it will gather rainwater
and snow unless drainage is provided.
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(4) In the vicinity of the summits, the seams are necessarily radiant. They are assembled by H.F.
welding, peripheral and radiant.
(5) To allow efforts paths, it may be necessary to strengthen the main fabric by additional layers.
They must be defined by the technical office. The total number of folds should be limited to 5
maximum.
(6) Another way of decreasing the stress in the fabric is making use of the so-called “butterfly”
solution which originates from soap film form finding. A sequence of cable loops form a closed
continuous boundary lying within the membrane’s surface.
8.3.3 Corners
(1) Stiff corners elements like steel plates should be avoided, or their use limited as much as
possible, so that the membrane arrives as closely as possible to its connecting points.
(2) Corner plate set apart from the fabric, and with the fabric and cables separately adjustable
(PVC/Polyester, PTFE/Glass). In the case of small structures, without steel corners, angles must
be reinforced by welding of several folds of complementary fabric. They will be equipped with
anti-sliding straps. A supplementary device will be eventually adapted for assembly phase.
(3) Corner plate clamped to fabric, adjustable cables (PVC/Polyester, PTFE/ Glass)
(4) Corner plate connected with keder profile to fabric, adjustable cables or of fixed length
(PTFE/Glass).
(5) Corner plate clamped to fabric, continuous edge cable (PVC/Polyester)
(6) Corner plate, connection with belts (PVC / Polyester)
8.4 Reinforcements for edges, ridges, valleys, corners, high and low points
(1) In all areas where stress concentrations can occur, the membrane shall be reinforced as
required with additional fabric or belts.
(2) When reinforcing of the membrane or membrane liner is required, it shall consist of either
membrane, metallic or non-metallic cables or non-metallic reinforcing. Such materials shall be of
uniform quality and shall have properties for the intended usage.
(3) The strength of metallic cables shall be determined in accordance with XXXX.
(4) The strength and fire characteristics of non-metallic cable and web elements shall be
determined in accordance with material standards provided by the manufacturer and approved by
the authority having jurisdiction.
(5) The strength and fire characteristics of non-metallic fabric reinforcements of the membrane or
membrane liner shall comply with Sections 3 Materials and 8 Details/Connections.
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(6) The polyester straps will be sewn on a regular basis on strengthened fabric. The chain stitch is
prohibited. Sewing will be parallel to the edges of the strap and respect a guard of at least 7mm.
Each sewing will be properly ended. The waste yarns will be eliminated.
(7) Specific case for the installation of the accessories on PTFE fabric: fibre glass fabrics justify a
particular methodology. Eyelets will be used only exceptionally. Plates, usually aluminium, will
be riveted or bolted. They will come to position themselves in a keder, or passive, or imprisoning
this keder in a gorge. Draw straps sewn directly onto the fibre glass fabric is prohibited. Edge
cables will be used by the same methods as for fabrics polyester PVC. It is common to use outer
cable doubling the rope cables and fixed to those by riders.
8.5 Stays, ties
(1) The cables, galvanized steel, stainless steel or composite, single or multi-strand have pressed
or cast fittings.
(2) For guys, the cables will be provided pre-strained, with certificate of test for all cables with a
diameter greater than or equal to 20mm. A test of crimping on sample to 80% of the breakdown of
the cable may be asked.
8.6 Base plates for masts and anchors: moment resisting, singly or doubly
hinged
(1) Non fabric connections shall provide for the anticipated rotations, shall have enough
adjustability to maintain proper tension forces, shall allow for long-term effects and shall take into
consideration eccentricities.
8.7 Anchors and foundations under tension
(1) The anchorage system shall be designed to distribute individual anchor loads uniformly to the
membrane so as to prevent excessive stress concentration in the membrane. Movements and
rotations of the membrane and/or the membrane structure under load and the changes in direction
of the reaction or load application shall be considered in the design of all anchorages.
(2) The number of tests on place regarding the capacity of anchorages is determined by the
importance of the structure in a measure of 1% of the necessary anchors, with a minimum of three
tests. Every anchor should resist an extraction load, in the direction of the longitudinal axe, at
least equal to the value requested from the designer and mentioned in the calculation report and in
the check-list.
8.7.1 Active anchors (pre-stressed)
8.7.2 Passive anchors
(1) Stakes, hooks, piles, expandable anchors, sheet piles, diaphragm walls, cylindrical and under
reamed shafts, blocks, strips, logs, plates, arrows, tubes, grillages, screws.
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Annex Testing
Scenarios for testing connections have to be established.
Annex Tolerances
Seams: all seams shall be fabricated within the following tolerances when measured over a 3 m
length:
a) seam designed to be less than 50mm wide shall not be less than 1,5mm smaller than specified.
b) seam designed to be 50mm or more wide shall not be less than 3mm smaller than specified.
Other tolerances.
9 Manufacture/Fabrication, handling & packing & Installation
(=Execution in other ECs?)
See EC2, EC3
EC6 – quality of installation affects safety factor
10 Inspection/Maintenance
Control & maintenance of the completed structure (e.g. section 7.7 EC2 Part 1; section 10.7 EC5)
11 Design Assisted by Testing
(cfr 5.2 in NBN-EN-1990)
Annex ? [informative] - Analytical models for stress strain relationship...
?.1 See EN from CEN248 WG4
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