Bsi bs en 12810 2 2003 (2004)

www bzfxw com BRITISH STANDARD BS EN 12810 2 2003 Façade scaffolds made of prefabricated components — Part 2 Particular methods of structural design The European Standard EN 12810 2 2003 has the statu[.]

This British Standard was

published under the authority

of the Standards Policy and

A list of organizations represented on this subcommittee can be obtained on request to its secretary

This standard is published with National annex NA, which gives further information on the use of EN 12810-2:2003 in the UK

Cross-references

The British Standards which implement international or European

publications referred to in this document may be found in the BSI Catalogue

under the section entitled “International Standards Correspondence Index”, or

by using the “Search” facility of the BSI Electronic Catalogue or of British

— aid enquirers to understand the text;

— present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the

Amendments issued since publication

Façade scaffolds made of prefabricated components - Part 2:

Particular methods of structural design

Echafaudages de façade à composants préfabriqués

-Partie 2: Méthodes de conception particulière et

d'évaluation

Fassadengerüste aus vorgefertigten Bauteilen - Teil 2: Besondere Bemessungsverfahren und Nachweise

This European Standard was approved by CEN on 4 September 2003.

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

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

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

EUROPEAN COMMITTEE FOR STANDARDIZATION

C O M I T É E U R O P É E N D E N O R M A L I S A T I O N

E U R O P Ä I S C H E S K O M I T E E F Ü R N O R M U N G

Management Centre: rue de Stassart, 36 B-1050 Brussels

page

1 Scope 4

2 Normative references 4

3 Terms and definitions 4

4 Structural design 4

4.1 General 4

4.2 Models for structural analysis 6

4.3 Tests on configurations and connection devices 10

4.3.1 Tests for stiffness and resistance 10

4.3.2 Vibration test 10

4.4 Tests on a representative section of a system configuration 11

4.4.1 General 11

4.4.2 Type 1 test for verification of significant load displacement behaviour 11

4.4.3 Type 2 test for the verification of the elastic buckling load factor αcr 13

4.4.3.1 Test assembly 13

4.4.3.2 Test procedure 13

4.4.3.3 Validation of αcr 14

Annex A (normative) Typical tests for connection devices and configurations 15

Annex B (normative) Drop tests for platforms and their supports 21

Annex C (normative) Repeated loading tests for welded aluminium treads 23

Bibliography 24

EN 12810-2:2003 (E)

Foreword

This document (EN 12810-2:2003) has been prepared by Technical Committee CEN/TC 53 “Temporary works

equipment”, the secretariat of which is held by DIN

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 June 2004, and conflicting national standards shall be withdrawn at the latest by

June 2004

Annexes A, B and C are normative

This European Standard will supersede the European Harmonisation document HD 1000:1988 "Service and

working scaffolds made of prefabricated elements; Materials, dimensions, design loads and safety requirements"

This European Standard is one of a series of standards as listed below

EN 12810-1, Façade scaffolds made of prefabricated elements — Part 1: Product specifications

EN 12810-2, Façade scaffolds made of prefabricated elements — Part 2: Particular methods of structural design

EN 12811-1, Temporary works equipment — Part 1: Scaffolds — Performance requirements and general design

prEN 12811-2, Temporary works equipment — Part 2: Information on materials

EN 12811-3:2002, Temporary works equipment — Part 3: Load Testing

According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following

countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,

France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal,

Slovakia, Spain, Sweden, Switzerland and the United Kingdom

1 Scope

This European standard applies to façade scaffold systems conforming with EN 12810-1 It defines rules for the

structural analysis and design of these systems by calculation and testing, in addition to those defined in

EN 12811-1,prEN 12811-2, EN 12811-3 and EN 12810-1

Basic requirements are given in ENV 1993-1-1 and ENV 1999-1-1

2 Normative references

This European Standard incorporates by dated or undated reference, provisions from other publications These

normative references are cited at the appropriate places in the text and the publications are listed hereafter For

dated references, subsequent amendments to or revisions of any of these publications apply to this European

Standard only when incorporated in it by amendment or revision For undated references the latest edition of the

publication referred to applies (including amendments)

EN 12810-1:2003, Façade scaffolds made of prefabricated components — Part 1: Product specifications

EN 12811-1, Temporary works equipment — Part 1: Scaffolds — Performance requirements and general design

prEN 12811-2, Temporary works equipment — Part 2: Information on materials

EN 12811-3:2002, Temporary works equipment — Part 3: Load Testing

3 Terms and definitions

For the purposes of this European Standard, the terms and definitions given in EN 12810-1 and EN 12811-1 apply

4 Structural design

4.1 General

Structural design of the system configurations of the standard set of each prefabricated scaffold system shall be

carried out in accordance with the requirements of EN 12811-1, prEN 12811-2 and EN 12811-3 and EN 12810-1

and this European Standard

The structural design shall follow one of the paths in Table 1, see also Figure 1

1 Tests for configurations, connection devices and components

2 / 3 Calculation for each system configuration of the standard set

Determination of αcr

2

Continuation of path 2 only ifαcr ≥2;

if αcr < 2 change to path 1Analysis of the structure to determine the distribution of forces and moments using3a

Second order theory First order theory with amplification factors on the basis of

αcr3

3b Analysis of the individual components and connection to verify that the resistance is adequate

One test on a representative section of a system configuration

For the verification of significant loaddisplacement behaviour

Type 2For the verification of αcr

αcr is the lowest elastic buckling load factor to be applied to the design loads

Path 1 is the preferred path Path 2 may only be used for frame systems and only when the quotient αcr is not less

than 2

Stages 2 and 3 shall be carried out for each system configuration of the standard set in accordance with the

requirements set out in clause 8 of EN 12810-1:2003

Stage 3b shall include the analysis of all components and the connection devices considering their most

unfavourable loading situation If member imperfections have not been included in the analysis model, component

stability shall be checked separately

For the determination of internal forces and moments, elastic methods shall be used The non-linear structural

characteristics of modular nodes and horizontal planes, determined in accordance with the requirements of

EN 12811-3, shall be used in the analysis

The load bearing capacity of a system configuration is reached if

 either for one cross section, the resistance in accordance to EN 12811-1 is reached;

 or the resistance of a component, of a connection device or of a spring is reached

NOTE Such resistances are evaluated from test results

In path 1, the equilibrium of the displaced system shall be taken into account directly by the use of a second order

analysis In path 2, the equilibrium of the displaced system shall be taken into account indirectly by the use of a first

order analysis with amplification factors

A test at stage 4 shall be carried out on a representative section of a system configuration

4.2 Models for structural analysis

The arrangement of horizontal and vertical components, the disposition and frequency of bracing components, and

the position and frequency of ties shall be in accordance with the product manual

Figure 2 shows a typical system configuration This spatial system shall be considered either by carrying out a

three-dimensional analysis or by splitting it into separate planar systems, to be checked separately, provided that

the interaction between them is adequately taken into account

Figure 2 also shows examples of vertical plane substitution systems normal to the facade Figures 3, 4 and 5 show

an example of a vertical plane substitution system parallel to the façade

In the treatment of any substitution system the boundary conditions shall be chosen so that the response of the

substitution system is representative of the behaviour of the whole structure

The restraining, destabilising and loading effects of components, not lying in the plane under investigation, shall be

taken into account In particular, although the system lies in one plane, out of plane buckling shall be examined

The relevant load deformation behaviour of the configurations and the connection devices, for instance between

transoms, ledgers, diagonals and standards shall be incorporated in the analysis model

Linearisation by chords in accordance with 10.10 of EN 12811-3:2002 and assumptions on the conservative side

are permitted

Figure 1 — Flow diagram of the stages of the structural design

EN 12810-2:2003 (E)

Figure 2 — Examples of plane vertical substitution systems normal to the façade for the anchorage pattern

shown

Figure 3 - Development of a substitution system parallel to the façade (Key see Figure 5)

Figure 4 - Detail of Figure 3 (Key see Figure 5)

EN 12810-2:2003 (E)

Key

Fi,; Fa maximum forces from the scaffold above on the outer and inner standards

ns number of standards to be stabilised in the example

nt number of tie members in the group of standards to be stabilised

Is moment of inertia of a standard

ch horizontal stiffness parallel to the façade of one bay

ct stiffness of a tie member parallel to the façade

Key

4 inner plane: ns x ls, ns x As

5 outer plane: ns x ls, ns x As

6 spring with the stiffness (ns – 1) x cb

7 spring with the stiffness nt x ct

Figure 5 — Example of a vertical substitution system parallel to the façade for the configuration in Figure 2

4.3 Tests on configurations and connection devices

4.3.1 Tests for stiffness and resistance

The required tests shall be carried out and the results shall be evaluated in accordance with EN 12811-3 At leastfive tests shall be carried out for each parameter

Annex A gives examples of typical tests for configurations and connection devices

Where a connection device or configuration is subjected to actions in more than one direction, then any significantinteraction between these actions shall be taken into account

NOTE 1 Typically there may be interaction between normal force and bending moment in a connection device, but it ispossible for the interaction to occur in more than two directions

As a minimum requirement the design resistance Rd under each of the relevant actions shall be separatelydetermined in accordance with the requirements of EN 12811-3 and a linear interaction equation used to check theconnection devices or configurations For two actions the linear interaction formula is given in expression (1)

0

2

2 1

d

d S d

R

F R

F

(1)

in which

FSd1 and FSd2 are the design values resulting from the actions and

Rd and Rd are the design values of the resistances

This is usually a conservative approach The straight dotted line shown in Figure 6 represents this equation

When tests are made under combined actions then it may be possible to show that the resulting failure values (testresults) lie above the straight line In this case a suitable approximation may be used to represent the interactioncurve As an example, in Figure 6 the heavy curve shown is given by the expression (2)

0

2 2 2

1

d

Sd d

F

(2)

The experimentally derived characteristic values shall lie on or outside the interaction curve

NOTE 2 For some modular connection devices, depending on the details of the construction, axial force in the standard, aswell as shear or axial force in the transom, may influence the design strength of the connection device in bending

4.3.2 Vibration test

In the case of connection devices whose integrity depends upon the use of a wedge or another loose element thatcan fall out of proper engagement, vibration loading tests shall be made in accordance with 7.4 of EN 12811-3:2002 The requirements of 8.6 of EN 12810-1:2003 shall be met

EN 12810-2:2003 (E)

Key

•

Figure 6 — Interaction relationship

4.4 Tests on a representative section of a system configuration

4.4.2 Type 1 test for verification of significant load displacement behaviour

As an example, Figure 7 shows a test configuration appropriate for a type 1 test of the scaffold system where adiagonal supports three bays and where the anchorage pattern corresponds to the pattern in Figure 2

Regarding the modelling of the boundary conditions for the base jacks and the application of the vertical loads,some freedom is available as long as the comparison calculation models the same boundary conditions

Figure 7 — Example of a configuration for a type 1 test

The test configuration shall be loaded with:

a) A vertical load on each standard The value for each internal standard shall be Fv and for each standard, atleast Fv/2;

b) At least one horizontal load, Fn, normal to the facade at an unanchored node point;

c) Two horizontal loads, each

F

The value of each horizontal force, FH, is given by equation (3):

Where

Fd is the design wind force of a single node point, see 8.3 of EN 12811-1:2003;

np is the total number of node points which lie in the same line on the horizontal plane under consideration inthe direction of the wind

The horizontal loads shall be applied first Subsequently, the vertical loads shall be applied and increased untilfailure occurs During this process the structure shall be unloaded at least once in order to bed the components in.The displacements of the node points shall be measured where the horizontal loads are applied The vertical loadsand the displacements shall be recorded in a sufficient number of steps during loading and unloading to define thedeformation curves

A static analysis shall be carried out for the test configuration over the range of the applied loading and thedisplacements shall be determined

The load displacement curves determined in the tests shall be compared with those determined by calculation The

EN 12810-2:2003 (E)

4.4.3.1 Test assembly

The test assembly shall comprise a representative section of a system configuration from the bottom of a scaffold

If the scaffold system includes adjustable base plates they shall be fully extended The length and the height of thetest assembly shall reflect the normal anchorage pattern of the system

In general the test assembly shall include all connection devices and configurations for which detail tests werecarried out to determine parameters for the static calculation such as stiffness and resistance

The number of bays shall be equal to a multiple of the number of bays over which the vertical bracing repeats

As examples, Figure 8 and Figure 9 show test assembly configurations appropriate for a type 2 test of scaffoldsystems where a diagonal supports three or four bays

The boundary conditions for the adjustable base plates and the application of the vertical loads shall be the same

in the experimental and the theoretical models

4.4.3.2 Test procedure

In each plane parallel to the façade the vertical load applied to the internal standards shall be twice that applied tothe outside standards

The following load and loading procedure on the test assembly shall be complied with :

a) Vertical loads shall be applied at the topmost node points

c) The vertical loads and at least one significant displacement normal and one significant displacement parallel tothe façade shall be recorded in a sufficient number of steps during loading to define the deformation curve.

4.4.3.3 Validation of αcr

The elastic buckling loading factor αc,t determined from the test shall be compared with the elastic buckling loadingfactor αcr,c determined by a static analysis The condition αcr,c < αcr,t shall be fulfilled