SIST EN 12812:2004

SLOVENSKI STANDARD
SIST EN 12812:2004
01-oktober-2004
Nosilni odri – Zahtevane lastnosti in projektiranje
Falsework - Performance requirements and general design
Traggerüste - Anforderungen, Bemessung und Entwurf
Etaiements - Exigences de performance et méthodes de conception et calculs
Ta slovenski standard je istoveten z: EN 12812:2004
ICS:
91.220 Gradbena oprema Construction equipment
SIST EN 12812:2004 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 12812:2004

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SIST EN 12812:2004
EUROPEAN STANDARD
EN 12812
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2004
ICS 91.220
English version
Falsework - Performance requirements and general design
Etaiements - Exigences de performance et méthodes de Traggerüste - Anforderungen, Bemessung und Entwurf
conception et calculs
This European Standard was approved by CEN on 10 December 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 Central Secretariat 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 Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of 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 United Kingdom.
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EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2004 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 12812:2004: E
worldwide for CEN national Members.

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SIST EN 12812:2004
EN 12812:2004 (E)
Contents Page
1 Scope. 5
2 Normative references. 5
3 Terms and definitions. 6
4 Design classes. 7
4.1 General. 7
4.2 Design class A. 7
4.3 Design class B. 8
5 Materials. 8
5.1 General. 8
5.2 Basic requirements for materials . 8
5.3 Weldability. 8
6 Brief. 9
7 Design requirements. 9
7.1 General. 9
7.2 Thickness of material . 9
7.3 Connections. 10
7.4 Flexibility of prefabricated support towers . 10
7.5 Foundation. 11
7.6 Towers providing support. 13
8 Actions. 13
8.1 General. 13
8.2 Direct actions. 14
8.3 Indirect actions "Q ". 17
7
8.4 Load combinations. 18
9 Structural design. 19
9.1 Technical documentation. 19
9.2 Structural design. 20
9.3 Imperfections and boundary conditions . 24
9.4 Calculation of internal forces . 30
9.5 Characteristic values of resistance and friction values. 38
Annex A (informative) Relation with site activities . 40

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SIST EN 12812:2004
EN 12812:2004 (E)
Foreword
This document (EN 12812:2004) 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 December 2004, and conflicting national standards
shall be withdrawn at the latest by December 2004.
No other international organisation has been involved.
This European Standard is one of a package of standards that includes also EN 12810-1,EN 12810-2,
EN 12811-1, EN 12811-2, EN 12811-3, EN 12813.

This European Standard does not replace any other European Standard.
This European Standard was prepared as part of a group, see above. It gives some information about
products covered by:
 scaffold tube in accordance with EN 39;
 scaffold couplers in accordance with EN 74;
 adjustable telescopic props in accordance with EN 1065.
The standard is not mandated. However cognisance of two European Directives should be taken.
These are:
Council Directives 89/391/EEC and 92/57/EEC.
The Annexes A and B are informative.
This document includes a bibliography
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 United Kingdom.




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SIST EN 12812:2004
EN 12812:2004 (E)
Introduction
Most falsework is used:
 to carry the loads due to freshly poured concrete for structures until these structures have
reached a sufficient load bearing capacity;
 to absorb the loads from structural members, plant and equipment which arise during the erection,
maintenance, alteration or removal of buildings or other structures;
 additionally, to provide support for the temporary storage of building materials, structural
members and equipment.
This European Standard gives performance requirements for those who specify and use falsework
and gives methods to design falsework to meet those requirements. Clause 9 provides design
methods. It legitimizes simplified design methods for falsework made of tube and couplers already
successfully in use. The information on structural design is supplementary to the relevant structural
Eurocodes.
The standard describes different design classes. This allows the designer to choose between more or
less complex design methods, while achieving the same level of structural safety.
Because European Standards for materials do not exist to support the standard fully, it has been
prepared permitting equivalent national standards to be used. Publication of a European Standard
always results in the withdrawal of equivalent national standards.
Provision for specific personal safety matters is dealt with in EN 12811-1:2003 and other documents.
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SIST EN 12812:2004
EN 12812:2004 (E)
1 Scope
This European Standard specifies performance requirements and limit state design methods for two
design classes of falsework.
It sets out the rules that a designer has to take into account to produce a safe falsework structure.
It also provides information for the person who requires falsework to support a "permanent structure"
and who needs to commission its design or supply.
This European Standard also gives information on foundations.
This European Standard does not specify requirements for formwork, although formwork may be a
part of the falsework construction. Nor does it provide information on access and working scaffolds,
which is given in EN 12811-1:2003.
This European Standard does not provide information about site activities. It does not provide
information about the use of some standardized products, including beams conforming to EN 13377
and props conforming to EN 1065.
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 74, Couplers, loose spigots and base-plates for use in working scaffolds and falsework made of
steel tubes — Requirements and test procedures.
EN 1065:1998, Adjustable telescopic steel props — Product specifications, design and assessment
by calculation and tests.
EN 1990, Eurocode — Basis of structural design.
ENV 1991 (all parts including EN 1991-1-1, EN 1991-1-2, prEN 1991-1-3 and prEN 1991-2),
Eurocode 1 — Basis of design and actions on structures.
ENV 1992 (all parts), Eurocode 2 — Design of concrete structures.
ENV 1993 (all parts), Eurocode 3 — Design of steel structures.
ENV 1994 (all parts), Eurocode 4 — Design of composite steel and concrete structures.
ENV 1995 (all parts), Eurocode 5 — Design of timber structures.
ENV 1996 (all parts), Eurocode 6 — Design of masonry structures.
ENV 1997 (all parts), Eurocode 7 — Geotechnical design.
ENV 1998 (all parts), Eurocode 8 — Design provisions for earthquake resistance of structures.
ENV 1999 (all parts), Eurocode 9 — Design of aluminium structures.
rEN 12811-1:2003, Scaffolds — Performance requirements and general design.
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SIST EN 12812:2004
EN 12812:2004 (E)
EN 12811-3:2002, Temporary works equipment — Part 3: Load testing.
EN 12813, Load bearing towers of prefabricated elements — Methods of particular design and
assessment.
EN 12810-1:2003, Facade scaffolds made of prefabricated components — Part 1: Product
specification.
DIN 18218, Pressure of fresh concrete on vertical formwork.
C E Clear and T A Harrison. Concrete pressure on formwork. CIRIA Report No. 108.London
Construction Industry Resarch and Information Association
Manual de Technologie: Coffrage; CIB-FIB-CEB 27-98-83.
3 Terms and definitions
For the purposes of this European Standard, the terms and definitions in ENV 1993-1 and the
following apply.
3.1
brace
component connecting two points of a structure to help stiffen it
3.2
design class
class that defines the extent of design for falsework
3.3
falsework
temporary support for a part of a structure while it is not self-supporting and for associated service
loads
3.4
formwork
part of temporary works used to give the required shape and support to in-situ concrete
3.5
foundation
sub-structure needed to transmit loads into the ground
3.6
kentledge
material placed on a structure to provide stability by the action of its dead weight
3.7 imperfections

3.7.1
imperfection
divergence from the theoretical when erected ready for use
3.7.2
bow imperfection
initial out of true before loading
NOTE A bow imperfection can occur both in an individual member and in the complete tower or modular
beam assembly. It arises because the member is not straight, is manufactured not straight or members are
assembled out of alignment.
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SIST EN 12812:2004
EN 12812:2004 (E)
3.7.3
sway imperfection
out of true before loading in an erected structure, measured as an angle
NOTE This is the value for design purposes and may be more than the erection tolerance.
3.8
modular truss beam
longitudinally extensible beam made from a series of units capable of assembly to create various
lengths
3.9
modular column
compression member assembled from components of various lengths, with adjustment means at one
or both ends
3.10
node
theoretical intersection point of members
3.11
sway
angular movement of a column or other structure caused by the application of load measured as an
angle
4 Design classes
4.1 General
The design shall be in accordance with one of three classes: A, B1 and B2.
NOTE The classes are identified as follows:
a) Class A: Falsework where the structural integrity is derived from a knowledge of the structural performance of
components of the structure, such as adjustable props or formwork equipment. The structural performance of
these components is individually rated. Capability to withstand vertical and horizontal loads is determined from
experience and established good practice.
b) Class B: Falsework where a complete design is undertaken. This class has two sub-classes,see 4.3.
4.2 Design class A
Class A covers falsework for simple constructions such as in situ slabs and beams.
Class A shall only be adopted where:
2
a) slabs have a cross-sectional area not exceeding 0,3 m per metre width of slab;
2
b) beams have a cross-sectional area not exceeding 0,5 m
c) the clear span of beams and slabs does not exceed 6,0 m;
d) the height to the underside of the permanent structure does not exceed 3,5 m.
The design shall be in accordance with Clauses 5 and 7.
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SIST EN 12812:2004
EN 12812:2004 (E)
4.3 Design class B
4.3.1 Class B1
The design shall be in accordance with the relevant European structural design standards in the
Eurocode series (EN 1990, ENV 1991 to ENV 1999) and additionally with 9.1.1, 9.1.2.1, 9.1.3, 9.3.3
and 9.4.1 of the present standard.

NOTE It is assumed that the erection will be carried out to the level of workmanship appropriate for
permanent construction.
4.3.2 Class B2
The design shall be in accordance with Clauses 5, 6, 7, 8 and 9, with the exception of 9.1.2.1, 9.3.3,
9.4.1, and with the relevant European structural design standards in the Eurocode series (EN 1990,
ENV 1990 to ENV 1999). Where there is a conflict, the provisions of the present standard shall take
precedence.
NOTE Attention is drawn to the simplified methods given in 9.3 and 9.4 and to the requirements for
drawings and other documentation given in 9.1.2.
5 Materials
5.1 General
Only materials that have established properties and that are known to be suitable for the intended use
shall be used.
5.2 Basic requirements for materials
5.2.1 If a European, international or national standard exists in which there is design data for a
particular material or item of equipment, the material or equipment shall conform to the requirements
of that standard. The requirements of European Standards shall take precedence.
NOTE See the relevant national Foreword.
5.2.2 Materials and equipment shall have had their relevant properties established by testing
(see 9.5.2) where these cannot be obtained from the standards referred in 5.2.1.
5.2.3 Rimming steel shall not be used.
5.3 Weldability
The steel used shall be weldable, unless structural members and components are not intended to be
welded.
For example, castings may be used at node points.
NOTE Different steels require different welding techniques. In general, welding of unidentified steels should
not be undertaken for structural work. Steelwork that has been repaired by welding may be used provided that
the remedial work has been carried out in accordance with the appropriate standard. The type and grade of steel
should first be identified.
The design shall not require any welding of aluminium to be undertaken on site.
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SIST EN 12812:2004
EN 12812:2004 (E)
6 Brief
The design shall be based on a brief containing all necessary data including information on erection,
use, dismantling and loading.
NOTE 1 Concrete is a typical example of loading.
NOTE 2 Adequate information about site conditions should be obtained and included in the brief. Particular
points are:
 layout with levels, including adjacent structures;
 general appreciation of the parameters relating to wind load calculations for the local conditions;
 positions of services such as water pipes or electricity cables;
 requirements for access and safe working space;
 information about the ground conditions.
7 Design requirements
7.1 General
The structure shall be designed such that all the loads acting on it are carried into the subsoil or into a
load-bearing substructure.
The available skill in erection and the ambient circumstances should be taken into account in the
design.
Provision shall be made for the means of access for erection, use and dismantling. Reference should
be made to EN 12811-1.
The design should be based on concepts and details the realization of which is practicable and which
are straightforward to check on site.
7.2 Thickness of material
7.2.1 Thickness of steel and aluminium components
The nominal wall thickness shall be not less than 2 mm.
7.2.2 Steel scaffold tubes
Loose steel tubes to which it is possible to attach couplers conforming to EN 74 shall be in
accordance with EN 12811-1:2003, 4.2.1.2.
Tubing for incorporation in prefabricated components to which it is possible to attach couplers
conforming to EN 74 shall be in accordance with EN 12811-1:2003, 4.2.2.1 and with
EN 12810-1:2003, Table 2.
7.2.3 Aluminium scaffold tubes
Loose aluminium tubes to which it is possible to attach couplers conforming to EN 74 shall be in
accordance with EN 12811-1:2003, 4.2.2
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SIST EN 12812:2004
EN 12812:2004 (E)
7.3 Connections
7.3.1 Connection devices
Connections shall be designed such that they cannot be disconnected unintentionally when in use.
Vertical spigot connections between hollow sections in compression without additional means of
fixing shall be deemed to be secure against unintentional disconnection if the overlapping length is
not less than 150 mm.
7.3.2 Overlap of loose base jacks and head jacks with tube
The overlap length of the jack in the tube, l (see 9.3.2), shall be either 25 % of the jack length, l or
0 1
150 mm, whichever is the greater.
7.4 Flexibility of prefabricated support towers
*
A prefabricated support tower shall have a design capacity, R , of 90 % of its normal design load
d
bearing capacity, R , when a differential settlement, δ , has been imposed or when a thermal
d s
movement of the supported construction has caused a horizontal movement, δ (see Figure 1), which
t
the tower shall accommodate.
The value of the settlement, δ , shall be the lesser of 5 mm and that calculated from equation (1); the
s
maximum value of the thermal movement shall be calculated from equation (2) taking the lesser of the
two values of δ from the previous examination.
s
−3
δ = 2,5×10 ×l (1)
s
δ = δ × h/l (2)
t s
where:
R is the normal design value of the load bearing capacity;
d
R * is the design value of the load bearing capacity after differential settlement or thermal
d
movement has occurred;
h is the overall height of the tower,
l is the horizontal base of the support structure,
δ is the differential settlement,
s
δ is the horizontal movement caused by temperature.
t
NOTE This requirement for flexibility is intended to enable towers to be used in typical site conditions.

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SIST EN 12812:2004
EN 12812:2004 (E)



a) Theoretical system b) Differential settlement c) Thermal movement
NOTE See 7.4 for symbol definitions.
Figure 1 — Relative deflections due to differential settlement or restraint
7.5 Foundation
7.5.1 Basic foundation requirements
The structure shall be supported directly from one or more of the following:
 a sub-structure provided for the purpose;
 the surface of the existing ground, e.g. rock;
 a partly excavated and prepared surface, e.g. in soil;
 a permanent structure which already exists.
Except where the conditions described in 7.5.2 apply, design shall follow normal rules taking account
of the expected life of the structure.
7.5.2 Support without any embedment in the ground
For a spread foundation, topsoil shall always be removed.
The foundation shall not be placed directly on such a levelled surface without embedment unless all
of the following conditions are met:
 the foundation is made secure against degradation by surface water and ground water during the
life of the falsework;
NOTE 1 This may be done by providing drainage or protecting the surface with a concrete skin.
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SIST EN 12812:2004
EN 12812:2004 (E)
 it is known that frost is not likely to occur which might affect permeable ground during the life of
the falsework;
 either the support of the foundation is within 8 % of horizontal or, if the average slope exceeds
8 %, there is provision to transmit any component of force down the slope either to a thrust block
or by other means, dissipating the force to the ground;
 in the case of cohesive soils, and where the distance to the edge is large, provision is made for
drainage below the foundation slab;
 in the case of non-cohesive soils, the ground water level is not likely to rise to within 1 m of the
bottom of the structure;
NOTE 2 The object of this limitation is to keep settlement at a sufficiently low value.
 lateral shear capacity is verified.
7.5.3 Support from an existing permanent structure
The ability of the permanent structure to support the applied loads shall be verified.
7.5.4 Stacked members
Where a part of the structure consists of horizontal rectangular timber members or similar placed one
on top of another (see Figure 2), the lateral stability may require verification. This is always likely to
be the case when the members above are not laterally restrained near their supports.
Verification shall be carried out if any of the following occur:
 two members are put one above the other with their long sides parallel [see Figure 2b)];
 the base width, b , is less than twice the height, h ;
i i
 the total height, h , exceeds 400 mm.
i
Values of h and b shall be taken such that the worst conditions are considered.
i i
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SIST EN 12812:2004
EN 12812:2004 (E)

a) cross grillage

b) stacked members
c) parallel members one above the other
Figure 2 — Examples of arrangement of stacked members
7.6 Towers providing support
8 The cross-sectional shape of a support structure shall be maintained at the
top and bottom, e.g. by bracing or stiffened planes.Actions
8.1 General
Standard actions, direct and indirect (Q to Q ), are described in the following subclauses. Where
1 7
appropriate for a specific project, account shall be taken of other loading conditions, e.g. the action
due to mechanical plant moving.
NOTE 1 ENV 1991-2 provides additional information about actions.
NOTE 2 The main load combinations are given in 8.4.
NOTE 3 These values should be taken as characteristic values for actions.
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EN 12812:2004 (E)
8.2 Direct actions
8.2.1 Permanent actions "Q "
1
NOTE While these permanent loads are anticipated to last the duration of the structure, as this is short, they
are considered as variable for calculation purposes.
8.2.1.1 Self-weight
The self-weight shall be taken into account.
NOTE Self-weight includes:
a) the falsework structure;
b) the formwork where applicable;
c) kentledge.
8.2.1.2 Soil
Lateral ground pressure shall be calculated in accordance with ENV 1997.
8.2.2 Variable imposed actions
8.2.2.1 Variable persistent vertical imposed actions "Q "
2
8.2.2.1.1 Supported construction
Where other information is not available, the load from the permanent structure or other items to be
supported shall be calculated from the volume and density of the material. In the case of concrete,
this shall include the reinforcement.
3
For normal fresh concrete, the density shall be taken as 2 500 kg/m .
2
NOTE For design purposes, this may be taken as equivalent to 25 kN/m per metre depth.
8.2.2.1.2 Storage areas
For design purposes, pressures due to material shall be deemed to be either the actual storage
2
pressure or 1,5 kN/m , whichever is the greater. This provision shall extend either over the whole of
the working area, or to a specifically designated area marked on the site.
8.2.2.1.3 Construction operations loading – operatives
2
A minimum live load allowance of 0,75 kN/m shall be taken into account for all access and working
areas supported by falsework. For example, this shall be applied to the platforms on a travelling
cantilever bridge falsework unit while being moved forward.
NOTE A higher loading can be appropriate depending on the work to be carried out. Reference should be
made to EN 12811-1.
8.2.2.1.4 Snow and ice
2
The loading from snow and ice shall be taken into account when it is expected to exceed 0,75 kN/m .
NOTE In conditions when there is high humidity and rain or snow and the structure is below freezing point,
3
icing can occur. In such a case an allowance should be made. Maximum ice density is 920 kg/m .
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For the purposes of calculating the horizontal force from floating ice, it shall be deemed to be debris
(see 8.2.5.2).
8.2.2.2 Variable persistent horizontal imposed actions "Q "
3
A horizontal load equal to 1 % of the vertical load shall be taken into account applied externally at the
point of application of the vertical load (Q and Q ).
1 2
This external load shall be deemed to be taken through the structure to a point of adequate external
restraint, generally to the underside of the falsework foundations.
NOTE This force is considered to be caused by minor forces not otherwise identified, such as lateral forces
caused by concrete pumping.
8.2.3 Variable transient imposed actions, "Q "
4
8.2.3.1 In-situ concrete loading allowance
Where in-situ concrete is to be placed, a live load allowance additional to that specified in 8.2.2.1.3
shall be adopted, making the total additional load equal to 10 % of the self-weight of the concrete. In
2 2
no case shall the additional allowance be less than 0,75 kN/m nor need it be more than 1,75 kN/m .
This additional load shall be deemed to act on a square area of plan size
...