SIST EN 12812:2008

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Nosilni odri - Zahtevane lastnosti in projektiranjeTraggerüste - Anforderungen, Entwurf und BemessungEtaiements - Exigences de performance et méthodes de conception et calculsFalsework - Performance requirements and general design91.220Gradbena opremaConstruction equipmentICS:Ta slovenski standard je istoveten z:EN 12812:2008SIST EN 12812:2008en,fr01-oktober-2008SIST EN 12812:2008SLOVENSKI
STANDARDSIST EN 12812:20041DGRPHãþD



SIST EN 12812:2008



EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 12812July 2008ICS 91.220Supersedes EN 12812:2004
English VersionFalsework - Performance requirements and general designEtaiements - Exigences de performance et méthodes deconception et calculsTraggerüste - Anforderungen, Bemessung und EntwurfThis European Standard was approved by CEN on 7 June 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN 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 translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2008 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 12812:2008: ESIST EN 12812:2008



EN 12812:2008 (E) 2 Contents Page Foreword.3 Introduction.4 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.7 5 Materials.8 5.1 General.8 5.2 Basic requirements for materials.8 5.3 Weldability.8 6 Brief.8 7 Design requirements.8 7.1 General.8 7.2 Thickness of material.9 7.3 Connections.9 7.4 Flexibility of prefabricated support towers.9 7.5 Foundation.10 7.6 Towers providing support.12 8 Actions.13 8.1 General.13 8.2 Direct actions.13 8.3 Indirect actions.17 8.4 Other actions “Q9”.17 8.5 Load combinations.17 9 Structural design for classes B1 and B2.18 9.1 Technical documentation.18 9.2 Structural design.20 9.3 Imperfections and boundary conditions.23 9.4 Calculation of internal forces.30 9.5 Characteristic values of resistance and friction values.37 Annex A (informative)
Relation with site activities.40 Annex B (informative).41 Bibliography.42
SIST EN 12812:2008



EN 12812:2008 (E) 3 Foreword This document (EN 12812:2008) 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 January 2009, and conflicting national standards shall be withdrawn at the latest by January 2009. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 12812:2004. 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.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. SIST EN 12812:2008



EN 12812:2008 (E) 4
Introduction Most falsework is used:  to carry the loads due to freshly poured concrete for permanent 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 specifying and using falsework and gives methods to design falsework to meet those requirements. Clause 9 provides design methods. It also gives simplified design methods for falsework made of tubes and fittings. 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. Provision for specific safety matters is dealt with in EN 12811-1 and other documents. SIST EN 12812:2008



EN 12812:2008 (E) 5 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 have to be taken into account to produce a safe falsework structure. It also provides information for falsework which is required to support a "permanent structure", or where the design or supply of falsework has to be commissioned. 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. This European Standard does not provide information about site activities. It does not provide information about the use of some standardized products, including timber formwork beams conforming to EN 13377 and props conforming to EN 1065. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
EN 74-1, Couplers, spigot pins and baseplates for use in falsework and scaffolds — Part 1: Couplers for tubes — Requirements and test procedures prEN 74-2, Couplers, spigot pins and baseplates for use in falsework and scaffolds — Part 2: Special couplers — Requirements and test procedures EN 74-3, Couplers, spigot pins and baseplates for use in falsework and scaffolds — Part 3: Plain base plates and spigot pins — Requirements and test procedures EN 1065:1998, Adjustable telescopic steel props — Product specifications, design and assessment by calculation and tests EN 1090-2, Execution of steel structures and aluminium structures - Part 2: Technical requirements for steel structures EN 1090-3, Execution of steel structures and aluminium structures - Part 3: Technical requirements for aluminium structures EN 1990, Eurocode — Basis of structural design EN 1991 (all parts), Eurocode 1 — Actions on structures EN 1993-1-1:2005, Eurocode 3: Design of steel structures - Part 1-1: General rules and rules for buildings EN 1997 (all parts), Eurocode 7 — Geotechnical design EN 1998 (all parts), Eurocode 8 — Design of structures for earthquake resistance EN 1999 (all parts), Eurocode 9 — Design of aluminium structures SIST EN 12812:2008



EN 12812:2008 (E) 6 EN 12810-1:2003, Facade scaffolds made of prefabricated components — Part 1: Product specifications EN 12811-1:2003, Temporary works equipment — Part 1: Scaffolds — Performance requirements and general design EN 12811-3, Temporary works equipment — Part 3: Load testing EN 12813, Temporary works equipment - Load bearing towers of prefabricated components - Particular methods of structural design EN 13377, Prefabricated timber formwork beams — Requirements, classification and assessment 3 Terms and definitions For the purposes of this document, the terms and definitions in EN 1993-1-1:2005 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 initial out of straightness (bow imperfection) or out of verticality (sway imperfection) of a structural component or of the structure used for calculations
NOTE 1 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. NOTE 2 These are the values for design purposes and may be more than the erection tolerance. 3.8 node theoretical intersection point of members SIST EN 12812:2008



EN 12812:2008 (E) 7 3.9 sway angular deflection of a column or other structure caused by the application of load
4 Design classes 4.1 General The design shall be in accordance with one of the classes: A or B. Class B has two subclasses, B1 and B2, see 4.3 where the designer has to decide which subclass shall be applied. 4.2 Design class A NOTE A Class A falsework is one which follows established good practice which may be deemed to satisfy the design requirements. Class A covers falsework for simple constructions such as in situ slabs and beams. Class A shall only be adopted where: a) slabs have a cross-sectional area not exceeding 0,3 m2 per metre width of slab; b) beams have a cross-sectional area not exceeding 0,5 m2; 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 for class A falsework shall be in accordance with the descriptive requirements in Clauses 5 and 7. 4.3 Design class B Class B falsework is one for which a complete structural design is undertaken. Class B falsework is required to be designed in accordance with the relevant Eurocodes. There are separate additional provisions in this code for Classes B1 and B2 that are detailed below. Class B2 uses a simpler design method than Class B1 to achieve the same level of safety. 4.3.1 Class B1 The design shall be in accordance with the relevant Eurocodes (EN 1990, EN 1991 to EN 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, see EN 1090-2 and EN 1090-3 for metal structures. 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 Eurocodes (EN 1991, EN 1990 to EN 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. SIST EN 12812:2008



EN 12812:2008 (E) 8 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 Materials shall comply with European product Standards; where they do not exist national standards shall be used. 5.2.2
Where the relevant properties of materials and equipment cannot be obtained from the standards referred to in 5.2.1, their properties shall be established by testing (see 9.5.2).
5.2.3 Steel of deoxidation type FU (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. Welding shall be carried out in accordance with the requirements of EN 1090-2 and EN 1090-3. The design shall not require any welding of aluminium to be undertaken on site. 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 sub-structure. The available skill in erection and the ambient circumstances should be taken into account in the design. SIST EN 12812:2008



EN 12812:2008 (E) 9 Provision shall be made for the means of access for erection, use and dismantling. Reference shall be made to EN 12811-1. The design should be based on concepts and details which ensure a practicable realization and which are straightforward for on site checks. 7.2 Thickness of material 7.2.1 Thickness of steel and aluminium components The nominal 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 74-1, prEN 74-2 and baseplates and spigots conforming to EN 74-3 shall be in accordance with EN 12811-1:2003, 4.2.1.2. Tubes for incorporation in prefabricated components to which it is possible to attach couplers conforming to EN 74-1, prEN 74-2 and baseplates and spigots conforming to EN 74-3 shall be in accordance with EN 12811-1:2003, 4.2.1.3 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 74-1, prEN 74-2 and baseplates and spigots conforming to EN 74-3 shall be in accordance with EN 12811-1:2003, 4.2.2.1. 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, l0 (see 9.3.2), shall be either 25 % of the jack length, l1, or 150 mm, whichever is the greater. 7.4 Flexibility of prefabricated support towers A prefabricated support tower shall have a design capacity, Rd*, of 90 % of its normal design load bearing capacity, Rd, when a differential settlement, δs, has been imposed or when a thermal movement of the supported construction has caused a horizontal movement, δt (see Figure 1), which the tower shall accommodate.
The value of the settlement, δs, shall be the lesser of 5 mm and that calculated from Equation (1); the maximum value of the thermal movement shall be calculated from Equation (2) taking the lesser of the two values of δs from the previous examination. l/××=−3s105,2≤ 5 mm (1) SIST EN 12812:2008



EN 12812:2008 (E) 10 δt = δs × h/l
(2) where Rd is the normal design value of the load bearing capacity; Rd* is the design value of the load bearing capacity after differential settlement or thermal movement has occurred; h is the overall height of the tower in millimetres; l is the horizontal base of the support tower in millimetres;
δs is the differential settlement; δt is the horizontal movement caused by temperature.
a) Theoretical system b) Differential settlement c) Thermal movement NOTE See 7.4 for symbol definitions. Figure 1 — Relative deformations due to differential settlement or thermal movement 7.5 Foundation 7.5.1 Basic requirements for foundations The structure shall be supported directly from one or more of the following:  a sub-structure provided for the purpose; SIST EN 12812:2008



EN 12812:2008 (E) 11  the surface of the existing ground, e.g. rock;  a partly excavated and prepared surface, e.g. in soil;  a structure which already exists;  foundation according to 7.5.2. Except where the conditions described in 7.5.2 apply, design shall follow the Eurocodes 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.  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 to a sufficiently low value.  lateral shear capacity is verified. 7.5.3 Support from an existing permanent structure The resistance of the permanent structure to the applied loads from the falsework shall be verified. 7.5.4 Stacked squared members Stacked members consisting of rectangular timber elements or comparable components may be used: –
for the support construction for load bearing towers; – for the height adjustment of the base-construction in combination with the foundation.
In each case, stacked members shall be placed crosswise, and the base area shall be enlarged with every layer from top to bottom. The support construction for load bearing towers shall cover the whole cross-section of the tower (Figure 2a). SIST EN 12812:2008



EN 12812:2008 (E) 12 The top-end of the stacked members shall be designed as a horizontal restrained bearing point or, by means of horizontal bracings, the bearing point is to be stabilized in any horizontal direction. The stacked member is deemed to be a horizontal restrained bearing point, if the following condition is met: 6bFhFeVH≤⋅=
h ≤ 40cm (3) For bandhFFVH,,see Figure 2.b).
a) support of a load bearing tower by stacked members
Key 1 lower edge of base plate
b) stacked member for height adjustment
Figure 2 — Examples of arrangement of stacked members 7.6 Towers providing support
The cross-sectional shape of a support tower shall be maintained e.g. by bracing or stiffened planes; at the top and bottom, the formwork and the foundation may substitute for the bracing if appropriately connected. SIST EN 12812:2008



EN 12812:2008 (E) 13 8 Actions 8.1 General Typical actions on falsework, direct and indirect (Q1 to Q8), are described in the following subclauses. Where appropriate for a specific project, account shall be taken of other loading conditions (Q9), e.g. the action due to mechanical plant moving. The values Q1 to Q9 are characteristic values of actions. 8.2 Direct actions 8.2.1 Permanent actions "Q1" 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 EN 1997. 8.2.2 Variable imposed actions 8.2.2.1 Variable persistent vertical imposed actions "Q2" 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. For normal reinforced fresh concrete, the density shall be taken as 2 500 kg/m3. NOTE For design purposes, this may be taken as equivalent to 25 kN/m2 per metre depth. 8.2.2.1.2 Storage areas For design purposes, uniformly distributed loads due to material shall be deemed to be either the actual storage pressure or 1,5 kN/m2, 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 falsework. 8.2.2.1.3 Construction operations loading – operatives A minimum live load allowance of 0,75 kN/m2 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. SIST EN 12812:2008



EN 12812:2008 (E) 14 8.2.2.1.4 Snow and ice The loading from snow and ice shall be taken into account when it is expected to exceed 0,75 kN/m2. NOTE In conditions when there is high humidity and rain or snow and the structure is below freezing point, icing can occur. In such a case an allowance should be made. Maximum ice density is 920 kg/m3. 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 "Q3" 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 Q2 in addition to the effects caused by imperfections (see 9.3). 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. 8.2.3 Variable transient imposed actions, "Q4" 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 of the casting segment. In no case shall the additional allowance be less than 0,75 kN/m2 nor need it be greater than 1,75 kN/m2. This additional load shall be deemed to act on a square area of plan size 3 m × 3 m, see Figure 3. Where the concrete thickness is not constant over the area of 3 m × 3 m, an average value shall be adopted as the basis for calculating the self-weight. SIST EN 12812:2008



EN 12812:2008 (E) 15
a) Cross section during concreting
b) Loading diagram Key 1 access areas: minimum live loading class 1 of EN 12811-1 2 loading from the weight of concrete to be supported 3 surcharge allowance for heaping during placing concrete Figure 3 — Loading from concrete on falsework 8.2.3.2 Concrete pressure Lateral concrete pressure shall be considered in the design. NOTE The National Annex may give information on lateral loads. Published guidance can be found in:  DIN 18218:1980;  CIRIA Report No. 108, Concrete pressure on formwork, 1985;  Manual de Technologie: Coffrage; CIB-FIB-CEB 27-98-83. 8.2.4 Wind "Q5" 8.2.4.1 Maximum wind Data shall be obtained from EN 1991-1-4, which gives velocity pressure for a 50-year return period. NOTE The velocity pressure may be modified according to EN 1991-1-4 taking the period of use of the falsework into account. 8.2.4.2 Working wind For the working wind, a velocity pressure of 200 N/ m2 shall be used. 8.2.5 Flowing water actions "Q6" 8.2.5.1 Loads produced by flowing water The static pressure taken to represent the dynamic pressure of flowing water, qw in Newtons per square metre, shall be calculated from Equation (4):
qw = 500 x vw2 (4) SIST EN 12812:2008



EN 12812:2008 (E) 16 where vw is the speed of water flow, in metres per second. The load caused by water flowing around members, Fw, in Newtons, shall be calculated from Equation (5):
Fw = qw × η × A (5) where A is the effective area normal to the flow, in square metres; η is the force coefficient for water appropriate to the members under consideration. The effective water area A should be determined after investigating the maximum flood level. NOTE 1 The following are some values of η:  1,86 for flat surfaces normal to flows;  0,63 for cylindrical surfaces;  0,03 for well streamlined surfac
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