EN 1004-2004 pdf download.Mobile access and working towers made of prefabricated elements – Materials, dimensions, design loads, safety and performance requirements.
– serviceability limit states.
At ultimate limit state the design value for the effect of actions, that is the design value of an internal force or moment, Ed, shall not exceed the design value of the corresponding resistance, Rd in accordance with the expression
Ed d
The design value, Ed, for the effect of actions is calculated from the characteristic values of the actions specified In 8.2 and 8.3 by multiplying each by the corresponding partial safety factor. y.
The design value of the resistance, Rd. is calculated from the characteristic resistance values specified in 11.3 by dividing by a partial safety factor,
At serviceability limit state the design value for the effect of actions specified in the serviceability criterion, Ed, shall not exceed the limiting design value of the relevant serviceability criterion. Cd
Ec ≤ Cd
11.2 Structural analysis
11.2.1 Choice of a model
The models adopted shall be sufficiently accurate to predict the structural behaviour level taking into account the imperfections given in 11.2.2.
The analysis carried out by checking separate planar systems shall consider the interaction.
11.2.2 Imperfections
11.2.2.1 General
The effects of practical Imperfections, including residual stresses and geometrical imperfections, such as out of vertical, out of straight and unavoidable minor eccentricities shall be taken into account by suitable equivalent geometrical imperfections.
The method of application shall be in accordance with the respective specifications of the relevant design documents, for example, for steel EN 1993-1-1, for aluminium EN 1999-1-1. Deviating from these specifications, the assumptions concerning imperfections in global frame analysis shall comply with 11.2.2.2.
The equivalent geometric imperfections need not be geometrically compatible.
the overlapping length of the spigot is at least 80 mm and
the play between the nominal inner diameter of the tube and the nominal outer diameter of the spigot is not greater than 2 mm.
This assumption applies to tubular members with external diameters not exceeding 60 mm.
If one of these requirements is not met, for example if spigots according to EN 74 are used, the joints shall be modelled as an ideal hinge. Alternatively, a detailed check on the spigot and the standard may be made (see
11.3.3.2).
11.2.3.2 Connecting devices
The realistic load-deformation behaviour of the connecting devices shall be incorporated in the model for the analysis. Alternatively joints may be modelled by assumptions which are on the safe side.
NOTE ENV 1993-2 and EN 1281 1-3 give some info4’mation on serni-ngid connections.
For the determination of the relevant parameters for semi-rigid connecting devices in prefabricated towers, see EN 12810-2.
Where the connections to standards are made by prefabricated joints, for example in a modular system, the design moment-rotation characteristic of ledger-to-standard or transom-to-standard connections shall be determined.
11.2.4 Resistance
11.2.4.1 General
The characteristic values of the resistances shall be calculated using the characteristic values of the mechanical properties (for example the yield strength f, j, which are given in EN 12811-2 or may be taken from relevant documents
For steel or aluminium members the resistances shall be determined in accordance with 5.4 of EN 1993-1- 1:2005 or 5.3 of EN 1999-1-1 respectively.
11.2.4.2 Connecting devices
To establish the characteristic values of resistances for
a) connections covered by the scope of structural engineering regulations: see relevant design documents;
b) semi-rigid connection devices for prefabncated towers: see EN 12810-2 and EN 12811-3;
C) other connection devices which do not comply with a document: test shall be carried out. See e.g. EN 12810-2.
11.3.3.3 Joints between tubular members
When the requirements of a rigid connection between tubular members according to 11.2.3.1 are met, the spigot only needs to be verified for the design bending moment at the joint.
When the oveclap is less than 150 mm – respectively 80 mm – and the joint is not treated as an ideal hinge. see 11.2.3.1, the detailed structural design check shall include the bending stresses, shear stresses and local bearing stresses.
11.3.3.4 Side protection
Components of the side protection shall withstand the accidental load specified in 8.3.2.1 without failing or disconnecting. A displacement from the original line of more than 300 mm at any point is to be taken as failure. Where necessary the displacement may be calculated by assuming a pLastic hinge, which transfers the plastic bending resistance of the component.
11.3.4 ServIceability limit state
It shall be verified that the deflection requirements specified in 8.4 are met.EN 1004-2004 pdf download.