2.4.7.4 Verification procedure and partial factors for uplift

(1)P Verification for uplift (UPL) shall be carried out by checking that the design value of the combination of destabilising permanent and variable vertical actions (V_dst;d) is less than or equal to the design value of the stabilising permanent vertical actions

where

(2)P The partial factors for G_dst;d, Q_dst;d and G_stb;d for persistent and transient situations defined in A.4 (1)P and A.4 (2)P shall be used in equation (2.8).

NOTE The values of the partial factors may be set by the National annex. Tables A.15 and A.16 give the recommended values.

2.4.7.5 Verification of resistance to failure by heave due to seepage of water in the ground

(1)P When considering a limit state of failure due to heave by seepage of water in the ground (HYD, see 10.3), it shal be verified, for every relevant soil column, that the design value of the destabilising total pore water pressure (u_dst;d) at the bottom of the column, or the design value of the seepage force (S_dst;d) in the column is less than or equal to the stabilising total vertical stress (σ_stb;d) at the bottom of the column, or the submerged weight (G'_stb;d) of the same column:

(2)P The partial factors for u_dst;d, σ_stb;d, S_dst;d and G'_stb;d for persistent and transient defined in A.5 (1)P shall be used in equations 2.9 a and 2.9 b.

2.4.8 Serviceability limit states

(1)P Verification for serviceability limit states in the ground or in a structural section, element or connection, shall either require that:

or be done through the method given in 2.4.8 (4).

(2) Values of partial factors for serviceability limit states should normally be taken equal to 1,0.

NOTE The values of the partial factors may be set by the National annex.

(3) Characteristic values should be changed appropriately if changes of ground properties e.g. by ground-water lowering or desiccation, may occur during the life of the structure.

(4) It may be verified that a sufficiently low fraction of the ground strength is mobilised to keep deformations within the required serviceability limits, provided this simplified approach is restricted to design situations where:

• a value of the deformation is not required to check the serviceability limit state;
• established comparable experience exists with similar ground, structures and application method.

(5)P A limiting value for a particular deformation is the value at which a serviceability limit state, such as unacceptable cracking or jamming of doors, is deemed to occur in the supported structure. This limiting value shall be agreed during the design of the supported structure.

2.4.9 Limiting values for movements of foundations

(1)P In foundation design, limiting values shall be established for the foundation movements.

(2)P Any differential movements of foundations leading to deformation in the supported structure shall be limited to ensure that they do not lead to a limit state in the supported structure.

(3)P The amount of permitted foundation movement shall be selected during the design.

NOTE Permitted foundation movements may be set by the National annex.

(4)P The selection of design values for limiting movements and deformations shall take account of the following:

• the confidence with which the acceptable value of the movement can be specified;
• the occurrence and rate of ground movements;
• the type of structure;
• the type of construction material;
• the type of foundation;
• the type of ground;
• the mode of deformation;
• the proposed use of the structure;
• the need to ensure that there are no problems with the services entering the structure.

(5)P Calculations of differential settlement shall take account of:

• the occurrence and rate of settlements and ground movements;
• random and systematic variations in ground properties;
• the loading distribution;
• the construction method (including the sequence of loading);
• the stiffness of the structure during and after construction.

(6) In the absence of specified limiting values of structural deformations of the supported structure, the values of structural deformation and foundation movement given in Annex H may be used.

NOTE The values of the partial factors may be set by the National annex. Table A.17 gives the recommended values.