5.2.1 General notes

When considering the partial safety concept, the various ultimate limit states (ULS) and serviceability limit states (SLS) must be verified: that is to say, the actions Ed must not exceed the structural resistance Rd to be considered in each case. For these limit conditions, following DIN 1055-100 [52], we distinguish between a number of effects:

— independent constant actions Gk

— independent actions of pre-stressing Pk

— dominant independent variable actions Qk1

— other independent variable actions Qki (i > 1)

— extraordinary actions Ad

— effects due to earthquakes AEd.

When designing nuclear power plants, the effects designated as external or internal actions (cf. Section 5) can be assigned to the group of ‘extraordinary actions’ or ‘earthquake actions’. These are pre-given as design values (see Section 5), so that implicitly a partial safety factor is given a value of 1.0 and the design basis earthquake to KTA 2201.1 [37] is given a weighting factor g1 to DIN 1055-100 and the importance factor to DIN 4149 [39] is taken as 1.00. All other effects are to be stated as characteristic values.

Design and Construction of Nuclear Power Plants. First Edition.

Rudiger Meiswinkel, Julian Meyer, Jurgen Schnell.

© 2013 Ernst & Sohn GmbH & Co. KG. Published 2013 by Ernst & Sohn GmbH & Co. KG.

To obtain the reference values for these actions, we need to examine different combinations to DIN 1055-100. We distinguish between design situations, as follows:

Ultimate limit state

— Permanent and temporary design situation

— Extraordinary design situation

— Design situation due to earthquake

Serviceability limit states

— Rare (characteristic) combination:

— Frequent combination:

— Quasi-permanent combination:

5.2.2 Partial safety factors and combination factors for actions

Partial safety factors g of effects may be assumed to DIN 1045-1 [21]. Recommended coefficients of combinations factors C to KTA-GS-78 [51] and DIN 25449 [15] are stated in Table 6.1.