Reliability Evaluation of the Eurocode EN 1990 Safety Factors for Concrete Structures under Seismic Loads

Modern standards for structural design consider the safety verifications in the ultimate limit states (ULS). Uncertainties are inherently present in the evaluation of loadings and resistances. In the deterministic approach, these uncertainties are accounted for through partial safety factors. Nevertheless, a rational basis for evaluating the actual risks of failure can only be achieved by a full probabilistic approach. This paper discusses the reliability levels obtained in the flexural design of a concrete beam, under seismic loading, considering the partial safety factors defined in the Eurocode EN 1990. Two typical situations are analyzed: sites presenting low to medium seismicity and sites with high seismicity. The main issue discussed herein is the criterion for defining the characteristic values of ground accelerations from seismological data. It is shown that, under some conditions the criteria established in Eurocode EN 1998 for defining this variable lead to insufficient reliability levels.