Modeling of the seismic action for new concept of performance-based design.

In the last decades the modelling of the seismic action had a common trend with the analysis of the structures from the seismic performance point of view. The new concept of performance-based earthquake engineering (PBEE) takes into account the probabilistic specification of strong ground motions. The probabilistic modelling is based on: the geological and seismological characteristics of the site (seismic hazard), the recurrence period of the seismic event, the annual probability of exceedance, the occurrence modality and the intensity of the seismic action. Although the deterministic approach provides an easy method to determine the seismic hazard, it doesn't take into account the uncertainties from the estimation of the seismic hazard and does not use the earthquake's occurrence frequency in the calculus. The probabilistic approach permits the embedding of the uncertainties and earthquake's occurrence frequencies. Thus, the seismic hazard is expressed using an exceedance probability and it can be compared with others types of seismic hazard. This paper deals with new trends of knowledge management in modelling the seismic action, in order to fit into the new format of PBEE.