On reliability perception of seismic hazard estimates used in structural design

State-of-the-art approaches for the seismic hazard assessment of a site of interest are mainly based on the development of the classical probabilistic seismic hazard analysis (PSHA). A PSHA allows defining the values of a set of ground shaking intensity measures at a site of interest, given an acceptable exceedance probability in a fixed time interval. In this way, structures are designed to bear uniform hazard spectra derived from PSHA results, as prescribed by most of the seismic codes adopted worldwide. However, PSHA estimates are often subject to debate every time a severe earthquake occurs. For this reason, in the framework of the PSHA methodology, the main aim of this study is to propose a reliability-based approach for assessing seismic hazard estimates subsequently used in structural design. The time-exposure of the structure was revealed to be a crucial parameter, evidencing why classical PSHA is representative of the “long-run case” in which the time interval of the earthquake catalogue goes to infinity.