Optimum earthquake design coefficients based on probabilistic seismic hazard analyses; theory and applications

It is common practice to define the seismic design coefficients for earthquake-resistant building codes by choosing a fixed return period, leaving aside considerations about structural vulnerability and acceptable risk levels. This paper reviews the theory of the optimum design, introduced from almost the beginning of the formal probabilistic seismic hazard analysis framework and presents the results of its application in Mexico and Colombia using national seismic hazard models for the two countries. The obtained optimum design coefficients are compared with the ones obtained with the fixed return period approach. Results are presented with the aim of starting to discuss alternative approaches to select, in a more sensible way, the seismic design values included in the building codes.