How to Utilize the Anti-Optimization Analysis to Treat Uncertainty in Seismic Excitation?

In the paper an approach to treat uncertainty in the response of structures under the action of earthquakes is presented. The main problem is focused in the unpredictability of the seismic accelerograms, and the research effort points at identifying the set of admisible quakes by a few basic parameters (duration, peak acceleration, gross information on the power spectrum, ...). The influence of the details of ground shaking, that really have a very significant influence on the structure’s performance, is approached by the institution of a worst-case scenario. The basic idea is to build up a consistent model for the seismic hazard at the site, and to set up some rules which ground shaking must fit. Hence, the worst combination of details of the quake is sought by a search procedure, aiming at identifying the earthquake producing the extremum of some response parameters, in the set of admissible quakes. In the paper a number of r5eference models are set up, and results referred to a particular seismic area, the Campania region in Italy, are drawn, proving that the procedure is efficient and, to some extent, practical.