Azarbakht - PhD Student, IIEES, Tehran, I.R. Iran, Research visitor at the University of Ljubljana
Dolšek - Assistant Professor, Faculty of Civil and Geodetic Engineering, University of Ljubljana, Slovenija

A methodology has been proposed which can be used to reduce the number of ground motion records needed for the accurate prediction of the summarized seismic response (16%, 50% and 84% fractiles) of structures by means of incremental dynamic analysis (IDA). The reduction in the number of ground motion records for accurate prediction of the summarized IDA curves is achieved by introducing a precedence list of ground motion records. The determination of such a list is an optimization problem, which is solved in the paper by means of a genetic algorithm technique. The seismic response of a simple, computationally non-demanding structural model has been used as input data for the optimization problem. The presented example is a three-storey reinforced concrete building, subjected to a set of twenty-four ground motion records. It is shown that the summarized IDA curves can be predicted with an acceptable accuracy by employing only four ground motion records instead of the twenty four, which is the total number of ground motion records for the predefined set.