COMPARISON OF STRUCTURAL SEISMIC RESPONSE BASED ON REAL AND SPECTRUM COMPATIBLE NEAR-SOURCE GROUND MOTION RECORDS

Abstract. A relatively large set of single-degree-of-freedom systems, for different period, damping and backbone curves, are selected and subjected to two different sets of ground mo-tion records. The first set of ground motion records is consisting of 31 near-source strike-normal ground motion components recorded under forward directivity conditions from four different earthquakes. The 31 prescribed real records are used as “seeds ” to generate the second set of ground motion records which are compatible to the median response spectrum of the first set of records. The single-degree-of-freedom systems response is calculated, then, for the two prescribed sets of ground motion records in different levels of ground motion in-tensities. Recently, this kind of nonlinear analysis, which is called Incremental Dynamic Analysis (IDA), is widely used by many researchers. The nonlinear structural seismic re-sponse, for the two sets of ground motion records, is statistically compared to identify the dif-ferences which are made from the spectrum matching process into the structural seismic response. The results show that the seismic structural capacity in terms of intensity measure based on the spectrum compatible records is biased. On the other hand, the seismic structural capacity in terms of displacement ductility is statistically un-biased