Development of Comprehensive Guidelines for Preprocessing Simulated Acceleration Time Histories

Drexel University, Philadelphia PA

Investigators

Abstract

Abstract At the present time, the seismic response evaluation of lifeline systems incorporating spatial variability relies solely on simulated ground motions. Numerical (finite element) codes permitting spatially variable motions as excitations at the structures supports require displacement time histories as input excitations. Displacement time histories obtained through direct double integration of simulated acceleration time histories do not exhibit realistic waveforms, because, due to purely numerical reasons, accelerations can contain large random amplitude variability in the low frequency range. Hence, such simulated acceleration time histories also require preprocessing. There is, however, no agreed-upon approach for their preprocessing and the preprocessing scheme is left to the discretion of the investigator. This study will utilize recent developments in seismology, extend them to the specific needs of simulated and conditionally simulated time histories, and provide guidelines for their preprocessing. The following steps will be undertaken: (i) selection of commonly used simulation schemes from the ones available in the literature to be investigated in this study; (ii) application of state-of-the-art preprocessing schemes developed by the seismological community to simulated motions; and (iii) quantification of the results of step (ii) through the evaluation of the response statistics of a simple structural model subjected to spatially variable excitations. The development of the guidelines, along with user-friendly (MATLAB) codes will be posted on the World Wide Web for direct use by the community.