Comparative study of seismic structural response to real and spectrum matched ground motions

Developing the concept of performance based analysis and design has made the nonlinear dynamic analysis an efficient method for quantification of the seismic response of structures. Generally, this analysis is done by utilizing accelerograms which are ground motions obtained from earthquakes. This research is focused on assessing the seismic structural response of a comprehensive set of reinforced concrete moment resisting frames under excitation of real accelerograms and ground motions which are spectrally matched to a target spectrum. Matching process is conducted in the time domain and ASCE 7-05 spectrum is used as the target spectrum. Comparisons are provided for a number of ground motion parameters and the effect of spectrum matching has been investigated. Additionally, variation of structural response and the degree of compatibility and conservation of real and spectrally matched ground motions has extensively discussed. It is shown that spectrum compatibilization effectively decreases the variation of structural response. However, the measure of observed bias is thoroughly depends on the height of the structure. Finally, fragility curves of structural performance are provided and it is indicated that considering modeling uncertainties result in obtaining a fragility curve with reasonable resemblance to that obtained from real ground motions.