SEISMIC EVALUATION OF STEEL DUAL SYSTEMS AGAINST ARTIFICIAL EARTHQUAKES

Dual systems in form of steel moment frames accompanied with chevron bracings are among commonly used systems in high seismicity regions in the world. Therefore, the recognition of their seismic behaviour is of high importance. Except a few parts of the world that have sufficient earthquake records, artificial accelerograms can be used in other regions. One method for generating artificial accelerograms is using wavelet transform. In this paper, 5-, 10-, 15- and 20-story structures are designed according to ASCE7 requirements. Spectra matching process is performed for 44 earthquake records. Pushover and nonlinear time history analysis is done in order to investigate seismic behaviour of this system against real and artificial earthquake records. It can be concluded that responses against artificial records has far less dispersion, while the average responses in these two sets of records are approximately the same.Incremental dynamic analysis is done, and adjusted collapse margin ratios are calculated, in order to check whether frames can meet the FEMA-P695 criterion. Fragility curves are obtained to know the probability of collapse for these earthquakes.