Analysis of Acceleration Peak Ratios and Response Spectra for Near-Fault Earthquakes
NI Yong-jun,ZHU Xi(School of Civil Engineering and Architecture, Beijing Jiaotong University, Beijing 100044,China)
Based on the earthquake records (Classified according to the fault distance and soil sites) from recent major earthquakes, a statistical analysis concerning of the acceleration peak ratio of vertical and horizontal components are carried out. It is shown that the mean values of acceleration peak ratios for near-fault and medium-fault records are greater than the design values coded in the existing Chinese seismic codes, while the one for far-fault records is closed to the coded value. The statistical analysis respecting to the response spectra of horizontal acceleration records shown that the mean spectra of dynamic amplification factors calculated from the records recorded on hard and medium sites were greater than the design value coded in the existing Chinese seismic codes, while they were consistent with the value coded in UBC97. It hinted that the design spectra of Chinese seismic codes for hard and medium sites were apt to unsafe when they were used in near-fault zones.; the mean spectra for soft sites were consistent with the design spectra of Chinese seismic codes, while they were far less than the value coded in UBC97. The design spectrum of UBC97 for soft sites was inclined to conservative.