PGA amplification factor spectrum of mainshock-aftershock sequence-type ground motions based on equal damage
Strong aftershocks often occur after earthquakes,increasing the extent of structural damage.Thus,the influence of aftershocks on structures in seismic design and structural damage assessment is an important topic.In this study,the NGA-West2 database was used in establis-hing the date set of mainshock-aftershock sequence-type ground motions.Based on damage equiv-alence theory,the peak ground acceleration(PGA)amplification factor under mainshock-aftershock ground motions was defined.Then,the average PGA amplification factor spectra of the structure with a single degree of freedom system under different relative intensities and differ-ent site conditions were obtained through dynamic time-history analysis.The prediction equation of the PGA amplification factor spectrum was constructed through regression analysis,and the discreteness of the statistical results was analyzed.Results show that the PGA amplification factor spectrum is less affected by site conditions but affected by the relative intensity of main-shock-aftershock ground motions,and the value of the amplification factor spectrum decreases with increasing period.The spectral prediction equation can provide the PGA amplification requirement of the mainshock under target damage,and it can be used as the adjustment coeffi-cient of a design spectrum.In addition,this equation considers the influence of aftershocks in a seismic design and structural damage assessment of a structure.
万方数据
维普
