Permanent displacement of a bridge column can be directly measured during the inspection after near-fault earthquakes.However,the engineer needs to estimate the expected residual drift at the design stage to determine...Permanent displacement of a bridge column can be directly measured during the inspection after near-fault earthquakes.However,the engineer needs to estimate the expected residual drift at the design stage to determine if the bridge seismic performance is satisfactory.The most direct method to estimate the residual displacement is nonlinear response history analysis,which is time consuming and cumbersome.Alternatively,an attractive but indirect method is generating estimated residual displacement spectra that depend on displacement ductility demand,column period,site conditions,and earthquake characteristics.Given the period and the expected displacement ductility demand for the column,the residual drift response spectra curves can be utilized to estimate the residual drift demand.Residual drift spectra that are applicable to RC bridge columns in different parts of the United States were developed based on nonlinear response history analyses using a comprehensive collection of recorded and synthetic near-fault ground motions and were linked to one-second spectral acceleration(S1)of the AASHTO maps.It was also found that the residual drift ratio is below one percent when S1 is less than 0.6 g.展开更多
WHAT,WHERE,AND WHEN In the early morning of February 6th,2023,an M7.8 earthquake occurred in southeastern T€urkiye near the northern border of Syria.The event initiated a complex sequence of aftershocks,including an M...WHAT,WHERE,AND WHEN In the early morning of February 6th,2023,an M7.8 earthquake occurred in southeastern T€urkiye near the northern border of Syria.The event initiated a complex sequence of aftershocks,including an M7.6 earthquake about 9 h later and 90 km to the north(Figures 1A and 1B).The earthquake sequence is also referred to as a strong doublet earthquake sequence.Aftershocks of the two strong earthquakes occurred along two separate branches of the East Anatolia Fault,with lengths of up to 300 km,and some aftershocks occurred in Syria(NEIC/USGS,2023).展开更多
文摘Permanent displacement of a bridge column can be directly measured during the inspection after near-fault earthquakes.However,the engineer needs to estimate the expected residual drift at the design stage to determine if the bridge seismic performance is satisfactory.The most direct method to estimate the residual displacement is nonlinear response history analysis,which is time consuming and cumbersome.Alternatively,an attractive but indirect method is generating estimated residual displacement spectra that depend on displacement ductility demand,column period,site conditions,and earthquake characteristics.Given the period and the expected displacement ductility demand for the column,the residual drift response spectra curves can be utilized to estimate the residual drift demand.Residual drift spectra that are applicable to RC bridge columns in different parts of the United States were developed based on nonlinear response history analyses using a comprehensive collection of recorded and synthetic near-fault ground motions and were linked to one-second spectral acceleration(S1)of the AASHTO maps.It was also found that the residual drift ratio is below one percent when S1 is less than 0.6 g.
基金funded by National Natural Science Foundation of China(Grant No.42030311,S.N.)US Dept.of Energy Grant DESC0019759(D.Y.)US National Science Foundation Grant EAR-1918126(D.Y.).
文摘WHAT,WHERE,AND WHEN In the early morning of February 6th,2023,an M7.8 earthquake occurred in southeastern T€urkiye near the northern border of Syria.The event initiated a complex sequence of aftershocks,including an M7.6 earthquake about 9 h later and 90 km to the north(Figures 1A and 1B).The earthquake sequence is also referred to as a strong doublet earthquake sequence.Aftershocks of the two strong earthquakes occurred along two separate branches of the East Anatolia Fault,with lengths of up to 300 km,and some aftershocks occurred in Syria(NEIC/USGS,2023).
