Seismic Fragility Analysis Of The LRB Base-Isolated Structure Under Pulse-Like Ground Motions

Pulse-like ground motions will have a great impact on mid-long period structures.Seismic isolation structures that consume seismic energy by installing seismic isolation bearings to increase structural damping will theoretically be more sensitive to pulse-like ground shaking.Therefore,this paper will carry out research on the identification and decomposition of pulse-like ground motions and the vulnerability performance of Lead Rubber Bearing(LRB)base seismic isolation structures.The main research of this paper is shown below.(1)The ground motions are filtered by energy indicators,and the selected ground motions are identified by the wavelet packet translation(WPT)to extract the pulse signal and retain the residual signal.The obtained pulse-like ground motions are used for the LRB foundation isolation structure seismic analysis.The structural response results have a good linear relationship with the coupling results of the energy indicators,which can be used as the intensity index of the selected pulse-like earthquakes for vulnerability analysis.(2)The Incremental Dynamic Analysis(IDA)of the original,extracted,and residual signals of 80 pulse-like ground motions was completed in turn.The corresponding vulnerability curves were plotted based on the obtained structural response data.Comparing the structural response results of the three signals,it was found that the extracted pulse signal compared with the original signal,and the residual signal both have a stable proportional relationship.(3)Under the same seismic action,the possibility of structural damage to the superstructure of the LRB foundation isolation structure is much smaller than that of damage to the isolation bearing.It is in line with the requirement of "Strong structure,Weak component" for Chinese seismic design.