Study on the Dynamic Response of Cross-sea Double Arc Towers Cable-stayed Bridges by Near Fault Earthquakes
In order to investigate the pulse and non-pulse seismic dynamic response of a cable-stayed bridge with double curved towers,a 3D spatial finite element model with the geometric nonlinearity of the cables was first estab-lished by Midas/Civil 2019 to analyze the structural natural vibration characteristics;Secondly,based on the seis-mic intensity at the bridge site,a certain number of pulse and non-pulse seismic motions were selected to be the ex-citation sources for seismic response analysis;Finally,the structural internal forces,key position displacements,cable stresses,and stress amplitudes under pulse and non-pulse seismic actions were investigated.The research re-sults indicate that all the the bending moment,tower bending moment,and shear force of the main beam under pulse seismic action are greater than the response values under non pulse seismic action.Moreover,under longitu-dinal and vertical seismic excitation,the bending moment and shear force of the main beam only have one peak.But under lateral and vertical seismic excitation,there are two peaks;The displacement response under pulse seismic action is greater than that under non pulse seismic action.The maximum lateral displacement response is at the mid span main beam with approximately 176.8 mm;From the aspect of seismic excitation,the longitudinal displacement under longitudinal earthquakes is greater than the transverse displacement,while the transverse displacement under transverse earthquakes is greater than the longitudinal displacement;The maximum stress of the cable under pulse seismic action is 175 MPa,and the stress fluctuation amplitude reaches 100 MPa.
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