Effect of Saturated Complex Site on the Seismic Response of Continuous Long-span Beam Bridges
In China,many long-span bridges are situated across saturated complex sites characterized by soil saturation,undulating to-pography and superimposed water,in which the propagation of seismic waves induces spatial variations in ground motions due to scat-tering effect.However,the seismic records under such specific site are lack.Addressing this concern,we establish a multi-point ground motion simulation approach to analyze the seismic response of long-span bridges in saturated sites.Initially,the boundary element method is employed to solve the ground motion transfer function of saturated sites.Subsequently,the spectral representation technique is used to synthesize spatially varying ground motion acceleration time-histories.Conclusively,a continuous five-span beam bridge is set as an example,and the seismic response is investigated to study the impact of local site effects and hydrodynamic pressures on the seismic behavior of the continuous beam bridge.The results indicate that the peak ground acceleration in the saturated regions has signi-ficantly spatial variances,and multipoint input can cause the peak acceleration of seismic motion in a saturated site to be amplified by 2～3 times.Consequently,situation leads to a 95％～110％increase in the displacement of the pier top compared to the results under uni-form ground motions.Furthermore,dynamic hydrodynamic pressure is shown to precipitate pier displacement and internal forces by 34％and 29％,respectively.Disregarding the influence of saturated site conditions when evaluating ground motions and bridge re-sponses for long-span bridges in saturated complex sites tends to engender hazardous outcomes.
Site effectBoundary element methodFinite element methodMulti-support ground motionContinuous beam bridge
万方数据
维普
