Vertical Ground Motion Simulations And Analysis Of Vertical Seismic Response Characteristics Of RC Bridge Structure

The ground motion effect in near fault area has obvious vertical seismic effect.At the present time,considering the influence of vertical ground motion,the dynamic analysis of 1/2-2/3 is usually carried out by horizontal ground motion.However,the ground motion observation records in the near fault area show that the peak value of vertical acceleration is likely to exceed the peak value of horizontal acceleration.At the same time,it is also found that the damage of many bridges can not be explained by the traditional horizontal seismic control.In this paper,the influence of the seismic response of reinforced concrete bridges under non uniform excitation input and vertical ground motion excitation are studied.(1)The synthesis of near fault earthquake motion field.According to the inversion of the fault rupture model and the vibration characteristics,and using a hybrid method based on finite fault model,the ground motion of three stations in a typical near fault earthquake is synthesized.Compared with the process of recording and Fourier amplitude spectrum,the correctness and effectiveness of the proposed method is verified.(2)A finite element model for reinforced concrete bridge.Based on the previous study of the nonlinear dynamic response characteristics of reinforced concrete continuous bridge structure,a finite element model is established to simulate the nonlinear mechanical properties of reinforced concrete beam bridge pier,abutment bearing and by using OpenSees platform.And the dynamic characteristics of the model are analyzed and then validated correspondingly.(3)Effect and parameter analysis of vertical se ismic effect.The effect of vertical earthquake action o n the response of the bridge under different fault distances is preliminarily studied using the Synthetic Near fault earthquake motion field.This method is also used as non-uniform seismic excitation at different fault distances.In addition,the variation of seis mic behavior of reinforced concrete bridges under the non-uniform excitation input with different vertical earthquake acceleration peak value and horizontal earthquake acceleration peak(V/H)ratio are studied.