Seismic Response Analysis Of A Long-span Cable-stayed Bridge With Consolidation System Of Tower Beam And Pier

As an important infrastructure project in China,the bridge is an important part of the transportation lifeline and an indispensable part of China’s regional development.China is a country prone to earthquakes.The frequent occurrence of earthquakes has severely threatened the safety of our bridges.Once the bridges are damaged,the damage caused may be incalculable.It is understood that there has been no serious damage to the collapse of the long-span cable-stayed bridge in China,but the seismic damage of the Taiwan Jilu Bridge has caused the re-entry of the seismic response and seismic performance of the full-concrete cable-stayed bridge of the tower-pier consolidation system The vision of the person.In this paper,the Hejiang Yangtze River Second Bridge is used as the engineering background,and Midas Civil finite element analysis software is used to establish a long-span cable-stayed bridge with tower,beam and pier consolidation system.The dynamic characteristics are analyzed and studied,and the response spectrum method and time history are used The analysis method analyzes its seismic response and explores its laws.The main contents and conclusions are as follows:(1)Briefly describe three theoretical analysis methods commonly used in earthquake resistance of bridges,and briefly list related calculation formulas.Briefly describe the theoretical analysis method of pile-soil interaction,and focus on introducing its dynamic analysis model.According to the characteristics of this project,determine the pile-soil dynamic analysis model.(2)Establish two models considering pile-soil interaction and not considering pile-soil interaction,analyze the natural vibration characteristics of these two models respectively,and study the pile-soil interaction on the tower,beam and pier consolidation system Influence of natural vibration characteristics of long-span cable-stayed bridges.The results show that the pile-soil interaction reduces the overall stiffness of the structure,the structure’s natural vibration period becomes longer,and the frequency decreases;the pile-soil interaction has a greater influence on the side-bending vibration mode of the main beam of the second Hejiang Yangtze River Bridge.(3)Use the response spectrum method to study the effect of pile-soil interaction on the seismic performance of long-span cable-stayed bridges with tower,beam and pier consolidation systems.The results show that the pile-soil interaction increases the displacement and axial force response of the structure,and reduces the bending moment and shear response of the structure.(4)Input the seismic wave parameters suitable for the site parameters of the bridge site,only the dynamic time history analysis of the piled model under consistent excitation,and compare with the seismic response spectrum analysis,compare the two methods to analyze the dynamic response of the cable-stayed bridge Difference;adopt the relative displacement method and consider the traveling wave effect to carry out multi-point excitation seismic response analysis of the pileless model,and further explore the effect of wave velocity on the displacement of key nodes and the distribution of internal forces in key cross sections.The seismic design of the bridge provides a reference.The results show that: the time history analysis method significantly improves the displacement response and internal force response of the key nodes of the structure,and the vertical displacement response of the main beam is the largest;when the wave speed is less than 2000 m / s,the traveling wave effect responds to the structural displacement and internal force.The influence is greater.After exceeding the wave speed,the response values of the structure tend to the response results under consistent excitation.