Seismic Behavior Of Continuous Girder Bridges With Different High Pier Structures

With the rapid development of bridge technology in my country,the structural forms of high piers continue to diversify.The types commonly used at present are mainly column piers,solid bridge piers and hollow thin-wall piers.Due to its construction convenience,economy and other advantages,the double-column pier is more widely used in highway bridges with a pier height less than 40 m.However,the double-pillar high-pier continuous girder bridge with a pier of up to 35 m or more is characterized by a large superstructure,and the entire bridge structure has the characteristics of "top-heavy",which is easy to cause the bridge to respond more dynamically under seismic loads.This is a double-column type.The seismic design of high-pier continuous bridges puts forward higher requirements.In order to explore the seismic performance of continuous girder bridges with different high pier structure forms,this paper takes the Shiping Second Bridge as the engineering background,on the basis of discussing the theory of seismic methods,analyzes the dynamic characteristics of three different pier bridges and uses responses Three seismic analysis methods,spectrum method,uniform excitation analysis and power spectrum analysis method,are used to analyze the seismic performance of the bridge structure,and the reasonable choice of the pier structure in the seismic design of the high-pier continuous beam bridge is obtained.The main research contents of this article are as follows:1.Based on the basic principles of structural dynamics,using the Ansys finite element software with the "Shiping Viaduct Second Bridge" as an engineering example,three finite bridge models with different pier types were established,and the dynamic characteristics of the three different pier bridge structures were analyzed..Studies have shown that the self-vibration period of double-column pier bridges is greater than that of solid rectangular thin-wall pier bridges and hollow rectangular thin-wall pier bridges.2.Analyze the seismic performance of the three types of bridge structures,and obtain the displacement at the top of each pier and the internal force at the bottom of the pier.The results show that: compared with the other two pier types,the double-column pier can reduce the bridge structure in the earthquake Under the internal force response,and in compliance with the displacement calculation,it has good seismic performance.3.Introduce the basic theory of the viscoelastic artificial boundary of the site model and the input method of seismic waves,and determine the scope of the two-dimensional site model and the size of the element based on the relevant theoretical knowledge.The propagation law of the Taft wave perpendicular to the two-dimensional site model after beingaffected by the terrain effect is discussed.It is found that the concave terrain has an amplified effect on the ground motion,and the ground motion response gradually increases from the bottom of the slope to the top of the slope on both sides;the slope on a slower slope,the increase in seismic response is also gentler.4.Study the influence of terrain effect on the seismic response of high-pier continuous girder bridges with different high-pier structures.The results show that the seismic response of each bridge pier when considering the effect of terrain effect is greater than the consistent excitation analysis.In addition,the increase in seismic response of hollow rectangular thin-walled piers is smaller than that of solid rectangular thin-walled piers;while the peak displacement peaks and internal force peaks of double-column piers have the largest increase.By reasonably designing the location and number of beams,Still meet the displacement check.Therefore,in the seismic design of a high-pier bridge with a pier height of about 40 m,a double-column pier can be used.In summary,through the study of the seismic performance of continuous beam bridges with different high pier structures,the application range and reasonable choice of pier type for high pier continuous beam bridges are obtained,and the seismic analysis of high pier bridges in concave terrain Response characteristics.It is hoped that the results of this study can provide a reference for the seismic performance analysis of high-pier continuous beam bridges and the design of seismic design of bridge pier structures.