Research On Seismic Response Analysis And Optimization Of Seismic Reduction Measures For Curved Rigid Frame-continuous Combination Beam Bridge

The high-low pier large-span curved rigid frame-continuous combination beam bridge is an irregular bridge span structure with more complicated spatial linearity and stress characteristics,Because of its advantages of beautiful linearity,strong crossing ability,smooth driving and strong ability to adapt to terrain and terrain,It is widely used in mountain bridges and highway bridges.However,this type of bridge has a severe bending-torsion coupling effect,and its bridge pier stress state is complex,and it is often in a compound action state with multiple stress forms.Due to the influence of various non-linear factors,such bridges often produce extremely serious earthquake damage under the action of strong earthquakes.Therefore,its seismic response and seismic isolation research have received much attention in the field of bridge engineering in various countries.Therefore,it is of great significance to analyze the seismic response parameters of this type of bridge and optimize the seismic isolation measures.To this end,this paper takes a four-span high-low pier curved rigid frame-continuous combination beam bridge as engineering support,Based on CSiBridge finite element software,the seismic response parameter analysis and optimization of seismic isolation measures were carried out.The main research work and conclusions are as follows:(1)This article briefly introduces the development and stress characteristics of curved rigid frame-continuous composite beam bridges,collects and organizes the research status of curved rigid frame-continuous composite beam bridges at home and abroad,The theoretical basis of seismic design and seismic response analysis of bridge structures is summarized and summarized.(2)Based on the CSiBridge finite element software,a three-dimensional finite element model of a curved rigid frame-continuous composite beam bridge was established.The key parameters of the structure were pile-soil-structure interaction,radius of curvature,and pier height.Subspace iteration method was used to analyze the corresponding bridge structure.The dynamic characteristics analysis was carried out,and the impact of each key parameter on the dynamic characteristics of the bridge structure was compared,and the change rules of the dynamic characteristics such as the period and vibration quality participation coefficient of the bridge structure were analyzed.(3)Taking the types of seismic waves,the excitation direction of the seismic waves,the radius of curvature,the pile-soil-structure interaction and the stiffness ratio of the pier line as the key parameters of the structure,the parameters of the seismic response of the bridge structure were analyzed based on the non-linear time history analysis method,and the comparisons were compared.The influence of each key parameter on the seismic response of the bridge structure,and the variation law of the seismic response of the bridge structure such as the internal force of the pier bottom,the displacement of the pier top,the displacement of the bearing and the displacement of the beam at the top of the pier and abutment are analyzed.(4)This paper briefly introduces the mechanism of seismic isolation and isolation,the mechanical model and finite element simulation method of common seismic isolation devices.The viscous damper was introduced on the basis of the original structure,and the damping coefficient and damping index of the damper were used as the key parameters.The nonlinear time history analysis method was used to analyze the vibration of the bridge structure to verify the damping of the viscous damper.For the seismic effect,the impact of each key parameter on the seismic reduction effect of the bridge structure was compared,and the optimal value of the mechanical parameters of the viscous damper was obtained.(5)Based on the seismic response analysis results of the curved rigid frame-continuous composite beam bridge with additional viscous dampers,different installation schemes of base isolation devices were set up,and the base isolation analysis of the bridge structure was carried out using nonlinear time history analysis method The optimal arrangement plan of the base isolation device is determined.On this basis,the difference between the vibration-damping scheme of only the installation of viscous dampers and the combined vibration-damping scheme of viscous dampers and base isolation devices at the same time is analyzed and compared.The research shows that the two vibration isolation devices of the combined vibration reduction scheme can achieve good complementary advantages.Therefore,the combined vibration reduction effect of the combined vibration reduction scheme is significantly better than that of the single vibration reduction scheme.