Analysis On Seismic Behavior And Exploration On Seismic Control Of Stiff Skeleton Concrete Filled Steel Tube Arch Bridges

Earthquake is one of the major natural disasters.In the past20centuries,the average number of deaths due to the earthquake reached17,000people per year, however bridge is very important in traffic link and it is the lifeline engineering. So studying seismic performance of bridge is very important,now many long-span Bridges are doing damping research.The southwest of China is a high intensity area and the main location is the valley gully. So large span concrete filled steel tubular arch bridge as a kind of bridge form of southwest area is very common.At present the seismic and damping analysis on large span concrete filled steel tubular arch bridge is very little.This paper takes qian yu line ye lang river bridge as the engineering background,and use finite element software MIDAS to carry on the numerical simulation,establish space finite element model, analyze the earthquake response,set damping device and analyze damping.Specific work of this paper in the following areas:(1)First introducing seismic response analysis method.Introduce the fundamental and scope of the static method, the response spectrum method, the basic principles of time-history analysis method and random vibration method, but ultimately chose the response spectrum method and time history analysis.(2)Second seismic response analysis of arch.establish ye lang river bridge space finite element model through finite element software MIDAS in this article,study dynamic characteristics analysis;Determine the bridge’s natural vibration mode and vibration model,and study the dynamic characteristics.The results show that the lateral stiffness of the bridge is weak and the overall stiffness is not very good.(3)Then on the basis of the characteristic analysis of natural vibration,study structure of large span concrete filled steel tubular arch bridge seismic response spectrum and time history analysis.Consider the longitudinal, horizontal, vertical and combination under the action of earthquake to analyze the seismic response of large span concrete filled steel tubular arch bridge.(4)While carrying on response spectrum analysis,research the analysis of different seismic wave input angle(0°,30°,45°,60°,90°) and the influence of the internal force and displacement of arch bridge,and then compare the results of consistent excitation time history analysis with the results of response spectrum analysis.The results show that the largest majority of the seismic response of arch input angle is45°and60°,however the results of consistent excitation time history analysis are generally larger than the results of the analysis of the response spectrum analysis. (5)The ye lang river arch bridge are analyzed in the non-uniform excitation,And emphatically analyze traveling wave effect how to influence on seismic response of the arch bridge.Select wave speed150,300,600,300,1200,1500,1800,1500,1800m/s nine wave speed to carry on the contrast analysis.Study the effect of wave velocity on the large span concrete filled steel tubular arch bridge.(6)Finally study reduce isolation device’s selection and research the best index of viscous dampers to study stiff skeleton concrete-filled steel tubes arch bridge damping analysis.The results show that arch has the best damping effect when the speed index is0.5.