Static And Dynamic Research And Arch Foot Local Stress Analysis Of Long-span Concrete-filled Steel Tubular Arch Bridge

Concrete-filled steel tubular arch bridge plays an important role in the bridge because of its good mechanical properties,strong spanning ability and unique shape.With the development of concrete-filled steel tubular arch bridge in China,its span increases gradually,and the static and dynamic characteristics of long-span concrete-filled steel tubular arch bridge show certain law under load because of the difference of structural stiffness distribution in space.the study of its law is of great significance to guide bridge construction and structural optimization.This paper takes Tangjiahe Bridge as the research background,uses the finite element software Midas Civil to establish the whole bridge simulation model,uses the finite element software Midas FEA to establish the arch foot solid model,and analyzes the static characteristics,dynamic characteristics and dynamic response of the concrete-filled steel tubular arch bridge.the work of this paper is summarized as follows:(1)The static analysis,dynamic analysis and the research status of arch foot of concretefilled steel tubular arch bridge are summarized,the deficiency of existing research is pointed out,and the research idea of this paper is put forward.the research is carried out from three aspects:static analysis,dynamic analysis and arch foot.Finally,the research background is briefly introduced.This paper expounds the establishment process and solving method of the motion equation,as well as the local analysis theory of the arch foot,which lays a theoretical foundation for the follow-up analysis.(2)The design scheme of Tangjiahe Bridge is introduced,and the construction process of concrete-filled steel tubular arch bridge is simulated by finite element software,and the deformation,stress and internal force of the bridge are calculated.The bearing capacity and stability of the main components are checked with reference to the code.The structural size of the arch foot,the selection of the most unfavorable working conditions of the arch foot and the extraction of the internal force of each control section are introduced in turn.The solid model of the arch foot is established by using the finite element software Midas FEA,and the stress distribution of the arch foot before and after sealing is analyzed.(3)Considering the effects of dead load,lane load,wind load,shrinkage and creep and temperature,under the combination of dead load,live load and eight kinds of loads,the deformation,internal force and stress of the bridge and the crack width in the middle span of the bridge deck are calculated.According to the code,the bearing capacity of the main members and the fatigue stress of the main arch joint are checked.The effects of rise-span ratio and arch axis coefficient on the static characteristics of up-through concrete-filled steel tubular arch bridge are analyzed.(4)The Lanczos method is used to analyze the natural vibration characteristics of the bridge,and the effects of different transverse brace arrangement,transverse brace stiffness,risespan ratio,arch rib spacing and superstructure stiffness on the natural vibration characteristics of the bridge are studied.The time history analysis method is used to analyze the influence of different speed and different vehicle spacing on the dynamic deflection of Tangjiahe Bridge.On this basis,the influence of impact load on the dynamic deflection of Tangjiahe Bridge is discussed.The driving comfort of the bridge is evaluated with reference to the vibration feeling index.