Influence Of Pier Beam Connection Mode On Seismic Response Of Beam Arch Composite System Bridge

Earthquake is one of the most serious natural disasters.In recent decades,earthquakes have occurred frequently,which has brought great threat to human life and property safety.Bridge for connecting the two ways of transportation,when the bridge is subjected to seismic action,will be severely damaged,and will lead to secondary disasters,so that people’s life safety and property safety suffered two damage.Today,the cross-section of the bridge is smaller and smaller,the weight is also more and more light,but the ability to grow stronger.Concrete filled steel tubular arch bridge is a new type of beam bridge,which has the advantages of large span,light weight and so on.In this paper,a new structure of high arch bridge as the engineering background,using the finite element software MIDAS Civil modeling calculation,analysis of the dynamic characteristics and seismic response,the main contents are as follows:(1)Introduction to the theory and method of seismic analysis.In this paper,the development of the theory of seismic analysis is introduced,including the static analysis method,response spectrum method,time history analysis method and the basic principle and application scope of the static elastic-plastic analysis(Pushover).(2)Dynamic characteristics analysis of beam arch composite system bridge.In order to investigate the influences of the bridge pier and beam connections on the seismic response of the MIDAS to Civil are built "double pier,a pier consolidation,a pier bearing two pier bridge connection model to calculate its dynamic characteristics,and analyze its natural frequency and vibration characteristics.Found two connections four modal characteristics are basically the same,and the first order modes are "floating bridge";pier beam connection node just by double pier into a pier piers,the first ten frequencies are decreased;when the vibration mode corresponding to the same mode for longitudinal displacement,both in the modal difference;when the vibration mode corresponding to the same mode for the transverse displacement,both in the modal difference is small.(3)Response spectrum analysis of beam arch composite system under earthquake action.The combination of three directions in which the action of the earthquake is taken into account is the combination of six combinations.According to the code for seismic design of railway bridge,the standard response and rare earthquake spectrum analysis of two calculation model of rib "arch" and "1/4 arch" and "dome" in three typical sections and bridge piers under earthquake displacement and internal force.Two connection mode has little influence on the lateral displacement of the bridge,a greater impact on the vertical displacement,vertical displacement is greater than the maximum horizontal displacement of arch rib in the earthquake,the maximum horizontal displacement of pier top are smaller than the maximum vertical displacement;compared to a pier,a pier bearing "and" double side connection type pier,arch the rib and longitudinal direction of the bridge pier top displacement,arch longitudinal and vertical to the bridge pier axial force,transverse bending moment increased significantly.(4)Analysis of beam arch composite system under earthquake action by time history analysis.In combination with the three directions of seismic action considered by the response spectrum method,six combinations are set up.According to the seismic code,the railway bridge with 1940,El Centro 180 Site Deg wave,it was modified to regulate the available earthquake acceleration 0.02 g,earthquake acceleration of two kinds of seismic waves of 0.11 g seismic response analysis.Three typical sections of arch foot,1/4 arch and vault of two model arch rib are calculated and analyzed.The displacements and internal forces of piers under earthquake action are analyzed.It is found that the connection between pier and bridge is calculated by time history analysis and response spectrum method.The results obtained are the same under the action of earthquake.(5)Analysis of beam arch composite system under seismic loading by static plastic analysis(Pushover)method.The seismic analysis of the pier and longitudinal direction of the consolidation pier of the two model under the rare earthquake is carried out by using the Pushover method.The capacity curve is plotted and the ductility requirement is checked.It is found that the ratio of ductility is smaller and the structure is more safe than that of "double pier consolidation" and "one pier consolidation" and "one pier support".