Research Of The Joint In Composite-concrete Continuous Beam Bridge

In recent years，with the development of large span bridge, Steel–concretehybrid structure is a lot of large span bridge application. This hybrid structuregives full play to the advantages of concrete and steel, this kind of structure hasgood integrity、 high stiffness、 Strong carrying capacity、 good dynamicperformance、 small weight, And the construction convenient than otherstructures, The bridge performance is improved greatly.In the steel-concrete composite beam bridge, steel and concrete beams areconnected by joints, because the steel and concrete is the stiffness of two kinds ofmaterials with different intensity, so the joints under the action of stress, theshape of the dimensions of the joint mutation caused the joint local internal forceincrement. Steel concrete joint is a weak point in mixed structure.This paper takes Chongqing Yangtze River bridge railway bridge as thebackground project, the bridge is completed and open to traffic in September24,2006. The bridge uses combination form of prestressed concrete continuous beambridge girder bridge and continuous rigid frame bridge. Bridge span arrangementis87.75+2x138（Prestressed concrete continuous beam bridge）+2×138+330（The steel box girder of main span）+132.5（continuous rigid framebridge）, the main span from left, right sides of111m prestressed concretecantilever and intermediate108m steel formed steel concrete composite structure.The bridge has a main span of up to330m, The bridge broke the world record forthe largest span, The bridge in order to avoid the prestressed continuous rigidframe generated by the self weight of too much stress is difficult to improve theability to cross question.,in the main span of330m used in108m steel, Iteffectively solves the influence of excessive weight span prestressed concretecontinuous rigid frame problem.Composite beam gives full play to the advantages of concrete and steelbeam, So the composite beam has the advantages of high bearing capacity. At thesame time composite beam has small weight, reduce seismic effect, convenientconstruction, good structural ductility and some other advantages. Compositebeam of this kind of structure has been widely applied to structural design. because of the characteristics of composite beams, design of hybrid structure isnew in the original bridge foundation of Chongqing Yangtze River bridge railwaybridge；The composite beam bridge with330m main span in the original108msteel replacement, Then in section of the joint combined with dynamic analysis,analysis of concrete composite beam joint force.The main contents:(1) Collect, collate the literature summary of mixed structure and joints of therelevant theory and research status.(2) To establish the bridge model and new combination-concrete compositebeam finite element model using MIDAS CIVIL, calculate two kinds ofmodel of joint in the most unfavorable load combination under the action ofearthquake.(3) Using the finite element software ANSYS to establish the steel-concretejoint and combined concrete joint finite element model, the static analysis.(4) The calculation results of stress joints of each component, detailedcomparison and analysis, the hybrid beam joints under earthquake stressrange and stress distribution, And put forward opinions.