The Mechanical Model And Comparison Of Steel Truss-web Composite Bridge

The steel truss-web and concrete composite bridge is different from traditionalconcrete box girder by using steel web to substitute concrete web, and compose the crosssection with the concrete roof and floor. The problem of concrete crack is solved, and thestructure has better permeability and appearance. Steel truss-web composite bridge hasseveral characters such as specific mechanical behavior, light self-weight, quicklyconstruction and low cost. It has been more and more frequent with the wide applicationin overseas but been still in research stage, and lacked of standard in China. Based on this,in this thesis, the mechanical model of composite bridge was summarized, the reasonablefinite element model of steel truss-web composite bridge in engineering was put forward,and the mechanical properties was analyzed, in order to provide advices can be taken forreference in application of engineering.In this thesis, three models were created used finite element analysis software Ansysand Midas Civil, which were solid model, basic beam gird model and fine beam girdmodel. The precision of beam gird model was analyzed and compared with solid model,the model was checked with support reaction, and two different load cases were created toanalyze the mechanical properties. Moreover displacement, deflection and stress werecompared to verify the feasibility of using beam gird model for steel truss-web compositebridge in engineering design. The results showed that beam gird model have enoughaccuracies, and made the structure safer.In addition, the solid model was used to analyze shear lag effect of steel truss-webcomposite bridge. Three parameters were selected for analysis, which were thickness ofsteel truss-web, concrete roof and floor. Different values of geometric characteristics wereused to analyze the effects on effective width ratio. The results showed that shear lageffect existing in the steel truss-web composite bridge, and near the support was moreobvious. Meanwhile, the effective width was affected of different degrees by the changing of geometric parameters. Calculation was needed to determine the reasonable size of steeltruss-web composite bridge.