Analytic Study On The Lateral Bracing System Design Of Concrete Filled Steel Tubular Arch-bridges

The lateral bracing system of concrete filled steel tube through tied-arch bridge is composedof transverse-braces and transverse beams, there are much more design alternative fortransverse-braces, different design alternative have very important influence on the bridgestructure, and transverse beams carry load directly, its stress is complex. If design work isimproper, it may lead to crack appear on transverse beams. In this way, repairing work will bedifficult because the large number of transverse beams. Therefore, analytic study on the lateralbracing system design of concrete filled steel tubular arch bridges has very important practicalsignificance. This thesis is based on the background of JinYu bridge, this thesis establish the finiteelement model of arch-bridge by the design graphs, in order to study the design oftransverse-braces and transverse beams.First of all, this thesis analyses rationality of design scheme of the bridge. According to theresults of its static and stability analysis, this paper selected six design plans of transverse-bracesto comparative study on transverse-braces, middle transverse-braces and diagonaltransverse-braces. For concrete filled steel tube through tied-arch bridge in this paper,transverse-braces design has its necessity. In choosing middle transverse-braces in the design,brace type X affects the stability safety factor rate is obviously superior to brace type1, weshould select it. Diagonal transverse-braces setting effects play an important role on the stabilityof arch-bridge, we should try to avoid only1type braces design.Secondly, this paper studies the static and stability of the middle transverse beams. On thebase of it, the writer changes the constraint conditions at the ends of the middle transverse beams,its models formed simply supported model and consolidation model, this paper make acomparative study of simply supported model, consolidation model and elastic build-in model.The writer analyzed the differences and relations of three middle transverse beams design models.The analysis results in this paper show that the force of the elastic build-in model is betweensimply supported model and consolidation model. During preliminary design and other specialdesign phase, the negative bending moment of beam end can be calculated on the consolidationmodel, the bending moment of beam transverse can be according to the calculation model ofsimply supported, stress can be calculated according to10%greater than the consolidation model,the deflection can be according to the calculation model of simply supported.