Mechanical Analysis Of Surveillance And Control Of Construction For The Super-spanned Steel Truss Bridge

With the rapid development of smelting technology of steel, more and more steelof high strength, good flexibility, excellent fatigue and resistance to corrosion hasemerged continuously since the1950s, and the bridge construction has also obtainedthe enormous development. At present the main structure forms of international anddomestic steel bridge are steel box girder structure, long span steel truss structure,steel pipe pole or steel box arch structure and steel composite beam structure. Amongthese, the large steel truss arch bridge is an ideal bridge type crossing the river anddeep ravine because of the advantages of rational bear force, light weight, highstrength, high stiffness and so on.Based on the super-spanned steel truss arch bridge, which is on the high-speedrailways and crosses the highway, this article has done the theoretical research on thestress and deformation monitoring during the incremental launching constriction phase.The multiple-point incremental launching method is used in the construction of thissuper-spanned steel truss arch bridge. In order to ensure the construction safety andmake the stress and deformation meet design requirements of the super-span steel trussbridge, the security monitoring is a key technology for the super-spanned bridgeconstruction. This thesis is to study the security monitoring in the process of thesuper-spanned steel truss arch bridge construction.The author has described the development situations of domestic andinternational steel truss bridge, and makes a brief exposition of theoretical methods aswell as the purpose and principles of the steel truss bridge construction monitoring.Then finite element analysis software MIDAS/Civil has been used to do the stress anddeformation numerical analysis of this bridge during every incremental launchingconstriction phase. The finite element analysis in the thesis is mainly to obtain thestress and line-type variation law of the girders and truss-arches, which include thestress and displacement variation law of part-cantilevered and part-simple-supportedstatus of bridge. The stress monitoring of the key parts in this bridge is being doneduring every incremental launching constriction phase with strain gauges at the sametime. Through the analysis and comparison, the stress measured values agree well with the computed results of MIDAS/Civil. In the actual construction process, constructioncontrol personnel can find the problems timely by the comparison of calculationresults and measured values, which could provide practical and feasible ideas for thenext step of safety construction and achieve the purpose of construction monitoring.Thus，the construction safty of this super-spanned bridge could be ensured.