Three Dimensional Simulation Analysis Of Large Span Steel Truss Arch Bridge

Large span steel truss arch bridge has been constantly applied due to the advantages of its rich expressive force,majestic appearance and the strong span ability.But with the increasing of its span,construction becomes more and more difficult.In order to further improve the construction technology of large span steel truss arch bridge,using Zhuhai Hengqin bridge as the research background,mainly researching the key construction technology of heavy pressure,reasonable cable force and so on.The span of Hengqin bridge is100+400+100m,using cantilever hoisting method mainly.It is very important to ensure the stability against overturning of the bridge during the construction process by using the cantilever erection method.In order to balance the overturning moment during cantilever construction,the method of applying heavy pressure near the fulcrum of side span is adopted.To establish three-dimensional finite element model of Hengqin Bridge by ANSYS program.Using birth and death element method and adopting the reverse disassembly method to obtain the weight of pressure in different stages.It can be ensure that the coefficient of overturn stability can meet the requirements of specification in the entire construction process.In the cantilever construction control of the arch bridge,the buckle force is direct affects the structure construction,the internal force and the alignment of the completed bridge.Therefore,it is necessary to study the accurate calculation method of the buckle force with the objective of the internal force safety and the ideal shape of the completed bridge.According to the characteristics of cantilever construction method,three common cable force calculation methods are introduced in this paper,and tries to propose an improved method on this basis.This method take “the linear is main and the cable force is subsidiary” as the control principle of construction linear.Not only the calculation principle is simple,but also can solve the problems in the three common cable force algorithms.The displacement of the cantilever end,counterforce of the support and the stress of member under the main working conditions are monitored to meet the requirements of the construction safety and the non-stress closure is realized finally.Part of the design difficulties of super long span steel truss arch bridge during the construction process are solved through the study;and it provides reference for reasonable weight and cable force design scheme of super long span steel truss arch bridge.