Research And Optimization Of Design Parameters Of Steel-concrete Composite Truss Bridge

Steel-concrete composite truss bridge is a kind of bridge structure,which is composed of steel truss and concrete deck.Compared with the traditional steel truss bridge,the composite truss bridge has the advantages of high stiffness,low cost,reasonable force and easy construction.At present,there are few studies on steel-concrete composite truss bridges.Based on the actual engineering of composite truss bridge,the main research work is as follows:Firstly,the structural characteristics,research status,development and application of composite truss bridges at home and abroad are summarized.The existing problems were discussed,and the research contents and technical route of this paper were determined.Secondly,the theory of grillage method,the theory of local analysis of composite truss bridge and the optimization theory of orthogonal test are introduced.This lays a theoretical foundation for the follow-up study.Thirdly,taking composite truss bridge as the research object,the grillage model,shell element model and solid element model of simply supported beam and continuous beam are established by finite element analysis software respectively.The results of three models of simply supported beam and continuous beam are compared and analyzed,and the reliability of each model is verified.The grillage method is used to calculate the jacking construction process of continuous beams under the four working conditions,and the mechanical characteristics of the bridge under the four working conditions are compared.Fourthly,the finite element solid model of composite truss bridge is established by choosing the panel model with larger web force.The girder-grillage model is used to calculate the force of the whole bridge under certain working conditions.Then,the forceson the panel that need to be studied are extracted and applied to the solid element model.In addition,in order to minimize the average stress of the designated reference point,the structural optimization of the upper and lower joints is carried out by orthogonal test method.In summary,based on the engineering background,this paper studies the finite element calculation method,main design parameters analysis,joint design parameters analysis and structural optimization of steel-concrete composite truss bridge,and draws useful conclusions.The conclusions drawn from the study can be used as reference for other similar composite truss bridges.