Study On Mechanical Properties Of Wavy Steel-concrete Composite Arch Bridge In Construction Stage

In recent years,China’s bridge construction has entered a period of rapid development.Among them,multi span arch bridges with strange appearance and beautiful shape are increasingly widely used.In bridge construction,whether the stress state of the bridge meets the design requirements is an important measure to evaluate whether the quality of a bridge meets the standard.The construction process of arch bridge is complex,and the stress state of the structure is closely related to the construction process.Therefore,the research on the mechanical properties of beam arch composite system bridge construction process has very important engineering significance and practical value.Taking a wavy multi span steel box arch bridge in Guangyuan as an engineering example,this paper uses the numerical simulation method to simulate the bridge,and carries out the research on the construction sequence of beam arch,the stress characteristics of key components in the construction process and the optimization scheme of system transformation.The main research contents are as follows:(1)Relying on a wave shaped multi span steel box arch bridge in Guangyuan,a spatial finite element model is established by using Midas/Civil finite element software.The stress of structural components such as main beam,steel box arch and concrete arch section in the completed state of the multi span steel box arch bridge under different beam and arch construction sequences is compared and analyzed,and the most reasonable construction sequence is obtained,which provides basis and theoretical guidance for the construction of similar projects.(2)For the corrugated steel box arch bridge with reasonable beam and arch construction sequence,the stress performance of the main beam during the process of tensioning the main beam prestress in the construction process is studied,and the tensioning time of the main beam prestress is determined;The influence of temperature effect during the assembly of steel box arch rib is analyzed,and the stress and deformation laws of steel box arch rib under temperature effect are obtained to ensure the smooth closure of steel box arch rib;The influence of the prestress of the tensioning main beam on the concrete arch during the hoisting of the steel box arch is analyzed,and the stress of the concrete arch section is obtained to ensure the structural safety.(3)According to the relevant calculation theory of determining the cable force of cablestayed bridge,this paper uses the rigid supported continuous beam method,zero displacement method and minimum bending energy method to determine the reasonable Suspender Force of arch bridge.Through the comparative analysis of the structural displacement,bending moment and Suspender Force of arch bridge in the completion stage under the dead load of arch bridge,it is obtained that the suspender force determined by minimum bending energy method is the most reasonable Suspender Force;Draw up three kinds of suspender tensioning schemes,take the completed Suspender Force determined by the minimum bending energy method as the goal,use the forward iteration method to determine the suspender initial tension under the three schemes,compare and analyze the suspender initial tension and arch rib stress under different schemes,and obtain the most reasonable suspender tensioning scheme of the arch bridge;The influence of temperature difference on Suspender Force is analyzed,and the change law of Suspender Force under temperature difference is clarified to ensure the reasonable stress of suspender,so as to improve its service life.