Study On Construction And Mechanical Behavior Of Steel-concrete Composite Beam System Of Half-through Concrete-filled Steel Tube Arch Bridge

In recent years,a large number of half-through concrete filled steel tube arch bridges have been built in China.Steel-concrete composite beam bridge system is widely used in the half-through concrete filled steel tube arch bridge because of its light weight,good mechanical performance and convenient construction.The design method and calculation theory of half-through concrete filled steel tubular arch bridge have been studied deeply in China,but few studies have been made on the structural form,mechanical behavior and construction of steel-concrete composite beam bridge.For this reason,based on the engineering background of Guizhou Jiangkaihe River Bridge and Matan Hongshuihe River Bridge in Laibin,Guangxi,the construction and mechanical behavior of steel-concrete composite beam bridge system are studied by numerical analysis method.The main research contents are as follows:?Study on the structure of bridge system of half-through arch bridge.This paper introduces the development process of the half-through arch bridge system,and divides the half-through arch bridge system into four categories: simply supported bridge system,continuous bridge system,continuous bridge system and steel lattice bridge deck system.The structural form and characteristics of the structure are studied by examples.?Modeling and mechanical behavior of steel-concrete composite girder bridge system.Aiming at the complex modeling of wet joint pouring process of prefabricated bridge deck,a new method to simulate the boundary conditions of bridge deck and bridge deck,bridge deck and bridge deck is put forward based on the stress characteristics and construction methods of steel-concrete composite beam system.The finite element analysis of the whole construction process of bridge deck system is carried out,and the simulation methods of key parts are listed.Based on the results of finite element analysis,the deformation,internal force,stress and self-vibration characteristics of the two bridges during operation are studied,and the influence of the non-uniformity of Suspender Force on the steel-concrete composite beam bridge system is analyzed.?Cause analysis and Solution Research of large tension stress of bridge deck.In view of the large tension stress of the deck in the finite element model of Matan Hongshuihe River Bridge,the causes of this phenomenon are analyzed from the aspects of deck deformation and concrete shrinkage and creep,and the solutions are put forward.?Study on Construction Optimization of half-through concrete filled steel tube arch bridge.Combining with the simulation results of finite element software and the factors of construction site,the optimal sequence of the construction of the roadway beam of Guizhou Jiangkaihe Bridge is put forward.According to the influence of one-time tension and pre-lifting of bridge deck on bridge deck alignment and Suspender Force of completed bridge,the optimum scheme of hoisting bridge girder is put forward.The stress analysis of each scheme is carried out to determine the reasonable pouring sequence of wet joint of prefabricated bridge deck of Jiangkaihe Bridge and cast-in-situ concrete of Hongshuihe Bridge of Matan.