Study On The Main Arch Ring Structure And Construction Method Of Long Span Steel-Concrete Composite Arch Bridge

To increase the arch span, use materials reasonably, and reduce the weight of arch ring as the starting point, the project of a new special long-span steel-concrete composite system arch bridge is presented, in which arch foot of reinforced concrete box structure and mid-span to vault of steel material box structure are included. Around the long-span arch bridge construction problems, the construction plan, combining cantilever casting of reinforced concrete arch ring and cable erecting steel box, is raised, and structural mechanics of construction stage is analyzed with finite element software. In this paper, main work and achievements are as follows:①On the basis of wanzhou Yangtze river bridge, the design of deck type of steel-concrete composite structure arch bridge is put forward. The clear span of main arch ring is420meters:the section of100meters range is reinforced concrete box with single-box3-cell, and the section of220meters range is steel box with single-box3-cell. By study of the section of arch ring, linear, rise-span, ratio, spandrel construction, steel and concrete joint construction, ANSYS finite element space truss model is set up,and according to analyze, the arch ring of internal force caused by the segment point location variation, arch axis coefficient, stability coefficient variation, the scope of design parameters for steel-concrete composite arch bridge is obtained.②According to the current design specifications of highway bridge and culvert and design code for the steel structures, the finite element models are built to calculate bearing capacity and analyze stability of the designed arch bridge by Midas/Civil and ANSYS, then the results are suitable.③To reduce concrete arch ring hanging segment weight, speed up the suspension casting, the arch ring is divided into two side box and a box in the roof and floor, two concrete box construction by the cantilever method, two steel arch box side box cantilever construction method is used to install, implement both sides box single box closure, closure after first installation and welding of steel arch roof and floor, then install concrete roof and floor, loosen the guy finally make the main arch ring structure.④For cable hoisting construction in steel box section, two plans are presented: steel arch box lifting integrally and hoisting segmentally, using ANSYS finite element software to calculate the process of the main arch ring construction, then to analyze stress, cable force, transformation of arch ring in these two construction process, the mechanical behavior regulation of concrete arch ring is concluded under cantilever casting in concrete section, lifting integrally and hoisting segmentally in steel section, long-span arch bridge, steel-concrete composite arch bridge, segment point, cantilever casting.