The Research On The Stability And Model Test Of The Long-span Cable-stayed Arch Bridge

Cable stayed arch bridge is a kind of new combination bridge appeared in recent years, its theories studies to still be placed in a beginning stage so far. Cable stayed arch bridge as arched bridge with cable stayed bridge of combination system, its stability is an important link of design and construction.This paper studies the stability of cable stayed arch bridge, combined the main bridge model experiment of the fourth bridge of Xiangtan Xiangjiang river.In summarizes the predecessor to the segmental arch surface and outside in flexure critical load computational method foundation,with the principle of the minimum potential energy, an analytical solution for the lateral critical bucking load of cable stayed arch bridge is studied. In this foundation,taking the Xiangtan Xiangjiang River four bridges which constructs as the project background, the 3-D finite element model was built and the stability of three load cases is studied using the common finite element method software-ANSYS, considering geometric nonlinearity and material nonlinearity. The result indicate that the influences of geometrical nonlinearity is different to the structure critical load under different load cases.Under the live uniform load, the structure critical load decreases 10% after considering the geometric nonlinearity; and under the live uniform load or concentrated load act on half bridge, the structure critical load decreases 35.38% or 74.08% after considering the geometric nonlinearity. And under the three load cases, the critical load of the cable-stayed arch bridge taking into account double nonlinearity is much smaller than taking into account linear elasticity or geometrical nonlinearity.Therefore if we want to estimate the limit bearing capacity exactly, the double nonlinearity must be considered. In this paper, the influence of lateral connections and stayed cables to the stability of cable-stayed bridge is studied. The result indicates that the layout of lateral connections influence to the stability more greatly than the rigidity of lateral connection; The stayed cables can help much on increasing the stability of cable-stayed bridge; The force of stayed cables have something to do with the stability of cable-stayed bridge, higher the force, higher the stability coefficient.At last, in order to study the practical stability performance of the Xiangtan Xiangjiang River four bridges, a total bridge model test was carried through. From the test results we can know that under the dead load and quadruple designing live load,...