Construction Simulation Analysis Of Long-Span Rigid-Frame-Continuous Combination Bridge

With the improvement of national economic strength, in China the level of bridgedesign and construction has been developed rapidly. In recent decades, the rigid-frame-continuous combination bridges have been applied widely due to its merits, which arecomfortable travel and strong ability to adapt to the terrain. The construction period oflong-span rigid-frame-continuous combination is very long, and the deflection andstress change with the construction process. So the correct analysis of deflection andstress and its distribution law in every construction phase is very important for guidingconstruction and ensuring that bridges meet successfully and finished bridge state meetthe requirements.In this paper, the main bridge of CaiJiaGou Bridge in Chongqing Lichuan Railwaywas taken as the engineering background. The finite element model of CaiJiaGouBridge was set up to simulate the construction process for the result of stress, deflectionand internal force of each girder segment in every construction phase. As the typicalrigid-frame-continuous combination bridge, CaiJiaGou Bridge with span arrangement(80m+3×144m+80m) has three A-shaped piers. And the most highest pier reaches139m.In this dissertation, the main contents and conclusions are as follows:①The development history of rigid-frame-continuous combination bridge wasdescribed in this dissertation. And the disadvantages and advantages of several beambridges were contrasted.②Three main construction simulation analysis of rigid-frame-continuouscombination bridge were described in detail. This paper introduced the finite elementtheory, and the calculation method of shrinkage and creep with its mechanism wasdescribed too.③There was a introduction of CaiJiaGou Bridge. Finite element software MIDAS-Civil was applied to set up a spatial beam model considering all the kinds of loads andthe construction process with activation and passivation.④The calculation results include the internal force, deflection and stress in eachconstruction phase. The results of finished bridge state show that the beam at the rootreserves much positive moment and the beam in the middle of span reserves littlenegative moment. The flexural condition of the main beam is reasonable. The shearanalysis show the shear condition of main girder isn’t reasonable, because the shear caused by presstressed is less than the dead load in most main girder. The stress analysisshow the each section of main girder stays compressed status of whole section and themaximum compressive stress are close to15MPa. The reserve of compressive stress issufficient. The top compressive stress at the root of main girder is larger than the bottom.The top and bottom compressive stress are almost equivalent at the middle of span. Thecondition of stress in main beam is reasonable when the bridge finished.⑤By analyzing the influence of parameters, the deflection and internal force ofprestressed concrete rigid-frame-continuous combination bridge are impacted greatly byparameters including dead weight errors, prestress loss, shrinkage and creep of concreteand temperature. The parameters which have great influence have to be controlledstrictly during the construction period and be adjusted according to the actual situationto ensure the finished bridge state meets the design requirements.