Study Of Load Effects For Curved Continuous Prestressed Concrete Bridges

With the rapid development of expressway and main road, more and more interchanges and fly-over crossing will be built. The curved box girder bridges have been adopted more and more in the bridge project of interchanges and fly-over crossing because of good performance of structure and features of economy. But at the same time, a lot of issues such as the cracking of interchanges, the large lateral displacement etc emerge one by one in recent years. Some issues have exerted a negative and severe impact on the normal operation, which proves that there are still some problems remaining unsolved in curved bridges.This thesis focuses on the design proposal of some continuous curved girder bridge in Nei Meng, mainly discussing and analyzing the problems about deformation, internal force, constraint reaction of bearings and etc. Midas/Civil, a large-scale FEM software package is used to model and analysis.Firstly, mechanical characters of the curved girder bridge are analyzed systemic in the thesis. On the base of understanding several traditional computation theories that could holistically analyze the curved girder bridge, grasp the application method of FEM theory and calculate the curved girder bridges to solve estimation problem.Then, has analyzed the pre-stressed load effect, the concrete shrinkage and creep effect as well as the temperature load effect specifically to the curve girder bridges, at the same time rests on "the general code for design of highway bridges and culverts " (JTG D60-2004) which promulgates newly, has carried on the analysis and the research to its computation pattern and stipulation.Then, with the FEM software Midas/Civil builds the computation model of some curved girder bridge in Nei Meng, calculates the distortion, internal force and the constraint reaction of bearings which produced by the action of dead load, pre-stressed load, concrete shrinkage and creep, system temperature and gradient temperature, summarizes the load effect rule by analyzing the estimateddata, and discovers the reason of curve girder bridge's "creeping" phenomenon, by this token, proposes some design preventive measures.Finally, analyzes some curve girder bridge in Nei Meng with several kind of typical vehicle load according to the new and old code for design of highway bridges and culverts, compares the main girder's bending and torsion moment and the mid-span bottom surface tensile stress caused by different vehicle load. According to front analysis result, summarizes the difference between different load effects caused by vehicle load according to the new and old code for design of highway bridges and culverts.