Study On Static Behavior Of Bridge Widening Of Continuous Rigid Frame Bridge With Prestressed Concrete Box Girder

With the increasing traffic in China, a large number of early constructed roads andbridges cannot meet the requirements of transportation. So far, more than half of the highwaynetworks are in reconstruction. Taking the reconstruction of Bei Jiang Bridge as background,which located on the section from Xiebian to Sanbao belonging to the national highway fromShenyang to Haikou, using finite element analysis program of Midas Civil2010, this thesisstudied on the mechanical behavior of lateral jointing of continuous rigid frame bridge withprestressed concrete box girder.Firstly, through finite element analysis, this paper researched on additional internalforces, which caused by the differentials of shrinkage and creep of concrete between rebuiltbridge and newly-built bridge after the lateral connection of the two bridges The resultshowed that: there exists more serious impact on the newly-built bridge than that on therebuilt bridge. The differentials of shrinkage and creep of concrete between rebuilt bridge andnewly-built bridge the differentials of shrinkage and creep of concrete between rebuilt bridgeand newly-built bridge engendered axial compression in newly-built bridge, while itgenerated axial tension in rebuilt bridge. The lateral shearing force, lateral bending momentand torsion in newly-built bridge is greater than that in rebuilt bridge, and there was a contrarylaw on vertical shearing force and vertical bending moment of the two bridges. Moreover, atbridging stage, the regularities of distribution and the variation trend of the internal forces ofthe two bridges was discussed, and the optimum time for connecting was determined that thebridges can be connected6months after the rebuilt bridge was erected.Secondly, internal forces and stress of Beijiang Bridge, which caused by supportsettlement is studied through finite element software. By comparing results of3conditions,The results showed that: the settlement of case3(the pier of No.29and No.31of rebuilt bridgesettled simultaneously) had the most obvious impact on the internal force and stress of thenewly-built bridge and post-casted parts.Finally, the bridging stage of Beijiang Bridge is analyzed, and the result showed that thealignment of the bridge is smooth. The maximum deflection of the bridge is-8mm, and thedifferentials of elevation between newly-built bridge and rebuilt bridge are all relatively small.the maximum differentials of elevation between the two bridge is3mm. The result of analysison Beijiang Bridge on serviceability limited state showed that the roof and floor ofnewly-built bridge and rebuilt bridge are in a state of compression, while the change of stress in post-casted parts is less, which in a range of-2.00MPa~2.5MPa. The stress of the bridge isunder the standard value of compressive and tensile strength. The stiffness of Beijiang Bridgeand strength of crucial section were checked. The result showed that the stiffness stiffnessmeets the specifications, the flexural and shear capacity of crucial sections meet therequirement as well.