Main Girder Prestress System Esign And Construction Technology Research For Largespan Continuous Rigid-Framed Bridge

The advantages of prestressed concrete continuous rigid-framed bridge, such as traffic smooth, simple structure, good structural performance, easy construction, maintenance with low cost, and this kind of structure almost becoming the first selection for bridge of main span in the range from100m to300m, are summarized and reviewed in this thesis.Labajin Bridge is a prestressed concrete continuous rigid-framed bridge of105+2×200+105m spans on Ya’an to Lu’gu highway. Taking it as the research project, after a series of research investigation.Through the establishment of space finite element model.five kinds of layout of vertical prestressed strands; and causes of cracking for main girder, are analysed and discussed in the thesis and do different vertical prestressed steel beam lateral arrangement effect research;At the same time, relying on the big bridge engineering LaBa jins, according to the construction phase analysis vertical prestressed tensioning effect, compared to conventional tension and hysteresis tension two kinds of different construction process of vertical prestressed tensioning effect, at the same time pay attention to in the construction process, the Dragon Boat Festival period of not tensioning vertical prestressed, in construction loads tensile stress distribution, this paper puts forward the vertical prestressed steel beam rational tensioning way.For the prestressing system of large span continuous rigid-framed bridge, this thesis puts forward suggestions for reasonable structural form, tensioning sequence of the prestressed strands, measures to prevent cracking of the main girder. The results of this study has been to good uses in the design and construction of Labajin Bridge, also may provide reference for other bridge for the same type structure.