Resonable Prestressing System Of Main Girder For Large SPAN 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, three kinds of layout, three kinds of bending angles, two kinds of anchored position, the relations between different anchored positions and bending angles of longitudinal prestressed strands; the reason of persistent pressure unevenness for conventional tensioning sequence, five kinds method of improved persistent pressure, two kinds of layout of transverse prestressed strands; five kinds of layout and two kinds of tensioning of vertical prestressed strands; and causes of cracking for main girder, are analysed and discussed in the thesis.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.