The Study Of Ultra Wide Box Girder Under A Variety Of The Condition Of Supporting Beam

With the development of the urban construction and transportation, urban bridge con-struction quantity increased, which puts forward new requirements for bridge construction. Ultra wide box girder arises at the historic moment. What’s more, due to the larger lateral torsional rigidity, small deformation, simple construction technology, wide box girder is widely accepted. However, the existence of ultra wide box girdered to the stress of transverse beam, a crucial part of bridge structure, more complicated. In the practical project of the de-sign process, the reliability and safety of simplified structure mode of transverse beam must be taken into consideration and verified. As a result, the working cycle is extended and the efficiency of design is descended.On the basis of the actual design project, the research and analysis of simplified structure mode of the transverse beam is carried out. Firstly, the current domestic research achievement about the transverse beam stress of wide box girder bridge are introduced, meanwhile the fi-nite method,element analysis, calculation of unit, general provisions are describe. Secondly, a typical three-span PSC continuous wide box girder bridge in Wei-Qi Road project in Nanjing is analyzed. The stress distributions of typical sections are achieved under construction stages and vehicular load. Based on the analysis of grillage method and solid finite element software, the stress pattern of three-span PSC continuous wide box girder bridge and transverse beam was analyzed and calculated the effective width of critical section and shear lag. Then, the computed result by the simplified structure mode of the transverse beam is verified The con-clusion is drawn as follows:(1)Spatial effect of ultra wide box girder structure is appreciable.(2)Beam support has a influence on deflection obviously. When the bearing arrangement spacing is big, the deformation of the beam is similar to the simply supported beam. On the contrary, it is similar to the cantilever beam when spacing is small.(3)Spatial calculation shows that force of box girder transverse is not shared by the top and bottom plate and web evenly. Load bore by outer webs is smaller and load bore by inner webs is beam web is influenced a lot by internal bearing arrangement.(4) To the prestressed concrete continuous box girder structure,as for double bearing and multiple bearing the webs, top plate and bottom plate bear the internal force of transverse beam together. The simplified model of transverse beam takes six times thickness of bottom plate and top plate as effective width model is practically feasible.(5)The simplification of the dead load and live load at the bearing meets the engineering requirements.