Analysis Of Shear Lag Effect On Wide Single Box Three Rooms Prestressed Concrete Continuous Girder Bridge

with the development of transportation, the traffic flow for the width of bridge deman ds more and more high, single box three rooms and single box multicell bridge are present in great numbers. Due to the difference of the distribution of the shear flow in the webs when the box girder is bended, the distribution of shear lag effect of alar plate in multicell box girder is different from single cell box girder or double box girder. The existing research mainly focuses on the research of single cell box girder and the double box girder has certain research as well. How to consider the particularity of the shear lag effect of three or more room box to set up the corresponding analysis method is very necessary. In this paper, the shear lag effect of varied height continuous box beam bridges is analyzed by the engineering background of HongGuang road Fenghe Bridge. The mai n works and achievements are:1.This paper first introduces the development situation of prestressed concrete continuous rigid frame bridge, and overview the state of the methods of the shear lag phenomenon.2.In this study, the minimum potential energy variation method has been adopted in organizing the calculation formula of shear lag effect of box girder, and also for the calculation formula of simply supported beam and cantilever beam of equal cross section. Meanwhile, the analysis and discussion about the shear lag effect of box girder of variable cross section is on the basis of finite difference method. The results which calculated by the theoretical formula introduced by the variation method for the shear lag effect and by the finite element software are comparative analyzed.3.Taking the HongGuang road Fenghe Bridge as engineering background, this paper use the plane bar system program(MIDAS/CIVIL) and the space finite element program(ANSYS) to build the plane and space finite element model of the bridge, and the analysis on the shear lag effect of 0# block and the mid-span of the HongGuang Fenghe Bridge are made.4.Based on the finite element analysis, the influence of box beam web width, thickness, web height, width of flange plate of box girder, transverse width change on the shear lag effect is analyzed. Through analysis and comparison, the above factors on the shear lag effect of box girder have certain effect, but the degrees of influence of each are not identical. Reasonable suggestions for design are put forward, and the research results have a certain value to the design of box girder bridge.