Study On Shear Lag Effect Of π-shape Girder Of Curved Cable-stayed Bridge And Model Test

Shear lag effect is a problem that can not be neglected in bridge design.However,at present,the study of shear lag effect of curved cable-stayed bridge is very scarce.With the curve cable-stayed bridge being widely used in engineering,the research on the shear lag effect of curved cable-stayed bridge has been paid more and more attention by engineering community.With a curved cable-stayed Bridge in the Brazzaville taken as the research background in this paper,a research of the shear lag effect on π-shape girder of curved cable-stayed bridge during the construction process is carried out based on finite element calculation and a model test.At the same time,the shear lag on the π-shaped main girder of the cable-stayed bridge with different design parameters was studied,which can provide some basis for the optimization of the main girder of curved cable-stayed bridges.Following aspects have been completed in this paper;1.The necessity of the study on shear lag effect on π-shape girder of curved cable-stayed bridge was introduced briefly.What’s more,the development of curved cable-stayed bridge and the research status of shear lag of straight-lined bridges and curved bridges were summarized in detail.And then the problems and shortcomings in there researches were pointed out.2.Through the analysis of the bending and torsion of the main girder of the cable-stayed bridge,the internal force of the main beam is classified into two kinds of loads which were the in-plane load and the load perpendicular to the plane.The effect of these two kinds of loads on shear lag was analyzed as well.3.By assuming the warping function of the shear lag and combining the energy variation method,the closed form general solution of vertical bending coupling with torsional shear lag was produced;and by combining the boundary conditions,the result expressions of vertical bending stress and warping stress were acquired;4.By performing the finite element analysis of the Congo Brazzaville Riverside Avenue bridge during the whole construction process,the change rule of the shear lag in the construction process was acquired.Subsequently,the influence of various design parameters which include the curvature radius of main beam,the thickness of top plate,the height of edge rib and the thickness of diaphragm plate on the shear lag effect of curved cable-stayed bridge with π-shape girder was analyzed;5.Based on the engineering background,a model bridge with the scale of 1:20 was designed to verify the effect of shear lag and the effect of curvature radius on the shear lag of the curved cable-stayed bridge.