Effect of shear lag on flexural stiffness of Π-shaped girder in cable-stayed bridges
Zhou Shijun Song Gang
1. School of Civil Engineering, Chongqing University, Chongqing 400045, China;
2. Key Laboratory of New Technology for Construction of Cities in Mountain Area (Chongqing University), Ministry of Education, Chongqing 400045, China;
3. Guizhou Transportation Planning Survey & Design Academe Co., Ltd., Guiyang 550081, China
Abstract：The effect of shear lag on flexural stiffness of Π-shaped composite girder in cable-stayed bridge was analyzed according to actual dynamic construction process. Based on variational principle, a practical beam element including the coupling of shear lag deformation and deflection of Π-shaped composite girder was deduced by introducing a simplified shear lag warping displacement function. In this method, two shear lag degrees of freedom were employed at each node of the element, so that it could be treated that the saltation of boundary conditions for shear lag caused by concentrated bending moment in cable-stayed bridges, and the changes of loads and boundary conditions in dynamic construction process. Combined with a certain Π-shaped composite girder cable-stayed bridge, the numerical analysis results were obtained, and were compared with measured data. It was shown that the presented method had good effectiveness and accuracy. It was also shown that the flexural stiffness of Π-shaped composite girder in the cable-stayed bridge was decreased due to the shear lag effect, and that this effect is greater in cantilever construction stages than that in the last stage of construction. For the cable-stayed bridge concerned in the paper, the effect of shear lag on flexural stiffness of Π-shaped composite girder in cantilever construction stages is about 2~7% for middle span and about 3~12% for side span, which is relatively smaller than that of simply-supported and continuous box girders.
周世军 宋刚 . 剪力滞对斜拉桥中Π形主梁弯曲刚度影响分析[J]. 土木工程学报, 2018, 51(1): 106-113.
Zhou Shijun Song Gang. Effect of shear lag on flexural stiffness of Π-shaped girder in cable-stayed bridges. 土木工程学报, 2018, 51(1): 106-113.
