The Analysis About Shear Lag Effect Of A Main Girder In The Self-Anchored Suspension Bridge With An Edge-Girder Section

With the development of highway construction, double-side-girder PC self-anchored suspension bridge is widely used because it meets the human needs of traffic and the landscape. However, this type of bridge, typically, has a large wide-span ratio and aspect ratio, while the girder section in a self-anchored suspension bridge under load will also generate internal forces including bending and axial force, which leads to more significant shear lag effect.Based on the elementary beam theory, this thesis takes shear lag effect into consideration. Considering the shear lag effect of the box beam, energy variation method is used to derive element stiffness matrix and equivalent nodal force vector, and this thesis considers respectively the shear lag effect of the thin-walled box beam under the compact-bending load and axial force with only a vertical load. The plane frame structures procedure is established to explore respectively shear lag effect of the freely supported beam under the concentration and under uniform load, or under compact-bending load, which is compared with the organic glass model test results and finite element model results. In this thesis, it explore not only the impact different vertical loads take on shear lag, but also different axial forces and the same vertical load together,and different cantilever flange width takes on shear lag on top and bottom slabs.Taking The XinGou River Bridge as an engineering background in the thesis, the software BNLAS is used to calculate sling force and anchor span's tension under every sling tension stage, and local model using ANSYS software is established to calculate shear lag effect of the main sections. In every sling tension stage, with the constantly varying of the ratio between the bending moment and axial force, this thesis explores the distribution law of shear lag coefficient on the top and bottom slabs. And also, the shear lag effect of every main section in three designated phases of the operation phase is calculated and analyzed, and studied effects that different forms in which the lane load is imposed in the physical model took on shear lag in every section.