Analysis of Shear Lag Effect in Construction Process of Broad Prestressed Concrete Cable-Stayed Bridge

The Jinqiao Bridge in Wuhan is a single pylon prestressed concrete cable-stayed bridge with span arrangement of(138+81+41)m and with double cable planes.The main girder adopts the separated double-side box cross section with variable width and the widest part is 49.899m.The main span is constructed by the cantilever cast method,while the side spans are cast on scaffoldings.In order to examine the law of stress distribution at different locations of the main girder cross section and to guide the construction control and monitoring of the bridge,the ANSYS was used to set up the full-scale model of the bridge to simulate the construction process of the main girder,and analyze the shear lag effect in the top and bottom plates of the front section of the MB3and MB2segments under different load cases during the construction process of the MB6 segment.The results shows that the girder of the bridge is broad and the shear lag effect is distinct,and the shear lag effect in the top plate is much more noticeable than that in the bottom plate,the prestress has very limited effect on the shear lag effect of the cross section,the prestress shows more significant effect on the cross section shear lag effect in the vicinity of the prestress acting zone near the pylon.And concentrated load also has greater influence on the shear lag effect.