STUDY ON THE SHEAR LAG EFFECT OF MAIN GIRDER WITH SINGLE BOX AND TRIPLE CELLS USED IN CABLE-STAYED BRIDGES

摘要

Three construction steps including the maximum double cantilever 、 the maximum single cantilever of main girder and completion state are simulated by the spatial finite method on the background of Jianning Bridge. This paper studied shear lag effect of main girder with single box and triple cells based on comparison and analysis of the calculation results that are verified by the test on the bridge. The results show that the shear lag effect of top plate at some section is significant. There is a maximum stress of top plate on the cantilever end of flange. The shear lag effect of bottom plate is less evident than that of top plate; the shear lag effect of some sections on the construction process is more significant than that on completion state of the bridge. This paper puts forward a method that describes the features of the shear lag effect for main girders with single box and triple cells through the curve of normal stress distributing and the curve of shear lag coefficient, and puts forward some suggestions for designing the same type main girders according to the features of the shear lag effect.