关键词: 桥梁工程, 箱桁组合钢梁, 剪力滞效应, 横隔板间距, 桥面板厚度, 截面高度

Abstract: To analyze the shear lag effect of the overall box girder bridge deck, a finite element model of overall steel box-truss composite girder was established, which took a long span rail-cum-road cable stayed bridge in the construction as the research object. The influence rule of the transverse diaphragm distance, bridge deck thickness and cross-section height on the shear lag effect was also studied. The research results show that there are shear lag phenomena in the steel box-truss composite girder. Due to the low stress level and the bearing stress complexity, shear lag phenomena are more evident in the side span than in other areas. The uneven coefficient of maximum stress is 9.27 at the point of transition pier. The shear lag effect of most segments of middle span is small; the uneven coefficient of stress is 1.06 at top plate of and 1.09 at bottom plate; the stress uniformity of the top plate is higher than that of the bottom plate. The uneven coefficient gradually decreases from the middle section of middle span to the section near the tower. The stress uneven coefficient of top and bottom plates decreases with the increase of transverse diaphragm distance, bridge deck thickness and cross-section height, meanwhile its decreasing range is less than 5%.

Key words: bridge engineering, steel box-truss composite girder, shear lag effect, transverse diaphragm distance, bridge deck thickness, cross-section height