A Research On The Shear Lag Effect Of Long Span Curve Bridges With High Pier

Based on theoretical analysis and finite element method analysis with the three span continues rigid frame bridges, the paper investigates the shear lag effect of box girder bridges with different cross sections. It concerns on calculating the shear lag coefficient of curve bridges with long span and high pier, through the plan member analyse and space solid analyse,the paper gets some useful conclusions which are different from the straight bridges under plain concrete dead load status. The paper studies the influence effect of the curve bridges with different curve radius, different ratio of width to span, different ratio of beam depth, different height of pier, different construction phase and the different cross section. The main conclusions are as follows:1 The space solid analyse can accurately reflect the stress of real structure of bridges, the curve bridge's shear lag effect of box girder can't be substituted by straight bridges and the shear lag effect can not be neglected.2 To the bridges with the radius larger than 250 meters, when the computing method is the plan member analyse the true stress of the structure may be 1.1-1.25 times to the calculated result.3 The shear lag effect of curve bridge is influenced by the curves radius, ratio of width to span, the girder depth, the construction phase and the different cross section position severely, but the influence of height of high pier is not large at all.4 The average normal stress of cross section is not changed much with the different curve radius, but the stress distribution of cross section is changed by the radius of curvature.The less the radius is the larger of the maximum stress is.