考虑截面配筋的箱梁剪力滞效应分析

Analysis of the Shear Lag Effect in Consideration of Section Reinforcement

为研究截面配筋后的箱梁剪力滞效应,采用能量变分法,建立箱梁剪力滞效应的分析方程,并推导出简支梁在集中荷载和均布荷载作用下考虑剪力滞效应的附加弯矩和挠度计算公式。结合铁路标准设计箱梁算例,分析了不同配筋率时的箱梁剪力滞效应。结果表明,截面配筋对箱梁剪力滞效应有一定的影响,随截面配筋率增大,截面剪力滞附加弯矩增大,挠度减小,剪力滞效应突出。对算例箱梁,考虑截面配筋后剪力滞附加弯矩增大可达298.37%,挠度减小可达15.98%,剪力滞系数增大可达1.36%。

In order to study the shear lag effect of box girder with section reinforcement,the analytical equation of the shear lag effect of box girder was established using the energy variation method to derive the formulas for calculating additional moment and deflection of simply supported beam considering the shear lag effect under concentrated load and uniform load.The shear lag effect of box girder with different reinforcement ratios was calculated and analyzed through the standard design of railway box girder.The results show that section reinforcement has certain influence on the shear lag effect of box girder.With the increase of the section reinforcement ratio,the additional bending moment of the section shear lag effect increases,while the deflection decreases and the shear lag effect becomes prominent.In the case of box girder,the additional bending moment of the shear lag effect can increase by 298.37% after considering section reinforcement while the deflection can decrease by 15.98% and the maximum increase of shear lag coefficient is 1.36%.