有限梁段法在箱梁施工阶段剪力滞分析中的应用

摘要

In this paper,the finite segment method of warping displacement function based on the shear deformation law was used to analyze the shear lag effect of the box girder during construction.Based on the shear lag coefficient matrix and generalized load vector of corresponding girder element,the governing differential equations of shear lag and the corresponding boundary conditions were derived in this paper.Taking the prestressed concrete continuous box girder of a new railway from Guangzhou to Zhuhai as an example,the distribution of shear lag coefficient along the girder length was analyzed under three different load conditions in the cantilever construction of box girder bridge.The shear lag effect of the bridge in the operation stage was also analyzed under uniformly distributed load and mid-span concentrated load of the central span and compared with the variational analysis results.The results obtained in this paper agree well with the results obtained by the variational method,which validate the proposed method is accurate and reliable in the analysis of shear lag of box girder construction.%选取基于翼板剪切变形规律的翘曲位移函数有限梁段法来分析箱梁在施工过程中的剪力滞效应.通过剪力滞控制微分方程和边界条件推导了相应梁段单元剪力滞系数矩阵和广义荷载列阵.以广州至珠海新建铁路预应力混凝土连续箱梁为例,分析箱梁桥悬臂施工的3个阶段在不同荷载工况作用下剪力滞系数沿梁长的分布情况,以及在体系转换后成桥运营阶段,箱梁在均布荷载和中跨跨中集中荷载作用下的剪力滞效应,并与变分法分析结果进行对比.结果表明,采用本文方法计算得到的箱梁剪力滞系数与采用变分法所得结果吻合良好,验证了该方法用于箱梁施工过程中剪力滞分析的适用性.