摘要
按实际施工动态过程分析剪力滞对Π形结合梁斜拉桥中主梁弯曲刚度的影响。基于能量变分法引入简化的剪力滞翘曲位移函数,导出一种可以考虑剪力滞与Π形结合梁弯曲刚度耦合影响的实用梁单元。该方法每节点采用两个剪力滞自由度,可以处理斜拉桥中集中弯矩引起的剪力滞位移边界条件突变和施工动态过程中荷载和剪力滞位移边界条件不断变化的问题。结合某Π形结合梁斜拉桥进行数值分析并与实测数据比较,验证了本文方法的有效性与准确性。研究表明,剪力滞效应使斜拉桥中主梁的抗弯刚度减小,且在悬臂施工阶段比成桥阶段的影响更大;相对于简支箱梁和连续箱梁而言,剪力滞对Π形结合梁斜拉桥主梁弯曲刚度的影响相对小一些,在悬臂施工阶段其对中跨的影响约为2%~7%,对边跨的影响约为3%~12%。
The effect of shear lag on flexural stiffness of H-shaped composite girder in cable-stayed bridge was analyzed according to actual dynamic construction process. Based on variational principle, a practical beam element including the coupling of shear lag deformation and deflection of H-shaped composite girder was deduced by introducing a simplified shear lag warping displacement function. In this method, two shear lag degrees of freedom were employed at each node of the element, so that it could be treated that the sahation of boundary conditions for shear lag caused by concentrated bending moment in cable-stayed bridges, and the changes of loads and boundary conditions in dynamic construction process. Combined with a certain H-shaped composite girder cable-stayed bridge, the numerical analysis results were obtained, and were compared with measured data. It was shown that the presented method had good effectiveness and accuracy. It was also shown that the flexural stiffness of H-shaped composite girder in the cable-stayed bridge was decreased due to the shear lag effect, and that this effect is greater in cantilever construction stages than that in the last stage of construction. For the cable-stayed bridge concerned in the paper, the effect of shear lag on flexural stiffness of H-shaped composite girder in cantilever construction stages is about 2 ~ 7% for middle span and about 3 ~ 12% for side span, which is relatively smaller than that of simply-supported and continuous box girders.
出处
《土木工程学报》
EI
CSCD
北大核心
2018年第1期106-113,共8页
China Civil Engineering Journal
关键词
П形结合梁
剪力滞
有限梁段
弯曲刚度
斜拉桥
П-shaped composite girder
shear lag
finite segment method
flexural stiffness
cable-stayed bridge
