钢格室顶板对斜拉桥结合段传力机理的影响研究

Research on Influence of Top Plates over Steel Latticed Chamber on Force Transfer Mechanism of Steel-Concrete Joint Section of Cable-Stayed Bridge

为了解钢格室顶板对混合梁斜拉桥钢-混结合段受力性能及传力机理的影响,以主跨530 m银洲湖特大桥为背景,采用Abaqus软件建立有、无顶板的钢-混结合段局部钢格室有限元模型,在与足尺模型试验结果进行对比验证模型准确性的基础上,分析2种钢格室模型各构件的受力分布及传力比,并研究了钢梁加劲段长度对钢格室受力性能的影响。结果表明:2种钢格室模型均处于明显的偏压受力状态,结构底板侧混凝土承担了大部分荷载作用;同一高度处的PBL连接件承担荷载高于栓钉连接件;7000 kN荷载作用下,去除钢格室顶板使连接件承担荷载比例提升约4%;结构极限承载力随钢梁加劲段长度的增加有所降低,但在相同荷载作用下,结合段连接件承担荷载比例几乎不变。

Based on the case of Yinzhou Lake Bridge that has a main span of 530 m,the influence of top plates over the steel latticed chamber on the force transfer mechanism of steel-concrete joint section of hybrid girder cable-stayed bridge is studied.The local finite element models of the steel latticed chamber with and without top plates in the steel-concrete joint section were established by Abaqus,and the calculation precision of which was verified by the full-scale model test.Subsequently,the force distribution in and load transfer ratio of each component of the two types of models were analyzed,and the influence of length of stiffened section of steel girder on the load bearing behavior of the steel latticed chamber was examined.It is shown that the two types of steel latticed chamber models are all under eccentric compression,where the base concrete slabs carry most of the loads.The PBL connectors bear more loads than the shear studs at the same elevation.With a specified load of 7000 kN,the load sharing ratio of each connector is improved by about 4%,when steel latticed chamber is equipped with no top plates.As the stiffening length of the steel girder increases,the ultimate load bearing capacity of the structure shows sign of slight drop.While under the same loads,the load sharing ratio of connectors in the steel-concrete joint section almost remains at a constant level.