大跨公铁同层斜拉桥超宽幅钢箱梁剪力滞效应  

Shear Lag Effect of Ultra-wide Steel Box Girder of Large-span Road-rail Cable-stayed Bridge

作　　者：韩冰 卫星[2] 张伟勇[1] 陈杨 汪蓉蓉 HAN Bin;WEI Xing;ZHANG Weiyong;CHEN Yang;WANG Rongrong(Southern Sichuan Intercity Railway Co.,Ltd.,Zigong 643002,China;Department of Bridge Engineering,School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;CCCC Highway Consultants Co.,Ltd.,Beijing 100010,China)

机构地区：[1]川南城际铁路有限责任公司,四川自贡643002 [2]西南交通大学土木学院桥梁工程系,成都610031 [3]中交公路规划设计院有限公司,北京100010

出　　处：《铁道标准设计》2022年第11期82-87,113,共7页Railway Standard Design

基　　金：国家自然科学基金项目(52078424);四川省铁路产业投资集团科技项目(SRIG2019FW0001)。

摘　　要：超宽幅钢箱梁高宽比较小,竖向荷载作用下超宽幅钢箱梁处于双向受弯状态,其受力特征不同于常规钢箱梁。为研究正弯矩作用下超宽幅钢箱梁剪力滞效应引起的纵桥向正应力非均匀分布特征,以宜宾临港长江大桥为工程背景,利用ANSYS建立超宽幅钢箱梁跨中梁段空间有限元模型;考虑7种典型荷载工况,计算得到不同荷载工况下超宽幅钢箱梁顶板及底板纵向剪力滞系数分布;并研究不同横隔板间距及斜拉索索距对超宽幅钢箱梁顶板及底板纵向剪力滞系数的影响。研究结果表明:(1)超宽幅钢箱梁在不同荷载作用下,结构受力存在明显的空间受力特征,双向弯曲,约束扭转、剪力滞后等力学行为值得关注;(2)正弯矩作用下顶板纵向正应力受正剪力滞效应影响,底板纵向正应力受负剪力滞影响;(3)适当增加横隔板间距及减小斜拉索索距可降低剪力滞效应;(4)超宽幅钢箱梁设计时应进行精细化分析,以明确结构空间受力特征。The ratio of height to width of the ultra-wide steel box girder is relatively small.Under vertical load,the ultra-wide steel box girder is in a bidirectional bending state,and its behavior is different from conventional steel box girder.To study the longitudinal normal stress distribution characteristics of the ultra-wide steel box girder caused by the shear lag effect under positive bending moment,a 3D finite element model of the mid-span section of the box girder is established by using ANSYS with reference to the Yibin Lingang Yangtze River Bridge.Considering 7 typical load cases,the longitudinal shear lag coefficient distributions of the top and bottom plates of the ultra-wide steel box girder under different load conditions are obtained.The influences of the distance between the diaphragms and the distance of stay cables on the shear lag coefficient of the top and bottom plates of the ultra-wide steel box girder are investigated.The results show that:(1)The ultra-wide steel box girder structure has obvious spatial mechanical behavior,and the behaviors such as bidirectional bending,constrained torsion,and shear lag are worthy of attention;(2)The longitudinal normal stress of the top plate is affected by the positive shear lag effect,and the longitudinal normal stress of the bottom plate is affected by the negative shear lag;(3)Appropriately increasing the distance between the diaphragms and reducing the cable distance can reduce the shear lag effect;(4)Fine analysis of the ultra-wide steel boxgirder should be taken to define the spatial mechanical behavior of structure.

关 键 词：公铁斜拉桥 超宽钢箱梁 剪力滞效应 有限元分析 有效分布宽度 

分 类 号：U448.27[建筑科学—桥梁与隧道工程] U441.4[交通运输工程—道路与铁道工程]