悬挑公路面公铁两用铆接钢桁梁桥次应力分析  

Secondary Stress Analysis of Riveted Steel Truss Rail⁃cum⁃Road Bridge with Cantilever Road Deck

作　　者：汪世龙 梁志广 张勇 胡强 WANG Shilong;LIANG Zhiguang;ZHANG Yong;HU Qiang(Tieke Inspection Co.Ltd.,Beijing 100081,China;Railway Engineering Research Institute,China Academy of Railway Sciences Corporation Limited,Beijing 100081,China)

机构地区：[1]铁科检测有限公司,北京100081 [2]中国铁道科学研究院集团有限公司铁道建筑研究所,北京100081

出　　处：《铁道建筑》2023年第4期38-41,共4页Railway Engineering

基　　金：中国铁道科学研究院集团有限公司基金(2022YJ174)。

摘　　要：钢桁梁设计中常将节点简化为完全铰接状态,但实际节点具有一定约束能力,在杆端会产生一定的次应力。本文以京九铁路赣江南桥悬挑公路面公铁两用的铆接钢桁梁桥为例,建立有限元模型,通过调整节点连接刚度(约束),分析次应力的变化对杆件受力的影响。有限元分析结果表明:随着节点刚度的增强,各杆件产生的轴向应力随之减小而次应力随之增大,在荷载作用下竖杆产生次应力,以面外弯曲应力为主,其余杆件则以面内弯曲应力为主。同时,荷载试验结果与有限元分析结果一致。虽然竖杆实测次应力系数较大,但考虑次应力系数后承载能力仍能满足设计要求。In the design of steel truss girders,the nodes are often simplified to a fully hinged state,but in reality,the nodes have a certain constraint capacity and will generate a certain amount of secondary stress at the member end.Taking the riveted steel truss rail-cum-road bridge with cantilever road deck of the Ganjiang South Bridge on the Beijing-Kowloon railway as an example,the influence of secondary stress changes on the force acting on the members was analyzed by establishing a finite element model and adjusting the node connection stiffness(constraint).The finite element analysis results show that as the node stiffness increases,the axial stress generated by each member decreases and the secondary stress increases.Under the action of load,secondary stress is generated in the vertical member,mainly due to out of plane bending stress,while the remaining members are mainly due to in plane bending stress.Meanwhile,the load test results are consistent with the finite element analysis results.Although the measured secondary stress coefficient of the vertical member is relatively large,the bearing capacity can still meet the design requirements after considering the secondary stress coefficient.

关 键 词：钢桁梁 次应力 数值模拟 静载试验 铰接 刚接 梁端刚域 

分 类 号：U448.121[建筑科学—桥梁与隧道工程]