半穿式应急钢桁梁上弦杆面外屈曲临界力研究  

Out of plane buckling critical force of upper chord of a semi-through emergency steel truss beam

作　　者：赵曼 陈士通[2,3,4] 孙志星[2,3,4] 许宏伟 黄晓明[5] ZHAO Man;CHEN Shitong;SUN Zhixing;XU Hongwei;HUANG Xiaoming(School of Civil Engineering,Shijiazhuang Tiedao University,Shijiazhuang 050043,China;State Key Lab of Mechanical Behavior and System Safety of Traffic Engineering Structures,Shijiazhuang Tiedao University,Shijiazhuang 050043,China;Collaborative Innovation Center for Performance and Security of Large-scale Infrastructure,Shijiazhuang Tiedao University,Shijiazhuang 050043,China;Hebei Provincial Eng.Research Center for Traffic Emergency and Guarantee,Shijiazhuang Tiedao University,Shijiazhuang,050043,China;School of Transportation,Southeast University,Nanjing 210096,China)

机构地区：[1]石家庄铁道大学土木工程学院,石家庄050043 [2]石家庄铁道大学省部共建交通工程结构力学行为与系统安全国家重点实验室,石家庄050043 [3]石家庄铁道大学大型基础设施性能与安全省部共建协同创新中心,石家庄050043 [4]石家庄铁道大学河北省交通应急保障工程技术研究中心,石家庄050043 [5]东南大学交通学院,南京210096

出　　处：《振动与冲击》2023年第17期96-104,共9页Journal of Vibration and Shock

基　　金：国家重点研发计划(2021YFB2600605,2021YFB2600601,2021YFB2600600)。

摘　　要：根据半穿式应急钢桁梁的结构特点和屈曲特征,将其上弦杆简化为侧向弹性支撑下的连续梁,考虑轴力分布、支撑条件及挠曲线形式建立四种平面模型,采用能量法推导其面外屈曲临界力解析解,并建立不同跨径半穿式应急钢桁梁整体模型,通过理论结果与仿真结果的对比分析,探讨各平面模型的优缺点及其适用性,旨在提出便于工程应用的屈曲临界力计算方法。研究结果表明:四种平面模型的稳定方程和屈曲临界力解析解形式各不相同;基于给出的临界刚度计算公式,结合实际支撑刚度和临界刚度的关系,可初步确定屈曲半波数;半穿式应急钢桁梁稳定性与跨径密切相关,线弹性稳定系数随跨径增大逐渐减小,且屈曲模态半波数有所增加,但失稳时上弦杆最大轴力基本保持不变;相比整体模型和文献算法,模型Ⅰ、Ⅱ结果过于保守不宜直接采用,模型Ⅲ、Ⅳ计算误差较小,由于模型Ⅳ计算过程繁复,而模型Ⅲ简单实用,综合考虑准确度和实用性,建议采用模型Ⅲ作为屈曲临界力计算的首选方法。Here,based on structural characteristics and buckling features of a semi-through emergency steel truss beam,its upper chord was simplified as a continuous beam under lateral elastic supports.4 plane models were established considering axial force distribution,support conditions and deflection curve forms.The energy method was used to derive the analytical solution to its critical force for out of plane buckling,and overall models of semi-through emergency steel truss beam with different spans were established.The theoretical results and simulation results were contrastively analyzed to explore advantages,disadvantages,and applicability of each plane model for the purpose of proposing a buckling critical force calculation method to be convenient for engineering applications.The study results showed that stability equations and buckling critical force analytical solutions of the 4 plane models are different in form;based on the given critical stiffness calculation formula,combined with the relation between actual support stiffness and critical stiffness,buckling half wave number can be preliminarily determined;the stability of semi-through emergency steel truss beam is closely related to span,its linear elastic stability coefficient gradually decreases with increase in span,and half wave numbers of buckling modes increase,but the maximum axial force of upper chord remains basically unchanged when unstable;compared to the overall model and algorithms in literature,the results of model I and model II are too conservative to directly use,the calculation errors of model III and model IV are smaller,due to the calculation process of model IV being heavy and complicated,while model III is simple and practical,comprehensively considering the correctness and practicality,it is recommended to take model III as the preferred method for calculating buckling critical force.

关 键 词：桥梁工程 半穿式钢桁梁 屈曲临界力 能量法 面外屈曲 平面模型 

分 类 号：U448.22[建筑科学—桥梁与隧道工程]