钢管混凝土相贯焊接节点受力分析与疲劳寿命研究  

Research on Mechanical Property and Fatigue Life of Tubular Intersecting Welded Joints of Concrete-Filled Steel Tubes

作　　者：康玲 牟廷敏 闫忠 KANG Ling;MOU Tingmin;YAN Zhong(Sichuan Highway Planning,Survey,Design and Research Institute Ltd.,Chengdu 610041,China;Sichuan Jiuma Expressway Co.,Ltd.,Aba 624699,China)

机构地区：[1]四川省公路规划勘察设计研究院有限公司,四川成都610041 [2]四川久马高速公路有限责任公司,四川阿坝624699

出　　处：《世界桥梁》2023年第6期69-75,共7页World Bridges

基　　金：国家自然科学基金区域创新发展联合基金重点项目(U21A20149);四川省交通运输科技项目(2016B2-1-1);四川省交通科技项目(2021-C-01)。

摘　　要：为研究钢管混凝土相贯焊接节点在轴力和弯矩共同作用下,管内混凝土对节点疲劳寿命的贡献,制作钢管混凝土桁梁桥K型相贯焊接节点1∶2缩尺模型并建立实体有限元模型,开展空管、仅弦管灌注混凝土、弦管和腹管均灌注混凝土3类构件相贯焊接节点受力分析与疲劳试验验证。结果表明:弦管与腹管灌注混凝土可提高结构刚度和调整结构内力,中弦管到边弦管的传力路径由单一的斜腹管变为斜腹管与水平腹管共同传力,斜腹管内力由轴力变为轴力与弯矩的组合形式。疲劳试验测得的相贯焊接节点最大应力位置、大小及应力分布状态与有限元计算结果吻合。弦管与腹管灌注混凝土使相贯焊接节点整体应力及峰值应力均降低,改善了相贯焊接节点的应力分布状态,延缓了裂纹发展速度,延长了相贯焊接节点疲劳寿命。The study in this paper focuses on the contribution of in-fill concrete to the fatigue life of tubular intersecting welded joints(TIWJs)in the concrete-filled steel tubes under the interaction of axial forces and bending moments.Specimens of 1∶2 scale of the K-shaped TIWJs of the concrete-filled steel tubular truss bridge were prepared and solid-element numerical models were developed to analyze the load bearing behaviors and fatigue life of TIWJs in three types of specimens,including the specimens consisting of empty braces and chords,specimens containing empty braces and concrete-filled chords,and specimens consisting of concrete-filled braces and chords.It is shown that the specimens with concrete-filled braces and chords have improved structural stiffness and internal forces,where the load transfer between the center chord to side chord is changed from depending on pure oblique braces to shared load transfer of oblique and horizontal braces.The internal force of oblique braces transforms from axial force to the combined force of axial force and bending moment.The maximum stress locations,stress values and distribution of TIWJs obtained by fatigue test agree with the finite element calculations.When both the braces and chords are filled with concrete,the overall stress and peak stress in a TIWJ are reduced,leading to improved stress distribution in the TIWJ,slow growth of cracks and longer fatigue life of the intersecting welded joint.

关 键 词：桥梁工程 钢管混凝土结构 相贯焊接节点 缩尺模型 应力分布 疲劳试验 有限元法 

分 类 号：U441[建筑科学—桥梁与隧道工程]