钢管混凝土KK型节点疲劳性能试验  

Fatigue performance experiment of concrete-filled steel tubular-KK joint

作　　者：吴庆雄[1,2] 罗健平 杨益伦 陈康明[1,3] 缪承谕 中村聖三 WU Qing-xiong;LUO Jian-ping;YANG Yi-lun;CHEN Kang-ming;MIAO Cheng-yu;NAKAMURA Shozo(College of Civil Engineering,Fuzhou University,Fuzhou 350116,Fujian,China;Fujian Provincial Key Laboratory on Multi-Disasters Prevention and Mitigation in Civil Engineering,Fuzhou University,Fuzhou 350l16,Fujian,China;Key Laboratory of Fujian Universities for Engineering Structures,Fuzhou University,Fuzhou 350116,Fujian,China;School of Engineering,Nagasaki University,Nagasaki 852-8521,Nagasaki,Japan)

机构地区：[1]福州大学土木工程学院,福建福州350116 [2]福州大学福建省土木工程多灾害防治重点实验室,福建福州350116 [3]福州大学福建省高校工程结构重点实验室,福建福州350116 [4]长崎大学工学部,长崎长崎852-8521

出　　处：《交通运输工程学报》2024年第1期100-116,共17页Journal of Traffic and Transportation Engineering

基　　金：国家自然科学基金项目(52078137,51678154)。

摘　　要：为研究钢管混凝土KK(CFST-KK)型节点疲劳性能,开展了CFST-KK型节点模型疲劳试验,分析了CFST-KK型节点热点应力分布规律和疲劳性能演化过程;建立了CFST-KK型节点实体有限元模型,结合试验和有限元结果,分析了CFST-KK型节点与钢管混凝土K(CFST-K)型节点疲劳性能的差异性;研究了不同参数对KK型节点疲劳性能影响,探讨了适用于CFST-KK型节点疲劳寿命的评价方法。研究结果表明:采用二次外推方式计算的CFST-KK型节点,最大热点应力位于受拉支管相贯焊缝的主管侧冠点偏外鞍点15°处;计算CFST-KK型节点应力集中系数时,支管名义应力可仅考虑轴力和面内弯矩的影响而不考虑面外弯矩的影响,其应力集中系数为6.36,比CFST-K型节点大80.2%;CFST-KK型节点的疲劳裂纹萌生于最大热点应力处,在反复加载过程中裂纹沿焊趾根部向两侧与主管壁厚方向延伸,裂纹向外鞍点扩展的速度要略快于向内鞍点扩展的速度,停止反复加载后裂纹并未贯穿主管管壁;受支管面外弯矩与支管间空间效应的影响,CFST-KK型节点的抗疲劳性能与CFST-K型节点有明显差异;主管内填混凝土能提升CFST-KK型节点径向刚度,缓解应力集中情况;支管面外夹角增大会增大支管间空间效应的影响;考虑钢管内混凝土影响的CFST-K型节点的热力应力与疲劳寿命曲线在评价CFST-KK型节点疲劳寿命时具有良好的精度。In order to study the fatigue performance of concrete-filled steel tubular-KK(CFSTKK)joint,a fatigue test on CFST-KK joint models was conducted,and the stress distribution pattern and fatigue performance evolution of CFST-KK joints were analyzed.A solid finite element(FE)model of CFST-KK joint was established.In combination with the results of the test and FE models,the difference in the fatigue performance between the CFST-KK joint and the concrete-filled steel tubular-K(CFST-K)joint was revealed,the influences of different parameters on the fatigue performance of KK joint were analyzed,and an appropriate fatigue life evaluation method for the CFST-KK joint was discussed.Research results show that the maximum hot spot stress of CFST-KK joint calculated by the quadratic extrapolation method is located 15°away from the crown point on the chord side of tension brace to the chord intersecting weld towards the outer saddle point.In calculating the stress concentration factor(SCF)of CFST-KK joint,the nominal stress of the brace only takes into account the influence of axial force and in-plane bending moment regardless of the impact of out-of-plane bending moment,and the SCF of CFST-KK joint is 6.36,80.2%higher than that of CFST-K joint.The fatigue crack in the CFST-K joint originates at the location with the highest stress concentration,extends towards the two sides and wall thickness of the chord along the weld toe root during repeated loading,and expands slightly faster towards the outer saddle point than the inner saddle point.However,it does not penetrate the chord wall after stopping the repeated loading.The fatigue resistance of CFST-KK joint differs significantly from that of CFST-K joint,primarily due to the presence of out-of-plane bending moment in the brace and the spatial interaction between the braces.Filling the tube with concrete can enhance the radial stiffness of CFST-KK joint and reduce the stress concentration.Augmenting the angle beyond the branch face can enhance the spatial interaction between t

关 键 词：桥梁工程 钢管混凝土KK型节点 疲劳性能试验 热点应力 应力集中系数 疲劳寿命 

分 类 号：U441.4[建筑科学—桥梁与隧道工程]