| 钢管混凝土节点承载力计算方法 |
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| 引用本文： | 姜磊,刘永健,周绪红,赵鑫东.钢管混凝土节点承载力计算方法[J].中国公路学报,2022,35(6):86-100. |
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| 作者姓名： | 姜磊 刘永健 周绪红 赵鑫东 |
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| 作者单位： | 1. 长安大学 公路学院, 陕西 西安 710064;2. 长安大学 公路大型结构安全教育部工程研究中心, 陕西 西安 710064;3. 重庆大学 土木工程学院, 重庆 400045 |
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| 基金项目： | 国家自然科学基金项目(52008026)；中国博士后科学基金项目(2021M692746)；陕西省自然科学基础研究计划项目(2021JQ-272)；中央高校基本科研业务费专项资金项目(300102211303，300102219310) |
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| 摘 要： | 钢管混凝土桁式结构广泛应用于桥梁工程中。为探明钢管混凝土节点的破坏机理,得到其承载力计算方法,系统汇总了国内外报道的圆形和矩形钢管混凝土节点试验数据,并根据节点形状和支管受力形式,分为139个受压节点、16个受拉节点和38个K型节点,分析主管内填混凝土对节点构造、破坏模式和承载力的改善,提出钢管混凝土节点设计流程和承载力计算方法。研究结果表明:在满足节点构造和焊接要求前提下,主管表面钢板层状撕裂破坏、焊缝破坏和受拉支管背面主管顶板局部屈曲破坏可以有效避免。对于受压节点,空钢管节点可能发生主管侧壁屈曲或表面屈服线破坏,而主管内填混凝土后,其破坏模式变为横向局部承压破坏,承载力平均提高8.3倍,不需要进行受压节点验算;对于受拉节点,管内混凝土能提高节点受拉刚度,破坏模式趋于主管表面冲剪破坏;对于K型节点,承载力以受拉支管控制,主要发生主管表面冲剪破坏,其强度与支管有效宽度破坏相当,即实现节点和钢管杆件等强设计,此外,考虑主管混凝土抗剪贡献后,主管抗剪承载力提高1.1~1.3倍;提出了钢管混凝土节点设计流程,并给出其节点承载力计算方法,圆形和矩形钢管混凝土节点均以受拉支管控制,需进行主管表面冲剪破坏和支管有效宽度破坏验算,同时,矩形钢管混凝土节点还需进行主管间隙处剪切破坏验算。
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| 关 键 词： | 桥梁工程 钢管混凝土节点 承载力 破坏模式 计算方法 |
| 收稿时间： | 2021-08-12 |
Calculation Method for the Bearing Capacity of Concrete-filled Steel Tube Joints |
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| JIANG Lei,LIU Yong-jian,ZHOU Xu-hong,ZHAO Xin-dong.Calculation Method for the Bearing Capacity of Concrete-filled Steel Tube Joints[J].China Journal of Highway and Transport,2022,35(6):86-100. |
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| Authors: | JIANG Lei LIU Yong-jian ZHOU Xu-hong ZHAO Xin-dong |
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| Affiliation: | 1. School of Highway, Chang'an University, Xi'an 710064, Shaanxi, China;2. Research Center of Highway Large Structure Engineering on Safety of Ministry of Education, Chang'an University, Xi'an 710064, Shaanxi, China;3. School of Civil Engineering, Chongqing University, Chongqing 400045, China |
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| Abstract: | Concrete-filled steel tube truss structures are widely used in bridge engineering. To understand the failure mechanism and calculation method for the bearing capacity of concrete-filled steel tube joints, the test data for circular and rectangular concrete-filled steel tube joints were summarized. It included 139 compressive joints, 16 tensile joints, and 38 K-joints, according to the shape and load state of the brace. The effects of the concrete infill on the geometric details, failure modes, and bearing capacities of the joint, were analyzed; and the design flow and bearing capacity formulae were proposed. The results show that the weld failure, lamellar tearing, and chord local buckling failure modes can be effectively avoided under the premise of meeting the geometric details and welding requirements. For the compressive joint, the failure mode changes from chord face plasticization failure and chord buckling to transverse local compression failure of the concrete-filled steel tube owing to the filling of the chord with concrete. The average increase in the bearing capacity is 8.3 times, thus, the strength verification for the compressive joints can be ignored. For the tensile joint, the concrete infill can improve the tensile stiffness of the joint, and the failure mode tends to be chord punching shear. For the K-joint, the bearing capacity was controlled by a tensile brace, and failure occurred via chord punching shear. The strength of the joint was approximately equal to the strength of the member, resulting in an optimum design. Moreover, the bearing capacity for chord shear failure improves by a factor of 1.1~1.3 times in consideration of the shear contribution of the concrete infill. The design flow and bearing capacity formulae for concrete-filled steel tube joints were proposed. The strengths of circular and rectangular concrete-filled steel tube joints were both controlled by a tensile brace, where the strength verification for chord punching shear failure and local yielding of the brace was carried out. Meanwhile, the strength verification for chord shear failure should be conducted for rectangular concrete-filled steel tube joints. |
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| Keywords: | bridge engineering concrete-filled steel tube joint bearing capacity failure mode calculation method |
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