螺旋箍筋 [矩形空心墩变形能力及塑性铰区约束箍筋用量]

　　作者简介：孙治国（1980），男，博士生，主要从事桥梁与结构工程抗震研究，(Email)szg_1999_1999@163.com。　　王东升（通信作者），男，教授，博士生导师，(Email)dswang@dlmu.edu.cn。摘要：为研究空心截面桥墩的变形能力和塑性铰区约束箍筋用量，整理了71个矩形空心墩的抗震拟静力试验数据，总结了不同破坏形态下空心墩的变形能力和现有规范对保证空心墩延性抗震能力的可靠性，基于多元线性回归分析和相关分析讨论了影响空心墩变形能力的主要因素，基于Caltrans规范给出了矩形空心墩塑性铰区约束箍筋用量计算公式。研究发现：Caltrans规范和ACI规范对保证矩形空心墩的弯曲破坏形态和延性变形能力具有较高的可靠性，中国JTG/T B02-01—2008规范偏于不安全。矩形空心墩变形能力主要与塑性铰区配箍、纵筋配筋、壁厚和轴压比等因素有关，随箍筋、纵筋配筋和壁厚增加而增加，随轴压比增加而减少。
　　关键词：混凝土桥梁；钢筋混凝土矩形空心墩；变形；约束箍筋；延性；极限位移角
　　中图分类号：U443.22文献标志码：A文章编号：16744764（2012）03009508
　　Deformation Capacity and Amount of Confining Reinforcement in
　　Potential Plastic Hinge Regions of Rectangular Hollow Bridge Piers
　　SUN Zhiguo1, WANG Dongsheng1, GUO Xun2, LIANG Yongduo2
　　(1. Institute of Road and Bridge Engineering, Dalian Maritime University, Dalian 116026, Liaoning, P. R. China;
　　2. Institute of Engineering Mechanics, China Earthquake Administration, Harbin 150080, P. R. China)
　　Abstract:Quasistatic test results of 71 rectangular hollow bridge piers were collected to study the deformation capacity and amount of confining reinforcement in the potential plastic hinge region of the bridge piers. The deformation capacity of the hollow bridge piers with different failure modes were analyzed, and current codes provisions for the amount of confining reinforcement in hollow bridge piers were evaluated. Then, main factors influencing the deformation capacity of the piers were discussed based on multiple linear regression analysis and correlation analysis. At last, design equations based on Caltrans code of required confining reinforcement for rectangular hollow bridge piers were proposed. It is found that both the Caltrans and ACI codes show great reliability for the flexural failure mode and deformation capacity of the hollow bridge piers while the Chinese JTG/T B02-01-2008 code is unsafe. Also, the deformation capacity of the hollow bridge piers increases with the increase of the transverse reinforcement, longitudinal reinforcement, and web width, and decreases with the increase of the axial load ratio.
　　Key words:concrete bridges; reinforced concrete rectangular hollow bridge piers; deformation; confining reinforcement; ductility; ultimate drift ratio
　　中国已建和在建的众多大型桥梁工程中，空心截面桥墩占有相当大的比重，且较多位于高地震烈度区［13］，而目前尚缺乏桥梁高墩(空心墩)的震害经验，对其抗震能力认识不足，开展空心墩抗震性能的研究，对保证交通生命线安全，具有极为重要的意义。
　　钢筋混凝土空心墩抗震性能研究的开创性工作是由著名结构抗震专家Park等［4］在新西兰领导完成的，他们通过4个矩形空心墩的抗震拟静力试验，发现塑性铰区配箍满足Caltrans规范［5］要求的试件表现出良好的延性和耗能能力［6］。Pinto等［7］、Calvi等［8］、Delgado等［9］以欧洲典型的未经抗震设计桥梁为原型，进行了一系列空心墩的抗震试验，旨在研究旧有桥梁的抗震薄弱环节，探讨空心墩抗震数值分析技术及抗震加固策略。日本学者Takahashi等［10］通过矩形空心墩的抗震试验，强调了空心墩的抗剪薄弱性和合理估计其剪切变形的重要性。中国台湾学者和美国学者结合岛内高速铁路计划，对空心墩的抗震能力进行了系统研究［1116］。与此同时，中国宋晓东［17］、刘林［18］、郝文秀等［19］、崔海琴等［2021］、宗周红等［22］、孙治国等［23］也进行了一系列的空心墩抗震试验研究。〖=D(〗孙治国，等：矩形空心墩变形能力及塑性铰区约束箍筋用量〖=〗