摘要
矩形空心墩因截面挖空导致抗剪性能削弱,塑性铰区弯剪裂缝显著,而既有等效塑性铰模型和等效塑性铰长度公式较少涉及弯剪耦合变形。为此,文章提出考虑弯矩梯度、拉伸漂移、应变渗透效应以及剪切变形的矩形空心墩曲率分布假定和墩顶位移计算方法,基于墩底塑性转角相等原则推导包含弯矩梯度、拉伸漂移和应变渗透效应的等效塑性铰长度理论公式和经验公式,并通过64个矩形空心墩试验数据对上述公式进行标定和验证。结果表明:规准等效塑性铰长度(L_(p)/h)随剪跨比、纵筋率及材料特性参数(f_(ul)/f_(yl)、f_(y1)d_(b)/√f'_(c))的增加而增大,与建议等效塑性铰长度经验公式的预测一致;规范和王震公式均高估了扣除剪切位移后的等效塑性铰长度,且会高估墩顶极限位移能力,使抗震设计偏于不安全;Berry公式计算的等效塑性铰长度略微保守,且能较准确地预测矩形空心墩的极限位移;而基于建议等效塑性铰长度经验公式和剪切位移占比系数经验公式的等效塑性铰模型,对矩形空心墩位移能力评估具有较高的计算精度和更小的离散性。
The shear capacity of rectangular hollow pier is weakened due to the section excavation,resulting in obvious flexure-shear cracks in plastic hinge region.However,existing equivalent plastic hinge models and equivalent plastic hinge length formulas rarely involve flexure-shear interaction(FSI)deformation.Thus,thecurvaturedistribution assumption and the calculation method of top displacement are proposed with consideration of the effects of moment gradient,tension shift,and strain penetration,together with the shear deformation.Theoretical formula and empirical expression of equivalent plastic hinge length considering the effects of moment gradient,tension shift,and strain penetration is derived based on the equation of bottom plastic rotation.The above formulas are calibrated and validated using the experimental data of 64 rectangular hollow piers.The results show that the normalized equivalent plastic hinge length(L_(p)/h)increases with the shear span ratio,longitudinal rebar ratio,and material characteristic parameters(f_(ul)/f_(yl) and f_(y1)d_(b)/√f'_(c)),which is consistent with the prediction of the proposed empirical formula of equivalent plastic hinge length.Formulas from codes and Wang Zhen overestimate the equivalent plastic hinge length deducting the shear deformation and overestimates the ultimate top displacement,resulting in less security for seismic design.Berry formula produces slightly conservative equivalent plastic hinge length and predicts the ultimate displacement of rectangular hollow piers accurately.The equivalent plastic hinge model,using the proposed empirical formulas of equivalent plastic hinge length and shear displacement proportion coefficient,has high calculation accuracy and smaller dispersion for displacement assessment of rectangular hollow piers.
作者
漆启明
邵长江
杨华平
庄卫林
崔皓蒙
王春阳
Qi Qiming;Shao Changjiang;Yang Huaping;Zhuang Weilin;Cui Haomeng;Wang Chumyang(Chengdu University,Chengdu 610106,China;School of Ciwil Engineering,Southwest Jiaotong University,Chengdu 610031,China;National Engineering Research Center for Geological Disaster Prevention Technology in Land Transportation,Southuest Jiaotong University,Chengdu 610031,China)
出处
《土木工程学报》
EI
CSCD
北大核心
2024年第11期23-32,105,共11页
China Civil Engineering Journal
基金
国家自然科学基金(51978581,51178395)
四川省应用基础研究重点项目(2017JY0059)。
关键词
桥梁工程
矩形空心墩
等效塑性铰模型
等效塑性铰长度
弯剪耦合变形
极限位移能力
bridge engineering
rectangular hollow pier
equivalent plastic hinge model
equivalent plastic hinge length
flexure-shear interaction(FSI)deformation
ultimate displacement capacity
作者简介
漆启明(1993-),男,博士,讲师。主要从事桥梁工程抗震研究;通讯作者:邵长江(1970-),男,博士,教授。主要从事桥梁工程抗震研究;杨华平(1989-),男,博士,副教授。主要从事桥梁工程抗震研究;庄卫林(1966-),男,硕士,教授。主要从事桥梁设计、咨询和交通防灾研究;崔皓蒙(1998-),男,博士研究生。主要从事桥梁工程抗震研究;王春阳(1997-),男,博士研究生。主要从事桥梁工程抗震研究。
