侧向冲击与静力加载下小剪跨比RC柱的剪切损伤行为  

Shear Damage Behavior of RC Columns with Small Shear-to-span Ratios Under Lateral Impact and Static Loa

作　　者：陈林[1,2] 周戴江 冯非凡 刘涛 吴冲 CHEN Lin;ZHOU Dai-jiang;FENG Fei-fan;LIU Tao;WU Chong(School of Civil Engineering,Hunan University of Science and Technology,Xiangtan 411201,Hunan,China;Hunan Provincial Key Laboratory of Structural Engineering for Wind Resistant and Vibration Control,Hunan University of Science and Technology,Xiangtan 41120l,Hunan,China)

机构地区：[1]湖南科技大学土木工程学院,湖南湘潭411201 [2]湖南科技大学结构抗风与振动控制湖南省重点实验室,湖南有湘潭411201

出　　处：《中国公路学报》2024年第5期211-221,共11页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(52278500);湖南省教育厅重点项目(21A0293)。

摘　　要：为深入研究小剪跨比条件下钢筋混凝土(RC)柱的抗冲击性能与剪切损伤行为,分别开展了6根RC柱的侧向摆锤冲击试验和8根RC柱的水平静力加载试验,考察了剪跨比、纵筋和箍筋用量以及轴压力等参数对试件抗剪性能的影响,并对冲击作用下各试件的剪切损伤和弯曲损伤进行了等级划分。试验结果表明:动、静力作用下小剪跨比RC柱均易发生剪切破坏,箍筋对柱体抗变形能力和静态剪切承载力有较大贡献,但对冲击作用下试件剪切承载力的贡献较小;随着冲击能量的增大,柱身首次出现的斜裂缝与水平方向的夹角变小,而二次冲击下试件破坏形态受初次冲击损伤状态的影响较大;静力试验中,轴压力的增大延缓了试件前期弯曲和剪切损伤的发展,并提升试件承载能力,但会显著降低具有极小剪跨比(例如等于1.4)试件的延性。在试验基础上,采用冲击力峰值与试件剪切承载力(动态或静态)的比值作为损伤评估指标,对冲击作用下RC柱的剪切损伤状态进行了评估。分析结果表明:已有动态剪切承载力计算方法未能充分考虑不同剪跨比和柱体边界条件引起的惯性效应的差别,而试验所得静态剪切承载力也不能有效地反映动态剪切承载力随剪跨比变化的规律,因此目前采用冲击力峰值与剪切承载力的比值来对剪跨比存在变化的RC柱进行剪切损伤评估还存在困难。To investigate the impact resistance and shear damage behavior of reinforced concrete(RC)columns with small shear-to-span ratios,lateral pendulum impact tests and horizontal static loading tests were conducted on six and eight RC columns,respectively.The tests examined the effects of the shear-to-span ratios,amount of longitudinal rebars and stirrups,and axial compression force on the shear performance of the specimens;and the shear and bending damage of the specimens under impact loads were classified.The test results showed that RC columns with small shear-to-span ratios were prone to shear failure under both dynamic and static loads.Stirrups significantly contributed to the deformation capacity and static shear capacity of the columns but did not affect the shear capacity of the specimens under impact loads significantly.With an increase in the impact energy,the angle between the first diagonal crack and horizontal direction became smaller,and the failure mode of the specimen under the second impact was strongly affected by the damage sustained after the first impact.In the static loading tests,the increase in the axial compression force delayed the bending and shear damage of the specimens in the early stages and enhanced their load-carrying capacity.However,it significantly reduced the ductility of the specimens with very small shear-to-span ratios(e.g.,equal to 1.4).Based on the tests,the ratio of the peak impact force to the shear capacity(dynamic or static)of the specimens was used as a damage index to evaluate the shear damage status of the specimens under impact loads.The analysis results show that the existing dynamic shear capacity calculation method fails to fully consider the difference in inertial effects caused by different shear-to-span ratios and column boundary conditions,and the static shear capacity obtained from the tests cannot effectively reflect the change rule of the dynamic shear capacity with the shear-to-span ratio.Therefore,it is difficult to adopt the ratio of the peak impact force

关 键 词：桥梁工程 RC柱 冲击试验 剪切损伤 小剪跨比 

分 类 号：U443.22[建筑科学—桥梁与隧道工程]