冲击荷载下钢筋混凝土缺口梁破坏模式的试验研究  

Tests for failure mode of RC notched beam under impact load

作　　者：宋敏 王志勇 张杰 高士武[2] 王志华 SONG Min;WANG Zhiyong;ZHANG Jie;GAO Shiwu;WANG Zhihua(Institute of Applied Mechanics,College of Mechanical and Vehicle Engineering,Taiyuan University of Technology,Taiyuan 030024,China;College of Civil Engineering,Qinghai University,Xining 810016,China)

机构地区：[1]太原理工大学机械与运载工程学院,应用力学研究所,太原030024 [2]青海大学土木工程学院,西宁810016

出　　处：《振动与冲击》2022年第13期126-134,共9页Journal of Vibration and Shock

基　　金：国家自然科学基金(11702186,12072217)。

摘　　要：钢筋混凝土梁在使用过程中内部的微裂缝和缺陷逐渐衍生扩展导致混凝土发生开裂。冲击荷载下钢筋混凝土缺口梁的承载性能和能量耗散与无缺口梁明显不同。为了合理评估钢筋混凝土缺口梁的抗冲击性能,利用落锤冲击试验机对不同配筋率的钢筋混凝土缺口梁进行了动态三点弯试验。通过对比分析冲击过程中锤头冲击力、支座反力和跨中位移,探讨了冲击速度对钢筋混凝土缺口梁破坏模式、承载力和能量耗散的影响。试验结果表明:钢筋混凝土缺口梁的破坏模式随着冲击速度和配筋率的增大由弯曲破坏逐渐转变为弯剪破坏;弯曲/弯剪破坏模式下支反力最大值和静态抗弯/抗剪承载力的比值与冲击速度呈线性增长关系;将支反力-跨中位移曲线简化为平行四边形后分别建立了静态抗弯/抗剪承载力与冲击速度的经验公式,为合理评估钢筋混凝土缺口梁的抗冲击性能提供参考依据。During use of reinforced concrete(RC)beam,its internal micro-cracks and defects gradually derive and expand to cause cracking of concrete.RC notched beam's load-bearing capacity and energy dissipation under impact load are obviously different from those of non-notched beam.Here,to reasonably evaluate anti-impact performance of RC notched beam,dynamic 3-point bending tests for RC notched beams with different reinforcement ratios were conducted using drop hammer impact testing machine.By contrastively analyzing impact force of hammer head,reaction force of support and midspan displacement in impact process,effects of impact velocity on failure mode,load-bearing capacity and energy dissipation of RC notched beam were explored.The test results showed that failure mode of RC notched beam gradually changes from bending failure to bending-shear failure with increase in impact velocity and reinforcement ratio;under bending or bending-shear failure mode,the ratio of the maximum support reaction force and static bending/shear load-bearing capacity increases linearly with increase in impact velocity;after simplifying reaction force-midspan displacement curve into a parallelogram,empirical formulas for static bending and shear load-bearing capacities and impact velocity were established,respectively to provide a reference basis for reasonably evaluating anti-impact performance of RC notched beam.

关 键 词：钢筋混凝土缺口梁 冲击速度 配筋率 破坏模式 承载力 能量耗散 

分 类 号：TH212[机械工程—机械制造及自动化] TH213.3