落锤冲击作用下钢筋混凝土短梁响应及破坏试验研究  

Experimental Study on Response and Failure of Short Reinforced Concrete Beams under Impact Load by Drop Hammer

作　　者：杜宇翔 贾永胜 孙金山 姚颖康 谢全民 汪远远 聂森林 DU Yu-xiang;JIA Yong-sheng;SUN Jin-shan;YAO Ying-kang;XIE Quan-min;WANG Yuan-yuan;NIE Sen-lin(State Key Laboratory of Precision Blasting,Jianghan University,Wuhan 430056,China;b.Hubei Key Laboratory of Blasting Engineering,Jianghan University,Wuhan 430056,China;Hubei(Wuhan)Institute of Explosion Science and Blasting Technology,Jianghan University,Wuhan 430056,China;School of Digital Construction and Blasting Engineering,Jianghan University,Wuhan 430056,China)

机构地区：[1]江汉大学精细爆破国家重点实验室,武汉430056 [2]江汉大学爆破工程湖北省重点实验室,武汉430056 [3]江汉大学湖北(武汉)爆炸与爆破技术研究院,武汉430056 [4]江汉大学数字建造与爆破工程学院,武汉430056

出　　处：《爆破》2023年第4期115-123,共9页Blasting

基　　金：湖北省自然科学基金项目(2022CFB874,2020CFA043,2021CFB541);湖北省重点研发计划项目(2020BCA084);湖北省教育厅科学研究计划指导性项目(B2022282);国家自然科学基金项目(52209131);武汉市知识创新专项项目(2023020201020444)。

摘　　要：钢筋混凝土短梁是建构筑物的关键承力构件,为研究其在冲击荷载作用下的动力响应及破坏机制,结合应变式传感器、高速摄影、数字图像技术(DIC)等测量手段,开展了不同冲击体质量、冲击速度和冲击能量下的落锤冲击试验。结果表明:(1)冲击荷载作用下钢筋混凝土短梁破坏形式表现为拱形震坍裂缝和整体弯曲变形,与浅梁破坏形式有明显差异;(2)钢筋混凝土短梁跨中轴向应变由拉应变转为压应变,随着冲击能量增加(18061 J≤E≤49831 J),跨中轴向峰值拉应变、残余压应变均先增大后减小,钢筋混凝土短梁依次处于弹塑性挠曲变形、冲剪破坏模式阶段;(3)冲击荷载作用下钢筋混凝土短梁的裂缝萌生和扩展过程并不是单向的,裂缝多次多向扩展形成裂缝带,进而形成塑性铰,导致短梁整体破坏;(4)梁体变形程度主要取决于冲击速度而非冲击能量,具体表现相同冲击能量(30000 J)下,随着冲击速度增加(5.53 m/s≤v≤7.13 m/s),梁体跨中峰值挠度和残余挠度相应增大(26.81 mm≤w p≤29.85 mm;17.12 mm≤w r≤21.66 mm)。研究成果可为钢筋混凝土短梁的抗冲击性能设计、拆除爆破工程设计提供试验依据和机制认识。Reinforced concrete(RC)short beam is the key load-bearing component of buildings.In order to study its dynamic response and failure mechanism under impact load,drop hammer impact tests with different impact mass,impact velocity and impact energy were carried out by combining strain gauge sensor,high-speed photography and digital image technology(DIC).The results show that,the failure forms of the short RC beams under impact loads are arch collapse cracks and overall bending deformation,which are obviously different from those of shallow beams.The axial strain in the mid span of a short RC beam changes from tensile strain to compressive strain.With the increase of impact energy(18061 J≤E≤49831 J),the axial peak tensile strain and residual compressive strain in the mid span increase first and then decrease.The short RC beam is in the stage of elastic flexural deformation,elastic-plastic flexural deformation and punching shear failure mode in turn.The crack initiation and propagation process of the short RC beam under impact load is not unidirectional.And the fracture zone is formed by the multidirectional fracture propagation with multiple times,and then the plastic hinge is formed,resulting in the overall short beam failure.The deformation degree of the beam mainly depends on the impact speed rather than the impact energy.Specifically,the peak deflection and residual deflection in the middle span of the beam(26.81 mm≤w p≤29.85 mm;17.12 mm≤w r≤21.66 mm)increase with the increase of the impact speed(5.53 m/s≤v≤7.13 m/s)under the same impact energy(30000 J).

关 键 词：钢筋混凝土短梁 落锤冲击试验 冲击能量 动力响应 破坏机制 

分 类 号：TU375.1[建筑科学—结构工程]