加载速率对CFRP加固混凝土梁断裂特性影响研究  

Influence of Loading Rate on the Fracture Characteristics of CFRP Reinforced Concrete Beams

作　　者：赵少伟 冯心淏 郭蓉 郭喜旺 ZHAO Shaowei;FENG Xinhao;GUO Rong;GUO Xiwang(College of Civil Engineering and Transportation,Hebei University of Technology,Tianjin 300401,China)

机构地区：[1]河北工业大学土木与交通学院,天津300401

出　　处：《防灾减灾工程学报》2024年第1期210-221,共12页Journal of Disaster Prevention and Mitigation Engineering

基　　金：国家自然科学基金项目(51878238)资助。

摘　　要：采用CFRP加固带裂缝混凝土梁,能明显提高构件的承载力和刚度,减小结构变形并延缓裂缝的扩展。由于混凝土材料本身和CFRP-混凝土界面的率敏感性,在动态加载速率下CFRP加固梁的断裂性能与准静态荷载下有着明显不同。为研究CFRP加固混凝土梁的动态力学性能,通过不同加载速率下三点弯曲梁断裂试验,对比分析了0.000 5、0.1、1、10 mm/s加载速率下CFRP加固预裂混凝土梁的断裂性能。结果表明:CFRP在混凝土梁裂缝扩展过程中承担着很强的阻裂作用和增强效果,与未加固混凝土梁相比,CFRP加固混凝土梁的极限荷载得到显著提高;随加载速率提高,混凝土梁固有的阻裂性能和断裂过程区骨料黏聚力的阻裂作用提高,混凝土梁断裂面骨料被拉断的数量增多,裂缝扩展路径更趋向平直;最后计算得到不同加载速率下CFRP加固混凝土梁裂缝扩展阻力曲线,分析了不同加载速率下CFRP加固混凝土梁裂缝扩展阻力曲线的变化规律。The use of CFRP to reinforce concrete beams with cracks can significantly improve the bearing capacity and stiffness of the members,reduce structural deformation and delay the expansion of cracks.Due to the rate sensitivity of the concrete material itself and the interface between CFRP and concrete,the fracture performance of CFRP-strengthened beams under dynamic loading rates is significantly different from that under quasi-static loading.In order to study the dynamic mechanical properties of concrete beams strengthened with CFRP,the fracture behavior of pre-cracked concrete beams strengthened with CFRP at different loading rates of 0.0005 mm/s,0.1 mm/s,1 mm/s and 10 mm/s was compared and analyzed through three-point bending fracture tests.The results show that CFRP plays a strong role in crack resistance and reinforcement during the process of crack propagation in concrete beams.Compared with unreinforced concrete beams,the ultimate load of CFRP rein-forced concrete beams is significantly improved;With the increase of loading rate,the inherent crack resistance of concrete beams and the crack resistance of aggregate cohesion in the fracture path in-crease,the number of broken aggregates at the fracture surface of concrete beams increases,and the crack propagation path tends to be more straight;Finally,the crack propagation resistance curves of CFRP-concrete beams under different loading rates were calculated,and the variation law of crack propagation resistance curves of CFRP-reinforced concrete beams under different loading rates was discussed.

关 键 词：断裂性能 加载速率 CFRP加固混凝土 裂缝扩展阻力曲线 

分 类 号：TU528[建筑科学—建筑技术科学]