摘要
碳纤维薄板(CFL)与混凝土粘结界面的疲劳性能是CFL加固RC梁关键的力学问题之一。应用疲劳与断裂力学方法给出了受弯CFL加固RC梁界面疲劳裂缝尖端的应力强度因子计算方法,并结合理论推导与一系列的疲劳实验研究,对加固梁中CFL与混凝土界面疲劳裂缝扩展的规律和预测方法进行了分析。结果表明:1)CFL的应变值与界面裂缝的应力强度因子的大小成正比,是界面疲劳裂缝扩展寿命的决定因素。当CFL的应变值小于疲劳破坏门槛值时,界面疲劳裂缝不会发生扩展;2)界面裂缝扩展主要分为萌生、稳定扩展、失稳扩展三个阶段。受弯CFL加固RC梁的界面疲劳裂缝的扩展寿命可以用类似于Paris公式的方法较准确地预测。
One of the key mechanical problems of strengthening RC beams with carbon fiber laminate （CFL） is the CFL-concrete interfacial fatigue properties. Fatigue and fracture mechanics method is used to develop a calculation formula of stress intensity factor （SIF） for the interfacial fatigue cracks. Based on theoretic analysis and a serial of fatigue tests, the propagation law and the predicting method of the interfacial fatigue cracks are discussed. The main results show that： 1） the SIF＇s value, a determined factor of the fatigue crack propagation life, is a direct ratio to that of CFL strain. When the CFL strain range is below the value of a ＂strain threshold＂, the interfacial fatigue cracks will not propagate; 2） the process for the initiation and stable or unstable growth of the interracial cracks is observed. The interracial fatigue crack propagation life of the RC beams strengthened with CFL under cyclic bending loads can be precisely predicted by using a similar approach as Paris formula.
出处
《工程力学》
EI
CSCD
北大核心
2008年第11期37-41,共5页
Engineering Mechanics
基金
国家自然科学基金项目(10672060,10272047)
广东省自然科学基金项目(07006538)
关键词
桥梁加固
界面裂缝
疲劳寿命
碳纤维薄板
应变门槛值
bridge reinforcement
interfacial cracks
fatigue life
carbon fiber laminate
strain threshold
