NSM CFRP-混凝土界面疲劳黏结性能研究  

Study on Fatigue Bond Behavior of NSM CFRP-concrete Interface

作　　者：丑佳璇 张智涛 张建仁 粟淼[1] 彭晖 CHOU Jia-xuan;ZHANG Zhi-tao;ZHANG Jian-ren;SU Miao;PENG Hui(School of Civil Engineering,Changsha University of Science&Technology,Changsha 410004,Hunan,China;National-local Joint Engineering Laboratory of Technique for Long-term Performance Enhancement of Bridges in Southern District,Changsha University of Science&Technology,Changsha 410004,Hunan,China)

机构地区：[1]长沙理工大学土木工程学院,湖南长沙410004 [2]长沙理工大学南方地区桥梁长期性能提升技术国地联合工程实验室,湖南长沙410004

出　　处：《中国公路学报》2022年第2期234-246,共13页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(52178186,51578078,51878068)。

摘　　要：NSM CFRP加固技术能显著提升混凝土结构的受力性能,已受到桥梁结构加固领域的广泛关注。CFRP与混凝土界面的可靠黏结是充分发挥加固效果的前提,目前针对静载下界面黏结性能的研究相对较多,但关于界面疲劳黏结性能的研究十分有限。为此,开展了疲劳荷载下的单剪拔出试验,通过对黏结界面的疲劳寿命、应力分布、滞回曲线、骨架曲线、黏结刚度和耗散能等进行分析,研究了疲劳荷载下NSM CFRP与混凝土界面的黏结行为与退化机理,考察了疲劳应力幅和黏结长度等因素与界面疲劳黏结性能的相关性,得到了适用于NSM CFRP加固混凝土体系发生剥离破坏情况下的S-N曲线模型,并基于局部黏结区段的疲劳寿命分析,提出了一种评估NSM CFRP-混凝土界面疲劳黏结性能的新型多功能模型。研究结果表明:NSM CFRP与混凝土界面的黏结性能显著受到疲劳荷载影响,即便是低于疲劳极限的应力幅也会造成黏结界面退化,增加黏结长度虽无法抑制界面退化,但会使疲劳寿命大幅增长;明确了疲劳荷载下黏结界面的受力行为并将其概括为弹性变形、塑形损伤、界面退化和完全剥离4个阶段,阐明了各阶段的受力机理;所得多功能模型可在已知疲劳应力幅、黏结长度和疲劳寿命三者其二的情况下预测另一个量,且具有较高的准确性。Near surface mounted(NSM) carbon fiber reinforced polymer(CFRP) reinforcement technology can significantly improve the mechanical performance of concrete structures and has attracted attention in the field of bridge structure reinforcement. A reliable bond between the CFRP and concrete interface is the premise of giving full play to the reinforcement effect. At present, many studies have been carried out on the interface bond behavior under static loads, but research on the interface fatigue bond behavior is very limited. Therefore, a single-shear pullout test under fatigue load was conducted in this study. The bond behavior and degradation mechanism of the interface between the NSM CFRP and concrete under fatigue load were studied by analyzing the fatigue life, stress distribution, hysteretic curve, skeleton curve, bonding stiffness, and dissipated energy of the bonding interface. The correlation between interface fatigue bond behavior and factors such as fatigue stress amplitude and bonding length was investigated, and the S-N curve model suitable for the case of debonding failure of the NSM CFRP reinforced concrete system was obtained. Based on the fatigue life analysis of the local bonding section, a new multifunctional model for evaluating the fatigue bond behavior of the NSM CFRP-concrete interface was proposed. The main conclusions are as follows: the bond behavior of the interface between the NSM CFRP and concrete is significantly affected by the fatigue load, and even the stress amplitude below the fatigue limit causes interface degradation. Although increasing the bonding length cannot inhibit interface degradation, the fatigue life is greatly increased. The mechanical behavior of the bonding interface under fatigue load is summarized into four stages, elastic deformation, plastic damage, interface degradation, and complete debonding, and the mechanism of each stage is explained. The multifunctional model can predict the fatigue stress amplitude, bonding length or fatigue life with high accuracy when th

关 键 词：桥梁工程 黏结性能 疲劳试验 FRP NSM 剥离破坏 

分 类 号：U445.72[建筑科学—桥梁与隧道工程]