梯度锚固预应力NSM CFRP加固RC梁静力及疲劳性能研究  

Study on Monotonic and Fatigue Behavior of RC Beams Strengthened with Gradually Anchored Prestressed NSM CFRP

作　　者：龚爽 彭晖 粟淼 张建仁 钟卿瑜[1] GONG Shuang;PENG Hui;SU Miao;ZHANG Jianren;ZHONG Qingyu(School of Civil Engineering,Changsha University of Science&Technology,Changsha 410114,China;Key Laboratory of Bridge Engineering Safety Control by Department of Education(Changsha University of Science&Technology),Changsha 410114,China)

机构地区：[1]长沙理工大学土木工程学院,湖南长沙410114 [2]桥梁工程安全控制教育部重点实验室(长沙理工大学),湖南长沙410114

出　　处：《湖南大学学报（自然科学版）》2022年第1期113-123,共11页Journal of Hunan University:Natural Sciences

基　　金：国家自然科学基金资助项目(51578075,51878068);湖南省研究生科研创新项目(CX2018B548)。

摘　　要：针对表层嵌贴预应力CFRP加固梁因黏结端部应力集中导致混凝土保护层易剥离破坏的问题,提出了在CFRP端部设置梯度预应力的构造措施,并通过构件试验系统研究了梯度锚固预应力CFRP加固梁的静载和疲劳性能.试验结果表明:在静力荷载作用下,梯度锚固预应力CFRP加固梁极限荷载较普通表层嵌贴预应力CFRP加固梁最大提高35.06%,破坏模式由端部保护层剥离破坏转变为保护层剥离与CFRP断裂复合破坏,梯度锚固预应力CFRP加固显著提高了RC梁的静载性能,且有明显的黏结应力峰值传递现象;疲劳荷载下梯度锚固预应力加固梁的疲劳寿命也较普通嵌贴加固梁显著提高,且疲劳破坏模式由端部保护层剥离转变为纵向受拉钢筋疲劳断裂;梯度锚固预应力构造显著增强了加固梁抵抗剥离破坏发生的能力,提高了加固梁疲劳性能.The existing studies show that reinforced concrete beams strengthened with prestressed near-surface mounted(NSM)CFRP are easy to fail by concrete cover separation due to the stress concentration at the bonded end of CFRP.In this paper,the construction details of applying gradient prestress at the end of CFRP were proposed,and a series of experiments were carried out to study the load-carrying behavior of the strengthened beams under static and fatigue loads.The test results show that under static load,the ultimate load of beams strengthened with gradually anchored prestressed NSM CFRP was increased up to 35.06%,compared with the beam strengthened with prestressed NSM CFRP.And the failure mode was changed from the concrete cover separation at bonded end into the combined failure of the concrete cover and CFRP fracture.These indicate that the strengthen method with gradually anchored prestressed NSM CFRP can significantly improve the monotonic behavior of beams,and there is an obvious bond stress peak transfer phenomenon.In addition,the fatigue life of beams strengthened with gradually anchored prestressed NSM CFRP was significantly increased,and the fatigue failure mode is changed from the concrete cover separation to the fatigue fracture of longitudinal steel bars.The details of applying gradient prestress enhances the ability of strengthened beams to resist the failure of end concrete cover,and thus improves the fatigue performance.

关 键 词：表层嵌贴 CFRP 梯度锚固 静力性能 疲劳性能 

分 类 号：U447[建筑科学—桥梁与隧道工程]