铝合金筋加固混凝土梁界面黏结性能与剥离承载力研究  

Study on Bonding Performance and Debonding Capacity of RC Beam Strengthened with NSM Aluminum Alloy Bars

作　　者：邢国华[1] 罗小宝 马军 常召群 党会学[1] XING Guo-hua;LUO Xiao-bao;MA Jun;CHANG Zhao-qun;DANG Hui-xue(School of Civil Engineering,Chang an University,Xi an 710061,Shaanxi,China)

机构地区：[1]长安大学建筑工程学院,陕西西安710061

出　　处：《建筑科学与工程学报》2021年第1期41-50,共10页Journal of Architecture and Civil Engineering

基　　金：国家自然科学基金项目(51868073);陕西省技术创新引导专项(基金)项目(2019CGHJ-06);中央高校基本科研业务费专项资金项目(300102288302)。

摘　　要：通过试验研究与有限元模拟计算,分析了铝合金筋嵌入式加固混凝土梁的破坏模式和承载能力,对比了不同的剥离承载力计算模型,获得了铝合金筋应力和应变以及界面黏结应力沿梁跨度方向的分布曲线,推导出界面黏结-滑移关系和剥离承载力计算公式。结果表明:铝合金筋加固混凝土梁界面剥离破坏模式分为界面剥离破坏和混凝土保护层剥离破坏,混凝土梁加固后,抗弯性能和变形性能均得到改善;界面剥离破坏是由跨中弯曲裂缝引起的局部界面黏结失效,最终延伸至加固筋一端从而造成加固筋剥离;混凝土保护层剥离破坏是由于加固筋端部应力集中,造成周围混凝土保护层发生剥离脱落;沿着梁的跨中至梁端方向,铝合金筋的应力和应变逐渐降低,界面黏结应力先增大后减小且应力最大值随荷载的增加而增加;铝合金-结构胶界面和结构胶-混凝土界面的黏结-滑移关系曲线可分为4个阶段,即弹性阶段、弹性软化阶段、弹性软化剥离阶段和软化剥离阶段;建议的计算模型可以较准确地预测铝合金筋加固混凝土梁的剥离承载力。Through experimental research and finite element analysis,the failure mode and bearing capacity of concrete beams strengthened with near surface mounted(NSM)aluminum alloy(AA)bars were analyzed,different debonding capacity calculation models were compared,the distribution curves of stress and strain of the AA bars and interface bond stress along the beam span direction were obtained,and the interface bond stress-slip relationship and the calculation formula of debonding capacity were derived.The results show that there are two modes of interface debonding failure of concrete beams strengthened with AA bars,namely,the intermediate crack debonding and concrete cover separation.The flexural performance and deformation performance of concrete beams are improved after the beams being strengthened.The intermediate crack-induced debonding between NSM bars and concrete is induced by the extension of bending cracks in the constant moment region.The concrete cover separation occurs because of the extension of several cracks induced by the stress concentration at the end of the NSM bars.Along the direction from mid-span to beam end,the stress and strain of the AA bars gradually decrease,the interface bonding stress firstly increases and then decreases,and the maximum stress increases with the increase of the load.The debonding process of RC beam strengthened with NSM AA bars can be divided into four stages,namely,elastic stage,elastic softening stage,elastic softening debonding stage and softening debonding stage.The proposed calculation model can accurately predict the debonding capacity of concrete beams strengthened with AA bars.

关 键 词：混凝土梁 嵌入式加固 铝合金 有限元 黏结-滑移关系 剥离承载力 

分 类 号：TU377.9[建筑科学—结构工程]