【作者】 周延阳；

【导师】 姚谏；

【作者基本信息】 浙江大学 ， 结构工程， 2005， 硕士

【摘要】 近二十年来纤维增强塑料(fiber-reinforced plastic/polymer,FRP)以其轻质、高强、耐腐、抗疲劳等诸多优于建筑钢材的特点,在各国被广泛应用于结构加固工程。其中,采用“表层嵌贴”(near-surface mounted,NSM)FRP法加固混凝土结构是一项近几年才被提出的加固新技术,其与“表面粘贴”(externally bonded)FRP法相比有很多优点,因此具有广阔的工程应用前景和试验研究前景。 混凝土表层嵌贴FRP的粘结机理研究在对该加固技术的研究、应用中占有基础性地位,应当首先得到深入研究。 本文采用改进梁剪试验方法,对13个表层嵌贴碳纤维增强塑料(carbon fiber-reinforced plastic,CFRP)板混凝土试件的粘结机理进行研究。考察了影响粘结性能的三个因素:嵌贴长度、粘结剂层厚度、加载方式。研究内容包括:粘结破坏模式、破坏机理、粘结性能影响因素、粘结剪应力—滑移关系等。 基于试验研究,提出了混凝土表层嵌贴CFRP板—环氧树脂粘结剂界面剥离机理;基于理论分析,得到CFRP板嵌贴自由端未滑移时粘结微分方程闭合解,并利用该闭合解,提出一种新的方法来间接拟合局部粘结剪应力—滑移关系;利用数值法,解CFRP板嵌贴自由端开始滑移时的粘结微分方程,求得混凝土表层嵌贴CFRP板极限粘结承载力。另外,基于Bertero-Popov-Eligehausen(BPE)局部粘结剪应力—滑移模型,提出了一种改进BPE模型。更多还原

【Abstract】 In virtue of the advantages of fiber-reinforced plastic/polymer (FRP), light-weight, high-strength, nice environmental and fatigue resistibility, it has been broadly used in structural strengthening in the past two decades. In recent years, near-surface mounted (NSM) FRP reinforcement is emerging as a potential strengthening technique in practice and a valuable challenge in research, which, in some cases, presents substantial advantages with respect to externally bonded reinforcement.The bond mechanics of NSM FRP composites to concrete should be obtained first for it is the primary step in the whole investigation of NSM FRP reinforcement.A total of 13 specimens have been investigated in a new modified beam-shear test program in order to study bond behavior of NSM carbon-FRP (CFRP) strips to concrete. Three variables which are suspected influencing bond behavior of NSM CFRP strips to concrete have been investigated, such as: bonded length, adhesive thickness and loading mode. This paper focuses on bond failure modes, failure mechanics, factors influencing bond behavior, bond shear stress-slip relationship.Based on the test results, a debonding mechanics between CFRP strips and epoxy adhesive has been proposed. Based on modeling analysis, a closed-form solution of bond differential equation (when CFRP doesn’t slip at free bonded end) has been worked out, and a new indirect procedure of evaluating local bond shear stress-slip relationship has been carried out. The ultimate bond strengths of NSM CFRP strips to concrete have been obtained based on a numerical solution of bond differential equation. In addition, this paper proposes a new modified Bertero-Popov-Eligehausen (BPE) model fitting local bond-slip curves.更多还原