【作者】 孙宁；

【导师】 曹双寅；

【作者基本信息】 东南大学 ， 结构工程， 2006， 硕士

【摘要】 由于自然因素影响和人为因素的原因,现有的很多基础结构、设施,都急待进行加固和修复。FRP轻质高强的特性,使其在土木工程加固领域中异军突起,有着非常明显的优势。本文的主要内容是FRP加固钢筋混凝土柱即FRP约束混凝土的拐角效应和应力应变分布,通过分析,给出考虑混凝土柱拐角效应的承载力建议公式。本文就FRP在土木工程中的应用结构形式以及其独特的优良性能进行阐述,描述了研究FRP约束钢筋混凝土柱的意义。陈述了FRP约束圆形、方形、矩形截面的混凝土柱体的应力、应变及相关参数模型研究的国内外动态,并对到目前为止关于这方面的研究成果进行了总结,并指出存在的问题。根据FRP约束混凝土常采用的常规三轴受压强度模型形式,将现有矩形柱截面形状(倒角)对抗压强度影响的分析模型归纳为三种,即:倒角半径模型、有效约束面积模型、等效约束应力模型。在分析比较这三种模型的特点和不足的基础上,本文提出了等效圆柱直径模型的概念,即根据环压应力等效的原则,等代出对应的圆柱直径。此模型力学概念清楚,计算公式简洁。本文对轴心和偏心两种受力状态进行有限元仿真,研究FRP布和混凝土沿柱截面的应变分布趋势,和拐角曲率半径对应变分布的影响。分别模拟了无滑移和无粘结工况,通过比较这两种极限状态来考虑介于这两种工况中的实际工况。在基本假设的前提下,从横向约束应力的主要参数(即倒角半径对f frp和D这两个参数的影响)着手来考虑拐角效应的影响,从倒角半径以及矩形截面的宽长比两方面考虑对极限承载力的影响,建立了FRP约束带倒角矩形截面混凝土柱的承载力计算公式,本文对CFRP约束带倒角矩形柱的轴心和偏心受压进行试验,通过试验结果和理论的应变分布及承载力数值的对比分析,表明建立的有限元模型可以很好的模拟应变分布情况。另外,本文还整理了近年来143个圆柱、65个方柱以及36个矩形柱的试验数据,与本文建议公式的理论结果进行分析比较,理论结果与现有实验数据间的误差多在-10%～10%之间,表明本文建议公式有对工程实践有一定的参考价值。更多还原

【Abstract】 Because of its configuration character and its unique excellent performance behaved in civil engineering, FRP is being widely applied in the reinforce field. The current research is focused on the FRP confined reinforced concrete columns. The models of FRP confined circular, square and rectangular sections based on stress, strain and other relative parameters are proposed recently, but these models still have some limitation and are hard to predict the reality accurately. Proposing a new formula of capacity, this thesis provides a more accurate model to emulate the effect of FRP confined circular, square and rectangular sections.The intensity model based on traditional triaxial testing results is adopted. Models of reduction coefficient considering the section shape are collected and concluded into three species, that is, corner radius model, effective confined area model, and equivalent confining stress model. According to the principal of equivalent confining stress, the idea of equivalent diameter is proposed for the first time.The strain distribution along the section and influence affected by corner radius are studied, using finite element analysis software to simulate circumstances under both axial compression and eccentrically load. The actual condition is investigated by simulating non-slip and unbonded conditions. The corner effect is researched from two parts (confining stress and equivalent diameter) which is the main parameter of confining stress, and then, propose suggest formula. Not only the affluence affected by corner radius is taken into account in this formula, but also the ratio of two side length in rectangular specimens.The axial compression and eccentrically loaded experiments of CFRP-confined rectangular columns with corners are taken in this paper. The strain distribution of experiment and the theoretic results are compared and analyzed. Lots of experiment figures are compared with suggestion formula, which comes to a conclusion that the formula suggested by this paper has an adequate precision for actual project.更多还原