【作者】 欧阳煜；

【导师】 钱在兹；

【作者基本信息】 浙江大学 ， 结构工程， 2001， 博士

【摘要】 纤维增强塑料（Fiber Reinforced Plastic，简称FRP）加固混凝土结构，是近年来出现的一种结构加固新方法。由于具有耐腐蚀、施工简便快捷、几乎不改变构件原有的尺寸等特点，这一加固方法已得到广泛的应用，具有良好的经济效益。 在前人研究的基础上，通过大量的玻璃纤维（GFRP）片材加固钢筋混凝土梁、柱和节点的试验研究，探讨了加固试件的加固效果、破坏机理和理论分析方法。本文的研究得到福建省科委重点课题（编号：98-Z-35）、福建省建委课题（编号：JK-99-10）的大力资助。本文的主要内容归纳如下： 一、进行了6根GFRP片材抗弯加固混凝土梁的试验研究。本文提出加固梁截面弯矩和曲率的分析模型，计算结果和试验数据吻合较好。对GFRP片材厚度、刚度、强度、混凝土强度等级和配筋率等设计变量进行了参数分析，并对不同情况下的弯矩—曲率曲线进行了比较。结果表明，GFRP片材有效地提高了梁的刚度和弯曲强度。该加固方法对于低配筋率混凝土梁特别有效。 二、试验表明，抗弯加固梁可能在GFRP片材端部保护层混凝土发生局部破坏，这种破坏是由GFRP片材端都应力集中引起的。本文在线弹性理论的基础上，提出了采用GFRP片材抗弯加固混凝土梁在任意线性荷载作用下，片材端部锚固剪应力和剥离正应力的计算公式，本文公式计算结果和有限元分析结果及试验数据基本吻合。参数分析表明，锚固剪应力和剥离正应力不但和GFRP片材的厚度、弹性模量、片材长度等因素有关，而且和粘胶层的厚度、弹性模量有关。本文公式可用于计算片材端部的最大锚固剪应力和最大剥离正应力，防止局部粘结破坏。 三、进行了15根GFRP片材抗剪加固混凝土梁的试验研究，探讨了不同加固方式和剪跨比对抗剪承载力的影响。试验结果表明，GFRP片材的受力机理和箍筋相同，梁抗剪承载力取决于GFRP片材的有效应变。根据试验结果提出了GFRP片材有效应变的计算公式，并依据现行规范的计算模型，提出了GFRP片材加固梁抗剪承载力计算公式。 四、进行了20根GFRP片材加固混凝土方柱的轴压性能试验研究，探讨了不同加固方式、加固率、混凝土强度等级等因素对轴压承载力的影响。试验结果表明，GFRP片材可以有效地提高混凝土方柱的强度和延性，GFRP片材的侧限约束作用随片材厚度的增加而降低。本文提出一个划分柱截面有效约束区和非有效约束区的方法。根据试验结果，提出了GFRP片材约束混凝土的应力—应变关系。计算结果和试验数据基本吻合。 浙江大学申请傅士学位论文 摘 要D 五、进行了6个GFny片材加固混凝土梁柱节点在低周反复荷载作用的试D 验研究。试验结果表明GFRP片材加固节点是一个有效的加固方法，节点的抗7 剪强度和延性比加固前有较大的提高。本文提出了节点核心区水平剪力的计算D 模型，并给出了考虑混凝土、箍筋、GFRP片材共同贡献的节点抗剪承载力计算l 方法。计算结果和试验数据基本吻合。D更多还原

【Abstract】 Strengthening Concrete structure with Fiber Reinforced Plastic (FRP) is a new Structural repair method in recent year. This method has been found to be economical and efficient to apply, because of its resistance to electrochemical erosion, low manpower demand for application and minimal changes in geometrical dimensions of the member.Based on the predecessors’ work, this paper investigates strengthening effect, failure mechanism and theory analysis by large quantities experiments of reinforced concrete beams, columns and beam-column joints strengthened with the Glass Fiber Reinforced Plastic (GFRP) sheet. The financial support is provided by the Fujian Science Committee (Grant No. 98-Z-35) and the Fujian Construction Committee (Grant No. JK-99-10). The following are summarizes of experimental study and theoretical analysis:1. Six reinforced concrete beams externally bonded by the GFRP sheet are tested for flexural strengthening. An analytical model is presented to predict the stresses and deformations in concrete beam section, and the results agree well with the experimental results. A parametric study is conducted to investigate the effects of design variables such as thickness, stiffness and strength of the GFRP sheet, concrete compressive strength, and steel reinforcement ratio. The moment versus curvature diagrams for various combinations of these variables are plotted and compared. The results indicate that bonding GFRP sheet to a concrete beam can increase the stiffness and flexural strength of the beam. The method is particularly effective for beams with a relatively low steel reinforcement ratio.2. Experiments have indicated local failure of the concrete layer between the GFRP sheet and longitudinal reinforcement in retrofitted beams. This mode of failure is caused by local stress concentration at the sheet end. Based on the linear elastic theory, a method has been developed to calculate the bonding shear stress and the peeling normal stress of a reinforcement beam with a strengthening sheet and loaded with an arbitrary linear distributed load. The results agree well with the finite element method and the experimental results. The parametric study shows that the bonding shear stress and the peeling normal stress are influenced not only by the thickness, the elastic modulus and the length of the GFRP sheet, but also by the thickness and the elastic modulus of the adhesive. This method can be used to check the maximum bonding shear stress and the maximum peeling normal stress at the end of the GFRP sheet, and to prevent the local bonding failure.3. Fifteen reinforced concrete beams externally bonded by the GFRP sheet are tested for shear strengthening. Test variables include GFRP strengthening method and shear span-depth ratio. The experiment results show that the contribution of GFRP sheet to shear capacity is same as steel stirrups, and the shear capacity isdepend on the effective GFRP sheet strain. The effective GFRP sheet strain decreases with increasing GFRP sheet axial rigidity. Based on the experimental results, an analytical model for the effective GFRP sheet strain is developed, and a calculated method for the design with the framework of modern code formats is presented.4. Twenty concrete square columns externally wrapped by GFRP sheet are tested for axial compression strengthening. Test variables include thickness and spacing of GFRP strap, GFRP strengthening ratio and concrete compressive strength. The experiment results indicate that GFRP sheet can enhance the strength and ductility of concrete, and the confining action of GFRP sheet decreases with increasing the thickness of GFRP sheet. A method to determine the areas of effectively confined concrete and ineffectively confined concrete on the rectangular column section is presented. The compressive stress-strain relationship of concrete confined by GFRP sheet is proposed. A comparison between the experimental results and those of analytical results indicates that the proposed model provides satisfactory predictions of ul更多还原