【作者】 吕伟荣；

【导师】 施楚贤；

【作者基本信息】 湖南大学 ， 结构工程， 2003， 硕士

【摘要】 粘贴钢板、玻璃纤维、碳纤维等材料是结构直接加固中一种较为简便的加固形式，近年来被广泛地应用于工程实际中，尤其以粘贴碳纤维为研究和应用的热点。由于粘贴材料性能的不同，加固设计的计算方法也不一。因此，在工程应用中极不方便，也很难进行对比。但是，上述这类加固方法在承载力计算上有很大的相似性，完全可以用一个统一的通用公式进行计算，这有利于选择最佳的加固材料。基于这一想法，本文将这类加固方法统称为“粘贴加固”，并主要研究粘贴加固钢筋混凝土受弯构件正截面承载力计算的通用公式。 本文总结出粘贴加固的基本原理：通过粘贴高强的抗拉材料，进而使得受弯构件的受压区混凝土高度增加，从而提高原钢筋混凝土受弯构件的正截面承载力。 由平截面假定和界限破坏理论，并保证粘贴加固梁具有一定的变形能力和较为充分地发挥混凝土的抗压性能，本文以受压区混凝土边缘应变达到峰值应变（0.002），而加固材料应变刚好达到极限值（0.01）的界限破坏时混凝土受压区高度做为粘贴加固梁设计高度的下限值ξ_c0bh。同时，引入可靠性鉴定标准，推导出其相应的设计上限值ξ_maxh₀（见表2.2）。由粘贴加固上、下限，引入钢筋的界限破坏，本文将粘贴加固受弯构件的设计破坏形态分为三类（Ⅰ、Ⅱ、Ⅲ类），并给出相应的承载力计算公式和各自的使用范围。 为简化计算Ⅰ类设计破坏形态时粘贴加固构件的抗弯承载力，本文引入误差调整系数γ₁，将规范混凝土应力—应变公式（2.1）简化成一阶线性公式（2.17）并代入计算。结果表明，该公式的计算值不仅具有较好的精度，且偏于安全。 本文在有关文献的基础上，引入误差调整系数γ₂，推导出钢筋混凝土受弯构件二次受力下粘贴加固材料滞后应变ε_tag的计算公式（2.63）～（2.66）。经检验，该套公式计算简便且与试验结果吻合较好。同时，本文根据受弯加固构件的二次受力理论，提出了一整套较为完整的粘贴加固梁在二次受力情况下的正截面承载力计算公式，并给出相应的工程实例计算。 本文采用改进的弯矩—曲率算法，较为准确地计算出粘贴加固受弯构件的开裂弯矩、屈服弯矩，计算结果与试验结果吻合较好。本文还将改进的算法运用于粘贴加固受弯构件的荷载—挠度曲线和二次受力问题的计算中，得出与试验结果吻合较好的计算曲线（图3.17～3.20）。同时，程序计算结果表明，加固梁在二次受力的作用下，屈服弯矩随着初始荷载的增加而减小，但极限抗弯承载力受初始荷载影响较小。 本文引入新的对比方法，即不同材料的加固在最终均达到同样的极限抗弯承载力时，比较其各自的弯矩一曲率和荷载一挠度变化情况，并自行编制程序进行计算。同时，本文还从理论的角度上对不同材料粘贴加固梁之间以及加固梁与未加固梁的曲率延性性能给予了定性分析，并得出与本文程序计算结果（图3．22～3．25）基本一致的结论。更多还原

【Abstract】 Strengthening reinforced concrete structure with externally-bonded steel plate, glass fiber, carbon fiber, steel mesh and so on, which is a simple and convenient method in direct reinforcement, is widely applied to engineering in recent years, especially carbon fiber is the focus of research and application. At present, there are many different calculated formulas in accordance with different bonded materials. Therefore, those formulas are not very convenient for application, and are very difficult to be compared to select the most suitable one. Although the different bonded materials behave disagreement with each other, Nevertheless, the calculating theory of load capacity is similar. So they can completely enjoy a unified formula. On the basis of this thought, the paper calls this kind of reinforcement as "bonded reinforcement", and mainly studies the universal formula, which calculate the ultimate flexural capacity of the reinforced concrete members, strengthened with externally bonded materials.The paper has concluded the fundamental principle of sticking reinforcement. That is to improve the ultimate flexural capacity of the original reinforced concrete beam through externally bonded with high-strength tension materials.In order to assure the bonded-strengthened beams to have ductility and fully exert the compressive capability of concrete, the paper deduces the lower limit compressive height used in design from the plane section assumption and theory of limit destruction. The lower limit compressive height is when the strain of compressive edge fiber reaches its peak value (0.002) and the externally bonded material reaches its limited strain (0.01). Meanwhile, the design upper limited height is presented by introducing the degree of reliability (shows as table 2.2). Therefore, drawing from the lower and upper limit designed height and steel limit destruction, the paper classifies the design destructive forms of bonded-strengthened beams into three categories ( I , II,III), and gets the relevant integrated formula for calculating flexural capacity and gives therelevant design example of engineering.In order to simplify the calculated procedure, the error coefficient (r1) has beenintroduced to paper. And so, the criterion formula (2.1), which calculates strain and stress in concrete, can be replaced by one-variable formula (2.17). Such simplifiedformula (2.17) cannot only accurately calculate the flexural capability ofbonding-reinforced beams, but its calculated results have definite security.Based on literature and introducing the error coefficient (r2), the paper infers theformula (2.63-2.66), which is applied to calculate the lag strain of bonded materials (Elag) under the secondary load. Through examination, the formula works very conveniently and closely reflects the statue of experiments. Introducing beam’s secondary load theory, a series of integrated calculated formula and a designed example that calculate the area of bonded material for strengthening reinforced beams under the secondary load.The bonded-strengthened beams’ cracked-moment and yielded-moment can be accurately calculated by introducing the improved algorithm of moment-curvature to paper’s program. And the calculated results closely coincide with experimental results. Furthermore, the paper, through applying the improved algorithm to the load-deflection curve and secondary load, also the calculated curves closely coincided with experimental results (showed as chart 3.17-3.20). Meanwhile, the results of program show that, under secondary load, the bonding-reinforced beams’ yield-moment would decrease as the original load increase, but the original load wouldn’t remarkably influence the ultimate flexural capacity.The paper presents a new comparative method. That is to make the different strengthened forms by externally bonded with different materials reach the same ultimate flexural capacity, and contrast with each load-deflection and moment-curvature curve, which are calculated by paper’s更多还原