CFRP板条嵌入式加固损伤钢筋混凝土梁抗弯试验与理论研究

发布时间：2018-05-19 18:10

本文选题：钢筋混凝土梁 + CFRP板嵌入式加固　；参考：《广西大学》2014年博士论文

【摘要】：CFRP板嵌入式加固法是一种新形式的加固方法。CFRP板嵌入式加固法是指预先在需要加固的构件表面开槽,其次向槽中注入粘结材料,然后将CFRP板放入槽中来改善构件受力性能的加固方法。与表面外贴法相比,CFRP板嵌入式加固法具有材料用量少、耐腐蚀、适用于表面不平的构件,与构件传力更有效,遭受意外荷载不易损伤等特点。本文制作了17根钢筋根混凝土梁,试验梁设计时考虑了配筋率、CFRP板加固量和钢筋混凝土梁损伤等3种试验参数。通过测定试验梁的开裂荷载、屈服荷载、极限荷载、变形、裂缝以及试验梁混凝土、钢筋、碳纤维应变,分析CFRP板条嵌入式加固钢筋混凝土梁的破坏机理,研究配筋率、CFRP板加固量和损伤情况等对加固梁裂缝发展、开裂荷载、屈服荷载、极限荷载及刚度的影响,并对比CFRP板条嵌入式加固损伤钢筋混凝土梁与外贴CFRP板条加固损伤钢筋混凝土梁的加固效果。在试验研究的基础上,对加固梁的受弯承载力、挠度计算方法和裂缝计算方法进行理论研究。主要研究工作如下： 1、进行CFRP板条嵌入式加固钢筋混凝土梁的抗弯试验研究,分析CFRP板条嵌入式加固钢筋混凝土梁的破坏机理,研究配筋率、CFRP板加固量和梁损伤情况等对加固破坏形式、裂缝发展、开裂荷载、屈服荷载、极限荷载及刚度的影响。 2、在现有CFRP加固结构构件的承载力计算模型的基础上,根据钢筋混凝土梁抗弯承载力计算的基本理论,探讨CFRP板条嵌入式加固钢筋混凝土梁承载力计算方法。 3、采用最小刚度原则,分析CFRP板条嵌入式加固钢筋混凝土梁在正常使用状态下的刚度,推导加固梁跨中挠度计算公式。 4、根据钢筋混凝土梁裂缝计算理论,推导加固梁在正常使用状态的平均裂缝间距和最大裂缝宽度计算公式。通过上述的试验研究和理论研究,得出如下一些结论： 1、加固梁的破坏形式主要受配筋率和加固量的影响；采用CFRP板条嵌入式加固可以有效的提高加固梁的特征荷载；加固梁的变形性能主要受加固量和初始荷载影响。 2、在不考虑发生CFRP板剥离破坏的情况下,推导建立加固梁的承载力计算公式,计算结果与试验值基本吻合。 3、推导出的挠度计算公式计算正常使用状态下加固梁的跨中挠度,计算值与试验值较吻合。 4、根据钢筋混凝土梁裂缝计算理论,给出了正常使用状态下加固梁的平均裂缝间距和最大裂缝宽度计算公式。通过和试验值比较,计算值与试验值相差较小。
[Abstract]:The embedded reinforcement method of CFRP plate is a new kind of reinforcement method. The embedded reinforcement method of CFRP plate refers to the slotted surface of the member that needs to be strengthened in advance, and then injects the bonding material into the groove. Then the CFRP plate is put into the slot to improve the mechanical performance of the member. Compared with the external surface sticking method, the embedded reinforcement method of CFRP plate has the characteristics of less material consumption, corrosion resistance, suitable for uneven surface members, more effective transmission of force with the members, and less damage to the unexpected loads. In this paper, 17 concrete beams with reinforced roots have been made, and three test parameters, such as reinforcement ratio and CFRP plate reinforcement and damage of reinforced concrete beams, have been considered in the design of test beams. By measuring the cracking load, yield load, ultimate load, deformation, crack and strain of concrete, steel bar and carbon fiber of test beam, the failure mechanism of reinforced concrete beam strengthened with CFRP slab embedded is analyzed. The effects of reinforcement ratio and CFRP plate strengthening amount and damage on crack development, cracking load, yield load, ultimate load and stiffness of strengthened beam are studied. The reinforcement effects of CFRP slab embedded reinforced concrete beam and external CFRP slab reinforced concrete beam are compared. On the basis of experimental study, the flexural bearing capacity, deflection calculation method and crack calculation method of strengthened beams are studied theoretically. The main work of the study is as follows: 1. The bending test of reinforced concrete beam strengthened with CFRP slab embedded is carried out, the failure mechanism of reinforced concrete beam strengthened with CFRP slab embedded is analyzed, and the failure form and crack development of reinforced concrete beam strengthened by reinforced concrete slab reinforced with CFRP slab are studied. Effect of cracking load, yield load, ultimate load and stiffness. 2. On the basis of the existing calculation model of the bearing capacity of reinforced concrete beams strengthened with CFRP, according to the basic theory of flexural bearing capacity calculation of reinforced concrete beams, the calculation method of bearing capacity of reinforced concrete beams strengthened with CFRP slab embedded is discussed. 3. By using the principle of minimum stiffness, the stiffness of reinforced concrete beams strengthened by CFRP slab embedded in normal condition is analyzed, and the calculation formula of deflection of reinforced concrete beams is deduced. 4. According to the theory of crack calculation of reinforced concrete beams, the formulas of average crack spacing and maximum crack width of reinforced concrete beams in normal service are derived. Based on the above experimental and theoretical studies, some conclusions are drawn as follows: 1. The failure form of the strengthened beam is mainly affected by the reinforcement ratio and the amount of reinforcement; the characteristic load of the strengthened beam can be effectively increased by using CFRP slab embedded reinforcement; the deformation performance of the strengthened beam is mainly affected by the reinforcement amount and initial load. 2. Without taking into account the peeling failure of CFRP plate, the formula for calculating the bearing capacity of strengthened beams is derived, and the calculated results are in good agreement with the experimental values. 3. The deflection formula is derived to calculate the mid-span deflection of the strengthened beam under normal working condition, and the calculated value is in good agreement with the experimental value. 4. According to the theory of crack calculation of reinforced concrete beams, the formulas of average crack spacing and maximum crack width of reinforced concrete beams in normal service are given. Compared with the test value, the difference between the calculated value and the test value is small.
【学位授予单位】：广西大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU375.1

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