CFRP布加固冻融损伤混凝土构件力学性能研究

发布时间：2018-05-20 12:54

本文选题：CFRP布 + 粘结性能　；参考：《沈阳大学》2013年硕士论文

【摘要】：碳纤维增强复合材料（Carbon Fiber Reinforced Plastics，简称CFRP）是将一定长度的碳纤维编织而形成的具有多种功能的复合材料。随着我国建筑事业的快速发展，人们对建筑结构提出了更高的要求。CFRP布具有高强、轻质、减震、优异的力电效应、压敏性及节约建筑面积等性能，同时对混凝土构件的开裂也有一定的延缓作用，因此，CFRP布引起了人们的广泛关注。国外早已将CFRP布加固技术用于工程实践中，而我国科研和工程应用相对较少。为此，本文采用试验研究、理论分析和ABAQUS模拟的方法，研究CFRP布加固混凝土构件的粘结性能，荷载—应变曲线以及CFRP布加固不同冻融损伤试件的抗弯、轴压等力学性能。主要内容有：通过CFRP布加固梁的弯剪试验，，研究加固端的破坏类型，层间位移，荷载、粘贴长度、层数、挠度以及应变之间的关系。通过理论分析，推导出CFRP布加固试件的粘结应力公式，运用ABAQUS对试验进行模拟，并对试验值、理论值、模拟值进行对比。通过多组试件的冻融循环试验，得到冻融试件的质量损失以及动弹性模量损失率，建立了冻融损伤试件的本构关系模型。通过对冻融试件全包加固，进行抗弯试验，得到不同冻融循环次数下全包加固试件应力－应变曲线的上升段。通过理论计算，得到试件的抗弯承载力，对试验值、理论值进行对比分析。通过对CFRP布加固普通混凝土柱进行轴压试验，研究其受力性能，加固方式，破坏形态，环向、竖向变形等；通过对全包、分包等变化参数的对比分析，分析表明：全包加固方式可明显提高试件的承载力，有效约束加固柱的环向变形。在试验分析基础上，提出了CFRP布加固柱的承载力计算公式。利用ABAQUS模拟加固柱的受力全过程以及开裂过程，得到荷载与竖向变形的关系曲线。对混凝土试件分别进行50、100、150次冻融循环，试件受到不同程度的损伤，采用CFRP布对损伤试件加固后，通过对加固柱进行轴心受压试验，研究其受力性能、破坏形态、加固方式、竖向变形、承载能力以及不同位置的应变。试验表明：CFRP布加固技术能有效提高冻融损伤试件的承载力，随着冻融循环次数的增加，加固试件的承载力提高越明显，并与加固普通混凝土试件进行对比，得到损伤试件加固后的特有属性。通过修正损伤混凝土的本构关系，得到损伤加固试件的承载力。利用ABAQUS对CFRP布加固冻融损伤柱的受力过程进行模拟，得到CFRP布加固损伤柱荷载与竖向变形的关系曲线。
[Abstract]:Carbon Fiber Reinforced Plastics, (carbon Fiber Reinforced Plastics,) is a kind of composite material with many functions formed by braiding a certain length of carbon fiber. With the rapid development of the construction industry in our country, people put forward higher requirements for the building structure. The CFRP cloth has the properties of high strength, light weight, shock absorption, excellent electromechanical effect, pressure sensitivity and saving building area, etc. At the same time, the cracking of concrete members is also retarded, so CFRP cloth has attracted wide attention. CFRP reinforcement technology has been used in engineering practice in foreign countries, but scientific research and engineering application are relatively few in our country. Therefore, by means of experimental study, theoretical analysis and ABAQUS simulation, the bond behavior, load-strain curve of concrete members strengthened with CFRP sheets and the flexural and axial compression properties of different freeze-thaw damage specimens strengthened with CFRP sheets are studied in this paper. The main contents are: The relationship between failure type, interstory displacement, load, bonding length, floor number, deflection and strain of the strengthened beam was studied by the bending shear test of the beam strengthened with CFRP cloth. Through theoretical analysis, the formula of bond stress of CFRP reinforced specimen is deduced. The experiment is simulated by ABAQUS, and the experimental value, theoretical value and simulation value are compared. The mass loss and dynamic elastic modulus loss rate of freeze-thaw specimens were obtained by freeze-thaw cycle tests. The constitutive model of freeze-thaw damage specimens was established. Through the bending test of the freeze-thaw specimen, the rising section of the stress-strain curve of the whole cladding specimen was obtained under different freeze-thaw cycles. Through theoretical calculation, the flexural capacity of the specimen is obtained, and the experimental and theoretical values are compared and analyzed. Through the axial compression test of the ordinary concrete columns strengthened with CFRP sheets, the mechanical properties, reinforcement methods, failure patterns, circumferential and vertical deformation, and so on, are studied, and the variation parameters such as the whole package and the subcontract are compared and analyzed. The analysis shows that the load bearing capacity of the specimens can be improved obviously and the circumferential deformation of the strengthened columns can be effectively restrained. On the basis of experimental analysis, a formula for calculating the bearing capacity of CFRP reinforced columns is put forward. The relationship between load and vertical deformation is obtained by using ABAQUS to simulate the whole stress process and cracking process of strengthened columns. The concrete specimens were subjected to 50100150 freeze-thaw cycles respectively, and the specimens were damaged to varying degrees. After strengthening the damaged specimens with CFRP cloth, the axial compression tests were carried out on the strengthened columns to study their mechanical properties, failure patterns and strengthening methods. Vertical deformation, bearing capacity and strain at different locations. The test results show that the bearing capacity of freeze-thaw damage specimens can be improved effectively by using the technology of w CFRP. With the increase of freeze-thaw cycles, the bearing capacity of strengthened specimens is increased more obviously, and compared with that of ordinary concrete specimens. The special properties of the damaged specimens after strengthening are obtained. By modifying the constitutive relation of damaged concrete, the bearing capacity of the specimens strengthened with damage is obtained. Using ABAQUS to simulate the mechanical process of freeze-thaw damaged columns strengthened with CFRP sheets, the relationship curve between the load and vertical deformation of damaged columns strengthened with CFRP sheets was obtained.
【学位授予单位】：沈阳大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU37

【参考文献】