The Research Of Flexural Performance Of Loaded Rc Beam On Normal Section Reinforced With Prestressed CFRP Sheets

CFRP sheets reinforced concrete technology is the rise of a new-style reinforcement method, which has been widely applied in practice. So far, Many universities and research institutions at home and abroad have done a lot of research and also have got some valuable theories. However, the actual application shows that there are some defects in this method: because of the concrete members strengthened with CFRP sheets in the load-bearing state, the stress of CFRP sheets will fall behind the concrete stress when the members bear loads again, which will make high strength performance of the CFRP sheets can not be used fully. In order to solve the problem, this paper carried out the research of the flexure properties about the beams strengthened with prestressed CFRP sheets, the main work are as follows:1、In order to realize the tension of CFRP sheets, an device has been designed.2、For the flexure properties research of the prestressed CFRP sheets reinforced concrete beams under loading, according to the reinforcement ratio, three groups of twelve concrete beams were made, each group included an ordinary concrete beam with no reinforcement for comparison and three prestressed CFRP sheets reinforced beams. The load level of the reinforcement beams is the ultimate bearing capacity by40%of its comparison beam, the tension stress of CFRP sheets is800MPa,1200MPa and1600MPa respectively. Then the test with two-point loading was completed and the test date such as the bending capacity of cross section, crack distribution and deformation were obtained. On the basis of test data, the flexure properties of the concrete beams strengthened with prestressed CFRP sheets was studied, and the following conclusion were got:(1) The yield strength and limit bearing capacity of reinforced concrete beams were improved effectively, and the increase of limit bearing capacity was involved in the reinforcement ratio and prestress level of CFRP sheets;(2) The bending rigidity of reinforced concrete beams was enhanced significantly and it is also shows:when the reinforcement ratio is high, the bending rigidity has no obvious influence to the prestress of CFRP sheets;(3) The prestressed CFRP sheets could effectively restrain the development of crack, and the crack width has related to the prestress of CFRP sheets;(4)Compare prestress CFRP sheets reinforcement to the CFRP sheets reinforcement, the former could overcome the effect of lagging stress, and give full play to the high strength of CFRP sheets.3、Based on the test data and numerical analysis results by using the ANSYS finite element software, the working mechanism of the reinforced concrete beams were further studied.