Experimental Study And Finite Element Analysis Of Square Axial Compression RC Columns Strengthened With Prestressed CFRP Sheets

CFRP sheets reinforced concrete technology is the rise of a new-style reinforcement method in recent years, which has been widely used in civil engineering fields and has become a focus of research at home and abroad due to its technological advantages in high-strength, light weight, good corrosion resistance, and anti-fatigue performance. However, it is still a blank in domestic and overseas about prestressed CFRP sheets reinforced concrete square columns. Based on this situation, the main work are as follows:(1) according to the mechanical properties of the CFRP sheets and the characteristics of the axial compression columns, a tension device for CFRP sheets that is appropriate to axial compression members was designed. The results shows that the device can tension CFRP sheets effectively.(2) In order to study the mechanical performance on concrete square columns strengthened with prestressed CFRP sheets, according to the reinforcement ratio and tensile stress of CFRP sheets, three groups of twelve concrete square columns were made, each group included an ordinary concrete column and three prestressed CFRP sheets reinforced columns. Then the axial compression test under static load was completed and the experimental data was obtained. Moreover, the collapse state, ultimate bearing capacity, ductility and restraint mechanism about the reinforced columns were studied. The results show that the yield strength and limit bearing capacity were improved effectively, and the increase of limit bearing capacity was involved in the reinforcement ratio and prestress level of CFRP sheets; The prestressed CFRP sheets could put off the appearance and development of initial cracks, limit the lateral deformation of the concrete, improve the ultimate compressive strain and deformation.(3) By the comparative analysis about the ordinary reinforcement method and prestressed CFRP sheets strengthened column, we find that the high-strength characteristic of the CFRP sheet get full used, and the CFRP sheets was changed to active stress state from the passive stress state.(4) The axial compression mechanics properties of ordinary concrete columns, CFRP and prestressed CFRP sheets reinforced concrete square columns were simulated by ANSYS software, the result shows that the test and the analysis value are in good agreement.