Reinforced Concrete Structures with Hybrid Technology of Pre-stressed CFRP Sheets and Pre-screwed Bolts

摘要

The carbon fiber reinforced composite polymer (CFRP) reinforcement is currently one of the most popular and effective methods for retrofitting and strengthening concrete structures. However, the non-prestressed CFRP reinforcement cannot make full use of the tensile strength of CFRP , the crack development of the stiffening beam cracks cannot restrained actively either. The failure of a strengthened or retrofitted structure with the non-prestressed CFRP was usually caused by the breakdown of the bond at the CFRP-epoxy interface or at the concrete-epoxy interface where is weaker than other place. Much effort had been made in researching community to improve the bond strength and restrain the crack development of the strengthening beam cracks actively. The full CFRP strength can usually be achieved in the strengthened or retrofitted structure with the prestressed CFRP. The Pre-screwed bolts fastening is another new mechanical fastening technique that is used to bond one material to another to improve the bond interface strength. Therefore, this paper introduces a new hybrid bonding prestressed technique that combines the prestressed CFRP reinforcement and the pre-screwed bolts fastening. A new tensioning equipment was developed in order to prestress CFRP. The strengthened reinforced concrete (RC) beam experiments have been finished to check the strengthening effect. The experimental tests demonstrated the new hybrid technology of pre-stressed CFRP sheets and pre-screwed bolts can make full use of the tensile strength of CFRP and restrain the crack development of the strengthening beam cracks actively.