Experimental Investigation of an Appropriate Anchorage System for Flange-Bonded Carbon Fiber–Reinforced Polymers in Retrofitted RC Beam–Column Joints

Abstract

External application of fiber-reinforced polymers (FRPs) for the seismic retrofit/repair of reinforced concrete (RC) beam–column joints has been extensively investigated in the last decade. However, the majority of the suggested FRP schemes follow the application of the composite sheets on the webs of the beam and the joint core which would be impeded in real three-dimensional structures due to the presence of cross beams and slabs. In addition, upgrading code-compliant RC joints using a practical FRP scheme needs to be scrutinized in detail. A desirable retrofitting scheme for this type of joints may follow the application of composite sheets on the top and bottom sides (flanges) of the beam and columns aimed at increasing the flexural strength of beam–column joints. However, the major issue of concern for a flange-bonded FRP is providing adequate development length from the critical section to transfer the FRP tensile forces from beam to columns and vice versa. To overcome this concern, a novel anchorage system for flange-bonded carbon FRP (CFRP) is developed in this study and its efficiency is evaluated through a comprehensive experimental program. In total, nine small-scale (