Response of CFRP retrofitted exterior beam-column joint under cyclic loading

The recent seismic events in Saudi Arabia in the Western and Eastern Region, have led to concerns about safety and vulnerability of reinforced concrete buildings, which were designed only for gravity loads in the past, devoid of any ductile detailing of joints. Deficient beam-column joints (BCJ's) exists in reinforced concrete buildings constructed up to the early nineties in various cities including Makkah, Madinah, Yanbu and Jeddah. This paper presents the results of an experimental study conducted to investigate the behavior of reinforced concrete exterior beam column joints typical of old constructions in the seismically active regions of Saudi Arabia. Four full-scale reinforced concrete BCJ's were tested in the experimental program, in which one set was designed to fail in flexure in the beam and the other set to fail in diagonal shear in the joint. One specimen in each set was retrofitted with CFRP sheet wrapped diagonally around the joint. The columns were first loaded axially and then the BCJ's were subjected to cyclic loading applied at the tip of the beam until failure. The experimental results show that the BCJ's retrofitted by using CFRP sheet are structurally efficient, enhances the strength of the BCJ's and shifts the failure mode from diagonal shear failure in joints to the ductile flexural failure in beams.