Abstract─This paper presents the retrofitting of beam-column joint using CFRP (Carbon Fiber Reinforced Polymer) and steel plate. This specimen was tested until failure up to 1.0% drift. This joint suffered severe damages and diagonal cracks at upper crack at upper column before retrofitted. CFRP were wrapped at corbel, bottom and top of the column. Steel plates with bonding were attached to the two beams and the jointing system. This retrofitted specimen is tested again under lateral cyclic loading up 1.75% drift. Visual observations show that the cracks started at joint when 0.5% drift applied at top of column. Damage of retrofitted beam-column joint occurred inside the CFRP and it cannot be seen from outside. Analysis of elastic stiffness, lateral strength, ductility, hysteresis loops and equivalent viscous damping shows that these values are higher than before retrofitting. Therefore, it is recommended to use this type of retrofitting method for beam-column joint with corbel which suffers severe damage after the earthquake. Keywords─Beam-Column joint, ductility, stiffness, retrofitting. I. INTRODUCTION ARTHQUAKE can cause reinforced concrete buildings to collapse, loss of lives and also staggering economic losses. Most of the structures in Malaysia are not able to resist moderate or major earthquake loading. Under seismic loading, it is important for RC building to have lateral resistance capacity against brittle failure. Non-seismic design buildings which designed using non-seismic code of practice are vulnerable to earthquake excitations. Since demolishing and reconstructing RC buildings are expensive, retrofitting the small fraction of structural components and building may offer a workable solution for ensuring the safety of the building and people. Fiber Reinforced Polymer (FRP) is a popular material which normally used in strengthening RC structural elements in recent years. Experimental results of seismic resistance of FRP retrofitted column improved the lateral strength, stiffness and ductility significantly [1]. Failure of beam-column joint connections can easily lead to the catastrophic collapse of a frame building as often observed in recent earthquakes. Laboratory testing and analysis of the results show that non- seismic structures are vulnerable to earthquake loading. N.H. Hamid is with Faculty of Civil Engineering, Universiti Teknologi Mara, 40450, Shah Alam, Selangor, Malaysia (phone: 006-0173159303, email: norha454@salam.uitm.edu.my). N.D. Hadi is a PhD student at Universiti Teknologi Mara, 40450, Shah Alam, Selangor, Malaysia (phone: 006 -0129707358, email: diyana angelica@yahoo.com). K.D. Ghani is a PhD Student at Universiti Teknologi Mara, 40450, Shah Alam, Selangor, Malaysia (phone: 006-0195708781, email: kaymageeston@ yahoo.com). Failure mechanism of beam-column joint when assessing the nominal strength of a member was predicted to be associated with material strain and stress relationship together with the levels achieved after earthquake [2]. Shear failure usually occur as a result of inadequate transverse reinforcement in the joint and weak-column/strong beam design [3]. Diagonal shear failure in column is the main cause of soft-storey mechanism in RC buildings. High rise buildings are highly exposed to frame damages because it tends to have soft-storey mechanism failure. Soft-storey mechanism is the most frequent failure mode of RC moment frame building [4]. This failure is due to insufficient of reinforcement bars in the beam-column joint and column. When a column is damaged, it forms a plastic hinge zone (PHZ) near the joint and upper part of the column. Therefore, the structure will be more vulnerable to earthquake attack and may experience partial collapse of the structure after the earthquake. Retrofitting of structures should be made to the damage buildings to increase their strength, stiffness and ductility after the earthquake attack. There are many types of retrofitting method which available for fixing joints. Some of the famous ones include steel plate jacketing, plastic hinge relocation and textile reinforced mortar [5], [6]. An experimental work has been conducted on the steel plate rehabilitation of RC beam-column joint and the seismic retrofitting showed the excellence performance after retrofitting [7]. Many researchers opted to use carbon fiber as the external reinforcement material because of its high strength to weight ratio and good fatigue properties [8]. The intention of this study is to study the seismic retrofitting of beam-column joint with corbel tested under lateral cyclic loading using CFRP (Carbon Fiber Reinforced Polymer) and steel plate bonding. The experimental work was conducted and tested up to the maximum failure of the structures. The sub-assemblage of exterior beam-column joint from precast two-storey school building was constructed in Heavy Structural Laboratory, Faculty of Civil Engineering, UiTM. Fig. 1 shows selected sub-assemblage of beam-column joint of a two-storey precast school building. The selected joint consists of one column with two tier corbels and two beams are seating on the corbel supported by the extruder bars which coming out from the corbel. The support conditions at both beams are pinned jointed where the beam is clamped using two steel plates and tight together using four high yield bolts and thread rods. The end condition of column-foundation is designated as partially fixed where the column is jointed to foundation using four extruder bars coming out from Retrofitting of Beam-Column Joint Using CFRP and Steel Plate N. H. Hamid, N. D. Hadi, K. D. Ghani E World Academy of Science, Engineering and Technology International Journal of Civil and Environmental Engineering Vol:7, No:12, 2013 941 International Scholarly and Scientific Research & Innovation 7(12) 2013 ISNI:0000000091950263 Open Science Index, Civil and Environmental Engineering Vol:7, No:12, 2013 publications.waset.org/9996711/pdf