Experimental investigation on the behaviour of retrofitted reinforced concrete beam - Column joints with Gfrp wrap subjected to load reversal

Moderate and severe earthquakes have struck different places in the world, causing severe damage to reinforced concrete structures. Upgradation to higher seismic zones of several cities and towns in the country has also necessitated in evolving new retrofitting strategies. Recent evaluation of civil engineering structures has demonstrated that most of them will need major repairs in the near future. Retrofitting of existing structures are the major challenges that modern civil engineering field is facing these days. Beam-column joints, being the lateral and vertical load resisting members in RC structures are particularly vulnerable to failures during earthquakes and hence their retrofit is often the key to successful seismic retrofit strategy. The existed reinforced concrete beam-column joints which were designed as per code IS 456:2000 must be strengthened in order to satisfy the condition given in code IS 13920:1993. In this paper an attempt has been made to study the behavior of reinforced concrete beam-column joints retrofitted with glass fiber reinforced polymer sheets. Totally six exterior reinforced concrete beam-column joint specimens (control) were cast and tested to failure. Three specimens had reinforcement details as per code IS 456:2000. Remaining three specimens had reinforcement details as per code IS 13920:1993. Various percentage of load carrying capacity of column was given as axial load in the column. Push and pull load was applied at the free end of the cantilever beam till failure. The failed three beam-column joint specimens had reinforcement details as per code IS 456:2000 were retrofitted by removing the concrete in the joint portion and recasting with concrete of same grade and subsequently wrapped with Glass fiber reinforced polymer (GFRP) sheet to strengthen the specimens. The performance of the retrofitted beam-column joints was compared with the control beam-column joint specimens and the results were presented in this paper. 2010 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.