Experimental investigation of an RC exterior beam column joint behavior strengthened with FRP

Abstract

Beam Column joints experience large shear forces during seismic events and may undergo brittle failure which is not preferred. Eminent scholars suggested different technologies and methods to strengthen the beam column joints. FRPs, which have high strength to weight ratio, are also suggested as retrofitting materials for strengthening RC structural members. From literature review, it is found that FRPs are very effective in strengthening the shear, flexural and axial capacities of beams and columns. They are being effectively used for retrofitting exterior and corner joints due to ease of accessibility and placement. This experimental study is under taken to study the behavior of RC exterior beamcolumn joints which lack in shear reinforcement and strengthened by FRPs. Total three models have been prepared of which one joints have been strengthened by Carbon FRP (CFRP) Fabrics and remaining two was control specimens with tie and without tie at joints. The samples have been subjected to incremental cyclic loading provided by hydraulic jacks under constant axial or gravity load and their load-deformation behaviors have been measured by dial gauges and video extensometer. The behavior of the strengthened joint are compared with the control model. The joints without shear reinforcement undergo brittle failure under cyclic loading. But their ductility increases with increased concrete strength. The joints strengthened by the CFRPs show better load bearing capacity with enhanced ductile behavior.