Flexural strengthening of RC beams using near surface mounted fibre reinforced polymers

This paper presents an experimental study to investigate the behaviour of Reinforced Concrete (RC) beams strengthened in flexure with Near Surface Mounted (NSM) technique using Glass and Carbon Fibre Reinforced Polymers (GFRP & CFRP). An experimental program consisting of seven full scale reinforced concrete beams were constructed and strengthened in flexure with FRPs. The investigation included three parameters; technique used (NSM or Hybrid), type of FRP used (Carbon or Glass), and amount of FRP used. All beams were tested under four point bending set-up. The test results included behaviour, ultimate capacity, deflection, cracking, and mode of failure. All strengthened beams showed an increase in the capacity ranging between 55 and 133% compared with the reference beam. Most of the strengthened beams had debonded in a sudden failure except the NSM-GFRP strengthened beams. The NSM-CFRP strengthened beams carried larger loads in terms of ultimate capacity than the NSM-GFRP beams but they showed less ductile behaviour. The NSM-GFRP strengthened beam, however, showed good ductile behaviour with high deflection values at ultimate load. This gave amble warning before failure and can be considered as an advantage of strengthening RC beams with NSM-GFRP system.