Retrofitting of RC Beams using Glass Fiber Reinforced Polymer Sheets: An Experimental Study

Abstract

Objective: An experimental investigation to check flexure and shear behavior of Reinforced concrete (RC) beams retrofitted with glass fiber reinforced polymer composites. Methods/Analysis: Two point symmetric loading. In this study two set of beams were cast out of those first set was weak in flexure (A) and second was weak in shear (B). In all beams same grade of concrete was used but with different structural detailing. In set a three beams (weak in flexure) were cast out of which one was control beam and other two were retrofitted using Glass Fiber Reinforced Polymer Sheets (GFRP) sheets in soffit of beam and till neutral axis including soffit. In set B three beams (weak in shear) were cast out of which one was control beam and other two were retrofitted by using GFRP sheets on sides and U-jacking at corners respectively. Hand wet lay-up method was used for application of GFRP sheets on beam. The retrofitting of beams was done with different amount and configuration of GRFP sheets. Retrofitted RC beams with epoxy-bonded glass fiber reinforced sheets were tested till failure using a symmetric two point loading system. Load, deflection, failure modes and crack pattern of each beam was recorded for a particular GFRP orientation. Experimental investigation concluded that there was increase in load at initial crack and also at ultimate failure for retrofitted beams as compare to control beams. Failure in case of set a retrofitted beams was flexural shear failure. It was also recommended that flexural retrofitting should be performed along with shear retrofitting. In case of set B beams failure was shifted to flexural failure which was initially shear failure. So retrofitting in shear zones was observed most effective. Finding: Retrofitting in shear zones was observed most effective in case of ultimate, flexural failure and shear failure.