Shear Strength Study of RC Beams Retrofitted Using Vinyl Ester Bonded GFRP and Epoxy Bonded GFRP

Abstract

Many of the existing reinforced concrete structures throughout the world are in urgent need of rehabilitation, repair or reconstruction because of deterioration due to various factors like corrosion, lack of detailing, failure of bonding between beam-column joints, increase in service loads, etc., leading to cracking, spalling, loss of strength, deflection, etc. The recent developments in the application of the advanced composites in the construction industry for concrete rehabilitation and strengthening are increasing on the basis of specific requirements, national needs and industry participation. The need for efficient rehabilitation and strengthening techniques of existing concrete structures has resulted in research and development of composite strengthening systems. Fiber Reinforced Polymer (FRP) composite has been accepted in the construction industry as a promising substitute for repairing and in incrementing the strength of RCC structures. FRP composites possess some outstanding properties such as: resistance to corrosion, good fatigue and damping resistance, high strength to weight ratio, and electromagnetic transparency. FRPs over the years have gained respect in terms of its superior performance and versatility and now are being used not only in housing industry but its potentials are being continuously explored for its use in retro-fitting and strengthening of damaged structural members. This paper focuses exclusively on shear behaviour of RCC beams and the Vinyl-Ester bonded GFRP and Epoxy bonded GFRP wrapped retrofitted RCC beams. Beams were retrofitted with 1.2 mm Epoxy bonded GFRP sheets and 0.9 mm Vinyl-Ester bonded GFRP sheets using epoxy resins. In all a total of 10 beams were tested and the respective readings were recorded. The beams were full-wrapped and strip-wrapped and tested for shear behavior analysis. Cracking and deflection of GFRP reinforced concrete beams are analyzed experimentally. It was  concluded that the wrapping of GFRP sheets increases the ultimate load carrying capacity of RCC beams. Also a cost analysis was done in order to get a cost effective solution for the issue of retrofitting, which is a rising concern in the recent times.

Keywords: Glass Fibres, Vinyl Ester Bonded GFRP, Epoxy bonded GFRP, Shear Strength, RC Beams