Experimental investigation and strength model of RC deep beams externally bonded by CFRP

Abstract

This paper presents an experimental study on shear strengthening of reinforced concrete (RC) deep beams using externally applied carbon fiber reinforced polymer (CFRP) jackets. A total of 18 RC deep beams were tested using a four-point bending load. The examined parameter included span to depth ratio with or without CFRP strengthening. CFRP strips were applied perpendicular to the probable crack pattern as observed during testing for un-strengthened beams. The properties that is cracking behavior, ultimate strength, deflection, and energy dissipation capacity of beams were evaluated and discussed. The test results showed enhancement in shear strength up to 17% with CFRP. An increase in depth of RC deep beams caused a decrease in the rate of enhancement in shear strength for CFRP strengthened beams as compared to that observed in their counterparts. The experimental test results were compared with the existing design guidelines to assess their application for RC deep beams strengthened with CFRP. A strength equation based on regression analysis was developed to predict the experimental shear strength of RC deep beams strengthened with CFRP. This study showed that the RC deep beams strengthened with CFRP can effectively be used in structural engineering applications with enhanced shear strength and energy absorption capacity.