Variation of Web Bounded Shear Reinforcement on Internal Steel Stress

A four-point iosipescu shear test is used to evaluate the effects of CFRP reinforcement on crack width development as well as the effect on the internal steel reinforcement. The test program indicates that the steel reinforcement yields following cracking in a concrete beam test specimen containing a No. 3 29,000 ksi yield strength reinforcing bar. Typically, the specimens when loaded will produce a steel strain around 45 percent of the yield strain prior to the failure between the CFRP and the concrete face. Through this research, it can be assumed the steel will yield with the additional CFRP attached to the concrete face for additional shear reinforcement. This research takes a further approach by establishing an estimation of the maximum amount of CFRP that can be utilized as shear reinforcement while the internal steel reinforcement still yields. The results are found by testing several specimens where the CFRP varies in size while the internal steel reinforcement is held constant.