Experimental Tests and Design Model for RC Beams Strengthened in Shear Using the Embedded Through-Section FRP Method

This paper presents results of an analytical and experimental investigation on RC T-beams retrofitted in shear with embedded through-section (ETS) fiber-reinforced polymer (FRP). The ETS FRP rod method is a promising method to increase the shear strength of RC beams. As this method develops, the structural behavior of RC beams strengthened with the ETS method needs to be thoroughly characterized and the influencing parameters addressed. In this research study, nine tests were performed on 4,520-mm-long RC T-beams. The parameters of this study are (1) the effect of the surface coating on the FRP bars, (2) the effect of internal transverse steel reinforcement on the FRP shear contribution, (3) the effect of FRP bar spacing, (4) the effect of FRP rod diameter, and (5) the efficiency of the embedded through-section FRP rod method. The main objective of the study is to analyze the behavior of RC T-beams strengthened in shear with ETS FRP rods by varying the parameters just mentioned. New design equations are proposed to calculate the shear contribution of FRP for beams strengthened using the ETS FRP method. The design equations are validated against results collected from the experimental part of the current research study. The proposed model shows an acceptable correlation with the experimental results.