Embedded Through-Section FRP Rod Method for Shear Strengthening of RC Beams: Performance and Comparison with Existing Techniques

Abstract

Embedded through-section (ETS) technique is a recently developed method to increase the shear capacity of reinforced concrete (RC) using fiber-reinforced polymer (FRP) rods. The ETS method presents many advantages over existing methods, such as externally bonded FRP sheets (EB FRP) and near-surface mounted FRP rods (NSM FRP). Unlike EB and NSM methods where the FRP relies on the concrete cover of RC beams, in the ETS method, the FRP relies on the concrete core of the RC beam, which offers a greater confinement and hence improves bonding performance. Additionally, the ETS method requires less concrete preparation compared with EB and NSM methods. The objective of this paper is to present results of an experimental investigation that studies the effectiveness of the ETS method and compares the performance of the ETS method with both EB and NSM methods. In total, 12 tests are performed on 4,520-mm-long T-beams. The parameters investigated are as follows: (1) the effectiveness of the ETS method, compared with EB FRP sheet and NSM FRP rod methods; (2) the presence of the internal steel; and (3) the internal transverse steel reinforcement ratio (i.e., spacing). The test results confirm the feasibility of the ETS method and reveal that the performance of the beams strengthened in shear using this method is significantly superior compared with that of the beams strengthened with EB and NSM methods.