Seismic strengthening of reinforced concrete beams using high-ductility cementitious composite (HDCC)

Abstract

This research investigated the seismic behaviors of shear-insufficient reinforced concrete (RC) beams strengthened with high-ductility cementitious composite (HDCC). Six cantilever beams, including two reference beams, two beams strengthened with HDCC jacket and two beams strengthened with steel bar mesh-reinforced HDCC jacket, were subjected to cyclic concentrated loading. The variable parameters were the strengthening schemes (presence or absence of the steel bar mesh in the HDCC jacket) and shear span-to-depth ratio (2 or 4). The test results showed that the shear capacity, ductility and energy dissipation capacity of the RC beams were remarkably improved after strengthening with HDCC. Installing steel bar mesh in the HDCC jacket can further enhance the deformation capacity and energy dissipation capacity of the HDCC-strengthened beams. However, there was little difference between the shear capacity of the beams strengthened with the steel bar mesh-reinforced HDCC and the shear capacity of the beams strengthened with HDCC because the steel bar mesh could decrease the continuity and compactness of the HDCC strengthening layer. Finally, a calculation method was used to estimate the shear capacity of the HDCC-strengthened beams based on the variable angle truss model. This method was validated with the experimental results in this study and the existing literatures about the beams strengthened with ECC or SHCC.