Performance analysis of strengthening reinforced concrete beams under pure torsion using galvanized steel sheets: Experimental and numerical investigation

Abstract

Reinforced concrete (RC) beams can be subjected to torsion, and failure due to torsion is brittle and poses a significant risk to occupants. Moreover, strengthening of existing RC beams in torsion may be required due to the upgrade of the structures or as part of structural rehabilitation. This paper explores the innovative method of strengthening RC beams in torsion using galvanized steel sheets (GSS) and investigates their performance under torsion failure. A series of tests are carried out to explore the effectiveness of the proposed strengthening method, exploring the key parameters, namely the orientation of GSS strips (i.e., horizontal, vertical, and inclined) and combining different GSS strip orientations on the torsional behavior of strengthened beams. It is found that applications of GSS significantly improve the torsional behavior of RC beams, with the inclined orientation of GSS strips outperforming the performance of beams strengthened with horizontal or vertical configurations. Furthermore, combining different GSS strip orientations (i.e., vertical and inclined GSS strips or horizontal and inclined GSS strips) further improves their torsional performance. A 3D finite element model (FEM) is also developed, and the accuracy of the FEM predictions is validated against experimental data, followed by performing a parametric study.