Investigation of the Efficacy of Steel Section Reinforcement in Hybrid Deep Beam Applications

Abstract

This research provides an experimental evaluation of the shear behavior of deep beams reinforced with alternative shear reinforcement systems. It also explores the optimal arrangement of concrete types within hybrid deep beams to reduce both material costs and structural weight while maintaining load-bearing capacity. A total of six specimens were prepared and categorized into two main groups. Group 1 (G1) included two control beams one fully cast with normal-strength concrete and the other with high-strength concrete both featuring identical reinforcement layouts. Group 2 (G2) comprised four hybrid beams that incorporated both normal- and high-strength concrete arranged in a triangular configuration guided by the Strut-and-Tie Model (STM). In all specimens, traditional strut reinforcement was replaced with 40×40×4 mm angle steel sections. Each beam measured 1200 mm in length, 500 mm in depth, and 150 mm in width. Under single-point loading with a consistent shear span-to-depth ratio (a/d = 1), the hybrid beams achieved a 75% increase in shear strength and a 235.6% enhancement in stiffness compared to the normal-strength control beam. Additionally, toughness and ductility improved by 77.5% and up to 116.4%, respectively. When compared with the high-strength control beam, the hybrid specimens still demonstrated capacity gains of up to 25.6%, along with notable improvements in stiffness, toughness, and ductility. These results underscore the advantages of hybrid concrete configurations and alternative reinforcement methods in enhancing deep beam performance.