Enhancing torsional performance of reinforced concrete beams: a comparative analysis of shear reinforcement strategies

Abstract

Torsion failure poses a critical threat to the structural integrity of reinforced concrete, particularly in seismic hazard zones. This study aims to overcome this difficulty by conducting a thorough examination of the torsional characteristics of Reinforced Cement Concrete (RCC) beams. This study examined the torsional characteristics of various RCC beams by utilizing different configurations of shear reinforcements. The objective was to determine an effective alternative shear reinforcement configuration in comparison to the traditional Non-welded Rectangular Stirrup Beam (NRSB). Comparing three types of beams, namely NRSB, Welded Rectangular Stirrup Beam (WRSB), and Welded Warren Truss Beam (WWTB), a novel warren truss-shaped shear reinforcement was introduced. All beams were constructed with consistent dimensions of concrete and uniform weights of reinforcement, including 16 mm bars for the top and bottom longitudinal reinforcement and 10 mm bars as shear reinforcements. Two separate concrete mix ratios were evaluated, specifically 1:1.5:1.5 and 1:2.5:2.5 (by volume) respectively. Theoretical calculations based on elastic theory were used to determine the angle of twist for each beam. The torsional moment resistance of WRSB and WWTB was found to be 4.4% and 1% higher, respectively, compared to the traditional NRSB, while using a mix ratio of 1:1.5:1.5. Regarding the alternative mixture ratio, the torsional moment for WRSB was 10% more, whereas for WWTB it was 2.4% less. As a result, the WRSB specimens exhibited the highest torsional moment for both mix ratios, but the NRSB and WWTB specimens had comparable values.