Torsional strength of normal and high strength reinforced concrete beams

Abstract

This paper proposes a simple non-iterative model for the calculation of the ultimate torsional moment in normal-strength and high-strength concrete beams. The two equations of the model relate the torsional strength to the amount and strength of the hoop and the longitudinal reinforcement, the concrete compressive strength, and the outer area of the cross section.The adequacy of the proposed model is evaluated by comparing the calculated torsional strength with the experimentally observed results from 152 test specimens reported in the literature. The results are also compared with the calculations of the ACI and the CSA building code equations, and those of two advanced iterative analytical models. The comparisons show that the proposed equations combine the simplicity of the code equations with the accuracy of the iterative advanced models. They also show that the accuracy of the proposed method was relatively similar in normal-strength and high-strength concrete beams. The comparisons also show that the equations of the Canadian code do not provide an adequate safeguard against over-reinforcement in medium and high strength concrete.