Pure torsional behavior of RC beams in relation to the amount of torsional reinforcement and cross-sectional properties

Abstract According to the current ACI318-19 building code, torsional strength is calculated by reflecting the effective area of concrete and the properties of torsional reinforcement, regardless of the cross-sectional properties of the reinforced concrete members. Past research has revealed that the torsional failure mode of RC members subjected to torsional strength is influenced by the contribution of the concrete and the amount of torsional reinforcement. In this study, 11 experiments were conducted to examine the pure torsional behavior of RC members in relation to their cross-sectional properties, and the amount of torsional reinforcement. The experimental variables were (1) the properties of the solid and hollow cross-sections, (2) the amount of arranged torsional reinforcement compared to that of the ACI 318-19 building code, (3) the yield strength of the torsional reinforcement, and (4) the spacing of the torsional reinforcement. The results showed that solid cross-sections and hollow cross-sections had similar levels of torsional strength. In addition, the specimens with a smaller amount of arranged torsional reinforcement were engaged in ductile behavior when compared with the ACI 318-19 building code, regardless of their cross-sectional properties.