Torsional Behavior of High-Strength Reinforced Concrete Beams

Abstract

Recent methods for torsional design of reinforced concrete beams tend to the use of space truss analogy, instead of the earlier skew bending theory. A total of (43) rectangular beams made of high strength concrete (HSC) that failed under pure torsion are considered in this work. These have been taken from the literature.Regression analysis was performed on the results to obtain two representative equations to predict: cracking torsional moment Tcr and torsional resistance moment Tr. The first equation is based on (3) major parameters that include concrete compressive strength f’c and sectional dimensions, while the second one is based on (7) major parameters which include the quantification of the influence of both transverse and longitudinal reinforcement.When the ACI 318M-05 Code design equation was applied, it gave a coefficient of variation (COV) of (42.8) percent for the ratio of tested / calculated torsional strength (Tu-test / Tr-calc.), however, the proposed equation has led to a COV of (11.2) percent.