Title: Softening of Concrete in Torsional Members- Design
Author(s): Thomas T. C. Hsu and Y. L. MO
Publication: Journal Proceedings
Appears on pages(s): 443-452
Keywords: angle of twist; beams (supports); building codes; cover; cracking
Ifracturing); reinforced concrete; reinforcing steels; shear properties; strains;
trength; stresses; stress-strain relationships; structural design; thickness; tor-ion.
Based on equilibrium and compatibility conditions, as well as a new stress-strain relationship for softened concrete, a new truss model theory was presented in the first paper of the series. This model accurately predicts the torsional behavior of the 108 test beams available in the literature. The theory, however, is too complex for design purposes. In this second paper of the series, several simplifications for design are considered. They include a simple but accurate formula to obtain the effective depth of wall thickness and three design limitations for over-reinforcement, minimum reinforcement, and concrete cover. A complete set of design recommendations is proposed for torsional reinforced concrete members and is illustrated by two example problems.