Title: A New Approach to the Ultimate Strength of Concrete in Pure Torsion

Author(s): V. Navaratnarajah

Publication: Journal Proceedings

Volume: 65

Issue: 2

Appears on pages(s): 121-129

Keywords: beams (structural);microcraking;plain concrete;reinforced concrete;stresses; tensile strength;torsion;ultimate strength method (structural).

DOI: 10.14359/7461

Date: 2/1/1968

Abstract:
The failure of concrete beams in pure torsion is shown to be initiated by microcracking in the concrete. On this basis an ultimate strength approach is developed for circular and rectangular beams. The ultimate strength of rectangular plain concrete beams is based on the sand heap analogy of plastic torsion with stress levels varying from the stress at microcracking to the ultimate tensile strength of concrete. The strength of reinforced beams is shown to be the sum of the strength of plain concrete and the contribution of the reinforcement. The contribution of the reinforcement towards the ultimate strength is shown to be dependent on the actual stress levels in them at failure.