Title: Prestresses Concrete Under Torsion, Shear, and Bending

Author(s): Denis McGee and Paul Zia

Publication: Journal Proceedings

Volume: 73

Issue: 1

Appears on pages(s): 26-32

Keywords: beams (supports);bending;loads (forces);prestressed concrete; prestressing steels;shear properties;torsion; web reinforcement.

DOI: 10.14359/11052

Date: 1/1/1976

Abstract:
The results of an experimental investigation on 45 prestressed concrete beams are presented. Sixteen of the beams contained web reinforcement COP responding to ACI 318-71 minimum requirements for flexure shear in prestressed beams and the remaining 29 contained none. Except for the prestressing strand no other longitudinal reinforcement was used. The members containing web reinforcement were tested in an attempt to determine the minimum web reinforcement requirements for prestressed members subjected to torsion. The results indicate that the reinforcement provided was inadequate with respect to ductility and strength, A knowledge of the behavior of prestressed members without web reinforcement under combined loading is essential to the development of a design procedure. This investigation indicates that linear elastic load-deformation relationships can be used to predict the precracking behavior of such members. In addition, the maximum principal stress theory of failure reasonab!y predicts the cracking load of members subjected to combined loading. The ultimate strength of members without web reinforcement can be represented by a nondimensional, circular, torque-shear interaction curve for shear-span-to-depth ratios from 3 to 6.