Prestressed Concrete Beams Under Combined Torsion, Bending, and Shear


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Title: Prestressed Concrete Beams Under Combined Torsion, Bending, and Shear

Author(s): Alfred Bishara

Publication: Journal Proceedings

Volume: 66

Issue: 7

Appears on pages(s): 522-524

Keywords: beams (supports) ; bending; interaction diagram; prestressed concrete; research; shear strength; torsion; ultimate strength method; web reinforcement.

Date: 7/1/1969

Presents an experimental investigation on the behavior and ultimate capacity of prestressed concrete beams of rectangular, I and T cross sections, with web reinforcement, subjected to the simultaneous combined action of torsion, bending, and shear. The elastic and plastic behavior of 24 beams tested was analyzed and the rupture criteria defined. Neither th e cracking load nor the ultimate capacity could be satisfactorily predicted by Saint Venant’s elastic torsion theory and the principal stress criterion. The variation in the ultimate capacity for each group of beams having the same cross section is illustrated using nondimensional interaction curves. An empirical expression for calculating the pure torsional strength of prestressed concrete members has been developed. For sections where the moment/shear value is constant, empirical expressions have been developed to define the relation between torque and moment, and torque and shear, at ultimate capacity.