Title:
Combined Torsion and Bending in Reinforced and Prestressed Concrete Beams Using Simplified Method for Combined Stress-Resultants
Author(s):
Khaldoun N. Rahal
Publication:
Structural Journal
Volume:
104
Issue:
4
Appears on pages(s):
402-411
Keywords:
beams; bending; prestressed concrete; reinforced concrete; shear; stress; torsion
DOI:
10.14359/18770
Date:
7/1/2007
Abstract:
This paper presents a simplified model for the design and analysis of reinforced and partially- and fully-prestressed concrete beams subjected to combined torsional and bending moments. This model is an extension of the existing simplified method for combined stress-resultants (SMCS) model. The interaction between torsion and flexure is achieved by superposing the steel required for the two moments. The observed ultimate loads of 111 beams are compared with the calculations of the proposed model and very good agreement is obtained. This includes comparing interaction diagrams and the effects of concrete strength, stirrups spacing, and T-beam flange width on the ultimate capacity. The calculations by the ACI code equations are also evaluated and shown to give satisfactory and, in some cases, overly conservative, results. The simplicity of the proposed model is illustrated using a design and an analysis example.