Published Resources Details
Journal Article
- Title
- Torsion in reinforced and prestressed concrete beams
- In
- Journal of the Institution of Engineers, Australia
- Imprint
- vol. 28, no. 9, Sep 1956, pp. 235-240
- ISBN/ISSN
- 0020-3319
- Abstract
Although torsion occurs only as a secondary effect in concrete structures, the subject has been investigated on at least thirteen occasions over the past fifty years, and there is now sufficient information for laying down a safe and economical procedure.
Plain concrete in pure torsion fails in diagonal tension. Failure can, therefore, be delayed by suitable shear reinforcement. A much greater increase in torsional strength is, however, possible by the use of prestressing.
In practice, torsion occurs as a secondary effect of bending, e.g., in girders with horizontal projections and in eccentric edge beams. Failure of prestressed concrete in combined bending and torsion is also determined by the magnitude of the principal tensile stress. The failure of normal reinforced concrete in combined bending and torsion is, however, a more complex problem, and two criteria of failure must be considered: failure in torsion depends on the tensile strength of the concrete; failure in bending can only occur as a result of a compression failure of the concrete. The concrete-encased rolled steel joist is essentially a special case of the normal reinforced concrete beam. The steel joist provides most of the bending resistance, and the concrete encasement most of the torsional resistance.
Twenty-three references are given, and the principal results are briefly described. A design procedure similar to that established for the design of sections subject to both bending moments and shear forces is suggested.