Techno Press
Techno Press

Structural Engineering and Mechanics   Volume 61, Number 5, March10 2017, pages 577-592
DOI: http://dx.doi.org/10.12989/sem.2017.61.5.577
 
Prestressed concrete beams under torsion-extension of the VATM and evaluation of constitutive relationships
Luís F.A. Bernardo and Jorge M.A. Andrade

 
Abstract     [Full Text]
    A computing procedure is presented to predict the ultimate behavior of prestressed beams under torsion. This computing procedure is based on an extension of the Variable Angle Truss-Model (VATM) to cover both longitudinal and transversal prestressed beams. Several constitutive relationships are tested to model the behavior of the concrete in compression in the struts and the behavior of the reinforcement in tension (both ordinary and prestress). The theoretical predictions of the maximum torque and corresponding twist are compared with some results from reported tests and with the predictions obtained from some codes of practice. One of the tested combinations of the relationships for the materials was found to give simultaneously the best predictions for the resistance torque and the corresponding twist of prestressed beams under torsion. When compared with the predictions from some codes of practice, the theoretical model which incorporates the referred combination of the relationships provides best values for the torsional strength and leads to more optimized designs.
 
Key Words
    PC beams; torsion; longitudinal and transversal prestress; VATM; stress-strain relationships
 
Address
Luís F.A. Bernardo and Jorge M.A. Andrade: Department of Civil Engineering and Architecture, Centre of Materials and Building Technologies (C-made),University of Beira Interior, Covilhã, Portugal
 

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