Torsional Stiffness of Prestressing Tendons in Double-T Beams
Publication: Journal of Engineering Mechanics
Volume 137, Issue 1
Abstract
When a prestressed double-T beam is subjected to torsion, a pair of prestressing tendons resists torsional rotation because of the restoring action of the displaced prestressing tendons. A comprehensive formulation to account for the torsional restoring action of double-T beams is presented, based on Vlasov’s hypothesis of considering warping displacement in an open-section. The deformation energies of prestressing tendons and reinforcing bars are calculated based on the deformed geometry to obtain the total potential energy. A two-noded beam element with seven degrees of freedom per node approximates an axial displacement, two translations, two flexural, and one torsional rotations, and a warping displacement to derive the finite-element equilibrium equations by minimizing the potential energy function. The role of prestressing forces of the tendons on the torsional resistance and the limitations of the traditional transformed section approach are addressed when it is applied to torsional problems. As a numerical example, an existing three-span continuous double-T beam is analyzed, and the bimoment and angle of twist are compared to those calculated using conventional three-dimensional finite-element analysis and the analytical solution of governing differential equations.
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Acknowledgments
This paper was partially funded by a Konkuk University Research Committee grant that made it possible for the first writer to stay at the University of Nevada at Reno, United States, to complete this research during his sabbatical year.
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Information & Authors
Information
Published In
Journal of Engineering Mechanics
Volume 137 • Issue 1 • January 2011
Pages: 61 - 72
Copyright
© 2011 ASCE.
History
Received: Jan 22, 2010
Accepted: Jul 19, 2010
Published online: Jul 22, 2010
Published in print: Jan 2011
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