Measurement of the Timoshenko Shear Stiffness. I: Effect of Warping
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Volume 11, Issue 3
Abstract
Fiber-reinforced polymer (FRP) composite beams are increasingly finding use in construction. Due to their lower stiffness relative to steel sections, the design of FRP structures is usually deflection controlled. Furthermore, shear deformation can be significant in FRP beams, thus, requiring the use of the Timoshenko beam theory to estimate deflections. However, the Timoshenko shear stiffness can be difficult to measure. Part of the measurement error has been attributed to shear warping effects. It has been hypothesized that warping restraints at loading points and supports increase the apparent shear stiffness to a degree that is significant at relatively short spans, e.g., to 15. In this study, the influence of warping on short to moderate length FRP beams under various types of loading and boundary conditions is considered using finite-element analysis. In particular, a commercially available thin-walled FRP beam was investigated. The results suggest that warping has a negligible effect for thin-walled beams at reasonable spans, i.e., . On the contrary, the effective shear stiffness is found to decrease at shorter span lengths. This is the first of two papers in a series.
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Information & Authors
Information
Published In
Journal of Composites for Construction
Volume 11 • Issue 3 • June 2007
Pages: 336 - 342
Copyright
© 2007 ASCE.
History
Received: Jul 11, 2005
Accepted: May 16, 2006
Published online: Jun 1, 2007
Published in print: Jun 2007
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