Closed-Form Model and Parametric Study on Connection of Concrete-Filled FRP Tubes to Concrete Footings by Direct Embedment
Publication: Journal of Engineering Mechanics
Volume 137, Issue 5
Abstract
Concrete-filled fiber-reinforced polymer (FRP) tubes (CFFTs) have been introduced as a new system for piles, columns, and poles. A simple moment connection based on direct embedment of the CFFT into concrete footings or pile caps, without using dowel-bar reinforcement, has been proposed by the authors. Robust analytical models to predict the critical embedment length () were also developed and experimentally validated. In this paper, a comprehensive parametric study is carried out using the models developed earlier along with a newly developed closed-form model for the general case of axial loading, bending, and shear applied to the CFFT member. The parameters studied are the diameter (), thickness (), length outside the footing (), and laminate structure of the FRP tube, as well as the tube-concrete interface bond strength (), concrete compressive strength in the CFFT () and footing (), and the magnitude and eccentricity of axial compressive or tensile loads. It was shown that increasing , , , and of the footing, or the axial compression load, reduces , whereas increasing and of the CFFT, the fraction of longitudinal fibers in the tube, or the axial tension load, increases . As the axial load eccentricity increases, reduces for tension loads and increases for compression loads until both cases converge asymptotically to the same value, essentially that of pure bending.
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Acknowledgments
The authors wish to acknowledge the financial support provided by the UNSPECIFIEDOntario Ministry of Research and Innovation (MRI) and UNSPECIFIEDQueen’s University, through the postdoctoral fellowship to the first author and the Early Researcher Award and the Chancellor’s Research Award provided to the second author.
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© 2011 American Society of Civil Engineers.
History
Received: Mar 7, 2010
Accepted: Oct 7, 2010
Published online: Oct 30, 2010
Published in print: May 1, 2011
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