Flexural Behavior of Hybrid FRP-Concrete-Steel Double-Skin Tubular Members
Publication: Journal of Composites for Construction
Volume 10, Issue 5
Abstract
This paper presents the results of an experimental study on the flexural behavior of a new type of hybrid FRP-concrete-steel member as well as results from a corresponding theoretical model based on the plane section assumption and the fiber element approach. This new type of hybrid member is in the form of a double-skin tube, composed of a steel inner tube and an FRP outer tube with a concrete infill between the two tubes, and may be employed as columns or beams. The parameters examined in this study include the section configuration, the concrete strength, and the thicknesses of the steel tube and the FRP tube, respectively. The results presented in this paper show that these hybrid beams have a very ductile response because the compressive concrete is confined by the FRP tube and the steel tube provides ductile longitudinal reinforcement. The beams' flexural response, including the flexural stiffness, ultimate load, and cracking, can be substantially improved by shifting the inner steel tube toward the tension zone or by providing FRP bars as additional longitudinal reinforcement. The predictions from the theoretical model are in reasonably close agreement with the test results. Differences between the test and predicted results arise from factors not considered in the theoretical model, including the existence of a strain gradient in the confined concrete, concentrations of cracks and the slips between the concrete and the two tubes; these are issues to be accounted for in the development of a more accurate model in the future.
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Acknowledgments
The work presented in this paper has received financial support from the Hong Kong Polytechnic University through a research studentship to the first author and the Young Professorship Scheme (Project No: 1ZE-06) and through a Distinguished Young Scholar Award of the Natural Science Foundation of China (Project No. 50329802). The authors are grateful to both organizations for their financial support.
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Information & Authors
Information
Published In
Journal of Composites for Construction
Volume 10 • Issue 5 • October 2006
Pages: 443 - 452
Copyright
© 2006 ASCE.
History
Received: Oct 28, 2005
Accepted: Jan 12, 2006
Published online: Oct 1, 2006
Published in print: Oct 2006
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