Nonlinear Behavior and Simulation of Concrete Columns Reinforced by Steel-FRP Composite Bars
Publication: Journal of Bridge Engineering
Volume 19, Issue 2
Abstract
Steel-fiber-reinforced polymer (FRP) composite bars (SFCBs) have been proposed as a new form of reinforcement for concrete structural elements, such as bridge columns. SFCBs have high initial elastic stiffness provided by the inner steel bars before yielding, positive postyield stiffness owing to the outer FRP after the inner steel bars yield, and superior anticorrosion performance. Furthermore, the postyield stiffness of SFCBs can be fully tailored by changing the steel-to-FRP ratio. Consequently, concrete columns reinforced by SFCBs have exhibited good initial stiffness and stable postyield stiffness experimentally. One potential benefit of the stable and designable postyield stiffness exhibited by SFCB-reinforced columns is to reduce the residual displacement, which is a vital index for evaluating the postearthquake recoverability of bridges. In this paper, the mechanical properties of SFCBs and pushover behavior of concrete columns reinforced by SFCBs are first simulated numerically and validated with experimental results. The influence of FRP types is further evaluated in terms of column deformation capacity. Concrete columns reinforced by steel-basalt FRP composite bars (SBFCBs) demonstrate a better performance-to-cost ratio than that of steel-carbon FRP composite bars (SCFCBs). Nonlinear dynamic analyses of SFCB columns are subsequently conducted under a suite of near-fault ground motions with noticeable acceleration and velocity pulses. The numerical results show that the residual displacement is closely correlated with the peak ground velocity (PGV) and that it decreases with an increase in the postyield stiffness ratio , whereas the peak drift of columns stays almost the same. Finally, a design equation for residual displacement is updated with a drift-dependent displacement coefficient.
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Acknowledgments
The authors acknowledge financial support from the National Basic Research Program of China (Grant No. 2012CB026200), the National “Twelfth Five-Year” Plan for Science and Technology (Grant No. 2011BAB03B09), the National Natural Science Foundation of China (Grant Nos. 51078077 and 51178099), the Natural Science Foundation of Jiangsu Province, China (Grant No. BK2010015), and the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).
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Information
Published In
Journal of Bridge Engineering
Volume 19 • Issue 2 • February 2014
Pages: 220 - 234
Copyright
© 2014 American Society of Civil Engineers.
History
Received: Sep 28, 2012
Accepted: May 23, 2013
Published online: May 25, 2013
Published in print: Feb 1, 2014
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