Punching Shear Strength of CFT Bridge Column to Reinforced Concrete Four-Pile Cap Connections
Publication: Journal of Bridge Engineering
Volume 22, Issue 8
Abstract
This paper presents experimental and analytical studies on the punching shear behavior of concrete-filled steel-tube (CFT) bridge column to pile-foundation connections. Five CFT bridge column to reinforced-concrete (RC) four-pile cap connections were constructed and tested under monotonic downward vertical loads to the columns, and the effects of the connection details, including embedment depths of CFT columns, shear studs, face annular rings, and headed shear reinforcement, on punching shear behavior were evaluated. Test results indicate that the connection details significantly affected the cracking patterns of pile caps and the failure modes of connections. The use of shear studs, face annular rings, headed shear reinforcement, and reduced embedment depths of CFT columns can substantially enhance the punching shear strength of CFT column to RC-pile cap connections. The tested specimen with a face annular ring welded onto the CFT column base showed the most favorable punching shear behavior with the highest loading capacity and the most ductile failure mode. On the basis of the experimental observations, the effective depths of pile caps for CFT columns under punching were proposed, and then the punching shear strength of the tested connections was predicted using current design codes for the design of RC footings. A modified empirical strength model was also developed on the basis of experimental and finite-element analysis results.
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Acknowledgments
The authors gratefully acknowledge the funding provided by the National Natural Science Foundation of China (Grants 51478459 and 51323004), the China Postdoctoral Science Foundations (Grants 2013M540476 and 2015T80601), and Jiangsu Collaborative Innovation Center for Building Energy Saving and Construction Technology (Grant SJXTY1517). The experimental work described in this article was conducted at the Jiangsu Key Laboratory of Environmental Impact and Structural Safety in Civil Engineering in the China University of Mining and Technology, which is supported by a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) [Project Suzhengbanfa (2014)–No.37]. The authors also extend thanks to the staffs and students at the laboratory for their help during test preparation and completion.
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Published In
Journal of Bridge Engineering
Volume 22 • Issue 8 • August 2017
Copyright
© 2017 American Society of Civil Engineers.
History
Received: Jun 7, 2016
Accepted: Jan 27, 2017
Published online: May 17, 2017
Published in print: Aug 1, 2017
Discussion open until: Oct 17, 2017
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