Development of Bridge Column Longitudinal Reinforcement in Oversized Pile Shafts
Publication: Journal of Structural Engineering
Volume 142, Issue 11
Abstract
This paper presents an experimental investigation to determine the embedment length required for longitudinal reinforcement in a bridge column extending into an oversized pile shaft, and the amount of transverse reinforcement required for the pile shaft to prevent premature bar anchorage failure due to concrete splitting induced by bar slip. Four full-scale column–oversized pile assemblies were tested under quasi-static cyclic lateral loading. The test specimens had different embedment lengths for the column reinforcement, different amounts of transverse reinforcement in the piles, different sizes of longitudinal bars, ranging from No. 8 to No. 18 (25 to 57 mm) bars, and different column-to-pile diameter ratios. All column–pile assemblies behaved in a ductile manner with plastic deformation occurring near the base of the columns despite some cone-shaped fractures and tensile splitting cracks occurring in the top portion of the piles. The test results show that the embedment length for the column reinforcement can be significantly reduced as compared to that required in current design specifications. The study also shows that an engineered steel casing designed according to a formula proposed here can effectively confine the pile shaft and significantly reduce splitting cracks.
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Acknowledgments
Funding for the research presented in this paper was provided by Caltrans under Contract No. 59A0710. The authors appreciate the technical input provided by Caltrans engineers throughout this study. However, the opinions expressed in this paper are those of the authors and do not necessarily reflect those of the sponsor. The experiments presented in this paper were conducted in the Charles Lee Powell Structural Engineering Laboratories at UC San Diego. The authors would like to express their gratitude to the laboratory staff for their professionalism and high-quality technical support. The authors would also like to thank Mr. Charles Cummings, a former UC San Diego undergraduate student, for his assistance in the preparation of the column–pile assembly tests.
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Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 142 • Issue 11 • November 2016
Copyright
© 2016 American Society of Civil Engineers.
History
Received: Oct 7, 2015
Accepted: Apr 15, 2016
Published online: Jun 27, 2016
Published in print: Nov 1, 2016
Discussion open until: Nov 27, 2016
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