Time-Variant Flexural Reliability of Posttensioned, Segmental Concrete Bridges Exposed to Corrosive Environments
Publication: Journal of Structural Engineering
Volume 140, Issue 8
Abstract
Posttensioned (PT) bridges are used on major thoroughfares because they are economical structures for traversing long spans. Special inspections of these bridges have revealed corrosion of the strands at void locations in the tendons. The integrity of these strands has significant influence on the safety of these bridges. Inspections indicate that many ducts (parts of the tendon that is supposed to protect strands from exposure to aggressive environments) are cracked and many grout holes and vents are opened, allowing direct ingress of moisture and chlorides. This paper presents a framework for assessing the flexural reliability of PT bridges exposed to various environmental conditions. The moment capacity of a PT girder is formulated using probabilistic models for the tension capacity of corroding PT strands exposed to various void and environmental conditions. Using Monte Carlo simulations, the flexural reliability of an example PT bridge is assessed. The research indicates that the flexural reliability index reaches a value below the recommended value within a relatively short period of time when moisture and chlorides infiltrate the tendons. These findings emphasize the critical need for new inspection, assessment, and repair methods for these bridge types.
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Acknowledgments
This research was performed at Texas Transportation Institute and Zachry Department of Civil Engineering, Texas A&M University, College Station, Texas, through a sponsored project from the Texas Department of Transportation (TxDOT), Austin, Texas. This support is much appreciated. Support from project directors Jaime Sanchez, Maxine Jacoby, Dr. German Claros, and Brian Merrill; program coordinator Keith Ramsey; Dean Van Landuyt; Kenneth Ozuna; Steve Strmiska; Tom Rummel; and other TxDOT engineers is acknowledged. The authors also acknowledge the assistance from Dr. Daren Cline, Ramesh Kumar, and Byoung Chan Jung during this research.
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Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 140 • Issue 8 • August 2014
Copyright
© 2014 American Society of Civil Engineers.
History
Received: Jan 17, 2013
Accepted: Oct 29, 2013
Published online: May 23, 2014
Published in print: Aug 1, 2014
Discussion open until: Oct 23, 2014
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