Differences between Calculated and Measured Long-Term Deflections in a Prestressed Concrete Girder Bridge
Publication: Journal of Performance of Constructed Facilities
Volume 24, Issue 6
Abstract
The monitoring of five precast, prestressed bridge girders during fabrication and service provided the opportunity to observe changes in camber over time. These camber variations were compared with corresponding strain and temperature measurements. Each of the girders was cast outside during the winter. As a result, the cold ground acted as a heat sink, and a significant temperature gradient existed during curing of each of the instrumented girders. These temperature gradients are believed to have caused the wide range in the short- and long-term cambers. A procedure to calculate the effect that curing temperatures have on girder camber is presented. In addition, the measured camber values are compared with predicted values using the multiplier method, improved multiplier method, and a detailed time-step method. It was found for the long-span girders that the measured camber values were on average within 10% of the predicted values using the detailed time-step method, but ranged from 22% lower to 27% higher for the simpler methods.
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Acknowledgments
The writers would like to thank the Washington Department of Transportation and the Federal Highway Administration for the support that made this research possible. In addition, sincere appreciation goes to Dr. John Stanton and Marc Eberhard for their continued advisement.
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Information & Authors
Information
Published In
Journal of Performance of Constructed Facilities
Volume 24 • Issue 6 • December 2010
Pages: 603 - 609
Copyright
© 2010 ASCE.
History
Received: Mar 16, 2009
Accepted: Jan 21, 2010
Published online: Jan 28, 2010
Published in print: Dec 2010
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