Live-Load Analysis of Posttensioned Box-Girder Bridges
Publication: Journal of Bridge Engineering
Volume 17, Issue 4
Abstract
This paper presents an evaluation of flexural live-load distribution factors for cast-in-place box-girder bridges. The response of a typical box-girder bridge was recorded during a static live-load test. This test involved driving two heavily loaded trucks across the instrumented bridge on selected load paths. The instruments used to record the response of the bridge were strain gauges, displacement transducers, and tilt sensors. The measured data were then used to calibrate a finite-element modeling scheme using solid elements. From this finite-element model, the theoretical live-load distribution factors and load ratings for the test bridge were determined and compared with the factors and ratings predicted in the AASHTO LRFD specifications. A parametric study of cast-in-place, box-girder bridges using the calibrated finite-element modeling scheme was then used to investigate how various parameters such as span length, girder spacing, parapets, skew, and deck thickness affect the flexural live-load distribution factors. Based on the results of the parametric study, a new equation, which more accurately predicts the exterior girder distribution factor, is proposed.
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Acknowledgments
This publication was supported by a subcontract from Rutgers University, Center for Advanced Infrastructure and Transportation (CAIT), under DTFH61-08-C-00005 from the U.S. Department of Transportation, Federal Highway Administration (USDOT-FHwA). Any opinions, findings, and conclusions or recommendations expressed in this publication are those of the writers and do not necessarily reflect the views of Rutgers University or those of the U.S. Department of Transportation, Federal Highway Administration. The writers would also like to thank Caltrans for help and cooperation with the testing of the Lambert Road Bridge. The writers also thank Bridge Diagnostics, Inc., for assistance during the live-load test.
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Information & Authors
Information
Published In
Journal of Bridge Engineering
Volume 17 • Issue 4 • July 2012
Pages: 644 - 651
Copyright
© 2012. American Society of Civil Engineers.
History
Received: Apr 20, 2011
Accepted: Aug 25, 2011
Published online: Aug 27, 2011
Published in print: Jul 1, 2012
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