Probabilistic Characterization of Live Load Using Visual Counts and In-Service Strain Monitoring
Publication: Journal of Bridge Engineering
Volume 12, Issue 1
Abstract
It has been argued that the AASHTO LRFD design code for maximum live loads on highway bridges is overly conservative. In an attempt to determine the level of conservativeness, if any, the writers developed a methodology incorporating real-time visual data collection from traffic cameras coupled with structural strain response of girder bridges. Average daily truck traffic along with frequency of multiple presences (same lane as well as adjacent lanes) and lane-wise truck traffic distribution were estimated for a steel-girder highway bridge on I-95 in Delaware. These data compared well with predictions from a Poisson process based model developed for this study. Statistical properties of girder moments in single and multiple presence conditions were determined as well. In this particular example, the girder design moment on the approach span according to AASHTO specifications was found to be about 3.5 times higher than that estimated from the in-service data.
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Acknowledgments
Part of this work was supported by National Science Foundation Grant No. NSFEEC-0139017.
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Information & Authors
Information
Published In
Journal of Bridge Engineering
Volume 12 • Issue 1 • January 2007
Pages: 130 - 134
Copyright
© 2007 ASCE.
History
Received: Mar 28, 2005
Accepted: Jun 22, 2005
Published online: Jan 1, 2007
Published in print: Jan 2007
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