Impact of Posted Load Limits on Highway Bridge Reliability
Publication: Journal of Bridge Engineering
Volume 10, Issue 3
Abstract
The effectiveness of posted load limits in reducing annual maximum live load effects, thus enhancing bridge reliability, is investigated for 12 and 40 m simple span highway bridges. Novel analytical expressions are derived for event gross vehicle weight (GVW) distributions that account for violation of posted load restrictions, and the corresponding annual maximum GVW distributions are presented. Annual reliability indices associated with load restrictions computed using typical bridge posting criteria and different compliance levels are compared to the target reliability index. For the case of perfect compliance, a posted load restriction can significantly reduce maximum annual live load effects and so enhance the reliability. Under imperfect compliance, however, a violation rate as low as 2.5% (i.e., one illegal truck in 40 ignores the posting) causes the mean value and variability of the annual maximum live load effect distribution to increase significantly, resulting in a significant loss in reliability. Thus, unless posted loads are strictly enforced, the effectiveness of enhancing existing bridge reliability with a posted load restriction is questionable.
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Acknowledgment
The writers gratefully acknowledge financial support provided by the Natural Science and Engineering Research Council of Canada and the Commonwealth Scholarship program.
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Information & Authors
Information
Published In
Journal of Bridge Engineering
Volume 10 • Issue 3 • May 2005
Pages: 321 - 330
Copyright
© 2005 ASCE.
History
Received: May 13, 2003
Accepted: May 4, 2004
Published online: May 1, 2005
Published in print: May 2005
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