Bridge Lifetime System Reliability Under Multiple Limit States

Allen C. Estes, United States Military Academy
Dan M. Frangopol, University of Colorado at Boulder

Article comments

© American Society of Civil Engineers. The definitive version can be found online at http://dx.doi.org/10.1061/(ASCE)1084-0702(2001)6:6(523).

NOTE: At the time of publication, the author Allen Estes was affiliated with the United States Military Academy - West Point, NY. Currently, August 2008, he is Head and Professor of Architectural Engineering at California Polytechnic State University - San Luis Obispo.

Abstract

A system reliability approach to minimizing the life-cycle cost of a deteriorating structure offers significant advantages such as a rational assessment of the assumed risk of failure, and an understanding of the importance and contribution of individual components to the overall reliability of the structure. The reliability of a structural system as a whole is the measure of its overall performance. This measure has to include both ultimate and serviceability limit states. A system model of a structure traditionally consists of a series-parallel combination of strength-based component limit states. Serviceability limit states however, can play a tremendously important role in optimizing the inspection and repair of a deteriorating structure. This paper proposes the use of serviceability flags as a means to incorporate serviceability concerns into a strength-based reliability analysis. Using highway bridges as an example, available data sources for serviceability flags are considered. The effect of including serviceability flags in an optimum life-cycle analysis is illustrated on a specific highway bridge.