ABSTRACT
Infrastructure plays a key role in the economic prosperity and the quality of life of a nation. If not maintained, the quality of service of that infrastructure drops due to the effects of deterioration, and in some cases, results in sudden failure and loss of lives. A recent report from the American Society of Civil Engineers emphasized the poor conditions of the infrastructure in the U.S. (ASCE, 2001). Inspection and maintenance activities are expensive and time-consuming. The type and amount of data to be collected during inspection vary according to the specific approach adopted by an infrastructure management agency. Taking bridges as an example of infrastructure, there are nearly 590,000 bridges in the American National Bridge Inventory that must be inspected at least every two years. The current approach to bridge inspection and assessment is based on a condition rating method, whereby the inspectors go to the bridge and assign a condition rating to the major components of the bridge. The rating of the entire bridge is based on the conditions of all of the elements no matter the relative importance of the elements. This approach, while easier to collect data, does not recognize that the nature and location of damage on an element, and the type of element, will greatly change the reliability of the overall structure. Frangopol et al. describe a reliabilitybased approach for managing highway bridge maintenance and claim that this approach could cost at least 50% less than conventional maintenance strategies if labor and user costs are considered (Frangopol et al., 2001). This reliability-based approach will require that a greater amount of condition information be collected from bridge elements. The location and amount of damage for all elements will have to be determined so that the relationship of the damage to the reliability of the elements and to the bridge can be assessed.
