Consequence-based management of North American railroad bridge networks enabled by wireless smart Sensors

North American railroads are exploring means to improve the management of their bridge networks to increase overall profitability. Current maintenance, repair, and replacement (MRR) decisions are informed by bridge inspections and ratings, which recommend observing the response of bridges under trains. However, an objective relationship between bridge responses, bridge service state condition, and the associated impact to railroad operations has yet to be established. If the consequences of MRR decisions could be better determined, then the railroads could more cost-efTectively allocate their limited resources. This paper develops an approach for consequence- based management of railroad bridge networks, adopted from the field of seismic risk assessment, for making MRR decisions on a network-wide basis. The proposed framework employs fragility curves to relate service condition limit-states to transverse displacement caused by traffic. The operational costs associated with these service conditions can be used to estimate the total costs of a given MRR policy. In this way, optimum MRR decisions minimize the total network costs. Additionally, measured bridge data can be used to update periodically the fragilities. This framework provides a consistent approach for the prioritization of railroad bridge MRR decisions.