Bridge Management Using In-Service Data (Phase II)

Effective bridge management can aid in determining resource allocation and help a DOT in cost-effectively maintaining its inventory of bridges. The current methods used have inherent limitations: the use of as-built conditions and design capacities yields ratings that may be overly conservative, while full-scale load tests yield accurate data but are costly and require closure to traffic. The researchers used an in-house-developed In-Service Bridge Monitoring System (ISBMS) to collect data that was then used to develop a load rating for the bridges studied. Using two weeks of data collected during biannual inspections of bridges, a two-week rating for each bridge in the study was developed. This two-week rating was compared to the 50-year rating that is usually calculated for bridges based on design capacities. The study showed that the two-week rating factors are, for the most part, between three and eight times greater than the 50-year rating factor. It is believed that the projected two-year rating from this data would lead to an increased rating factor in bridges. Additional work is needed to incorporate peak gauge data into the data collected by the ISBMS, enabling better prediction of the load rating stress. It would also be valuable to compare weigh-in motion (WIM) data to the stresses seen during a certain time period to help identify the average weight of trucks crossing the bridge and correlate the truck weights to the stress in the bridge. The proposed project would be a continuation of the work done in the initial bridge management project, with the focus some of these as-yet unaddressed issues.