Development of a prioritization methodology for maintaining Virginia's bridge infrastructure systems

The US bridge infrastructure, an essential element to the transportation network, has been steadily deteriorating. Due to substandard levels of maintenance, bridges now pose serious risks to citizens. The American Society of Civil Engineers (ASCE) estimates that an investment of 2.2 trillion dollars would be required over a five year horizon in order to upgrade the nation's infrastructure to good condition. A portion of this large investment must be appropriated to the maintenance of bridges, which received a mediocre grade in the ASCE infrastructure scorecard-26% of bridges are either structurally deficient or functionally obsolete. These shortcomings motivate the need to improve the process for allocating resources for bridge maintenance. The team studied local infrastructure concerns by working with the Virginia Department of Transportation (VDOT). To address a reasonable level of scope, the team focused on a subset of the 16,000 total bridges in Virginia by focusing on the 383 bridges within the Hampton Roads District (HRD). The HRD has one of the highest concentrations of critical bridges in Virginia, in addition to unique economic and geographic characteristics. These factors make the HRD a suitable testbed candidate for analysis. The project, which is part of the Long-Term Bridge Performance Program, utilizes statistical and probabilistic risk analysis tools to develop a three phase bridge prioritization methodology. In Phase One, the team identified critical attributes for evaluating bridges, such as average daily traffic and sufficiency rating. Phase Two involves bridge evaluations based on the attributes identified in Phase One. In Phase Three, the team developed a technical manual detailing the proposed prioritization methodology. The methodology was demonstrated through a case study of HRD bridges. For many years, bridge data and related information on vehicle occupancy have been collected and itemized in databases such as the National Bridge Inventory (NBI) and Archived Database Management System (ADMS). The team organized the Phase One attributes according to maintenance, economic, and political components through adaptations of the Risk Filtering, Ranking, and Management (RFRM). Maintenance components were derived from the NBI fields pertaining to reliability in order to assess the structural integrity of bridges. Economic components incorporated traffic and demographic data, facilitated by geographic information systems and probabilistic analysis, to evaluate the importance of the bridges in supporting HRD's regional economy. Political components were based on bridge maintenance guidelines and data gathered from interviews with VDOT as well as HRD Manuscript received April 6, 2008. This work was supported in part by the Virginia Department of Transportation and the Virginia Transportation Research Council. Jonathan Gokey, Nathaniel Klein, Christopher Mackey, Joost Santos, Avinash Pillutla and Scott Tucker are with the Systems and Information Engineering Department, University of Virginia, Charlottesville, VA 22904. bridge engineers. The integration of maintenance, economic, and political components served as a foundation for developing prioritized portfolios of bridges, which was supported by trade-off and sensitivity analyses. The team developed a report to help VDOT decision makers allocate their maintenance budget effectively. The report consists of a detailed methodology for prioritizing bridges and a case study analysis of the HRD bridges. The resulting methodologies and techniques developed in this study can be generalized to a broad range of infrastructure systems.