Accelerated Bridge Preservation
|Keywords:||Bridge preservation, bridge maintenance, user delay costs|
This project used results of a national survey to collect life expectancies of bridge activities and the durations of construction to do those activities. The national survey also showed the current use of contractors, in-house staff and combinations to execute those activities. In addition, the national survey provided input from 11 agencies on products or processes to speed bridge preservation activities. A second survey of regional bridge engineers in Michigan provided a list of activities and timelines they would use over a 75-year period. A bridge traffic table provides input on traffic for all bridges on the Michigan system. An excel-based tool was developed to evaluate discounted bridge activity costs and user delay costs for bridges in the table. Examples show the effect of discount rate, speed limit, average annual daily traffic, region, and use of modified activity lists. The tool, and especially the use of modified activity lists, allows a region to evaluate user delay costs as well as bridge activity costs for their current practice and for adjustments to that practice. A second tool allows comparison of preservation versus no-preservation activity lists for a user supplied bridge age. Activity costs and User Delay costs are calculated for both scenarios, but decisions in the second tool are based on equivalent annual costs.