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Mid-America Transportation Center

NDOR Life Cycle Assessment of Nebraska Bridges


Researchers

  • Principal Investigator: George Morcous (gmorcous2@unl.edu 402-554-0571)
  • Project Status
    In Progress
    Abstract
    Nebraska bridge management systems (NBMS) was developed in 1999 to assist decision makers in optimizing the use of the available resources for the maintenance, rehabilitation and replacement of approximately 16,000 highway bridges across the state of Nebraska. Although NBMS was developed based on the National Bridge Inspection Standards (NBIS) and National Bridge Inventory (NBI) data items, it is different from other bridge management systems. The NBMS flow charts currently used by the Nebraska Department of Roads (NDOR) Bridge Division for selecting maintenance actions have been developed entirely based on engineering judgment without any consideration of the life-cycle cost (LCC) of the proposed actions. This may result in uneconomical decisions that are hard to justify. In addition, the deterioration rates used in predicting the future condition of bridge components and determining the optimum year of the proposed actions are entirely based on national average rates and do not represent the actual deterioration of Nebraska bridges. This may result in suboptimal timing for the proposed actions. Moreover, the formula adopted for estimating costs and the corresponding unit prices needs to be updated to reflect the actual cost incurred by the contractor in the recent years. According to the U.S. Department of Transportation, life-cycle cost analysis (LCCA) is a scientific approach that provides comprehensive means to select among two or more project alternatives (USDOT 2002). LCCA is a necessary component in bridge management systems (BMSs) for assessing investment decisions and identifying the most cost-effective improvement alternatives. NCHRP project 12-43 “Life-Cycle Cost Analysis for Bridges” has resulted in standardized procedures for conducting life-cycle costing of bridges and guidelines for applying LCCA to the repair of existing bridges or the evaluation of new bridge alternatives. The steps of this process are summarized as follows: Establish alternatives, determine timing, Estimate cost, Compute life-cycle cost and analyze results. Several studies have been carried out to estimate the deterioration rates of different bridge components and to develop models that predict their future condition. The results of these studies have revealed the wide variation in deterioration rates based on environmental impacts, traffic volume and loads, structure and material type, and maintenance practices. Therefore, the deterioration models developed for a specific group of bridges are useful only for that group and should not be generally applied to other groups
    Project Amount
    $ 37,232