Many state departments of transportation employ life-cycle cost analysis in their highway bridge-management systems as a means of decision-making in maintenance, rehabilitation, and replacement. Life-cycle cost analysis is based on the concept of discounted cash-flow analysis. The authors of this technical paper present a brief review of current methods for life-cycle cost analysis implementation, and based on that review, identify key factors that influence life-cycle cost analysis. The value index model is introduced, which considers bridge age, condition rating, and cost--the most critical factors in the decision-making process. The value index parameter incorporates these variables for the optimization strategy. This allows rational decisions to be made regarding the type of work to be performed that best suits a bridge's needs within the appropriate constraints. The "objective function," or the function to be optimized, is written in terms of the key factors that control the decision-making process. The method is demonstrated in several case studies for highway bridges in Illinois. Also discussed is the significance of certain limits imposed on the key factors in the optimization process and the various options that can be selected within these limits. Although the proposed model is suggested for project-level analysis, it can be extended for use in a network-level analysis as well. This application, however, necessitates development of a separate allocation-of-fund process that in turn needs input from the bridge engineer and information on the individual bridges in the network in terms of their needs and priorities for rehabilitation, repair, or replacement.


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  • Accession Number: 00711539
  • Record Type: Publication
  • Files: TRIS, ATRI
  • Created Date: Sep 14 1995 12:00AM