Throughout its useful life, a bridge requires both routine and periodic maintenance and major rehabilitation work before being entirely replaced. Therefore, economic decisions on bridge replacement and rehabilitation need to be made with the future expenses in mind. For a life cycle cost (lcc) analysis to be realistic, three types of information must be supplied: timing, cost, and effect of bridge work. A reasonable estimate of the timing for future bridge repair workis especially critical because it strongly affects the results of lcc analysis. A statistical analysis examined the timing of various bridge activities performed by the indiana department of transportation. The analysis indicates that bridges have been replaced for various reasons when bridge life is between 40 and 70 years, with 53 years being the average. Deck replacement has been done when bridges are about 45 years old, with no previous major rehabilitation work. Deck reconstruction and overlay, the most frequently recorded rehabilitation group, has been performed when bridges are about 22 years old. Timings of occasional routine maintenance works were not determined because the maintenance records available at the time of study didnot contain specific locations of the bridges. Maintenance costs need to be included as an annual expenditure in an lcc analysis until more complete information is available. This paper appears in transportation research record no. 1268, Highway maintenance operations and research 1990.
Samenvatting