Institute for Transportation

Interest in timber bridges has grown rapidly in recent years
as a result of new technologies in design and construction as well as advances in material manufacturing and preservative treatments. Despite these advances, little is known about the initial and life-cycle costs of timber bridges relative to those of other construction materials. The objectives of this study were to evaluate the cost characteristics of timber bridges and to compare the initial cost of timber bridge superstructures with that of bridges constructed of steel, concrete, and prestressed concrete. For timber bridges, results show a relationship between cost per square foot and bridge length, load rating, and geographic location. In general, timber bridge superstructures tended to compete with steel and concrete bridge superstructures on an initial cost basis. However, the range in cost per square foot values for all bridges varied widely. This outcome was probably due to both the high variability in these data and the relatively small sample size of the data sets for steel and concrete.