A Hierarchical Model and Analysis of Factors Affecting the Adoption of Timber as a Bridge Material

The Analytical Hierarchy Process was used to characterize the bridge material selection decisions of highway engineers and local highway officials across the United States. State Department of Transportation engineers, private consulting engineers, and local highway officials were personally interviewed in Mississippi, Virginia, Washington, and Wisconsin to identify how various factors determine their choice of a bridge material. The Analytical Hierarchy Process was used to quantify this subjective data and to model the selection decision for different groups of decision-makers. Prestressed concrete was the material of choice in the majority of cases. This was followed by reinforced concrete, steel, and timber. Local highway officials chose timber more often than did either group of engineers. These results indicate that timber will remain a niche market for bridge applications.