Bridge preservation activities have focused on the service life extension of bridge components or protection systems that extend the useful life of bridges. National efforts are underway to look at materials, design and construction practices to extend the useful life of bridges toward an elusive 100 year mark. Informal research done by the Transportation Research Board Bridge Preservation Committee (AHD037) using 20 years of National Bridge Inventory data for all states in the United States indicates that the majority of bridge replacements may not be driven by the condition of the bridge. If the majority of bridges are not being replaced due to condition, then what is driving bridges to be taken out of service? Are bridge preservation efforts appropriately focused on the true factors that are leading to the premature replacement of bridges? Understanding what is causing bridges to be decommissioned will allow bridge managers to better adapt practices to achieve the maximum possible service life.

The objective of this research project was to determine the driving causes of bridge decommissioning in the United States.