Development of a Bridge Replacement Guide for County Engineers, Phase I

With over one-third of county bridges in Alabama rated as structurally deficient or functionally obsolete, and replacement funds increasingly scarce, the development of cost-effective replacement strategies is critical. To accomplish this goal, it would be helpful to know how various types of bridges and their components deteriorate, how many years they can serve, and which advantages and disadvantages they have in the area of durability performance. A critical aspect of bridge rehabilitation and replacement is to determine the most appropriate time for bridge repair and replacement. This can be done by evaluating the durability performance of various county bridges as well as establishing reasonable bridge deterioration models for them and their components. This report outlines the progress of the first year of this two-year project and gives the deterioration rates of the common bridge types located on the Alabama County road system. Specifically, seven bridge superstructure types were considered in this study along with three different deck types. The 1999 National Inspection Inventory served as the basis of development. Results from this first phase will be combined with cost data obtained from the second phase of this project with the end product of this research being a Bridge Replacement Guide for County Engineers. This initial phase has defined the bridge deterioration rates of common superstructure types.