Abstract
The report details the results of a study on the various methods of strengthening highway bridges. Innovative ideas for bridge strengthening were considered along with established methods which are all identified, described and categorized in the manual. Such methods considered are broadly categorized as member replacement, stiffness modification, member additions, and post-stressing. The types of structures considered to show the greatest need for the application of cost-effective strengthening methods are steel stringer bridges, timber stringer bridges and steel-through-truss bridges. Procedures are developed and outlined for selecting the most cost-effective method of strengthening each type of structure.