The objective of this research was to identify and evaluate welding methods for repair of cracked steel bridge members to restore their load carrying capacity and fatigue life. The research included a synthesis of existing information on welding repair procedures including an identification of the problems and solutions for repair welding of members while under traffic loading. Laboratory and field tests were performed to evaluate the proposed guidelines for welded repair of cracked steel members, and a manual of recommended practice was developed.

Research has been completed and the final report published as NCHRP Report 321, "Welded Repair of Cracks in Steel Bridge Members." The report is presented in the form of a manual of recommended practice for repair welding and includes criteria for welder qualification and specific repair procedures depending on the type and location of cracks.