The phenomena of fatigue failure at various common structural details in steel bridges is presented with suggested improvements for future design and fabrication. Fatigue damage has resulted from large numbers of cyclic stresses at structural details which have low fatigue resistance. Procedures are presented for the estimate of live load stresses at bridge details and for the estimate of fatigue damages. Guidelines for examination of detected cracks are given, and procedures for the evaluation of crack propagation and fracture is suggested. The report provides background information on the historical development of experimental data, summarizes the theoretical and experimental treatment of structural details, and reviews the primary factors contributing to fatigue damage (A).