Distortion-induced fatigue has been a primary research topic in the Fatigue and Fracture research group at the University of Kansas, with an aim of determining the efficacy of several different retrofit measures to halt crack growth. Girder subassemblies were chosen for study to evaluate for the effectiveness of various retrofits using both an analytical approach and physical experimentation. This thesis is organized into four chapters. The first three chapters describe the analytical and experimental programs used to evaluate the uses of a composite block retrofit, a carbon fiber reinforced polymer (CFRP) retrofit, and crack-arrest holes to effectively repair distortion-induced fatigue cracking on 3-m (9-ft) steel girder segments under fatigue loading. The fourth chapter details a literature review and an analytical study of a retrofit to repair distortion-induced fatigue damage at floorbeam-to-stringer connections.