Project Title	Life Extension of Fatigue-Damaged Highway, Rail, and Transit Bridges: Identifying Actual Crack Tip
University	Lehigh University
Principal Investigator(s)	Stephen Pessiki (PI, Lehigh), Richard Sause (Co-PI, Lehigh), Ian Hodgson (Co-PI, Lehigh)
PI Contact Information	spp1@lehigh.edu
Funding Source(s) and Amounts Provided (by each agency or organization)	Federal Share — $162,650 Match — $162,650
Total Project Cost	$325,300
Start and End Dates	8/1/20—7/31/22
Brief Description of Research Project	This project has two objectives: (1) to investigate the potential for a fatigue crack to initiate from the stress concentration from a crack-arrest hole combined with the stress concentration from the fillet weld toe, and provide recommendations to prevent such crack initiation; and (2) to assess the reliability of non-destructive evaluation (NDE) methods to identify the location of the crack tip, for a fatigue crack at a fillet weld toe, and provide recommendations on appropriate NDE methods for this application. For the situation shown above, a fatigue crack growing vertically at a fillet weld toe, is common, and crack-arrest holes are a common repair method. Therefore, the project addresses a significant problem of practical value, with the potential to help State DoTs and other bridge owners to reliably repair fatigue cracks. The potential impacts of more reliable fatigue crack repair are reductions in cases where a previously repaired bridge is fully or partially closed as additional expensive emergency repairs are made. This project fits within both the Application of Innovative Materials and Technologies thrust and the Condition Assessment and Health Monitoring thrust of CIAMTIS.