The use of pretensioned concrete beams in bridge superstructures has increased dramatically in the past 30 years. At the same time, strength reduction factors and load limits have been increased, effectively reducing load margins for existing bridges. As a result, the limit state of fatigue failure is now a more important consideration in the evaluation of existing bridges and the design of new bridges. At the present time, engineers have few guidelines to follow for fatigue design of pretensioned concrete members.
