BRIDGE FATIGUE DAMAGE EVALUATION AND UPDATING USING NONDESTRUCTIVE INSPECTIONS

A method is proposed to mitigate fatigue damage using information from non-destructive inspections. In spite of improvements in the design o f fatigue-sensitive structures, periodic non-destructive inspections a re still required by the profession. A linear elastic fracture mechani cs-based reliability model is proposed which incorporates uncertaintie s from many different sources, including uncertainty in the results ob tained from the non-destructive inspections. Regardless of whether or not it detects any cracks, each inspection provides additional informa tion and the underlying fatigue reliability needs to be updated after each inspection. The updated information on the reliability can be use d as a decision making tool as what to do next, in terms of whether to do nothing, reschedule the next inspection at an earlier date, or rep air or replace the structure immediately. The application potential of the method is demonstrated with the help of examples. It is shown tha t the proposed method is much superior to the current S-N curve-based AASHTO method and can be used as an alternative to it.