Inspection of Steel Bridges for Fatigue Damage

Fatigue damage usually occurs in certain typical members and details. Armed with this knowledge, an experienced inspector can evaluate the physical condition of a structure simply, effectively and economically by periodic visual inspections, supplemented by nondestructive testing. Discovery of fatigue problems during an inspection demands prompt evaluation and action on the part of the inspector. If the inspector himself does not possess sufficient knowledge of structural behavior to determine the necessary course of action, he should recommend at once to the proper authorities that professional structural consultation be obtained. For complicated, important structures it is often desirable to make a complete fatigue stress analysis of the structure, supplemented by visual inspections and nondestructive testing. Such an evaluation gives an indication of the possible locations of fatigue damage, and helps to place in proper perspective the significance of any cracks discovered. This type of inspection is advantageous in a structure where repair work or shutdown will result in considerable inconvenience.