The detection of fatigue cracks in steel bridge girders has become a major problem for bridge engineers in the USA. Currently, most bridge inspection is carried out using visual methods. Visual methods are time consuming and often miss fatigue cracks hidden under paint or by other bridge members. Snooper trucks or platforms are often required so that the inspector can gain access to all parts of the bridge. This requirement adds to the expense and complexity of the inspection process and often requires that one or more traffic lanes be closed to accommodate the required equipment. In view of the above mentioned problems and that bridge inspection budgets are limited, there exists a critical need for global and semiglobal Nondestructive Evaluation (NDE) methods which can evaluate critical parts of the bridge structure rapidly and inexpensively.