During September 4-16, 1986, Kentucky Transportation Research Program (KTRP) personnel conducted a two-week inspection of welding operations on bascule bridge components for the Wisconsin Department of Transportation (WisDOT). Welding was performed by the Phoenix Steel Company at Eau Clair, Wisconsin. The inspection was conducted using acoustic emission (AE) monitoring on in-process welds.

KTRP investigative experience with AE weld monitoring and testing of bridges began in 1973. Since that date, KTRP has performed nine series of laboratory and fabrication shop weld monitoring tests and conducted 20 field tests of bridges using a series of increasingly sophisticated AE devices. Over the past four years, KTRP has had success with the Acoustic Emission Weld Monitor (AEWM) developed by GARD, Inc. of Niles, Illinois. That device was originally intended to monitor in-process welding operations to detect defect formation. KTRP has determined that the unit is also suitable for detecting fatigue-crack growth on in-service bridges. The operation of the AEWM and a summary of KTRP/GARD bridge experience with that device is contained in a technical paper, which is included in the Appendix.

Report Date


Report Number


Digital Object Identifier



The contents of this report reflect the views of the author who is responsible for the facts and accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the University of Kentucky or the Wisconsin Department of Transportation. The report does not represent a standard, specification, or regulation.