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Laboratory and Field Test Results for an Ultrasonic Applied Stress Measurement Instument



P A. Fuchs, A V. Clark, M G. Lozev, U Halabe, P Klinkhachorn, S Petro, H GangaRao


The measurement of applied stress on bridges can provide valuble information on the condition of the structure. The conventional technique for applied stress measurement is with a strain gage. However, strain gages can be time consuming to install because surface preparation is usually required. On a bridge, paint remocal will most likely be necessary as part of this surface preperation. When dealing with lead-based paints, which are considered hazardous waste, many time consuming removal procedures are required. Because of these factors, a device that measures applied stress without requiring paint removal could be useful. While a clamp-on strain gage can be used to measure applied stress without requiring pain removal, this type of strain gage cannot be used on some bridge details, such as webs of I-beams and top of box girders. An ultrasonic technique using non-contrast electromagnetic transducers provides a possible method for applied stress measurement which is not limited by the same factors as conventional strain gages. The transducers operate through nonconductive and conductive (lead based) paint and work on rusted, pitted surfaces. Our previous research developed a technique for the measurement of applied stresses on bridges with EMATs and included many laboratory tests. This paper describes field applications of the technique on actual bridge structures as well as additional system testing and instrument calibration in the laboratory.
Journal of Nondestructive Evaluation


bridges, EMATs, stress, ultrasonics


Fuchs, P. , Clark, A. , Lozev, M. , Halabe, U. , Klinkhachorn, P. , Petro, S. and GangaRao, H. (2021), Laboratory and Field Test Results for an Ultrasonic Applied Stress Measurement Instument, Journal of Nondestructive Evaluation (Accessed June 21, 2024)


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Created October 12, 2021