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Advances in Civil Engineering
Volume 2012 (2012), Article ID 402179, 10 pages
Research Article

Dual Mode Sensing with Low-Profile Piezoelectric Thin Wafer Sensors for Steel Bridge Crack Detection and Diagnosis

1Department of Mechanical Engineering, University of South Carolina, Columbia, SC 29208, USA
2Mistras Group Inc., 195 Clarksville Road, Princeton Junction, NJ 08550, USA
3Department of Civil Engineering, University of South Carolina, Columbia, SC 29208, USA

Received 30 May 2011; Accepted 6 September 2011

Academic Editor: Piervincenzo Rizzo

Copyright © 2012 Lingyu Yu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Monitoring of fatigue cracking in steel bridges is of high interest to many bridge owners and agencies. Due to the variety of deterioration sources and locations of bridge defects, there is currently no single method that can detect and address the potential sources globally. In this paper, we presented a dual mode sensing methodology integrating acoustic emission and ultrasonic wave inspection based on the use of low-profile piezoelectric wafer active sensors (PWAS). After introducing the research background and piezoelectric sensing principles, PWAS crack detection in passive acoustic emission mode is first presented. Their acoustic emission detection capability has been validated through both static and compact tension fatigue tests. With the use of coaxial cable wiring, PWAS AE signal quality has been improved. The active ultrasonic inspection is conducted by the damage index and wave imaging approach. The results in the paper show that such an integration of passive acoustic emission detection with active ultrasonic sensing is a technological leap forward from the current practice of periodic and subjective visual inspection and bridge management based primarily on history of past performance.