In-situ Health Monitoring on Steel Bridges with Dual Mode Piezoelectric Sensors

Current routine inspection practices for bridge health monitoring are not sufficient for timely identification of areas of concern or are incapable of providing enough information to bridge owners to make valuable informed decisions for maintenance prioritization. Continuous monitoring is needed for long-term evaluation from an integrated sensing system that would act as a monitoring and early warning alarm system that is able to effectively communicate the information from the bridge directly to the bridge owners for potential and immediate response. Due to the variety of deterioration sources and locations, currently there is no single NDE method that can detect and address the potential sources globally. To address the need of this urgent highway bridge health monitoring, a joint venture research has been initiated under the NIST Technology Innovation Program by incorporating a novel and promising sensing approach based on piezoelectricity together with energy harvesting to reduce the dramatic uncertainty inherent into any inspection and maintenance plan. One approach to damage detection and classification has been focused on the use of piezoelectric sensors (PES) at both active (ultrasonic NDE) mode and passive (acoustic emission) mode on steel bridge. The acoustic emission (AE) method has been shown the best potential for global bridge health monitoring while active sensing will provide additional quantification process. Two types of the PES have been studied to provide fundamental principles for their applications to steel bridges. Extensive laboratory investigation was performed supported by a theoretical modeling analysis.