A Piezoelectric Film Type Scour Monitoring System for Bridge Pier

• Published in: Advances in structural engineering Vol. 15; no. 6; pp. 897 - 905
• Main Authors: Wang, Chung-Yue, Wang, Hao-Lin, Ho, Chun-Che
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.06.2012
• Subjects: Bridge piers; Bridges (structures); Electric potential; Piezoelectric films; Piezoelectricity; Scouring; Sensors; Voltage; monitoring; soil-water interface; piezoelectric; bridge pier; scour
• ISSN: 1369-4332; 2048-4011
• DOI: 10.1260/1369-4332.15.6.897

An upgraded piezoelectric film type real-time scour monitoring sensor installed along the bridge pier is presented. The core idea of developing this scouring sensing system is based on the physical characteristic that output voltage can be generated as the piezoelectric film is deformed by the flowing media. Therefore, a sensing device can be constructed by mounting piezoelectric thin films along the rod at a fixed distance and inserting them into a guide rail beside the bridge pier. The piezoelectric film embedded in the soil of the riverbed is undisturbed and the output voltage is much smaller than the one disturbed by the water current. From the output signals of all the piezoelectric sensors with known locations along the depth of the pier foundation, one can trace the variation of the soil/water interface before, during and after a flood. Compared with other types of scouring sensors, this piezoelectric type scouring sensor is durable, sensitive, and cost effective and works in real-time without the need for power. In this paper, a signal processing technique and performance tests in laboratory of this novel piezoelectric film type scouring device are introduced first. The installation and performance of the system in the field is also addressed.