Wireless Structural Monitoring of the Geumdang Bridge using Resolution Enhancing Signal Conditioning

Field deployment of wireless sensors is a necessary first-step towards validating their performance within the complex and challenging environments posed by civil structures. In this study, a wireless structural monitoring system, assembled from low-cost wireless sensor prototypes, is deployed upon the Geumdang Bridge, Korea. The wireless monitoring system is installed on the concrete box girder bridge on two separate occasions. During the first installation, the wireless system is shown to be capable of collecting acceleration response data using a network of fourteen wireless sensors. However, higher than expected noise is observed in the sensor data. To improve the resolution of the wireless monitoring system, a signal conditioning circuit is proposed for band-pass filtering and amplification of accelerometer outputs before connecting to the wireless sensors. With the signal conditioning circuit greatly enhancing the resolution of the wireless monitoring system, the Geumdang Bridge is again utilized for validation. During this phase of the study, response data collected by the wireless monitoring system is compared to that collected from a traditional wired monitoring system. The result is high-resolution data that can be used to accurately identify modal frequencies and mode shapes of the bridge. INTRODUCTION Wireless sensors have been proposed for use in structural monitoring and structural health monitoring systems. Wireless sensors are particularly attractive for civil structures because they eliminate the need for extensive lengths of coaxial wires common to traditional monitoring systems. To date, a number of academic and commercial wireless sensor platforms have been proposed for structural monitoring [1-4]. The wireless sensors proposed are all designed with three major functional components. First, to collect data from sensors SOURCE: Jerome P. Lynch, Yang Wang, Kennth J. Loh, Jun Yi, and Chung-Bang Yun, " Wireless Structural Monitoring of the Geumdang Bridge using Resolution Enhancing Signal Conditioning ," Proceedings of the 24th International Modal Analysis Conference (IMAC XXIV), St. Louis, MO, January 30 February 2, 2006