International Collaboration to Develop a Structural Health Monitoring System Utilizing Wireless Smart Sensor Network and Its Deployment on a Cable-stayed Bridge

Wireless smart sensors (WSS) equipped with on-board computation and wireless communication capabilities are expected to provide rich information for structural health monitoring (SHM). While a large number of researchers have been contributing their efforts toward the realization of wireless smart sensor networks (WSSN), full-fledged implementation of WSSN for SHM has not yet been materialized. WSSN systems for SHM involve various research fields and require understanding in respective areas. Therefore, collaboration among researchers plays an important role in pursuing this inter-disciplinary research. Recent prevalence of inexpensive telecommunication systems facilitates close collaboration among international research groups. The authors in Japan, Korea, and the U.S. with respective research strengths have been closely collaborating in WSSN development and its deployment on a cable-stayed bridge in Korea. This tri-lateral collaboration involves frequent teleconferences to coordinate research efforts, system component development in each group, and joint visits to the bridge site. Seventy WSS have been installed on the bridge. The dynamic behavior of the girder, cable, and pylons were remotely observed and recorded over the internet. The sensor operational conditions such as battery voltage have also been monitored. Obtained data sets have been analyzed among the three groups and were fed back to system developments. Introduction Wireless smart sensors equipped with computational and wireless communication capabilities are expected to provide rich information for structural health monitoring (SHM). Inexpensive nature of sensors nodes and wireless communication allow dense sensor instrumentation over structures. Densely instrumented sensors can capture large structures’ dynamic behaviors in detail in the space domain. Investigation of dynamic characteristics from spatial perspectives has been pursued for SHM; mode shape curvature and mode shape phase, for example, are considered to reflect structural conditions (Pandey et al 1991; Nagayama et al. 2005). Furthermore, there are a variety of damage detection algorithms assuming 5WCSCM-045