Illinois researchers have developed an inexpensive, wireless means for continuous and reliable structural health monitoring and successfully deployed their system this summer at full scale on the new Jindo Bridge in South Korea. A joint project between the University of Illinois at Urbana-Champaign, KAIST in Korea, and the University of Tokyo, it is the first dense deployment of a wireless sensor network on a cable-stayed bridge and the largest of its kind for civil infrastructure to date.
The researchers — part of the Illinois Structural Health Monitoring Project (ISHMP) led by Bill Spencer and Gul Agha — designed, developed, and tested sensors that can be manufactured very cheaply and still produce the high-fidelity data required for structural health monitoring. Their research has also produced a customizable software framework that simplifies the development of structural health monitoring applications for smart sensor platforms.
In combination, their sensors and software create an integrated framework that can be utilized by most civil engineers without the need for extensive background in electrical engineering or computer science. According to Spencer, more than 40 institutions throughout the world are now using the ISHMP framework.
"It's becoming the de facto standard for wireless sensing of civil infrastructure," Spencer said. Structural health monitoring is an emerging field that combines civil engineering knowledge with developments in sensor technology, information management, and networking technologies. The goal is to achieve a more reliable alternative to traditional structure inspection techniques. Until now, though, its usefulness was limited by concerns about cost and effectiveness.
"Manual inspection of bridges costs millions of dollars, is relatively unreliable, and can only be carried out infrequently," Spencer added.' "Some real-world structural health monitoring deployments using wired sensors have have been able to provide detailed information about the state of civil infrastructure. However, the enormous expense of installing traditional monitoring systems has significantly limited such deployments."
The Illinois team's framework addresses this issue by employing dense arrays of wireless smart sensors designed to record and transmit complex, high-fidelity data cheaply and efficiently. The team's technology employs concurrent and distributed real-time processing to overcome the limitations inherent in traditional centralized approaches.
"The traditional centralized approach for structural health monitoring is not feasible with moderate to large numbers of sensors; tremendous amounts of data must be sent to such a central station, requiring expensive, difficult-to-install wired networking and introducing a single point of failure," Agha, a professor in the University of Illinois at Urbana-Champaign Department of Computer Science (CS), explained. "Our research in distributed structural health monitoring using wireless sensor networks overcomes these problems and promises a robust, significantly lower-cost safer alternative to traditional structure inspection techniques."
Agha is Director of the Open Systems Laboratory at the University of Illinois at Urbana-Champaign, where researchers aim to overcome the challenges posed by scale, dynamicity, and resource constraints in the convergence of sensing, computing, wireless communication, and miniaturization technologies that make sensor networks a new computing environment. Characterized by the combined challenges of real-time resource management in embedded systems and large-scale coordination in distributed computing, sensor networks offer a wealth of open research problems.
Other contributors to the project include Jennifer A. Rice, Shinae Jang, Hongki Jo, Robin Kim, Sung-Han Sim, Parya Moinzadeh, and Kirill Mechitov.