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Sensor network application framework for autonomous
structural health monitoring of bridges
Edward Sazonova, Kerop Janoyan b, Ratan Jhac
a Dept. of Electrical and Computer Engineering
b Dept. of Civil and Environmental Engineering
c Dept. of Mechanical and Aeronautical Engineering
Clarkson University, 8 Clarkson Ave, Potsdam, NY, 13699
ABSTRACT
Life cycle monitoring of civil infrastructure such as bridges and buildings is critical to
the long-term operational cost and safety of aging structures. Nevertheless, there is no
commonly accepted and recognized way to perform automated monitoring of bridges.
One of the important issues is the cost of the data acquisition subsystem and its
installation and maintenance costs, which are tightly connected to the choice of
monitoring methodology.
The presented application framework includes: first, Wireless Intelligent Sensor and
Actuator Network (WISAN) as an inexpensive way to perform data acquisition for the
tasks of structural health monitoring; second, a vibration-based SHM method for bridges;
and third, a fully autonomous SHM system for bridges, ambient-energy-powered and
minimally dependent of human involvement.
Design of the sensor network reflects the particularities of the application: proactive
rather than reactive nature of the data streams; fault-tolerant architecture ensuring
protection from extreme events; and real-time data acquisition capabilities. Other issues
include operating a massive array of heterogeneous sensors, achieving a low cost per
sensor, cost and sources of energy for the network nodes, energy-efficient distribution of
the computational load, security of communications and coexistence in the ISM radio
bands.
The modal SHM methods under consideration are the method of modal strain energy
with fuzzy uncertainty management, method of damage index and a method based on
Hilbert-Huang transform. Modal identification through ambient vibrations is performed
though auto-regressive moving average models.
The final step in the monitoring methods is the determination of bridge deterioration
rate and prediction of its remaining useful life based on measurements provided by the
sensor network and modal methods used. The deterioration curves are generated at both
the element and bridge levels and are compared to existing inspection-based methods.
Keywords: wireless sensor networks, structural health monitoring, ambient
vibrations, autonomous systems, modal strain energy, deterioration rate, life-cycle
monitoring.