Suspension bridge vibration measurement using multihop wireless sensor networks

Abstract Wireless smart sensor networks (WSSNs) have been expected to improve the capability to capture structural dynamic behaviors through dense instrumentation as well as to evaluate the current condition of structures. While the expectation for structural health monitoring using WSSNs has been high, among the key limitations are the limited radio communication range and communication speed. A multihop communication protocol addressing these issues has recently been proposed. Its throughput does not decrease as the hop number increase while similar protocols in the past suffer from significant decrease in speed. Employing this protocol, a wireless sensor network system has been developed to measure structural vibrations. This system first synchronizes all the sensor nodes using multihop RF communication. Based on synchronized clocks, each sensor node records structural vibration and save data on its local storages. The data is then transferred to the base station over multihop routes promptly. This system is installed on a suspension bridge and traffic induced vibrations of the main girder are measured. This monitoring campaign demonstrates quick and easy installation, measurements, and sensor removal as well as its capability to capture dynamic behavior of the bridge. This paper describes the developed monitoring system and the one-day monitoring campaign, which demonstrate the effectiveness of the multihop system.