Prediction of WSN placement for bridge health monitoring based on material characteristics

WSN signal obstruction from various bridge components, including girders, bracings and connectors, can affect the performance and reliability of wireless communication. Although the placement of sensor nodes is essential for forming a mesh or ad-hoc network, there are no quantitative approaches related to the optimal separation distance of each node and the corresponding signal quality. This paper reports the results of an experimental evaluation of the WSN performance in the obstructed environment of a bridge structure. The performance criteria, such as thickness of bridge components, material types and location, were analyzed to determine quantitatively the packet reception rate and allowable separation distance during wireless communication. In addition, a case study was conducted to identify the practical implication that an obstructed environment degrades the communication range and WSN reliability according to the performance criteria. The results show that the WSN placement mainly depends on the material type and object thickness.