Innovative sensing for real-time health monitoring of geostructural systems

Abstract

Recent advances in miniaturizing sensors and electronics and the development of a pervasive wireless infrastructure have enabled a paradigm shift in the health monitoring of soilstructure systems. Created by researchers at Rensselaer Polytechnic Institute (RPI)1 and Measurand Inc.,2 the wireless ShapeAccelArray (SAA) sensing system is capable of measurements that represent a significant advance in implementing this shift. Over the last 50 years engineers have used traditional, manual slope inclinometers to monitor the health of landslides and construction activities. However, the frequency and accuracy of this labor-intensive monitoring rely on a trained engineer manually collecting and managing the data. The low sensor density provided by this method results in very limited data. State departments of transportation and federal agencies continue to spend significant resources monitoring possible slope failures using manual inclinometers or in-place inclinometer arrays. The expense and inflexibility of the slope inclinometer arrays, and the need for torsional alignment, make installation of multiple setups at a single site relatively rare, severely limiting the ability to conduct pervasive real-time monitoring. The wireless SAA system can remotely collect both 3D deformation and acceleration readings anywhere there is cell-phone coverage. The SAA system enables gravity-based shape calculation along a sensorized substrate through an extension of technologies that use fiber-optic orientation sensing to calculate 3D polylines representing the shape of a sensor array.3 The SAA uses microelectromechanical systems (MEMS) accelerometers in a precalibrated, geometrically constrained arrangement4 to provide long-term stability previously unattainable with fiber-optic Figure 1. Advancing polyvinyl chloride casing segments along the wireless ShapeAccelArray (SAA).