This Small Business Innovation Research Phase II project addresses the deteriorating situation with respect to our nation?s infrastructure system, particularly bridges. A solution is critically needed to monitor the structural integrity of such systems in order to identify potential failures ? such as the Minneapolis I-35W Bridge collapse ? before they occur. Existing solutions for structural state sensing are expensive, labor intensive, non-scalable, and unreliable. Phase I demonstrated the feasibility of an innovative, cost-effective, non-intrusive, and scalable structural monitoring technology known as Active RF Test (ART). The investigators developed a prototype of a thin, mechanically flexible, patch-like wireless sensor that can be easily attached to distributed points of a structure. ART sensors are batteryless, with their energy supplied through an in-network RF energy radiation mechanism. Based on the Phase I success, Phase II will (1) optimize the architecture and enhance the capabilities of the ART sensors; (2) develop cost effective processes for high-volume production of the sensors; (3) develop analytical tools that generate a map of installation locations for ART sensors on a structure; (4) develop detection/diagnostics models based on the sensors; and (5) conduct a field evaluation of the ART system on two highway bridges.
The broader impact/commercial potential of this project is protecting the US infrastructure against aging, structural malfunction, and failures. Aging infrastructure poses a significant societal challenge: recent reports indicate that the US transportation infrastructure has 601,027 bridges, of which 71,419 are structurally deficient. Unique features of the proposed ART technology ? such as easy installation, low cost, scalability, energy self sufficiency, and durability ? make it an ideal response to this challenge. The attachment of ART patch sensors will be non-intrusive to a structure, the installation effort will be minimal, and no drilling will be required. The mechanical flexibility of the ART patch sensors will allow adaption to complex geometries, including bearing plates, gusset plates, joints, support cables, and truss systems on a bridge. Finally, ART technology features a multipurpose solution that can be tailored to structural integrity monitoring needs of different types of structures, including bridges, pipelines, dams, airframes, and offshore platforms. The 71, 419 structurally deficient US bridges alone represent a commercial market of $2.8 billion. The potential to address other structures, along with the potential for international sales, would enhance the opportunity.
Deterioration of critical infrastructure - such as bridges, pipelines, and railways - due to structural malfunction, aging, and natural distress is a common, yet sophisticated problem. Protecting infrastructure systems against such phenomena can be very complex and costly. Visual inspection of structures done by experts has often been the most commonly used remedy. For example, mandated bi-annual inspections of bridges are used for integrity monitoring. Visual inspections, however, have proven to be insufficient to ensure safety of the infrastructure as many structural issues can initiate, develop, and progress between two inspections of an aged structure. Therefore, manual inspection cannot prevent catastrophic failures such as the fatal Minneapolis I-35W Bridge collapse in August 2007. Beyond manual inspections, other existing techniques for structural health monitoring suffer from non-scalability due to the high cost of instrumentation devices, high installation costs (e.g., due to wiring needs), or high maintenance costs. Public safety and the continuous serviceability of structures require cost effective, easy to use, and reliable technologies that regularly assess their structural health and integrity. In this project, Resensys has developed a remote sensing technology for real-time monitoring of structural integrity of infrastructure systems. The Resensys solution improves the overall cost of maintenance and operation of a bridge; it also provides the convenience of anytime, anywhere access to the live stream and archived traces of data collected by sensors. In addition, the continuous data collection of the structure allows around-the-clock knowledge of the infrastructure’s health status. Another important advantage of the Resensys solution is being ultra-low-power and low maintenance, which enables the sensors to operate for decades with a very small coin cell battery, or even without a battery by utilizing energy harvesting. Finally, Resensys sensors are small and easy to install. Average installation time of a sensor is less than a minute. To provide a maintenance free sensing platform, Resensys’s technology has combined a number of recent and emerging technologies – microstructured sensing, ultra-low-power wireless communication, and advanced microelectronics – into a novel, small, lightweight, adhesive-mount, and ultra-energy efficient processing wireless device known as SenSpot. This device is built based on Resensys’s Active RF Technology (ART), which offers a high performance method for large-scale sensing, wireless synchronization, and ultra-low power wireless communication. SenSpot technology allows measuring variety of structural health parameters. These parameters include strain, acceleration, displacement, deformation, vibration, tilt, inclination, humidity, temperature, etc. Resensys solutions have been deployed and evaluated in multiple national and international projects. In addition to bridges, Resensys technology can be used to monitor other infrastructure systems. Examples include: pipelines, airplanes, buildings, tunnels, dams, towers, etc. Currently, Resensys monitoring systems has been deployed on several major structures, including major highway bridges on US roads and Interstate Highways, tunnels, airplanes, and commercial buildings. In the US, Resensys systems have been in use to monitor highway bridges or other structures in Washington DC, Maryland, Georgia, Illinois, and California. Outside the US, Resensys has monitoring systems in Canada, Japan, Singapore, Indonesia, and New Zealand.
