Conceptual framework of a remote wireless health monitoring system for large civil structures

Recent advances in smart materials and structures sensor technology offer many unique opportunities to assess the structural integrity of large civil structures. However, the remote operational environment of large civil structures, such as highways, buildings and bridges, makes condition-based health monitoring for damage assessment difficult in the event of a natural disaster. During such disasters, electrical power is lost and cellular phone lines are under heavy usage. This limits the retrieval of very important sensor data. However, recent rulings by the Federal Communication Commission coupled with advances in wireless communication products have now made it possible to circumvent existing wired and cellular infrastructure to retrieve data from smart sensors remotely and more economically. This paper discusses a novel approach using smart sensors and wireless communication technology to monitor the health of large civil structures remotely. Specifically, a remote health monitoring system for large civil structures is developed using spread spectrum wireless modems, data communication software and conventional strain sensors. This system is used to monitor the loads on a laboratory test specimen with a bolted lap joint from as far away as one mile. Commands are issued from a notebook personal computer to instruct the health monitoring system to either excite the structure or acquire data from sensors mounted externally to the structure. Data from measurements made on the structure are then transmitted wirelessly back to a notebook computer for processing and analysis using damage detection algorithms.