Exploring Wireless Strain Measurement for Civil Infrastructure

摘要

The federal government currently requires that all bridges be inspected every 2 years for the US National Bridge Inventory (NBI). The most common method of investigation is visual inspection. If a problem is encountered, an additional investigation is usually recommended [1]. A more complex method of investigation using a measurement-based evaluation process of structural conditions, maintenance and rehabilitation needs is known as structural health monitoring (SHM) [2]. The current state of practice of SHM incorporates many sensors covering the critical nodes of the structure. The term 'node' indicates the wireless unit that collects data from a critical location on the structure (e.g. mid-span). All of the data from these sensors are sent through an extensive array of wires and cables to a central data processor where the data are downloaded and managed. This process is effective and highly accurate, but there are many drawbacks. Many hours are spent installing all of the sensors and running a wire or a cable from each individual sensor to the data logger. The labour involved in this extensive cabling often consumes approximately 75% of the total time involved in the test and 25% of the total cost of the test [3]. Quite often an experienced engineer is required to be onsite to transfer the data from the acquisition unit to a computer for analysis.