Multi-Purpose Wireless Accelerometers for Civil Infrastructure Monitoring

A new wireless MEMS accelerometer sensor board is designed to meet the specific hardware and software requirements of structural engineering applications. The board has four channels of accelerometers in two directions and one thermometer. It is compatible with Mica devices for control and communication, which in turn support TinyOS as their operating system. Hardware components are designed to detect a range of vibrations of a civil infrastructure from low-amplitude ambient to earthquake strong motions. Software components are added to the general framework of TinyOS to support aggressive sampling rates and reliable communication of the measured signals. As a preliminary prototype field test, the boards have been installed on a footbridge over highway I-80 at Berkeley, CA, to measure ambient vibrations of the bridge and wirelessly communicate the signals to a base station. The collected data is then processed and analyzed and modal properties of the bridge are computed.