Off-Topic: A Structurally Safe Summer Olympics
The China Earthquake Administration, the leading governmental body managing China’s earthquake preparedness and disaster mitigation, selected a structural health monitoring (SHM) solution developed by National Instruments’ (Austin, TX) alliance partner CGM Engineering Inc. (Pasadena, CA). The systems are based on National Instruments’ LabVIEW graphical system design platform and CompactRIO programmable automation controllers, and designed to aid engineers in conducting structural health research on seven recently constructed megastructures in China, including both of the main venues for the 2008 Summer Olympics-the Beijing National Stadium and the National Aquatics Center.
“The main objective of this civil engineering project is to develop a state-of-the-art solution to monitor structural health characteristics including stability, reliability and livability in real time by using contemporary computing, sensor and communication technology,” says Chris McDonald, vice president of CGM Engineering. “Our systems are designed to capture the vibrational signatures of structures and detect any sudden shifts of structural characteristics to improve structures and help reduce the loss of life and property when catastrophic events such as earthquakes, hurricanes or fires occur.”
The nine 64-channel and two 36-channel SHM systems each contain multiple CompactRIO controllers that directly connect to accelerometers for vibration measurements and an external GPS receiver for inter-chassis synchronization. Within each chassis, the LabVIEW FPGA Module is used to synchronize each measurement channel to within ±10 microseconds of the GPS-disciplined clock. The LabVIEW Real-Time Module also is used to program user-configurable filtering to prevent unwanted noise from interfering with the low-frequency measurements being acquired. Each system is encapsulated in a rugged National Electrical Manufacturers Association (NEMA) enclosure.
The SHM system performs continuous, real-time monitoring at each location, and engineers can remotely access the locally stored data from anywhere in the world via secure Internet connections. Additionally, engineers can configure the systems using either a single or multivariate architecture to send e-mail notifications when events occur.
- National Instruments