National Instruments Alliance Partner, CGM Engineering has developed a structural health monitoring system based on the former’s LabVIEW graphical design platform and CompactRIO programmable automation controllers. Selected by the China Earthquake Administration (CEA), the system will be used to conduct 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 Centre. Essentially, it captures the vibration signatures of structures and detects any sudden shifts of structural characteristics.
The nine 64-channel and two 36-channel SHM systems each contains multiple CompactRIO controllers with multiple accelerometer inputs. An external GPS receiver is used for inter-chassis synchronisation, and a LabVIEW FPGA Module is used within each chassis to synchronise each measurement channel to within ±10us of the GPS-disciplined clock. The LabVIEW Real-Time Module is also used to programme user-configurable filtering to prevent unwanted noise from interfering with the low-frequency measurements. Stored data can be retrieved from anywhere in the world via secure Internet connections.
In addition to the Olympic venues, SHM systems are also being used to monitor other structures, including the 104-storey World Trade Centre in Shanghai, the 66-storey Park Hyatt Hotel complex in Beijing, a 240m concrete arch dam in Ertan, an 8,266m cable-stayed bridge in Shan-Tou and the base-isolated CEA data centre in Beijing.