Seismic Response of a Tower as Measured by an Integrated Rtk-gps Sytem

Monitoring structural response induced by seismic waves is an efficient way to mitigate the damage of earthquakes. For example, the measured signal can be used to activate an alarm system in order to evacuate people from an endangered building, or to drive a control system to suppress earthquake-excited vibrations so as to protect the integrity of the structure, or to assess post-seismic damage to a structure. Traditionally such vibrations have been measured solely by accelerometers. However, it is impossible to measure the static and semi-static components of the movement with accelerometers. An integrated system combining RTK-GPS and accelerometers has been deployed atop a 108m tall tower in Tokyo in order to monitor its structural integrity on a continuous basis. Data acquired during earthquakes are automatically archived.