Low-Cost, Strong-Motion Sensor Packages to Obtain Full Spectrum Waveforms for Earthquake Early Warning and Structural Monitoring Applications
Two groups from UCSD, at Scripps Institution of Oceanography (led by Yehuda Bock, PI) and the Department of Structural Engineering (led by Jose Restrepo, Co-Investigator) conducted a series of earthquake tests at the George E. Brown Jr. NEES-UCSD Large High-Performance Outdoor Shake Table (LHPOST). Perishable data was gathered from five GPS sensor packages collocated with accelerometers on the NSF-funded BNCS five story building (CMMI 0936505) at the LHPOST. Shake table testing of this building to strong intensity ground motion presented a unique opportunity to conduct proof testing of the new sensors and to contribute to the project goals of the already-funded BNCS project by providing additional new data for studying the response of the structural and non-structural components. The experiments were run for five different earthquake scenarios on 10 days in the period April 16 Ã¢Â€Â“ May16, 2012; first with a base isolated condition and then with a fixed-base condition.
Combining the GPS and accelerometer data allowed us to measure permanent deformation at the roof of the building during the last two events, as well as accurate 200 Hz dynamic displacements for all experiments. Excellent results overall, with some issues due to reduced satellite visibility at two of the GPS sensors. The final results were distributed to the BNCS investigators for further analysis. The results of the analysis show that there will be an order of magnitude improvement in rapid earthquake magnitude estimation from geophysical monitoring networks instrumented with GPS and accelerometers, and very early structural damage detection for structures such as tall buildings, dams and bridges.
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