REAL-TIME MONITORING OF DRIFT FOR OCCUPANCY RESUMPTION
At selected locations of instrumented structures, real-time displacements are acquired by either double integration of accelerometer time-series data, or differential GPS with high sampling ratios deployed at roofs of tall buildings. Thus, sensor data is related to performance level and health of a building. Drift ratios are computed as the parametric indicator of damage condition of a structure. Several levels of threshold drift ratios can be postulated in order to make decisions for inspections and/or occupancy. Drift ratio is computed using relative displacement between two floors computed from accelerometers strategically deployed at select number of pairs of consecutive floors. However, GPS-measured relative displacements are limited to being acquired only at the roof with respect to its reference base yielding only average drift ratio for a building. Until recently, GPS systems available were limited to 10-20 samples per seconds (sps) capability limiting their use only to long-period structures (T>1 s). Most recently, up to 50 sps differential GPS systems readily available are successfully used (Panagitou et al, 2006, Restrepo, pers. comm.. 2007) thus enabling future usefulness of GPS to all types of structures. Experience with data acquired from both accelerometers and GPS deployments indicates that they are reliable and provide pragmatic alternatives to alert the owners and other authorized parties to make informed decisions and select choices for pre-defined actions following significant events. Furthermore, recent adoption of such methods by financial and industrial enterprises is testimony to their viability.
Drift ratio occupancy damage indicator accelerometer displacement GPS
M. Celebi
Research Civil Engineer and Manager of Structural Monitoring, USGS,345 Middlefield Road, Menlo Park, CA., USA
国际会议
14th World Conference on Earthquake Engineering(第十四届国际地震工程会议)
北京
英文
2008-10-12（万方平台首次上网日期，不代表论文的发表时间）