Professor John Wallace

Current Students


Derek Skolnik


Derek Skolnik is a PhD candidate in the civil and environmental engineering program at the University of California, Los Angeles. Research interests include instrumentation development and specifications for structural health monitoring, in-field forced-vibration/ambient testing, system identification, and infinite element model updating.


Project/ Research Abstracts


System Identification and Health Monitoring Studies on Two Buildings in Los Angeles

Presented are applications of modal system identification and finite element model updating techniques utilizing data collected during earthquake and forced vibration tests of two buildings in Los Angeles. The Louis Factor building, permanently
instrumented with a 72-channel accelerometer network, is continuously recording responses to earthquake and ambient vibrations. The Four Seasons building, damaged in the 1994 Northridge earthquake, served as the pilot project of the nees@UCLA equipment site, in which hundreds of sensors were deployed to record responses to
forced vibrations from linear and eccentric mass shakers. For each structure, modal properties are identified first; and these data are subsequently used to update their initial finite element models. Novel improvements to a sensitivity-based updating
method addresses numerical difficulties associated with ill-conditioning. Predictions of updated models compare well with measured data.




UCLA Department of Civil and Environmental Engineering     5731/5732 Boelter Hall     405 Hilgard Avenue     Los Angeles, CA  90095-1593
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