System identification of Burbank six-story building using earthquake data

This paper examines the problem of identifying the dynamic characteristics of an instrumented building using an input-output system identification method. The building studied was a six-story steel moment-resisting frame (SMRF) instrumented by the California Strong Motion Instrumentation Program (CSMIP). The building was shaken by several earthquakes and strong motion data of the building response was recorded during these earthquakes and were made available through SMIP. In particular the Whittier Narrows (October, 1987), the Sierra Madre (June, 1991) and the Northridge (January, 1994) earthquakes were considered in the studies reported here. The seismic performance of steel moment-framed buildings has been of particular interest after the 1994 Northridge earthquake because brittle fractures were discovered at the beam-column connection. The Eigensystem Realization Algorithm with Data Correlation (ERA/DC) and Observer/Kalman filter Identification (OKID) were used in these studies for system identification purposes. The identified modal properties of the structure were compared and verified with the spectral analysis of the response of the structure excited by three different earthquakes