000011891 001__ 11891
000011891 005__ 20141205155957.0
000011891 04107 $$aeng
000011891 046__ $$k2008-10-12
000011891 100__ $$aTodorovska, Maria I.
000011891 24500 $$aIdentification of Fixed-Base and Rigid Body Frequencies of Vibration of Soil-Structure Systems from Recorded Response with Minimum Instrumentation

000011891 24630 $$n14.$$pProceedings of the 14th World Conference on Earthquake Engineering
000011891 260__ $$b
000011891 506__ $$arestricted
000011891 520__ $$2eng$$aCivil engineering structures are founded on soils, which are not infinitely rigid, and alter the structural dynamic response by modifying its frequencies of vibration and introducing additional degrees of freedom and dissipation. The energy of the vibrational response of the coupled soil-structure system is concentrated around the frequencies of vibration of the system, which depend on the properties of the soil, structure and foundation. Consequently, observed changes in the frequencies of vibration, as identified via Fourier type of analyses, can be due to changes in any of these quantities. For structural health monitoring, it is essential to be able to isolate the changes in the fixed-base frequencies - task thought to be impossible unless the structural instrumentation had been specially designed, which is not the case for most instrumented structures. This paper shows how the fundamental fixed-base frequency of a structure deforming primarily in shear can be measured, using impulse response functions, and then the rigid body rocking frequency can be computed using a relationship between fixed-base, rigid-body and system frequencies. This requires data from only two sensors recording horizontal motion - at ground level and at the roof. Results are shown for the NS response of Millikan Library in Pasadena, California, during several earthquakes between 1970 and 2003, which reveal to which degree the observed “wonder” of this building NS system frequency has been due to structural deterioration vs. nonlinear elastic behavior of the building and nonlinear behavior of the foundation soil.

000011891 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb.
000011891 653__ $$aStructural health monitoring, structural identification, fixed-base frequency of vibration, impulse response analysis, soil-structure interaction, rigid body frequency of vibration, Millikan library.

000011891 7112_ $$a14th World Conference on Earthquake Engineering$$cBejing (CN)$$d2008-10-12 / 2008-10-17$$gWCEE15
000011891 720__ $$aTodorovska, Maria I.
000011891 8560_ $$ffischerc@itam.cas.cz
000011891 8564_ $$s2041152$$uhttps://invenio.itam.cas.cz/record/11891/files/11-0173.pdf$$yOriginal version of the author's contribution as presented on CD, Paper ID: 11-0173.
000011891 962__ $$r9324
000011891 980__ $$aPAPER