Original scientific paper
Response of structures isolated with elastomeric bearings subjected to low-intensity earthquakes
Tatjana Isaković
orcid.org/0000-0002-7712-5931
; Faculty of Civil Engineering, University of Ljubljana, Ljubljana, SLOVENIA
Matej Fischinger
; Faculty of Civil Engineering, University of Ljubljana, Ljubljana, SLOVENIA
Jaka Zevnik
; Faculty of Civil Engineering, University of Ljubljana, Ljubljana, SLOVENIA
Abstract
When deformations of the rubber are small, its stiffness significantly increases. This increase of stiffness shortens the period of the structure and it may shift it into the resonant region in the earthquake acceleration spectrum. Therefore, the seismic isolation with elastomeric bearings may become ineffective. Due to the less effective base isolation the equipment installed in the structures can be particularly jeopardized. To identify when the standard elastomeric bearings become ineffective, a parametric study was performed. The yield force and yield displacement of bearings were varied. In this way the influence of the bearing nonlinearity and damping to the effectiveness of the base isolation was studied. The standard bilinear macro model of the elastomeric bearings could not be used in this parametric study, since it can not describe the response of the bearings in the small deformation range, realistically. Therefore, an enhanced macro model was studied and used in the analysis. Primarily, the floor acceleration spectra were analyzed since it was expected that the equipment, installed in the structures was jeopardized more than the structure itself. It was found that the standard elastomeric bearings were less effective when their response corresponding to the weaker earthquakes was more nonlinear. In these cases the applicability of the new smart semi-active elastomeric bearing, which can keep the stiffness independent of the load intensity was found feasible. This device is also briefly described
Keywords
seismic isolation, numerical models, elastomeric bearings, floor spectra
Hrčak ID:
295247
URI
Publication date:
9.12.2006.
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