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An investigation of soil-structure interaction effects observed at the MIT Green Building

January 1, 2016

The soil-foundation impedance function of the MIT Green Building is identified from its response signals recorded during an earthquake. Estimation of foundation impedance functions from seismic response signals is a challenging task, because: (1) the foundation input motions (FIMs) are not directly measurable, (2) the as-built properties of the super-structure are only approximately known, and (3) the soil-foundation impedance functions are inherently frequency-dependent. In the present study, aforementioned difficulties are circumvented by using, in succession, a blind modal identification (BMID) method, a simplified Timoshenko beam model (TBM), and a parametric updating of transfer functions (TFs). First, the flexible-base modal properties of the building are identified from response signals using the BMID method. Then, a flexible-base TBM is updated using the identified modal data. Finally, the frequency-dependent soil-foundation impedance function is estimated by minimizing the discrepancy between TFs (of pairs instrumented floors) that are (1) obtained experimentally from earthquake data and (2) analytically from the updated TBM. Using the fully identified flexible-base TBM, the FIMs as well as building responses at locations without instruments can be predicted, as demonstrated in the present study.

Publication Year 2016
Title An investigation of soil-structure interaction effects observed at the MIT Green Building
DOI 10.1193/072215EQS118M
Authors Ertugrul Taciroglu, Mehmet Çelebi, S. Farid Ghahari, Fariba Abazarsa
Publication Type Article
Publication Subtype Journal Article
Series Title Earthquake Spectra
Index ID 70189626
Record Source USGS Publications Warehouse
USGS Organization Earthquake Science Center