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Proceedings Paper

Structural system identification of buildings by a wave method based on a layered Timoshenko beam model
Author(s): Mahdi Ebrahimian; Maria I. Todorovska
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Paper Abstract

A layered Timoshenko beam (TB) model of a high-rise building is presented and applied to system identification of a full-scale building from recorded seismic response. This model is a new development in a wave method for earthquake damage detection and structural health monitoring being developed by the authors’ research group. The method is based on monitoring changes in the wave properties of the structure, such as the velocity of wave propagation vertically through the structure. This model is an improvement over the previously used layered shear beam (SB) model because it accounts for wave dispersion caused by flexural deformation present in addition to shear. It also accounts for the rotatory inertia and the variation of the building properties with height. The case study is a 54-story steel frame building located in downtown Los Angeles. Recorded accelerations during the Northridge earthquake of 1994 are used for system identification of the NS response. The model parameters are identified by matching, in the least squares sense, the model and observed impulse response functions at all levels where motion was recorded. The model is then used to compute the building vertical phase and group velocities. Impulse responses computed by deconvolution of the recorded motions with the roof response are used, which represent the building response to a virtual source at the roof. The better match of transfer-function amplitudes of the fitted TB model than of previously fitted SB model indicates that the layered TB model is a better physical model for this building.

Paper Details

Date Published: 9 March 2014
PDF: 13 pages
Proc. SPIE 9064, Health Monitoring of Structural and Biological Systems 2014, 90641C (9 March 2014); doi: 10.1117/12.2045219
Show Author Affiliations
Mahdi Ebrahimian, The Univ. of Southern California (United States)
Maria I. Todorovska, The Univ. of Southern California (United States)

Published in SPIE Proceedings Vol. 9064:
Health Monitoring of Structural and Biological Systems 2014
Tribikram Kundu, Editor(s)

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