System Identification of Buildings with Mid-Story Isolation Considering Torsional Coupling Effect
Date Issued
2012
Date
2012
Author(s)
Chiu, Cheng-Hao
Abstract
This thesis constructs a system identification procedure of building with mid-story isolation, expecting to identify physical parameters of a building with a simplified modal. We use lump mass method, simplifying a building with mid-story isolation into a three lump mass system. These are superstructure, floor above isolation system, substructure. For the superstructure, we calculate effective modal mass to simplify multiple degrees of freedom system, and we consider it has torsional coupling effect in superstructure. We consider there are three degrees of freedom (Longitudinal, Transverse and Torsional) in every lump mass .There are nine degrees of freedom in the system. Linear mechanical behavior is assumed in superstructure and substructure; bilinear mechanical behavior is assumed in isolation story.
We used the concept of least square method in the identification. This is a nonlinear least square problem because there are two eccentricities in superstructure. We used Levenberg-Marquardt algorithm to solve nonlinear least square problem, and used Masing criteria to describe the mechanical behavior of LRB.
In numerical example, we estimated the structural parameter to construct a nine degrees of freedom idealized mid-story isolation building. We input El Centro earthquake and calculated dynamics response of all degrees of freedom by Newmark linear acceleration method. We used the response to identify the structural parameters. By numerical example , we hope to improve accurate of the modal and the reasonable of the procedure.
Finally, the reliability of present procedure was verifien by calculating the error index between the measure data and identified results from new Civil Buildind at NTU.
Subjects
System Identification
Building of Mid-Story Isolation
Levenberg-Marquardt Algorithm
Torsional Coupling Effect
Least Square Method
Type
thesis
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