Enhancing Structural Seismic Response Insight of RC Frame by Time-Frequency Decomposition
Date Issued
2011
Date
2011
Author(s)
Li, Jung-Huan
Abstract
Reinforced concrete structures typically exhibit nonlinear and inelastic behavior under severe dynamic loading, such as under earthquakes. Earthquake engineering considers both the expected performance of structures in an earthquake and the state of the damage after seismic events. According to the literature review, it is clear that using complex non-linear model to simulate the nonlinear behavior of the RC structures, such as the Bouc-Wen model, may need to identify many unknown model parameters. To reduce the number of unknow parameters in modeling the nonlinear and inelastic behavior of the seismic response of reinfoorced concrete, the Deteriorating Distributed Element model was used in this study to simulate the seismic response of the RC structures.
The objective of this research is to apply the Deteriorating Distributed Element model to simulate the nonlinear response of reinforced concrete structures. An advanced signal processing technique is used to investigate the physical parameters of a inelastic system in the degrading hysteretic model of a reinforced concrete frame. First, the Singular Spectrum Analysis was used to extract the steady-state signals from the nonlinear RC signal; and then the Nonlinear Singular Spectrum Analysis method was adapt to analyze the non-stationary signal of seismic response of RC frame so as to extract a stable single-frequency signals. Through the singular spectrum analysis (SSA) and the nonlinear SSA, the original seismic response data is decomposed into independent additive components of decreasing weight which can be used for developing hysteresis loop also in degrading order. Finally, the Deteriorating Distributed Element (DDE) model is applied to simulate the damage pattern of the reinforced concrete frame with respect to each of the developed degrading hysteresis loop and to identify the degrading stiffness and equivalent damping ratio. Comparison between the developed DDE model with the recorded physical indices and the results of structural system identification is also discussed.
Finally, the Recursive Stochastic Subspace Identification method was applied, to verify the nonlinear response of the RC structural reliability through the simulation of using the DDE model.
Subjects
Deteriorating Distributed Element model
Singular Spectrum Analysis
Nonlinear Singular Spectrum Analysis
signal processing
the degrading stiffness
equivalent damping ratio
Recursive Stochastic Subspace Identification
Type
thesis
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