The Impact of Isolation Parameters on Structural Responses due to Strong Earthquake Motion Processed by DWT

Abstract

The parameters of the base isolation system play a significant role in structural responses as they directly affect the interaction between the structure and seismic excitation. This study focuses on investigating the impact of base isolation parameters on structural behavior under decomposed earthquake effects. The period and damping ratio of the isolator, which are inherently effective in determining characteristics such as stiffness and damping coefficients, were parametrically varied to discern their effects on the seismic behavior of the structure. Displacement of the base mat on the isolators and roof acceleration responses were obtained through time response analyses. To examine seismic input across different frequency ranges, discrete wavelet transformation was used to decompose the earthquake acceleration. A five-level decomposition was applied. Subsequently, time response analyses were conducted for the original earthquake acceleration scenario and the corresponding approximation coefficients. Decomposition levels yielding responses similar to those obtained under the original earthquake were identified. Additionally, the correlation between acceleration responses and the earthquake and approximation coefficients was calculated to figure out the effect of the frequency ranges of seismic excitation on the seismic behavior of the building. The adequate decomposition levels for the base-isolated structure have been presented. This analysis illustrates how various frequency ranges of seismic excitation impact the structural response by highlighting which decomposition levels are most representative of the original earthquake effects.

Keywords

• base isolation
• discrete wavelet transform
• earthquake
• time response analysis

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