engleski

Evaluation of the Site Amplification Factors Estimated by Equivalent Linear Site Response Analysis Using Time Series and Random Vibration Theory Based Approaches

One dimensional (1-D) equivalent-linear (EQL) site response analysis is widely used to estimate the amplification of ground motion intensity measures due to local site conditions. The objective of this study is to estimate and compare the site amplification factors (AFs) using two different 1- D EQL analysis approaches: the time series (TS) approach that employs the recorded ground motions that are suitable with the bedrock design spectrum and the random vibration theory (RVT) based method that utilizes the stochastic spectrum for the design earthquake. Random soil profiles with different soil types, groundwater conditions, and EQL soil properties are combined in the analysis with different ground shaking levels. Analysis results showed that the AFs estimated by the TS- approach are systematically higher than the AFs estimated in RVT-based method in the short period range (T<0.5 s), especially when the bedrock peak ground acceleration (PGA) is higher than 0.2g. The non-linear behaviour of the soil observed in the high input PGA levels prolongs the predominant period of soil profile and this effect is more prominent in the RVT-based analysis. At the predominant period, the AFs calculated by the RVT- based method are approximately 5-25% higher than the AF estimated by TS- approach. The AFs calculated in this study are found to be in good agreement with the empirical AF models utilized in recent ground motion prediction models, indicating that the RVT-based AF models may be preferred in the future to cover a larger range of scenarios than the empirical datasets.

site response ; equivalent-linear analysis ; random vibration theory ; dynamic soil behaviour ; site amplification ; ground motion prediction models

nije evidentirano