• RAMENDU BIKAS SAHU

      Articles written in Journal of Earth System Science

    • Influence of trapped soft/stiff soil layer in seismic site response analysis

      NARAYAN ROY SIBAPRIYA MUKHERJEE RAMENDU BIKAS SAHU

      More Details Abstract Fulltext PDF

      As the ground response analysis serves an integral part of site specific seismic hazard study to obtain design ground motion, a proper and accurate estimation should be of prime importance. The paper presents a study on the effect of trapped soft and stiff soil layer on equivalent linear ground response analysis implemented in computer program STRATA. For this purpose, the concept of normally stiff and inversely stiff soil profiles have been introduced. The study clearly indicates the higher impact of a trapped soft soil layer profile, i.e., inversely stiff soil profile with soft layer, in comparison with trapped stiff layer profile, i.e., inversely stiff profile with stiff layer. For low to moderate ground motions, as the depth of the trapped soft layer increases, peak amplification and peak frequency reduces, and for high intensity input ground motion, significant reduction only in the peak frequencies is observed. On the other hand, as the depth of trapped stiff soil layer increases the outcome of ground response analysis remain quite similar. Peak transfer function, peak frequency, peak spectral ratio and peak spectral acceleration are found to exhibit a COV $\leq$ 60 to 100% for all combinations of IS-Soft profiles, whereas, IS-Stiff profiles exhibit a maximum COV $\leq$ 15 to 25% for all the considered input ground motions. Computed normalized-root mean square error (Norm-RMSE) values also clearly indicate the higher deviations in the ground response analysis for different combinations of trapped soft soil profiles, from that of normally stiff profile, whereas, trapped stiff layer profiles show lower deviations in the Norm-RMSE values. The profiles with trapped soft layer exhibit a Norm-RMSE value  $\leq$ 0.8, whereas, trapped stiff layer profiles exhibit a Norm-RMSE value  $\leq$ 0.2, which clearly demonstrate the large deviations in the outcome of ground response analysis in case of trapped soft layer profiles.

  • Journal of Earth System Science | News

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2021-2022 Indian Academy of Sciences, Bengaluru.