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1. Sensitivity analysis of LEAP soil liquefaction tests

   Zeghal, M.; Goswami, N.; Manzari, M.T.; Kutter, B.L. (July 2019, Earthquake Geotechnical Engineering for Protection and Development of Environment and Constructions)

   An analysis is conducted to assess the sensitivity of 17 replicas of a saturated sloping deposit tests conducted within the 2017 Liquefaction Experiments and Analysis Projects (LEAP). A difference analysis is first used to quantify the dissimilarities between recorded input acceleration time histories. This analysis provided a unique decomposition of the differences in terms of phase, frequency-shift, amplitude at 1 Hz, and amplitude of frequency components higher than 2 Hz (2+Hz). A kriging analysis was used to evaluate the sensitivity of the deposit response accelerations to differences in input motion amplitude at 1Hz and 2+Hz and cone penetration resistance. The analysis showed a response that is more sensitive to variations in cone penetration resistance values than to amplitude of the input 1Hz and 2+Hz motion (frequency) components. 

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2. Sensitivity analysis of LEAP soil liquefaction tests

   Zeghal, M. (June 2019, Proceedings of 7th International Conference on Earthquake Geotechnical Engineering)

   An analysis is conducted to assess the sensitivity of 17 replicas of a saturated sloping deposit tests conducted within the 2017 Liquefaction Experiments and Analysis Projects (LEAP). A difference analysis is first used to quantify the dissimilarities between recorded input acceleration time histories. This analysis provided a unique decomposition of the differences in terms of phase, frequency-shift, amplitude at 1 Hz, and amplitude of frequency components higher than 2 Hz (2+Hz). A kriging analysis was used to evaluate the sensitivity of the deposit response accelerations to differences in input motion amplitude at 1Hz and 2+Hz and cone penetration resistance. The analysis showed a response that is more sensitive to variations in cone penetration resistance values than to amplitude of the input 1Hz and 2+Hz motion (frequency) components. 

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3. Difference and Sensitivity Analyses of the LEAP-2017 Experiments

   https://doi.org/10.1007/978-3-030-22818-7_7  

   Goswami, N. (November 2019, Proceedings of LEAP_UCD-2017 workshop)

   The experimental results of LEAP (Liquefaction Experiments and Analysis Projects) centrifuge test replicas of a saturated sloping deposit are used to assess the sensitivity of soil accelerations to variability in input motion and soil deposition. A difference metric is used to quantify the dissimilarities between recorded acceleration time histories. This metric is uniquely decomposed in terms of four difference component measures associated with phase, frequency shift, amplitude at 1 Hz, and amplitude of frequency components higher than 2 Hz (2 + Hz). The sensitivity of the deposit response accelerations to differences in input motion amplitude at 1 Hz and 2 + Hz and cone penetration resistance (used as a measure reflecting soil deposition and initial grain packing condition) was obtained using a Gaussian process-based kriging. These accelerations were found to be more sensitive to variations in cone penetration resistance values than to the amplitude of the input motion 1 Hz and 2 + Hz (frequency) components. The sensitivity functions associated with this resistance parameter were found to be substantially nonlinear. 

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4. Discrepancy Metrics and Sensitivity Analysis of Dynamic Soil Response

   https://doi.org/10.1061/9780784481479.012  

   Zeghal, Mourad; Goswami, Nithyagopal; Manzari, Majid; Kutter, Bruce (June 2018, Geotechnical Earthquake Engineering and Soil Dynamics V)

   The mean squared deviation between acceleration time histories (of soil-system test replicas) is expressed as a unique aggregate of three discrepancy measures associated with shape, phase, and frequency-shift. The shape-measure quantifies the deviations associated with dissimilarities in form and amplitude. The phase-measure estimates the deviations associated with differences in phase angle. The frequency-shift-measure quantifies the deviations associated with differences in frequency components. These measures were used to assess the discrepancies among six replicas of a centrifuge experiment of a liquefiable soil tested at six different facilities. A sensitivity analysis was thereafter used to assess the effects of input motion discrepancies on a liquefiable soil response. The conducted analysis showed that the acceleration response of the analyzed soil is more sensitive to discrepancies in input motion frequency than in phase or amplitude. 

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5. Metrics for the Comparison of Acceleration Time Histories

   https://doi.org/10.1061/9780784480489.022  

   Goswami, Nithyagopal; Zeghal, Mourad; Manzari, Majid; Kutter, Bruce (January 2017, Geoteh)

   A decomposition is used to express the mean squared deviation, quantifying the dissimilarities between time histories of input (or response) quantities of multiple replicas of a soil system centrifuge test, as a unique aggregate of three discrepancy measures associated with shape, phase and frequency-shift. The shape measure quantifies the deviations associated with dissimilarities in form and amplitude. The phase measure estimates the deviations associated with differences in phase angle. The frequency-shift measure quantifies the deviations associated with differences in frequency components. These measures are illustrated using simple synthetic motions and used to assess the discrepancies among six replicas of centrifuge input motion achieved at six different facilities. The conducted analysis shows that the proposed decomposition accurately quantifies the different types of discrepancies in input or response time histories. 

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