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1. EXPERIMENTAL P-Y CURVES FROM CENTRIFUGE TESTS ON PILE FOUNDATIONS SUBJECTED TO LIQUEFACTION AND LATERAL SPREADING

   Souri, Milad ; Khosravifar, Arash ; Schlechter, Scott ; McCullough, Nason ; Dickenson, Steve ( January 2019 , 2019 44th Annual Conference on Deep Foundations)

   null (Ed.)

   The results of five centrifuge models were used to evaluate the response of pile-supported wharves subjected to inertial and liquefaction-induced lateral spreading loads. The centrifuge models contained pile groups that were embedded in rockfill dikes over layers of loose to dense sand and were shaken by a series of ground motions. The p-y curves were back-calculated for both dynamic and static loading from centrifuge data and were compared against commonly used API p-y relationships. It was found that a significant reduction in ultimate soil resistance occurred in dynamic p-y curves in partially/fully liquefied soils as compared to static p-y curves. It was also found that incorporating p-multipliers that are proportional to the pore water pressure ratio in granular materials is adequate for estimating pile demands in pseudo static analysis. 

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2. Seismic Performance of Pile-Supported Piers and Wharves Subjected to Foundation Deformations

   https://doi.org/10.1061/9780784482612.058  

   Souri, Milad ; Khosravifar, Arash ; Dickenson, Stephen ; Schlechter, Scott ; McCullough, Nason ( September 2019 , Ports 2019)

   The interaction of inertial and kinematic demands is investigated using data from five physical models of pile-supported wharves using a large-scale geotechnical centrifuge. The wharf structures in this study were subjected to a suite of recorded ground motions, therefore associated superstructure inertia, and earthquake-induced slope deformations of varying magnitudes. The observations from these tests were used to provide insights on how to estimate large bending moments that developed at pile head and at depths significantly below a commonly assumed point of fixity that are associated with deep-seated ground deformations. Design recommendations are proposed on how to combine inertial and kinematic demands in a manner that is representative of the global structure. 

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3. Effect of soil-structure interaction on sand deposits supported by a sheet-pile wall under liquefied conditions

   Korre, Evangelia ; Abdoun, Tarek ; Zeghal, Mourad ( September 2022 , 10th International Conference on Physical Modelling in Geotechnics)

   Moonkyung Chung, Sung-Ryul Kim (Ed.)

   Retaining structures in waterfront areas are sensitive to seismically triggered liquefaction, leading to large deformations of the backfill and the retaining structure. The response of such systems depends heavily on the soil parameters, one of the most important being its relative density. This paper summarizes the key aspects of three centrifuge experiments performed at the Center for Earthquake Engineering Simulation (CEES) at Rensselaer Polytechnic Institute in 2020 as part of the experimental campaign for the Liquefaction Experiments and Analysis Project (LEAP-2020). The three models reflected the same prototype problem of a rigid floating sheet-pile quay wall supporting a 3-m-deep liquefiable soil deposit, of loose, medium dense and dense soil relative densities. The three models observed the same building technique and were subjected to the same target dynamic input motion. 

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4. LEAP-UCD-2017 Centrifuge Test at University of California, Davis

   https://doi.org/10.1007/978-3-030-22818-7_13  

   Carey, Trevor J. ; Stone, Nicholas ; Bonab, Masoud H. ; Kutter, Bruce L. ( January 2020 , Model Tests and Numerical Simulations of Liquefaction and Lateral Spreading)

   Three centrifuge experiments were performed at the University of California, Davis, for LEAP-UCD-2017. LEAP is a collaborative effort to assess repeatability of centrifuge test results and to provide data for the validation of numerical models used to predict the effects of liquefaction. The model configuration used the same geometry as the LEAP-GWU-2015 exercise: a submerged slope of Ottawa F-65 sand inclined at 5 degrees in a rigid container. This paper focuses on presenting results from the two destructive ground motions from each of the three centrifuge models. The effect of each destructive ground motion is evaluated by accelerometer recordings, pore pressure response, and lateral deformation of the soil surface. New techniques were implemented for measuring liquefaction-induced lateral deformations using five GoPro cameras and GEO-PIV software. The methods for measuring the achieved density of the as-built model are also discussed. 

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5. Repeatability Potential and Challenges in Centrifuge Physical Modeling in the Presence of Soil-Structure Interaction for LEAP-2020.

   https://doi.org/10.1007/978-3-031-11898-2_162  

   Korre, Evangelia ; Abdoun, Tarek ; Zeghal, Mourad ( July 2022 , Conference on Performance-based Design in Earthquake Geotechnical Engineering (PBD-iv2022))

   The LEAP (Liquefaction Experiment and Analysis Project) is a continuing international collaboration to create a reliable databank of high-quality experimental results for the validation of numerical tools. This paper investigates the response of a floating rigid sheet-pile quay wall under conditions of seismically induced liquefaction, embedded in dense sand and supporting a saturated liquefiable soil deposit. The experimental challenges related to repeatability in physical modeling in such a soil-structure-interaction regime are also discussed. To this end, three experiments performed at Rensselaer Polytechnic Institute (RPI) as part of the experimental campaign for the LEAP-2020 are discussed herein. Models RPI_REP-2020 and RPI10-2020 investigate the repeatability potential in centrifuge modeling in the presence of soil-structure-interaction. Model RPI_P-2020 is the pilot test of the LEAP-2020 experimental campaign at RPI and investigates the effect of the wall’s initial orientation on the system’s dynamic response and soil liquefaction, as a possible “defect” in the model construction procedure. The three models were built in a consistent way, employed comparable instrumentation layout while simulating the same prototype and comparable soil conditions. The three models were subjected to the same acceleration target input motion, which was repeated across all three models with high consistency. 

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