Kinematic and inertial effects on piled rafts in soft ground supporting isolated and non-isolated buildings observed during the 2011 Tohoku earthquake

Based on previous studies on the seismic monitoring of isolated (IS) and non-isolated (NI) buildings supported by piled rafts with a DMW (deep mixing wall) grid, under similar soft-soil conditions during the 2011 Tohoku earthquake, the effects of kinematic and inertial forces on the piled rafts, for...

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Main Authors: Kiyoshi Yamashita, Junji Hamada
Format: Article
Language:English
Published: Elsevier 2023-10-01
Series:Soils and Foundations
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S0038080623001014
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author Kiyoshi Yamashita
Junji Hamada
author_facet Kiyoshi Yamashita
Junji Hamada
author_sort Kiyoshi Yamashita
collection DOAJ
description Based on previous studies on the seismic monitoring of isolated (IS) and non-isolated (NI) buildings supported by piled rafts with a DMW (deep mixing wall) grid, under similar soft-soil conditions during the 2011 Tohoku earthquake, the effects of kinematic and inertial forces on the piled rafts, for which the natural periods of the superstructures were significantly different, were investigated. To evaluate the degree of contribution of the kinematic and inertial forces on the maximum bending moments and incremental axial forces near the pile heads, the coefficients related to the kinematic and inertial forces were presented. The coefficients of inertial force were separated into those of the superstructure and raft inertias to consider the embedment effects. Furthermore, the mechanisms of the inelastic behavior of the settlement and the load transfer in the piled raft systems, observed during the principal motion, were discussed. Consequently, it was found that the ratio of the natural period of the soil-pile-structure system to the predominant period of the ground, Ts/Tg, plays an important role in the contribution of the kinematic and inertial forces to the maximum bending moments near the pile head. Moreover, the Ts/Tg values were seen to be closely related to the differences in the inelastic settlement and load transfer mechanisms of the piled raft systems.
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spelling doaj.art-ce854a2eca2d430b8774ff4d633eb2bb2023-11-04T04:17:08ZengElsevierSoils and Foundations2524-17882023-10-01635101372Kinematic and inertial effects on piled rafts in soft ground supporting isolated and non-isolated buildings observed during the 2011 Tohoku earthquakeKiyoshi Yamashita0Junji Hamada1Corresponding author.; Takenaka Research and Development Institute, Takenaka Corporation, Chiba, JapanTakenaka Research and Development Institute, Takenaka Corporation, Chiba, JapanBased on previous studies on the seismic monitoring of isolated (IS) and non-isolated (NI) buildings supported by piled rafts with a DMW (deep mixing wall) grid, under similar soft-soil conditions during the 2011 Tohoku earthquake, the effects of kinematic and inertial forces on the piled rafts, for which the natural periods of the superstructures were significantly different, were investigated. To evaluate the degree of contribution of the kinematic and inertial forces on the maximum bending moments and incremental axial forces near the pile heads, the coefficients related to the kinematic and inertial forces were presented. The coefficients of inertial force were separated into those of the superstructure and raft inertias to consider the embedment effects. Furthermore, the mechanisms of the inelastic behavior of the settlement and the load transfer in the piled raft systems, observed during the principal motion, were discussed. Consequently, it was found that the ratio of the natural period of the soil-pile-structure system to the predominant period of the ground, Ts/Tg, plays an important role in the contribution of the kinematic and inertial forces to the maximum bending moments near the pile head. Moreover, the Ts/Tg values were seen to be closely related to the differences in the inelastic settlement and load transfer mechanisms of the piled raft systems.http://www.sciencedirect.com/science/article/pii/S0038080623001014Base isolationBuildingDeep mixing wallPiled raft foundationPile stressSeismic observation
spellingShingle Kiyoshi Yamashita
Junji Hamada
Kinematic and inertial effects on piled rafts in soft ground supporting isolated and non-isolated buildings observed during the 2011 Tohoku earthquake
Soils and Foundations
Base isolation
Building
Deep mixing wall
Piled raft foundation
Pile stress
Seismic observation
title Kinematic and inertial effects on piled rafts in soft ground supporting isolated and non-isolated buildings observed during the 2011 Tohoku earthquake
title_full Kinematic and inertial effects on piled rafts in soft ground supporting isolated and non-isolated buildings observed during the 2011 Tohoku earthquake
title_fullStr Kinematic and inertial effects on piled rafts in soft ground supporting isolated and non-isolated buildings observed during the 2011 Tohoku earthquake
title_full_unstemmed Kinematic and inertial effects on piled rafts in soft ground supporting isolated and non-isolated buildings observed during the 2011 Tohoku earthquake
title_short Kinematic and inertial effects on piled rafts in soft ground supporting isolated and non-isolated buildings observed during the 2011 Tohoku earthquake
title_sort kinematic and inertial effects on piled rafts in soft ground supporting isolated and non isolated buildings observed during the 2011 tohoku earthquake
topic Base isolation
Building
Deep mixing wall
Piled raft foundation
Pile stress
Seismic observation
url http://www.sciencedirect.com/science/article/pii/S0038080623001014
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AT junjihamada kinematicandinertialeffectsonpiledraftsinsoftgroundsupportingisolatedandnonisolatedbuildingsobservedduringthe2011tohokuearthquake