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A shake table investigation of dynamic behavior of pile supported bridges in liquefiable soil deposits

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Earthquake Engineering and Engineering Vibration 2021年第1期20卷 1-24页

作者： Piyush Mohanty Xu Dan Suryakant Biswal subhamoy bhattacharya CSIR-Central Building Research Institute Roorkee247667India Fluor Ltd. 140 Pinehurst RoadFarnboroughGU147BFUK Institute of Engineering Mechanics China Earthquake AdministrationSanhe 065201China University of Surrey GuildfordGU27XHUK

Bridges are a part of vital infrastructure,which should operate even after a disaster to keep emergency services *** have been numerous bridge failures during major past earthquakes due to *** other categories of failures,mid span collapse(without the failure of abutments)of pile supported bridges founded in liquefiable deposits are still observed even in most recent *** mechanism of collapse is attributed to the effects related to the differential elongation of natural period of the individual piers during liquefaction.A shake table investigation has been carried out in this study to verify mechanisms behind midspan collapse of pile supported bridges in liquefiable *** this investigation,a typical pile supported bridge is scaled down,and its foundations pass through the liquefiable loose sandy soil and rest in a dense gravel *** noise motions of increasing acceleration magnitude have been applied to initiate progressive liquefaction and to characterize the dynamic features of the *** has been found that as the liquefaction of the soil sets in,the natural frequency of individual bridge support is reduced,with the highest reduction occurring near the central *** a result,there is differential lateral displacement and bending moment demand on the *** has also been observed that for the central pile,the maximum bending moment in the pile will occur at a higher elevation,as compared to that of the interface of soils of varied stiffness,unlike the abutment *** practical implications of this research are also highlighted.

关键词： bridges midspan failure liquefaction bridge collapse earthquake pile shake table test natural frequency

Assessment of natural frequency of installed offshore wind turbines using nonlinear finite element model considering soil-monopile interaction

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Journal of Rock Mechanics and Geotechnical Engineering 2018年第2期10卷 333-346页

作者： Djillali Amar Bouzid subhamoy bhattacharya Lalahoum Otsmane Department of Civil Engineering Faculty of Technology University Saad Dahled of Blida Department of Civil and Environmental Engineering Tomas Telford Building University of Surrey Department of Material Engineering Faculty of Sciences and TechnologyUniversity of Médéa

A nonlinear finite element model is developed to examine the lateral behaviors of monopiles, which support offshore wind turbines(OWTs) chosen from five different offshore wind farms in Europe. The simulation is using this model to accurately estimate the natural frequency of these slender structures, as a function of the interaction of the foundations with the subsoil. After a brief introduction to the wind power energy as a reliable alternative in comparison to fossil fuel, the paper focuses on concept of natural frequency as a primary indicator in designing the foundations of OWTs. Then the range of natural frequencies is provided for a safe design purpose. Next, an analytical expression of an OWT natural frequency is presented as a function of soil-monopile interaction through monopile head springs characterized by lateral stiffness KL, rotational stiffness KRand cross-coupling stiffness KLRof which the differences are discussed. The nonlinear pseudo three-dimensional finite element vertical slices model has been used to analyze the lateral behaviors of monopiles supporting the OWTs of different wind farm sites considered. Through the monopiles head movements(displacements and rotations), the values of KL, KRand KLRwere obtained and substituted in the analytical expression of natural frequency for comparison. The comparison results between computed and measured natural frequencies showed an excellent agreement for most cases. This confirms the convenience of the finite element model used for the accurate estimation of the monopile head stiffness.

关键词： Nonlinear finite element analysis Vertical slices model Monopiles under horizontal loading Natural frequency Monopile head stiffness Offshore wind turbines(OWTs)

2011年日本东北地区太平洋近海地震地基液化灾害综述

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岩土工程学报 2013年第5期35卷 834-840页

作者：黄雨于淼 bhattacharya subhamoy 同济大学岩土及地下工程教育部重点实验室上海200092 同济大学地下建筑与工程系上海200092 布里斯托尔大学土木工程系萨里大学土木与环境工程系

2011年3月11日,日本太平洋东海岸发生Mw9.0级大地震,并引发巨大海啸,导致了日本东北和关东地区大面积的地基液化震害。通过现场震害调查和最新资料分析,首先较为系统地介绍了日本地震受灾区的液化宏观现象和典型震害特征。其次,研究了... 详细信息

2011年3月11日,日本太平洋东海岸发生Mw9.0级大地震,并引发巨大海啸,导致了日本东北和关东地区大面积的地基液化震害。通过现场震害调查和最新资料分析,首先较为系统地介绍了日本地震受灾区的液化宏观现象和典型震害特征。其次,研究了余震再液化和地震-海啸耦合灾害的破坏机制和特征,指出余震再液化受地震力大小、应力历史及超孔隙水压力消散程度的影响,并将地震和海啸耦合破坏过程分为3个阶段:震后液化阶段、间歇期恢复阶段、海啸流滑破坏阶段;最后,对此次强震中有关抗液化地基处理方法的有效性进行了分析与探讨,以期为今后的地基抗液化设计提供参考与借鉴。

关键词：地震液化再液化地震海啸地基处理