Seismic Analysis for Pile Foundations in the Liquefiable Soil Layer Using FLAC3D

2015 ◽  
Vol 764-765 ◽  
pp. 1114-1118
Author(s):  
Yuan Chieh Wu ◽  
Che Wei Hu
Keyword(s):  
Seismic Response ◽  
Seismic Analysis ◽  
Soil Layer ◽  
Response Prediction ◽  
Practical Method ◽  
Soil Liquefaction ◽  
Nuclear Industry ◽  
Pile Foundations ◽  
Centrifuge Model Test ◽  
Liquefiable Soil

Pile foundation is the practical method to enhance earthquake-resistant ability for structures located in liquefiable soil sites. Soil liquefaction impact has been occurred such as Kashiwazaki-Kariwa NPP in 2007 Chūetsu offshore earthquake because of the soft backfill soil. To understand the behavior of pile foundations in liquefied soil during earthquake attack and conform to nuclear standard, seismic analysis with soil-structure interaction considering liquefaction using the finite difference program FLAC3D is developed to renew the traditional method used in nuclear industry. The models are verified according to a series of centrifuge model test results conducted in National Central University, Taiwan, to show the accuracy of seismic response prediction, and it provides the more advanced tool to demonstrate the detail of seismic response so that the utility and authority can easily decide the disaster prevention strategy.

scholarly journals Criteria for Preliminary Design of an Arched Steel Bridge on Shallow Foundation Under Soil Liquefaction Conditions

2017 ◽  
Vol 11 (1) ◽  
pp. 1170-1190 ◽  
Author(s):  
Isabella Vassilopoulou ◽  
Vasiliki Kaymenaki ◽  
Charis J. Gantes ◽  
George Bouckovalas
Keyword(s):  
Seismic Isolation ◽  
Design Method ◽  
Soil Layer ◽  
Soil Liquefaction ◽  
Shallow Foundation ◽  
Preliminary Design ◽  
Steel Bridge ◽  
Foundation Design ◽  
Deep Foundation ◽  
Liquefiable Soil

Introduction: The research is based on a proposed new foundation design method of bridges on liquefiable soil, consisting of using a shallow foundation and exploiting the liquefiable soil layer as natural seismic isolation, replacing thus the commonly employed deep foundation method. The use of this concept may be hindered by detrimental effects, such as large displacements and rotations that are expected to take place at the foundation of the structure during a strong seismic event, associated with permanent displacements due to the liquefaction phenomenon. Methods: The aim of the current study is to investigate the response of an arched steel bridge with two simply supported spans to displacements and rotations induced by soil liquefaction, delineate the acceptable limits of such ground movements that the bridge can sustain, avoiding the collapse of the superstructure, and define criteria for the preliminary design of the spread footing of the middle pier. To that effect, nonlinear analyses are performed, taking into account geometric and material nonlinearities. Displacements and rotations are imposed at the base of the pier and their amplitude is gradually increased until the first group of structural elements that reach failure is detected. Results and Conclusion: The values of displacements and rotations, for which failure occurs, specify the tolerable design limits. This is a first step towards investigating the feasibility of the above concept for bridges of this type.

The Uplift Behavior of Large Underground Structures in Liquefied Field

2011 ◽  
Vol 90-93 ◽  
pp. 2112-2118 ◽  
Author(s):  
Xi Wen Zhang ◽  
Xiao Wei Tang ◽  
Qi Shao ◽  
Xu Bai
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Geometrical Nonlinearity ◽  
Soil Layer ◽  
Ground Surface ◽  
Soil Liquefaction ◽  
Underground Structures ◽  
Liquefiable Soil ◽  
The Stability ◽  
Updated Lagrangian

Soil liquefaction due to the earthquake causes serious damages and engineering problems, such as the reduction of the soil strength, large settlement of the ground surface, the flow of liquefied soil and the uplift behavior to the underground structures, and the large deformation induced by the uplift force threatens the stability and safety of the structures. In this paper, a FE-FD coupled method is used in the simulation, the cyclic elasto-plastic constitutive model and the updated lagrangian formulation are applied to deal with the material and geometrical nonlinearity of liquefied soil. The results show that after the earthquake, the exceed pore water pressure will still exist for some time and the structure has an obvious vertical uplift displacement related to the liquefied area and the flow of liquefied soil. The uplift displacement will decrease as the thickness of the upper liquefiable soil layer is reduced. The results can be regarded as a guidance and reference for the design of the large underground structures.

scholarly journals Numerical Simulations of the Seismic Response of a RC Structure Resting on Liquefiable Soil

Buildings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 379
Author(s):  
Saif Alzabeebee ◽  
Davide Forcellini
Keyword(s):  
Seismic Response ◽  
Lateral Displacement ◽  
Soil Layer ◽  
Coupled Analysis ◽  
Percentage Increase ◽  
Soil Density ◽  
Predominant Frequency ◽  
Liquefiable Soil ◽  
Rc Structure ◽  
Wide Range

The seismic response of buildings resting on liquefiable soil is a complex problem that is still poorly understood despite numerous studies on the topic. This paper attempts to enhance the understanding of this phenomenon by simulating an RC structure resting on liquefiable soil and subjected to seismic shakes. The solid-fluid fully coupled analysis was conducted with OpenSeesPL utilizing 58 earthquake records to simulate a wide range of shaking scenarios. In addition, the effect of the soil density and the thickness of the liquefiable layer were examined. It was noted that the liquefaction-induced settlement of the building increased as peak ground acceleration (PGA) increased, where the percentage increase ranged between 2.5% and 888.0% depending on the soil density, thickness of the liquefiable layer, PGA and the predominant frequency of the seismic shake. However, a scatter of the relationship between the PGA and the liquefaction-induced settlement was also noted due to the effect of the predominant frequency of the seismic shake. In addition, a reduced effect from soil density on the liquefaction-induced settlement was observed, where the settlement changed by up to 55% as the soil density changed from loose to medium, and by 68% as the density changed from loose to dense. Additionally, the results of the lateral displacement of the building did not show a definite trend with the increase in PGA, which could be attributed to the complex interaction between PGA amplification and the predominant frequency of the seismic shake as the liquefiable soil layer thickness changed.

Seismic response of pile foundations in liquefiable soil: parametric study

2011 ◽  
Vol 5 (6) ◽  
pp. 1307-1315 ◽  
Author(s):  
Asskar Janalizade Choobbasti ◽  
Meysam Saadati ◽  
Hamid Reza Tavakoli
Keyword(s):  
Seismic Response ◽  
Parametric Study ◽  
Pile Foundations ◽  
Liquefiable Soil

Influence of Ground Properties on Seismic Response of Tower Cranes Supported by Pile Foundations

2008 ◽  
Vol 1 (1) ◽  
pp. 37-46
Author(s):  
Satoshi TAMATE ◽  
Yasuo TOYOSAWA ◽  
Seiji TAKANASHI ◽  
Kazuya ITOH ◽  
Naoaki SUEMASA ◽  
...  
Keyword(s):  
Seismic Response ◽  
Pile Foundations

scholarly journals Sustainable Measures for Protection of Structures Against Earthquake Induced Liquefaction

2021 ◽  
Author(s):  
Gopal S. P. Madabhushi ◽  
Samy Garcia-Torres
Keyword(s):  
Soil Liquefaction ◽  
Excess Pore Pressure ◽  
Economic Losses ◽  
Element Analysis ◽  
Centrifuge Testing ◽  
Centrifuge Tests ◽  
Liquefiable Soil ◽  
Recent Earthquakes ◽  
Excess Pore Pressures ◽  
Excess Pore

AbstractSoil liquefaction can cause excessive damage to structures as witnessed in many recent earthquakes. The damage to small/medium-sized buildings can lead to excessive death toll and economic losses due to the sheer number of such buildings. Economic and sustainable methods to mitigate liquefaction damage to such buildings are therefore required. In this paper, the use of rubble brick as a material to construct earthquake drains is proposed. The efficacy of these drains to mitigate liquefaction effects was investigated, for the first time to include the effects of the foundations of a structure by using dynamic centrifuge testing. It will be shown that performance of the foundation in terms of its settlement was improved by the rubble brick drains by directly comparing them to the foundation on unimproved, liquefiable ground. The dynamic response in terms of horizontal accelerations and rotations will be compared. The dynamic centrifuge tests also yielded valuable information with regard to the excess pore pressure variation below the foundations both spatially and temporally. Differences of excess pore pressures between the improved and unimproved ground will be compared. Finally, a simplified 3D finite element analysis will be introduced that will be shown to satisfactorily capture the settlement characteristics of the foundation located on liquefiable soil with earthquake drains.

Centrifuge Modeling on Seismic Behavior of Pile in Liquefiable Soil Ground

2013 ◽  
Vol 479-480 ◽  
pp. 1139-1143
Author(s):  
Wen Yi Hung ◽  
Chung Jung Lee ◽  
Wen Ya Chung ◽  
Chen Hui Tsai ◽  
Ting Chen ◽  
...  
Keyword(s):  
Seismic Behavior ◽  
Soil Structure ◽  
Lateral Displacement ◽  
Bending Moment ◽  
Soil Liquefaction ◽  
Centrifuge Modeling ◽  
Shaking Table ◽  
Pile Head ◽  
Liquefiable Soil ◽  
Tip Mass

Dramatic failure of pile foundations caused by the soil liquefaction was founded leading to many studies for investigating the seismic behavior of pile. The failures were often accompanied with settlement, lateral displacement and tilting of superstructures. Therefore soil-structure interaction effects must be properly considered in the pile design. Two tests by using the centrifuge shaking table were conducted at an acceleration field of 80 g to investigate the seismic response of piles attached with different tip mass and embedded in liquefied or non-liquefied deposits during shaking. It was found that the maximum bending moment of pile occurs at the depth of 4 m and 5 m for dry sand and saturated sand models, respectively. The more tip mass leads to the more lateral displacement of pile head and the more residual bending moment.

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