Analysis of Raft Foundation with EPS Geofoam for Earthquake Resistant

2014 ◽  
Vol 695 ◽  
pp. 613-616
Author(s):  
Mohd Faiz Mohammad Zaki ◽  
Mohammad Fadzli Ramli ◽  
Afizah Ayob ◽  
Mohd Taftazani Ahmad
Keyword(s):  
Structural Engineering ◽  
Soft Soil ◽  
Simulation Models ◽  
Soil Mass ◽  
Dynamic Force ◽  
Finite Element Program ◽  
Eps Geofoam ◽  
Raft Foundation ◽  
Element Program ◽  
Innovative Material

It is becoming a great challenge for civil engineers to design a foundation which able to minimize the effect of an earthquake. A major earthquake produces a strong ground motion in the subsoil and surface structures supported on the soil mass will be induced to move and absorb the dynamic forces. Seismic retrofit of existing foundations is an alternative. However, the modification of this existing foundation toward earthquake resistances raises issues which are far from being totally resolved. Innovative material such as EPS is widely accepted in structural engineering due to its characteristic to absorb the dynamic force effectively. This EPS material demonstrated the practicality and has been applied for geotechnical engineering for various reasons. Based on this, a research which is related to the application of EPS in mitigating the earthquake forces, particularly for raft foundations was conducted properly in this research. The various types and thickness of EPS located beneath the raft foundation and over the soft soil are studied. A finite element program is utilized to develop the computer simulation models. Based on the results, Expended Polystyrene (EPS) Geofoam, placed beneath the raft foundation is able to produces the minimum settlements when subjected to earthquake loading rather than raft foundation modeled without EPS and increasing the density of EPS will simultaneously decrease the settlement of a foundation.

scholarly journals Finite Element Analysis of Structural Engineering Problems Using a Viscoplastic Model Incorporating Two Back Stresses

1995 ◽  
Vol 117 (2) ◽  
pp. 377-383 ◽  
Author(s):  
V. K. Arya ◽  
G. R. Halford
Keyword(s):  
Finite Element ◽  
Structural Engineering ◽  
Nonlinear Finite Element ◽  
Finite Element Analyses ◽  
Element Analysis ◽  
Finite Element Program ◽  
Viscoplastic Model ◽  
Engineering Problems ◽  
Element Program ◽  
Viscoplastic Models

The feasibility of a viscoplastic model incorporating two back stresses and a drag strength is investigated for performing nonlinear finite element analyses of structural engineering problems. The model has recently been put forth by Freed and Walker. The feasibility of the viscoplastic model is demonstrated for nonlinear structural analyses by implementing the model into a finite element program and performing nonlinear finite element analyses for several uniaxial and multiaxial problems. Good agreement is shown to exist between the results obtained using the finite element implementation and those obtained experimentally. The advantages of using advanced viscoplastic models for performing nonlinear finite element analyses of structural components are indicated.

Numerical Analysis of Free Field under Horizontal Seismic Excitations

2012 ◽  
Vol 166-169 ◽  
pp. 2005-2008
Author(s):  
Shou Long Chen ◽  
Chun Yi Cui ◽  
Zhong Tao Wang
Keyword(s):  
Seismic Waves ◽  
Soil Depth ◽  
Soft Soil ◽  
Free Field ◽  
Low Frequency ◽  
Seismic Excitations ◽  
Finite Element Program ◽  
Element Program ◽  
Frequency Components ◽  
Free Bank

Based on Newmark-β gradual integration method and elastic-plastic mechanical theory, numerical analyses of the effects of soft soil depth and thickness on the characteristics of seismic response of free bank field with soft soil layers are conducted by using finite element program Midas/GTS. The numerical results show that the high frequency components of seismic excitations can be filtered and the low frequency components are amplified correspondingly when seismic waves are transmitted through the free bank field from the bedrock.

A Flexure-Shear Coupling Fiber-Section Model for the Cyclic Behavior of R/C Rectangular Hollow Section Bridge Piers

2011 ◽  
Vol 374-377 ◽  
pp. 2009-2012
Author(s):  
Ning Li ◽  
Zhong Xian Li ◽  
Li Li Xie
Keyword(s):  
Nonlinear Behavior ◽  
Simulation Models ◽  
Constitutive Relationship ◽  
Bridge Piers ◽  
Cyclic Behavior ◽  
Thin Wall ◽  
Finite Element Program ◽  
Hollow Section ◽  
Element Program ◽  
Shear Coupling

Reinforced concrete (R/C) bridge pier with hollow section may undergo strongly nonlinear responses when subjecting severe earthquakes. The pier may perform flexure-shear coupling behavior, especially for the thin wall of the hollow section. Some simulation models accounting flexure-axial coupled effects were proposed, however, few simulation model is proposed for R/C hollow section bridge piers mainly impacted by the flexure-shear coupling. In this paper a beam-column element accounting for flexure-shear effect is presented. The mathematical theory for this element is flexibility-based formulation, and the section constructed by fibers can be treated as any kind of bi-axial materials. The cyclic soften membrane model (CSMM) constitutive relationship for plane bi-axial R/C components is used in the determination of the nonlinear behavior. Two cyclic pushover experiments were carried on scaled hollow section piers. The results deduced from the numerical model is compared with the experiment result. This fiber-based model provides sufficient accuracy and computational efficiency. The model has been implemented into the finite element program, OpenSees. And further researches will focus on the flexure-shear induced damage and collapse for bridge structures.

scholarly journals Numerical Analysis of Earthquake Load Mitigation on Rigid Retaining Walls Using EPS Geofoam

2012 ◽  
Vol 6 (1) ◽  
pp. 21-25 ◽  
Author(s):  
Deling Wang ◽  
Richard J. Bathurst
Keyword(s):  
Numerical Simulations ◽  
Retaining Wall ◽  
Expanded Polystyrene ◽  
Numerical Results ◽  
Shaking Table ◽  
Great Promise ◽  
Finite Element Program ◽  
Physical Test ◽  
Eps Geofoam ◽  
Element Program

The mitigation of seismic-induced dynamic earth forces by placing a vertical layer of expanded polystyrene (EPS) geofoam buffer between a rigid retaining wall and the backfill soil is a recent geotechnical innovation. In this paper, the influence of an EPS geofoam buffer on the reduction of dynamic wall forces is numerically studied by simulating the results of three reduced-scale models of rigid walls mounted on a large shaking table. Numerical simulations were carried out using the finite element program ABAQUS. The paper shows that the numerical results capture the trend in earth forces with increasing base acceleration for all three models. The quantitative dynamic load-time response from the numerical simulations was also judged to be in good agreement with measured physical test values. The numerical trend of EPS geofoam also is the same as that of measured test data. With the increasing time, the compression of EPS geofoam increases. And softer EPS geofoam produces more compression which takes more vibration energy by its deformation. The numerical results confirm the results of physical tests that demonstrate that EPS geofoam seismic buffers hold great promise to reduce earthquake-induced dynamic loads against rigid retaining wall structures.

Finite element simulation of seismically induced retrogressive failure of submarine slopes

2005 ◽  
Vol 42 (6) ◽  
pp. 1532-1547 ◽  
Author(s):  
A Azizian ◽  
R Popescu
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Soil Mass ◽  
Finite Element Program ◽  
Seismic Liquefaction ◽  
Element Simulation ◽  
Element Program ◽  
Triggering Mechanisms ◽  
Element Removal ◽  
Silt Layer

Retrogressive failures have been reported for both offshore and onshore slopes subjected to various triggering mechanisms. As a result of large spatial extension of the failure, the retrogression phenomenon leads to significantly increasing damage and may affect facilities located far away from the original slope. The mechanisms of such failures are not fully understood, and reports of analyses are rather scarce. To simulate earthquake-induced retrogressive submarine slope failures and to better understand the mechanisms involved, the element removal capabilities of a finite element program are used to model a soil mass that fails and then flows away, causing upper parts of the slope to fail retrogressively, as a result of the loss of support. It is explained how an initial failure leads to subsequent failures of a flat seafloor. Effects of a shallow silt layer and of a gently sloping seafloor on the extension of retrogression in a sandy seabed are also studied. It is found that the extension of failure increases significantly because of a gentle seafloor slope and (or) the presence of a silt layer.Key words: retrogressive submarine failure, seismic liquefaction, finite elements.

The Soft Soil Foundation Consolidation Numerical Simulation Based on the Model of Modified Cam-Clay

2014 ◽  
Vol 580-583 ◽  
pp. 3223-3226 ◽  
Author(s):  
Xiao Jie Gu ◽  
Tai Quan Zhou ◽  
Song Cheng
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Soft Soil ◽  
Analysis Model ◽  
Element Analysis ◽  
Consolidation Process ◽  
Full Account ◽  
Finite Element Program ◽  
Modified Cam Clay ◽  
Element Program

The clay layer finite element analysis model , which is established by using finite element program to simulate the embankment filling , takes the intercoupling between water and clay in drainage consolidation process into full account. The use of the effective stress principle consider the characteristics of clay such as nonlinerity , large deformation and so on ,carry out the plane strain finite element analysis on the clay and solve a series of engineering problems.

Numerical Analysis on Vibration Mitigation Effect of EPS Geofoam on Retaining Wall

2010 ◽  
Vol 168-170 ◽  
pp. 1038-1041
Author(s):  
De Ling Wang
Keyword(s):  
Retaining Wall ◽  
Expanded Polystyrene ◽  
Shaking Table ◽  
Finite Element Program ◽  
Physical Test ◽  
Eps Geofoam ◽  
Backfill Soil ◽  
Scale Models ◽  
Element Program ◽  
Rigid Walls

The mitigation of earth force by placing expanded polystyrene (EPS) geofoam buffer between retaining wall and backfill soil under dynamic loading is a topic worth consideration. In this paper, the effects of EPS geofoam buffer on the reduction of thrust wall force are numerically studied to simulate three reduced-scale models of rigid walls using a large shaking table. Numerical simulation technique using the finite element program Abaqus is described. The paper shows that the numerical Abaqus models are able to capture the trend in earth forces with increasing base acceleration for all three models. The use of the EPS geofoam as a compressible buffer yields obviously reduction of the lateral seismic thrust against retaining wall. The quantitative dynamic load–time response of the numerical simulations was in good agreement with measured physical test values.

Friction Force and Stresses Analysis for Contact of Assembled Details

2006 ◽  
Vol 113 ◽  
pp. 334-338
Author(s):  
Z. Dreija ◽  
O. Liniņš ◽  
Fr. Sudnieks ◽  
N. Mozga
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Plastic Deformation ◽  
Friction Force ◽  
Sliding Friction ◽  
Friction Model ◽  
Contact Interface ◽  
Finite Element Program ◽  
Elastic Plastic ◽  
Element Program

The present work deals with the computation of surface stresses and deformation in the presence of friction. The evaluation of the elastic-plastic contact is analyzed revealing three distinct stages that range from fully elastic through elastic-plastic to fully plastic contact interface. Several factors of sliding friction model are discussed: surface roughness, mechanical properties and contact load and areas that have strong effect on the friction force. The critical interference that marks the transition from elastic to elastic- plastic and plastic deformation is found out and its connection with plasticity index. A finite element program for determination contact analysis of the assembled details and due to details of deformation that arose a normal and tangencial stress is used.

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