Application and Validation of Practical Tools for Nonlinear Soil-Foundation Interaction Analysis

2010 ◽  
Vol 26 (1) ◽  
pp. 111-129 ◽  
Author(s):  
Sivapalan Gajan ◽  
Prishati Raychowdhury ◽  
Tara C. Hutchinson ◽  
Bruce L. Kutter ◽  
Jonathan P. Stewart
Keyword(s):  
Interaction Analysis ◽  
Model Performance ◽  
Shallow Foundations ◽  
Winkler Foundation ◽  
Gap Formation ◽  
Foundation Soil ◽  
Lateral Connection ◽  
Practical Guidelines ◽  
Soil Foundation ◽  
The Moment

Practical guidelines for characterization of soil-structure interaction (SSI) effects for shallow foundations are typically based on representing foundation-soil interaction in terms of viscoelastic impedance functions that describe stiffness and damping characteristics. Relatively advanced tools can describe nonlinear soil-foundation behavior, including temporary gap formation, foundation settlement and sliding, and hysteretic energy dissipation. We review two tools that describe such effects for shallow foundations and that are implemented in the computational platform OpenSees: a beam-on-nonlinear-Winkler foundation (BNWF) model and a contact interface model (CIM). We review input parameters and recommend parameter selection protocols. Model performance with the recommended protocols is evaluated through model-to-model comparisons for a hypothetical shear wall building resting on clay and model-data comparisons for several centrifuge test specimens on sand. The models describe generally consistent moment-rotation behavior, although shear-sliding and settlement behaviors deviate depending on the degree of foundation uplift. Pronounced uplift couples the moment and shear responses, often resulting in significant shear sliding and settlements. Such effects can be mitigated through the lateral connection of foundation elements with tie beams.

scholarly journals Simple approach for including foundation–soil–foundation interaction in the static stiffnesses of multi-element shallow foundations

Géotechnique ◽  
2021 ◽  
pp. 1-14
Author(s):  
Jacob David Rodríguez Bordón ◽  
Juan José Aznárez ◽  
Orlando Maeso ◽  
Subhamoy Bhattacharya
Keyword(s):  
Simple Approach ◽  
Shallow Foundations ◽  
Foundation Soil ◽  
Soil Foundation

scholarly journals ON THE MODULUS OF SUBGRADE REACTION FOR SHALLOW FOUNDATIONS ON HOMOGENOUS OR STRATIFIED MEDIUMS

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Lysandros Pantelidis
Keyword(s):  
Elastic Constants ◽  
Shallow Foundations ◽  
Deformation Pattern ◽  
Subgrade Reaction ◽  
Foundation Soil ◽  
Soil Medium ◽  
Modulus Of Subgrade Reaction ◽  
Essential Parameter ◽  
The Moment ◽  
The One

As known, the modulus of subgrade reaction of soil, ks, is an essential parameter in designing flexible, shallow foundations based on the Winkler spring hypothesis, where, the foundation soil is modeled as a series of independent (elastic) springs having constant ks. In this paper the various methods for calculating the ks value are discussed, indicating that the more suitable one is Vesic’s ks=0.65[EB4/(EbIb)]1/12E/[B(1–v2)], where, E and v are the elastic constants of soil and Eb, Ib and B are the modulus of elasticity of the foundation material, the moment of inertial of the cross-section of the foundation and the foundation width respectively. In addition, it is recommended that, the proper soil modulus value is the one corresponding to v=0 for consistency with the deformation pattern of Winkler’s springs (compression with no lateral deformation). In this respect, the author offers an effective method for calculating the equivalent elastic constants (Eeq, veq) for horizontally stratified soil mediums supporting shallow foundations. The same method can also be applied to reducing any homogenous (E, v) soil medium to an equivalent one having veq=0 and modulus Eeq.

scholarly journals Influence of a Thin Horizontal Weak Layer on the Mechanical Behaviour of Shallow Foundations Resting on Sand

Geosciences ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 392
Author(s):  
Maurizio Ziccarelli ◽  
Marco Rosone
Keyword(s):  
Bearing Capacity ◽  
Mechanical Behaviour ◽  
Failure Mechanisms ◽  
Shear Bands ◽  
Ultimate Bearing Capacity ◽  
Shallow Foundations ◽  
Foundation Soil ◽  
Weak Layer ◽  
Geotechnical System ◽  
The Difference

The presence of minor details of the ground, including soil or rock masses, occurs more frequently than what is normally believed. Thin weak layers, shear bands, and slickensided surfaces can substantially affect the behaviour of foundations, as well as that of other geostructures. In fact, they can affect the failure mechanisms, the ultimate bearing capacity of footings, and the safety factor of the geotechnical system. In this research, numerically conducted through Finite Element Code Plaxis 2D, the influence of a horizontal thin weak layer on the mechanical behaviour of shallow footings was evaluated. The obtained results prove that the weak layer strongly influences both the failure mechanism and the ultimate bearing capacity if its depth is lower than two to four times the footing width. In fact, under these circumstances, the failure mechanisms are always mixtilinear in shape because the shear strains largely develop on the weak layer. However, the reduction in the ultimate bearing capacity is a function of the difference between the shear strength of the foundation soil and the layer. The presence of a thin weak layer decreases the ultimate bearing capacity up to 90%. In conclusion, this research suggests that particular attention must be paid during detailed ground investigations to find thin weak layers. Based on the obtained results, it is convenient to increase the soil volume investigation to a depth equal to four times the width of the foundation.

Generalized dynamic Winkler model for nonlinear soil–structure interaction analysis

2008 ◽  
Vol 45 (4) ◽  
pp. 560-573 ◽  
Author(s):  
Nii Allotey ◽  
M. Hesham El Naggar
Keyword(s):  
Soil Structure ◽  
Interaction Analysis ◽  
Soil Structure Interaction ◽  
Winkler Foundation ◽  
Deep Foundations ◽  
Structure Interaction ◽  
Design Engineers ◽  
Winkler Model ◽  
Centrifuge Tests ◽  
Cyclic Degradation

The beam on nonlinear Winkler foundation (BNWF) model is widely used in soil–structure interaction (SSI) analysis owing to its relative simplicity. This paper focuses on the development of a versatile dynamic BNWF model for the analysis of shallow and deep foundations. The model is developed as a stand-alone module to be incorporated in commercial nonlinear structural analysis software. The features of the model discussed are the loading and unloading rules, slack zone development, the modeling of cyclic degradation and radiation damping. The model is shown to be capable of representing various response features observed in SSI experiments. In addition, the predictions of the model for centrifuge tests of piles in weakening and partially weakening soil are shown to be in good agreement with the experimental results. This agreement demonstrates the potential of the model as a useful tool for design engineers involved in seismic design, especially performance-based design.

Beam-on-Nonlinear-Winkler-Foundation Modeling of Shallow, Rocking-Dominated Footings

2009 ◽  
Vol 25 (2) ◽  
pp. 277-300 ◽  
Author(s):  
Chad W. Harden ◽  
Tara C. Hutchinson
Keyword(s):  
Earthquake Engineering ◽  
Energy Content ◽  
Nonlinear Behavior ◽  
Seismic Energy ◽  
Shallow Foundation ◽  
Winkler Foundation ◽  
Soil Foundation ◽  
Performance Based Earthquake Engineering ◽  
Foundation Structure ◽  
Selection Of

The nonlinear behavior of shallow foundations under large amplitude earthquake-induced loading can result in dissipation of seismic energy through the mechanism of soil yielding beneath the foundation. In addition, foundation uplifting may shift the period of the soil-foundation-structure system away from the damaging energy content of most earthquakes. However, this yielding and uplifting may lead to excessive transient and permanent deformations (settlement, rocking, and sliding). Therefore, modeling procedures that account for foundation nonlinearity and uplift are needed before these benefits can be realized in performance based earthquake engineering (PBEE) practice. This paper adopts a beam-on-nonlinear-Winkler-foundation (BNWF) simulation methodology for modeling shallow foundation-structure systems, where seismically-induced rocking plays a predominant role in their response. Numerical results demonstrate that reasonable comparison between the nonlinear Winkler-based approach, and experimental response in terms of moment-rotation, settlement-rotation, and shear-sliding displacement can be obtained, given an appropriate selection of model and soil properties.

scholarly journals Visual tools as mediational means: A methodological investigation

2016 ◽  
Vol 15 (4) ◽  
pp. 359-373 ◽  
Author(s):  
Jaakko Hilppö ◽  
Lasse Lipponen ◽  
Kristiina Kumpulainen ◽  
Antti Rajala
Keyword(s):  
Interaction Analysis ◽  
Embodied Interaction ◽  
Mediated Action ◽  
Visual Research ◽  
Sociocultural Perspectives ◽  
Research With Children ◽  
Material Environment ◽  
Micro Level ◽  
Mediational Means ◽  
The Moment

In this study, we investigated how Finnish children used photographs and drawings to discuss their preschool day experiences in focus groups. Building on sociocultural perspectives on mediated action, we specifically focused on how these visual tools were used as mediational means in sharing experiences. The results of our embodied interaction analysis highlight the relevance of visual tools for the participants and the task at hand in the moment-to-moment, micro-level flow of interaction and its material environment. More specifically, our analysis illuminates different ways in which the visual tools were relevant for participating children and adults when sharing and talking about their experiences. In all, our study advances present-day understanding regarding how sociocultural and embodied interaction frameworks can guide visual research with children.

Dynamic Analysis of an Integrated Train–Bridge–Foundation–Soil System by the Substructure Method

2018 ◽  
Vol 18 (05) ◽  
pp. 1850069 ◽  
Author(s):  
Hong Qiao ◽  
He Xia ◽  
Xianting Du
Keyword(s):  
Dynamic Analysis ◽  
Shear Velocity ◽  
Rigid Body Dynamics ◽  
Dynamic Responses ◽  
Superposition Method ◽  
Foundation Soil ◽  
Soil System ◽  
Substructure Method ◽  
Soil Foundation ◽  
Bridge Foundation

The substructure method is applied to the dynamic analysis of a train–bridge system considering the soil–structure interaction. With this method, the integrated train–bridge–foundation–soil system is divided into the train–bridge subsystem and the soil–foundation subsystem. Further, the train–bridge subsystem is divided into the train and bridge components. The frequency-dependent impedance function of the soil–foundation subsystem is transformed into time domain by rational approximation and simulated by a high-order lumped-parameter model with masses. The equations of motion of the train and bridge components are established by the rigid-body dynamics method and the modal superposition method, respectively. Finally, the dynamic responses of the two subsystems are obtained by iterative procedures, with the influence of the soil shear velocity studied. The case study reveals that it is important to consider the effect of soil–foundation interaction in the dynamic analysis of train–bridge systems, but with the increase of the shear velocity of the soil, such influence becomes weaker.

Study on a New Foundation Stiffness Calculation Model

2012 ◽  
Vol 166-169 ◽  
pp. 1258-1261
Author(s):  
Yan Jun Ma ◽  
Bin Yan ◽  
Jing Zhang
Keyword(s):  
Calculation Model ◽  
Summation Method ◽  
Winkler Foundation ◽  
Foundation Soil ◽  
Foundation Model

This paper combined the feature of Winkler foundation model and base model of limited compressible layer based on the layer-wise summation method, on condition that considering the feature of foundation soil, to derived from a newly foundation stiffness calculation model and to verify it.

SEISMIC SOIL–FOUNDATION–STRUCTURE INTERACTION ANALYSIS OF DEEPLY EMBEDDED VENTILATION STACK

2012 ◽  
Vol 06 (01) ◽  
pp. 1250003
Author(s):  
V. JAYA ◽  
G. R. DODAGOUDAR ◽  
A. BOOMINATHAN
Keyword(s):  
Seismic Response ◽  
Interaction Analysis ◽  
Strong Dependence ◽  
Velocity Ratio ◽  
Relative Displacement ◽  
Response Analysis ◽  
Structure Interaction ◽  
Soil Foundation ◽  
A Site ◽  
Foundation Structure

In this paper, the seismic response analysis of deeply embedded ventilation stack is addressed by considering the effects of soil–foundation–structure interaction (SFSI). Seismic SFSI analysis of the stack subjected to a site-specific design ground motion is carried out using finite element method. A parametric sensitivity analysis is made to investigate the effect of embedment and shear wave velocity ratio of the subsurface profile on the seismic response of the stack. The first series of the SFSI analysis is carried out for the stack with surface footing using computer program SASSI 2000. The second set of analysis incorporates the effect of embedment on the seismic response of the stack. The flexible volume substructure method is used to analyze the seismic SFSI effects. It has been found that the seismic response at the various levels of the stack shows a strong dependence on stiffness of the subsurface profile and the depth of embedment. The spectral acceleration and relative displacement at the top of the stack decrease with increase in embedment ratio and these are the important parameters to be given a due consideration during design process of the stack structures.

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