Foundation Interaction Research Articles

Vibration of subgrade and evaluation of derailment coefficient of train under combined earthquake- moving train load

Vibration response of track and foundation subjected to dynamic loading is one of the key issues to solve on-track safety of high-speed train. The previous pioneering works commonly only considered the train moving load, however, in reality, trains are likely to be on track when an earthquake occurs due to the high frequency and widespread distribution of earthquake activities. Hence, a three-dimensional FEM of track-subgrade- foundation interaction system with bidirectional seismic and moving loads is established for investigating the differences and relations of vibration responses of subgrade in such two immensely disparate loads: train moving load and earthquake-moving load. As a case study, the vibration characteristics of the Beijing-Shanghai High-speed Railway of the China, excited by moving load and seismic-moving composite load are analyzed respectively, with various velocity (v = 50 m/s, 70 m/s, 100 m/s, 130 m/s). On the other hand, the increases in operational train speeds mean that critical velocity effects are becoming more common on high speed rail lines. If unaddressed, critical velocity issues can cause safety concerns and elevated maintenance costs. Based on the derailment coefficient and lateral deformation of the rail, the critical speed of the model is discussed, which is a reasonable improvement to the derailment mechanism of the train.

The Effect of installation Torque on the Behavior of Helical Piles under Compression Load Tested by Centrifuge Device

In complex geotechnical problems, to perform a realistic study related to the soil-structure interaction and bearing capacity of foundations, a centrifuge modeling must be considered. New centrifuge device for installation and testing screw pile models is designed and manufactured with different velocities depending on the value of N (gravity scaling factor) and applying compression, uplift and inclined loads during rotation and their electronic control. The new installation system for helical piles was used in this device to install each pile with different torque depending on its capacity. Helical piles represent one of the deep innovative foundations as an alternative for increasing the size of the existing foundation solutions. In this study, the helical pile models are tested by centrifuge device with different parameters embedded within sand with relative density (R.D) of 75% and 55% under compression load. These parameters are spacing ratio, diameter and number of helices. The installation torque causes a soil disturbance which increases by increasing the diameter of helix and R.D of soil. The reduction percentages of the bearing capacity of the helical pile models with two helices of diameter (40 mm) embedded in sand with R.D of 75% and 55% are 17% and 9%, respectively, and when R.D of (55%) and helix diameters of 40 mm and 50 mm are 9% and 15%, respectively.

Novel Nonlinear Dynamic Beam–Foundation Interaction Model

A nonlinear dynamic framework for the analysis of beam–foundation interaction is developed. The extended Hamilton’s principle is used to analyze the response of Euler–Bernoulli beams vibrating on nonlinear continuums (e.g., soils) and subjected to vibrating and moving loads. The continuum beneath the beam is characterized by a nonlinear elastic constitutive relationship that connects the secant shear modulus to the induced strain. The novel feature of the analysis is that the nonlinear compression and shear parameters ks and ts of the continuum (i.e., foundation) do not have to be assumed a priori, as is required in conventional beams on foundation analysis, and are obtained as part of the solution. In fact, it is shown that these parameters are not constant but change with time and depend on the beam–foundation interaction. Another novel feature of the analysis is that the mass of the foundation participating in the vibration is obtained as part of the solution and does not have to be assumed a priori. Thus, the analysis rigorously takes into account the nonlinear beam–foundation (soil–structure) interaction within a dynamic time-integration framework. The developed framework is as accurate as and about 50% faster than conventional nonlinear dynamic finite element analysis. Inputs to the analysis can be given in the form of a text file without any requirement of numerical mesh generation, making the approach rather user friendly. The characteristics of the developed nonlinear dynamic foundation model are illustrated through examples of moving and vibrating loads.

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

In common engineering practice, foundation–soil–foundation interaction of shallow foundations is frequently ignored. This is presumably for cost/benefit reasons, since computationally demanding finite-element and/or boundary element models are required for that purpose, and its effects are usually assumed to be negligible. In this sense, the present paper provides a simple and inexpensive way of incorporating foundation–soil–foundation interaction through a numerically explicit stiffness matrix formulation. The necessary ingredients for homogeneous and non-homogeneous (shear modulus power-law variation with depth) half-spaces are given. The proposed approach is then applied to offshore wind turbines’ multiple suction caisson foundations (tripod and tetrapod), where it is observed that the foundation–soil–foundation interaction is significant. Its range of validity is also established, and valuable ready-to-use closed-form formulas for the correction factors of the stiffnesses of tripod and tetrapod groups are also derived. The methodology is applicable as long as the spacing between foundations is somewhat greater than the foundation depth.

Fatigue from Culture as a Phenomenon of Sociocultural Life: Problem Statement and General Characteristics

The article explores the phenomenon of culturogenic fatigue. It is currently underresearched but increasingly attracts attention in different areas of sociocultural life. The paper focuses on its main variety: fatigue from culture (FC). The article aims to formulate the FC research problem and to characterize this phenomenon. The author assumes that fatigue from culture is not novel and has been in place throughout the entire history of humankind. And it explains the need for its comprehensive cultural examination. The base for the FC analysis is at the intersection of its phenomenological review and the scrutiny of culturogenic nature and genealogy. Comprehension of specific features of the fatigue from culture phenomenon is possible by comparing biogenic and culturogenic fatigues. It allows for singling out in the latter — along with the tiredness of the body and psyche that exist in their “natural” form — a spiritual and semantic plan, which is substantively and functionally central for it. The author considers the complex dialectic of relations between the FC spiritual content and its psychological forms. It is the FC semantic core taken in unity with its psychological forms (emotional experiences) that breeds the pragmatic of FC, — its spiritually psychological and practical (behavioural) consequences, where the major influence of FC on the consciousness and existence of society and a person reveals itself. The author distinguishes three reasons for the FC birth. The first is conflict-driven relations of natural and cultural principles in society and man, expressed in the repressiveness of culture towards the natural in man, reflected on by Freud. The second one is the peculiarities of the functioning of the culture itself (its recurrence, monotony, etc.), provoking weariness in people, their repulsion from culture. Finally comes the fatigue from the culture itself and its components, which induces fatigue in their actors. In essence, a genetic linkage with a culture determines the place of FC in human lives, specific features of its existence and impact. The article proceeds to consider the essential FC predicates: spatial and temporal in their multidimensionality and unity, and then — dynamic ones. The FC attitude to the movement, which in the light of its sociocultural nature means its attitude to activity, is paradoxical. The article discusses this paradox: fatigue would seem to lead to the vanishing of the activity principle in people tired of culture. But in fact, everything turns out the other way round: based on the negative energy of rejection and repulsion from culture, fatigue transforms into various forms of activity, both mental and practical. The author proposes an explanation of this paradox, rooted in the value-semantic core of FC. The consideration of the dynamic plan of FC also involves reflecting on its important functional feature: the interaction and transitions of the FC different genealogical foundations that create a multilevel and multistage “mechanism of the FC”. This feature generates not only the complexity of the phenomenon but also its special systemic character: the intricate relations of the CF with the sociocultural system of society, kind of irradiation into the chronotopes of the latter.

Rocking forced displacement of a rigid disc embedded in a functionally graded transversely isotropic half-space

Recent studies have confirmed that rockable structures have beneficial effects in earthquakes due to uniform dynamic behavior of the structure. For these kinds of structures, an equivalent static analysis is accurate enough, as the rocking motion is the dominant mode of their interaction with the surrounding soil (i.e. soil–structure interaction problem). In this study, the soil–structure interaction problems are extended to consider the effect of elastic non-homogeneities as well as changing the elasticity constants with depth in an exponential manner for the rocking loads. This paper analytically investigates the mixed boundary value problem regarding the forced rocking interaction of a rigid foundation embedded in a finite depth of an exponentially graded transversely isotropic half-space. The potential function method accompanied by Hankel integral transforms is applied to solve the system of the equations of motion of the media. Due to integral transforms used in the solving procedure, the mixed boundary value problem raised may be apt to be transformed to dual integral equations, which in turn, could be reduced to Fredholm integral equation of the second kind. To evaluate the solution of the integral equations, a robust numerical procedure has been developed for different anisotropic materials. Regarding the complicated integrand functions, the integrals are numerically and graphically presented to cover the effect of degree of change of material properties that plays a key role.

Нравственные начала в жизни общества

The article investigates the influence of moral principles on historically developing social relations. The appeal to this problem is based on a conceptual approach to the origin of human morality, which arises in the course of sociogenesis as a set of behavioral principles that provide the intraspecific cultural (non-genetic) solidarity necessary for human societies. It is noted that the moral consciousness of individuals, which regulates interpersonal relationships, is a necessary but insufficient means for transmitting moral principles. Morality is expressed in the relationship between society and an individual. Society solves the problem of reproduction of moral regulators, it brings them into the nature of social relations by necessity. In this regard, attention is drawn to the role of elite groups in solving the aforementioned problem, in particular, it points out the peculiarities of the formation of an elite layer in Russian history. The elite is the bearer of moral images of social behavior, which expresses the attitude to public goals, interests, historical meanings of social life. The task of the elite is the implementation of these principles in the nature of social relations. The egoism of individuals and social groups can impede the solution of such a problem. Overcoming difficulties of this kind can be achieved by an awareness of history, which provides the basis for public consensus. The article focuses on the ethos of the “spirit of capitalism”, which enters into the social environment through the principles of the organization of economic activity. The paper shows the relevance of the problem of interaction of economic ethics and moral foundations of society as a systemic whole.

Desarrollo Floss y gobernanza de pares: el caso del entorno de escritorio Gnome

Objective of the study: The article analyzes the case of GNOME, one of the most popular Free/ Libre Open Source Software (FLOSS) projects, started in 1997. The concept of peer governance describes the interaction and convergence of companies, foundations, voluntary users and professionals in its development.Methodology/ approach: The research is based on the documentary method and an organizational history approach. For this, primary and secondary digital sources were collected: institutional and FLOSS sites, blogs, community lists, documents and platforms.Originality/ Relevance: The work allows progress, from a sociotechnical perspective, in understanding FLOSS developments and the coevolution of their technical components and community dynamics.Main results: Three levels of governance are identified: 1. the software itself; 2. the community; 3. the ecosystem. Development cycles; community participation and organization; actors and business models, definitions and controversies, are analyzed. GNOME's trajectory is marked by the confluence of interests and coopetition between corporate actors and the FLOSS ecosystem. The life cycle shows a constant activity, which implies redefinition of its components, technological infrastructure and leadership. It is not exempt from controversies and bifurcations, similar to those evidenced in projects of this type.Theoretical/ methodological contributions: It contributes to the concept of peer governance and its usefulness for case analysis. Reflection on data sources and research resources on the Internet is promoted.Social/ managerial contributions: It contributes to the understanding of new forms of management and decision-making in technological development projects.

Centrifuge modeling of single pile-shallow foundation interaction in reverse fault

Both pile foundations and shallow foundations are deemed to be vulnerable to significant fault deformation. However, the pile foundation-shallow foundation interaction in dip-slip fault has never been studied, to the authors' knowledge. This study presents the results of two centrifuge tests, in which a shallow foundation and single piles are subjected to reverse faulting. The tests are compared with the ones from previous studies in the following conditions: free-field, with only a shallow foundation, and with only single piles. The results show that there is a significant interaction between the single piles and shallow foundations. The presence of single piles leads to larger displacements and rotations of shallow foundations. The shallow foundation affects the pile behaviors in two ways: 1) the rupture diversion caused by the shallow foundation leads to different magnitudes and distributions of soil displacements along the piles; 2) the shallow foundation prevents the free deformation of soil, resulting in increasing soil stress even after outcropping.

THE PROBLEM OF TRADITION IN MODERN ARCHITECTURE

It has been established that the traditional approach in architecture should be considered as a socially and aesthetically determined phenomenon; the issues of implementing the capabilities of the traditional approach are considered in the context of the goals and objectives of contemporary architectural creativity.The problems of evolution of the "folk" architectural tradition are considered together with architectural activity, and a principled analytical approach to its implementation.Using the criteria for the systematization of architectural theory, attention is focused on the stages of development of ideas about tradition in architecture, due to the growth of the socio-cultural significance of the original approach to architecture and the manifestation of traditions in architectural creativity.At the beginning of the twentieth century, traditionalist philosophers spoke of the crisis of a crushed, positivist, mechanical-quantitative science. They called for a return to a new level to a pre-scientific, syncretic view of the world. Moreover, this unifying way of thinking must choose the naive manner of speech inherent in life and at the same time use it in proportion to how it is necessary for the evidence of evidence. This «naivety of language», which clearly expresses clear thoughts, today is sorely lacking in architecture studies, which are replete with new terms, but often suffer from blurred content.Innovation, which at first denied the tradition of historicism, soon becomes a «tradition» itself. However, after spending a long period in his clothes, it then strives back into the bosom of historicism, and it can be qualified as a new and daring innovation. Today you can find such examples when, tired of the dominance of «glass» architecture, you can suddenly see a return to the classics, which you just want to call an innovation.Actualization of the ideas of traditional originality in modern architecture is conditioned by specific tasks and prerequisites and is a natural stage in the evolution of world architecture. At the same time, the problem of dialectical interaction of traditional and modern foundations in architecture is obvious; a problem that is becoming more acute as the methods, capabilities and goals of the construction industry change.

Use of Vertical and Inclined Walls to Mitigate the Interaction of Reverse Faulting and Shallow Foundations: Centrifuge Tests and Numerical Simulation

AbstractThis research introduces a new effective approach, including a weak vertical wall (WVW) and a strong inclined wall (SIW) under a shallow foundation, to reduce the rotations caused by a faul...

Classification of Variable Foundation Properties Based on Vehicle-Pavement-Foundation Interaction Dynamics.

The dynamic interaction between vehicle, roughness, and foundation is a fundamental problem in road management and also a complex problem, with their coupled and nonlinear behavior. Thus, in this study, the vehicle–pavement–foundation interaction model was formulated to incorporate the mass inertia of the vehicle, stochastic roughness, and non-uniform and deformable foundation. Herein, a quarter-car model was considered, a filtered white noise model was formulated to represent the road roughness, and a two-layered foundation was employed to simulate the road structure. To represent the non-uniform foundation, stiffness and damping coefficients were assumed to vary either in a linear or in a quadratic manner. Subsequently, an augmented state-space representation was formulated for the entire system. The time-varying equation governing the covariance of the response was solved to examine the vehicle response, subject to various foundation properties. Finally, a linear discriminant analysis method was employed for classifying the foundation types. The performance of the classifier was validated by test sets, which contained 100 cases for each foundation type. The results showed an accuracy of over 90%, indicating that the machine learning-based classification of the foundation had the potential of using vehicle responses in road managements.

Analytical formulation and finite-element implementation technique of a rigorous two-parameter foundation model to beams on elastic foundations

ABSTRACT A simple way of computer implementation of an effective two-parameter subgrade model for the routine analysis of flexible foundations on an elastic subgrade is presented. It is based on a rigorous analytical subgrade model recently proposed by one of the authors that takes full account of the soil–structure interaction. The details of both finite element (FE) and analytical implementation of the model to beams are presented. Fully established closed-form relationships are provided for the subgrade parameters. The essence in the method is that the soil shear resistance within the loaded region is transferred to the foundation element as an additional rigidity in form of a geometric stiffness, thereby leaving the Winkler spring bed to take care of the vertical compression as accustomed. Additional edge springs are introduced to account for the edge forces due to the shear continuity extending beyond the edges. By so doing, the attractiveness of the long-enduring Winkler’s model is maintained, whereas the missing shear interaction is taken care of through the introduction of the geometric stiffness and the edge springs. The FE discretisation is thus limited to the foundation unit alone as initially intended. Subject classification codes: soil–foundation interaction

Vibration of Timoshenko Beam-Soil Foundation Interaction by Using the Spectral Element Method

This article presents an analysis of free vibration of elastically supported Timoshenko beams by using the spectral element method. The governing partial differential equation is elaborated to formulate the spectral stiffness matrix. Effectively, the non classical end boundary conditions of the beam are the primordial task to calibrate the phenomenon of the Timoshenko beam-soil foundation interaction. Non-dimensional natural frequencies and shape modes are obtained by solving the partial differential equations, numerically. Upon solving the eigenvalue problem, non-dimensional frequencies are computed for the first three modes of vibration. Obtained results of this study are intended to describe multiple objects, such as: (1) the establishment of the modal analysis with and without elastic springs, (2) the quantification of the influence of the beam soil foundation interaction, (3) the influence of soil foundation stiffness’ on free vibration characteristics of Timoshenko beam. For this propose, the first three eigenvalues of Timoshenko beam are calculated and plotted for various stiffness of translational and rotational springs.

A Winkler-based model for inelastic response of soil–structure systems with embedded foundation considering kinematic and inertial interaction effects

In this paper, a parametric study is carried out on the ductility and displacement demands of structures with embedded foundation considering nonlinear soil–structure interaction (SSI). The soil–embedded foundation interaction is simulated using the beam on Winkler foundation concept. The bilinear behavior is also assumed for the equivalent single-degree-of-freedom (SDOF) structure. Effect of key parameters including fundamental period, level of inelasticity, soil flexibility, embedment ratio, and slenderness ratio on the seismic demands is examined. A family of soil–structure systems are analyzed subjected to a group of 33 ground motions recorded on alluvium deposits. Both sway and rocking components of foundation input motion are applied to the system. Results reveal that foundation embedment generally increases the ductility demand of the SDOF system. Moreover, the kinematic interaction (KI) effect on ductility demands is more prominent for structures with deep embedment ratios. As the aspect ratio increases, the role of rocking input motion on ductility and displacement demands becomes more noticeable. It is also concluded that the nonlinear SSI can increase the displacement demand of interacting systems as compared to the equivalent linear soil model. Based on the obtained results, a simplified expression is proposed to estimate the displacement ratio for soil–structure systems with embedded foundation considering KI effects.

An Investigation of the Seismic Interaction of Surface Foundations and Underground Cavities Using Finite Element Method

In this study, the seismic interaction of surface foundations and underground cavities was investigated. For this purpose, a parametric study of geometric dimensions of the foundation and cavity, their location, and the effect of the interaction between surface foundations and underground cavities was evaluated. The variable parameters include the ratio of the overburden height to the foundation width (H/B = 0.5, 1 and 2), the location ratio of the cavity to the foundation width (X/B=0, 2 and 8) and the ratio of the cavity diameter to the foundation width (d/B=0.5, 1 and 2), respectively. The accuracy of the finite element method was evaluated using a laboratory study and it was found that the used method provides an accurate prediction of tunnel behavior.The results indicated that by increasing the overburden height, the stress on the tunnel surfaces was increased for all values of X/B (the horizontal tunnel distance to the foundation width). Therfore, in the case where the tunnel is located exactly along the center at the bottom of the foundation (X/B=0, d/B=2), the maximum stress generated is approximately 2.13 times greater than its corresponding value in the ratio of the depth to width of 0.5 (X/B=0, d/B=0.5). It can be concluded that the higher overburden height, the greater stresses caused by the dynamic loads of the earthquake on the tunnel wall.

Effect of the Directional Components of Earthquakes on the Seismic Behavior of an Unanchored Steel Tank

This paper investigates the effect of the multi-directional components of ground motion on an unanchored steel storage tank. Both the liquid sloshing effect and contact behavior between the foundation and tank are included in the study. A three-dimensional model for a foundation–structure–liquid system is numerically simulated using the finite element method. The Lagrange fluid finite element method (FEM) in ANSYS is used to consider the liquid–solid interaction. In the liquid–structure–foundation interaction model, the contact and target elements are adapted to simulate the nonlinear uplift and slip effects between the tank and the foundation. Three earthquake ground motions are selected for evaluating the seismic behavior of the tank. Comparisons are made on the horizontal displacement, “elephant-foot” deformation, stress, base shear and moment, sloshing of the liquid, uplift, as well as slip behavior under the application of the unidirectional, bi-directional and tri-directional components. Under the selected ground motions, the horizontal bi-directional seismic component has great influence on the liquid sloshing in the tank studied in this paper. The vertical seismic component produces high compressive axial stress, and it also makes the uplift and slide of the tank bottom increase significantly. The applicability of this conclusion should be carefully considered when applied to other types of ground motion inputs.

Centrifuge modelling of a tetrapod jacket foundation under lateral cyclic and monotonic loading in soft soil

The tetrapod jacket foundation is one of the most common types of foundations used for offshore structures. Although the static bearing capacity of the jacket foundation is important, a safe design must be taken into consideration for accumulative deformation and stiffness degradation during cycling. To address this, a set of centrifuge model tests of a tetrapod jacket foundation subjected to cyclic and monotonic loading was conducted in kaolin. The test results mainly reveal (i) the influence of loading history on the lateral bearing capacity of the jacket foundation; (ii) the evolution of accumulative deformation of the jacket foundation during cycling; (iii) the stiffness degradation of soil–pile interaction under cyclic loading. Comparing typical “lateral soil resistance”–“pile lateral displacement” (p–y) curve approaches with test results, a hyperbolic tangent p–y curve method is adopted to calculate the soil–pile interaction of the jacket foundation. The values of the p-multipliers of leading-row and trailing-row piles in soft soils are clearly lower than that in sands. Finally, a cyclic p–y curve method related to cycles and embedded depths is developed for the jacket foundation in the hope of providing guidance for the design of the jacket foundation in soft soil.

Field monitoring of the ground vibrations adjacent to an onshore wind turbine foundation

Investigations of the soil–foundation interaction behaviour of wind turbine foundations and transfer of energy from the wind to the ground have not been reported in Canada. Indeed, very few vibration monitoring studies have been conducted globally around wind farms. It has been found that turbines predominantly produce vibrations related to structural resonances and blade-passing frequencies. Energy is found to be modified with distance and is dominated by surface waves. This paper describes a study of the effect of wind–structure interaction on the behaviour of a turbine foundation and the generation of ground-based vibrations around a working commercial wind turbine in Ontario. The field monitoring system and meteorological instrumentation are described in this paper and the responses of the structure and surrounding ground due to the fluctuating wind-field are discussed. The spectral analysis shows that the higher frequency vibrations attenuate more rapidly than the lower frequency vibrations. The tilted elliptical particle motions are found to be non-Gaussian because of the non-Gaussian wind conditions. The response attenuation with distance indicates that both geometric and material attenuation may dominate the vibration attenuation in the near field and only geometric attenuation occurs in the far field.

Study on the Comprehensive Method of Crack Control in Engineering Structure

It is a very complex and important problem that cracks of engineering structure are caused by deformation (hydration heat, shrinkage, temperature difference). The author in the accumulation of a large number of construction and crack processing experience and theoretical research, on the basis of combination of existing computer network technology, is proposed based on computer technology of the engineering structure crack control synthesis method, including the approximate calculation method of structural mechanics, structure and foundation interaction, construction technology and the optimization of material, environmental conditions, etc.