Showing papers on "Soil structure interaction published in 1993"
TL;DR: In this paper, dimensionless parametric graphs for pile bending moments are presented which pertain to characteristic two-layer soil profiles, which are derived by using an existing rigorous dynamic finite-element code, and by implementing a realistic beam-on-dynamic-Winkler-foundation formulation specifically developed for the kinematic response of piles in layered soil.
Abstract: The paper studies the kinematic response of freehead piles. Such pile deformation has triggered structural damage in many strong earthquakes. In this Paper dimensionless parametric graphs for pile bending moments are presented which pertain to characteristic two-layer soil profiles. The results are derived by using an existing rigorous dynamic finite-element code, and by implementing a realistic beam-on-dynamic-Winkler-foundation formulation specifically developed for the kinematic response of piles in layered soil. The Winkler model is shown to reproduce quantitatively even detailed trends observed in the finite-element results; a simple analytical expression is thereby developed for estimating the Winkler stiffhess in terms of the local soil Young’s modulus and key dimensionless pile/ soil parameters. The study concludes that even relatively flexible piles may not exactly experience the wavy and abruptly changing ground deformation of the free field. The critical region of pile distress due to such kinematic loading is shown to he at or near the interface between alternating soft and stiff soil layers. The magnitude of the bending moment at such critical interface locations depends mainly on the stiffness contrast of the two layers through which the pile penetrates, the excitation frequency and the relative rigidity of the pile. A constraining cap may exert an important effect on such kinematic deformations.
170 citations
TL;DR: In this article, a general procedure is presented to study the dynamic soil-structure interaction effects on the response of long-span suspension and cable-stayed bridges subjected to spatially varying ground motion at the supporting foundations.
Abstract: A general procedure is presented to study the dynamic soil–structure interaction effects on the response of long-span suspension and cable-stayed bridges subjected to spatially varying ground motion at the supporting foundations. The foundation system is represented by multiple embedded cassion foundations and the frequency-dependent impedance matrix for the multiple foundations system takes into account also the cross-interaction among adjacent foundations through the soil. To illustrate the potential implementation of the analysis, a numerical example is presented in which the dynamic response of the Vincent–Thomas suspension bridge (Los Angeles, CA) subjected to the 1987 Whittier earthquake is investigated. Although both kinematic and inertial effects are included in the general procedure, only the kinematic effects of the soil–structure interaction are considered in the analysis of the test case. The results show the importance of the kinematic soil–foundation interaction on the structural response. These effects are related to the type, i.e. SH-, SV-, P- or Rayleigh waves and to the inclination of the seismic wave excitation. Moreover, rocking components of the foundation motion are emphasized by the embedment of the foundation system and greatly alter the structural response.
37 citations
TL;DR: In this paper, a three-dimensional visco-elastic finite element formulation for studying the interactive behaviour of space frames, taking into account the stress/strain-time response of supporting soil medium is presented.
34 citations
TL;DR: In this article, a mathematical model for a combined soil subgrade plus structural elements in contact with the subgrade (e.g., a mat foundation) is presented, which can be visualized as a spring-supported beam column under constant axial tension.
Abstract: A mathematical model for a combined soil subgrade plus structurallement in contact with the subgrade (e.g., a mat foundation) is presented. The structural portion of the model is a conventional flexural element. The subgrade portion of the model is Pasternak's hypothesis, which is fundamentally more accurate than the commonly used Winkler hypothesis. The novel element developed in this note is not the individual model components, but the fact that the combined model can be visualized as a spring‐supported beam‐column under constant axial tension. The column tension and springs represent the subgrade effects. This beam‐column analogy is useful in practice because it allows more accurate modeling of soil‐structure interaction within the capabilities of existing structural analysis computer software.
29 citations
TL;DR: In this paper, the authors studied the relations between earthquake motions recorded from two adjacent, seven-story buildings, from a downhole below the foundation of one of the buildings, and found that the two buildings were connected.
Abstract: Presented in this part of the twopart paper is a study of the relations between earthquake motions recorded from two, adjacent, sevenstory buildings, from a downhole below the foundation of one of ...
25 citations
TL;DR: In this article, the dynamic behaviour of a tower structure founded on a saturated sand bed subjected to model earthquakes was investigated using the bumpy road-shaking system of the Cambridge centrifuge.
Abstract: The dynamic behaviour of a tower structure founded on a saturated sand bed subjected to model earthquakes was investigated using the bumpy road-shaking system of the Cambridge centrifuge. Excess po...
23 citations
TL;DR: In this article, a consistent formulation of the problem equally applicable to both methods can be achieved in which true nonlinear behaviour of the bounded soil zone (near-field) can be taken into account in the time domain through properly defined constitutive models.
22 citations
01 Sep 1993
TL;DR: In this paper, the results of a soil-structure interaction analysis of a potentially permanent, low-maintenance solution to siltation in the Red River Waterway were presented.
Abstract: : Lock and Dam No. 1 on the Red River Waterway has experienced a serious siltation problem since its completion in 1983. This technical report summarizes the results of a soil-structure interaction analysis of a potentially permanent, low-maintenance solution to this problem, i.e., construction of a reinforced soil retaining wall adjacent to the riverside lock wall. The principal objective of this research was to assess potential lock performance after construction of a reinforced soil retaining wall adjacent to the riverside lock wall. Due to the nature of the problem, the conventional analysis techniques, which are based upon the equations of equilibrium and used in the design of reinforced soil retaining walls, did not provide sufficient information to satisfactorily evaluate performance of this structure with regard to its interaction with the lock and the surrounding foundation soil strate. The general purpose, nonlinear, incremental construction, finite element computer program, SOILSTRUCT was used to analyze the complex soil-structure interaction by simulating the staged construction. Earth pressures, Soil reinforcement, Finite elements, Soil-structure interaction.
20 citations
TL;DR: In this paper, the effect of the flexibility of the foundation beam on the entire interactive behaviour of a plane frame combined footing-soil mass system has been considered, and coupled finite-infinite element formulation has been adopted for the physical representation of the system.
19 citations
01 Jan 1993
TL;DR: In this article, the conventional direct frequency or time domain boundary element method is applied to dynamic soil-structure interaction analysis, where both the structure and the soil are assumed to be homogeneous, isotropic and linear elastic or viscoelastic bodies under two- or three-dimensional conditions.
Abstract: The conventional direct frequency or time domain boundary element method as applied to dynamic soil-structure interaction analysis is discussed. Both the structure and the soil are assumed to be homogeneous, isotropic and linear elastic or viscoelastic bodies under two - or three - dimensional conditions. The dynamic disturbances may be externally applied loads or seismic waves of an arbitrary spatial and temporal variation. The effects of inhomogeneity and anisotropy of soil on the system response are also considered. Applications including the dynamics of foundations and above ground structures and the dynamic response of underground structures are described in detail. The general conclusion is that the boundary element method alone, or coupled with the finite element method, is ideally suited for dynamic soil-structure interaction problems from both the accuracy and efficiency viewpoints.
17 citations
TL;DR: In this paper, the authors analyzed the dynamic response of deeply embedded structures, such as underground tunnels and deep foundations, in a multilayered elastic half-space, when the structure is excited by a plane P or SV wave propagating at some angle.
Abstract: Dynamic response of deeply embedded structures, such as underground tunnels and deep foundations, in a multilayered elastic half-space are analysed when the structure is excited by a plane P or SV wave propagating at some angle. The scattered field is represented by the sum of three Green's functions, corresponding to two oscillating forces and one oscillating moment at the centroid position of the buried structure. The amplitudes of these two forces and one moment are a priori unknown and are obtained by satisfying displacement and stress continuity conditions across the near-field/far-field boundary. The distinguishing feature of this technique from direct or indirect boundary integral techniques is that in these techniques a distribution of sources of unknown amplitude are considered at the near-field/far-field boundary, and a large number of sources are needed for different combinations of source-receiver arrangements. But in this technique the sources of unknown amplitude are placed at the location of the structure, not at the near-field/far-field boundary and, using the Saint Venant's principle, the scattered field is modelled. Thus, the number of sources required is reduced to only three. Two example problems are solved. The first one is for a deeply embedded footing in a three-layer soil mass and the second one is for a rectangular tunnel in a two-layer soil mass.
01 Jan 1993
TL;DR: The principal effects of soil-structure interaction on the dynamic response of ground-excited systems are identified and information and concepts are presented with which these effects may be provided for rationally and cost-effectively in design.
Abstract: The principal effects of soil-structure interaction on the dynamic response of ground-excited systems are identified, and information and concepts are presented with which these effects may be provided for rationally and cost-effectively in design. Both kinematic and inertial actions are examined. The concepts involved are developed by reference to relatively simple structures, but their application to more involved systems is also highlighted. In addition, a brief account is given of the application of some of these concepts in the formulation of appropriate seismic design provisions for building structures.
TL;DR: In this article, the authors presented two simplified methods for the dynamical analysis of the response of frame-wall plane systems interacting with the foundation soil, based on approximations widely used in the literature and form an extension of those already presented by the authors for structures on rigid soil.
TL;DR: In this paper, a robust active optimal control scheme for the vibration control of a seismically excited structure is presented for soft soils, where the effect of soil-structure interaction is prominent.
Abstract: A robust active optimal-control scheme is presented for the vibration control of a seismically excited structure. The conventional optimal-regulator-control scheme for civil engineering structures with fixed-base assumption and without an observer is found to be quite ineffective for soft soils, where the effect of soil-structure interaction is prominent. A new algorithm is developed including the effect of soil-structure interaction in which soil is represented by the frequency-independent springs and dampers. The effect of the variation of soil parameters on the control scheme is taken into account by the introduction of an observer. An acceleration-type observer is used, which minimizes the difference of accelerations between the real structure and the mathematical model. The scheme is found to be robust for a considerable range of variation in the soil stiffness. The system involves an inherent instability due to the effect of observation spillover, which is corrected by prefiltering the sensor data. On the other hand, no control spillover is observed.
TL;DR: In this article, the influence of structural stiffness on soil consolidation has been investigated, and the effect of the change in structure forces on the process of consolidation has also been considered. But the authors focused on the impact of the structural stiffness of the soil on the settlement caused by cohesive soil consolidation.
Abstract: Several papers have been written about the influence of structural stiffness on soil consolidation. Most dealt with the soil as an elastic-medium, flexible beam on a Winkler medium with adequate interface finite element between the structure and soil, foundation element stiffness matrix, and three-phase spatial structure. The present technical note considers the effect of settlement caused by cohesive soil consolidation on the structure and the effect of the change in structure forces on the process of consolidation. It also considers the direct pressure from the foundation on the soil, as well as the pressure spread according to Boussinesq's equation from one foundation to another.
TL;DR: In this paper, the authors discuss the effect of different types of transformations on the performance of a person's home environment and their ability to adapt to changes in the environment, such as:
Abstract: 本研究は, 有限要素法を用いた3次元構造物-地盤系の非線形地震応答解析について検討するものである. 材料非線形の解法として荷重伝達法を用いる場合の降伏要素の応力の補正方法として, 材料を弾性と仮定して求まる応力に比例定数を乗じて, 降伏後の要素の主応力が降伏規準面上に留まるように比例定数を決定する方法を提案する. また, 境界処理方法として, 構造物からある程度離れた地盤では自由地盤として独立に求めた応答と等しく既知であるとして解析する方法を提案する.
01 Jan 1993
TL;DR: The use of finite element method in soil-structure interaction analysis dictates that the infinite soil medium be truncated along a certain boundary, called artificial boundary, separating the soil structure system into near and far fields.
Abstract: The use of finite element method in soil-structure interaction analysis dictates that the infinite soil medium be truncated along a certain boundary, called artificial boundary, separating the soil-structure system into near and far fields. In conjunction with the analysis of near field, some artificial boundaries capable of transmitting waves from near to far field are proposed in literature. In the present study, first these artificial boundary conditions are reviewed, and then they are assessed by using some chosen sample problems. The comparisons are presented in both time and frequency spaces.
01 Jan 1993
TL;DR: In this paper, the stiffness and damping influence coefficients of a rectangular foundation embedded into a damped half plane are derived for the stiffness problem of embedded foundations, the determination of Green functions in unexcavated, virgin soil condition and the subsequent subtraction of the excavation zone are the two main steps of the analysis concept called Analytical Excavation.
Abstract: The development of soil-structure interaction during the last quarter of a century has followed two distinctive paths yielding the Direct and Substructure Methods of analysis. In current state-of-the-art both methods are represented by quite similar models with differences being restricted to the dynamic boundary conditions defined along the boundary of the finite soil region considered. Therefore achieving a common formulation equally applicable to both methods is possible. Within the framework of Substructure Method, the Boundary Element Method has been very effective in handling geometrically irregular conditions at the soil-structure interface. For the stiffness problem of embedded foundations, the determination of Green functions in unexcavated, virgin soil condition and the subsequent subtraction of the excavation zone are the two main steps of the analysis concept called Analytical Excavation. Effective input motions of flexible and rigid foundations are easily obtained once the dynamic stiffness and free-field response of virgin soil are known. Examples presented are the stiffness and damping influence coefficients as well as the components of effective base input motion of a rectangular foundation embedded into a damped half plane.
Dissertation•
01 Dec 1993
TL;DR: In this article, a semi-analytical method is developed to compute the response of a rigid footing subjected to a harmonic excitation and resting on a layered soil deposit with a noncompliant rock or rock-like material at the base.
Abstract: A simple semi-analytical method is developed to compute the response of a rigid footing subjected to a harmonic excitation and resting on a layered soil deposit with a noncompliant rock or rock-like material at the base. The method is based on variational principles and minimization of energy using Hamilton's principle. Nondimensional equations are developed for a rigid strip and circular footings resting on a layered soil media with constant or variable modulus lying on a rigid rock at the base. The method is relatively simple to use and has the ability to provide variable elastic modulus of the soil with depth. Dynamic response characteristics are plotted using nondimensional parameters.
01 Jan 1993
TL;DR: The purpose of the paper is to explain the interaction analyses in the context of typical structural dynamics analysis procedures.
Abstract: In this paper, the sequence of significant developments in the methods of analysis of dynamic earthquake interaction between structures and their foundation media is outlined. The development is divided into four phases, starting with a rigid foundation medium where there is no interaction with the structure and ending with a description of the frequency domain response analysis of a structure on a continuum foundation system. The purpose of the paper is to explain the interaction analyses in the context of typical structural dynamics analysis procedures.
TL;DR: In this article, a simple numerical model is proposed to model the effect of liquid sloshing in tank, and the governing equations are derived for the response of ground-supported cylindrical tank filled with liquid.
Abstract: Large pressure exerting on soil due to dynamic response of a liquid storage tank may cause excessive settlement to the supporting soil. Analysis for the dynamic response of such a system should consider the sloshing of liquid in the tank, the associated hydrodynamic pressure, and the coupling effects of liquid with tank and soil foundation. In this study, a simple numerical model is proposed to model the effect of liquid sloshing in tank. The governing equations are derived for the response of ground-supported cylindrical tank filled with liquid. It is found that liquid sloshing is dominated by the first mode of motion. Based on this fact, a closed-form solution is obtained to study the pressures exerted on soil due to harmonic excitation. The dynamic response of the system is examined for various tank sizes, height-radius ratios, and soil properties. It is found that resonance of such a system occurs due to sloshing of liquid under slow excitation. Under higher frequency excitation, such as that of earthquakes, the effect of liquid also plays an important role in the response of the liquid-tank-soil system
TL;DR: In this paper, a modified lumped parametric model for the analysis of nonlinear soil-structure interaction (SSI) effects has been proposed, where both inelastic soil behavior and loss of contact between the foundation and the surrounding soil are taken into account.
01 Jan 1993
16 Sep 1993
TL;DR: In this paper, the sensitivity of the predicted seismic response of buildings in a PWR nuclear power station to the potential changes in the techniques and methods of interpreting soil data that have occurred over the last decade was investigated.
01 Feb 1993
TL;DR: In this paper, the use of a tension tie reinforcement in the slabs under arches under high fill was a wise and proper decision, as the tension strains in the floor indicate that the bars developed significant strains.
Abstract: Observations of soil pressures and strains in arch components over a 5-year period indicate that: (1) The design procedure used for arch segments produced components that have supported imposed soil and environmental forces successfully. (2) The use of a tension tie reinforcement in the slabs under arches beneath high fill was a wise and proper decision, as the tension strains in the floor indicate that the bars developed significant strains. (3) Vertical earth pressures exceeded the nominal amount determined for uncompacted density and depth. Measured pressures imply a soil density in the order of 130 pcf. (4) Creep deformations in concrete must be included in analytic procedures in order to obtain displacement responses corresponding to those measured. (5) The redundancies associated with soil-structure interaction tend to produce favorable redistributions of resistance to soil loads against the arch. (6) A sophisticated analytic model of the structural system was shown to produce stress and displacement values very similar to those measured. The analytic model must include specific data regarding soil properties and creep response time effects for concrete as well as for soil.
01 Jan 1993
TL;DR: In this article, the governing equations for the earthquake analysis of saturated porous media and the cyclic constitutive model for the soil skeleton are described and implemented with consideration of the boundary and interface conditions.
Abstract: Review of the governing equations for the earthquake analysis of saturated porous media and the cyclic constitutive model for the soil skeleton are described. The mathematical formulation is implemented with consideration of the boundary and interface conditions. An example is presented for the analysis of an earth dam subjected to seismic loading.
01 Jan 1993
TL;DR: In this article, the authors considered the structural response of seismic ground motions considering structure-foundation interaction and formulated the governing equations of the motion in terms of random vibration or by means of simulated motions and FFT.
Abstract: Characteristics, description and effects on structural response of spatial incoherence of seismic ground motions are treated considering structure-foundation interaction. Governing equations of the motion are formulated and solved either in terms of random vibration or by means of simulated motions and FFT. Examples involving a concrete gravity dam and buried pipelines are given.