• Title, Summary, Keyword: kinematic soil-structure interaction

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Soil-structure interaction and axial force effect in structural vibration

  • Gao, H.;Kwok, K.C.S.;Samali, B.
    • Structural Engineering and Mechanics
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    • v.5 no.1
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    • pp.1-19
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    • 1997
  • A numerical procedure for dynamic analysis of structures including lateral-torsional coupling, axial force effect and soil-structure interaction is presented in this study. A simple soil-structure system model has been designed for microcomputer applications capable of reflecting both kinematic and inertial soil-foundation interaction as well as the effect of this interaction on the superstructure response. A parametric study focusing on inertial soil-structure interaction is carried out through a simplified nine-degree of freedom building model with different foundation conditions. The inertial soil-structure interaction and axial force effects on a 20-storey building excited by an Australian earthquake is analysed through its top floor displacement time history and envelope values of structural maximum displacement and shear force.

Stochastic analysis of seismic structural response with soil-structure interaction

  • Sarkani, S.;Lutes, L.D.;Jin, S.;Chan, C.
    • Structural Engineering and Mechanics
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    • v.8 no.1
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    • pp.53-72
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    • 1999
  • The most important features of linear soil-foundation-structure interaction are reviewed, using stochastic modeling and considering kinematic interaction, inertial interaction, and structural distortion as three separate stages of the dynamic response to the free-field motion. The way in which each of the three dynamic stages modifies the spectral density of the motion is studied, with the emphasis being on interpretation of these results, rather than on the development of new analysis techniques. Structural distortion and inertial interaction analysis are shown to be precisely modeled as linear filtering operations. Kinematic interaction, though, is more complicated, even though it has a filter-like effect on the frequency content of the motion.

Seismic Response of Structure on Flexible Foundation (유연한 기초 위에 세워진 구조물의 지진거동)

  • 김용석
    • Journal of the Earthquake Engineering Society of Korea
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    • v.1 no.1
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    • pp.11-17
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    • 1997
  • Seismic analyses of structures were carried out in the past assuming a right base and Ignoring the characteristics of foundations and the properties of the underlying soil. Resent soil-structure interaction studies show that seismic response of structure can be affected significantly by these fators. Typical effects of the soil-structure interaction are the kinematic interaction of a rigid massiess foundation and the inertial interaction between underlying soil and structure. The kinematic interaction effect is particularly important for embedded foundations and can be ignored for surface foundations with vertically propagating waves. In this study, seismic response of structure was investigated with four buildings in Mexico City considering only the inertial interaction effect and using the E-W components of the 1985 Mexico City earthquake records. The study was carried out for surface foundations and pile foundations with linear and nonlinear soil conditions, comparing the results with those of the rigid base.

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Extracting Foundation Input Motion Considering Soil-Subterranean Level Kinematic Interaction (지하층-지반 운동학적 상호작용을 고려한 기초저면의 설계지반운동 산정)

  • Sadiq, Shamsher;Yoon, Jinam;Kim, Juhyong;Park, Duhee
    • Journal of the Korean GEO-environmental Society
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    • v.19 no.11
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    • pp.31-37
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    • 2018
  • Most of tall building systems are composed of above-ground structure and underground structure used for parking and stores. The underground structure may have a pronounced influence on tall building response, but its influence is still not well understood. In a widely referred report on seismic design of tall buildings, it is recommended to model the underground structure ignoring the surrounding ground and to impose input ground motion calculated considering the underground structure-soil kinematic interaction between at its base. In this study, dynamic analyses are performed on 1B and 5B basements. The motions at the base are calculated to free field responses. The motions are further compared to two procedures outlined in the report to account for the kinematic interaction. It is shown that one of the procedure fits well for the 1B model, whereas both procedures provide poor fit with 5B model analysis result.

Seismic Analysis of Underground RC Structures considering Interface between Structure and Soil (경계면 요소를 고려한 지하 철근콘크리트 구조물의 지진해석)

  • 남상혁;변근주;송하원;박성민
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.87-92
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    • 2000
  • The real situation of an underground reinforced concrete(RC) structure with the surrounding soil medium subjected to seismic load is quite difficult to be simulated through an expensive work and, even if it is possible to arrange such an experiment, it will be too expensive. So development of analytical method can be applied usefully to seismic design and seismic retrofit through an analysis of seismic behavior and seismic performance evaluation. A path-dependent constitutive model for soil that can estimate the response of soil layer is indispensible for dealing with kinematic interaction of RC/soil entire system under seismic loads. And interface model which deals with the dynamic interaction of RC/soil entire system is also necessary. In this study, finite element analysis program that can consider path-dependent behavior of RC and soil, and interfacial behavior between RC and soil is developed for rational seismic analysis of RC/soil entire system. Using this program, nonlinear behavior of interface between RC and soil is analyzed, and the effect of interfacial behavior to entire system is investigated.

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Study on the Dynamic Characteristics of Foundation-Soil System for the Seismic Analysis of Structures (구조물 내진설계를 위한 기초지반체계 동특성에 관한 연구)

  • 김용석
    • Journal of the Earthquake Engineering Society of Korea
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    • v.1 no.3
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    • pp.1-10
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    • 1997
  • It is recognized that the dynamic of a structure is affected by the characteristics of the soil layer and foundation. However the design codes for the seismic design of structures are partially reflecting the caharcteristics of the soil layers due to the inherent complexity of them and the lack of systematic study results for the foundation-soil system, and leading to unconservative or too conservative results. In this study, the kinematic interaction effects of foundation-soil system was investigated for the seismic analyses of structures estimating the effects of the shear wave velocity, the depth of the soil layer, the embedment of a foundation and pile foundation, and the modified classification criteria of soil layers are proposed for the reasonable seismic analyses of structures considering the characteristics of soil layers and foundations. For the embedded medium or large foundations (including pile foundations), at least 60m soil layer below the foundation should be considered for the seismic analyses of structures to tate into account the kinematic interaction effects of the foundation-soil system, and also the rocking motion of foundation-soil system with or without piles should be included in the seismic analyses of structures.

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Parametric Study of Dynamic Soil-pile-structure Interaction in Dry Sand by 3D Numerical Model (3차원 수치 모델을 이용한 건조사질토 지반-말뚝-구조물 동적 상호작용의 매개변수 연구)

  • Kwon, Sun-Yong;Yoo, Min-Taek
    • Journal of the Korean Geotechnical Society
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    • v.32 no.9
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    • pp.51-62
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    • 2016
  • Parametric studies for various site conditions by using 3d numerical model were carried out in order to estimate dynamic behavior of soil-pile-structure system in dry soil deposits. Proposed model was analyzed in time domain using FLAC3D which is commercial finite difference code to properly simulate nonlinear response of soil under strong earthquake. Mohr-Coulomb criterion was adopted as soil constitutive model. Soil nonlinearity was considered by adopting the hysteretic damping model, and an interface model which can simulate separation and slip between soil and pile was adopted. Simplified continuum modeling was used as boundary condition to reduce analysis time. Also, initial shear modulus and yield depth were appropriately determined for accurate simulation of system's nonlinear behavior. Parametric study was performed by varying weight of superstructure, pile length, pile head fixity, soil relative density with proposed numerical model. From the results of parametric study, it is identified that inertial force induced by superstructure is dominant on dynamic behavior of soil-pile-structure system and effect of kinematic force induced by soil movement was relatively small. Difference in dynamic behavior according to the pile length and pile head fixity was also numerically investigated.

Application of Soil Factor on the Aseismic Design (내진 설계시 지반계수의 합리적 적용에 대한 연구)

  • 이인모;임종석
    • Geotechnical Engineering
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    • v.9 no.1
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    • pp.7-20
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    • 1993
  • The first Korean earthquake resistant design code was enacted in 1988. In the code, the soil factor which takes into account both the soil amplification factor and the soil -structare interaction effect is divided into three groups : soil factor, 5 : 1.0, 1.2 and 1.5. In order to assist in choosing the soil factors appropriately in the earthquake resistant design, the local site effects on the based shear force induced by earthquakes are considered in depth for typical soil conditions in Korea. The depth of the alluvial and/or weathered zone is usually not deep and the fresh rock is found at depth shallower than 20 meters, and even at about 10 meters around Seoul. One dimensional wave propagation theory and the elastic half space method are used to obtain the soil -structure interaction effect as well as the soil amplification effect. The kinematic interaction effect due to scattering of waves by pile foundation is also considered. Finally, the soil factor is recommended for each soil condition from loose state to dense, and also from shallow soil depth to deep, so that the designer can choose the factor with-out difficulty.

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Estimation of Kinematic Soil-Structure Interaction for Deeply Embedded Foundations (깊은 직접기초의 지반-구조물 상호작용 평가)

  • Kim Seng-Hyun
    • Journal of the Korean Geotechnical Society
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    • v.22 no.4
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    • pp.105-111
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    • 2006
  • Earthquake strong motion recordings from two deeply embedded sites with instrumented structures and free-field accelerographs are used to evaluate variations between foundation-level and free-field ground motions. The foundation free-field ground motion variations are quantified in terms of frequency-dependent transmissibility function amplitude, ${\mid}H\mid$. Comparisons are then performed with an analytical model for the assumed conditions of a rigid base slab and a vertically propagating, coherent incident wave. The limiting assumptions of the model are not strictly satisfactory for actual structures, and the results of the analysis reflect not only incoherence effects, but also possible foundation flexibility and wave inclination effects. Nonetheless, the simple analytical model is in an acceptable agreement with the empirical analysis and appears to be applicable in practice.