• 농업과학연구
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• 제41권4호
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• pp.455-460
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• 2014

In this study, structural behavior of plastic greenhouse foundation was investigated using rational finite element modeling for structures which have different material properties each other. Because the concrete foundation of plastic greenhouse and soil which surround and support the concrete foundation have very different material property, the boundary between two structures were modeled by a interface element. The interface element was able to represent sliding, separation, uplift and re-bonding of the boundary between concrete foundation and soil. The results of static and dynamic analysis showed that horizontal and vertical displacement of concrete foundation displayed a decreasing tendency with increasing depth of foundation. The second frequency from modal analysis of structure including foundation and soil was estimate to closely related with wind load.

• 한국해안·해양공학회논문집
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• 제23권1호
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• pp.18-25
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• 2011

본 연구에서는 진동기반 자기회귀모델을 이용하여 항만케이슨의 지반-구조 경계부 손상모니터링을 수행하였다. 이를 위해, 첫째, 케이슨 구조물의 지반-구조 경계부 손상모니터링을 위한 기법으로써 진동기반 자기회귀모델을 선정하였다. 둘째, 케이슨의 유한요소해석을 통하여 지반-구조 경계부 모니터링을 위한 진동기반 자기회귀모델 기법을 수치적으로 검증하였다. 마지막으로, 모형케이슨의 진동실험을 통해 진동기반 자기회귀모델 기법의 케이슨 지반-구조 경계부 손상 모니터링의 적용성을 검증하였다.

• Interaction and multiscale mechanics
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• 제4권1호
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• pp.65-83
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• 2011

In this study, two extreme cases of compatibility of the horizontal displacements between the foundation and soil are considered, for which the pressure and settlements of the isolated footings and member end actions in structural elements are obtained using the three dimensional models and numerical experiments. The first case considered is complete slip between foundation and soil, termed as the un-coupled analysis. In the second case of analysis, termed as the coupled analysis, complete welding is assumed of joints between the foundation and soil elements. The model and the corresponding computer program developed simulate these two extreme states of compatibility giving insight into the variation of horizontal displacements and horizontal stresses and their intricacies, for evaluation of the influence of using the interface elements in soil-structure interaction analysis of three dimensional multiscale structures supported by isolated footings.

• 한국해양공학회지
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• 제26권1호
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• pp.34-40
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• 2012

This paper presents an experimental modal analysis of a caisson-type breakwater to produce basic information for the structural health assessment of a caisson structure. To achieve the objective, the following approaches are implemented. First, modal analysis methods are selected to examine the modal characteristics of a caisson structure. Second, experimental modal analyses are performed using finite element analyses and lab-scale model tests. Third, damage scenarios that include several damage levels in a foundation-structure interface are designed. Finally, the effects of damage on the modal characteristics are analyzed for the purpose of utilizing them for damage identification.

• 한국전산구조공학회논문집
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• 제15권1호
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• pp.9-20
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• 2002

본 연구의 목적은 비선형 흙-구조물 상호 작용문제를 연구하기 위한 계산 절차를 개발하는 것이다. 흙-구조물 상호 작용 거동을 연구하기 위하여 연직과 수평하중을 동시에 받은 대상기초와 강널말뚝으로 보강된 기초지반에 대한 유한 요소 수치해석을 하였으며 흙과 기초구조물 사이의 상호작용 거동을 모델하기 위하여 접합요소를 사용하였다 주 해석 결과는 다음과 같다. 1. 침하와 측방변위의 예측에 대해서는, 접합요소를 사용한 결과가 더 큰 값을 얻었다. 2. 극한지지력 결정에 대해서는 접합요소를 사용한 경우가 약 12%정도 더 작게 나타났다 3. 대상기초의 수평과 연직변위는 접합요소의 영향을 받았다.

• Smart Structures and Systems
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• 제10권6호
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• pp.517-546
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• 2012

In this paper, vibration-based methods to monitor damage in foundation-structure interface of harbor caisson structure are presented. The following approaches are implemented to achieve the objective. Firstly, vibration-based damage monitoring methods utilizing a variety of vibration features are selected for harbor caisson structure. Autoregressive (AR) model for time-series analysis and power spectral density (PSD) for frequency-domain analysis are selected to detect the change in the caisson structure. Also, the changes in modal parameters such as natural frequency and mode shape are examined for damage monitoring in the structure. Secondly, the feasibility of damage monitoring methods is experimentally examined on an un-submerged lab-scaled mono-caisson. Finally, numerical analysis of un-submerged mono-caisson, submerged mono-caisson and un-submerged interlocked multiple-caissons are carried out to examine the effect of boundary-dependent parameters on the damage monitoring of harbor caisson structures.

• Earthquakes and Structures
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• 제14권1호
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• pp.85-94
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• 2018

The paper focuses on the seismic responses of a hyperbolic cooling tower resting on soil foundation represented by the three-parameter Vlasov elastic soil model. The three-parameter soil model eliminates the necessity of field testing to determine soil parameters such as reaction modulus and shear parameter. These parameters are calculated using an iterative procedure depending on the soil surface vertical deformation profile in the model. The soil and tower system are modeled in SAP2000 structural analysis program using a computing tool coded in MATLAB. The tool provides a two-way data transfer between SAP2000 and MATLAB with the help of Open Application Programming Interface (OAPI) feature of SAP2000. The response spectrum analyses of the tower system with circular V-shaped supporting columns and annular raft foundation on elastic soil are conducted thanks to the coded tool. The shell and column forces and displacements are presented for different soil conditions and fixed raft base condition to investigate the effects of soil-structure interaction. Numerical results indicate that the flexibility of soil foundation leads to an increase in displacements but a decrease in shell membrane and column forces. Therefore, it can be stated that the consideration of soil-structure interaction in the seismic response analysis of the cooling tower system provides an economical design process.

• Earthquakes and Structures
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• 제12권2호
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• pp.153-163
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• 2017

The underlying goal of the present paper is to investigate soil and structural uncertainties on impedance functions and structural response of soil-shallow foundation-structure (SSFS) system using Monte Carlo simulations. The impedance functions of a rigid massless circular foundation resting on the surface of a random soil layer underlain by a homogeneous half-space are obtained using 1-D wave propagation in cones with reflection and refraction occurring at the layer-basement interface and free surface. Firstly, two distribution functions (lognormal and gamma) were used to generate random numbers of soil parameters (layer's thickness and shear wave velocity) for both horizontal and rocking modes of vibration with coefficients of variation ranging between 5 and 20%, for each distribution and each parameter. Secondly, the influence of uncertainties of soil parameters (layer's thickness, and shear wave velocity), as well as structural parameters (height of the superstructure, and radius of the foundation) on the response of the coupled system using lognormal distribution was investigated. This study illustrated that uncertainties on soil and structure properties, especially shear wave velocity and thickness of the layer, height of the structure and the foundation radius significantly affect the impedance functions, and in same time the response of the coupled system.

• Geomechanics and Engineering
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• 제4권3호
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• pp.173-190
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• 2012

With recent growing interests in the Performance-Based Seismic Design and Assessment Methodology, more realistic modeling of a structural system is deemed essential in analyzing, designing, and evaluating both newly constructed and existing buildings under seismic events. Consequently, a shallow foundation element becomes an essential constituent in the implementation of this seismic design and assessment methodology. In this paper, a contact interface fiber section element is presented for use in modeling soil-shallow foundation systems. The assumption of a rigid footing on a Winkler-based soil rests simply on the Euler-Bernoulli's hypothesis on sectional kinematics. Fiber section discretization is employed to represent the contact interface sectional response. The hyperbolic function provides an adequate means of representing the stress-deformation behavior of each soil fiber. The element is simple but efficient in representing salient features of the soil-shallow foundation system (sliding, settling, and rocking). Two experimental results from centrifuge-scale and full-scale cyclic loading tests on shallow foundations are used to illustrate the model characteristics and verify the accuracy of the model. Based on this comprehensive model validation, it is observed that the model performs quite satisfactorily. It resembles reasonably well the experimental results in terms of moment, shear, settlement, and rotation demands. The hysteretic behavior of moment-rotation responses and the rotation-settlement feature are also captured well by the model.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.856-861
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• 2010

In recent days, the safety of the levee has been an issue because the levee has become bigger according to the Four-river Restoration Project and so on. The greater part of the levee damage has occurred in the interface between soils and the structures. Specially, the drainage construction crosses the levee keeps its settlement down in order to secure a grade of drainage. However, when the settlement isn't generated by using foundation such as pile, the levee is more likely to have leakage at the interface because the construction doesn't behave with soils. In our study, therefor, testing of the behavior of the levee having the drainage construction was carried out to clarify the effects of the foundation type of drainage construction.