• Computational Structural Engineering
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• v.2 no.3
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• pp.85-95
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• 1989

This paper presents a study of soil-structure interaction problems using infinite elements. The infinite elements are formulated for homogeneous and layered soil media, based on approximate expressions for three components of propagating waves, namely the Rayleigh, compressive and shear waves. The integration scheme which was proposed for problems with single wave component by waves. The integration scheme which was proposed for problems with single wave component by Zenkiewicz is expanded to the multi-waves problem. Verifications are carried out on rigid circular footings which are placed on and embedded in elastic half space. Numerical analysis is performed for a containment structure of a nuclear power plant subjected to a horizontal seismic excitation.

• Geotechnical Engineering
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• v.7 no.3
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• pp.5-20
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• 1991

동하중을 받는 진동기계기초의 동적해석을 수행하기 위해서는 지반의 임피던스함수의 적절한 산 출이 필수적이며, 회전기계 -기초 -지반의 상호작용이 고려된 동적해석이 요구된다. 이제까지 지 반의 임퍼던스함수는 주로 원형기초에 한하여 제시되어 왔으나, 기초의 형상은 실제로 지반의 임퍼 던스함수에 중요한 역할을 한다. 그러므로 본 연구에서는 여러가지 형상 및 매립된 기초에 적용할 수 있는 임퍼던스함수를 제시하였다. 그리고, 제시된 임퍼던스함수를 바탕으로, 회전기계 -기초- 지반의 상호작용이 고려된 동적해석을 수행할 수 있는 프로그램을 개발하였으며, 개발된 프로그램 을 이용하여 예제해석을 통하여 각종 임피던스함수의 적용에 따른 기계기초의 응답을 비교 검토하였다. 본 연구의 주된 결론은 다음과 같이 요약할 수 있다. 1) 주파수독립 임퍼던스함수와 주파수종속 임피던스함수를 이용한 결과를 비교해 볼 때,수평방 향과 회전방향에 대해서는 동적응답이 커다란 차이를 보이지 않으나, 연직방향 운동에 대해서는 상 당한 차이를 보인다. 2) 표면기초와 매립기초를 비교해 본 결과, 매립기초에 있어서 수평방향과 회전방향에 있어서는 동적응답이 거의 일정한 간에 도달하므로 기초가 어느 정도 매립된다면 안전측에 들어간다고 볼 수 있다. 그러나, 연직방향에 있어서는 매립여부에 따라 상당한 차이를 보인다.

• Journal of the Korean GEO-environmental Society
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• v.20 no.10
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• pp.39-46
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• 2019

The interaction between the ground and structures should be considered for seismic design of group piles supporting the superstructure. The p-y curve has been used widely for the analysis of nonlinear relationship between the ground and structures, and various researches have conducted to apply the dynamic p-y curve for seismic design of group piles. This curve considers the interaction between the ground and structures under the dynamic load such as an earthquake. However the supported effect by the pile cap and the interaction by inertia behavior of superstructures. Therefore, the shaking table test was conducted to verify the effect of the change of the pile cap in group piles supporting superstructures embedded in sandy soil. The test condition is that the arrangement and distance between centers of piles are fixed and the length of the pile cap is changed for various distances between the pile cap side and the pile center. The result shows that the distance between the pile cap side and the pile center have an effect on the dynamic p-y curve and the effect of group piles.

• Journal of the Korean GEO-environmental Society
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• v.19 no.10
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• pp.35-41
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• 2018

Dynamic interaction of the ground-foundation-structure must be considered for safety of earthquake resistant design for piles supported structures. The p-y curve, which is proposed in the static load and cyclic load cases, is used for the earthquake resistant design of piles. The p-y curve does not consider dynamic interaction of the ground-foundation-structure on dynamic load cases such as earthquake. Therefore, it is difficult to apply the p-y curve to earthquake resistant design. The dynamic p-y curve by considering dynamic interaction of the ground-foundation-structure has been studied, and researches had same conditions that pile caps were on the ground surface and superstructures were added on pile caps for the simple weight. However, group piles are normally embedded into the ground except for marine structures, so it seems that the embedding the pile cap influences on the dynamic p-y curve of group piles. In this study, the shaking table model test was conducted to confirm dynamic behavior of group piles by the embedded pile cap in the ground. The result showed that dynamic behavior was different between two cases by embedding the pile cap or not.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.1
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• pp.39-50
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• 2007

This paper presents 3D infinite elements for the elastodynamic problem with multi-layered half-space. Five different types of infinite elements are formulated by using approximate expressions of multiple wave components for the wave function in multi-layered soil media. They are horizontal, horizontal-corner, vortical, vertical-corner and vertical-horizontal-comer infinite elements. The elements can effectively be used for simulating wane radiation problems with multiple wave components. Numerical example analyses are presented for rigid disk, square footings and embedded footing on homogeneous and layered half-space. The numerical results show the effectiveness of the proposed infinite elements.

• Journal of the Earthquake Engineering Society of Korea
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• v.1 no.1
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• pp.41-49
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• 1997

This paper presents the result of an international cooperative research on the post-correlation analysis of forced vibration tests and the prediction of earthquake responses of a large-scale seismic test structure. The dynamic analysis is carried out using the axisymmetric finite element method incorporating in finite elements for the for field soil region. Through the post-correlation analysis, the properties of the soil layers are revised so that the best correlation in the responses may be obtained compared with the measured force vibration test data. Utilizing the revised soil properties as the initial linear values, the seismic responses are predicted for an earthquake using the equivalent linearlization technique. It has been found that the predicted responses by the equivalent nonlinear procedure are in excellent agreement with the observed responses, while those using the linear properties are fairly off from the measured results.

• Geotechnical Engineering
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• v.6 no.2
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• pp.5-20
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• 1990

In the seismic analysis of structures, where the dynamic soil-structure interaction (DSSI) is considred, earthquake input motions as well as dynamic soil properties are random in nature. To take into account the random nature of both the input motions and the dynamic soil properties systematically, a probabilistic analysis of the DSSI subjected to seismic loading is proposed in this paper, The complex response method formulized by the elastic half space theory, the random vibration theory, and the Rosenblueth's two-point estimate method are combined for the proposed probabilistic analysis. The conclusions drawn from this study are as follows ' 1) The uncertainty bands of the earthquake input motions proposed by Kanai-Tajimi as well as those of the dynamic properties are large the coefecients of variation of those parameters tinge from 0.4 to 0.6. 2) The uncertainties of the dynamic soil properties are more sensitive to the structural responses than those of the input motion parameters. 3) The effect of correlations between the input motion parameters and the dynamic soil properties is negligible.

• Journal of the Korean Institute of Gas
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• v.5 no.3 s.15
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• pp.51-54
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• 2001

지진 등과 같은 외부 진동하중에 의해 발생되는 구조물의 진동은 구조물의 독립적 거동뿐만 아니라 지반과 구조물 기초의 접촉면을 통해 상호 영향을 미치게 된다. 특히 LNG 저장탱크나 원자력발전소 등과 같이 대현 상부구조물의 경우 상호작용력은 크게 작용하게 된다. 본 연구에서는 상부 구조계의 단순화된 형태인 기초계의 동적거동을 파악하기 위해 주파수영역 경계요소법을 사용하여 수치적으로 연구하였다. 반무한체 상에 존재하는 무질량 강체 표면기초에 대해 반무한 기본해를 이용하여 동적거동이 고찰되었으며 기존의 해석결과와 비교, 검토하여 본 연구방법의 타당함을 입증하였다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.1 no.1
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• pp.87-92
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• 1989

In this study, the nonlinear dynamic model of the systems which include the offshore structure, the surrounding sea water in terms of the added mass, the foundation in terms of frequency independent springs, dashpots, and the floating ice feature with its hydrodynamic added mass, are proposed for the problem of the large ice floes impact. Dynamic Analysis is performed on two site conditions, sand site and silt site, and on two seasons, winter and summer, for various ice floe velocities. As a result of study, Ice floes from energy balenced method is lower than that from dynamic modeling on sand site, and higher than the on silt site.

• Journal of the Korean Society for Railway
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• v.7 no.4
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• pp.32-36
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• 2004