• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.646-655
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• 2002

장대 교량이 위치한 지반에서 지진에 의한 지반 운동은 교량의 길이 방향으로 공간적인 변화를 일으킨다. 지형 변화나 지반 매질의 물성 변화가 있는 비균질한 지반에서 지반 운동의 진폭과 주파수 성분은 변화하고 이 부지 효과(site effect)는 교량의 지진 응답에 지배적인 영향을 미치며 그 영향은 파전파 효과(wave passage effect)에 의한 지반 각 지점의 지진파 도달시간 차이나 비균질성이 큰 지반에서 파의 다중 반사, 굴절에 의한 영향보다 크다[1]. (중략)

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.4 s.44
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• pp.11-18
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• 2005

Inelastic seismic analysis is necessary for the seismic design due to the nonlinear behavior of a structure-soil system, and the importance of the performance based design considering the soil-structure interaction is recognized for the reasonable seismic design. In this study, elastic and inelastic seismic response analyses of a single degree of freedom system on the soft soil layer were peformed considering the nonlinearity of the soil for the 11 weak or moderate, and 5 strong earthquakes scaled to the nominal peak acceleration of 0.075g, 0.15g, 0.2g and 0.3g. Seismic response analyses for the structure-soil system were peformed in one step applying the earthquake motions to the bedrock In the frequency domain, using a pseudo 3-D dynamic analysis software. Study results indicate that it is necessary to consider the nonlinear soil-structure interaction effects and to perform the performance based seismic design for the various soil layers rather than to follow the routine procedures specified in the seismic design codes. Nonlinearity of the soft soil excited with the weak earthquakes also affected significantly to the elastic and inelastic responses due to the nonlinear soil amplification of the earthquake motions, and it was pronounced especially for the elastic ones.

• Proceedings of the Korean Geotechical Society Conference
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• 2007.09a
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• pp.345-345
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• 2007

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.333-338
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• 1996

강진에 의한 원전구조물의 동적해석시 지반의 비선형특성은 반드시 고려해야 할 사항이다. 지반의 비선형특성은 지반-구조계의 동적응답을 구하는 과정에서 가장 중요한 요소중의 하나며 이를 고려한 비선형 지진해석은 일반적으로 매우 복잡하고 정해를 구하기가 매우 어려운 문제다. 본 연구에서는 비선형 해법으로 널리 사용되고 있는 등가선형화방법을 사용하여 계측결과가 있는 TEPSCO 비선형 지진문제를 해석하였으며 이 방법의 정확도와 적용성을 분석하였다. 아울러 축대칭기법을 사용하여 비선형지진해석을 수행할때의 문제점에 관해서도 검토하였다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.4
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• pp.243-254
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• 2021

In this study, the conservatism of the response displacement method (RDM) for the seismic response analysis of box-shaped power cable tunnels was evaluated. A total of 50 examples were used considering the cross-sections of 25 power cable tunnels and two soil conditions for each power cable tunnel. The following three methods were applied for the analysis by the RDM: (1) single cosine method, (2) double cosine method, and (3) dynamic free-field analysis method. A refined dynamic analysis method considering soil-structure interaction (SSI) was employed to compare the conservatism of the RDM. The double cosine method demonstrated the most conservative result, while the dynamic free-field analysis method yielded the least deviation. The soil stiffness reduction factor, C, for the double cosine method was recommended to be 0.9 and 0.7 for the operational performance and collapse prevention levels, respectively, to ensure a probability of at least 80% that the member force by the RDM is larger than that of dynamic SSI analysis.

• Journal of the Korean Geotechnical Society
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• v.17 no.5
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• pp.97-105
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• 2001

현장타설말뚝의 건전도 평가에서 충격반향, 충격응답기법과 같은 비검측공 시험법을 적용하는 사례가 점차로 증가되는 추세에 있다. 비검측공시험법의 적용성을 체계적으로 평가하기 위해 수행된 일련의 연구결과 중에서 본 논문에서는 시험법의 결함탐지 능력을 평가하기 위해 수행된 해석적 연구결과에 관해 논한다. 이 연구에서는 시험법의 결함탐지능력에 대한 제반 영향인자 중에서 결함의 유형, 위치 및 크기의 영향을 평가하고자 하였다. 이를 위해서 여러 가지 조건에서 말뚝머리에 작용하는 충격하중에 대한 흙-말뚝 구조의 동적응답을 ABAQUS를 이용한 유한요소법으로 해석하였다. 이로부터 얻은 신호를 충격반향 혹은 충격응답기법으로 처리.분석하여 각 시험법의 결함탐지 능력을 평가해 보았다. 연구결과 이들 두 기법 모두 결함의 위치와 유형은 비교적 정확하게 탐지하는 것으로 나타났다. 그러나 충격응답기법을 이용하여 추정한 결함 크기는 신뢰도가 매우 낮았다. 이 문제를 해소하여 시험법의 적용성을 향상시키기 위해서는 측정된 동적응답신호를 이용하여 적절한 역계산 기법을 개발하여 적용할 필요가 있다는 결론을 얻었다.

• Journal of the Earthquake Engineering Society of Korea
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• v.16 no.3
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• pp.1-12
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• 2012

In this study, an analysis method for the earthquake response of an offshore wind turbine model is developed, considering the effects of the fluid-structure-soil interaction. The turbine is modeled as a tower with a lumped mass at the top of it. The tower is idealized as a tubular cantilever founded on flexible seabed. Substructure and Rayleigh-Ritz methods are used to derive the governing equation of a coupled structure-fluid-soil system incorporating interactions between the tower and sea water and between the foundation and the flexible seabed. The sea water is assumed to be a compressible but non-viscous ideal fluid. The impedance functions of a rigid footing in water-saturated soil strata are obtained from the Thin-Layer Method (TLM) and combined with the superstructure model. The developed method is applied to the earthquake response analysis of an offshore wind turbine model. The method is verified by comparing the results with reference solutions. The effects of several factors, such as the flexibility of the tower, the depth of the sea water, and the stiffness of the soil, are examined and discussed. The relative significance of the fluid-structure interaction over the soil-structure interaction is evaluated and vice versa.

• Tunnel and Underground Space
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• v.20 no.4
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• pp.292-298
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• 2010

The purpose of this study is to evaluate an effect of ground vibration caused by blasting on the concrete brick structure. For the purpose, dynamic response time-history of the structure assumed single degree of freedom (SDOF) system and vibration time-history directly measured from the structure were examined, using Newmark $\beta$ method based on data measured at ground. The time-history was interpreted from the measured data of ground and structure in single hole blasting. Vibration magnitude between ground vibration and structure in single hole blasting and 20 ms interval blasting was about three times and was shown larger vibration on the structure. By time-history analysis of structure dynamic response, the value was almost the same one with the data measured from the structure. It indicates that the vibration characteristics of structures may be predicted on the basis of the ground vibration data measured from the sub-ground of structure.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.2 s.42
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• pp.47-58
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• 2005

Dynamic response analysis in time dimain is conducted for floating bridges with discrete pontoons subject to spatial variation of ground motions. The Spatial variation of ground motions is considered with the coherency function model which represents wave passage, incoherence and local site effects. The superstructure of the bridge is represented by space frame and elastic catenary cable elements, the abutment us modelde with the spring element of FHWA guideline for considering soil structure interaction and the concept of retardation function is utilized to consider the frequency dependency of the hydrodynamic coefficients which are obtainde by boundary element method. multiple support excitations considering the spatial variation. The noticeable amplification of the response can be shown when the spatial variation of ground motions is incorporated in the anallysis of floating bridges.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.429-432
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• 2009

본 논문에서는 현수교에 대하여 지반-구조물 상호작용을 고려한 해석을 수행하였다. 교량의 앵커리지와 기초를 부분구조법(Structure method)을 이용한 지반-구조물 상호작용(Soil-Structure Interaction) 해석프로그램 SASSI를 이용하여 구조물 저면에서의 지반 임피던스(Impedance)를 계산하고 이로부터 앵커리지 및 기초와 지반에 대응하는 강성, 질량, 그리고 감쇠를 가지는 집중 파라메터 모델을 구하였다. 그리고 현수교 유한요소 모델에 앵커리지 및 기초와 지반에 대한 집중 파라메터 모델을 연계하여 전체 교량에 대한 지반-구조물 시스템을 구성하고 시간영역에서의 지반 운동에 대한 동적해석을 수행하였다. 해석결과를 지반-구조물 상호작용을 고려하지 않은 경우와 고려한 경우를 비교하였고 파동전달효과를 고려한 경우와 고려하지 않은 경우를 비교함으로써 지반-구조물 상호작용의 영향을 살펴보았다.