• Earthquakes and Structures
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• 제13권6호
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• pp.539-549
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• 2017

Existing reinforced concrete frame buildings designed for vertical loads could only suffer severe damage during earthquakes. In recent years, many research activities were undertaken to develop a reliable and practical analysis procedure to identify the safety level of existing structures. The Incremental Dynamic Analysis (IDA) is considered to be one of the most accurate methods to estimate the seismic demand and capacity of structures. However, the executions of many nonlinear response history analyses (NL_RHA) are required to describe the entire range of structural response. The research discussed in this paper deals with the proposal of an efficient Incremental Modal Pushover Analysis (IMPA) to obtain capacity curves by replacing the nonlinear response history analysis of the IDA procedure with Modal Pushover Analysis (MPA). Firstly, In this work, the MPA is examined and extended to three-dimensional asymmetric structures and then it is incorporated into the proposed procedure (IMPA) to estimate the structure's seismic response and capacity for given seismic actions. This new procedure, which accounts for higher mode effects, does not require the execution of complex NL-RHA, but only a series of nonlinear static analysis. Finally, the extended MPA and IMPA were applied to an existing irregular framed building.

• 한국전산구조공학회논문집
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• 제24권6호
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• pp.685-690
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• 2011

본 논문은 자동요소생성 시스템을 이용한 화학적펌프의 지진해석에 대한 내용이다. 전처리시스템을 CAD시스템, 유한요소 코드와 통합시킨 자동화된 해석시스템은 구조물 최적화 디자인에 효과적으로 사용되어 진다. 해석조건이 수반된 유한요소모델은 자동적으로 해석모델로 부터 생성되어 진다. 또한, 유한요소모델은 해석코드에 의해 자동적으로 해석되어 진다. 이 통합화된 유한요소 시뮬레이션 시스템의 효용성을 화학펌프와 같은 3차원 복잡구조물에 적용하여 보았다.

• 한국공간구조학회논문집
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• 제22권1호
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• pp.33-40
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• 2022

When the center of stiffness and the center of mass of the structure differ under the seismic load, torsion is caused by eccentricity. In this study, an analysis model was modeled in which the positions of the core and the plane rotation axis of a 60-story torsional atypical structure with a plane rotation angle of 1 degree per floor were different. The structural behavior of the analysis model was analyzed, and the earthquake response behavior of the structure was analyzed based on the time history analysis results. As a result, as the eccentricity of the structure increased, the eccentricity response was amplified in the high-rise part, and the bending and torsional behavior responses were complex in the low-order vibration mode. As a result of the analysis, the maximum displacement and story drift ratio increased due to the torsional behavior. The maximum story shear force and the story absolute maximum acceleration showed similarities for each analysis model according to the shape of the vibration mode of the analysis model.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1994년도 가을 학술발표회 논문집
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• pp.183-190
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• 1994

The paper provides a review of the analysis methods currently being used to perform seismic analysis of free standing high density spent fuel storage racks for PWR. On the basis of the analysis techniques obtained by KAERI from the design experience of Yonggwang unit 3&4 and Ulchin unit 3&4, the analysis procedure and modeling methods are discussed. The analysis of free standing fuel racks requires consideration of complex phenomena such as hydrodynamic coupling, impact through gap between fuel assembly and poison box and racks, frictional effect, rigid body sliding and tipping and etc. The present modeling of these factors is reviewed in comparison with the recommendation of regulatory group. Further improvement of analysis method and the current issues for the development are discussed.

• Structural Engineering and Mechanics
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• 제28권1호
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• pp.89-105
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• 2008

The paper presents a study on the effects of soil-structure-interaction (SSI) on the performance of the compliant liquid column damper (CLCD) for the seismic vibration control of short period structures. The frequency-domain formulation for the input-output relation of a flexible-base structure with CLCD has been derived. The superstructure has been modeled as a linear, single degreeof-freedom (SDOF) system. The foundation has been considered to be attached to the underlying soil medium through linear springs and viscous dashpots, the properties of which have been represented by complex valued impedance functions. By using a standard equivalent linearization technique, the nonlinear orifice damping of the CLCD has been replaced by equivalent linear viscous damping. A numerical stochastic study has been carried out to study the functioning of the CLCD for varying degrees of SSI. Comparison of the damper performance when it is tuned to the fixed-base structural frequency and when tuned to the flexible-base structural frequency has been made. The effects of SSI on the optimal value of the orifice damping coefficient of the damper has also been studied. A more convenient approach for designing the damper while considering SSI, by using an established model of a replacement oscillator for the structure-soil system has also been presented. Finally, a simulation study, using a recorded accelerogram, has been carried out on the CLCD performance for the flexible-base structure.

• 한국방재학회 논문집
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• 제5권3호
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• pp.11-21
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• 2005

곡선교량의 복잡한 동적거동을 이해하고, 내진해석시 합리적인 해석방법을 선정할 수 있는 기초적인 연구를 수행하기 위하여 ??자유도를 포함한 절점당 7자유도를 갖는 곡선보요소와 직선보요소를 갖는 동적유한 요소해석 프로그램을 사용하여 곡선교량의 내진해석을 수행하였다. 자유진동해석 결과로부터 곡선교량의 모드특성을 직선교량과 비교하여 분석하였다. 또한, 동일지간장을 갖는 직선교와 곡선교의 지진시 거동특성을 분석하고, AASHTO의 정규교량으로 분류된 곡선교량의 내진해석방법에 대해 비교하였다. 또한, 지진하중작용방향과 곡선교량의 내부중심각을 변화시켜 곡선교량의 동적거동을 파악하였다.

• 한국지반공학회지:지반
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• 제6권2호
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• pp.5-20
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• 1990

지반-구조물의 동적 상호작용 해석에 있어서, 흙의 특성치들 뿐만 아니라 입력지진 자체도 무척 Random하다. 본 논문에서는 이 Randomness를 고려하기 위하여 확률론적 방법을 적용하여 상호작용 해석에 미치는 영향을 연구하였다. 이 확률론적 적용을 위해 Elastic Half Space 이론에 의해 얻어진 Complex Response 방법, Random Vibration Theory와 Rosenblueth의 Two Point Estimate 방법을 사용하여 해석을 수행하여 다음과 같은 결론을 얻었다. 1) 흙의 동적 특성치 뿐만 아니라 Kanai-Tajimi에 의하여 제안된 입력지진의 PSD Function 의 불확정성도 상당히 큼을 알 수 있었다. 이때의 Parameter의 변동계수는 0.4에서 0.6의 범위를 갖는다. 2) 흙의 동적 특성치의 불확정성의 영향이 입력지진의 그것보다는 구조물에 미치는 영향이 큼 을 알 수 있었다. 3) 입력지진과 흙의 동적 특성치 사이의 상관계수에 의한 영향은 무척 작음을 알 수 있었다.

• 한국강구조학회 논문집
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• 제18권4호
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• pp.481-490
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• 2006

지진의 피해를 입은 후 건물의 실제 성능은 많은 요인에 영향을 받는다. 신축 구조물이나 기존 구조물의 지진 성능 예측은 복잡하다. 그 이유는 고려되어져야 하는 많은 요소와 지진 반응의 복잡성뿐만 아니라 이러한 예측과 관련된 타고난 불확실성 과 가변성 때문이다. 본 연구의 목적은 구조물의 능력 평가와 반응 요구에서의 불확실성과 가변성의 적절한 취급과 결합이다. 일관된 방법으로 demand와 capacity에서의 불확실성과 가변성을 설명하기 위하여 신뢰성 이론에 기초한 성능평가의 접근 방법이 초고층 철골 건축물의 내진성능평가 법으로 채택되어져 오고 있다. 신뢰성 이론에 근거한 내진성능평가에 대한 기본 체계와 통계적 연구에 대한 핵심 요소를 요약하였다. dema nd 요소와 capacity 요소의 통계적인 분석을 위하여 국내 기준에 맞는 전형적인 초고층 철골 건축물을 36개 설계하였다. global drift capacity 산정을 위해 철골 모멘트 골조 건물을 증분동해석 하였다.

• Earthquakes and Structures
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• 제26권2호
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• pp.149-162
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• 2024

Aiming at the current research on the dynamic response analysis of the vehicle-bridge system under earthquake, which fails to comprehensively consider the impact of seismic wave incidence angles, terrain effects and soil-structure dynamic interaction on the bridge structure, this paper proposes a multi-point excitation input method that can consider the oblique incidence seismic P Waves based on the viscous-spring artificial boundary theory, and verifies the accuracy and feasibility of the input method. An overall numerical model of vehicle-bridge-soil foundation system in valley terrain during oblique incidence of seismic P-wave is established, and the effects of seismic wave incidence characteristics, terrain effects, soil-structure dynamic interactions, and vehicle speeds on the dynamic response of the bridge are analyzed. The research results indicate that with an increase in P wave incident angle, the vertical dynamic response of the bridge structure decreased while the horizontal dynamic response increased significantly. Traditional design methods which neglect multi-point excitation would lead to an unsafe structure. The dynamic response of the bridge structure significantly increases at the ridge while weakening at the valley. The dynamic response of bridge structures under earthquake action does not always increase with increasing train speed, but reaches a maximum value at a certain speed. Ignoring soil-structure dynamic interaction would reduce the vertical dynamic response of the bridge piers. The research results can provide a theoretical basis for the seismic design of vehicle-bridge systems in complex mountainous terrain under earthquake excitation.

• Structural Engineering and Mechanics
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• 제48권1호
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• pp.57-75
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• 2013

It is still inadequate for investigating the highly nonlinear and complex mechanical behaviors of single-layer latticed domes by only performing a force-based demand-capacity analysis. The energy-based balance method has been largely accepted for assessing the seismic performance of a structure in recent years. The various factors, such as span-to-rise ratio, joint rigidity and damping model, have a remarkable effect on the load-carrying capacity of a single-layer latticed dome. Therefore, it is necessary to determine the maximum load-carrying capacity of a dome under extreme loading conditions. In this paper, a mechanical model for members of the semi-rigidly jointed single-layer latticed domes, which combines fiber section model with semi-rigid connections, is proposed. The static load-carrying capacity and seismic performance on the single-layer latticed domes are evaluated by means of the mechanical model. In these analyses, different geometric parameters, joint rigidities and roof loads are discussed. The buckling behaviors of members and damage distribution of the structure are presented in detail. The sensitivity of dynamic demand parameters of the structures subjected to strong earthquakes to the damping is analyzed. The results are helpful to have a better understanding of the seismic performance of the single-layer latticed domes.