• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.104-408
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• 2003

케이블 장대 교량의 해석에 있어서 기하적인 비선형만을 고려한 해석이 보편적이었다. 하지만 이 연구에서는 내진 해석시 케이블지지 교량이 비탄성적으로 거동 할 수 있기 때문에, 기하적인 비선형 이외에 재료적인 비선형을 고려할 필요가 있음을 보이고자 한다. 극한 하중 상태를 모사하기 위하여 사하중에 하중계수를 곱하여 하중을 증가시켜 중력방향으로 하중을 가하였고, 지진에 대한 하중 상태를 모사하기 위하여 교축방향의 지진 하중에 대한 등가의 등분포 하중과 이의 0.3배에 해당하는 수직 방향 하중을 동시에 가하였다. 이러한 해석을 통하여 자중의 2배 이상의 하중이 가해지면 거더가 비탄성적으로 거동 할 수 있고, 또한 교축 방향과 수직 방향의 설계지진하중을 고려할 경우 수평방향의 구속이 모두 풀리면 주탑이 비탄성적으로 거동 할 수 있음을 알 수 있다. 따라서 케이블지지 교량의 지진 해석시 특정한 경우에 있어서는 비탄성 거동을 고려해야 할 필요가 있을 것으로 보인다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.1
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• pp.45-52
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• 2009

In this paper, a guideline for designing breakwater in wave loads and in seismic loads is proposed. A simple model structure in breaking wave zone is examined using Morison equation in consideration with the effect of an impact load, for evaluation of the wave loads. As the impact load effect is not significant, pressure distributions according to Goda are applied for evaluation of wave loads on breakwater. Structural behavior of breakwater in wave loads can be obtained using the Goda method, as well. For seismic analysis, Ofunato and Hachinohe models, as well as an artificial seismic acceleration loads model, are adopted. Soil-structure interaction analysis is carried out to find the seismic load effect. It is found that, in certain cases, structural deformation in wave loads is in the same level as deformation that in seismic loads. Thus, it is our recommendation that these two loads are considered at the same level in breakwater design.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1997.11a
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• pp.15-24
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• 1997

최근 우리나라에도 많은 지진사례가 보고되고 있으며, 이러한 지진하중은 원전설비 및 각종 기계설비등의 가동중 파손을 유발시킬 수 있는 잠재적 위험성이 높다. 이에 지진하중에 대한 안전성 확보의 필요성이 점차 대두되고 있다. 지진하중은 종ㆍ횡파에 의한 인장ㆍ압축이 반복되는 역사이클하중(reverse cyclic loading)형태로, 현재까지는 이를 고려한 설계개념이 미흡한 실정이며 이에 대한 파괴물성치의 확보는 물론 파괴물성치 평가 절차도 확립되어 있지 않은 상태이다. 따라서 지진하중에 대한 안전성확보를 위해서는, 역사이클 하중이 재료의 파괴특성 특히, 파괴저항(J-R)곡선에 미치는 영향이 고찰되어야 할 것이다. (중략)

• Land and Housing Review
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• v.3 no.4
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• pp.451-456
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• 2012

In this study, a numerical analysis to evaluate the reduction of seismic load due to pile group was performed and compared the peak ground acceleration(PGA) measured at free-field and foundation. The special attention was given to the amplification of seismic acceleration on the foundation due to the pile effects. The analysis considering pile effects was carried out for 4, 8 and 12 piles with same condition by PLAXIS 2D Dynamics. Based on the analysis results, it is found that the overall reduction in seismic load due to foundation and reduction rates are similar irrespective of pile numbers. This study gives a possibility for effective design of piled foundation by reducing seismic load about 20~25%.

• Computational Structural Engineering
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• v.4 no.4
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• pp.24-28
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• 1991

본 연구용역에서는 반도기계주식회사의 의뢰에 의거하여 Manbridge Crane의 지진하중에 대한 구조물의 안전성을 평가하였다. 구조해석은 유한요소 모형을 사용하여 사하중, 활하중 및 OBE(Operating Basis Earthquake)와 SSE(Safe Shut-down Earthquake)의 지진하중에 관한 해석을 수행하였다. Crane설치지점의 층응답스펙트럼을 입력으로 한 응답스펙트럼해법으로 지진해석을 수행하였다. Trolley의 위치와 정격하중의 유무에 따라서 5개의 구조모형을 작성하여 해석을 수행하였으며, 지진해석에는 35개의 자유진동모드가 고려되었다. 구조해석을 통하여 1) 구조부재의 과도응력 발생여부, 2) 보강재의 좌굴 가능성, 3) Hoist Rope의 안전성, 4) Crane의 전도의 가능성 및 Seismic Lug의 안전성, 5) 지진하중에 대한 제동력, 6) Crane의 주행 Rail로부터의 탈선여부, 7) Traversing Rail의 수직처짐, 8) 주행 Rail 및 End Stopper의 Anchor Bolt의 안정성, 9) Fuel Basket과 Handrail의 안전성을 검토하였다. 해석결과를 바탕으로 설계시방서에서 제시한 모든 설계요구조건을 만족시킬 수 있도록 수직 Frame의 보강부재를 보강하고, Hoist Rope 용량을 증가시키도록 제안하였다.

• Journal of Korean Society of Steel Construction
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• v.25 no.4
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• pp.399-407
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• 2013

Spatial structures have the different dynamic characteristics from general rahmen structures. Therefore, it is necessary to accurately analyze dynamic characteristics and seismic response for seismic design of spatial structure. Keel arch structure is used as an example structure because it has primary characteristics of spatial structures. In case of spatial structures with different ground condition and time lag, multiple support excitation may be subjected to supports of a keel arch structure. In this study, the response of the keel arch structure under multiple support excitation and with time lag are analyzed by means of the pseudo excitation method. Pseudo excitation method shows that the structural response is divided into two parts, ground displacement and structural dynamic response due to ground motion excitation. It is known that the seismic responses of spatial structure under multiple support excitation are different from those of spatial structure under simple excitation. And the seismic response of spatial structure with time lag are different from those of spatial structure without time lag. Therefore, it has to be necessary to analyze the seismic response of spatial structure under multiple support excitation and time lag because the spatial structure supports may be different and very long span. It is shown that the seismic response of spatial structure under multiple support seismic excitation are different from those of spatial structure under unique excitation.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.4
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• pp.11-22
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• 1998

An axisymmetric shell element which includes the effects of the meridional and circumferential cable prestresses is developed. It is coded for personal computer by the maximum use of axisymmetic properties and the dynamic analysis is performed under the seismic exitations. A ring element is used to fully utilize the characteristics of the axisymmetric shell. The eigenvalue solutions using 20 elements under the initial prestresses are in good agreement with the exact solutions. The results of the seismic analysis show that the radial deflection under the meridional prestress is a little larger than that under the circumferential prestress. The finite element model developed in this study can be very useful to the design applications.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.3 s.49
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• pp.65-75
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• 2006

Nonlinear pushover analysis is used to evaluate the earthquake response of building structures. To accurately predict the inelastic response of a structure, the prescribed story load profile should be able to describe the earthquake force profile which actually occurs during the time-history response of the structure. In the present study, a new modal combination method was developed to predict the earthquake load profiles of building structures. In the proposed method, multiple story load profiles are predicted by combining the modal spectrum responses multiplied by the modal combination factors. Parametric studies were performed far moment-resisting frames and walls. Based on the results. the modal combination factors were determined according to the hierarchy of each mode affecting the dynamic responses of structures. The proposed modal combination method was applied to prototype buildings with and without vertical irregularity. The results showed that the proposed method predicts the actual story load profiles which occur during the time-history responses of the structures.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6A
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• pp.955-963
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• 2006

As the geometrical characteristic of the curved bridge, the seismic response of curved bridges are different from straight bridges. This study analyzed the seismic response of the curved bridges considering diverse factors such as radius of curvature, direction of seismic load and support condition. The improved simple modeling of the curved bridge for seismic analysis is proposed, and it is compared with the detail modeling in order to verify the simple modeling. Three simply supported curved bridges and six 3-span continuous bridges are selected for seismic analysis. The behavior of curved bridges are evaluated in terms of the displacement and the force at supports and piers under seismic load applied in various directions. The results of this study show that upward reaction force may appear in simply supported curved bridge under seismic load. And continuous curved bridges are affected by the direction of the seismic load.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1997.04a
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• pp.136-143
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• 1997

본 연구에서는 철골구조물을 대상으로 지진격리(Base-Isolation)를 사용하였을 때의 진동감소 효과를 분석하기 위하여 지진하중에 대한 진동대 실험을 수행하였다. 실험 대상구조물은 $\frac{1}{4}$축소모형의 3층 철골구조물이며, 입력지진은 여러 계측기록과 UBC 설계스펙트럼으로부터 3가지 지반조건에 대하여 작성한 인공지진기록을 사용하였다. 축소 실험모형은 기초가 고정된 일반적인 철골구조물과 적층고무받침(Laminated Rubber Bearing) 형식의 지진격리장치(Base Isolator)를 사용한 구조물을 동시에 설치하여 그 지진응답을 비교 관찰하였다. 대부분의 하중하에서 지진격리장치가 사용된 철골구조물의 경우에 지진응답이 현저히 감소하는 것을 알 수 있으나, 장주기파의 성분이 강한 지반운동에 대해서는 오히려 지진응답이 증가하였다. 그러나 여러 지반조건에 대하여 UBC 시방서에서 규정한 설계하중에 대하여는 진동감소효과가 우수함을 보인다.