• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2000
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• pp.108-115
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• 2000

Numerical analysis of slop stability is presented using seismic displacement, response seismic coefficient, and earthquake response analysis methods. In seismic displacement and response seismic coefficient methods, horizontal static seismic force is considered as 0.2g while vertical static seismic force is not considered in analysis. For earthquake response analysis Hahinoha-wave is applied, It is found from result that analysis using response seismic coefficient method is much more conservative than that using seismic displacement method Also, analysis result using earthquake response analysis method is somewhat less conservative about 25% when compared with that using seismic displacement method.

• 한국지반공학회논문집
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• 제19권4호
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• pp.211-221
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• 2003

지중구조물의 내진해석에 자주 이용되는 방법으로 응답변위법이 있다. 응답변위법은 정적인 해석방법으로, 이 방법의 핵심은 지진시 지중구조물 측벽에 작용하는 지반변위를 산정하는 것이다. 이때 해석대상부지의 고유주기에 해당하는 기반면의 속도 응답스펙트럼 값을 결정하는 일이 매우 중요하다. 본 연구에서는 국내 설계지반운동기준에 적합한 기반면의 속도 응답스펙트럼 산정과 지반응답해석 없이 응답변위를 신뢰성있게 산정하는 간편법에 대한 연구를 수행하였다. 해석결과 국내 내진설계 기준의 S$_A$ 지반의 지표면 가속도 응답스펙트럼을 적분하여 속도 응답스펙트럼으로 환산하는 방법과 지반을 두 개의 층으로 구분하여 지진시 지반의 응답변위를 산정하는 방법을 현업 설계에 적용할 경우 경제적으로 큰 잇점이 있을 것으로 판단된다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 춘계 학술발표회논문집
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• pp.129-139
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• 2003

The response displacement method is the most frequently used method for seismic design of buried structures. This method is pseudo-static method, and the evaluations of velocity response spectrum of seismic base and response displacement of surrounding soil are the most important steps. In this study, the evaluation of velocity response spectrum of seismic base according to the Korean seismic design guide and the simple method of calculating the response displacement were studied. It was found that velocity response spectrum of seismic base can be estimated by direct integrating the ground-surface acceleration response spectrum of soil type $S_{A}$, and the evaluation of the response displacement using double cosine method assuming two layers of soil profile shows the advantages in the seismic design.n.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1012-1017
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• 2008

In this study, We examine closely the capacity spectrum method which a kind of displacement-based method evaluated by displacement of structure as an alternative to the load-based analysis method. The displacement-based method can easily review the strength of structure, seismic performance, ductility. Seismic performance by using capacity spectrum method is divided into design response spectrum and capacity spectrum. We can diagram design response spectrum by deciding the design seismic factor depending on performance target, site classification, seismic level, return period as UBC-97. Capacity spectrum is a load-displacement curve obtained by Push-over analysis considering the geometric parameter and the material parameter. We execute the seismic performance evaluation by using the capacity spectrum method to reinforced concrete pier which has been seismic design. As a result, We confirmed that there is a yield point and a ultimate point close by design response spectrum of UBC-97.

• 한국지진공학회논문집
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• 제26권1호
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• pp.31-38
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• 2022

Based on the nonlinear static analysis and the approximate seismic evaluation method adopted in "Guidelines for seismic performance evaluation for existing buildings, two methods to calculate strength demand for retrofitting individual structural walls in unreinforced masonry buildings are proposed." The displacement coefficient method to determine displacement demand from nonlinear static analysis results is used for the inverse calculation of overall strength demand required to reduce the displacement demand to a target value meeting the performance objective of the unreinforced masonry building to retrofit. A preliminary seismic evaluation method to screen out vulnerable buildings, of which detailed evaluation is necessary, is utilized to calculate overall strength demand without structural analysis based on the difference between the seismic demand and capacity. A system modification factor is introduced to the preliminary seismic evaluation method to reduce the strength demand considering inelastic deformation. The overall strength demand is distributed to the structural walls to retrofit based on the wall stiffness, including the remaining walls or otherwise. Four detached residential houses are modeled and analyzed using the nonlinear static and preliminary evaluation procedures to examine the proposed method.

• 한국지진공학회논문집
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• 제21권1호
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• pp.69-76
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• 2017

Seismic analyses of a pile under a large rigid basement foundation embedded in the homogeneous soil layer were performed practically by a response displacement method assuming a sinusoidal wave form. However, it is hard to take into account the characteristics of a large mat foundation and a heterogeneous soil layer with the response displacement method. The response displacement method is relevant to the 2D problems for longitudinal structures such as tunnel, underground cave structure, etc., but might not be relevant with isolated foundations for building structures. In this study, seismic pile analysis by a pseudo 3D finite element method was carried out to compare numerical results with results of the response displacement method considering 3D characteristics of a foundation-soil system which is important for the building foundation analyses. Study results show that seismic analyses results of a response displacement method are similar to those of a pseudo 3D numerical method for stiff and dense soil layers, but they are too conservative for a soft soil layer inducing large soil pressures on the foundation wall and large pile displacements due to ignored foundation rigidity and resistance.

• Structural Engineering and Mechanics
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• 제58권2호
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• pp.379-395
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• 2016

A seismic strengthening method using Velcro is proposed to improve the seismic performance of columns in RC frame structures. The proposed method was evaluated experimentally using three fabricated RC specimens. Velcro was wrapped around the columns of the RC-frame specimen to prevent concrete spall falling. The reinforcing performance of the Velcro was determined from comparison of results on seismic performance (i.e., strength, displacement, failure mode, displacement ductility capacity and amount of dissipated energy). As the displacement of the reinforced specimens was increased, the amount of dissipated energy increased drastically, and the displacement-ductility-capacity of the reinforced specimens also increased. The final failure mode of RC frame structure was changed. As a result, it was concluded that the proposed seismic strengthening method using Velcro could be used to increase the displacement ductility of RC columns, and could be used to change the final failure mode of RC-frame structures.

• 한국지진공학회논문집
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• 제9권3호
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• pp.23-32
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• 2005

편심이 있는 구조물이 지진하중을 받는 경우 비틀림의 발생으로 특정부재에 응력 및 변위가 집중되고 이는 전혀 예상치 못한 구조물의 파괴를 유발할 수 있다. 본 연구에서는 각 횡저항 부재의 한계 변위를 기반으로 하여 구조물 전체의 횡변위와 비틀림각의 관계도(D-R Relationship: Displacement-Rotation Relationship)를 작성하고 변위스펙트럼을 이용하여 내진성능평가를 수행하는 방법을 제안한다. 제안된 내진성능평가의 방법은 시간이력해석의 결과를 이용해서 검증하였다. 또한 다양한 지진수준에 대해 구조물의 다른 성능수준을 기준으로 하는 다단계 내진성능평가를 수행하였다. 최종적으로 그 결과를 기준으로 D-R 관계도를 이용한 내진보강 전략을 제시하였다. 내진보강은 각 부재의 강도/강성을 증가시키는 방법과 연성도를 증가시키는 두 가지의 방법을 사용하였다. 특히 강도/강성을 증가시키는 내진보강 전략에서는 보강의 최적화를 위하여 보강전략을 최적화 문제로 구성하고 BFGS Quasi-Newton method를 이용하여 최적보강전략을 수립하는 과정을 제시하였다.

• 산업기술연구
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• 제26권B호
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• pp.119-126
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• 2006

Capacity spectrum method(CSM) of ATC-40(1996) and displacement coefficient method(DCM)of FEMA-273(1997) are applied to evaluate the seismic performance of bridges. In this study, equivalent response is obtained from nonlinear static analysis for the 3spans continues bridge and nonlinear maximum displacement response is calculated using CSM and DCM. Nonlinear maximum displacement response of DCM is larger than this of CSM. It is method that DCM can evaluate target displacement and ductility of structural to be easy and simple, but tend to overestimate the maximum displacement response. Therefore, this method is mainly used at preparation design level to evaluate the structural response. It is not desirable to evaluate the seismic performance using DCM.

• 한국지진공학회논문집
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• 제7권5호
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• pp.67-73
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• 2003

현 도로교의 내진해석은 구조물이 하중 이상의 강도를 갖도록 하는 하중기반해석법에 근거하고 있다. 본 연구에서는 이러한 하중기반해석의 대안책으로 구조물의 성능평가 대상을 변위로 하는 변위기반해석의 일종인 역량스펙트럼법을 제시하였다. 하중기반해석에서 내진설계가 수행되어진 기존 철근콘크리트 교각에 대하여 역량스펙트럼법에 의한 내진성능을 평가하였다. 그 결과, 역량스펙트럼법은 간편하고 신속하게 구조물의 비탄성 응답을 현실적으로 평가할 수 있었으며 비탄성 응답을 일으키는 다양한 지반운동 수준에 대해 구조물에 발생하는 변위를 평가할 수 있었고, 기존 구조물의 내진성능에 대한 평가나 신설구조물의 성능목표에 대한 설계검증에 효율적으로 적용 가능하였다.