• 콘크리트학회지
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• 제23권4호
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• pp.33-39
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• 2011

• Earthquakes and Structures
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• 제5권6호
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• pp.753-779
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• 2013

One of the most important issues in progressive collapse mechanism of the buildings is evaluation of the collapse distribution in presence of the earthquake loads. Here, collapse propagation is investigated by tracking down the location and type of the collapsed beam and column elements, from the first element to the entire buildings. 6-story reinforced concrete ordinary moment resisting frame buildings with one directional mass eccentricity of 0%, 5%, 15% and 25% are studied to investigate differences among the progressive collapse mechanism of the regular and irregular buildings. According to the results of the nonlinear time history analyses, there are some patterns to predict progressive collapse scenarios in beam and column elements of the similar regular and irregular buildings. Results also show that collapse distribution patterns are approximately independent of the earthquake records.

• 한국건설관리학회논문집
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• 제22권3호
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• pp.31-39
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• 2021

모듈러 공법은 내장재와 기계·전기 설비 등이 시공된 구조체를 제작 공장에서 건설 현장으로 운반하여 설치 및 시공하는 공법이다. 모듈러 공법은 특히 주택과 같은 소규모의 비교적 구조가 간단한 건축물을 대상으로 활발하게 적용되고 있는 추세이다. 국내건설 산업에 모듈러 주택의 도입된 기간이 길지 않은 만큼 아직 모듈러 주택의 환경적 특성에 대한 연구가 부족한 실정이다. 따라서 본 연구의 목적은 모듈러 주택의 단열성능을 적외선 이미지 분석과, Air-Surface Thermal Ratio 방법, 실내외 온도차비를 활용하여 실증적으로 분석하는 것이다. 이를 위해 실제 서울시에 위치한 준공 후 2년이 경과된 모듈러 주택과 RC 주택을 비교하여 단열성능 분석하였다.

• Structural Engineering and Mechanics
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• 제86권4호
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• pp.547-571
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• 2023

To deeply probe the actual earthquake level and fragility of typical reinforced concrete (RC) structures under multiple intensity grades, considering diachronic measurement building stock samples and actual observations of representative catastrophic earth shocks in China from 1990 to 2010, RC structures were divided into traditional RC structures (TRCs) and bottom reinforced concrete frame seismic wall masonry (BFM) structures, and the empirical damage characteristics and mechanisms were analysed. A great deal of statistics and induction were developed on the historical experience investigation data of 59 typical catastrophic earthquakes in 9 provinces of China. The database and fragility matrix prediction model were established with TRCs of 4,122.5284×104 m² and 5,844 buildings and BFMs of 5,872 buildings as empirical seismic damage samples. By employing the methods of structural damage probability and statistics, nonlinear prediction of seismic vulnerability, and numerical and applied functional analysis, the comparison matrix of actual fragility probability prediction of TRC and BFM in multiple intensity regions under the latest version of China's macrointensity standard was established. A novel nonlinear regression prediction model of seismic vulnerability was proposed, and prediction models considering the seismic damage ratio and transcendental probability parameters were constructed. The time-varying vulnerability comparative model of the sample database was developed according to the different periods of multiple earthquakes. The new calculation method of the average fragility prediction index (AFPI) matrix parameter model has been proposed to predict the seismic fragility of an areal RC structure.

• 한국전산구조공학회논문집
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• 제35권4호
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• pp.235-242
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• 2022

시공 중인 건물은 시공이 완료된 건물과는 다르게 콘크리트의 강도발현이 충분히 이루어지지 않았기 때문에 지진과 같은 자연재해에 더 취약한 모습을 가질 수 있다. 현재 국내 기준은 건축물의 내진등급별 최소성능 목표를 제시하고 있지만, 설계를 위한 지진하중은 재현주기 2,400년의 지진위험도를 기반으로 한다. 하지만 건물의 시공기간은 건물의 사용기간보다 훨씬 짧기 때문에 재현주기 2,400년의 지진을 시공 중인 건물에 적용하는 것은 과도하다. 따라서 이 연구는 주거용으로 사용되는 철근콘크리트 건물의 시공 중 지진하중을 분석하기 위해 5층, 15층, 25층, 60층 건물의 시공단계모델을 작성하고 재현주기에 따라 저감한 지진하중을 적용하여 구조적 안정성을 확인하였다. 그 결과, 시공기간에 따라 선정한 재현주기의 지진을 적용할 때 구조적 안정성을 확인하였으며, 건물의 규모의 따라 구조적 안전성을 확보할 수 있는 지진재현주기를 확인하였다.

• 한국공간구조학회논문집
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• 제22권2호
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• pp.29-37
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• 2022

The collapse of reinforced concrete (RC) frame buildings is mainly caused by the failure of columns. To prevent brittle failure of RC column, numerous studies have been conducted on the seismic performance of strengthened RC columns. Concrete jacketing method, which is one of the retrofitting method of RC members, can enhance strength and stiffness of original RC column with enlarged section and provide uniformly distributed lateral load capacity throughout the structure. The experimental studies have been conducted by many researchers to analyze seismic performance of seismic strengthened RC column. However, structures which have plan and vertical irregularities shows torsional behavior, and therefore it causes large deformation on RC column when subjected to seismic load. Thus, test results from concentric cyclic loading can be overestimated comparing to eccentric cyclic test results, In this paper, two kinds of eccentric loading pattern was suggested to analyze structural performance of RC columns, which are strengthened by concrete jacketing method with new details in jacketed section. Based on the results, it is concluded that specimens strengthened with new concrete jacketing method increased 830% of maximum load, 150% of maximum displacement and changed the failure modes of non-strengthened RC columns.

• 국제초고층학회논문집
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• 제6권3호
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• pp.285-296
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• 2017

It's been a decade since post-tension system began to be applied in earnest to buildings in Korea. In the meantime, post-tension system has been used in various buildings as main structural system including tall buildings. And post-tension system plays a role to overcome architectural limit of regular RC tall buildings particularly in the realization of long span with shallower depth than other structural system. The post-tensioned building market of Korea has been steadily grown in recent years with such advantage. Recently, post-tension technology is adapted for special structural members like belt walls. In this paper, the authors would like to explain design and construction of tall buildings in Korea using post-tension technology.

• Earthquakes and Structures
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• 제5권1호
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• pp.1-22
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• 2013

Soft storey failure mechanism is a common collapse mode for masonry-infilled (MI) reinforced concrete (RC) buildings subjected to severe earthquakes. Simple analytical equations correlating global with local ductility demands are derived from pushover (PO) analyses for seismic assessments of regular MI RC frames, considering the critical interstorey drift ratio, number of storeys and lateral loading configurations. The reliability of the equations is investigated using incremental dynamic analyses for MI RC frames of up to 7 storeys. Using the analytical ductility relationship and a coefficient-based method (CBM), the response spectral accelerations and period shift factors of low-rise MI RC frames are computed. The results are verified through published shake table test results. In general applications, the analytical ductility relationships thus derived can be used to bypass the onerous PO analysis while accurately predicting the local ductility demands for seismic assessment of regular MI RC frames.

• Computers and Concrete
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• 제31권4호
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• pp.337-348
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• 2023

Shear wall is commonly used as a lateral force resisting system of concrete mid-rise and high-rise buildings, but it brings challenges in providing relatively large space throughout the building height. For this reason, the structure system where the upper structure with bearing, non-bearing and/or shear walls that sits on top of a transfer plate system supported by widely spaced columns at the lower stories is preferred in some regions, particularly in low to moderate seismic regions in Asia. A thick reinforced concrete (RC) plate has often been used as a transfer system, along with RC transfer girders; however, the RC plate becomes very thick for tall buildings. Applying the post-tensioning (PT) technique to RC plates can effectively reduce the thickness and reinforcement as an economical design method. Currently, a simplified model is used for numerical modeling of PT transfer plate, which does not consider the interaction of the plate and the upper structure. To observe the actual behavior of PT transfer plate under seismic loads, it is necessary to model whole parts of the structure and tendons to precisely include the interaction and the secondary effect of PT tendons in the results. This research evaluated the seismic behavior of shear wall-type residential buildings with PT transfer plates for the condition that PT tendons are included or excluded in the modeling. Three-dimensional finite element models were developed, which includes prestressing tendon elements, and response spectrum analyses were carried out to evaluate seismic forces. Two buildings with flat-shape and L-shape plans were considered, and design forces of shear walls and transfer columns for a system with and without PT tendons were compared. The results showed that, in some cases, excluding PT tendons from the model leads to an unrealistic estimation of the demands for shear walls sit on transfer plate and transfer columns due to excluding the secondary effect of PT tendons. Based on the results, generally, the secondary effect reduces shear force demand and axial-flexural demands of transfer columns but increases the shear force demand of shear walls. The results of this study suggested that, in addition to the effect of PT on the resistance of transfer plate, it is necessary to include PT tendons in the modeling to consider its effect on force demand.

• 콘크리트학회논문집
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• 제26권5호
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• pp.599-606
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• 2014

초고층 건물의 연쇄붕괴는 큰 피해를 발생시키므로 초고층 건물의 설계 단계에서 반드시 고려해야할 사항이다. 유한요소법을 이용한 초고층 건물의 연쇄붕괴 해석은 해석 시간이 지나치게 많이 소요되어 사실상 불가능하다고 할 수 있다. 본 논문에서는 유한 요소법의 대안으로 응용 요소법을 이용한 연쇄붕괴 해석의 유용성을 살펴보았다. 초고층 건물의 연쇄붕괴 해석을 위하여 규모 축소 모델링 방안을 제안하였다. 제안한 규모 축소 모델링 방안은 폭파하중의 직접적인 피해를 받는 부분만 해석모델에 포함하고 제외되는 나머지 부분의 질량과 전달하중 그리고 강성은 하나의 층에 집중시키는 방법이다. 20층 고층 철근콘크리트 건물에 대한 전체 모델과 축소된 모델을 세 가지 연쇄붕괴 시나리오에 대하여 연쇄붕괴 해석을 수행하고 그 결과를 비교하였다. 축소 모델은 전체 모델과 유사한 연쇄붕괴 양상을 보여 주지만 소요된 시간은 전체 모델의 약30%로 줄일 수 있었다. 본 논문에서 제안된 연쇄붕괴 해석 방안은 비정상 하중에 의한 초고층 건물의 연쇄붕괴 해석에 유용하게 사용될 수 있다.