• 한국안전학회지
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• 제32권4호
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• pp.66-72
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• 2017

Recently, the use of high-strength concrete is increasing due to the trend of constructing high-rise and long span structures. The benefit of using the high-strength concrete is that it increases the durability and strength while it reduces the cross-sectional area of the bridge deck slabs. Moreover, it offers more safety as these bridge deck slabs applying high-strength requires strict structural performance verification. In this study, the fatigue performance of the bridge deck slabs applying 80 MPa high-strength concrete was verified through various experiments. The experimental results showed that the specimens satisfy the conditions of flexural strength, punching shear strength, deflection and cracking. In conclusion, the bridge deck slabs designed by 80 MPa high-strength concrete are enough safe despite of its low thickness.

• 한국건축시공학회지
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• 제16권3호
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• pp.279-288
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• 2016

The fundamental performance of any construction material should cover at least two phases: safety and serviceability. Safety commonly represents adequate strength, while serviceability encompasses the control of cracking and deflections at service loads. With respect to rapid hydraulic binders as a construction material, the above two phases should also be considered. Recent research on rapid cooling ladle furnace slag (RC-LFS) has drawn much attention, particularly given that it shows remarkable rapid hydraulic ability to pulverize to a fineness of $6,300cm^2/g$. This industrial byproduct could contribute to developing the sustainability of the rapidly hardening cementitious material system. This paper aims to expand upon the applicability of an RC-LFS-based binder that is composed of two parts. It also seeks to illustrate the engineering performance of an RC-LFS-based hybrid fiber-reinforced composite and to increase the strength of the RC-LFS-based composite. Each step of this experiment followed ASTM standards. The engineering performance, in both fresh state and hardening state, was tested and discussed in this paper. According to the experimental results for fresh concrete, the air content increased following the addition of polypropylene fiber. For hardened concrete, the toughness and strength improved following the addition of a hybrid fiber. The hybrid fiber mixture, which contains 0.75% of steel fiber and 0.25% of polypropylene fiber, shows even better engineering performance than other mixtures.

• 화약ㆍ발파
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• 제20권3호
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• pp.83-96
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• 2002

Reconstruction and redevelopment of old and dilapidated apartment and housing have been increasing to provide more housing accommodation and to secure the safety of building structures since the middle of 1990's. Since, however, little researches on the demolition technique have been made, conventional mechanical demolition method were applied to the most of works that resulted in flooding in small demolition companies. Problems associated with mechanical demolition method are increase not only in working days and costs, but also in public claims, particularly for high-rise building structures. This is to contribute the demolition industries bt providing the concept, standards, and technique of demolition engineering while maximizing working efficiency and minimizing public claims.

• 한국지진공학회논문집
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• 제13권5호
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• pp.41-50
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• 2009

지진피해를 입은 건물의 주된 관심사는 건물에 남아 있는 내진성능 및 여진에 대한 안전성을 판단하는데 있다. 따라서 지진피해를 입은 지역 사회의 조속한 복귀를 위해서는 건물의 잔존내진성능 평가방법을 확립해 두는 것이 필수적이다. 본 연구에서는 무보강 조적채움벽체를 갖는 RC 건물의 잔존내진성능 평가방법 개발을 주목적으로, 전형적인 학교건물을 대상으로 축력레벨을 변수로 한 실스케일, 단층 1스팬 실험체를 제작하여 정적 반복가력실험을 실시하였다. 실험 중 잔존내진성능을 판정하는데 유용한 정보 중 하나인 잔류균열폭을 상세히 측정하였다. 본 논문에서는 잔류균열폭과 잔존내진성능과의 관계에 대해서 실험적, 해석적으로 검토하고 잔존내 진성능 평가를 위한 각 손상도 레벨에 대응하는 내진성능 저감계수를 제안한다.

• 한국건축시공학회지
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• 제10권6호
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• pp.127-135
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• 2010

물류시설은 층고가 높고 구조가 단순하며, 투자회수를 위한 조속한 운영이 필요하기 때문에 공기단축이 절실한 특징이 있다. 이에 따라 인력 및 원가절감, 공기단축을 기대할 수 있는 PC공법의 사용은 RC조에 비해 경쟁력을 확보할 수 있다. 그러나 국내의 시공사들은 RC공법에 익숙해져 있어, PC공법에 대한 부정적 인식이 팽배하며, 새로운 공법적용에 대한 노력이 미흡한 문제점이 있다. 본 연구의 사례현장은 단위기둥의 높이가 14m로 동일한 규격의 장주(長柱)가 110본 소요되는 현장으로 RC공법을 이용할 경우 시공성, 경제성, 공사기간, 안전성등의 문제발생이 예상된다. 따라서 본 연구는 RC조로 계획된 물류창고 현장을 PC공법으로 시공하여 인력 및 원가절감, 공기단축효과를 비교분석하고, 개선효과를 제시하는데 목적을 두고 있다. 향후 본 연구의 결과물은 물류시설 시공 시공기단축, 품질 및 시공성 향상, 안전성향상, 원가절감효과를 가져올 신공법개발 연구의 기초자료로 사용될 것으로 사료된다.

• 한국안전학회지
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• 제25권3호
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• pp.100-106
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• 2010

Most of the school buildings were built before the seismic code was established. To consider the sunlight and ventilation to the partition walls are built about 1m height beside columns at typical school buildings. For the reason, columns which is consisted school building occur brittle failure shape by the reduced effective depth. In this study, experimental test for retrofitting effect by Aramid Fiber Reinforced Polymers(AFRP) strips on masonry infilled reinforced concrete(RC) frames is performed. The test results were to ensured enough time to evacuate due to the enhancement of ductility and strength of school buildings to withstand earthquakes using AFRP strips.

• Structural Engineering and Mechanics
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• 제51권3호
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• pp.447-470
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• 2014

Numerical simulation of the non-linear behavior of (RC) structural walls subjected to severe earthquake ground motions requires a reliable modeling approach that includes important material characteristics and behavioral response features. The objective of this paper is to optimize a simplified method for the assessment of the seismic response and damage development analyses of an RC structural wall building using macro-element model. The first stage of this study investigates effectiveness and ability of the macro-element model in predicting the flexural nonlinear response of the specimen based on previous experimental test results conducted in UCLA. The sensitivity of the predicted wall responses to changes in model parameters is also assessed. The macro-element model is next used to examine the dynamic behavior of the structural wall building-all the way from elastic behavior to global instability, by applying an approximate Incremental Dynamic Analysis (IDA), based on Uncoupled Modal Response History Analysis (UMRHA), setting up nonlinear single degree of freedom systems. Finally, the identification of the global stiffness decrease as a function of a damage variable is carried out by means of this simplified methodology. Responses are compared at various locations on the structural wall by conducting static and dynamic pushover analyses for accurate estimation of seismic performance of the structure using macro-element model. Results obtained with the numerical model for rectangular wall cross sections compare favorably with experimental responses for flexural capacity, stiffness, and deformability. Overall, the model is qualified for safety assessment and design of earthquake resistant structures with structural walls.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2007년도 추계 학술논문 발표대회
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• pp.83-86
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• 2007

This study provides the practical application of the concrete using fiber to protect from fire studied by previous research. The fluidity and air content is satisfied with the targets, and the compressive strength is over 60MPa on W/B 35% and 80MPa on W/B 20 and 25%. For the properties of the spalling after the fire test, there is no spalling or slight occurrence on the specimens. However, for the RC column, the covering concrete fall off caused by spalling occurrence. Based on the results, it is thought that the fiber content should be put into the safety factor to prevent spalling for the structures.

• 국제초고층학회논문집
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• 제9권4호
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• pp.315-323
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• 2020

In June 2016, the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) in Japan delivered countermeasures against long-period ground motions caused by strong earthquakes along the Nankai trough. However, the countermeasures do not cover high-rise buildings equal to or shorter than 60 m in height, which do not require earthquake response analyses in the seismic design. Hence, in the present study, earthquake response analyses for such high-rise reinforced concrete (RC) buildings were performed under artificial ground motions assumed in the OS1 and OS2 regions to determine the base shear coefficients that satisfy a given safety demand. Furthermore, the results from the earthquake response analyses were estimated by the authors' proposed method based on the equivalent linearization method, showing good agreement and inspiring suggestions for more accurate and simplified estimations.

• 한국전산구조공학회논문집
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• 제28권1호
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• pp.19-27
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• 2015

근래 국내 초고층 주상복합 건물에는 철근콘크리트구조가 보편적으로 적용되는데, 이러한 철근콘크리트 초고층 주상복합 건물은 시공 시점에 따라 구조적인 문제가 발생할 수 있다. 따라서, 시공 중인 철근콘크리트 초고층 주상복합 건물에 대하여, 시공 시점별 구조 안전성 및 횡력저항성능을 검토하고자 한다. 이를 위해, 예제 모델로 탑상형의 초고층 주상복합 60층 건물을 선정했고, 기존의 범용구조해석 프로그램을 사용하여 구조해석을 수행하였다. 각 시공 시점별 10층, 20층, 30층, 40층, 50층, 60층 완료모델과 60층 완공단계 모델의 구조성능을 비교하였다. 구조성능 비교를 위해 이 모델들의 고유치해석을 수행하였으며, 횡력저항성능과 부재별 단면성능을 검토하였다. 횡력저항성능 검토를 위해 횡변위비와 층간변위비를 검토했고, 부재별 단면성능 검토는 완공단계에 대한 설계강도비와 시공단계의 설계강도비를 비교하여 부재안전성을 검토하였다. 이 연구를 통해, 시공 중인 철근콘크리트 초고층 건물의 구조 안전성을 검토하고 시공단계에 적합한 구조해석 및 설계하중의 가이드라인을 제시하고자 한다.