http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
용접 띠철근 보강된 콘크리트 기둥의 역학적 거동에 관한 실험적 연구
최창식,Choi, Chang-Sik,Saatcioglu, Murat 한국콘크리트학회 1999 콘크리트학회지 Vol.11 No.2
지진다발 지역에서는 철근콘크리트 기둥의 단면을 합리적으로 구속함과 동시에 횡보강 띠철근의 세심한 배근등이 요구된다. 이러한 요구조건을 만족시키기 위한 보편적인 횡보강근 사용의 문제점으로는 높은 체적비(high volumetric ratio), 조밀한 간격(close spacings), 겹침(overlapping of hoops), 구부림(bends), 구부림 연장 (bend extensions), 시공상의 어려움과 콘크리트 타설상의 문제 등이다. 이러한 문제점을 해결하기 위한 한 방법으로는 요구되는 횡보강근의 체적비, 배역, 크기 등에 따라 이를 기조립, 용접하여 사용하는 것이다. 용접된 횡보강근의 사용은 겹침과 구부림, 구부림의 연장 등이 필요하지 않기 때문에 조립이 간편하고, 축방향 철근의 지지에 적합한 치수의 정확성과 재료를 절감시킬 수 있다. 더우기, 단면 내 횡보강 철근의 간격이 조밀해짐으로써, 코아 콘크리트 주변의 구속력을 균등히 분배시키게 되고, 이에 따라 코아 콘크리트의 거동을 향상시키는 결과를 얻을 수가 있다. 이에 본 연구에서는 이러한 용접 띠철근으로 보강된 철근콘크리트 기둥의 역학적 거동을 실험적으로 규명함과 동시에 철근콘크리트 기둥의 내진성능 향상을 위한 기초자료를 제공하고자 하였다. 그 결과 횡보강근의 강도와 연성에 영향을 미치지 않도록 용접됨과 동시에 충분한 신률을 가진다면, 용접된 격자형 횡보강근은 기둥의 띠철근으로써 사용가능한 것으로 판단된다. 특히, 용접된 격자형 횡보강근이 유효하게 거동하기 위하여는 1) 용접된 접합부위의 강도가 보강근의 모재강도 이상 2) 신률이 4% 이상이어야 할 필요가 있다. An experimental investigation was conducted to study the structural behavior of concrete columns confined with welded grids. The full-scale columns with different volumetric ratio, spacing and arrangement of welded reinforcement grids were tested under simulated seismic loading. The columns were subjected to constant axial compression of approximately 20% or 40% of their capacities accompanied by incrementally increasing lateral deformation reversals. The results indicate that the welded reinforcement grid can be used effectively as confinement reinforcement provided that the steel used, have sufficient ductility and the welding process employed does not alter the strength and elongation characteristics of steel. The grids improved the structural performance of columns, which developed lateral drift ratios in excess of 3% with the spacing and volumetric ratio of transverse reinforcement similar to those required by the ACI 318-95 Building Code. Drift capacity further increased when grids with larger number of cells were used. Furthermore, the use of grids reduced congesting of reinforcement while the dimensional accuracy provided perfect support to longitudinal reinforcement.
LBL-SA법을 이용한 고굴절률 ZrO<sub>2</sub> 박막 제조
최창식,이지선,이미재,이영진,전대우,안병조,김진호,Choi, Chang-Sik,Lee, Ji-Sun,Lee, Mi-Jai,Lee, Young-Jin,Jeon, Dae-Woo,Ahn, Byoung-Jo,Kim, Jin-Ho 한국전기전자재료학회 2017 전기전자재료학회논문지 Vol.30 No.4
$ZrO_2/PSS$ thin film with a high refractive index was fabricated on a glass substrate by a layer-by-layer self-assembly method. The surface morphology and thickness of the fabricated $ZrO_2/PSS$ thin films were measured as a function of the number of $(ZrO_2/PSS)n$. As the number of $(ZrO_2/PSS)n$ increased from n = 5 to n = 20, RMS roughness decreased from 29.01 nm to 8.368 nm. The $ZrO_2$ thin films exhibited high transmittance of 85% or more; and the 15-bilayer thin film exhibited the highest transmittance among the samples. The transmittance of the fabricated $(ZrO_2/PSS)_{15}$ thin film was ca. 90.8% in the visible range. The refractive index of the glass substrate coated by a $(ZrO_2/PSS)_{15}$ thin film with a thickness of 160 nm increased from ca. 1.52 to 1.74 at the 632 nm wavelength.
Screen Printing법을 이용한 반사방지막 제조
최창식,남정식,이지선,전대우,이영진,배현,김진호,Choi, Chang-Sik,Nam, Jeong-Sic,Lee, Ji-Sun,Jeon, Dae-Woo,Lee, Young-jin,Bae, Hyun,Kim, Jin-Ho 한국재료학회 2018 한국재료학회지 Vol.28 No.12
Anti-reflection thin films are fabricated on glass substrates using the screen printing method. Tetra ethyl silicate(TEOS) and methyl tri methoxy silane(MTMS) are used as starting materials and buthyl carbitol acetate(BCA) and buthyl cellusolve(BC) are mixed to improve the viscosity of the solution. Anti-reflection thin films are fabricated according to the number of the screen mesh and the characteristics improve as the mesh size increases. The transmittance and reflectance of the coated thin film using 325 mesh are about 94 % and 0.43 % in the visible wavelength. The thickness and refractive index of the AR thin film are 107 nm and n = 1.26, respectively.
겹침이음실험을 통한 삼중나노소재 혼입 철근콘크리트보의 부착성능에 대한 실험적 고찰
유진규(Jin-Gue Ryu),손동희(Dong-Hee Son),배백일(Baek-Il Bae),유창기(Chang-Gi Yoo),최창식(Chang-Sik Choi) 대한건축학회 2023 대한건축학회논문집 Vol.39 No.10
This study aims to assess the impact of combining triple hybrid reinforced concrete with carbon nanotubes, nanosilica, and graphene oxide on bond strength. The mechanical properties of these materials were evaluated through material testing and assessed bond strength via lap-splice experiments. The material testing revealed that nano-reinforced concrete had a slight increase in compressive strength compared to regular concrete but showed a significant improvement in splitting tensile strength. It also exhibited decreased volumetric strain and Poissons ratio. To understand if these mechanical properties influenced bond strength, laboratory splice experiments were conducted using eight reinforced concrete specimens, varying splice length and cover thickness. The results of the lap-splice experiment showed variations in bond strength depending on the inclusion of nanomaterials in the mixture, with varying increases in bond strength as splice strength changed. This suggests that the combination of these triple nanomaterials does impact the bond performance of concrete.
아파트 구조물의 구조안전성 및 진동특성 평가에 관한 사례 연구
최창식 ( Choi Chang-sik ),이리형 ( Lee Li-hyung ) 한국구조물진단유지관리공학회 1998 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.2 No.1
A problem of frequency in the field of low-frequencies such as high-rise apartment building or construction vibration are often found. In this study, damage reason of a 25 stories apartment building was searched on the basis of actual damage. To find the damage reason, structural analysis and design procedure were reviewed. And also, non-destructive and low-frequency vibration test on that damaged apartment building was performed. The results indicate that the main damage reason is not by the low-frequency vibration but the asymmetrical plan of that building.
친환경 건축물의 실현을 위한 PC구조 시스템의 연구 동향
최창식 ( Choi Chang-sik ),김은주 ( Kim Eun-joo ),이혜연 ( Lee Hye-yeon ) 한국구조물진단유지관리공학회 2005 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.9 No.2
As environmental problem assumed serious aspect, a develope of techniques for the environmental load decrease is required in all the fields. Also construction, the improvements of recycle technique for the decrease construction wastes are going on. Among of them, precast structure method is able to use the limited resources effectively and minimize the construction wastes. The basic study presented in this paper provides the research trends of PC system for accomplishing the sustainable building.