• Steel and Composite Structures
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• 제4권5호
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• pp.403-418
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• 2004

Lateral sway is most likely to control the design of semi-rigid steel frames where the frame arrangements do not include any form of bracing. This paper investigates the sway behaviour of semi-rigid regular steel frames i.e., frames having the same arrangement of beam and column sections at all levels, and hence proposes some design charts for the prediction of sway that eliminate the need for doing any numerical modelling. Schueller's equation has also been modified to incorporate connection flexibility in addition to its original rigid frame considerations. All the proposed methods have been validated using results obtained from numerical analysis.

• 한국디지털건축인테리어학회논문집
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• 제4권1호
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• pp.36-45
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• 2004

Allowable stress design method have been most widely used in steel structure in Korea. Recently, not only high-rise buildings but also medium or low-rise buildings were designed as steel structure. Most of low-rise steel buildings are designed as ordinary moment resisting frames(MRF). But MRFs don't have any lateral force resisting devices such as bracing in braced frames. This study focuses mainly on nonlinear seismic response analyses of small scale steel frames which will be used later as specimens for the evaluation of MRF's seismic performances. The main parameters of analyses are arrangement of column axis, $P-{\Delta}$ effect, acceleration factor etc. The object of this paper is to estimate the seismic performances of MRFs, which are mostly designed in Korea, through the results of response analyses.

• 한국세라믹학회지
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• 제42권5호
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• pp.304-307
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• 2005

The possible configurations of hydroxyl group in hexagonal hydroxyapatite were identified through molecular orbital calculation. The molecular orbital interaction between O and H in hydroxyl column was analyzed using charge variation and Bond Overlap Population (BOP). We supposed 5 kinds of O-H bond configurations as cluster types of I, II, III, IV, and V. Mulliken's population analysis was applied to evaluate ionic charges of O, H, P, and Ca ions, and BOPs (Bond Overlap Populations) in order to discuss the bond strength change by the atomic arrangement. The stability of each O-H bond configuration was analyzed using bond overlap and ionic charge.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권4호
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• pp.357-363
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• 2006

Monolithic molecularly imprinted columns were designed and prepared by an in-situ thermal-initiated copolymerization technique for rapid separation of tryptophan and N- CBZ-phenylalanine enantiomers. The influence of polymerization conditions and separation conditions on the specific molecular recognition ability for enantiomers and diastereomers was investigated. The specious molecular recognition was found to be dependent on the stereo structures and the arrangement of functional groups of the imprinted molecule and the cavities in the molecularly imprinted polymer (MIP). Moreover, hydrogen bonding interactions and hydrophobic interactions played an important role in the retention and separation. Compared to conventional MIP preparation procedures, the present method is very simple, and its macroporous structure has excellent separation properties.

• 한국구조물진단유지관리공학회 논문집
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• 제22권6호
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• pp.81-88
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• 2018

이 연구에서는 실제 단면크기를 갖는 철근 콘크리트 기둥의 내진보강을 위한 단면확대 공법에서 효율적인 띠철근 배근 방법을 평가하였다. 비내진 상세를 갖는 기존 기둥의 단면크기는 $450{\times}450mm$이며, 단면확대 보강기둥의 단면크기는 $750{\times}750mm$이다. 확대 단면에서의 폐쇄형 외부 띠철근 배근을 위해 ㄷ-형 띠철근의 겹칩이음 및 철근 선조립 공법을 제시하였으며, 보조 띠철근으로서 크로스타이 앵커링 시공 및 V-타이를 고려하였다. 실험 결과, 무보강 기둥 및 ㄷ-형 외부 띠철근을 적용한 보강기둥의 압축내력은 ACI 318-14의 공칭내력과 비슷한 수준인 반면 철근 선조립 공법을 적용한 기둥의 압축내력은 ACI 318-14의 공칭내력 대비 1.25배 높았다. 특히 철근 선조립 공법을 적용한 보강 기둥의 압축 연성비는 크기효과에 의한 연성비 저하 가능성에도 불구하고 기존 기둥에 비해 139% 증가하였다. 즉, 제시된 철근 선조립 공법은 단면확대 보강기둥에서 주철근 조기 좌굴방지 및 콘크리트 구속에 효율적인 띠철근 상세로 평가될 수 있었다.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제24권1호
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• pp.195-220
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• 2010

방진 또는 마방진(magic square, 魔方陣)은 정사각형 모양으로 수를 배열하여 가로, 세로, 대각선의 합이 같아지도록 만든 수배열을 말한다. 마방진의 '방'에는 정사각형이라는 의미가 포함되어 있다. 만약 '방' 즉 정사각형이라는 조건을 제거한다면 어떤 수배열이 가능할 것인가? 중국의 "양휘산법"과 "산법통종"에는 취오도(聚五圖)와 취육도(聚六圖), 취팔도(聚八圖), 찬구도(攢九圖), 팔진도(八陣圈), 연환도(連環圖)와 같은 다양한 수배열이 제시되어 있다. 또한 조선 시대 수학자 최석정의 "구수략"에는 지수귀문도(地數龜文圖)라는 독창적이고 아름다운 수배열이 제시되어 있다. 이밖에도 원 모양의 마방진, 별 모양의 마방진 등 다양한 마방진이 존재한다. 본고에서는 이러한 정사각형 형태가 아닌 마방진을 소개하고 이들이 갖는 몇 가지 성질과 이에 대한 활용 방법을 제시하였다.

• 건축역사연구
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• 제25권3호
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• pp.23-35
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• 2016

The purpose of this study is to classify types of the eaves structure of buildings with the Jusimpo-type structure and to analyze the characteristics of each eaves structure. For this objective, forty buildings were selected and investigated. The results of analysis are summarized as follows. First, the main members of framework which handle a load burden on the long-rafter(長椽) are classified as the Jusim-dori(柱心道里) and the Oemok-dori(外目道里). Based on the method of handling a load, the eaves structure is classified into three types; the Jusim-processing-type(柱心中心形), the Oemok-processing-type(外目中 心形), and the Oemok-processing-variant-type(外目中心變異形). The Jusim-processing-type is the set where the internal length of a long-rafter is longer than the length of the eaves on the basis of the center of a column. The Oemok-processing-type is the set where the external length of a long-rafter is longer than the internal length of it. And the Oemok-processing-variant-type is the set where the internal length of a long-rafter is longer than the external length of it, but it is shorter than the length of the eaves which includes the extruded length of a Buyeon(浮椽). Second, the Jusim-processing-type had been generally adopted in the Jusimpo-type structure of the Goryeo Dynasty. But since the 17th century, the Oemok-processing-type had the highest application rate. Third, the change from the Jusimdori-processing-structure to the Oemokdori-processing-structure means that the long-rafter is moved to the direction of outside of the building, and thus the Jung-dori(中道里) is gradually moved to the column center. And, the change of the eaves with the Jusimpo-type structure was not a process for increasing the length of the eaves but a process for adopting the advantages of the Dapo-type structure by changing the arrangement of purlin. Fourth, the change from the Jusimpo-type structure to the Dapo-type structure could be understood as a process for moving the main point for handling a load from the Jusim-dori to the Oemok-dori.

• Steel and Composite Structures
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• 제31권1호
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• pp.99-112
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• 2019

Semi-rigid joints have been widely studied in literature in recent decades because they affect greatly the structural response of frames. In literature, the behavior of semi-rigid joints is commonly assumed to be identical under positive and negative moments which are obviously incorrect in many cases where joint details such as bolt arrangement or placement of haunch are vertically asymmetrical. This paper evaluates two common types of steel frames with asymmetrical beam-to-column joints by Direct Analysis allowing for plasticity. A refined design method of steel frames using a proposed simple forth order curved-quartic element with an integrated joint model allowing for asymmetrical geometric joint properties is presented. Furthermore, the ultimate behavior of six types of asymmetrical end-plate connections under positive and negative moment is examined by the Finite Element Method (FEM). The FEM results are further applied to the proposed design method with the curved-quartic element for Direct Analysis of two types of steel frames under dominant gravity or wind load. The ultimate frame behavior under the two different scenarios are examined with respect to their failure modes and considerably different structural performances of the frames were observed when compared with the identical frames designed with the traditional method where symmetrical joints characteristics were assumed. The finding of this research contributes to the design of steel frames as their asymmetrical beam-to-column joints lead to different frame behavior when under positive and negative moment and this aspect should be incorporated in the design and analysis of steel frames. This consideration of asymmetrical joint behavior is recommended to be highlighted in future design codes.

• Steel and Composite Structures
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• 제21권2호
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• pp.267-287
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• 2016

The seismic performance of the ordinary steel reinforced concrete (SRC) columns has no significant improvement compared to the reinforced concrete (RC) columns mainly because I, H or core cross-shaped steel cannot provide sufficient confinement for core concrete. Two improved SRC columns by constructing with new-type shaped steel were put forward on this background, and they were named as enlarging cross-shaped steel and diagonal cross-shaped steel for short. The seismic behavior and carrying capacity of new-type SRC columns have been researched theoretically and experimentally, while the shear behavior remains unclear when the new-type columns are joined onto SRC beams. This paper presents an experimental study to investigate the shear capacity of new-type SRC joints. For this purpose, four new-type and one ordinary SRC joints under low reversed cyclic loading were tested, and the failure patterns, load-displacement hysteretic curves, joint shear deformation and steel strain were also observed. The ultimate shear force of joint specimens was calculated according to the beam-end counterforce, and effects of steel shape, load angel and structural measures on shear capacity of joints were analyzed. The test results indicate that: (1) the new-type SRC joints display shear failure pattern and has higher shear capacity than the ordinary one; (2) the oblique specimens have good bearing capacity if designed reasonably; and (3) the two proposed construction measures have little effect on the shear capacity of SRC joints embedded with diagonal cross-shaped steel. Based on the mechanism observed from the test, the formulas for calculating ultimate shear capacity considering the main factors (steel web, stirrup and axial compression ratio) were derived, and the calculated results agreed well with the experimental and simulated data.

• 한국강구조학회 논문집
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• 제11권2호통권39호
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• pp.109-116
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• 1999

본 논문은 관통형 고력볼트를 사용한 엔드플레이트형식 콘크리트 충전 각형 강관 기둥 H형강 보 접합부에 대한 단조가력하에서의 실험적 연구이다. 본 실험의 목적은 전회(前回)에서는 파악되지 않았던 엔드플레이트의 두께와 볼트의 배열에 대한 영향을 정확하게 평가하는데 있다. 실험의 주요변수는 엔드플레이트의 두께(12mm, 16mm)와 볼트의 배열 (EP1, EP2, EP3)이다. 변수에 따른 실험결과를 비교, 분석하였다. 1)실험체는 Bjorhovde와 EC3의 분류법에 의해 분류하였다. 2)T-stub모델에 근거한 접합부의 최대 모멘트 예측식에 의해 계산된 이론치$(_tM_u)$는 실험치$(_eM_u)$에 잘 대응하였다.