• 한국지진공학회논문집
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• 제27권1호
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• pp.59-68
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• 2023

The column-tree type steel beam-column connections are commonly used in East Asian countries, including Korea. The welding detail between the stub beam and column is similar to the WUF-W connection; thus, it can be expected to have sufficient seismic performance. However, previous experimental studies indicate that premature slip occurs at the friction joints between the stub and link beams. In this study, for the accurate seismic performance evaluation of column-tree type moment connections, a moment-slip model was proposed by investigating the previous test results. As a result, it was found that the initial slip occurred at about 25% of the design slip moment strength, and the amount of slip was about 0.15%. Also, by comparing the analysis results from models with and without the slip element, the influence of slip on the performance of overall beam-column connections was examined. As the panel zone became weaker, the contribution of slip on overall deformation became greater, and the shear demand for the panel zone was reduced.

• 콘크리트학회논문집
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• 제29권1호
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• pp.77-84
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• 2017

본 연구에서는 고강도 콘크리트 기둥-일반강도 콘크리트 슬래브 접합부의 구속도, 형상비 (h/c), 강도비 ($f^{\prime}_{cc}/f_{cs}$)에 따른 구조거동 분석하였다. 유한요소해석 프로그램을 통해 해석적 연구가 수행되었으며, 해석 방법의 검증을 위하여 기존의 구조 실험과 동일한 조건의 해석 부재를 제작하여 결과를 비교하였다. 부재의 종류는 내부기둥, 외부기둥, 모서리기둥, 독립기둥으로 분류하였으며 내부기둥에서 가장 높은 극한강도를 보였다. 또한 형상비가 증가할수록 접합부에 작용하는 축방향 응력이 작게 나타났으며 강도비가 증가할수록 부재의 극한강도가 상승하였으나 1.83이후로는 뚜렷한 강도 증진을 나타내지 않았다.

• Structural Engineering and Mechanics
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• 제24권3호
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• pp.291-306
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• 2006

In order to improve the constructability and meanwhile ensure excellent seismic behavior, several innovative composite connection details were conceived and studied by the authors. This paper reports experimental results and observations on seismic behavior of steel beam bolted to reinforced concrete column connections (bolted RCS or BRCS). The proposed composite connection details involve post tensioning the end plates of the steel beams to the reinforced concrete or precast concrete columns using high-strength steel rods. A rational design procedure was proposed to assure a ductile behavior of the composite structure. Strut-and-tie model analysis indicates that a bolted composite connection has a favorable stress transfer mechanism. The excellent capacity and behavior were then validated through five full-scale beam to column connection model tests.

• Steel and Composite Structures
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• 제15권6호
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• pp.585-603
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• 2013

Generally the required strength and stiffness of an I-shaped beam to the box-shaped column connection is achieved if continuity plates are welded to the column flanges from all sides. However, welding the forth edge of a continuity plate to the column flange may not be easily done and is normally accompanied by remarkable difficulties. This study was aimed to propose an alternative for box columns with continuity plates to diminish such problems. For this purpose a double-web I-shaped column was proposed. In this case the strength and rotational stiffness of the connection was provided by nearing the column webs to each other. Finite element studies on about 120 beam-column connections showed that the optimum proportion of the distance between two column webs and the width of the column flange (parameter ${\beta}$) was a function of the ratio of the beam flange width to the column flange width (parameter ${\alpha}$). Hence, based on the finite element results, an equation was proposed to estimate the optimum value of parameter ${\beta}$ in terms of parameter ${\alpha}$ to achieve the highest connection performance. Results also showed that the strength and ductility of post-Northridge connections of such columns are in average 12.5 % and 54% respectively higher than those of box-shaped columns with ordinary continuity plates. Therefore, a double-web I-shaped column of optimum arrangement might be a proper replacement for a box column with continuity plates when beams are rigidly attached to it.

• Earthquakes and Structures
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• 제8권5호
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• pp.1039-1054
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• 2015

The purpose of this study was to evaluate the seismic performance of weak-axis column-tree type connections used in steel moment frames. These connections are composed of a shop-welded and fieldbolted steel structure and can improve welding quality. On this basis, column-tree type connections are widely used in steel moment resisting frames in Korea and Japan. In this study, splices designed with a semirigid concept regarding the seismic performance of column-tree connections were experimentally evaluated. The structures can absorb energy in an inelastic state rather than the elastic state of the structures by the capacity design method. For this reason, the plastic hinge might be located at the splice connection at the weak-axis column-tree connection by reducing the splice plate thickness. The main variable was the distance from the edge of the column flange to the beam splice. CTY series specimens having column-tree connections with splice length of 600 mm and 900 mm were designed, respectively. For comparison with two specimens with the main variable, a base specimen with a weak-axis column-tree connection was fabricated and tested. The test results of three full-scale test specimens showed that the CTY series specimens successfully developed ductile behavior without brittle fracture until 5% story drift ratio. Although the base specimen reached a 5% story drift ratio, brittle fracture was detected at the backing bar near the beam-to-column connection. Comparing the energy dissipation capacity for each specimen, the CTY series specimens dissipated more energy than the base specimen.

• 대한토목학회논문집
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• 제37권2호
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• pp.451-457
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• 2017

본 연구에서는 폭발하중을 받는 슬래브-기둥 접합부의 거동을 해석적으로 분석하였다. 슬래브-기둥의 거동을 분석하기 위해 유한요소해석프로그램 LS-DYNA를 사용하여 폭발해석을 수행하였다. 대상 접합부의 형태는 일반적인 내부기둥형태의 슬래브-기둥 접합부와 기둥주위에 드롭패널(drop panel)을 보강한 접합부로 설정하였다. 또한, 슬래브에 의한 기둥의 구속도에 따라 내부기둥, 외부기둥 그리고 모서리기둥 시험체를 모델링하여 비교분석이 수행되었다. 해석결과는 접합부의 파괴형상, 단위부재의 거동 등을 포함하고 있다. 해석결과 드롭패널을 보강한 경우 슬래브-기둥 접합부의 거동이 향상되는 것을 확인하였으며 슬래브에 의한 기둥의 구속도가 감소할수록 거동이 저하되는 것을 확인하였다.

• Steel and Composite Structures
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• 제13권5호
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• pp.409-421
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• 2012

Recently, as the height of building is getting higher, the applications of CFST column for high-rise buildings have been increased. In structural system of high-rise building, The RC core and exterior concrete-filled tubular (CFST) column-beam pinned connection is one of the structural systems that support lateral load. If this structural system is used, due to the minimal CFST column thickness compared to that of the CFST column width, the local moment occurred by the eccentric distance between the column flange surface from shear bolts joints degrades the shear strength of the CFST column-beam pinned connections. This study performed a finite element analysis to investigate the shear strength under eccentric moment of the CFST column-beam pinned connections. The column's width and thickness were used as variables for the analysis. To guarantee the reliability of the finite element analysis, an actual-size specimens were fabricated and tested. The yield line theory was used to formulate an shear strength formula for the CFT column-beam pinned connection. the shear strength formula was suggested through comparison on the results of FEM analysis, test and yield lime theory, the shear strength formula was suggested.

• 한국강구조학회 논문집
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• 제17권4호통권77호
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• pp.459-467
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• 2005

본 연구는 외측 다이아프램을 사용하여 현장용접에 의한 각형강관 기둥과 H형강 보를 접합법의 개발에 목적을 둔다. 본 연구에서 제안하고 있는 것은 현장용접을 이용한 외측 보강재에 의한 특정 타입의 기둥-보 접합부이다. 이 접합부의 구조적 거동은 실험적으로 검토되었다. 두 가지 하중 유형 실험은 세부적으로 주어진 실험 변수 하에 수행되었다. 먼저 제안된 접합부의 기본적인 특성을 연구하기 위하여 양단부에서 보를 핀 지지한 후 중앙점에서 기둥을 가력한 대칭 하중재하 실험을 기술하였다. 두 번째는 이 접합부의 구조적 성능을 연구하기 위하여 기둥의 양단은 단순지지로 하고 H형강 보 양단에서 하중을 제어하는 역대칭 하중재하 실험을 기술하였다. 실험 결과, 본 논문에서 제안한 외측 보강재 타입의 접합부는 정량적 평가 방법이라는 것을 알 수 있었다.

• 한국구조물진단유지관리공학회 논문집
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• 제19권6호
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• pp.112-118
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• 2015

최근 도심지에 건설되는 건축물의 초고층화는 기둥에 작용하는 하중을 증가시켜 기둥단면 증가와 사용면적 확보의 어려움을 발생시키고 있다. 이에 최근에는 CFT와 같은 합성기둥의 사용이 증가하고 있는 추세이다. 그러나 CFT 기둥의 경우 폐단면으로 이루어져 있어 보-기둥 접합부 개발의 어려움과 성능저하의 문제가 발생하게 된다. 특히, 원형CFT 기둥과 외다이아프램을 이용한 접합상세 개발의 연구가 미비한 실정이다. 이에 본 연구에서는 Y형 플레이트를 적용한 원형 CFT 기둥-H형강 보 접합부 접합상세를 개발하여 Y형 플레이트를 적용한 접합부 구조성능에 영향을 미치는 Y형 플레이트 폭 및 두께를 주요변수로 설정하여 실험을 통해 구조성능을 평가하였다. 또한 실험체에 사용된 Y형 플레이트는 설계기준에 제시된 장기허용인장력이 Y형 플레이트에 접합된 인장 측 플랜지의 축방향력 이하가 되도록 설계하여 파괴형태를 통해 Y형 플레이트의 구조적 안전성과 성능을 확인하고자 한다.

• Steel and Composite Structures
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• 제10권3호
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• pp.261-279
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• 2010

Generally, a box tube, which is used for an existing square CFT structure, is made by welding four plates. The manufacturing efficiency of this steel tube is poor, and it also needs special welding technology to weld its internal diaphragm and the through diaphragm. Therefore, an interior-anchor-type square steel tube was developed using the method of cold-forming thin plates to prevent welding of the stress concentration position, and to maximize the section efficiency. And, considering of the flow of beam flange load, the efficiency of erection and the weldability of the diaphragm to thin walled steel column, the external diaphragm connection was selected as the suitable type for the welded built-up square CFT column to beam connection. And, an analytical study and tests were conducted to evaluate the structural performance of the suggested connection details and to verify the suggested equations for the connection details. Through this study, the composite effect of the internal anchor to concrete, the resistance and stress distribution of the connections before and after the existing column is welded to the beam, the effective location of welding in connection were analyzed.