• Structural Engineering and Mechanics
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• 제1권1호
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• pp.17-30
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• 1993

A practical multi-spring model is proposed for a nonlinear analysis of reinforced concrete members, especially columns, taking into account the interaction of axial load and bi-directional bending moment. The parameters of the model are determined on the basis of material properties and section geometry. The axial force-moment interaction curve of reinforced concrete sections predicted by the model was shown to agree well with those obtained by the flexural analysis utilizing realistic stress-strain relations of materials. The reliability of the model was also examined with respect to the test of reinforced concrete columns subjected to varying axial load and bi-directional lateral load reversals. The analytical results agreed well with the experiment.

• 한국지진공학회논문집
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• 제8권4호
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• pp.1-10
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• 2004

반복 횡하중을 받는 콘트리트 충진 탄소섬유 튜브 기둥의 휨거동을 분석하기 위하여 실험을 수행하였다. 콘크리트 충진 각형 탄소섬유 튜부 기둥의 휨거동에 영향을 미치는 탄소섬유의 와인딩 각도와 두께를 변수로 선택하여 거동을 평가하였다. 콘트리트 충진 탄소섬유 튜브 기둥의 휨거동 보다 정확하게 분석하기 위하여 설정된 두 변수를 동시에 고려하였다. 실험의 결과에서 얻어진 하중-변형 곡선을 이용하여 콘크리트 충진 각형 탄소섬유 튜브 기둥이 휨강도, 변형능력 및 에너지 소산능력을 조사하였다. 또한 기존 구조물과의 비교를 위하여 철근콘크리트 조적벽과 콘크리트를 충진한 각형 탄소섬유 튜브 기둥과의 연성 능력을 비교 평가하였다.

• 한국지진공학회논문집
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• 제8권3호
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• pp.13-22
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• 2004

반복 횡하중을 받는 콘크리트 충진 탄소섬유 튜브 기둥의 휨 거동을 분석하기 위하여 여섯 개의 시험체에 대한 실험을 수행하였다. 콘크리트 충진 탄소섬유 튜브 기둥의 휨 거동에 영향을 미치는 탄소섬유의 와인딩 각도와 두께를 변수로 선택하여 거동을 평가하였다. 콘크리트 충진 탄소섬유 튜브 기둥의 휨 거동을 보다 정확하게 분석하기 위하여 설정된 두 변수를 동시에 고려하였다. 실험의 결과에서 얻어진 하중-변형 곡선을 이용하여 콘크리트 충진 탄소섬유 튜브 기둥의 휨강도, 변형능력 및 에너지 소산능력을 조사하였다. 또한 기존 구조물과의 비교를 위하여 철근콘크리트 조적벽과 콘크리트를 충진한 탄소섬유 튜브 기둥과의 연성 능력을 비교 평가하였다.

• 콘크리트학회논문집
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• 제12권1호
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• pp.53-60
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• 2000

The objective of this study is to investigate the flexural behavior of reinforced concrete columns confined by lateral ties. This test was carried on the twelve reinforced concrete columns subjected to lateral and constant axial loads. The main experimental variables are concrete strength, the configuration of lateral ties, and the amount of lateral ties. Test results indicated that the steel configuration in column sections plays an important role in column behavior, and a proper configuration of lateral ties can obtain more ductile by the reduction of the space of lateral ties. Also, this experiment show that the utlization of high-strength concrete in columns properly designed on ACI Code takes less ductile. Therefore, we can conclude that the design of high-strength concrete columns under high axial loads requires more lateral ties than ACI Code.

• 한국강구조학회 논문집
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• 제17권4호통권77호
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• pp.431-438
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• 2005

철골-콘크리트 합성 기둥(이하 SC 합성 기둥)은 철골 플랜지 사이를 연결재로 용접하고, 이런 플랜지 사이에 콘크리트를 채워 시공성과 경제성을 얻을 수 있는 새로운 합성 부재이다. 이 연구의 전단계로서 비조밀단면을 사용한 SC 합성 기둥의 축력 실험을 통해 구조 내력이 우수하다는 것을 입증하였으나, 기둥의 특성상 축력과 휨을 동시에 받고 있기 때문에 후속 실험 연구가 필요하게 되었다. 따라서 일정 축력을 받는 비조밀단면을 가진 SC 합성 기둥의 휨 성능을 강축 및 약축 방향으로 실험을 실시하여 각국 기준식과 비교하여 분석하였다. 실험 결과 모든 방향에 대해서 각국 기준식에서 제시하고 있는 축력-휨 모멘트 내력식을 만족하는 결과를 보이고 있었다. 특히 AISC-LRFD 기준식은 합성 기둥의 내력을 지나치게 안전측으로 고려하고 있다. 또한 추후 SC 합성 기둥의 축력-휨 모멘트 내력식은 EC4 기준식으로 산정하는 것이 철골과 콘크리트의 적합 조건을 고려하지 않은 일본 기준식과 약축 방향 내력을 산정하기 어려운 ACI 기준식보다는 바람직하다.

• 한국강구조학회 논문집
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• 제17권1호통권74호
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• pp.45-52
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• 2005

본 연구의 대상은 두개의 박판 냉간성형 C형강 스터드와 벽체 마감재로 구성되어 있다. 보거동 해석에서는 풍하중을 받고 있는 벽체로 가정하여 패널 축방향에 대하여 횡방향으로 등분포하중이 작용하는 단순지지보로 간주하여 해석한다. 그리고 합성패널의 주요 강도감소인자를 고려한 처짐을 산정한다. 또한 기둥거동에서는 합성패널을 내력벽으로 가정하여 축방향 압축력이 작용하는 기둥으로 간주하여 해석한다. 이 패널은 근사해법인 에너지법을 사용하여 휨 좌굴 하중과 휨-비틂 좌굴 하중을 고려한 공칭 압축강도를 산정할 수 있다. 상기과정은 개발된 전산 프로그램을 이용하여 가용한 실험 결과와 비교하여 검증된다. 보거동에 있어서 실험치가 이론치의 97%의 근사치를 보였고, 기둥거동에서도 이론치에 대한 실험치 압축강도가 유사함을 보였다.

• Steel and Composite Structures
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• 제22권2호
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• pp.217-234
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• 2016

In order to investigate mechanical properties and load-bearing capacity of T-shaped Concrete-Filled Square Steel Tubular (TCFST) composite columns under eccentric axial load, three T-shaped composite columns were tested under eccentric compression. Experimental results show that failure mode of the columns under eccentric compression was bending buckling of the whole specimen, and mono column performs flexural buckling. Specimens behaved good ductility and load-bearing capacity. Nonlinear finite element analysis was also employed in this investigation. The failure mode, the load-displacement curve and the ultimate bearing capacity of the finite element analysis are in good agreement with the experimental ones. Based on eccentric compression test and parametric finite element analysis, the calculation formula for the equivalent slenderness ratio was proposed and the bearing capacity of TCFST composite columns under eccentric compression was calculated. Results of theoretical calculation, parametric finite element analysis and eccentric compression experiment accord well with each other, which indicates that the theoretical calculation method of the bearing capacity is advisable.

• 한국강구조학회 논문집
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• 제8권4호통권29호
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• pp.85-94
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• 1996

This paper investigated structural behaviors of joint of concrete filled steel tube column and P.C reinforced concrete beam through a series of hysteretic behavior experiment. The results are summarised as follows: (1) The joint stiffness of concrete filled square steel tube column and P.C reinforecd beam was higher than that of concrete filled circular steel tube column and P.C reinforecd beam, and it was decreased as the increase of the number of hysteretic cycle. (2) The aspects of the hysteretic behavior in the joint was stable as the increase of the number of hysteretic cycle, and rotation resisting capacity of joint of concrete filled square steel tube column and P.C reinforced concrete beam was higher than those of the concrete filled circular steel tube column and P.C reinforced concrete beam. (3) Some restriction must be put upon the ratio of axial force in this joint model because the load carrying capacity was decreased by flexural and flexural-torsional buckling in case of the ratio of axial force 0.6. (4) The emprical formula to predict the ultimate capacity of joint model to superimpose shearing strength of steel web(H section) and bending strength of reinforced concrete beam was expected.

• Structural Engineering and Mechanics
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• 제76권4호
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• pp.465-477
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• 2020

This paper presents an investigation on the dynamic behavior of SRC columns with built-in cross-shaped steels under impact load. Seven 1/2 scaled SRC specimens were subjected to low-speed impact by a gravity drop hammer test system. Three main parameters, including the lateral impact height, the axial compression ratios and the stirrup spacing, were considered in the response analysis of the specimens. The failure mode, deformation, the absorbed energy of columns, as well as impact loads are discussed. The results are mainly characterized by bending-shear failure, meanwhile specimens can maintain an acceptable integrity. More than 33% of the input impact energy is dissipated, which demonstrates its excellent impact resistance. As the impact height increases, the flexural cracks and shear cracks observed on the surface of specimens were denser and wider. The recorded time-history of impact force and mid-span displacement confirmed the three stages of relative movement between the hammer and the column. Additionally, the displacements had a notable delay compared to the rapid changes observed in the measured impact load. The deflection of the mid-span did not exceed 5.90mm while the impact load reached peak value. The impact resistance of the specimen can be improved by proper design for stirrup ratios and increasing the axial load. However, the cracking and spalling of the concrete cover at the impact point was obvious with the increasing in stiffness.

• International Journal of Concrete Structures and Materials
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• 제18권1E호
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• pp.55-61
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• 2006

RC shear walls are frequently used as lateral force-resisting system in building construction because they have sufficient stiffness and strength against damage and collapse. If RC shear walls are properly designed and proportioned, these walls can also behave as ductile flexural members like cantilevered beams. To achieve this goal, the designer should provide adequate strength and deformation capacity of shear walls corresponding to the anticipated deformation level. In this study, the level of demands for deformation of shear walls was investigated using a displacement-based design approach. Also, deformation capacities of shear walls are evaluated through laboratory tests of shear walls with specific transverse confinement widely used in Korea. Four full-scale wall specimens with different wall boundary details and cross-sections were constructed for the experiment. The displacement-based design approach could be used to determine the deformation demands and capacities depending on the aspect ratio, ratio of wall area to floor plan area, flexural reinforcement ratio, and axial load ratio. Also, the specific boundary detailing for shear wall can be applied to enhance the deformation capacity of the shear wall.