• 한국강구조학회 논문집
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• 제10권2호통권35호
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• pp.177-186
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• 1998

콘크리트 충전 강관 기둥은 동일 단면의 비충전 강관 기둥에 비해 압축 내력이 우수하며 충전 콘크리트에 의한 강성의 향상, 국부좌굴 보강 효과에 의한 인성의 향상 등과 같은 구조적으로 우수한 점이 많다. 그러나. 강관과 충전 콘크리트의 상호작용 효과, 응력 분담율, 콘크리트의 파괴 양상 등에 대해서는 불분명한 점들이 많다. 본 연구는 일련의 실험을 통하여 고강도 콘크리트 충전 강관 기둥에 대해 재하 조건에 따른 구조적인 거동 특성에 대해 고찰하였다. 특히, 본 연구에서는 재하조건에 따른 강관과 콘크리트의 응력 분담율, 충전 콘크리트의 파괴 양상등에 대해 조사 하였다.

• Steel and Composite Structures
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• 제44권1호
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• pp.141-154
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• 2022

This paper describes the experimental and numerical investigation on circular and octagonal CFDST short columns under concentric loading to study their responses to various internal circular steel tube sizes by the constant cross-sectional dimensions of the external circular and octagonal steel tube. The non-linear finite element analysis of circular and octagonal CFDST columns was executed using the ABAQUS to forecast and compare the axial behavior influenced by the various sizes of internal circular steel tubes. The study shows that the axial compressive strength and ductility of circular and octagonal CFDST columns were significantly influenced by inner steel tubes with the strengths of constituent materials.

• 한국강구조학회 논문집
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• 제10권2호통권35호
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• pp.211-219
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• 1998

본 논문의 목적은 단순재하시 관통형 고력볼트를 사용한 엔드플레이트형식 콘크리트충전 각형강관기둥 H형강 보 접합부의 구조적 거동에 관해 파악하는 것이다. 보를 포함한 5개의 시험체에 대해 단순가력 실험이 이루어졌다. 실험의 주요변수는 엔드플레이트의 두께가 증가할수록, 볼트직경이 커질수록 증가하는 것으로 나타났다. 각 시험체에 대한 Bjorhovde와 Eurocode 3에 의한 분류방법에 따르면 초기강성과 최대내력에 대해서 모두 강접영역에 속하는 것으로 나타났다.

• Earthquakes and Structures
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• 제18권6호
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• pp.677-689
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• 2020

A building structural system of moment resisting frame (MRF) with concrete filled steel tubular (CFST) columns and wide flange H beams, is one of the most conveniently constructed structural systems. However, there were few studies on evaluating seismic performance of full-scale CFST columns under high axial compression. In addition, some existing famous design codes propose various limits of width-to-thickness ratio (B/t) for steel tubes of the ductile CFST composite members. This study was intended to investigate the seismic behavior of CFST columns under high axial load compression. Four full-scale square CFST column specimens with a B/t of 42 were carried out that were subjected to horizontal cyclic-reversal loads combined with constantly light, medium and high axial loads and with a linearly varied axial load, respectively. Test results revealed that shear strength and deformation capacity of the columns significantly decreased when the axial compression exceeded 0.35 times the nominal compression strength of a CFST column, P₀. It was obvious that the higher the axial compression, the lower both the shear strength and deformation capacities were, and the earlier and faster the shear strength degradation occurred. It was found as well that higher axial compressions resulted in larger initial lateral stiffness and faster degradation of post-yield lateral stiffness. Meanwhile, the lower axial compressions led to better energy dissipation capacities with larger cumulative energy. Moreover, the study implied that under axial compressions greater than 0.35P₀, the CFST column specimens with B/t limits recommended by AISC 360 (2016), ACI 318 (2014), AIJ (2008) and EC4 (2004) codes do not provide ultimate interstory drift ratio of more than 3% radian, and only the limit in ACI 318 (2014) code satisfies this requirement when axial compression does not exceed 0.35P₀.

• 한국강구조학회 논문집
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• 제17권2호통권75호
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• pp.207-216
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• 2005

본 논문은 스테인리스 각형강관 및 원형강관에 대한 좌굴내력에 관한 연구로서 건축구조용 강재로서의 적용성 검토를 위해, 세장비를 주요 변수로 한 소재의 인장강도실험과 stub-column의 압축강도실험, 기둥의 중심압축실험을 실시하여 강재의 기계적 성질과 기둥의 강도 및 거동을 파악한다. 또한 이론해석과 각국 기준식(AIK-LSD, AISC-LRFD, AIJ-LSD, SIJ-ASD) 및 복수강도곡선의 적용을 통한 이론값과 실험값을 비교함으로서 건축구조용 강재로서 적용성 검토와 구조설계기준 확립을 위한 기초 자료를 구하는데 목적이 있다.

• Steel and Composite Structures
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• 제33권3호
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• pp.375-388
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• 2019

This paper aims to investigate the axial load behavior and stability strength of square tubed steel-reinforced concrete (TSRC) columns. Unlike concrete filled steel tubular (CFST) column, the outer steel tube of a TSRC column is mainly used to provide confinement to the core concrete. Ten specimens were tested under axial compression, and the main test variables included length-to-width ratio (L/B) of the specimens, width-to-thickness ratio (B/t) of the steel tubes, and with or without stud shear connectors on the steel sections. The failure mode, ultimate strength and load-tube stress response of each specimen were summarized and analyzed. The test results indicated that the axial load carried by square tube due to friction and bond of the interface increased with the increase of L/B ratio, while the confinement effect of tube was just the opposite. Parametric studies were performed through ABAQUS based on the test results, and the feasibility of current design codes has also been examined. Finally, a method for calculating the ultimate strength of this composite column was proposed, in which the slenderness effect on the tube confinement was considered.

• 한국강구조학회 논문집
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• 제26권1호
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• pp.31-42
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• 2014

본 연구에서는 콘크리트충전 각형강관에 구조용 피복콘크리트를 적용한 합성기둥에 대하여 연구하였다. 1/3~1/2 축소모델의 편심 압축실험체 4개와 중심압축실험체 1개를 제작하여 압축실험을 수행하였다. 실험 변수는 피복콘크리트의 강섬유 첨가여부, 편심거리, 기둥 길이, 그리고 횡보강 상세이다. 일부 실험체에서 최대강도 도달 후 피복콘크리트의 탈락으로 인한 강도저하가 발생하였으나 모든 실험체는 현행 설계기준(KBC 2009)에 의한 휨 압축 강도 및 공칭 압축강도를 초과하는 하중재하능력을 보였다.

• 복합신소재구조학회 논문집
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• 제6권2호
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• pp.23-31
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• 2015

CFST columns are structurally superior because the concrete inside the steel tubes prevents local buckling at the tubes and the tubes confine the concrete. And, the thickness of steel tube in CFST column has been thinner with development of high-strengh steel. The thinner the steel tube of a square CFST column is, the more local buckling is likely to occur. For this reason, we developed welded built-up square steel tube with stiffeners which are placed at the center of the tube width acts as an anchor. In this study, we conduct experimental test for three specimens of the 4m long span welded built-up square CFT column with parameters of L/D and D/t. And, the test results were compared with the analysis results by M-${\phi}$-P Program.

• Structural Engineering and Mechanics
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• 제55권1호
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• pp.205-228
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• 2015

The results of a numerical investigation pertaining to the hysteretic behaviour of concrete filled steel tubular (CFT) column to I-beam connections are discussed in detail. Following the verification of the numerical results against the available experimental tests, the nonlinear finite element (FE) analysis was implemented to evaluate the effects of different parameters including the column axial load, beam lateral support, shape and arrangement of stiffeners, stiffness of T-stiffeners, and the number of shear stiffeners. Pursuing this objective, an external CFT column to beam connection, tested previously, was selected as the case-study. The lateral forces on the structure were simulated, albeit approximately, using an incremental cyclic loading reversal applied at the beam tip. The results were compared in terms of hysteretic load-displacement curves, stress distributions in connection, strength, rotation, and energy dissipation capacity. It was shown that external T-stiffeners combined with internal shear stiffeners play an important role in the hysteretic performance of CFT columns to I-beam connections.

• 한국강구조학회 논문집
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• 제14권6호
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• pp.813-822
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• 2002

단주영역에서 정사각형 콘크리트 충전 강관기둥의 단순 누가강도, 설계식 강도는 실험강도에 비해 약간 과소하게 평가하고 있다. 따라서 본 논문은 주요 요인이 되는 콘크리트의 구속효과를 고려하여 평가하고자 하였다. 콘크리트의 구속효과를 검토하기 위해 3차원 유한요소모델을 사용하여 강관의 폭-두께비(b/t), 콘크리트의 압축강도($f_c$'), 강재의 항복응력($f_y$)에 따른 영향을 검토하였고 이 세 변수를 조합한 제안된 강도식은 기존의 실험값과 비교, 검토되었다. 또한 하중 재하상태에 따른 콘크리트의 구속효과도 살펴 보았다.