• 제목/요약/키워드: concrete filled steel tubular column

검색결과 169건 처리시간 0.021초

Inelastic stability analysis of high strength rectangular concrete-filled steel tubular slender beam-columns

  • Patel, Vipulkumar Ishavarbhai;Liang, Qing Quan;Hadi, Muhammad N.S.
    • Interaction and multiscale mechanics
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    • 제5권2호
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    • pp.91-104
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    • 2012
  • There is relatively little numerical study on the behavior of eccentrically loaded high strength rectangular concrete-filled steel tubular (CFST) slender beam-columns with large depth-to-thickness ratios, which may undergo local and global buckling. This paper presents a multiscale numerical model for simulating the interaction local and global buckling behavior of high strength thin-walled rectangular CFST slender beam-columns under eccentric loading. The effects of progressive local buckling are taken into account in the mesoscale model based on fiber element formulations. Computational algorithms based on the M$\ddot{u}$ller's method are developed to obtain complete load-deflection responses of CFST slender beam-columns at the macroscale level. Performance indices are proposed to quantify the performance of CFST slender beam-columns. The accuracy of the multiscale numerical model is examined by comparisons of computer solutions with existing experimental results. The numerical model is utilized to investigate the effects of concrete compressive strength, depth-to-thickness ratio, loading eccentricity ratio and column slenderness ratio on the performance indices. The multiscale numerical model is shown to be accurate and efficient for predicting the interaction buckling behavior of high strength thin-walled CFST slender beam-columns.

Influence of slenderness on axially loaded square tubed steel-reinforced concrete columns

  • Yan, Biao;Gan, Dan;Zhou, Xuhong;Zhu, Weiqing
    • 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.

CFCT 단주의 최대내력에 관한 연구 (Ultimate Compressive Strength of Concrete Filled Circular Stub Columns)

  • 강현식;문태섭
    • 한국강구조학회 논문집
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    • 제11권2호통권39호
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    • pp.233-240
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    • 1999
  • 콘크리트충전 강관 단주의 최대내력은 강관에 의한 내부 콘크리트의 구속효과로 단순누가에 의한 내력보다도 높게 나타난다는 것은 이미 여러 연구자들에 의해 알려져 있다. 본 연구는 강관의 지름-두께비와 콘크리트 강도 그리고 등가 세장비의 변화에 따른 내력 예측식을 여러 연구자들의 실험결과를 이용하여 비교 분석하고 회귀식을 구한다.

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시공단계를 고려한 피복충전형 콘크리트충전 각형기둥의 구조적 거동 분석 (Structural Behavior Analysis of Concrete Encased and Filled tube Square Column with Construction Sequence)

  • 김선희;염경수;최성모
    • 한국강구조학회 논문집
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    • 제27권1호
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    • pp.43-52
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    • 2015
  • 구조물의 기둥은 층에 따라 받는 내력이 상이함에도 시공의 오차를 줄이고 구조설계의 편의를 위해 상부층부터 하부층의 기둥단면은 동일하게 설계되고 있다. 그럼에도 불가피하게 상하부의 기둥의 단면이 상이하는 경우가 발생된다. 예를들어 초고층 구조물 또는 증축 및 보수에 의해 기둥을 보강할 경우이다. 이렇듯. 선 기둥과 후 피복이 되는 기둥을 피복충전형 콘크리트 충전기둥이라 할 때, 가력조건이 다르므로 재하상태를 나뉘어 구조적 안정성을 확인할 필요가 있다. 그럼에도 국내외적으로 가력조건에 따른 합성기둥에 대한 내력과 변형연구는 전무한 상태에 있다. 따라서 본 연구에서는 구조실험을 통해 가력조건 및 콘크리트 강도, 피복두께 변화에 의한 피복충전형 콘크리트 각형 기둥의 내력과 거동을 분석하였다.

The combined reinforcement to recycled aggregate concrete by circular steel tube and basalt fiber

  • Zhang, Xianggang;Zhang, Songpeng;Chen, Xu;Gao, Xiang;Zhou, Chunheng
    • Computers and Concrete
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    • 제29권 5호
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    • pp.323-334
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    • 2022
  • In order to study the axial compression performance of basalt-fiber reinforced recycled concrete (BFRRC) filled circular steel tubular short columns, the axial compression performance tests of seven short column specimens were conducted to observe the mechanical whole-process and failure mode of the specimens, the load-displacement curves and the load-strain curves of the specimens were obtained, the influence of design parameters on the axial compression performance of BFRRC filled circular steel tubular short columns was analyzed, and a practical mathematical model of stiffness degradation and a feasible stress-strain curve equation for the whole process were suggested. The results show that under the axial compression, the steel tube buckled and the core BFRRC was crushed. The load-axial deformation curves of all specimens show a longer deformation flow amplitude. Compared with the recycled coarse aggregate (RCA) replacement ratio and the basalt fiber dosage, the BFRRC strength has a great influence on the peak bearing capacity of the specimen. The RCA replacement ratio and the BFRRC strength are detrimental to ductility, whereas the basalt fiber dosage is beneficial to ductility.

The behavior of concrete filled steel tubular columns infilled with high-strength geopolymer recycled aggregate concrete

  • Rajai Z. Al-Rousan;Haneen M. Sawalha
    • Steel and Composite Structures
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    • 제51권6호
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    • pp.661-678
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    • 2024
  • The utilization of geopolymer recycled aggregate concrete (GRAC) as the infilled core of the concrete-filled steel tubular (CFST) columns provides superior economic and environmental benefits. However, limited research exists within the field of geopolymer recycled aggregate concrete considered a green and sustainable material, in addition to the limitation of the design guidelines to predict the behavior of such an innovative new material combination. Moreover, the behavior of high-strength concrete is different from the normal-strength one, especially when there is another material of high-strength properties, such as the steel tube. This paper aims to investigate the behavior of the axially loaded square high-strength GRACFST columns through the nonlinear finite element analysis (NLFEA). A total of thirty-two specimens were simulated using ABAQUS/Standard software with three main variables: recycled aggregate replacement ratio (0, 30, and 50) %, width-to-thickness ratios (52.0, 32.0, 23.4, and 18.7), and length-to-width ratio (3, 5, 9, and 12). During the analysis, the response in terms of the axial load versus the longitudinal strain was recorded and plotted. In addition, various mechanical properties were calculated and analyzed. In view of the results, it has been demonstrated that the mechanical properties of high-strength GRACFST columns such as ultimate load-bearing capacity, compressive stiffness, energy absorption capacity, and ductility increase with the increase of the steel tube thickness owing to the improvement of the confinement effect of the steel tube. In contrast, the incorporation of the recycled aggregate adversely affected the mentioned properties except the ductility, while the increase of the recycled aggregate replacement ratio improved the column's ductility. Moreover, it has been found that the increase in the length-to-width ratio significantly reduced both the failure strain and the energy absorption capacity. Finally, the obtained NLFEA results of the ultimate load-bearing capacity were compared with the corresponding predicted capacities by numerous codes. It has been concluded that AISC, ACI, and EC give conservative predictions for the ultimate load-bearing capacity since the confinement effect was not considered by these codes.

Beam-column behavior of concrete filled steel tubes

  • Campione, G.;Scibilia, N.
    • Steel and Composite Structures
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    • 제2권4호
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    • pp.259-276
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    • 2002
  • In the present investigation the experimental and theoretical flexural and compressive behavior of short tubular steel columns filled with plain concrete and fiber-reinforced concrete (FRC) was examined. For a given length of the members, the effects of different geometry and dimensions of the transverse cross-section (square and circular) were investigated. Constituent materials were characterized through direct tensile tests on steel coupons and through compressive and split tension tests on concrete cylinders. Load-axial shortening and load-deflection curves were recorded for unfilled and composite members. Finally, simplified expressions for the calculus of the load-deflection curves based on the cross-section analysis were given and the ultimate load of short columns was predicted.

T 스티프너를 이용한 CFT기둥-H 형강보 실대형 접합부의 비선형 해석 (Non-linear Analysis of Full Scaled CFT Column to H-Beam Connections with T-Stiffeners)

  • 이승우;김영주;신경재;오영석;문태섭
    • 한국강구조학회 논문집
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    • 제14권6호
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    • pp.835-843
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    • 2002
  • 본 논문은 외부 T스티프너로 보강한 콘크리트 충전각형강관-H형강보 접합부의 응력전달 메카니즘을 유한요소해석을 통해 정확히 이해하고, T스티프너에 관한 설계기본자료를 제공하는데 그 목적이 있다. 따라서 선행된 실대형 접합부의 실험결과와 비선형 유한요소해석의 결과를 비교함으로써 유한요소해석의 신뢰도를 높였다. 유한요소해석에서 접합부의 응력전달 메카니즘을 이해하기 위해 여러 가지의 응력 및 변형도 지수를 사용하였고, 유한요소해석을 통하여 실험에서 발견된 보플랜지와 수평스티프너 접합부의 응력집중을 감소시킬수 있는 방안을 모색하였다.

재하가열시험에 의한 무내화피복 콘크리트충전 각형강관기둥의 내화성능평가 (Evaluation of Fire Resistance of Unprotected Concrete-filled Rectangular Steel Tubular Columns under Axial Loading)

  • 안재권;이철호
    • 한국강구조학회 논문집
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    • 제26권4호
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    • pp.323-334
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    • 2014
  • 본 연구에서는 표준화재에 노출된 무피복 콘크리트충전강관(CFT)기둥의 내화성능 및 거동 특성을 파악하고자 화재실험 및 수치해석 연구를 수행하였다. 실험변수로는 기둥높이, 하중비, 단면크기를 고려하였고, 이들이 CFT 기둥의 내화성능에 미치는 영향을 알아보고자 단면내 온도변화 및 축변형을 분석하였다. 실험결과 모든 실험체의 강관에서 국부좌굴이 발생, 콘크리트로 하중전이가 일어났고, 이후 콘크리트 압괴로 이어졌다. 이는 CFT 기둥의 전체 휨좌굴과 함께 국부좌굴이 내화설계의 주요 변수로 고려되어야 함을 시사한다. 하중비가 증가할수록 콘크리트저항구간이 줄어들면서 전체적인 내화시간이 감소하였다. 강재한계온도에 근거한 합성부재의 내화성능평가는 실제 하중지지력에 의한 내화시간에 비해 다소 보수적임을 확인하였고, 기존 연구자들의 제안식에 의한 성능예측결과도 실제 내화성능과 비교해볼때 개선의 여지가 있었다. 화재시 CFT 기둥의 내화성능을 예측하기 위하여 유한요소해석을 수행하였고, 실험결과와 비교할 때 신뢰성 있는 예측값을 나타냄을 확인하였다.

철근을 이용한 충전 강관기둥 접합부의 인장거동 (Tensile Behavior of Concrete-Filled Column Connections Using Re-bars)

  • 이영렬;유영찬;신경재;오영석;이승준;문태섭
    • 한국강구조학회 논문집
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    • 제8권3호통권28호
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    • pp.89-96
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    • 1996
  • The objective of this study is to investigate the structural behavior of Concrete-Filled Steel Tubular Column connections using reinforced bar. The parameter of specimens is the area of each reinforced bar (SD40 : D13, D16, D19, D22, D25). The simple tensile experiment is conducted to 5 kinds of specimens. Estimating the load, displacement, and strain from each kind, we compared them to basic elementary type (Flange Type, Basic Type, DPA Type, DPB Type). In each specimen, We can get the yielding load obtained by the theoretical three failure modes which make it possible to predict the experimental results. Actually, through the comparison and analysis, we come to know that the experimental results and theoretical results are nealy the same. Further, we will exert to apply the connections using reinforced bar to construction of high-rise building.

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