• Title, Summary, Keyword: 휨 변형

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Analytical Study on Flexural Behavior of Alkali-Activated Slag-Based Ultra-High-Ductile Composite (알칼리활성 슬래그 기반 초고연성 복합재료의 휨거동 해석)

  • Lee, Bang Yeon
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.7 no.2
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    • pp.158-165
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    • 2019
  • The purpose of this study is to investigate analytically the flexural behavior of beam reinforced by an alkali-activated slag-based fiber-reinforced composite. The materials and mixture proportion were selected to manufacture an alkali-activated slag-based fiber-reinforced composite with high tensile strain capacity over 7% and compressive strength and tension tests were performed. The composite showed a compressive strength of 32.7MPa, a tensile strength of 8.43MPa, and a tensile strain capacity of 7.52%. In order to analyze the flexural behavior of beams reinforced by ultra-high-ductile composite, nonlinear sectional analysis was peformed for four types of beams. Analysis showed that the flexural strength of beam reinforced partially by ultra-high-ductile composite increased by 8.0%, and the flexural strength of beam reinforced fully by ultra-high-ductile composite increased by 24.7%. It was found that the main reason of low improvement in flexural strength is the low tensile strain at the bottom of beam. The tensile strain at bottom corresponding to the flexural strength was 1.38% which was 18.4% of tensile strain capacity of the composite.

The Flexural Behavior of a Square Concrete Filled Carbon Tube Columns under the Constant Axial Force with Reversed Cyclic Lateral Load (축하중과 반복 횡하중을 받는 콘크리트 충진 각형 탄소섬유 튜브 기둥의 휨거동특성)

  • Kim, Hee-Cheul;Hong, Won-Kee;Lee, Hyun-Ju
    • Journal of the Earthquake Engineering Society of Korea
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    • v.8 no.4
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    • pp.1-10
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    • 2004
  • The purpose of this study is to investigate the flexural behavior of square concrete filled carbon tube (CFCT) columns subjected to constant axial load with the cyclic lateral load. Two parameters, wnding angle and thickness of tube, were chosen to evaluate the flexural capacity and behavior of rectangular CFCT columns. Selected two parameters were considered simultaneously in order to evaluate the flexural behavior of a rectangular CFCT columns more precisely. Flexural strength, deformation capacity, ductility and energy dissipation capacity of rectangular CFCT columns were evaluated by calculating the area of load-displacement envelope curves and load-dispalcement hysteresis curves obtained from experiment. Also, the ductile capacity obtained from experiment was compared to that of reinforced masonry wall for the comparison of existing structural element.

The Flexural Behavior of a Circular Concrete Filled Carbon Tube Columns under the Constant Axial Force with Reversed Cyclic Lateral Load (축하중과 반복 횡하중을 받는 콘크리트 충진 원형 탄소섬유 튜브 기둥의 휨거동특성)

  • Hong, Won-Kee;Kim, Hee-Cheul;Chung, Jin-Hun
    • Journal of the Earthquake Engineering Society of Korea
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    • v.8 no.3
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    • pp.13-22
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    • 2004
  • The purpose of this study is to investigate the flexural behavior of circular concrete filled carbon tube(CFCT) columns subjected to constant axial load with the cyclic lateral load. Six numbers of composite columns were tested. Two parameters, winding angle and thickness of tube, were chosen to evaluate the flexural capacity and behavior of CFCT columns. Selected two parameters were considered simultaneously in order to evaluate the flexural behavior of CFCT columns more precisely. Flexural strength, deformation capacity, ductility and energy dissipation capacity of CFCT columns were evaluated by calculating the area of load-displacement envelop curves and load-displacement hysteresis curves obtained from experiment. Also, the ductile capacity obtained from experiment were compared to that of reinforced masonry wall for the comparison of existing structural element.

Failure and Flexural Behavior of Reinforced Concrete Beams Strengthened with CFRP Strips (탄소섬유판(CFRP Strip)으로 보강된 철근콘크리트 부재의 파괴거동 및 휨 거동 특성)

  • Lim, Dong Hwan;Park, Sung Hwan
    • Journal of The Korean Society of Civil Engineers
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    • v.28 no.2A
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    • pp.289-295
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    • 2008
  • The purpose of this study was to examine the flexural behavior of reinforced concrete beams strengthened with CFRP strips. A total of 12 rectangular beams were tested. Test variables in this study were the shapes, bonded length and the number of longitudinal layers of CFRP strips. From the experimental study, flexural capacity of the beams strengthened with CFRP strips significantly increased compared to the reinforced concrete beam without a CFRP strip. Maximum increase of ultimate strength was found about 120% more than the control beam. In this test, most of the strengthened beams failed suddenly due to the debonding of CFRP strips. It is also observed that the debonding of the strip was initiated in the flexural zone of the beam and propagated rapidly to the end of the beam. The ultimate tensile strains of CFRP strips in this test were occurred at the level of 36% of rupture tensile strength of the CFRP strip, and an analytical approach to compute the flexural strength of reinforced beams strengthened with CFRP strips based on the effective stresses was conducted.

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Ultimate Flexural Strength of Cylindrical Steel Shell for Wind Tower (풍력발전 타워용 원형단면 강재 쉘의 극한휨강도)

  • Ahn, Joon Tae;Shin, Dong Ku
    • Journal of Korean Society of Steel Construction
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    • v.27 no.1
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    • pp.109-118
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    • 2015
  • Ultimate flexural buckling strength of cylindrical steel shells for the wind turbine tower structure was investigated by applying the geometrically and materially nonlinear finite element method. The effects of initial imperfection, radius to thickness ratio, and type of steel on the ultimate flexural strength of cylindrical shell were analyzed. The flexural strengths of cylindrical shells obtained by FEA were compared with design flexural strengths specified in Eurocode 3 and AISI. The shell buckling modes recommended in DNV-RP-C202 and the out-of-roundness tolerance and welding induced imperfections specified in Eurocode 3 were used in the nonlinear FE analysis as initial geometrical imperfections. The radius to thickness ratios of cylindrical shell in the range of 60 to 210 were considered and shells are assumed to be made of SM520 or HSB800 steel.

Bending, Free Vibration and Buckling Analysis of Anisotropic Composite Laminated Plate and Shell Structures (비등방성 복합적층판 및 쉘 구조의 휨, 자유진동 및 좌굴해석)

  • Yoon, Seok Ho
    • Journal of Korean Society of Steel Construction
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    • v.11 no.1
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    • pp.55-67
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    • 1999
  • The ratios of elastic to shear modulus of the structures as laminated composite plates and shells, are very large. They are much susceptible to effect of shear deformation. In order to obtain the accurate solutions of laminated composite plate and shells, the effects of shear strain should be considered for the analysis and design of them. Especially, the more exact solution can be obtained in applying to higher-order shear deformation theory. Therefore, in this paper, the third-order shear deformation theory is used to present the distributions of bending, the characteristics of natural frequencies and the buckling load according to the effects of ply orientation, number of layers for the laminated composite plates and shells with simply supported boundary conditions.

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FLEXURE-SHEAR INTERACTION BEHAVIOR OF RC COLUMNS UNDER CYCLIC LOADING (주기하중을 받는 철근콘크리트 기둥의 휨-전단간의 상호거동)

  • DoHyungLee
    • Journal of the Korean Geophysical Society
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    • v.4 no.3
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    • pp.219-226
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    • 2001
  • 본 연구에서는 주기적인 하중하에서의 철근콘크리트 기둥의 이력응답거동을 예측할 수 있는 해석적인 모델의 개발을 다루고 있다. 철근콘크리트 기둥의 비탄성 휨, 전단 및 휨-전단 변형은 개발된 모델을 통하여 주기적인 변위하에서 검토되었다. 개발된 모델들을 포함한 해석치와 실험치와의 비교분석을 통하여 본 연구에서 개발된 모델들의 검증을 실시하였고, 이 비교분석을 통하여 휨-전단간의 상호작용의 중요성을 강조하였으며, 본 연구에서 개발된 모델들의 정확성, 효율성 및 타당성을 입증하였다.

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Flexure-Shear Interaction Behavior of RC Columns under Cyclic Loading (주기하중을 받는 철근콘크리트 기둥의 휨-전단간의 상호거동)

  • Lee, Do-Hyung
    • The Journal of Engineering Research
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    • v.4 no.1
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    • pp.151-158
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    • 2002
  • 본 연구에서는 주기적인 하중하에서의 철근콘크리트 기둥의 이력응답거동을 예측할 수 있는 해석적인 모델의 개발을 다루고 있다. 철근콘크리트 기둥의 비탄성 휨, 전단 및 휨-전단 변형은 개발된 모델을 통항 주기적인 변위하에서 검토되었다. 개발된 모델들을 포함한 해석치와 실험치와의 비교분석를 통하여 본 연구에서 개발된 모델들의 검증을 실시하였고, 이 비교분석을 통하여 휨-전단간의 상호작용의 중요성을 강조하였으며, 본 연구에서 개발된 모델들의 정확성, 효율성 및 타당성을 입증하였다.

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Prediction of Flexural Capacities of Steel-Fiber Reinforced Concrete Beams (강섬유보강 콘크리트보의 휨내력 예측식의 제안)

  • Kim, Woo-Suk;Kwak, Yoon-Keun;Kim, Ju-Bum
    • Journal of the Korea Concrete Institute
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    • v.18 no.3
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    • pp.361-370
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    • 2006
  • The results of previous tests by many researchers have been compiled to evaluate the flexural strength of steel-fiber reinforced concrete beams. Existing prediction equations for flexural strength of such beams were examined, and a new equation based on mechanical and empirical observations, was proposed. In other words, the constitutive models for steel fiber reinforced concrete(SFRC) were proposed, which incorporate compressive and tensile strength. A steel model might also exhibit stain-hardening characteristics. Predictions based on the model are compared with the experimental data. For the collection of tests, a variation of the Henager equations, modified to apply to fiber-reinforced concrete beams, provided reliable estimates of flexural strength. The proposed equations accounted for the influence of fiber-volume fraction, fiber aspect ratio, concrete compressive strength and flexural steel reinforcement ratio. The proposed equations gave a good estimation for 129 flexural specimens evaluated.

Analytical Study on the Flexural Strength of CFS Reinforced Concrete Beams under Service Loads (사용하중을 받는 RC보의 탄소섬유 휨 보강에 관한 해석적 연구)

  • Yoon, Tae-Ho;Kang, Kyung-Soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.8
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    • pp.3745-3751
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    • 2011
  • In this study flexural strength of damaged concrete beams reinforced by CFS is analysed. Nonlinear section analysis is used to include stress status of tension bars and compressive concrete under loads acting on the original member at the time of strengthening. Calculated flexural strength is compared with Sin-Hong formula which is frequently used in CFS reinforcement design. Nonlinear analysis with variation of the number of strengthening CFS, the ratio of tensile reinforcement, the ratio of section dimension shows that the flexural strength of CFS reinforced beams much depends on reinforcing stage. From the result of this analysis, the flexural strength of CFS reinforced concrete beam is reduced according to the magnitude of pre-loaded service loads.