• Title/Summary/Keyword: 휨 시험체

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Strength Performance Evaluation of Deck Using Reinforced Plastic Connector (강화플라스틱 연결구를 이용한 데크의 내력 성능평가)

  • Song, Yo-Jin;Jung, Hong-Ju;Lee, Dong-Heub;Kim, Kyung-Dae;Hong, Soon-Il
    • Journal of the Korean Wood Science and Technology
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    • v.41 no.1
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    • pp.12-18
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    • 2013
  • Existing wood decks brings out negligent accident because fastener can be pulled-out by cyclic load of pedestrians. When deck and joist are connected, it also causes the problems, which are cracking of wood decks and rapid decay by material of fastener. In this study, strength property of deck unit using reinforced plastic connector made by domestic A company was evaluated. Southern yellow pine (Pinus palustris Miller) were used for deck material. Bending strength of deck units were implemented for fastener type and joist spacing (400, 600 mm). In the result, carbon steel screw into reinforced plastic connector was the best in average bending strength(Joist spacing : 400, 600 mm). In the result of bending strength for joist-width (40, 50, 70, 80 mm), the average maximum bending strength was measured when the joist spacing was 40 mm.

Physical and Mechanical Properties of Magnesium Oxide Matrix depending on Addition Ratio of Magnesium Chloride (염화마그네슘 첨가율에 따른 산화마그네슘 경화체의 물리 및 역학적 특성)

  • Kim, Heon-Tae;Jung, Byeong-Yeol;Lee, Sang-Soo;Song, Ha-Young
    • Journal of the Korea Institute of Building Construction
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    • v.14 no.4
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    • pp.308-313
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    • 2014
  • Recently, for longevity of resident building, the main trend is that the change of the inside space organization of resident building from wall construction to rhamen construction, which resulted in increase in use of lightweight composite panel. Thus, in this study, authors analyzed the engineering property of oxide of magnesium depending on the magnesium chloride addition ratio. The results of this research is expected to contribute on providing a fundamental material for the surface materials of lightweight composite panel. As the result of the experiment, as fluidity increased, air content decreased and initial set and final set as the magnesium chloride addition ratio increase. In the aspect of flexural strength and compressive strength, the test specimen showed the highest strength at 40% of the magnesium chloride addition ratio. At 20% of the magnesium chloride addition ratio, the test specimen showed the lowest water absorption rate. As the magnesium chloride addition ratio increases, the expansibility tends to increase as well in the aspect of shrinkage strain. After observing microstructure, we can see hydration products in the form of needle. It appeared high flexural strength because the hydration products have mineral fibrous tissue shape, which also contribute to the cause of the expansibility.

Experimental Study on Flexural Capacity of Circular Concrete Beam Confined by Carbon Fiber Tubes (탄소섬유관으로 구속된 무근 원형 보의 휨성능에 관한 실험적 연구)

  • Lee, Kyoung-Hun;Hong, Won-Kee;Lee, Young-Hak;Kim, Hee-Cheul
    • Journal of the Earthquake Engineering Society of Korea
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    • v.11 no.1 s.53
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    • pp.37-43
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    • 2007
  • Experiments for circular unreinforced concrete beams confined by carbon fiber tubes (CFT) made of carbon fiber sheets were performed. Selected test parameter was thickness of carbon fiber tube: 1.5mm (3 layers), 2.0mm (4 layers), 2.5mm (5 layers), and 3.0mm (6 layers). Based on the test results, an equation for estimating moment capacity of the circular beams confined by carbon fiber tubes was proposed. Comparison results showed good agreement up to 2.5mm (5 sheets) of the CFT thickness.

Effect of T-Plate Anchorage on the Flexural Behavior of Reinforced Concrete Columns Strengthened with Wire Rope Units (와이어로프로 보강된 철근콘크리트 기둥의 휨 거동에 대한 강판 정착의 영향)

  • Sim, Jae-Il;Yang, Keun-Hyeok;Byun, Hang-Yong
    • Proceedings of the Korea Concrete Institute Conference
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    • 2009.05a
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    • pp.493-494
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    • 2009
  • Two strengthened columns and an unstrengthened control column were tested to failure under cyclic lateral load combined with a constant axial load to effect of anchorage of T-shaped steel plate in the strengthened column using wire rope units. Main variables considered were anchorage method of T-shaped steel plate. Tested columns were compared with those of conventionally tied columns tested by research of before. Test results showed that lateral load capacity and the displacement ductility ratio of anchorage of T-shaped steel plate in the strengthened column increased 40% and 130% than unstrengthened column, respectively. In particular, at the same effective lateral reinforcement index, a much ductility ratio was observed in the strengthened columns than in the tied columns.

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Development of Polymer-Concrete Composite(I) - Physical Properties of Polymer-Cement Concrete Composites - (폴리머-콘크리트 복합재료 개발(I) - 폴리머-시멘트 콘크리트의 물성 -)

  • Hwang, Eui-Hwan;Kil, Deog-Soo;Oh, In-Seok
    • Applied Chemistry for Engineering
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    • v.8 no.6
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    • pp.979-984
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    • 1997
  • Test specimens of polymer-cement concrete composites were prepared using styrene-butadiene rubber(SBR) latex, ethylenevinyl acetate(EVA) and polyacrylic ester(PAE) emulsions as polymer dispersions in cement modified system at constant slump($10{\pm}0.5cm$), then compressive and flexural strengths water absorption, pore size distribution, and microstructures were investigated. Compressive and flexural strengths of these composites were remarkably improved with an increase of polymer-cement ratio. These composites had a desirable pore size distribution against frost damage due to a small capillary pore volume. Continuous polymer film was able to form in higher than 15% of polymer cement ratio.

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An Evaluation of Lap Splice Length of Epoxy Coated Reinforcements Using Beam-End Test (보-단부 시험을 이용한 에폭시 도막 철근의 겹침 이음길이 평가)

  • Kim, Jee-Sang;Kang, Won Hyeak
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.8 no.2
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    • pp.175-182
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    • 2020
  • The application of epoxy coated reinforcements is increased as a means to prevent a corrosion of reinforcements embedded in reinforced concrete structures, However, epoxy coating may reduce the bond capacity between concrete and reinforcement, which results a longer development length and lap splice length. This paper aims to the possibility of modification in lap splice length from reduction of basic development length which was confirmed using a direct pull out test. Total 36 beam specimens were tested to compare the lap splice properties of normal and epoxy coated reinforcements with beam-end test for various lap lengths and diameters of reinforcements. According to the results on failure modes, deformations, and crack widths of this experiments, the modification factor of 1.2 should be used, though the direct bond capacity is assured through direct pull out test.

Experimental Study on Dynamic Characteristics of Vibration-Controlled Concrete Beam (제진 콘크리트 보의 동적특성에 관한 실험적 연구)

  • 정영수;최우성;이대형
    • Magazine of the Korea Concrete Institute
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    • v.9 no.6
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    • pp.185-193
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    • 1997
  • 본 연구는 각종 제진재료를 이용하여 진동을 억제할 수 있는 콘크리트를 개발하여 각종 건설공사에서 흔히 발생할 수 있는 진동공해문제를 억제하고자 하며 아울러 폐기물의 재활용차원에서 폐자재를 이용하여 유용한 제진콘크리트를 개발하고자 하는데 그 목적이 있다. 우선, 제진재료를 이용한 압축강도 (200kg/$\textrm{cm}^2$)이상의 콘크리트 배합비를 찾기 위하여 24배치의 예비실험을 수행하였으며, 선정된 적정배합비에 따른 제진재료를 이용한9개의 진동시험체보를 제작하여 보의 구조적 및 재료적 동적특성 즉 1차 공명진동수와 동적 휨강성 및 감쇠비를 측정하여 제진효과를 조사하였다. 그리고 압축강도에 의한 각 시험체의 균열모멘트를 추정하여 재하하중과 균열모멘트비(M/Mcr)에 따른 하중단계별 동적특성값을 살펴보았다. 제진재료로서는 라텍스(Latex), 고무분말(Rubber Powder)그리고 플라스틱 레진( Plastic Resin)등을 사용하였고, 재료적, 구조적 진동감쇠효과를 파악하고자 KS F2437규정과 진동파의 속도법을 사용하였으며, 감쇠비 측정은 Frequency Spectrum 곡선에 대한 Polynomial Curvefitting 방법과 기하학적 해석방법을 이용하여 각각의 결과를 비교.분석하였다.

Carbonation Evaluation After CO2 Curing of Concrete Bricks Using Industrial by-products (산업부산물을 사용한 콘크리트 벽돌의 CO2 양생 후 탄산화 평가 )

  • Hoon Moon;Namkon Lee;Jung-Jun Park;Gum-Sung Ryu;Gi-Joon Park;Indong Jang
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.11 no.4
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    • pp.373-380
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    • 2023
  • This study investigated the carbonation of concrete brick cured in a CO2 environment for the utilization of CO2 captured in power plants. Concrete brick specimens were produced with electric arc furnace reducing slag (ERS) and electric arc furnace oxidizing slag (EOS), and cured for 3 days in a CO2 chamber with a concentration of 20 % or in a constant temperature and humidity chamber. The weight change, compressive strength, flexural strength and carbonation depth of concrete bricks were measured. From the results, it was found that when subjected to CO2 curing, CO2 was absorbed at the level of 2.4 % of the weight of the specimen. The specimen incorporating ERS showed the highest carbonation depth, and satisfied KS F4004 standards for the concrete brick. Therefore, it is expected that the captured CO2 can be utilized in the CO2 curing process of concrete brick.

The Evaluation of flexure performance of SCP modules for LNG outer tank (LNG 외조탱크 적용을 위한 SCP 모듈의 휨성능 평가)

  • Park, Jung-Jun;Park, Gi-Joon;Kim, Sung-Wook;Kim, Eon;Shin, Dongkyu
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.1
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    • pp.447-455
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    • 2019
  • When constructing LNG storage structures using the cast-in-place method in extreme areas, the construction cost and time may be increased due to the poor working environments and conditions. Therefore, demand for modular energy storage tanks is increasing. In this study, we propose using an SCP module as an alternative for lighter-weight LNG storage tanks. The purpose of this study is to evaluate the feasibility of LNG storage outer tanks by performing bending tests on the thickness of composite steel plate concrete under field conditions. The loads on specimens with thicknesses of 100 mm and 200 mm were linearly increased to the design final loads of 413 kN and 822 kN, respectively. The slope was rapidly changed, and fracture occurred. The two test conditions showed linear behavior until the steel plate yielded, and after an extreme load behavior, sudden yielding of the steel plate yield occurred in the SCP bending test according to the INCA guidelines. The results satisfied the design flexural load and showed the possibility of using the specimens in a modular LNG outer tank. However, it is necessary to evaluate the structural performance of the SCP by performing compression and shear tests in future research.

Reinforcement Effect of Reinforced Concrete Beams Strengthened with Grid-type Carbon Fiber Plastics (격자형 탄소섬유로 보강한 R/C보의 보강효과)

  • Jo, Byung-Wan;Tae, Ghi-Ho;Kwon, Oh-Hyuk
    • Journal of the Korea Concrete Institute
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    • v.15 no.3
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    • pp.377-385
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    • 2003
  • Flexural characteristics of the R.C beams strengthened with newly-developed grid-type carbon fiber plastics(CFRP-GRIDS) were investigated. The tests were conducted under the four-points load to the failure to investigate the strengthening effects of CFRP-GRIDS on the beams. Results showed that initial cracks appeared in the boundary layers of fibers embedded in the newly-placed mortar concrete slowly progressed to the direction of supports and showed fracture of fiber plastics and brittle failure of concrete in compression in sequence after the yielding of steel reinforcement. Accordingly, the appropriate area of Grid-type carbon-fiber plastics in the strengthening design of deteriorated RC structures should be limited and given based on the ultimate strength design method to avoid the brittle failure of concrete structures.