• Title/Summary/Keyword: 연단

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Strength and Stress Distribution Behavior for the Connections of Corrugated Steel Plates (파형강판 이음부의 강도 및 응력분포특성에 관한 연구)

  • Hwang, Won Sup;Kang, Seung Pyo;Wi, Young Min
    • Journal of Korean Society of Steel Construction
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    • v.16 no.3 s.70
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    • pp.365-375
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    • 2004
  • This paper presents the numerical results in strength and stress distribution behavior for the connections of corrugated steel plates (CSP). The results obtained using the finite element method indicate that the CSP with =30mm of longitudinal edge lap, by the current standard specification, has very conservative values. The results also indicate the difference of strength behavior from the bolt arrangement. The strength behavior of standard corrugated type with staggered holes is only affected by circumferential edge lap, but the edge lap and bolthole spacing have an effect on the strength behavior for the deeply corrugated type with parallel holes. Based on these results, this paper examines the current specification of the connections for CSP.

Change of Strength of High-Strength Bolted Connection Depending on Standard and Over Bolt Hole (표준공과 과대공을 갖는 고장력볼트 접합부의 강도변화)

  • Yang, Seung-Hyun
    • Journal of Korean Society of Steel Construction
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    • v.24 no.5
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    • pp.605-612
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    • 2012
  • A tension member that has a high-strength bolt fastened to a standard bolt hole increases structural resistance but causes problems from workability or economic perspectives. In this research, a total of 28 samples that have standard and over bolt holes as the tension member's high-strength bolted connection were made and a tension test was conducted. The change of strength of the connection has been confirmed by comparing the tension load of standard and over bolt hole samples obtained from the test results with the design strength due to net section and end distance. Samples made with over bolt holes had a lighter tension load than that of samples made with standard bolt holes, exceeded the design strength of present design standards, and although decrease in strength was inevitable due to the over bolt hole, their safety was satisfactory.

An Experimental Study on Structural Behaviors of Double Shear Bolted Connections Fabricated with Ferritic Stainless Steel (STS430) (페라이트계 스테인리스강(STS430) 이면전단 볼트접합부의 구조거동에 관한 실험적 연구)

  • Kim, Tae Soo;Kim, Min Seong
    • Journal of Korean Society of Steel Construction
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    • v.25 no.5
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    • pp.463-474
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    • 2013
  • Many experimental and numerical researches for thin-walled carbon steel and austenitic stainless steel single shear bolted connections have been conducted and the modified design equations of ultimate strength were proposed. In this study, the tests of double shear bolted connections with bolt arrangements ($2{\times}1$, $2{\times}2$) and end distance parallel to the loading direction as main variables were performed. Specimens were planed with a constant dimension of edge distance perpendicular to the loading direction, bolt diameter, pitch and gauge like single shear bolted connections. The test results such as ultimate strength and fracture mode were compared with those of current design standards. Furthermore, modified block shear equations for double shear bolted connections were suggested.

A Study on the Pull-out Strength of Bond Type Anchors (부착식 앵커의 인발강도에 관한 연구)

  • Seo, Seong Yeon
    • Journal of Korean Society of Steel Construction
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    • v.30 no.2
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    • pp.105-114
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    • 2018
  • The use of post installed anchors with bond type has lately been increasing when it is necessary to repair, reinforce, or remodel structures. This method provides flexibility and simplicity for construction of structural members that require adhering or fixing. Meanwhile, strength evaluation of anchors with expansion type among post-installed anchors systems has nearly reached setting up stage like design code through continual experimental studies for the last ten years, but analyses or experimental studies on anchor system with bond type are not yet sufficient. Accordingly, the designers and builders of korea depend on foreign design codes since there are no exact domestic design code they could credit. In this study, the objectives are investigating the effects on pull-out strength of resin anchors embedded into plain concrete by pull-out experiment of resin anchors with variables such as anchor diameter, anchor interval, embedment depth and edge distance.

Dynamic Shear Strength of Stirrup-reinforced Cast-in Anchors by Seismic Qualification Tests (스터럽 보강 선설치 앵커의 지진모의실험에 의한 동적 전단 저항강도 평가)

  • Kim, Tae Hyung;Park, Yong Myung;Kang, Choong Hyun;Lee, Jong Han
    • Journal of Korean Society of Steel Construction
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    • v.30 no.2
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    • pp.67-76
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    • 2018
  • An experimental study was conducted to evaluate the breakout strength of stirrup-reinforced cast-in anchors under dynamic shear loadings. The shear loadings were applied in the manner specified in the ACI 355.2 and ETAG 001 for the seismic qualification tests. Test specimens were fabricated with M36 anchor (edge distance, 180mm) reinforced with D10 stirrups (spacing, 100mm). The specimens reached almost the breakout strength and thereafter fracture of anchor occurred. Additional tests with M42 anchor (edge distance, 160mm) reinforced with D6 bars (spacing, 100mm) were also conducted. The experimental results showed that the dynamic shear strength was not less than the static resistance. Based on the test results, it was shown that ACI 318 and ETAG 001 specifications estimate the breakout strength of stirrup-reinforced anchors conservatively as more reinforcement is provided.

An Experimental Study on the Shear Strength of Chemical Anchors Embedded into Non Cracking Plain Concrete (비균열 무근콘크리트에 매입된 케미컬 앵커의 전단내력에 관한 실험적 연구)

  • Seo, Seong-Yeon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.21 no.4
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    • pp.21-29
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    • 2017
  • The use of post installed anchors with adhesive type has lately been increasing when it is necessary to repair, reinforce, or remodel structures. This method provides flexibility and simplicity for construction of structural members that require adhering or fixing. Meanwhile, strength evaluation of anchors with expansion type among post installed anchors systems has nearly reached setting up stage like design code through continual experimental studies for the last ten years, but analyses or experimental studies on anchor system with adhesive type are not yet sufficient. Accordingly, the designers and builders of korea depend on foreign design codes since there are no exact domestic design code they could credit. In this study, the objectives are investigating the effects on adhesive strength of anchors embedded into plain concrete by shear experiments of anchors with variables such as edge distance, anchor interval, and load direction and supplying basic data for enactment of domestic design code.

Low flow projection considering actual evapotranspiration by climate change (기후변화에 따른 실제증발산을 고려한 갈수량 전망)

  • Kim, Eunji;Kang, Boosik;Sun, Hoyoung
    • Proceedings of the Korea Water Resources Association Conference
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    • 2020.06a
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    • pp.384-384
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    • 2020
  • 갈수량은 연간 355번째에 해당하는 일유량으로 연중 10일은 유지할 수 있는 유량을 의미한다. 갈수량은 하천유지유량을 결정하고 다목적댐의 이수안전도를 평가하는 기준으로 활용되는 지표로 활용되고 있으나 현재 기준으로는 과거사상에 초점을 맞추어 산정되고 있다. 본 연구에서는 기후변화에 따른 수문사상의 변화로 인한 미래 극한사상에 대비한 평가기준 마련을 위하여 CMIP5의 GCM 자료를 활용한 한강수계의 소양강댐의 실제증발산량을 추정하고, 이를 고려한 갈수량을 전망하고자 한다. 실제증발산의 경우 관측자료가 부재하므로 증발산 보완관계 가설 기반의 간접계산을 통해 추정하였으며, 잠재증발산량은 FAO Penman-Monteith 공식, 습윤증발산량은 Priestley-Taylor공식을 활용하여 산정하였다. 기준기간(1974-2000년) GCM 자료의 보정은 강우 및 증발산에 대하여 정상성 분위사상법을 적용하였으며, 우리나라의 홍수기 특성을 반영하기 위하여 홍수기(6~9월) 및 비홍수기(10~5월)로 구분하였다. 소양강댐 유역에 대한 연단위 원시 GCM의 경우, 연단위 강우와 실제증발산 각각 -20.0%, +17.3%의 오차율을 보였으나, 지역오차보정 후 각각 -1.2%, -0.2%로 개선되었다. 전망기간(2011-2100년)에 대해서는 비정상성 분위사상법을 적용하였으며, 지역오차보정 과정을 거친 강우 및 실제증발산 자료는 장기유출모형의 입력자료로 활용되었다. 실제증발산을 고려한 유출량을 산정하기 위해 IHACRES 모형을 활용하였으며, 갈수량은 모형으로부터 산정된 유출 시계열에 대한 lognormal 분포의 누적확률밀도함수의 3%에 해당하는 값으로 결정하였다. 전망결과는 근미래(Near future, 2011~2040년), 중미래(Midcentury future, 2041~2070년), 먼미래(Distance future, 2071~2100년)로 나누어 제시하였으며, 미래구간별 추세를 반영한 증감율을 제시하였다.

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Shear Strength Evaluation on Multiple High-Shear Ring Anchors Using Shear Strength Model of a Single High-Shear Ring Anchor (단일 고전단 링앵커의 전단강도 모델을 이용한 다수 고전단 링앵커의 전단강도 평가)

  • Kim, Mun-Gil;Chun, Sung-Chul;Kim, Young-Ho;Sim, Hye-Jung;Bae, Min-Seo
    • Journal of the Korea Concrete Institute
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    • v.28 no.4
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    • pp.463-471
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    • 2016
  • A shear strength model for the high-shear ring anchor consisting of a steel ring and a rod was developed based on the shear tests on single high-shear ring anchors. The shear strength was found to be proportional to $f_{ck}{^{0.75}}$ which is a similar characteristic to the strength of shear connectors used in composite structures. The effects of the compressive strength of concrete, edge distance, and embedment length of rod are included in the proposed model. Comparison with 22 tests shows that the average and the coefficient of variation of test-to-prediction ratios are 1.01 and 7.57%, respectively. Push tests on the specimens having four high-shear ring anchors at each face were conducted and the measured shear strengths were compared with the predictions by the proposed model. For the specimen with an edge distance of 100 mm, a splitting failure occurred and for the specimens with an edge distance of 150 mm, a failure mode mixed with splitting and bearing occurred, which were very similar to the failures of shear tests on single high-shear ring anchors. In case of a splitting failure, the overlap of failure surfaces could be prevented by providing the longitudinal spacing of 400 mm which is four times of the edge distance. In case of a bearing failure, the failure area is less than 150 mm from the center of the anchor and therefore the overlap of failure surfaces could be prevented by providing the longitudinal spacing of 200 mm. The average of the test-to-prediction ratios of Push tests is 98%, which means that the proposed mode can be applied to predict the shear strength of the multiple high-shear rings.

Elastic Buckling Analysis of Orthotropic Plate with Edge Stiffener (연단보강재가 설치된 직교이방성 평판의 좌굴해석)

  • Yoon, Soon Jong;Lee, Won Bok
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.14 no.2
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    • pp.281-290
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    • 1994
  • This paper presents the results of an analytical investigation pertaining to the compression behavior of axially loaded plates made from pultruded fiber reinforced plastic materials. Non-dimensionalized closed-form solutions have been developed for the prediction of the buckling load in the pultruded plates with edge stiffener. These solutions were based upon the classical theory of orthotropic plates and accounted for the e1astic restraints at the juncture of plate and stiffener. The effects of edge stiffener on the flange plate were investigated in order to clarify its usefulness for increasing flange local buckling load of the pultruded structural shapes.

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Accrate Vibration Analysis of Rhombic Plates with Various Combinations of Edge Conditions Considering Corner Stress Singularities (모서리 응력 특이도를 고려한 다양한 경계조건의 조합을 갖는 마름모꼴형 평판의 엄밀한 진동 해석)

  • 김주우;한봉구
    • Computational Structural Engineering
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    • v.11 no.4
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    • pp.275-286
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    • 1998
  • 본 논문은 고정, 단순, 또는 자유 연단 조건의 네 가지의 다른 조합을 갖는 마름모꼴형 평판의 자유진동 데이터를 처음으로 제시한 연구이다. 본 논문의 주된 관점은 마름모꼴 형 평판 둔각모서리의 휨응력의 특이도를 엄밀히 고려하여 해석하는 것이다. Ritz 방법을 이용하여 수직진동변위를 두 가지 적합 함수식으로 가정하였다. 힌지와 고정, 자유와 고정, 또한 힌지와 자유인 모서리 응력 특이도의 중대한 영향력이 이해될 수 있도록 충분히 큰 1650 둔각모서리를 갖는 마름모꼴형 평판에 대하여 엄밀한 무차원 진동수와 수직변동변위의 전형적인 등고선을 제시하였다.

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