• Title/Summary/Keyword: 구조강도평가

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The Development on the Buckling Strength Estimation Formula of Plate Members in Consideration of Inplane Tension(I) (면내인장력을 고려한 판부재의 좌굴강도 평가식 개발 (I))

  • Ham, Juh H.;Kim, Ul N.;Chung, Yun S.
    • Journal of the Society of Naval Architects of Korea
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    • v.33 no.2
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    • pp.111-118
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    • 1996
  • Ship structure basically consists of plate members and it's overall strength depends an the stiffness and strength of each plate member. The buckling strength of plate is one of the most important design criteria when we investigate the structural intergraty. Therefore, it is necessary to surly reasonable buckling formula in order to carry out a more efficient and reliable design. In the present study, the buckling design formula of plate panels under combined loads(inplane compression, tension and shear) is obtained on the theoretical solution or reference paper. This formula is compared with the existing theoretical solution, other author's formula[1], design codes of LR and results which are obtained by numerical analysis. It has a good correlation with numerical analysis results or theoretical ones. When we evaluate buckling strength of plate panels, this formula can be presented with reasonable accuracy.

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Two-way Shear Strength Evaluation of Transfer Slab-Column Connections Through Nonlinear FE Analysis (비선형유한요소해석을 통한 전이슬래브-기둥 접합부의 2면 전단강도 평가)

  • Jeong, Seong-Hun;Kang, Su-Min
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.31 no.6
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    • pp.315-329
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    • 2018
  • Recently, RC transfer slab systems have been used widely to construct high-rise wall-type apartments for securing parking space or public space. However, it is problem that the design method and structural performance evaluation method developed for thin RC flat slab are still used in the design of the transfer slab whose thickness is very thick and therefore structural behavior is expected to be different from RC flat slab. Thus, for the rational design of the transfer slab, the ultimate shear behavior of the RC transfer slab system is required to be analyzed properly. Accordingly, in the present study, the two-way shear behavior of the transfer slab was analyzed using nonlinear FEM according to various design parameters such as thickness of the transfer slab, strength of concrete, shear span ratio, and reinforcement ratio. In addition, the two-way shear strength evaluations of RC transfer slab by the existing evaluation methods were verified by comparing those with the results of nonlinear FEM analysis.

Comparative Study on Test Methods for Mechanical Properties of Structural Adhesives Used in FRP Strengthening (구조보강용 FRP 함침·접착수지의 역학적 특성 분석을 위한 시험방법 비교 연구)

  • You, Young Chan;Choi, Ki Sun;Kim, Keung Hwan
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.12 no.2
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    • pp.103-112
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    • 2008
  • Pull-off test is generally used to evaluate bond strength of FRP composite with concrete at job site. However, some damages on FRP composites can not be avoided during pull-off test and moreover test range of pull-off strength is limited by maximum tensile strength of concrete. Accordingly, it is required to set-up a test method that can evaluate mechanical properties of structural adhesive indirectly prior to pull-off test. In this study, the standard test methods for structural adhesive which can simply evaluate mechanical performance of adhesive were suggested through comparative experiments from each different standard in various countries. Particularly, gluing thickness of adhesive in tensile lap-shear tests, the section dimension of compression and bending test specimens become unified, and standard test specimen size is achieved by test results.

A Study on the Safety Evaluation of Structural Members based on Strain Sensors (변형률 센서 기반 구조부재의 안전성 평가에 관한 기초 연구)

  • Lee, Hong-Min;Oh, Byung-Kwan;Park, Hyo-Seon
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2010.04a
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    • pp.700-703
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    • 2010
  • 일반적으로 구조부재의 안전성 평가는 계측된 센서의 변형률로부터 부재의 최대응력 또는 부재력 수준을 결정하고 설계기준에 의한 부재의 허용응력 또는 설계 강도와의 비교에 의해서 이루어진다. 그러나 이러한 설계기준은 건물의 설계단계에서 미리 가정된 하중 및 부재의 강도에 대한 여러 확률분포 또는 안전율을 반영하여 작성된 것으로 실질적으로 센서로부터 측정한 데이터를 직접 설계기준에 반영하는 것은 합리적이지 못하다. 본 연구에서는 실제 센서로부터 측정되는 변형률을 이용하여 합리적으로 구조부재의 안전성 평가를 수행하기 위한 방법을 모색하고자 한다. 설계기준을 고려한 변형률 제한치, 저감계수가 도입되었으며 이에 추가적으로 센서와 관련한 계수를 도입하여 구조부재의 안전성 평가를 위한 방향을 제시한다.

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An Experimental Study on Intensity property of High Strength Concrete Using Transparent Joint Separation Test Body (투명 접합분리 몰드를 사용한 고강도 콘크리트의 강도특성에 관한연구)

  • Ki, Jun-Do;Park, Hyun;Kim, Kwang-Ki;Paik, Min-Su;Lee, Young-Do;Jung, Sang-Jin
    • Proceedings of the Korea Concrete Institute Conference
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    • 2009.05a
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    • pp.411-412
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    • 2009
  • The techniques of testing and controlling intensity of structural concrete involve many problems and difficulties on the construction site. Hence this study aims at evaluating intensity of structural concrete in order to verify on-site application and structural efficiency assessment using joint separation test body.

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Studies on the evaluation method of structural concrete strength using joint separation test body (접합분리 시험체를 사용한 구조체 콘크리트 강도 평가에 관한 실험적 연구)

  • Kim, Seong-Deok;Lee, Seon-Ho;Kim, Kwang-Ki;Jung, Kwang-Sik;Lim, Nam-Ki;Jung, Sang-Jin
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.04a
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    • pp.993-996
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    • 2008
  • It has been reported that destruction test by core collection is the most reliable of the structural concrete strength in present building construction field. But it causes low efficiency by damage and cutting in structure due to the core collection. It also has some problems in repairing. Additionally in case of strength test with management specimen, different environment compared to the structure environment cause problems about estimation precise structure strength. Therefore, it is required to develop structure direct strength test that has test values and credibility above the ones obtained by core specimen collection strength test and seasonal specimen test to suggest a reasonable and practical management method of structural concrete.

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Evaluation of Flexural Strength for Normal and High Strength Concrete with Hooked Steel Fibers (갈고리형 강섬유를 혼입한 보통 및 고강도 콘크리트의 휨강도 평가)

  • Oh, Young-Hun
    • Journal of the Korea Concrete Institute
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    • v.20 no.4
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    • pp.531-539
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    • 2008
  • The purpose of this study is to investigate the mechanical properties of high strength concretes reinforced with hooked steel fiber. For this purpose, total 36 specimens whose variables are concrete compressive strength, steel fiber aspect ratio, and steel fiber volume contents, are made and tested. From the test results including previous research work, flexural performance of steel fiber reinforced high strength concrete is evaluated in terms of flexural strength and toughness index. Flexural behavior of steel fiber reinforced high strength concrete is enhanced with respect to the fiber volume content, the aspect ratio, and concrete compressive strength. More efforts are devoted to evaluate quantitatively between the flexural strength and the structural parameters such as the fiber volume content, the aspect ratio, and concrete compressive strength.

Residual Stress & Fatigue strenght in Welding Ship Structure (선박 용접구조의 잔류응력과 피로강도)

  • 김화수
    • Journal of Welding and Joining
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    • v.15 no.3
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    • pp.12-20
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    • 1997
  • 구조의 용접접합부에는 재료의 항복응력 크기의 용접잔류응력이 발생되고, 이 잔류응력 상태에서는 응력비(최소응력/최대응력)의 영향이 거의 없다는 것이 일정 진폭 하중조건의 피로실험결과로부터 알려져 있다. 이와 관련하여, 용접구조의 설계 단계에서는 초기 용접잔류응력이 그래도 잔류한 소형실험편의 일정진폭하중 상태의 피로실험 결과로부터 도출된 피로설계선도(S-N 선도)를 이용, 변동하중에 의한 응력 진폭의 밀도분포만으로 일생동안의 누적피해도를 구해 피로강도를 평가하는 것이 일 반적이다. 지금까지는 선박용접구조의 경우도 이러한 개념으로 피로강도 평가를 수행 하였으나, 일반적인 육상 또는 해상 용접구조물과는 달리, 화물의 적재 등의 정하중 이력에 의한 응력변동폭은 피로를 유발하는 파랑 응력변동폭보다 상당히 크다. 그리 고, 정하중에 의해 용접접합부에 인장응력을 발생시키는 하중이력을 받을 경우, 초기 용접잔류 응력은 상당히 저하될 것으로 생각된다. 본 연구에서는 인장응력을 유발하는 정하중 이력에 의해 저하된 용접잔류응력분포와 이러한 잔류응력분포를 가진 선측 종늑골 용접접합부의 피로강도를 검토한다.

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Applicability of Impact-Echo Method for Assessment of Residual Strength of Fire-Damaged Concrete (화해된 콘크리트의 잔존 강도 평가에 있어서 충격-반향 기법의 적용성)

  • Shin, Sung-Woo;Kim, Seung-Yong;Kim, Jeong-Su
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.17 no.5
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    • pp.105-112
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    • 2013
  • In this study, the applicability of impact-echo method for assessment of residual strength of fire-damaged concrete is investigated. A series of standard fire test is performed to obtain fire-damaged concrete specimens. Impact-echo tests are executed on the specimens and the responses are analyzed. Compressive strengths of the fire-damaged concrete are evaluated and correlated with the ultrasonic wave velocities determined from the impact-echo responses. The effectiveness of impact-echo based ultrasonic wave velocity measurement for assessment of residual strength of fire-damaged concrete is discussed.

A Study on Improvement of Structural Strength Evaluation Methods for Tank of Tank Car used for Carrying Hazard Materials (위험물 수송 철도차량 탱크의 구조강도 평가방법 개선연구)

  • Lim, Chung-Hwan;Goo, Byung-Choon
    • Fire Science and Engineering
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    • v.22 no.3
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    • pp.239-245
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    • 2008
  • In this study, we researched about characteristics of many kinds of tank cars for carrying hazard materials and performed structural strength evaluation using finite element analysis for tank of asphalt tank car to suggest the efficient analysis method that can develop accuracy regarding to characteristics of tank cars. For this, we analyzed the asphalt tank refer to JIS E 7102 (Design Method for Tanks of Tank Cars). As results, we could show that the maximum stress is applied at the area supported by saddle and the maximum stress is under a criterion suggested from JIS E 7102. Therefore we verified that this asphalt tank car had enough structural strength.