• Title/Summary/Keyword: punching shear strength

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Punching Shear Strength and Behavior of CFT Column to RC Flat Plate connections (CFT기둥-RC 무량판 접합부의 펀칭전단강도 및 거동)

  • Lee, Cheol-Ho;Kim, Jin-Won;Lee, Seung-Dong;Ahn, Jae-Kwon
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2006.03a
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    • pp.168-179
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    • 2006
  • This paper summarizes full-scale test results on CFT column-to-flat plate connections subjected to gravity loading. CFT construction has gained wide acceptance in a relatively short time in domestic building construction practice due to its various structural and construction advantages. However, efficient details for CFT column to flat plate connections have not been proposed yet. Based on the strategies that maximize economical field construction, several connecting schemes were proposed and tested. Test results showed that the proposed connections can exhibit punching shear strength and connection stiffness exceeding those of R/C flat plate counterparts. A semi-analytical procedure is presented to model the behavior of CFT column-to-flat plate connections. The five parameters to model elastic to post-punching catenary action range are calibrated based on the limited test data of this study. The application of the proposed modeling procedure to progressive collapse prevention design is also illustrated.

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Hysteretic Behavior of Slab-Column Joint Using Bended Type Shear Reinforcement (절곡형 전단보강근을 사용한 슬래브-기둥 접합부의 이력 거동)

  • Lee, Hyun-Ho;Lee, Do-Bum;Lee, Li-Hyung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.10 no.3
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    • pp.211-218
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    • 2006
  • From the development of residential flat plate system, continuously bended shear reinforcement is developed for the prevention of punching shear. To know the punching shear capacity of developed shear reinforcement in slab-column joint, structural test is performed. The testing parameters are shear reinforcement types, such as no reinforcement, bended shear reinforcement, and head stud reinforcement. To verify the lateral capacity, cyclic load is applied under the constant vertical load condition. The results of tests are compared to as global displacement, slab-column joint strength. From the test results, the resisting capacity of developed shear reinforcement system has a good performance in the story drift ratio.

Punching Shear Strength of CFT Column to RC Flat Plate Connections Reinforced with Shearhead (전단머리 보강 CFT기둥-RC 무량판 접합부의 펀칭전단강도)

  • Kim, Jin-Won;Lee, Cheol-Ho
    • Journal of Korean Society of Steel Construction
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    • v.24 no.4
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    • pp.423-433
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    • 2012
  • This paper summarizes full-scale gravity-load test results on CFT column-to-RC flat plate connections reinforced with shearhead. CFT construction has many structural and constructional advantages over conventional steel and RC column construction and is gaining wide acceptance. Meanwhile the use of RC flat plate system in the basement and residential floors of tall buildings is often mandatory to reduce story height and enable rapid construction in domestic practice. Combining CFT column and flat plate floor is expected to result in further rapid construction. However, the issues related to connecting CFT column to RC flat plate have not been fully addressed yet. Several promising connecting schemes by using steel shearhead were proposed and tested in this study. Test results showed that the proposed connection can exhibit the punching shear strength higher than RC flat plate counterparts. An empirical formula that can reasonably predicts the punching shear strength of the proposed connection was also proposed.

Punching Shear Strength of Reinforced Concrete Slabs Subjected to Biaxial In-plane Tension (면내2축인장력을 받는 철근콘크리트슬래브의 펀칭전단강도)

  • Mo, Gui-Seok;Kim, Dae-Jung;Kim Woo
    • Magazine of the Korea Concrete Institute
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    • v.2 no.3
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    • pp.73-80
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    • 1990
  • This research program is directed at studying the behavior and the strength of reinforced concrete slabs sub¬jected to certain combination of punching shear and in-plane tension. Major variables to be investigated are the shear span to depth ratio of reinforced concrete slabs and the degree of the in-plane tensile force which is act¬ing tangent to the slabs. The experimental results are used for understanding of the degree of tbe interaction between the two loadings, and for developing a new practical design equation.

Study on the Utilization of Steel Fiber Reinforced Concrete for Efficient Structural Behavior in Slab System (슬래브의 효율적인 구조 거동을 위한 강섬유보강 콘크리트의 부분적 활용에 관한 실험적 연구)

  • 윤영수;데니스미첼;최응규;박성균
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.04b
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    • pp.469-474
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    • 1998
  • To overcome the common deficiencies found in two-way slabs, such as excessive cracking around columns, excessive deflections and low punching shear strength, it was proposed to investigate the strategic use of steel fiber-reinforced concrete. Providing fiber-reinforced concrete results in an increase in the punching shear resistance, a significant increase in the ductility, greater post-cracking stiffness and better crack control.

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Proposed Detailing of Reinforcement to Enhance the Structural Performance in Two-way Slab System (이방향 슬래브의 구조성능 향상을 위한 배근상세의 제안)

  • ;Denis Mitchell
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.04a
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    • pp.379-384
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    • 1998
  • To overcome the common deficiencies found in such two-way slabs, such as excessive cracking around columns, excessive deflections and low punching shear strength, it was proposed to investigate the strategic reinforcing steel distribution detailings. Concentration of the top mat of flexural reinforcement result in a higher punching shear resistance, higher post cracking stiffness, a more uniform distribution of strains in the top bars and smaller cracks at all levels of loading.

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Experimental Study about Punching Shear Strength of Biaxial Hollow slab with Donut type Hollow Sphere (도넛형 중공형성체를 사용한 중공슬래브의 뚫림 전단 성능에 관한 실험적 연구)

  • Chung, Joo-Hong;Choi, Hyun-Ki;Lee, Seung-Chang;Choi, Chang-Sik
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.59-60
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    • 2010
  • This paper presents the flexural capacities of biaxial hollow slab with donut type hollow sphere. To verify the punching shear capacities of this biaxial hollow slab, punching shear tests were performed. The test parameter was the areas of critical section which were determined by the number of hollow spheres in critical section.

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The Effect of Anchorage of Reinforcement in Slab-Column Connection (슬래브-기둥 접합부에서 전단보강체에 정창성능에 따른 영향)

  • Choi, Huyn-Ki;Kim, Jun-Seo;Lee, Moon-Sung;Choi, Chang-Sik
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.185-188
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    • 2008
  • Flat plate system has structural weakness such as punching shear. Punching shear resistance can be increase by using a lager column section and effective depth, higer concrete compressive strength, and more flexural reinforcement ratio. But using a shear reinforcement is most economical, enable, workable solution in flat plate. The slab with thickness smaller than 250mm can not perform effectively due to insufficient development length of shear reinforcement in the slab. In case of proposed reinforcements, since the shear reinforcements were installed between the top bar and the bottom bar, shear elements generated slip failure before they reached yield. strength. effect of anchorage strength were effective anchorage length, concrete strength, diameter of shear element and anchorage detail. considering effect of slab thickness and concrete strength, formula of K factor propose in thin flat plate slab. by considering effect of anchorage length and concrete strength, strength of shear reinforcement will be computed correctly in thin flat plate slab.

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Evaluation of Punching Shear for Flat Plates Using GFRP Plate Shear Reinforcement (GFRP 판을 전단보강재로 사용한 플랫 플레이트의 뚫림전단 성능 평가)

  • Lee, Young Hak;Kim, Min Sook;Hwang, Seung Yeon;Choi, Jinwoong;Kim, Heecheul
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.27 no.5
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    • pp.413-420
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    • 2014
  • The purpose of this study is to experimentally investigate the shear behavior of flat plate that reinforced by embedded GFRP(glass fiber reinforced polymer) plate with openings. Shape of the GFRP shear reinforcement is a plate with several openings to ensure perfect integration with concrete. The test was performed on 7 specimens to check shear strength of flat plate that reinforced by GFRP plate. The parameters include the spacing of the shear reinforcement and amount of the shear reinforcement. The result of test showed that when amount of shear reinforcement was increased, shear strength improved. The result of test showed that maximum shear strength was confirmed when spacing of shear reinforcement was 0.3d. The calculation of the shear strength of reinforced flat plate with GFRP plate based on the KCI was compared with the test results.

Theoretical Assessment of Limit Strengthening Ratio of Bridge Deck Based on the Failure Characteristic (교량 바닥판의 파괴형태를 고려한 임계보강재비의 이론적 산정)

  • 심종성;오홍섭;유재명
    • Journal of the Korea Concrete Institute
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    • v.14 no.1
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    • pp.110-117
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    • 2002
  • In a strengthened bridge deck which received increased service loads, failure patterns of bridge deck vary depending on deck thickness, compressive strength of concrete, yielding strength of reinforcement, reinforcement ratio and additional strengthening ratio. General failure pattern that is most commonly reported as punching shear failure after the main rebar yields, followed by yielding of distributing rebar. In this paper, by Proposing a limit to the amount of strengthening material, a brittle failure can be prevented and a ductile failure mode similar to that developed in unstrengthened deck is derived. In order to calculated the limit strengthening ratio, the yield line theory and previously proposed plastic punching shear model have been used