• Title/Summary/Keyword: main reinforcement

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Inelastic Behavior of High Strength Reinforced Concrete Beam-Column Joint (고강도 철근 및 고강도 콘크리트를 사용한 보-기둥 접합의 비선형 거동)

  • 이정한;조중현;유영찬;이원호;정헌수
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.04a
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    • pp.547-552
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    • 1999
  • The purpose of this study is to make a contribution to the construction of 40∼60 story R/C high rise building by developing the reinforcing details which can improve the seismic performance of high-strength (f'c=700㎏/㎠, fy=4000, 8000㎏/㎠) R/C beam-column joints. The reinforcing details which can make beam plastic hinging zones moved and spreaded from the column face is proposed to insure the ductile behavior of high-strength RC beam-column joints. The intermediate reinforcement which is vertically anchored by interlinking each intermediate reinforcements is proposed and tested to examine the mechanical performance of proposed details. Main variables are the shape of the intermediate reinforcements and yield strength of rebars. From the test results, the newly proposed intermediate reinforcement details can move and spread the beam plastic hinging zone about 1.0d from the column face.

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Shear Behavior Characteristics of Joint according to Strain-Hardening Cement Composite Types (시멘트 복합체 종류에 따른 접합부의 전단거동특성)

  • Nam, Sang-Hyun;Jeon, Esther;Yun, Hyun-Do;Choi, Ki-Sun;You, Young-Chan;Kim, Keung-Hwan
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.27-28
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    • 2010
  • This paper discusses behavior of Joint with strain hardening cement composites(SHCC). The main variables considered include the type of cement composites(mortar, SHCC with hybrid fiber) and shape and space of reinforcement. As the result of the tests, for the same reinforcement detail, SHCC specimen showed better overall behavior(stress, ductile, multiple cracking) than mortar specimen.

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Performance Evaluation of Confined Concrete According to Cross Sectional Shape (단면형상에 따른 횡구속 콘크리트의 성능 평가)

  • Kim, Young-Sik;Kim, Min-Jun;Kim, Sang-Woo;Baek, Seung-Cheol;Lee, Jung-Yoon;Kim, Kil-Hee
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.77-78
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    • 2010
  • This study investigated the influence of concrete compressive strength for the lateral confinement of high-strength spiral reinforcement. The main test parameters were the compressive strength of concrete, the yield strength of spiral reinforcement, and cross sectional shape. A total of 48 cylindrical test specimens with circularand rectangular sections were cast and tested under monotonic concentric compression.

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Shear Strength of Prestressed Steel Fiber Concrete I-Beams

  • Tadepalli, Padmanabha Rao;Dhonde, Hemant B.;Mo, Y.L.;Hsu, Thomas T.C.
    • International Journal of Concrete Structures and Materials
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    • v.9 no.3
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    • pp.267-281
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    • 2015
  • Six full-scale prestressed concrete (PC) I-beams with steel fibers were tested to failure in this work. Beams were cast without any traditional transverse steel reinforcement. The main objective of the study was to determine the effects of two variables-the shear-span-to-depth ratio and steel fiber dosage, on the web-shear and flexural-shear modes of beam failure. The beams were subjected to concentrated vertical loads up to their maximum shear or moment capacity using four hydraulic actuators in load and displacement control mode. During the load tests, vertical deflections and displacements at several critical points on the web in the end zone of the beams were measured. From the load tests, it was observed that the shear capacities of the beams increased significantly due to the addition of steel fibers in concrete. Complete replacement of traditional shear reinforcement with steel fibers also increased the ductility and energy dissipation capacity of the PC I-beams.

Vibration reduction of the Engine Casing "B" deck in the handymax vessel (Handymax 급 PC 선 Engine Casing "B" deck 의 진동 저감)

  • Seo, Myung-Gab;Jeong, Tae-Seok;Seok, Ho-Il
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2009.04a
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    • pp.498-503
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    • 2009
  • This paper presents the vibration problem of the Engine Casing (E/C) "B" deck in the handymax vessel and describes a method to avoid resonance. The first ship of the series did not have any vibration issue on the "B" deck. However, resonance condition occurred when additional machine was installed to the following vessels. To understand the dynamic characteristics of the deck, the normal mode analysis and impact test have been performed. Within the normal operating range of the vessel, the $1^{st}$ natural frequency of the E/C "B" deck is close to the main engine's $6^{th}$ order. Based on these analysis, a reinforcement on the deck was suggested and it proved to be effective. Since actual impact test after the reinforcement also confirmed the resonance avoidance.

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Evaluation Repair Performance of Damaged R/C Beams due to Reinforcement Corrosion (철근 부식에 의해 단면이 손상된 R.C보의 보수성능평가)

  • Jeong, Sang-In;Hong, Geon-Ho;Shin, Yeong-Soo;Chung, Lan
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.04a
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    • pp.733-738
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    • 2000
  • This paper was aimed to evaluate the structural performance of flexural members repaired by polymer cement and epoxy mortar at soffit. Main test variables were repair materials, ratio of reinforcement and additional reinforcing bars. Test results shows that the repaired beams could change flexural capacity by materials and additional reinforcing bars. In polymer cement, the section repaired can carry same load, cracking moment and the flexural stiffness of the monolithic beams with same size. In epoxy mortar, all data were greater than the shotcrete. However, note that epoxy mortar may conduct member into brittle failure mode.

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Fracture Behavior of Reinforced Concrete Beams Repaired by Latex-Modified Concrete (LMC로 보강된 철근콘크리트 보의 파괴거동)

  • 김성환;정원경;김기헌;김동호;윤경구
    • Proceedings of the Korea Concrete Institute Conference
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    • 2003.05a
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    • pp.475-480
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    • 2003
  • Latex modification of concrete provides the material with higher flexural strength. This increase in flexural strength can attribute to the crack-arresting action of polymer in concrete, and also to the bonding they provide between the matrix and aggregates. This experimental study presents the fracture behavior of 12 flexural reinforced concrete beams repaired or strengthened by latex-modified concrete with the main experimental variables such as overlay thickness, strength thickness, and shear reinforcement. The results are as follow: All beam specimens having shear reinforcement were failed by delamination rupture at concrete interface at about 80% of ultimate loading after flexural cracking. All specimens overlayed and strengthened by latex-modified concrete (LMC) showed higher ultimate flexural strength than OPC control specimen, but lower than LMC control specimen. This increase in flexural strength could attribute to the high bonding they provide between the matrix and aggregates. All specimens except two shear unreinforced showed quite similar and consistent displacement behavior. The effect of overlay and strength thickness on the load-displacement relationship were a small at this study.

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Physical properties of Reinforced soil Mixture powder (보강혼합토분의 물리적 특성)

  • 이상호
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.42 no.5
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    • pp.125-132
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    • 2000
  • This study was performed to evaluate the physical properties of reinforced soil mixture powder. Soil sample was prepared by passing into the standard sieve of No. 200 and reinforcement materials were calcium carbonate, quicklime and portland cement. Fineness, setting time, and compressive strength test for reinforced soil mixture powder were performed and analyzed to investigate their physical properties. The main results were summarized as follow. The compressive strength of soil mixture powder itself and most reinforced was reinforced according to increasing in the mixture rate of reinforcement and the rate of increase was remarkably higher in the cement reinforced soil moisture powder. It was appeared that the early compressive strength is considering higher in the cement reinforced soil moisture powder with 2% of moisture rate of accelerator.

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Tension Stiffening Effect for Reinforced Concrete Members (철근 콘크리트 부재의 인장강성 효과에 관한 연구)

  • 이봉학;윤경구;홍창우
    • Journal of the Korea Concrete Institute
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    • v.11 no.4
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    • pp.83-93
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    • 1999
  • This paper presents tension stiffening effect of Reinforced concrete members obtained from experimental results on direct tension and bending. From the direct tension test program, crack patterns were investigated with tension softening behaviors of concrete. Tension stiffening effects and losses of strain energy were, also, analyzed from the load-deflection curve with the main experimental variables such as concrete strength, yielding stress and reinforcement ratio of rebar. Tension stiffening effect of RC members increase linearly until the first crack initiate, decrease inversely with number of cracks, and then decrease rapidly when splitting cracks are happened. The tension stiffening effect is shown to be more important at the member of lower reinforcement than that of higher. Therefore, it necessitates to consider the tension stiffening effects at a nonlinear analysis. From the above analysis, a tension stiffening model of concrete is proposed and verified by applying it to bending members. From the numerical analysis by finite element approach, it is shown that the proposed model evaluates a little higher in analyzing at nonlinear region of high strength concrete, but, perform satisfactorily in general.

Influence of viscous phenomena on steel-concrete composite beams with normal or high performance slab

  • Fragiacomo, M.;Amadio, C.;Macorini, L.
    • Steel and Composite Structures
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    • v.2 no.2
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    • pp.85-98
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    • 2002
  • The aim of the paper is to present some results about the influence of rheological phenomena on steel-concrete composite beams. Both the cases of slab with normal and high performance concrete for one and two-span beams are analysed. A new finite element model that allows taking into account creep, shrinkage and cracking in tensile zones for concrete, along with non-linear behaviour of connection, steel beam and reinforcement, has been used. The main parameters that affect the response of the composite beam under the service load are highlighted. The influence of shrinkage on the slip over the supports is analysed, together with the cracking along the beam. At last, by performing a collapse analysis after a long-term analysis, the influence of rheological phenomena on the ductility demand of connection and reinforcement is analysed.