• Title, Summary, Keyword: 중공원형 철근콘크리트 교각

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Seismic Performance Assessment of Hollow Circular Reinforced Concrete Bridge Columns with Confinement Steel (중공원형 철근콘크리트 교각의 횡방향철근에 따른 내진성능평가)

  • Kim, Tae-Hoon;Kang, Hyeong-Taek
    • Journal of the Earthquake Engineering Society of Korea
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    • v.16 no.1
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    • pp.13-25
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    • 2012
  • The purpose of this study was to investigate the seismic behavior of hollow circular reinforced concrete bridge columns with confinement steel, and to develop improved seismic design criteria. Three hollow circular columns were tested under a constant axial load and a quasi-static, cyclically reversed horizontal load. The accuracy and objectivity of the assessment process can be enhanced by using a sophisticated nonlinear finite element analysis program. The numerical method used gives a realistic prediction of the seismic performance throughout the loading cycles for the several test specimens investigated. Based on the experimental and analytical results, design recommendations are presented to improve current practice in the design and construction of hollow circular reinforced concrete bridge columns.

Nonlinear Finite Element Analysis of Circular Hollow Reinforced Concrete Columns Based on Design Variables (설계변수에 따른 중공원형 철근콘크리트 교각의 비선형 유한요소해석)

  • Cheon, Ju-Hyun;Lee, Seung-Jin;Lee, Byung-Ju;Lee, Jae-Hoon;Shin, Hyun-Mock
    • Journal of the Earthquake Engineering Society of Korea
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    • v.15 no.2
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    • pp.35-42
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    • 2011
  • The seismic design of solid reinforced concrete bridge columns has been committed to, based on accumulated research and design specifications. The rational confinement model and seismic performance evaluation, however, are insufficient because of the lack of domestic and foreign design specifications about the experimental and analytical difficulties in the case of circular hollow reinforced concrete columns. In this paper, the seismic behavior of circular hollow reinforced concrete columns and its dependence on design variables are understood and explained. These research results can be used to derive the rational and economical design specifications for circular hollow sectional columns based on the result from the nonlinear analysis program, named RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology).

Failure Behavior of Hollow Circular RC Column According to the Spacing of Spirals (나선철근 간격에 따른 중공 원형 RC 기둥의 파괴거동)

  • Ko, Seong-Hyun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.20 no.6
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    • pp.46-55
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    • 2016
  • Three small scale hollow circular reinforced concrete columns(4.5 aspect ratio) were tested under cyclic lateral load with constant axial load. Diameter of section is 400 mm, hollow diameter is 200 mm. The selected test variable are transverse steel ratio. Volumetric ratio of spirals of all the columns is 0.302~0.604% in the plastic hinge region. It corresponds to 45.9~91.8% of the minimum requirement of confining steel by Korean Bridge Design Specifications, which represent existing columns not designed by the current seismic design specifications or designed by seismic concept. The final objectives of this study are to provide quantitative reference data and tendency for performance or damage assessment based on the performance levels such as cracking, yielding, steel fracture, etc. In this paper, describes mainly failure behavior, strength degradation behaviour, displacement ductility of circular reinforced concrete bridge columns with respect to test variables.

Quasi-Static Test for Seismic Performance of Circular Hollow RC Bridge Pier (원형 중공 콘크리트 교각의 내진성능에 대한 준정적 실험)

  • 정영수;한기훈;이강균;이대형
    • Journal of the Earthquake Engineering Society of Korea
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    • v.3 no.2
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    • pp.41-54
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    • 1999
  • Because of relatively heavy dead weight of concrete itself and unavoidable heat of massive concrete in bridge piers, circular hollow columns are widely used in Korean highway bridges. Since the occurrence of 1995 Kobe earthquake, there have been much concerns about seismic design for various infrastructures, inclusive of bridge structures. It is, however, understood that there are not much research works for nonlinear behavior of circular hollow columns subjected to eqrthquake motions. The objective of this experimental research is to investigate nonlinear behavior of circular hollow reinforced concrete bridge piers under the quasi-static cyclic load, and then to enhance their ductility by strengthening the plastic hinge region with glassfiber sheets. Particularly for this test, constant 10 cyclic loads have been repeatedly actuated to investigate the magnitude of strength degradation for the displacement ductility factor. Important test parameters are seismic design, confinement steel ratio, axial force and load pattern. It is observed from quasi-static tests for 7 bridge piers that the seismically designed columns and the retrofitted columns show better performance than the nonseismically designed colums, i.e. about 20% higher for energy dissipation capacity and about 70% higher for curvatures.

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Seismic Performance and Flexural Over-strength of Hollow Circular RC Column with Longitudinal Steel Ratio 2.017% (축방향철근비 2.017%인 중공 원형 RC 기둥의 내진성능과 휨 초과강도)

  • Ko, Seong-Hyun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.21 no.1
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    • pp.1-8
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    • 2017
  • Three small scale hollow circular reinforced concrete columns with aspect ratio 4.5 were tested under cyclic lateral load with constant axial load. Diameter of section is 400 mm, hollow diameter is 200 mm. The selected test variable is transverse steel ratio. Volumetric ratios of spirals of all the columns are 0.302~0.604% in the plastic hinge region. It corresponds to 45.9~91.8% of the minimum requirement of confining steel by Korean Bridge Design Specifications, which represent existing columns not designed by the current seismic design specifications or designed by seismic concept. The longitudinal steel ratio is 2.017%. The axial load ratio is 7%. This paper describes mainly crack behavior, load-displacement hysteresis loop, seismic performance such as equivalent damping ratio, residual displacement and effective stiffness and flexural over-strength of circular reinforced concrete bridge columns with respect to test variable. The regulation of flexural over-strength is adopted by Korea Bridge Design Specifications (Limited state design, 2012). The test results are compared with nominal strength, result of nonlinear moment-curvature analysis and the design specifications such as AASHTO LRFD and Korea Bridge Design Specifications(Limited state design).

Ductility Evaluation of Circular Hollow Reinforced Concrete Columns with Internal Steel Tube (강관 보강 중공 R.C 기둥의 연성 평가 해석)

  • Han, Seung Ryong;Lim, Nam Hyoung;Kang, Young Jong;Lee, Gyu Sei
    • Journal of Korean Society of Steel Construction
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    • v.15 no.1
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    • pp.1-8
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    • 2003
  • In locations where the cost of concrete is relatively high or in situations where the weight of concrete members has to be kept to a minimum, it may be more economical to use hollow reinforced concrete vertic al members. Hollow reinforced concrete colun-ms with a low axial load, a moderate longitudinal steel percentage and a reasonably thick wall were found to perform in a ductile manner at the flexural strength, similar to solid columns. Hollow reinforced concrete columns with a high axial load, a high longitudinal steel percentage, and a thin wall were found, however, to behave in a brittle manner at the flexural strength, since the neutral axis is forced to occur away from the inside face of the tube towards the section centroid and, as a result, crushing of concrete occurs near the unconfined inside face of the section. If, however, a steel tube is placed near the inside face of a circular hollow column, the column can be expected not to fail in a brittle manner through the disintegration of the concrete in the compression zone. A design recommendation and example through the moment-curvature analysis program for curvature ductility are herein presented. A theoretical moment-curvature analysis for reinforced concrete columns, indicating the available flexural strength and ductility, can be conducted, providing that the stress-strain relation for the concrete and steel are known. In this paper, a unified stress-stain model for confined concrete by Mander is developed foi members with circular sections.

Characteristics of the Stress-strain Relationship of Square Sectional Concrete Confined by Hoop Reinforcement with Cross-ties (후프띠철근과 보강띠철근으로 횡구속된 정사각단면 콘크리트의 응력-변형률 특성)

  • Jeong, Hyeok-Chang;Cha, Soo-Won;Kim, Ick-Hyun
    • Journal of the Earthquake Engineering Society of Korea
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    • v.14 no.3
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    • pp.39-48
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    • 2010
  • Improved seismic performances of RC bridges can be attained by sufficient ductilities of piers, which can be obtained by providing sufficient lateral confinements to the plastic hinge regions of piers. The cross sectional shape and the amount of lateral reinforcements are key parameters in the determination of effective confinements. Even though identical amounts of lateral reinforcement are provided, the effective confinement differs due to different spacing, arrangements, hook details and so on. Unlike circular sections in which confinement is exerted by mere hoop reinforcements, cross-ties are arranged in square or rectangular sections to enhance the effective confinements. The stress-strain relationship of confined concrete is varied by how to consider these cross-ties. In this study, the stress-strain relationships of confined concrete with cross-ties are investigated experimentally and their mechanical characteristics are estimated by comparison with other empirical equations.

Transverse Reinforcement for Circular Internally Confined Hollow RC column (원형 내부 구속 중공 RC 기둥의 심부 구속 횡방향 철근 연구)

  • Won, Deok Hee;Han, Taek Hee;Park, Woo Sun;Park, Jong Sub;Kang, Young Jong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.2
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    • pp.927-935
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    • 2013
  • Recently, bridge structures has progressed the researches about seismic performance by occurrence of earthquake increased compared with the past. In the substructure of bridge, confining transverse reinforcement has arranged in plastic hinge region to resist the lateral load which increased the lateral confining effect. Columns are increased the seismic performance through secure of the stiffness and ductility The design specification for arrangement of confining transverse reinforcement same specification of domestic and international that suggested to solid reinforced concrete column(RC). This design specification have limits for Internally Confined Hollow RC(ICH RC) column because of different the component and performance characteristics of column. In this paper suggested the modified equation for economics and rational design through investigation of displacement ductility when applied the existing specification at the steel composite hollow RC column.