• Title, Summary, Keyword: RC교각

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Behaviors of Internally Confined Hollow Reinforced Concrete Piers by Thickness of Internal Steel Tube (내부 강관 두께에 따른 내부 구속 중공 RC 교각의 거동)

  • Choi, Jun-Ho;Han, Taek-Hee;Yi, Gyu-Sei;Yoon, Ki-Yong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.8 no.2
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    • pp.333-338
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    • 2007
  • An infernally confined hollow reinforced concrete pier (ICH RC pier) is hollow RC pier which has a internal steel tube to enhance its ductility and stiffness by internal confinement. In this study, the internal steel tube were changed to investigate the behavior of ICH RC pier. The behavior of internally confined hollow reinforced concrete piers were evaluated with safety ratio, ductility, total material cost, the total weight of the pier, etc. As a result of analytical study, the usage of a minimum necessary thickness of the internal steel tube the most effective. The ICH RC pier has decrease of weight compare to Solid RC pier.

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A study on behavior for prefabricated precast segment and similar piers (조립식 프리캐스트 세그먼트 교각과 유사형식 교각에 대한 거동에 관한 연구)

  • Jeong, Hyeok-Chang;Kim, Ick-Hyun;Kim, Tae-Hun;Kim, Young-Jin
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.33-36
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    • 2008
  • The present, most of bridges have been constructed with RC piers in Korea. But the construction of bridges with RC piers is limited to certain working environment and weather that give rise to some series trouble such as weak constructability, quality deterioration and rising of the cost of construction. For this reason, the construction tend to focus on the developing of more effective and economical construction methods. Of all methods, prefabricated precast segment piers have been examined more extensively, it has become a solution of some problems like traffic congestion that usual site placing methods have. The Korea government has the already issued specification earthquake effect. But the existing seismic specification are inapplicable to bridges with prefabricated precast segment piers. This study analyzes structural behabviors of the RC model, prestressted pier moel, the prefabricated precast segment pier with no shearduct model and the prefabricated segment piers with shearduct and changed post tensioning force.

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A Parameter Study of Internally Confined Hollow Reinforced Concrete Piers (내부 구속 중공 RC 교각의 매개변수 연구)

  • Choi, Jun-Ho;Yoon, Ki-Yong;Han, Taek-Hee;Kang, Young-Jong
    • Journal of the Korean Society of Hazard Mitigation
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    • v.10 no.4
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    • pp.17-24
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    • 2010
  • The hollow RC(Reinforced concrete) pier has the merit of lightweight pier compared with solid RC pier. However, the hollow RC pier shows a low ductile behavior due to brittle failure of inside concrete. To overcome this problem, the internally confined hollow reinforced concrete column has been developed. In this study, the behavior of internally confined hollow RC piers were evaluated with safety ratio, ductility, total material cost, the total weight of the pier, etc. The chosen parameters for the study are hollow ratio, thickness of internal steel tube, intervals between vertical re-bars, numbers of horizontal re-bars, and strength of concrete. As a result of parameters study, the usage of a minimum necessary thickness of the internal steel tube is the most effective.

Optimization of Reinforced Concrete Piers Based on Efficient Reanalysis Technique (효율적인 재해석 기법에 의한 철근콘크리트 교각의 최적설계)

  • 조효남;민대홍;신만규
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.14 no.4
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    • pp.505-513
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    • 2001
  • In this study, an optimum design algorithm using efficient reanalysis is proposed for seismic design of Reinforced Concrete (RC) piers. The proposed algorithm for optimization of RC piers is based on efficient reanalysis technique. Considering structural behavior of RC piers, the other approximation technique such as artificial constraint deletion is introduced to increase the efficiency of optimization. The efficiency and robustness of the proposed algorithm including the proposed reanalysis technique is demonstrated by comparing it with a conventional optimization algorithm. A few of design examples are optimized to show the applicability of the proposed algorithm.

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Limited-Ductile Seismic Design and Performance Assessment Method of RC Bridge Piers Based on Displacement Ductility (변위연성도 기반 철근콘크리트 교각의 한정연성 내진 설계법과 성능평가 방법)

  • Park, Chang-Kyu;Chung, Young-Soo;Lee, Dae-Hyoung
    • Journal of the Korea Concrete Institute
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    • v.19 no.1
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    • pp.19-26
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    • 2007
  • Until recently Korea is considered to be immune from the earthquake hazard because it is located for away from the active fault. However, we have noticed that recent strong earthquakes inflicted enormous losses on human lives and nation's economy all over the world. Hence, there has been raised the importance of the earthquake resistant design for various infrastructures. In this research, new methodologies for the seismic design and performance assessment of reinforced concrete(RC) bridge pier were proposed from experimental results of 82 circular RC bridge piers and 54 rectangular RC bridge piers tested in domestic and aboard. New seismic design method was based on the concept of the limited ductile design, which could be practically used for low or moderate seismic regions like Korea. Further study for the seismic safety of RC bridge piers was carried out to enhance the seismic performance of aged RC bridge piers, which were designed and constructed before implementing the 1992 seismic design provision in Korea. New formula for the seismic performance assessment of RC bridge piers was proposed and practically used for the decision on the need of repair and retrofit of many aged RC bridge piers.

Pseudo Dynamic Test for the Seismic Performance Evaluation of Circular RC Bridge Piers Retrofitted with Fibers (섬유보강 원형 RC교각의 내진성능 평가를 위한 유사동적실험)

  • 정영수;박종협;박희상
    • Journal of the Earthquake Engineering Society of Korea
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    • v.5 no.2
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    • pp.49-57
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    • 2001
  • 본 연구의 목적은 유사동적실험에 의한 섬유보강 원형 RC교각의 내진성능평가를 위한 연구로서 수원시에 위치한 내진교량인 하길교를 대상모델로 하였으며, 도로교 표준시방서의 내진설계규정이 적용되지 않은 비내진교각시험체 2본 및 내진성능향상을 위한 섬유보강시험 4본, 즉 총 6본에 대하여 유사동적실험을 수행하였다. 보강공법으로는 유리 탄소섬유 보강공법을 사용하였으며, 실험변수로는 입력지진동, 섬유고방유무로 하였다. 그리고 내진성능평가 방법은 입력 및 소산에너지, 변위 연성도가 분석되었다. 본 실험의 결과 유리 섬유로 보강된 비내진시험체의 변위연성도 KHC인공지진파에 대하여 7.7~9.0정도의 값으로 충분한 내진성능을 확보하고 있는 것으로 평가되었다.

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Seismic Performance Analysis of RC Bridge Piers with 3.5 Aspect Ratio depending on Testing Methods (형상비 3.5 RC교각의 실험 방법에 의한 내진성능 분석)

  • Hong, Hyun-Ki;Park, Chang-Young;Chung, Young-Soo
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.93-96
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    • 2008
  • This paper deals with the shaking table test(STT), the Quasi-Static Test(QST), and the Pseudo-Dynamic Test(PDT) to evaluate the seismic performance of RC bridge piers under near fault ground motion. Five scaled specimens were constructed the weight of the superstructure was applied through the prestressing strand at the centroid of the column section during the QST and PDT. However, the STT was simulated. The lateral inertia force of the superstructure by the mass frame which was linked with the pier because of the limited payload of shaking table. Particularly for the STT, friction underneath the mass frame was minimized by special details and it was verified by a series of pre-load test. Scale factor of the RC piers was 4.25.

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Seismic Curvature Ductility of RC Bridge Piers with 2.5 Aspect Ratio (형상비 2.5의 RC 교각의 내진 곡률연성도)

  • Chung, Young-Soo;Park, Chang-Kyu;Lee, Eun-Hee
    • Journal of the Earthquake Engineering Society of Korea
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    • v.8 no.3
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    • pp.1-12
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    • 2004
  • Due to the 1989 Loma Prieta, 1995 Hyogoken Nambu earthquakes, etc, a number of bridge columns  were collapsed in flexure-shear failures as a consequence of the premature termination of the column longitudinal reinforcement. Nevertheless, previous researches for the performance of bridge columns were concentrated on the flexural failure mode. It is well understood that the seismic behaviour of RC bridge piers was dependent on the performance of the plastic hinge of RC bridge piers, the ductility of which was desirable to be computed on the basis of the curvature. Experimental investigation was made to evaluate the variation of the curvature of the plastic hinge  region for the seismic performance of earthquake-damaged RC columns in flexure-shear failure mode. Seven test specimens in the aspect ratio of 2.5 were made with test parameters: confinement ratios, lap splices, and retrofitting FRP materials. They were damaged under series of artificial earthquakes that could be compatible in Korean peninsula. Directly after the pseudo-dynamic test, damaged columns were retested under inelastic reversal cyclic loading under a constant axial load, $P=0.1f_{ck}A_g$. Residual seismic capacity of damaged specimens was evaluated by analzying the moment-curvature hysteresis and the curvature ductility. Test results show that the biggest curvature was developed around 15cm above the footing, which induced the column failure. It was observed that RC bridge specimens with lap-spliced longitudinal steels appeared to fail at low curvature ductility but significant improvement was made in the curvature ductility of RC specimens with FRP straps wrapped around the plastic hinge region. Based on the experimental variation of the curvature of RC specimens, new equivalent length of the plastic hinge region was proposed by considering the lateral confinement in this study. The analytical and experimental relationship between the displacement and the curvature ductility were compared based on this proposal, which gave excellent result.

Evaluation of Seismic Damage for RC Bridge Piers II : Numerical Analysis (철근콘크리트 교각의 지진손상 평가 II : 수치해석 예)

  • 김태훈;김운학;신현목
    • Journal of the Earthquake Engineering Society of Korea
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    • v.6 no.3
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    • pp.41-52
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    • 2002
  • In the companion paper, nonlinear finite element analysis procedures are presented for the seismic damage evaluation of RC bridge piers. This paper defines a damage index based on the predicted hysteretic behavior of a RC bridge pier. Damage indices aim to provide a means of quantifying numerically the damage in RC bridge piers sustained under earthquake loading. The proposed numerical method is applied to RC bridge piers tested by other, and compared to existing damage indices. The proposed numerical method gives a realistic prediction of damage throughout the loading cycles for several test specimens investigated.

Displacement Ductility Ratio of Reinforced Concrete Bridge Piers with Lap-splices (주철근 겹침이음 비율에 따른 RC교각의 연성능력 평가)

  • Park, Kwang-Soon;Ju, Hyeong-Seok;Shin, Hyun-Mock;Kim, Moon-Kyum
    • Journal of the Earthquake Engineering Society of Korea
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    • v.12 no.6
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    • pp.1-12
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    • 2008
  • As internal and external seismic experiment results, the seismic performance of RC bridge piers is largely dependent on the ratio of lap-spliced bars to all longitudinal reinforcing bars in plastic hinge regions, and confining effects of transverse reinforcements. Capacity and displacement ductility of non-seismically designed existing RC piers are reduced by lap splices in plastic hinge regions. The provision for the lap splice of longitudinal reinforcing bars was not specified in KBDS (Korean Bridge Design Specifications) before the implementation of 1992 seismic design code, but the ratio of lap-spliced bars to all longitudinal reinforcing bars in plastic hinge regions is restricted to 50% in the 2005 version of KBDS. This paper presents a seismic assessment of RC piers at lap-splicing ratios of 0%, 50%, and 100%. Through a comparison of experimental and analytic results of RC piers, we introduce an appropriate ultimate strain of confined concrete in plastic hinge regions with lap-splices, and propose a method for estimating displacement ductility ratios of non-seismically designed existing RC piers using fiber element analysis.