• Title/Summary/Keyword: ECC 기둥

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Cyclic Responses of Steel Reinforced ECC Column under Reversed Cyclic Loading Conditions (철근 보강된 ECC 기둥의 반복하중에 대한 이력거동)

  • Hyun, Jung-Hwan;Shim, Young-Heung;Bang, Jin-Wook;Kim, Yun-Yong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.4
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    • pp.75-82
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    • 2015
  • In this study, experimental research was carried out to evaluate steel reinforced ECC (Engineered Cementitious Composites) column, which exhibits excellent crack control property and highly ductile behavior. Ordinary portland cement and high volume fly ash were used as binding materials in the mixture proportions for the purpose of achieving a high level of multiple cracking property with the tightly controlled crack width. To compare with the cyclic behavior of steel reinforced ECC column specimen, a conventional reinforced concrete column was prepared and tested under reversed cyclic loading condition. Based on the cyclic load test, ECC column exhibited higher cyclic behavior, compared to the conventional RC column, in terms of load carrying capacity and energy dissipation capacity.

Fire Resistance Properties of High Strength Concrete Column using ECC Permanent Form (ECC 영구 거푸집을 활용한 고강도콘크리트 기둥부재의 내화특성)

  • Kim, Yong-Ro;Song, Young-Chan;Kim, Ook-Jong;Lee, Do-Bum
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.957-960
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    • 2008
  • In this study, it was investigated fire resistance properties of high strength concrete column using Engineered Cementitious Composites(ECC) permanent form as a countermeasure for explosive spalling of concrete on fire. As a test result, it was appeared that ECC permanent form is available as fire resistance method of high strength concrete if it is developed manufacturing technique and scheme for application controlling heat penetration through interface of permanent form and high strength concrete, and setting up mix proportion and thickness of ECC.

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Structural Capacity Evaluation of Hybrid Precast Concrete Beam-Column Connections Subjected to Cyclic Loading (반복하중을 받는 하이브리드 프리캐스트 보-기둥 접합부의 성능평가)

  • Choi, Hyun-Ki;Yoo, Chang-Hee;Choi, Yun-Cheul;Choi, Chang-Sik
    • Journal of the Korea Concrete Institute
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    • v.22 no.3
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    • pp.325-333
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    • 2010
  • In this study, new moment-resisting precast concrete beam-column joint made up of hybrid steel concrete was developed and tested. This beam-column joint is proposed for use in moderate seismic regions. It has square hollow tubular section in concrete column and connecting plate in precast U-beam. The steel elements in column and beam members were connected using bolt. Furthermore, in order to prevent the premature failure of concrete in hybrid steel-concrete connection, ECC(engineered cementitious composite) was used. An experimental study was carried out investigating the joint behavior subjected to reversed cyclic loading and constant axial compressive load. Two precast beam-column joint specimens and monolithic reinforced concrete joint specimen were tested. The variables for interior joints were cast-in-situ concrete area and transverse reinforcement within the joint. Tests were carried out under displacement controlled reverse cyclic load with a constant axial load. Joint performance is evaluated on the basis of connection strength, stiffness, energy dissipation, and displacement capacity. The test results showed that significant differences in structural behavior between the two types of connection because of different bonding characteristics between steel and concrete; steel and ECC. The proposed joint detail can induce to move the plastic hinge out of the ECC and steel plate. And proposed precast connection showed better performance than the monolithic connection by providing sufficient moment-resisting behavior suitable for applications in moderate seismic regions.

A Study on the Structural Performance of Slab-column Joint at Flat Plate Structure Using ECC (고인성 시멘트 복합재를 활용한 플랫플레이트 구조의 슬래브-기둥 접합부 구조성능 연구)

  • Choi, Kwang-Ho;Park, Byung-Chun;Choi, Sung-Woo;Ryu, Deug-Hyun
    • Journal of the Korea Concrete Institute
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    • v.29 no.2
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    • pp.209-216
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    • 2017
  • One of the important considerations in structural designing the flat plate system is ensuring the resistance to punching shear caused by axial loads and the ductile ability to follow horizontal deformation under earthquake. In this study, the ECC (Engineered Cementitious Composite) has been placed in the critical section zone of punching shear at slab-column joint to improve ductility and the advanced details of shear reinforced area nearby critical section zone has been developed using stud and steel fiber. The shear performance tests were performed on the specimens with parameters of fiber type mixed with ECC, stud and steel fiber set into the shear reinforced area in which the failure pattern, joint strength, displacement and strain of the specimen were compared and analyzed. The test results showed that the strength and ductility of specimens with ECC applied to joint were better than those of RC flat plate system. Also, the shear reinforcement effect of stud and the ductility improvement of steel fiber concrete were confirmed in the shear reinforcement area.

Hysteretic Behavior and Seismic Resistant Capacity of Precast Concrete Beam-to-Column Connections (프리캐스트 콘크리트 보-기둥 접합부의 이력거동 및 내진성능)

  • Choi, Hyun-Ki;Choi, Yun-Cheul;Choi, Chang-Sik
    • Journal of the Earthquake Engineering Society of Korea
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    • v.14 no.4
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    • pp.61-71
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    • 2010
  • Five half-scale beam-to-column connections in a precast concrete frame were tested with cyclic loading that simulated earthquake-type motions. Five half -scale interior beam-column assemblies representing a portion of a frame subjected to simulated seismic loading were tested, including one monolithic specimen and four precast specimens. Variables included the detailing used at the joint to achieve a structural continuity of the beam reinforcement, and the type of special reinforcement in the connection (whether ECC or transverse reinforcement). The specimen design followed the strong-column-weak-beam concept. The beam reinforcement was purposely designed and detailed to develop plastic hinges at the beam and to impose large inelastic shear force demands into the joint. The joint performance was evaluated on the basis of connection strength, stiffness, energy dissipation, and drift capacity. From the test results, the plastic hinges at the beam controlled the specimen failure. In general, the performance of the beam-to-column connections was satisfactory. The joint strength was 1.15 times of that expected for monolithic reinforced concrete construction. The specimen behavior was ductile due to tensile deformability by ECC and the yielding steel plate, while the strength was nearly constant up to a drift of 3.5 percent.

A Development and Characterization of Refractory Panel (내화패널의 개발과 특성에 관한 연구)

  • Kim, Dong-Joon;Kwon, Young-Jin;Kim, Yong-Ro;Han, Byung-Chan;Kim, Jae-Hwan
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • 2009.04a
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    • pp.61-66
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    • 2009
  • 최근 초고층 건축물 등에 적용되는 고강도콘크리트의 내화성능에 대한 문제점이 제기됨에 따라 국토해양부에서는 고강도콘크리트 내화성능 관리 기준을 고시한 바 있으며, 건설업계에서도 이에 대응하기 위해 다양한 기술 검토가 이루어지고 있다. 본 연구에서는 고강도콘크리트의 취약점으로 제기되고 있는 화재시의 폭렬문제에 대한 대응방안으로서 기존 연구를 통해 내화성능이 우수한 것으로 보고되고 있는 ECC 를 영구거푸집으로 활용한 고강도콘크리트의 내화성능을 검토하였다. ECC 영구거푸집을 활용한 고강도콘크리트 기둥부재의 내화성능 검토 결과, 영구거푸집과 고강도콘크리트 계면으로의 열 침투를 제어할 수 있도록 부재 생산 및 구축 방안을 검토하고, ECC의 적정 배합 및 두께를 확보한다면 고강도콘크리트의 내화성능 확보기술로서의 활용이 가능할 것으로 판단된다. 또한, 내화성 영구거푸집으로서의 단순 활용 방안 이외에 ECC의 우수한 물리적 성능을 활용하여 구조성능을 분담할 수 있는 방안으로의 지속적 검토가 필요할 것으로 판단된다.

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The Seismic Performance of Non-Ductile Reinforced Concrete (RC) Frames with Engineered Cementitious Composite (ECC) Wing Panel Elements (ECC 날개벽 요소로 보강된 비내진상세를 갖는 철근콘크리트 골조의 내진성능)

  • Kang, Dae-Hyun;Ok, Il-Seok;Yun, Hyun-Do;Kim, Jae-Hwan;Yang, Il-Seung
    • Journal of the Korea Concrete Institute
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    • v.27 no.5
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    • pp.541-549
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    • 2015
  • This study was conducted to experimentally investigate the seismic retrofitting performance of non-ductile reinforced concrete (RC) frames by introducing engineered cementitious composite (ECC) wing panel elements. Non-ductile RC frame tested in this study were designed and detailed for gravity loads with insufficient or no consideration to lateral loads. Therefore, Non-ductile RC frame were not satisfied on present seismic code requirements. The precast ECC wing panels were used to improve the seismic structural performance of existing non-ductile RC frame. A series of experiments were carried out to evaluate the structural performance of ECC wing panel elements alone a non-ductile RC frame strengthened by adding ECC panel elements. Failure pattern, strength, stiffness and energy dissipation characteristics of specimens were evaluated based on the test results. The test results show that both lateral strength and stiffness were significantly improved in specimen strengthened than non-ductile RC frame. It is noted that ECC wing wall elements application on non-ductile RC frame can be effective alternative on seismic retrofit of non-ductile building.

Analytical Study on Hybrid Precast Concrete Beam-Column Connections (하이브리드 프리캐스트 보-기둥 접합부의 해석적 연구)

  • Choi, Chang-Sik;Kim, Seung-Hyun;Choi, Yun-Cheul;Choi, Hyun-Ki
    • Journal of the Korea Concrete Institute
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    • v.25 no.6
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    • pp.631-639
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    • 2013
  • Non-linear finite element analysis for newly developed precast concrete details for beam-to-column connection which can be used in moderate seismic region was carried out in this study. Developed precast system is based on composite structure and which have steel tube in column and steel plate in beam. Improving cracking strength of joint under reversed cyclic loading, joint area was casted with ECC (Engineering Cementitious Composites). Since this newly developed precast system have complex sectional properties and newly developed material, new analysis method should be developed. Using embedded elements and models of non-linear finite element analysis program ABAQUS previously tested specimens were successfully analyzed. Analysis results show comparatively accurate and conservative prediction. Using finite element model, effect of axial load magnitude and flexural strength ratio were investigated. Developed connection have optimized performance under axial load of 10~20% of compressive strength of column. Plastic hinge was successfully developed with flexural strength ratio greater than 1.2.

An Experimental Study on the Mechanical Properties of Ductile Outline Form and Fire Resistance of High Strength RC Column (고인성 외곽 거푸집의 역학성능 및 이를 활용한 고강도 RC기둥의 내화성능에 관한 실험적 연구)

  • Rho, Hyoung-Nam;Kim, Jae-Hwan;Kim, Yong-Ro;Kim, Wook-Jong;Kwon, Young-Jin;Lee, Sang-Soo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2008.11a
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    • pp.199-203
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    • 2008
  • With recent trend in domestic and global market requiring architectures' conversion into skyscrapers seasoned with the features of landmarks, structural problems in relation with explosive spatting during fire emergencies are arising as controversial issues. Accordingly, many productive researches have been made in relation to the reinforcement techniques for improving fire resistance and the number of applications in the field is gradually increasing. In this study, a ductile outline form using ECC (Engineered Cementations Composites) was made with improvements on the structure and fire resistance to examine its applicability. Also, currently in Japan, the number of studies and applications is increasing focusing on reduction of construction time and improvement of workability with application of Half-PCa method. However, using such method of construction, large structural members decrease the utilization of space and architecture-wise, there is a disadvantage of the weight increase. Therefore, in such context, it would be worth reducing the weight of the structural members by reducing the size using ECC. In addition, its excellent pseudo strain-hardening due to fiber may have great effects on seismic designs. In the mean time, this study planned 3 equal conditions for mix water, PVA fiber and additives excluding binder and refractory to evaluate the mechanical properties of resistance against pressure and internal force. Finally, an evaluation was executed on the fire resistance of the newly made ductile outline form. As a result, from ECC-I to ECC-III, all showed excellent mechanical properties due to pseudo strain-hardening and in the fire resistance test conducted with ISO 834 heating curve, most of them tended to be in the range of the reference temperature (538℃-180min), so there was no occurrence of any explosive spatting.

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Evaluation of Fire Performance for High Strength Concrete Mock-up Column with Fiber by Unloaded Fire Test (비재하 내화시험에 의한 섬유혼입 고강도 콘크리트 Mock-up 기둥의 내화성능 평가)

  • Song, Young-Chan;Kim, Yong-Ro;Kim, Ook-Jong;Lee, Do-Bum
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2009.11a
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    • pp.97-100
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    • 2009
  • Fire resistance properties and mechanical properties of high strength concrete mock-up column using organic fiber by KS F 2257 Methods of fire resistance test for elements of building construction and compression test was investigated for application of precast concrete column method of high rise building in this study. As a test result, it was appeared that ECC permanent form is available as fire resistance method of high strength concrete and new precast concrete construction method for facilitating construction of high rise building.

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