• Title/Summary/Keyword: 보 실험체

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Experimental Study on the Machenical Properties of Composite Beam Composed End Reinforced Concrete and Center Steel (RC-S 복합보의 역학적 특성에 관한 실험적 연구)

  • Kim, Cheol Hwan;Chae, Won Tak
    • Journal of Korean Society of Steel Construction
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    • v.14 no.5 s.60
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    • pp.675-682
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    • 2002
  • The beam of composite structure composed of the RC structure in the end part and steel structure in the central palt were investigated during cyclic loading, in order to evaluate strength, stiffness, and deformational capacity. The parameters used in this study include the amount of reinforced steel bar between the steel beam and RC structure and the existence of the sticking plate. Test results showed that all specimens had stabilized hysteresis loops. Likewise, the specimens with sticking plate had higher load-carrying capacity compared with the one without it. In addition, the stiffness of the composite structure was higher than the steel structure. All specimens also showed good rotational capacity.

Seismic Performance of Beam-Column Connections for Special Moment Frame Using 600 MPa Flexural Reinforcement (600 MPa 휨 철근을 사용한 특수 모멘트 골조의 보-기둥 접합부의 내진성능)

  • Hwang, Hyeon-Jong;Park, Hong-Gun;Choi, Won-Seok;Chung, Lan;Kim, Jin-Keun
    • Journal of the Korea Concrete Institute
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    • v.23 no.5
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    • pp.591-601
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    • 2011
  • An experimental study was performed to evaluate the seismic performance of beam-column connections using 600 MPa re-bars for beam flexural reinforcement. Three full scale specimens of interior beam-column connection and two specimens of exterior beam-column connection were tested under cyclic loading. The specimens were designed to satisfy the requirements of Special Moment Frame according to current design code. The structural performance of the specimens with 600 MPa re-bar were compared with that of the specimen with 400 MPa re-bars. The test results showed that bond-slip increased in the beam-column joint. However, the load-carrying capacity, deformation capacity, and energy dissipation capacity of the specimens with 600 MPa re-bar were comparable to those of the specimens with 400 MPa re-bars.

Experimental Study of Flexural Behavior of Steel Beam Strengthened with the Fiber Reinforced Polymer Plastic(FRP) Strips (섬유보강플라스틱(FRP) 스트립으로 보강한 철골보의 휨거동에 관한 실험적연구)

  • Choi, Sung Mo;Park, Jai Woo
    • Journal of Korean Society of Steel Construction
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    • v.26 no.2
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    • pp.69-79
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    • 2014
  • This paper presents the experimental results of flexural behavior of steel beam strengthened with fiber reinforced polymer plastic (FRP) strips subjected to static bending loading. Four H beams were fabricated strengthened with aramid strips and carbon strips and one control specimen were also fabricated. Among them two specimens were strengthened with partial length. The H-beams had two types of failure mode, depending on the length of the FRP strips:(1) strip debonding in beams with partial length reinforcement and (2) strip rupture in beams with full length reinforcement. From the test, it was observed that maximum increase of 16% was also achieved in bending-load capacity.

Crack Control of Flexure-Dominant Reinforced Concrete Beams Repaired with Strain-Hardening Cement Composite (SHCC) Materials (변형경화형 시멘트 복합체를 활용한 휨항복형 철근콘크리트 보의 균열제어)

  • Cha, Jun-Ho;Park, Wan-Shin;Lee, Young-Oh;Kim, Sun-Woo;Yun, Hyun-Do
    • Journal of the Korea Concrete Institute
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    • v.23 no.1
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    • pp.109-120
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    • 2011
  • This paper presents an experimental study results on the crack control of flexure-dominant reinforced concrete beams repaired with strain-hardening cement composite (SHCC). Five RC beams were fabricated and tested until failure. One unrepaired RC beam was a control specimen (CBN) and remaining four speciemens were repaired with SHCC materials. The test parameters included two types of SHCC matrix ductility and two types of repair method (patching and layering). Test results demonstrated that RC beams repaired with SHCC showed no concrete crushing or spalling until final failure, but numerous hair cracks were observed. The control specimen CBN failed due to crushing. It is important to note that SHCC matrix can improve crack-damage mitigation and flexural behavior of RC beams such as flexural strength, post peak ductility, and energy dissipation capacity. In the perspective of crack width, crack widths in RC beams repaired with SHCC had far smaller crack width than the control specimen CBN under the same deflection. Especially, the specimens repaired with SHCC of PVA0.75%+PE0.75% showed a high durability and ductility. The crack width indicates the residual capacity of the beam since SHCC matrix can delay residual capacity degradation of the RC beams.

Evaluation of Reinforcement Detail Effect on Coupling Beams (연결보의 배근 상세 효과 평가)

  • Lee, Hyun-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.25 no.2
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    • pp.49-57
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    • 2021
  • A study was conducted to secure structural performance as well as improve workability by improving the reinforcement details of special shear wall and coupling beams. Based on the specimen in which the existing diagonal bundle reinforcement and shear reinforcement were placed, the specimens replaced with thick diagonal reinforcing bars and the specimens replaced with horizontal reinforcing bars were selected as variables. As a result of the experiment, the specimen, which replaced the existing diagonal reinforcement with a thick-diameter reinforcement, showed a similar behavior to that of the basic specimen, and it was evaluated that it can be applied as an alternative to the details.

Evaluation of Shear Behavior of Precast RC Beams According to Replacement Ratio of Ground Granulated Blast Furnace Slag (고로슬래그 미분말 치환율에 따른 프리캐스트 철근콘크리트 보의 전단거동 평가)

  • Jeong, Chan-Yu;Kim, Young-Seek;Lee, Jin-Seop;Kim, Sang-Woo;Kim, Kil-Hee
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.18 no.2
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    • pp.82-89
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    • 2014
  • This study evaluates the shear performance of precast beams with ground granulated blast furnace slag. A total of four specimens according to replacement ratio of ground granulated blast furnace slag. The specimens under three loading points had a shear span-to-depth ratio of 2.5, and a rectangular section with a width of 200mm and a effect depth of 300 mm. In this study, existing equations were used for predicting the shear strength of the specimens. The shear strength by existing equations was compared with those of 89 reinforced concrete beams without shear reinforcement. It can be shown from experimental results that all specimens with ground granulated blast furnace slag showed a similar shear strength as compared with the specimen with portland cements alone.

An Experimental Study on the Shear Behavior of Reinforced Concrete Beams Strengthened with Slit Type Steel Plates (Slit형(形) 강판으로 보강(補强)한 철근콘크리트 보의 전단거동에 관한 실험연구)

  • Lee, Choon-Ho;Shim, Jong-Seok;Kwon, Ki-Hyuk
    • Journal of the Korean Society of Hazard Mitigation
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    • v.8 no.4
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    • pp.1-8
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    • 2008
  • RC beam of existing structures often encounter shear problems for various reasons. The shear failure of RC beam is sudden and brittle. Strengthening technique jacketing with external bonding of steel plates(or CFRP and CFS) with epoxy is many use to in practice. This study presents test results on strengthening shear deficient RC beams by external bonding of slit type steel plates. Test parameters are width, interval, length, thickness and angle of slit in steel plates. The purpose was to evaluate the reinforcing effects, failure modes and shear capacities for RC beams of strengthened with various slit type steel plates. The test result confirmed that all slit steel plates improved the stiffness and strength of the specimens significantly. Failure modes of SV series and SD series showed shear fractures and flexure fractures at ultimate state respectively. SD series were ductile rather than SV series.

Strength and Ductility of Steel Fiber Reinforced Composite Beams without Shear Reinforcements (전단보강근이 없는 강섬유 보강 합성보의 강도 및 연성 능력)

  • Oh, Young-Hun;Nam, Young-Gil;Kim, Jeong-Hae
    • Journal of the Korea Concrete Institute
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    • v.19 no.1
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    • pp.103-111
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    • 2007
  • Experimental study was carried out to investigate the structural performance of composite beams with steel fiber concrete and angle. For this purpose, seven specimens composed of two RC beams with or without steel fiber and five composite beams with steel fiber and angle were constructed and tested. All specimens had no web shear reinforcement. Main variables for the specimens were tensile reinforcement ratio and fiber volume fraction. Based on the test results, structural performance such as strength, stiffness, ductility and energy dissipation capacity was evaluated and compared with the predicted strength. The prediction of flexure and shear strength gives a good relationship with the observed strength. The strength, ductility and energy dissipation capacity are increased, as the fiber volume fraction is increased. Meanwhile, high tensile reinforcement ratio resulted in the reduction of ductility and energy dissipation capacity for the composite beams.

Strength Evaluation for Doubly Reinforced Composite Beams with Steel Fiber Concretes and Steel Angles (강섬유 콘크리트와 형강을 사용한 합성 복근보의 강도 특성)

  • Oh, Young-Hun;Nam, Young-Gil;Lee, Jae-Yeon
    • Journal of the Korea Concrete Institute
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    • v.20 no.6
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    • pp.755-763
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    • 2008
  • The purpose of this study is to investigate the structural performance of doubly reinforced composite beams with steel fiber concretes and steel angles. For this purpose, total 6 specimens whose variables are shear span-to-depth ratio, existence of shear reinforcement, and shear reinforcement details, are made and tested. All specimens are constructed of steel fiber concretes with specified compressive strength of 30 MPa and steel fiber volumn content of 1%. From the experimental results, structural performance of doubly reinforced composite beams are evaluated in terms of strength, stiffness, ductility, and energy absorbing capacity. For the better structural performance, it is recommended that the composite beam is designed with diagonal shear reinforcement.

Structural Performance of Beam-Column Connections Using 51 mm Diameter with Different Anchorage Details (51 mm 대구경 철근을 사용한 외부 보-기둥 접합부의 정착상세별 구조성능 평가)

  • Kim, Jung-Yeob;Jung, Hyung-Suk;Chun, Sung-Chul;Kim, In-Ho;Choi, Chang-Sik
    • Journal of the Korea Concrete Institute
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    • v.29 no.2
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    • pp.201-208
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    • 2017
  • In exterior beam-column joints, hooked bars are used for anchorage, but usage of high-strength and large-diameter bars increases, headed bar is preferred for solving steel congestion and difficulty in construction. To investigate the structural performance of headed bars, Six exterior beam-column joints were tested under cyclic loading. Tests parameter were the anchorage methods and concrete strength. The test results indicate that behavior of headed bar specimens shows similar performance with hooked bar specimens. All specimens failed by flexural failure of the beam. Headed bar specimens shows better performance in anchorage and joint shear. All specimens were satisfied the criteria of ACI374.1-05. Test results indicate that use of headed bar in exterior beam column joint is available.