• Title/Summary/Keyword: High-Strength Re-bar

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A Study on the Economic Evaluation Model of Splice of Reinforcement Bar(SD500) (초고강도 철근이음의 경제성 평가모델 개발에 관한 연구)

  • Kim, Jae-Yeob;Kim, Dae-Won
    • Journal of the Korea Institute of Building Construction
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    • v.8 no.1
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    • pp.71-76
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    • 2008
  • Recently, the high-rise apartment housings have become a prototype of the urban residential dwelling in Korea and the numbers of one have steadily been increasing. According to this trend, the strength of the construction materials is also fortified to assure the stability and durability of the buildings. Specially, Re-bar of SD500 type is largely used at the construction sites of high-rise building. This study analyzes the current usage of SD500 high-strength re-bar at domestic construction sites. Through the result of this analysis, we develop Economic Evaluation Model that measure economic efficiency of lap splice and coupler splice, which are most commonly used in connection SD500. The evaluation method was applied to construction sites in Seoul in December 2006, and the result revealed that coupler splice is relatively superior in terms of cost efficiency when the re-bar diameter is longer and the concrete strength is lower.

Pull-Out Bond Properties of Polymer Cement Coated Rebars in HSC (고강도콘크리트에서 폴리머 시멘트 슬러리 도장철근의 인발부착특성)

  • 김민호;김완기;소양섭
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.05a
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    • pp.215-220
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    • 2002
  • Epoxy-coated re-bar was partly used to the structures and put to practical use, but were not economical and appeared to have defects such as the diminishing of long term bond strength between concrete. The study of polymer cement slurry coated re-bar was started in order to complement the defect of epoxy coated re-bar, and ever since the basic properties appeared to be excellent. But, study of bond properties embedded in concrete specimens was insufficient until now. This study attempts to examine the possibility of improving the bond strength of polymer cement slurry coated re-bar between concrete specimens in accordance with ACI Code and KS Code through pull-out test of 150mm$\times$150mm$\times$150mm substrates with polymer cement slurry coated re-bar having polymer cement ratios of 50%, 75% and 100%, coating thickness 250${\mu}{\textrm}{m}$, 450 ${\mu}{\textrm}{m}$ and with curing ages of 3, 7 and 28 days. High strength concrete was designed having a compressive strength of 500kgf/cm2 as specified. Practical bond length ranges of 55 and 85mm were applied to each of specimen. The bond strength of polymer cement slurry coated re-bar using St/BA-1 and St/BA-2 was compared to that of plain re-bar. The results of this study showed that the bond strength of 55mm bond length was much higher than that of 85mm bond length.

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A Study on Benefit/Cost Analysis of Re-Bar Connection Methods for Hyper Strength(SD500) Reinforcement (SD500철근 커플러 이음의 편익/비용분석에 관한 연구)

  • Kim, Jae-Yeob;Kwon, Yeo-Wool;Kim, Jun-Young
    • Journal of the Korea Institute of Building Construction
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    • v.8 no.2
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    • pp.81-87
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    • 2008
  • High-rise building is taking a place as one of building types from apartment housings to commercial buildings. With taking in account of stability and durability, strength of used materials is increasing gradually in these high-rise buildings. According to this, frequency in use of SD500 re-bar is increasing gradually in high-rise buildings. However the study of SD500 re-bar is insufficient because SD500 re-bar started to be used for domestic buildings lately. Specially because there is no guide or study to refer to, people get into difficulties when to decide the method of re-bar connection in construction using SD500 re-bar. Accordingly in this study, it suggests the method of estimating the economical efficiency on SD500 re-bar connection, and conducts benefit/ cost analysis on lapped splice and coupler splice by applying AHP theory, and then presents its result. After to analyze re-bar diameter of D25, 29, and 32, finally we attained the result that the coupler splice is advantageous in all parts of benefit/ cost more than the lapped splice.

Development of Filler Type Mechanical Splice for High Strength Re-bar (고강도 철근용 충전형 기계적 이음장치 개발 연구)

  • Lee, Seongsoo;Chun, Homin
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.12
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    • pp.686-693
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    • 2018
  • Various types of re-bar splicing methods have been developed and applied to reinforced concrete (RC) structures in the field. According to previous studies, the coupler splice is relatively superior to the lap splice in terms of cost efficiency when the diameter or strength of the re-bar is larger or higher. This study was performed to develop a filler type mechanical splice for a high-strength re-bar (SD600) in reinforced concrete structures. The deformed re-bars were inserted into a circular steel tube coupler and high-strength epoxy filler was then injected into the coupler. The splice system was completed by hardened filler in a coupler. The epoxy filler was used as the manufactured production epoxy to conduct experiments of filler type mechanical splice specimens, and to observe the failure loads and failure aspects of the specimens. For this goal, the experiment of one-way tensile test was conducted for the epoxy filler type mechanical splices specimens according to the compressive strength of epoxy, length of coupler, and diameter of re-bar. The shape of failure of the re-bar coupler splice showed that the re-bars were pulled between the lugs of the re-bars as a result of the shear fracture of the hardened epoxy. The actual failure load of the experiment specimen was approximately 2 times higher than the expected failure load of the epoxy filler, which greatly improves the failure load of the hardening epoxy filler due to the restraint of the steel coupler.

The Technology Development for applying the High Strength Headed Deformed Bar to the Nuclear Power Plant Structures (원전구조물의 확대머리 고강도철근 적용기술 개발)

  • Lee, Byung-Soo;Bang, Chang-Joon;Lee, Han-Woo;Lim, Sang-Joon
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2013.05a
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    • pp.273-275
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    • 2013
  • If the mechanical development is applied to the Nuclear Power Plant Structures instead of the standard hook development, the problem of overcrowding re-bars in the anchorage zone can be solved and the construction quality of the concrete work will be improved. But there are some problems in applying it to the NPP structures because of the restriction on the yield strength and diameter of the re-bar. After the performance evaluation test for the mechanical development, we can develop the new design equation of the mechanical development length in order to solve the limitation and apply it to NPP structures.

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Study of application method for the Rebar Modulation of High-Strength Reinforcing Bars to the Nuclear Power Plant Structures (원전구조물 고강도철근 모듈화를 위한 적용방법 연구)

  • Lim, Sang-Joon;Lee, Byung-Soo;Bang, Chang-Joon
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2013.11a
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    • pp.17-18
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    • 2013
  • To minimize construction of nuclear facility, it is required to reduce reinforcing bar amount and solve reinforcing bar concentration and for this, it is necessary to develop appication design technology and modular of high strength reinforcing bar. Hence, KHNP reduces excessive reinforcing bar amount which can cause possibility of poor construction of concrete through design standard development and modular of nuclear facility structure using high strength reinforcing bar to raise economics and has its purpose to maintain high-level safety and durability as they are. This study is to introduce application method for the Rebar Modulation of High-Strength Reinforcing Bars to the Nuclear Power Plant Structures.

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Performance Evaluation of Welding Method for Modular of High-Strength Reinforcing Bars to the Nuclear Power Plant Structures (원전구조물 고강도철근 모듈화를 위한 용접방법 성능평가)

  • Lim, Sang-Joon;Lee, Han-Woo;Kim, Hyeong-Seob;Bang, Chang-Joon
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2013.05a
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    • pp.278-280
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    • 2013
  • To minimize construction quantity of nuclear facility, it is required to reduce reinforcing bar amount and solve reinforcing bar concentration and for this, it is necessary to develop application design technology and modular of high strength reinforcing bar. Hence, KHNP reduces excessive reinforcing bar amount which can cause possibility of poor construction of concrete through design standard development and modular of nuclear facility structure using high strength reinforcing bar to raise economics and has its purpose to maintain high-level safety and durability as they are.

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A Study on Economic Evaluation Method of Coupler Splice for High Strength(SD500) Reinforcement (SD500 고강도 철근용 커플러이음의 경제성 평가에 관한 연구)

  • Kim, Jae-Yeob;Kim, Gwang-Hee
    • Korean Journal of Construction Engineering and Management
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    • v.8 no.2
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    • pp.136-145
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    • 2007
  • This study analyzes the current usage of SD500 high-strength re-bar in domestic construction sites. Also, an evaluation method was developed to measure economic efficiency of lap splice and coupler splice, which are most commonly used in connection SD500. The evaluation method was applied to construction sites in Seoul in December 2006, and the result revealed that coupler splice is relatively superior in terms of cost efficiency when the re-bar diameter is bigger and the concrete strength is lower.

Tensile Behavior and Fracture Properties of Ductile Hybrid FRP Reinforcing Bar for Concrete Reinforcement (콘크리트 보강용 고연성 하이브리드 FRP 보강근의 인장 및 파괴 특성)

  • Park, Chan-Gi;Won, Jong-Pil
    • Journal of The Korean Society of Agricultural Engineers
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    • v.46 no.1
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    • pp.41-51
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    • 2004
  • FRP re-bar in concrete structures could be used as a substitute of steel re-bars for that cases in which aggressive environment produce high steel corrosion, or lightweight is an important design factor, or transportation cost increase significantly with the weight of the materials. But FRP fibers have only linearly elastic stress-strain behavior; whereas, steel re-bar has linear elastic behavior up to the yield point followed by large plastic deformation and strain hardening. Thus, the current FRP re-bars are not suitable concrete reinforcement where a large amount of plastic deformation prior to collapse is required. The main objectives of this study in to evaluate the tensile behavior and the fracture mode of hybrid FRP re-bar. Fracture mode of hybrid FRP re-bar is unique. The only feature common to the failure of the hybrid FRP re-bars and the composite is the random fiber fracture and multilevel fracture of sleeve fibers, and the resin laceration behavior in both the sleeve and the core areas. Also, the result of the tensile and interlaminar shear stress test results of hybrid FRP re-bar can provide its excellent tensile strength-strain and interlaminar stress-strain behavior.

Performance Evaluation Test for Applying the Mechanical Development of the High-Strength Reinforcing Bars to the Nuclear Power Plant Structures (고강도철근 기계적정착의 원전구조물 적용을 위한 성능평가실험)

  • Lee, Byung-Soo;Bang, Chang-Joon;Lim, Sang-Joon;Kim, Seok-Cheol
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2012.11a
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    • pp.197-198
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    • 2012
  • If the mechanical development be applied to the Nuclear Power Plant Structures instead of the standard hook development, the problem of overcrowding re-bars in the anchorage zone can be solved and the construction quality of the concrete work will be improved. But there are some problems in applying it to the NPP structures because of the restriction on the re-bar yield strength and diameter. After the performance evaluation test for the mechanical development, we can develop the new design equation of the mechanical development length in order to solve the limitation and apply it to NPP structures.

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