• Title/Summary/Keyword: Reinforcing bar cutting

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Stress Distribution Characteristics of Surrounding Reinforcing Bars due to Reinforcing Bar Cutting in Penetration (관통부의 철근 절단으로 인한 주변 철근의 응력분포 특성)

  • Chung, Chul-Hun;Moon, Il Hwan;Lee, Jungwhee;Song, Jae Cheol
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.42 no.6
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    • pp.775-786
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    • 2022
  • In the plant structures including nuclear power plants, penetrations are frequently installed in walls and slabs to reinforce facilities during operation, and reinforcing bars are sometimes cut off during concrete coring. Since these penetrations are not considered at the design or construction stage, cutting of reinforcing bar during opening installation is actually damage to the structure, structural integrity evaluation considering the stress transition range or effective width around the new penetration is necessary. In this study, various nonlinear analyses and static loading experiments are performed to evaluate the effect of reinforcing bar cutting that occurs when a penetration is newly installed in the shear wall of wall-type building of operating nuclear power plant. In addition, the decrease in wall stiffness due to the installed new penetration and cutting of reinforcing bars is evaluated and the stress and strain distributions of rebars around penetration are also measured.

A Study on Reinforcing Effect of Multi-Bar Spring Nailing (다철근 스프링 네일링 공법의 보강효과 검토에 관한 연구)

  • Lee, Choong-Ho;Jung, Young-Jin;Kim, Dong-Sik;Chae, Young-Su
    • Journal of the Society of Disaster Information
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    • v.3 no.2
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    • pp.147-169
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    • 2007
  • This study investigates the reinforcing effects of the Multi-bar Spring nails with respect to the conventional Soil-nails in artificial slopes. Based on wide experience related to design and construction, soil nails have been widely applied to reinforce slope in the world. Multi-bar spring nails are one of the improved soil nailing methods. These method maximizes bending, shearing, pull-out resistance for those multi-nails, not unit nail, that are inserted in the borehole using special spacer at regular intervals. In addition, because cutting plane is confined effect resulting from a pressured plate at the end of the nails with compression spring equipment, slope stability is secured using MS-nailing method. Analyzing bending, pull-out, shearing condition of MS-nail, it was examined throughly elastic region, load transfer capacity, reinforcing effect on cutting plate of MS-nails. In addition, Pilot and laboratory tests, numerical analysis were carried out to verify the superiority of MS-nailing method. In case, MS nailing method is applied to reinforce artificial slope, it was analyzed that bending, pull-out, shearing resistance was increased more than existing nailing method was applied. In this study, it was shown that surface failure was more or less prevented using MS-nailing method, confining effect on cutting plane using spring stuck to flexible equipment.

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Heated temperature and Range of the Oxy-acetylene Cutting Reinforcing Bar by Simulation and Experiment (시뮬레이션과 실험에 의한 산소절단기 절단시 철근의 수열온도 분포)

  • Kim, Bong-Joo;Kim, Jae-Hun;Cho, Byoung-Hoo
    • Journal of the Korean Society of Hazard Mitigation
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    • v.8 no.2
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    • pp.1-5
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    • 2008
  • The object of this experimental and simulation study is to find out heated temperature and range from the Oxy-acetylene cutting point of reinforcing bars (D10, D13, D16, D19, D22, D25 for each cases of SD3O and SD40) in room temperature ($20{\sim}22^{\circ}C$). This cutting is under the condition that a skilled worker cut one bar per a time. The results are these. 1. The temperature of the point 1 of reinforcing bars cut with Oxy-acetylene cutter is over 700$^{\circ}C$ under 1000$^{\circ}C$, but the temperature of the point 2 of reinforcing bars cut with Oxy-acetylene cutter is under 200$^{\circ}C$ 2. The temperature of the point that is apart 2cm from Oxy-acetylene cutting point is not over 200$^{\circ}C$, so reinforcing bars has not transform to be brittle. The results of simulation for temperatures of the each point apart from Oxy-acetylene cutting point is similar to upper experimental results.

A Study on the Improvement of Reinforcing Bar Detailing (국내 철근공사 배근상세 개선방안에 관한 연구)

  • Park, U-Yeol;Kim, Baek-Jung;Jung, Hyun-Ok;Yun, Seok-Heon;Cho, Hun-Hee;Kang, Kyung-In
    • Journal of the Korea Institute of Building Construction
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    • v.8 no.1
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    • pp.83-90
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    • 2008
  • The reinforcing steel process is composed of the development of placing drawing, cutting and bending, and the placement and fabrication of the reinforcement, and is participated in by reinforcement detailer, the fabricator and placer. Because the reinforcing steel process-from estimating and rebar detailing, to production, material tracking, billing, and general accounting-is conducted by many participant, reinforcement details based on building code and reinforcing bar detailing standards are essential. The process, however, holds some problems. Building code has been revised recently, and the utilization of placing drawings was proved to be low, and the reinforcement estimating in early stage of the process is below what is required for placement. Therefore, in this study, a survey was conducted to the reinforcement detailer, the fabricator and placer of domestic construction industry. According to the analysis of the survey, the reinforcement details on site was not standardized. The improvement in reinforcing steel detailing standards was sought by analyzing the results of the survey including reinforcement constructability.

Developing an Automatic System for Making a Placing Drawing and Quantity taking-off Cut and Bent Re Bar with Work Zone Information (설치 위치 정보를 포함한 배근시공상세도 작성 및 가공철근 자동 물량산출 시스템 개발)

  • Park, Hyeon-Yong;Lee, Seung-Hyun;Kang, Tai-Kyoung;Lee, Yoo-Sub
    • Journal of the Korea Institute of Building Construction
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    • v.8 no.2
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    • pp.63-70
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    • 2008
  • Reinforcing steel work plays an important role in terms of its structural performance or weight of construction cost for reinforced concrete structures. Precise estimation of re-bar quantity gives a basis for managing the reinforcing steel work effectively. However, the estimation process is still performed ineffectively based upon the expert's experience or manpower in spite of the advanced technology or improvement efforts. Therefore, the purpose of this research is to develop a prototype system for taking-off the quantity of reinforcing steel bars quickly and accurately in an order consistent with the specific members identified on the drawings. An estimate algorithm considering the connection, settlement and coating thickness of re-bars was suggested regarding to their replacement conditions which places more emphasis on constructibility. Also, this system produces the shop drawings automatically with the calculation results with work zone information.

Experimental Study on the Precast Concrete Joint using Re-bar Debonding and Cutting Technique (철근 비부착 및 절단 기법을 사용한 PC 접합부의 실험적 연구)

  • Yi, Waon-Ho;Moon, Jung-Ho;Lee, Yong-Jae;Lee, Han-Jun
    • Journal of the Korean Society of Hazard Mitigation
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    • v.2 no.4 s.7
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    • pp.131-141
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    • 2002
  • Precast concrete (PC) panels are often used as retaining walls to support soil pressure. In such a case, the panels should be connected at the location where PC panels meet with a buttress. However, it is not easy to provide enough development length for the reinforcing steels due to the limited width of the buttress. If it happens, the width of buttress should be increased as large enough although it is not desirable. The critical section required for providing the development length is always located where the flexural moment is maximum. Thus it is the place the buttress width ends. Also it is the place that the reinforcing steels stressed to maximum. However, it is possible to make differentiate between the maximum moment location and the most stressed location of reinforcing steels. It means that the most stressed location of reinforcing steels, the critical section, can be moved to the other place where the moment is not maximum. New critical location will have less moment than that of buttress width ends. In consequence, the development length would be longer than that of the typical way of construction. Debonding or cutting technique make it possible to reduce the moment strength of a section. Therefore reinforcing steels are debonded or cut to have a desired flexural strength at a desired place. In this study, five test specimens in full scale were erected to examine the effects of critical section movement in PC panel joints. Test parameters were the length variations of debonded and cut reinforcing steels. The test results showed that the debonding or cutting technique could be used to lengthen the development length in the joint of PC panels.

Comparison of the quantity estimations from the design phase and the settlement quantities of construction field to improve the extra rates of bar splice (철근 이음조정률의 개선을 위한 설계견적 수량과 현장시공 정산 수량의 비교분석 연구)

  • Kim, Sang-Yeon;Choi, Bo-Mi
    • Land and Housing Review
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    • v.8 no.4
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    • pp.257-266
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    • 2017
  • LH has been using ultra high strength reinforcing bars (SD500 and SD600), since 2011. Such a change requires an adjustment of the old extra rates of bar splice to reflect use of ultra high strength reinforcing bars, as these rates had been set based on SD400 bars. It is particularly difficult to calculate precisely rebar lap-splice locations for large areas, such as those in apartment buildings. This research aims to adjust the extra rates of bar splice to reflect a reasonable rate; the rebar lap-splice length is not an exact estimation, but instead, an extra rates of bar splice is set and the rebar lap-splice length is increased by 2% (D 10) - 7% (025) depending on the bar size. The subjects of this study are LH apartments undergoing frame construction. We studied the quantity estimations from the design drawings, and analyzed the settlement quantities of construction field. The results of the study revealed that, when each of the quantities are analyzed, consider adjusting the extra rates of bar splice of some rebar to 1% - 3.5%. This was caused by an overuse of reinforcing bars in onsite construction and the use of supporting bars that have not been reflected in the documents, among other reasons. Based on the results of our study, an improvement plan for the current extra rates of bar splice seems to be necessary, cutting or raising the rate depending on the analysis of the data. Through this study, we expect to contribute to the calculation of reasonable construction costs, improvements in the quality of rebar work, and improvements in the capacity of design techniques for apartment buildings.

A Basic Study of Automatic Rebar Length Estimate Algorithm of Columns by Using BIM-Based Shape Codes Built in Revit (BIM 기반 형상코드를 이용한 기둥 철근길이 자동 산정 기초 연구)

  • Oh, Jin-Hyuk;Kim, Sun-Kuk
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2023.05a
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    • pp.21-22
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    • 2023
  • In reinforced concrete constructions, reinforcing bar generates more CO2 per unit weight than other construction materials. In particular, cutting and bending rebar is the main source of rebar waste in the construction industry. Rebar-cutting waste is inevitable during the construction of a reinforced concrete structure since the rebar is not manufactured as designed. Large amounts of waste can be avoided by utilizing optimal cutting patterns and schedules. This research provides a fundamental analysis of the automatic calculation of column rebar length using BIM-based shape codes to minimize cutting waste to near zero. By employing this approach in practice, it is possible to minimize the rate of rebar-cutting waste, reduce costs, shorten construction duration, and reduce CO2 emissions. In addition, the development of this research will serve as a clue for the development of BIM-based rebar layout automation algorithms.

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Developing An Automatic System for Quantity Taking-off Cut and Bent Re-Bar and Making a Placing Drawing (가공철근 물량산출 및 배근시공상세도 작성시스템 개발)

  • Park, Hyeon-Yong;Lee, Seung-Hyun;Kang, Tai-Kyung;Lee, Yoo-Sub
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • 2007.11a
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    • pp.358-363
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    • 2007
  • Reinforcing steel work plays an important role in terms of its structural performance or weight of construction cost for reinforced concrete structures. Precise estimation of re-bar quantity gives a basis for managing the reinforcing steel work effectively. However, the estimation process is still performed ineffectively based upon the expert's experience or manpower in spite of the advanced technology or improvement efforts. Therefore, the purpose of this research is to develop a prototype system for taking-off the quantity of reinforcing steel bars quickly and accurately in an order consistent with the specific members identified on the drawings. An estimate algorithm considering the connection, settlement and coating thickness of re-bars was suggested regarding to their replacement conditions which places more emphasis on constructibility. Also, this system produces the shop drawings automatically with the calculation results.

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Reinforcing Effect and Behaviors of Root-Pile in Heavy-Duty Direct Shear Test (대형직접전단시험에 의한 뿌리말뚝의 거동 및 보강효과)

  • Han, Jung-Geun;Jang, Sin-Nam
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.5 no.3
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    • pp.23-30
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    • 2002
  • In recently, using of steel reinforcements by reinforcing materials of the reinforced earth, micro-pile and root-pile etc,. is wide-spreading in the stabilizing control of cutting and embankment slopes, but the failure mechanism of reinforced earth as well as the effect of insert angles or types of reinforcement and others are not defined clearly. In this study, therefore heavy-duty direct shear tests were exercised on the reinforced soil and the non-reinforced soil, which was executed for research on the interaction of soil-reinforcement and theirs behavior. The hardness and softness and the standard sands were used for modeling of reinforced soil, the material constants for the computer simulation were estimated from the results of CD-Test. The effects of reinforcing and of friction increasing on the softness, area ratio of reinforcements is equal, were the better than them of the hardness, as well the reinforcing effects of shear strength without regard to the area ratio is much the same at $10^{\circ}$, insert angle of reinforced bar, differ from them of the existing study. Then, the results of numerical analysis showed that the behavior of reinforcements displayed bending resistance and shear resistance at $15^{\circ}$ and $30^{\circ}$, respectively. Also, the state of strain transfer was observed and the behavior of resistance mechanism on reinforcements presented almost the same them of landslides stabilizing pile.