• 콘크리트학회논문집
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• 제16권2호
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• pp.139-146
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• 2004

최근 들어 가설기자재의 성능에 대한 관심이 급속히 증가하고 있다. 1992년 산업안전보건법에 의해 가설기자재 성능검정제도가 도입된 이후, 최근 2년간에 걸쳐 실시한 성능시험을 토대로 강제파이프서포트에 대한 기초적 연구를 진행하였다. 강제파이프 서포트의 국내 규격과 현재 연구현황을 소개하였으며, 총 849개의 시편을 대상으로 외관과 내경의 길이 및 두께조사와 겹침길이 및 평압시험과 나이프에지시험 등의 압축강도시험을 실시하였다. 전체적으로 신품과 재사용품으로 구분하여 시험을 하였으며, 재사용품의 성능감소를 파악할 수 있었다. 규격 또한 신품에 비해 많은 부분 부족한 것으로 나타났다 일반적으로 재사용품이 $10\%$ 정도의 성능감소를 파악할 수 있었으며, 이를 고려하여 볼 때 현장에서의 품질확인과 감독이 반드시 필요할 것으로 판단되었다. 우선 기초적인 결과를 토대로 통계값을 제시하였고, 각 영향요소별 세부분석은 현재 연구진행중이다. 본 연구결과는 향후 파이프서포트에 대한 기본자료로 활용될 것으로 기대된다.

• 한국안전학회지
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• 제35권3호
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• pp.43-48
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• 2020

It is considered that most of reusable pipe supports, which are used as formwork support posting at construction sites, do not meet the performance standard. Due to the use of reusable pipe supports that do not meet such performance standard the potential risk of collapse accident is increasing. Therefore, this study identifies the status of compliance with performance standard, and presents the requirements for improving quality control to prevent the collapse of pipe supports reused at the construction site. First, if the female thread of the product with no clearance and new support pin with the diameter of 12mm are replaced at the same time for use, it is considered that the performance will be improved. Second, as the quality performance during use can be improved in the case of larger thickness of inner diameter compared to the case of larger thickness of outer diameter, it is necessary to increase the inner pipe thickness greatly than the current thickness. Based on the results of this study, it is expected that the performance the reusable pipe support (V4) can be improved, if the diameter of the support pin is 12mm, the female thread has a small clearance, and the inner tube thickness is 2.3 ~ 2.7mm. In addition, it is considered that other performance improvement factors included in the study results could be used as important data for improving the performance of reusable pipe support.

• 한국안전학회지
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• 제23권4호
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• pp.67-71
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• 2008

Formwork is a temporary structure that supports its weight and that of fresh concrete as well as construction live loads. Slab formwork consists of sheathing, stringer, hanger and shore. In construction site, pipe supports are usually used as shores which are consisted of the slab formwork. In this study, compressive strength of 80 pipe supports was measured by knife edge test and plate test. Buckling load of pipe supports was analyzed by structural analysis program(MlDAS). Theoretical buckling load with/without initial deformation was got by theoretical analysis. According to these results, buckling load which was analyzed by structural analysis program(MlDAS) was larger than compressive strength of knife edge test and plate test. Theoretical buckling load without initial deformation was larger than compressive strength of knife edge test and plate test. But Theoretical buckling load with initial deformation was lower than compressive strength of knife edge test and plate test. Initial deformation equation for test method according to the pipe support length was suggested. Therefore, the present study results will be used to design the slab formwork safely.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.103-108
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• 2003

In the construction of mountain tunnels, reaction forces of the legs of steel arch supports against the ground are often expected to support the ground being excavated. In these cases, a stress concentration occurs in the ground directly under the support legs. If the bearing capacity of the ground is insufficient or displacement is not effectively constrained, the local failure of the ground under the support legs or settlement of the tunnel supports due to large deformation could result. It is therefore necessary to reinforce the support legs to reduce settlement. As a means of reducing settlement, wing-ribbed steel arch supports are well used. In this study, with the aim of finding a way to quickly reduce the settlement of steel arch support legs, effectiveness of a new type of wing ribs to reinforce steel arch supports was investigated through laboratory testing.

• 한국안전학회지
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• 제33권2호
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• pp.94-103
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• 2018

As of July 1, 2017, the method of quality management of construction equipment had been changed completely. In case of manufacturing and distributing pipe supports, the support length according to the safety certification standard shall be not more than 6 m and the compressive strength shall be not less than 40,000 N at the maximum height. However, the field tests for the quality control standard were usually performed at 3.5 m when the length of the pipe supports is 3.5 m to 4.0 m, and the compression strength was specified to be more than 35,300 N. This difference in the two standards can cause confusion in practice. In this study, the compression load of the pipe supports was tested and found to be more than 30% defective. Therefore, it is necessary to review the modification of the safety certification and quality standards to improve the standard requirements.

• 한국터널지하공간학회 논문집
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• 제20권5호
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• pp.869-886
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• 2018

록볼트는 지하굴착 중 불연속 암반을 보강하기 위하여 흔히 사용하는 대표적인 지보재 중의 하나이다. 용수가 많은 현장에서는 굴착 시공성을 개선하고 록볼트의 정착효과를 증진하기 위하여 별도의 Drain pipe 설치하게 된다. Drain pipe는 배수경로를 제공하여 작업성 개선에 효과적이지만 지반보강효과를 기대하기 어렵고, 다수 설치 시 불연속 암반의 교란을 증가시키며, 공사비 증가 요인이 된다. 이러한 문제를 개선하기 위하여 암반의 보강과 배수를 겸한 Dual purpose rockbolt (DPR)를 개발하였다. DPR은 신속하고, 경제적으로 암반의 역학적 수리적 안정성을 개선할 수 있었다. FRP (유리섬유 보강 플라스틱)와 steel을 이용한 2가지 DPR을 개발하여 역학적 수리적 성능을 검토하였고, 시공성과 안정성을 분석하였다.

• 한국농공학회지
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• 제44권4호
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• pp.107-113
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• 2002

The pipe framed and arch shape plastic greenhouse, which is the most popular greenhouse in Korea, is relatively weak in snowdrift. Reinforcement of rigid frame or column is required to reduce the damage from heavy snow in this type. But additional rigid frames or columns decrease light transmissivity or workability, and increase construction cost. So it is desirable to prepare some temporary poles and to install them when the warning of heavy snow is announced. This study was carried out to develop the temporary pole supporting system using galvanized steel pipes for plastic housing and to evaluate the safe snow load on a temporary pole. A pipe connector, which is inserted in the top of pipe used in the temporary pole and supports the center purline, was designed and manufactured to be able to carry the upper loads safely. And a bearing plate was safely designed and manufactured in order to carry the loads acting on it to the ground. When temporary poles of ${\phi}$ 25 pipe are installed at 2.4m interval, it shows that the single span plastic greenhouses with 5~7 m width are able to support the additional snow depth of 13.9~25.3 cm beyond the snow load supported by main frame.

• 대한안전경영과학회지
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• 제20권3호
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• pp.27-36
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• 2018

The steel pipe manufacturing industry deals with facilities and materials. Especially thermal facilities are close to vapor cloud explosion (VCE) and may cause secondary damage to facilities because they deal with corrosive substances such as hydrofluoric acid, sulfuric acid and acid, fire, explosion, leakage etc. It is in danger. In this study, hazard identification method was conducted using HAZOP techniques and quantitative risk analysis was conducted using e-CA, a program that supports accident impact analysis. Equipment in the influence range of ERPG - 3 was determined to be a facility requiring replacement. It was decided that neutralization is necessary using slaked lime. Based on the cost of loss, We presented the proper replacement which is the timing of the dangerous facility. As a result, It was ideal to replace the facilities with 20 years of heat treatment facilities, one year of hydrofluoric acid storage tank, 20 years of sulfuric acid storage tank, and 5 years of hydrochloric acid storage tank.

• 한국압력기기공학회 논문집
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• 제16권1호
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• pp.74-83
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• 2020

A number of so-called 'Type IV' cracking was reported to occur at the welded joints of the P91 steel or P92 steel reheat steam piping systems in Korean supercritical thermal power plants. The reheat steam piping systems are subjected to severe thermal and pressure loading conditions of coolant higher than 570℃ and 4MPa, respectively. In this study, piping analyses and design evaluations were conducted for the piping system of a specific thermal plant in Korea and suggestions were made how structural integrity could be improved so that type IV cracks at the welded joints could be prevented. Integrity evaluations were conducted as per ASME B31.1 code with implicit consideration of creep effects which was used in original design of the piping system and as per nuclear-grade RCC-MRx code with explicit consideration of creep effects. Comparisons were made between the evaluation results from the two design rules. Another approach with modification or reduction of the redundant supports in the piping systems was investigated as a tool to mitigate thermal stresses which should essentially contribute to prevention of Type IV cracking without major modification of the existing piping systems. In addition, a post weld heat treatment method and repair weld method which could improve integrity of the welded joint of P91 steel were investigated.

• Journal of Advanced Marine Engineering and Technology
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• 제39권4호
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• pp.425-431
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• 2015

선박의 LNG(liquefied natural gas) 연료 공급 시스템에서 천연가스는 $50^{\circ}C$의 온도와 35MPa의 압력을 가진 가스 상태로 기화기에서 엔진으로 이송되므로, 이러한 열 하중을 고려한 구조 안전성 평가가 반드시 필요하다. 본 연구에서는 먼저 재료에 미치는 열의 영향을 분석하기 위하여 이중 배관의 재료인 슈퍼 듀플렉스 스테인리스강의 어닐링 시간을 고려한 일축 인장 실험을 수행하였다. 또한 구조 안전성 평가를 위해, 현재 널리 사용되는 고정식 지지대를 가지는 고온-고압 이중 배관에 대한 열-구조 해석을 수행하였다. 지지대와 내관 사이의 응력 집중을 최소화하기 위하여, 내관을 따라 미끄러질 수 있는 슬라이딩 지지대의 새 형상들을 제안하였고, 열-구조 해석 결과를 통해 최적의 지지대를 제안하였다. 마지막으로 제안된 지지대를 사용한 전체 이중배관에 대한 해석을 통해 안전성을 평가하였다. 본 연구의 결과는 차후 LNG 연료 공급 시스템의 고온-고압 이중 배관 설계 시 참고자료로서 활용될 수 있으며, 이중 배관의 슬라이딩 지지대를 설계함에 있어서 그 활용가치가 있다고 판단된다.