• Title/Summary/Keyword: Construction defects

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차량탑재형 고소작업대의 재해분석을 통한 취약 구조부의 안전성 향상 방안에 관한 연구 (A Study on the Safety Improvement of Structural Weakness Using Accident Analysis for Vehicle-Mounted MEWP)

  • 유용태;서수은;유희재;강경식
    • 대한안전경영과학회지
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    • 제19권1호
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    • pp.15-25
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    • 2017
  • The findings were summarized as follows. The safety check by manufacturer showed that 6 of 13 companies are over the average occurrence of defects. It was expected that there would be a difference between manufacturing technology capability and production system of each manufacturer. Consequently, manufacturers should institutionally improve and strengthen certification items for the upward standardization of safety certification before factory. Second, the safety check by year showed that the results of this study accord with those of previous studies on defect time. Consequently, manufacturers should classify the 3-year-old equipment for vehicle-mounted MEWP into a special check subject to do a nondestructive test according to proven results, and also reflect the test in a safety test system to do regular preventive activities of equipment defects. Third, the safety check by part showed that the boom and outrigger parts of vehicle-mounted MEWP have the most defects. Stress concentration resulted in defects as the boom part was most frequently operated in the structural parts for a real work. To prevent this, it is suitable to improve the hardness of boom materials. The outrigger part needs improvement in safety devices with materials. As an outrigger supports the overturning moment of equipment, it is most affected by its load based on the operating radius, resulting in fatigue crack.

조선시대 심의 구성이론 (The Construction Theary of "Sim-Eui" During Chosun Dynasty)

  • 조효춘
    • 복식
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    • 제27권
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    • pp.27-40
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    • 1996
  • 1.It was recorded at "Dong Gook Tong Gam" of King "Jang Soo" that "Sim-Eui" in Korea was first introduced from China at the reign of King, "Moon Ja"(491,A.D), Go Goo Ryo. 2."Sim-Eui" was worn as a mourning dress during the period of "Go Ryo" and as a concanical robe of Confucian, a ceremonial dress at home and for the rules of etiquettes during Cho Sun Dunasty. 3.Several theories about the construction and the using services of "Sim-Eui" are obseved and summerized. 4.Mr. Kyu-soo Park gives a definition to "Sim-Eui" as a Fortune of Heaven & Earth, the Constellation of the Cosmic Dual Forces, the Revolution of the Four Seasons, a dignified mien & the Way of a Man of Virtue and Virtue of the golden Mean. 5.I observed the concrete measurements of the each parts of "Sim-Eui" by the construction method of Kyu-Soo Park. 6.The Symbolic Meaning following the Idea of Mr. Chung, Hyun. describes well the line of thinking in our nation, and Idea of Loyalty & Filial Piety, a Man of Virtue and the Virtue of the Golden Mean. 7.As described above, I dare insist of the fact that the Construction Theory of "Sim-Eui" by Kyu-Soo Park during the letter period of Chosun Dynasty is full of our national manners and cus-toms with symbolizing meaning, construction's exquisiteness, clothes' materials and it's size most suitable to our people, to the exclusion of the defects in "Sim-Eui" of China and Japan.

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3차원 유한요소해석을 이용한 고층 무량판 슬래브 구조물의 부등축소량 및 장기처짐 예측 평가 (Prediction and Evaluation on Inequality Shortening and Long-term Deflection of High-rise Flat Plate Structure using 3D Finite Element Analysis)

  • 심학보;박순전
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2020년도 봄 학술논문 발표대회
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    • pp.159-160
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    • 2020
  • Flat plate structures are designed in the form of long span due to the development of construction materials and the improvement of construction technology. However, a high-rise structure of a flat plate of 50 less floors is constructed without detailed review of the inequality shortening, long-term deflection of the slab, and cracks. Therefore, it is possible to examine the case of defects in the structure due to deformation and damage of non-structures such as crack and leak, deflection of the door frame, and deformation of equipment ducts. In this study, it is a high-rise structure, and the inequality shortening and long-term deflection of the slab of the flat plate structure were evaluated through finite element analysis, and it was confirmed that prior precision analysis and correction during construction is necessary.

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DEMATEL 기법을 적용한 건설재해 영향요인 구조 분석 (An Analysis of the Causal Relations of Factors Influencing Construction Accidents Using DEMATEL Method)

  • 김동욱;정윤호;홍민기;장현승
    • 한국건설관리학회논문집
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    • 제21권1호
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    • pp.87-98
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    • 2020
  • 2017년 기준 우리나라 산업재해자의 28.5%, 산업재해 사망자의 29.6%를 건설업이 차지하고 있어 국내 산업재해율 저감을 위해서는 건설업에 대한 우선적 재해 저감 방안 모색이 필요하다. 따라서 본 연구는 건설재해 영향요인을 대상으로 DEMATEL 분석을 수행하여 이에 기반한 건설재해 저감을 위한 개선방향을 제시하였다. 분석 결과, 4M 요인 중에서는 관리적요인, 4M 세부요인 별로는, 작업자의 개인특성, 기계·설비의 자체결함과 미흡한 기계·설비의 점검 및 정비, 미흡한 안전관리 계획, 부적절한 작업지시가 가장 근본적이고 중심적인 요인인 것으로 분석되었다. 본 연구는 DEMATEL 분석을 통해 건설재해 개선방향 수립을 위한 기초자료로 활용이 가능할 것으로 판단된다.

모듈러건축 공법의 공장제작과정 개선을 위한 M.E.P.시스템 외주제작 적용에 관한 연구 (A Study on Outsourcing Application of M.E.P. System for Manufacturing Process Improvement of the Modular Construction Method)

  • 최준석;이재수
    • 한국건축시공학회지
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    • 제18권3호
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    • pp.277-283
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    • 2018
  • 공기를 획기적으로 감소시킬 수 있는 모듈러건축으로 유사 모듈이 반복되는 공동주택을 건설하는 안에 대해 현행의 시공방법을 고찰한 결과 설비시스템에서 개선할 점을 발견하고, 그 방법으로 공장제작과 현장설치부분을 구분해서 살펴보고 현재 모듈러생산사 실무진의 의견과 종합건설사 기술담당자의 의견으로 그 가능성을 확인하고자 했으며 그 과정에서 제기된 문제에 대해 원천적인 관점에서 쉽게 풀어나갈 수 있는 방법으로 유리한 설계안을 제안하였고, 접속부위의 누수하자와 같은 고질적 문제점에 대한 대안을 기재하였다.

공동주택 외부 석재마감에 따른 창호주위 누수방지에 관한 연구 (A Study in the Water Leakage Prevention around the Windows with the Stone Materials in the Apartment House)

  • 윤홍중;조태제
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2006년도 추계 학술논문 발표대회 논문집
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    • pp.117-121
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    • 2006
  • This study intends to suggest the effective methods for water leakage prevention around the windows in stone works to up-grade the outdoor public space that has been taken much portion of apartment housing trends. The subjects of the study was selected among the domestic subcontractors of stone works. There are four methods for water leakage prevention around the windows; Firstly, the painting water-proof method after the masonry. Secondly, the urethane water-proof method after galvanizing panels on the gap. Thirdly, the separation method between stone and substructure and the last one is water-proof method that they put some water-proof screen between stone and substructure with the EPDM sheets. According to the analysis of the water-proof effects, constructability and planning, we could approach to conclusion that the most influent items to the water-leakage are the filling material's deformation, the state of oxygenation and deterioration of work skill. Among the water-proof methods in construction the EPDM sheet is most excellent water-proof method to meet the technical conditions. However, we have to apply it to stone works as a water-proof method for the decrease of the leakage defects after standardizing the materials, test and construction skill because there are many work skills according the subcontractors.

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Tack Coat Inspection Using Unmanned Aerial Vehicle and Deep Learning

  • da Silva, Aida;Dai, Fei;Zhu, Zhenhua
    • 국제학술발표논문집
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    • The 9th International Conference on Construction Engineering and Project Management
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    • pp.784-791
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    • 2022
  • Tack coat is a thin layer of asphalt between the existing pavement and asphalt overlay. During construction, insufficient tack coat layering can later cause surface defects such as slippage, shoving, and rutting. This paper proposed a method for tack coat inspection improvement using an unmanned aerial vehicle (UAV) and deep learning neural network for automatic non-uniform assessment of the applied tack coat area. In this method, the drone-captured images are exploited for assessment using a combination of Mask R-CNN and Grey Level Co-occurrence Matrix (GLCM). Mask R-CNN is utilized to detect the tack coat region and segment the region of interest from the surroundings. GLCM is used to analyze the texture of the segmented region and measure the uniformity and non-uniformity of the tack coat on the existing pavements. The results of the field experiment showed both the intersection over union of Mask R-CNN and the non-uniformity measured by GLCM were promising with respect to their accuracy. The proposed method is automatic and cost-efficient, which would be of value to state Departments of Transportation for better management of their work in pavement construction and rehabilitation.

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2D 도면 및 3D 모델링 분석을 통한 실내 건축공사 품질향상 체크리스트 제안 (Quality Improvement Checklist for Interior Construction based on 2D Drawings and 3D Modeling Analyses)

  • 이준섭;방홍순;김옥규
    • 한국건축시공학회지
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    • 제22권3호
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    • pp.269-280
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    • 2022
  • 건축물이 재산적 가치가 높아지면서, 국내외에서 실내 건축공사를 많이 하는 추세이다. 실내 건축공사는 물량 산출 및 적산까지 가능한 BIM 모델링의 기술까지 발전하였다. 실제 현장에서 반영하기에는 부담스러운 금액과 공정에 따라, 2D 도면과 3D 모델링을 통하여 진행하는 추세이다. 2D 도면과 3D 모델링은 서로 장단점이 존재하여 각 실내 건축공사에서는 시공 중 하자가 발생하고 있다. 실질적인 문제를 파악하기 위해 실내 건축공사의 현장 문제점, 2D 도면분석, 3D 모델링 분석, 사전 리스크 요인을 분석하였다. 문제점 분석 결과 1) 발주자와 의사소통 2) 노무자와 의사소통 3) 도면의 이해 등 여러 가지 문제점이 도출되었다. 본 연구에서는 이를 해결 할 수 있는 실내 건축공사 품질향상 체크리스트 제안을 하였다.

편중 가능한 사장교 가설용 데릭 크레인을 이용한 합성형 복합 사장교 시공 단계 해석 (Construction Stage Analysis of Hybrid Composite Cable-Stayed Girder Bridge Using Eccentrically Loaded Derrick Crane)

  • 박태균;김문겸;원종화
    • 대한토목학회논문집
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    • 제30권3A호
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    • pp.277-286
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    • 2010
  • 케이블을 이용하여 장경간을 필요로 하는 교량의 시공은 일반적으로 불완전 한 구조계인 교량의 선단에 데릭 혹은 무한궤도 크레인을 설치하여 수상 및 육상으로 이송되는 교량 상판을 리프팅하여 시공하게 된다. 이와 같은 경우 일차적으로 과도한 크레인의 자중으로 인하여 불완전한 구조계에 결함을 발생시킬 수 있으며, 또한 하부 수송으로 인한 추가 비용 및 공기를 소요하게 된다. 본 연구에서는 이러한 기존 시공방법을 개선하고자 개발된 교량 일 측에 편중 가능하고, 가동 붐을 설치하여 후방 이송 자재를 시공 지점으로 운반, 가설이 가능한 데릭 크레인의 시공 단계를 정의하여 수치해석을 수행하였다. 데릭 크레인의 하중 재하 점을 고정부 4점으로 단순화하였으며, 가동 붐의 수직/수평 회전 범위를 고려하여 반력을 산정하였다. 또한 크레인의 '휴지' 및 '작업 중'의 단계로 나누어 가동 붐 및 강형, PC Slab에 의하여 발생하는 휨 모멘트를 시공단계에 반영하였다. 본 연구에 고려된 데릭 크레인은 접속교를 통한 육상 작업으로 시공 기간 및 비용을 줄일 수 있으며, 크레인 자체의 작은 중량으로 시공 중 재하 하중 감소를 꾀할 수 있다.

경조직 결손 수복을 위한 새로운 생체재료의 개발 (The Development of New Biomaterial for Restoration of Hard Tissue Defects)

  • 김영균
    • 대한치과의사협회지
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    • 제36권4호통권347호
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    • pp.289-295
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    • 1998
  • Toothash and Plaster of Paris(Calcium sulfate) mixture have been studied for development of new biomaterial since 1992. I have performed the experimental and clinical study for evaluation of biocompatibility and possibility of bony defect reconstruction and clinical application. These materials are biocompatible, osteoconductive and resorbable. Main component of toothash is hydroxylapatite. In the future, I will perform the systematic construction of material and additional research.

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