건설현장 위험요소의 관측비율분석에 의한 작업공간의 안전성 확보방안

최희복,장명훈 한국건축시공학회 2013 한국건축시공학회지 Vol.13 No.6

건설현장의 불안전하거나 위험한 요소는 안전사고를 유발한다. 안전한 작업환경을 유지하기 위해 위험요소에 대한경고나 주의 표지를 설치하고 있지만 사소한 부주의 등으로때때로 사고가 발생한다. 현장에 적재된 자재나 작업을 위해 임시 설치된 가설시설물에 의해서 경고나 주의 표지가가려지는 경우도 있으며, 작업자가 이동함에 따라 가려진표지를 파악할 수 없는 위험도 존재한다. 안전사고를 방지하기 위해 GPS나 센서를 이용하여 작업자의 위치추적방법이 연구되고 있지만 본 연구에서는 작업자의 시야를 방해하는 요소를 제거하는 것에 초점을 두고 있다. 본 연구는 적재된 자재로 인해 작업자가 위험요소를 볼 수 없는 문제가 발생할 수 있음을 확인하고, CAD를 이용하여 이를 공사계획과정에서 작업자의 시선에서 관리하는 방법을 제시한다. Unsafe and dangerous factors or environments on building construction sites often cause safety accidents. Sometimes, accidents happen despite the existence of warning and caution signs. Such warning signs are likely to behidden by stacked materials or temporary facilities on site. If workers cannot see the signs when moving or working,they could be injured, sometimes fatally. Many studies have focused on each worker’s position, and various systemshave been developed using GPS signals and sensors. This paper suggests a method for identifying the problem ofworker inability to see the unsafe factors, to manage the problem in the construction planning phase by consideringthings from the worker’s perspective. The method uses CAD software to investigate the relation between the height ofstacked materials and the visible ratio of the unsafe factor. The results of a sample project show that the changes inthe height and location of stacked materials make the site safer.

건설현장에서 외국인 노동자의 생산성에 관한 연구-생산성 및 생산성 저해인자 평가를 중심으로-

최희복,신윤석,강경인 한국건축시공학회 2005 한국건축시공학회지 Vol.5 No.1

The Korean society faces a new issue of accepting foreign workers. Foreign labors in construction industry reached about 400,000 recently. Thus they have become one of the essential resources to fill up insufficient labor supplies in construction industry. And it is important how to manage foreign labors efficiently. However there are few studies focused on this subject. Purpose of this study is to research productivity of foreign labors in the domestic construction site. So investigate the value of foreign labors. Also this study forecast elements effect on foreign labors productivity in the construction industry. And research what element is more important to improve productivity and what element is more difficult to manage. In the result, this study is expected to prospect effective method of foreign labor's management in the domestic construction industry, so contribute to utilize foreign labors more efficiently.

중소규모 건설회사 CAD 활용현황과 대학교육 방안

최희복,장명훈 한국건축시공학회 2016 한국건축시공학회지 Vol.16 No.2

A survey of small-size contractors in Jeju was conducted to investigate college graduate's CAD (computer aideddesign) competence. Most of small-size contractors use CAD softwares to review and update drawings submitted froman architect. This research analyzed the curriculum of the architectural engineering in several national universities. TheCAD classes have 4 or 6 hours per week and use AutoCAD primarily. This research proposes that a CAD class needsat least 6 hours per week, 2D drawing is the main theme in the curriculum, and exercises to make 3D models are alsoincluded in the CAD class. The improved methods, Internet cafe and real time feedbacks using a smartphone, toevaluate the reports and exercise results are necessary. 건축공학을 전공한 학생들이 보유해야할 CAD 활용능력을 조사하기 위해 제주지역 중소규모 건설회사를 대상으로 설문을 실시하였다. 소규모 건설회사는 CAD 소프트웨어를 사용하여 기존 도면을 수정하고 있다. 또한 지방의국립대학의 CAD 수업현황을 분석하였다. 기존의 CAD 수업은 4시간 또는 6시간으로 진행하고 있으며 AutoCAD를175주로 사용하고 있다. CAD 수업은 6시간 실습이 필요하다고 판단되며 2D 도면 작성이 주요 실습내용이 되어야 하고 3D 모델 작성도 수업에 편성되어야 한다. 수업의 결과를 평가할 수 있는 방법의 개선도 필요하며, 인터넷을 활용하거나 스마트폰을 이용한 실시간 피드백을 대안이 될수 있다.

순환골재 품질개선을 위한 수분흡수제어형 표면처리방법

최희복 한국건축시공학회 2015 한국건축시공학회지 Vol.15 No.6

The research, in order to enhance the quality of recycled aggregate, was carried out the quality characteristics testof the recycled aggregates by applying the four kinds of surface treatment using a colloidal suspension ofapproximately 5nm∼60nm particle size with the alkalinity of pH 10.2. The quality tests of recycled aggregate havebeen processed by specific gravity, water absorption, porosity, surface properties, and the compression and tensile tests. The colloidal suspension was coated effectively the surface of the old cement mortars of recycled aggregate with aconstant thickness by colloidal suspension is being applied to the recycled aggregate surface under constant pressureof 100kpa and then it was dried in at 60℃. The surface treatment method by the Method C out of 4 kinds of surfacetreatment improved effectively the quality of the recycled aggregates, whereby it obtained the best compressivestrength and tensile strength of the recycled aggregate concrete. 본 연구는 순환골재의 품질을 개선시키기 위해 pH 10.2의 알칼리성을 띄고 있는 입경 5nm∼60nm 정도의 40% 콜로이달 실리카 수용액을 사용하고, 4가지 표면처리방법을적용하여 순환골재의 품질 향상 시험을 하였다. 순환골재의품질시험은 비중, 흡수율, 기공률, 계면특성, 그리고 압축및 인장시험을 하였다. 100kpa의 일정 압력하에서 콜로이달 실리카 수용액이 표면에 도포되고 60℃에서 건조됨으로써 콜로이달 실리카 용액이 순환골재의 시멘트 모르타르의표면을 일정한 두께로 효과적으로 코팅되었다. 4가지 표면처리 방법 중 Method C에 의한 표면처리방법이 순환골재의품질을 효과적으로 개선시켰으며, 그로인해 순환골재콘크리트의 압축강도 및 인장강도 향상에 영향을 미친 것으로판단된다.

TPO 시트재와 유도가열공법을 적용한 고내풍성 지붕마감 공법

최희복,신윤석,최진철,이보형,강경인 한국건축시공학회 2009 한국건축시공학회지 Vol.9 No.1

Strong winds according to global warming cause the increase of the frequency and the repair cost of damaged roofs. In the United States, Factory Mutual Insurance Company(FMIC) promotes the roofing design that resists heavy wind-load, as the means of strict criteria. This fact reveals that more durable roofing system will be also required in Korea. Therefore, this study aims at developing such a system with high wind-resistance performance using Thermoplastic polyolefin(TPO) and Electromagnetic induction technology(EIT) than the previous systems. The system presented in this study consists of 4 main devices as follow; 1) a disc to fix sheets for TPO & EIT method, which can conduct structural design according to site condition, such as region, building height, and wind load. 2) a nail to have about 30% stronger lifting-up capacity than that of the previous nail. 3) a disc to fix sheets, which has triangle protuberance not to damage sheets in the repeatable wind load, and 4) a electromagnetic induction device to combine a disc and a sheet by heating uniformly and quickly adhesive agent on the disc. The results of mock-up test illustrate that the system provides wind-resistant performance to achieve satisfactorily the structural design criteria of FMIC. In addition, the system is faster, chipper, and easier than the existing system, and is expected that this roofing system can be applied to the rehabilitations of an existing as well as a new building.

순환골재 내부의 미세균열 발생형태 및 흡수 특성

최희복,김백중,강경인,이종구,Choi, Hee-Bok,Kim, Beak-Joong,Kang, Kyung-In,Yi, Chong-Ku 대한건축학회 2011 대한건축학회논문집 Vol.27 No.3

Many researchers have reported strength reduction of concrete when recycled aggregate is introduced to the mix. However, the causes of such reduction and preventive measures are yet to be established. In this study, effect of recycled aggregate on concrete is investigated by microscopic examinations of micro-cracks present in the recycled aggregate (RG) and by measuring moisture absorption rate of RG. The results showed the followings: 1) the shape and extent of micro-cracks vary by type and size of RG, 2) recycled aggregate concrete (RAC) containing RG formed the failure surface along the micro-cracks inside RG, 3) moisture uptake, which may alter local water content in wet concrete, mostly took place via micro-cracks of RG reaching depth of about 3 mm within the first 1 hr, much faster rate than that of natural aggregate of the same type. Based on the results of this study, it is recommended that the size of RG be kept less than 10 mm for production of high quality RG with a small amount of micro-cracks.

단면증대 철근콘크리트 보의 휨성능평가

최희복,고동우 한국복합신소재구조학회 2018 복합신소재구조학회논문집 Vol.9 No.3

단면증대공법은 경제성과 시공상 보편적으로 사용되는 공법으로 우리나라의 철근콘크리트 기둥을 보강하기 위한 공법으로 널리 사용되어 왔다. 이와 관련하여 단면증대된 부재의 성능에 관한 실험적 또는 해석적 연구는 수행된 사례가 있으나, 휨성능과 단면증대 부분의 표면거칠기 범위의 상관관계에 대한 연구는 수행되지 않았다. 따라서, 본 연구에서는 단면증대된 보의 휨성능을 평가하기 위해 표면거칠기의 범위를 변수로 한 단면증대보의 휨실험을 수행하였다. 그 결과는 다음과 같다. (1) 시공에서 사용되는 방법에 따라 거칠기 처리가 된 표면의 거칠기 이력을 분석한 결과 인접 산과 골의 차이는 6mm를 초과하였다. (2) 거칠기 이력이 측정된 거리가 600mm를 초과하연, 거칠기 지표는 일관된 결과를 나타내었다. (3) 표면거칠기처리를 하지 않은 보의 휨성능과 비교할 때, 표면거칠기가 된 보의 휨강성은 25%증가하고, 항복강도는 9%, 최대강도는 6%증가하였다. (4) 모든 시험편은 표면거칠기 처리의 유무에 상관없이 단면해석결과 나타난 항복강도보다 높은 강도를 나타내었다. Because of the economy and construction simplicity, Jacketing method has been widely used in strengthening RC columns in Korea. Although some studies on the performance of jacketed elements have been conducted by experimental or analytical methods, the correlation between the flexural performance and the range of the surface roughness of the jacketed element has not been performed. Flexural tests were performed to evaluate the flexural capacity of jacjeted beams. The valuable of this study is the range of surface roughness. The test results are as follows; (1) Depending on the method currently used in practice, the depth of the siphoned surface has exceeded the 6 mm shown in most drawings, (2) A stable roughness index value was obtained when the measured distance of the roughness history was more than 600 mm, (3) Compared to beams with no surface roughness, stiffness of full surface roughness treated beam increased by 25 %, yield strength of that increased by 9 %, and maximum strength increased by 6 %, (4) All specimen showed greater yield strength than the yield strength as a result of the cross section analysis, regardless of whether surface roughness was treated or not.

재생잔골재 대체율에 따른 보통 강도 콘크리트 특성

최희복,강경인 대한건축학회 2007 大韓建築學會論文集 : 構造系 Vol.23 No.2

To augment using of recycled fine aggregate, it grasp properties of required fluidity, compressive strength and tensile strength of concrete that use recycled aggregate according to replacement ratio of recycled fine aggregate and. fine/total aggregate percentage(S/A). Result of this experiment is as following. 1)In same relative water absorption, slump was high in S/A 42%, and both 47% and 52% were similar. 2)Effect that S/A gets to workability of recycled aggregate concrete appeared notedly in above S/A 47%, and was similar with normal concrete in S/A 42%. 3)According as S/A increases, decrease width of change with time, and were obvious as replacement ratio of recycled aggregate increases. 4)As relative water absorption increases, compressive strength increased. 5)Although water absorption of specimen was not influenced by kind of recycled aggregate and the replacement ratio, as fine aggregate percentage is low, absorption of specimen is high.

Surgical Correction of Medial Patellar Luxation including Release of Vastus Medialis without Trochleoplasty in Small Breed Dogs: A Retrospective Review of 22 Cases

최희복,김상연,한창훈,장아람,정혜진,황태성,이희천,황용현,이원재,이성림,이재훈 한국임상수의학회 2018 한국임상수의학회지 Vol.35 No.3

In 22 dogs with medial patellar luxation (MPL) of grade 3 or lower, resection of the vastus medialis obliquemuscle, patellar anti-rotational suture, fascia lata overlap, and tibial tuberosity transposition (TTT) were undertakento stabilize the patella without trochleoplasty. Data including signalment, clinical symptoms, details of the affectedhindlimb, preoperative and postoperative patellar luxation grades, postoperative recovery time, and postoperativecomplications were obtained from medical records. The grade of lameness was evaluated preoperatively andpostoperatively. Mean (± SEM) grade of medial patellar luxation was 2.64 ± 0.11 preoperatively and 0.2 ± 0.27postoperatively. Mean (± SEM) grade of lameness was 1.73 ± 0.27 preoperatively and 0.18 ± 0.15 postoperatively. Patellar reluxation occurred in 1 of 22 (4.5%) cases requiring additional surgery. At final follow-up, 2 of the 22 (9.0%)dogs, including one with reluxation, had occasional lameness. Client-based questionnaire results demonstrated significantimprovements in all parameters. Surgical treatment of MPL that included resection of the vastus medialis oblique withoutfemoral trochlear groove deepening improved surgical outcomes in dogs with up to grade 3 MPL.

순환골재콘크리트와 이형철근 사이의 부착성능

최희복,강경인 大韓建築學會 2008 大韓建築學會論文集 : 構造系 Vol. No.

This research is main object to study bond performance between concrete and rebar by the replacing ratio of recycled aggregate and the quality of recycled aggregate etc. as main experiment factor. Result is as following. 1) Slip was small or similar than normal concrete to replacing ratio 50% of recycled aggregate, increased in concrete that replacing ratio 100% of recycled aggregate. 2) Bond strength of recycled coarse aggregate concrete was similar with normal concrete, but bond strength of recycled fine aggregate concrete decreased according as recycled aggregate replacing ratio increases. 3) The <TEX>$\sqrt[{\tau}b]/{fck}$</TEX> of recycled aggregate concrete decreased according as relative absorption increases, and decrease tilt of <TEX>$\sqrt[{\tau}b]/{fck}$</TEX> is obvious in more than relative absorption 3. 4) According as water-cement ratio is decrescent, the <TEX>$\sqrt[{\tau}b]/{fck}$</TEX> of recycled aggregate concrete decreased, and specially it was notable in recycled fine aggregate concrete.