BIM기반 확률론적 GMP 산정방안에 관한 연구

고건호 ( Go Gun-ho ),김정훈 ( Jin Zheng-xun ),김현주 ( Kim Hyun-joo ),현창택 ( Hyun Chang-taek ) 한국건축시공학회 2018 한국건축시공학회 학술발표대회 논문집 Vol.18 No.1

Recently, CM at Risk delivery system(CM@R) that could solve the problems of Design Bid Build delivery(DBB) system has been emerging. In the CM@R delivery system, the contractor negotiates for a maximum guaranteed price(GMP) with the client at the design stage, and the contractor carries out the construction within the GMP. In CM @ R, the construction company with expertise in construction participates from the design stage to reflects the construction know-how in the design. On the other hand, the modification design frequently occurs due to the change of the construction cost when negotiating the GMP. In addition, uncertainties are inherent in the GMP calculation because the calculation is based on unfinished drawings and documents. This study proposes a probabilistic GMP estimation method applying MCS to the BIM - based cost prediction model, in order to extract the accurate quantity information when estimating the GMP and to cope with the change of the construction cost inherent in uncertainty.

CM at Risk를 적용한 공동주택의 확률론적 초기 GMP 산정방안

현창택,고건호,김정훈,Hyun, Chang-Taek,Go, Gun-Ho,Jin, Zhengxun 한국건축시공학회 2018 한국건축시공학회지 Vol.18 No.3

In the DBB delivery system, the design stage and the construction stage are separated. Because of this, design changes frequently occur, and problems such as construction cost overrun, schedule delay, and quality deterioration happen as well. Recently, in the construction industry CM at Risk(CM@R) delivery system, which can systematically solve the above-mentioned problems of DBB delivery system, meet various demands of clients, and overcome the limited cost and period. In the CM@R delivery system, the contractor negotiates for a maximum guaranteed price(GMP) with the client at the design stage, and the CM performer carries out the construction within the GMP. However, uncertainties are inherent in the GMP calculation because the calculation is based on unfinished drawings and documents. In this study, a Probabilistic Earlier GMP Calculation Method by combining a probabilistic tool of Monte Carlo simulation with a case based reasoning is proposed so that the uncertainty in GMP calculation is reflected. After the earlier GMP is calculated, a process to calculate the $2^{nd}$ GMP at the time of around 80 % of detailed deign and to negotiate with the client to fix the final GMP is proposed. The Probabilistic Earlier GMP Calculation Method is verified through the case study. In this study, researchers set the range of GMP through the proposed probabilistic GMP calculation and tried to reduce the risk through negotiation between the client and the CM performer. The proposed method and process would contribute to the successful introduction of CM@R in Korea. 현재 DBB 발주방식에서는 설계단계와 시공단계가 분리되어 있어, 잦은 설계변경이 발생하고 있다. 아울러 공사비초과, 공기지연 및 품질저하를 야기하는 문제점들을 초래하고 있다. 최근에 발주자의 다양한 요구, 제한적인 예산 및 공기 등의 제약조건에 대응할 수 있는 발주방식인 CM@R 발주방식이 대두되고 있다. CM@R 발주방식에서는 설계단계에서 발주자와 협의하여 GMP를 정하고, GMP 내에서 CM수행자가 책임을 지고 공사를 수행하는 방식이다. 그러나 CM@R 특성상 완성되지 않은 도서를 기준으로 GMP를 산정하기 때문에 불확실성이 내재되어 있다. 본 연구에서는 GMP 산정시 불확실성을 고려하기 위하여, CBR를 이용한 공사비 예측 및 MCS를 적용한 확률론적 초기 GMP 산정방안을 제시하였으며, 초기 GMP 산정 이후 사업진행에 따라 GMP 협의를 수행할 수 있는 프로세스를 제시하였다. 사례연구 및 검증을 통하여 확률론적 초기 GMP 산정방안을 검증하였다. 본 연구에서는 제시된 확률론적 GMP 산정방안을 통하여 GMP의 범위를 설정하고 발주자와 CM수행자가 협의을 통해 리스크를 줄임으로써, CM@R의 성공적인 국내 도입에 일조하고자 하였다.

hBN의 첨가량에 따른 Si₃N₄/hBN 세라믹의 재료특성 및 마이크로 홀가공 유용성 평가

박귀득,고건호,이동진,김진형,강명창,Park, Kwi-Deuk,Go, Gun-Ho,Lee, Dong-Jin,Kim, Jin-Hyeong,Kang, Myung Chang 한국기계가공학회 2017 한국기계가공학회지 Vol.16 No.1

In this paper, $Si_3N_4/hBN$ ceramics with various hexagonal boron nitride (hBN) contents (0, 10, 20, or 30 wt%) were fabricated via spark plasma sintering (SPS) at $1500^{\circ}C$, 50MPa, and 10m holding time. The material properties such as the relative density, hardness, and fracture toughness were systematically evaluated according to the hBN content in the $Si_3N_4/hBN$ ceramics. The results show that relative density, hardness, and fracture toughness continuously decreased as the hBN content increased. In addition, peak-step drilling (with tool diameter $500{\mu}m$) was performed to observe the effects of hBN content in micro-hole shape and cutting force. A machined hole diameter of $510{\mu}m$ (entrance) and stable cutting force were obtained at 30 wt% hBN content. Consequently, $Si_3N_4/30wt%$ hBN ceramic is a feasible material upon which to apply semi-conductor components, and this study is very meaningful for determining correlations between material properties and machining performance.

hBN의 첨가량에 따른 Si3N4/hBN 세라믹의 재료특성 및 마이크로 홀가공 유용성 평가

박귀득(Kwi-Deuk Park),고건호(Gun-Ho Go),이동진(Dong-Jin Lee),김진형(Jin-Hyeong Kim),강명창(Myung Chang Kang) 한국기계가공학회 2017 한국기계가공학회지 Vol.16 No.1

In this paper, Si3N4/hBN ceramics with various hexagonal boron nitride (hBN) contents (0, 10, 20, or 30 wt%) were fabricated via spark plasma sintering (SPS) at 1500°C, 50MPa, and 10m holding time. The material properties such as the relative density, hardness, and fracture toughness were systematically evaluated according to the hBN content in the Si3N4/hBN ceramics. The results show that relative density, hardness, and fracture toughness continuously decreased as the hBN content increased. In addition, peak-step drilling (with tool diameter 500 μm) was performed to observe the effects of hBN content in micro-hole shape and cutting force. A machined hole diameter of 510 μm (entrance) and stable cutting force were obtained at 30 wt% hBN content. Consequently, Si₃N₄/30wt% hBN ceramic is a feasible material upon which to apply semi-conductor components, and this study is very meaningful for determining correlations between material properties and machining performance.

밀링기반 마찰교반접합 신기술동향: 공구, 장비 및 응용부품

노중석(Joong-Suk Noh),김주호(Ju-Ho Kim),고건호(Gun-Ho Go),강명창(Myung-Chang Kang) 한국기계가공학회 2013 한국기계가공학회지 Vol.12 No.6

Friction stir welding (FSW) is a solid state joining technique that has expanded rapidly since its development in 1991 and has numerous applications in a wide variety of industries. This paper introduces the basic principles of friction stir welding (FSW) and presents a survey of the latest technologies and applications in the field. The basic principles that are discussed include the terminology, tool/workpiece processes, FSW merits and process variants. In particular, the process variants including the rotation speed and traveling speed are discussed, which include the defect-free zone in an oxygen free copper and Al alloy, respectively. Multiple aspects of the FSW machine are developed, including a horizontal 2D FSW machine and a hybrid complex FSW machine. The latest applications are introduced, with an emphasis on the recent advances in the aerospace, automotive, and IT display industries. Finally, the direction for future research and potential applications are examined.

알루미늄 합금 AA6061-T6와 Silafont-36의 이종금속 레이저 용접부 특성에 관한 연구

현준혁(Jun-Hyeok Hyun),신태우(Tae-Woo Shin),장복수(Bok-Su Jang),김상호(Sang-Ho Kim),고건호(Gun-Ho Go),김태영(Tae-Young Kim),고진현(Jin-Hyun Koh) 대한용접·접합학회 2017 대한용접·접합학회지 Vol.35 No.5

The characteristics of dissimilar weld metals between AA6061-T6 and Silafont-36 by laser welding were evaluated in terms of bead shape, microstructure, EDS analysis, hardness, and tensile strength. Laser power of 3.0, 3.5, 4.0kW and incident angle of 15, 20° were employed to make dissimilar weld metals. Bead shape of weld metal with 3.5kW, 15° was most stable. Microstructure of dissimilar weld metals consisted of columnar dendrite in area adjacent to fusion line and equiaxed dendrite in center of weld metal. Also, Mg2Si and α-AlFeMnSi were precipitated in weld metal. Microstructure in HAZ of Silafont-36 consisted of eutectic Al-Si, Mg2Si, and β-Al5FeSi. Si contents of weld metal made with 4.0kW, 15° were very high. And Mg contents of weld metals were relatively low because of vaporation of Mg. Hardness of weld metal made with 4.0kW, 15° was very high because Si contents of that were high. In tensile test, Specimens were fractured in Silafont-36 or weld metals. The fracture in base metals was due to low tensile strength of Silafont-36, and the fracture in weld metals was due to undercut or porosity.