Quantitative Analysis on Factors Affecting Crew Productivity : Crew Size

허영기,Huh Youngki Korea Institute of Construction Engineering and Ma 2004 건설관리 : 한국건설관리학회 학회지 Vol.5 No.3

Consideration of factors driving crew productivities is imperative for accurate construction time estimation. Their impacts need to be well understood by estimators. There have been, however, little studies that quantified relationships between crew productivities and factors. This paper quantifies impacts of $^{\circ}A$ECrew size $^{\circ}\phi$ on crew productivities, for three highway concrete bridge activities, namely Column, Cap, and Deck, based on data compiled from 17 on-going highway projects in Texas State, USA. It was found that, for Bridge Deck operation, an increase of one crew-worker of formwork and rebarwork by one, leads to an increase of the productivity (cy/crew day) by 2.5 and 2.9, respectively. For the other activities, larger crew sizes did not lead to better crew productivities.

Data Collection Methodology of Activity Production Rates for Contract Time Determination

허영기,김창완,송종철,Huh Youngki,Kim Changwan,Song Jongchul Korea Institute of Construction Engineering and Ma 2004 건설관리 : 한국건설관리학회 학회지 Vol.5 No.1

Contract time determination for highway construction projects has never been easy despite considerable research efforts from academia as well as industry. High variations in crew production rates are considered one of the main barriers to accurate contract time determination. This paper presents a methodology for collecting field information on crew production rates which will help to enhance the accuracy of contract time determination for highway bridge construction. Based on a standard data collection tool developed, data on field crew production rates was collected from 14 on going projects in Texas, USA, over the past two years. The production rates based on the data collected were considered by industry practitioners to be more realistic and practical than those available to the current practices. As more data becomes available, key drivers influencing production rates could be identified and provide site personnel with a means to better plan and control production in a project specific context.

Identification of Factors Driving Crew Production Rate : Methodology and Application

허영기,Huh Youngki Korea Institute of Construction Engineering and Ma 2004 건설관리 : 한국건설관리학회 학회지 Vol.5 No.5

For accurate construction contract time estimation, few parameters are more significant than crew production rates and factors affecting the rates. However, statistical analysis techniques for finding such factors are not always simple mainly because there are many factors and the interaction between factors is not well quantitatively understood. This paper presents methodology of identifying factors driving crew production rates. The methodology is further demonstrated with representative data collected by the author from 13 on-going highway constructions. Three factors were identified as statistically significant drivers of Cap crew production rate: 'Cap Size (m3/ea)'; 'Cap Length (m)'; and 'Cap Shape (Rectangle vs. Inverted 'T')'. It was also found that the production rates are best explained by a multiple regression model with two of the drivers; 'Cap Size' and 'Cap Shape'.

Material Management Using Radio-Frequency Identification (RFID) in the Construction Industry

김창완,허영기,권순욱,Kim Changwan,Huh Youngki,Kwon Soonwook Korea Institute of Construction Engineering and Ma 2004 건설관리 : 한국건설관리학회 학회지 Vol.5 No.1

The advent of Radio Frequency Identification (RFID) technology has created new opportunities for improving the material management function in the construction industry and is starting to provide major improvements in the efficiency of the material management process. The objective of the research reported herein was to introduce the benefits of RFID technology on material management in the construction industry. RFID technology is discussed and various aspects of this technology are investigated. Potential RFID applications on material management proposed by Construction Industry Institute (CII) Breakthrough Strategy Committee (BTSC) and Fully Integrated and Automated Technology (FIATECH) are spelled out Finally, business analysis of RFID to estimate its impact is provided. It is concluded that there is a significant potential for improvement of material management function in the construction industry through the use of RFID.

텍스트 마이닝을 통한 건설 생산성 분야의 연구동향 분석 - KSCE 저널을 중심으로 -

구본길,허영기,Gu, Bongil,Huh, Youngki 한국건설관리학회 2020 한국건설관리학회 논문집 Vol.21 No.2

국토교통부가 2017년 12월에 발표한 제6차 건설기술진흥기본계획에 따르면, 건설기술혁신 등을 통해 2022년까지 건설 노동생산성을 40% 향상하는 것을 주요 목표로 하고 있다. 또한, 건설업계 및 학계에서는 건설 생산성 향상을 위해 지속적으로 다양한 연구 및 개발을 해오고 있다. 본 연구에서는 과거 15년간 대한토목학회 영문논문집에 발표된 생산성(Productivity) 관련 논문을 대상으로 어 프라이오리(A Priori) 알고리즘을 활용하여 키워드(Keyword) 간의 상관관계를 분석하였다. 분석 결과, 생산성 연구 키워드는 '작업(Work)' 및 '노무 인력(Labor)' 단어와 연관성이 매우 높은 것으로 나타났으며 생산성 영향요소, 생산성 모델과 시뮬레이션, 그리고 작업 시간에 따른 생산성 등이 키워드로 주로 연구되고 있음이 밝혀졌다. 또한, 건설기계(Machine) 혹은 장비(Equipment)와의 상관성은 낮은 것으로 분석되었다. 본 연구는 텍스트 마이닝(Text Mining)을 활용하여 국내 토목 분야에서 이루어진 생산성 관련 연구들의 개략적인 상관성과 경향을 분석하였으며, 특정 분야에서 이루어지고 있는 연구 동향 분석의 새로운 방안을 제시하였다. The relationship between keywords, found in all productivity related papers published in the KSCE journal for last 15 years, were analyzed in order to reveal a research trend in the area using text mining and A-Priori algorithm. As the results, it is found that the word of 'productivity' is most closely related to the words of 'work' and 'labor'. Futhermore, the word is somewhat related to those of 'factor', 'model', simulation', and 'work time'. It is also revealed that, on the other hand, the words of 'machine' and 'equipment' have little relationships with the keyword. This research will be a great help for academia to understand a research trend in the area of construction productivity.

초고층 공동주택 RC 공사의 생산성 및 타워크레인 가동율 분석

권지훈,허영기,Kwon, Jihun,Huh, Youngki 한국건설관리학회 2021 한국건설관리학회 논문집 Vol.22 No.1

초고층 건설사업의 골조 공사를 대상으로 철근, 형틀 작업의 생산성을 분석하고 타워 크레인(Tower Crane; TC)의 실질적인 가동률을 조사하였다. 코어부의 형틀작업 생산성은 지하 및 지상·저층부(1~7F) 구간에서는 평균 12.0~8.7(㎡/인·일)로, 기준층 구간(8~75F) 으로 진행될수록 11.9~20.7(㎡/인·일)로 생산성이 향상되는 것으로 분석되었다. 코어와 외주부의 기준층 생산성을 비교해보면 코어 생산성이 약 11% 정도 높은 것으로 나타났다. 또한 기준층의 코어부위 철근작업 생산성(평균 1.02 ton/인·일) 대비 외주부(기준층 평균 1.12 ton/인·일)의 생산성은 대략 9.6% 높은 결과가 도출되었다. 또한, TC 세 대의 평균 가동률은 63.49%로 조사되었으며, 비가동일의 원인으로는 우천 6.1%, 강풍 6.1%, 휴무 17.8%, TC 인상작업 5.8%, 기타 고장 및 수리 등이 0.07% 인 것으로 분석되었다. 이러한 연구결과는 향후 초고층 골조 공사의 공정을 계획하고 관리함에 있어 유용한 자료가 될 것으로 기대된다. The productivity of rebar-work and form-work was analyzed with data collected from an actual high-rise construction project, and the actual utilization rates of three tower cranes were also investigated. It was found that the average productivity of the form-work increased from 12.00~8.71(㎡/man·day) in the underground and above-ground/lower-floor to 11.94~20.73(㎡/man·day) in the standard floor. Comparing the productivity of core area to outer, the former was found to be about 11% higher. Moreover, the rebar-work productivity of the outer area(1.12 ton/man·day) was approximately 9.6% higher than that of the core area for the standard floor. The average utilization rates of three TC were surveyed to be about 63.49%, and it was revealed that rainy weather(6.1%), strong winds(6.1%), holidays(17.8%), TC lifting work(5.8%), and other failures and repairs(0.07%) were the causes of non-operation. These research results are expected to be beneficial data in planning and managing the process of high-rise RC construction works in the future.

"MODEL SPELL CHECKER" FOR PRIMITIVE-BASED AS-BUILT MODELING IN CONSTRUCTION

권순욱,프레데릭 보쉐,허영기,Kwon Soon-Wook,Frederic Bosche,Huh Youngki Korea Institute of Construction Engineering and Ma 2004 건설관리 : 한국건설관리학회 학회지 Vol.5 No.5

This research investigates a Modeling Spell Checker that, similarly to Word Spell Checker for word processing software, would conform as-built 3D models to standard construction rules. The work is focused on the study of pipe-spools. Specifically pipe diameters and coplanarity are checked and corrected by the Modeling Spell Checker, and elbows are deduced and modeled to complete models. Experiments have been conducted by scanning scenes of increasing levels of complexity regarding the number of pipes, the types of elbows and the number of planes constituting pipe-spools. For building models of pipes from sensed data, a modeling method, developed at the University of Texas at Austin, that is based on the acquisition of sparse point clouds and the human ability to recognize geometric shapes has been used Results show that primitive-based models obtained after scanning construction sites can be corrected and even improved automatically, and, since such models are expected to be used as feedback control models for equipment operators, the higher modeling accuracy achieved with the Modeling Spell Checker could potentially increase the level of safety in construction. Result also show that some improvements are still needed especially regarding the co-planarity of pipes. In addition, results show that the modeling accuracy significantly depends on the primitive modeling method, and improvement of that method would positively impact the modeling spell checker.

중소규모 공동주택의 건축심의 한계점 분석

안지호,구본길,류종우,허영기,Ahn, Jiho,Gu, Bongil,Ryu, Jongwoo,Huh, Youngki 한국건설관리학회 2022 한국건설관리학회 논문집 Vol.23 No.6

A single-person-house-holder has been increased since 2000s in South Korea, which led to high demands for small and medium-sized new houses requiring municipal architectural review committee consideration. And it has been argued recently that there are many limitations in the review system. Comprehensive expert surveys and interviews were conducted and the results were analyzed using the AHP to explore limitations in B city. The analysis with the data of 27 survey responds found that 'Related ordinance itself', 'Committee members limitation', and 'Absurdity on administrative procedure' are problematic in order of priority. It is also revealed that architects and administrative officials have different thoughts on the seriousness of those. The results of this study are expected to be used as basic data on studies for improving the system.

AHP와 로지스틱 회귀분석을 이용한 공동주택개발사업 참여의사결정 모델 및 영향요인 분석

김기신(Kim, Ki-Shin),김수용(Kim, Su-Yong),김대영(Kim Dae young),허영기(Huh, Youngki) 대한건축학회 2016 大韓建築學會論文集 : 構造系 Vol.32 No.1

Large portion of apartment projects are initiated and conducted by developers together with contractors in Republic of Korea. Contractors therefore surely need to have great knowledge about feasibility analysis in order to make right decision on whether or not participate in a project proposed by a developer. However, few contractors have such skill and insight in reality and make the judgement mainly based on experience and intuition of their top management. A decision making model was developed that can be used easily and practically by contractors. Furthermore 109 real project cases were applied into the model and found that the model could help to make right decision with reliability of as high as 85.3 percent. Using scatter plots and logistic regression analysis, a few drivers affecting the decision were also found, namely, "project site", "basic plan", "economic feasibility", "salability’. The results will be a great interest for anyone who wants to make right decision with relatively small efforts.

건설기계 시공능력 산정에 관한 연구 : 작업효율 중심으로

박희성(Pakr Hee-Sung),한예령(Han Ye Lyeong),허영기(Huh Youngki),안방률(Ahn Bang Ryul) 대한토목학회 2008 대한토목학회논문집 D Vol.28 No.1D

건설기계는 건설사업의 성공적인 수행을 위한 중요한 요인이다. 그리고 건설기계에 소요되는 비용이 건설공사비에서 차지하는 비중이 크다. 따라서 건설기계 비용의 산정은 건설계획 단계에서 중요한 업무이다. 이를 위해서 우리나라는 표준 품셈에 제시된 건설기계 시공능력 산정식을 이용하여 건설기계의 시간당 작업량을 계산하는 방식을 활용하고 있다. 그러나 건설기계의 성능은 개선되고 있으나 시공능력 산정식에서 활용되고 있는 작업효율은 이를 반영하지 못하는 실정이다. 이에 본 연구는 유압식 백호, 로우더, 덤프트럭을 대상으로 현장실사를 통해 작업효율을 실측하였다. 그 결과 백호와 로우더는 현재 활용중인 작업효율보다 현장실사 값이 높게 나타났으며, 텀프트럭은 낮게 나타났다. 본 연구결과를 바탕으로 건설기계의 작업효율 표준 산정식에 대한 정의가 수립되어야 하며, 체계적이고 장기적인 조사를 거쳐 작업효율의 개정이 필요할 것으로 사료된다. Heavy equipment is a very important factor for successful construction implementation. Also, the cost for heavy equipment is a major part of construction cost. Therefore, the estimation of equipment cost is a critical job in the construction planning phase. A formula for production rates shown in 'Standard Unit Labor' has been used to estimate construction equipment capability per hour and cost. Although the performance of equipment has been improved, the efficiency rates in the formula are not updated lately. Therefore, this research performed several site visits to measure construction equipment working time and then calculates the efficiency rates for hydraulic backhoe, loader, and dump truck. The results show that the measured efficiencies of backhoe and loader are higher than current ones and vice versa for dump truck. This research proposes the needs for a standardized calculation formula and systematic and long-term data collection and measurement for updating efficiency rates for heavy equipment.