• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3477-3483
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• 2015

A reasonable process for the activity duration estimation is required for the successful construction management because it directly affects the entire construction duration and budget. However, the activity duration is being generally estimated by the experience of the construction manager. This study suggests an estimation model of construction activity duration using neural network theory. This model estimates the activity duration by considering both the quantitative and qualitative elements, and the model is verified by a case study. Because the suggested model estimates the activity duration by a reasonable schedule plan, it is expected to reduce the error between planning duration and actual duration in a construction project.

• Korean Journal of Construction Engineering and Management
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• v.7 no.4 s.32
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• pp.100-108
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• 2006

Non-working days affected by weather conditions of the construction-sites have been estimated without proper data. They are usually estimated based on project engineer's own experience and intuition. As a result, they cause not only economic loss to time-adjustment but also conflicts among project participants. It becomes more difficult to predict the weather nowadays than before due to tendency of recently weather change. Therefore, this paper presents an improved estimation method for non-working days, which could minimize estimation errors. The estimation method is developed based on analysis of regional characteristics and weather conditions which affect project duration.

• Korean Journal of Construction Engineering and Management
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• v.6 no.1 s.23
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• pp.58-64
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• 2005

We should consider climatic factors influencing construction works in order to estimate construction time correctly. This study is to analyze climate elements affecting construction duration and to calculate non-working days far Inchoen territorial region. Through surveying literatures and examining several existing criteria we suggest a Proper criteria for each climate elements which would be used for estimating non-working days. The criteria is made on the raw climate data of Meteorological Administration during the last 30 years(1974-2003) far Incheon region. In case of rainfall, it is estimated as non-working days when daily precipitation is expected more than 10mm, its number of days for Incheon is 29 days. In case of low temperature, the number of non-working days for the concrete works(its criteria be below $4^{\circ}C$ average) and the finishing works(below $0^{\circ}C$ average) is 97 days, 52 days, respectively. In case of high temperature, it is three days when daily highest temperature is expected going over $32^{\circ}C$

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.681-686
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• 2004

수공구조물의 설계를 위해서는 해당 수공구조물의 중요도에 따른 설계빈도 및 설계유량과 설계수위 등의 설정이라는 과정이 필요하다. 설계빈도는 하천설계기준에 제시되어 있는 바와 같이 시설물의 입지조건과 중요도에 따라 기준이 제시되어 있으며 설계홍수량은 확률강우량을 기초로 한 설계강우를 결정하고, 결정된 설계우량에 의한 유출량의 산정작업이 필요하다. 이와 같은 설계수량의 산정에 있어서 설계강우의 지속기간 설정은 매우 중요한 작업이다. 일반적으로 동일한 설계빈도의 홍수량은 지속기간에 따라 많은 차이를 보이고 있다. 따라서 설계강우의 지속시간 설정은 매우 중요한 설계인자가 되므로 본 연구에서는 IHP유역인 위천유역을 대상으로 최근 권장되고 있는 설계강우의 지속시간 선정을 위한 개념인 임계지속기간을 산정하여 임계지속기간에 영향을 미치는 수문인자들에 대해 살펴보고자 한다. 본 연구에서는 IHP 유역인 위천 유역(동곡 외 4개 소유역)을 대상으로 설계홍수량의 첨두유출량이 최대로 발생하는 강우지속기간을 임계지속기간으로 설정하였으며, 설계홍수량의 산정시 설계강우로부터 홍수량을 산정하기 위한 일련의 절차에서 이용되는 각종 수문요소들, 즉 강우시간분포와 유효우량 산정방법, 유출모형 그리고 면적의 변화에 따른 임계지속기간의 변화를 연구하였다. 본 연구에서는 임계지속기간의 개념을 고려할 설계강우의 지속기간을 산정하기 위해 필요한 각 수문요소별 산정방법은 국내 자료로부터 제안된 방법을 우선 사용하였으며, 임계지속기간의 개념에 따른 설계강우의 지속기간 산정을 위해 확률강우량 산정, 강우의 시간분포(Huff 분포, Yen & Chow의 삼각형 분포), 유효우량 산정방법(AMC-II, AMC-III, CN37), 대표단위도와 6가지 합성단위도법을 적용하였다. 산정 된 결과로부터 임계지속기간 산정에 영향을 주는 각 수문인자 중 강우시간분포와 유효우량 산정방법 그리고 유출모형에 대해 자자 검토하였으며, 최종적으로 면적에 따른 임계지속기간과 유출량의 변화를 검토해 보았다.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.444-447
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• 2006

Construction managers need to pay a close attention to the resource utilization in order to deliver the construction project successfully. Construction scheduling is crucial for resource control in that it provides information when and how much to bring down work force to sites. In scheduling, activity duration is projected based on the productivity of historical data or the intuition of scheduler. This paper studies the opportunity of applying cost-based productivity for estimating activity duration. For cost-based productivity, the cost of resource is used as an input and the work quantities as an output. Out of historical data, regression model has been developed to understand the validity of applying cost-based productivity in projecting activity duration. The result of study will work as a prerequisite for implementing the environment of database-based construction scheduling.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.5
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• pp.601-608
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• 2021

Recently, despite a decrease in the number of working days and an increase in the number of non-working days due to an increase in the abnormal climate and the revision of the Labor Standards Act, a standard construction period reflecting this has not been established. For this reason, even if the appropriate construction period is calculated at the site, there is a situation where delays occur due to unexpected circumstances. Therefore, this study proposes a method of calculating the number of non-working days for railway bridgework construction that reflects changes in construction conditions and climate change and reflects this to railway bridgework construction, and the number of working days was calculated. As a result, the number of non-working days by region and month in Korea was derived, and through this, the necessity of regulations and standards for appropriate construction periods reflecting regional characteristics and characteristics of each construction type was presented.

• Korean Journal of Construction Engineering and Management
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• v.10 no.2
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• pp.26-33
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• 2009

The required level of detail in scheduling depends on the stages in the construction life-cycle. The objective of this study is to provide a Standardized Schedule Model (SSM) with an aim to facilitate the estimating of construction duration in the planning stage. The SSM modularizes work items; establishes relations between preceding and succeeding activities; and calculates approximate construction duration. The estimated duration of the SSM was compared with the detailed duration from the commercial scheduling tool using actual work activities. The difference showed to be ranged between -3.1% and +15%, which demonstrates that the SSM can be feasibly applied to the approximate estimation of construction duration.

• Korean Journal of Construction Engineering and Management
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• v.13 no.3
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• pp.67-77
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• 2012

O Having a highly reliable plan for the process and estimating an accurate construction period during the early stages of a construction project can prevent falsifying the plan and reduce the occurrence of construction delays. Moreover, it allows a succession of swift and accurate decisions to happen. The difficulty in obtaining an accurate estimate of the construction period is especially prominent in high-rise building projects because the works involved are very complicated and costly. As such, it is important that research is done to find out the impacts a reliable plan and good estimate of the construction period can bring with regards to the monthly work efficiency and success of a high-rise building project. However, due to the difference in climatic conditions at high altitude and surface level, the current way of calculating work efficiency in a typical project is inaccurate for a high-rise building project. With that, this paper aims to compute the work efficiency with height, taking into consideration the change in climatic elements at different working heights. A comparison of the results according to the climatic features of each city can also be done in this paper. According to the results calculated in work altitudes, the work efficiency in Busan falls the most. On the other hands, the work efficiency in Seoul falls the least. The reason these results are shown is the influence of wind speed at high altitude. The estimation of work efficiency at high altitude would be used for estimating construction period, feasibility studies, and selecting a city of high-rise building projects.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.394-397
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• 2004

Working-day calculation with weather factors of construction-site has estimated wethout proper data. They usually estimate it with their own experience and intuition. It causes not only economic loss to time-adjustment but also conflict with each participants. Moreover, weather estimation becomes worse than before, due to tendency of recently weather change. So, in this paper we present optimal estimation method as assessment by period of the arithmetical mean methods. For that, we analyse characteristic of the regions and weather change of temperature and rainfall which affects time.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.558-561
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• 2007

In this paper, non working day for the construction project in Cheongju and Chungju region considering weather condition was estimated. In Cheongju region, non working day for outside and half outside work was 157days and for interior work 144days. For Chungju region, non working day for outside and half outside work was 160days and for interior work 144days. Non working day affected by temperature was 144 days at both Chungju and Cheongju. Non working day due to low temperature was 109 days and it due to high temperature was 45 days for Choengju. In Chungju, it was 11Sdays for cold weather, while it due to hot weather was 29 days.Non working day due to rainfall was 23 days at both region. To reduce the deviation between estimated non working days and measured ones, proper selection of the duration is required.