• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2519-2528
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• 2013

The standard of estimate is being used as basic material for appropriating construction expenses of public institutions and private institutions. The present thesis aims to propose a new form of a standard of estimate and a calculation method of work amount of equipment by targeting a representative construction type selected at river reservation work. The present thesis expects that the convenience of users can be expanded by improving applicability of a standard of estimate and simplifying a calculation process of work amount of equipment in a process planning stage so that the provision of work crew lineup information and daily productivity information is possible by a standard of estimate. In case of river conservation work, because the variables called work conditions act very largely, there exists much difficulty for generalizing productivity information and work amount of equipment, but if its accuracy could be enhanced by improving continuous productivity information and work amount information of equipment, the simplification of process planning establishment and cumulative process through a standard of estimate would be possible.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.2
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• pp.97-111
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• 2012

This study aims to find a proper construction cost calculation method by comparing unit prices of cost estimate in landscape construction among other public ordering construction projects. There were 7 out of 12 items from the actual work cost in the first half of 2011 were compared. The 12 items were classified as landscape Architectural construction and the 7 items were the approximate standard. As applied construction types, the comparable 35 items out of the 80 actual work cost items applied to 5 sites were compared to the unit price of the standard quantity per unit in March 2011, which was the approximate standard. Actual construction rate of the 7 items in the category of landscape sector was 104.86% for each item and 92.09% as a total construction cost. The high actual construction rate was caused by the high rate of seed spray depending on the status of applying rocks. However, there were more fundamental reasons for the cost generated from aslope treatment for grass and seed spray. So, it requires more detailed regulations on the modification factors for each soil type, the standard and needs to improve theillogical standard quantity per unit system. Actual construction rate of the 35 items in the applied sectors of civil engineering and architecture was 78.65% for each item and 71.31% (70.17%) as a total construction cost. This shows that actual unit cost cannot reflect actual cost structurally and standard quantity per unit system lacks practicality in terms of construction due to thelabor force. 85.1~91.2 % actual construction rate announced by the Ministry of Land and Maritime Affairs referred to the newly switched items. So the result was estimated as actual construction rate. This requires supplementation after verification in order to make the actual work cost produce at a proper rate. Also, standard quantity per unit system needs complementation with these actual data and so on.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.11-12
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• 2011

The Construction Standard Production Unit(CSPU) has been used for the standard cost estimate in public and private construction projects. However, It is difficult to reflect the various site attributed variation in productivity using existing CSPU. The reason is that a criteria which site should be selection for enactment and/or revision of CSPU is not established. This study aims to provide essential data to be used for analyzing the labor factors in a way to secure efficiency and reliability of CSPU.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.187-189
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• 2011

Standard production unit system has been used as accumulated standard for the cost estimation of public construction projects. However, it is difficult to estimate reasonable cost due to adaptation of a uniform standard and reflect changes in the technology. The purpose of this study is to provide basic data for improvement of standard production unit system through the identifying problems and analysing its influence on enactment and/or revision work of standard production unit system.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.488-493
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• 2013

Accurate initial cost estimates are essential to effective management of construction projects where many decisions are made in the course of project management by referencing the estimates. In practice, the initial estimates are frequently derived from historical actual cost data, for which standard distribution-based techniques are widely applied in the construction industry to account for risk associated with the estimates. This approach assumes the same probability distribution of estimate errors for any selected estimates. This assumption, however, is not always satisfied. In order to account for the probabilistic nature of estimate errors, an alternative method for measuring the risk associated with a selected initial estimate is developed by applying the Bayesian probability approach. An application example include demonstrates how the method is implemented. A hypothesis test is conducted to reveal the robustness of the Bayesian probability model. The method is envisioned to effectively complement cost estimating methods that are currently in use by providing benefits as follows: (1) it effectively accounts for the probabilistic nature of errors in estimates; (2) it is easy to implement by using historical estimates and actual costs that are readily available in most construction companies; and (3) it minimizes subjective judgment by using quantitative data only.

• Journal of the Korea Institute of Building Construction
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• v.8 no.1
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• pp.37-42
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• 2008

As use of construction equipment has been increasing continuingly, the proportion of equipment expense to the total construction cost has become higher. However, there is a difference between the equipment expenses section in 'Poom-Sam' and practical data, because 'Poom-sam' does not consider non-working days due to weather conditions, legal holidays and management conditions. Therefore, 'Poom-Sam' does not present a reasonable standard for estimating construction equipment expenses. In this study, to estimate realistic construction equipment operating hours, firstly, construction equipment was classified according to work, and weather conditions, in which each work could not be executed, were established. Then, weather data on Seoul and Busan($2004{\sim}2006$) and legal holidays were analyzed to suggest annual standard operating hours. The annual standard operating hours of earthmoving & excavating, compaction, and drilling equipment was estimated to be 1,430 hours, and lifting equipment, concrete paving equipment, asphalt paving equipment, concrete equipment, and crushing & conveying equipment were estimated to be 2,124 hours, 1,156hours, 1,188hours, 1,688hours, and 2,152hours respectively.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.234-235
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• 2019

In the stacking and pitching items of the stone masonry and demolition process presented by 2018's standard of estimate, 7 estimating standards are presented according to the depth of masonry stone, and it is presented that the quantity per unit increases as the depth of masonry stone grows. As a result of analyzing the application status in the site, it is shown that 2 or 3 stones are mainly used according to the stone sizes regardless of the depth of masonry stone, and that as the size of the stone becomes larger, the quantity per unit decreases due to the size per square meter(㎡). Also, in most of sites, machine construction is mainly carried out by excavators with clampers attached to them. Therefore, in the 2019's application standard of estimate, it is analyzed that the size is simplified down to 3 sizes reflecting the site application status and that it is revised as a standard reflecting the result that as the stone size becomes bigger, the productivity increases.

• Land and Housing Review
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• v.8 no.3
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• pp.189-200
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• 2017

The work breakdown structure and the precedence relations by work activity are very important because they are the basic data for estimating the construction duration in the construction work. However, there is no standard to accurately estimate the construction duration since the size of the school facilities construction is smaller than the general construction work. Therefore, some schools are unable to open in March or September and the delay of the construction duration can cause damage to the students. To solve this problem, this study developed a work breakdown structure of school facilities construction work and analyzed the precedence relations by work activities. The work breakdown structure of the school facilities construction is composed of three steps. The operations corresponding to level 1 and level 2 are as follows. (1) 2 preparatory work categories; preparation period and temporary construction. (2) 17 architectural work categories; temporary construction, foundation & pile work, reinforced concrete work, steel roof work, brick work, plaster work, tile work, stone work, waterproof construction, wood work, interior construction, floor work, metal work, roof work, windows construction, glazing work and paint construction. (3) 7 mechanic and fire work categories; outside trunk line work, plumbing work, air-conditioning equipment work, machine room work, city gas plumbing work, sanitation facilities and inspection & test working. (4) 4 civil work categories; wastewater work, drainage work, pavement work and other work. (5) 1 landscaping work categories; planting work. The work breakdown structure was derived from interviews with experts based on the milestones and detailed statements of existing school facilities. The analysis of precedence relations by school facilities work activity utilized PDM(Precedence Diagramming Method)which does not need a dummy and the relations were applied using FS(Finish to Start), FF(Finish to Finish), SS(Start to Start), SF(Start to Finish). The analysis of this study shows that if one work activity is delayed, the entire construction duration may be delayed because the majority of the works are FS relations. Therefore, it is necessary to use the Lag at the appropriate time to estimate the standard construction duration of the school facility construction. Lag is a term used only in the PDM method and it is used to define the relationship between the predecessor and the successor in creating the network milestone. And it means the delay time applied to the two work activities. The results of this study can reasonably estimate the standard construction duration of school facilities and it will contribute to the quality of the school facilities construction.

• Journal of the Korea Institute of Building Construction
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• v.16 no.2
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• pp.133-140
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• 2016

The amount of labor input in a construction project is used as source data to estimate construction cost and to understand the productivity of the construction industry. However, there is a significant difference between the standard of estimation and the actual amount of labor input, and a plan is needed to resolve this problem. For this reason, to establish a system with which the actual amount of labor input can be inputted in a more accurate and simpler manner, a new method is proposed in this study. In the new method, a digital pen is used to minimize the difference from traditional handwriting on paper using a pen, and eliminate the redundant input of information. This study is expected not only to reduce the actual amount of labor input but also to contribute to the productivity of construction cost estimate through the sharing or utilization of the information on the web.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.202-203
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• 2020

Unlike price calculation by cost accounting, which categorizes costs into material costs, labor costs, and miscellaneous expenses to determine the construction budget price, construction cost calculation based on Construction Standard Unit Prices utilizes unit prices extracted from market prices of items from projects already completed to estimate costs of similar construction projects. Although unit price information is collected through construction site surveys to revise these construction standard unit prices every year, but due to the limitations of the site survey method, it is difficult to quickly implement the rapid changes in the construction methods and market prices. As such, an important issue that arose was the identification of work items whose prices need urgent revision. This study conducted research on factors that need to be considered when developing online survey system for monitoring construction site market prices. This study is expected to enhance convenience for users, and provide an efficient data collection and management system for administrators.