• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.347-348
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• 2023

In construction sites, small-scale construction quantities or limited work hours below the daily work volume may occur due to on-site conditions. For small-scale quantities, the input of equipment and labor is designed based on an hourly basis in the invoice, resulting in a difference from the actual cost. In this study, we aim to explore solutions from the perspective of construction cost standards to secure appropriate construction costs for small-scale and time-limited construction sites. Firstly, to preserve the basic construction costs on-site, we established standards where half the cost would be charged for construction quantities below four hours and a full day's cost would be designed for construction quantities between four to eight hours. Additionally, realistic construction cost calculation standards are expected to be provided by realizing a surcharge rate for work hour limitations to secure appropriate construction costs.

• 한국건설관리학회논문집
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• 제9권2호
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• pp.182-189
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• 2008

국내 공공 및 민간사업에서 시행하는 건설공사에서는 원칙적으로 정부제정 건설표준품셈에 의한 노무량을 근거로 원가계산과 현장의 생산성관리를 수행하고 있다 또한 노무량은 관련 법규에 의한 산재보험료, 고용보험료, 퇴직공제부금비, 안전 관리비, 환경보전비 등을 비용으로 계상하는 근거가 되며 공사 진도관리에 있어서도 영향을 미치고 있다. 그러나 표준품셈에 의해 산정된 설계 노무량은 현장 실투입 노무량과 차이가 있는 것으로 추정되고 있으나 그동안 이를 규명한 바가 없었다. 본 연구에서는 43개 공동주택의 철근콘크리트공사에 참여하는 거푸집 형틀목공, 철근조립공, 콘크리트공의 실투입 노무량을 현장 조사하였으며 표준품셈의 산정기준과 비교하였다. 또한 실무전문가 65명을 대상으로 하는 설문조사와 현장소장과 감리단장 32명의 면담조사를 병행하여 표준품셈과 현장 실투입 노무량이 상이한 원인을 분석하였다. 본 연구에서 제시한 공동주택 건축공사의 공종별 노무량 회귀모델은 실적공사비를 적용한 공사계약관리와 더불어 실투입 노무량에 기반한 경비산정과 현장관리의 가능성과 방향을 제시하였다는 점에서 그 의미가 있을 수 있다.

• 한국건축시공학회지
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• 제23권4호
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• pp.497-508
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• 2023

Manual estimation of rebar quantities by contractors often yields discrepancies between projected and actual amounts used in the construction phase, leading to cost inaccuracies and potential logistical challenges. To address these issues, there is a clear need for a method that allows precise estimation of rebar quantities during the design phase. Such a method would enhance contractor competitiveness during project bids, promote accurate cost calculations, and avert superfluous rebar purchases on-site. Given that columns are the primary structural components in reinforced concrete(RC) buildings and necessitate considerable amounts of rebar, this study focuses on creating an automated algorithm for estimating column rebar quantities. An analysis of the accurate quantities obtained via the study and those derived from manual estimation reveals a discrepancy of 0.346 tons or 2.056%. This comparison affirms the proposed algorithm's efficacy in eliminating errors from overestimation or underestimation of rebar quantities. The practical implications of this study are significant for construction companies as it fosters efficient and precise estimation of rebar quantities, ensuring compliance with related specifications and governing regulations.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 추계 학술논문 발표대회
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• pp.67-68
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• 2016

In construction management, BoQ(Bill of Quantities) has been commonly used for the cost estimation. However, many problems have been recognized about the work items used in the BoQ that could be varied by the experience and knowledge of the estimators or the project. Also, there are lots of work items that have to be written in BoQ even though the cost proportion of those items is relatively lower than the others. In this study we consider the way how to organize optimally the work items through the analysis of case. The results of this study could be useful for improving the efficiency of preparing construction BoQ and conducting Quantity take-off in our construction management practices.

• 한국건설관리학회논문집
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• 제24권5호
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• pp.83-94
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• 2023

In order to devise a rebar usage optimization algorithm, it is necessary to calculate the exact rebar length and revise the arrangement of rebars into special lengths. However, the process of rearranging numerous rebars and manually calculating their quantities is time-consuming and requires significant human resources. To address this challenge, it is necessary to develop an algorithm that can automatically estimate the length of rebars and calculate their quantities. This study aims to create an automatic estimation algorithm that improves work efficiency while ensuring accurate and reliable calculations of rebar quantities. The algorithm considers various factors such as concrete cover, hook length, development length, and lapping length, mandated by the building codes, to calculate the quantity of rebars for wall structures. The effectiveness of the proposed method is validated by comparing the rebar quantities generated by the algorithm with manually calculated quantities, resulting in a difference rate of 1.14% for the hook case and 1.37% for the U-bar case. The implementation of this method enables fast and precise estimation of rebar quantities, adhering to relevant regulatory codes.

• 한국컴퓨터정보학회논문지
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• 제24권2호
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• pp.127-137
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• 2019

In this study, we have developed a calculation system for BIM-based quantities, 4D process, and 5D construction costs, by integrating object shape attributes and the standard classification system which consist of Cost Breakdown System(CBS), Object Breakdown System(OBS) and Work Breakdown System(WBS) in order to use for the 4 dimensional process control of roads and rivers. First, a new BIM library database connected with the BIM library shape objects was built according to the CBS/OBS/WBS standard classification system of the civil engineering field, and a integrated database system of BIM-based quantities, process(4D), and construction costs(5D) for roads and rivers was constructed. Nextly, the process classification system and the cost classification system were automatically disassembled to the BIM objects consisting of the Revit-family style elements. Finally, we added functions for automatically generating four dimensional activities and generating a automatic cost statement according to the combination of WBS and CBS classification system The ultimate goal of this study was to extend the integrated quantities, process(4D), and construction costs(5D) system for new roads and rivers, enabling the integrated use of process(4D) and construction costs(5D) in the design and construction stage, based on the tasks described above.

• 복합신소재구조학회 논문집
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• 제6권4호
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• pp.24-29
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• 2015

Bridge construction cost estimates have generally been conducted by using historial unit-price(per meter or square meter). The traditional estimating method based on unit-price references can never completely reflect the specialty of cable supported bridge. In this paper, we have developed the system for supporting the approximate construction cost and the quantity estimation based on 3D model information in the pre-project planning phase of 3-span continuous suspension bridge with 2-pylons. First of all, we'd analyzed the design information (such as structural design report, blueprint and quantity) and the real cost data from the existing suspension bridges and derived the design variables of the bridges. We developed the BIM wizard that generates a suspension bridge model parametrically based on derived design variables. The principle material quantities of suspension bridge are calculated directly from 3-dimensional bridge model built by using the BIM wizard. We have established the system that the construction cost can be estimated more specific than the traditional estimating method.

• 토지주택연구
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• 제5권1호
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• pp.41-51
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• 2014

국내 신축 공동주택 건설은 2002년 11% 이상의 증가를 기록한 후 매년 3~4% 대의 꾸준한 증가추세를 보이고 있다. 최근 공공부문의 아파트 신축공사 현장에서 폐기물 분리발주제도에 의한 최초 발주물량과 실제 발생물량의 과다한 차이가 발주자와 수급인 사이에서 빈번하게 논란을 일으키고 있다. 이에 대해서는 현장 환경관리 미흡, 초기 계약물량의 과소 등 다양한 원인이 제기되고 있으며, 특히 건설폐기물 수량 예측에 적용되는 발생원단위 기준에 대한 개정 요구가 갈수록 증가하고 있다. 대부분의 현행 원단위는 2000년대 초에 수립되어 기술 발전에 따라 새롭게 적용되는 자재와 공법으로 인한 폐기물 발생 유형과 수량의 변화를 반영하지 못한다는 문제점을 지니고 있다. 따라서 본 연구는 보다 정밀한 신축아파트 폐기물 발생 원단위를 개발하기 위한 기초작업으로서 현장의 공종별 폐기물 발생 유형과 수량 예측방법을 명확히 하고자 하였다. 이를 위해 2010년에서 2013년 사이에 착공한 신축 아파트 10개 현장의 건축공사 내역서를 확보하고, 건설폐기물 전문가와 현장 폐기물관리 담당자의 의견을 반영하여 각 내역항목에서 발생가능한 폐기물 유형과 실질 할증률을 검토하였다. 본 연구에서 가설공사부터 지급자재부문까지의 건축공사 내역항목별로 정리한 폐기물 발생여부와 유형, 수량예측 시 반영여부, 손실률 등의 자료는 향후 보다 현실적인 데이터에 근거한 간접추계방식의 원단위 개발에 기여할 것이다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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• pp.162-163
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• 2016

This paper presents a mathematical model for optimizing earthwork allocation plan that minimizes earthwork cost. The model takes into account operational constraints in the real-world earthwork such as material-type (i.e., quality level of material) and quantities excavated from cut-sections, required quality of material and quantities for each embankment layer, top-down cutting and bottom-up filling constraints, and allocation orders. These constraints are successfully handled by assuming the rock-earth material as the three dimensional (3D) blocks. The study is of value to project scheduler because the model identifies the optimal earth allocation plan (i.e., haul direction (cut and fill pairs), quantities of soil, type of material, and order of allocations) expeditiously and is developed as an automated system for usability. It is also relevant to estimator in that it computes more realistic earthworks costs estimation. The economic impact and validity of the mathematical model was confirmed by performing test cases.

• 한국BIM학회 논문집
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• 제4권4호
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• pp.13-23
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• 2014

After being introduced, Building Information Modeling (BIM) has been actively applied to the cost estimation of construction projects, and various studies on BIM based quantity take-off have been carried out. In practice, however, these calculations take considerable time, because BIM based quantity take-off is further conducted along with 2D-based quantity take-off. Studies on the quantity take-off using BIM spatial objects have been carried out on early stages of projects, but how this method differs from the existing quantity take-off method and how accurate it is in comparison have rarely been verified. Therefore, by comparing 2D based quantities with quantities through BIM spatial objects, this study analyzed the accuracy of quantity take-off using BIM spatial objects. To this end, the properties of BIM spatial objects and quantity calculable spatial types were analyzed, and existing 2D-based quantities and quantities extracted from BIM spatial objects were compared through a case study. As a result, the quantity of spatial objects found to be more by about 7.13% in 0.05% and therefore, this difference should be considered during quantity take-off using BIM spatial objects. Through the results of this study, we can improve the accuracy of quantity take-off using BIM spatial objects in the early stage of a construction project.