Journal of the Korea Institute of Building Construction (한국건축시공학회지)

The Korean Institute of Building Construction (한국건축시공학회)
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Analysis of Impact Factors for the Improvement of Conceptual Cost Estimation Accuracy for Public Office Building

공공청사 개산견적 정확도 향상을 위한 공사비 영향요인 분석

  • Jo, Yeong-Ho (Department of Architectural Engineering, Gyeongsang National University) ;
  • Yun, Seok-Heon (Department of Architectural Engineering, Gyeongsang National University)
  • Received : 2021.09.09
  • Accepted : 2021.10.01
  • Published : 2021.10.20
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Abstract

A Conceptual cost estimate, which is computed in the preliminary step of a project, is important for decision-making by a contractor in terms of the project budget, economic feasibility and validity analysis, and alternative comparisons. Therefore, a high error rate of a prediction model for a conceptual cost estimate can lead to various problems including excessive project expenditures and a delayed break-even point. this study proposed optimal impact factors by configuring quantitative impact factors computable in a preliminary step in various cases(combinations of impact factors). subsequently, the accuracy of different cases was comparatively analyzed by using the cases as input values of a prediction model using regression analysis. when the optimal combination of impact factors proposed in this study and other combination of impact factors were applied to the prediction model, the regression analysis-based prediction model exhibited 0.2-4.7% improvements in accuracy, respectively. the optimal combination of impact factors proposed in this study improved the accuracy of the prediction model of a conceptual cost estimate by removing unnecessary impact factor.

본 연구는 기획단계에서 이루어지는 개산견적 예측 모델의 정확도를 향상시키기 위하여 최적의 영향요인 조합을 제시하였다. 이에 기획단계에서 활용이 가능한 정량적인 영향요인을 선정하여 상관분석 통해 공사비에 가장 많은 영향을 주는 연면적을 중심으로 8가지의 영향요인 조합을 설정하였다. 8가지 영향요인 조합을 다중회귀분석을 통하여 VIF계수 및 회귀식을 도출하였다. VIF계수를 통해 연면적, 건축면적과 층 영향요인을 함께 사용할 경우 연면적과 건축면적 두 영향요인 간의 종속적인 관계를 확인하였다. 이에 독립성이 예측 모델 정확도의 관계를 분석하기 위하여 실 사례 프로젝트 10건을 회귀식에 대입하여 정확도를 분석하였다. 분석결과, 독립성이 확보가 안 된 영향요인 조합은 다른 영향요인에 비해 정확도 떨어지는 것을 확인할 수 있다. 따라서 최대한 많은 영향요인을 활용하는 것보다 최적의 영향요인 조합을 선정하는 것이 예측 모델의 정확도를 향상시킬 수 있다고 판단되며, 본 연구에서는 연면적과 건축면적을 활용하였을 경우 정확도가 가장 높은 것을 확인하였다.

Keywords

Acknowledgement

This work is supported by the Korea Agency for Infrastructure Technology Advancement(KAIA) grant funded by the Ministry of Land, Infrastructure and Transport(Grant 21AATD-C163269-01).

References

  1. Ahn YS, Song KR, Heo JM. Improving the accuracy of screening of cost estimating in early construction project phase. Journal of the Architectural Institute of Korea Structure & Construction. 2003 Nov;19(11):133-40.
  2. Song KR. A study on the standard for approximate quantity of framework of apartment housing for using scatter diagram & heptagram method. Journal of the Architectural Institute of Korea Structure & Construction. 2005 Oct;21(10):167-74.
  3. Kim SM, Cho JH, Lee JS, Chun JY. Cost estimating model of structural elements using approximate quantity survey in preliminary building design phase. Journal of the Architectural Institute of Korea Structure & Construction. 2009 Dec;25(12):155-64.
  4. Park UY, Kim GH. A study on predicting construction cost of apartment housing projects based on support vector regression at the early project stage. Journal of the Architectural Institute of Korea Structure & Construction. 2007 Apr;23(4):165-72.
  5. Son JH, Kim SK, Kim JO. A study on the analysis and estimation of the construction cost by using artificial neural network in the btl projects for educational facilities. Journal of the Architectural Institute of Korea Structure & Construction. 2008 Jun;24(6):136-42.
  6. Yim JH, Park JM, Kim OK. Cost estimating method of public building construction through construction scale. Journal of the Korea Institute of Building Construction. 2015 Jun;15(3):307-16. https://doi.org/10.5345/JKIBC.2015.15.3.307
  7. Jung SH, Gwon OB, Son JH. A study on the analysis and estimation of the construction cost by using deep learning in the smart educational facilities -Focused on planning and design stage-. Journal of the Korean Institute of Educational Facilities. 2018 Nov;25(6):35-44. https://doi.org/10.7859/kief.2018.25.6.035
  8. Kim KH, Park CS, Chang SH. Web-based cost planning program for high-rise office building. Korean Journal of Construction Engineering and Management. 2005 Apr;6(2):69-79.
  9. Seo JK, Kim SM, Cho JH, Chun JY. Supporting model of cost planning using case-based reasoning in pre-design phase-focused on the case of public office building. Journal of the Architectural Institute of Korea Structure & Construction. 2010 Apr;26(4):159-68.
  10. Son BS, Park MS, Lee HS, Lim DH. Analysis the schematic cost estimating model based on quantity variation in building projects using the case study. Journal of the Architectural Institute of Korea Structure & Construction. 2008 Jun;24(6):109-18.
  11. Park YJ, Won SK, Han CH, Lee JB. A study on 3D BIM collaborative approximate estimating model of structural work for apartment projects. Journal of the Architectural Institute of Korea Structure & Construction. 2011 Jun;27(6):123-30.