Application Of The Work Breakdown Structure In Determining Cost Buffers In Construction Schedules

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The paper presents methods of determining the location of cost buffers and corresponding contingency costs in the CPM schedule based on its work breakdown structure. Application of correctly located cost buffers with appropriately established reserve costs is justified by the common overrunning of scheduled costs in construction projects. Interpolated cost buffers (CB) as separate tasks have been combined with relevant summary tasks by the start–to–start (SS) relationship, whereas the time of their execution has been dynamically connected with the time of accomplishment of particular summary tasks using the “paste connection” option. Besides cost buffers linked with the group of tasks assigned to summary tasks, a definition of the cost buffer for the entire project (PCB) has been proposed, i.e. as one initial task of the entire project. Contingency costs corresponding to these buffers, depending on the data that the planner has at his disposal, can be determined using different methods, but always depend on the costs of all tasks protected by each buffer. The paper presents an exemplary schedule for a facility and the method of determining locations and cost for buffers CB and PCB, as well as their influence on the course of the curve illustrating the budgeted cost of work scheduled (BCWS). The proposed solution has been adjusted and presented with consideration of the possibilities created by the scheduling software MS Project, though its general assumptions may be implemented with application of other similar specialist tools.

1. H. Kerzner, Project management. A systems approach to planning, scheduling and controlling, Van Nostrand Reinhold, New York, 1984.

2. D. Y. Kim, S. H. Han, H. Kim, H. Park, Structuring the prediction model of project performance for international construction projects: A comparative analysis, Expert Systems with Applications 36 (2) (2009) 1961–1971.

3. A. Czarnigowska, A. Sobotka, Time–cost relationship for predicting construction duration, Archives of Civil and Mechanical Engineering, 13 (4) (2013) 518-526.

4. M. M. Fouladgar, A. Yazdani-Chamzini, E. K. Zavadskas, Risk evaluation of tunneling projects, Archives of Civil and Mechanical Engineering, 12 (1) (2012) 1-12.

5. O. Kapliński, Some aspects of risk management in construction industry, Strategie zarządzania ryzykiem w przedsiębiorstwie – formułowanie i implementacja strategii reakcji na ryzyko, red. J. Bizon-Górecka, Bydgoszcz (2000) 59-69, (in Polish).

6. O. Kapliński, Methods and models of research in building engineering, Wydawnictwo PAN KILiW IPPT, Warszawa, 2007 (in Polish).

7. O. Kapliński, Planning instruments in construction management, Technological and Economic Development of Economy 14 (4) (2008) 449-451.

8. D. Skorupka, The method of identification and quantification of construction project risk, Archives of Civil Engineering, LI (4) (2005) 647-662.

9. D. Kuchta, D. Skorupka, Project risk management taking into consideration the influence of various risk levels based on linguistic approach. World Scientific Proc. Series on Computer Engineering and Information Science 7; Uncertainty Modeling in Knowledge Engineering and Decision Making - Proceedings of the 10th International FLINS Conf 7, (2012) 1093-1098.

10. M. Połoński, K. Pruszyński, The time buffers location and critical chain concepts in civil engineering network schedule, Part I, Theoretical background, Przegląd Budowlany 2 (2008) 45–49 (in Polish).

11. M. Połoński, K. Pruszyński, The time buffers location and critical chain concepts in civil engineering network schedule, Part II, Practical application, Przegląd Budowlany 3 (2008) 55–62 (in Polish).

12. M.B. Woolf, Faster Construction Projects With CPM Scheduling, Mcgraw-hill Professional Publishing, 2007.

13. Goldratt E. M., Critical Chain, The North River Press, P.O. Box 567, 1997.

14. H. Steyn, An investigation into the fundamentals of critical chain project scheduling, International Journal of Project Management, 19 (2000) 363-369.

15. B. Flyvbjerg, M.S. Holm, S. Buhl, Underestimating Costs in Public Works, Error or Lie? American Planning Association Journal, 68 (3) (2002) 279-295.

16. B. Flyvbjerg, N. Bruzelius, W. Rothengatter, Megaprojects and Risk. An Anatomy of Ambition, Cambridge University Press, 2003.

17. J. Reilly, M. McBride, D. Sangrey D. MacDonald & J. Brown, The development of CEVP® - WSDOT’s Cost-Risk Estimating Process, Proceedings, Boston Society of Civil Engineers,, 2004.

18. M. Połoński, The analysis of the reliability of realization costs and investment’s time limits in Warsaw, Electronic Journal of Polish Agricultural Universities, Topic Civil Engineering 9 (4) (2006)

19. Guide to Building Construction Duration, Building Cost Information Service, London, 2004.

20. M. Połoński, Construction project budgeting including time buffers and costs, Proceedings of 60 konferencja naukowa Komitetu Inżynierii Lądowej i Wodnej PAN oraz Komitetu Nauki PZITB Krynica, 14-19 września 2014 r, (in Polish, in press).

21. R. Marcinkowski, Workbreakdown Structure (WBS) for bilding performance planning, Proceedings of Konferencji Naukowo-Technicznej Inżynieria Przedsięwzięć Budowlanych Wisła 2009, Katedra Procesów Budowlanych Politechnika Śląska, Gliwice (2009) 221-228 (in Polish).

22. D. Baccarini, Estimating project cost contingency - a model and exploration of research questions, in Khosrowshahi, Farzad (ed), ARCOM 20th Annual Conference, September, Heriot-Watt University, Edinburgh: Association of Researchers in Construction Management (2004) 105-113.

23. M. Połoński, A. Ziółkowska, Editing costs in MS Project, Archiwum Instytutu Inżynierii Lądowej, 13 (2012) 277-284 (in Polish).

24. M. Połoński, A. Ziółkowska, The effect of MS Project options on schedule update and EVM indicators calculation, Scientific Review Engineering and Environmental Sciences, 21 (3) (2012) 195-212 (in Polish).

25. K, Parzydło, Control of construction cost using Earned Value Method on the selected engineering object, (Master of Science dissertation), Warsaw University of Life Sciences, 2010 (in Polish).

26. F.K. Adams, Construction Contract Risk Management, A Study of Practices in the United Kingdom, Cost Engineering, 50 (1) (2008) 22-33.

27. K. Nassar, Cost Contingency Analysis for Construction Projects Using Spreadsheets, Cost Engineering, 44 (9) (2002) 26-31.

Archives of Civil Engineering

The Journal of Polish Academy of Sciences

Journal Information

SCImago Journal Rank (SJR): 0.251
Source Normalized Impact per Paper (SNIP): 0.521


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