This paper was first published in the Canadian Journal of Civil Engineering, Vol. 21, 1994 pp 939-953, under the title "A Pragmatic Approach to Using Resource Loading, Production and Learning Curves on Construction Projects". It has been modified only to the extent necessary to make it presentable in web page format.

Published here October, 2001.

Abstract | Introduction | Resource Loading | S-curves | What can be Learned?
Productivity Improvement | Learning vs. Experience | Original Theory | Two Approaches
Illustration | Issues | Conclusions | References | Appendix 1 | Appendix 2 

Issues Regarding Total Time and Stage 1 Time

A reasonable question to ask is how can the planner be assured of choosing the right overall time (i.e., equivalent to 100%) and why should the learning always take 30-35% of that value? Should it not be possible to contemplate a 36-storey high-rise, rather than 24, and still achieve the Stage 2 efficiency of the 24 storey high-rise in the first six floors?

The practical reality is that if the building is that much larger in all likelihood the whole scale of the project operation is correspondingly larger and will be planned and organized accordingly. This includes increased use of temporary materials, plant, equipment and site organization all optimized to suit the larger project.

The planned time must also be realistic and achievable, especially if it is being compressed. Having chosen this time, it is essential that all the supporting logistics of the site, including management, supervision, equipment, supplies etc., are all present to support this choice. Failing this, it is the authorÍs observation that the job then "takes on a will of its own" wherein it charts its own progress record. Thus, it is the organizational culture associated with the site that ultimately determines the final outcome.

As one example of what can go wrong, Figure 15 compares actual production of rock excavation with planned production on a less than well managed site preparation contract.[6] Partly due to changes, final quantities were significantly higher than originally anticipated, the planned peak level of production was never reached, and Stage 1 of the S-curve took more time. Not surprisingly in this case, the whole contract took a lot longer to complete — and ended in litigation.

Figure 15 - Comparison of actual vs. planned production of bulk rock excavation
Figure 15: Comparison of actual vs. planned production of bulk rock excavation.
Percent cumulative total is based on original estimate of 133 000 m3 (174,000 cubic yards)
Illustration of Learning Curve Application  Illustration of Learning Curve Application

6. From the authorÍs personal records of an actual contract.
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