Critical Path Method (CPM) is the standard scheduling methodology for building construction in the US. The objective of this research is to determine the effect of management strategies focusing on early starts (ASAP strategy) on the production and productivity rates of “critical path” tasks in a construction schedule. In this study, two healthcare projects were followed over the course of construction to document the effects of field management decisions on production. On project one, a CPM schedule and ASAP strategy was used exclusively to manage subcontractor resources. On project two, both CPM/ASAP and Location Based Management System (LBMS) strategies were used in parallel, on similar location groups, enabling direct comparison. Actual activity start dates, finish dates, demobilizations and remobilizations, productivity and production rates, and manpower were recorded weekly for analysis. On project one, the actual dates and rates are compared against the CPM plan to determine how reliably the tasks could be completed using the ASAP “work in place” management strategy. Results show that certain deviations from the CPM plan, such as starting early, relocating resources before completing a location, and deploying resources to multiple locations at a time cause unpredictable dates of completion and frequent changes to the “critical path”. On project two, actual productivity and production rates for selected tasks are compared between the CPM/ASAP and LBMS location groups. Results show that deploying resources to a location as soon as it is available can have a negative effect on the productivity and overall production rates of critical tasks
Continuous, CPM, flow, LBMS, process, production, variability.
Evinger, J. , Mouflard, C. & Seppänen, O. 2013, 'Productivity Effects of Starting as Early as Possible in Hospital Construction' In:, Formoso, C. T. & Tzortzopoulos, P., 21th Annual Conference of the International Group for Lean Construction. Fortaleza, Brazil, 31-2 Aug 2013. pp 689-698