Probabilistic Scheduling for Repetitive Projects

Photios G. Ioannou1 & Chachrist Srisuwanrat2

1Professor, Civil and Environmental Engineering Department, Univ. of Michigan, MI 48109-2125, Phone +1 734/764-3369, FAX +1 734/764-4292, [email protected]
2Doctoral Candidate, Civil and Env. Engineering. Department, Univ. of Michigan, MI 48109-2125, Phone +1 734/764-3369, FAX +1 734/764-4292, [email protected]


The sequence step algorithm for probabilistic scheduling of repetitive projects is a generalized methodology for scheduling projects with activities that repeat from unit to unit and have probabilistic durations. In simple terms it can be compared to PERT but for resource-constrained scheduling. The sequence step algorithm addresses for the first time the problem of scheduling repetitive projects with probabilistic activity durations while keeping resources (crews) employed continuously. This algorithm can be implemented in most general-purpose simulation systems. The algorithm is presented in detail and is applied to an example project with 7 activities and 4 repetitive units using a simulation model developed in Stroboscope, an activity-based simulation system. Numerical and graphical results help explain the algorithm and provide insight into the underlying tradeoff problem between reducing the expected crew idle time and increasing the expected project duration.


Scheduling, repetitive projects, linear projects, line of balance, probabilistic scheduling, resource continuous constraints, uninterrupted work flow, simulation.



Ioannou, P. G. & Srisuwanrat, C. 2007. Probabilistic Scheduling for Repetitive Projects, 15th Annual Conference of the International Group for Lean Construction , 498-507.

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