Planning and scheduling drainage infrastructure maintenance operations under hard and soft constraints: a simulation study

The problem of planning drainage services in a certain timeframe by a typical municipal infrastructure maintenance organization lends itself well to existing solutions for resource constrained project scheduling optimization. However, the optimized schedule could be deemed insufficient from a practitioner's perspective as the very crucial soft constraint on the competence of a particular crew handling different jobs is excluded. We define a crew-job matching index ranging from 0 to 1 to allow for a planner's assessment to be factored in job schedule simulation and optimization. The total crew-job matching index (TCJMI) is further defined, accounting for all the crew-job assignments and indicating the fitness of a formulated plan. TCJMI is maximized in the resource-constrained schedule optimization by applying Excel Solver add-in. As such, the planner's preference and experience can be represented and factored in crew-job scheduling optimization, which is demonstrated through conducting "what-if" simulation scenario analyses.