New approach to improve general contractor crew's work continuity in repetitive construction projects

A significant number of construction projects involve repetitive processes. Planning them occurs to be a complex task. Network methods traditionally applied to construction scheduling prove inefficient in the case of repetitive construction projects (RCPs) due to the increased number of relationships among processes, locations (units), and resources. Frequently, the aim of scheduling RCPs is making the full use of the resources' capacity, thereby ensuring continuity of the crews' work. To achieve this, the planner typically allows discontinuity of some secondary processes to shift resources to the key processes, allowing optional modes of process delivery and introducing soft precedence relations between processes. This paper presents a new way of increasing the continuity of work of a general contractor's crews in RCPs by employing subcontractors' crews. A deterministic mathematical model of the mixed-integer linear problem of a repetitive (nonlinear) project was formulated to find a schedule that minimizes the downtime of the general contractor's crews under constraints of a maximum acceptable total project duration and a maximum acceptable cost of the works commissioned to subcontractors; the model accounts for the limited availability of crews. Application of the model is illustrated by an example.