Flexible Activity Relations to Support Optimum Schedule Acceleration: Fid-Bau Portal

Flexible Activity Relations to Support Optimum Schedule Acceleration

Abuwarda, Zinab / Hegazy, Tarek

In construction schedules, a logical relationship between two activities is specified by the relationship type and a fixed lag time. This rigid representation, however, does not consider the situation when two activities have a degree of flexibility in their relationship. Such flexibility, or soft relation, can be very beneficial as it provides a range of overlapping options that can be utilized in situations that require the schedule to be optimally accelerated. This paper thus proposes a formalization of a generic logical relationship (hard or soft) of any type (finish-to-start, etc.) between any two activities. Using the generic representation, modified activity start and finish time computations are presented to accommodate the overlaps associated with soft relations, and are used in a schedule-crashing model. The model determines the optimum combination of activity crashing and overlapping decisions that minimizes project cost without violating the resource constraints. The new activity relationship and crashing model are beneficial to both researchers and practitioners as they facilitate schedule optimization decisions for projects that exercise a good level of overlapping, such as fast-track projects.