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(PS-3856) Applying Multiple Calendars in a Projects Schedule – Peace of Mind, or Source of Concern?

Level: Intermediate
TCM Section(s):
7.2. Schedule Planning and Development
7.4. Resource Planning
Venue: 2022 AACE International Conference & Expo

Abstract: Calendars and the accurate utilization of them is one of the most important subjects to the success of a project schedule. Due to the variety of environmental and non-environmental restrictions in most of the large-scale and complex construction projects (i.e., in-water work restrictions, road or track closures, winter shutdown, resource availability, night shift work), defining and applying multiple calendars with different allowable working days and working hours representing these restrictions is a necessity.

Although schedules using multiple calendars is a generally accepted practice (even required in some cases), different calendars do not always work well together and in some cases provide dilemmas. While multiple calendars may offer peace of mind, in some cases can negatively impact the project schedule indexes and become a source of concern.

Some of the negative impacts and effects of utilizing multiple calendars in the project schedules are discussed using several real case study projects. Approaches for preventing or mitigating such negative impacts and effects are also presented.