The PBS(Product Breakdown Structure) is very important for the project management system.
It is this tree structure which must be first established when we want to structure a project. We ask “What must we do? ”, and we decline the perimeter of the project by equipments, materials, and civil works components. It is on this PBS that Activities (ABS) are deployed in order to carry out these Products. Then, these Products are possibly instantiated and then assigned to Zones (ZBS).
The Products are physical objects except for the design and tests phases, phases in which the PBS consists of functional system and subsystems (SBS).
When we wants to unify the costs and the time, and to define macroscopic workpackages to accommodate the tasks, it is necessary to be based on this Product tree structure. Indeed, it is necessary that the orders of equipments and materials, and their terms of payment, can be charged to the same element to ensure the coherence of system. It is thus understood that the workpackages must be Product oriented rather than by Activities and Zones.
The PBS is the framework of the schedule, that is why it is the first dimension of the 3D WBS.
