Scheduling as Part of the Project Management Effort - Construction Project Scheduling and Control - page 285

government agencies, vendors, and so forth. There are two approaches to scheduling
in this situation:
1. Build a master schedule that includes several subschedules : Each subschedule
represents the activities belonging to one party involved in the project. The
external relationships will show only in the master schedule. In this approach,
when scheduling (performing the CPM calculations for) a subschedule, the
scheduler must be sure to consider the external relationships because the soft-
ware may ignore them. For instance, consider the three activities shown in
Figure 10.4. Assume the relationship between activity GC230 and activity
SDF1270 is external. If you schedule the SDF schedule alone, you may get
early dates for activity SDF1270 as (35, 40) instead of (51, 56).
This solution was ideal under the old Primavera P3, where the user could not
open more than one project at a time but could open one master schedule with sev-
eral subschedules under it. In the enterprise version of Oracle Primavera P6, the user
can open as many projects as he or she wants, simultaneously. The user in P6 also
can link activities in different projects with the option to consider or ignore external
relationships when scheduling. The user in P6 can also take advantage of the EBS
(enterprise breakdown structure) by placing the subschedules at one level below the
master schedule.
2. Include all activities in one schedule and assign a responsibility code for each con-
tracting party : The scheduler can later apply a filter to show activities belonging
to only one party. In this way, the “external relationships” are always there,
even if they are not shown.
It is important to include external relationships for proper project management.
For example, an owner's furnished kitchen equipment for a commercial project may
have to be delivered after the structure has been erected and after mechanical and elec-
trical rough-ins are completed, but before doors and windows are installed and before
Figure 10.4 Subnet of a master schedule with two activities belonging to one subschedule
and one activity belonging to a different subschedule