Precedence Networks - Construction Project Scheduling and Control - page 113

Solution with Contiguous Activities

Activity ES EF LS LF TF FF

A 0 10 0 10 0 0

B 0 12 2 14 2 0

C 3 7 3 7 0 0

D 2 30 2 30 0 0

E 24 38 24 38 0 0

F 12 22 14 24 2 2

G 24 44 24 44 0 0

H 30 39 35 44 5 5

I 44 56 44 56 0 0

The simple difference between the two solutions is that in the case of
contiguous activities, we do not allow restricted float. Once an activity starts,
it must continue till it is finished. Calculations were going similar until activ-
ity E. The early dates (24, 38) were calculated from its FF relationship with
activity D. This is not good enough for activity G, whose critical start on the
22nd day depends on the start of activity E. This forces a delay in activity
G, which will delay the entire project by 2 days. As a result, the critical path
becomes: A, C, D, E, G. This leaves only three noncritical activities: B, H, and
F. Activities B and F were critical in the “interruptible activities” solution but
now gained a float of 2 days as a result of forcing this 2-day delay on activity G.

Figure 5.26 Network for example 5.2