Schedule Compression and Time-Cost Trade-Off - Construction Project Scheduling and Control - page 235

We compress each of these activities by 1 day to shorten the project duration
from 22 days to 21 days.

Cycle 4
Path Duration (days)

ABEH 24 24 23 22 21

ACEH 25 24 23 22 20

ACFH 23 22 22 21 20

ACFG 24 23 23 22 21

ADG 23 23 23 22 21

Note that path ACEH was cut by 2 days because it contains both C and E.
Now the total cost has increased by $20 ($140 increase in direct costs and
$120 decrease in indirect costs). The next step is to find an alternative to
activity E because it is completely crashed. The next least-cost combination is
B, C, and D, at a total cost of $165. In this case, the total cost has increased
by $45.

Cycle 5
Path

Duration (days)

ABEH 24 24 23 22 21 20

ACEH 25 24 23 22 20 19

ACFH 23 22 22 21 20 19

ACFG 24 23 23 22 21 20

ADG 23 23 23 22 21 20

Note that the critical paths may change in every round. Now, activity C is
also completely crashed. Our next choice is the combination of B and G at a
combined cost of $225, with a net increase of $105 in the total cost.

Cycle 6
Path Duration (days)

ABEH 24 24 23 22 21 20 19

ACEH 25 24 23 22 20 19 19

ACFH 23 22 22 21 20 19 19

ACFG 24 23 23 22 21 20 19

ADG 23 23 23 22 21 20 19

Activity B is now completely crashed. All paths are tied at 19 days. The
only remaining option is to combine activities G and H at a cost of $270, with
an increase of $150 in the total cost.