Schedule Compression and Time-Cost Trade-Off - Construction Project Scheduling and Control - page 245

13. You are the scheduler for a large commercial building project. The schedule that
you prepared (based on feedback from the project manager) falls 15 days short
of the owner's deadline. The project manager decides to write a memo to all of
the subcontractors, requiring them to work 6 days per week, 10 hours per day.
You ask the project manager to wait until you determine the most efficient way
to crash the project. Outline your argument to convince the project manager to
go with a certain accelerating plan that focuses on the critical path and not all
activities.
14. In general, what is the effect of accelerating an activity on the direct costs of a
project? Why?
15. What is the effect of accelerating an activity on the indirect costs of a project?
Why?
16. In general, what happens to the total cost of a project when you start accelerating
and keep accelerating the scheduleuntil you reach the least possible duration?
17. Explain your answer to the previous question graphically. Make sure you show
the points of normal duration (ND), normal cost (NC), least cost (LC), least-cost
duration (LCD), crash duration (CD), and crash cost (CC).
18. Visit a construction site and meet with the project manager. Ask the project man-
ager what it would take to reduce the project's duration by 5 days. Try to quantify
the extra cost and benefits for such an acceleration. Ask the project manager about
the means he or she would use to achieve such an acceleration.
19. What is a recovery schedule ?
20. Calculate the normal, least-cost, and crash durations for the following project.
Calculate the cost associated with each duration. Indirect (overhead) costs are
$100 per day.

Duration (days) Cost ($)

Activity IPA Normal Crash Normal Crash

A - 7 5 500 640

B A 6 5 550 630

C A 8 5 800 935

D B 10 7 1,200 1,440

E B, C 6 4 600 700

F C 4 3 500 590

G D, F 4 2 700 1,000

H E, F 7 4 650 950

I G, H 2 2 300 300

21. Calculate the normal, least-cost, and crash durations for the following project.
Calculate the cost associated with each duration. Indirect (overhead) costs are
$120 per day.