1. CPM Network Computation
Spring 2008, King Saud University
Activity on Node
Dr. Khalid Al-Gahtani

2. AOA AON Spring 2008, King Saud University Activity on Node
Dr. Khalid Al-Gahtani

3. Drawing CPM Networks
Prerequisites: Before drawing a CPM network, we must have:
List of all activities comprising the project
Order of precedence of each activity
Duration estimate of each activity
Spring 2008, King Saud University
Activity on Node
Dr. Khalid Al-Gahtani

4. Example: Spring 2008, King Saud University Activity on Node
Dr. Khalid Al-Gahtani

5. Activity on arrow Solution
Spring 2008, King Saud University
Activity on Node
Dr. Khalid Al-Gahtani

6. Activity-on-node Solution
Spring 2008, King Saud University
Activity on Node
Dr. Khalid Al-Gahtani

7. Spring 2008, King Saud University
Activity on Node
Dr. Khalid Al-Gahtani

8. “Activity on Node” Nodes = Activities Links = Precedence Relationships
Dummy activities are not required
Spring 2008, King Saud University
Activity on Node
Dr. Khalid Al-Gahtani

9. Example Spring 2008, King Saud University Activity on Node
Dr. Khalid Al-Gahtani

10. AON Spring 2008, King Saud University Activity on Node
Dr. Khalid Al-Gahtani

11. AON Spring 2008, King Saud University Activity on Node
Dr. Khalid Al-Gahtani

12. Constraints with Lead/lag time
Spring 2008, King Saud University
Activity on Node
Dr. Khalid Al-Gahtani

13. Finish-to-Start (FSij):
FSij is equal to the minimum number of time units that must transpire from the completion of the predecessor (i) prior to the start of the successor (j).
The time between the finish of one activity and the start of its successor is called “Lag”.
Spring 2008, King Saud University
Activity on Node
Dr. Khalid Al-Gahtani

14. Finish-to-Start (FSij):
If the relationship is not listed on the dependency arrow, FS is assumed with Lag= 0.
Example: a planner may wish to have an activity of removing formwork from a new building component follow the concrete pour by some pre-defined lag period to allow setting.
Spring 2008, King Saud University
Activity on Node
Dr. Khalid Al-Gahtani

15. Start-to-Start (SSij):
SSij is equal to the minimum number of time units that must be complete on the preceding activity (i) prior to the start of the successor (j).
Spring 2008, King Saud University
Activity on Node
Dr. Khalid Al-Gahtani

16. Start-to-Start (SSij):
“Lag” is always applied to SS relation.
Example: parallel in starting of Installing and Finishing the walls activity of 100 rooms on a project must be 10 days difference (SS=10 days).
You don’t have to wait installing 100 wall’s room to start doing the finishing work.
Spring 2008, King Saud University
Activity on Node
Dr. Khalid Al-Gahtani

17. Finish-to-Finish (FFij):
FFij is equal to the minimum number of time units that must remain to be completed on the successor (j) after the completion of the predecessor (i).
It is applied as productivity control.
Spring 2008, King Saud University
Activity on Node
Dr. Khalid Al-Gahtani

18. Finish-to-Finish (FFij):
The finish date of Installing and Finishing walls’ activity of 100 rooms on a project must have 10 days difference in order to control productivity (FF=10 days).
In this example, the productivity of installing the walls’ activity might be less than finishing the rooms’ activity.
“Lag” is always applied to FF relation as buffer between the two activities.
Spring 2008, King Saud University
Activity on Node
Dr. Khalid Al-Gahtani

19. Start-to-Finish (SFij):
SFij is equal to the minimum number of time units that must transpire from the start of the predecessor (i) to the completion of the successor (j).
It is applied also for controlling productivity
Spring 2008, King Saud University
Activity on Node
Dr. Khalid Al-Gahtani

20. Start-to-Finish (SFij):
Example: The start date of Installing 100 rooms’ wall’s activity and the finish date of Finishing same walls’ activity of a project must maintain 30 days difference to control productivity (SF=30 days).
“Lag” is always applied to SF relation as buffer between the two activities.
It is not recommended to use by planner.
Spring 2008, King Saud University
Activity on Node
Dr. Khalid Al-Gahtani

21. Start-to-Start and Finish-to-Finish (ZZij):
ZZij is a combination of two constraints. i.e., a start-to-start and finish-to-finish relationship. It is written with the SSij time units first, followed by the FFij time units.
These two relations are used combined to maintain buffer between the start and finish of two activities.
Spring 2008, King Saud University
Activity on Node
Dr. Khalid Al-Gahtani

22. Forward Pass Computations
EFj = ESj + Dj
Spring 2008, King Saud University
Activity on Node
Dr. Khalid Al-Gahtani

23. Backward Pass Computation
LSi = LFi  Dj
Spring 2008, King Saud University
Activity on Node
Dr. Khalid Al-Gahtani

24. Example Spring 2008, King Saud University Activity on Node
Dr. Khalid Al-Gahtani

25. Example Solution Spring 2008, King Saud University Activity on Node
Dr. Khalid Al-Gahtani