# CPM Network Computation

## Presentation on theme: "CPM Network Computation"— Presentation transcript:

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

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

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

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

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

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

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

“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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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