Sachpazis Costas: Geotechnical Engineering: A student's Perspective Introduction
Easy steps to critical path determination and floats calculations for projects
1. Easy Steps to Critical Path
Determination and Floats Calculations
for Projects
Project Management
Dr. Mahmoud Abbas Mahmoud
Asst. Prof.
2016
2. Easy Steps to Critical Path
Determination and Floats Calculations
for Projects
We will illustrate these
steps with the following
Example:
Dr. Mahmoud Abbas Mahmoud
3. A= 10
B= 7
1
2
3
C= 5
D= 6
E= 9
4
5
6Dummy
F= 8
Dr. Mahmoud Abbas Mahmoud
G= 12
0
Example:
For the project given in the following (AOA) network diagram:
i) Find the critical activities.
ii) Find the critical path (CP).
iii) Find project completion time.
iv) Find the free float (FF) for each activity.
v) Summarize the results in a table.
Note: all times are in (weeks)
27. A= 10
B= 7
1
2
3
C= 5
D= 6
E= 9
4
5
6Dummy
F= 8
Dr. Mahmoud Abbas Mahmoud
G= 12
0
0
0
10
10
15
15
24
16
24
24
36
36
How to find the Critical Activities and
the Critical Path ???
28. Dr. Mahmoud Abbas Mahmoud
Remember that only a critical
activity can have a Zero Total
Float (TF)
29. Dr. Mahmoud Abbas Mahmoud
Therefore, we will calculate
the total floats for all
activities and each activity
has a ZERO total float (TF) will
be a critical activity.
60. Dr. Mahmoud Abbas Mahmoud
Free FloatActivity
0A
8B
0C
0D
0E
12F
0G
8Dummy
Think !!!!
61. Dr. Mahmoud Abbas Mahmoud
We can notice from these
results that all critical activities
must have zero free floats but
not each activity that has zero
free float must be critical.
For example, activity (D) has
zero Free Float but it is not
critical.
Free FloatActivity
0A
8B
0C
0D
0E
12F
0G
8Dummy
62. Summary
Activity
Symbol
Activity
(i, j)
Duration
Dij
ESi LCj TFij FFij
A (1, 2) 10 0 10 0* 0
B (1, 3) 7 0 15 8 8
C (2, 3) 5 10 15 0* 0
D (2, 4) 6 10 24 8 0
E (3, 5) 9 15 24 0* 0
Dummy (4, 5) 0 16 24 8 8
F (4, 6) 8 16 36 12 12
G (5, 6) 12 24 36 0* 0
Notice that total float (TF) values marked with (*) mark
are for critical activities.
Dr. Mahmoud Abbas Mahmoud