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PREPARED BY :
NOR AZAH BINTI AZIZ
KOLEJ MATRIKULASI TEKNIKAL KEDAH
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3.3 PROJECT NETWORK
DIAGRAM
OBJECTIVES
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Define Network DiagramPurpose of Network DiagramMethod : Activity On the Node (AON)Identify ES, EF, LS, LF using Forward Pass
Calculation and Backward Pass calculationIdentify Critical PathIdentify Slack Time
INTRODUCTION
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• A PND is a pictorial representation of the sequence in which the project work can be done.
• The activities and its duration are the basic building blocks needed to construct a graphic picture of the project
• Its provide - the earliest time at which work can be begin on every activity that makes up the project- the earliest expected completion date of the project
IMPORTANCE OF ND
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• ND can be used for ;i) Planning : gives a clear graphical picture of
the relationship between project activitiesii) Implementation : when updating the project
file with activity status and estimate to completion data, the ND is then automatically updated and can be printed or viewediii) control : while updated ND will retain the status of all activities, the best graphical report and controlling project work will be Gantt Chart
METHODS
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I) THE ACTIVITY ON THE NODE ( AON)
Basic unit of analysis in ND is the activity Each activity is represented by a
rectangle ( activity node) Arrows represent the
predecessor/successor relationship between activities
Every activity in the project will have its own activity node ( each rectangle)
METHODS
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I) THE ACTIVITY ON THE NODE ( AON)
A
B
C
D
E
F
PDM format of a project network diagram
METHODS
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I) THE ACTIVITY ON THE NODE ( AON)
Dependencies- A dependency is simply a relationship that
exists between pairs of activities- 4 types of activity dependencies
A B FS : A finishes, B start
METHODS
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I) THE ACTIVITY ON THE NODE ( AON)
Dependencies
FF : A finishes, B finishA
B
A
A SS : A start, B start
METHODS
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I) THE ACTIVITY ON THE NODE ( AON)
Dependencies
SF : A starts, B finish
A B
I) THE ACTIVITY ON THE NODE ( AON)
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I) THE ACTIVITY ON THE NODE ( AON)
Forward Pass calculations
Creating an initial project network schedule
A 1
B 3
C 2
D 5
E 2
F 3
Start End
EST, LST, EFT, LFT
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CPM uses the following times for an activity
EST - Early Start time is the earliest time the activity
can beginLST - Late Start Time is the latest time the activity
can begin- still allow the project to be completed on time
EFT - Early Finish Time is the latest time the activity can end
LFT - Late Finish Time is the latest time the activity can end
- still allow the project to be completed on time
Forward Pass calculations13
Backward Pass calculations14
CRITICAL PATH METHOD (CPM)
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An effective way to analyze complex projectsRepresent the critical set of activities to
complete a projectHelp to focus on essential activities which are
critical to run the projectAllows the project manager to concentrate on
important activitiesCP is the longest path on ND and the most
important partAny delays on the CP will lead to delay of the
project
CRITICAL PATH METHOD (CPM)
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FLOAT
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• Also known as slack, total float and path float• Is computed for each task by subtracting EFT
from the LFT( @ the early start from the late start)
• Is the amount of time the task can slip without delaying the project finish date.
• Free float is the amount of time a task can slip without delaying the early start of any taskthat immediately follows it.
Slack Time calculations18
EXAMPLE
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Activity Precursor Duration (week)
A - 7
B A 6
C A 5
D A,B 4
E B,C 3
F D,E 2
1. TABLE 1 shows the activities and the durations required to complete a construction project, including the precursor activity.
Refering to the TABLE 1:i) draw the project network diagram.
ii) state the activities on the critical path.iii) calculate the minimum duration of the project.
20 project network diagram
A
D
C
E
FBSTART END
0 7 7
0 0 7
13 4 17
13 0 17
7 6 13
7 0 13
7 5 12
9 2 14
14 3 16
14 1 17
17 2 19
17 0 19
19 19
19 19
0 0
0 0
activity
ES D EF
LS F LF
