Post on 02-Feb-2016
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PROJECT NETWORK DIAGRAM
PREPARED BY : NOR AZAH BINTI AZIZ
KOLEJ MATRIKULASI TEKNIKAL KEDAH
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OBJECTIVES
• Define Network Diagram• Purpose of Network Diagram• Method : Activity On the Node (AON)• Identify ES, EF, LS, LF using Forward Pass
Calculation and Backward Pass calculation• Identify Critical Path• Identify Slack Time
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INTRODUCTION
• 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
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IMPORTANCE OF ND
• 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
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METHODS
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)
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METHODS
I) THE ACTIVITY ON THE NODE ( AON)
A
B
C
D
E
F
PDM format of a project network diagram6
METHODS
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
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METHODS
I) THE ACTIVITY ON THE NODE ( AON)
Dependencies
FF : A finishes, B finishA
B
A
A SS : A start, B start8
METHODS
I) THE ACTIVITY ON THE NODE ( AON)
Dependencies
SF : A starts, B finish
A B
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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
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EST, LST, EFT, LFT• CPM uses the following times for an activity
EST - Early Start time is the earliest time the activity can begin
LST - 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 endLFT - Late Finish Time is the latest time the activity can end
- still allow the project to be completed on time
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Forward Pass calculations 13
Backward Pass calculations 14
CRITICAL PATH METHOD (CPM)
• An effective way to analyze complex projects• Represent the critical set of activities to complete a project• Help to focus on essential activities which are critical to run
the project• Allows the project manager to concentrate on important
activities• CP is the longest path on ND and the most important part• Any delays on the CP will lead to delay of the project
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CRITICAL PATH METHOD (CPM)
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FLOAT
• 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.
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Slack Time calculations 18
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.
20project 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