1. Exercise 1
1.What are the different factors that can
cause project delays in the construction?
How to prevent these delays in order to
finish the project on time? Discuss the
possible consequences if the project will
be delayed.
3. At the end of this lesson, students will be able to;
1. Learn the principles of PERT/CPM;
2. Construct PERT/CPM Network Diagram;
3. Identify the Critical Path and Critical Duration/Activities;
4. Determine the Early start, Early finish, latest start, latest finish, and
Slack/Float time.
Learning Outcomes
4. Project – It is an interrelated set of activities that has a definite starting and
ending point and that results in a unique product or service.
Project Management - It is scientific way of planning, implementing,
monitoring and controlling the various aspects of a project such as time,
money, materials, manpower and other resources.
GOAL: To complete the project on time without possible delays.
5.
6. PERT (Project Evaluation and Review Technique)
• It is a method that analyzes the time required to complete each
task and to determine the minimum amount of time required to
complete a certain project. Thus, delays can be prevented (Arun,
2023).
• It is a graphical representation of a project's timeline that displays
all of the individual tasks necessary to complete the project (Kopp,
2022).
What is PERT?
7. CPM (Critical Path Management)
• It is a method used in preparing, organizing, coordinating, and controlling
in projects.
• The longest path in the network diagram is the critical path and its
activities are called critical activities.
• If there are delays in the longest or critical path, naturally there is also a
corresponding delay in project completion time (Fajardo, 2000).
• However, shorter path may experience some delays but may not affect the
overall project completion time (Asahid et.al, 2015)
What is CPM?
8. Under PD 1594, The program, of works shall include among
other things, estimates of the work items, quantities, costs
and a PERT/CPM network diagram showing the project
activities . . . In the preparation of the bidding documents, the
government shall make and estimate the project through
PERT/CPM analysis of the project activities and corrected for
holidays and weekends.
What is CPM?
13. Advantages:
1. PERT/CPM helps in planning for big projects
2. Finish the project on time
3. Identify the Critical path
4. Analysis of each activity in PERT/CPM
5. Coordination/Collaboration within the team
6. The What – if Analysis
Advantages and Disadvantages of PERT/CPM
14. Disadvantages:
1. Time – focused method – creates pressure in the team
2. Inaccurate prediction of time duration
3. Expensive in terms of time consumed, research,
prediction, and resources utilized.
4. Requires knowledge about PERT/CPM
Advantages and Disadvantages of PERT/CPM
15. • A project manager/engineer creates a PERT chart in order
to analyze all the project's tasks while estimating the
amount of time required to complete each one.
• Using this information, the project manager/engineer can
estimate the minimum amount of time required to
complete the entire project.
• This information also helps the manager develop a project
budget and determine the resources needed to accomplish
the project.
How does PERT/CPM works?
16. • A PERT/CPM is a visual representation of a series of
activities that must occur within the scope of a project’s
lifetime.
• The direction of arrows indicates the flow and sequence
of events required.
• Dotted activity lines represent dummy activity.
• Numbers and time allotments are assigned and shown
inside each vector.
How is a PERT/CPM interpreted?
17. 1. PLANNING PHASE
2. SCHEDULING PHASE
3. CONTROL AND MONITORING PHASE
Three Phases of PERT/CPM
19. Planning:
Five Inputs in Planning Phase:
1. A network diagram defining the activities in the project.
2. The duration of activities.
3. Cost estimates
Three Phases of PERT/CPM
20. Scheduling:
Scheduling is defined as the process of translating
the arrow diagram into timetable of calendar
days. Based on the time estimates, the start and
finish times for each activity are worked out by
applying an arrow diagram. Then, critical path is
identified.
Three Phases of PERT/CPM
21. Four Output in Scheduling Phase:
1. The schedule of activities in the network showing the following:
a. The critical activities.
b. The Earliest start date for each activity.
c. The Earliest finish date for each activity
d. The Latest Start date for each activity.
e. The Latest Finish date for each activity.
f. The Float which refers to the amount of extra time available for an activity.
2. Bar Chart, Gantt Chart, or a Time Scaled Network (Arrow diagram, network for
the project)
Three Phases of PERT/CPM
22. Three Phases of PERT/CPM
Controlling/Monitoring:
It refers to analyzing and evaluating the actual progress based on
the plan. There is a need to review of project activities subjected to
changes as to duration, description, and cost estimates.
23. The Control Monitor Phase uses actual data which includes:
1. Addition of activities to the project – refers to new activities.
2. Deletion of activities from the project.
3. Changes as to duration, description, trade indicators, cost estimates
or resources estimates,
4. Actual starting dates.
5. Actual finishing dates.
Three Phases of PERT/CPM
25. Fundamental Elements of PERT/CPM Network Diagram
1. Activity – It is the work operation required to complete the project and is represented by an
arrows.
2. Event – It is a point in time signifying the beginning and end of one or more activities. It is
indicated on the network as a circle, square, or maybe other geometrical shapes.
26. Fundamental Elements of PERT/CPM Network Diagram
3. Dummy – It does not consume time and may be used in the network diagram to distinguish two or
more parallel activities.
4. Merge and Burst Event – One or more activities can start and end simultaneously at an event.
27. 5. Preceding and Succeeding Activities – Activities A and B precede C and D
respectively. Activity C and D are the succeeding activities.
Fundamental Elements of PERT/CPM Network Diagram
6. Duration of Activity – It is the time (weeks or days) it takes an activity to be
finished or the expected/assigned duration of each task/activity. It also refers to
Early Start (ES) to its Early Finish (EF) or from Latest Start (LS) to its Late Finish
(LF).
28. 7. Path – It is a sequence of activities that leads from the starting node to the
finishing node to the finishing node. Example: Path A –C – F, Path B-D-E-F
Fundamental Elements of PERT/CPM Network Diagram
32. Errors to be Avoided in PERT/CPM Network Diagram
33. Errors to be Avoided in PERT/CPM Network Diagram
34. Angelo: For me, PERT/CPM is so very owki! No sweat! Char!
Haryl: PERT/CPM was developed independently in the later part of 1950’s.
Tom Andrei: Do you want examples in PERT/CPM?
38. Example 1: Assuming that you are doing a certain project and your
proposed sequence of activity is shown below. Construct the
PERT/CPM Network Diagram.
Activities Precedence Duration
A -------- 2 days
B A 1 day
C (end) B 3 days
39. Example 2: Assuming that you are doing a certain project and your
proposed sequence of activity is shown below. Construct the
PERT/CPM Network Diagram.
Activities Precedence Duration
A -------- 2 days
B -------- 2 days
C (end) A and B 3.5 days
40. Example 3: Assuming that you're doing a certain project and your
proposed sequence of activity is shown below. Construct the
PERT/CPM Network Diagram.
Activities Precedence Duration
A -------- 2 days
B A 1 day
C A 2 days
D B 3 days
E C 4 days
F (end) D and E (end) 3 days
41. Example 4: Assuming that you're doing a certain project and your proposed
methodological flowchart is shown below. Construct the PERT/CPM Network
Diagram.
Activities Precedence Duration
A -------- 2 days
B -------- 1 day
C A 2 days
D (end) B 2 days
42. Example 5: Assuming that you are doing a certain project and your proposed
methodological flowchart is shown below. Construct the PERT/CPM Network
Diagram.
Activities Precedence Duration
A -------- 2 days
B -------- 1 day
C A, B (end) 1 day
D (end) A, B (end) 1 day
43. Example 6: Assuming that you are doing a certain project and your proposed
sequence of activity is shown below. Construct the PERT/CPM Network Diagram.
Activities Precedence Duration
A -------- 2 days
B -------- 1 day
C (end) A 1 day
44. Example 7: Assuming that you're doing a certain project and your proposed
sequence of activity is shown below. Construct the PERT/CPM Network Diagram.
Activities Precedence Duration
A -------- 3 days
B A 2 days
C A 3 days
D B 3 days
E C 2 days
F D 3 days
G (end) E 4 days
H (end) F 2.5 days
45. Example 8: (a) Construct the PERT/CPM Network Diagram, (b) determine the
critical path, and (c ) determine the critical duration for a house construction
project. The sequence of the activities with their predecessors are given below.
46. Example 9: Sequence of Activities for Building Construction Project is shown
below. Construct the PERT/CPM Network Diagram.
58. Example 10: Sequence of Activities for Building Construction Project is shown
below. Construct the PERT/CPM Network Diagram.
Estimated
Time
(days)
3 3 2 2 2.5 3.5 4 4.5 5 5 3
59. Example 11: Sequence of Activities for Building Construction Project is
shown below. Construct the PERT/CPM Network Diagram and identify the
critical path.
Estimated
Time
(days)
3 3 2 2 2.5 3.5 4 4.5 5 5 3 3
60. 1. The length or time of any path can be determined by adding the
expected time of the activities along the path.
2. The path with the longest time is the critical path and possible delays
must be avoided because the whole duration will be affected.
3. The expected duration of a project is equal to the expected time of the
longest path.
4. The longest path is the critical path, and its activities are called the
critical activities and duration.
5. Short path may experience some delay, but it won’t affect the overall
project completion time as long as the longest path does not exceed the
length of the critical path.
PERT/CPM
61. 6. If the project is to be completed in that shortest time, all activities on the critical path
must be started as soon as possible.
7. If the project has to be completed ahead of the schedule, then the time required for
at least one of the critical activity must be reduced.
8. Any delay in completing the critical activities will increase the project duration.
9. The activity, which does not lie on the critical path is called non – critical activity.
10. Slack or Float is the amount of time by which the start of an activity may be delayed
without affecting the overall completion time of the project.
11. But a critical activity that lies in a critical path has no slack or float.
12. To reduce the overall project time, it would require more resources (5 M’s) to lessen
the time taken by the critical activities to complete.
PERT/CPM
62. ES (Early Start) – The early start of time activity. It is assumed that all
preceding activities start at the earliest time.
ES = ES + Duration
EF (Early Finish) – Early Finish of time activity.
LS (Latest Start) – Latest time the activity can start and not delay the project.
LF (Latest Finish) – Latest time the activity can Finish and not delay the
project.
PERT/CPM
“Scheduling of Activities”
63. PERT/CPM
“Scheduling of Activities”
Forward Pass Computations to calculate the ES and EF
1. The Earliest Finish (EF) for any activity is equal to its earliest starting time plus its expected
duration time.
EF = ES + Time Duration
2. For nodes with one entering arrow, Early Start for activities at such node is equal to Early Finish.
3. For nodes with multiple entering arrows, the Early Start for activities leaving such node is equal
to the largest Early Finish (EF).
64. PERT/CPM
“Scheduling of Activities”
Backward Pass Computations to calculate the LS and LF
1. Begin from end node/event and move towards the start event/node. Assume that the direction
of arrows is reversed.
2. The Latest Finish (LF) of the last node is equal to its Early Finish (EF).
3. The preceding Latest Start is equal to Latest Finish minus Duration
4. If there are more than one incoming activities, take the minimum value of Latest Start.
65. PERT/CPM
“Scheduling of Activities”
Determination for Slack or Float Time
1. The critical activities don’t have slack/float time, or it is equal to zero BUT Non
– critical activities may have some.
2. The float or slack of an activity is the amount of the time available by which it is
possible to delay its completion time without extending the overall project
completion time.
Formula:
Float/Slack = Latest Start (LS) – Early Start (ES)
66. Consider the sequence of activity as shown below for the construction of small bungalow residential
house with a floor area of 42 sq.m.
Example 1
Activity Precedence Event Description Duration
A ------- 1-3 Purchase and delivery of
Materials, and Securing of
permits/clerances
3 days
B ------- 2-3 Layouting and Excavation 5 days
C A, B 3-4 Footing/Foundation 4 days
D C 4-5 Columns 6 days
E C 4-6 Tie Beams 3 days
F D 5-6 Amakan walling and Roofing
works
5 days
G E, F (end) 6-7 Finishes 6 days
67. A project schedule has the following characteristics as shown below.
Example 2
68. Consider the project scheduling as shown below:
Example 3
Activity Node/Event Description Duration (days)
A 1-2 Demolition and Clearing 8
B 2-3 Excavation 14
C 2-5 Underground installation 6
D 3-4 Foundation and Columns 5
E 4-5 Dummy 0
F 4-6 Construction of 2nd floor 6
G 4-7 Roof framing and Flooring 6
H 5-7 Ground floor slab 4
I 5-8 Mechanical and electrical services 12
69. Example 3 (cont’d)
Activity Node/Even
t
Description Duration
(days)
J 6-7 Construction of Exterior walls 12
K 7-8 Dummy 0
L 7-9 Construction of Interior Partitions 10
M 8-9 Mechanical and Electrical
equipment and fixtures
12
N 9-10 Painting and finish 8
a. Construct the PERT/CPM.
b. Determine the Critical Path and Critical Duration
c. Determine the Early Start (ES), Early Finish (EF), Latest Start (LS), and Latest Finish (LF)
d. Calculate the Slack/Float Time.
