Engineering Project
Management
Civil Engineering Department
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ENGINEERING
MANAGEMENT
An-Najah National University
Civil Engineering Department
Faculty of Engineering
Construction Engineering and
Management
Nabil Dmaidi
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ENGINEERING
MANAGEMENT
Your Expectations of Me
Be prepared
Be on time
Teach for full 50 minute period
Fair grading system
Front load the class work
Do not humiliate students
Practice golden rule
Provide real world examples
Make you think
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ENGINEERING
MANAGEMENT
Topics
1) Management Functions and introduction of construction project
planning and scheduling
2)Construction scheduling techniques
3)Preparation and usage of bar charts
4)Preparation and usage of the Critical Path Method (CPM)
5)Preparation and usage of Precedence Diagramming Method (PDM)
6)Issues relating to determination of activity duration
7)Contractual provisions relating to project schedules
8)Resource leveling and constraining
9)Time cost tradeoff
10)Schedule monitoring and updating.
11)Communicating schedule
12) Project control and earned value Control
13) claims, Safety and Quality control
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ENGINEERING
MANAGEMENT
Course Outline
Introduction and definitions
Float Analysis
Importance of Scheduling
The CPM Calculations
Networks, Bar Charts, and
Brief introduction on:
Imposed Finish Date and
Project Control and Earned
Value Analysis
Resource Allocation /Leveling
other CPM Issues
Time/Cost Trade-off
Precedence Networks
Updating Schedules
Time-Scaled Logic Diagrams
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What is the Project
ENGINEERING
MANAGEMENT
In order to understand project management, one must
begin with the definition of a project. A project can be
considered to be any series of activities and tasks that :.
● Have a specific objective to be completed within certain
specifications
● Have defined start and end dates
● Have funding limits (if applicable)
● Consume human and nonhuman resources (i.e., money,
people, equipment)
● Are multifunctional (i.e., cut across several functional
lines)
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OR
ENGINEERING
MANAGEMENT
‘‘a temporary endeavor undertaken to create
a unique product, service, or result’’
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Project Life Cycle
ENGINEERING
MANAGEMENT
9
Five Process group
Project initiation
● Selection of the best project given
resource limits
● Recognizing the benefits of the
project
● Preparation of the documents to
sanction the project
● Assigning of the project manager
ENGINEERING
MANAGEMENT
Project planning
Project execution
● Definition of the work
requirements
● Definition of the quality and
quantity of work
● Definition of the resources needed
● Scheduling the activities
● Evaluation of the various risks
Project monitoring and control
● Tracking progress
● Comparing actual outcome to
predicted outcome
● Analyzing variances and
impacts
● Making adjustments
● Negotiating for the project
team members
● Directing and managing the
work
● Working with the team
members to help them improve
Project closure
● Verifying that all of the work has
been accomplished
● Contractual closure of the contract
● Financial closure of the charge
numbers
● Administrative closure of the paper
work
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ENGINEERING
MANAGEMENT
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ENGINEERING
MANAGEMENT
Successful project management can then be defined as
having achieved the project objectives:
● Within Time
● Within Cost
● At the desired performance/Technology level
● While utilizing the assigned resources effectively
and efficiently
● Accepted by the customer
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What is Project Management
ENGINEERING
MANAGEMENT
Project management is the planning, organizing, directing,
and controlling of company resources for a relatively
short-term objective that has been established to complete
specific goals and objectives.
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ENGINEERING
MANAGEMENT
The potential benefits from project
management are:
● Identification of functional responsibilities
● Minimizing the need for continuous reporting
● Identification of time limits for scheduling
● Identification of a methodology for
trade-off analysis.
● Measurement of accomplishment
against plans
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ENGINEERING
MANAGEMENT
The above definition requires further comment. Classical
management is usually considered to have five functions
or principles:
● Planning
● Organizing
● Staffing
● Controlling
● Directing
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ENGINEERING
MANAGEMENT
Planning
– Where the organization wants to be in the
future and how to get there.
Organizing
– Follows planning and reflects how the
organization tries to accomplish the plan.
– Involves the assignment of tasks, grouping of
tasks into departments, and allocation of resources.
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ENGINEERING
MANAGEMENT
Leading
– The use of influence to motivate employees to
achieve the organization's goals.
– Creating a shared culture and values,
communicating goals to employees throughout
the organization, and infusing employees to
perform at a high level.
Controlling
– Monitoring employees' activities, determining if
the organization is on target toward its goals, and
making corrections as necessary
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Management Skills
ENGINEERING
MANAGEMENT
Conceptual Skill—the ability to see the
organization as a whole and the relationship
between its parts.
Human Skill—The ability to work with and
through people.
Technical Skill—Mastery of specific
functions and specialized knowledge
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Constraints of the project
ENGINEERING
MANAGEMENT
Project management is designed to manage or control
company resources on a given activity, within time, within
cost, and within performance. Time, cost, and performance
are the constraints on the project.
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Resources
ENGINEERING
MANAGEMENT
We have stated that the project manager must control company
resources within time, cost, and performance. Most companies have
six resources:
● Money
● Manpower
● Equipment
● Facilities
● Materials
● Information/technology
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ENGINEERING
MANAGEMENT
Actually, the project manager does not control
any of these resources directly, except perhaps
money (i.e., the project budget).
Resources are controlled by the line managers .
The project manager is responsible for
coordinating and integrating activities across
multiple, functional lines. The integration
activities performed by the project manager
include:
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ENGINEERING
MANAGEMENT
● Integrating the activities necessary to develop a project plan
● Integrating the activities necessary to execute the plan
● Integrating the activities necessary to make changes to the plan
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ENGINEERING
MANAGEMENT
Project Scheduling Planning,
Scheduling, and Control
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Planning and Scheduling
ENGINEERING
MANAGEMENT
Planning and scheduling are two terms that are
often thought of as synonymous
 They are not!
 Scheduling is just one part of the planning effort.
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ENGINEERING
MANAGEMENT
 Project planning serves as a foundation for several
related functions such as cost estimating, scheduling,
and project control.
 Project scheduling is the determination of the
timing and sequence of operations in the project
and their assembly to give the overall completion
time
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ENGINEERING
MANAGEMENT
Planning is the process of determining how a
project will be undertaken. It answers the
questions:
1. “What” is going to be done,
2. “how”,
3. “where”,
4. By “whom”, and
5. “when” (in general terms: start and finish).
Scheduling deals with “when” on a detailed
level… See Figure 1 .
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ENGINEERING
MANAGEMENT
How
much
What
when
The Plan
By
whom
where
How
Why
Figure 1 . Planning and Scheduling
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The Plan
ENGINEERING
MANAGEMENT
PMI defines project management plan as a ‘‘formal,
approved document that defines how the project is executed,
monitored and controlled”.
The plan can include elements that has to do with
scope, design and alternate designs, cost, time,
finance, land, procurement, operations, etc.
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ENGINEERING
MANAGEMENT
WHY SCHEDUALE PROJECTS ?
1- To calculate the project completion.
2- To calculate the start or end of a specific activity.
3-To expose and adjust conflict between trades or
subcontractor.
4- To predict and calculate the cash flow .
5-To evaluate the effect of changing orders ‘CH’ .
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ENGINEERING
MANAGEMENT
6- To improve work efficiency.
7- To resolve delay claims , this is important in
critical path method ‘CPM’ discussed later..
8- To serve as an effective project control tool .
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The Tripod of Good Scheduling System
ENGINEERING
MANAGEMENT
1. The Human Factor : A proficient scheduler or
scheduling team.
2. The Technology : A good scheduling computer
system (software and hardware)
3. The Management : A dynamic, responsive, and
supportive management.
 If anyone of the above three ‘‘legs’’ is missing, the system
will fail.
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Scheduling and project management
ENGINEERING
MANAGEMENT
Planning, scheduling, and project control are extremely
important components of project management.
project management includes other components :
• cost estimating and management,
• procurement,
• project/contract administration,
• quality management,
• and safety management.
 These components are all interrelated in different ways.
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ENGINEERING
MANAGEMENT
Bar (Gantt) Charts
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DEFINITION AND INTRODUCTION
ENGINEERING
MANAGEMENT
• A bar chart is ‘‘a graphic representation of project
activities, shown in a time-scaled bar line with no
links shown between activities’’
 The bar may not indicate continuous work from
the start of the activity until its end.
or
 Non continuous (dashed) bars are sometimes
used to distinguish between real work (solid line)
and inactive periods (gaps between solid lines)
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ENGINEERING
MANAGEMENT
• Before a bar chart can be constructed for a
project, the project must be broken into
smaller, usually homogeneous components,
each of which is called an activity, or a task.
Item
M 10
Activity
Mobilization
Bars ( Month or Year )
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ADVANTAGES OF BAR CHARTS
ENGINEERING
MANAGEMENT
1- Time-scaled
2- Simple to prepare
3- Can be more effective and efficient if CPM based
- Still the most popular method
4- Bars can be dashed to indicate work stoppage.
5- Can be loaded with other information (budget,
man hours, resources, etc.)
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ENGINEERING
MANAGEMENT
Bar Charts Loaded with More Info.
Such as : budget, man hours and resources .
500$
220$
400$
850$
140$
500$
900$
10
12
7
11
10
9
15
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DISADVANTAGES OF BAR CHARTS
ENGINEERING
MANAGEMENT
1- Does not show logic
2- Not practical for projects with too many
activities
- As a remedy, we can use bar charts to show:
1. A small group of the activities (subset)
2. Summary schedules
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Basic Networks
ENGINEERING
MANAGEMENT
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ENGINEERING
MANAGEMENT
DEFINITION AND INTRODUCTION
• A network is a logical and chronological graphic
representation of the activities (and events)
composing a project.
• Network diagrams are the preferred technique for
showing activity sequencing.
• Two main formats are the arrow and precedence
diagramming methods.
40
Two classic formats
AOA: Activity on Arrow
AON: Activity on Node
ENGINEERING
MANAGEMENT
Each task labeled with
Identifier (usually a letter/code)
Duration (in std. unit like days)
There are other variations of labeling
There is 1 start & 1 end event
Time goes from left to right
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ENGINEERING
MANAGEMENT
Arrow Diagramming Method (ADM)
1. Also called activity-on-arrow (AOA) network
diagram or (I-J) method (because activities are
defined by the form node, I, and the to node, J)
2. Activities are represented by arrows.
3. Nodes or circles are the starting and ending
points of activities.
4. Can only show finish-to-start dependencies.
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ENGINEERING
MANAGEMENT
Basic Logic Patterns for Arrow Diagrams
Node (Event) i
i
Node (Event) j
Activity Name
j
j>i
Each activity should have a unique i – j value
(a) Basic Activity
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ENGINEERING
MANAGEMENT
2
A
4
B
10
(b) Independent Activities
3
A
6
B
9
(c) Dependent Activities
12
44
ENGINEERING
MANAGEMENT
4
A
C
6
B
8
2
Activity C depends upon the completion of both Activities A & B
(d) A Merge
B
2
A
4
6
C
8
Activities B and C both depend upon the completion of Activity A
(e) A Burst
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ENGINEERING
MANAGEMENT
12
A
B
C
16
14
18
D
20
Activities C and D both depend upon the completion of Activities A and B
(f) A Cross
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Example
ENGINEERING
MANAGEMENT
Draw the arrow network for the project given next.
Activity
IPA
A
-
B
A
C
A
D
B
E
C,D
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ENGINEERING
MANAGEMENT
Solution :
B
30
10 A 20
D
E
40
C
50
48
Dummy activity (fictitious)
ENGINEERING
MANAGEMENT
* Used to maintain unique numbering of activities.
* Used to complete logic, duration of “0”
* The use of dummy to maintain unique numbering of
activities.
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ENGINEERING
MANAGEMENT
A
Divide node to correct
4
10
B
(a) Incorrect Representation
4
A
10
B
Dummy
11
(b) Correct Representation
50
Example
ENGINEERING
MANAGEMENT
Draw the arrow network for the project given next.
Activity
IPA
A
-
B
A
C
A
D
B,C
51
Solution :
ENGINEERING
MANAGEMENT
B
10 A 20
D
30
40
C
Improper solution
B
30
Dummy
40 D 50
10 A 20
C
proper solution
52
Example
ENGINEERING
MANAGEMENT
Draw the arrow network for the project given next.
Activity
IPA
A
-
B
A
C
A
D
B
E
B,C
F
C
53
ENGINEERING
MANAGEMENT
Solution :
B
30
D
Dummy 1
10 A 20
50 E
Dummy 2
C
40
F
60
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ENGINEERING
MANAGEMENT
Removal of Redundant Dummies
Original Diagram
Diagram after removal
of redundant dummies
(a)
A
B
A
B
(b)
A
B
A
B
C
C
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ENGINEERING
MANAGEMENT
Original Diagram
(c)
(d)
Diagram after removal
of redundant dummies
A
C
A
C
B
E
B
E
A
C
A
C
B
E
B
E
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ENGINEERING
MANAGEMENT
Activity
Depends Upon
Immediately Preceding
Activity (IPA)
A
B
C
----A
A, B
----A
B
A
B
Redundant
Relationship
C
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Activity List with Dependencies:
ENGINEERING
MANAGEMENT
Activity
A
B
C
D
E
F
G
H
J
K
L
M
Description
Site Clearing
Removal of Trees
Excavation for Foundations
Site Grading
Excavation for Utility Trenches
Placing formwork & Reinforcement
Installing sewer lines
Pouring concrete
Obtain formwork & reinforcing steel
Obtain sewer lines
Obtain concrete
Steelworker availability
Depends Upon
--------A
A, B, C
A, B, C
B, C, J, M
B, C, D, E, K
D, E, F, G, L
-----------------
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Removing Redundant Relationships:
ENGINEERING
MANAGEMENT
Activity
A
B
C
D
E
F
G
H
J
K
L
M
Description
Site Clearing
Removal of Trees
Excavation for Foundations
Site Grading
Excavation for Utility Trenches
Placing formwork & Reinforcement
Installing sewer lines
Pouring concrete
Obtain formwork & reinforcing steel
Obtain sewer lines
Obtain concrete
Steelworker availability
Depends Upon
--------A
A, B, C
A, B, C
B, C, J, M
B, C, D, E, K
D, E, F, G, L
-----------------
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ENGINEERING
MANAGEMENT
L
J
M
A
20
10
F
15
B
5
25
C
G
E
D
35
30
K
AOA Representation
40
H
45
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ENGINEERING
MANAGEMENT
NODE NETWORKS MTHOD (AON)
Link
Activity number
10
A
Activity name
20
B
a) Independent Activities
10
A
Link
20
B
b) Dependent Activities
B depends on A
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ENGINEERING
MANAGEMENT
10
A
30
C
40
D
C depends on A & B
D depends on C
20
B
c) A Merge Relationship
10
A
20
B
30
C
40
D
d) A Burst Relationship
B depends on A
C depends on B
D depends on B
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ENGINEERING
MANAGEMENT
A
D
A
Start
Dummy
B
C
E
D
Finish
Dummy
B
C
e) Start & Finish Dummy Activities
E
63
Example
ENGINEERING MANAGEMENT
Draw the arrow network for the project given next.
Activity
IPA
A
-
B
A
C
A
D
B
E
C,D
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ENGINEERING MANAGEMENT
Solution :
B
D
A
E
C
65
Example
ENGINEERING MANAGEMENT
Draw the arrow network for the project given next.
Activity
IPA
A
-
B
A
C
A
D
B,C
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ENGINEERING MANAGEMENT
Solution :
B
A
D
C
67
Example
ENGINEERING MANAGEMENT
Draw the arrow network for the project given next.
Activity
IPA
A
-
B
A
C
A
D
B
E
B,C
F
C
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ENGINEERING MANAGEMENT
Solution :
B
A
D
E
C
F
PF
69
Lags and Leads
ENGINEERING MANAGEMENT
In some situations, an activity cannot start until a
certain time after the end of its Predecessor.
Lag is defined as a minimum waiting period
between the finish (or start) of an activity and the
start (or finish) of its successor.
Arrow networks cannot accommodate lags. The
only solution in such networks is to treat it as a real
activity with a real duration, no resources, and a $0
budget.
70
Examples
ENGINEERING MANAGEMENT
3
Place Concrete
3
Strips Forms
2
A lag in a node network
Place Concrete
Cure Concrete
A lag in an arrow network
Strips Forms
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ENGINEERING MANAGEMENT
The term lead simply means a negative lag. It is
seldom used in construction. In simple language: A
positive time gap (lag) means ‘‘after’’ and a negative
time gap (lead) means ‘‘before.’’
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ENGINEERING MANAGEMENT
Recommendations for Proper Node Diagram Drawing
Incorrect
Correct
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ENGINEERING MANAGEMENT
A
B
A
B
A
B
A
B
Improper
proper
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ENGINEERING MANAGEMENT
Improper
Proper
75
ENGINEERING MANAGEMENT
Improper
Proper
76
ENGINEERING MANAGEMENT
A
A
B
B
PS
C
C
Improper
Proper
(a) Do not start a network with more than one node
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ENGINEERING MANAGEMENT
Improper
A
A
B
B
C
C
Proper
(a) Do not end a network with more than one node
PF
78
The Critical Path Method
(CPM)
79
Introduction
ENGINEERING MANAGEMENT
Suppose you decide with your friend to go in
hunting trip.
You must do specific activity such that the trip well
be at the right way. The following activity must be
done.
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ENGINEERING MANAGEMENT
From chart you can see that the 3rd activity (preparing the
jeep) have the longest period of time any delay with this
activity leads to delay in the trip this activity is a “critical
activity”
Critical activity : An activity on the critical path any delay on
the start or finish of a critical activity will result in a delay in
the entire project
Critical path : The longest path in a network from start to
finish
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ENGINEERING MANAGEMENT
Steps Required To Schedule a Project
The preparation of CPM includes the following four steps:
1- Determine the work activities:
The project must be divided into smaller activities
or tasks .
The activity shouldn’t be more than 14-20
days (long durations should be avoided)
Use WBS in scheduling by using an order of
letters and numbers
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ENGINEERING MANAGEMENT
2- Determine activity duration:
Duration = Total Quantity / Crew Productivity
The productivity has many sources :
1. The company
2. The market
3. Special books
Note: The scheduler must be aware about the non-working days ,
such as holydays or rain days, etc……
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ENGINEERING MANAGEMENT
3- Determine the logical relationships :
This step is a technical matter and obtained
from the project manager and technical team,
and logical relationships shouldn’t confused
with constraints
4- Draw the logic network and perform the CPM
calculations
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ENGINEERING MANAGEMENT
5-Reiew and analyze the schedule:
1. review the logic
2. Make sure the activity has the correct predecessor
3. make sure there is no redundant activity
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ENGINEERING MANAGEMENT
6- Implement the schedule:
Definition: take the schedule from paper to the execution.
7-Monitor and control the schedule:
Definition: comparing what we planed with what
actually done.
8-Revise the database and record feedback.
9-Resource allocation and leveling.
(will discuss in chapter 6)
86
Example
ENGINEERING MANAGEMENT
Draw the logic network and perform the CPM calculations for the
schedule shown next.
Activity
IPA
Duration
A
-
5
B
A
8
C
A
6
D
B
9
E
B,C
6
F
C
3
G
D,E,F
1
87
Forward pass calculations
ENGINEERING MANAGEMENT
In mathematical terms, the ES for activity j is as follows :
ESj =max( EFi )
where (EFi) represents the EF for all preceding activities.
Likewise, the EF time for activity j is as follows :
EF j= ESj + Dur j
where Dur j is the duration of activity j
Forward pass: The process of navigating through a
network from start to end and calculating the completion date
for the project and the early dates for each activity
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ENGINEERING MANAGEMENT
Solution :
0,5
A
5
5,13
B
8
13,22
D
9
13,19
E
6
5,11
C
6
22,23
G
1
11,14
F
3
89
Backward pass calculations
ENGINEERING MANAGEMENT
In mathematical terms, the late finish LF for activity j is as follows :
LFj =min(LSk(
where (LSk) represents the late start date for all succeeding
activities.
Likewise, the LS time for activity j (LS j) is as follows :
LS j= LFj - Dur j
where Dur j is the duration of activity
Backward pass: The process of navigating through a network
from end to start and calculating the late dates for each activity. The
late dates (along with the early dates) determine the critical activities,
the critical path, and the amount of float each activity has.
90
ENGINEERING MANAGEMENT
Solution :
0,5
A
5
0,5
5,13
B
8
5,13
5,11
C
6
10,16
13,22
D
9
13,19 13,22
E
6
16,22
11,14
F
3
19,22
CPM ( ES = LS , EF = LF , TF = FF = 0)
22,23
G
1
22,23
91
Four Types Of Floats
ENGINEERING MANAGEMENT
There are several types of float. The simplest and most
important type of float is Total Float (TF)
 Total float (TF): The maximum amount of time
an activity can be delayed from its early start
without delaying the entire project.
TF = LS – ES
or
TF = LF - EF
or
TF = LF - Dur - ES
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ENGINEERING MANAGEMENT
 Free Float: may be defined as the maximum
amount of time an activity can be delayed without
delaying the early start of the succeeding activities
FFi = min(ESi+1) - EFi
where min (ESi+1) means the least (i.e., earliest) of the early start
dates of succeeding activities
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ENGINEERING MANAGEMENT
In the previous example we can find the free float and total float for
each activity as the following :
Activity C’s free float, FF = 11 - 11 = 0 days
And
Activity C’s total float, TF =16 - 11= 5 days …… and so on.
Activity
Duration
ES
EF
LS
LF
TF
FF
A
5
0
5
0
5
0
0
B
8
5
13
5
13
0
0
C
6
5
11
10
16
5
0
D
9
13
22
13
22
0
0
E
6
13
19
16
22
3
3
F
3
11
14
19
22
8
8
G
1
22
23
22
23
0
0
 Critical activity
 Note : We must always realize that FF ≤ TF
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ENGINEERING MANAGEMENT
 Interfering float: may be defined as the maximum
amount of time an activity can be delayed without
delaying the entire project but causing delay to the
succeeding activities.
TF = FF - Int. or
Int. F = TF - FF
 Independent float (Ind. F): we may define it as
the maximum amount of time an activity can be
delayed without delaying the early start of the
succeeding activities and without being affected
by the allowable delay of the preceding activities.
Ind. Fi = min(ESi+1) – max(LFi-1) – Duri
Note: make sure that Ind. F ≤ FF
95
Node Format
ES
ENGINEERING MANAGEMENT
Activity ID
EF
Activity Name
LS
TF
Duration
LF
FF
96
ENGINEERING MANAGEMENT
Event Times in Arrow Networks
 The early event time, TE, is the largest (latest) date
obtained to reach an event (going from start to finish).
 The late event time, TL, is the smallest (earliest) date
obtained to reach an event (going from finish to start).
Examples
Perform the CPM calculations, including the event times, for the arrow
network shown below.
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ENGINEERING MANAGEMENT
A
10
20 8D
d1
10
B
E
30 9
5
C
7
60
G5
H
50
8
40 4F
Arrow network for example
d2
70
98
ENGINEERING MANAGEMENT
The preceding logic is similar to that of the forward and backward
passes: When you are going forward, pick the largest number.
When you are going backward, pick the smallest number.
TEi
i
TEj
Act. Name
Dur.
j
TLj
TLi
CPM
99
ENGINEERING MANAGEMENT
10
A
(0,10)
10 (0,10)
D
20 8
(10,18)
(11,19)
B
5
d1
(0,5)
(5,10)
7
0
C (0,7)
7 (8,15)
40 4F
15
(19,24)
60
G5 (22,27)
(19,27)
H
50
27
10
0
10
24
10
(10,19)
E
30 9 (10,19)
10
(7,11)
(15,19)
19
8
19
(19,27)
d2
27
70
27
100
ENGINEERING MANAGEMENT
Float Calculations From Event Times
Total Float
TFij = TLj - TEi - Tij
Example ( In the previous network )
TF40-50 = TL50 – TE40 – T40-50
= 19 – 7 – 4 = 8
101
ENGINEERING MANAGEMENT
Free Float
FFij = TEj - TEi – Tij
Example
FF40-50 = TE50 – TE40 – T40-50
= 19 – 7 – 4 = 8
102
Interfering Float
INTFij = TLj – TEj
Example
INTF40-50 = TL50 – TE50
= 19 – 19 = 0
Independent Float
INDFij= TEj – TLi - Tij
Example
INDF40-50 = TE50 – TL40 – T40-50
= 19 – 15 – 4 = 0
ENGINEERING MANAGEMENT
103
ENGINEERING MANAGEMENT
Summary
TEi
i
TLi
Direction
TEj
T
j
TLj
Float
TF
FF
Int. F
Ind. F
104
Definitions
ENGINEERING MANAGEMENT
Activity, or task: A basic unit of work as part of the total project
that is easily measured and controlled. It is time- and resource
consuming.
Backward pass: The process of navigating through a network from
end to start and calculating the late dates for each activity. The late
dates (along with the early dates) determine the critical activities,
the critical path, and the amount of float each activity has.
Critical activity: An activity on the critical path. Any delay in the
start or finish of a critical activity will result in a delay in the entire
project.
Critical path: The longest path in a network, from start to finish,
including lags and constraints.
105
ENGINEERING MANAGEMENT
Early dates: The early start date and early finish date of an activity.
Early finish (EF): The earliest date on which an activity can finish within project
constraints.
Early start (ES): The earliest date on which an activity can start within project
constraints.
Event: A point in time marking a start or an end of an activity. In contrast to an
activity, an event does not consume time or resources.
Forward pass: The process of navigating through a network from start to end and
calculating the completion date for the project and the early dates for each activity.
Late dates: The late start date and late finish date of an activity.
Late finish (LF): The latest date on which an activity can finish without extending
the project duration.
Late start (LS): The latest date on which an activity can start without extending the
project duration.
106
Precedence Diagram
107
ENGINEERING MANAGEMENT
The Four Types Relationships
Activities represented by nodes and links that
allow the use of four relationships:
1) Finish to Start – FS
2) Start to Finish – SF
3) Finish to Finish – FF
4) Start to Start – SS
108
ENGINEERING MANAGEMENT
Finish to Start (FS) Relationship
. The traditional relationship between activities.
. Implies that the preceding activity must finish
before the succeeding activities can start.
. Example: the plaster must be finished before the
tile can start.
Plaster
Tile
109
ENGINEERING MANAGEMENT
Star to Finish (SF) Relationship
. Appear illogical or irrational.
. Typically used with delay time OR LAG.
. The following examples proofs that its logical.
Erect
formwork
steel
reinforcement
Pour
concrete
5
SF
Order
concrete
110
ENGINEERING MANAGEMENT
Finish to Finish (FF) Relationship
• Both activities must finish at the same time.
• Can be used where activities can overlap to a
certain limit.
Erect
scaffolding
Remove
Old paint
FF/1
sanding
FF/2
painting
inspect
Dismantle
scaffolding
111
ENGINEERING MANAGEMENT
Start to Start (SS) Relationship
• This method is uncommon and non exists in
project construction .
Clean surface
Spread grout
SS
Set tile
Clean floor area
112
ENGINEERING MANAGEMENT
Advantages of using Precedence Diagram
1. No dummy activities are required.
2. A single number can be assigned to identify each
activity.
3. Analytical solution is simpler.
113
Calculation
1) forward calculations
EF = ES + D
Calculate the Lag
LAGAB = ESB – EFA
Calculate the Free Float
FF = Min. (LAG)
ENGINEERING MANAGEMENT
114
ENGINEERING MANAGEMENT
2) Backward calculations
For the last task
LF=EF ,
if no information deny that.
LS=LF-D
Calculate Total Float
TF = LS – ES OR
LF – EF
TFi = Min (lag ij + TFj )
Determine the Critical Path
115
Example
ENGINEERING MANAGEMENT
1) Forward pass calculations
4) Backward pass calculations
5) Calculate total Float (TF = LS – ES OR LF – EF)
A
1
2
B
0
1
2
0 0 2
11
1
9
0
D
0
2
11
0 11
16
5
0 0 16
7
E
0
5
7
0 3 10
11
5
4
0
H
0
16
20
20 0 0 20
21
4
5
0
2
16
11
4
C
F
0
1
20
0 0 21
3
G
0
10
11
3 14
17
6
3
14
3 20
2) Calculate the Lag ( LAGAB = ESB – EFA)
3) Calculate the Free Float (FF) FF = min.( LAG)
ES
Dur. LS
EF FF TF
115LF
116
ENGINEERING MANAGEMENT
6) Determine the Critical Path
A
1
2
B
0
1
2
0 0 2
11
1
9
0
D
0
2
11
0 11
16
5
0 0 16
7
E
0
5
7
0 3 10
11
5
4
0
H
0
16
20
20 0 0 20
21
4
5
0
2
16
11
4
C
F
0
1
20
0 0 21
3
G
0
10
11
3 14
17
6
3
14
3 20
The critical path passes through the critical activities where TF = 0
ES
Dur. LS
EF FF TF
116LF
117
Resource Allocation and
Resource Leveling
118
ENGINEERING MANAGEMENT
CATEGORIES OF RESOURCES
 Labor
 Materials
 Equipment's.
119
Schedule Updating and
Project Control
120
Schedule Updating and Project Control
ENGINEERING MANAGEMENT
The most important use of schedules is project control :
the scheduler compares actual performance with baseline
performance.
What is Project Control
Project control comprises the following continuous process
1. monitoring work progress .
2.comparing it with the baseline schedule and budget.
3.finding any deviations .
4.taking corrective actions.
121
Schedule updating
ENGINEERING MANAGEMENT
Schedule updating is just one part of the project
control process.
Schedule updating must reflect
 Actual work , and
 involves change orders (CO) .
122
What is a baseline schedule?
ENGINEERING MANAGEMENT