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An-Najah National University
Civil Engineering Department
Faculty of Engineering
Engineering Management
Course
Nabil Dmaidi
Nabil Dmaidi 1
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
Nabil Dmaidi 2
Topics
1) 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) Management function.
12) Communicating schedule
13) Cost Control
14) Safety and Quality control
Nabil Dmaidi 3
Management Functions
Planning
– Where the organization wants to be in the
future and how to get there.
Nabil Dmaidi 4
Management Functions
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.
Nabil Dmaidi 5
Management Functions
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.
Nabil Dmaidi 6
Management Functions
Controlling
– Monitoring employees' activities, determining
if the organization is on target toward its goals,
and making corrections as necessary.
Nabil Dmaidi 7
Management Skills
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.
Nabil Dmaidi 8
Decision Making
Decision: a choice made from two or more
alternatives.
Part of all four managerial functions
Decisions are made on the basis of:
– Rationality
– Bounded Rationality
– Intuition
Nabil Dmaidi 9
Rationality
Problem is clear and unambiguous.
Single goal.
All alternatives are known.
Clear and constant preferences.
Maximum payoff.
The decision is in the best interest of the
organization—not the manager.
Nabil Dmaidi 10
MANAGEMENT HIERARCHY
Management Level Responsibility
TOP MANAGEMENT LONG RANGE PLANNING
MIDDLE MANAGEMENT SHORT TERM PLANNING
SUPERVISORS EXECUTION
Nabil Dmaidi 11
Project Life Cycle
Definition Planning Execution Delivery
Level of effort
1. Goals 1. Schedules 1. Status reports 1. Train customer
2. Specifications 2. Budgets 2. Changes 2. Transfer documents
3. Tasks 3. Resources 3. Quality 3. Release resources
4. Responsibilities 4. Risks 4. Forecasts 4. Reassign staff
5. Teams 5. Staffing 5. Lessons learned
Nabil Dmaidi 12
Phase One
Definition Stage
– Defining Specifications
– Establishing objectives
– Determining tasks
– Forming teams
– Assigning responsibilities
Low level of effort
Nabil Dmaidi 13
Phase Two
Planning Stage
– Estimating time and cost
– Scheduling activities and resources
– Identifying and determining risks
– Assigning teams
Level of effort increases
Nabil Dmaidi 14
Phase Three
Execution Stage
– Producing physical product
– Collecting data
– Monitoring project performance
– Identifying the changes
– Forecasting new measures
Highest level of effort
Nabil Dmaidi 15
Phase Four
Delivery Stage
– Training customer
– Transferring documents
– Releasing resources
– Reassigning staff
– Documenting lessens learned
Low level of effort
Nabil Dmaidi 16
Integrated Management of Projects
Customer
Political, social, economic, Management, facilities
Environmental analysis
and technological Financial conditions
External Internal
Firm
Signal mission, Signal
Opportunities goals, strategies Weaknesses
and Threats and strengths
Priorities
Projects
System Environment
and Culture
Scope
Organization
Work Breakdown
Networks Leadership
Resources Teams
Cost Partners
Project Implementation
Nabil Dmaidi 17
Definition of a Project
From the Project Management Institute:
“A temporary endeavor
undertaken to create a unique
product or service”
Nabil Dmaidi 18
What is a Project?
Temporary
Unique
There is an end
Duration is finite
Characteristics are progressively elaborated
Nabil Dmaidi 19
Examples of projects include:
• Developing a new product or service.
• Effecting a change in structure, staffing, or style of
an organization.
• Designing a new transportation vehicle.
• Developing or acquiring a new or modified
information system.
• Constructing a building or facility.
• Running a campaign for political office.
• Implementing a new business procedure or process
Nabil Dmaidi 20
Examples of a Project
Installing a computer network in a building
Opening a new store/factory
Automating an assembly line
Design a new car model
Introducing a new car model
Building a bridge
Nabil Dmaidi 21
İn the construction
Project Management is the sum of all
activities such as Planning,organising
,implementing and controlling a project
in order to meet the client’s expectation
from start to finish within the planned
period, budget and quality.”
Nabil Dmaidi 22
The purpose of Project
Management
The purpose of Project Management is to
foresee or predict as many of the dangers
and problems as possible and to
Plan
Organize
Coordinate
Control
Nabil Dmaidi 23
The components of Project Management
Scope
Time
Cost
Quality
Human Resource
Communications
Risk
Procurement
Nabil Dmaidi 24
Project Constraints
Time
Cost
Quality
Nabil Dmaidi 25
Control
The heart of the project management system is
CONTROLLING the execution of the works.
The purpose of this control is to determine and
predict deviations in a project so corrective actions
can be taken.
The milestones of the control process are as follows:
To determine the aim
Determine the control standarts
To determine the strategic points
To evaluate the actual results and to compare to the
planned
Nabil Dmaidi 26
İt defines the quality of the management
Nabil Dmaidi 27
Skills for Project Management
Good Planning
Conflict Resolution
Creativity
Flexibility
Negotiation
Communication
– Client
– Subcontractors
– Team
Nabil Dmaidi 28
Dimensions of Project Management
Performance
Money
Time
Plan should consider all of these before
starting
Manager needs to track them during project
Nabil Dmaidi 29
Project Management
Project Management is the Science and Art
of Enhancing the Probability of Success by
Inspired Leadership using Structured
Techniques for Planning that Integrate
Technical Performance, Scheduling and
Budgeting (1).
(1)-Fundamentals of Space Systems - Pisacane and Moore
Nabil Dmaidi 30
Project Management
Guide and Direct the effort
– Science and Art
– Enhancing the Probability of Success
– Leadership (Inspired or not)
– Structured Techniques for Planning
CriticalPath — the path of a network that requires
the longest period of time to complete
Integrate Technical Performance, Scheduling and
Budgeting
Nabil Dmaidi 31
Objectives of a Project
Management Structure
Deliver a product that meets the
requirements of the project’s objectives.
(Systems Engineering)
Deliver a product that meets the
requirements of the contract delivery
schedule
For commercial companies: meet profit
objectives
Nabil Dmaidi 32
Prerequisites
Must have adequate resources and facilities
available to meet the delivery schedule
Terms of the contract must be realistic and
adequate to cover the cost to perform under
the contract
Nabil Dmaidi 33
Project Manager’s Authority
Technical Decisions
– Directing the design approach
– Selecting subsystems or components
– Identifying type and scope of tests
Commercial Decisions
– Make or Buy
– Selecting/recommending subcontractors or
vendors
Nabil Dmaidi 34
Continued
Administrative Decisions
– Selecting and assigning personnel
– Scheduling personnel, resources and equipment
Monetary Decisions
– Determining the expenditure of funds
Nabil Dmaidi 35
Project Management Tools
PERT/GANTT Charts
– Program Evaluation Review Technique
— element of work
Activity
Event— Start or Completion Point
• Network — Graphic representation of a program
consisting of activities and events which are shown as
interconnected paths
Nabil Dmaidi 36
Planning
The road to project failure is paved with poor
plans
PLANNING: Influencing the future by
making decisions today based on
missions, needs and objectives.
It is an art not science.
Nabil Dmaidi 37
Categories of planning:
Time
Cost
Resources
Quality
Contingency
Nabil Dmaidi 38
Time Planning
When to start
when to finish
Time plans will be transformed to schedule
(time scale)
Nabil Dmaidi 39
Time planning steps
1) Divide project into component parts
2) Sequencing component parts in order of
accomplishment
3) Assign durations to each component
part
Nabil Dmaidi 40
Cost Planning
Allocating direct and indirect costs to the project
components
Summation of components costs. Total cost
should equal the budget.
( cost / schedule integration)
Nabil Dmaidi 41
Resources Planning
Construction Resources includes:
money
Material
Human resources
Equipments and tools
Resources should be planned considering the budget.
Attention to critical resources for project success
Nabil Dmaidi 42
Quality Planning
what is the minimum accepted quality?
Should I exceed the required quality?
How can I achieve this quality?
Nabil Dmaidi 43
Contingency (Risk) Planning
Planning for variability and uncertainty
“What if” planning to include items subject
to variability which are significantly impact
project cost and time
Nabil Dmaidi 44
Integrating Planning
Integration of time, cost and resource
planning against the same basic structure
(WBS)
Resource budgeting against time
Cost budgets plotted against time
Nabil Dmaidi 45
Thousands of tasks
The psychologists say our brains can
normally comprehend around 7-9 items
simultaneously.
So, divide and subdivide the project.
Nabil Dmaidi 46
The WBS
(Work Breakdown Structure)
IT is used to break down the project from
one main and relatively big entity into
smaller, defined, manageable and
controllable units, usually called work
groups or tasks, or, at the finest level of
detail (which is undesirable) activities
Nabil Dmaidi 47
Take care!!!
The deeper you go into the lower levels of
the WBS, the more detailed knowledge
you’ll need to know.
A good rule of thumb is the rule of 1-5-5-5,
which entails that each level be broken
down into a maximum of five lower levels.
Nabil Dmaidi 48
Who develops the WBS?
A WBS is developed by the A/E at the end
of the design phase
and/or by the bidders during the proposal
(procurement phase)
Nabil Dmaidi 49
The CWBS
(Contract Work breakdown Structure )
After contract award, the project manager
expands the WBS into a contract work
breakdown structure (CWBS).
as the initial step in the PLANNING
process.
Nabil Dmaidi 50
The CWBS
The extended CWBS must include the
levels at which required reporting
information is summarized for submittal to
the Owner
Nabil Dmaidi 51
Uses of the WBS
The WBS is used to report program status
externally to the Owner.
The CWBS is used internally to plan the
program in detail and to collect status
information on a periodic basis for the
lowest level of the CWBS, namely the
schedule activities.
The basis for technical planning and project
achievement.
Nabil Dmaidi 52
The CWBS
it is a major task to undo.
Why???
Because cost collections begins at a CWBS
element,
Nabil Dmaidi 53
WBS/CWBS
The individuals assigned the responsibility
for WBS/CWBS development should never
lose sight of the fact that the WBS is used
for technical planning and status
achievement.
Nabil Dmaidi 54
House
Level 1 1.0
Structural fine Electrical
Level 2 Work works Works
1.1 1.2 1.3
Sub- Super- Doors & Light
Finishing Windows Conduiting
Level 3 Structure Structure 1.21 frames 1.3.1
Fittings
1.1.1 1.1.2 1.2.2 1.3.2
Earthwork Foundation Columns Roof slabs Plaster Floor tile Level 4
1.1.1.1 1.1.1.2 1.1.2.1 1.1.2.2 1.2.1.1 1.2.1.2
Excavation Backfilling
1.1.1.1.1 1.1.1.1.2 Level 5
Nabil Dmaidi 55
Conclusion
The work breakdown structure defines the
product elements (work packages).
And their interrelations to each other and to
the product.
The WBS mostly ends with project tasks.
Using the tasks you can extract project’s
activities.
Nabil Dmaidi 56
Construction scheduling
What is the difference between a schedule
and a Plan?
The schedule: putting the plan in time scale.
Nabil Dmaidi 57
Most Common Scheduling
methods
common scheduling methodologies:
Bar Charts (Gantt Charts)
Critical Path Method (CPM)
PERT (Project Evaluation & Review
Techniques)
Linear Scheduling Method (LSM)
Nabil Dmaidi 58
Construction scheduling
To be able to build up a successful schedule. You
need to:
1) Define activities
2) Order activities
3) Establish activities relationships
4) assign durations to activities
5) resources and costs allocation
6) calculate early and late start/finish times
7) calculate float values and identify the critical
path
Nabil Dmaidi 59
Bar Chart or Gantt chart
Bar chart is a collection of activities listed
vertically, and the horizontal scale
represents the time.
First applied by HENRY GANTT
Nabil Dmaidi 60
Typical Bar / Gantt chart
Nabil Dmaidi 61
Advantages of Bar / Gantt Chart
Plan, schedule and progress are all depicted
graphically on a single chart
Easily read
Provides simple way to schedule small projects
Provides summary display of more detailed
plans and schedules
Best used for management briefings
Nabil Dmaidi 62
Disadvantages of Bar / Gantt Chart
Planning and scheduling are considered
simultaneously
Activity dependencies cannot adequately be
shown
Difficult to determine how activity progress
delays affect project completion
Difficult to establish and maintain for large
projects
Nabil Dmaidi 63
Critical Path Method (CPM)
Two basic methods of analysis:
1) ADM -- Arrow Diagramming Method
Activity On Arrow (AOA) or I-J Method
2) PDM -- Precedence Diagramming Method
Activity On Node (AON) Method
Nabil Dmaidi 64
Types of construction Constraints
1) Physical constraints.
2) Resource constraints.
3) Safety constraints.
4) Financial constraints.
5) Environmental constraints.
6) Management constraints.
7) Contractual constraints.
8) Regulatory constraints.
Nabil Dmaidi 65
Physical constraints.
Physical constraints exist due to physical
process of construction.
Physical constraints defined by “HOW” the
project is to be carried out. ( Method of
construction).
You need to erect formwork before you can
cast concrete.
Nabil Dmaidi 66
Resource constraints
These constraints imposed wherever tow activities
cannot be carried out simultaneously because
insufficient resources are available.
E.g. Tow activities require a crane to be performed
and you have just one crane. So, they should not
be performed at the same time.
E.g. The amount of required concrete per day
exceeds the production capacity of a batch plant.
Nabil Dmaidi 67
Safety constraints.
Safety constraints imposed by safety requirements
through performing the work.
Sometime imposes that tow activities could not be
performed at the same time due to non-safe work
conditions. ( E.g. overhead and ground level work
at the same area.)
Imposes specific sequence of the work. (e.g.
erecting of scaffolding before external paints can
start)
Imposes non-working days due to extremely hot
or cold days.
Nabil Dmaidi 68
Financial constraints
Financial constraints: high cost activities
could be delayed due to non-availability of
cash requirements during construction.
The amount of cost a company can pay
within a specific period of time usually
limited. So, try to avoid overlap between
high cost activities.
Nabil Dmaidi 69
Environmental constraints.
Environmental constraints include
restrictions to the work to avoid
environmental violations.
E.g. not working in certain area during
specific times to avoid affecting
proliferation of eagles, fish run.
Nabil Dmaidi 70
Management constraints.
Management constraints reflect decisions of
management that result in a reasonable
benefit of the company.
E.g. the management decided to borrow
from your project resources to be utilized in
another project.
E.g. the management decided to extend the
new year holiday another 2 days.
Nabil Dmaidi 71
Contractual constraints
The owner may impose constraints on the
construction process.
E.g. the owner may require a particular phase of
the project to be fully completed and occupied
before start construction of next phase.
And he may require to minimize the noise and
dust because that portion is occupied and in
operation.
Nabil Dmaidi 72
Regulatory constraints.
These type of constraints related to the
regulations of the area of construction.
Imposed by municipality, government, etc.
E.g. if the construction site in the
downtown, heavy vehicles like concrete
mixers prohibited to access the site in a
specific times of the day. So, you can just
cast concrete at night.
Nabil Dmaidi 73
Impacts of constraints on the
network
In the initial definition of the network, it is
desirable to minimize the number of
constraints, because excessive constraints
have the following impact of the project.
1) Reduce scheduling flexibility.
2) Lengthen project duration.
3) Generally increase project costs.
4) Confuse basic scheduling logic.
Nabil Dmaidi 74
Impacts of constraints on the
network
The imposition of constraints in the network
results in linear ordering of activities.
Which is not desired. (recall: the linear
order of activities prolong the project
duration and set most of the activities as
critical).
Nabil Dmaidi 75
Impacts of constraints on the
network
Only physical constraints should be
considered in the early preparation of the
network.
Other constraints can be deferred until
actual schedule of activities. Where it can
be determined that :
1) the constraints are not met by the
schedule.
2) It can be addressed by shifting of activities
within their available float time.
Nabil Dmaidi 76
Resources Allocation & Leveling
So far, the network analysis has been considered
using one resource only which is time.
Construction activities in practice use other
resources like labor, material, equipment and
money.
Moreover, the network analysis considered no
limitations of the traditional resources (labor,
material, equipment and money) which is not the
case in practice.
Nabil Dmaidi 77
Activities Relationships
Types of relations between activities:
1) Finish to start – FS
2) Start to Finish – SF
3) Finish to Finish – FF
4) Start to Start - SS
Nabil Dmaidi 78
1) 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.
Nabil Dmaidi 79
Finish to start with delay relationship
Pour concrete Concrete curing Deshuttering
1 day 28 days 2 days
Concrete curing an activity which consumes no resources other than time
FS/28
Pour concrete Deshuttering
1 day 2 days
28 days is delay time or LAG means that: deshuttering can start 28 days after
Concrete has been poured
Nabil Dmaidi 80
3) Star to Finish – SF relationship
Appear illogical or irrational.
Typically used with delay time OR LAG.
The following examples proofs that its
logical.
Nabil Dmaidi 81
2) Star to Finish – SF relationship
steel
Erect formwork reinforcement Pour concrete
SF5
Order concrete
The concrete supplier stipulates 5 days order before delivery.
Nabil Dmaidi 82
3) Finish to Finish – FF relationship
Both activities must finish at the
same time.
Can be used where activities can
overlap to a certain limit.
Nabil Dmaidi 83
Finish to Finish – FF relationship
Set flagpole Position flagpole
In the hole In the hole
FF
Backfill
hole
Nabil Dmaidi 84
Finish to Finish with delay relationship
Erect Remove
scaffolding Old paint
FF/1
sanding
FF/2
Dismantle
painting inspect scaffolding
Nabil Dmaidi 85
4) Start to Start – SS relationship
Clean surface Spread grout
SS
Set tile Clean floor area
Nabil Dmaidi 86
The Four Activity Times -
Arrow Diagram Notation
Activity
i j
Tij
(a)
ESDij EFDij LSDij LFDij
Activity ij Activity ij
Tij Tij
Time
Available
(b)
Nabil Dmaidi 87
Forward Pass Rules
Rule 1
The initial project event is assumed to occur at time zero
Rule 2
All activities are assumed to start as soon as possible,
that is , as soon as all the predecessor activities are
completed.
Rule 3
The early finish time of an activity is merely the sum of
its early start date and the estimated activity duration.
EFDij = ESDij + Tij
Nabil Dmaidi 88
Forward Pass Rules (cont.)
Rule 4
The late start date LSDij is found by subtracting
the activity duration Tij from the late finish date
LFDij
LSDij = LFDij - Tij
Nabil Dmaidi 89
Forward Pass Comput at ions - Remodeling Chemical Laborat ory
i j Act ivit y Descript ion T (Days) ESD EFD
2 4 St rip room 3 0 3
2
2 1 Obt ain fume hood 10 0 10
4
2 1 Obt ain cabinet 10 0 10
2 20 Obt ain chemical sink 10 0 10
2 24 Paint er availabilit y 20 0 20
2 28 Obt ain vinyl floor covering 5 0 5
4 6 Rough-in plumbing and elect rical 5 3 8
4 8 Replace exist ing fume duct 3 3 6
6 8 Dummy 0 8 8
0
6 1 Repair floor 1 8 9
0
8 1 Repair walls and ceiling 4 8 12
1 2
0 1 Dummy 0 12 12
1 4
0 1 Dummy 0 12 12
2 6
1 1 Inst all new fume hood 1 12 13
4 6
1 1 Dummy 0 12 12
4
1 22 Inst all wall cabinet s 5 12 17
1 8 /3
6 1 Inst all 1 base cabinet s 1 13 14
8
1 20 Dummy 0 14 14
8
1 22 Inst all 2/3 base cabinet s 2 14 16
20 22 Inst all chemical sink 1 14 15
22 24 Finish plumbing and elect rical 2 17 19
24 26 Dummy 0 20 20
24 28 Paint cabinet s 6 20 26
26 28 Paint walls and ceiling 3 20 23
28 30 Lay vinyl floor 1 26 27
Nabil Dmaidi 90
Forward Pass Comput at ions - Remodeling Chemical Laborat ory
i j Act ivit y Descript ion T (Days) ESD EFD LSD LFD
2 4 St rip room 3 0 3 1 4
2 12 Obt ain fume hood 10 0 10 4 14
2 14 Obt ain cabinet 10 0 10 3 13
2 20 Obt ain chemical sink 10 0 10 7 17
2 24 Paint er availabilit y 20 0 20 0 20
2 28 Obt ain vinyl floor covering 5 0 5 21 26
4 6 Rough-in plumbing and elect rical 5 3 8 4 9
4 8 Replace exist ing fume duct 3 3 6 6 9
6 8 Dummy 0 8 8 9 9
6 10 Repair floor 1 8 9 12 13
8 10 Repair walls and ceiling 4 8 12 9 13
10 12 Dummy 0 12 12 14 14
10 14 Dummy 0 12 12 13 13
12 16 Inst all new fume hood 1 12 13 14 15
14 16 Dummy 0 12 12 15 15
14 22 Inst all wall cabinet s 5 12 17 13 18
16 18 /3
Inst all 1 base cabinet s 1 13 14 15 16
18 20 Dummy 0 14 14 17 17
18 22 Inst all 2/3 base cabinet s 2 14 16 16 18
20 22 Inst all chemical sink 1 14 15 17 18
22 24 Finish plumbing and elect rical 2 17 19 18 20
24 26 Dummy 0 20 20 23 23
24 28 Paint cabinet s 6 20 26 20 26
26 28 Paint walls and ceiling 3 20 23 23 26
28 30 Lay vinyl floor 1 26 27 26 27
Nabil Dmaidi 91
1. Total Float
Total float may be defined as that time span
in which the completion of an activity may
occur and not delay the termination of the
project.
TFij = LFDij - EFDij
= LSDij - ESDij
Nabil Dmaidi 92
2. Free Float
Free float may be defined as the time span
in which the completion of an activity may
occur and not delay the finish of the project
nor delay the start of any following activity.
FFij = ESDjk - EFDij
Nabil Dmaidi 93
3. Interfering Float
That part of the total float which remains after free
float has been deducted is the interfering float.
It may be defined as: the time span in which the
completion of an activity may occur and not delay
the termination of the project but within which
completion will delay the start of some other
following activity.
INTFij = TFij - FFij
Nabil Dmaidi 94
4. Independent Float
The fourth float, independent float, is the amount
of scheduling leeway of an activity that is
independent of the early starts and late finishes of
any other activity. It may be formally defined as:
The time span in which the completion of an
activity may occur and not delay the termination
of the project, not delay the start of any following
activity, and not be delayed by any preceding
activity.
Nabil Dmaidi 95
Forward Pass Comput at ions - Remodeling Chemical Laborat ory
i j Act ivit y Descript ion T (Days) ESD EFD LSD LFD TF FF INTF INDF
2 4 St rip room 3 0 3 1 4 1 0 1 -
2 12 Obt ain fume hood 10 0 10 4 14 4 2 2 2
2 14 Obt ain cabinet 10 0 10 3 13 3 2 1 2
2 20 Obt ain chemical sink 10 0 10 7 17 7 4 3 4
2 24 Paint er availabilit y 20 0 20 0 20 0 - - -
2 28 Obt ain vinyl floor covering 5 0 5 21 26 21 21 0 21
4 6 Rough-in plumbing and elect rical 5 3 8 4 9 1 0 1 -
4 8 Replace exist ing fume duct 3 3 6 6 9 3 2 1 1
6 8 Dummy 0 8 8 9 9 1 0 1 -
6 10 Repair floor 1 8 9 12 13 4 3 1 2
8 10 Repair walls and ceiling 4 8 12 9 13 1 0 1 -
10 12 Dummy 0 12 12 14 14 2 0 2 -
10 14 Dummy 0 12 12 13 13 1 0 1 -
12 16 Inst all new fume hood 1 12 13 14 15 2 0 2 -
14 16 Dummy 0 12 12 15 15 3 1 2 0
14 22 Inst all wall cabinet s 5 12 17 13 18 1 0 1 -
16 18 Inst all 1 base cabinet s
/3 1 13 14 15 16 2 0 2 -
18 20 Dummy 0 14 14 17 17 3 0 3 -
18 22 Inst all 2/3 base cabinet s 2 14 16 16 18 2 1 1 0
20 22 Inst all chemical sink 1 14 15 17 18 3 2 1 0
22 24 Finish plumbing and elect rical 2 17 19 18 20 1 1 0 0
24 26 Dummy 0 20 20 23 23 3 0 3 -
24 28 Paint cabinet s 6 20 26 20 26 0 - - -
26 28 Paint walls and ceiling 3 20 23 23 26 3 3 0 3
28 30 Lay vinyl floor 1 26 27 26 27 0 - - -
Nabil Dmaidi 96
Critical Path Computations on
the Network
Nabil Dmaidi 97
The Two Event Approach
Early Start Event
In the forward pass, the maximum of the EFD
values for all activities merging at a node is
taken as ESD value for all the activities that
burst from the same node.
TEj = MaxI (TEi +Tij)
Nabil Dmaidi 98
For all activities entering node j, TEj
is taken as the greatest sum of all
activities merge to the node
Nabil Dmaidi 99
Late Finish Event
– In the backward computations, the
minimum of LSD valves is taken as the
latest finish time for all activities that
enter the node.
TLj = MinI (TLi +Tij)
Nabil Dmaidi 100
by the last activity, the TL for the
Start
next earlier node is taken as the
minimum value of the late time event
minus activity duration.
Nabil Dmaidi 101
Nabil Dmaidi 102
Float Calculations From Event Times
Total Float
Tfij = TLj - TEi - Tij
Example
TF2-20 = TL20 - TE2 - T2-20
= 17 - 0 - 10 = 7
Nabil Dmaidi 103
Free Float
FFij = TEj - TEi - Tij
Example
FF2-20 = TE20 - TE2 - T2-20
= 14 - 0 - 10 = 4
Nabil Dmaidi 104
Scheduling Computations
for
Precedence Networks
Nabil Dmaidi 105
Tabular Format (Precedence Diagram)
Can be carried out on the tabular form
without reference to the diagram.
Advantage: the time required to construct
the diagram is eliminated.
Nabil Dmaidi 106
Link Lag
A link lag is the difference between the
early start date of an activity and the early
finish date of the preceding activity
LAGij = ESDj - EFDi
Nabil Dmaidi 107
Determining log
Examples:
LAG 5-10 = ESD 10 - EFD 5 = 4 - 4 = 0
LAG 15-25 = ESD 25 - EFD 15 = 12 - 7 = 5
LAG 20-25 = ESD 25 - EFD 20 = 12 - 6 = 6
Nabil Dmaidi 108
Determining the Free-Float
Free Float is the minimum of the log of the
link that follows an activity.
Look at the “Pre. column” to find the same
number value of EF for terminal activity
“not following act.”
FFi = Minj - LAG ij
FF 35 = LFD 35 - EFD 35 = 20 - 20 = 0
Nabil Dmaidi 109
Determining the Total Float “Backward”
TF i = Min (log ij + TF j )
Take TF of the terminal activity = 0
or TF 35 = LFD 35 - EFD 35 = 20 - 20 = 0
Nabil Dmaidi 110
Determining the Total Float “Backward” (cont.)
TF 30 = Min (log 30-35 + TF 35 ) =
Min ( 7 + 0 ) = 7
No other link
{ } { }
TF 20 = Min LAG20-25 + TF 25 = Min 6+0 = 6
LAG20-30 + TF 30 1+7
Nabil Dmaidi 111
INTF Float
INTF = TF - FF
Nabil Dmaidi 112
If the free float is zero - no INDF
INDF j = FF j - Max _ I ( TF I - LAGIJ )
INDF 20 = FF 20 - Max ( TF 5 - LAG5-20 )
= 1- (0 -0 )=1
{
INDF 30 = FF 30 – Max TF 15 - LAG15-30
TF 20 - LAG20-30 }
{ }
= 7- 5-0 =2
6-1
Nabil Dmaidi 113
Float Determination -
Sample Precedence Network
Nabil Dmaidi 114
Late Date Determination -
Sample Precedence Network
Nabil Dmaidi 115
Lag Determination -
Sample Precedence Network
Nabil Dmaidi 116
Forward Pass Calculations
Early start / Early Finish
8
EF = ES + D
3
4 15
11 17
6 7
6 14
0 4 11
18 31 45
1 2 4 8 9 10
4 7 7 7 14
8
5
4 10
Nabil Dmaidi 117
Backward Pass Calculations
Late start / Late Finish
11 LS = LF - D
3
4 15
11 17
6 7
6 14
0 4 11 24 31 45
1 2 4 8 9 10
4 7 7 7 14
24
5
4 10
Nabil Dmaidi 118
11 The Critical activities
Total Float= LF – ES – D
8
3
4 15
11 17
11 17
6 7
6 14
0 4 11
24 31 45
0 4 11
18 31 45
1 2 4 8 9 10
4 7 7 7 14
24
8
5
4 10
Nabil Dmaidi 119
11 The critical Path
8
3
4 15
11 17
11 17
6 7
6 14
0 4 11
24 31 45
0 4 11
18 31 45
1 2 4 8 9 10
4 7 7 7 14
24
8
5
4 10
Nabil Dmaidi 120
Exercise
Draw a network for the following activities.
Activity Duration IPAs
A 2 --
B 2 A
C 4 A
D 1 C
E 4 B,C
F 2 B
G 1 D
H 4 F,E
I 2 F
J 4 G,H
K 4 I,H
L 1 K,J
Nabil Dmaidi 121
The Arrow Network will be:
A B 3 F I
1 2 9 10
2 2 2 2
K
C 4 4
E H L
4 6 7 11 12 13
4 4 1
1 J
D 4
G 8
5
1
Nabil Dmaidi 122
Forward Pass calculations (ES, EF)
0 2 4 6 14
A B 3 F I
1 2 9 10
2 2 2 2
K
C 4 6 14 4 18 19
6 10
E H L
4 6 7 11 12 13
4 4 1
1 J
D 7 4
14
G 8
5
1
Nabil Dmaidi 123
backward Pass calculations (LS, LF)
0 2 6 10 14
A B 3 F I
1 2 9 10
2 2 2 2
K
C 4 6 14 4 18 19
6 10
E H L
4 6 7 11 12 13
4 4 1
1 J
D 13 4
14
G 8
5
1
Nabil Dmaidi 124
Specify the Critical Path
0 2 6 10 14
0 2 4 6 14
A B 3 F I
1 2 9 10
2 2 2 2
6 6 10 14 K 18 19
C 4 6 14 4 18 19
6 10
E H L
4 6 7 11 12 13
4 4 1
13 14 J
1 4
D 7 14
G 8
5
1
Nabil Dmaidi 125
0 2 6 10 14
0 2 4 6 14
A B 3 F I
1 2 9 10
2 2 2 2
6 6 10 14 K 18 19
C 4 6 14 4 18 19
6 10
E H L
4 6 7 11 12 13
4 4 1
13 14 J
1 4
D 7 14
G 8
5
1
Nabil Dmaidi 126
Table of activities
EF = ES + D
Activity Duration IPAs ES EF
A 2 -- 0 2
B 2 A 2 4
C 4 A 2 6
D 1 C 6 7
E 4 B,C 6 10
F 2 B 4 6
G 1 D 7 8
H 4 F,E 10 14
I 2 F 6 8
J 4 G,H 14 18
K 4 I,H 14 18
L 1 K,J 18 19
Nabil Dmaidi 127
Table of activities
LS = LF - D
Activity Duration IPAs ES EF LS LF
A 2 -- 0 2 0 2
B 2 A 2 4 4 6
C 4 A 2 6 2 6
D 1 C 6 7 12 13
E 4 B,C 6 10 6 10
F 2 B 4 6 8 10
G 1 D 7 8 13 14
H 4 F,E 10 14 10 14
I 2 F 6 8 12 14
J 4 G,H 14 18 14 18
K 4 I,H 14 18 14 18
L 1 K,J 18 19 18 19
Nabil Dmaidi 128
Total Float (TF): The amount of time an activity can be delayed
without delaying the overall project completion.
TF = LF – ES – D
= LF – EF
= LS - ES
Activity Duration IPAs ES EF LS LF TF
A 2 -- 0 2 0 2 0
B 2 A 2 4 4 6 2
C 4 A 2 6 2 6 0
D 1 C 6 7 12 13 6
E 4 B,C 6 10 6 10 0
F 2 B 4 6 8 10 4
G 1 D 7 8 13 14 6
H 4 F,E 10 14 10 14 0
I 2 F 6 8 12 14 6
J 4 G,H 14 18 14 18 0
K 4 I,H 14 18 14 18 0
L 1 K,J 18 19 18 19 0
Nabil Dmaidi 129
Total Float (TF): The amount of time an activity can be delayed
without delaying the overall project completion.
TF = LF – ES – D
= LF – EF
= LS - ES
Activity Duration IPAs ES EF LS LF TF
A 2 -- 0 2 0 2 0
B 2 A 2 4 4 6 2
C 4 A 2 6 2 6 0
D 1 C 6 7 12 13 6
E 4 B,C 6 10 6 10 0
F 2 B 4 6 8 10 4
G 1 D 7 8 13 14 6
H 4 F,E 10 14 10 14 0
I 2 F 6 8 12 14 6
J 4 G,H 14 18 14 18 0
K 4 I,H 14 18 14 18 0
L 1 K,J 18 19 18 19 0
Nabil Dmaidi 130
Bar / Gantt chart Early Start / Finish
Activity
EF = ES + D
A
B
C
D
E
F
G
H
I
J
K
L
2 4 6 8 10 12 14 16 18 20
Time
Nabil Dmaidi 131
Bar / Gantt Chart Late Start / Finish
Activity
LS = LF - D
A
B
C
D
E
F
G
H
I
J
K
L
2 4 6 8 10 12 14 16 18 20
Time
Nabil Dmaidi 132
Bar / Gantt of the previous network
A
B
C
D
E
F
G
H
I
J
K
L
2 4 6 8 10 12 14 16 18 20
Nabil Dmaidi 133
Bar / Gantt chart Early Start / Finish
Activity
EF = ES + D
A
B
C
D
E
F
G
H
I
J
K
L
2 4 6 8 10 12 14 16 18 20
Time
Nabil Dmaidi 134
Bar / Gantt Chart Late Start / Finish
Activity
LS = LF - D
A
B
C
D
E
F
G
H
I
J
K
L
2 4 6 8 10 12 14 16 18 20
Time
Nabil Dmaidi 135
Bar / Gantt of the previous network
A
B
C
D
E
F
G
H
I
J
K
L
2 4 6 8 10 12 14 16 18 20
Nabil Dmaidi 136
2) PDM Precedence Diagramming Method
Activity On Node (AON) Method
PDM is the primary method in use today.
Used by most of the computer software.
MS Project
Primavera
Nabil Dmaidi 137
PDM Precedence Diagramming Method
The PDM depicts activities as NODES in
the network linked with logic lines.
The node representing the activity.
Arrow representing relationship /
dependency
PDM should be red left to right
Nabil Dmaidi 138
PDM Precedence Diagramming Method
PDM looks like the following:
Activity A Activity B
• The shape of the node could be any shape
Nabil Dmaidi 139
PDM vs. ADM
ADM PDM
A C
1 2 3 A C
=
B D
4 5 6 B D
Nabil Dmaidi 140
PDM vs. ADM
ADM PDM
B
3
B
A
1 2
C
4 = A C
D
5 D
Nabil Dmaidi 141
Exercise
Draw a PDM for the following activities.
Activity Activity
Label Description IPAs
A Lay out --
B Excavation A
C place formwork B
E purchase steel --
F bend steel E
G place steel C,F
H order concrete --
D place concrete G,H
Nabil Dmaidi 142
The PDM will be:
H
A B C D
E F G
Nabil Dmaidi 143
Clean surface Spread grout
SS
Set tile Clean floor area
Nabil Dmaidi 144
Precedence Network Calculations
the basic information that should be
calculated in the precedence network are:
1) Early activity start (ES)
2) Early activity finish (EF)
3) Late activity start (LS)
4) Late activity finish (LF)
5) Free Float (FF)
6) Total Float (TF)
Nabil Dmaidi 145
Precedence Network Calculations
The previously mentioned information can
be illustrated in the activity nod in the
network:
Activity description
ES Duration LS
EF FF TF LF
Nabil Dmaidi 146
Precedence Network Calculations
ES: the earliest time that an activity can start as
determined by the latest of the early finish times of all
immediately preceding activities.
EF: the earliest time that an activity can finish, determined
by EF = ES + D
LS : the latest time that an activity can start without
delaying the project completion.
LS = LF – D.
LF : the latest time that an activity can be finished without
delaying the project completion, as determined by the
earliest of the late starts of the immediately succeeding
activities.
Nabil Dmaidi 147
Precedence Network Calculations
FF: the amount of time that an activity can be
delayed before it impacts the start of any
succeeding activities.
TF: the amount of time that an activity can be
delayed before it impacts the project completion.
Lag: the amount of time that exists between the
EF of an activity and the ES of a specified
succeeding activity.
LAGAB = ESB - EFA
Nabil Dmaidi 148
Precedence Network Calculations
Reminder: The manual calculations
assumes that the relationships between
activities are Finish to Start (FS) Type.
Nabil Dmaidi 149
Precedence Network Calculations
1) Forward pass calculations 4) Backward pass calculations
5) Calculate total Float (TF = LS – ES OR LF – EF)
A 0
B 0
D 0
F 0
H
1 1 1 2 9 2 11 5 11 16 4 16 20 1 20
2 0 0 2 11 0 0 11 16 0 0 16 20 0 0 20 21 0 0 21
4 5 3
0
C E G
0 0
2 5 5 7 4 10 11 6 14
7 0 3 10 11 0 3 14 17 3 3 20
2) Calculate the Lag ( LAGAB = ESB - EFA
ES Dur. LS
min. LAG
3) Calculate the Free Float (FF) FF =Nabil Dmaidi EF FF TF LF
150
Precedence Network Calculations
6) Determine the Critical Path
A 0
B 0
D 0
F 0
H
1 1 1 2 9 2 11 5 11 16 4 16 20 1 20
2 0 0 2 11 0 0 11 16 0 0 16 20 0 0 20 21 0 0 21
4 5 3
0
C E G
0 0
2 5 5 7 4 10 11 6 14
7 0 3 10 11 0 3 14 17 3 3 20
The critical path passes through the critical activities where TF = 0 ES Dur. LS
Nabil Dmaidi EF FF TF LF
151
Bar / Gantt chart Early Start / Finish
Activity
EF = ES + D
A
B
C
D
E
F
G
H
2 4 6 8 10 12 14 16 18 20
Time
Nabil Dmaidi 152
Bar / Gantt chart Late Start / Finish
Activity
LS = LF - D
A
B
C
D
E
F
G
H
2 4 6 8 10 12 14 16 18 20
Time
Nabil Dmaidi 153
Bar / Gantt chart
Activity
A
B
C
D
E
F
G
H
2 4 6 8 10 12 14 16 18 20
Time
Nabil Dmaidi 154
Exercise
1) Forward pass calculations 4) Backward pass calculations
electrical Water
conduit 8 proofing
7 2 15 25 3 25
0
9 8 8 17 28 0 0 28 0
0
Block work plumbing Inspection plaster Floor tile
0 0 0
1 6 1 7 4 7 11 6 11 17 8 17 28 1 28
7 0 0 7 11 0 0 11 17 0 0 17 25 0 0 25 29 0 0 29
0 sub-frames
9
7 1 16
8 9 9 17
ES Dur. LS
2) Calculate the Lag ( LAGAB = ESB - EFA
EF FF TF LF Nabil Dmaidi 155
3) Calculate the Free Float (FF) FF = min. LAG
6) Determine the Critical Path
5) Calculate total Float (TF = LS – ES OR LF – EF)
electrical Water
conduit 8 proofing
7 2 15 25 3 25
0
9 0 8 17 28 0 0 28 0
0
Block work plumbing Inspection plaster Floor tile
0 0 0
1 6 1 7 4 7 11 6 11 17 8 17 28 1 28
7 0 0 7 11 0 0 11 17 0 0 17 25 0 0 25 29 0 0 29
0 sub-frames
9
7 1 16
8 0 9 17
ES Dur. LS
EF FF TF LF Nabil Dmaidi 156
Activities Duration
Activity duration: is the estimated time
required to complete an activity.
Activity duration mainly calculated based
on the quantities take off.
And labor or machines productivity rates.
Nabil Dmaidi 157
Activities Duration
Durations could be estimated by experience.
( previous similar jobs)
If experience not available, others
experience could be utilized.
If not, handbooks of productivity rates are
available provide the required information.
Nabil Dmaidi 158
Activities Duration
Activity duration can be calculated as
follows:
quantity of the work
= crew hours
qty / crew hour
qty / crew hour is the productivity rate.
Time unit is hours could be changed to working days.
Nabil Dmaidi 159
Activities Duration
Example: assume that you have a floor tile area of 600 M2 , and the
productivity rate of a tile mason and one helper is 1.5 M2 / hour.
By applying the previous equation:
600 M2
= 400 hours
1.5 M2 / h
If the time unit is working day ( 8 hours) :
400 hours
= 50 days
8 hours
Nabil Dmaidi 160
Time & Cost Theoretical
Relationship
Minimum Duration
Cost
A B
Duration
Nabil Dmaidi 161
Some Factors that affects
Duration
1) Weather.
2) Availability, quality, and training of operatives.
3) Familiarity with the work.
4) Quality of workmanship specified.
5) Quality of management/supervision.
6) Size and completion date of project.
7) Length and incidence of holidays.
8) Repetitiveness of the work.
9) Physical constraints of the site. Such as access,
size, storage space and etc.
Nabil Dmaidi 162
1) Weather
Allowance for weather is important for
activities duration.
Its particularly critical for excavation and
earth moving activities.
Tow approaches to tackle delay due to
weather conditions:
Nabil Dmaidi 163
1) Weather Cont.
1) First approach: each activity has an added
allowance of possible delays due to weather.
Fixed percentage is added to each activity for
this purpose.
But, it produces difficulties for activities with
long duration, if these activities are not sensitive
to weather.
Nabil Dmaidi 164
1) Weather Cont.
2) Second approach: adding a single
allowance at the end of the project.
This method works best if the work
activities have more or less the same
sensitivity to weather. And the weather does
not vary significantly from period to period.
Nabil Dmaidi 165
1) Weather Cont.
A delay activity could be added separately
to the network represents the weather delay.
Nabil Dmaidi 166
E
10 6 16
16 6 6 22
B F I
6 4 12 11 2 17 13 3 19
10 0 6 16 13 0 6 19 16 6 6 22
A C G K
1 5 1 6 5 6 11 3 11 22 2 22
6 0 0 6 11 0 0 11 14 0 0 14 24 0 0 24
D J
6 2 12 14 14
8
8 0 6 14 22 0 0 22
H
ES Dur. LS
8 6 16
EF FF TF LF
8 Dmaidi
14 Nabil8 22 167
E
10 4 16
14 6 6 20
B F I
6 4 12 9 2 15 11 3 17
10 0 6 16 11 0 6 17 14 6 6 20
A C G K
1 5 1 6 3 6 9 3 9 20 2 20
6 0 0 6 9 0 0 9 12 0 0 12 22 0 0 22
D J
6 2 10 12 8 12
8 0 4 12 20 0 0 20
H
ES Dur. LS
8 7 13
EF FF TF LF
5 Dmaidi
15 Nabil5 20 168
E
6
B F I
4 2 3
A C G K
1 5 5 3 2
D J
2 8
H
ES Dur. LS
6
EF FF TF LF
Nabil Dmaidi 169
E
4
B F I
4 2 3
A C G K
1 5 3 3 2
D J
2 8
H
ES Dur. LS
7
EF FF TF LF
Nabil Dmaidi 170
Resources Allocation & Leveling
A time only network assumes that any other
needed resources are available at any time.
E.g. if the excavation activity requires three
large mechanical excavators, A time only
network assumes that these excavators are
available on site at the required time. This
seems to be uneconomic situation.
Nabil Dmaidi 171
Resources Allocation & Leveling
A B D F H
1 1 1 2 9 2 11 5 11 16 4 16 20 1 20
2 0 0 2 11 0 0 11 16 0 0 16 20 0 0 20 21 0 0 21
8H 9H 5H 8H 4H
C E G
2 5 5 7 4 10 11 6 14
7 0 3 10 11 0 3 14 17 3 3 20
Activity 7H 4H 2H
desc.
ES Dur. LS
EF FF TF LF
Resources
Nabil Dmaidi 172
Sort
Sort : the process of arranging activities in
a list to certain specific order.
Nabil Dmaidi 173
Priorities & Sorts
The activities making up the network must
be listed in order of their priority of
resources allocation.
The network shows the logical sequence of
activities. (predecessor and successor).
The listing of activities must therefore
reflects the dependency of some activities .
Nabil Dmaidi 174
Activities Sort
Activity Duration ES TF Resource unit
A 1 1 0 8H
B 9 2 0 9H
C 5 2 3 7H
D 5 11 0 5H
E 4 7 3 4H
F 4 16 0 8H
G 6 11 3 2H
H 1 20 0 4H
Activity sort reflects the logic sequence of the network.
Nabil Dmaidi 175
Major Sort
Activity Duration ES TF Resource unit
A 1 1 0 8H
B 9 2 0 9H
C 5 2 3 7H
E 4 7 3 4H
G 6 11 3 2H
D 5 11 0 5H
F 4 16 0 8H
H 1 20 0 4H
Activity sort with ES time as Major sort
Nabil Dmaidi 176
Major & Minor Sorts
Activity Duration ES TF Resource unit
A 1 1 0 8H
B 9 2 0 9H
C 5 2 3 7H
E 4 7 3 4H
D 5 11 0 5H
G 6 11 3 2H
F 4 16 0 8H
H 1 20 0 4H
Activity sort with ES time as Major sort & TF as Minor Sort
Nabil Dmaidi 177
Allocated resources
8H
A
9H 9H 9H 9H 9H 9H 9H 9H 9H
B
7H 7H 7H 7H 7H
Activity
C
4H 4H 4H 4H
E
5H 5H 5H 5H 5H
D
2H 2H 2H 2H 2H 2H
G
8H 8H 8H 8H
F
4H
H
2 4 6 8 10 12 14 16 18 20
Time
Nabil Dmaidi 178
Time
2 4 6 8 10 12 14 16 18 20
8H
A
9H 9H 9H 9H 9H 9H 9H 9H 9H
B
7H 7H 7H 7H 7H
C
4H 4H 4H 4H
Activity
E
5H 5H 5H 5H 5H
D
2H 2H 2H 2H 2H 2H
G
8H 8H 8H 8H
F
4H
H
Total Labor 8 16 16 16 16 16 13 13 13 13 7 7 7 7 7 10 8 8 8 4
Early start resources aggregation
Nabil Dmaidi 179
Resource Aggregation
Resources aggregation: is a summation of
the resources that are used to carry out the
program on a time period basis. For
example, day to day , or week to week.
Nabil Dmaidi 180
Total Labor 8 16 16 16 16 16 13 13 13 13 7 7 7 7 7 10 8 8 8 4
16
Labor
14
12
10
8
6
4
2
2 4 6 8 10 12 14 16 18 20
Nabil Dmaidi Time
181
Early start resources aggregation diagram (Histogram)
Late start
Another histogram can be obtained if Late start
considered. Shows different resources demand.
And many histograms can be obtained
considering a different time in the network.
Each histogram shows different resources
demand.
Nabil Dmaidi 182
Late start Sorts
Activity Duration LS TF Resource unit
A 1 1 0 8H
B 9 2 0 9H
C 5 5 3 7H
E 4 10 3 4H
D 5 11 0 5H
G 6 14 3 2H
F 4 16 0 8H
H 1 20 0 4H
Activity sort with LS time as Major sort & TF as Minor Sort
Nabil Dmaidi 183
Time
2 4 6 8 10 12 14 16 18 20
8H
A
9H 9H 9H 9H 9H 9H 9H 9H 9H
B
7H 7H 7H 7H 7H
C
4H 4H 4H 4H
Activity
E
5H 5H 5H 5H 5H
D
2H 2H 2H 2H 2H 2H
G
8H 8H 8H 8H
F
4H
H
Total Labor 8 9 9 9 16 16 16 16 16 13 9 9 9 7 7 10 10 10 10 4
resources
Late startNabil Dmaidi aggregation 184
Total Labor 8 9 9 9 16 16 16 16 16 13 9 9 9 7 7 10 10 10 10 4
16
Labor
14
12
10
8
6
4
2
2 4 6 8 10 12 14 16 18 20
Nabil Dmaidi
Late start resources aggregation diagram (Histogram) 185
Time
Total Labor 8 9 9 9 16 16 16 16 16 13 9 9 9 7 7 10 10 10 10 4
16
Labor
14
12
10
8
6
4
2
2 4 6 8 10 12 14 16 18 20
Time
186
Nabil Dmaidi aggregation diagram (Histogram)
Early start vs Late start resources
Total Labor 8 9 9 9 16 16 16 16 16 13 9 9 9 7 7 10 10 10 10 4
16
Labor
14
12
10
8
6
4
2
2 4 6 8 10 12 14 16 18 20
Nabil Dmaidi
Time
187
Early start vs Late start resources aggregation diagram (Histogram)
E
10 6 16
16 6 6 22
B F I
6 4 12 11 2 17 13 3 19
10 0 6 16 13 0 6 19 16 6 6 22
A C G K
1 5 1 6 5 6 11 3 11 22 2 22
6 0 0 6 11 0 0 11 14 0 0 14 24 0 0 24
D J
6 2 12 14 14
8
8 0 6 14 22 0 0 22
H
ES Dur. LS
8 6 16
EF FF TF LF
8 Dmaidi
14 Nabil8 22 188
Activities Sort
Activity Duration ES TF Resource unit
A 5 1 0 8H
C 5 6 0 2H
D 2 6 6 4H
B 4 6 6 9H
H 6 8 8 5H
E 6 10 6 5H
G 3 11 0 2H
F 2 11 6 8H
I 3 13 6 5H
J 8 14 0 2H
K 2 22 0 6H
Activity sort with ES time as Major sort & TF and duration as Minor Sorts
Nabil Dmaidi 189
Time
2 4 6 8 10 12 14 16 18 20 22 24
A 8H 8H 8H 8H 8H
C 2H 2H 2H 2H 2H
D 4H 4H
B 9H 9H 9H
9H 9H 9H 9H
H 5H 5H 5H 5H 5H 5H
E 5H 5H 5H 5H 5H 5H
G 2H 2H 2H
F 8H 8H
I 5H 5H 5H
J 2H 2H 2H 2H 2H 2H 2H 2H
K 6H 6H
Total
Labor
8 8 8 8 8 15 15 16 16 12 20 20 17 12 12 2 2 2 2 2 2 6 6
Nabil Dmaidi 190
Early start resources aggregation
Total
Labor
8 8 8 8 8 15 15 16 16 12 20 20 17 12 12 2 2 2 2 2 2 6 6
20
18
16
Labor
14
12
10
8
6
4
2
2 4 6 8 10 12 14 16 18 20 22 24
Nabil Dmaidi 191
Time Early start resources aggregation diagram
Activities Sort
Activity Duration LS TF Resource unit
A 5 1 0 8H
C 5 6 0 2H
D 2 12 6 4H
B 4 12 6 9H
E 6 16 6 5H
H 6 16 8 5H
G 3 11 0 2H
F 2 17 6 8H
I 3 19 6 5H
J 8 14 0 2H
K 2 22 0 6H
Activity sort with LS time as Major sort & TF and duration as Minor Sorts
Nabil Dmaidi 192
Time
2 4 6 8 10 12 14 16 18 20 22 24
A 8H 8H 8H 8H 8H
C 2H 2H 2H 2H 2H
D 4H 4H
B 9H 9H 9H 9H
E 5H 5H 5H 5H 5H 5H
H 5H 5H 5H 5H 5H 5H
G 2H 2H 2H
F 8H 8H
I 5H 5H 5H
J 2H 2H 2H 2H 2H 2H 2H 2H
K 6H 6H
Total
Labor
8 8 8 8 8 2 2 2 2 2 2 15 15 11 11 12 20 20 17 17 17 6 6
Nabil Dmaidi 193
Late start resources aggregation
Total
8 8 8 8 8 2 2 2 2 2 2 15 15 11 11 12 20 20 17 17 17 6 6
Labor
20
18
16
Labor
14
12
10
8
6
4
2
2 4 6 8 10 12 14 16 18 20 22 24
Nabil Dmaidi 194
Time Late start resources aggregation diagram
Early start
20
18
Labor
16
14
12
10
8
6
4
2
2 4 6 8 10 12 14 16 18 20 22 24
Time
20
18 Late start
Labor
16
14
12
10
8
6
4
2
2 4 6 8 10 12 14 16 18 20 22 24
Nabil Dmaidi 195
Time
Total
Labor
8 8 8 8 8 15 15 16 16 12 20 20 17 12 12 2 2 2 2 2 2 6 6
20
18
16
Labor
14
12
10
8
6
4
2
2 4 6 8 10 12 14 16 18 20 22 24
Nabil Dmaidi 196
Time Early/Late start resources aggregation diagra
Smoothing/Leveling
Let us program activity F to start by its late start
day which is day 17
And activity I to start by day 14.
The resulting resources aggregation histogram will
be as follows:
Nabil Dmaidi 197
Time
2 4 6 8 10 12 14 16 18 20 22 24
A 8H 8H 8H 8H 8H
C 2H 2H 2H 2H 2H
D 4H 4H
B 9H 9H 9H
9H 9H 9H 9H
H 5H 5H 5H 5H 5H 5H
E 5H 5H 5H 5H 5H 5H
G 2H 2H 2H
F 8H 8H
I 5H 5H 5H
J 2H 2H 2H 2H 2H 2H 2H 2H
K 6H 6H
Total
Labor
8 8 8 8 8 15 15 16 16 12 12 12 12 12 12 7 10 10 2 2 2 6 6
Nabil Dmaidi 198
Early start resources aggregation
Total
Labor 8 8 8 8 8 15 15 16 16 12 12 12 12 12 12 7 10 10 2 2 2 6 6
20
18
16
Labor
14
12
10
8
6
4
2
2 4 6 8 10 12 14 16 18 20 22 24
Nabil Dmaidi 199
Time
Smoothing/Leveling
Let us program activity H to start by its late
start time.
So its resources demand starts with its Late
start date.
The resulting resource aggregation and
histogram will be as follows:
Nabil Dmaidi 200
Time
2 4 6 8 10 12 14 16 18 20 22 24
A 8H 8H 8H 8H 8H
C 2H 2H 2H 2H 2H
D 4H 4H
B 9H 9H 9H
9H 9H 9H 9H
H 5H 5H 5H 5H 5H 5H
E 5H 5H 5H 5H 5H 5H
G 2H 2H 2H
F 8H 8H
I 5H 5H 5H
J 2H 2H 2H 2H 2H 2H 2H 2H
K 6H 6H
Total
Labor
8 8 8 8 8 15 15 16 16 7 15 15 12 7 7 7 7 7 7 7 7 6 6
Nabil Dmaidi 201
resources aggregation
Total
Labor
8 8 8 8 8 15 15 16 16 7 15 15 12 7 7 7 7 7 7 7 7 6 6
20
18
16
Labor
14
12
10
8
6
4
2
2 4 6 8 10 12 14 16 18 20 22 24
Nabil Dmaidi 202
Time
Smoothing/Leveling
In case activity D is splitable activity. It could be
interrupted to be carried out in tow parts.
Let us program activity B to start by 7th day .
And activity H to starts by its Late start date.
And activity E to start by day 14.
The resulting resource aggregation and histogram will be
as follows:
Nabil Dmaidi 203
Time
2 4 6 8 10 12 14 16 18 20 22 24
A 8H 8H 8H 8H 8H
C 2H 2H 2H 2H 2H
D 4H 4H
B 9H 9H 9H 9H
H 5H 5H 5H 5H 5H 5H
E 5H 5H 5H 5H 5H 5H
G 2H 2H 2H
F 8H 8H
I 5H 5H 5H
J 2H 2H 2H 2H 2H 2H 2H 2H
K 6H 6H
Total
Labor
8 8 8 8 8 6 11 11 11 11 10 10 11 12 12 12 12 12 12 7 7 6 6
Nabil Dmaidi 204
Early start resources aggregation
Total
Labor 8 8 8 8 8 6 11 11 11 11 10 10 11 12 12 12 12 12 12 7 7 6
20
18
16
Labor
14
12
10
8
6
4
2
2 4 6 8 10 12 14 16 18 20 22 24
Nabil Dmaidi 205
Time
Early Start or Early Finish
There are many solutions between the limits of
Early Start and Early Finish.
The optimal solution is zero fluctuation histogram.
Which is hard to be achieved.
It is preferred to solve the problem toward the
Early start resources aggregation diagram.
WHY ?!
Nabil Dmaidi 206
Early Start or Early Finish
Because if there are labor availability
problems to be overcome, they will occur in
the early beginning of the project.
By other words, if the program based on the
Late Start date, it means that all the
activities are Critical, and any labor
problem will affect the project completion.
Nabil Dmaidi 207
When Resources are Limited
Resources Allocation
The previous method of resources aggregation has
been carried out within a fixed project duration.
The basic objective was to optimize the use of the
resources and to know the mount of resources
needed to carry out the job on time period basis.
And to maintain the network based duration.
Nabil Dmaidi 208
Allocation within resources
restraints
Another situation which you may face in practice
is the restricted resources availability.
Where you have to carry out the job with the
available resources only.
In this case the project duration may be prolonged
to suit the availability of the restricted resources.
Nabil Dmaidi 209
Resources Allocation
A B D F H
1 1 1 2 9 2 11 5 11 16 4 16 20 1 20
2 0 0 2 11 0 0 11 16 0 0 16 20 0 0 20 21 0 0 21
8H 9H 5H 8H 4H
C E G
2 5 5 7 4 10 11 6 14
7 0 3 10 11 0 3 14 17 3 3 20
Activity 7H 4H 2H
desc.
ES Dur. LS
EF FF TF LF
Resources
Nabil Dmaidi 210
Activity list
Activity Duration LS TF Resource unit
A 1 1 0 8H
B 9 2 0 9H
C 5 5 3 7H
E 4 10 3 4H
D 5 11 0 5H
G 6 14 3 2H
F 4 16 0 8H
H 1 20 0 4H
Activity sort with LS time as Major sort & TF as Minor Sort
Nabil Dmaidi 211
Solve the schedule
Assume that the available labors in the
company restricted to 10 helpers, and the
company decided to carry out the job
without resorting to hire more labor.
The resulting program will exceed the Early
finish date based on the network.
Nabil Dmaidi 212
Total Labor 8 16 16 16 16 16 13 13 13 13 7 7 7 7 7 10 8 8 8 4
16
Labor
14
12
10
8
6
4
2
2 4 6 8 10 12 14 16 18 20
Nabil Dmaidi Time
213
Early start resources aggregation diagram (Histogram)
Rules for scheduling activities with
limited resources
1) schedule activities to start as soon as their predecessors
have been completed.
2) if more than one activity using a specific limited resources
can be scheduled, priority is given to the activity with early
Late Start. ( LS as Major Sort)
3) if tow or more activities have the same Late start, give
priority to the activity with least Total Float. (TF as Minor
Sort)
4) if the activities have the same Total Float in the minor sort,
give the priority to the activity with the Largest Number of
Resources.
5) If the activities are tied in the number of resources, give
priority to the activity that has already started.
Nabil Dmaidi 214
Resources Allocation
A B D F H
1 1 1 2 9 2 11 5 11 16 4 16 20 1 20
2 0 0 2 11 0 0 11 16 0 0 16 20 0 0 20 21 0 0 21
8H 9H 5H 8H 4H
C E G
2 5 5 7 4 10 11 6 14
7 0 3 10 11 0 3 14 17 3 3 20
Activity 7H 4H 2H
desc.
ES Dur. LS
EF FF TF LF
Resources
Nabil Dmaidi 215
Time
2 4 6 8 10 12 14 16 18 20 22 24 26
A 8H
B 9H 9H 9H 9H 9H 9H 9H 9H 9H
7H 7H 7H 7H
C
Activity
4H 4H 4H 4H
E
5H 5H 5H 5H 5H
D
G 2H 2H 2H 2H 2H 2H
F 8H 8H 8H
H 4H
Total Labor 8 9 9 9 9 9 9 9 9 9 7 7 7 7 9 9 9 9 7 10 10 10 2 2 4
12
Labor
10
Limit
Labor
8
6
4
2
Time Dmaidi
Nabil 216
Resources aggregation diagram
Money and network schedules
Reminder, cost was one of the elements of
project constraints triangle ( COST, TIME
& QUALITY)
An effective management tries to minimize
and integrate the above mentioned
elements.
Nabil Dmaidi 217
Money and network schedules
CPM provides a mean for relating time and
money.
The application of resources to a project
(materials, manpower and machinery)
related to another resource which is
MONEY.
The value of the resources for each activity
represents a component of project cost.
Nabil Dmaidi 218
Hint
Construction costs includes:
1) Materials costs.
2) labor costs.
3) plant and equipment costs
4) overhead costs and profit.
Nabil Dmaidi 219
E
10 6 16
16 6 6 22
B F I
6 4 12 11 2 17 13 3 19
10 0 6 16 13 0 6 19 16 6 6 22
A C G K
1 5 1 6 5 6 11 3 11 22 2 22
6 0 0 6 11 0 0 11 14 0 0 14 24 0 0 24
D J
6 2 12 14 14
8
8 0 6 14 22 0 0 22
H
ES Dur. LS
8 6 16
EF FF TF LF
8 Dmaidi
14 Nabil8 22 220
Activities cost
Activity Duration ES TF cost ( $)
A 5 1 0 650
C 5 6 0 1300
D 2 6 6 400
B 4 6 6 1450
H 6 8 8 500
E 6 10 6 1100
G 3 11 0 600
F 2 11 6 350
I 3 13 6 1000
J 8 14 0 1300
K 2 22 0 200
Nabil Dmaidi 221
Time
2 4 6 8 10 12 14 16 18 20 22 24
A 200 100 200 100 50
C 150 100 200 200 150
D 200 200
B 100 9H 9H 9H
9H 250 300 100
H 50 100 150 200 50 50
E 200 200 100 150 100 150
G 200 200 200
F 150 100
I 200 100 100
J 100 100 150 200 100 100 150 100
K 100 100
Total
200 100 200 100 50 350 550 550 400 500 750 450 600 300 350 150 200 100 100 150 100 100 100
cost
Nabil Dmaidi 222
Total
200 100 200 100 50 350 550 550 400 500 750 450 600 300 350 150 200 100 100 150 100 100 100
cost
800
700
600
500
400
300
200
100
2 4 6 8 10 12 14 16 18 20 22 24
Time Dmaidi
Nabil 223
Cash Flow
It is quite significant to the contractor to
know the amount of money that would be
spent in each stage of the project.(
Expenditures)
And compare it to the amount of money that
would be received. (income)
Nabil Dmaidi 224
Overtrading
Overtrading: arises when the current
liabilities of a company exceed the current
assets, even though the business is solvent.
Nabil Dmaidi 225
Time
2 4 6 8 10 12 14 16 18 20 22 24
A 200 100 200 100 50
C 150 100 200 200 150
D 200 200
B 100 9H 9H 9H
9H 250 300 100
H 50 100 150 200 50 50
E 200 200 100 150 100 150
G 200 200 200
F 150 100
I 200 100 100
J 100 100 150 200 100 100 150 100
K 100 100
Total
200 100 200 100 50 350 550 550 400 500 750 450 600 300 350 150 200 100 100 150 100 100 100
cost
Nabil Dmaidi 226
Total
200 100 200 100 50 350 550 550 400 500 750 450 600 300 350 150 200 100 100 150 100 100 100
cost
Com. 200 300 500 600 650 1000 1550 2100 2500 30003750 4200 4800 5100 5450 5600 580059006000 6150 6250 63506450
cost
$
6400
6000
5600
5200
4800
4400
4000
3600
3200
2800
2400
2000
1600
1200
800
400
2 4 6 8 10 12 14 16 18 20 22 24
Com. cost = Cumulative Cost Time Dmaidi
Nabil
Cash Flow Diagram
227
Retainage Release
Expenditures
Revenues
Cumulative
Expenditure
s
& Revenues
Amount of
Negative
Cash Flow
Time (Months)
Nabil Dmaidi
Cash Flow Curve for revenue and expenditures 228
Cash Flow Analysis
Cash flow analysis consists of a detailed
examination of funds disbursement (expenditures)
and the receipt of revenue.
Cash flow shows if surplus fund available during
project, or if negative cash position will occur
during construction.
The cash position of contractor during project
whether positive or negative is important.
Nabil Dmaidi 229
Negative cash position
Negative cash position means that the
revenues obtained from a project
insufficient to meet the financial obligations
(expenditures) of the project.
In this case other fund from the company or
from outside sources must be used.
Nabil Dmaidi 230
Positive cash position
Positive cash position means that the revenues
obtained from a project exceed the financial
obligations (expenditures) of the project.
In this case surplus (extra) fund available with the
contractor.
And the contractor may invest this surplus funds
for short duration.
Nabil Dmaidi 231
Time-Cost Trade-Off
Some amount of knowledge brings more……
Nabil Dmaidi 232
Time-Cost Trade-Off
For the following discussions it is important
to remember:
Direct costs: Related to putting the facility
components in place. They represent the
resources used by an activity. (material,
labor and equipment).
Nabil Dmaidi 233
Time-Cost Trade-Off
Indirect job costs (job overhead): costs that could
not be attributed to a specific work item. (such as,
site offices, superintendents, security fence & etc)
These costs are generally incurred whether or not
productive work achieved.
Longer project duration will result in higher
indirect costs.
Nabil Dmaidi 234
Time-Cost Trade-Off
Operating Overhead costs (company
overhead): If the cost cannot be attributed to
any specific job, they are operating
overhead costs, costs of running business.
(head office costs, communications & etc).
These costs continue as long as the
company exists even one project is running.
Nabil Dmaidi 235
Logic of Time-Cost Trade-Off
Assumption: increasing or decreasing an
activity’s duration will lead to increased
direct costs for that activity.
Nabil Dmaidi 236
Direct
Costs
Direct costs
Project duration
Nabil direct
General relation ofDmaidi costs to project duration 237
Logic of Time-Cost Trade-Off
Assumption: decreasing a project’s
duration will lead to lower indirect costs.
Nabil Dmaidi 238
Indirect
Costs
indirect costs
Project duration
Nabil indirect costs to project duration
General relation ofDmaidi 239
Logic of Time-Cost Trade-Off
Assumption: A project’s duration can be
decreased by decreasing the duration of
one or more critical activities on the
critical path.
Nabil Dmaidi 240
Logic of Time-Cost Trade-Off
Assumption: Decreasing a project’s duration may
increase or decrease the total cost of a project
depending upon whether the additional direct
costs required to decrease the activity duration
are greater or less than indirect costs savings of
decreasing the project’s duration.
تقليل المدة لزمنية للمشروع يمكن ان يزيد او يقلل من التكلفة
الكلية للمشروع , وذلك اعتمادا على ما اذا كانت التكاليف
اإلضافية لتقليل مدة العمل أكبر و أقل من التوفير في التكاليف
.الغير مباشرة
Nabil Dmaidi 241
Total project costs
Project
Costs
Direct costs
indirect costs
Project duration
Nabil project costs to project duration
General relation ofDmaidi 242
Graph analysis
A project’s total costs combines direct costs and indirect
costs. Therefore, the curve of total costs versus duration
involves adding the cost amounts of direct and indirect
costs curves.
Remember, the direct costs curve has a negative slope
(direct costs increase as duration decrease) and indirect
costs curve has a positive slope (indirect costs decrease as
duration decreases).
So, the slope of the total costs curves at any point depends
whether the slope of direct costs curve less than that of
indirect cost curve.
Nabil Dmaidi 243
B G I
2 9 2 11 5 11 16 9 16
11 0 0 11 16 0 0 16 25 0 0 25
9H, 450 $ 5H, 250 $ 8H, 450 $
A D F J
1 1 1 2 9 8 11 8 17 25 1 25
2 0 0 2 11 0 6 17 19 0 6 25 26 0 0 26
8H, 200 $ 9H, 900 $ 5H, 1200 $ 4H, 1500 $
C E H
2 5 10 7 4 15 11 6 19
7 0 8 15 11 0 8 19 17 8 8 25
Activity 7H, 500 $ 4H, 400 $ 2H, 900 $
desc.
ES Dur. LS
EF FF TF LF
Resources Nabil Dmaidi 244
Activities Sort
Activity Duration LS TF Resource
Cost ($)
unit
A 1 1 0 8H
200
B 9 2 0 9H
450
D 9 8 6 9H
900
C 5 10 8 7H
500
G 5 11 0 5H
250
E 4 15 8 4H
400
I 9 16 0 8H
450
Activity sort with LS time as Major sort & TF and duration as Minor Sorts
F 8 Nabil Dmaidi
17 6 5H 245
Time-Cost Trade-off
The previous analysis suggests that in performing
Time-Cost Trade-off analysis, it is necessary to
determine the cost of decreasing the critical path
by one time unit (day, month & etc).
The cost will vary depending upon which activity
duration decreased.
Usually, select the activity with least shortening
costs. (lowest additional cost per day of
shortening) to minimize the additional costs of
shortening.
Nabil Dmaidi 246
Reducing Project Duration
As the critical path of the network
decreased, some non-critical activities lose
some amount of their total float.
A
B
C
D
F
Nabil Dmaidi 247
Reducing Project Duration
Thus, the extent to which an activity can be shortened and
still has the effect of shortening the project is limited by
the amount of total float exists in the parallel activities.
A
B
C
D
F
Nabil Dmaidi 248
Reducing Project Duration
As the projects duration decreases, the number of
critical paths through the network increases.
A
B
C
D
F
Nabil Dmaidi 249
Reducing Project Duration
If more than one critical path exist, it is necessary to
reduce all critical paths in the network simultaneously,
which becomes expensive.
A
B
C
D
F
Nabil Dmaidi 250
Four Different Solutions for Each
Network
The schedule can be viewed in several different ways in
order to satisfy the client. A client may with to perform
the project in the lease cost, or in the least time. Or in
any manner satisfies him.
1) All Normal: the original network and activity duration
result in all normal solution, based on each activity being
performed in its “NORMAL” least cost manner.
Remember, it is not necessarily the least cost or least
time solution to schedule a project.
Nabil Dmaidi 251
Four Different Solutions for Each
Network
2) Least Cost: considering both direct and
indirect costs, it may be possible to find a
project duration that minimizes these total
costs. By paying more to decrease one or
more critical activity (direct cost) and save
greater indirect costs. (Means that the
result will be total cost saving.)
Nabil Dmaidi 252
Total project costs
Project
Costs
Direct costs
indirect costs
Project duration
Nabil project costs to project duration
General relation ofDmaidi 253
Four Different Solutions for Each
Network
3) Least Time: A project can be shortened
beyond its least cost duration. Until a
point reached where no activities in the
critical path can be physically shortened
regardless of how many resources are
applied. (results in higher costs)
Nabil Dmaidi 254
Four Different Solutions for Each
Network
4) All crash: in this solution, every activity has been
shortened as much as physically possible. Its
duration the same as the least time solution, but
its costs greater. Because the direct cost
increases without further reductions in the
indirect costs.
A fully crashed schedule occurs when all
activities shortened to their shortest possible
duration.
Nabil Dmaidi 255
Four Different Solutions for Each
Network
All crash
It is not an efficient approach since some
non-critical activities will be shortened
without having any shortening influence
on the project duration.
Nabil Dmaidi 256
Logically reducing Project
Duration
The logical approach is to shorten those
activities that contribute to reduce the
project duration.
To begin the time-cost trade-off in a rational
manner, basic calculations needed.
First compute the early start and early finish
times for each activity.
Nabil Dmaidi 257
Reducing Project Duration to shortest possible duration
B E H
0 4
2 7 2 9 3 13 16 7 16
9 0 0 9 12 4 4 16 23 0 0 23
0
0
0 0
A C F J L
0 0 2
1 1 1 2 6 3 9 7 9 16 5 18 23 5 23
1
2 0 0 2 8 1 1 9 16 0 0 16 21 2 2 23 28 0 0 28
0
0 4
D 0 G K
2 3 9 5 8 12 3 16 3 20
5 0 7 12 13 3 7 20 19 4 4 23
ES Dur. LS
EF FF TF LF
Nabil Dmaidi 258
Logically reducing Project
Duration
By computing the link lag values between
activities. (Lag = ESB – EFA). It is logical that
there is at least one path between the first activity
and last activity where lag values are 0.
These activities forming the critical path. (other
solution can be derived by computing TF).
In the previous network. Activity A,B,F,H and L
forming the critical path.
Nabil Dmaidi 259
Logically reducing Project
Duration
To shorten the project’s duration it is essential to shorten
on of the critical activities. A or B or F or H or L.
Without shortening the project will end after 28 days with
a cost of 5300 $.
This is the normal duration cost. And any decrease in
duration will increase the direct cost.
The following table shows information about activities.
Nabil Dmaidi 260
Duration-Cost Data
Activity Normal Crash Normal Crash days to cost per
Duration Duration Cost Cost Shorten
day
A 1 1 800 800 0 --
B 7 4 1000 1600 3
200
C 6 4 300 500 2
100
D 3 2 400 800 1
400
E 3 1 100 200 2 50
F 7 5 500 800 2
150
G 8 4 200 1400 4
300
H 7 6 350 600 1
250
J 5 3Nabil Dmaidi700 850 2 261
75
Identifying activities for 1st
compression cycle
Activity A B F H L
Cost/day ∞ 200$ 150$ 250$
350$
Cannot be shortened Least cost activity to shorten
At any cost
Nabil Dmaidi 262
Logically reducing Project
Duration
From the previous table, it can be noticed that
activity F has the least incremental shortening
cost.( 150 $ per day).
E.g. Shortening F for 2 days costs 150 x 2 = 300 $.
Bear in mind, activities for shortening selected
based on cost per day. Not on cycle cost basis.
Nabil Dmaidi 263
Logically reducing Project
Duration
How many days activity F could be
shortened?
The answer in computing the Network
Interaction Limit (NIL).
So, reducing activity F by 2 days will affect
the link lag values of the succeeding
activities and TF of parallel activities.
Nabil Dmaidi 264
B E H
0 4
2 7 2 9 3 13 16 7 16
9 0 0 9 12 4 4 16 23 0 0 23
0
0
0 0
A C F J L
0 0 2
1 1 1 2 6 3 9 7 9 16 5 18 23 5 23
1
2 0 0 2 8 1 1 9 16 0 0 16 21 2 2 23 28 0 0 28
0
0 4
D 0 G K
2 3 9 5 8 12 3 16 3 20
5 0 7 12 13 3 7 20 19 4 4 23
ES Dur. LS
EF FF TF LF
Nabil Dmaidi 265
B E H
0 2
2 7 2 9 3 13 14 7 14
9 0 0 9 12 2 4 16 21 0 0 21
0
0
0 0
A C F J L
0 0 2
1 1 1 2 6 3 9 5 9 14 5 16 21 5 21
1
2 0 0 2 8 1 1 9 14 0 0 16 19 2 2 21 26 0 0 26
0
0 4
D 0 G K
2 3 7 5 8 10 1 14 3 18
5 0 5 10 13 1 5 18 17 4 4 21
ES Dur. LS
EF FF TF LF
Nabil Dmaidi 266
Summary of the first compression
cycle
Cycle Activity Can be NIL Days Cost Cost Total Project
to shortene shortene per day per cost duration
#
shorten d d cycle
0 -- -- -- -- -- -- 5300 28
1 F 2 3 2 150 $ 300 $ 5600 26
Nabil Dmaidi 267
Identifying activities for 2nd
compression cycle
Activity A B F H L
Cost/day ∞ 200$ ∞ 250$
350$
Nabil Dmaidi 268
B E H
0 2
2 7 2 9 3 13 14 7 14
9 0 0 9 12 2 4 16 21 0 0 21
0
0
0 0
A C F J L
0 0 2
1 1 1 2 6 3 9 5 9 14 5 16 21 5 21
1
2 0 0 2 8 1 1 9 14 0 0 16 19 2 2 21 26 0 0 26
0
0 4
D 0 G K
2 3 7 5 8 10 1 14 3 18
5 0 5 10 13 1 5 18 17 4 4 21
ES Dur. LS
EF FF TF LF
Nabil Dmaidi 269
B E H
0 2
2 6 2 8 3 13 13 7 13
8 0 0 9 11 2 4 16 20 0 0 20
0
0
0 0
A C F J L
0 0 2
1 1 1 2 6 2 8 5 8 13 5 15 20 5 20
0
2 0 0 2 8 0 0 8 13 0 0 13 18 2 2 20 25 0 0 25
0
0 4
D 0 G K
2 3 6 5 8 9 0 13 3 17
5 0 4 9 13 0 4 17 16 4 4 20
ES Dur. LS
EF FF TF LF
Nabil Dmaidi 270
Summary of the 2nd compression
cycle
Cycle Activity Can be NIL Days Cost Cost Total Project
to shortene shortene per day per cost duration
#
shorten d d cycle
0 -- -- -- -- -- -- 5300 28
1 F 2 3 2 150 $ 300 $ 5600 26
2 B 3 1 1 200 200 5800 25
Nabil Dmaidi 271
Identifying activities for 3rd
compression cycle
Activity A B,C F H L
Cost/day ∞ 300 ∞ 250$
350$
Nabil Dmaidi 272
B E H
0 2
2 6 2 8 3 13 13 7 13
8 0 0 9 11 2 4 16 20 0 0 20
0
0
0 0
A C F J L
0 0 2
1 1 1 2 6 2 8 5 8 13 5 15 20 5 20
0
2 0 0 2 8 0 0 8 13 0 0 13 18 2 2 20 25 0 0 25
0
0 4
D 0 G K
2 3 6 5 8 9 0 13 3 17
5 0 4 9 13 0 4 17 16 4 4 20
ES Dur. LS
EF FF TF LF
Nabil Dmaidi 273
B E H
0 2
2 6 2 8 3 10 13 6 13
8 0 0 8 11 2 2 13 19 0 0 19
0
0
0 0
A C F J L
0 0 1
1 1 1 2 6 2 8 5 8 13 5 14 19 5 19
0
2 0 0 2 8 0 0 8 13 0 0 13 18 1 1 19 24 0 0 24
0
0 3
D 0 G K
2 3 5 5 8 8 0 13 3 16
5 0 3 8 13 0 3 16 16 3 3 19
ES Dur. LS
EF FF TF LF
Nabil Dmaidi 274
Summary of the 3rd compression
cycle
Cycle Activity Can be NIL Days Cost Cost Total Project
to shortene shortene per day per cost duration
#
shorten d d cycle
0 -- -- -- -- -- -- 5300 28
1 F 2 3 2 150 $ 300 $ 5600 26
2 B 3 1 1 200 200 5800 25
3 H 1 2 1 250 250 6050 24
Nabil Dmaidi 275
Identifying activities for 4th
compression cycle
Activity A B,C F H L
Cost/day ∞ 300 ∞ ∞ 350$
Nabil Dmaidi 276
B E H
0 2
2 6 2 8 3 10 13 6 13
8 0 0 8 11 2 2 13 19 0 0 19
0
0
0 0
A C F J L
0 0 1
1 1 1 2 6 2 8 5 8 13 5 14 19 5 19
0
2 0 0 2 8 0 0 8 13 0 0 13 18 1 1 19 24 0 0 24
0
0 3
D 0 G K
2 3 5 5 8 8 0 13 3 16
5 0 3 8 13 0 3 16 16 3 3 19
ES Dur. LS
EF FF TF LF
Nabil Dmaidi 277
B E H
0 2
2 4 2 6 3 8 11 6 11
6 0 0 6 9 2 2 11 17 0 0 17
0
0
0 0
A C F J L
0 0 1
1 1 1 2 4 2 6 5 6 11 5 12 17 5 17
0
2 0 0 2 6 0 0 6 11 0 0 11 16 1 1 17 22 0 0 22
2
0 1
D 0 G K
2 3 3 5 8 6 0 13 3 14
5 0 1 6 13 0 1 14 16 1 1 17
ES Dur. LS
EF FF TF LF
Nabil Dmaidi 278
Summary of the 4th compression
cycle
Cycle Activity Can be NIL Days Cost per Cost per Total Project
to shorten shortened shortened day cycle cost duration
#
0 -- -- -- -- -- -- 5300 28
1 F 2 3 2 150 $ 300 $ 5600 26
2 B 3 1 1 200 200 5800 25
3 H 1 2 1 250 250 6050 24
4 B,C 2 3 2 300 600 6650 24
Nabil Dmaidi 279
Identifying activities for 5th
compression cycle
Activity A B,C F H L
Cost/day ∞ ∞ ∞ ∞ 350$
Nabil Dmaidi 280
B E H
0 2
2 4 2 6 3 8 11 6 11
6 0 0 6 9 2 2 11 17 0 0 17
0
0
0 0
A C F J L
0 0 1
1 1 1 2 4 2 6 5 6 11 5 12 17 5 17
0
2 0 0 2 6 0 0 6 11 0 0 11 16 1 1 17 22 0 0 22
2
0 1
D 0 G K
2 3 3 5 8 6 0 13 3 14
5 0 1 6 13 0 1 14 16 1 1 17
ES Dur. LS
EF FF TF LF
Nabil Dmaidi 281
B E H
0 2
2 4 2 6 3 8 11 6 11
6 0 0 6 9 2 2 11 17 0 0 17
0
0
0 0
A C F J L
0 0 1
1 1 1 2 4 2 6 5 6 11 5 12 17 4 17
0
2 0 0 2 6 0 0 6 11 0 0 11 16 1 1 17 21 0 0 21
2
0 1
D 0 G K
2 3 3 5 8 6 0 13 3 14
5 0 1 6 13 0 1 14 16 1 1 17
ES Dur. LS
EF FF TF LF
Nabil Dmaidi 282
Summary of the 5th compression
cycle
Cycle Activity Can be NIL Days Cost per Cost per Total Project
to shorten shortened shortened day cycle cost duration
#
0 -- -- -- -- -- -- 5300 28
1 F 2 3 2 150 $ 300 $ 5600 26
2 B 3 1 1 200 200 5800 25
3 H 1 2 1 250 250 6050 24
4 B,C 2 3 2 300 600 6650 22
5 L 1
∞ 1 350 350 7000 21
Nabil Dmaidi 283
Identifying activities for 6th
compression cycle
Activity A B,C F H L
Cost/day ∞ ∞ ∞ ∞ ∞
Nabil Dmaidi 284
Exercise
Reduce the following project to its shortest
duration.
Nabil Dmaidi 285
B E
10 9
A C F H
1 5 6 6 5
D G
8 9
ES Dur. LS
EF FF TF LF
Nabil Dmaidi 286
Duration-Cost Data
Activity Normal Crash Normal days to cost per
Duration Duration Duration Cost shorten day
A 5 5 100 0 --
B 10 7 500 3 20
C 6 4 300 2 50
D 8 6 400 4 100
E 9 5 200 4 30
F 6 5 100 1 40
G 9 7 320 2 40
H 5 4 410 1 90
Nabil Dmaidi 287
B E
0
6 10 16 9
16 25
0 0
4
A C F H
0 2 5
1 5 6 6 14 6 25 5
6 12 20 30
0
0 2
D 0 G
6 8 14 9
14 23
ES Dur. LS
EF FF TF LF
Nabil Dmaidi 288
Identifying activities for 1st
compression cycle
Activity A B E H
Cost/day ∞ 20 30 90
Nabil Dmaidi 289
B E
0
6 10 16 9
16 25
0 0
4
A C F H
0 2 5
1 5 6 6 14 6 25 5
6 12 20 30
0
0 2
D 0 G
6 8 14 9
14 23
ES Dur. LS
EF FF TF LF
Nabil Dmaidi 290
B E
0
6 8 14 9
14 23
0 0
2
A C F H
0 2 3
1 5 6 6 14 6 23 5
6 12 20 28
0
0 0
D 0 G
6 8 14 9
14 23
ES Dur. LS
EF FF TF LF
Nabil Dmaidi 291
Summary of the 1st compression
cycle
Cycle Activity Can be NIL Days Cost per Cost per Total Project
to shorten shortened shortened day cycle cost duration
#
0 -- -- -- -- -- -- 2330 30
1 B 3 2 2 20 40 2370 28
Nabil Dmaidi 292
Identifying activities for 2nd
compression cycle
Activity A B,D E,G H
Cost/day ∞ 120 70 90
Nabil Dmaidi 293
B E
0
6 8 14 9
14 23
0 0
2
A C F H
0 2 3
1 5 6 6 14 6 23 5
6 12 20 28
0
0 0
D 0 G
6 8 14 9
14 23
ES Dur. LS
EF FF TF LF
Nabil Dmaidi 294
B E
0
6 8 14 7
14 21
0 0
2
A C F H
0 2 1
1 5 6 6 14 6 21 5
6 12 20 26
0
0 0
D 0 G
6 8 14 7
14 21
ES Dur. LS
EF FF TF LF
Nabil Dmaidi 295
Summary of the 2nd compression
cycle
Cycle Activity Can be NIL Days Cost per Cost per Total Project
to shorten shortened shortened day cycle cost duration
#
0 -- -- -- -- -- -- 2330 30
1 B 3 2 2 20 40 2370 28
2 E,G 2 3 2 70 140 2510 26
Nabil Dmaidi 296
B E
0
6 8 14 7
14 21
0 0
2
A C F H
0 2 1
1 5 6 6 14 6 21 5
6 12 20 26
0
0 0
D 0 G
6 8 14 7
14 21
ES Dur. LS
EF FF TF LF
Nabil Dmaidi 297
Identifying activities for 3rd
compression cycle
Activity A B,D E,G H
Cost/day ∞ 120 ∞ 90
Nabil Dmaidi 298
B E
0
6 8 14 7
14 21
0 0
2
A C F H
0 2 1
1 5 6 6 14 6 21 5
6 12 20 26
0
0 0
D 0 G
6 8 14 7
14 21
ES Dur. LS
EF FF TF LF
Nabil Dmaidi 299
B E
0
6 8 14 7
14 21
0 0
2
A C F H
0 2 1
1 5 6 6 14 6 21 4
6 12 20 25
0
0 0
D 0 G
6 8 14 7
14 21
ES Dur. LS
EF FF TF LF
Nabil Dmaidi 300
Summary of the 3rd compression
cycle
Cycle Activity Can be NIL Days Cost per Cost per Total Project
to shorten shortened shortened day cycle cost duration
#
0 -- -- -- -- -- -- 2330 30
1 B 3 2 2 20 40 2370 28
2 E,G 2 2 2 70 140 2510 26
3 H 1 ∞ 1 90 90 2600 25
Nabil Dmaidi 301
Identifying activities for 3rd
compression cycle
Activity A B,D E,G H
Cost/day ∞ 120 ∞ ∞
Nabil Dmaidi 302
B E
0
6 8 14 7
14 21
0 0
2
A C F H
0 2 1
1 5 6 6 14 6 21 4
6 12 20 25
0
0 0
D 0 G
6 8 14 7
14 21
ES Dur. LS
EF FF TF LF
Nabil Dmaidi 303
B E
0
6 7 13 7
13 20
0 0
1
A C F H
0 1 1
1 5 6 6 13 6 20 4
6 12 19 24
0
0 0
D 0 G
6 7 13 7
13 20
ES Dur. LS
EF FF TF LF
Nabil Dmaidi 304
Summary of the 4th compression
cycle
Cycle Activity Can be NIL Days Cost Cost Total Project
to shortene shortene per day per cost duration
#
shorten d d cycle
0 -- -- -- -- -- -- 2330 30
1 B 3 2 2 20 40 2370 28
2 E,G 2 2 2 70 140 2510 26
3 H 1 ∞ 1 90 90 2600 25
4 B,D 1 2 1 120 120 2720 24
Nabil Dmaidi 305
Nabil Dmaidi 306
Communicating
the Schedule
Nabil Dmaidi 307
Communicating the Schedule
Anticipated User
– Top management - No need for great details
– Middle Management - looking for detailed breakdown covering
long time span.
– Low-level Management - Superintendents, foreman - detail
information, cover short period of time.
Communicating Devices
– Verbal and written instructions and reports
– Tabular format
– Graphical representation
bar chart
time scaled
Nabil Dmaidi 308
Time-Scaled Arrow Diagram
Remodeling Chemical Laboratory
Nabil Dmaidi 309
Nabil Dmaidi 310
Project Control
DR. Nabil Dmaidi
Project Control
Major objectives for a good control plan:
1. Should accurately represent the work.
2. Permit deviations to be detected, evaluated and
forecasted.
3. Should make provision for periodic corrective
actions.
DR. Nabil Dmaidi
Level of Control
Small projects - low cost - short duration
– Detailed network
– Reporting mechanism
Middle-sized projects (300 activities)
– Detailed network
– Summary network
– Area and craft network
DR. Nabil Dmaidi
Target Activities Properties
The scheduler has to choose between early start
schedule or target schedule.
Two Major Considerations:
1. The way in which the resources are applied
to the activity.
2. The manner in which the activity is to be
measured.
In all the previous work we assumed that each
activity has a constant rate of utilization.
DR. Nabil Dmaidi
We will keep this assumption knowing that the
most probable one is
If an activity has expended a third of its cost, the
activity is said to be one-third finished.
The most important consideration in measuring
the completion of activities is that the measure
should be consistent throughout the project.
DR. Nabil Dmaidi
Target Activity Durations
DR. Nabil Dmaidi
Monitoring the Project
1. Feedback from direct contact
– Efficient but requires close cooperation
between the manager and field personnel.
DR. Nabil Dmaidi
Monitoring the Project (cont.)
2. Feedback from photography
– Record progress and provide permanent
documentation of the work.
– Tell nothing about the time taken to perform the
work.
DR. Nabil Dmaidi
Monitoring the Project (cont.)
3. Feedback from check-off list
– Planner prepares a check-off list that is started,
to be continued, or to be finished in the next
time interval.
– Effective if the reporting periods are short
“Daily, Weekly” and small number of activities
involved.
– Disadvantage: false reporting
DR. Nabil Dmaidi
Monitoring the Project (cont.)
4. Feedback from bar chart
5. Feedback from networks
Advantage:
Superintendent has complete information about
the status of the project.
Disadvantage:
Diagram may appear confusing to field
personnel.
DR. Nabil Dmaidi
Setting the Target Schedule
Early Start Schedule: As Target for Control
– Problem:
Required high effort to keep the plan working
Late Start Schedule As Target for Control
– Problem:
Because every activity is timed to start as its latest,
project overruns are sure to follow.
DR. Nabil Dmaidi
Target Schedule
Activities may be positioned early or late
start or somewhat in between.
Non-critical activities allow intermediate
start.
DR. Nabil Dmaidi
Anticipated target S-Curve
DR. Nabil Dmaidi
The S-Curve field
DR. Nabil Dmaidi
Sample Project Cost Data
Cos t T o ta l
D u ra tio R a te Cos t
A c tiv ity n (D a y s ) ($ /D a y ) ($ )
A 2 500 1,000
B 17 200 3,400
C 3 300 900
D 5 100 500
E 6 2,000 12,000
F 2 500 1,000
G 1 1,000 1,000
DR. Nabil Dmaidi
Early Start Tree
DR. Nabil Dmaidi
Late Start Tree
DR. Nabil Dmaidi
Target Network
DR. Nabil Dmaidi
Project S-Curve
DR. Nabil Dmaidi
Actual Versus Target S-Curves
DR. Nabil Dmaidi
Earned Value Analysis
Nabil Dmaidi 331
Earned Value Analysis (EVA)
Foundations of modern cost control
What’s more important?
– Knowing where you are on schedule?
– Knowing where you are on budget?
– Knowing where you are on work accomplished?
Earned Value Analysis (EVA) addresses all three:
– It compares the PLANNED amount of work with what has
actually been COMPLETED to determine if COST,
SCHEDULE, and WORK ACCOMPLISHED are
progressing as planned.
Nabil Dmaidi 332
332
EVA Terminology
BCWS – Budgeted Cost of Work Scheduled
– Planned cost of the total amount of work scheduled to be
performed by the milestone date. (a.k.a. your original plan)
BCWP – Budgeted Cost of Work Performed
– The planned (not actual) cost to complete the work that has
been done.
– Also known as “Earned Value”
ACWP – Actual Cost of Work Performed
– Cost incurred to accomplish the work that has been done to
date.
Nabil Dmaidi 333
333
Input data for EVA
Activity schedule, usually in the form
of a bar chart.
Budgeted cost for each activity.
Percent complete for each activity.
Cost to date for each activity.
Nabil Dmaidi 334
334
Information Needed to Compute
Budgeted Cost of Work Scheduled (BCWS)
Activity budget at completion (BAC)
Activity schedule
Data date
Budgeted Cost of Work Performed (BCWP)
Activity budget at completion (BAC)
Physical activity progress as a percentage of its total work
Actual Cost of Work Performed (ACWP)
Each activity’s cost to date from the job costing system
Nabil Dmaidi 335
335
Earned Value Reporting - Costs
Budgeted Cost of Work
Performed (BCWP) =
CV BCWP ACWP earned value of project
BCWP Actual Cost of Work
CPI Performed (ACWP)
ACWP
Cost Variance (CV)
CPI = 1, on budget – Difference between
CPI < 1, over budget earned and actual costs
CPI > 1, under budget
for the completed work
Cost Performance Index
(CPI or CI)
Nabil Dmaidi 336
336
Earned Value Reporting - Schedule
Budgeted Cost of Work
Performed (BCWP)
SV BCWP BCWS Budgeted Cost of Work
Scheduled (BCWS)
BCWP
SPI Schedule Variance (SV)
SV BCWP BCWS
BCWS SPI BCWP – Difference between the
BCWS
value of work that was
SPI = 1, on schedule planned for completion and
SPI < 1, behind schedule
SPI > 1, ahead of schedule the value of the work that
was actually completed
Schedule Performance Index
(SPI or SI)
Nabil Dmaidi 337
337
Earned Value Reporting
(budgeted)
(earned)
(actual)
Nabil Dmaidi 338
Earned Value Reporting –
Activity A Example
Week BCWS BCWP ACWP
1 300 500 500
2 300 500 500
3 300 300 300
4 300 200 200
From: SBG
Nabil Dmaidi 339
339
Earned Value Reporting –
Activity B Example
Week BCWS BCWP ACWP
1 1000 1000 1000
2 1000 1000 1000
3 1000 500 500
4 0 500 500
From: SBG
Nabil Dmaidi 340
340
Earned Value Reporting –
Activity C Example
Week BCWS BCWP ACWP
1 814 300 814
2 814 400 686
3 814 500 1000
4 814 428 400
From: SBG
Nabil Dmaidi 341
341
Earned Value Reporting – Project
(Activities A, B, C) Example
Week BCWS BCWP ACWP
1 2114 1800 2314
2 2114 1900 2186
3 2114 1300 1800
4 1114 1128 1100
From: SBG
Nabil Dmaidi 342
342
Earned Value Reporting – Project
(Activities A, B, C) Example
SI CI
From: SBG
Nabil Dmaidi 343
343
Earned Value Reporting – Project
(Activities A, B, C) Example
Graph shows
trend of cost
(CI)
and schedule
indices
From: SBG
Nabil Dmaidi (SI) 344
Schedule and Estimated
Costs Class Exercise: BCWS
Week Week
Task Est. Cost Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9
1 10
Mobilization 100%
2,000
Grubbing 100%
5,000
Bridge Excavation
2,000
100% Data Date
Install Prefabricated
100%
Bridge 47,000
Back Fill Bridge 100%
2,000
Install Culverts 100%
10,000
Rough Excavate Roadway 25% 25% 25% 25%
112,000
Install Sanitary Sewer 50% 50%
57,000
Install Water Lines 50% 50%
69,000
Install Storm Drains 100%
15,000
Grade and Roll Sub Grade 50% 50%
12,000
Place and Compact Road
100%
Base 42,000
Example:
Place and Compact Asphalt 10,000 x 100% 100%
48,000
+ 112,000 x 25%
Grade Shoulders
3,000 = 38,000 100%
Cleanup 100%
1,000
Demobilize 100%
2,000
Cost/wk using estimate &
schedule 429,000 7,000 51,000 Nabil Dmaidi
38,000 55,500 96,000 6,000 345
345
Class Exercise: BCWP
Actual Percent Performed per
Week
Week
Task Est. Cost Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9
10
Mobilization 2,000 90% 10%
Grubbing 5,000 100%
Bridge Excavation 2,000 100%
Install Prefabricated Bridge 47,000 90% 10%
Back Fill Bridge 2,000 90% 5% 5%
Install Culverts 10,000 80% 20%
Rough Excavate Roadway 112,000 10% 25% 30% 5% 30%
Install Sanitary Sewer 57,000 20% 50%
Install Water Lines 69,000 50%
Install Storm Drains 15,000
Grade and Roll Sub Grade 12,000
Place and Compact Road Base 42,000
Place and Compact Asphalt 48,000
Grade Shoulders 3,000
Cleanup 1,000
Demobilize 2,000
Cost at Estimated values 429,000 6,800 46,300 24,000
Budgeted Cost of Work
(BCWP) 6,800 53,100 77,100
Performed
Data Date
Nabil Dmaidi 346
346
Class Exercise: ACWP
Actual Costs
Actual Week
Task Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9
Cost 10
Mobilization 2,119 1,907 212
Grubbing 5,386 5,386
Bridge Excavation 2,265 2,265
Install Prefabricated Bridge 40,537 36,483 4,054
Back Fill Bridge 2,035 1,832 102 102
Install Culverts 9,828 7,862 1,966
Rough Excavate Roadway 108,857 10,886 27,214 32,657 5,443 32,657
Install Sanitary Sewer 60,482 12,096 30,241
Install Water Lines 64,066 32,033
Install Storm Drains 14,473
Grade and Roll Sub Grade 12,439
Place and Compact Road Base 40,298
Place and Compact Asphalt 48,835
Grade Shoulders 2,835
Cleanup 863
Demobilize 1,961
Actual Totals 417,280 7,293 40,792 22,903
Actual Cost of Work
(ACWP) 7,293 48,085 70,989
Performed
Data Date
Nabil Dmaidi 347
347
Class Exercise: SPI and CPI
Performance Indexes
Actual Week
Task Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 Week 10
Cost 1
Schedule Performance
(SPI) 97.14% 91.55% 80.31%
Index
Cost Performance Index (CPI) 93.24% 110.43% 108.61%
Nabil Dmaidi 348
348
Rolling Up EVA Measures
Nabil Dmaidi 349
349
Linear Scheduling Method
Nabil Dmaidi 350
Linear Scheduling Method
Definition
A simple diagram to show location and time
at which a certain crew will be working on a
given operation.
Nabil Dmaidi 351
Characteristics
Shows repetitive nature of the construction.
Progression of work can be seen easily.
Sequence of different work activities can be easily
understood .
Have fairly high level of detail.
Can be developed and prepared in a shorter time
period than other formats.
Nabil Dmaidi 352
Advantages of LSM
Provides more information concerning the
planned method of const. than a bar chart.
In certain types of projects, LSM offers
some advantages over the network
approach.
Nabil Dmaidi 353
Line of Balance Technique
LSM has relationships to the line of balance
(LOB) technique, developed by US. Navy
in the early 1950s.
First applied to industrial manufacturing
and production control.
Nabil Dmaidi 354
Three diagrams are used in LOB:
1. Production Diagram
Shows the relationships of the assembly operations
for a single unit. Similar to AOA, except that it
shows only one unit of production.
2. Objective Diagram
Used to plot the planned or actual number of units
produced vs. time. LSM diagram resembles this
diagram.
3. Progress Diagram
Shows the number of units for which each of the
subassembly operations has been completed.
Nabil Dmaidi 355
Difference between Objective
Diagram and LSM :
O.D. is used to schedule or record the
cumulative events of unit completion.
LSM is used to plan or record progress
on multiple activities that are moving
continuously in sequence along the
length of a single project.
Nabil Dmaidi 356
Implementation of LSM
Can be used for continuous activities rather
than discrete activities.
Transportation projects; highway const.,
highway resurfacing and maintenance, airport
runway const. and resurfacing, tunnels, mass
transit systems, pipelines, railroads.
High-rise building construction
Repetitive building units
Nabil Dmaidi 357
Elements of the LSM
Axis Parameters
Location
Measure of progress.
In high-rises and housing const., measures
may be stories, floors, subdivisions,
apartments, housing units
In Transportation projects, distance (ft. or
mile can be used, but division by stations
(100ft.) is common) is general.
Nabil Dmaidi 358
Time
Hours, days, week, or month - depends on
the total project time and level of detail
desired in the schedule.
Preferable to prepare the schedule based on
working days and convert to calendar days
only at the end.
Nabil Dmaidi 359
Activity Production Rates
Obtained by the usual estimating methods
as a function of the activity, equip.
characteristics, labor, and job conditions.
The initial rate should be associated with
the min. direct cost of accomplishing the
single activity.
Nabil Dmaidi 360
Activity Interruption and Restraint
Prod. rate may vary with locations or time
periods.
Progress may be interrupted intentionally
and restraints may occur between activities
due to limited equip. or crews.
Nabil Dmaidi 361
Buffers
When const. activities progress
continuously in a chain, some spacing
between activities is required.
This spacing serves as a buffer and may
require distance or time interval between
activities.
Nabil Dmaidi 362
Activity Intervals
Used to describe the period of time between the
start and finish of an activity at a particular
location.
Intervals can be indicated by a broad line, two
narrow lines, etc.
Monitoring Progress
Working calendar can be marked with a moving
symbol or a line, tape, etc. vertically across the
diagram.
Progress on individual activities would be marked
by location rather than time.
Nabil Dmaidi 363
1. Project Time Optimization
The total project time may be such that
indirect costs and liquidated damages
assessed are more costly than the expense of
accelerating certain activities.
Cost-duration analysis can be used to
minimize the total cost, as follows :
Nabil Dmaidi 364
a) Identify all activities that can be accelerated or
decelerated.
b) Among the above, consider only those that are at a
buffer limitation at both the start and the finish of the
activity.
c) Of these, select the one activity with the lowest cost
slope associated with acceleration (or deceleration).
d) Accelerate (or deceleration) the activity rate of
production the maximum feasible amount.
e) Repeat the above steps successively until the optimum
project cost and associated duration are obtained.
Nabil Dmaidi 365
2. Discrete Activities
Discrete are best scheduled by other methods.
Once the duration is determined by network
analysis, it can be scheduled on the LSM
diagram and coordinated with the linear
activities.
3. Seasonal Adjustments
When developing LSM, appropriate
adjustments can be made for seasonal effect on
construction progress.
Nabil Dmaidi 366
4. Project Progress and Resource Management
Project progress is often estimated by the S-
curve with bar chart development.
In LSM, the determination of activity
progress is facilitated and made more
rigorous.
Nabil Dmaidi 367
LSM Schedule
4
3
2
1
2 4 6 8 10 12 14 16 1820 22 24
Nabil Dmaidi 368
LSM Schedule with Brickwork
4
3
2
1
2 4 6 8 10 12 14 16 1820 22 24
Buffer
Nabil Dmaidi 369
Four-unit Duplex I-J Fragnet
2 7 8
EXC FNDS F&P FNDS FRAME
BLDG 1 & SLAB BLDG 1
BLDG 1
2 7 8
EXC FNDS F&P FNDS FRAME
BLDG 2 & SLAB BLDG 2
BLDG 2
2 7 8
EXC FNDS F&P FNDS FRAME
BLDG 3 & SLAB BLDG 3
BLDG 3
2 7
EXC FNDS F&P FNDS
BLDG 4 & SLAB
BLDG 4
Nabil Dmaidi 370
LSM Schedule
Duplex Number
4
3
2
1
2 4 6 8 10 12 14 16 18
Days
Nabil Dmaidi 371
LSM Schedule
Duplex Number
4
3
2
1
2 4 6 8 10 12 14 16 18
Days
Nabil Dmaidi 372
