MTDE 333 / 633
Project Management for Engineers
Project Scheduling - II
Spring 2025
Instructor:
Dr. Walter Olarte
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Alternative Relationships
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Alternative Relationships

Until now we assumed that a successor activity can start as soon as
all predecessor activities have been completed (and that it must
start then)
End of Activity A
Activity A
Start of Activity B
Activity B
However…

Sometimes we want the successor to be delayed (or expedited)
somewhat from the end date of a predecessor

Lag and lead relationships are used in such cases
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Leads and Lags

6.3.2.3 Leads and Lags:
 “A lag is the amount of time whereby a successor
activity will be delayed with respect to a predecessor
activity”
©2013 Project Management Institute. A Guide to the Project Management
Body of Knowledge (PMBOK® Guide) – Fifth Edition, Page 159
A lead (negative lag) between the predecessor and
successor would imply an overlap
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Precedence Diagramming
A 5-day lag between predecessor and successor:
5 days
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Precedence Diagramming and
Conventions other than Finish-to-Start
Start-to-start relationship:
5 days
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Precedence Diagramming and
Conventions other than Finish-to-Start
Finish-to-finish relationship:
5 days
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Precedence Diagramming and
Conventions other than Finish-to-Start
Start-to-finish relationship:
Note:
 Not commonly used
 Often prohibited by scheduling specification
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Multiple PDM Relationships (Page 213)
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Summary of Planning Process
List stakeholders
 Determine project scope with stakeholders
 Develop WBS to identify schedule activities
 Create a table indicating predecessors.


Using the table helps to ensure that no necessary dependencies
are overlooked
Draw network diagram
 Do forward and backward pass to determine critical path
and lags
 Decisions regarding early and late start of activities
 Draw Gantt chart

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5
Scheduling with Resource
Constraints
Determining Activity Duration
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Scheduling with Resource Constraints
The project can theoretically be done within 4 days
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6
Scheduling with Resource Constraints
If Activity B and Activity C must
be done by the same resource,
the project will take longer
Example:
One engineer
must perform
Activity B
and
Activity C
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Resource Allocation, Workload, and
Resource Loading

Resource allocation refers to assigning one or more
resources to an activity or project

Workload refers to the amount of work imposed on a
resource. (of a particular resource)

Resource loading refers to the amount of a particular
resource needed to conduct all the activities in a project
to which the resource is allocated.
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7
Resource Allocation, Workload, and
Resource Loading
Perspective of a
The workload of an individual resource
(i.e. one engineer) can be indicated as:
 man-hours
 % of the full workload potential
The resource loading (i.e. system
engineers) can be expressed as:
 # of hours needed
 # of days needed
particular
resource
Perspective of
the project
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Scheduling with Resource Constraints:
Workload
You need a company-wide
system to manage the
workload on all projects
concurrently
Why should smaller projects
be loaded onto the system as
well?...
The aggregate of many
small projects
contributes to the
workload and the total
resource requirements
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8
Class Exercise
Scheduling with Resource Constraints
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Scheduling with Resource Constraints
Class Exercise
Solve Review Problem No 19
on Page 232
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Class Exercise
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Solution



Practical implications:
If you have several activities to do and other people are waiting for
deliverables from you, it is often wise to do the activities with shortest
duration first (this is the shortest task time priority rule discussed in Chapter
7)
Determine which resource has the heaviest workload and develop the
schedule around her workload
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10
Resource Leveling
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Scheduling with Resource Constraints:
Resource Leveling
Resource Leveling:
“Any form of schedule network analysis in which
scheduling decisions (start and finish dates) are driven by
resource constraints
Examples:
 Limited resource availability
 Difficult-to-manage changes in resource availability
levels
-PMBOK
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Resource Leveling of a Time-Constrained
Project
The LOGON Project
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0
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TF
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ES
EF
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41
LS
LF
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Resource Leveling of a Time-Constrained
Project
The LOGON Project
Labor
Equipment
47 weeks
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Resource Leveling of a Time-Constrained
Project
Fluctuations in workload
are difficult to manage
47 weeks
However,
We can use float to
reduce fluctuations!..
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Resource Leveling of a Time-Constrained
Project
• P & Q will start 2
weeks later
• U will start 5 weeks
later
47 weeks
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Resource Leveling
During resource leveling activities can be split (to jump
between activities) but it often has a negative effect
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Leveling Multiple
Resources
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Resource Leveling: Multiple Resources
• Reducing overload or improving difficult-tomanage fluctuations in workload of one
resource sometimes leads to overloading or
more fluctuations in workload of other resources
Example:
Resource 1 = Workers
&
Resource 2 = Equipment
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Resource Leveling: Multiple Resources
Improved
WORKERS loading
Disrupted
EQUIPMENT loading
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Leveling of a Resource-Constrained
Project
• Projects are time-constrained
• What happens if the project is also resourceconstrained? - When the maximum availability of a
resource is a constraint, the duration of the project
often must be increased
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Leveling of a Resource-Constrained
Project
When we have limited
resources
(i.e.15 workers)
What if we only
have 14 workers
available?...
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Leveling of a Resource-Constrained
Project
•
Some activities will
have to be delayed
beyond their late
start (LS)
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Scheduling Process
Computerized planning systems
develop the following three items
concurrently:
1. Network
2. Gantt chart
3. Resource Loading
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Scheduling with Calendars
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Schedule Calendar
The schedule must use the “Work Calendar” of the resources
to calculate the start and finish dates.
Non-work days to be accounted for:


Labor (i.e., weekends, holidays, vacations, severe weather)
Equipment and Tools (i.e., maintenance days, severe
weather)
Example: When is the 10-day activity planned to finish?...
WC-A
WC-B
Monday
Tuesday
1
2
Monday
Tuesday
1
2
Wednesday Thursday
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4
Wednesday Thursday
3
4
Friday
Saturday
Sunday
Monday
Tuesday
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6
7
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9
Friday
Saturday
Sunday
Monday
Tuesday
6
7
5
Wednesday Thursday
Friday
Saturday
Sunday
Friday
Saturday
Sunday
10
Wednesday Thursday
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10
Computerized systems perform this function!
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Schedule Calendar
Other considerations:
 Resource constraints – create non-workdays due to
unavailable resources
 Risk of changes – create non-workdays to postpone
the start of activities that might change (scope)
 Cash flow – create non-workdays to improve the
project cash flow or exchange rate
 Logistics – create non-workdays to delay a delivery of
an item for which there is no space in the jobsite
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