Chapter 10: Critical Path Method

Chapter 10: Critical Path Method

1. 9. Forward Pass

   • process of calculating the early start date (ES) and early finish date (EF) for all the activities
     • ES
       • earliest date by which an activity can start assuming all the preceding activities are completed as planned
     • EF
       • earliest date by which an activity can be completed assuming all the preceding activities are completed as planned
     • For complete calculation process check book

2. 1. Network Diagram

   • graphical presentation of the activities showing the planned sequence of work
   • formed by
     • list of activities
     • logic constraints
   • also called precedence diagram method (PDM)

3. 2. Definition of an Activity

   • step in which each activity is given a description for the work content understanding of the team members. expanded later into a Job card.

4. 3. Logical Reltionship

   • logical elationshipa between activities can be
     • Mandatory
       • limitations ofthe build method, the MUST be done a certain way
     • Discrtionary
       • defined by the body of knowledge
   • Activities in
     • Series
       • performed at the same time, which is a more efficient use oftime than activities in series
     • Paralel
       • carried out one after the other

5. 4. How to draw Logical Relationships

   • logical relationship, constraint, dependency and link are all used interchangeably to represent the lines drawn between the activity boxes

6. 5. Activity Logic Table

   • logic information is often compiled in a tabular format, with each record (or line) defining a relationship.
     • colums: before act., constraints, next act., and or duration

7. 6. Activity Duration

   • info needed
     • Activity duration Activity calendar or work pattern
   • An activity's duration will run from the start to the finish ofthe activity.

8. 7. Calendar and work Pattern

   • activity's working profile, in other words, on what days ofthe week the resources or activity will be working

9. 8. Critical Path Method Steps

   • Steps
     • Draw the logic network diagram
     • Assign durations to all the activities
     • Impose a work calendar.

10. 10. Backward Pass

    • Process of calculating the late start date (LS) and late finish date (LF) of each activity
      • LS
        • The latest date an activity can start to meet the planned completion date.
      • LF
        • The latest date an activity can finish to meet the planned completion date.
    • For complete calculation process check book

11. 11. Activity Float

    • is a measure of flexibility, or inherent surplus time in an activity's scheduling.
      • This indicates how many working days the activity can be delayed or extended before it will extend the completion date of the project or any target finish dates (milestones).

12. 12. Network Diagram

    • Constraints between activities
      • Finish-to-Start (FS)
        • Represents the relationship linking the finish of an activity with the start of another activity.
      • Start-to-Start (SS)
        • represents the relationship between the start dates ofthe two activities.
      • Finish-to-Finish (FF)
        • represents the relationship between the finish oftwo activities.
      • Start-to-Finish (SF)
        • Represents the relationship linking the start of an activity with the finish of another activity.

13. 15. Calendar / Work Pattern

    • number of calendars can be defined.
    • Rest days are the days of the week that are always taken off
    • Holidays can be defined as public holidays, works holidays, or your own personal holidays.
    • Activities and resources can be linked to a calendar number.
    • defines the days on which work can be scheduled.
    • assigned to any of the trades or even one person if appropriate.
    • unique combination of rest days and holidays.

14. 14. Definition of an Activity

    • unique activity code or number
    • An activity may need resources
    • activities can be linked to the work packages
    • activities will have a calendar or work pattern
    • An activity must have a description.
    • logical relationships between the activities
    • will incur expenses
    • activity numbers from the various projects need to be different, when multi project
    • As time and resources are linked to the activities they can be integrated to generate a manpower S curve against time for planning and control purposes
    • The activity can have target start and finish dates assigned
    • An activity may need items to be procured

15. 13. Logical Errors

    • Basic logical errors
      • Logical loop
        • represents an impossible situation
      • Logical dangle
        • where the activity either comes from nowhere or goes to nowhere
      • Redundant precedence relationship
        • it is only necessary to indicate an activity's immediate predecessors, not the one before their predecesor

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