Scheduling. Putting the activities in chronological order –Chicken or the egg Allows the PM to determine the time required to complete a project

Scheduling

Scheduling

• Putting the activities in chronological order– Chicken or the egg

• Allows the PM to determine the time required to complete a project

Types of Schedules

• Depend on Viewer– Simple bar chart (Gantt chart)

• Tells owner progress

– Activity on Node (AON)– Activity on Arrow (AOA)

• Used by PM, supers, foremen

Developing Activity Sequence

• Physical Relationship• An activity cannot start until a previous one is complete

• Safety Relationship• Performing activities which cause a safety hazard to other

activities

• Resource Relationship• The amount of resources available at any time

• Preferential Relationship• Contractors preference on activity order

Constructing Bar Chart

• How should bar chart be laid out– Time on horizontal axis– Activity on vertical axis– Time of activity start based on position– Duration of activity based on length of line

• Day = start of day to start of day


• What time unit should be used– Work days– Hours– Weeks– Bar chart size may dictate time units


• Additional Info– Activity Value– Activity Cost– Activity Resource requirements


• Work days or Calendar days– Work days harder to follow

• No weekends or holidays

– Calendar days allow you to see concrete curing

Gantt Chart

• Looks like a horizontal bar chart

• Good for linear work

• Good for providing an overview of the project

• Not good for complex projects

Gantt Chart

ID Task Name Duration

1 Excavate foundation 2d

2 Form footings 1d

3 Pour footings 2d

4 strip footings 1d

5 Form foundation walls 1d

6 Pour foundation walls 3d

7 Strip forms 1d

8 Frame 1st floor 2d

9 Backfill foundation 1d

10 Frame 1st floor walls 2d

11 Frame 2nd floor 2d

12 Frame 2 floor walls 2d

13 Frame 2nd floor ceiling 1d

14 Frame roof 3d

15 Shingle roofing 4d

16 Rough plumbing 3d

17 Rough electric 3d

18 Insulation 2d

19 Drywall 3d

20

21

22

23

24

F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T WApr 7, '02 Apr 14, '02 Apr 21, '02 Apr 28, '02 May 5, '02 May 12

Activity Network Development

• Network Models• Activity on Node• Precedence Diagram Method• Activity on Arrow

• Network Characteristics• Discrete Activities• Deterministic Durations• Deterministic Logic• Activity Flow

Network Elements

• Activities• Basic building block• Represent tasks• Must consume time and resources

• Milestones• Notice to Proceed• Building Enclosed• Substantial Completion• Project Complete

• Activity Relationships• Physical, Safety, Resource, Preferential

Precedence

• Succeeding activities cannot start until preceding activities finished

• Changes in duration of one activity affect all succeeding activities

Activity on Node

• All activities occur at nodes

• Arrows connect nodes and show relationships

Activity on Node

• Basics:• Unique Alphanumeric identifier

• Unique description

• Estimated Duration

• Succeeding activity cannot start until preceding activity is finished

• Need beginning and ending milestone to tie project together

Constructing an AON Network

• Sequential logic– All activities preceding

must be finished before next activity can start

• Concurrent Logic– 2 or more activities can

be worked at one time

100Excavate Footings

2

110Form & Reinforce Ftg

2


2


2

120Install f loor drains


• Multiple Successor Logic– 2 or more activities can be

worked at one time after common predecessor is finished

• Multiple Predecessor Logic– 2 or more activities need to

be finished before next activity starts


2


2



2


2



• Combinational Logic– 2 or more activities can

be worked at one time after multiple predecessor activities are finished


2


2


115Trench for floor drains

Logic Errors and Problems

• Incorrect Logic• Activities MUST have a logical connection

• Paint color does not control the roofing application

• Redundant Logic– Not incorrect– Can cause errors


2


2

120Pour Footing

2

Logic Errors and Problems

– Logic Loops


2


2

120Pour Footing

2

Activity Numbering

• Numbering Activities can make it easier to use schedule

• Group like activities under the same general numbers– Activity Category

• WBS can make it easy to categorize resources used to each activity

– Work Classification• Numbers refer to a class of activity

Activity Numbering

– Location• Number activity based on location on project

– Responsibility• Numbers refer to who is responsible for work

Activity Numbering

• Numbering Conventions– Directional

• Numbers increase from start to finish of project

– Numbering gaps• Leave gaps between numbers to allow for additions

to schedule

– Even/Odd Numbering• Even # = part of base contract• Odd # = additional work

Documents

Scheduling. Putting the activities in chronological order –Chicken or the egg Allows the PM to determine the time required to complete a project