Scheduling CTC415 Activity Network Development Network Models Activity

Scheduling CTC-415

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 are 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 • Easy to see 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

Constructing an AON Network • 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

Constructing an AON Network • Combinational Logic – 2 or more activities can be worked at one time after multiple predecessor activities are finished

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

Logic Errors and Problems – Logic Loops

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

Constructing a AON • Determine the relationships between the activities • Forward Pass – Determine when each activity can start based on the finish of the predecessor activities • Backward Pass – Determine when each activity can start based on when the successor activities start

Constructing a AON Activity A B C Duration 6 4 10 Predecessors START A B D E F G H I END 10 1 6 8 10 6 C D, G, I A F A H E

Constructing a AON • Critical Path – Path through schedule which provides the shortest time to complete project • Total Float – Amount of time that activity can float without impacting CP • Free Float – Amount of time an activity can be delayed without effecting the early start date of the predecessor activity