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CE 405 - SCHEDULING

CE 405 - SCHEDULING. Review : Three fundamental steps in developing a Schedule are: Identify the Activities Determine the Durations Establish the Logic al Inter-relationships Activities , Durations , Logic. CE 405 - SCHEDULING. Activities , Durations , Logic

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CE 405 - SCHEDULING

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  1. CE 405 - SCHEDULING Review: Three fundamental steps in developing a Schedule are: • Identify the Activities • Determine the Durations • Establish the Logical Inter-relationships • Activities, Durations, Logic

  2. CE 405 - SCHEDULING Activities, Durations, Logic • None of these three is really a single, stand-alone operation • Experienced Schedulers often think of these three processes as a single process – especially the relation of durations to logic

  3. CE 405 - SCHEDULING What is Logic in the context of a Construction Schedule?

  4. CE 405 - SCHEDULING Logic is the relationship(s) that any given Activity has with all the other Activities in the Schedule. • What interaction does this Activity have with the other Activities? • If you changewhen or how this Activity is done – what happens to the other Activities? – ripple effect

  5. CE 405 - SCHEDULING When you are developing the Logic of your Schedule – • What is the primary consideration that you will be addressing if you want to get the work done as expeditiously as possible regarding each and every Activity?

  6. CE 405 - SCHEDULING Expedited Logic? • What Activities must be completed before I can Start work on this Activity • What Activities can be worked on at the same time that I am working on this Activity.

  7. CE 405 - SCHEDULING The three terms that pertain to the Logic of your Schedule are: • Dependencies

  8. CE 405 - SCHEDULING The three terms that pertain to the Logic of your Schedule are: • Dependencies • Sequential work

  9. CE 405 - SCHEDULING The three terms that pertain to the Logic of your Schedule are: • Dependencies • Sequential work • Concurrent work

  10. CE 405 - SCHEDULING What is your definition of Dependencies in a Schedule?

  11. CE 405 - SCHEDULING Definition of Dependencies? • What work (Activities) must be completed before I can start work on this Activity [Predecessors] • What work (Activities) can not start until work on this Activity is completed [Successors]

  12. Predecessor - controls the start or finish of another activity • Successor - depends on the start or finish of another activity Predecessor to Act. B Successor to Act. B 10-3

  13. CE 405 - SCHEDULING What is your definition of Sequence?

  14. CE 405 - SCHEDULING Definition of Sequence? • A group (string or chain) of Activities that proceed in a logical order – the preceding Activity has to be Substantially Complete before the follow-on Activity can start

  15. Sequence – A group of Activities that logically follow one after the other 10-3

  16. CE 405 - SCHEDULING Review: The term Substantially Complete was used on the preceding slide – what does it mean in relation to a Construction Activity (not the job as a whole)?

  17. CE 405 - SCHEDULING Substantially Complete is when work on a given Activity has proceeded to the point that work on following Activities can Start. • Work on a CMU block wall can start even if the forms have not been stripped off the footings

  18. CE 405 - SCHEDULING What would be the Activity Sequence for a CMU foundation wall?

  19. CE 405 - SCHEDULING Activity Sequence for foundation wall? • Survey/Layout • Excavate • Form/Place Footing • Lay CMU block • Each Successor Activity logically follows the Predecessor Activity

  20. CE 405 - SCHEDULING The third term associated with logic is concurrent – what does this mean?

  21. CE 405 - SCHEDULING Definition of concurrent? • What other Activities can be worked on at the same time that work is proceeding on this Activity?

  22. Concurrent Activities – Activities that can be worked on at the same time Concurrent Activities 10-3

  23. CE 405 - SCHEDULING Definition of concurrent? • After a building is dried-in and the interior is painted – what would be some of the concurrent Activities that could be worked on? • First of all – what does dried-inmean?

  24. CE 405 - SCHEDULING Dried-in definition? • All work necessary to “waterproof” the interior is complete • Shingles are on, doors and windows are in, siding/fascia/soffits are done, etc.

  25. CE 405 - SCHEDULING What concurrent Activities can be accomplished after the building is dried-inand the sheetrock/painting are done?

  26. CE 405 - SCHEDULING Concurrent Activities after dried-in? • Interior finishes – baseboard, trim • Finish electrical work/fixtures • Finish mechanical/HVAC • Finish plumbing • Cabinetry • Flooring

  27. CE 405 - SCHEDULING What three Scheduling Network Systems are most commonly used for Construction Projects?

  28. CE 405 - SCHEDULING 3 Scheduling Network Systems? • Activity-on-Node (AON) [Chptr 6] • Activity-on-Arrow (AOA) [Chptr 7] • Precedence Diagramming Method (PDM – leads, lags) [Chapter 17] • All three use the Critical Path Method (CPM)

  29. CE 405 – SCHEDULINGCRITICAL PATH Critical Path Method (CPM) handout • Logic Boxes – numerous layouts • Combination Convention • BOTD + EOTD [Primavera]

  30. CE 405 – SCHEDULINGCRITICAL PATH Primavera Combination Logic: • BOTD and EOTD combined Forward Pass: EF = ES + Dur – 1 Backward Pass: LS = LF – Dur + 1 Total Float: TF = LS – ES or TF = LF – EF Critical Path: Sequence where TF = 0

  31. CE 405 - SCHEDULING Network Model Characteristics: 1. Discrete Activities 2. Deterministic (vs Probabilistic) Durations 3. DeterministicLogic 4. Activities “Flow” from Start to Finish

  32. CE 405 - SCHEDULING What is the definition of “deterministic”?

  33. CE 405 - SCHEDULING Definition of “deterministic”? • You have “pre-supposed” (i.e. made your mind up) that things will proceed in a preconceived manner to an all ready decided end result (i.e. a foregone conclusion) • Contrasted with “probabilistic”?

  34. CE 405 - SCHEDULING Definition of “probabilistic”? • The likelihood (statistical) that a given alternative or option will happen • Construction Schedules require fixed Start and Finish dates to enable all the participants to Plan the progression of their work • Deterministic = Reasonable Certainty

  35. CE 405 - SCHEDULING Network Elements: • Activities • Milestones • Activity Relationships (Logic)

  36. CE 405 - SCHEDULING Review: What is a Milestone?

  37. CE 405 - SCHEDULING Review: What is a Milestone? • A Milestone marks a “point-in-time” – but unlike an Activity, it does not consume any time within a Construction Schedule

  38. CE 405 - SCHEDULING What are some examples of Milestones that you might build into your Schedule?

  39. CE 405 - SCHEDULING Examples of Milestones? • Notice to Proceed (NTP) • Usually considered to be the first day of your Schedule (Day 1)

  40. CE 405 - SCHEDULING Examples of Milestones? • Notice to Proceed (NTP) • Building “Dried-in”

  41. CE 405 - SCHEDULING Examples of Milestones? • Notice to Proceed (NTP) • Building “Dried-in” • Contract Substantial Completion • Work on all Activities has progressed to the point that the Project could be used for its intended purpose • Liquidated Damages not assessed

  42. CE 405 - SCHEDULING Examples of Milestones? • Notice to Proceed (NTP) • Building “Dried-in” • Contract Substantial Completion • Project Complete • The Owner has accepted the work and will make Final Payment

  43. CE 405 - SCHEDULING Activity-On-Node (AON) Networks: • AON Networks are normally displayed as “boxes” connected with “lines”. The “lines” indicate some form of relationship between the “boxes” at each end.

  44. Red logic boxes = Critical Path • “X-ed” boxes means Activity is complete.

  45. CE 405 - SCHEDULING Primavera software is based on the generic Precedence Diagramming Method (PDM).

  46. CE 405 - SCHEDULING Activity-On-Node (AON) Networks: • By definition – preceding [Predecessor] Activities in an AON network must Finish before the following [Successor] Activity can Start. This is described as a “Finish-to-Start” relationship.

  47. CE 405 - SCHEDULING REVIEW: What were the four types of Activity Relationships that we covered during the Bar Chart discussion?

  48. CE 405 - SCHEDULING Four types of Activity Relationships: • Physical • Safety • Resource • Preferential

  49. CE 405 - SCHEDULING What is a Constraint in a Scheduling context?

  50. CE 405 - SCHEDULING What is a Constraint in a Scheduling context? • Something that controls the accomplishment of an Activity

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