Who Creates the Schedule?
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? The General Contractor (GC) must create the detailed schedule, specifically for the construction phase* :
A. Usually used for bidding or negotiation
B. An approved copy (by the owner) will be the “Baseline†as a reference to measure performance
C. It is a roadmap for how the contractor intends to build the project.
D. It has to be updated periodically to reflect reality and implement changes.
E. It is a legal document that may be used for or against you! * except in the case of “design-build†contracts
Steps for Creating a CPM Schedule?
1. Breakdown the project into activities
2. Determine activities’ durations
3. Define logical relationships (interdependencies)
4. Draw the network, and perform CPM calculations
5. Optional: Resource/cost-load the project
6. Review and analyze the schedule
7. Implement the schedule
8. Monitor and update the schedule
9. Closing out: database and feedback
Simplify the Schedule, Tip #1: Accurate Schedule
* Be accurate and systematic in creating the schedule
? Make it easy for you or anyone else to review any part
? The schedule is a legal document that may be used in the court of law later
? Make sure it is done by a professional!
? Do not let greed, over-confidence, or the owner’s pressure make you go against your “educated common-senseâ€.
? Avoid the “We’ll correct it as we move on†syndrome
* “Anything you say, may and will be used against you!â€
* Simplify the Schedule, Tip #2: The Tools
? Pick the right software program
? It does not have to be the most expensive or even the most advances one
? Remember: Excel is a great software but it is NOT a scheduling software ?
? Know the defaults and rules
? Know the functionalities and tricks ? Challenge the software and question tech support: It may not be perfect!
? You should be driving the computer, not the other way around!
? Sometimes, it’s the owner’s choice, not yours!
Simplify the Schedule, Tip #3: WBS
? The project breakdown structure:
? Every activity has to be:
1. Well-defined
2. Easily measurable, using one unit only
3. Controllable
4. Performed by one crew (unless…),
? Milestones are for important events only
? The project has 1000’s of activities? So what?
Confidence Level Versus Level of Detail?
Confidence Level Versus Level of Detail?
Simplify the Schedule, Tip #4: Activity Durations
? Activity durations:
1. Where did you get your productivity numbers from?
2. Have you applied proper adjustments?
3. “Lean durationâ€: Leave time contingency away from activities and under the control of the PM
4. Do not include “non-work gapsâ€.
? An “Obtain Permit†activity should not be a 60-day activity. It can be a milestone with 60-day lag (or one-day activity with 59-day lag)?
Simplify the Schedule, Tip #4: Activity Durations
? Activity durations:
5. Remember that activities consume time, resources, and budget
? Waiting for concrete or asphalt to cure (without effort) is NOT an activity
6. Do not include two or more segments with different production rates within the same activity
7. If you are using “Day†as the time unit, round up duration to whole numbers.
? Do not use fractions of the day! 8. If the duration is large (for example, 40 days), divide it based on geometric criteria.
? For excavation, you can divide it by grid. For a CMU wall, you can divide it by segment.
Repercussions of Inaccurate Durations
? Always check production rates against project conditions
? Impact on succeeding activities
? Delayed crews
? Wasted money
? Shortage of materials / crews (if actual date is earlier)
? Possible problems with cash flow
? Disrupted plans and chaos
? Warning: don’t accept unrealistic expectations!
? If you over-promise, you will under-deliver!??
Simplify the Schedule, Tip #5: The Logic
? The logic (activities interdependencies):
1. Use only / mostly F-S relationships.
? Most situations with S-S, F-F, or combination relationships can be re-drawn using F-S relationships only.
2. Lags are okay: They represent time period with no work (no resources, no budget). ? Avoid using “Leadsâ€, i.e. negative lags
? Lags are different in type!
3. Remember “external activitiesâ€!
Splitting Activities to Simplify?
The continuous lag?
The continuous lag?
The encased (enclosed) lag?
The encased (enclosed) lag?
Simplify the Schedule, Tip #6: Imposed Constraints
Simplify the Schedule, Tip #7:
Activities Attributes
? Activities attributes:
1. The ID: The pattern, the default “jump†? ABC2200, ABC2210, ABC2220,
2. The title / description: What and where
3. The codes: Along with software tools such as “Group and Sort†and “Filterâ€
? Using codes is a great way to group and select activities.
? Do you have a code table (legend)??
Simplify the Schedule, Tip #8: Time vs. Cost
? When the owner “cracks the whip†on you to finish earlier, lay down the options: Time versus cost
? You want the project to finish earlier? It is possible (within limits) but at an additional cost!?
Simplify the Schedule, Tip #9: Resources
? Resource / Cost Loading:
? Create and classify resources info in the software program: Category, description, production rate, unit, cost, availability and restrictions, …
? It may not be practical or even feasible to resource-load subcontracted work. Cost-loading is possible and important though.
? Resource leveling is a great idea, but do you have to level all your resources?
? Many contractors don’t do resource leveling. Fine, but track your major resources.
? There is no such thing as a project with unlimited resources?
Simplify the Schedule, Tip #10: Schedule Updating
? Make sure:
1. There is a system and protocol for schedule updating.
2. The interval is defined and respected.
3. It is done on time and according to the policy.
4. It is taken seriously: the process and the report.
5. “Exceptional†updates are labeled and stored in a different way
Simplify the Schedule, Tip #11: Reporting
? Reporting: There is no such thing as “one size fits allâ€!
? Control the type, amount, and organization of the information
? Speak at the right technical level of the other side
? Too much information is not good!
? In e-reports, use the hyperlink function to allow user to go to the details
? The spotlight concept: show only what you like to focus on.
? Use software program tools: Summarization, Group’N Sort, Filter,…
? External versus internal reporting
? Speed and efficiency of conveying information
Simplify the Schedule, Tip #12: Schedule Risk Management
? How do you account for risks in the project?
? At the activity level:
? Example, an excavation activity, and you experienced unforeseen conditions, or the excavator blade broke down
? At a group of activities level:
? Example: A truck delivering items for several activities broke down
? At the entire project level:
? Example: hurricane or labor strike… or COVID-19
? Does the risk impact all activities at the same level?
? How much time contingency have you allocated? How do you manage it??
Simplify the Schedule, Tip #13: Who Owns the Float?
? This is the billion dollar question ?
? Float ownership is one of the most controversial issues, technically and legally
? The best approach is to keep it under the GC’s ownership, but the owner has the responsibility of reviewing and approving the baseline schedule including durations and logic.
? If an unexpected delay happens, the owner can see if the delay can be absorbed by the float, and if an extension is justified.
Simplify the Schedule, Tip #14: Final Comment
? The effective schedule has two legs:
? Good preparation before start
? Good follow-up (updating) while in progress
? You cannot walk with one leg!?
*Author : Saleh Mubarak