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Transcript of Jorge Alberch Page 1 Planning and Scheduling Being busy does not always mean real work. The object...
Jorge Alberchwww.projectcontrolsinternational.com
Page 1
Planning and Scheduling
Being busy does not always mean real work. The object of all work is production or accomplishment and to either of these ends there must be forethought, system, planning,
intelligence, and honest purpose, as well as perspiration. Seeming to do is not doing.Thomas A. Edison
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Overview – Or Why Should We Plan?
• The answer to the question “why should we plan” is very simply and correctly
stated by Alan Lakein as follows: “Failing to plan is planning to fail”.
• When everything goes well, one might be tempted to
question the value of planning and scheduling. However, projects do not always
go well, and when they do go sour, they can do so in a spectacular way. A project
gone wrong can undo the success and hard work put into many projects.
• You may choose to ignore the planning aspects of the project… but you do so at
your own peril. Do you make important decisions in your life without forethought?
Then why run the project differently?
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Overview – What is Planning?
• Planning quite simply is the project execution’s road map.
• If driving from one city to another, we make use of
maps, then why would we shy away from doing likewise
when it comes to outlaying the plan for the project? If the
project is later “lost” in the execution due to e.g. materials not at site
when required, was there a correct plan in place? Lack of planning makes
for a potentially disastrous project with cost and time overruns.
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What Is Planning vs. What Is Scheduling?
While both terms are used loosely to be synonymous, and hence to some
extent interchangeable, a more rigid concept of these two terms is as
follows:
1. Planning is the overall high level plan or road map of the project’s
execution plan. It focuses on the big picture, and tries to answer in an
encompassing manner questions such as when, how, what, where and
why.
2. Scheduling is the simply the technical mechanics of putting the plan
on paper, typically by way of a Critical Path Method (CPM) schedule
with activities tied up with each other with relationships and
constraints.
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What Makes for a Planner?
• Think of a planner as a chauffer/ taxi driver. The Project Manager/
Construction Manager/ Team Leader wants to go from point “A” to point “B”
and has the resources and executive power to do so.
• However, they might not know (or have the available time to carefully study
and analyze) which roads to take, which ones to avoid, and how long it’ll take.
• Hence the planner must support all incumbent parties and coordinate as
necessary, to ensure the project flows smoothly according to plan.
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Heterodox Planning
“I would rather have a good plan today
than a perfect plan two weeks from now.”
General Patton (1885-1945)
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Heterodox Planning
Earlier chart shows level of influence of the project’s life’s span. One can greatly
influence the outcome of project at the early stages, however as the project
progresses one’s level of influence diminishes.
Hence risks, constraints, deficiencies must be identified and corrected/ acted up
early in the project, otherwise later in the project these are much more difficult,
and in some cases impossible to correct, mitigate or ameliorate.
Upfront planning – and the corresponding resulting actions – are necessary for a
successful project.
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Heterodox Planning
“Planning is not only simple statistical work but
effective coordination and pushing forward.”
Department Manager
“I’ve ignored the planners for the last six months.
I simply have no use fore them.”
Team Leader
Above are a couple of real-life quotes, which should give you some food for
thought. First, planning is not just a paper exercise, or quoting “simple statistical
work”. Furthermore for planning to add value, it must generate/ result in some
action being taken. The second quote is actually very typical of those in charge of
executing the project. Again, planning must add value and effective and
productive communication with the incumbent parties is absolutely paramount. To
repeat: there must be active and engaging dialogue with the key stakeholders,
otherwise some people might feel planners are of “no use”.
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Work Breakdown Structure
1. The WBS is a basic project management tool which defines the project
along activity levels that can be clearly identified, managed and
controlled.
2. An adequate amount of detail is critical. Too much, and it can be
overwhelming. Too little, and it defeats it’s purpose. One must
carefully think how to break the scope of work into meaningful work
packages, both from a planning and cost control perspective.
3. Future additional value can be obtained by creating historical
databases, with normalized data for productivity and costs.
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Schedule WBS
1. Milestone Summary
2. Engineering
3. Procurement
4. Construction
5. Commissioning
One of the first thing to look at when creating a schedule is the Work
Breakdown Structure (WBS). Typically the WBS “level 01” would consist of the
following WBS codes:
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Schedule WBS – Additional Detail
Example of how *not* to structure a project follows below. Let’s say that we
have an overhead transmission line, supported across 25 towers. Then it’s
decided that all the tower foundation construction and all the tower erection
activities are to be lumped into “Tower Foundations no. 01 to no. 25” and
“Tower Erections no. 01 to no. 25”.
Question: Why is this wrong?
Why By lumping all these similar activities
together we loose granularity, the ability
to see the progress for each tower.
A good Work Breakdown Structure is very important: it allows for
greater clarity as to project progress and costs (planned and actual).
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Schedule WBS – Additional Detail
Example of how to better structure a project follows below. In this instance
each tower is clearly defined and the progress for it can be easily measured/
observed.
Question: Why is this better than the
earlier example?
In this case we have much improved
granularity, with the additional detail.
How should one develop the WBS? One must think about the amount
of detail that is necessary, and show it in a clear fashion.
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Schedule Activity Relationship Types
The are 4 relationship types:
1. Finish to Start (FS)
• When A finishes, then B can start. This is the most
common activity relationship.
2. Start to Start (SS)
• When A starts, B can start.
A1000
Activity A
Day 01 Day 05
5 A1010
Activity B
Day 06 Day 07
2
A1000
Activity A
Day 01 Day 05
5
A1010
Activity B
Day 01 Day 02
2
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Schedule Activity Relationship Types
3. Finish to Finish (FF)
• When A finishes, B can finish.
4. Start to Finish (SF)
• When A starts, B can finish.
A1000
Activity A
Day 01 Day 05
5
A1010
Activity B
Day 04 Day 05
2
A1000
Activity A
Day 01 Day 05
5
A1010
Activity B
Day 01 Day 02
2
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Schedule Activity Relationship Types – Tip!
It is recommended to avoid convoluted logic. Wherever possible keep
relationships to Finish to Start (FS). Also avoid the use of lags, and
only use them when it is warranted to do so.
Note! Convoluted logic and excessive use of lags can be indicative of
lack of granularity. Often times creating additional activities can
reduce the need of complex logic and lags. Example below.
A1000
Concrete pouring
Day 01 Day 05
5 A1010
Equipment placing
Day 20 Day 20
1FS+14
A1000
Concrete pouring
Day 01 Day 05
5 A1005
Concrete curing
Day 06 Day 19
14FS
A1010
Equipment placing
Day 20 Day 20
1FS
Figure 1. Use of lag (14 days for concrete curing).
Figure 2. By adding the “Concrete Curing” activity, there’s no longer a need to have a lag. Also the reader can
better understand why the equipment cannot be placed on the 6th day.
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Schedule Activity Durations
It is common to see schedules containing many activities with excessively
long durations. This is indicative of a potential lack of granularity, whereas
the activity with the long duration should be split into multiple activities and
with shorter durations.
Tip! As a rule of thumb no activity should be longer than about 2 reporting
periods. Since these are usually weekly, then generally, no activity should
have an original duration of longer than 14 days.
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Progressing a Schedule - Warning
Once the project’s baseline schedule is created, it must be progressed.
Typically this will be done on a weekly basis.
Warning! Common pitfall: Very often a copy of the each week’s progressed
schedule (native file) is not kept by the planner/ scheduler. This is a big
mistake as the native file might be needed in the future for analysis and to
support claims. Therefore native file copies (the .mpp or .xer files) copies for
the baseline and each progressed schedule must be kept! You may ignore
the warning at your own peril!
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Progressing a Schedule – Typical Settings
For most applications, while scheduling with Primavera P6, when progressing
a schedule it is recommended to use the select the “Use Expected Finish
Dates” and “Progress Override”.
Note: Ideally each activity’s remaining duration would be manually re-
evaluated, however it’s often convenient to use “Expected Finish Dates”
(however the date must be entered in the activity details beforehand).
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The Schedule Critical Path
The schedule’s critical path identifies the activities that are most critical,
which dictate the project’s final completion. A delay in the start or completion
of these activities will impact the completion date, in contrast with other
“non-critical” activities with available positive “total float” which can be
delayed without impact to the overall completion date.
At this point, let us formally define some important terms related to the
schedule critical path.
Critical path: It is the chain of activities with the smallest total float value. A
delay in any of these will directly impact the project completion.
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The Schedule Critical Path
Total Float: It is the activity’s LF – EF (Late Finish – Early Finish); or LS – ES.
The total float shows how much an activity can be delayed before it impacts
the completion date of the project.
Note: Total float is shared. If an chain of activities, an activity is delayed, the
subsequent activities will have reduced total floats.
Free Float: It is the activity’s EF – ES of the subsequent activity minus 1
(Early Finish – Early Start of subsequent activity - 1).
Note: Free float is unique to an activity. This is how much an activity can be
delayed before impacting the subsequent activity.
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First one must ask what is the purpose of the schedule: is it a summary
schedule or a fully detailed schedule. Also the complexity of quantity of
the scope of work being scheduled will obviously also determine the
number of activities.
However, as a general rule, a detailed schedule could very well have between
1,000 and 3,000 activities (or many more as necessary).
Note: A schedule with only 100 activities or even a couple hundred activities, is
not a detailed schedule (unless the scope of works is very simple and
limited). A small number of activities is indicative of lack of granularity in
the schedule.
How Many Activities Should the Schedule Have?
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Schedule Checklist
How to quickly check the quality of a given schedule? What common pitfalls
should one avoid when scheduling?
1. Incomplete logic. This is the very first thing that should be looked at. All
activities with the exception of the first and last should have a predecessor and
successor. A schedule that has activities without predecessors or successors is
indicative of a poor quality schedule.
2. Convoluted logic. Schedule logic for the most part should be fairly
straightforward and flow harmoniously throughout with preferably finish to start
(FS) relationships. The over use of lags, either positive or negative, signals poor
logic, lack of intermediate defining activities or activities artificially shifted to
meet certain dates.
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Schedule Checklist
3. Activity durations. Another item to watch out for. Often times one will
encounter schedules with unnaturally long activity durations. Activities where
possible as a rough rule of thumb should be no longer than the reporting
period. Schedules which contain numerous instances of activities with
relatively long durations are indicative of lack of detail. These activities should
be broken into smaller activities with the corresponding logic.
4. Calendar. It’s somewhat amusing in a way to find a schedule, especially
one that’s been used for some time, with either the wrong project calendar
altogether or with some of the activities using incorrectly differing calendars.
For example some activities using a 5 day calendar while others using a 7 day
calendar.
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5. WBS. Ideally the cost breakdown and schedule breakdown should follow
the same structure. It is important to note though that the schedule will often
times have more detail than the cost breakdown, meaning that there will not
be a one to one relationship between each cost activity and schedule activity.
Rather it’ll follow a one to many relationship. The important thing is that both
breakdown structures at some level are identical.
Planning is bringing the future into the present
so that you can do something about it now.
Alan Lakein, Author
Schedule Checklist
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Document Control/ Basis of Schedule
1. Schedule purpose2. Project’s Scope of Work3. Period of Performance 4. Critical Path Narrative5. Key Dates6. Constraints
• A schedule should always include written documentation on how it was
developed including assumptions, constrains, risks and other notes of
interest. A typical basis of schedule could have the following sections:
8. Execution Plan9. Resources available (Labor,
Material and Equipment)9. Risks10. Project unique factors11. Other considerations
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Extensions of Time, Claims and Disputes
Do you have an approved Critical Path Method (CPM)
baseline schedule? Have you progressed your schedule at
regular intervals (e.g. weekly)? Have you prepared accurate
and detailed daily progress reports?
If the answer in “no” to any of the above, you’re case is practically lost, and
unsubstantiable. Hence the importance of due diligence as it relates to
good solid maintained scheduling and reporting systems in place. As a
Contractor a good Project Controls section pays off by itself, if just to
handle Change Orders, Extensions of Time, Claims and Disputes.
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The Cost of Changes
Changes to execution plan are a reality. These changes can arise from a variety of
sources, however these changes can impact productivity and have a cost impact.
•Overhead costs can be impacted, due to additional administrative work and
supporting facilities.
•Need to hire additional manpower, or remobilize equipment, however this might
impact productivity or bring additional costs.
•Work low interruption, hence lowering productivity.
•Working space congestion, with multiple work crews in same work location hence
impacting productivity.
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The Cost of Changes
•Increase overtime, with the consequent additional overtime premiums and
reduced productivity arising from worker fatigue.
•Increased possibility of errors arising from the change in plan, hence confusion,
lost working time, and re-work as common side effects.
•Chain/ domino effect impact on subsequent dependent activities. Activities that
previously had float might now become critical with all sorts of unforeseen cause
and effects rippling through the entire schedule.
Note! However, claiming for many of these cost/ time extensions aspects of the a
Change Order is extremely difficult, unless complete and meticulously clear data is
presented as part of the claim.
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Tips – Printing a Schedule
Do you want read a 50+ page printed schedule? I would think not. Even if you
have the patience for this, believe me, the Construction Manager/ Team
Leader/ Superintendent does not.
Therefore it’s highly recommended to print in portrait (an *not* in landscape).
Also it’s ok to minimize the bar chart area as necessary to make the
schedule fit, after all, the important information like start and
completion will already be listed in the columns on the left.
Tip: limit a printed schedule to less than 12 pages where possible.
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Tips – Communicating a Schedule
It matters very *little* if you put together a fabulous schedule, if the
incumbent parties fail to take an interest in it. It’s like an writer whose
books remain unread.
Therefore, active communication by the planner to the incumbent parties is
absolutely critical. The planner must build a rapport with the relevant
people and communicate effectively the main aspects of the schedule,
such as the critical path, constraints, concerns and schedule risks.
Tip: A good communicator is more important that a good scheduler!
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Tips – The Schedule is *Not* Real
That’s correct. The schedule is *not* real. It is *not* an exact representation of
reality, but rather a very simplified – and imperfect – representation. It is
not an exact science, but to some extent an art.
However used correctly, it’s a very useful tool to analyse
the execution plan, criticalities, concerns and risks. It’s also
very helpful in forcing one to think about these and as a medium of
communication.
Tip: Therefore the scheduler should not get lost in the finer details, but
maintain a holistic view. One should avoid not being able to see the
forest for the trees.
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Tips – Why your schedule will be late
Surprise! At least 50% of the times your schedule will be late.
How can that be? Easy: The schedule is deterministic with activities’
durations being averages. For example if “travel to work” was an
activity, it might take 25 minutes in a good day, 35 minutes on average
or 60 minutes in a bad day with heavy rain or snow. So for this activity
(assuming mean and median to be the same) 50% of the time you’ll
arrive to work early, and 50% of the time late.
Tip! Ensure some contingency. You can also run a PERT analysis if you have
the software. But the important thing is to be mindful of duration
averages, and the need to have some extra leg room in your schedule.
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Planning and Scheduling Wrap-Up
Failing to plan is planning to fail.
Alan Lakein – Author
Final note: Planning is important. A correct CPM baseline schedule,
progressed on a periodic basis to substantiate your claims or project
status is essential. However, a healthy dose of skepticism will cure
you of being either too optimistic or pessimistic, and keep your mind
open to an infinite number of possibilities. Plan and act accordingly,
but never in blind faith. After all: Life is a box full of chocolates.
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Project Knowledge = Project Success
This presentation is a work in progress. I would love to hear from you
with suggestions, additions and comments.
You can contact me at:
www.projectcontrolsinternational.com