Rolling Wave Technique

Ulysses,
in the long large projects you have no other choice.
In smaller projects (like high rise construction) it is reasonable.

Hi Vlad,
Long time didnt meet your post thread, Anyway could you brief me little bit about this technique... Maybe its the same with mine but different definition, interms of words.

p.s.Try to figure out... is it like wave. ha ha
nothing offended just lefted behind by technology.

Greetings one and all,
In regard to the rolling wave planning technique, I am in the throws of finalising a technical paper on the subject of resource planning in Primavera enterprise. The theory is based on rolling wave technique and I will be more than happy to send any of you a copy when I’m all done, hopefully in a week or two.

If you would like to see a copy just send me your e-mail address to andrewtdick@optusnet.com.au

Andy

Hi Raja!
Rolling wave means that you have the detailed schedule for the nearest period and not that detailed for the rest of the project. This period shall be defined in advance and kept during the project. If for an example you decided that the period for detailed planning shall be 3 months then you shall always have the detailed schedule for 3 months ahead of you. If 1st month is behind then the detailed schedule includes 4th month.
In high rise construction we found through work simulation that deviations in the schedule influence the schedules of the next three floors, on the 4th floor the difference is almost absent. So we decided that there is a need for the detailed schedule for the next 4 floors and after that it is enough to schedule floors as activities.
Hi Andrew!
Thank you for the suggestion. I would like to read your paper though we use different software.
My E-mail: spider@mail.cnt.ru
Vladimir

Thanks Vlad,
now i understand, its seems like a window where we should do such detail activities for the interfacing activities which the work have to control closely to meet the date, I would say if the work could not finish, then other work will get the impact until cant move for installation.

Hi andrew,
good thing to share the ideas, Sent a copy to miharbiz@yahoo.com.

Thanks in advance.

Hi Guys,

I did encounter rolling waves techniques.

Vlad,

The theory behind Rolling waves is great.

In my experience as project management consultant, the rolling waves degenirated into just plain three months look-ahead schedule filtered from primavera DD+3M. Also to that effect, the planning and control did not make any difference.

The contractor find it hard to reconcile what is happening at site compared to his plans: rolling plans (wave) three months.

Vlad, I thank you for your enlightenment. I will ensure rolling waves techniques will be implemented and monitored in all project I manage, starting today base on your concept.

Hi Andrew,

I’m glad if you share your ideas, please sent me a copy: charlieorbe@gmail.com.

Cheersa and I thank you in advance.

Joseph

Thank you, guys!
I am glad to be useful.
Regards,
Vladimir

Hi Vlad,

Need some help/ idea, If only 3-4 months to breakdown the activities and the other at high level , How do we know the critical path.

Hi Ulysses,
high level schedule (of the next phases) is still project schedule with the critical path, etc. It has fewer details, usually without resource assignments.
Usually resource levelling is applied only for the detailed part of the schedule, but financial constraints are applied to the whole schedule.
So resource critical path is calculated for the detailed part and classical critical path for the rest of the schedule.
Vladimir

I will suggest an example:
for the nearest 4 floors each floor will consist of external walls, internal walls, columns, staircases, brick works, floors work packages.
Internal wall work package will consist of Reinforcement, formworks installation, concreting, curing and framework striking. Other work packages will be decribed in similar details with assigned resources, materials, costs.
Starting with the 5th floor from the current floors will be presented as activities linked by Start-Start dependency with the lag. The lag size is based on the detailed schedule results. Materials and costs are assigned to the floor. After current floor will be finished 5th floor will replaced by the small project (we call it typical fragnet) that describes floor construction in details (as described above).

This technique ,I guess it can be done only by using software, using manual calculation, im sure your will lead not to heaven.

Yes, I described the technique that is easy with the use of the software.
The manual scheduling is hard in any case. But in this case too it is reasonable to create predefined fragnets and add them to the schedule when necessary.

In Simple terms, I will put "Rolling Wave Planning" in this fashion:

It is a form of progressive elaboration planning where the work to be accomplished in the near term (2-3 months) is planned in detail at a low level of WBS, while work far in teh future is planned for WBS components that are at a relatively high level of WBS.

The work to be performed within another one or two reporting periods in the near future is planned in detail as work is being completed during the current period.

Cheers,

Raviraj

Is this type of approached effective? How many in the construction industry at present is using this method?, maybe only few or none of them. I think this approach is in its infancy

Hi
for my experience it is a very commonly practiced technique. E.g. during an engineering phase you have an idea of testing - parameters, measures, how exact it must be - but no exact schedule. This you’ll create later. It’s noted as a standard in the PMBoK (Project Management Body of Knowledge from PMI) too.
Regards
Dieter

For me, as Dieter said, it is a very commonly practiced technique.

Its only now (May be few years before), that we have given name to this methodology of working. Its there in PMBOK too.

Cheers,

Raviraj

Hello everybody,

I believe this technique is used under different names. For a contractor, Rolling Wave Technique is needed especially in fast track projects. It is used in order to keep other departments (construction, engineering & procurement) alerted about the coming new activities hence the required related resources in a determined interval of time.

Awaiting your comments

Before applying this technique; be sure that the schedule specs. alows you to do so, in such case you will not be technically rejected

This is a detailed two-to-three month look ahead program, so that your team can manage projects on time and make sure all the resources available including tertiary items.

Are V suppose to give this kind of schedule to Client. I won’t? What do you suggest guys?

I would agree Raviraj. We could go on to any level of
detailing in our schedules but of course we wouldnt want
to give the Engineer or Client details to that extent. I
dont think it would be necessary too as such a level of
detailing would be for internal work front estalishments
and detailed resource planning. The higher levels with
flexibilities incorporated should be for Cl.14 monitoring.

Vlad, that was a nice example of the rolling wave technique
applied to high rise. However, in case of horizontal wide-
area projects like process plants, it is very difficult
to establish fragnets repeatedly as each process unit could
be unique and completely different from the others. This
would involve detailed study of every unit, individual
unique method statements of construction, thereby leading
to detailed scheduling. Such a level, would in any case be
difficult to achieve in the initial submissions. How do we
then establish the sufficient level of detailing in such
cases ?

Happy Planning folks.....

Ramesh

Thanks Ramesh,

But I think, process plants are not example of horizontal wide-area projects, as each process plant will definitely be a unique project in itself.

Detailed planning would be required for each process plant, as quantities and resources will vary widely with each process unit.

Fragnets can be used efficiently on projects like High-rise building (Vertical spread) or on horizontal spread projects like pipeline or highway works with repeated works.

Rolling wave can be used on process plants once engineering is finished and drawings are released FOR CONSTRUCTION and then & then only it is possible for detailed planning. Control accounts for WBS can be developed once detailed planning is finished.

Maybe senior persons like VLAD can throw some more light on this.

Cheers,

Raviraj A Bhedase

Thanks Raviraj,

Would like to clarify that when I said horizontal I wanted
to emphasise on the fact that as opposed to vertical
construction like high rise, the sequence of overall
construction in such plants is not straight forward or
rigid. For example, in high rise or any building, one
has to go floor by floor one after the previous in a
continuous fashion. Whereas, in such plant constructions,
there could many possibilities of unit sequence assuming
of course, that the complete possession of SITE is
available. If there is sequential handover of SITE from
client, then at least that would govern the construction
sequence by contractor. Otherwise, options are many. Then,
I would imagine, it would be more governed by unit equipment
deliveries and furthermore, cash flow profile. Though of
course, Civil works would still have lots of flexibility
assuming there arent many resource constraints.

However, its possible that having adopted such an approach,
it still could lead to quite a few changes in actual
construction as units which havent been planned will have
to be approached for construction as delays in planned
units due to design issues, approval issues, could happen.
(Here I particularly mean such reasons of delay which are
outside the controls of the Contractor)
This could then lead to resource imbalance if resources
are very tightly planned and are not ample. How do we
then tackle the situation in such cases ? Could this be
a case for a claim of any sort, time or money ?

All the above could reflect as a disagreement between the
main higher level programme prepared first for submission
and the rolling wave that occurs at current situation. How
do we tackle this ?

Vlad, could you also please share your view on this ?

Cheers & Regards,

Ramesh

Hi Ramesh!
You suggested very interesting discussion topic.
You are right – in high rise construction and linear (roads, pipelines) construction the sequence of work is somehow defined (the choice is limited). The same is true for shipbuilding and similar projects. In site construction the works can be done in parallel in many places simultaneously.
There are two options:
1) To create the detailed model from the very beginning and to calculate project schedule taking into account resource, financial and supply constraints. This approach is hard and time consuming.
2) To create high level model, not very detailed, but with cost and duration estimates of its elements. This model can be used for determining the sequence of construction basing on the program financial limitations. If the sequence is determined then the nearest part of the project (let’s say 6 months duration) shall be developed in more details to consider resource restrictions. Now you shall compare initial estimations with the detailed. If the difference is large I recommend to reconsider time and cost estimations in the initial schedule in the same proportion.
Now you can apply rolling wave technique.

Actually we suggest also to simulate risks and to add contingency reserves to the scheduled dates and costs.

Fragnet libraries are applicable to the site construction too if they were created on the low level (external wall, internal wall, column, floor, etc. for different types of construction – bricks, concrete, etc.).

Responsibilities for the project delays due to external issues (like design, approvals, supplies delays) shall be specially set in the contract. At least the delays of such events (that shall be included in the contractual schedule!!!) shall lead to the corresponding delays of the target dates. But each additional day on site costs money for the contractor, so it is reasonable to recover these additional expenses from the guilty side. It is not applicable to the delays caused by external events that do not depend on the client (weather conditions, government actions, etc.).
Regards,
Vladimir

Hi Vlad,

Thanks. I am glad that you understood my point of view very
well. I couldnt agree more with you on the point of risk
simulations and adding contingency reserves. One clear
example of that could be seemingly unreasonable durations
for certain activities. But when it comes to practical
execution at site, we could realise that the durations
were not actually unreasonable, in fact, they prove to
be just enough. The hard part in such cases is to convince
the Engineer and Client of such time frames because they
would normally relate the required time frame straightaway
with the associated quantities. But the fact is that when
the schedule is at a higher level, we have to disassociate,
for many cases, the estimated quantum of work from the
estimate of time required, incorporate our risk factors &
contingencies and then arrive at the final estimate.

Now, when the breaking down of these levels is done, we
may find that adjustments may be required. Now the problem
here is that we would have already submitted this higher
level base to the Engineer/Client, who then go strictly by
that.

I personally feel that the best solution for all this would
be to go for bottom-up planning rather than top-down planning as
then we could have everything in detail which could be rolled
up at any higher levels required. Because, in Top-down approach,
this discrepancy in methodology is bound to surface when we do
further detailing. Whereas, in Bottom-up, the detailing is
already done and can be rolled up which saves all the time
of further creation of Rolling waves.

But then, as you rightly put Vlad, this could be very time
consuming and moreover, it requires much deeper insight and
study of large projects right from the beginning which no
one is ready for, all the pressure is usually on the planner
to know everything, or at least, most of the things.
So, probably the only good thing for planners would be to get
more than the 28 days allowed as per Contract conditions to
prepare the initial Baseline, at least for large projects
which span for 2 to 3 years....:-).
Lets say, maybe a formula based determination like 5% of the
duration of the project in days or 28 days, whichever is higher..:-).

Happy Planning folks....

Ramesh

Ramesh,
I think that it is not reasonable to create very detailed schedule for the project that lasts many years.
I suggested to adjust high level schedule basing on the comparison between high level and detailed schedules of the project nearest part. Usually the proportion for duration and costs adjustments is very close for different parts of the same project.
Calculating contingency reserves is better but it is not easy to convince that these reserves shall be included in the contract.
Regards,
Vladimir

Hi Ramesh / Vlad,

Andrew Dick has written a fantastic paper on Resource allocatin in P3. Check his previous post in the same thread.

Good explanation of Rolling Wave Planning & Planning Packages (Control Accounts)

You can request him for the papers.

Cheers,

Raviraj A Bhedase

hi all
please would you send me a copy
my mail is dinaelghandoor@hotmail.com