Rolling Wave Technique

hi all

please would you send me a copy

my mail is [email protected]

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

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 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

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

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

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

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

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?

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

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

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

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

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.

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).

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

Thank you, guys!

I am glad to be useful.

Regards,

Vladimir

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: [email protected].



Cheersa and I thank you in advance.



Joseph

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 [email protected].



Thanks in advance.

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: [email protected]

Vladimir

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 [email protected]



Andy

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.

Ulysses,

in the long large projects you have no other choice.

In smaller projects (like high rise construction) it is reasonable.