Thanks Mike; this clarifies the difference between "Impacted as Planned" and "Time Impact Analysis".

We try to implement the "Impacted as Planned"; whenever possible, as most of the circumstances and arguments will be fresh in all parties minds. (It is a MUST in case of nec3).

Thanks and regards,

Hello,

with my humble knowledge in this field; Time Impact Analysis is mainly used to "forecast" the effects of events which occured on the past; on the future completion of the project.

For example; u r in the middle of a project. One event occured (let’s say climate condition); which caused the site to stop working for 2 days (note: the event occured already). Time Impact Analysis is used to "forecast" the impact on the completion date.

As-Built (despite I never used it); however I presume it is used in case you cannot update the program due to the fact that the relations in the program are not matching the way the construction took place. In this case; u cannot use Time Impact Analysis, specially if the activities are completed.

Under nec3; with each update; u change the relations to realistic ones (actually, u r revising the baseline with each update; and supersedes the previous one).

Hi Ethel

While Andrew is away sorting out your contractual problems you asked what method of analysis to use with your As Built Data.

I notice you are using P6 - I have no knowledge of this system but I do beleive you can cut and paste dates between spreadsheets - this is big time saver so make use of it.

For the work in progress - where there is no As Built - use an Impacted as Planned method where the events are inserted into the programme and linked up to the affected activity and the programme rescheduled.

You can then compare Planned v Impacted and demonstrate the likely effect.

Make sure that the event date is the "Impact Date" which allows for procurement and mobilisation of any changed work.

For the work already completed - a Time Impact Analysis is required.

Again you schedule your events with the Impact Date into chronoligical order.

Impact the first one into your programme and see what happens - there will be one of four effects.

1. The critical path will not change but some float may have been used up.
2. The critical path does change but the affected activity does not reach the As Built zone - in which case something else delayed the work so either do some more research or accept that it was the Contractors problem.
3. The impacted eactivity corresponds pretty well with the As Built bar which means that you have "reasonably demonstrated" cause and effect - this is the least likely outcome.
4. The impacted activity overshoots the As Built which means that the Contractor did not follow the programme - if you know what was done differently then replicate the changes - if you do not know then you must use your experience to make whatever changes would be available to the contractor and use the most plausible ones first until your Planned corresponds with the As Built.

Now continue with every other event making a detailed record of what you have done and what the results were so that someone else can replicate your work.

Good luck.

Mike Testro

Oh, would be that one, the situation has just become a little more complicated, not just saying that for the hell of it, but early warnings and all, retrospective claiming of an eot was not ever the intention of that contract.

More details please.
(you can send me a private message if you prefer)

Thanks Andrew, but just to mention that my project is still on and not in the past although the events we want to claim on is in the past.

Cheers

Ethel

Ethel,

You are composing an as built programme – everything is in the past so the data date is the very last date in your programme. You will never reschedule this programme, it is a statement of what actually happened on the project. Everything will be to the left hand side of the data line.

You should only be using actual start and actual finish dates, (or possibly actual durations in conjunction with actual starts), and as Mike pointed out, do not try and insert logic links.

Hi Ethel

Regarding As Built Programmes it all depends on the type of software you are using - since you are a railway specialist I suspect it is P3 which is a pity as it will take 3 times longer than if you use PowerProject.

Don’t start on your barchart until you have all the data on a spreadsheet.

This should comprise a column with the activity references and another with dates - percentages - comments etc.

Once you have a complete spreadsheet it can be sorted into activity references and date order.

Save your baseline programme into a different file and set up a "target" programme for your original durations.

Delete ALL logic links

Now adjust your planned durations to actual start and actual finishing dates. If there are non working gaps then either split the bars or draw multiple bars under a summary.

You now have an As Built Programme.

What you do with it is another matter.

In PowerProject I would set up another "target" programme on the As Built basis and then close the file without saving the changes thus I have a planned programme overlaying the As Built.

This is ideal for a Time Impact Analysis or if it is subcontract work an As Planned v As Built analysis.

You cannot do this in P3 so it is difficult to show a direct comparison on one sheet without re drafting the original baseline.

Do not try to put the logic back into your As Built programme - it will always be challenged.

As I said before with collapsed As Built - just don’t go there.

Best regards

Mike Testro.

Hi Peter

The most important factors to take into account when deciding on a delay analysis are:

1. Is the work in progress? Then the only suitable method is an Impacted as Planned.

2. Is the work complete? Then everything depends on how good your As Built Records are.

3. If you are a sub-contractor sandwiched between other trades then an As Built v As Planeed works well for the other trades if combined with a Time Impact Analysis for your own work.

4. An Impacted as Planned in a forensic scenario will be criticised for being theoretical and unreallistsic and should be avoided.

5. A time Impact Analysis works well if your records are up to it. If not you are exposed by a contesting approach using better or different records.

6. Don’t bother with an As Built But For at all.

Best regards

Mike T.

ROGER,

What’s that all about???

’as planned impacted’ retrospective analysis using the ’windows’ methodology"

Please share with us your process, methodology, difinitions??

Have you written a book about this?? Can we buy in amazon?

Or if not, you have some referrals, reference??

Would agree with Mike on that.

As built but for programmes require the analyst to put in / take out links that are "in his or her opinion" the correct thing to do.

One of the easiest forms of programmes to attack and find errors in or possible different interpretations - as Mike pointed out, resulting in the analysis being thrown out.

Mike was rather charitable in his remarks, from memory there was alot of wrong links in the analysis in the City Inn case.