As bulit but for

Hi Tim

As Built but for and Collapsed as Built are synonimous.

The system is applied if there is not a viable responsive baseline - you only need a start and finish date.

The method assumes that all the periods of delay are within the As Built programme so if the delay periods are removed the As Built will collapse to where is should have been but for the delay.

The method is easily challenged because the analyst has to put a critical path into the as built data and one guess is a good as. another. This also assumes that the As Built records are good enough to start with.

I avoid the method entirely.

Best regards

Mike T.

Hi Tim

I did not understand your distinction between Tort and Contract - particularly in respect of UK construction law.

Best regards

Mike Testro

Hi Tim

The choice of methods to be used on a delay analysis is the chief skill of a delay analyst.

Send me a private message with your email and I will send you a decision tree to assist in the selection.

Best regards

Mike Testro

Dear Mike,

What would be your prefered method if good as-built information is available?

Regards,

Gustav

Hi Gustav

Most times Good is not good enough.

Ideally the records should state Who did What Where and When at weekly intervalls and linked to the task UTID.

This rarely happens - at best you can ascertain when a task starts and finishes.

In a forensic situation this is usually good enough for a Time Impact Analysis.

Best regards

Mike Testro

"As-built but for" and "as-built collapsed" (ABC) mean the same thing. They refer to a method whereby delay is calculated by measuring the change in project duration after subtracting representations of delay events on the backward pass.

"As-planned impacted" (API) is the equivalent method whereby delay is calculated by measuring the change in project duration after adding representations of delay events on the forward pass.

ABC ignores the original as-planned schedule. API, equivalently, ignores the as-built schedule.

In a tort case, where there is no planned schedule, and the relevant comparison is actual (if tort did not occur) versus actual (given tort did occur) ABC is more likely to be appropriate.

Hi Anders

Providede always that you can establish a verifiable critical path on the As Built programme - see Sheperd v City Inns and Great Eastern Hotel v Laing

Best regards

Mike Testro

Mike,

The critical path is more than you need on an As-Built Collapsed. The critical path is determined by a forward pass and then a backward pass. With the ABC, however, you only need to calculate the longest path length on the backward pass. You do not need a forward pass at all. Similarly with the API and the time impact analysis, you only need to know the longest path length on the forward pass; you don't need to perform a backward pass at all.

Strictly speaking, the ABC, the API and the TIA are not true critical path-based methods, as they only deploy one of the two passes!!

(...That's in the absence of resource levelling, btw. If you have resource levelling, you may still make use of float calculations to determine the levelling priority, which requires both passes...).

Hi Anders

You still have to put logic into the As Built programme and that is where the method fails.

Best regards

Mike Testro

Yes, Mike, that's very true.

I believe the ABC method was originally conceived for hand-drawn ADM (Arrow Diagramming Method), AOA (activity-on-arrow) or AON (activity-on-node) networks. A claimant or architect/engineer would just write the numbers for a revised backward pass in a red pen over the as-built data, and then two sets of numbers could be compared. (The various editions of the textbook by Antill & Woodhead - which I think is probably still one of the best textbooks on construction scheduling even though its first edition was in 1970 - are very good on this).

Conventional modern software like Primavera, Microsoft Project etc., however, does not lend itself readily to this method because the as-built data left of the data date is "dead" and so it has to be reconstructed into a "live" logically linked network - an extra step that is often more trouble than it's worth.

This is not true for every software product, however - PMA's Netpoint, for instance, keeps the network logic live left of the data date!

Hi Anders

In Asta PowerProject each data date is stored in the software and can be swithced on or off as required.

Best regards

Mike Testro