IMPACTED AS PLANNED Vs AS BUILT

Rami,



I think you have summed it up nicely.

Thank you Mike, Andrew and Pute,



obviously it is a debatable issue! from my modest experience i would agree with Andrew! especially when it comes to time constraints to prepare the schedule! but then again! i agree with Mike since most of the times preparing the schedule with lots’ off SS and FF renders the updates useless and inefficient in showing a remaining works sequence!



I guess a proper way to handle this thing is just to keep them SS and FF to a minimum! just in the same way you cannot really avoind using long activity durations especially when dealing with procurement or when you try to avoid lags.



thank you all again!

Mike,



"a situation where one activity cannot finish until a preceding activity has also finished" - isn’t that a FF relationship? Can not 100% complete plastering walls until the blockwork is 100% complete for example.



The SS lag type link that springs to mind is for concrete curing rather than a separate activity for curing.



eg SS(16) to represent the follow on activity cannot commence until the concrete has cured for 14 days and 2 days to get the first pour ready. Say a single activity that represents a slab construction with ten pours in it. The steel column erection can start 16 days after the first concrete pour is complete on the first poured section.



If more global activities are used, (although not the best way of doing it by far), then SS(?) and FF(?) will have a valid use.



But yes I totally agree, it’s preferable that the activities are broken down to a level of detail so that FS links can be properly used - but sometimes the constraints on producing the programme mean that level of detail can not be achieved, at least initially, (as the time period in which to issue the programme is often the constraint which means proper detail can not be put into the programme. The 1$Billion project and 14 days to submit a programme type scenario, lawyers not planners put that clause in the contract!!!!!).

Hi Andrew



In a normal construction sequence I really cannot think of a situation where one activity cannot finish until a preceding activity has also finished.



As for SS links this is usually a result of sloppy planning where 1 activity has a number of FS predecessors and the planner puts in 1 FS link and then a series of SS links to the others.



As for lead lags they work to distort the critical path.



The situation you describe where there is endless float happens when a FS link is missing - there has to be at least 1 outgoing FS link from every activity even if it is to Project Completion.



I have to adjust evry contractors programme before starting on a delay analysis.



Best regards



Mike Testro

Although I agree with the sentiment that FS links are to be used where ever possible SS & FF links do have thier use.



It’s just reality, usually due to lack of time, that global activities are used and have to be linked in using SS & FF links rather than the ideal detail being produced allowing only FS links to be used.



Probably FF links are of more use than SS.



Every activity has two relationships:



1. It can / can not start until .....

2. Unless the activity is finished some other activity can / can not start/finish - unless it is truely the last activity in the sequence of events.



Most programmes identify and model the first relationship but often never consider the second one unless it is a FS relationship, which is not always the case.



How many programmes have you seen where float on an activity, (or more usually huge numbers of activities), runs from the end of the activity to the completion date and is many months long??? Totally meaningless.



Absolutely NIL chance of the activity or chain of activities becoming critical if delayed as there is no link to subsequent activities which would also be delayed by the knock on effect.



There is a previous thread on here about using -(ve) lag - I’m still of the opinion that people who do this should be shot!!!!!!!

Hi,



Lot of SS or FF relationship does not means that programme is claim oriented.One of the reason could be resource constraint for the contractor.He could have planned to mobilize his resources to other activities.



I assume you are analysing a 14.1 Programme if that is the case ask your contractor to provide you the schedule documentation showing each and every reason for the relationships, assumed productivity & also any contingency if there (to avoid confusion on free float at later stage).



Cheers!

Hi Rani



I have not yet to find any reason why a SS or FF link should be used in a construction programme.



We had a big discussion on this topic in PP recently and the end result was that neither could anyone else.



These links are used because the software allows the facility but they should be banned.



You will not get a true critical path when SS and / or FF links are used.



I suspect that there are also + or - lead lags on the links and that the bars contain either multiple tasks or multiple locations or maybe both.



For istance - M&E 1st fix all floors - 15 weeks.



If this is the case a proper and accurate delay analysis impossible.



In presenting such a programme the Contractor may have thought he was being clever but the most likely answer is that the planner was just lazy.



If he does present a claim you will have no difficulty in rejecting it on the valid grounds that:



1. There is no distinct critical path

2. There is insufficient detail to establish the purpose of the lead / lag SS FF links.

3. The global activities do not allow accurate allocation of impacted events.



If the contractor then tries to resubmit his programme for a new attempt then he will be accused of rigging it to support his claim.



The professional approach is to request that a fully detailed bottom up programme be submitted for approval now - before any claims start to come in.



Best regards



Mike Testro

Hello Mike,



I’m very much interested in what you have presented here! i have recently become more involved into claims/claims analysis and i’m still just picking up on the subject! the discussion here was enlightening and enriching!



I have a question though! when a schedule has a lot a of SS and FF relationships! is that a sign of bad intentions! I’m reviewing a schedule where the contractor deliberately doubled lnked the activities such that one activity is linked with FS and FF relationship at the same time! i still can’t figure out if it’s claim oriented!!!



can you help!



thank you!

Hi Puneet



That is why IAP analysis is discredited for forensic delay analysis.



But it is the only method to be used during construction.



The better the baseline the less weird the results.



Best regards



Mike Testro

Mike,



I completely agree with you.



As I said earlier we get weird results in IAP due to theoretical nature of the projected delay that are determined based on the contract programme.



Even if Baseline programme is set up for delay analysis with a clear critical path , IAP gives only the theoretical results and hence sometimes the outcome of IAP is weird.

Hi Puneet



When I do a Time Impact Analysis the Contract Programme overlays the As Built programme.



When events are impacted on the Contract Programme - one by one - there are three possible results.



1. The Impacted activity is still short of the As Built - in which case something else caused the delay

2. The imapcted activity falls within the As Built Envelope - in which case cause and effect is reasonably established.

3. The Impacted activity shoots past the As Built Envelope in which case the Contractor must have done somthing different to what was planned. If you know what was done differently then re-create that in the logic. If you don’t know then you have to imagine what could have reasonably been done to bring it back to the As Built.



You will get weird results if the Baseline programme is not set up for delay analysis.



If you have not got a responsive baseline with a clear critical pth formed on Bottom Up principles then it is a waste of time to do any form of delay analysis.



Best regards



Mike Testro

Hi Mike,



I am not mixing TIA with IAP. TIA and IAP are completely different approach as you also said.



I am trying to say that most of the times IAP gives strange results and then the contractor / engineer put the as-built line on the IAP to make it realistic. Now this step is common to TIA where you first Impact the programme and then put the as-built status on it.



Use of IAP depends on the contract, if both the parties agreed to use IAP even if As-Built records are available, I don’t see any harm in use of IAP in this case.

Hi Puneet



You seem to be mixing up Time Impact Analysis with Impacted as Planned.



When using a Time Ipmact analysis it is essential to try to demonstrate how and why the planned sequence of work changed to what actually happened.



Therefore the As Built programme has to be demonstrated before the analysis starts.



Part of the analysis may well prove acceleration and/or mitigation.



With an Imapcted As Planned analysis you do not show the As Built programme because the system only works with Work in Progress where no As Built data exists.



Best regards



Mike Testro

Khawaja,



I don’t think its a good approach to put as-built line on your IAP Schedule. as IAP gives you the entitlement and no the time required to complete the project. after putting the as-built line you are showing the realistic completion date but not the entitlement. I will say this is your accelerated completion date (as you must have taken some mitigation or accelerated steps)



Also this approach is not recognized in delay analysis.



This approach looks like TIA but should not be mixed up with TIA.



Rememeber :" IAP shows your Entitlement"

Hi Khawaja



You are thinking of embarking on a Time Impact Analysis which s the most complex and the most reliable form of analysis.



To embark on a Time Impact analysis you need three sets of data.



1. A fully responsive Baseline Programme that is based on sound Bottom Up principles.



it must not have any:



1.1 Start or End Constraints

1.2 Lead lag links

1.3 SS or FF lainks - only FS links.

1.4 No activity more than 10 days duration.



It Must have



1.5 A clear critical path from start to finish

1.6 Every activity to have at leat one downstreamm FS link to another activity - even if it is Project Completion.



If you do not have a baseline that fits these criteria then your analysis will not work.



2. A detailed events schedule that sets out:

2.1 The impact date of the event which includes all lead times - this represents the latest date that the impacted activity can start - or finish.

2.2 A reference to the activity - or activities that is imapcted.



3. A detailed As Built Programme that shows - at least - the earliest start date and the latest finish date for each activity. This is called the As Built Envelope.



Now you are ready to embark on a Time Impact analysis.



You will have to enter the events onto the baseline progemme one at a time starting from the earliest impact date and link it to the imapcted activity - watch for:



1. Does the critical path move?

1.1 If NO then go to the next event and repeat.

1.2 If YES then look to see how the event has moved to the AS Built programme - there will be three possibilities:



1.2.1 The Activity has not reached the As Buit Envelope - in which case something else has caused the delay - more research is necessary becaus ethe implication is that the Contractor has caused the delay.



1.2.2 The Activity fits within the As Built Envelope in whic case reasonable cause and effect has been established.



1.2.3 The activity shoots beyaond the As Built Envelope in which case the the Contractor has done something to mitigate the delay. If you do not know what has been done then you must re-create what a reasonable contractor would have done in the cirumstance - change logic - increase resource or gang sizes etc.



Now repeat the excercise for every event on your schedule taking a note of every cause and effect as you go.



When finished you can start to write up your delay narrative.



Best regards



Mike Testro

Daer khawaja,



If you have an approved program of works, and you have the actual date of execution agreed by both parties, and your software allows you to input the actual dates, then you have yourself "As Built" Program of works. You can base you EOT on it.



If on the other hand, you do not have actual completion dates for all activities, but you have and approved schedule of works, then you can perform the "Impacted As Planned" method.



Best Regards,



Samer