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Modern Delay Analysis Techniques

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1 Modern Delay Analysis Techniques
Scott Adams BEng LLB PgD LLM CEng MICE FCIArb MAPM MAE Scott Adams Consultants Ltd. 505 Winfield Commercial Bldg. 6-8 Prat Avenue, TST, HK Tel: , Fax: Web:

2 Modern Delay Analysis Techniques
‘Static’ methods Only one network used: Delays added into it, or subtracted from it – progress not accounted for ‘Dynamic’ methods Several networks used, ‘updated’ either in real time or retrospectively – progress accounted for [AACE International Recommended Practice No.29R-03 “Forensic Schedule Analysis”: 5-level taxonomy, giving 8 broad methodologies described over 105 closely-typed pages]

3 Contents The Mirant case Windows analysis – an example
Other RDA techniques Advantages and disadvantages The City Inn Case Problems of programming

4 Mirant v Ove Arup [2007] Summary observations of HHJ Toulmin at 564: “Windows analysis, reviewing the course of a Project month by month, provides an excellent form of analysis to inform those controlling the Project what action they need to take to prevent delay to the Project.” “Without such analysis those controlling the Project may think they know what activities are on the critical path but it may well appear after a critical path analysis that they were mistaken.”

5 Windows Analysis “The expert must not only be familiar with the chronology, he must tell the story in his report. … Some would say that the software exercise counts for nothing unless backed up by the narrative.” John Marrin QC: Expert Evidence on Delay and Disruption – The Tribunal’s Perspective

6 Windows Analysis Example project: Civil Engineering Works
But - exactly the same programming principles apply in building works projects

7 Windows Analysis Example project: Bridge and Approach Road;
Start date 01-Jan-07; Date for Completion 30-Jun-07; (6 month project) Main Contractor a bridge specialist; but not a road-works specialist – so this will be sub-contracted out

8 Bridge forms critical path (6 months to construct)
Approach Road has 66d of “float” 66d THE INITIAL PROGRAMME (Carefully planned and resourced)

9 Events in First “Window” (Jan/Feb)
Day 1: Excavation starts; S/C bids compiled; Day 10: VO1 issued, increasing the depth of abutment foundations – 20d extra excavation required; Day 25: Road Subcontract awarded (NB. 5d late); Day 58 (End of window): (i) Abutments excavation almost completed; (ii) Road paving cannot be sourced (materials shortage)

10 1st window VO1 Increased depth: 20d additional excavation Subcontract award after 25d (5d late) Paving not commenced due to material shortage 20d delay due to VO1 SITUATION AS AT END OF FEB 07 (Close of First ‘Window’)

11 Events in 2nd “Window” (Mar/Apr)
Day 60: Excavation of abutments completed; Day 75: Pavement laying commenced Day 90: Concreting of abutments completes slowly, taking 30d in total (so a 14d delay); Day 100: VO2 – major instruction for a further ½km of road, in difficult ground (on piles) – planned at 21d to source piling s/c, 30d to drive 30 piles, 20d to test, 30d to construct new road & drains, and 15d for street furniture Day 120 (End of window): No further delays, but due to massive VO2, the approach roads are now on the critical path

12 Slow Concreting of Abutments (14d delay)
2nd window Slow Concreting of Abutments (14d delay) 21d VO2 New 0.5km of road; in poor ground (on piles) 48d delay; (20d VO1, 14d slow abutments; 14d VO2) SITUATION AS AT END OF APR 07 (Close of Second ‘Window’)

13 Events in 3rd “Window” (May/Jun)
Day 121: Falsework erectors go on strike for the whole month of May Day 135: Contractor says that he will mitigate the delay by doubling up resources on the commissioning stage; Day 160: VO3 – 10 more piles instructed in the new piled approach section, these will take an extra 10 days to complete Day 181 (End of window): No further delays, but due to the month-long strike, the bridge has become once again more critical than the approach road

14 One month lost due to falsework s/c strike
3rd window One month lost due to falsework s/c strike Mitigation: commissioning now only 8d 21d VO3: Additional piles instructed at new road VO3 66d delay; (20d VO1, 14d slow abutments; 14d VO2; 25d strike; -7d mitigation) SITUATION AS AT END OF JUN 07 (Close of Third ‘Window’)

15 Events in 4th “Window” (Jul/Aug)
Day Day 243: Further problems with Falsework erectors – not all were pleased with strike settlement terms, and productivity suffers. Day 243 (End of window): No further delays; approach road completed bar for commissioning; but the elevated bridge concrete deck only managed completion at the very end of this period. The bridge thus remained more critical than the approach road throughout.

16 SITUATION AS AT END OF AUG 07 (Close of Fourth ‘Window’)
More than one further month lost due to poor falsework s/c productivity 21d 98d delay; (20d VO1, 14d slow abutments; 14d VO2; 25d strike; -7d mitigation; 32d poor falsework productivity) SITUATION AS AT END OF AUG 07 (Close of Fourth ‘Window’)

17 Events in 5th “Window” (Sep/Oct)
Day 270: VO4, some new road markings and revised drainage causes an extra 10d of work. Day 289 (End of project): The project completes on 16 October 2007, some 108 days late. Critical VOs:- VO1=20d, VO2=14d; VO4=10d: Total = 44d

18 New Road marking scheme
5th window 21d VO4 New Road marking scheme 108d -108 SITUATION AS AT END OF OCT 07 (Close of Fifth ‘Window’)

19 20d 14d 10d

20 As-Built Subtracted Analysis
Take the as-built programme, and subtract the delays which the contractor has suffered (which are not to his own default). This gives rise to a theoretical date, the date on which the contractor would have finished but for the delays The difference between the ABBF date, and the actual completion date represents the potential entitlement to EOT



23 As-Built Subtracted Analysis
The “longest path” is favoured Only the VOs on the longest path feature in the subtraction, irrespective of the contemporary criticality of other VOs Thus, VO1 (20d) and VO4 (10d) are those which, when subtracted, cause the ABBF date to be collapsed back in time. Thus the potential EOT entitlement here is 30d (cf. 44d in the windows analysis)

24 As-Planned Impacted Analysis
The initial programme (warts and all) is taken, and into it are impacted all of the delays which the contractor has suffered The impacts are ‘added’ into the initial network; sometimes this is done in ‘real time’, but this causes problems if the delays are caused late due to the contractor’s own problems (e.g. a VO instructed at a late stage merely because of earlier contractor’s delays);

25 THE INITIAL PROGRAMME (Carefully planned and resourced)


27 As-Planned Impacted Analysis
The impacts take no account of progress, or of any of the contractor’s own defaults. The resultant date is again a theoretical date, perhaps best described as the date for which the contractor would have programmed if it had know about all of the additionally instructed work at the outset; If the VOs are impacted in chronological order, then they all figure in this example: VO1=20d; VO2=28d*; VO3=10d; VO4=10d: Total = 68d (cf. 30d ABBF, 44d windows analysis) * Net delay given initial float and the prior occurrence of VO1

28 Advantages & Disadvantages
The ‘static’ analyses (APIP, ABBF) are simple, requiring only two sheets of paper for a ‘before and after’ effect; But their results are theoretical, there is no account of progress made, no account of changes to the plan, no account of mitigation The ‘windows’ analysis does take account of such factors, which may account for the warm reception in the Mirant case; but this does come at a cost of complexity, and the programmes must be reliable … also:

29 Advantages & Disadvantages
“Although the status at the start and end of the window will allow any delay to be quantified it will not in itself demonstrate the cause or causes of delay. Analysis of these [intra-window] delaying events can be carried out by using any method which is applicable, dependant upon the activities and the events in question. It may be appropriate to use a ‘collapsed as-built’ or an ‘as-planned impacted’ methodology …” Lowsley, Linnett “About Time”, p.90

30 HK Standard Form (Private Form)
Upon it becoming reasonably apparent that the progress of the works is delayed, the MC shall forthwith give written notice … and if in the opinion of the Architect the completion of the works is likely to be or has been delayed beyond the DfC by … [the various reasons] …then he shall as soon as he is able to estimate the length of the delay … make a fair and reasonable extension of time for the completion of the Works …”

31 City Inn v Shepherd Construction [2007]
Scottish Decision (only of persuasive value in HK) JCT-style contract (‘actual’ and ‘likely’ delay can give rise to EOT) Pursuer’s expert used some form of CPM; Defender’s expert used an “as-planned vs as-built” chart (not a CPM analysis and seemingly not capable of discerning likely delay)

32 City Inn v Shepherd Construction [2007]
“ Consequently I think it necessary to revert to the methods that were in use before computer software came to be used extensively in the programming of complex construction” “The older methods are still plainly valid, and if computer-based techniques cannot be used accurately there is no alternative to using older non-computer-based techniques.”

33 City Inn v Shepherd Construction [2007]
“ … in the type of programme used to carry out CPM analysis any significant error in the information fed into the programme can invalidate the whole analysis … it is easy to make such errors” “That seems to me to invalidate the use of an as-built CPM analysis to discover after the event where the critical path lay, at least … where full electronic records are not available from the Contractor.”

34 City Inn v Shepherd Construction [Appeal: 2010]
CONCURRENT DELAY (Lord Carloway) The initial exercise to be carried out by the architect occurs upon the application of the contractor, who will have requested an extension of time by intimating, under clause 25.2, that the progress of the Works "is being or is likely to be delayed". He will claim that a Relevant Event has been the, or at least a, cause of the delay. The architect then has to decide whether he considers that the completion of the Works is likely to be delayed by a Relevant Event beyond the Completion Date (clauses and 2).

35 City Inn v Shepherd Construction [Appeal: 2010]
CONCURRENT DELAY (Lord Carloway) This provision is designed to allow the contractor sufficient time to complete the Works, having regard to matters which are not his fault (i.e. Relevant Events). This does not, at least strictly, involve any analysis of competing causes of delay or an assessment of how far other events have, or might have, caused delay beyond the Completion Date. It proceeds, to a large extent, upon a hypothetical assumption that the contract has proceeded, and will proceed, without contractor default. It involves an assessment, on that assumption, of the delay which would have been caused to the Completion Date purely as a result of the Relevant Event.

36 City Inn v Shepherd Construction [Appeal: 2010]
CONCURRENT DELAY (Lord Carloway) But the exercise remains one of looking at the Relevant Event and the effect it would have had on the original (or already altered) Completion Date. If a Relevant Event occurs (no matter when), the fact that the Works would have been delayed, in any event, because of a contractor default remains irrelevant. In that respect, the view of HHJ Seymour QC in Royal Brompton Hospital NHS Trust v Hammond & Others (No 7) [2001] 76 Con LR 148 (at para 31), that a Relevant Event falls to be disregarded if a pre-existing contractor default would nonetheless have caused the delay, appears to be in error.

37 10d 10d 28d 20d

38 City Inn v Shepherd Construction [Appeal: 2010]
CONCURRENT DELAY (Lord Carloway) VO1 = 20 days; VO2 = 28 days; VO3 = 10 days; VO4 = 10 days (So the “Lord Carloway approach” might give a 68 day entitlement – the same as the as-planned-impacted in this example).

39 Common Programming and Planning Problems
Planner often a junior/inexperienced staff member; No resources are considered in programmes; Programmes are bar-charts, with no logic; The ‘concertina’ effect – programme depicts completion on time, even after several delays have occurred; “OP = PC”; PC certified for commercial (secret) reasons; The programme becomes a commercial or political document, not a project management tool

40 The “Magic Circle”

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