Delay Analysis

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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: 2312 1708, Fax: 2723 1738

Web: www.scadacon.com.hk

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Modern Delay Analysis

Techniques 1.‘Static’ methods

• Only one network used: Delays added into it, or

subtracted from it – progress not accounted for

2. ‘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]

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Contents

• The Mirant case

• Windows analysis – an example

• Other RDA techniques

• Advantages and disadvantages

• The City Inn Case

• Problems of programming

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Mirant v Ove Arup [2007]

• “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.”

Summary observations of HHJ Toulmin at 564:

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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

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Windows Analysis

• Example project: Civil Engineering Works

• But - exactly the same programming

principles apply in building works projects

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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

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Bridge forms critical

path (6 months to

construct)

THE INITIAL PROGRAMME (Carefully planned and resourced)

Approach Road has

66d of “float”

66d

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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)

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VO1

Increased depth: 20d

additional excavation

Subcontract award

after 25d (5d late)

Paving not commenced

due to material shortage

SITUATION AS AT END OF FEB 07 (Close of First „Window‟)

1st window

20d delay

due to VO1

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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

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2nd window

SITUATION AS AT END OF APR 07 (Close of Second „Window‟)

Slow Concreting of

Abutments (14d delay)

VO2

New 0.5km of road; in

poor ground (on piles)

48d delay; (20d VO1, 14d

slow abutments; 14d VO2)

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21d

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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

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3rd window

One month lost due to

falsework s/c strike

VO3: Additional piles

instructed at new road

VO3

SITUATION AS AT END OF JUN 07 (Close of Third „Window‟)

66d delay; (20d VO1, 14d slow abutments;

14d VO2; 25d strike; -7d mitigation)

Mitigation:

commissioning

now only 8d 21d

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Events in 4th “Window” (Jul/Aug)

• Day 182 - 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.

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SITUATION AS AT END OF AUG 07 (Close of Fourth „Window‟)

4th

window

More than one further

month lost due to poor

falsework s/c

productivity

98d delay; (20d VO1, 14d slow abutments;

14d VO2; 25d strike; -7d mitigation; 32d

poor falsework productivity)

21d

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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

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-108

5th

window

SITUATION AS AT END OF OCT 07 (Close of Fifth „Window‟) 108d

VO4 New Road marking

scheme

21d

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Jan Feb Mar Apr May Jun Jul Aug Sep Oct

Jan Feb Mar Apr May Jun Jul Aug Sep Oct

-70 -70

2007

Time v Delay Chart

-50 -50

-60 -60

-30 -30

-40 -40

-10 -10

-20 -20

10 10

0 0

30 30

20 20

50 50

40 40

70 70

60 60

90 90

80 80

2007

110 110

100 100

1st window [20d

delay]

2nd window

[48d delay]

3rd window

[66d delay]

4th window [98d

delay]

KEY:

BRIDGE

APPROACH ROAD

VO1VO2

VO3

VO4

S/C issued

late

Lack of paving

materials

Approach Road

construction

completed

Slow abutments

progress

Falseworker

Strike action

Mitigation by

increasing

commissioning

teams

Poor falsework

productivity

Bridge complete

108d late

20d

14d

10d

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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

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AS-BUILT BUT-FOR / AS-BUILT SUBTRACTED ANALYSIS

VO2

VO3

VO1

VO4 -108

21d

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AS-BUILT BUT-FOR / AS-BUILT SUBTRACTED ANALYSIS

-78

30d

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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)

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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);

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THE INITIAL PROGRAMME (Carefully planned and resourced)

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VO1

VO2,

VO3 VO4

-68d

THE INITIAL PROGRAMME IMPACTED WITH VO1-VO4

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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

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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:

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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

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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 …”

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• 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)

City Inn v Shepherd

Construction [2007]

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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.”

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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.”

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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 25.3.1.1 and 2).

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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.

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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.

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Jan Feb Mar Apr May Jun Jul Aug Sep Oct

Jan Feb Mar Apr May Jun Jul Aug Sep Oct

-70 -70

2007

Time v Delay Chart

-50 -50

-60 -60

-30 -30

-40 -40

-10 -10

-20 -20

10 10

0 0

30 30

20 20

50 50

40 40

70 70

60 60

90 90

80 80

2007

110 110

100 100

1st window [20d

delay]

2nd window

[48d delay]

3rd window

[66d delay]

4th window [98d

delay]

KEY:

BRIDGE

APPROACH ROAD

VO1VO2

VO3

VO4

S/C issued

late

Lack of paving

materials

Approach Road

construction

completed

Slow abutments

progress

Falseworker

Strike action

Mitigation by

increasing

commissioning

teams

Poor falsework

productivity

Bridge complete

108d late

20d

28d

10d

10d

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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).

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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

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The “Magic Circle”

Work to that

programme until

something occurs

which makes it

impossible

Examine and quantify

the effects on

the programme

Produce a viable,

working programme

with full reasons

for all revision(s)