The Challenges of Programming Construction Projects and Delay Analysis By Keith Kirkwood BSc FRICS, FCIArb, FCInstCES Chief Executive Bennington Green Ltd

Topics Covered 1.A history of Time in Construction Projects 2.How Construction Projects Programmed 3.Understanding links in Construction Programmes 4.Cause and Effect 5.Choice of Delay Method

Project Management

Great Pyramid of Giza

Taj Mahal - India

Joseph Priestly & William Playfair 1786 William Playfair ‘Commercial and Political Atlas’ 1765 Joseph Priestley’s ‘Chart of Biography’ plotted some 2000 famous lifetimes on a time scaled chart

Karol Adamiecki & Henry Gantt

The early basic Gantt chart was a simple "fill in the bar" method to show how much of the project was complete Basic Gantt Chart

As the use of Gantt grew in the early 1900’s the double bar Gantt Chart grew in popularity. Basic Gantt Chart Double Bar

The basic Milestone chart shows only important project events or milestones Milestone Chart

Hoover Dam - USA

PERT chart for a project 5 milestones (10 through 50) 6 activities (A through F). The project has two critical paths: activities B and C, or A, D, and F – giving a minimum project time of 7 months with fast tracking. Activity E is sub-critical, and has a float of 1 month. PERT Diagram

Trident Missile Project - USA

Excavate 2 days Concrete 2 days Brickwork 6 days Coping 2 days Design 5 days Order Concrete 4 days Order Bricks 10 days Activity on Line / PERT Diagram Event No Float Start Finish

Simple four activities all Critical Excavate Concrete Brickwork Coping Activity Description ES LS Dur Float EF LF Activity Link Activity on Node Diagram

Excavate Concrete Brickwork Coping Design Order Concrete Order Bricks Activity on Node Diagram Critical Path shown in Red

Primavera Chart

Hong Kong Airport

London Olympics

Employer Defines scope / Set contractual Terms Contractor analyses risk and use CPM programme then looks at: 1.Pruning critical path activities 2.“Fast tracking" (performing more activities in parallel) 3.“Crashing the critical path" (shortening the durations of critical path activities by adding resources) 4.Re-programming non critical activities to save cost 5.Resource balancing Only then should they price the project. Produce contract programme after award. How Construction Projects Are Programmed

The normal sequential relationship of one activity following another. Activity B cannot start until activity A has finished. Activity A Activity B Links in construction Projects Finish - to - Start

‘d’ implies a normal lag relationship between activities A and B; that is, B cannot start until ‘d’ days have elapsed after activity A has finished. Activity A Activity B d Links in construction Projects Lagged Finish-to-Start

Activity B cannot start until activity A has started or perhaps, more accurately, activity B can start at the same time as activity A but not before it. Activity A Activity B Links in construction Projects Start-to-Start

‘ d’ indicates a start-to- start relationship with the delay imposed showing that activity B cannot start until the period ‘d’ has elapsed after activity A has started. Activity A Activity B d Links in construction Projects Lagged Start-to-Start

A finish-to-finish relationship, activity B cannot finish until activity A has finished. It implies that B can finish at the same time as A, but not before it. Activity A Activity B Links in construction Projects Finish-to-Finish

A finish-to-finish relationship but with a delay, ie activity B cannot finish until ‘d’ days have elapsed after activity A has finished. Activity A Activity B d Links in construction Projects Lagged Finish-to-Finish

There may be occasions where a lag is required both on the start and finish of related activities. Activity B cannot start until ‘d’ days after activity A has started and activity B cannot finish until ‘t’ days after activity A has finished. Activity A Activity B t d Links in construction Projects Lagged Start and Finish

The arrangement in which the successor activity is allowed to start chronologically before the predecessor activity has been completed. Activity B cannot start until 4 days before activity A is planned to finish. Activity A Activity B -4 Links in construction Projects Negative lag

Most project management software allows the planner to specify that an activity must start or must finish on a specific date. Using the software in this way restricts the ability of the programme to react dynamically to change on the project. Effectively setting milestones. Such programme settings are referred to as constraints Links in construction Projects Must Start / Must Finish

1.Errors in original programme 2.Contractor proposed programme changes 3.Changed Conditions 4.Employer Changes 5.Contractor Changes 6.Design Errors or required design changes 7.Circumstances not envisaged at time of tender How Delay Arises

1.What has caused the delay? 2.What is the extent of the delay caused? 3.What programme items were effected? 4.What are the effects of the delay on the programmed items? 5.Who is responsible for the delay under the Contract? 6.Employer Delay Event or Contractor Delay Event Cause and Effect

1.The relevant conditions of contract 2.The objective of reaching a fair and reasonable conclusion economically and proportionately 3.The nature and timing of the causative events 4.The value of the dispute 5.The time available 6.The records available 7.The programme information available 8.He programmers skill level and familiarity with the project 9.The timing of the analysis in relation to the completion of the works Choice of Delay Analysis Method

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