Laddering

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Laddering
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Pipe Laying Project Example

• Pipe Laying Project Tasks (WBS)
• Dig a trench
• Lay the pipe
• Test?
• Refill the trench
• Assume the times required to trench, lay the
  pipe, and refill the trench are equal

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Pipe Laying Project Schedule (1)

Trench
Lay pipe
Refill
3 time units

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Pipe Laying Project Schedule (2)
1 time unit
2/3 time unit
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Pipe Laying Project Schedule (comparison)
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Pipe Laying Project Scheduling

• The assumption that all immediate preceding
  activities must be 100 complete is too
  restrictive for some applications
• Where appropriate, break activities into segments
  and use laddering so the following activities can
  begin sooner and not delay the work

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End