Scheduling Resource Planning CTC415 Schedule Compression Used to

Scheduling & Resource Planning CTC-415

Schedule Compression • Used to decrease schedule time – At what price? • Does cost of compression outweigh liquidated damages or possible profit from next job started early – What are costs? – extra crew, equipment – Benefits – less equipment time on job – How do you reduce time? • Increase daily output on activity – Increases costs – Labor & Equipment

How to Compress a Schedule • Look at critical path and determine activities which cost the least per day • Look for logic revisions which could shorten schedule – Make sure that revisions don’t cause increased costs • Painting and flooring can be done concurrently but at a loss of productivity – Keep activity relationships in mind

How to Compress a Schedule • Activity Duration Reduction – Activities have a minimum duration • IF 2 painters can paint a room in 2 days – how long does it take 4 painters? , 8 painters, 16 painters • Setup times and cleanup times are always present – Results in increased costs – Must watch CP to make sure it does not shift

Cost vs duration Linear relation – only true to a point Step function shows equip needs Linear with break points Parabolic costs increase as duration decreases

• Indirect costs change with project length – Shortened project reduces indirect costs – Lengthening projects increase in direct costs

• How to compress schedule – 1. Determine CP – 2. Look for cheapest activity on CP and reduce 1 day – check CP (any movement) – 3. Go to 2 – 4. If multiple CP then must cut activities on all CPs – 5. Total cost and days reduced

Example cut 6 days Activity A B C Days 2 1 1 Cost/day $1200 $600 $800 Activity H I J Days 3 3 4 Cost/day $800 $2000 $1500 D E F G 3 1 4 2 $1000 $900 $500 $700 K L M N 1 2 1 1 $1000 $900 $700 $600

Scheduling Decompression • May be able to increase duration of activity and decrease cost – Why? • Keep crew busy • ahead of schedule and payment • slow down to keep handle on $ – How? • Look at increasing duration by reducing crew