1. Network planning Learning objectives After these lectures you should be able to: - Produce and analyse activities networks - Calculate earliest and latest start and finishing times for activities - Calculate activity floats and determine the critical path(s) through a network - Update networks as new information becomes available

2. PDM Footings/1 wk Brickwork/3 wks Roof/ 2 wks Landscape/1 wk Fence/1 wk

3. A ES EF t LS LF TF FF A = Activity description, i.e. ‘Brickwork’ t = Duration (usually in work days) ES = Earliest Start EF = Earliest Finish LS = Latest Start LF = Latest Finish TF = Total Float FF = Free Float

4. Network analysis Forward pass 0 1 1 4 4 6 6 8 A/1 B/3 D/2 F/2 1 1.5 1.5 2 C/0.5 D/0.5 ES EF NOTE: ES for the first activity is ‘0’, not ‘1’! Name/Duration

5. Network analysis Backward pass 0 1 1 4 4 6 6 8 A/1 B/3 D/2 F/2 0 1 1 4 4 6 6 8 1 1.5 1.5 2 C/0.5 D/0.5 5 5.5 5.5 6 ES EF NOTE: The backward pass starts with the same Name/Duration LF value as the last EF for the final activity LS LF

6. Activity Draw an PDM network for this project. Then do a forward and backward pass. Activity Duration Depends on A 5 None B 5 A C 12 A D 3 C E 6 B and 2/3 of C F 8 B and 2/3 of C G 14 A H 5 D, E, F and G

7. Solution 13 21 F/8 13 21 0 5 5 10 13 19 A/5 B/5 E/6 0 5 8 13 15 21 5 13 13 17 17 20 21 26 C1/8 C2/4 D/3 H/5 5 13 14 18 18 21 21 26 5 19 G/14 7 21

8. Development of a network Level 1 Level 2 Level 3 Final

9. Activity Float Critical activities: Have no float and are therefore fixed in time. ES = LS and EF = LF Total Float (TF): The amount of time that an activity can be delayed, without that affecting the project completion time. TF = LF – EF = LS – ES Free Float (FF): The amount of time an activity can be delayed, without that affecting the start of any following activity. FF = ES( any following activity ) – EF

10. 13 21 F/8 13 21 0 5 5 10 13 19 A/5 B/5 E/6 0 5 8 13 15 21 5 13 13 17 17 20 21 26 C1/8 C2/4 D/3 H/5 5 13 14 18 18 21 21 26 5 19 G/14 7 21 Determine the Critical Paths(s) and all activity floats!

11. Activity TF FF Critical? A 0 0 Yes B 3 3 C1 0 0 Yes C2 1 0 D 1 1 E 2 2 F 0 0 Yes G 2 2 H 0 0 Yes Critical Path = A - C1 - F - H

12. 13 21 F/8 13 21 0 5 5 10 13 19 A/5 B/5 E/6 0 5 8 13 15 21 5 13 13 17 17 20 21 26 C1/8 C2/4 D/3 H/5 5 13 14 18 18 21 21 26 5 19 G/14 7 21 Critical Path (A – C1 – F – H) highlighted in network

13. Tutorial: Critical Path Method (CPM) Carry out a critical path analysis for the following project in order to determine the total completion time for the project and the critical activities. Illustrate the critical path(s) in the CPM network. Calculate and list the Total and Free floats for all activities. Activity Duration Depends on activity A 3 weeks - B 2 - C 5 A D 6 A and B E 4 Half of D F 4 C G 5 D H 8 C and E I 9 D J 6 I and H K 18 B L 4 K