Question

You have prepared the following schedule for a project in which the key resource is a backhoe. This schedule is contingent on having 3 backhoes. You receive a call from your partner, Brooker, who desperately needs 1 of your backhoes. You tell Brooker you would be willing to let him have the backhoe If you are still able to complete your project in 11 months. Develop a resource schedule in the loading chart that follows to see if it is possible to complete the project in 11 months wit only 2 backhoes. Be sure to record the order in which you schedule the activities using scheduling heuristics. Activities 5 and 6 require 2 backhoes, while activities 1. 2. 3.and 4require 1 backhoe. No splitting of activities is possible. Can you say yes to Brooker's request? 4 15 3 1 3 0 2 2 Legend ESİ ID IEF SL LS 7 29 SL 0 3 3 Resource Schedule the resource load chart with ES and Slack updates ID RES DUR ES LF SLO 1 2 3 4 5 6 7 8 9 10 11 12 13 3 1 3 03 0 4 12 2 73 5 2 4 3 70 6 2 2 7 9 0 Resources scheduled Resources available2 22 22 22 22 22 22

Answer 1

Note the following rules to find Early Start (ES), Early Finish (EF), Late Start (LS), and Late Finish (LF).

ES of the starting activities = 0ES of all other activities = Max. (EF of their immediate predecessors)EF of an activity = Its ES + Its durationLF of ending activities = Their EFLF of all other activities = Min. (LS of their immediate successors)LS of an activity = Its LF Its duration

Note that in this problem, the time constrained schedule is given with the following values of ES, EF, LS, LF, and Slack.

Note the resource loading based of Early Start schedule (without considering any resource constraint).

Note that for the 1^st and 4^th month, the resource requirement becomes more than two while the available resources per month are 2 only. So, resource leveling is necessary to find a feasible schedule.

Month 0 to 1

Eligible activities are 1, 2, and 3. Minimum slack is for activity 3. So, load activity 3 first. Next, load activity 2. Now, loading activity 1 is not possible because the resource limit is reached.

Month 1 to 2

The eligible activity is 1. But loading 1 will violate the resource constraint.

Month 2 to 3

The eligible activity is 1 only. So, load 1.

Month 3 to 4

Eligible activities are 4 and 5. Based on minimum slack, load 5 first4. Now it is not possible to load activity 4 due to resource constraint.

Month 4 to 5: Although activity 4 is eligible, it cannot be loaded due to resource constraints.

Month 5 to 6: Although activity 4 is eligible, it cannot be loaded due to resource constraints.

Month 6 to 7: Although activity 4 is eligible, it cannot be loaded due to resource constraints.

Month 7 to 8: The only eligible activity is 4. So load 4.

Day 8 to 9: No activity can be loaded.

Day 9 to 10: The only eligible activity is 6. So load 6.

The resource constraint-based scheduling shows that even with 2 backhoes, it is possible to complete the project by 11 months. So, it is possible to consider the mentioned request of lending one backhoes.