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# MRE5003 Industrial Techniques In Maintenance Management Assignment 3

Assignment 3, 2019: Networks, scheduling and analysis

 What is required? Worked solutions for all activities, with graphical charts as appropriate, submitted by email. What is it worth? 20% of total marks for the unit

Activity 3A

Shutdowns in major asset intensive organisation are planned in line with Project

Management techniques. The activities required for a small maintenance project are given in the table, based on maintenance delivery plan.

Constraints are:

• No more than a total of 5 people are available.
• All the people are multi-skilled and inter-changeable
• Once one work is started, it needs to be finished the available people before they move to the next job
• If a job requires 3 people for 2 days then it needs three people and cannot be done with 2 people for 3 days.
• Overtime working is not allowed.

3A.1 Complete the table and draw a network for the job. Show the critical path and its length.

3A.2 Show with a bar chart how you would allocate the labour to jobs.

3A.3 The project proceeds well, BUT at the start of Day 6, one worker calls by phone with a medical certificate for 3 days off (i.e. Day 6 and Day 7). Refine the schedule to show how this affects the project duration. (Note: you cannot go back in time! Reconfigure the plan from Day 6 onwards).

 Activity People required at the same time Duration (days) EFT LFT Float 1-2 3 3 1-3 2 4 2-4 4 3 2-5 5 3 3-4 3 4 4-5 2 4

Activity 3B

A plant improvement project in your workplace consists of 10 activities, and is to be done by contractor. Your estimates of the durations (in weeks) for each of the activities are shown in the table.

 Activity No Optimistic time Most likely time Pessimistic time 1-2 4 10 16 1-3 6 6 6 1-4 3 5 9 2-6 3 7 11 3-5 2 2 2 3-6 6 4 10 3-7 4 7 10 4-5 5 5 5 5-7 4 8 10 6-7 2 4 6

3B.1 Calculate the estimated time and the standard deviation on that estimate for each activity.

3B.2 Establish the critical path and semi critical path for the project, the estimated project completion time and standard deviations.

3B.3 What is the probability of the project taking more than 23 weeks?

3B.4 If the job can be done in 18 weeks, will result in a bonus of \$100 000. What is the likelihood of this happening?

3B.5 What completion time should be specified in the contract if you want to be 97% certain that it will be done in that time?

3B.6 Draw the network for this project in a time-scaled Activity-on Arrow format.

Activity 3C

You are planning for an essential plant safety upgrade project using your own people. In your planning, based on your experience, you have assembled the data in the table below:

The only way that the outage can be shortened is by using additional resources from contractors and crashing any or all activities where that is possible, but it can be possible at the extra cost as shown in the table below.

 Activity Normal Crashed Te days \$ cost Tc days \$ cost \$ rate/day 1-2 6 12000 3 18000 1-3 4 4000 3 8000 2-4 3 3000 3 n/a 2-5 2 8000 2 n/a 3-4 7 2000 4 5000 4-7 3 3000 1 4500 4-8 5 6000 4 11000 5-6 6 8000 3 14000 6-9 5 4000 2 9000 7-9 7 2000 5 4000 8-9 4 2000 3 4000

3C.1 Draw the network for this job.

3C.2 Mark clearly the critical path. Find the total cost of both methods of completing the work.

3C.3 What is the optimum duration of the outage at minimum total cost when overheads and other indirect costs of \$3000 per day are included? Set out your calculations using the table layout below, and show your results with an optimisation chart from a spreadsheet.

 Project duration Obtained by reducing: Additional direct cost Progressive total direct cost \$ Progressive Total cost \$ Notes