Question

Pennywise Construction has just made the winning bid of $4.9 million to construct a new facility for a major corporation. The corporation needs the facility to be available within a year. Therefore, the contract includes the following provisions: • A penalty of $200,000 if Pennywise has not completed construction by the deadline 48 weeks from now. • To provide additional incentive for speedy construction, a bonus of $125,000 to be paid to Pennywise if the facility is completed within 40 weeks. Pennywise is assigning its best construction manager, Andrew Hawthorne, to this project to help ensure that it stays on schedule. Mr. Hawthorne is very pleased to receive this latest assignment as the project manager for such an important project. He looks forward to the challenge of bringing the project in on schedule, and perhaps earning a promotion in the process. However, since he is doubtful that it will be feasible to finish within 40 weeks without incurring excessive costs, he has decided to focus his initial planning on meeting the deadline of 48 weeks. He will need to arrange for a number of crews to perform the various construction activities at different times. The table below shows a list of the various activities, their immediate predecessors, and three estimates reflecting the time required to complete each activity. Activity List for the Pennywise Construction Co. Project Activity Activity Description Immediate Predecessors Most likely duration (in weeks) | Optimistic duration (in weeks) Pessimistic Duration (in weeks) 3.5 2 6 18 A B C D E F 5.5 C 4.5 1 E 6.5 Excavate Lay the foundation Put up the rough wall Put up the roof Install the exterior plumbing Install interior plumbing Put up the exterior siding Do the exterior painting Do the electrical work Put up the wallboard Install the flooring Do the interior painting Install the exterior fixtures Install the interior fixtures E, G C F, I H I J K L M 4 5.5 Η N KL 5.5 Given all the information in the table, use PERT/CPM to help Mr. Hawthorne address to the following questions. Note: If you use Excel to solve any part of this problem, be sure to upload a copy of your Excel file along with your test file but be sure to clearly and explicitly state your answer to the question within the test document (in other words, don't expect the instructor to assume the answer based on your Excel file). In addition, explicitly state in the test document when there are calculations associated with an answer contained in the Excel file. A. Create the network diagram representing the problem. B. What is the total time expected to be required to complete the project if no delays occur? C. What are the earliest and latest start and finish times for the individual activities required to meet the expected project completion time provided in question B (show your method for

Given all the information in the table, use PERT/CPM to help Mr. Hawthorne address to the following questions.

A. Create the network diagram representing the problem.

B. What is the total time expected to be required to complete the project if no delays occur?

C. What are the earliest and latest start and finish times for the individual activities required to meet the expected project completion time provided in question B (show your method for determining this)?

D. Which are the critical bottleneck activities where any delays must be avoided to prevent delaying project completion?

Answer 1

Based on the given table, we find the expected duration of each activity as shown below:

The expected duration for each activity is found out using formula shown in the duration column. The above table in form of formulas is shown below for better understanding and reference:

A. Based on the duration of each activity, we prepare the project network diagram as shown below:

The above network diagram in form of formulas is shown below for reference and better understanding:

The above project diagram is prepared as per legend shown in top-left corner.

EST = Early start time

LST = Late start time

EFT = Early finish time

LFT = Late finish time

SLK = Slack = LST - EST or Slack = LFT - EFT

The EST of an activity = EFT of previous activity

EFT of an activity = EST + Duration - 1

Similarly LFT & LST are calculated during backward pass. The activity END is added to facilitate backward pass calculations and is only a dummy activity.

There are multiple paths in the diagram:

1. A-B-C-D-G-H-M

2. A-B-C-E-H-M

3. A-B-C-E-F-J-K-N

4. A-B-C-E-F-J-L-N

5. A-B-C-I-J-K-N

6. A-B-C-I-J-L-N

Out of above paths, path A-B-C-E-F-J-L-N is the longest path and has 0 slack. Hence, this is the critical path.

B. As seen from above, the total time expected to be required to complete the project if no delay occur = 44 weeks

C. The earliest start, latest start, earliest finish, latest finish times are shown in the project network diagram. The start and finish dates are shown in the box for each activity as per legend in top left corner of the network diagram.

D. The activities on critical path are bottleneck activities i.e. A,B,C,E,F,J,L,N