answer the survey Quations .short 3 answers

Project Management (Example Problem)

1. The Selby Builders, Inc. will construct a new and unique office building for a Glassboro based CPA firm. The project will involve several activities; some can be done concurrently and others must be done in sequence. Based on previous knowledge and experience, Selby’s management has identified the activities and the order in which they must be completed. Though the new office building will be unique, Selby’s construction manager has made a best guess of the completion time for each activity. (I) The CPA firm wants to know how long would it take to construct the building. (II) Selby’s subcontractors must know when to schedule each activity. (III) In addition, Selby would like to know how long each activity can be put off without delaying the entire project.

ACTIVITY DESCRIPTION IMMED. PRED. TIME ESTIMATES (Days)

A Order Structural Materials ------- 2

B Obtain Structural Workers ------ 4.5

C Excavate ------ 5

D Pour foundation C 6.5

E Receive Structural Materials A 4

F Frame Structure B, D, E 30

G Install Plumbing F 20

H Install Electricals F 10

I Finish Interior G, H 15

J Finish Exterior G 14.5

K Clean-up I, J 5

2. Further to the above precedence relationship data, it has been determined that Selby’s construction activities will be impacted by weather variation in the region. The decision makers of Selby have determined that the following pessimistic time, deterministic time, and most likely time will be appropriate to the situation.

ACTIVITY IMMED. PRED. TIME ESTIMATES EXPECTED TIME VARIANCE

a m b

A ------- 1 2 9 3 1.78

B ------- 2.5 4.5 9.5 5 1.36

C ------- 2 5 14 6 4

D C 4 6.5 18 8 5.44

E A 2 4 18 6 7.11

F B, D, E 22 30 50 32 21.78

G F 15 20 37 22 13.44

H F 4.5 10 21.5 11 8.03

I G, H 12 15 24 16 4

J G 14 14.5 48 20 32.11

K I, J 5 5 5 5 0

(I) Find the project duration, critical path, and the schedule for each activity. (II) What is the probability that the project will be completed in 100 days? (III) What is the probability of

completing the project in 84 days?

(3) Let us suppose the management of the above construction company would like to crash the activities based upon the data provided in problem #1 and the table below. Formulate the problem as a Linear Programming Problem and find the optimal cost to crash the project network.

ACTIVITY NORMAL TIME UNDER NORMAL CRASH MAX CRASH TIME MAX. CRASH COST COST CRASH COST/ DAY

(N j ) (N

j

/ ) (C

j ) (C

j

/ ) DAY (M

j ) (K

j )

A 2 1 500 1200 1 700

B 4.5 2.5 1200 2300 2 550

C 5 4 1500 2000 1 500

D 6.5 5 1500 3000 1.5 1000

E 4 2 1100 2900 2 900

F 30 20 15000 22000 10 700

G 20 17 12000 15000 3 1000

H 10 7 8000 9800 3 600

I 15 8 9000 13900 7 700

J 14.5 12 10000 12000 2.5 800

K 5 4 6000 6650 1 650