Construction & Project Management Questions 2022

Construction & Project Management
Q1)
Q2)
i) Critical path: activities with zero slack of head event and zero slack for tail event
A => C => E => G
ii) Completion time = 2 + 2 + 4 + 5 = 13
iii) Variance = σ 2p = ( 2
6 )
2
+ ( 2
6 )
2
+( 4
6 )
2
+ ( 5
6 )
2
=1.3611
Q3a)
Activity Activity time ES EF LS LF LS-ES
A 6 0 6 4 10 4
s 1,8
3,16
2,12
7,12
12,12
16,9
15,4
F
4,9 5,4
9,9 10,4

B 8 15 23 15 23 0
C 3 23 26 23 26 0
D 6 26 32 26 32 0
E 6 6 13 10 16 3
F 7 13 20 16 23 3
G 5 0 5 10 15 10
H 8 5 15 15 23 10
I 2 13 15 18 10 3
Completion time = 32 weeks
Total cost = £198,000
Cost on CP = £180,000
Number of critical path = 1
Critical path = B => C => D
3b) Crash
Activity Activity time ES EF LS LF LS-ES
A 4 0 4 3 7 3
B 4 4 8 4 8 0
C 2 17 19 17 19 0
D 4 19 23 19 23 0
E 4 7 11 9 13 2
F 6 11 17 13 19 7
G 3 4 7 10 13 6
H 6 7 13 13 19 6
I 2 11 13 7 9 4
Completion time = 23 weeks
Total cost = £316,000
Cost on CP = £296,000
Number of critical path = 1
Critical path = C => D
The project would take between 32 and 23 weeks depending on the activity
completion time that vary between the normal time and the crash time.

 Crashing activity B by a week an additional cost of 6,000 would be incurred
 Crashing activity C by a week an additional cost of 2,000 would be incurred
 Crashing activity D by a week an additional cost of 3,000 would be incurred
The best choice would be to crash an activity having the lowest incremental
(additional) cost – therefore, in this case we would choose to crash activity C by one
week at an additional cost of 2,000