Task:
The table below lists the activities for a construction project together with their respective durations and resource allocation. The construction dependencies are also provided.
(a)Construct the network diagram for the project in the format of activity on the node (or Precedence Diagram). Undertake a numerical assessment of the network (EST, LST, EFT, LFT, TF, FF, TTA), identify the critical path and state the overall duration of the project.
|
Activity |
Duration (weeks) |
No. of Resource (per week) |
Construction Dependencies |
|
A |
3 |
3 |
A commences immediately. |
|
B |
6 |
4 |
B succeeds A and precedes E. |
|
C |
5 |
6 |
C follows A, but must complete prior to the start of H and F. |
|
D |
7 |
9 |
D begins when A has ended, and it must complete before K & G commence. |
|
E |
4 |
5 |
– |
|
F |
5 |
5 |
F precedes J & K, both of which must finish prior to L starting. |
|
G |
6 |
7 |
G will also have completed before L begins. |
|
H |
8 |
8 |
H also follows B and precedes J. |
|
J |
3 |
2 |
– |
|
K |
3 |
2 |
– |
|
L |
7 |
8 |
L is the final activity which commences upon completion of activity E. |
(b)Prepare a fully annotated bar chart and its corresponding resource histogram resulting from consideration of earliest start (EST) and latest finished (LFT) time (2 sets of bar chart and histogram).
[Note – the histograms to be plotted manually on the supplied grid paper]
(20%)
(c)Examine the two resource histograms produced in (b) then carry out a resource smoothing exercise for the project (illustrating an optimum gradual increase in resource at commencement of the contract, followed by a similar reduction towards completion). The tabulated resource element above represents the number of operatives required per week for the completion of each activity in the duration shown. Assume resources are unlimited. State the maximum number of resources needed (1 set of bar chart and histogram).
(d)Provide your optimum resource levelled histogram and contract Gantt chart to illustrate the effect of a maximum number of 20 labourer resources available, whilst maintaining the project deadline.
Assume that activities may be interrupted (as long as they finish within their total time available). Any troughs in the final levelled histogram must be avoided. The logic presented in the precedence diagram must also be maintained (1 set of bar chart and histogram).
What delay would be incurred (if any), if the project deadline was no longer critical?
(e)For the final contract programme (Gantt chart) for the constrained levelled resources obtained produced in (d), if each activity in the project now requires the use of a crane, for its full duration, on top of its labour. The contractor owns two suitable cranes and intends to utilise them on the project at a cost of £1685/week each. Additional cranes may be hired in when required at a cost of £2215/week each. With the aid of the Gantt chart (produced in d), determine the minimum cost of craneage for the project work. You must demonstrate continuous usage for all cranes and therefore may utilise some or all of the available activity float (Bar chart showing crane usage).
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