BE221 Construction Methods
s
School of the Environment
Semester 2 Examinations 2005-2006
BE221
CONSTRUCTION METHODS
Instructions to Candidates
Time allowed: TWO hours
Attempt Question ONE and TWO (Both Compulsory)
and any other TWO questions
Each questions carry equal marks
Friday 2 June 2006, 16:00 – 18:00 hours
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BE221 Construction Methods
Question 1 (compulsory)
A contractor is using a tracked mounted excavator/loader machine for excavation
work on site. The plant has a peak output of 200 cubic metres bulked material per
hour. The excavation is a basement 140m by 45m by 6m deep in clayey soil
overlaid by a 1.0m fill material;
(a)
Using justifiable estimates and bulk factors of 1.3 and 1.15 for the clay and fill
material respectively, calculate:
(i)
Bulk volume of excavated material;
(ii)
Normal output of the excavator (show all calculations and assumptions;
(iii)
The overall operational efficiency factor of the excavator;
(iv)
Actual output of the excavator (show all calculations and assumptions.
(10 marks)
(b)
If the tipping ground is 40 km away from site, and the average speed for
haulage trucks is 30 km/h, determine how many suitably sized trucks would be
required for the excavator to work non stop (allow 10 minutes for dumping,
turning and accelerating from the tip).
(5 marks)
(c)
Plot a Haulage Diagram to depict your results in (b).
(d)
If the contractor owns the excavator but has to hire the haulage trucks, how
many trucks would he require to achieve optimum hire cost?
(5 marks)
(5 marks)
Question 2 (compulsory)
A construction manager has asked you to produce a method statement for the
construction of a deep basement for the new tower block at the University of
Brighton, Watts carpark area (Appendix 1.0). The site set up has been completed,
you are to focus on providing the detail to enable the substructure works to
commence.
(a)
Produce descriptive and design method statements to carry out the substructure works and identify the constraints that may affect the construction
process.
(15 marks)
(b)
Using your descriptive and design method statements produce a table that lists
all the construction activities in order of sequence. Your table should also
identify the corresponding resources required for each activity.
(10 marks)
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BE221 Construction Methods
Question 3
The promotion of Health & Safety may be in direct conflict with demands for
increased productivity on site. As a construction manager, discuss how you would
ensure that this conflict does not arise or is minimised.
(25 Marks)
Question 4
A construction manager has to make key decisions and evaluate project conditions
in order to choose the most appropriate construction methods for a building project.
(a)
Briefly list and describe the ten factors that govern the selection of
foundations.
(15 marks)
(b)
Discuss (with the aid of sketches) the factors affecting the structural grid and
what understanding is required in order to develop appropriate construction
methods.
(10 marks)
Question 5
(a) Briefly list and describe the main factors that govern the selection of
construction plant.
(10 marks)
(b)
Using the values below as constants, determine a realistic range of unit cost in
relation to the plant output (best value for money range) beyond which any
attempt to increase or decrease the output would result in a dramatic increase
in costs.
An excavation plant have a weekly running costs
A total fixed charges
It is required to excavate
(Rc) = £8,000
(Fc) = £18,000;
(Tp) = 120,000 cu.m.
The maximum plant output possible (i.e. beyond which the plant is overworked) is 30,000 cu.m per week.
(15 marks)
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BE221 Construction Methods
Question 6
A contractor for a project in a confined city centre site is proposing to use either
secant piling or diaphragm walling to retain the sides of a 140m by 45m by 6m deep
excavation.
(a)
Discuss the suitability of each of the above support systems for such sites
and select with reasons the optimum system for the project.
(15 marks)
(b) Produce detailed method statements for the installation of your chosen system.
(10 marks)
Question 7
The main issues of concern when selecting Slipform systems are:
i)
The basic methods of slipforming chosen;
ii) Advantages and disadvantages for using slipforming;
iii) The planning factors.
Project management consultants for a high rise project have decided to use Slipform
construction as their strategy for the construction of the concrete core that houses
the staircase and lift shafts.
(a)
Discuss (with the aid of sketches) how the above issues would be addressed to
achieve an effective and efficient delivery of the project.
(15 marks )
(b)
Discuss the advantages and disadvantages of replacing the concrete core with
a steel-framed core system.
(10 marks)
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BE221 Construction Methods
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