BF202 BUILDING CONSTRUCTION & TECHNOLOGY 2

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BF202 Building Construction & Technology 2

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School of the Environment



Semester 2

Examinations 2006
-
2007





BF
202


BUILDING CONSTRUCTION

& TECHNOLOGY 2




Instructions to Candidates


Time allowed:
THREE
hours


Candidates are to attempt
Section A

which is compulsory, and worth 25% of the total
marks;
plus

THREE

other questions, worth 25% each.


Section A is a multiple choice question which should be answered by providing crosses
within the template provided.



ONE

question only should be attempted from the following sections

Section B

Demolition

and substructure

Section C

Superstructure and enclosure

Section D

Finishes and post contract structural alterations


The examination questions are based upon pre
-
issued information comprising:
-



Preamble and outline information.



Soil report



Drawings 009.1;

009.2; and 009.3.












Tuesday 29 May 2007, 9:00
-
11:00hours

BF202 Building Construction & Technology 2

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Section A


Candidates are to attempt all questions

within this section by placing a cross

in the
template on your desk and

selecting the most appropriate answer to the following
questions.



ONE MARK PER QUESTION


Soils and foundations
.


1.

Cohesive soils:
-

(a)

should be allowed to dry to provide a stronger shear strength.

(b)

should be tamped to compress the soil and so provide a stronger bearing
capacity.

(c)

should be made smooth, with e
xcavator teeth marks removed.

(d)

s
hould be covered with concrete as soon as possible after the formation level
has been established.


2.

Pad foundations of a framed building will:
-

(a)

always be at the same formation level.

(b)

always be the same size.

(c)

v
ary in level and size.

(d)

always be constructed of reinforced concrete.


3.

In
-
situ

bored piles formed principally through a cohesive soil but founding

on a non
-
cohesive soil will:
-


(a)

be lined through their entire length.

(b)

be lined only through the non
-
cohesive strata.

(c)

not require any lining at all.

(d)

not be used.


4
.

‘Backstop water
-
bar’ is used in basement construction because:
-

(a)

it keeps ground water and
water
vapour from entering the building.

(b)

it protects reinforcement embedded in the concrete a
s well as keeping water
from entering the basement at construction joints.

(c)

it
can be simply adhered to the structure after concreting.

(d)

it can be hidden by internal finishes.


5
.

The D/B factor is a multiplication factor which:
-

(a)

allows for the
soil’
s
resistance embraced by the bulb of pressure emanation
below a structure founded within a cohesive soil.

(b)

allows for the
soil’s
resistance embraced b
y the bulb of pressure emanating

below a structure founded within a non
-
cohesive soil.

(c)

converts the

shear strength of a non
-
cohesive soil into the Ultimate Bearing

Capacity of the soil.



(d)

r
educes the U.B C by a factor of 3.


6
.

Continuous Flight Auger piles are not used:
-

(a)

because of possible vibration damage to adjacent buildings during their
formation
in the ground.

(b)

to construct contiguous piled walls.

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(c)

b
ecause of the need for lining of the piles prior to the pouring of concrete.

(d)

in areas where limited headroom exists.

7.

‘Top Up and Bottom Down Construction’ allows:
-

(a)

a roof slab of a building to be constru
cted at ground level.

(b)

the above
-
ground structure to be finished before work below ground has
been completed.

(c)

for extra storeys to be added to a structure at a later date.

(d)

for foundation design to be a non critical activity.




8.

A reinforced concrete basemen
t raft is constructed with
a series of
down
-
stand
beams in

order to:
-

(a)

allow a plastic soil to be contained below the raft.

(b)

make the overall raft structure lighter.

(c)

protect the soil below the edges of the raft from freezing.

(d)

allow a heavy cl
adding system to load the perimeter of the building.


Structure


9
.

Steel framed structures have advantages ove
r in
-
situ concrete reinforced
structures
because:
-

(a)

off
-
site fabrication allows for a safer system of working on site when erecting

the fame
.

(b)

lead
-
in times are less than that for in
-
situ concrete framed buildings.

(c)

fire proofing of the structure is no more complicated than that for reinforced
concrete structures.

(d)

such buildings have less dead weight than reinforced concrete buildings.


10
.

High rise structures obtain their rigidity by:
-

(a)

diaphragm floors being incorporated into the structure.

(b)

strategically placed shear walls constructed on alternate floors.

(c)

continuously rising shear walls forming core(s) which provide load tra
nsfer.

(d)

continuously rising shear walls
forming cores
connected to diaphragm floors.


11
.

Shear studs are used to:
-

(a)

prevent shear failure in
concrete
floors.

(b)

p
rovide structural continuity between steel beams and
concrete
floors.

(c)

allow for th
e fixing of profile metal decking.

(d)

allow the use of pre
-
cast concrete floor slabs to be used without the need for

‘stitching’ reinforcement across the floor beams.


12
.


Table
-
form


formwork systems allow:
-

(a)

formwork to be struck
quickly, typically,

one day after concrete decks have
been poured.

(b)

beams to be shuttered between adjacent table
-
forms.

(c)

plate floors to be quickly constructed and struck so improving floor cycle

times.

(d)

unlimited reuse of the sheathing plywood in contact with the c
oncrete.


13
.

Wind acting on the gable ends
of a
Portal Frame is resisted

by:
-

(a)


building its short side into the prevailing wind.

(b)


using universal beam sections for

stanchions attached to fixed
-
bases.

(c)


using universal beam sections for stanchio
ns attached to pinned
-

bases.


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(d)

using rigid joints between roof a
nd

column members with horizontal

bracing
in the

end bays of the roof structure

together with vertical

bracing to transfer

loads into the

ground


Enclosure



14
.

Rainscreen cladding provi
des protection by:
-

(a)

preventing wind and rain penetrating the cladding system.

(b)

absorbi
ng k
inetic energy so allowing no

wind driven rain to impinge upon the
structure.

(c)

allowing a reduced quantity of rain to collect behind the rain
-
screen
in front of
an airti
ght barrier and to drain away.

(d)

soaking up water and dispensing of it during dry windy conditions.


15
.

Dense

bricks used
as the external skin of a masonry
cladding system for high

rise
const
ruction
:
-

(a)

prevents frost damage to the cladding during below f
reezing temperatures.

(b)

provides an impervious surface through which wind driven rain cannot pass.

(c)

provides additional structural stability to the frame to which it is attached.

(d)

allows rainwater to cascade down the face of the building which at t
ime
s

of
high wind speeds is likely to enter the cavity.


16.

The width of mastic joints between pre
-
cast concrete panels attached to an in
-
situ
concrete frame should be:
-

(a)

as small as possible.

(b)

wide enough to allow for the drying and movement of the concrete fr
ame.

(c)

v
ar
ied in width to match the dimensional accuracy of the

concret
e

frame
.

(d)

wide enough to allow the mastic to be trowelled in.


17

L
oad
-

bearing pre
-
cast concrete cladding is often employed to:
-

(a)

dispense with edge protection during the construction of
the structure.

(b)

allow the structure to proceed without the reliance on the continued supply of
the pre
-
cast panels.

(c)

reduce the number of columns poured and so reduce the cranage time for
each floor cycle.

(d)

allow intricate facings

or tooling

to be

applied to a quality produce
manufactured in factory conditions.


18
.

E.P.D.M. is used:
-

(
a)

to form a DPM to the internal face of basement walls.

(b)

as a single skin roofing membrane.

(c)

as a sarking felt below roof tiling in an unventilated roof syste
m.

(d)

as a flashing on the abutment between brickwork and roof tiling.


19
.

Wind
-
posts are incorporated into an enclosing masonry walling system to :
-

(a)

d
ecrease the effective length of a wall between supports.

(
b)

reduce the need for vertical expansion

joints.

(
c)

provide head restraint to the masonry wall by fixing the top of the post to the

concrete
soffit

above.

(d)

provide resistance to the masonry system as well as adding extra propping

to

the

perimeter of the structure.


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20
.

Drying vents are i
nstalled above concrete decks:
-

(a)

to prevent condensation forming on the soffit of the concrete deck.

(b)

to release entrapped moisture from beneath the roof covering.

(c)

to allow the release of moisture vapour

from a wet screed and the concrete

deck.

(
d)

to prevent condensation forming beneath the roof covering.



Finishes


21
.


Intumescent mastic is:
-

(a)

a carbon based product used to reduce the passage of sound through
service

holes

within ceiling voids.

(b)

used to maintain fire integrity by filling

small voids within fire compartment

walls

and floors.

(c)

used as a baffle to reduce the passage of impact sound between metal
ducting and the structural frame of a building.

(d)

a thixotropic material

which cures with the presence of moisture.


22
.


An
un
-
bonded sand/cement screed laid upon a dense concrete substrate must:
-

(
a)

be laid with a minimum thickness of 65mm in bay sizes not greater than
15m
2
.

(b)

be laid with a minimum thickness of 40mm in bay sizes not greater than
12m
2.

(c)

be laid with a mi
nimum thickness of 40mm in bay sizes not greater than
12m
2

(d)

not be laid over a heated floor.


23
.


The general rule for the component parts of a three

coat sand/cement render mix

is
to:
-

(a)

e
nsure that the cement content is the same for all three coats

wit
h its overall
hardness being greater than the substrate,

(b)

ensure that each successive coat contains extra cement such that each coat
becomes harder, the final coat matching the strength of the substrate.

(c)

ensure that the first coat is less hard than the subs
trate and each successive
coat is less hard than the previous coat.

(d)

ensure that each coat is applied and finished with a steel trowel.


24
.

The fixings for a 12.5mm plasterboard ceiling applied to 50mm wide timber joists

at
600mm centres should be:
-

(a)

galvan
ised nails, 38mm long at 150mm centre
s generally but at 10
0mm at




perimeter edges.

(b)

sheradised screws, 32mm long at 150mm centres generally but at 100mm at

perimeter edges.

(c)

sheradised screws, 32mm long at 200mm centres generally but at 150mm at

perimeter
edges

(d)

plasterboard screws 38 mm long fixed at no greater than 150mm centres.


25
.

Which of the following is not an on
-
site admixture to gypsum cement?

(a)

Sand to BS 1198 and 1199 (Building Sand From Natural Sources.)

(b)

Vermiculite

(c)

O.P.C.

(d)

Barytes.

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Please ensur
e that

you
have
filled in the
multiple choice template together with your
candidate number
.



Section B

You are to attempt one question from this section


Demolition and
Substructure



Question 26


(a)

Explain the manner and purpose of undertaking risk assess
ment prior to or during
the drafting of a method statement for the safe and effective demolition of the three
storey brick Edwardian warehouse presently occupying part of the development site


(10 marks)


(b)

The demolition contractor has proposed to hand
-
demolish the warehouse, with
mechanical loading of the debris.

Discuss the main features of hand demolition and critically appraise the decision to
hand demolish the warehouse.

(15

marks)



Question 2
7


(a)

It is proposed to provide earthwork support to th
e basement by means of sheet
piling.


Describe the manner by which the piling would be pitched and propose two
methods by which restraint can be provided to the piles prior to bulk excavation.














(15

marks)













(b)

Detail by means of

annotated sections two different means of providing a watertight
construction joint between the slab and the external walls of the basement


(10 marks)


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Section C

You are to attempt

one question from this section


Superstructure

and enclosure


Question
28


(a)

Describe how the use of pr
e
-
cast reinforced concrete components

can improve
the
floor

cycle time of a structure with in
-
situ cast reinforced concrete floors.

(10 marks)


(b)

A r
ecent BRE survey showed that sof
fit levels on in
-
situ concrete frames v
ary
between


19 mm to + 16 mm from their true datum level and columns can vary by
+/
-

25 mm in position.


Explain and offer solutions as to how this can lead to problems of fit in the incorporation of
spandrel, non
-
structural, pre
-
cast concrete cladding p
anels to the office block.

(15 marks)



Question 29


It has been suggested that the flank ends to the office block structure could be replaced by
full height, structural reinforced concrete cladding panels.


(a)

Discuss
both
advantages

and disadvantages

for th
e above proposal.

(5

marks)


(b)

Detail the manner of attachment of the panels to the in
-
situ concrete floors.


(10 marks)



(c)

Detail a drained joint detail between two structural pre
-
cast concrete storey
-
height
cladding panels.












(10

marks)


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Section D

You are to attempt at least one question from this section


Finishes and Post Contract Alteration works


Question 30


(a)

(i)

By annotated sketches, discuss the features of a suspended ceiling system
that

would allow uninterrupted access into
the ceiling void of the office block.


(15

marks)


(ii)

Detail the junction between a quarry tile floor and wall tiling in a toilet area.


(10 marks)


OR

(b)

(i)

Detail the fixing of marble floor and wall cladding to the entrance hallway of
the office bloc
k.








(15 marks)


(ii)

By annotated sketches describe the manner of forming a deep platformed
access floor for the provision of services above the concrete plate floors.


(10 marks)


Question 31


Some time after completion of the property, subsequent t
o the end of the defects liability
period, the developer has been able to let the top two floors.


As part of the fit
-
out the tenant requires an additional lift between the said two floors. An
additional
hydraulic 6

person lift is proposed to be sited with
in the vicinity of grid lines 4 to
8.


(a)

Based upon structural considerations d
iscuss and propose an ideal location for the
position of the lift.

(10 marks)


(b)

Considering the remainder of the building will stay occupied during the upgrading
works,

pro
pose and fully describe a
method for the concrete "cutting" ope
ration
including:
-




Preliminary requirements



Protection



Means of disposal of debris.

(15

marks)