CN106 Engineering Surveying

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Nov 15, 2013 (3 years and 10 months ago)

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CN106 Engineering Surveying





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s


School of the Environment



Semester 2 Examinations 2006
-
2007



CN106


ENGINEERING SURVEYING






Instructions
:


Time allowed:

THREE

hours


Answer:

Answer

ALL

questions


Items supplied:

Math
ematical Formulae


All working must be shown














Wedne
sday 6 June

200
7
, 09:00


12:00 ho
urs


CN106 Engineering Surveying





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Question 1


(a
)

On a construction site, a rectangular building ABCD is to be set out
from two control points

S1 and S2 using a total station.


The coordinates of the building co
rners and control points

are

_______
__
__________________________

Point or



Coordinates


building corner


mE



mN

___________________________________

A


150.000

150.000

B


169.445

130.555

C


180.052

141.162

D


160.607

160.607


S1


155.089

174.253

S2


182.954

179.657

_______
__________
__________________


Calculate


(i)

the data required to set out the building from
control point
S1


(ii)

the data required to check the building sides and diagonals











(10

marks)



(b
)

On site, engineers may have to work with a
survey grid
, a
site grid

and a

structural grid
.


Describe,
with the aid of diagrams
, each of these grids and
how they
are

used for setting out.


What precautions must be taken when dealing with coordinates
specified on these different grids?










(10

marks)



CN106 Engineering Surveying





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Question 2


(a)

A des
ign point P is to be set out from a control point C using a steel
tape. The coordinates of P are 241.010mE, 174.050mN and those of C
are 201.684mE, 165.368mN.


The 50 m tape to be used to set out P has been standardised on a
baseline of length 48.345 m as
follows:


Temperature 4

C

Tension applied

to tape 100 N

Length recorded on tape = 48.331 m


At the time P is to be set out, the temperature is 12

C and 50 N tension
is to be applied to the tape. The height of C is 32.210 m and the height
of P is 31.524 m.
The tape has a cross
-
sectional area of 2 mm
2
.


Calculate the reading that is to be used on the tape to set out point P.
Assume that the 1
.000

m point is to be held at C and that the tape is to
be laid on the ground.


Note: Physical constants for steel are
given on the formula sheet for
the exam.










(14

marks)



(b)

A two
-
peg test is carried out on an optical level with the following
results


First set of readings

Level set up midway between two pegs A and B 60 m apart.

Reading on the staff at A = 1.60
8

Reading on the staff at B = 1.484


Second set of readings

Level set up on the line AB extended 6 m from B

Reading on the staff at A = 1.455

Reading on the staff at B = 1.371


Calculate


(i)

The collimation error in the level per 60 m of sight.


(ii)

The re
adings that should have been obtained at A and B in the
second set of readings if the level did not have a collimation
error.











(6

marks)


CN106 Engineering Surveying





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Question 3


(a
)

A detail survey is to be ca
rried out at a scale of 1 in 10
0
. If plan
positions for this surv
ey are to be plotted with an accuracy of


0.3 mm,
with what precision would you record distances for this survey?


At this scale, with what precision would you attempt to record spot
heights?










(4 marks)


(b
)

Explain why it is preferable to plot su
rvey drawings on film instead of
paper.










(3

marks)


(c
)

For a detail survey, explain what is meant by the terms
hard detail

and
soft detail
, giving examples of each.









(4 marks)


(d
)

Describe the radiation method used in surveying for locatin
g detail.










(4 marks)


(e
)

During a detail survey, the following readings were obtained with a total
station set up at control station A:



Slope distance to point P


36.584 m


Vertical angle to point P


02˚47΄12
˝


Height of station A



12.365 m


Height of instrument



1.523 m


Height of reflector



1.625 m



Calculate the height of point P.










(5 marks)


CN106 Engineering Surveying





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Question
4


(a)

The horizontal

circle readings sho
wn below were taken using a total
station

tha
t has been correctly set up and levelled above point
A


___________________________________
____

Face


Point sighted



Horizontal







circle reading








° ′ ″



__________________________________
_____






FL




W




02 17

16




FL



X



137
52 20




FL



Y



209 22
37




FL



Z



312 14 50




FR



Z



132 15 01




FR



Y




29 22 48




FR



X



317 52 33




FR



W



182 17 29

_________
___________
___________________


Book the readings in a suitable format and calculate values for the
observed horizontal

angles.










(10

marks)


(b)

When me
asuring angles with a total station
, it is always advisable to
take the mean of face left and fa
ce right readings and to take two
rounds.


Discuss the reasons for this.










(3 marks)

(c)

You have just completed measuring all of the angles for a traverse
which has seven stations. If the total station you have been using has
an accuracy of 5" but
the weather conditions in w
hich you measured
the angles were

poor, what is the allowable error for the sum of the
angles

in this traverse
?















(3

marks)


(d)

Explain how parallax occurs and describe a proced
ure for removing it
from a total statio
n
.










(4 marks)

CN106 Engineering Surveying





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Question 5


The measured angles and
horizontal
lengths of
a traverse are shown in
Figure Q5

below.






















Figure Q5




The coordinates of station Q are 250.000 m
E, 250.000 mN and the bearing
QR is 93

47'50"
.


(i
)

Calculate the adjusted coordinates of stations P, R and S
.












(15 marks)


(ii)

Would you accept this t
raverse for setting out? G
ive reasons for your
answe
r.










(5 marks)

P
S
R
Q
87
º
08'20"
111
º
47
'
40"
97
º
47
'
00"
63
º
16
'
20"
180.280 m
112.615 m
106.253 m
164.578 m
CN106 Engineering Surveying





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CN106 Engineering Surveying


FORMULA SHEET









90
4
2
n
angles


2
2
3
2
2
2
2
1
1
1
2
2
24
cos
)
(
)
(
)
(
)
(
2
)
cos
1
(
cos
4
360
tan
3
2
180
tan
1
tan
cos
sin
F
S
F
S
F
B
F
B
N
E
N
E
T
L
corr
sag
t
t
L
corr
temp
E
A
T
T
L
corr
tension
l
l
l
L
l
l
l
L
corr
stand
L
h
L
corr
slope
L
D
N
E
D
quadrant
th
N
E
quadrants
rd
and
nd
N
E
quadrant
st
N
E
e
L
D
N
e
L
D
E
e
e
e
D
N
D
E
































































Young’s Modulus for steel


= 2 x 10
5

N mm
-
2

CN106 Engineering Surveying





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Coefficient of thermal expansion for steel


= 11 x 10
-
6

per

C





tan
sin
D
L
V
h
V
h
RL
Level
duced
Re
r
i
P
X









e

= (
s
1



s
2
)


(
s
3



s
4
) per
L

m


)
1
(
2




n
v
x
error
standard

)
1
(
2




n
n
v
x
error
standard


2
2
2
1
/
s
s
difference
sum
error
dard
stan





n
n
n
w
w
w
s
w
s
w
s
w
mean
weighted









2
1
2
2
1
1