TBM

1
Approximate North
Main Gate
TBM 9.09 m A.A.D.
Burnaby Building
Top of door level at entrance to structures
laboratory
Ground level at entrance to structures laboratory
TBM 10.00 m A.A.D.
Point 1
Start at a TBM outside the main entrance of
Burnaby Building and obtain the RL values of
three points before closing onto another TBM near
the main gate.
2
Burnaby Building
L 52
07/10/98
M.A.R.
M.A.R.
Good
TBM 10.00m AAD
It is important to complete details at the top of
booking forms or on every page of field books.
3
Key
BS
Level Posn.
TBM
4
10.000
1.546
11.546
HPC RL BS
HPC 10.000 1.546 11.546
We now signal to the staff person to move to the
next point.
As the next required point is too far away (it is
also round a corner) we will eventually need to
move the instrument.
So, we must move the staff to a change point
(CP), to allow us to move the instrument to a
better position later on.
5
Key
BS
FS
CP
Level Posn.
TBM
6
New staff position therefore a new row. Each
row represents a staff position.
C.P.
1.562
9.984
RL HPC - FS
RL 11.546 - 1.562 9.984
After we make a FS and we have calculated the new
RL we are finished with that instrument position.
Move the Instrument (about the CP) to a new
position where we can see the CP and also the
next point we want the RL value of.
7
Key
IS
BS
FS
CP
Level Posn.
TBM
8
Same staff position as last reading therefore
the same row
1.418
11.402
HPC RL BS
HPC 9.984 1.418 11.402
9
Key
IS
BS
FS
CP
Level Posn.
TBM
This reading is not the first so it is not a BS
It is not the last from this position (we can see
the next points) so it is not a FS
So it is known as an INTERMEDIATE SIGHT (IS)
10
New staff position therefore a new row
1.390
10.012
Point 1
RL HPC - IS
RL 11.402 - 1.390 10.012
11
Key
IS
BS
FS
CP
Level Posn.
TBM
12
New staff position therefore a new row
GL Struct. Lab Door
1.281
10.121
RL HPC - IS
RL 11.402 - 1.281 10.121
13
Key
IS
BS
FS
CP
Level Posn.
TBM
14
New staff position therefore a new row
Top Struct. Lab Door
-2.420
13.822
Requires an inverted staff
i.e turn the staff upside down
Read and then book the staff with a negative sign
The negative sign will keep all the calculations
correct
RL HPC - IS
RL 11.402 - (-2.420) 11.402 2.420
13.822
15
Key
IS
BS
FS
CP
Level Posn.
TBM
The last point required is the TBM. However it is
too long a sight.
So we need a CP. This will be the last sighting
from this position
Therefore a FS
16
New staff position therefore a new row
CP
1.321
10.081
RL HPC - FS
RL 11.402 - 1.321 10.081
Last Reading -- FS -- Move the instrument
17
Key
IS
BS
FS
CP
Level Posn.
TBM
18
1.011
11.092
Same staff position as last reading therefore
the same row
HPC RL BS
HPC 10.081 1.011 11.092
19
Key
IS
BS
FS
CP
Level Posn.
TBM
20
TBM 9.09m AAD
2.009
9.083
New staff position therefore a new row
RL HPC - FS
RL 11.092 - 2.009 9.083
21
Before we look more fully at the results we will
complete the
second half of the levelling exercise
Key
IS
BS
FS
CP
Level Posn.
TBM
22
Top of door level at entrance to structures
laboratory
Ground level at entrance to structures laboratory
Point 2
Key
IS
BS
FS
CP
Level Posn.
TBM
23
Key
IS
BS
FS
CP
Level Posn.
TBM
24
Key
IS
BS
FS
CP
Level Posn.
TBM
25
Key
IS
BS
FS
CP
Level Posn.
TBM
26
Key
IS
BS
FS
CP
Level Posn.
TBM
27
Key
IS
BS
FS
CP
Level Posn.
TBM
28
Key
IS
BS
FS
CP
Level Posn.
TBM
29
Key
IS
BS
FS
CP
Level Posn.
TBM
30
Key
IS
BS
FS
CP
Level Posn.
TBM
31
Key
IS
BS
FS
CP
Level Posn.
TBM