profile leveling 2

7/28/2019 Profile Leveling 2

1/20

PROFILE LEVELING


2/20

It is the leveling operation is to determine the

undulations of ground surface along a predetermined

line.

Primary use is for utilities:

A. Highways

B. Canals

C. Sewers

D. SidewalksE. Retaining walls

F. Water mains

G. Fences

All of these need accurate

information about thetopography along the

route.


3/20

3

It is a common practice to use a procedure called stationing.1. Stations are established at uniform distances along the route.

2. Standard station distance is 100 feet.

3. Half or quarter stations are used when the topography is very

variable.

4. The distance from the starting point to the station is used as the

station identification.


4/20

Bench Mark:

it is the point mark from

Which we start our work

of known elevation. It

may be permanent ortemporary.

IN Pakistan almost

mean sea level is taken

as a bench mark butany arbitrary point can

be taken


5/20

BACK SIGHT

It is the staff rod

reading taken on a

point ofKnown elevation as

on B.M or change

point and it is the

first staff readingtaken after the level

is set up.


6/20

HEIGHT OF INSTRUMENT

It is the R.L of plane of collimation whenThe instrument is correctly level

H.I = R.L/B.M+B.S


7/20

INTERMEDIATE SIGHT

It is the staff reading reading taken on the

Point of unknown elevation from the same

Of level


8/20

FORE SIGHT

It is the reading of staff rod on a point whose

Elevation is to be determined as on a change

Point. It is the last staff reading of level at

A same place.


9/20

PROFILE DATA TABLE

9

STA BS HI FS I.S ELEV


10/20

EXAMPLE

10

We take this rod for our leveling work

Step one: establish the standard stations.

Note: the last station (745.1) is established even though it

is not a standard station.


11/20

EXAMPLE.

11

Step 2: Determine the sites for the critical features.

In this example, the critical features are the rapid change is slope at

337.5 and the road at 489.6.

Note a stations were established at 489.6 and 546.4to define the width of the road and any changes in

elevation across the road.


12/20

EXAMPLE

12

Step 3: Set up the instrument and start recording data.

The first rod reading is a backsight on the first sidewalk (benchmark)

to establish the height of the instrument.

Note: in this case the true elevation of the benchmark is unknown,therefore 100.00 feet is used.


13/20

EXAMPLE ONE DATA TABLE

13

STA BS HI FS I.S ELEV

0.0 10.5 110.5 100.00


14/20

EXAMPLE

Step 4: Start recording the rod readings for each station.

14

Note: station 100 is not used as a benchmark or as a turning point,

therefore it is an intermediate foresight.


15/20

EXAMPLE DATA TABLE

15

STA BS HI FS IS ELEV

0.0 10.5 110.5 100.0

100 6.3 104.2


16/20

EXAMPLE

The rod reading for each station is recorded on the appropriate line of the table.

16

STA BS HI FS IFS ELEV

0.0 10.5 110.5 100.0

100 6.3 104.2

200 3.9 106.6

300 4.1 106.4

337.5 7.4 103.1

400 9.2 101.3

489.6 8.0 102.5

Note: the rod reading for station 489.6 is placed in the FS column

because this station will be used as a turning point.


17/20

Step 6: the instrument is moved so the remaining stations can bereached.

17

STA BS HI FS IFS ELEV0.0 10.5 110.5 100.0

100 6.3 104.2

200 3.9 106.6

300 4.1 106.4

337.5 7.4 103.1

400 9.2 101.3

489.6 6.6 109.1 8.0 102.5

500 6.7 102.5546.4 6.8 102.2

600 4.9 104.2

700 2.2 106.9

745.1 1.5 107.6


18/20

Sidewalk Profile

100.0

104.2

106.4

103.1

101.3

102.5102.3

104.2

106.9

107.6

102.4

106.6

99.5

100.0

100.5

101.0

101.5

102.0

102.5

103.0

103.5

104.0

104.5

105.0

105.5

106.0

106.5

107.0

107.5

108.0

0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750

Distance


19/20


20/20

profile leveling 2

Documents