chain-and-tape-survey. using and important

Chain & tape survey

1. SURVEYING
Ch. 2 Chain and Tape
Survey

2. 2.1 Linear measurement
Methods
ElectronicmethodsBy optical meansDirect measurements

3. Chain Survey
Chain survey is the easiest type of survey in which area to be surveyed is
divided into a number of triangles.
Because all the geometrical figures only whose shape and size are
determined when the length of the sides are known.
The perpendicular distance, called offsets, of various objects in the field
from the line, are measured and recorded in a book called field book.
From this records in the field book, the whole area can be plotted on a
drawing sheet to a reduced scale.

4. 2.1 Instruments for chaining/taping
Chain/tape
Arrows
pegs
Ranging rods
Plumb bob
Hand level

5. 2.1 Instruments for chaining/taping
Pegs
1. Station position
2. Terminal points of survey line
Ranging rods
1.Used to range intermediate points on survey line
2.Length 2 m ( very common) or 3 m
3.Bands of 20 cm painted alternate colour( red & white, black & white)
Ranging poles
1.Similar to ranging rod but big in size
2.Used in case of long lines
3.Used to range intermediate points on survey line
Plumb bob
1.Verticality of ranging pole
2.Transferring the points to ground
3.Also used for centring purpose in other surveying methods.

6. 2.2 Different types of chain/tape
Chain (Absolute equipment at present)
–Metric chain (available in 5,10,20 meter) In a metric, a small brass ring is
given in every one-meter interval. Brass tallies are also given at each 5.0 m
length of the chain. Every tally has a complex shape which indicates 5, 10,
15m from any one side of the chain. However, metric chains are prepared
in 20 m and 30 m length.
–Gunter’s or surveyor’s chain (66 ft of 100 links)
–Engineer’s chain (100 ft of 100 links) The Engineers chain is 100 ft, long and
Gunter's chain 66 ft. The Engineer's chain consists of 100 links each one a
foot long and at every 10 links a tally is attached to facilitate reading. The
Gunter's chain is also divided into 100 links each link is 7.92 inches.
–Revenue chain (33 ft of 16 links)
–Steel band or band chain ( 20 or 30 m)

7. 1.Metricchain 2.Revenuechain
4.Engineer’schain3.Gunter’schain

8. 2.3 Ranging out of survey lines
•When the length of survey line is greater than chain or tape
length
–Process of establishing intermediate points
•Methods
–Direct Ranging
–Indirect Ranging
25 November 08 Unit 2 :Chain Surveying
A
B
> one tape length
Intermediate points

9. 2.3 Direct ranging
•Direct ranging
–When two end points are intervisible
–Either by eye or through optical instruments such
as
•Line ranger
•Theodolite
–Code of signals used to direct assistant
25 November 08 Unit 2 :Chain Surveying
A
P
B
Transverse movement
< one tape length

10. 2.3 Indirect ranging
•Indirect ranging
–When two end points are not intervisible
–With the aid of two intermediate points very near
to the line
25 November 08 Unit 2 :Chain Surveying
A
B
N
M
B
A
M N
N
3
N
2
M
2
N
1
M
3
M
1

11. 2.3 Chaining/taping over sloping
ground
•Methods
–Direct method or method of stepping
–Indirect method
With the aid of vertical angle measurement
With the aid of difference in level measurement
Hypotenusal allowance
25 November 08 Unit 2 :Chain Surveying

12. 2.3 Chaining/taping over sloping
ground
•Direct method or stepping method
–Convenient to proceed down-hill
–Tape shall be horizontal
–Sufficient pull to avoid sag
–Lengths of steps inversely proportion to degree of slopes.
25 November 08 Unit 2 :Chain Surveying
A
l
4
l
3
l
2
l
1
D = (l
1+l
2+l
3+l
4)

13. 2.3 Chaining/taping over sloping
ground
•Indirect method (Vertical angle measured)
–Clinometer to measure vertical angle
25 November 08 Unit 2 :Chain Surveying
D1 = s1×cosΦ1
The required horizontal distance (D) =∑s cosΦ
D2
Φ1
Φ2
s1
s2
C
B
A
D1
Contd….
Indirect method (difference in height)
Level machine is used
to measure h to compute D.
D = √( s
2
-h
2
)
D
h
s
A
BC
Indirect method (Hypotensual allowance)
B
A’
C
A
θ
1 chain
BA
/
= BC = 1 CHAIN
BA = 1 CHAIN ×sec θ
AA
/
= BA-BA
/
= 1 CHAIN ( sec θ–1)

14. 2.4 Chain surveying
•What is chain surveying?
•Principle of chain surveying
–Triangulation
25 November 08 Unit 2 :Chain Surveying
Survey stations
Main station (A, B, C,…E)
Subsidiary stations (F, G, H)
Marking of stations
Survey lines
Main survey lines
Base lines
Check lines
Tie lines

15. 2.4 Survey stations & survey lines
•Station
–Mutually visible
•Survey lines
–Few as far as possible
–Must have one base line
–Pass through level ground
–Form well-conditioned triangle
–Sufficient check line
•Short offset
•Should not pass through obstacle
•Should fall within the boundaries
25 November 08 Unit 2 :Chain Surveying

16. 2.4 Locating the ground features
•Offsets-lateral distance of an object from
survey line.
•Offsets should be as small as possible
•Types
–Perpendicular –less measuring on ground
–Oblique
–Method of ties
25 November 08 Unit 2 :Chain Surveying
P
Q
A
C
P
B
90
0
B
A
P
C
≠ 90
0

17. 2.4 Locating the ground features
•Swing of the tape on chain line
•Shortest distance is
perpendicular offset
25 November 08 Unit 2 :Chain Surveying
P
Contd….

18. 2.4 Locating the ground features
•Offsets are taken in the
order of their chaninage.
•Number of offsets
depends upon the shape
of objects
–Straight wall, zigzag wall,
road with constant width
25 November 08 Unit 2 :Chain Surveying
Constant width road
Boundary wall
Contd….

19. 2.4 Locating the ground features
25 November 08 Unit 2 :Chain Surveying
Contd….

20. 2.5 Chain surveying (field/office work)
•Equipment
–Chain/Tape (>30 m)
–10 Arrows
–Raging rods
–A tape ( 10 m or 20 m )
–Cross staff or Optical square
–Field book, pencil
–Plumb bob
–Pegs, wooden hammer, chalks
25 November 08 Unit 2 :Chain Surveying

21. 2.5 Field work
•Field work consists of three steps
–Reconnaissance
–Marking and fixing survey stations
–Running survey lines
25 November 08 Unit 2 :Chain Surveying
Reconnaissance
Walkover survey with the view of principle of
surveying
Reference sketch
Thinking of possible problem and their solution in
actual survey

22. 2.5 Field work
•Purpose is to enable to locate stations
during progress of work
•Wooden pegs in soft ground
•Nails or spikes in hard surface (road) &
flushed with pavement
•For a long time used station, a stone of
standard size fixed with mortar
•Reference of two or three permanent
object
25 November 08 Unit 2 :Chain Surveying
Chaupari
Building
Electric pole
9.65m
10.50m
9.90m
Contd….

23. 2.5 Field work
•Start chaining from base line
•Consists of two folds
–Chain the survey line
–Locate the adjacent details
25 November 08 Unit 2 :Chain Surveying
Building
Chaupari
One tape length
Contd….

24. 2.5 Field work
25 November 08 Unit 2 :Chain Surveying
Contd….

25. 2.5 Office work
•Part of office work
•Computation of data
•Plotting work
–Size of paper should be
standard (in mm)
•A0 = 840 * 1188
•A1 = 594 * 840
•A2 = 594 * 420
•A3 = 420 * 297
•A4 = 297 * 210
25 November 08 Unit 2 :Chain Surveying

26. 2.5 Plotting work
•Fix the scale of survey before starting
–Purpose of survey
–Extent of survey
–Finance available
•North upward rule
•Nice lettering (Always in the drawing)
•Skeleton first then offsets
–Use of tracing paper for proper
orientation
25 November 08 Unit 2 :Chain Surveying

27. 2.5 Plotting work
•Start with base line
•Triangles are laid by intersection of
arcs
•Verification of check lines
•Offsets are then plotted by
–Set square or
–Offset scale
•Ground features representation with
symbol
•Title box and legend box
•Use of HB, 2H and 3H pencils
25 November 08 Unit 2 :Chain Surveying

28. Conventional symbols
25 November 08 Unit 2 :Chain Surveying

29. Conventional symbols
25 November 08 Unit 2 :Chain Surveying
Contd….