FAR WESTERN UNIVERSITY

SCHOOL OF ENGINEERING

SURVEY CAMP PRESENTATION

GROUP 3

1
 Major
Traverse
TRAVERSE

• Traverse refers to series of connected survey lines which

form the framework
• directions and lengths of the survey lines are measured
using theodolite and tape or using total station).

On the basis of nature,Traverse can be categorized as:

 Major Traverse
 Minor traverse
Major traverse
• Used for larger area
• It is done for establishing control points

Field works
Field works involved in major traverse are given below:
1. Reconnaissance
o Inspection and examination of the entire area
o It is done for selecting suitable location for control points
and to gather information about detail points ,
undulations, ground condition etc.
2. Selection of traverse station:

The criteria for selection of control station includes

accessibility of the station

visibility between stations

stability of the ground

availability of suitable reference points.

To avoid straight lines , angle
Leg ratio should not exceed
between 180ο±20” are
2:1 (max : min)
avoided

3. Marking and referencing of stations:

• Stations should be marked by driving wooden pegs/iron
nails/concrete pillars etc.
• Referencing of stations should be done in permanent points. At
least 3 points should be taken from each station Y Shape .
• Distance should be measured.
fig: Referencing
 4. Field measurement:
It involve linear and angular measurement. Linear measurement is
done using tape or chain or total station. Similarly , angular
measurement can be done using theodolite or total station.

Linear measurement accuracy is 1:5000 for total station.

5.Angular measurement:
• Two set reading i.e. 0 set and 90 set of HCR should be taken for
precise measurement of angle.
• The difference between FL and FR reading should be within ±20”.
• The difference between 2 set reading should be under 1’.
Traverse computation

For included angle traverse,

 Sum of all the traverse angle= (2n±4)*90̊ (+ for exterior angle
and – for interior angle)
If Sum(practical)ǂ Sum(theoretical), then
Error(e)=Observed sum- theoretical sum
Permissible limit = 30”√n

 If error is within limit, then correction can be done with

opposite sign by arbitrary method according to field
condition. The error is distributed to each station by dividing
the error by no. of stations.
i.e. Correction in each angle = ±error/no. of stations
Calculation of bearing:
Bearing of one leg is either given or calculated from the co-
ordinates of first two station given. Bearing of other leg are
calculated as:
Fore bearing of next line= (FB of previous line+ clockwise angle
at that point) ±180 or -540
 +180 if sum<180
 -180 if sum is >180
 -540 if sum>540
Calculation of latitude and departure:
Latitude is the co-ordinate distance measured parallel to the
reference meridian.
Latitude (L)= lcos(bearing) , where l is the leg length

Departure is the distance measured

perpendicular to the reference meridian.
Departure(D) = lsin(bearing)

For a closed traverse :

∑L=0
∑D=0
 If there is closing error,
Error(e)= √∆L2+∆D2
Precision= 1:5000 (error/perimeter)

Closing error can be balanced by either Bowditch’s or Transit’s

rule.
Correction using Bowditch’s rule is done as below:
For latitude:
Correction in latitude=∆L*Li/∑Li
For departure:
Correction in departure=∆D*Li/∑Li
Where Li =length of that line and ∑Li = Total length
Computation of independent co-ordinate

• coordinates of any point with respect to a common origin

• Origin point may be station point of traverse or it may be
outside the traverse.
Independent co-ordinate of any point= Origin co-ordinate +
algebraic sum of all correlated latitude or departure upto that
point
(sum of latitude for northing and departure for easting)
Calculation of adjusted length and bearing:

Adjusted length=√(xB-xA)2+(yB-yA)2

Adjusted bearing= tan-1((xB-xA)/(yB-yA))

Where xB and xA are latitude of

station B and A respectively and
yB and ya are northing of
station B and A respectively.
Fig: Plotting of Major traverse
 LEVELLING
 Levelling is defined as the branch of surveying which
deals in finding the elevations of the given points with
respect to a given or an assumed datum.

Objective of levelling:
 Estimation and design of numerous civil engineering
projects, including roads, bridges, canals, etc.
 To survey routes and alignment of highways, bridges etc.
 For the purpose of earthwork, including cut and fill.

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 DAY 5

Two peg test:

 To find out the collimation error.
In first fig,
h1=∣a1​−b1∣

In second fig,
h2=∣a2​−b2∣

Error=∣h1​−h2∣

Precision=1/10000

Accuracy=1/(length/error)

 Precision was 10666.67

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 Points to be considered during fly levelling:

 Avoid reading below 0.6m and above 2m to minimize

error due to refraction of light and non-verticality of
staff.

 Balancing of sight.

 Three wire reading to eliminate the personal errors.

 Use of turning plate at turnings.

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Fly levelling and loop levelling:

 Transfer RL from BM of known RL to unknown RL Using auto level.

 Two close loop are formed using TBM and PBM.

 RL is checked at every TBM.

 Given RL of BM= 205m, Calculated RL at BM=204.995m

 Closing error = ± 24√K mm, K = distance in km

Error =5mm (limit=16.4868mm) 19
 Table For Forward Direction (From PBM to TBM)
BS FS

Elevation Hz. Distance

S No. Mean BS S1 Mean FS S2 Rise Fall Remark
(m) (m) S*100
T M B T M B

1. 1.483 1.421 1.359 1.421 0.124 205.000 0.124 12.400 PBM

2. 1.316 1.245 1.175 1.245 0.141 1.386 1.381 1.250 1.339 0.136 0.082 205.082 0.277 27.700
3. 1.798 1.731 1.662 1.730 0.136 1.222 1.155 1.089 1.155 0.133 0.09 205.172 0.269 26.900
4. 1.835 1.787 1.741 1.788 0.094 0.891 0.823 0.755 0.823 0.136 0.907333 206.079 0.230 23.000
5. 1.335 1.283 1.230 1.283 0.105 0.717 0.664 0.610 0.664 0.107 1.124 207.203 0.212 21.200
6. 1.676 1.644 1.612 1.644 0.064 0.871 0.820 0.768 0.820 0.103 0.463 207.666 0.167 16.700
7. 1.892 1.840 1.786 1.839 0.106 0.917 0.885 0.853 0.885 0.064 0.759 208.425 0.170 17.000
8. 1.889 1.827 1.764 1.827 0.125 0.812 0.761 0.711 0.761 0.101 1.078 209.503 0.226 22.600

9. 1.406 1.336 1.266 1.336 0.140 1.128 1.069 1.011 1.069 0.117 0.757333 210.261 0.257 25.700

10. 1.356 1.311 1.266 1.311 0.090 0.972 0.902 0.833 0.902 0.139 0.433667 210.694 0.229 22.900

11. 0.732 0.671 0.611 0.671 0.121 1.155 1.108 1.060 1.108 0.095 210.898 0.216 21.600 TBM
0.203333

SUM 1.645 1.588 1.532 1.588 0.113 0.917 209.981 0.113

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237.700
Bridge Site Survey
Introduction

 A bridge site survey is a

comprehensive examination and
analysis of a specific location
where a bridge is proposed to be
constructed.
Objectives

• To select the possible bridge site and

axis for the construction of bridge.
• To collect the preliminary data i.e.
normal water flow level, high flood
level.
• To study about the geological features
of the ground.
• To carry out surveying for topographical
mapping, longitudinal and cross
sections at both the upstream and
downstream side of the river.
 Methodology

Levelling
Fixing of control
Bridge axis •Fly levelling
Reconnaissance points and Detailing
selection •Reciprocal
triangulation levelling
Reconnaissance

In this stage, visual

inspection of the site
is done and
information about
topographical and
geological features of
the site are collected
Bridge axis selection

• There should be uniform & steady flow in

the reach.
• The river banks should be stable.
• The width of the river channel should be
minimum.
• The site should be sufficiently away from
the confluence point.
Fixing of control points and
Triangulation

 Thebridge axis was set and horizontal

control stations were fixed on either side.
 Forthe topographic survey of bridge site,
triangulation was done.
 Triangulationis the process of measuring
the angles of a chain or a network.
 The main purpose of the triangulation was to determine
the length of the bridge axis. The triangulation also serves
the control points for detailing.
 Triangle should be well conditioned i.e.(between 30 and
120 degree)
 Distances between stations on the same sides of river i.e.
base lines were measured with tape precisely.(with
accuracy of 1:2000)
 Angles of the base triangle were measured using
theodolite with two sets of reading.
 The bridge axis length or span was calculated by solving
the triangles using the sine rule.
 The bearing of the bridge axis was measured using
compass.
 For vertical control, the level was transferred from the
given arbitrary benchmark and RL was transferred to the
stations on the next bank by reciprocal leveling while
direct level transfer method was used or the same bank.
Levelling

 Fly levelling was conducted to transfer R.l from given B.M to control station
and from control station to other triangular station of same side.
 Reciprocal levelling was done to transfer R.L from control station of one bank
to another.
Detailing

Readings are taken from

the triangulation station
150m upstrem and 50m
downstream from the
bridge axis at 25m
interval.
Contour map
 Road Alignment

 Introduction
 It’s requirements
 Factors Controlling Alignment
 Technical Specifications(Norms)
 Methodology
 Curve Setting
 Field Procedure
 Conclusion
Introduction

 The position or layout of center line of the highway on the ground.

 It includes horizontal and vertical alignment.
 Preliminary stage of road construction.
 Requirements
The requirements of an ideal alignment are:

 Short
 Easy
 Safe
 Economical
Factors Controlling Alignment

 Obligatory Points
 Traffic
 Economics
 Other Considerations
Technical Specifications

 Alignment selection of a road corridor about 500 to 700 m or more.

 Deflection angle should be less than 90°.
 Adjacent intersection points(IP) must be inter-visible.
 Horizontal curves had to be laid out where the road changed its direction.
 Radius of the curve should not be less than 90°.
 Gradient between IPs should be ≤ 12 % of existing ground surface.
 Subsequent reverse curve should be avoided.
 Two successive curve must not be overlapped.
Formula to compute the Road’s Hz. Curve Elements during field
survey

 Tangent length= R( Tan∆/2 )

 Length of circular curve = ( ∏R∆/180 )
 Apex distance (E) = R( (1/cos∆/2) – 1)
 Chainage of IP =Chainage of previous EC + ( IP to IP distance-
previous tangent length )
 Chainage of BC or T1 = Chainage of current IP – current tangent
length
 Chainage of MC = Chainage of BC + ( length of curve/2 )
 Chainage of EC or T2 = chainage of BC + length of curve
 Direction of MC = interior angle /2
Methodology:
I. Map study
II. Reconnaissance survey
III. Preliminary survey
IV. Final Location and Detailed survey
Setting out of simple
circular curve
In our road alignment survey, we
used Rankine’s Method for
setting out of curve.
Simple circular curve:
Tangential to both the straight
line.
Transition curve: Curve of
varying radius introduced
between a straight line and
circular curve.
 Field Procedure:
 Choose the distance from CP1 for alignment of road and mark the IP1.
 The theodolite inst. is set at IP1 and set zero along CP1 then rotate theodolite along IP2 and
measure internal angle by intersecting ranging rod.
 Through interior angle, calculate the deflection angle by using: deflection angle = 180° -
observed angle
 By using deflection angle; calculate tangent length, apex distance, length of curve, BC, MC and EC.
 Then set BC, EC and MC on the field.
 To set the middle of curve, bisect the interior angle with the help of theodolite and use apex
distance obtained through calculation.
 Repeat the same process at each IP stations.
 Finally, compute the chainage length.
 Then carry out levelling survey for longitudinal section along the centerline at 15 m interval.
 Cross sections had to be taken at 15 min intervals and at BC, MC and EC of curve. Coverage width of
c/s must not be ≤ 10 m on either side.
Plan of the Road:
 Conclusion:

 It helps to collect details of topography, drainage and soil.

 L – section is useful for determining inclination while passing from one point
to another.
 Cross – section of road is useful to estimate the quantity of earthwork.
 To finalize the best alignment.
Profile Levelling,
Cross Sectioning
and Reciprocal
Levelling
1. Profile Levelling ( Longitudinal Levelling)
Profile levelling is the process of levelling along a fixed line to determine the
elevations of the ground surface along the line.

2. Cross Sectioning Levelling

Cross Sectioning Levelling is the process of levelling which defines the
profile view of the ground perpendicular to the center line or base line and
indicate ground elevations at points of change in the ground slope i.e.
ground may be straight, steep, elevated, etc.
Purpose of Profile Levelling

A. The purpose of profile levelling is to provide data from which the depth of
fill or cut required to bring existing surface up to, or down to, the grade
elevation required for the highway can be determined.

B. To design linear facilities such as highway, railway, transmission lines,

canals, sewers and water mains, engineers need accurate information about the
topography along the proposed route; profile levelling which needs elevation at
definite points along a reference line, provides the needed data.
3. Reciprocal Levelling

Reciprocal levelling is a surveying method which is applied to find the difference

in elevation between two faraway point; the observations are fraught with errors.

It is adopted to accurately determine the level difference between two points which
are separated by obstacles like a river, ponds , lakes, etc.

In this method, Errors may arise out of the curvature of the Earth or intervening
atmosphere (associated with variation in temperature and refraction ) or instrument (
due to error in collination ).
 It is done by:
I. By HI method
II. By rise and fall method

Fig: Reciprocal Levelling