Survey Camp Report (Mars Nepal Engineering Survey Camp)

Date of Submission:- 2080/12/05
PURBANCHAL UNIVERSITY
ARYAN SCHOOL OF ENGINEERING AND MANAGEMENT
MID BANESHWOR, KATHMANDU
DEPARTMENT OF CIVIL ENGINEERING
A FIELD REPORT OF “SURVEY CAMP 2080”
(BCE III/I ) - 2020 BATCH TO
MARS NEPAL ENGINEERING SURVEY CAMP PVT. LTD.
BUNGMATI, KARYABINAYAK
GROUP NO. :- 04
Submitted By :- Submitted To :-
Sudip Khadka (2020BCE1138)
Suman Dhungana (2020BCE1139)
Sushil Kumar Sah (2020BCE1141)
Susma Katwal (2020BCE1142)
Mahesh Kumar Sah (2020BCE1116)
Binod Kumar Kapair (2020BCE1106)
Department of Civil Engineering
Survey Instruction Committee
Mid-Baneshwor, Kathmandu

PURBANCHAL UNIVERSITY
ARYAN SCHOOL OF ENGINEERING AND MANAGEMENT
MID BANESHWOR, KATHMANDU
DEPARTMENT OF CIVIL ENGINEERING
Date:- 2080/12/05
APPROVAL SHEET
This is certify for the completion of survey close camp of 5th
semester (B.E. in Civil
Engineering) 2020 Batch, organized by Aryan School of Engineering and Management in
partial fulfillment of the requirements for the Degree of Bachelor of Engineering.
B.E. Survey Camp 2080
Group No :- 4
NAME OF THE STUDENTS ROLL NO.
SUDIP KHADKA (2020-BCE-1138)
SUMAN DHUNGANA (2020-BCE-1139)
SUSHIL KUMAR SAH (2020-BCE-1141)
SUSMA KATWAL (2020-BCE-1142)
MAHESH KUMAR SAH (2020-BCE-1116)
BINOD KUMAR KAPAIR (2020-BCE-1106)
…..…….…….…… ….………..……..…
External Examiner Er. Abhash Acharya
Head of Department
Department of Civil Engineering

i
PREFACE
This survey camp report is truly based on our knowledge gained from the two weeks
of fieldwork conducted by the Survey Instruction Committee, Aryan Engineering
College for the partial fulfillment of the requirement for the Bachelor’s Degree in
Civil Engineering as per the syllabus of, Purbanchal University in the third year first
part. The Materials in this report are the outcomes of the unbelievable works of each
and every member of Group 4, who gave their valuable time and knowledge for this
report. This report is compilation of great efforts from the group members.
This surveying has been able impart us the great opportunity to consolidate and
review the practical and theoretical knowledge on surveying, which we gained in the
second year. This survey camp has also helped in the team coordination for the long-
term teamwork in the friendly environments. This practice of teamwork is a great
achievement for future professional work in practical life. This survey camp also
developed a sense of individual responsibility towards the steps taken by the group.
We have been able to achieve the true objectives of the survey and upgrade our
knowledge in handling of the instrument, working procedure, problem-solving, and
field booking precisely. This survey camp gave us the practical knowledge of
overcoming the technical difficulties and developing skill in tackling it. It encouraged
us to cope with the team members, as the surveying involved all the members equally
during the field procedures, calculations and plotting and report preparations.
Every effort has been taken to ensure the accuracy in this report. However some
errors might have occurred. We will be very much grateful to the viewers who go
through this report for bringing such errors in our notice. Furthermore we would be
very thankful for the examiners or viewers for their suggestions in improving this
report.
In conclusion, those 12 days were very much fruitful days and we are sure that these
learning and experiences gained during the camp period as a real field engineer will
help us for shaping our future career as Civil Engineer.
With Regards,
Group – 4
Survey Camp 2080
Aryan Engineering College

ii
ACKNOWLEDGEMENT
We would like to express our sincere gratitude to the Department of Civil
Engineering, Aryan School of Engineering and Management, Purbanchal
University, and the Survey Instruction Committee for initiating and facilitating the
survey camp to enhance our knowledge of surveying and its applications.
The purpose of this fieldwork was to make the each student independent to carry out
the work in real problem in the field. As a team, we were really curious and motivated
to learn and implement the theoretical knowledge into the practical field. This would
not have been possible without the unconditional support and guidance from our
respected teachers and instructors. .
We express my sincere gratitude to Er. Dev Raj Joshi, Principal of Aryan School of
Engineering and Management, Er. Abhash Acharya, Head of Civil Engineering
Department, for their kind help and assistance.
We are also indebted to our Coordinator of Survey Instruction Committee and course
instructor Er. Arjun Gautam & Er. Prasanna Adhikari for their helpful
suggestions, friendly behavior, guiding any time during the field work and
supervising in every aspect of our study. Without his help, this study would probably
be impossible.
We would like to respect the store keeper, Er. Haribansh Kumar Chaudhary the
entire instrument and store personnel who co-operated with me in the matter of
guidance to providing instruments when needed.
We put our sincere thanks to our friends and colleagues for their support and help. We
would like to thank the college administration. We are also grateful to our parents
for their strong will in the success of ourpath and endless commitment for it.
Lastly, we would like to thank everyone who helped us directly or indirectly during
the duration of the survey camp and in the preparation of this report. Their effort and
sincerity on the field are always memorable to us.
Last but not the least, we are thankful to the host of survey camp, MARS Nepal
Engineering Survey Pvt. Ltd. for arranging and maintaining a safe and comfortable
environment to conduct our work smoothly and also for arranging such a pleasant stay
and all the canteen staffs for preparing delicious meals each and every day.
B.E. Survey Camp 2080
Group No. :- 4
Sudip Khadka (2020 BCE 1138)
Suman Dhungana (2020 BCE 1139)
Sushil Kumar Sah (2020 BCE 1141)
Sushma Katwal (2020 BCE 1142)
Mahesh Kumar Sah (2020 BCE 1116)
Binod Kumar Kapair (2020 BCE 1106)

iii
EXECUTIVE SUMMARY
Survey camp has been held keeping amid eye so as to make students used to
real scenario of field. Survey camp has enabled us to visualize the theoretical
knowledge in real working field. It assists not only for academic and subjective
practical improvement but also gives the space for students in time management,
team member’s coordination, behavior’s patience.
Surveying is the first step of execution of any project. It provides the valuable
information for the further works to be done like amount of materials needed, cost
estimation and many more. It helpsthe engineers and contractors to plan further action
to proceed forward.
The work of surveying is generally done by establishing control points. The main aim
of doing is to work from whole to parts which is one of the principles of surveying. This
also helps to collect data from the points which are not visible form a single point in
large area. While transferring the elevations from known point to unknown points,
temporary benchmarks are established at which loops are closed and data are checked.
If we talk collectively about the Survey camp, we encountered all forms of land
structures (i.e, level surface, constantinclined surface, difficult sloped zigzag way)
during fly-leveling. Then, talking about road survey which we also performed in
MARS Survey Camp area which made us aware with the selection of road
alignment and setting of geometric curves and collection of data necessary for
construction of the road were performed using the methodology: horizontal
alignment, leveling, longitudinal sectioning and cross section.
Similarly, bridge site survey was competed in a site where we faced all criteria
which can be probably present in context of Nepal such as dense hilly vegetation,
upstream and down stream’s steep slopes, adverse cold climate. The various method
performed during bridge site survey were triangulation, leveling, tacheometry,
cross-sectioning and L-sectioning.
After bridge site survey, topographic survey of given area, which is a compound
of the MARS Survey camp was performed. 75% work of traversing was
assumed to be completed after successful fixation ofcontrol points. In a nutshell,
we can make sub-loops using SBM. Axis length ofbridge is calculated out more
precisely. Two peg test is done to check auto level accuracy then RL of each
control points is determined. TS is used for better and fast for detailing, length
and angles of survey lines.

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WORKING SCHEDULE
Project Title:- Survey Camp 2080
Location:- Bungmati, Karyabinayak- 12, Lalitpur
Duration:- 13th
Kartik to 24th
Kartik (12 Days)
Working Time:- 8:00 a.m. to 5:00 p.m.
Class:- 8:00 p.m. to 9:30 p.m.
Surveyed By:- Group No. 4 (BCE III/I) 2020 Batch
S.N. Day Survey Field Work
1 13th
Kartik Reconnaissance, index sketch, selection of Major Traverse station, pegging
and Major Traverse observation
2 14th
Kartik Road Site Survey:- Selection of IP, Deflection angle observation, Two peg
test, Fly levelling, L-Section & X-Section observation at 5m,10m in both side
of road at every point with multiple of 15m
3 15th
Kartik Road Site Survey:- Selection of IP, Deflection angle observation, L-Section &
X-Section observation at 5m,10m in both side of road at every point with
multiple of 15m
4 16th
Kartik Road Site Survey:- Selection of IP, Deflection angle observation, L-Section &
X-Section observation at 5m,10m in both side of road at every point with
multiple of 15m
5 17th
Kartik Bridge Site Survey:- Bridge axis selection, Bridge site Triangulation, Angular
observation using Theodolite, Two way distance measurement by Taping
6 18th
Kartik Bridge Site Survey:- Fly leveling, Loop Levelling, Reciprocal Levelling,
Detailing(u/s 150m, d/s 50m) and Computation
7 19th
Kartik Topographic Survey:- Searching the peg, Angle and horizontal distance
measurement using Total station for Major traverse
8 20th
Kartik Topographic Survey:- Angle and horizontal distance measurement using Total
station for Major traverse
9 21th Kartik Topographic Survey:- Re-observation of Angle and horizontal distance
measurement for correct angle and precision, RL transfer from PBM to TBM
using Fly levelling considering three loops i.e. (PBM to SBM1, SBM1 to
SBM2, SBM2 to TBM)
10 22th Kartik Topographic Survey:- Fixing of minor station, Angle and horizontal distance
measurement using Total station for Minor traverse, RL transfer from TBM to
CP1 using Fly levelling & Loop Levelling from CP1 to CP2 including Minor
traverse station, Detailing and plotting
11 23th Kartik Instrumentation and viva, Detailing and Computation for Topographic survey
12 24th
Kartik Remaining work:- Detailing of area from two Minor traverse station

v
ABBREVIATIONS AND ACRONYMS
IP Intersection Point
RL Reduced Level
BM Bench Mark
TBM Temporary Bench Mark
PBM Permanent Bench Mark
SBM Site Bench Mark
MC Mid of Curve
EC Ending of Curve
BC Beginning of Curve
TL Tangent Length
LC Length of Curve
BS Back Sight
FS Fore Sight
IS Intermediate Sight
HCR Horizontal Circle Reading
VCR Vertical Circle Reading
WCB Whole Circle Bearing
HA Horizontal Angle
VA Vertical Angle
HI Height of Instrument
BB Back Bearing
FB Fore Bearing
HFL High Flood Level
NFL Normal Flood Level
RB Right Bank
LB Left Bank
RM River Mid
BA Bridge Axis
MSL Mean Sea Level

vi
TABLE OF CONTENTS
PREFACE.......................................................................................................................i
ACKNOWLEDGEMENT .............................................................................................ii
EXECUTIVE SUMMARY ......................................................................................... iii
WORKING SCHEDULE .............................................................................................iv
ABBREVIATIONS AND ACRONYMS......................................................................v
TABLE OF CONTENTS..............................................................................................vi
LIST OF FIGURES ......................................................................................................xi
CHAPTER 1 ..................................................................................................................1
INTRODUCTION .........................................................................................................1
1.1 Background..............................................................................................................1
1.2 Surveying .................................................................................................................2
1.2.1 Primary Division of Survey ..........................................................................3
1.2.2 Classification of survey.................................................................................3
1.2.3 Principle of Surveying ..................................................................................4
1.3 Accuracy and Errors ................................................................................................5
1.4 Sources of errors ......................................................................................................5
1.5 Kind of error ............................................................................................................5
1.6 Permissible error......................................................................................................5
1.7 Objectives of Survey Camp .....................................................................................6
1.8 Project Area .............................................................................................................6
1.8.1 Location and Accessibility............................................................................7
1.8.2 Topography and Geology .............................................................................8
1.8.3 Climate, Rainfall and Vegetation..................................................................8
1.8.4 Description of Work .....................................................................................8
1.9 Technical Terms.....................................................................................................10
CHAPTER 2 ................................................................................................................12
TOPOGRAPHICAL SURVEY ...................................................................................12
2.1 Objectives ..............................................................................................................12
2.2 Brief Description of the area..................................................................................12

vii
2.3 Norms (Technical Specification) ...........................................................................12
2.4 Equipment and Accessories...................................................................................14
2.5 Methodology..........................................................................................................14
2.5.1 Reconnaissance..........................................................................................14
2.5.2 Traversing ..................................................................................................16
2.5.3 Major Traverse...........................................................................................16
2.5.4 Minor Traverse...........................................................................................18
2.5.5 Coordinate Computation............................................................................19
2.5.6 Detailing.....................................................................................................20
2.5.7 Levelling ....................................................................................................21
2.5.8 Computation and Plotting ..........................................................................27
2.5.8.1 Computation and Plotting of Major Traverse..............................27
2.5.8.2 Computation and Plotting of Minor Traverse.............................30
2.5.9 Contouring .................................................................................................31
2.5.10 Output ......................................................................................................32
2.5.11 Comments and Conclusion:.....................................................................32
CHAPTER – 3 .............................................................................................................34
BRIDGE SITE SURVEY ............................................................................................34
3.1 Introduction............................................................................................................34
3.2 Objectives ..............................................................................................................34
3.3 Brief Description of the area..................................................................................35
3.4 Hydrology, Geology and Soil Condition ...............................................................35
3.5 Technical Specification (Norms) ...........................................................................35
3.7 Methodology..........................................................................................................36
3.7.1 Reconnaissance..........................................................................................37
3.7.2 Site Selection .............................................................................................37
3.7.3 Fixing of control points and triangulation .................................................38
3.7.4 Topographic survey ...................................................................................38
3.7.5 Levelling ....................................................................................................39
3.7.6 Longitudinal Section................................................................................41
3.7.7 Cross-Section.............................................................................................41

viii
3.7.8 Detailing.....................................................................................................42
3.7.9 Computation and Plotting ..........................................................................42
CHAPTER- 4...............................................................................................................45
ROAD ALIGNMENT SURVEY ................................................................................45
4.1 Introduction...........................................................................................................45
4.2 Objectives ..............................................................................................................46
4.3 Brief Description of the Area................................................................................46
4.4 Hydrology, Geology and Soil condition...............................................................46
4.5 Technical Specification (Norms) ...........................................................................47
4.7 Design Parameters .................................................................................................48
4.8 Methodology..........................................................................................................48
4.8.1 Reconnaissance...........................................................................................48
4.8.2 Selection of Intersection Point (IP)............................................................49
4.8.3 Fixing of Intersection Point (IP) ................................................................49
4.8.4 Topographic Survey....................................................................................49
4.8.5 Horizontal Alignment .................................................................................49
4.8.6 Curve Setting .............................................................................................50
4.8.7 Vertical Alignment.....................................................................................56
4.8.9 Longitudinal Section.................................................................................56
4.8.10 Cross-Section...........................................................................................56
4.8.11 Computation and Plotting........................................................................56
4.8.12 Comments and Conclusion ......................................................................57
ANNEX – A.................................................................................................................58
DATA AND CALCULATON OF TOPOGRAPHIC SURVEY ................................58
A.1 Two Peg Test Observation and Calculation Sheet ………………………….…..59
A.2 Fly Levelling Observation and Calculation Sheet (TBM to CP2)……….….…..60
A.3 Two Way Distance Measurement (Major Traverse)……………………….……63
A.4 Horizontal Angle Observation Sheet (Major Traverse)…………………………64
A.5 Gale's Table (Major Traverse)…………………………………………….……..65
A.6 Fly Levelling: Observation and Calculation Sheet (Major Traverse)………….. 66
A.7 Two Way Distance Measurement (Minor Traverse)………………………….…67

ix
A.8 Horizontal Angle Observation Sheet (Minor Traverse)…………………..……..68
A.9 Gale's Table (Minor Traverse)……………………………………………..……69
A.10 Loop Levelling Observation and Calculation Sheet (Minor Traverse)…..….....70
A.11 Detailing Sheet with Independent Co-ordinates………………………… ….…73
ANNEX – B……………………………………………………………………… …89
DATA AND CALCULATON OF BRIDGE SITE SURVEY………………….……89
B.1 Two Way Distance Measurement (Bridge)……………………………………...90
B.2 Horizontal Angle Observation Sheet (Bridge)………………………………… .91
B.3 Gale's Table of Bridge………………………………………………………… ..92
B.4 Fly Levelling Observation and Calculation Sheet (Bridge)……………………..93
B.5 Loop Levelling Observation and Calculation Sheet (Bridge)…………………...95
B.6 Reciprocal Levelling (Bridge)…………………………………………………...96
B.7 Detailing Sheet with Independent Co-ordinates……………………...……… …97
ANNEX – C……………………………………………………………………..….109
DATA AND CALCULATON OF ROAD SITE SURVEY……………………..…109
C.1 Chainage Computation of Curve in Road Alignment...……………………..… 110
C.2 Bearing Calculation of Road Alignment……………………………………….111
C.3 Fly Levelling Observation and Calculation Sheet (TBM to IP0)………..……..112
C.4 Profile Levelling and Cross Sectioning Sheet……………………...………..…113
ANNEX – D……………………………………………………………………...…124
DRAWING IN TOPOGRAPHIC SURVEY……………...……………………..…124
D.1 Major and Minor Traverse Plotting………………………………………… …125
D.2 Topographic Map……………………………………………………………....126
ANNEX – E………………………………………………………………………....127
DRAWING IN BRIDGE SITE SURVEY……………...………………………..…127
E.1 Topographic Map (Bridge)…………………………………………………..…128
E.2 Longitudinal Section of River……………………………………………….....129
E.3 Cross Section of River……………………………………………………….....130

x
ANNEX – F…………………………………………………………………………136
DRAWING IN ROAD SITE SURVEY……………...…………………………..…136
F.1 Road Alignment………………………………………………………………...137
F.2 Profile Levelling of Road Site Survey………………………………………….138
F.3 Cross Section Levelling of Road Site Survey……………………………..……139
CONCLUSION..........................................................................................................210
BIBLIOGRAPHY......................................................................................................211

xi
LIST OF FIGURES
Figure 1: Location Map of Survey Camp Site…………………………………………..…7
Figure 2: X & Y Coordinate Calculation………………………………………………….20
Figure 3: Z Coordinate Calculation……………………………………………………….20
Figure 4: Two peg test when the instrument is placed in between A & B………….…23
Figure 5: Two peg test when the instrument is placed behind A………….……..….…24
Figure 6: Reciprocal Levelling…..………………………………………………..……….40
Figure 7: Deflection Angle…..………………………………………………..…..….…….50
Figure 8: Elements of Simple Circular Curve..………………………………………….52

1
CHAPTER 1
INTRODUCTION
1.1 Background
Surveying, the first step of starting a new civil engineering project, is a very important
branch of civil engineering. To understand the techniques of surveying a student must
carefully study the basics of it. Surveying includes the technique of establishing
points by predetermined angular and linear measurements. A map represents the
horizontal projection of the area surveyed and not the actual area. But the vertical
distance can be represented more correctly by drawing sections.
The B.E. Survey Camp 2080, Bungmati, Lalitpur organized by the Department of
Civil Engineering Survey Instruction Committee, Aryan Engineering College for the
partial fulfillment of the requirement for the Bachelor’s Degree in Civil Engineering
as per the syllabus of Purbanchal University in the third year first part carrying a total
of 100 marks. The total duration of the survey camp was 12 days, from 13th of Kartik
to 24th
of Kartik, 2080.
This is a detailed report of the works performed by group no. 4 during the camp
period. It briefly explains the working procedures and technique along with the
observations, calculations, and methods of adjustment of error. In addition, it also
contains the main problem faced during work and their solution, results of all
calculations.
The first task dealt during the project is road alignment survey. It is mainly focused on
the fixing the alignment of the road depending on field condition. The curve
designing, L-section along the proposed road alignment, Cross-section at every 15m
interval and other geological and topographical information of the site are also
presented on this report.
The second task dealt during the camp is Bridge Site Survey. It is mainly oriented on
preliminary knowledge on selection and planning of the site for the future
construction of bridge. This survey focused on collecting the preliminarily data such
as normal water flow, high water level , geological features of the ground for planning
and designing of the bridge. The L-section along the river, few cross-sections of
upstream and downstream of the bridge axis and topographical map of the site and the
control survey i.e. Triangulation survey is presented here.
The third task mainly dealt during the camping is topographic survey. The major
traverse is run to cover the entire area of the, Bode. As the area is very large, the
overall area is divided into different parts for detailing of minor traverse. Then each
area is surveyed by the different groups. So to cover all the details of own area, minor
traverses are established in suitable direction and position which can control all the
area. The no of station in minor traverse is kept more then two. So, we have

2
established two minor traverse station for detailing. Then the topographic map of own
area is prepared and presented here. The level is first transferred from PBM to the
TBM using fly levelling considering three loops. Then after TBM to the all major and
minor traverse stations. All the calculation and plotting of the above mentioned task
are presented in systematic way in this report.
Broadly speaking, this camp contains all type of problem of real Engineering work,
which we have to face in the future. From above mentioned points, we can conclude
that this Survey Camp makes us capable to face the problem on future and make
independent to complete any type of survey works.
The work done during the camp duration can be categorized into:
 Topographical survey
 Road alignment survey
 Bridge site survey
1.2 Surveying
Surveying is the art of determining the relative positions of distinctive featuresof
surface of the earth or beneath the surface of the earth, by the means of measurement
of distances, directions and elevations. The main objective of surveying is to prepare
plans and maps of areas. Thus, the subject emerges out to be the most important
before and during all engineering works like civil engineering works such as
designing and construction of highways, water supply systems, irrigation projects,
buildings etc.
The knowledge of surveying is advantageous to many phase of engineering as it
requires skills as well as knowledge of physics, mathematics and astronomy.
Surveying is the most essential work before and during the construction of civil
engineering projects like dam, bridge, highways, railways, buildings, irrigation
project, water supply system and many more. Most of the measurements of length in
surveying is taken as horizontal it’s because the main objective of surveying is to
prepare the plan or map this means the horizontal projection of the land.
Surveying is the initial sets of work that is done before the execution of any
civil engineering projects. Surveying is not a new science rather it is the science
that has been developing since the initial stage of human civilization according
to their requirements. The map preparation that is done after surveying is not a
new thing but the instrument that was used in ancient times is not same to the
instruments that are used today. The surveying that used to take a long time can
now be completed in a fraction of that time. In the absence of the map, it is nearly
impossible to layout the alignments of road, canals tunnels, transmission power line,
and microwave or television relaying towers and so on in an effective manner. Hence
the surveying is an important aspect of a project and is a most.

3
1.2.1 Primary Division of Survey
As to whether the surveyor must retard the earth surface as curved or may regard it is
a plane depends upon the character and magnitude of the survey, and upon the
precision required. Primarily, surveying can be divided into plane and geodetic.
In plane surveying, mean surface of the earth is considered as a plane and spheroidal
shape is neglected, all triangle formed are considered as plane triangles, level line is
consider as straight and plumb line are considered parallel. It is reasonable for the
area involving less than 250 sq. km. since length of an arc 12 km long lying on the
earth surface is only 1 cm greater then the subs tended chord. And the difference
between the sum of angles in a plane triangle and sum of those in spherical triangle is
only 1 second for a triangle at the earth surface having area of 195 sq. km.
In geodetic surveying, the shape of the earth is taken into account. All line are curved
line, all triangle are spherical triangle so, it involves spherical trigonometry. The
object of geodetic survey is to determine the precise position on the surface of the
earth, of a system of widely distant point which forms the control station to which
survey of less precision may be referred.
1.2.2 Classification of survey
Survey may be classified on the different heading depending upon the uses or purpose
of resulting map.
 Based on Nature of Field Survey:
 Land Survey: It includes topographical, cadastral and city survey.
 Hydrographic survey
 Astronomical survey
 Based on object of survey:
 Engineering survey
 Military survey
 Mine survey
 Geological survey
 Archaeological survey
 Based on Instrument used:
 Chain survey
 Theodolite survey
 Traverse survey
 Triangulation survey
 Tachometric survey
 Plane table survey
 Photogrammetric survey
 Aerial survey

4
In our survey camp, the type of survey that we performed is engineering survey
which includes the preparation of topographic map, in which both horizontal
and vertical controls are necessary. As per instrument used we perform
theodolite traverse survey for fixing control points, tachometric survey for
detailing and triangulation survey for establishing control points in bridge site
survey.
1.2.3 Principle of Surveying
The fundamental principle of surveying are:-
 Working from whole to part:
It is very essential to establish a first system of control points with higher
precision. Minor control points can then be established by less precision
method and details can be located using minor control points by running minor
traverse. This principle is applied to prevent the accumulation of error and to
control and localize minor error.
 Location of point by measurement from two points of reference:
The relative position of points to be surveyed should be located by
measurement from at least two point of reference, the position of which have
already been fixed.
 Consistency of work:
The survey work should performed by keeping consistency in method,
instrument, observer etc, to get desired level of accuracy.
 Independent check:
Every measurement taken in the field must be checked by some independent
field observation so that the mistake is not passed unnoticed.
 Accuracy required:
Proper method and proper instrument should be used depending upon amount
of accuracy required. Accuracy of angular and linear values should be
compatible.
Thus, in our survey camp, survey work is performed by considering the above
fundamental principal of surveying.

5
1.3 Accuracy and Errors
1.3.1 General
Precision is the degree of perfection used in the instrument, the methods and the
observations. Accuracy is the degree of perfection obtained which depend on precise
instrument to simplify the work, save time and provide economy, on precise method
to reduce the effect of all type of error, and good planning to save time and reduce the
possibility of errors. The important function of surveyor is to secure measurements
which are correct within a certain limit of error prescribed by nature and purpose of
particular survey. A discrepancy is the difference between two measured values of the
same quantity, it is not an error.
1.4 Sources of errors
Error may arise from these sources:
 Instrumental error: Error arising due to imperfection or faulty adjustment of
the instrument with which measurement is being taken. E.g. a tape too short.
 Personal error: Error arising due to want of perfection of human sight in
observing and of touch in manipulating instrument. E.g. error in taking level
reading.
 Natural error: Error due to variation in natural phenomenon such as
temperature, refraction, magnetic declination etc.
1.5 Kind of error
Error may be classified as:
 Mistake: Error arising from inattention, inexperience, carelessness and
confusion in the mind of observer. If undetected, it produces a serious effect.
Hence, every measurement to be recorded in the field must be checked by
independent check.
 Systematic error: Error that under the same condition will always be of same
size and sign, a correction can be determined and applied, these make the
result too great or too small accordingly treated as positive or negative error.
 Accidental error: Are those which remain after mistake and systematic error
have been eliminated and caused by a combination of reason beyond the
ability of observer to control. They tend sometimes in one direction an
sometimes in other. Accidental error represented the limit of precision in the
determination of value.
1.6 Permissible error
It is the maximum allowable limit that a measurement may vary from the true value or
from a value previously adopted is correct. Its magnitude in any given case depends
upon the scale, purpose of the survey, the instrument available, class of the work etc.
the limit of error cannot be given once for all. The best surveyor is not he, who is
extremely accurate in all his work, but he who does it just accurately enough for the
purpose without waste of time and money.

6
1.7 Objectives of Survey Camp
From the early civilization of men, surveying has been developing since then. The art
of surveying and the preparation of maps have been practiced from the ancient times.
In absence of the accurate maps, it is impossible to layout the alignment of roads,
canals, bridges, tunnels, transmission power lines and waves relaying towers
accurately. Surveying is the preliminary step for the execution of such projects.
The main objective of the survey camp is to provide a basic knowledge of practical
implementation of different surveying works. It helps to build up the self-confidence
level by implementing different surveying works.
The main objectives of survey camp can be listed as follows:
 To become familiar with the surveying problems that are arise during the field
works.
 To give the opportunity to use the theoretical knowledge on Civil engineering
survey on the real field condition.
 To become familiar with the different surveying instruments, their parts, their
functions and their handling procedure for efficient surveying.
 To conduct the topographical survey of given area with horizontal and vertical
control and accomplishing the relevant specification and produce a
topographic map.
 To transfer the level or vertical control from known point (PBM) to TBM near
the site and to find level of different control points.
 To align the road interconnecting the points and find the longitudinal and cross
sections.
 To study the details of bridge site and align a bridge axis.
 To compute and manipulate the observed data in the required accuracy and
present it in diagrammatic and tabular form in order to understand by other
engineers and related personnel easily.
 To tackle the mistake and incomplete data from the field while in office work.
 To know the complete method of report preparation.
 To become familiar with the teamwork as the surveying is not a single person
work.
1.8 Project Area
Our project area is Mars Nepal Engineering Survey Camp Pvt. Ltd. and it took
about one and half hour by bus to reach the destination from our college. The area
allocated to us is about 76320.56 square meter located at 9 km south east of Pulchwok
Engineering Campus, and 6 km far from Ekantakuna Chakrapath Chowk at Lalitpur
followed by Nakhu, Bhaisipati and Bungmati. The area to be surveyed contains
variable land features and man made features like pond, buildings, sports ground,
cannels and roads.

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1.8.1 Location and Accessibility
The survey camp was situated in central region of Bagmati zone, province no. 3
which is located in lalitpur district and conducted at Bungmati, Karyabinayak- 12,
inside the premises of MARS Nepal Engineering Survey Camp Pvt. Ltd. The place
is geographically located between 85° 17’ 39” and 85° 18’ 46” longitude and 27° 36’
48” and 27° 36’ 57” Latitude (Figure 1). The altitude of the place is around 1277m. It
is about 8 hectares of semi built-up landform situated on the northern bank of the
Bagmati River. Between Bagmati river and the site passes the mega highway project
of Nepal called “Kathmandu/Madesh Expressway”.
The location is easily accessible through the roadway. Through ring road of
Kathmandu Valley, one has to reach Ekantakuna. Turning left and taking Ekantakuna-
Tikabhairab Road, it is a 4.0 km straight ride onto Bungmati Road which will lead us
to MARS Engineering Survey Camp Pvt. Ltd.
Figure 1 : Location Map of Survey Camp Site

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1.8.2 Topography and Geology
Mars Nepal Engineering Survey Camp is a semi built up landform. The terrain has a
gentle downward slope from North towards south. An express highway passes along
the western and southern boundary of the area. There are plenty and permanent
features like buildings, cottages, etc. Rivers flow at southern side of area. There are
thinly scattered trees and forest inside the premises. Some chunks of the land are used
for cultivation and cattle habitat. A part of the area on the western side near the
bamboo forest has a steep slope. However, a significant portion of the area is nearly
flat and terraced.
Talking about geological feature of the area, the campsite area is geologically sound.
Rocks or their exposure can be barely seen around the area. The area has gentle relief
and steep slope and held tight by trees, so that no mass movements can be expected in
the premise.
1.8.3 Climate, Rainfall and Vegetation
The climate of the campsite area is mild, and generally warm and temperate. The
average annual temperature around the area is 14.1°C. The temperature during the
summer season ranges from 16°C to 28°C and 2°C to 17°C during winter season.
In a year, most rainfall occurs during the summer season. Generally, 90mm of
precipitation occurs during summer. There are very few records of rainfall during the
winter season.
The area contains full of vegetation and agricultural land lying in deciduous monsoon
forest zone. Ordinary grassland covers some area. It includes Oak, Maple, Bamboo,
Elm, etc. and crops like maize, wheat, millet, paddy are grown. Presence of plants,
trees, and bushes made environment green and pleasant.
The temperature during the camp period varied from 20
C to 170
C. In morning, the
area is surrounded by fog, it was so difficult to do work in morning time with
instruments. The days were colder in morning time whereas in the evening, wind blew
throughout the camp period making the evening pleasant.
1.8.4 Description of Work
1.8.4.1 Traversing
 Number of Major Traverse Stations: 16 (Including CP1 & CP2)
 Number of Minor Traverse Stations: 2
 Length of perimeter: 743.983m
 Longest leg length: 65.307m
 Shortest leg length: 34.553m
 Scale of Topographic Map: 1:500
 Contour interval: 0.5m

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1.8.4.2 Levelling
1. For Topographic Survey
 RL transfer from PBM to TBM using Fly levelling considering three loops
i.e. (PBM to SBM1, SBM1 to SBM2, SBM2 to TBM) whereas the RL of
PBM is 1258.000m
 RL transfer From TBM to CP1 using Fly levelling and loop levelling from
CP1 to CP2 including minor traverse station.
2. For Bridge Site Survey
 RL transfer from SBM (RL=1350.000m) to main triangulation station A by
fly levelling.
 Loop levelling is used to transfer RL on triangulation station of same bank.
 Reciprocal Levelling is used to transfer the RL from one bank to another
bank.
3. For Road Alignment survey
 RL transfer from TBM to TP1 using Fly levelling.
1.8.4.3 Bridge Site Survey
 Bridge Span: 49.474m
 No. of Triangle Formed: 2
 Cross Section: Upto 150m on upstream and 50m on downstream
 Scale of Topographic Map: 1:500
 Contour interval: 0.5m
 Longitudinal Section Scale: Horizontal: 1:500 & Vertical: 1:50
 Cross Section Scale: Horizontal: 1:50 & Vertical: 1:50
1.8.4.4 Road Alignment Survey
 Starting point of the road: IP1
 Road type: Mars Survey Camp ground surface
 Length of Road: 679.570m
 Number of intersections points:
 Cross Section: 10m left and 10m right on both sides of the center line
 Longitudinal Section: In 15m interval
 Longitudinal Section Scale: Horizontal: 1:1000 & Vertical: 1:100
 Cross Section Scale: Horizontal: 1:100 & Vertical: 1:000

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1.9 Technical Terms
1. Reduced Level (RL)
RL is the elevation of survey point with reference to commonly assumed
datum (Mean Sea Level or MSL).
1. Bench Mark (BM)
A survey mark established at a known elevation (RL) used for the reference
point for RL of any other point. It can be
a) Site bench mark (SBM) – BM established on site having known RL
b) Temporary bench mark (TBM) – temporarily established BM
2. Levelling
Levelling is a process to determine the vertical position of different points
above, on, or below the ground. Few types of levelling that has to be done are
as follows:
a) Fly levelling: It is the levelling that is to connect benchmark to the
starting point of the survey line. It is very approximate form of
levelling in which only back sight and fore sight readings are taken.
b) Loop levelling: Loop levelling is one in which levelling starts from a
benchmark up to the required point then closing back to the same
benchmark.
c) Reciprocal levelling: Levelling between two widely separated points
in which observations are made in both directions to eliminate the
effect of atmospheric refraction and curvature of earth.
3. Profile Levelling
Profile levelling is the process of levelling along the fixed line to determine
the elevations of the ground surface along the line. It is also known as
longitudinal sectioning.
4. Cross section levelling
Levelling done to determine the elevation of the points on perpendicular
direction of succession lengthwise line of highway is called cross section
levelling.
5. Back Sight(BS) reading
It is the first staff reading at the point of known elevation.
6. Fore Sight(FS) reading
It is the staff reading at a point where the RL is to be calculated and after that
reading the instrument station is going to be changed.

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7. Intermediate sight ( IS) reading
It is the staff reading at a point where the RL is to be calculated and after that
reading the instrument station is not going to be changed.
8. Contour line
The imaginary line on the ground joining the point of point of equal elevation
is called contour line.
9. Traversing
A traverse is a series of connected straight lines each joining two ground
station on the ground whose length and directions are to be measured and the
process surveying to find such measurements is called is known as traversing.
10. Topographic Map
The map used to describe the shape of land is called topographic map. They
describe the natural and manmade features of the land.
11. Curve
Curves are the regular bends provided in the line of communication like roads,
railways etc. to bring about gradual change of direction.
12. Triangulation:
Triangulation is the process of determining the location point by measuring
only angles to it from known points at either end of a fixed baseline by using
trigonometry, rather than measuring distances to a point directly as in
trilateration.
13. Mean Sea Level (MSL)
Mean sea level is the average height of the sea at tide station measured from a
fixed or determined reference level, it is a datum to which elevations and
contour intervals are generally referred.

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CHAPTER 2
TOPOGRAPHICAL SURVEY
Topographical Surveying is the process of determining the positions of natural and
artificial features of the locality by means of conventional signs up on a topographical
map. Topographic surveys are three-dimensional; they provide the techniques of
plane surveying and other special techniques to establish both horizontal and vertical
control. The topographic maps are very essential for the planning and designing
of the most of the engineering projects such as highways, design of irrigation and
drainage systems, developments of water power, layout of the industrial plants and
city plannings. Topographic is simply the graphical representation of the earth’s
surface.
Hence the fieldwork in a topographical surveying consists of three parts.
 It establishes both horizontal and vertical control.
 It locates the contours.
 It locates the details such as rivers, streams, lakes, roads, houses and trees etc.
2.1 Objectives
The main Objective is to prepare the topographic map of the given area with
horizontal control and vertical control with required accuracy. This also includes
the calculation and diagrammatic Representation of the area with the help of
coordinates in the paper with gridlines.
2.2 Brief Description of the area
The topographical survey was performed inside the premises of Mars Nepal
Engineering Survey Camp Pvt. Ltd. The area is about 150 ropani and contain gentle to
steep slope with some flat area too. The area to be surveyed contains variable land
features and manmade features like ponds, buildings, sport grounds, cannels and
roads. The area through which the major traverse was run was surrounding area of
Mars Nepal survey camp. Along with the preparation of the topographical map of the
major traverse, detailed topographical map of the small area with contours was also
prepared.
2.3 Norms (Technical Specification)
 Conduct reconnaissance survey of the given area. Form a close traverse
(major and minor) around the perimeter of the area by making traverse station.
In the selection of the traverse station the ratio of maximum traverse leg to
minimum traverse leg should be equal to or less than 1:2 for major traverse

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and 1:3 for minor traverse.
 Measure the traverse legs in the forward and reverse directions by means of a
total station provided in the field, note that discrepancy between forward and
backward measurement should be lesser than 1:5000 for major traverse and
1:3000 for minor traverse.
 Traverse angles were observed on two set for major traverse and one set for
minor traverse. The difference between two set reading within 20 second also
notice that difference between face left and face right is within 1800
±20
seconds.
 Perform two-peg test before the start of leveling. Note that collimation error
should be less than 1:10000. Maintain equal fore sight and back sight distances
to eliminatecollimation error. Permissible error for ordinary leveling is ±25√k
mm, where k is the distance in kilometer. Given RL of PBM = 1258.00m
 Balance the traverse. The permissible angular error for the sum of interior
angles of the traverse should be less than ±30"√N and ±1'√N for major and
minor traverse respectively. The sum of interior/exterior angles in a closed
traverse was found to be equal to (2N ± 4) ∗ 900
where, N is total number of
stations. For major and minor traverse, the relative closing error found to be
less than 1:5000 and 1:3000 respectively.
 Distribute the error to all traverse leg and finally find the corrected angle.
 Calculate bearing of all line using following formula
Bearing of next line (θ) = Previous line bearing + HA ± 1800 − 5400
 Calculate Latitude and Departure as, Lat = Lcos(θ)and Dep = Lsin(θ)
 Find Total sum of Latitude and Departure
 For Closed loop, the total sum of Latitude and Departure must be zero. Then,
calculate theclosing error as Closing error =√∑Lat2 + ∑Dep2 and accuracy =
1/(Length/Error)
 Distribute the error using Bowditch or Transit rule. Bowditch rule distribute
the error to each traverse according to their respective length. Bowditch
method is used when both linear and angular distribution are of equal
precision. We use Bowditch rule for distributingthe error.
 Plot the major and minor traverse stations by coordinate method in
appropriate scale (1:1000 for major traverse and 1:500 for minor traverse) in
grid sheet.
 Carry out the detail survey of the given sub area by total station and
tachometric surveyingwith reference to the major and minor traverse, which
have been already plotted. Use conventional symbols for plotting.

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2.4 Equipment and Accessories
 Total Station or Theodolite
 Leveling staffs (5m) and Ranging Rods
 Measuring Tapes (30m & 50m)
 Leveling instrument
 Hammer
 Arrow & pegs
 Tripod
 Poles
 Compass
 Prism
 Prism Clamp
 Marker
 Reflector
 Field Book, Drawing Paper, Grid sheet etc.
2.5 Methodology
The methodology of surveying is based on the principle of surveying. They are as
follows:
 Working from whole to a part.
 Independent check.
 Consistency of work.
 Accuracy required
The different methodologies were used in surveying to solve the problems arise in the
field are as follows:
2.5.1 Reconnaissance
Recci means the exploration or scouting of an area. In survey, it involves walking
around the survey area and roughly planning the number of stations and the position
of the traverse stations. Recci is primarily done to get an overall ideaof the site.
This helps to make the necessary observations regarding the total area, type of
land, topography, vegetation, climate, geology and intervisibility conditions that help
in detailed planning. The following points have to be taken into consideration for
fixing traverse stations:
 The adjacent stations should be clearly intervisible.
 The whole area should include the least number of stations possible.
 The steep slopes and badly broken ground should be avoided as far as
possible, which may cause inaccuracy in taping.
 The traverse line of sight should not be near the ground level to avoid the
refraction
 Thinking the above given points into consideration, the traverse
stations were fixed. Then two-way taping was done for each traverse leg.

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2.5.1.1 Field Procedure
 Reconnaissance survey of the provided area was performed, and then closed
major traverse was established, consisting minor traverse framework within or
outside the major framework.
 Inspection of whole area was done by walking all over the site and preparation
of Index Sketch (Showing number and position of Major Traverse station (M.T),
minor Traverse station (m.t), important natural and human made field details
within and around traverse area and direction of working) in A2 size paper.
 When selecting these stations, ensured that they have direct line of sight to one
another and obstacles between them was avoided as far as possible.
2.5.1.2 Technical Specification
After recci, fixing of station ensured in such a way that;
For major traverse:
 Traverse was made to run in anticlockwise direction, and work was performed
in that direction.
 Leg ratio was maintained within 2:1. Leg ratio means the ratio of the length of
the longest leg to that of the shortest leg. Leg ratio higher than 2:1 is
considered inappropriate as it leads to disproportionate balancing during the
Bowditch Method of correction to closing error.
 We did not let the traverse leg form an angle less than 30° and within
180°±20".
 Stations was properly spaced such that the whole area can be surveyed with
the least number of stations.
 A more or less leveled surface were sought, avoiding steep slopes and badly
broken grounds, to ensure the setting up of the tripod will be safe and easy.
 The Traverse line of sight should not pass near the ground level to avoid
refraction, we maintained.
For minor traverse:
 Leg ratio up to 3:1 was allowed. It was maintained within 3:1
 Stations were maintained in such a way that they located at the commanding
location from where a large area can be controlled at a single instrument
setup.

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2.5.2 Traversing
Traversing is a type of surveying in which a number of connected survey lines form
the framework. It is also a method of control surveying. The survey consists of the
measurement of
 Angle between successive lines or bearing of each line
 The length of each line
There are two types of traverse. They are as follows:
(i) Close Traverse:
The traverse in which final station co-incide with initial station is called
closed traverse. In other words the traverse in which traverse line runs in
between known co-ordinates is also known as close traverse. Linked
traverse is one of the example of closed traverse.
(ii) Open Traverse:
The traverse in which final station does not coincide with initial station is
called open traverse.
2.5.3 Major Traverse
The skeleton of lines joining those control points, which covers the whole entire area,
is called Major Traverse. It is a controlling framework in which the angle and distance
measurements are done in a highly precise manner. It should run in anticlockwise
direction.
 An overall sketch was prepared in A2 size paper forming a closed major
traverse stations.

17
 Referencing of each traverse station was taken and shown in sketch which had
done by taking measurements from three permanent points making Y-shape
and orienting the sketch approximately towards the north direction.
 Station pegs were marked as 4M1 for major traverse.
 Prefix number 4 was our survey camp group number.
 Letter M denoted the Major traverse station.
 Suffix number 1denoted the traverse station number.
 We used the same notation in plotting except for common station (used CP1
and CP2 for common station).
 16 major control stations were formed which included 4M1, 4M2, .......4M14
and two reference control points CP1 and CP2.
 A leg ratio of 1:1.89 was obtained. Distance of each leg was measured in both
forward and backward direction with precision ratio within 1:5000 using
EDM.
 Two sets (0° set and 90° set) of horizontal angle observation were done. In
each set, face left and face right observations were taken.
 The sum of interior angle was observed 25190
58' 30" with error 1' 30" which
is within permissible limit.
 Precision of total length was obtained with precision 1:9173.
Horizontal Control (Angular Measurement)
 Two sets of horizontal circle reading of major traverse stations were taken by
Total Station. The difference between face left and face right reading was
maintained within 1800
± 20" and the difference between the mean angles of
two sets reading was observed within a minute.
 The traverse was balanced by proper way adjusting angular and linear closing
errors. The theoretical sum of interior/exterior angles in a closed traverse
should be equal to (2N-4) ∗ 900
. The permissible angular error for the sum of
interior angles of the traverse should be less than 30"√N for major traverse, it
was accurately observed within permissible limit.

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Horizontal control (Linear Measurement)
 Two-way traverse leg distance was measured (i.e. in the forward and backward
directions) by total station.
 The precision for major traverse on forward and backward distance
measurements by Total Station should be ≥1:5000, which was precisely
observed by taking observation of minimum four times.
 Relative precision or total error of closure should be less than 1:5000 for major
traverse which was precisely observed as 1:9173.
2.5.4 Minor Traverse
For the detailed topographical survey, the detail points may not be sufficiently
obtained from the control stations of the major traverse. For this minor traverse need
to be laid. Minor traverse is that one which runs through the area to make detailing
easy. Minor Traverse covers only small area. Less precise work than that of major
traverse is acceptable so that single set reading is sufficient. The minor traverse had 6
control stations. The stations were named as 4m1 & 4m2. The leg ratio of maximum
traverse leg to minimum traverse leg was maintained within 3:1. The precision in
length between the forward measurements and the backward measurements of all the
traverse legs was within 1:3000.
 An overall sketch was prepared in A2 size paper forming a closed minor
traverse stations.
 Referencing of each traverse station was taken and shown in sketch which had
done by taking measurements from three permanent points making Y-shape
and orienting the sketch approximately towards the north direction.
 Station pegs were marked as 4m1 for major traverse.
 Prefix number 4 was our survey camp group number.
 Letter m denoted the minor traverse station.
 Suffix number 1 denoted the traverse station number.
 Two minor stations were fixed between CP2 and 4M13, named 4m1 & 4m2.
 A leg ratio of 1:1.89 was obtained. Distance of each leg was measured in both
forward and backward direction with precision ratio within 1:3000 using
EDM.
 Single set of horizontal angle observation were taken. In this set of
observation, face left and face right observations were taken.

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 The sum of interior angle was observed 7190
59' 19".
 Total error of closure was observed as 1:3143
Horizontal Control (Angular Measurement)
 Single set of horizontal circle reading of major traverse stations were taken by
Total Station. The difference between face left and face right reading was
maintained within 1800
± 20"
 The interior angle required to be observed was (n+2), where n= no of minor
stations.
 The traverse was balanced by proper way adjusting angular and linear closing
errors. The theoretical sum of interior/exterior angles in a closed traverse
should be equal to (2N-4) ∗ 900
. The permissible angular error for the sum of
interior angles of the traverse should be less than 1'√N for minor traverse, it
was accurately observed within permissible limit.
 The bearings of legs were calculated and applied check in bearing of leg
4M13-4M14, the allowable error in bearing is ±1.5'√N
Horizontal Control (Linear Measurement)
 Two-way traverse leg distance was measured (i.e. in the forward and backward
directions) by total station.
 The horizontal distance required to be observed was (n+1), where n=no of
minor stations.
 The precision for minor traverse on forward and backward distance
measurements by Total Station should be ≥1:3000, which was precisely
observed by taking observation of minimum two times.
 Relative precision or total error of closure should be less than 1:3000 for minor
traverse which was precisely observed as 1: 3143.
2.5.5 Coordinate Computation
The length of the traverse is measured by total station. The traverse angles are
measured with a total station by setting up the instrument at each station. The bearing
of the CP1-CP2 traverse leg was given and the entire traverse angle measured, the
bearing of all the legs can be calculated by:
Bearing of next line (θ) = Previous line bearing + HA ± 1800 − 5400
If θ is the bearing of line BM-A and Lo be the length of the lineand provided that
co-ordinate of the Bench Mark (BM) is known,then the co-ordinate of the point ‘A’
can be calculated as follows:

20
X-Coordinate of A = X-Coordinate of BM + Departure (Losinθ)
Y-Coordinate of A = Y-Coordinate of BM + Latitude (Locosθ)
Then, Coordinate of B can be calculated as,
X-Coordinate of B = X-Coordinate of A + Departure (L1sinθAB)
Y-Coordinate of A = Y-Coordinate of A + Latitude (L1cosθAB)
Calculation of Z Co-ordinate
RL of B = RL of A + HI + VD – M
VD = K ∗ S ∗ Sin2θ
2
M – Middle hair reading
2.5.6 Detailing
Detailing means locating and plotting relief in a topographic map. Detailing can be
done by either plane table surveying or tachometric surveying. Plane tabling needs
less office work than tachometric survey. Nevertheless, during our camp, we used the
tachometric method.
2.5.6.1 Tachometry
Tachometry is a branch of angular surveying in which the horizontal and vertical
distances of points are obtained by optical means. Though it only has accuracy about
1/3000 to 1/5000, it is faster and convenient then the measurements by tape or chain.
It is very suitable for steep or broken ground, deep ravines, and stretches of water or
swamp where taping is impossible and unreliable.
The objective of tachometry survey is to prepare of contour maps or plans with both
horizontal and vertical controls. For the survey of high accuracy, it provides a check
on the distances measured by tape.
The formula for the horizontal distances is
H = 100*S* Cos2
θ
The formula for the vertical distances is
V = 100*S*( Sin2θ/2)
Where, S = staff intercept; θ = Vertical Angle
Figure 2: X & Y Coordinate Calculation
Figure 3: Z- Coordinate Calculation

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If the angle is used in zenithal angle than
H = 100*S* Cos2
θ
V = 100*S*( Sin2θ/2)
Where, θ = Zenithal Angle
2.5.7 Levelling
Levelling is an art of determining relative altitudes of points on the surface of the earth
or beneath the surface of the earth.
Levelling is the branch of surveying of the object which is:
(i) To find the elevation of given points with respect to given or assumed
datum.
(ii) To establish points at a given elevations or at different elevations with
respect to a given or assumed datum.
The first operation is required to enable the works to be designed while the second
operation is required in the setting out of all kinds of engineering works. Levelling
deals with measurements in a vertical plane.
To provide vertical controls in topographic map, the elevation of the relevant points
must be known so that complete topography of the area cab be explored.
Two types of levelling were performed at the site, namely direct levelling (spirit
levelling) and indirect levelling (trigonometric levelling)
1. Direct Levellng:
It is the branch of levelling in which the vertical distances with respect to a horizontal
line (perpendicular to the direction of gravity) may be used to determine the relative
difference in elevation between two adjacent points. A level provides horizontal line
of sight, i.e. a line tangential to a level surface at the point where the instrument
stands. The difference in elevation between two points is the vertical distance between
two level lines. With a level set up at any place, the difference in elevation between
any points within proper lengths of sight is given by the difference between the rod
reading taken on these points. By a succession of instrument stations and related
readings, the difference in elevation between widely separated points is thus obtained.
Following are some special methods of direct (spirit) levelling:
a. Differential levelling:
It is the method of direct levelling the object of which is solely to determine the
difference in elevation of two points regardless of the horizontal positions of the
points with respect of each other. This type of levelling is also known as fly
levelling.

22
b. Profile levelling:
It is the method of direct levelling the object of which is to determine the
elevations of points at measured intervals along a given line in order to obtain a
profile of the surface along that line.
c. Cross-sectioning:
Cross-sectioning or cross levelling is the process of taking levels on each side of
main line at right angles to that line, in order to determine a vertical cross-section
of the surface of the ground, or of underlying strata, or of both.
d. Reciprocal levelling:
It is the method of levelling in which the difference in elevation between two
points is accurately determined by two sets of reciprocal observations when it is
not possible to set up the level between the two points.
2. Indirect Levelling:
Indirect method or trigonometric levelling is the process of levelling in which the
elevations of points are computed from the vertical angles and horizontal distances in
the field, just as the length of any side in any triangle can be computed from proper
trigonometric relations.
2.1 Temporary adjustment of level:
The temporary adjustments for a level consist of the following:
a. Setting up the level:
The operation of setting up includes fixing the instrument on the stand and
leveling the instrument approximately.
b. Leveling up:
Accurate leveling is done with the help of foot screws and with reference to
the plate levels. The purpose of leveling is to make the vertical axis truly
vertical. It is done by adjusting the screws.
c. Removal of parallax:
Parallax is a condition when the image formed by the objective is not in the
lane of the cross hairs. Parallax is eliminated by focusing the eye-piece for
distinct vision of the cross hairs and by focusing the objective to bring the
image of the object in the plane of cross hairs.
2.2 Permanent adjustment of level:
To check for the permanent adjustment so level Two peg test is done;
Before starting fly levelling, two peg test was carried out to check the accuracy of the
level used.

23
 In a perfect level the line of collimation should be perpendicular to the
vertical axis and parallel to the axis of level tube.
 With constant use and mishandling of instrument, it may go out of perfect
adjustments.
 Two peg Test is conducted to check the perfectness of instrument (whether
the line of collimation is perpendicular to the vertical axis and parallel to axis
of the level tube or not).
 If the leveling instrument is not in perfect condition (the precision obtained is
less than 1 in 10,000) then permanent adjustment is required.
To conduct two peg test, two points were fixed on a level firm ground at distance of
about 30m & two set observations were taken.
 When instrument is placed in between A and B:
 Points A and B were selected on fairly level ground ad a distance 30m.
 The auto level was set (centered, leveled) at point C, exactly at midway
between the points A and B on the line AB.
 The levelling staff was held vertically (not allowed to tilt slightly) at points A
and B and the staff readings were taken.
Say, the staff reading at A is ‘a’ and the staff reading at B is ‘b’.
As the distances of the staff A & B from the level are equal, the errors due to inclined
sight, if any, will be equal. (error at A= error at B=error/ea=eb=e). So correct staff
reading at A is (a - ea) & correct staff reading at B is (b - eb).
Level difference between A & B is h, assuming B was higher than A;
h=correct staff reading at A - correct staff reading at B
h=(a-ea) - (b-eb) = a - e - b + e = a – b
True Level Difference between A and B is, h= a – b
 When instrument is placed behind A:
 The level was shifted behind A at a distance of La(=L/10) from A on the line
BA produced.
Figure 4: Two peg test when the instrument is placed in between A & B
Figure 4: Two peg test when the instrument is placed in between A & B

24
 After setting the level at D, the staff was vertically held at point A & B, and
the staff readings were taken.
Say, staff reading at A is equal to = a1 & staff reading at B is equal to = b1
Level difference between point A and B is h1.
h1=staff reading at A - Staff reading at B = a1 – b1
Apparent level difference between point A & B is, h1 =a1 – b1
2.5.7.1 Booking methods, their reduction & arithmetic checks:
There are two methods of booking and reducing the elevation of points from the
observed staff reading.
 Rise and fall method: In this method, the difference of level between two
consecutive points for each setting oh the instrument is obtained by comparing
their staff readings. The difference between their staff reading indicates a rise
if the back staff reading is more than the fore sight and fall if it is less than the
fore sight. The rise and fall is computed for all the points which gives the
vertical distance of each point relative to preceding one. If RL of back staff
point is known, the RL of the following point may be obtained by adding rise
or subtracting its fall from RL of preceding as the case may be.
Station BS IS FS Rise Fall Remarks
Total
Arithmetic Check:
The difference between the sum of back sights and the sum of fore sight
should be equal to the difference of sum of rises and the sum of falls and
should also be equal to difference between the RL of last point and RL of first
point i.e.
∑BS – ∑FS = ∑Rise – ∑Fall = Last R L – First R L
Figure 5: Two peg test when the instrument is placed behind A

25
 Height of collimation (Instrument) method: In this method, height of
instrument (HI) is calculated for each setting of the instrument by adding the
back sight (BS) reading to the elevation of the BM. The reduced level of the
first station is obtained by subtracting its fore sight from the instrument height
(HI). For the second setting of the instrument, the height of the instrument is
calculated by adding the back sight to the first station to its reduced level. The
reduced level of the last point is obtained by subtracting the fore sight of the
last point from the height of instrument at the last setting. If the intermediate
sight is observed to an intermediate station, its reduced level is obtained by
subtracting its foresight from the height of instrument for its setting.
RL of HI = RL of known point (BM) – (BS)
RL of ground = RL of HI –IS (or FS)
Arithmetic Check:
The difference between the sum of back sights and the sum of fore sight
should be equal to difference between the RL of last point and RL of first
point i.e,
∑BS – ∑FS = Last R L – First R L
2.5.7.2 Fly Levelling
The fly levelling was carried out between PBM and TBM, where two site bench mark
were fixed between them (i.e. SBM1 and SBM2) and check levelling were performed
to check the results. Also, the fly levelling was carried out from TBM to CP2 (second
common point) and check levelling was also performed.
2.5.7.2.1 Technical Specification
 To check the accuracy of leveling work, Permissible Closing Error=24√K
mm where K is loop distance in km.
 TBM was established at every 200 m distance to establish leveling loop for
each 200 m distance, it reduced the repetitions of leveling work when error
occurred more than the permissible value.
Station Distance BS IS FS HI RL Remarks
Total

26
 In this leveling balance sights was taken (B.S. distance - F.S. distance to
neutralize or minimize the effect collimation, refraction & curvature. The
permissible difference in BS distance & FS distance is 1 m)
 Three wires (Top, Middle & Bottom) readings were taken, to compute
horizontal distance between Instrument & staff and also to check the
observed reading. (Distance=100*(Top-Bottom reading) = 100*S &
= Middle reading, ±3 mm difference is permissible)
 The staff reading was kept in between 0.6 to 2 m to reduce the effect of
curvature, refraction & non-verticality of staff.
2.5.7.3 Loop Levelling
It is a differential leveling operated to transfer the RL from Site BM to the traverse
station. But the traverse station was so far from the traverse station so fly levelling
was carried out to calculate the elevation of traverse station CP1. Then, loop levelling
was started from CP1 for calculation of RL of minor traverse station and moved
towards the traverse station 4m1 & returns to the CP1 not going to another station and
it was corrected by further calculation. Then similar process was carried out to
calculate RL of next station 4m2.
Permissible error = ±24√k mm, where k is the total perimeter in Km
Actual Error (e) = ∑BS – ∑F.S. = Last R.L. – First R.L
Correction for RL of 4m1:
Corrected RL of 4m1= -e*L/p (here p=2L for looping within same line)
Corrected RL of 4m1= -e/2
Similarly, RL of another minor station was calculated and corrected and check
levelling was also performed at CP1 from 4M14.
Level transfer to the major and minor traverse stations:
The R.L of the temporary benchmark was then transferred to the control stations of
the major and minor traverse. The closing error was found to be within the
permissible limits. The misclosure was adjusted in each leg of the leveling path by
using the following formula:
Permissible error = ±24√k mm, where k is the total perimeter in Km
Actual Error (e) = ∑BS – ∑F.S. = Last R.L. – First R.L
Correction in ith
leg = -(e *
⋯
)
Where L1, L2……Li was length of 1st
, 2nd
…ith
leg, P is perimeter
Relative Precision = 1/(p/e)

27
2.5.8 Computation and Plotting
For the calculations as well as plotting, we applied the coordinate method (latitude
and departure method).
In this method, two terms latitude and departure are used for calculation. Latitude of a
survey linemay be defined as its coordinate lengths measured parallel to an assumed
meridian direction. Thelatitude (L) of a line is positive when measured towards north,
and termed Northing and it is negative when measured towards south, and termed
Southing. The departure (D) of a line is positive when measured towards east, and
termed Easting and it is negative when measured towards south, and termed Westing.
The latitude and departures of each control station can be calculated using the relation
Latitude = L Cosθ and Departure = L Sinθ
Where, L=distance of the traverse legs
θ = Whole Circle Bearing
If a closed traverse is plotted according to the field measurements, the end of the
traverse will not coincide exactly with the starting point. Such error is known as
closing error.
Mathematically,
Closing error =√∑Lat2 + ∑Dep2 and
Accuracy = 1/(Length/Error)
2.5.8.1 Computation and Plotting of Major Traverse
 Interior angles were observed, error was computed, correction can be applied
and finally corrected interior angles was computed.
 Observed sum of interior angle Addition of all observed angles
 Theoretical sum of interior angle = (n-2) ∗ 1800
 Error (e) = Sum of observed angle - Sum of theoretical angle
 If Error (e) < Permissible Error (p.e.), then calculate the correct angle by
subtracting or adding error equally to all the angles but avoid the fractional
distribution, by subtracting or adding more in large angle
 The observed interior angle was within precision and it was corrected by
applying correction.
 The bearing of one line CP1 and CP2 was observed by using compass.
 The bearing of remaining sides was calculated with the help of known bearing
and observed horizontal angle, where traverse progress is in anti-clockwise
direction.

28
2.5.8.1.1 Computation analysis
Bearing of any line = Bearing of preceding line + Included angle ± 180° or - 540°
Knowing the Length and bearing of traverse sides, Latitude (L) & Departure (D) of all
the sides were calculated.
Latitude (L) =L cos θ & Departure (D) = Lsin θ
The algebraic sum of all the Latitude & Departure should be zero if there was no error
but due to error in observations, the algebraic sum of all the Latitude & Departure
occurred as ∆𝐿 & ∆𝐷. Then, the magnitude & direction of closing was computed.
Magnitude of closing error = (∆𝐿)2 + (∆𝐷)2
Direction of closing error (θ) =tan
∆
∆
in Reduced Bearing (R.B.) system
Permissible closing error = 1 in 5000 (measurement was taken with Total station)
If error is less than permissible error, then coordinates is balanced by Bowditch’s
method or by Transit method.
 In our observation, the error was less than permissible error, then the
coordinates were balanced by Bowditch’s method.
Relative closing error:
The closing error is commonly expressed as a fraction having the numerator equal to
unity and this fraction is called relative closing error. It is computed with reference of
perimeter of the traverse.
Relative closing error = closing error / Perimeter of traverse = =
/
Balancing of traverse:
To balance the traverse, total error in Latitude & Departure was determined. Then
magnitude of closing error was determined. If closing error is less than permissible
error then errors an adjusted in such way that algebraic sum of all the latitudes and
departure should be equal to zero, means sum of northing should be equal to sum of
southing and sum of easting should be equal to sum of westing. The traverse can be
balanced by using one of the following methods:
1. Bowditch’s Method
2. Transit Method
1. Bowditch’s Method:
This method is used to balance the traverse when angular and linear
measurements are taken in equal precision during field observations. The error
in latitude and departure is distributed in proportion to the lengths of the sides. It
is most common method used in balancing the traverse.

29
Correction to Latitude of any side =
𝑻𝒐𝒕𝒂𝒍 𝒆𝒓𝒓𝒐𝒓 𝒊𝒏 𝑳𝒂𝒕𝒊𝒕𝒖𝒅𝒆 × 𝑳𝒆𝒏𝒈𝒕𝒉 𝒐𝒇 𝒕𝒉𝒂𝒕 𝒔𝒊𝒅𝒆
𝑷𝒆𝒓𝒊𝒎𝒆𝒕𝒆𝒓 𝒐𝒇 𝒕𝒉𝒆 𝒕𝒓𝒂𝒗𝒆𝒓𝒔𝒆
Correction to Departure of any side =
𝑻𝒐𝒕𝒂𝒍 𝒆𝒓𝒓𝒐𝒓 𝒊𝒏 𝑫𝒆𝒑𝒂𝒓𝒕𝒖𝒓𝒆 × 𝑳𝒆𝒏𝒈𝒕𝒉 𝒐𝒇 𝒕𝒉𝒂𝒕 𝒔𝒊𝒅𝒆
𝑷𝒆𝒓𝒊𝒎𝒆𝒕𝒆𝒓 𝒐𝒇 𝒕𝒉𝒆 𝒕𝒓𝒂𝒗𝒆𝒓𝒔𝒆
2. Transit Method:
This method is used to balance the traverse when angular measurements are
taken more precisely than linear measurements during field observations. The
error in latitude and departure is distributed in proportion to the latitudes and
departure of the sides.
Correction to Latitude of any side =
𝑻𝒐𝒕𝒂𝒍 𝒆𝒓𝒓𝒐𝒓 𝒊𝒏 𝑳𝒂𝒕𝒊𝒕𝒖𝒅𝒆 ×𝑳𝒂𝒕𝒊𝒕𝒖𝒅𝒆 𝒐𝒇 𝒕𝒉𝒂𝒕 𝒔𝒊𝒅𝒆
𝑻𝒐𝒕𝒂𝒍 𝒔𝒖𝒎 𝒐𝒇 𝒍𝒂𝒕𝒊𝒕𝒖𝒅𝒆 𝒐𝒇 𝒕𝒉𝒆 𝒕𝒓𝒂𝒗𝒆𝒓𝒔𝒆
Correction to Departure of any side =
𝑻𝒐𝒕𝒂𝒍 𝒆𝒓𝒓𝒐𝒓 𝒊𝒏 𝑫𝒆𝒑𝒂𝒓𝒕𝒖𝒓𝒆 ×𝑫𝒆𝒑𝒂𝒓𝒕𝒖𝒓𝒆 𝒐𝒇 𝒕𝒉𝒂𝒕 𝒔𝒊𝒅𝒆
𝑻𝒐𝒕𝒂𝒍 𝒔𝒖𝒎 𝒐𝒇 𝑫𝒆𝒑𝒓𝒕𝒖𝒓𝒆 𝒐𝒇 𝒕𝒉𝒆 𝒕𝒓𝒂𝒗𝒆𝒓𝒔𝒆
 We applied Bowditch’s method to balance the major traverse.
Calculation of Independent coordinate:
Coordinate (Easting) of New point = Coordinate (Easting)of known point +
Length of side × sin(bearing of sides)&
Coordinate (Northing) of New point = Coordinate (Northing)of known point +
Length of side × cos (bearing of sides)
Example, Coordinate of pt. B is, EB = EA+ 𝐿 × sin θ
NB = NA+ 𝐿 × cos θ
2.5.8.1.2 Plotting:
Knowing X, Y & Z (Easting, Northing & Elevation) co-ordinates of traverse points,
traverse was plotted on drawing paper. Major traverse was plotted in scale of 1: 500 &
minor traverse in scale of 1: 500. Plotting of balanced traverse was done and was
plotted as,
1. The co-ordinates of traverse stations were listed.
2. The maximum Northing & Minimum Northing was noted.
3. The required length for plotting was computed (Max. Northing - Min.
Northing).
4. The available length in N-S direction (Length between upper side & lower side
of drawing sheet) was measured.
5. The difference between available length & required length (4-3) was
calculated. It gave us the total margin on drawing sheet.

30
6. Now the margin had given at Top & Bottom equal to half of the total margin
(5/2).
7. Now the suitable value of co-ordinate at starting point of Northing was
selected.
8. Similarly, the maximum Easting & minimum Easting was Noted, required
length in E-W direction was computed, available length in E-W direction was
measured, the difference between available & required length was computed to
compute the total margin, the margin was given at left and right side equal to
half of the total margin & finally the suitable value of co-ordinate is selected at
starting point of Easting.
9. Now plotting of balanced major traverse was done.
2.5.8.2 Computation and Plotting of Minor Traverse
 Bearing of sides CP1-CP2, & 4M13-4M14 were noted down (from major
traverse gales table; adjusted bearing).
 Observed horizontal angle <CP1 CP2 4m1, <CP2 4m1 4m2, <4m1 4m2 4M13 &
<4m2 4M13 4M14 were noted.
 The bearing of CP2 4m1, 4m1 4m2,4m2 4M13, & 4M13 4M14 were computed.
 Difference between calculated bearing & adjusted bearing of side 4M13-4M14
was angular misclosure for minor traverse.
 The permissible angular misclosure for minor traverse was calculated (1'√N).
 The angular misclosure was found to be less than permissible angular misclosure
Cumulative method of bearing correction:
Error of closure = e, Number of minor traverse station, n'=2 So, no of lines which
bearing was to be corrected, n= n'+2=4 = no of traverse station (two major and minor)
Adjustment ( correction ) in 1st
line =
×
Adjustment ( correction ) in 2nd
line =
×
Adjustment ( correction ) in 3rd
line =
×
Adjustment ( correction ) in 4th
line =
×
Then we had corrected bearing and length of minor traverse sides.
 Latitude & Departure of minor traverse sides was computed. The Algebraic sum
of all Latitudes & Departure was also computed.
 The true difference in Latitude & Departure was computed by subtracting
Latitude & Departure of Station CP2 from 4M13.
 Error was computed (7-8), and was found within permissible error.

31
 Then the Latitude & Departure of minor traverse side was balanced by applying
Bowditch method.
 Then the independent coordinate (Total coordinate) of minor stations was
calculated with respect to independent coordinate of major traverse station CP2.
 Then the minor traverse was plotted similarly as major traverse.
2.5.9 Contouring
A contour is defined as an imaginary line passing through the points of equal
elevation. Thus contour lines on a plan illustrates the configuration of the ground. The
method of representing the relief of the ground by the help of contour is called
contouring. The vertical distance between twoconsecutive contours is called contour
interval. Every 5th
contour which is 5 times of the contour interval is the index
contour which is generally darkened in the contour and is known as Index Contour.
The least horizontal distance between two consecutive contours is called the
horizontal equivalent.
Methods of contouring
There are two ways of contouring. They are namely
1. The Direct method
2. The Indirect method
1. The direct method:
In this direct method, the equal elevated points are joined. For this, firstly the points
with the same elevations are found out by setting out the instrument at a point and by
hit and trial method of searching the points which gives the same required staff
reading.
2. The indirect method:
In this method, some suitable guide points are selected and surveyed, the guide points
need not necessarily be on the contours. There are some of the indirect methods of
locating the ground points:
a. By squares
b. By cross-sections
c. By tacheometric method
Contour Interpolation
The process of drawing contours proportionately between the plotted ground points or
in betweenthe plotted contours is called interpolation of the contours. Interpolation of
contours between points is done assuming that the slope of ground between two
points is uniform.

32
It may be done by anyone of following methods.
 Estimation
 Arithmetic calculation
 Graphical method
Contour Characteristics
 Two contour lines do not intersect each other except in the case of
overhanging cliff.
 A contour line must close onto itself not necessarily within the limits of a
map.
 Contours of different elevations do not unite to form one contour except in
the case of avertical cliff.
 Two contour lines do not unite to form a single one except in the case of
perpendicularcliff.
 Contours drawn closer depict a steep slope and if drawn apart, represent a
gentle slope.
 Contours equally spaced depict a uniform slope. When contours are parallel,
equidistant and straight, these represent an inclined plane surface.
 A set ring contours with higher values inside depict a hill whereas a set of
ring contours with lower values inside depict a pond or a depression without
an outlet.
 When contours cross a ridge or V-shaped valley, they form sharp V-shapes
across them. Contours represent a ridge line, if the concavity of higher value
contour lies towards the next lower value contour and on the other hand
these represent a valley if the concavity of the lower value contour, lies
toward the higher value contours.
 The same contour must appear on both the sides of a ridge or a valley.
 Contours do not have sharp turnings.
2.5.10 Output
 Topographical map of the given area.
 Major traverse
 Minor traverse
2.5.11 Comments and Conclusion:
The given topography survey camp work was finished satisfactorily within the given
span of time. The subject survey needs practice as much as possible. The site for the
survey camp was suitable for us to practice the theoretically acquired knowledge in
the field. Laying control stations, carrying out level works and angular measurement
became difficult while laying stations on jungle side. The obstructions due to trees

33
created problem. The work was slowed down as some of the instruments provided
were with errors. In surveying, theory can be taken only as the introduction but if
there is practice, there will be much gain of knowledge about the techniques of
surveying. The subject survey needs practice as much as possible. Thus, this camp
helps us by practicing the survey work to gain the much essential knowledge as far as
possible. It is better to say that it provides us a confidence to perform survey and
apply the techniques at any type of problem facing during the actual work in the
future career.
All the groups prepared their topography map of the given area of Mars survey camp
in the same scale. The whole area was divided in such a way that area allocated for
one group contains some part of the area allocated for another group. One traverse leg
is common to all groups and hence the combination of all groups effort will provide a
perfect and complete topographic map of Mars survey camp after combining it.

34
CHAPTER – 3
BRIDGE SITE SURVEY
3.1 Introduction
Bridges are the structures that are constructed with the purpose of connecting two
places separated by deep valleys or gorges or rivers and streams. Bridges are usually
the cross drainage and hence a part of roads making them shorter and hence
economical. In areas characterized by uneven terrain and numerous water bodies,
bridges represent a cost-effective and efficient solution, offering a convenient means
of connectivity. The major goal of this survey is to propose the best location for
bridge axis. Topographic survey of the proposed bridge site needs to be carried out to
present the geography of that area by plotting contour lines. Both horizontal and
vertical control is carried out to obtain N, E. and Z co-ordinates. In most of the cases,
the horizontal control in bridge site survey is carried out by Triangulation. It is
because at such places only narrow strip like land is available where setting out chain
of interconnected triangles would be easier can traversing.
In this survey, we had to:
 Decide the best possible alignment for a bridge to be constructed across the
river.
 Determine the bridge axis.
 Take sufficient data to get the length of the bridge proposed.
 Take data for L-section, X- Section of river upstream and downstream for the
bridge axis to study the properties of river, like – discharge of water, bed
slope, velocity of water etc.
 Take spot heights of area around the bridge axis for preparation of topographic
map.
3.2 Objectives
The main objective of the bridge site survey is to give the students the preliminary
knowledge on selection and planning of possible bridge site and axis for the future
construction of the bridge. The purpose of the bridge site survey was not only to
prepare plan and layout of the bridge site but also from the engineering point of view,
the purpose is to collect the preliminary data about the site such as normal water flow
level, high flood level, geological features of the ground for planning and designing of
the bridge from the details taken during the surveying. Moreover bridge construction
is an important aspect in the development of transportation network. Surveying is
required for topographical mapping, knowledge of longitudinal sections of the river
and cross sections at both the upstream and in downstream side of the river for the
construction of a bridge.

35
3.3 Brief Description of the area
The hill slopes on one side was steep but very compacted soil and another side was
not very steep and are thus geologically stable. The trees and shrubs maintain the
greenery of the area. There are only few houses near the bridge site. Very few locals
were seen rearing their cattle around the grassy lands of the area. As rainfall barely
occurs in winter season, the site was drier than expected, there is not much water to be
found on the bridge site. The only water is collected from rain and other sources.
3.4 Hydrology, Geology and Soil Condition
The river channel is fully dry due to no precipitation and lack of natural spring source.
The river has a cross slope and is really deep. Deep in the sense that the river banks
are at extremely higher elevation than the channel bottom. The gentle slope of channel
bed, large width of channel, and less water available for surface runoff suggests that
the depth of water is normally less and the water flows under less velocity.
About geology, the proposed location had steep yet stable slopes. Some rocky
exposures and large blocks of rock could be seen around the centerline of the river.
The western bank of the river had dry soil as it faced the sun directly. On the contrary,
the eastern bank is a sloppy land facing away from the sun which must be why it is
always damp and moist. The width of stream is not so big but high flood level covers
large area. Water scoured marks on the sides show that HFL is about 5m below either
of the bank.
3.5 Technical Specification (Norms)
A bridge site topographical survey was carried out and the alignment of the bridge
axis was fixed by triangulation. Along with these we were also supposed to read L-
section and X-section of the river downstream and upstream. A topographic map was
prepared by tacheometric surveying and longitudinal and cross-sectional profile of the
area was drawn.
The following norms were followed while performing the bridge site survey in the
field:
 Control point fixing as well as determining the length of the bridge axis
had to be done by the method of triangulation. While forming triangles,
proper care had to be taken such thatthe triangles were well conditioned,
i.e., none of the angles of the triangle were greater than120° or less than
30°.
 In triangulation, distance of Base Line must be measured in an accuracy
of 1:2000.
 The triangulation angle had to be measured on two sets of readings by
theodolite and the difference between the mean angles of two sets of
readings had to be within a minute.
 Carry out reciprocal levelling to transfer level from one bank to other

36
bank of the river within a precision of ±24√k mm. Determine the RL of
the other triangulation stations by fly levelling from the end point of
bridge axis.
 The scale for plotting the topographical map was given to be 1:500. In
order to plot the longitudinal section of the river; data had to be taken
along the river bed up to 150m upstream and 50m downstream.
 The scale for plotting are as follows:
Scale of topographic map =1:500
Scale of L-Section:
Horizontal Scale = 1:1000
Vertical Scale = 1:100
Scale of Cross Section:
Horizontal Scale = 1:100
Vertical Scale = 1:100
3.6 Equipment and Accessories
 Theodolite
 Ranging Rod
 Levelling instruments
 Marker
 Arrow
 Staffs
 Compass
 Tapes
 Pegs
 Hammer
 Tripod
3.7 Methodology
The various methods performed during the bridge site survey were site selection,
triangulation, leveling (fly levelling and reciprocal levelling), detailing by total
station, cross section, and L-section. Triangulation was adopted to perform the
horizontal control of the bridge site. For this angle measurement was done using
Theodolite and distance measurement was done using Measuring Tape. Fly levelling
using auto level was conducted to transfer RL from one to other stations on same
bank of the river. Reciprocal Levelling was done to transfer RL between two points of
bridge axis across the river. Detailing was done using Tachometer. Contour Map of
the site was plotted. From the map, L-section and X-section of the river channel was
extracted using CAD software. The brief descriptions of these methodologies are
given below:

37
3.7.1 Reconnaissance
The first step of bridge site survey was to select the site to find where it can be
located. Inspection of whole area was done by walking all over the site and
preparation of Index Sketch (Showing number and position of Triangulation station
with important field details around the Bridge Site) in A3 size paper. It should not
have selected in the bending portion and at least 100m straight portion upstream and
downstream. And station for the triangle was selected in such a way that it formed the
well-conditioned triangle.
3.7.2 Site Selection
The selection of bridge is an art and requires considerable investigation. There are
various factors for the selection of bridge site such as geological condition, socio-
economical and ecological aspect etc. It is one of the costliest infrastructures that
promotes economic and social life of people. It is like the missing link of the chain
where chain means major highways. Bridge must be strong, stable, and must fulfill
the purpose of its construction. For that it must be built at the best possible location.
Hence, site selection is the integral step which must be professionally conducted prior
to any bridge construction process. Geological conditions of site should be sound and
stable. Presence of bed rocks near the bridge site makes it more favorable. It must not
be selected in built up areas and the site should have well defined banks. The river
channel near the site should not be meandering rather straight. The elevation
difference between two opposite points of bridge axis should be less than 1m so as to
reduce the cost of cutting and filling during the actual construction process. The
proposed bridge axis should be perpendicular to the river flow. The preference for
shorter spans is high as the cost of construction gets reduced. Apart from that, the
construction of bridge must not hamper the ecological balance between the flora and
fauna of the site. The bridge location should be impartial to any social or economic
groups of people.
Therefore, the site was chosen such that it is laid on the very stable rocks at the bed of
river as far as possible and not affect the ecological balance of the flora and fauna of
the site area. The location of the bridge was selected in such a way that the heights of
the roads joined by the proposed bridge were almost the same. This prevented a lot of
cutting and filling to maintain a gentle gradient. The bridge site was chosen in such a
way that the bridge axis was perpendicular to the flow direction and was also shorter
in span so as to make the construction economical. The starting point of bridge axis
was not laid on the curve of the road.
Keeping in minds the above factors, the bridge site was selected. For the purpose of
the shortest span, the stations were set perpendicular to the river flow direction. The
river banks were not eroded and were suitable for bridge construction. The chance of
direction of river on the selected axis line was nominal.

Survey Camp Report (Mars Nepal Engineering Survey Camp)

Survey Camp Report (Mars Nepal Engineering Survey Camp)

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