Survey camp For IOE III/I

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SIGNATURE PAGE

I certify that I have this report and in my opinion, it is satisfactory in scope and quality as a partial fulfillment of the requirement for the Bachelor’s Degree in civil engineering third year first part held at two different locations namely Baluwakhani for bridge survey and Budhanilkantha School for topographic and road survey held from 20^th to 30^th Ashwin 2074.

……………………………

Er. Bimal Bhattarai

(Camp coordinator)

Preface

This report is the outcome of the "Survey Camp 2074" organized by Survey Instruction Committee, Department of Civil Engineering of Kathmandu Engineering College for the students of 072 BCE Batch, as part of the curriculum for the subject of Survey Camp prescribed by Tribhuvan University, Institute of Engineering. The camp was held in Budanilkantha School for a total of 10 days and entailed the practical application of the knowledge acquired during the second year on the subject Surveying I &II for two consecutive semesters.

The report reflects the methodology, observations and calculations made by the students in the Camp with the corresponding drawings. The large portion is of course covered with elements of topographic surveying, and then those of road alignment and bridge survey follow it.

The survey camp promoted team work, proper handling of instruments and responsibility of field and office work simultaneously. Also, it strengthened our capabilities in major and minor traversing, RL transformation, detailing and preparation of topographic map, setting out of curve, road and bridge site survey. Moreover, it developed our confidence on the subject.

This report is the result of hard work and dedication put forward by the students who thrive for knowledge and new ideas. Thus we feel it deserves the tolerances and excuses for the error or blunders present, despite the best efforts.

Group 2

Hemant Adikhari

Krishna Kamal Sah

Nabindra Chalise

Prawal Shrestha

Rajesh Kaji Shrestha

Acknowledgements

This report is the outcome of the survey camp 2074 conducted by the Survey Instruction committee, Kathmandu Engineering College. Thus, we like to express our deep gratitude to the Survey Instruction committee, Department of Civil Engineering, KEC, for organizing the survey Camp-2074 for 2072 BCE Batch.

We have our special thanks to our teacher Er. Bimal Bhattarai (Survey Co-ordinator) for his decent coordination which was praiseworthy. We found all of our teacher's very hard working, devoted to one’s task, loving, caring and very determined. We got great inspiration from their company. They were ever available to us, anywhere, to clear out the lagging concepts and guide us from deviating.

We would like to thank Er. Shishir Rijal (Survey Sub Co-ordinator), Er. Bikash Raj Joshi (Survey Sub Co-ordinator), Er. Arjun Poudel, Er. Harsikesh Karn, Er. Rama Thapa, Er.Sagar poudel ,Er.Suresh Thakuri, Er. Tirtha raj karki, Er. Rajan Nemaphuki and Er. Ishwar Adhakari who were supportive and played a key role in successively completing the survey camp.

We would also like to thank the survey camp staffs Mr. Ganesh Raj Basaula, Mr. Deepak Raj Upreti, Mr. Deepak Shrestha, Mr. Bhagwan Thapa , Mr. Buddhi Ram Chaudhary for their great help during the camp.

Our heartily thanks goes to all others seniors and individuals who helped and guided us with the experience they had, for preparation of survey report. We would also like to thank all the staffs of Budhanilkantha School for helping us stay at the camp site.

The camp was over with total success, and we have found it really fruitful.

TABLE OF CONTENTS

Signature page

Preface

Acknowledgement

Salient of contents

Camp Working Time Schedule

Camp Working Time Schedule Detail

SECTION –I

CHAPTER 1: INTRODUCTION

1.1	Objective of survey camp
1.2	Project area
1.3	Location and accessibility
1.4	Topography and geology
1.5	Rainfall climate and vegetation
1.6	Others

CHAPTER 2: TOPOGRAPHIC SURVEY

2.1 Objective

2.2 :brief description of the area

2.3 norms(Technical specification)

2.4 Equipment

2.5 methodology

2.5.1 Reconnaissance

2.5.2Major traverse

2.5.3 minor traverse

2.5.4 levelling

2.5.5 two peg test

2.5.6 contouring

2.5.7 computation and plotting

2.6 comments and conclusion

CHAPTER 3: BRIDGE SITE SURVEY

3.1 objectives

3.2 Brief description of the area

3.3 hydrology and geology of soil

3.4 technical specification

3.5 Equipment and Accessories

3.6 Methodology

3.6.1 site selection

3.6.2 topographic survey

3.6.3 longitudinal section

3.6.4 Cross section

3.6.5 levelling

3.6.6 detailing

3.6.7

3.7 comments and conclusion

CHAPTER 4: ROAD ALIGNMENT

4.1 Brief description of the project area

4.2 hydrology and geology

4.3 soil

4.4 norms

4.5 Equipment and accessories

4.6 design parameters

4.7 Methodology

4.7.1Reconnaissance

4.7.2 Horizontal alignment

4.7.3 Vertical alignment

4.7.4 Levelling

4.7.5Longitudinal section

4.7.6 Cross section

4.7.7 topographic survey of road

4.8 STRUCTURES

4.8.1 retaining structure

4.9 curves

4.10 comments and conclusion

SECTION-II

1. TOPOGRAPHIC SURVEY

· DATA AND CALCULATION

· MAPS AND GRAPHS

2. ROAD ALINGMENT

· DATA AND CALULATION

· MAPS NAD GRAPH

3. BRIGGE SITE SURVEY

· DATA AND CALULATION

· MAPS NAD GRAPH

SALIENT FEATURES

Name of the project: Survey Camp 2074

Description of the project:

Location:

1. Region: Central Development Region

2. Zone: Baghmati

3. District: Kathmandu

4. MUNCIPALITY : Budhanilkantha MUNCIPALITY

Latitude:	27⁰46' 55.52"N
Longitude:	85 ⁰21' 34.2" E

Site: Budhanilkantha School for detailed survey and road survey and a Pipalbote Kholsa at

Baluwakhani, Kapan for bridge surveying.

Geographical features:

l. Terrain: Hilly

2. Climate: Mild temperature

3. Geology: Plains and hills composed of soils and rocks

4. Vegetation: Good

Descriptions of works:

Traversing:

1. No. of major traverse stations :22

2. No. of minor traverse stations: 11

3. No. of minor loops: 1

4. Length of perimeter:1226.032

5. Longest leg length: 79.416m

6. Shortest leg length:44.108m

Details of the data taken are in the observation sheets.

Scale:

Topographic Map:1:500

Major and minor traverse:

Contour Interval: 1m

Detailing:

Area: The minor traverse cover the LRC and Boys Hostel and football ground

Road alignment.

1. Road type: Village Road

2. Surface: Earthen

3. Length of road: 604.570m

4. No. of intersection points:10

5. Cross section: 10m left and 10m right of both sides of center line.

6. Longitudinal section: in every 20m of the length.

Details of the data taken are in the observation sheets.

Scale:

• Topographic Map: I :500

• Longitudinal section: Horizontal=1:1000

Vertical = 1:100

• Cross section: Horizontal = 1:100

Vertical = 1:100

• Contour interval: 1m

Bridge Site Survey:

I. Bridge Span:

2. Cross Section: 120m on upstream and 50m on downstream at 25m interval. Details of the data taken are in the observation sheets.

Scale:

Topographic Map: 1:500

Longitudinal section: Horizontal = 1:500 Vertical = 1:50

Cross section: Horizontal : 1:100

Vertical = 1:100

Contour interval: 1m

DATE	Description of work
20^th Ashwin,2074	Reconnaissance and major traverse
21^th Ashwin,2074	Major traverse computation
22^th Ashwin,2074	Minor traverse computation
23^th Ashwin,2074	Two peg test and fly levelling
24^th Ashwin,2074	Bridge site survey (racy and horizontal angle measurement)
25^th Ashwin,2074	Bridge site (detailing with theodolite)
26^th Ashwin,2074	Road alignment
27^th Ashwin,2074	Detailing of road alignment
28^th Ashwin,2074	Detailing of major traverse
29^th Ashwin,2074	Detailing of minor traverse and and field verification

CAMP WORKING SCHEDULE SUMMARY

Descriptions of the work done on the respective days:

20^thAshwin 2074

We were given brief description of the area by our teachers and guided us for reconnaissance of the area for fixing Major control stations. The major control points were fixed fulfilling the required norms, following the referencing. Then two-way measurement of traverse legs was done.

21^thAshwin 2074

For the traverse formed, horizontal and vertical circle readings were taken. Two sets of horizontal readings were taken and one for vertical reading.

22^thAshwin 2074

Reconnaissance followed by marking and fixing the minor stations was done enclosing the assigned area so as to achieve maximum details. Referencing, two-way distance measurement was done. Internal angle measurement was done by total station.

23^thAshwin 2074 Two peg test was carried out to find out collimation error in provided auto level. Fly levelling was done form BM at Budhanilkantha Temple premises to TBM established inside Budhanilkantha School and was checked if it was under the precision or not. After that, the RL transfer was done from TBM to all the major stations.

24^thAshwin 2074

We were taken to the site of Bridge Survey, Kapan, Baluwakhani. After reconnaissance bridge axis was selected and triangulation stations were fixed such that all stations were visible from base stations and well-conditioned triangle was formed. The necessary angular measurement was done by total station and base lines was measured by tape. We worked on bank opposite to bank with TBM. Details were taken from stations on this bank.

25^thAshwin 2074

On this day, we worked on bank containing TBM. The necessary horizontal circular and vertical readings were taken by theodolite. Base length was measured by tape. Tachometric detailing was carried by theodolite and staff. The left details were taken alone with deepest points reading along cross section. The bearing of line joining stations

26^thAshwin 2074

Teachers instructed us on alignment of road and mentioned all the norms to be achieved on the first day, Cross sections details were taken on every 20m interval and at tangent points and mid points of the curve.

27^thAshwin 2074

The road was ended to major station ZM20 by the end of the day and all the necessary details were taken during the work. The RL transfer was carried out of all the road stations.

28^thAshwin 2074

The detailing of minor traverse was carried out with the help of total station. The field verification of the major and minor traverse was plotted in grid sheet.

29^thAshwin 2074

Remaining work of detailing was done with the help of theodolite.

30^thAshwin 2074

Compilation of all the data were done and checked if any data's have been missed. On completing the field work, we returned from the survey camp.

INTRODUCTION

Surveying is an art and science of determining the relative position of point on above or beneath the surface of the earth surface and presentation of this information either graphically or numerically by means of angular and linear measurements. It is the most important subject matter before and during all engineering works like civil engineering works such as designing and construction of highways, water supply systems, irrigation projects, buildings etc. as all these works require preliminary and detail designs for which the knowledge of surveying is the essential factor to be considered.

Surveying is the backbone or the preliminary task for the execution of any civil engineering projects. The science of surveying has been developing since the very initial stage of human civilization according as per requirements. The art of surveying and preparation of maps has been practiced from the ancient times and further the advancement till present. The objective of survey is to prepare plan or map so that it may represent the area on the horizontal plane. A plan or map is the horizontal projection of an area and shows only horizontal distances of the points. Vertical distances between the points are, however, shown by contour lines. In the absence of map, it is impossible to layout the road alignment, canals, tunnels, transmission power lines etc. Detailed map or topographical map of the site is essential for any engineering project is based upon the accurate and complete survey work.

The main objectives of surveying courses allocated for civil engineering students is to promote them the basic knowledge of different surveying techniques relevant to civil engineering works in their professional practice. The completion of all surveying courses including ten days survey camp work organized by the Department of Civil Engineering, “Survey Instruction Committee” of Advanced College of Engineering and Management , give better enhancement to students to use all surveying technique covered in lecture classes. It also build student’s confidence to conduct engineering survey or necessary field works by own decision on planning and execution of field works as per the required accuracy by using allocated instruments and in allocated schedule.

The B.E. third year students of 2072 batch comprising 121 students; were on 10 days survey camp dated from 20^th Ashwin to 30^th Ashwin of 2074 in Budhanilkantha,school, budhanilkantha ,Kathamndu, Nepal organized by the Survey Instruction committee, Kathmandu College. The survey camp was taken as a part of course of 4-year Civil engineering course. It gives an aid to fulfill the main objective of surveying i.e. to produce the best & perfect civil engineers.

As the works to be conducted during the field works are all team works, all the field works during the camp were performed in-group. The camp has in fact, developed the ability to make quick decision, planning, execution etc. of the field works in students. Overall, the survey camp helps to give a lot of information for conducting actual engineering survey in the field.

This is a detail report of the works, which were performed by group no. 2, having five members, during the camp period. It briefly explains the working procedures and technique used by this group during that camp period. In addition, it also contain observations, calculations, methods of adjustment of error, main problem faced during work and their solution, results of all calculations and their assessments with some comments is presented in a concise form.

1.1 OBJECTIVES OF SURVEY CAMP

Only theoretical knowledge on surveying is not sufficient for the students to tackle any type of problems in the real field in effective manner. So to provide a good practical knowledge on the field, a survey camp is designed in 3^rd year 1^st part of Bachelor in civil engineering.

The main objectives of survey camp are summarized as follows:-

· To become familiar with the survey problems arise during field works.

· To become familiar with the parts of instruments, their functions and handling the surveying instruments for its use in surveying.

· To promote team working and sharing responsibilities of the same work by each individual in their own way to complete the project work within the allocated time.

· To enable students in selecting the Bridge axis with proper location, to prepare L-section and X-section of waterway and topographical map of Bridge site.

· To collect the required data in the field in systematic ways, to analyze, calculate & to plot.

· To compute & manipulate the observed data in the required accuracy and present it in diagrammatic and tabular form that other engineer can understand it easily.

· To make connection of theoretical knowledge with actual field condition, to solve field problems in the best way with reasonable time, cost and accuracy.

To complete the given project in scheduled time and thus knows the value of time.
To tackle the mistake and incomplete data from the field while in office work.
To know the complete method of report preparation.

1.2 SALIENT FEATURES OF THE PROJECT

Description of the project

Topographic map preparation

· Scale: Major traverse 1:1000

Minor traverse 1:500

· Paper size for plotting: A₀

· Contour interval: 1m

Control point establishment

· At least 1 stations (Main control station)

Major stations: 21

Minor stations: 11

· Two set of horizontal angle (Major)

· One set of horizontal angle (Minor)

· Two way measurements (1:2000 accuracy)

· Fly leveling (±25√k mm accuracy)

· Leg ratio (Minimum to maximum traverse leg distance)

Major 1:2

Minor 1:3

Special techniques of surveying

· Detailing by total station

Road alignment survey

· More than 600m chainage

· Plan 1:500

· Longitudinal section ; scale= V- 1:100 or 50 & H- 1:1000 or 500

· Cross section: 15 m interval, scale: H=V=1:100 or 1:200

· Left right observation: 10m on either side

Curve setting

· Horizontal curve by both linear and angular method

Bridge site survey

· Up-stream: At least 150m

· Downstream: At least 50m

· Number of stations: 6

· Scale for topographic map: 1:500

· Contour interval: 1m

· Cross section: every 25m interval, scale: H=V= 1:100 or 200

· L-section: V= 1:50 or 100 and H=1:500 or 1000

Leveling

Before leveling was done, two-peg test was done and corresponding correction was made. Strictly speaking, the leveling was done in three steps:

· Transfer of R.L. from B.M. to T.B.M.

· Transfer of R.L. from T.B.M to major station

· Transfer of R.L. from T.B.M to minor station

1.3 PLANNING AND ORGANIZING SURVEY CAMP

Survey camp has been designed for us for a large no. of objectives. For achieving such objectives, planning and organizing phase is one of the most important phases of the survey camp. To make the survey camp fruitful, we all students along with the teachers has planned about camping in the respective ways:

1.3.1 Group discussion among the students

Most of civil engineering in the professional fields is a team work. As one of the important objective of our survey camp is to give a professional taste towards different problem raised in the field of civil engineering, group discussion among the students help to fulfill the objectives. Firstly the group containing 5 members each is divided and all the members of the group has discussed about the responsibilities for fulfilling the given task of the group by survey instruction committee.

1.3.2 Teacher’s supervision

Survey camp has provided a platform to learn the practical knowledge and difficulties that has been arising in the scheduled time. Frequent assistance and supervision of the teachers were called out. There were sufficient teachers for guidance, assistance and supervision of the task carried out by all the groups.

1.3.3 Time duration of the camp

Total time duration of the camp of the 10 days. Out of which 5 days was allocated for topographic survey, 1 day for two peg test and fly leveling, 1 day for R.L. transfer to the major and minor traverse stations from TBM, 1 and half day for bridge site surveying and another 1 and half day for road alignment survey.

1.3.4 Daily scheduling of different activities

To perform the specified task in a well-planned manner and reduce the problem of scarcity of equipment required for the specified task, the daily work schedule was listed below:

1.3.5 Transportation facility at the camp

The daily scheduling of the tasks were from 7:00 A.M. in the morning till 5:30 P.M. in the evening. The camp was held in the premises of Budhanilkantha school, which was easily accessible through the means of transportation.

1.2 PROJECT AREA

Budhanilkantha School,Nepal

1. 3LOCATION AND ACCESSIBILITY

1.3.1 Location

Budhanilkantha is municipality situated in a valley at about 1444.375m above sea level in the central Nepal.

Country: Nepal

Development region: Central

Zone: Bagmati

District: kathmandu

Municipality: Budhanilkantha Muncipality

Location: budhanilkantha school

1.5.2 Accessibility

Budhanilkantha School, often referred to as BNKS, is a public boarding school in Nepal. It is located in Narayansthan, 8 kilometres north of Kathmandu on the foothills of Shivapuri mountain (2,732 metres).^[1] It is named after the Budhanilkantha Temple which is located nearby

1.4 TOPOGRAPHY AND GEOLOGY

Before starting our job, we should study about the existing position of the project area related to the natural grid line so that we can relate our result into the natural grid.

The latitude and longitude of budhanilkantha schoolare as follows:

Latitude: 27° 46' N

Longitude: 85° 211' E

Terrain: Steep slope

1.5 rainfall climate and vegetation

Climate: Mild/Sub - tropical

Temperature: Max. 35° C in summer

Min. 10° C in winter

Rainfall: Adequate

Geological zone: Lesser Himalaya Zone

1.6 OTHERS

Budanilkantha, situated at the foot of Shivapuri hill, was a Village Development Committee in Kathmandu District in the Bagmati Zone before being incorporated into the city of Budhanilkantha (along with Chapali Bhadrakali, Mahankal, Bishnu, Chunikhel and Kapan). At the time of the 2011 Nepal census it had a population of 15,421.^[1]The whole area was sub-divided into various parts where the almost area covers educational buildings. The main buildings are teaching block A and B, hostel block, multipurpose building and quarters. Along with these buildings, it has basketball court, football ground.

2. TOPOGRAPHICAL SURVEY

2 INTRODUCTION

Topographic surveying is the process of determining the positions, both on the plan and elevation, of the natural and artificial features of a locality for the purpose of delineating them by means of conventional signs upon a topographic map. By topography the shape or the configuration of the earth’s surface can be known. The basic purpose of the topographic map is to indicate the three dimensional relationships for the terrain of any given area of land. Thus, on a topographic map, the relative positions of any given points are represented both horizontally as well as vertically.

2.1 OBJECTIVES

The main objective of the topographic survey is to prepare the topographic map of the given area with horizontal and vertical control at required accuracy. By topographical survey we can determine the positions both on plan and elevation, of the natural and artificial features of a locality for the purpose of delineating them by means of conventional sign upon a topographic Map. Apart from this, some of other objectives are summed-up as follows:

· Use and become familiar with different kinds of surveying instruments.

· Selection and use of appropriate methods to perform the topographic survey.

· To provide accurate control points for plane tabling, tacheometry and detailing.

· To fix the alignment of roads, bridges, canals, channels etc.

· To determine the relative position on or beneath the surface of the earth.

· To layout the position of any structural and natural objects.

· To prepare the relief maps this enhances its utility.

2.2 BRIEF DESCRIPTION OF THE AREA

The school was established in 1972. The school covers about 29 hectares (574 Ropanies) of land. It is a full boarding school for students from 5th grade to A-Level, aged 10 to 19. The school is equipped with three full size multi-purpose sports field, a swimming pool, assembly hall, dining hall, sports hall, Learning Resource Center, library with Wi-Fi internet, modern science labs and living quarters for its faculty. The students come from all over Nepal.

Teaching Block A

i) Boys hostels

ii) LRC

iii) Football ground

iv) Basketball Court

These buildings and the important ground features are included between the minor traverse provided with one link traverse and four legs of major traverse.

2.3 NORMS (TECHNICAL SPECIFICATION)

1) Reconnaissance of the area: Reconnaissance survey of the given area should be conducted. A closed traverse (major and minor) around the given area should be formed by establishing the traverse station. Note that the ratio of maximum traverse leg to minimum traverse leg should not exceed 2:1for major leg and 3:1 for minor legs with accuracy of 1:2000 and 1:1000 respectively in linear measurements.

2) Establishment of Horizontal control and Vertical control: Horizontal and vertical controls of the given area must be determined based upon the given horizontal datum and vertical datum. Co-ordinate of CP is given to be (X, Y) and Z co-ordinate must be transformed from BM by means of fly leveling.

3) Two way measurement: Two way measurement of the traverse leg should be done by the means of total station. Accuracy of two way measurement in case of both major and minor leg must lie within 1:2000.

4) Measurement of Horizontal Angle: Two sets of angle measurement must be done using total station. The difference of the two face reading should not be more than ±180⁰+twice the least count or circle reading. It should be noted that the difference between the mean angles of two set reading should be within a minute.

5) In case of minor traverse, measure only one set of horizontal angle and the difference of the two face reading should not be more than ±180⁰+twice the least count or circle reading.

6) Determination of RL of traverse stations: This must be done using fly leveling (three wires) from the given BM (Vertical Control Station) after completion of the Two Peg Test. Accuracy in the case of Two Peg Test should not be less than 1:10000. Balancing of back sight and fore sight for the elimination of different types of error including collimation error. The permissible error of fly leveling is ±25 mm where K is distance covered in km.

7) Adjustment of traverse: The theoretical sum of interior angles in a closed traverse should be equal to (2N-4)*90⁰. The permissible angular error or the angular misclosure for the sum of interior angles of the traverse should be less than ± minutes for major traverse and ±1.5 minutes for minor traverse, where N is the number of sides and n is number of station. The relative closing error should be less than 1:2000 and 1:1000 for major and minor traverse respectively.

8) Plotting of traverse: Plotting of the traverse stations is done by co-ordinate method selecting appropriate scale, 1:1000 for the major traverse and 1:500 for the minor traverse.

9) Drawing the contour lines: The contour lines are drawn with the contour interval of 1m on the map with the help of sufficient guide points.

2.4 EQUIPMENTS

The following equipment’s were used in the topographic survey:

i) Total station with accessories

ii) Staffs

iii) Ranging rods

iv) Tapes

v) Leveling instrument with accessories

vi) Compass

vii) Auto level with tripod

viii) Arrows, pegs, hammer Paints /Markers and plumb bobs.

TRAVERSING

Traversing is that type of surveying in which a number of connected survey lines form the frame work, which is used for housing, factory sides, and determination of perimeter of lake, setting out and detailing of many engineering works. The main purpose of traversing is to find control points. When there is large extend of chaining triangulation, generally traversing is used. It is the method of control survey.

The survey consists of the measurement of

i. Angle between the successive lines or bearing of each line.

ii. The length of each line.

The direction and the length of the survey lines are measured with the help of angle measuring instrument, total station. If the coordinate of first station and bearing of first line are known, the coordinates of all successive points can be computed.

Traverse is of three types:

Close traverse (loop traverse)
Open traverse
Link traverse

i. Close traverse:

If a traverse starts from a point, runs and ends on the same starting point then such traverse is called closed traverse. These types of traverse are run for a closed field survey. In this type of traverse, independent check is possible and adjustment can be done very easily.

A B

D Fig.2.1 Closed traverse C

ii. Open traverse:

If a traverse starts from a point, runs and ends at the point other than starting point is called open traverse. This type of traverse is run during the route survey like road, railway, canal, tunnel etc. In these types of traverse the error calculation and balancing is very difficult.

A (known point) C

B D (Unknown point)

Fig. 2.2 Open traverse

iii. Link traverse:

These are geometrically open but mathematically closed traverse. This type of traverse starts from a known point and ends at another known point. Also in this type of traverse the calculation and balancing of error can be done easily.

A (known point) C

B D (known point)

Fig. 2.3 Link traverse

MAJOR TRAVERSE

The whole site which was to be surveyed was enclosed by the numbers of inter-connecting survey lines forming the closed circuit or the framework joining successive major control points is known as major traverse.

2.5 METHODOLOGY

Depending upon the instrument used in determining the relative directions of the traverse lines, there are several methods of traversing such as:

1. Chain traversing,

2. Chain and compass traversing,

3. Transit tape traversing,

4. Plane table traversing,

5. Theodolite traversing.

The methodology of surveying is based on the principle of surveying. They are as follows:

i. Working from whole to a part.

ii. Independent check.

iii. Consistency of work.

iv. Accuracy required

The different methodologies were used in surveying to solve the problems arise in the field. These methodologies are as follows:

2.5.1 RECONNAISSANCE (RECCE)

The planning of work is utmost to accomplish the work without any irregularity and difficulty in the scheduled time frame or time bound. It also helps to complete the work in the systematic order and in the time bound with less effort. So for better planning, detailed inspection of the area is carried out which is known as reconnaissance survey. In other word, Reconnaissance is the exploration or initial scouting of the survey area which involves the visiting around the area, rough planning of the traverse stations and their numbers according to the area and topography of the site. It is done to get the preliminary idea of the area. During the recce, one should consider the land type, vegetation, climate and Intervisibility of stations for the detailed planning.

The following points are noteworthy for the fixing of the traverse stations:

The adjacent stations should be clearly inter-visible and cover the whole area with least number of stations as far as possible. The traverse station should maintain the ratio of maximum traverse leg to minimum traverse leg less than 2:1.

The steep slopes and badly broken ground should be avoided as for as possible, which may cause inaccuracy in tapping.
The stations should provide minimum level surface required to set up the tripod of the instrument.
The traverse line of sight should not be near the ground level to avoid the refraction.
If possible well-conditioned triangles should be formed to give good graphical intersection during plotting.

Balancing of traverse:

There are two methods of balancing of traverse: -

1. Bowditch's method

2. Transit method

I. Bowditch’s method:

In this method, the total error in the latitude and departure is distributed in proportion to the lengths of the sides. It is mostly used to balance a traverse where linear and angular measurements are of equal precision. This rule says:

Correction to latitude (or departure) of any side

= (Total error in latitude (or departure)*length of that side)

Perimeter of traverse

ii. Transit Method:

In this method, the total error in latitude & departure is distributed in proportion to the latitude & departure of its side. This rule is adopted when angular measurements are precise rather than linear measurements. This role provides correction to latitude & departure of any side.

Correction in Latitude (or Departure) of any side

= Total error in latitude or departure × latitude (departure) of that line

Arithmetic sum of latitude (or departure)

CLOSING ERROR:

In the closed traverse, at the time of plotting, if the end point of the traverse does not coincide with the starting point due to error in the measurement or any other, then it is called closing error. In the closed traverse, the algebraic sum of latitude (SL) and the algebraic sum of departure (SD) must be zero. Otherwise it is said to have closing error.

\Closing error

Balancing the traverse: -

There are different methods of adjusting a traverse such as Bowditch Rule, Transit rule, Graphical Method. Among them, Bowditch rule was used to adjust the traverse in the survey camp.

2.5.4 LEVELING

It is a branch of survey with main objective is to

i. Find the elevations of given points with respect to a given or assumed datum and

ii. Establish points at a given elevations or at different elevations with respect to a given or assumed datum.

Leveling deals with the providing the vertical controls to all the control stations for the preparations of the topographic map. Two types of leveling were performed at the site, namely direct leveling (spirit leveling) and indirect leveling (trigonometric leveling).

1. Direct leveling

It is the branch of leveling in which the vertical distances with respect to a horizontal line is determined (perpendicular to the direction of gravity). It 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 between the rod readings 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) leveling:

i. Differential leveling

It is the method of direct leveling 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 leveling is also known as fly leveling.

ii. Profile leveling:

It is the method of direct leveling 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.

iii. Cross-sectioning:

Cross-sectioning or cross leveling 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.

iv. Reciprocal leveling:

It is the method of leveling 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.

Temporary adjustment of level:

The temporary adjustment of level consists of the following steps:

1. Setting up the level: The operation of setting up includes fixing the instrument on the stand and leveling the instrument approximately.

2. Leveling up: Accurate leveling is done with the help of foot screws and with reference to the plate level. The purpose of leveling is to make the vertical axis truly vertical.

3. Elimination of Parallax: Parallax is the condition when the image formed by the objective is not in the plane of the cross hairs. Parallax is eliminated by focusing the eyepiece for distinct vision of the cross hair and by focusing the objective to bring the image of the object in the plane of cross hair. Permanent adjustment of level.

To check the permanent adjustment of level two-peg test method should be performed.

T T

M M

B B

A C B

Figure: - Two peg test

Method:

Two staffs were held at A and B of known length (about 40m). First, the instrument was setup at the middle point C and both staff readings were taken. Then the machine was held near A and both staff readings (Top, Middle, and Bottom) were taken again. Then computation was made as follows in order to check whether the adjustment was required or not.

The precision obtained was less than that of required precision of 1 in 10000. Therefore, the permanent Adjustment was done.

There are two methods of booking and reducing the elevation of points from the observed staff reading.

1. Height of Instrument method

Arithmetic Check:

∑BS-∑FS=Last R.L-First R.L

2. Rise and Fall method

Arithmetic Check:

∑BS-∑FS=∑Rise-∑Fall= Last R.L-First R.L

Among the two Methods Rise and fall method is widely used. After checking the accuracy of the level by two-peg test, fly leveling was performed the known reduced, level from the BM (benchmark) was then transferred to the given control point 1 (CP). The R.L. of the control point 1 was then found to be within the permissible error of ±25Ök mm. 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 within the permissible limits. Then the linear and angular adjustments were made in each leg. All the necessary data and calculations are presented in the following pages in this report.

2.5.5 DETAILING

Detailing means locating and plotting relief in a topographic map. Detailing can be done by either plane table surveying or tachometric surveying or by EDM. Some of the steps followed while carrying out the detail survey are summed up as follows:

· Instrument was set at each control points with accurate centering and leveling.

· The vertical distance from the center of the trunnion axis to the peg at the ground was measured as the height of the instrument.

· The instrument was oriented with reference to a fixed station which is already well defined.

· The reflector was held vertically as far as possible both for the case detail survey.

· Hard details were not missed as far as possible and were indicated by numbering in the reference map for the future reference of plotting.

After having distance and the direction obtained from the detail survey, details were plotted in the grid sheet while already contained the major and minor traverse stations.

2.5.6 CONTOURING

A contour is an imaginary line, which passes through the points of equal elevation. The surface of ground is intersected by a level surface in a line. A contour line is a line on the map representing a contour. It represents the elevation and is one of the ways of representing relief. While drawing the contour lines, the characteristics of the contours should be considered.

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 contour to be plotted is actually traced on the ground. Only those points are surveyed which happen to be plotted.

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. These guide points, having been plotted, serve as the basis for the interpolation of contours. There are some of the indirect methods of locating the ground points:

a. By squares

b.By cross-sections

c. By tachometric method

Contour Interpolation:

The process of drawing contours proportionately between the plotted ground points or in between the 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. It may be done by anyone of following methods:

* Estimation

* Arithmetic calculation

* Graphical method

The characteristics of contours are

i) Two contours of different elevations do not cross each other except in the case of an overhanging cliff.

ii) Contours of different elevations do not unite to form one contour except in the case of a vertical cliff.

iii) Contours drawn closer depict a steep slope and if drawn apart, represent a gentle slope.

iv) Contours equally spaced depict a uniform slope. When contours are parallel, equidistant and straight, these represent an inclined plane surface.

v) Contour at any point is perpendicular to the line of the steepest slope at the point.

vi) A contour line must close itself but need not be necessarily within the limits of the map itself.

vii) 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.

viii) When contours cross a ridge or V-shaped valley, they form sharp V-shapes across them. Contours represent a ridgeline, 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 towards the higher value contours.

ix) The same contour must appear on both the sides of a ridge or a valley.

x) Contours do not have sharp turnings.

Taking the reading at the change point on the ground is the indirect method of locating contours. The interpolation method is used to draw the contour lines. Interpolation of contours is done by estimation, by arithmetic calculations or by graphical method. The eye estimation method is extremely rough and is used for small-scale work only. Generally, arithmetic calculation method of interpolation is used to draw the contour line.

2.5.7 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 line may be defined as its coordinate lengths measured parallel to an assumed meridian direction. The latitude (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.

Relations,

Latitude = L*Cos q

Departure = L*Sinq

Where, L = distance of the traverse legs

q = Reduced 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 and error is known as closing error.

Mathematically,

Closing error (e) = Ö{(SL)² + (SD)²}

And

Direction, tanq = SD/SL

The sign of SL and SD will thus define the quadrant in which the closing error lies. The relative error of closure = error of Closure/ Perimeter of the traverse.

= e / p

= 1/ (p / e)

The error (e) in a closed traverse due to bearing may be determined by comparing the two bearings of the last line as observed at the first and last stations of traverse. If the closed traverse, has N number of sides then,

Correction for the first line = e/N

Correction for the second line = 2e/N

And similarly, correction for the last line = Ne/N = e

In a closed traverse, by geometry, the sum of the interior angles should be equal to (2n - 4) x 90⁰where n is the number of traverse sides. If the angles are measured with the same degree of precision, the error in the sum of the angles may be distributed equally among each angle of the traverse.

The Bowditch's method or the Transit rule is mostly used to balance a traverse where linear and angular measurements are of equal precision. The total error in latitude and in the departure is distributed in proportion to the lengths of the sides.

Mathematically,

a) Correction in departure of a side of traverse

= - (Total departure misclosure/traverse perimeter) x length of that side

b) Correction in latitude of a side of traverse

= - (Total latitude misclosure/traverse perimeter) x length of that side

In order to measure the lengths of the sides of the traverse, two ways taping (forward and backward) is done. In difficult areas where taping is not possible, other methods like Theodolite ranging is used. The difference in values obtained by forward and backward taping is called discrepancy. In addition, the reciprocal of the discrepancy divided by the mean of the two measurements is called precision. Both the discrepancy and the precision for each traverse leg should be within the given limits.

Mathematically,

Discrepancy = | Forward length - Backward length |

And Linear precision = 1/ (Mean length/Discrepancy)

The coordinates of traverse stations were calculated with respect to the given coordinate of the station “CP” and the bearing was transferred from the station to the major stations.

MINOR TRAVERSE

The method of forming traverse connected to the one or more station points of major traverse, which is run around the area to be detailed, is called Minor Traversing. All the vertical and horizontal controls are transferred from the major traverse stations. The minor traverse station points are so chosen that maximum details can be obtained at a point during plane tabling or tachometric surveying.

The following steps should be followed for minor traversing: -

· The minor traverse stations are fixed and marked by reconnaissance.

· Both forward and backward measurement of the traverse leg is done which should be within the limit 1:1000.

· For included angles, only one set of reading along with tachometric readings are taken.

· One set of horizontal reading was taken from each station.

· The angular closing error must be within L.C×Ön; where n = no. of stations.

2.6COMMENTS AND CONCLUSIONS

Hence the coordinates of the entire major as well as minor traverse stations were computed and were plotted in the grid sheet in suitable scale using Auto Cad Land Development software.

The given Topography survey camp work was finished satisfactorily within the given span of time. The subject survey needs practice as much as possible. For surveying, theory can only take as the introduction but if there is practice, there will be much gain of knowledge about the techniques of surveying. 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.

3. BRIDGE SITE SURVEY

INTRODUCTION

Bridge site survey includes the work to carry a survey for the construction of the bridge to join two banks of the river and allow continuation of the road and provide easy access for the people and the vehicle. Bridge construction is an important aspect which plays vital role in the development of the nation and its economy basically in the context of our country. Surveying is required for topographical mapping, while longitudinal section of the river and the cross-section of the upstream and downstream side of river are essential. Also the river flow level in the different sections as well as in different seasons should be taken into consideration before the design process of the bridge.

3.1 OBJECTIVES

The main objective of the bridge site survey is to obtain 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 is 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 level, high flood level, geological features of the ground, catchments areas for planning and designing of the bridge from the details taken from the surveying. Moreover bridge construction is an important aspect which plays major role in the development of transportation network. Thus, surveying is required for topographical mapping, knowledge of longitudinal sections of the river and cross-sections at both the upstream as well as in downstream side of the river of the construction of the bridge. The objectives of the bridge site survey can be summed as follows:

i. To find the average slope of the river and its catchments area.

To exercise the reciprocal leveling for RL transfer in bridge axis.
To perform triangulation method for measuring the bridge axis and detailing 100m upstream and 50 m downstream.
To prepare topographical map of the bridge site and hence prepare longitudinal and cross-section of the river at the required upstream and downstream of the river.
To accumulate the past information about the high flood level, normal flow level, river cut direction, river shifting pattern etc.

3.2 BRIEF DESCRIPTION OF THE AREA

Bridge site survey was conducted in one of the KAPAN BALUWA KHANI. This bridge site is surrounding with the steep hill and cultivable land. The bridge foundation or the bridge axis was selected such that the hard rock lies below it. The river was narrow with less meandering.

3.4 NORMS (TECHNICAL SPECIFICATION)

Establishment of control point forming well-conditioned triangle on bridge survey.

· Detailing of the area about 100m U/S and 50m D/S at every 25m interval and up to 15m on either cross side from bridge axis is taken.

· Traversing is done by triangulation.

· At least two base lines are measured by using tape (two way measurement).

· Sides are computed by using sine & cosine law.

· Distance and bearing from B.M. to nearest station (station A) was taken.

· Error in interior angles of the control point polygon is distributed equally in all stations since it lies within the permissible error (2N-4) * 90±ÖN*L.C. But in our case (2N-4)*90± 1’ÖN where N is the no of stations.

· Triangles were adjusted applying correction.

Plotting Scales

Topographic map: 1:500

L-section:

Horizontal: 1:1000

Vertical: 1:100

Cross-section:

Horizontal: 1:200

Vertical: 1:200

Contour interval: 1 m

3.5 EQUIPMENTS

The equipment used during bridge site survey are summed up as follows:

· Theodolite with tripod

· Staffs

· Ranging rods

· Auto level with tripod

· Measuring tape

· Compass with tripod

· Pegs

· Arrows

· Enamel paint or marker

3.6 METHODOLOGY

3.6.1 SITE SELECTION

This is the major or the vital aspect of the site selection of the proposed bridge site. There are various factors which directly or indirectly affects the site selection of the bridge. They are geological condition, socio-economic and ecological aspect etc. The foundation of the proposed bridge should be laid above very stable hard rocks at the bed of river as far as possible for the stability and long life of the bridge. The proposed bridge site should not affect or disturb the ecological balance of the flora and fauna of the locality in the site. The axis of the bridge should be laid such that the flow direction of the river at the same time the width of the river channel should be least from economical point of view. The free board must be taken 5m in least. The starting point of the axis of the bridge or the starting of the bridge itself should not lie or touch the curve portion of the road. In other words, it can be said that the axis of the bridge should not be followed by the curve while selecting the bridge.

For the purpose of having shorter span of the bridge, the stations were such selected that the river flow direction was made perpendicular to the flow direction of the river. There should not be cutting or banking of the river banks by the river water at the proposed bridge site.

3.6.2 TRIANGULATION

Triangulation is the process of forming number of connecting triangles so as to provide the control the points. Triangulation involves two processes, measurement of horizontal distances of any two side of the triangle formed on the opposite side of the frame between two control point by tape and the measurement of all the interior angles with the help of angle measuring instrument i.e. theodolite. All the remaining lengths of the side of the triangle is computed with the help of any one measured length and all the measured angle of the triangle formed. The axis length of the proposed bridge was computed as mentioned earlier using sine law of the triangle. The computed length of the bridge axis should not differ more than 5mm.

3.6.3 LONGITUDINAL SECTIONING

Profile levelling is the process of determining the elevations of the points at the short measured intervals along a fix line or alignment such as the center line of the railway, highway, canal or sewer. The fixed line may be a single straight line or it may be composed of a succession of straight lines or of a series of straight lines connected by curves. It is also known as longitudinal sectioning. By means of such sections the engineer is able to study the relationship between the existing ground surface and the levels of the proposed construction in the direction of its length. The profile is usually plotted on specially prepared profile paper, on which the vertical scale is much larger than the horizontal, of costs are made. Profile levelling, like differential levelling, requires the establishment of turning points on which both back and fore sights is taken. In addition, any number of intermediate sights may be taken on the points along the line from each set up of the instrument. It is generally best to set up the instrument to one side of the profile line to avoid too short sights on the points near the instrument. For each set up, intermediate sights should be taken after the fore sight on the next turning point has been taken. The position of the intermediate points on the profile is simultaneously located by chaining along the profile and noting their distances from the point of commencement.

For the longitudinal section of the river, the staff readings were taken at the interval of 25m. L – Section was carried out up to 50m downstream and 100m upstream. While taking observations on the staffs, it was held on the bed of the river. It must be checked whether the staff is above the stone or on the river bed. The chainage was measured along the river flow direction by spreading tape over the water. If possible short reaches of lengths must be taken while measuring chainage which prevents error on the linear measurement.

3.6.4 CROSS – SECTIONING

Cross- sections are run at right angles to the longitudinal profile and o the either side of it for the purpose of lateral outline of the ground surface. They provide the data for estimating quantities of earth work and for other purposes. The cross-sections are numbered consecutively from the commencement of the Centre line and are set out at right angles to the main line of section with the chain and tape. Cross-sections may be taken at each chain. The length of cross-section depends upon the nature of the work. The longitudinal and cross-sections may be worked together or separately as per the requirement

In the case of bridge survey, cross-sections are taken at every 15m interval. The spot heights were taken where the change of the slope of the ground was abrupt. Cross-sections must be taken at normal flood level, high flood level, and river banks etc. Theodolite was used for this purpose as tacheometer.

3.6.5 LEVELLING

§ Transferring R.L. from B.M. to control points

For the determination of the reduced level of all the control points fly leveling must be carried out to transfer reduced level of the nearest possible bench mark to all the control points. The R.L. of the bench mark was given to be 1570 m which was transferred to all the triangulation stations within given accuracy. For transferring the reduced level to opposite bank of the river Reciprocal Levelling was used.

Reciprocal Leveling:

Horizontal

113

Fig: Intersection

izontal Line

Horizontal Line

River

Rih_a

Level

Line of sight

Level Line

Lie

River

Horizontal Line

h_b

h_b׳

h_a׳

h_a׳

River

Horizontal Line

Horizontal Line

h_a

h_a

Level Line

Level Line

Y₁

Y₂

P₁

P₂

h_b

h_bCP

River

C14

When it is necessary to carry out leveling across a river, ravine or any obstacle requiring a long sight between two points so situated that no place for level can be found from which the lengths of foresight and back sight will be even approximately equal, special method, i.e. reciprocal leveling must be used to obtain accuracy and to eliminate the error in instrument adjustment, combined effect of earth’s curvature and the refraction of the atmosphere and the variation in the average refraction.

Fig : Reciprocal levelling

Let A and B be the points and observations be made with a level. For the first set up of instrument, three wire readings on both the staff held at the point A and B are observed and the level difference between them is calculated.

The level difference is calculated as:

Staff reading on A = h_a

Staff reading on B = h_b – e

Staff reading on A = h_a׳ - e

Staff reading on B = h_b׳

Taking average of two true difference of elevation, we get

2H= [h_a – (h_b – e) + (h_a׳ – e) - h_b׳]

= (h_a – h_b) + (h_a_׳- h_b́ )

H = 1/2[(h_a – h_b) + (h_a׳- h_b΄(

True difference of elevation is equal to mean of the two apparent differences in elevation.

3.6.6 DETAILING:

The detailing or detail survey was carried out with the help of Theodolite. The important or the hard details which were omitted or not taken in the longitudinal sectioning as well as in cross sectioning were taken. Trigonometric leveling was also performed in the case of determination of reduced level of inaccessible point. All the detailed points were noted for the topographical view of the bridge site.

3.6.7 COMPUTATION AND PLOTTING

In the case of triangulation, the horizontal and the vertical control of triangulation stations were determined and the horizontal as well as horizontal control of the other stations was manipulated later. The level or the elevation is calculated and usual checks were applied. Then plotting was done in appropriate scale.

Plotting Scale:

Topographic map: 1:500

3.7 COMMENTS AND CONCLUSION

In spite of the different kinds of obstacles in the field, the fieldwork as well as the final report was completed in time. In the field, there had some discussion on the route of the road and also in designing the curves, which led to good results, there was some problem. However, all the group members were very cautious and tried their best to get error free data and calculations. The road had to be designed on a pre-designed road, so group members felt the restrictions during the cutting and filling and also for the construction of different retaining structures.

4. ROAD ALIGNMENT SURVEY

INTRODUCTION

Transportation is important aspect of socio economic, cultural development of country and the locality since every commodity produced whether it is a food, clothing, and industrial products or medicine needs transport at all stages from production to distribution. Since Nepal is mountainous poor and landlocked country airway, railway, waterway, rope way are unable to fulfill the demand of transportation. So roadway is major part of transportation in Nepal. Among all modes road is the only mode which give maximum services to one and all. This mode has also the maximum flexibility for travel with reference to route, direction, time and speed of travel and provides door to door service. There is high road demand in Nepal at present context.

In this survey camp we studied about road transportation, its types and simple method of fixing road alignments.

Road classification

Roads in Nepal are classified as follows:

1. National Highways: National Highways are main roads connecting East to West and North to South of the Nation. These serve directly the greater portion of the longer distance travel, provide consistently higher level of service in terms of travel speeds, and bear the inter-community mobility. These roads shall be the main arterial routes passing through the length and breadth of the country as a whole. They are designated by letter “H” followed by a two-digit number.

2. Feeder Roads: Feeder roads are important roads of localized nature. These serve the community's wide interest and connect District Headquarters, Major economic centers, Tourism centers to National Highways or other feeder roads. They are designated by letter “F” followed by 3-digit number.

3. District Roads: District Roads are important roads within a district serving areas of production and markets, and connecting with each other or with the main highways.

4. Urban Roads: Urban Roads are the roads serving within the urban municipalities.

4.1 Brief description of project area

Road alignment was conducted in the budhanilkntha school

The road is start from one major station and end in another major station.

4.2 OBJECTIVES

Road Alignment Survey was done to accomplish the following objectives:

Ø To choose the best possible route for the road such that there were a minimum number of Intermediate Points (I.P.) thereby decreasing the number of turns on the road.

Ø To design smooth horizontal curves at points where the road changed its direction, in order to make the road comfortable for the passengers and the vehicles traveling on it.

Ø To design vertical alignment with appropriate gradient.

Ø To get preliminary idea of elements of roads like horizontal curve, hair pin bands, shoulder, camber, super elevation, right of way, setbacks, road drainage, cross drainage etc.

Ø To prepare L-section, X-section, plan view of roads showing their elements.

4.3 TECHNICAL SPECIFICATION

The technical specification of road construction and design are based on ‘Nepal Road Standard – 2070’ in Nepal. However we were bound to the norms given by survey instruction committee 2070. They are

1. Carry out reconnaissance survey and alignment selection of a road corridor (starting point will be IP₁ and the end point will be provided) more than 600m chainage.

2. Obligatory points, permissible gradient, bridge site, shape of valley, geometry of tentative horizontal and vertical curves etc. must be considered to select the best route. Always keep in mind SESE i.e. Short, Easy, Safe, Economical.

Design Norms/Standard

ü Permissible gradient : 1 to 12%

ü Radius of horizontal curve should not less than 12m.

ü Points of commence and point of tangency should not be located within the bridge axis.

ü Two successive curves should not be overlapped.

ü Deflection angle less than 3^o, setting out of horizontal curve is not necessary.

3. Bearing of starting leg is to be measured and bearing of next leg is calculated with respect to deflection angles.

4. Cross – sectional detail be in 15m interval (also in abrupt change point) and also in BC, MC, EC.

5. Carry out level along the road center line passing IPs with establishing TBMs at certain interval; close the loop, permissible error of closure must not be greater than ±25Ök mm.

6. Road formation width is 5.5 m (intermediate lane), volume of cut/fill should show in profile. Draw longitudinal profile of center lines of road in scale H = 1:1000 or 1:500 & V = 1:100 or 1:50 and cross – section in scale of h = V = 1:100 or 1:200.

7. Also soil type, climate and rainfall pattern must be noted.

8. Distance between IPs must be measured by total station. Accuracy required is 1:2000. Formation level must be shown in L – section and X – section.

4.5 EQUIPMENT’S USED

Total station
Reflector
Staffs
Level machine
Compass
Ranging rods
Tapes
Pegs
Enamel paint and marker

4.7 METHODOLOGY

4.7.1 RECONNAISSANCE

First of all preliminary inspection called reconnaissance was done by walking through the proposed road alignment from where the actual alignment of the road has to be run. The planning of works was made for the intersection points (IP) where the direction of the route has to be changed. After having complete reconnaissance the IP were fixed. For this the inter-visibility of the IP were kept in mind and was checked and the gradient or simply the slope between two IPs was made between 1 to 12 % according to NRS. At the same time, the peg with the IP no. was driven at the suitable position on the ground with references if needed. Establishment of all IPs in correct ways is completion of 50% of work.

4.7.2 MEASUREMENT OF LENGTH AND DEFLECTION ANGLES

The distances between the IPs were measured with the help of total station. Both forward as well as backward measurement of the distance was carried out. The accuracy for the linear measurement of the distance between IPs is 1:2000 as in the case of major traverse leg measurement.

One set of horizontal angle was measured for the deflection angle. The face left reading was observed and the deflection angles were calculated. As the traverse formed as open traverse, no angular correction could be made. So as far as possible, both the linear measurement as well as the angular measurements was observed carefully and precisely.

4.7.3 RL TRANSFER FROM BM TO IPS

To prepare the map of the given area, it was necessary to carry out the fly leveling from given BM to the IPs of the road alignment of the road.

· FS distance and BS distance must be in nearly equal distance so as to eliminate errors due to focusing, refraction and curvature. For maintaining equal distance, eye judgment and pacing is used.

· Three wire reading is taken. At each attempt mean value of three wires reading should not differ by 0.001m with the middle wire reading and was checked on the field.

· Fly leveling was run from BM to IPs and back to BM. For the correction we established two TBMs midway in the fly leveling.

· The RL of each staff station was found from rise and fall method.

· The permissible error was ±25Ök mm where K is the loop distance in km.

· Closing error within the permissible limit was distributed to all the staff stations according to their lengths (station to staff distance)

4.5.4 CURVE SETTING

Curves are generally used on highways and railways where it is necessary to change the direction of the motion of the vehicle. A curve may be circular, parabolic or spiral and is always tangential to the two straight directions commonly known as tangents. Curves which are generally used on highways are as follows:

· Simple Circular Curve

· Transition Curve

· Vertical curve

But we only design Simple Circular Curve in this alignment.

Simple Circular Curve

T₁

T₂

Fig: Simple Circular Curve

A simple circular curve is the one which consists of a single arc of a circle. It is tangential to both of the straight lines namely tangents. During the road survey, it is always kept in mind that the radius of the simple circular curve should not be less than 15m. As far as possible, flat circular curves are preferred to that of the sharp one. Flat curves are comfortable to the passengers and there is less possibility of accident. Before setting out the curve, its elements are essential to be computed. Some essential elements of simple circular curve are as follows:

Length of tangent: R tan (Δ/2)

Where,

R = radius of simple circular curve

Δ = deflection angle

Length of long chord: 2R Sin (Δ/2)
Apex distance: R (Sec(Δ/2) – 1)
Mid ordinate: R (1 - Cos(Δ/2))
Length of curve: ΠRΔ

180°

Chainage of T₁: Chainage of IP - R tan (Δ/2) …………….......BC
Chainage of D: Chainage of T₁ + length of curve/2 ………......MC
Chainage of T₂: Chainage of IP + length of curve …………….EC
Chainage of next IP: Chainage of T₂ + IP distance – previous tangent length.

4.5.5 LONGITUDINAL – SECTION

For the longitudinal section of the road, elevation at every 15m chainage was taken and also at the beginning, mid – point and end of curve points of the road alignment. If there is any specific change in between, it was also recorded.

Elements of L – section are:

· Ground level

· Formation level

· Gradient of formation level

· Volume of cut/fill

· Soil type

· Cross drainage

L – Section are plotted in graph with horizontal 1:1000 and vertical 1:100

4.7.6 CROSS – SECTION

Cross sections at different points are drawn perpendicular to the longitudinal section of the road on either side of its centerline in order to present the lateral outline of the ground. Cross sections are also equally useful in determining the amount of cut and fill required for the road construction. Cross sections were taken at 15 m intervals along the centerline of the road and details were taken as possible as up to 15m left and right also at points where there was a sharp change in the elevation. But it was not possible in all the places because of the boundaries and existing permanent structures and fenced land.

Elements of cross – section

· Ground level

· Formation level with road width

· Retaining walls and drainage

· Cambers provided

X – Section are plotted in graph with both vertical and horizontal 1:100

4.5.7 PLAN VIEW OF PROPOSED ROAD

The plan view of proposed road is the actual path of road designed.

Elements of plan view

· Horizontal curve

· Intersection points

· Cross drainage

· Any details

4.10 CONCLUSION

After the practice of this road alignment survey, we are able to design roads at difficult terrain taking factors like economy, convenience and its use into consideration. This survey gave us apt concept of different road design practice and made us confidence about practical design problems. We believe that such a work will be a lot of help for us in understanding the actual situation while undertaking actual design and construction work in the future.

CIVIL ENGINEERIGNG

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Friday, December 14, 2018

survey camp(theory) for civil engineering III/I

Reciprocal Leveling:

4. ROAD ALIGNMENT SURVEY

INTRODUCTION

4.1 Brief description of project area

4.2 OBJECTIVES

4.3 TECHNICAL SPECIFICATION

4.5 EQUIPMENT’S USED

4.7 METHODOLOGY

4.7.1 RECONNAISSANCE

4.7.2 MEASUREMENT OF LENGTH AND DEFLECTION ANGLES

4.7.3 RL TRANSFER FROM BM TO IPS

4.5.4 CURVE SETTING

4.7.6 CROSS – SECTION

4.5.7 PLAN VIEW OF PROPOSED ROAD

4.10 CONCLUSION

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