subject: surveying (17310) · subject: surveying (17310) topic 1. introduction contents •...

Third Semester

Second Year Civil Engineering

Sanjay Ghodawat Polytechnic, Atigre 1

Subject: Surveying (17310)

Topic 1. Introduction

Contents

• Definition of survey, Objects of different surveys, Uses of surveys. • Classification of

surveys- Primary and Secondary, Primary Division- Plane and Geodetic Surveys,

Secondary- Based on instruments used, Nature of field and Objective. Principles of

survey. • Conventional symbols in survey plans/maps.

Que.1 Define surveying.

Ans: Surveying- It is branch of civil engineering in which relative

positions of ground points are determined by taking linear and

angular measurement.

Que.2 State any two uses of survey.

Ans: Survey is useful for following:

1. To prepare a map or plan of the surveyed area for

attaching it to legal documents.

2. To plot control points of boundaries of locality

3. To determine relative heights or elevations of object.

4. To finalize and mark alignment i.e. center line of roadway,

railway or runway routes.

5. To decide suitable gradient and camber of road

depending on equal volume of cutting and filling.

Que.3 Write four uses of surveying.

Ans: Uses of surveying are: 1) Surveying is useful to plot ground details in various maps like

topographic and cadastral maps.

2) It is useful in navigational movement planning through military

survey.

3) Surveying is also useful in almost all civil projects i.e. road,

railway, dam, bridge and airport construction for longitudinal

and transverse details.

4) It is highly needed in land cover and land use analysis through

remote sensing techniques.

5) Surveying is a helping hand in tunnel excavation, underground

piping and mining works.

6) It is truly beneficial in collecting details of water bodies on

earth like lake, pond, river, sea etc.

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Que.4 Differentiate primary classification of surveying with respect

to extent of area and curvature of earth.

Plane Surveying Geodetic Surveying

1) The curvature of earth is not

taken into account

1) The curvature of earth is taken

into account

2) Covered Area is less than 250

Sq.Km

2) Covered Area is more than 250

Sq.Km.

Que.5 Differentiate between plane surveying and geodetic

surveying on any four points.

Plane surveying Geodetic surveying

1.The area covered is less than

260km2

1.The area covered is more than

260km2

2. The distance between two

ground points is straight.

2. The distance between two ground

points is curve.

3. Simple survey instruments are

useful like chain, compass, level

etc.

3. advance survey instruments are

necessary like theodolite, total

station, GIS,GPS etc.

4. Carried out by state Govt.

Agencies.

4.Carried out by central Govt. of

India in collaboration with GTS Dept.

5. Cartesion co-ordinate formulae

are useful.

5. Spherical trignometrical formulae

are useful.

6. Less accurate because no

correction is applied.

6. More accurate because

correction for curvature and

refraction is applied.

Que.6 Draw Conventional symbol for

i) Embankment ii) Pond or Lake

ii) Tunnel iv) Compound Wall

Embankment Pond or Lake Tunnel Compound Wall

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Que.7 Write the code of signals used in ranging with respect to :

i. Correct position ii. Fix the ranging rod

iii. Vertical position of ranging rod

iv. Move slowly to left of observer

Ans: Correct position : Both hands above Head and then Brought

Down

Fix the ranging rod : Both Arms extended forward

horizontally and the hands depressed briskly

Vertical position of ranging rod : 1 Right arm Up and moved

to the right.2. Left arm Up and moved to the Left

Move slowly to left of observer : Slow sweeps with Left Hand

Que.8 What are the objectives of following one each.

i) Topographic Survey ii)Cadastral Survey

iii) Engineering Survey iv)Mine Survey

Ans:

1) Topographic Survey : To determine natural features like

river, streams , lakes , hills etc and artificial features like

roads , railways , canal , town and villages .

2) Cadastral Survey : To fix property line , calculation of

land area , and to transfer of land property from one

owner to another.

3) Engineering Survey :To collect of required data for

planning , design and execution of engineering project

such as design of road , bridges, dams and transmission

line.

4) Mine Survey :To explore mineral deposits and to guide

tunneling and other operations associated with mining.

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Topic 2. Linear Measurements

Contents:

• Study and use of instruments for linear measurements- Metric chain Measuring Tapes

and its types, Ranging rod, Arrow, Peg, Digital tape, Methods of linear measurements-

By pacing, by speedometer, by chaining, by digital tape. • Ranging- Direct and

indirect ranging and procedure, Code of signals used in ranging • Chaining-

Procedure on plane and sloping ground. Correction of linear measurement for

incorrect length of chain/tape. (Simple problems)

Que.1 Define Ranging and Chaining.

Ans: Ranging : The operation of establishing intermediate points

on a straight line between two survey stations, when

distance between them is more than one chain length is

known as ranging.

Chaining : The process of measuring distance of a line with

the help of chain is called chaining.

Que.2 Defines the terms : i) Survey Station ii) Survey Line

iii)Offset iv)Triangulation

i) Survey Station : It is the point on ground from which

various observations are taken around

ii) Survey Line : It is the straight line joining two

successive survey stations is known as survey line.

iii) Offset : It is the lateral distance measured from the

survey line to the object in right or left side is called as

offset.

iv) Triangulation : The frame work consist of number of

connected well conditional triangle is called

Triangulation.

Que.3 Describe method of measuring distances on ground using

chain and arrows.

Ans: Method of measuring distances on ground.

1. Mark the position of survey stations whose distance is to

be measured using wooden peg. (say A and B)

2. now, ranging is done if distance is more than one chain

length(say C) to locate intermediate point.

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3. Unfold the chain by taking both handles in a hand and

throw it along line AB.

4. Remove peg and fix arrow at starting station A. fix arrow

in groove of handle tightly.

5. Now, give jerks to the chain to open connected ring and

links. Also, keep another arrow at far end of chain

6. Measure the distance using brass ring and brass Talley’s

provided at each 1m and 5m resp.

7. To measure further distance, chain is pulled longitudinally

and fixed the handle in groove.

8. Repeat the procedure till chain reaches at station B. Thus

total horizontal distance will be equal to addition of

distances measured of each parts.

Que.4 Explain in brief linear measurement using :

i) Pacing ii) Digital Tape

Pacing : This method is used only for knowing approximate

distance between the objects. In preliminary survey this

method can be used for linear measurement. This method

consists of counting the number of paces between the two

points of a line. The length of the line can then be

computed by knowing the average length of the pace. The

length of the pace varies with individuals, and also with the

nature of the ground and the speed of pacing.

Digital Tape : Digital tape measured features a top

mounted LCD screen i.e. display measurement digitally

allowing for user to easily read the measurement.It is easily

convert from metric to imperial with touch of button. Digital

tape is light in weight and compact and measures

accurate reading. The maximum measuring length of digital

tape is 4.8m.

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Que.5 Explain with sketch method of stepping of chaining on

sloping ground.

Ans: Procedure: To measure the horizontal distance between

points A & B on sloping ground following steps should be

followed ( Refer figure.)

1. Starting from point A, the chain is unfolded and

straightens by applying jerks up to maximum possible

distance (say P1) without any sag in it.

2. Now suspend the plumb bob from point P1 vertically to

touch the ground at point P2.

3. Measure the horizontal distance on straightened chain

using tally, ring and links as d(AP1).

4. Now repeat and follow the same steps at point P2 and

P4 to measure the horizontal distances d(P2P3) and

d(P4P5) to reach at point B.

5. Finally calculate total chained distance as d(AB) =

d(AP1) + d(P2P3) + d(P4P5)

Que.6 Write three types of obstacles in chaining with examples.

Ans: i. Obstacle which can be chained across but cannot be

ranged across. , Examples: Hill intervening, rising ground.

ii. Obstacle which can be ranged but cannot be chained

across., Example: River, pond etc.

iii. Obstacle which can be neither be ranged across not be

chained across, Example: Building obstruction

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Que.7 Draw sketches (two), how to overcome pond across the

chain line

Que.8 Describe the procedure of indirect ranging.

Ans: Procedure of indirect ranging.

1. If two stations i.e. A and B are not visible, then two

intermediate points M1 and N1 are selected such that both

stations will be intervisible from it.

2. Now, bisect the ranging rod at N1 from A and direct the

rodman to move in line of AN1 to get a new position as N2

3. Similarly, bisect the rod at M1 from B and move the rod at N

to N1 to N2

4. Again, by observing N2 and M2 from A and B respectively,

find the new position of intermediate points N3 and N4.

5. This should be continued till final points M and N are in line

with AB, thus, ranging is said to be completed.

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Que.9 Draw a neat labeled sketch of 30 metric surveying chain.

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Que.10 A 20m chain was found to be 6cm too long after chaining a

distance of 1059m. It was found to be 9cm too short after chaining

at the end 1985m. If the chain was correct before

commencement of work find the true distance.

a. Given : Line ABC, AB=1059m, AC=1985m

b. L= 20m, No error at start, 0.06m too long at B,

c. 0.09m too short

d. Find : True distance of AC = ?

Solution :

For part AB

L = Length of chain= 20 m

e = Average error in Chain = 0+0.06 /2 = 0.03m

L’ = Incorrect length of chain = L + e = 20 + 0.03 = 20.03

m

( since chain is too Long)

Measured Distance AB = 1059 m

True Distance = (L’/L) X Measured distance

True Distance AB = (20.03/20) X 1059 = 1060.59 m

Similarly,

For part BC

L = Length of chain= 20 m

e = Average error in Chain = 0.06+0.09 /2 = 0.075m

L’ = Incorrect length of chain = L+e = 20 - 0.075 = 19.925

m

( since chain is too Long)

Measured Distance BC = 1985 – 1059 = 926m

True Distance = (L’/L) X Measured distance

True Distance AB = (19.925/20) X 926 = 922.52 m

Total true distance of AC = True distance of (AB + BC)

= 1060.59 m + 922.52 m

= 1983.11 m

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Que.11 A 20 m chain was found to be 0.05m too long after chaining

800 m. it was found to be 0.10 m too long chaining 2000m. if the

chain was correct before commencement of work, find true

distance.

Ans: Standard length of chain= L = 20m, e1 = 0 m

Measured length of chain = ML = 800 m, e2 = 0.05m

Measured length of chain = ML = 1200 m, e3 = 0.10m

To find- True length

For 800 m distance

Incorrect length = 20+ (0+0.05)/2 = 20.025 m

TL1= L1/L X ML1

TL1 = 20.025/20 X 800

TL1= 801 m

Now, for 1200 m distance

Incorrect length = 20+ (0.05+0.10)/2 = 20.075 m

TL2= L1/L X ML1

TL2 = 20.075/20 X 1200

TL2 = 1204.5 m

TL= TL1 + TL2

TL= 801+1204.5

TL= 2005.5 m

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Topic 3. Chain Triangulation and cross staff survey.

Contents:

• Principles of chain survey-Triangulation, Survey station types and their selection,

survey line, Base line, Check line, Tie line. Offset, Types of offsets- Long, Short,

Perpendicular and oblique,

Instrument for setting offsets- Open cross staff, optical square, Principle of optical

square, Setting offset with open cross staff and optical square. Survey field book and

recording entries.

• Chain and Cross staff survey for finding area of the field. Simple numerical problems

Types of obstacles in chaining and methods of overcoming them. Simple numerical

problems.

Que.1 State four instruments used for setting offsets.

Ans: Instruments used for setting offsets:

1) Chain 2) Tape

3) Open & French Cross Staff 4) Circular & Indian Optical Square

Que.2 State principle of optical square.

Ans: Principle of optical square: The angle between the first incident

ray and the last reflected ray is twice to that of angle between

two mirrors in optical square.

Que.3 State and describe the types of offsets.

Ans:

1. Perpendicular offset- When the offset is taken at 900 to the

survey line, then it is known as perpendicular offset.

2. Oblique offset- When the offset is taken at an angle other

than 900(say 300 or 1200) to the survey line, then it is known

as Oblique offset.

3. Long offset- When the offset is taken at a distance more

than 15 m from the survey line, then it is known as Long

offset.

4. Short offset- When the offset is taken at a distance less than

15 m from the survey line, then it is known as Short offset.

5. Swing offset- when offset is set by swinging chain or tape to

survey line, such formed offset is called Swing offset.

Third Semester



Que.4 Draw sketch and write the procedure for setting offset to the left or

right side of survey line with open cross-staff.

Ans: Procedure for setting offset with open cross staff :

1. Keep the ranging rods at point P(fixed on survey line) and at

point A1 approximately.

2. The cross staff with stadia rod is fixed at point B.

3. Now two surveyors will observe both rods at A1 and P

simultaneously.

4. If both rods are not bisecting at a time, then rod at A1

should move towards right parallel to survey line (towards

left if rod is at A2) as shown in above fig.

5. Once both rods are bisected simultaneously then point A

can be fixed and perpendicular offset AB is said to be set to

given survey line PQ in left side.

Que.5 Draw a neat lebelled sketch of optical square. Explain its working.

Ans: Working of optical square-

1. Optical square works on principle of optical square to set

perpendicular offset

2. Keep ranging rods at point B and C as shown in fig.

3. Observe the both rods through eye vane of optical square ass

in figure 6(b) i.e. one direct image and other reflected image.

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4. Now, move the along survey line AB with looking through

optical square, till both rods coincided as in figure6(c)

5. Once, both rods matched each other point D can be marked

on ground and distance CD is measured as perpendicular offset.

Department of Civil Engineering

Sanjay Ghodawat Polytechnic, Atigre Page 1

For Details contact:

Mr. V.S. kumbhar

HOD

Civil Department,

Sanjay Ghodawat Polytechnic, Atigre.

Mob. No.: 7798306363

Ph. No.: 0230 -246312

Email ID: [email protected]

mailto:[email protected]

subject: surveying (17310) · subject: surveying (17310) topic 1. introduction contents •...

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