Basic Civil Engineering Lab Mannual

8/10/2019 Basic Civil Engineering Lab Mannual

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Government College of Engineering Karad, Dist. Satara

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GOVERNMENT COLLEGE OF ENGINEERING

KARAD, DIST

SATARA

2010 -2011

(AFF I LI ATED TO SH IVAJI UNI VERSITY KOLHAPUR)

BASIC CIVIL ENGINEERING

LABORATORYMANNUAL

CIVIL ENGINEERING DEPARTMENT


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GOVERNMENT COLLEGE OF ENGINEERING, KARAD

CIVIL ENGINEERING DEPARTMENT

Surveying Laboratory

Subject: Basic Civil Engineering

INDEX

Sr. No. Title Page No

1. Chaining, Ranging and offsetting 3

2 Prismatic Compass 9

3 Bearing And Included Angles 12

4 Study Of Dumpy Level 17

5 Collimation Plane Method 21

6 Rise And Fall Method 23

7 Planimeter 27

8 Digital Theodolite 33

9 Electronic 35

10 Layout And Setting Out Of Building 39

11 Sign Conventions 47

12 Site Visit 48


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EXPERIMENT NO.1

CHAINING, RANGING AND OFFSETTING.

Aim:To study the chaining, ranging and offsetting.

Instruments:Chain, tape, ranging rod cross staff, hammer etc.

Chain:

The chains are available in the lengths of 20 m. and 30 m. The chain

consists of 100 links for 20 m. chain. And 150 links for 30 m. chain. Link is

made of galvanized mild steel wire 4 mm in diameter. Length of each link is the

distance between the two centers of two consecutivemiddle rings. Each link isbent into loop at the ends and joined to each other by three small circular or oval

shaped rings. These rings offer flexibility to the chain. The ends of the chain are

provided with brass handle at each ends with a swivel joint, so that the chain

can be turned without twisting. A semicircular groove is provided in the center

on the outer periphery of handle for fixing the mild steel arrow. One arrow is

fixed at the end of each (one) chain length. Brass tags or tallies are inserted at

every 5 m. length to mark the part of chain. The length of chain is measured

from the outside of one handle to the outside of the other handle.

Classification of chains:

1) Merit chains: These are available in lengths of 20 m and 30 m.

2) Gunters chain or surveyorschain: It is 66 feet long and consists of 100

links.

3) Engineers chain: This chain is 33 feet long and consists of 16 links. It is

mainly used for measuring fields in cadastral survey.

Chaining:

Measurement of distance on ground with the help of chain is known as

Chaining. Chaining involves following operations:

1) Marketing the stations.

2) Unfolding the chain

3) Ranging

4)

Measurement of distance.


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5)

Folding the chain


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1) Marking the stations: The stations along the direction of survey line

aremarked with pegs.

2) Unfolding the chain:Two chainmen are required for measuring the

length of a line. The chainmen staying at the zero end of chain or starting

station is called follower, while the chainman going in forward direction

is known as leader. The leader carries few arrows and a ranging rod with

him. To unfold the chain, both the handles are kept in one hand and the

rest of the bundle of chain is thrown in the forward direction with the help

of other hand. Then the chain is laid straight.

3) Ranging: if the distance between two stations is less than one chain

length, then after stretching the chain the distance can directly be

measured, when the length of survey line is more than one chain length,

intermediate points are to be located in order that the chain is pilled along

the proper survey line in a straight direction. The fixing of intermediate

points on the survey line in between the station points is known as

ranging.

4) Measurement of distance: After intermediate points on the survey lines.

The straight-line distance is measured by stretching the chain between the

two points. The leader fixes up arrow at the end of one chain length,

touching the groove of handle. The chain is dragged forward up to the last

station point. The follower goes on collecting the arrows. The length of

the line is determined from the arrows collected by the follower. Each

arrow represents one chain length. Any fractional distance at the end is

measured by stretching the chain and counting the links up to the end

station. The total length of line is, thus, determined.

5) Folding the chain: Starting from the middle of the chain, it is folded,

holding pair of links at a time in zigzag manner.

RANGING:

It is the process of establishing some intermediate points on survey line,

between the two terminal stations, when the length of line exceeds the length of

chain. There are two methods of ranging.

a)

Direct ranging

b)

Indirect ranging


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a) Direct ranging:

Direct ranging is done when the ends of survey line are indivisible. It

can be done by eye or by an instrument called as line ranger.

1)

Ranging by eye:

After the chain is stretched and laid approximately on line AB, the follower

stands behind the ranging rod at A and the leader stands at such a distance not

greater than one chain length from A, with ranging rod to the desired direction

so that the ranging rod is brought in line with AB at point P

2)

Ranging By Line Ranger:

The line ranger consist of either two plane mirrors or two right angled

isosceles prisms, placed one above the other, as shown in figure. In case the

prisms are used, the diagonals of both prisms are silvered so as to reflect the

incident rays.

The line ranger is provided with a handle at the bottom, to hold the instrument

in hand. From the handle, required point can be transferred to the ground.

Two ranging rods are fixed at A and B. to obtain a point P on the

survey line AB, the surveyor holds the line ranger approximately very near to

the link line AB. Upper prism a b creceives rays from A which are reflected

by diagonal ab towards observer. The lower prism c d a receives rays from B

and these are reflected by diagonal cd to the observer. Thus, observer can see

both ranging rods held at A and B. The images of these two ranging rods

may not be coinciding indicating that the instrument is not on line AB. To

remove the parallax, the observer moves the instrument sideways till the two

images are in the same vertical line, as shown in figure. After this the poin t P

is transferred to the ground.

Thus use of line ranger proves to be advantageous from the point of view

of requirement of only one person to do the ranging. Line ranger can also beused for setting out right angles.


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b)Indirect Ranging or Reciprocal Ranging :

This process of ranging is adopted when both the ends of the survey line

are not indivisible either due to high intervening ground of due to long distance

between them. In such case ranging is done indirectly. Two intermediate pointM1 and N1 are selected on either side of ground in such a way that from M1

both N1 and B are visible and from N1 both M1 and A are visible. Two chain

mens stand with ranging rods is M1 and N1. Chainman at M1directs person at

N1 to move to N2 in line with M1 in line with N2 A. thus the two persons

continue to range each other alternating till both of them at M and N on line

AB. From M and N, other points can be established by direct ranging.

Offsets:

For locating the details on ground, with reference to survey lines, it is

necessary to measure lateral distance of the features on ground points from

survey lines. Such lateral distances which are measured from the chain line to

the objects are called as offsets, the offsets can be measured either to the right or

left of chain line.

The offsets are of two types

1)

Perpendicular offsets.2) Oblique or inclined offsets.

Perpendicular offsets are the lateral distances taken at right angles (900) to the

chain line. Oblique offsets are the lateral distances taken at an angle other than

900 to the chain line.

Generally metallic tape may be used for measuring offset distances for greater

accuracy, steel tape may be used.

Every offset is characterized by two measurements:

1) Chain age on chain line at which the offset is taken (Ap), and

2) Length of the offset (Pp), as shown in figure.

Offset Measurement:

1) Short and Long Offsets:

Offsets up to a distance of 15 m are called short offsets and those longer than

15 m are called as long offsets.2) Swing Offsets:


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A swing offset is the one which is obtained by swinging the tape from outside

point along a chain line. Short offset can be set out and measured by swinging

the tape along the chain line as shown in figure .the position of the offer on

chain line MN is located by swinging the tape from P and the point where they

are is tangential to the chain line, is the required foot of offset. In the figure, Pp

is the swing offset.

Instruments for setting out perpendicular offsets:

Offsets may be taken by using the instruments such as cross staff, optical

square. Indian optical square and prism square

1)

Cross Staff :

It is the simplest instruments used for setting out right angles. It consists of ahead in the form of wooden block or metallic frame with two pairs of vertical

slits and is mounted on a pole. These are of following types:

1) Open cross staff

2) French cross staff and

3) Adjustable cross staff

1) Open cross Staff: It is provided with two pairs of vertical slits. Each pair

of slits forms a line of sight at right angles to each other. The frame or hair is

mounted on a pole for perfect intersection.

2) French Cross Staff:

French cross staff consists of an octagonal box. Vertical sighting slits are cut in

the middle of each face, such that the lines between the ceriters of opposite slits

make an angle of 450 with each other. Thus with the help of French cross staff,

it is possible to set out angles of either 450 or 900.

3)

Adjustable cross staff:

It consists of two cylinders of equal diameter, one placed on top of the other.

Both the cylinders are provided with sighting slits. The upper cylinder carriers a

vernier and can be rotated relatively to lower cylinder. The lower cylinder is

graduated to degrees with suitable sub-divisions. Therefore it is possible to set

out any angle to the chain-line. Magnetic compass is provided at the top of

upper cylinder which measures bearings of the lines.

Out of above three types, the cross staff is commonly used to layperpendicular offset.


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Observations:

Sr.No.

Line Distance

Calculations:

Results:


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EXPERIMENT NO:2

PRISMATIC COMPASS

Aim:Study prismatic compass.

Instruments:-Prismatic compass, Tripod, plumb bob, rangingrods, pegs, crossStaffs, hammer etc.

Theory:

1. It consist of circular metal brass box about 100 mm diameter with a hard

steel pivot at the centre.

2. A magnetic needle is frcely suspended on the pivot and carries a graduated

aluminum ring. The graduations are marked from 00 to 3600 degrees in

clockwise direction; each degree is subdivided into two parts so that the

minimum reading of the scale is 30. The zero is placed at the south end and

1800at the north end and the graduations are marked in the inverted fashion.

The reason for inverted graduations is that when the reading is taken

through the reflecting prism, the graduations will be seen correct real

images.

3.

A reflecting prism carries a sighting slit and the object vane has a vertical

horse hair for bisection of the object. The object vane and the reflecting

prism are placed diametrically opposite to each other. The prism and the

object vane can be folded so as to lie on the glass cover of compass.

4.

The glass cover at the top of compass prevents the entry of dust inside the

compass.

5.

The object vane carries an adjustable mirror which can be slide on the

object vane. The object too high or too low can be sighted by reflection of

giving suitable inclination to this mirror.

6.

Hinged sun glasses usually red and blue are attached to the frame of prism.These colored glasses can be interposed into the line of sight when brighter

objects are to be sighted.

7. A brake pin is provided on the side of compass box to damp the oscillations

of the graduated circle with needle.

8.

When the compass is not in use, the object vane can be folded, presses

against the lifting pin, which lifts the needle from the pivot and holds it

against the lid. Thus undue wear of the pivot point is prevented.


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Procedure:

The prismatic compass is fixed on the top of a tripod by ball and socket

arrangement. The compass is required to be centered and leveled, over a station

point, before taking the bearings of lines. For this certain temporary adjustmentare to be carried out at each station, where the compass is set up over a station

point.

A)Temporary adjustments:

1)

Centering:

It is the operation in which the compass is to be set exactly over the station

point (peg). This is checked by dropping a small piece of stone or pebble from

the underside of the compass. If the stone falls on the top of peg, then centering


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is correct. Otherwise the legs of the tripod are adjusted in two positions at right

angles to each other.

2) Leveling:

The leveling is checked by keeping a circular pencil on the glass cover of the

compass. If the pencil does not roll, the compass is in level. Otherwise, it can be

done by ball and socket arrangement till the graduated ring moves freely inside

the compass box.

B)Observing the bearing of a line:

Suppose the bearing of a line OA is required to measure. The compass is

centered over station O as explained above the leveled as per above procedure.

Let the ranging rod be fixed at A turn the compass in the direction of lineOA. See through the eye vane and bisect the ranging rod at A, by the middle

hair of object vane. Let the needle i.e. graduated ring comes to rest. The

reflecting prism is adjusted to the eyesight of observer by raising or lowering

the stud. The reading under the vertical hair through prism is taken which gives

the bearing of line OA. The bearing obtained with the prismatic compass is

whole circle bearings (i.e. from 00to 360

0degree).

Result:


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EXPERIMENT NO. 3

BEARING AND INCLUDED ANGLES

Aim:To study the observation of bearings, measurement of included angles and

drawing the corrected polygon.

Theory:There are two type of compass 1) prismatic Compass 2) surveyors

compass. The nearing taken with prismatic compass are whole circle bearings

(00 to 3600) measurement in clockwise, and always with reference to north

direction. The bearing taken with surveyors compass are reduced or quadrantal

bearings (0

0

to 90

0

) measured in clockwise or anticlockwise, with reference tonorth or South Pole.

1.

Whole Circle bearing (W.C.B.)

2.

Quadrant bearing/Reducing bearing (Q.B./ R.B.)

1) Whole Circle Bearing (W.C.B.) :

In this system the bearing of the line is measured from the north pole with

reference to magnetic meridian towards the line in a clockwise direction only/

In figure the circle bearing of various lines are as follows:W.C.B. of line OA =30

0

W.C.B. of line OB = 1350

W.C.B. of lineOC= 2400

W.C.B. of line OD = 3000

The bearings measured with a prismatic compass are whole circle bearings.

2) Quadrant Bearing (Q.B.) system or Reduced Bearing:

In this system the bearing of a line is measured from north to south meridians

whichever is closer to a line in a clockwise or anticlockwise direction towards

east or west direction.

In figures quadrant bearings of various lines are as follows:

Q.B. of line OA= N 300E

Q.B. of line OB = S 450E

Q.B. of line OC = S600W

Q.B. of line OD = N 600W


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For this system the plane around the survey station is divided into four

quadrants North-South, East-West lines which are at right angles to each other.

Types of Bearings:Every line has two bearings. One is measured at starting point of the line

in forward direction and other is measured at the end point of the line in

backward direction. These two types of bearings of same line are:

1) Fore bearing (F.B.) of line.

2) Back Bearing (B.B.) of line.

1.

Fore bearings:It is defined as the bearing of the line observed in the forward direction of the

line. For a line AB, the forward direction is from A to B. so its bearing takenat

point A in the forward direction AB is its force bearing (F.B.) as shown in

figure. Similarly for line BA of figure the forward direction is from B towards

A and hence the bearing taken at point. B is fore bearing of line BA.

2. Back Bearing:

It is defined as the bearing of the line measured in the backward or opposite

direction of the line

For a line AB, the backward direction is from B towards A. So its bearings

taken at the end point B in the backward direction BA is its back is its back

bearing (B.B.). It is as shown in figure similarly for line BA, the back direction

is from A towards B and hence its back bearing is taken at irs end point A as

shown in figure:

Relation Between Fore Bearing and Back Bearing:

It is clear from the figure that the different between the fore bearing and

back bearing of a line is 1800 i.e. F.B.-B.B.=+/-1800

B.B.= F.B.+/-1800

If F.B.>1800 then, useve sign (B.B. = F.B.1800)

If F.B. < 1800 then, use +ve sign (B.B.) = F.B.1800)


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Calculation of included angles:

Included angle:If two straight lines meet at a point the two bearing / angles are produced.

The sum of these two angles is always 3600. The larger angle (> 1800) is called

exterior angle and smaller angle (


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If the F.B. and B.B. of the two intersecting lines are expressed in reduced or

Q.B form then bearing of the lines intersecting.

at point are converted into W.C.B. system and then calculations of included

angles are made as given above.Calculation of include angle in closed traverse:

Procedure of finding included angles:

Draw a rough sketch showing all F.B. s and B.B.sof all lines. Convert all

Q.B.s into W.C.B. s and show them on the sketch. At every intersecting point

one B.B. of previous line and one F.B. of next line are available. Subtract small

bearing from large bearing to get the included angle at that point.

At every intersecting point, one B.B. of previous line and one F.B. of next line

are available. When the calculated angle is greater than 1800 , it is exterior angle.

So subtract it form 3600 to get the correct included angle.

The proper value of included angle (exterior and interior angle) visible from the

sketch should be selected.

Check:

The sum of all included angle = (2n-4) x right angle

Where,

n = no. of sides of the traverse.

Figure shows closed traverse ABCDEFA of six sides (n = 6). All the bearing is

expressed in W.C.B. system.

Observations:

Sr. No. Line Fore bearing Back bearing difference

Result


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EXPERIMENT NO: 4

STUDY OF DUMPY LEVEL

Aim:To study the dumpy level, leveling staff.

Theory:

Dumpy level is commonly used for leveling work because it is compact

and stable type of instrument. The dumpy level consists of the following parts.

1. Leveling Head: to bring the bubble in the centre of its run.

2. The Limb: Body of the instrument to support the telescope.

3.

Level Tube: to make the line of sight horizontal.

4.

Tripod: to support the level.

As shown in figure the dumpy level has a telescope rigidly fixed to its supports

and a long bubble tube called main Bubble Tube attached at the top of the

telescope. The axis of the telescope is perpendicular to the vertical axis. The

telescope consists of objects glass, eyepiece and a diaphragm consisting of a

circular ring with cross wires. A ray shade is provided as a protection to objects

glass. The leveling head usually consists of two parallel plates with three foot

screws, leveling of the instrument can be done by means of these foot screws is

provided for small movement of the telescope. A cross bubble tube is also

provided for small movement of the telescope. A cross bubble tube is also

provided perpendicular to the main bubble tube. The telescope has a magnifying

power of about thirty diameters. In certain instruments, a compass is provided at

the bottom side of the telescope to observe the bearing of the lines. The

focusing screw is used to bring the image of the object into the plane of

crosshairs of the diaphragm. The eyepiece can be rotated in its socket to make

the crosshairs of the diaphragm distinct and clear. The dumpy level had the

following merits:

1)

It is stable and compact type of instrument.

2)

It is simple in construction with few movable parts.

3) The adjustments are not easily disturbed.


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The leveling staff:

The leveling staff is a device which enables the surveyors to measure the

vertical distance, by which the staff station i.e. the foot of the staff is above orbelow the horizontal line of sight. A leveling staff is a straight rectangular piece

of wood about 75 mm wide and 25mm thick. The foot of the staff represents

zero reading since graduations are marked from the foot of the staff upwards. A

self reading staff is one, the reading on which can be directly read by the

instrument man sighting through the telescope. Hence following types of self

reading staff are in common use:

Telescopic Staff (sop with pattern) :

The telephone staff may be made of seasoned timber or aluminum.

However the aluminum staffs are in common use now. It is usually 4 meter long

and made in three telescopic lengths. The top solid piece about 1.2 m long slides

into the central box of about 1.3 m length. The lower base of 1.5 m length

receives the central box.

The inner pieces can be pulled out one after another kept in position by

metal spring clamps at the back of each eyepiece. On the front face, decimeter

markings are neatly painted in black against a white background. The red dots

indicate completed meter marking. The least count of the staff is 5 mm. one

tenth of a meter is subdivided into twenty equal parts.

1) Folding Staff:

The staff is 4 meter long and consists of two 2 meter wooden pieces with hinged

joint in the centre. The width is 75 mm and thickness is about 18 mm. the

folding joint has a locking device at the back. When the two pieces are locked

together, the two pieces become rigid and straight. The foot of the staff is

protected by a brass cap at the bottom. To keep the staff vertical, a circular

bubble is fitted at the back. Each meter is subdivided into 200 divisions, the

thickness of the graduation being 5 mm. The meter numeral is painted in red

and the decimeter numeral is painted in black colour. The decimeter numerals

are marked continuously throughout the staff for the folding staff.


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Adjustments of the Dumpy Level

There are two types of adjustments

1) Temporary adjustments

2)

Permanent adjustment

Temporary adjustment:

These adjustments are carried out at each setup of the level, before taking

the readings on the staff. These are done in the following steps:

Setting up:

i) The tripod legs are properly spired on the ground and the dumpy level is

fixed to the tripod. If the tripod head is havinga circular bubbles, see that

it is in the centre.

ii) Leg adjustment: Bring all the foot screws to the centre of their run. Plant

any two legs firmly in the ground and move the third leg sideways or

radially till the main bubble and the cross bubble are approximately in the

center.

Leveling:

i)

Keep the telescope parallel to any pair foot screws and move the foot

screws either inwards or outwards direction till the bubble comes in the

centre.

ii) Rotate the telescope clockwise through 900 so that it lies over the third

foot screw. Turn this screw till the bubble comes in the centre.

iii)

Bring the level tube back to its original position without changing the

positions of the objective and eyepiece, check up the centering of the

bubble. Move the two foot screws inward or outward till the bubble

traverses in the centre.

iv) Turn the telescope clockwise through 900 and see whether the bubble

remains in the centre.

v)

If not repeat these operations till the bubble remains in the centre in both

the positions at right angles to each other.

vi) Now turn the telescope through 1800 and observe the bubble. If is does

not remain in the center, the instrument needs, to be corrected for its

permanent adjustments.


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Focusingthe eyepiece:

Hold a piece of white paper in front of the eyepiece and observe the

crosshairs. If the crosshairs are n ot clearly seen, move the eyepiece ring in

or out till the crosshairs are distinctly seen. While moving the eyepiece ring,see that the eyepiece does not come out from its socket.

Focusing the object glass:

Look through the eyepiece towards the staff and bring the image of the

staff in the plane of crosshairs by moving the focusing screw. Parallax is said

to be eliminated when there is no change in the staff reading when the eye is

moved up and down. After making the above adjustments, the instruments is

ready for taking observations i.e. the line of collimation is horizontal.

Permanent Adjustments:

The line of collimation, the axis of bubble tube and the vertical axis are

the fundamental axes of the dumpy level.

There is fixed relation between these fundamental lines or axes of the dumpy

level and it is as follows:

1.

The line of collimation should be parallel to the axis of bubble tube.

2.

The axis of the bubble tube should be perpendicular to the vertical axis.

Results:


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EXPEERIMENT NO: 5

REDUCATION OF LEVELS BY COLLIMATION PLANE METHOD

Aim:Reduction of levels by collimation plane method

Method Reduction of level:

These are two method of calculating the reduced levels or elevation of a point

from the staff readings observed in the field. (a) Collimation plane method (b)

rise and fall method.

Collimation plane method:

In this method, reduced level of collimation plane is found points (levels) are

found out with respect to the respective plane of the combination. The

procedure of finding reduced level is as given below.

a) First take back sight readings on benchmark and find R.L. of collimation

plane by adding back to R.L. of B.

R.L. of Collimation = R.L. of benchmark + backside reading

b)

Calculate the reduced level of intermediate point or change point from the

R.L. of collimation plane.

c)

After the instrument s shifted to new position, all the temporary adjustments

are carried out. Take a backside reading on a change point. Determine the

R.L. of new collimation plane.R.L. of new collimation plane = R.L. of

change point + B.S. reading

d)

Obtain the reduced level of the remaining points now from the R.L. of new

collimation plane.

e)

Repeat the procedure till leveling work is finished.

On completing the observations the arithmetical check is applied as

followed

Arithmetical check = B.S.F.S. = RL Last PointRL first point


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Observation Table:

Station

No.

B.S. I.S. F.S. H.I. R.L. Remark

Calculations:

Result:


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EXPEERIMENT NO: 6

REDUCATION OF LEVEL BY RISE AND FALL METHOD

Aim:Reeducation of level by rise and fall method

Rise and fall method:

In this method difference of elevation between two consecutive points is

determined by comparing each point after the first with that immediately

preceding it i.e. two consecutive staff reading. The R.L. of collimating plane is

not found out. The difference of reading will indicate rise or fall, depending

upon the staff reading at that point. The reduced level of each point is then

determined by the adding the rise or subtracting fall from reduced level of

proceeding point

Procedure:

In this method the reading of next point is compared with the reading of

the previous point whose reduced level is known. The difference between the

two readings is calculate. The previous reading minus next reading gives the

difference. If the previous reading is more than the next reading. The difference

is positive and then this difference is written in rise column because the next

point is located at higher position than the previous one. If the previous reading

is less than the next, then the difference is negative and written in fall column

because the next point is situated at lower position than the previous one.

Arithmetic Check:

Sum of all back sightssum of all fore sights = R.L. Last pointR.L. First point

Sum of all riseSum of all fall

i.e. B.S.F.S. = risefall = R.L. Last pointR.L.First point


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Comparison between collimation plane and rise and fall method

Collimation Plane Method Rise and Fall Method

1)

The method is less tedious and itinvolves less number of

calculations.

1)

This method is more tedious andinvolves more calculations.

2)

There is no check on the

reduction of levels of

intermediate points. Hence

mistake made in the calculation

of RLs of intermediate pointsremain undetected.

2)

There is complete check on the

reduction of levels of

intermediate points. Mistake

made in the calculation o

reduced levels of intermediatepoint will be carried forward.

3)

It is used for calculating reduced

levels of profile, leveling work

etc.

3)

This method is used for precise

leveling, fly leveling etc.

Observations:

Station No. B.S. I.S. F.S. Rise Fall F.L. Remark


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Check:B.S.F.S. = risefall = R.L. Last pointR.L.First point

Calculation:

Result:


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EXPEERIMENT NO: 7

MEASUREMENT OF AREA BY DIGITAL AND MACHANICAL PLANIMETER

(A)

Mechanical Planimeter

Aim:To measure the area of given figure.

Instruments:Planimeter, Drawing board, Drawing sheet etc.

Theory:

The planimeter consists of two arms hinged at the pivot point. One arm is called

as Anchor arm it has a fixed length. A needle point called as Anchor point is

provided to the Anchor arm and it is pricked on paper and held in position by

weight, which may be detachable or fixed. The other arm is the tracing arm and

it is of adjustable length. The tracing arm carries the tracing point which is

moved round the boundary of the figure whose area is to be measure. The

length of the tracing arm can be adjusted to the position shown on the chart

provided by the manufacturer in planimeter box. The totaldisplacement is

measured by a wheel. The wheel carries graduated drum which is divided into

100 parts. The vernier is provided by the side of drum to read tenths of a part of

the drum. There is a counting disc which has marking from 0 to 9 i.e. divided

into ten equal parts and is connected to the rolling wheel by means of gears. The

counting disc moves by one divided for every turn of the wheel and completes

one revolutions for every 10 turns of the drum. A fixed index near the disc is

used to know the number of times the zero of the disc has crossed he index

mark.

Working of the planimeter:

The planimeter rests on the anchor point, tracing point and the periphery of the

wheel. When the tracing point is moved round the boundary of the figure, the

wheel moves and some time slides whereas the anchor point remains fixed. The

normal components of the motion cause rotation of the wheel whereas the axial

components cause slip of the wheel without changing the reading on the dial.

The normal displacement is recorded by the rotation of the wheel and the area

of the figure can be measured.


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Reading of planimeter:

When the reading is to be taken first the figure on the counting dial or

disc is read. Then the reading on the drum or wheel is noted and finally

thevernier is read.Thus each reading will be of four digits. If for example thereading is taken as 2,576 then

i)

Figure 2 is red on counting disc.

ii) 57 is read on main scale of drum i.e. rolling wheel and

iii) Third digit 6 is read on the vernier scale which is near the main scale.

Setting of the tracing Arm:

Before the area of any figure is found our, first the setting of tracing arm

is to be done. Usually the manufacturing gives the position of vernier on tracer

bar corresponding to different scales in the form of a tabular chart. Hence

initially observing the scale of the figure whose area is to be set is found out

from the tabular chart pasted inside the box of the planimeter. Then the tracing

arm is correctly set to the reading by means of clamp and fine adjustment screw.

In certain planimeters, the marking such a 100 sq.cm. is engraved on the top of

tracing arm. This means that if the setting of tracing arm is done of this position

one unit on counting dial will be equal to 100 sq.cm.

Procedure to Find the area of the given figure plotted to scale:

Depending on the size of the figure, the anchor point can be placed either

outside the figure (if the figure is small) or inside the figure (if the figure is

large). If the figure is too large, the given plan i.e. figure can be subdivided into

suitable parts and the area of each part is measured separately and then the total

are of the given figure will be the summation of the areas of individual parts.

Procedure:

1)

Set the index mark on the tracing arm given figure according to the scale of

the plan and as per manufacturers instructions by using the clamp and slow

motion screw.


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2)

By pressing the anchor point on paper in a suitable position, it should be

endured that it is possible to move the tracing point round the boundary of

the figure without any obstruction.

3)

Then fix the anchor point firmly in the paper either inside or outside thefigure according as the figure is large or small.

4)

Make a mark on the boundary of the figure and set the tracing point on it.

5)

Take the initial reading (I.R.) as described earlier. It is not necessary to set

the initial reading to zero.

6) Move the tracing point steadily around the periphery of the figure always in

a clockwise direction till the starting point is reached.

7)

Note the number of times the zero of the counting disc passes the fixed index

mark in a clockwise or anticlockwise manner while the tracing point is

moved along the boundary of the figure.

8) Take the final reading of the dial (F.R.). The area of the figure is then

calculated by using the following formula:

Area of figure = M (F.R.I.R. +/- 10N + C

Where

(i)

M is the multiplying constant whose value is different for different

for different scales. M can be defined as the area corresponding to

one rotation of the wheel. The value of M is supplied by the

manufacturer in the tabular form along with the planimeter.

(ii)

F.R. and I.R. : Final an Initial readings.

(iii)

N = the number of times the zero of the counting disc passes the fixed

index mark in a clockwise or anticlockwise direction. Use (+) plus

sign when the zero passes the fixed index mark in clockwise direction

i.e. (6,7,8,9,0,1 etc.) and use (-) minus in when it passes in

anticlockwise directing i.e. (7,6,5,4,..etc.)

(iv)

C = It is a constant whose value is supplied for the manufacturer for

different scales. The value of C is to be added only when the anchor

point is inside the figure. The value of C is obviously zero, when

anchor point is outside the figure.


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Observations:

Sr.No. I.R. F.R. C M

Calculations: Area of Figure = M (F.R.I.R. +/- 10N +C

Results:


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B) Digital Planimeter

Electronic digital planimeters are used to find the area of irregular figures

quickly. The planimeter works on built in Nickel cadmium storage battery. Theseplanimeters consist of rotary encoder which has replaced the integrating wheel of old

mechanical planimeter. By an electronic circuit, the pulses of rotary encoder are

measured and area displayed in digital from.

Functional Keys-

On - Power supply on key

OFF - Power supply off key

C/AC - Clear and all clear key

START - It is a start key for starting measurement. When the key ispressed, buzzer sounds lightly.

HOLD -By pressed this key measured value (stored) held in the memory.

MEMO - It is a key for calculating average value.

UNIT-1 - It is key selecting unit within each unit system.

UNIT-2 - It is a shift key of the unit within each unit system.

SCALE - Pressing of this key causes the setting of the reduced scale.

R-S - Pressing of this key confirms the setting of reduced scale.

- Decimal point key.

O-9 - Numerical key.

Measurement Method:

Suppose area P shown In figure is to be measured.

1.

Preparation: paste or fix the drawing paper containing area on a drawing

board. Place the roller at the position which will make a right angle with

the main body. By tracing the outline of the figure if any inconvenient

movement of the roller is found, then position of the roller is adjusted.


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2. Precedure:

1.

Press On key to switch on paper key.2.

Select the unit using 2 keys of UNIT- 1 and UNIT- 2


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3.

Put a mark line A on the outer periphery of the figure to use it as a

starting point.

4.

Press START key the buzzer sounds lights confirm that display

shows O (Zero). Then trace the figure by lens (tracing point)clockwise round the circumference of the figure and close on starting

point. The area of figure will be displayed on display panel.

5.

Bigger areas are subdivided into two or three parts for convenience.

6.

By the use of MEMO and AVER keys, the same area can be

measured no. of times and its mean value can be obtained for

increased measuring accuracy.

Observations:

Result:


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Necessity of use of Electronic Distance Meter and Digital Theodolite

There are many applications where the distances are to be known continuously or at

regular intervals. It is only with the use of electronic Distance Meter that these can

be achieved at a very high speed and accuracy.

There are certain situations where the use of Electronic Distance Meter and

Digital Theodolite becomes a necessity. These are as listed below.

1. In a long bridge, the alignment of piers (intermediate supports) and thedistance between pier to pier is to be checked.

2.

In an industrial shed, the centre to center to center distance between columns

and the alignment of columns is to be checked.

3.

In an industrial shed, if the final product is obtained passing from one machine

to another and if the machines are installed in a straight line, the alignment of

machines as well as the perpendicularity of rollers is to be checked.

4. If the railway line is to be located on a curved track then the location of pointson the curve is to be done.

5.

If the verticality of is to be checked, the location of those points on curve are

to be done.

6. If the verticality of a TV tower is to be checked, the use of the electronic

distance meter becomes necessary.7.

There are some existing structure located and spread over large area then the

location of these structures and the co-ordinates of those structures withrespect to some origin could be obtained using Electronic Distance Meter.

8. Usually in a big project such as thermal Power station the sitting of different

units is done by drawing grid lines running North-South as well as East-West.

The location of the individual units of power station can be easily

accomplished using Digital Theodolite and Electronic Distance Meter

9.

The location of centers as well as the alignment of transmission towers

carrying over the head electric cables is easily done using the modern

electronic equipment.

10.

The measurement of area of developed machine parts is quickly done usingDigital Planimeter. Like this, there are number of other situations where the

use of modern electronic equipments becomes absolutely necessary to obtain

accuracy as well as to save time.


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EXPEERIMENT NO: 8

DIGITAL THEODOLITE

Aim:Study of digital theodolite and measurement of angles.

Instrument:Digital theodolite, Tripod, Ranging rods etc.

Theory:

Digital Theodolite:

These theodolite are the precise type of theodolite ( least count up to 1) in

which the horizontal angles or vertical angles are directly shown on the display panel

of the instrument. These require an external source of the power i.e. battery of

stipulated voltage while working with these instruments. A separate keyboard is

provided for the different operations of this theodolite. The angle measurements is

done by photoelectric increment rotary encoder which seems the motion of the

telescope and registers the numerical value of either horizontal or vertical angle in

degrees, minutes and seconds. The usual clamps and slow motion ( fine adjustment )

screws for the horizontal motion and vertical motion of the telescope are provided as

are provided in other types of theodolite.

The Essential or Main Parts of Digital Theodolite

1.

Thetelescope: It has eyepiece and diaphragm at one end and object at the other

end. The telescope is mounted on a spindle called as horizontal or trunnion

axis. The focusing ring or screw is provided with telescope for following of

the object.

2.

Clamp Screws.

3.

Horizontal Clamp:

This is used to arrest the motion of the telescope in the horizontal plane. The

slow motion of the telescope can be obtained by horizontal fine motion screw.

4.

Vertical Clamp:

This is used to stop the motion of the telescope in the vertical plane. The slow

motion of the telescope in vertical plane is obtained by using vertical fine

motion screw.


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5.

Leveling Head:

It consists of two parallel plates i.e. a tribrach and base plate. The tribrach

carries three leveling screws. The theodolite can be leveled by the leveling

screws. The theodolite can be fixed to a tripod head.

6.

Plate level:

Plate bubble is provided on the instrument and is kept parallel to horizontal

axis.

7. circular level:

It is provided on top of tribrach.

8.

Optical plummet :

It is a small telescope to see the centering of theodolite over the station point.

9.

Display window:

The display of horizontal angles and vertical angles is shown in the display

window.

Tripod:

It has adjustable legs. Theodolite is fixed on the tripod for set up of the

instrument.

Observations:

Result:


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EXPEERIMENT NO: 9

ELECTRONIC DISTANCE METER

Aim:Study of electronic Distance Meter.

Instruments:Electronic Distance Meter, Tripod.

Introduction:

Earlier we have seen the engineering works/ situations where accurate

measurement of distance becomes absolutely necessary. Similarly, direct

measurement of distance becomes very difficult when the terrain is very rough such

as valleys or steep hills. Electronic distance meter have developed which gives an

accuracy of 1 in 10 for range up to 50 km. these EDM works on external source of

power i.e. Ni- Cd battery of specified voltage.

Basic Principle:

Suppose the distance between A and B is to be measured. A wave is transited

from the transmitter station. A with certain phase angle. There is a reflected from B

and received back at the transmitter end at A with different phase angle. By

electronic circuitry at A the phase difference between the transmitted wave and

reflected wave is measured and converted into distance. The wave used for

measurement is called as measuring wave .

Principle of Phase Comparison:

Difference in phase between the transmitted and reflected waves represent the

fraction of wavelength by which the double length line exceeds an integral no. of

complete wavelength. Null method is used to measure the phase difference. For this

an electronic circuit called as decay line is interposed so as to delay the wave till

there is no phase difference between the emitted and received signals.

Classification of EDM Measurement:

a) Based on Range of Measurement-


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1. Short Range- up to 5 km which use infrared light wave as the signal.

2. Medium Range- up to 100 km. these instruments use micro waves.

3. Long Range- can measure distance greater than 100 km and use radio waves.

b) Based on the precision obtainable:

1. Less precise: Standard deviation of one measurement = + /- (5 mm + 5ppm)

2. Moderately precise: standard deviation of one

Measurement = +/- (5mm+ 1ppm)

3. Highly precise: instruments having a standard deviation of one

Measurement= + /- (1mm + 1ppm)

c)

Based on Degree of integration with theodolite : The electronic distance meter is

Usually coupled with precise theodolite (least count 1)

1. Telescope mounted instruments:

In this case, electronic distance meter is mounted on the telescope of thedoloite. The

line of sight of thedoloite and electronic distance meter though separate are parallelto each other.

2.

Electronic Tachometers:

The Electronic Distance Meter and Digital Theodolite have co-axial optics, i.e. line

of sight of each is combined into one. There is digital output of all measured data.

This is also called as total station.

Basic functions performed by EDM instruments:

1.

Generation of measuring and carrier wavesThe measuring waves generated in the frequency range of 7.5 MHz to 500 MHz

are not suitable for measuring the distance because when these waves travel

through atmosphere. There are susceptible to changes in temperature, pressure

refraction etc. called as atmospheric interference giving rise to fading and

scatter. Hence a carrier wave with a very high frequency is generated and is used

as a medium for transport of measuring wave.

2. Modulation and Demodulation of the Carrier wave:


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The process of electronically superimposing the measuring wave on the carrier

wave is called as modulation. This occur at the transmitter end, as the reflected

wave is received at the receiver end, the reverse of modulation i.e. demodulation

occurs in which the measuring wave is separated i.e. demodulation occurs in

which the measuring wave is separated from the carrier wave

3. Measurement of Phase difference:

The phase difference is measured and is converted into distance.

4.

Display of result:

The result of the measurement is displayed in the digital from. Usually

for land surveys and other constructional surveys, short range EDM

instruments are used in which infrared light waves are used. The infrared light

wave is transmitted in a manner similar to a visible light system ( having avelocity of propagation 299792.5km/s). the carrier wave source is a Gallium

Arsenide infrared emitting diode. These diodes can be easily amplitude,

modulated at the high frequency required for EDM instruments.

Cube Prisms:

These prisms are prepared from solid glass tubes which are cut along its diagonal,

the plan making an angle 45 with the faces of the cube. The characteristic of these

prism reflectors is that the incident wave and reflected wave travel along parallelpaths. This is obtainable over a 20 range of measurements of distance of electronic

distance meter increases with increase in number of prism.

Methods of Modulation:

1. Amplitude Modulation:This is used in short range instruments where light waves are the carrier waves. In

this method. The amplitude of the carrier wave is varied in direct proportion to the

amplitude of the carrier wave.

2. Frequency Modulation:

This is used in microwave instruments: wherein the frequency of the carrier wave is

varied in proportion to the frequency of the measuring wave. The ampliteude of

carrier wave remains constant. The measuring wave information is carried by

varying the frequency of the carrier wave.

Different makes of Electronic Distance Meter:

There are electronic distance meters manufactured by different companies such as:


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1.

SOKKIA Company, Tokyo Japan: the Red 2LV, Red 2A, and Red 2N are

brand names of EDM, which are mounted on precision theodolite or Digital

theodolite. Similarly, series B and series C total stations are in the market.

2.

Asahi, Precision Company Tokyo: Manufacturing Pentax Brand EMD, total

stations by brand name PTSIII 5C and 10C are in market.3. Leica Heerbrugg- AJ of Switzerland (previously known as wild. Switzerland)

manufacturing WILD T/TC 10110/1601 Electronic Distance Meters>

Observations:

Result:


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EXPERIMENT NO: 10

LAYOUT AND SETTING OUT OF BUILDINGS

Aim:To study layout of a building as per bye laws setting out of building.

Necessity:

Building bye laws are the restrictions laid down by the municipal. Town planning or

revenue authorities.

1.

To curve haphazard growth.2. To facilitate future use of land, widening of strict, to have hygienic environment

(to avoid pollution due to air, noise)

3. To ensure proper air, light, ventilation, parking, sanitation and safety of structure.

Definitions:

1) Covered area:

It is the ground area covered above plinth, but does not include compound wall,uncovered porches, and uncovered staircases.

2)

Plinth Area:

This is built up covered area measured at the floor level of the basement or of any

higher story whither is greater.

The following shall be included in the plinth area:-

a) Area of the walls at the floor level excluding plinth offsets, if any, when the

building consist of columns, projection beyond cladding.b) Internal shafts of sanitary installations provided these to do not not exceed 2.0

m in area. Air conditioning ducts, lifts.

3) Porches other cantilevers provided.

4) The area of barsati and the mumty at terrace level.

The following shall not be included in the terrace level.

1: Area of lofts.

2. Internal sanitary shafts provided these are more than 2.0 m in area.

3.

Unclosed balconies.


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4.

Unless they from a story at the terrace level, towers, turrests, domes

projecting above the terrace level.

5.

Architectural bands cornices etc.

6.

Vertical sun beakers or box louvers projecting out.

3) Floor area:

This is the usable covered area of the building at any floor level. To get floor area the

area of walls be deducted from the plinth area.

The following shall be included in the wall area.

1. Door and other opening in the wall.

2. Internal pillars and supports.

3. Plaster along walls exceeding 300cm in area.

4. Flues which are within the walls.

The following shall be excluded from the wall area.

1. Plaster along walls each not exceeding 300 cm in areas.

2. Fire place projecting beyond the face of wall in living or bedroom.

3. Chullah platforms projecting beyond the wall of kitchen.

4) Carpet Area:

This is the floor area of the usable rooms at any floor level.The carpet area of any

floor shall be the floor area worked as per floor area and exclude the following

portions of the building.

1.

Sanitary accommodations2. Verandahs

3. Corridors and passages

4. Kitchens and pantries

5. Stores in domestic buildings6.

Entrance hall and porches

7.

Staircases and mumties

8.

shaft for lifts

9. Barratries

10.

Garages11.

Canteens


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12.

Air conditioning ducts and air-conditioning plant rooms.

5) Floor area Ratio (FAR) or Floor Space Index (FSI)

Necessity:In town planning schemes, one of the most important factors to be controlled

is the density of population on a particular area of land. It is expressed as the

number of persons livening on a unit of land. Earlier, the method employed to

control the density was indirect, ie. By controlling the widths of open spaces

around building and their height in relation to the widths of roads or by limiting

the percentage of built up area to the plot area or by restricting the number of

floors that could be built on the plot. Also by restricting tenement density, the

control was achieved.

FAR or FSI is a new concept to regulate population density and to control

overcrowding in residential area.

Definition:

Total built up area on all floors

It is defined as FAR as FSI =

Plot area

Thus it is a ratio which indicates how much total area can be built with respect to

plot size. For preventing overcrowding in a particular region only, the maximum

permissible FSI is specified by local governing authorities.

FSI permitted varies depending on congested or non-congested regions. It also varies

with the purpose of the land use whether for residential or for commercial,educational, hospital use.

Let us assume that in a area, permissible FAR is 1.5 and plot area is 1000m it means

that total built up area should not be more than 1.5 X 1000 = 1500 m

Submission of Plans for Sanction:


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For obtaining sanction from the sanctioning authority, two sets of drawings

are required to be submitted( after obtaining initial sanction, detailed drawings are

drawn with a scale RF=1/50 or 2cm =1 meter)

Which should contain:-

1. Site planblock plan and area statement.2.

Ground floor plan, first floor plan, basement floor plan terrace plan, and car

park plan scale RF 1/100 i.e. 1mm =1m

3.

Elevation drawn to scale RF 1/100 i.e. 10mm = 1m

4. Sections passing through staircase W C bath, giving details of foundation>

5. Schedule of doors windows and girl work.6.

Schedule giving notes for type of construction, foundation work RCC work

etc.

Along with the plan the following documents are required to be submitted.

1.Notice to excite the proposed work in the standard from

2. Undertaking from the architect in the standard from.3.

Extract from property register stating the details regarding the owner and land.

4.

Plan from city survey office sowing boundaries of plot and a joining survey

numbers.

5. Certificate regarding area of the plot given by a corporation or town planning

Department.

BYE-LAWS REGARDING SET-BACK DISTANCE:

Set back distance:

It is the distance measured from the center line of road up to which plinth of

building may extend. This distance is fixed taking into account the future increase in

width of road possible disturbance that may cause due to noice, air pollution, space

required for parking of vehicles, free circulation of air etc. set back distance is more

in respect of cinemas, business centers, factories, etc. it is about 1.5 to 1.67 times the

distance required for residential buildings.


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Following Table givens the set back distances.

Type of road Minimum Set back distance for Ration of column 3 to column2

Residential Buildi Industrial Buildi

1 2 3 4

1. Village Road 9 15 1.67

2. Major District Road 15 24 1.60

3. National or state

Highway

30 45 1.5

BYE-LAWS REGARDING OPEN SPACE REQUIEMENTS:

It is essential to space around the building to meet requirements regarding.

1.

Lighting

2.

Ventilation

3.

Parking4. Future expansion.

5.

Good approach or access to other amenities.

Open space for front, rear and side yards depend upon the height of building and can

be calculated by using the following formula:

W= Width of open space around the building (in m)

=3+ (h-10) / 3)

Where

H= height of building in meters < 25m

Open space for rear yard for building of height less than 10m should be 3m average,

but in no case less than 1.8m.

Factors Influencing FSI / Built up Area:

While imposing restrictions on FSI / built up area, the following factors are taken

into considerations:


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1.

Location plot i.e. whether it is in Gaothan or Non-Gaothan area. Higher

FSI is permitted in Gaothan area similarly; Duo consideration is given to

factors like residential area, market area, and industrial area.

2.

Size of plot in general, higher FSI is permitted for smaller plots.

3.

Parking facilities: in public places like cinema halls adequate space isrequired for parking of vehicles. This indirectly influences built up area/FSI.

Maximum permissible built up area/ FSI are given in the following table:

Locality Area of plot Max. permissible FSI (%

A) Residential Area < 200 m

200-500 m

500-1000 m

>1000 m

2 storeyd structure

50%

40%

33 %

B) Industrial Area 60%

C) Market Area 75%

Minimum Requirements of Accommodation:

These limitations are laid down from view point of ventilation, hygienic

conditions and lighting and varying according to type of building, locality.

These are given in following table.

Description Minimum Requirement

1. Plinth Height2.

i) Height (from floor to ceiling)

ii) Mini. Clear head room under bea

3. Kitchen

4.

Kitchen cum dining

0.45 m

2.75 m

2.40 m


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5.

Bath room and water closet

i)

Bath room

ii) Water clost

iii) Combined bath room a&

closet.iv)

Height of bath room

6. Habitable room

i) Minimum width

ii)Floor area of residence

a)of single person

b)of more than one person

7. Light and Ventilation openings are

(excluding area of doors)

a)for hot climate region

b)for wet climate region

5.5 sq m with min width of 1.8 m

9.5 sq m with mini width of 2.4

1.8 m, [1.8 X 1.1]

1.1 m [1.1X 0.9]

2.8 m [2.0 m]

2.2

m

2.4 m

7.5 sq m

9.0 sq m

1 / 10

th

of floor area

1 /6th

of floor area

Limitations on Height of Building:

Maximum height of building depends upon

1.

Width of street on which building fronts.

2.

Minimum width of rear space.3. Vicinity of aerodromes.

Generally, it depends on the width of street and is as per the following table for

building in the vicinity of aerodromes, maximum height of building is decided in

consultation with civil aviation authorities.


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Width of street Max. Height of Building

1)

< 8 m

2)

8 to 12 m

3)

>12 m

1.5 times width of street

12 m < width of street

< 24 m

Result:


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EXPEERIMENT NO:11

SIGN CONVENTIONS

AIM:Study of conventional symbols.

While plotting the survey on paper, different features on the ground are shown by

different symbols. Some of conventional symbols recommended by ISI are as

shown in figure.

Result:


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EXPEERIMENT NO: 12

SITE VISIT

AIM:To visit a building,which is under contraction?

Type of Building:

Location:

Owner of the Building:

Visit Report:

Documents

Basic Civil Engineering Lab Mannual