bcee practical edited 22 august

8/13/2019 Bcee Practical Edited 22 August

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PRACTICAL NO.1.

STUDY & USE OF DUMPY LEVEL AND LEVELLING STAFF

AIM: To find reduced levels of various points using Dumpy level and levelling staff.

LEVELLING:

Levelling is defined as an operation of measuring relative heights or elevations of points

on or above the surface of the earth. It includes measurement in the vertical plane. The heights

are measured with respect to datum or arbitrary assumed level surface. The mean sea level is

generally referred as the datum all over the earth.

DUMPY LEVEL:

The dumpy level is used to provide a horizontal line of sight after the instrument is set up and

leveled. The dumpy level has following parts

1. Tripod stand:It is used to support dumpy level.2. Levelling head:It levels the dumpy level by bring bubble in the center of its run. It consists of

two parallel plates with three foot screws.

3. Telescope:The telescope is rigidly fixed to its supports and bubble tube is placed parallel toit. Telescope has movable eyepiece and objective on either side of it. A diaphragm with cross

hairs is placed before eyepiece. The focussing screw is provided for making image clear and

distinct. Ray shade may be provided to avoid direct entry of sun rays.

Dumpy Level


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AXES OF DUMPY LEVEL:

1. Line of collimation:It is the line joining center of diaphragm to the optical center of theobject glass and continues further to infinity. It is also called line of sight

2. Axis of telescope:It is line joining optical center of eyepiece and object glass.3. Axis of bubble tube:It is the imaginary line tangential to the longitudinal curvature of

the bubble tube at its center. It is also called bubble tube axis.

4. Vertical axis:It is the axis about which the telescope can be rotated in a horizontal plane.

Principal axis of Dumpy Level

Inter-relationship between various axes:

1. Line of collimation and axis of telescope are parallel and coincides with each other.2. Axis of telescope and line of collimation are parallel to bubble tube axis3. Vertical axis is perpendicular to the axis of telescope.TELESCOPIC LEVELLING STAFF:

It is made of aluminum and is usually of 4m in length. It consists of three parts which can

extend fully. The top solid piece of 1.2m long slides in central box of 1.3m length. The central

box further slides in lower box 0f 1.5m length. The readings on the self reading staff appeared to

be inverted and hence reading are taken from top to bottom. The staff has white background with

meter readings painted in red and decimeter reading painted in black. Its least count is 5mm. It is

mainly used for measuring the vertical distance by which the station is above or below the line of

sight


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TEMPORARY ADJUSTMENTS OF DUMPY LEVEL:

A) Setting up the level: this includes

1) Fixing the instrument on the tripod2) Leg adjustment: Bring all the foot screws of the level in the centre of their run .Fix any two

legs firmly into the ground by pressing them with hand and move the third leg to right or left

until the main bubble is roughly in the centre. Finally the legs are fixed after centeringapproximately both bubbles.

B) Levelling: -Levelling is done with the help of foot screws and bubble tube. The purpose of

levelling is to make the vertical axis truly vertical.

1) Place the telescope parallel to pair of foot screws.2) Hold these two foot screw between the thumb and first finger of each hand and turn them

uniformly so they are rotated either outward or inward simultaneously until the bubble is incentre.

3) Turn the telescope through 90so that it lies over the third foot screw.

4) Turn this foot screw only until the bubble is at center of its run.5) Bring the telescope back to its original position without reversing the eye piece and object

glass ends.

6) Again bring the bubble to the centre of its run and repeat these operations until the bubble

remains in the centre of its run in both position which are at right angle to each other.

7) Now rotate the instrument through 180, the bubble should remain in centre provided the

instrument is properly adjusted. If not, it needs permanent adjustment.


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C) Focussing the eye piece:To focus the eye piece, hold a white paper in front of the object

glass, and move the eye piece in or out till the cross hairs are distinctly seen.

D) Focussing the object glass:Direct the telescope to the leveling staff and on looking throughthe telescope, turn the focusing screw until the image appears clears and sharp.

IMPORTANT TERMS USED IN LEVELLING:Bench marks: Bench mark is a fixed reference point of known elevation with respect to some

datum.

Reduced Level (RL):It is the vertical distance of a point measured above or below the datum.

Backsight (BS):It is the first staff reading taken on a point of known elevation i.e. at benchmark

or change point after the level is set up and levelled.

Foresight (FS): It is the last reading observed before shifting the level i.e. before taking the

change point.

Intermediate sight (IS):All readings between back sight readings and foresight readings are the

intermediate sight (IS).

Height of instrument (HI): It is also called collimation plane level. HI is obtained by adding BS

reading to the RL of Bench mark.

Change point (CP): It is a point on which foresight and back sight readings are taken for the

further levelling work to be carried out and progressed.


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2. RISE AND FALL METHOD:

In this system, there is no need to determine R.L. of plane of collimation .The difference of level

between consecutive points are obtained as described below.

1. Prepare the format of level page before levelling work start.Staff

Station

B.S. I.S. F.S. Rise Fall R.L. Remark

B.M. B.M.

A

B

C

.

2. Determine the difference in staff readings between the consecutive points by comparingeach point after the first with that immediately proceeding it.

3. Obtained the rise or fall from the difference of their staff reading accordingly to the staffreading at the point is smaller or greater than that of proceeding point.

4. Find out the reduced level of each point by adding the rise to or subtracting fall from theR.L. of a proceeding point.

5. Arithmetic check: The difference between the sum of back sight and the sum of fore sight= difference between the sum of rise and the sum of fall = the difference between the lastR.L. and the first R.L.

B.S- F.S = RISE - FALL =LAST RL - FIRST RL


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PRACTICAL NO.2.

STUDY AND USES OF MAPS

AIM: To study any four types of maps and writing their uses.

MAPS:

It is defined as graphical representation of features on or near the surface of the earth in

small scale on a horizontal plane.

CHARACTERISTICS OF MAPS:

1. After surveying next step is to plot maps.2. Maps are used to show many features about portion of earths surface on paper so it can

be carried and transported easily.

3. Maps are not photographs of the earth surface.4. Maps are drawn with appropriate scale.

TOPOGRAPHIC MAPS:

It shows three dimensional world in two dimensions by using contour lines.

Engineers use for planning roads, buildings or other man made structures.

Trackers or mountaineers use topographic maps while mountain tracking.

Scale is 1cm = 2.5 km to 1cm = 0.25 km

LOCATION MAPS:

It shows boundary location of site with respect to nearby marks.

Scale used is 1:2500 to 1:500

CADASTRAL MAPS:

Cadastral is the French word which means extent, value and ownership of land for taxation

purpose.

Cadastral maps are used for:

1. Help government for legal transfer of land2. Keep record of land ownership3. Decide valuation and taxation of land

Scale used is 1:100, 1:2000, 1:5000 and 1:25000


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FOREST MAPS:

It shows record of national parks, sanctuaries, forest classes, boundaries and density of

vegetation. Satellite images are used to upgrade or renew information on maps. Scale used is

1:50000 to 1:2500000

GEOLOGICAL MAPS:

It shows different types of rocks that are below earths surface.

By studying these maps geologists can find the suitable location for the source of mineral

resources, oil and gravel deposits.

ENVIRONMENTAL MAPS:

These maps shows physiographic features like forests, grasslands, woodlands, ocean floors and

ocean sediments, grazing lands etc.

Meteorological maps are also the environmental maps which shows climate, weather and wind

changes.

Meteorologists, oceanographers, city planners use meteorological maps to record and forecast

their views about a particular area.

Example: meteorological map showing hourly maximum rainfall at various places.

BIOGEOGRAPHIC MAPS:

Scientists studying animals, plants and other living organism use maps to show where thesegroups live and migrate. Zoologists can study where organisms live and where they move.

Use to study migration of endangered species.

ROAD MAPS:

It shows road routes spread over the area,

It denotes highways and places connected by it. It also shows distances and also the highway

number.


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PRACTICAL NO.3.

DIGITAL PLANIMETER

AIM:Measurement of area of irregular figures by digital planimeter.

INTRODUCTION:

It is used for finding areas of irregular figures on sheet. The planimeters of conventional

type requires lots of time for setting of the tracing arm or scale. But digital planimeter has

reduced the time and area of figures can be determined very fast. The planimeter gets power

supply from AC or DC source.

CONSTRUCTION:

The digital planimeter has roller on one side and tracing arm on other side. The tracing arm

actually moves along the periphery of the figure whose area is to be measured.

Digital Planimeter

Function keys:

1. SCALE key: It indicate scale factor2. HOLD key: It can frozen the displayed reading3. MEMO key: The displayed figure is stored in memory4. END key: To display final answer after performing all operations5. BATT: It indicates low battery level6. E: It indicates the reading has exceeded more than eight digits.


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MEASUREMENT PROCEDURE:

1. Place sheet on horizontal plane. The planimeter is set with its roller and tracer arm atright angle to each other.

2. Press ON/ C key. The display shows 03. Select the scale by pressing or function key4. By pressing UNIT key select unit either cm2or m2or km25. Then trace the area. First mark the starting point on the outline of area. Place the point of

tracer arm on the start point. Press START key and see display is 0with a beep sound.

Move tracer arm clockwise along the line till it again come back to start point. At last

press HOLD key which will hold the final reading which is showing the area of figure in

terms of unit chosen.

OBSERVATION TABLE:

1.

Area of Regular Figure:

Sr. No. Description Area (cm )

1 Area of figure (Using Standard formula)

2 Area of figure (Using digital planimeter)

2. Area of Irregular Figure:Sr. No. Description Area (cm )

1

2

Average

Result:

Area of regular figure (Using digital planimeter) =

Area of Irregular figure (Using digital planimeter) =


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PRACTICAL NO.4.

ELECTRONIC DISTANCE METER (EDM)

AIM: Study basic principle and construction of Electronic distance meter.

INTRODUCTION:The direct measurement with tape is not possible when site is congested

or very undulating. In such case EDM is used. The least count of EDM is 1 mm. These are

highly accurate and quick in distance measurement. In EDM electromagnetic waves are

generated and transmitted and distance is measured indirectly using the characteristics of these

waves. These waves can travel even through vacuum.

NECESSITY OF ELECTRONIC DISTANCE METER

1. Alignment of transmission towers carrying electric cables2. Alignment of columns and center to center distance between columns of industrial

buildings

3. Contour maps for given piece of land4. Curves on the roads and railway tracks are located by EDM and digital theodolite.

DIFFERENT TYPES OF EDMs:

Telescope mounted instruments:The line of sight of theodolite and EDM are parallel to each

other

Total station:EDM and digital theodolite are built as one unit. The output is in digital form.

EDM base on range:The type of EDM is based on the range of measurement

1. Short range EDM: Range upto 5 km and uses infrared light as signal2. Medium range EDM: Range upto 100 km and uses microwaves3. Long range EDM: Range greater than 100 km and uses radio-waves.

Distomat: It uses infrared light waves to measure distance in the range of 20m to 10km. The

instrument can be used for day as well as night operation

Geodimeter:This instrument emits modulated pulses of light from a tungsten filament that are

reflected back by a reflector system having prisms at the other station. The reflected lightreturned to the instrument is converted into electric pulses by photocell and then comparison is

made between the transmitted and received signal. It can measure distance upto 25km.


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BASIC PRINCIPLE:

Let D be the distance between P & Q which is to be measured. A wave is transmitted

from the transmitter at station P with certain phase angle. There is reflector at other end Q which

consists of prism. The wave strikes on the reflector at Q and then gets reflected from Q. It is

received back at transmitter end P with different phase angle. For finding distance, phase anglebetween transmitted and reflected wave is measured and converted into distance.

Working Principle of EDM

PARTS OF EDM:

1. Levelling head: It makes line of collimation of LCD display horizontal.2. Control panel: For actual measurement of angles or distances.3. Horizontal clamp and tangent screw: To set at particular horizontal angle.4. Vertical clamp and tangent screw: It is operated for measuring inclined distances and

vertical angles.

5. Optical plummet: It is used for checking the centering of the instrument6. Aiming telescope: To sight the target station or prism.


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Electronic Distance Meter

ADVANTAGES:

1. Measurement of horizontal distance accurately.2. Measurement of vertical distances accurately.3.

Measurement in rough terrain

4. Measurement of north and east co-ordinates5. Measurement of inclined distances on slope

TYPES OF WAVES:

1. Electromagnetic waves: These are also called measuring waves. The waves in frequency range

500MHz to 705MHz are used for measuring distances. These waves cannot be transmitted

individually.

2. Carrier waves: Electromagnetic waves are superimposed on these waves. These waves have

very high frequency. The waves are superimposed by modulation process. For the reflectedwaves demodulation process is done where measuring wave and carrier waves are separated and

the phase difference of the measuring wave is determined and finally distance is measured.


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PRACTICAL NO.5.

VISIT TO CONSTRUCTION SITE

AIM:Visit to a construction site to study various construction materials used, type of structure,

type of foundation and components of superstructure.

A)STUDY OF CONSTRUCTION MATERIALS.CEMENT:

Cement is a binding material which gets hardened when mixed with water and attains strength.

Naturally cement is obtained by burning and then crushing natural cement stones which contains

argillaceous and calcareous materials.

Artificial cement obtained by burning appropriate proportioned argillaceous and calcareousmaterials at very high temperature and then grinding the resulting burnt mixture to a fine powder.

Cement is used in the form of cement mortar or cement concrete.

Types of cement: Ordinary Portland cement (most commonly used), Rapid hardening cement,

White or coloured cement, High Alumina cement, Pozzolona cement, Quick setting cement.

Uses of cement:

1. Construction of building: Ordinary Portland cement2.

Construction of Highway: Rapid hardening cement

3. Dams, retaining walls, bridges( mass concrete): Low heat cement4. Under water structures: Blast furnace slag cement5. Plastering work: White and coloured cement

Field Tests on Cements:

1. There should not be any visible lumps.2. The colour of cement should be normally greenish grey3. On heating, colour of cement should not change.4. Take a pinch of cement and feel between fingers it gives smooth feeling.5. Take a handful of cement and throw it on a bucket full of water, the particles should float

for some time before they sink.

6. If a regular block is made from thick paste of cement, keep in water for 2 hours. It shouldretain original shape and size.

This testing is used for small works


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BRICKS:

Bricks are obtained by moulding plastic mass of earth (clay) that contains silica and

alumina in timber or steel moulds. Moulded bricks are dried and then burnt in kilns to get

strength.

Bricks are rectangular with length two times the width. As per Indian Standards size is

19 cm 9 cm 9 cm with a suitable frog at top for proper locking of one layer with other.

Standard Brick or Conventional Brick

Clay bricks are divided as ordinary bricks and fir bricks

Ordinary bricks are further divided as 1stclass, 2

ndclass, 3

rdclass and zhama bricks

Requirements of Good bricks:

1. It should be sound hard well burnt uniform in size, shape and colour.2. It should not absorb water more than 20 % of its weight, when immersed in water for 24

hours.

3. The surface of brick should be such that no marks should appear when scratched.Uses of Bricks:

1. 1stclass & 2ndclass bricks used for construction of buildings, bridge piers, tunnel lining,and water structures.

2. 3rdclass bricks for compound wall3. Zhama bricks as road metal4. Fire bricks in acid plants, steel furnaces.

STONES:

The rock quarried from quarries is called stone.

Classification:

1. Geological classification: Igneous rock( basalt, granite), Sedimentary rocks (sandstone,limestone), metamorphic rocks( schist, marble)


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2. Physical classification: Stratified, Unstratified, laminated rocks.3. Chemical classification: Siliceous, Argillaceous, calcareous rocks.4. Based on rock hardness: Very hard, hard, medium, soft rock.

Requirements of good building stones:

1. It should have high strength, hardness, resistance to fire, weathering, decomposition andhave water resisting capacity, durability, impact value and toughness.

2. It should be less porous3. It should be free from cracks, joints and other defects.4. It should be easy to work with and able to take finish,5. Specific gravity should be between 2.3 to 2.5

Uses of stone:

1. Broken stones in foundation, road metal, railway ballast2. Quartzite for rubble masonry, road metal, aggregate3. Limestone for flooring4. Granite for kitchen platform5. Marble for ornamental and superior type of building.

SAND:

It is formed by decomposition of sandstones due to various weathering effects. It is a form of

silica.

It may be natural sand or artificial sand. Natural sand is formed by decomposition of stone due to

weathering effects. It is obtained from pits, shores, river beds and sea beds. Artificial sand is

obtained by crushing of stone. Sand is used in mortar and concrete.

As per Indian standards two types: sand passing through Sieve of 4.75 mm is fine sand and

retaining on sieve is coarse sand.

Uses:

1. Used in cement mortar for masonry, plastering work.2. Used in PCC, RCC

STEEL:

Alloy of iron and carbon, containing 0.25 to 1.25 % carbon.

Steel are elastic, ductile, malleable, forgeable, and weldable.

Mild steel used in from of I-section, Channel section, Angle, round bars as reinforcement in

concrete.


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Tor steel obtained from steel is mainly used as reinforcement in RCC.

Wires or tendons are used in prestressed concrete.

Standard Steel Sections

Uses:

1. Structural members: Trusses, beams2. Non structural members: Stairs, Windows, Doors3. Fabrication of steel pipes, tanks4. Corrugated sheets as roofing material5. Mild steel and tor steel used as reinforcement in RCC

CONCRETE:

Cement concrete is a building material obtained by mixing cement, fine aggregates

(sand), coarse aggregates and water in definite proportion.

Classification: Plain cement concrete (PCC), Reinforced cement concrete (RCC), Precastconcrete, Prestressed concrete.

Plain Cement Concrete: (PCC): It is obtained by mixing of cement, coarse aggregate, fine

aggregate and water. It has high compressive strength. It is used in construction of;

Name of construction Mix proportion of PCC

Levelling course below footing and mass

concreting work

1:4:8

Concrete flooring, compound walls, ordinary

machine base and pavement

1:3:6

Damp proof course at plinth 1:2:4

Reinforced Cement concrete: (RCC): To strengthen concrete against tensile stress, steel bars

as reinforcement bars embedded in concrete. This combination of steel and concrete is called

RCC. The reinforcement is generally in the form of mild steel and tor steel. RCC is used for

construction of multistoried building, marine structure, road, water tank, bridges.


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Cast in situ concrete: Concrete which is prepared and casted at site is called as cast in situ

concrete.

Precast concrete: A concrete which is prepared in factory and transported to the site is called

precast concrete.

Prestressed concrete: A concrete in which permanent internal stresses of known magnitude is

purposefully introduced to counteract desired degree of stresses caused in member in service.

B) SUBSTRUCTURETYPES OF FOUNDATION:

If depth of foundation (D) is less then width of foundation (B) then it is shallow foundation

otherwise it is deep foundation.

Types of Foundation

SHALLOW FOUNDATION:

SPREAD FOOTING:

They distribute load of superstructure over a wide area so that the soil bed can provide safe and

firm support

STRIP FOOTING: (Wall footing)

Used for light structures like garden walls. One or more number of steps is provided on either

side of the wall.


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ISOLATED FOOTING:

In framed structure the support individual columns. They have square, rectangular, circular or

sloped in shape.

Square Rectangular

Isolated column footing

COMBINED FOOTING:

If loads on two adjacent columns is very high or bearing capacity of the soil is relatively

less than the two columns are grouped together to form a combined footing.

If loads on both columns are same then provide rectangular combined footing or else provide a

trapezoidal footing.


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Rectangular Combined footing Trapezoidal Combined footing

C) SUPERSTRUCTURESuperstructure is the part lying above the ground level. It includes walls, roof, doors and

windows, flooring. Superstructure provides privacy and safety to the occupants.

1. Masonary units:Main function of wall is to enclose or divide space in building to make itmore useful. Wall provides privacy, afford security and give protection against wind, rain

and heat.

2. Flooring:These are horizontal structural members which divide building into differentlevel vertically. They provide support for occupant, furniture and equipment.

Components of flooring;

a) Base floor or subfloor: Structural component which impart strength and stability tosupport superimposed load.

b) Floor finishing: Provide hard smooth non absorbent surface to floor.3. Roofing:Roof is the uppermost part of the building. Main function is to provide covering

on the top of the building to protect from adverse effect of the weather.

4. Openings:Openings are to have natural light, ventilation and circulation of occupantson the floor.

a) Doors: It helps to move horizontally on floor of building. It consists of two parts.Door frame

Door shutter

Doors are made up of timber, steel or plastic. Door is located at the end of longer

wall for better privacy.


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b) Windows: Openings made in external walls of the building for the purpose ofproviding daylight, vision and ventilation. Windows consists of two parts

Window frame

Window shutter

Minimum area of window shall be 1/10

th

of floor area for residential building and1/15

thof the floor area for public building for better light and ventilation.

5. Ventilators: Openings provided above doors and windows to allow hot air to escapefrom room so that there is better circulation of air.


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bcee practical edited 22 august

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