unit - i basic civil and mech

8/2/2019 UNIT - I Basic Civil and Mech.

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Basic Civil and Mech. Engg.UNIT - I

SURVEYINGAND

CIVIL ENGINEERING MATERIALS


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Surveying Measurements

Why study surveying?

Example of a measurement science

Two quantities measured in surveying

Lengths Angles

All measurements are imperfect

Errors

Mistakes


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Measurement Errors

Sources of errors

Natural

Instrumental

Personal Types of errors

Systematic

Random

Terms used in describing errors Precision

Accuracy


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Uses and Importance of Surveying

Locate/ map resources

Engineering design Layout construction or

engineering projects Verify performance

Acquire reliable data

Provide control Usually for location


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Historical Development of Surveying

Early applications

Boundary location

Construction

Mapping Early surveys limited by technology

Crude and inconsistent methods

Development of sighting devices, standards,


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Historical Development of Surveying

Industrial revolution improved surveying

Advances in available materials

Improvement in tools

Electronics revolution fundamental advances Electronic distance and angle measurement

Satellite surveying

Enhanced processing

Modern surveying Rapidly developing and evolving


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SURVEYING

SURVEYING - process of measuringa) horizontal / vertical distances and

b) included angle

in order to determine

location of points on, above or below the earth surface.

direct / indirect

Representation of surface features in a horizontal plane

LEVELLINGProcess of determining relative heights in thevertical plane

General meaningTo inspect, view, scrutinize, or examineTo determine condition, situation, or value


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PURPOSE ( Surveying)

Data - to prepare plan or map, showing ground features

To determine relative heights of objects/ points in avertical plane

To fix control points hence establish boundaries

Uses: Setting of building, roads, rail track, dam..etc

TYPES - SURVEYING

Plane Surveying Geodetic Surveying


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Nature of field of survey:i) Land Surveying

ii) Astronomical Surveyingiii) Marine / Hydrographic surveying

Discipline of surveyi) Engg. Survey

ii) Geological Surveyiii) Mine Surveyiv) Military Surveyv) Archaeological Survey

Instrument usedi) Chain Surveyingii) Compass iii) Plane table iv) Levelv) Theodolite vi) photographic surveying

CLASSIFICATION:


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Control surveying : To establish horizontal and vertical positions of control points. Land surveying : To determine the boundaries and areas of parcels of land, also

known as property survey, boundary survey or cadastral survey. Topographic survey : To prepare a plan/ map of a region which includes natural as

well as and man-made features including elevation. Engineering survey : To collect requisite data for planning, design and execution of

engineering projects. Three broad steps are1) Reconnaissance survey : To explore site conditions and availability of

infrastructures.2) Preliminary survey : To collect adequate data to prepare plan /map of area

to be used for planning and design.3) Location survey : To set out work on the ground for actual construction /

execution of the project. Route survey : To plan, design, and laying out of route such as highways, railways,

canals, pipelines, and other linear projects. Construction surveys : Surveys which are required for establishment of points, lines,

grades, and for staking out engineering works (after the plans have been preparedand the structural design has been done).

Astronomic surveys : To determine the latitude, longitude (of the observation station)and azimuth (of a line through observation station) from astronomical observation.

Mine surveys : To carry out surveying specific for opencast and underground miningpurposes.
http://nptel.iitm.ac.in/courses/Webcourse-contents/IIT-ROORKEE/SURVEYING/modules/module1/htmlpage/8.htmhttp://nptel.iitm.ac.in/courses/Webcourse-contents/IIT-ROORKEE/SURVEYING/modules/module1/htmlpage/8.htmhttp://nptel.iitm.ac.in/courses/Webcourse-contents/IIT-ROORKEE/SURVEYING/modules/module1/htmlpage/8.htmhttp://nptel.iitm.ac.in/courses/Webcourse-contents/IIT-ROORKEE/SURVEYING/modules/module1/htmlpage/8.htm


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PRINCIPLE I

Any surveying work should be carried out from whole topart

PRINCIPLE II New points should be fixed by atleasttwo independentmeasurements

i) measurement of 2 distances

ii) 2 anglesiii) 1 angle and 1 distance

Principle of Surveying

http://nptel.iitm.ac.in/courses/Webcourse-contents/IIT-ROORKEE/SURVEYING/modules/module1/htmlpage/9(1).htm

Reference:


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Surveying by the Germansduring the First World War, 1918
http://en.wikipedia.org/wiki/First_World_Warhttp://en.wikipedia.org/wiki/1918http://en.wikipedia.org/wiki/1918http://en.wikipedia.org/wiki/First_World_War


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OLDEST METHOD OF SURVEYING

HORIZONTAL MEASUREMENTPRINCIPLE OF TRIANGULATION

USED FOR MEASURING SMALL AREAS OF LAND WHEN THE

LEVEL OF ACCURACY REQUIRED IS NOT HIGH

Only linear distances on field measured

These distance are used to define boundary of field andmark simple details

Principle: Form network of triangles by using distancesmeasured (For better accuracy equilateral )

Accessories:a) Meter Chain b) Chain pins (arrows)

c) measuring tape d) Ranging / offset rod

CHAIN SURVEYING

1) MEASUREMENT OF DISTANCES


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For field surveying

To measure distance btwn 2 points on ground

Available in lengths of 5m, 10m, 20m & 30m

Specification IS: 1492 1970 (Reaffirmed 1978)

Surveying chain

Brass handles with brass eyebolt and collar,

Galvanized mild steel links and

wire rings

LENGTH OF CHAIN:

Distance - Outside faces - fully stretched chain

Engraved on handles

Grooves cut on outside face of handles for holding arrows in position

METRIC SURVEYING CHAIN


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Lincoln with Surveyor's Chain

CHAIN SURVEYING - ACCESSORIES

Metric Surveying Chain

Brasshandle

GalvanisedMS links

Brasstallies

Flexiblejoint


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Chain Pins (Arrows)

Made of good qualityhardened & tempered steelwire of min. tensile strength70kg/mm2

Overall length = 400 mm

Thickness = 4 mm

Wire Black enamelled

Wooden Pegs- Used to establish station pointsor end points of a line on the ground

- Driven by wooden hammer

Circular eye


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Measuring tape

i) Cloth / linen tapeii) Metallic tape 1 m = 100 divisions (cm)iii) Steel tape - cm, further subdivided

iv) Invar tape

Reinforced with fine brass, copper/ bronze wires Available in lengths of 10, 15, 20, 30 & 50 m


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RANGING ROD

Ranging Pole / Picket used for ranging / aligning long lines on ground in field surveying Ranging a straight line means fixing a series of pegs,

so that they all lie on a straight line Ranging rods are used for marking points on ground,

so that the positions of points are distinctly visible from some distance. made of well seasoned, straight grained timber of circular C/ S

(teak, blue pine, sissoo or deodar)

RED & WHITE orBLACK & WHITE (200 mm bands)

Dia.= 30mm

RED BAND

WHITE BAND

Cast Iron / Steel Sheet Shoe


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Is also a ranging rod with two short, narrow, vertical sighting slotsthru the center

Hook or groove top to enable pulling/ pushing the chain thruobstructions like hedges.

Offset rods are meant for setting out lines approx. at right angles tomain line.

(Diagram)

OFFSET ROD


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PLUMB BOB(used on sloping ground)

Illustration showing how to use a Cross Staff,

a surveying instrument with sights at right angles

Used to set out right angles in chain surveying

Consists of solid conicalpiece, with a string attachedto it at center

Used: to test verticality ofranging rods and

To transfer the points to theground


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OUTLINE OF CHAIN SURVEYING:

1) Base line is fixed and aligned by ranging2) Length of line measured (chain) Follower holds zero end of

chain, Leader drags chain to intermediate point on the line.Leader marks end of chain by chain pin. Follower holds the zeroend at chain pinFor locating the details, lateral measurements are taken to the

objects. These lateral measurements are called OFFSETS.a) Perpendicular offset b) Oblique offset

(Diagram)

Ranging a line:

means fixing a series of pegs such that they all lie on a straight line

(Diagram)

Unfolding and folding a chain


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Chain Survey of a Area

Mark corners of the Area to be surveyed Take Bearing from first corner (A) to second (B)

Measure A-B distance using Chain or Tape

Optionally, take Offset Readings en route of:

Objects Crossed & Nearby Objects and their Distance & Bearing (may be estimated)

At Point B - take a Back Bearing to Point A

if 2 or 3 deg off, use average the two readings

if > 3 deg off, then redo initial reading

Continue each subsequent leg in this way


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Advantages / Suitability of Chain Surveying1) simple

2) Doesnt require costly equipment3) Adopted for preparing small areas4) It can be adopted when ground is fairly level.

Limitations / Unsuitability of chain surveying :1) cannot be used for large areas

2) cannot be used in areas with a number of details

3) Cannot be used in thick bushy / (up and down) areas

4) Not always accurate

O OG S C S G


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1. Main Survey Station:Point where two sides of a main triangle meet

2. Tie stations / Subsidiary stations:

These are stations selected on main survey lines for running auxiliary lines.

3. Base Line:Longest of the main survey lines- is the main reference line for fixing the positions of various stations and

also to fix the directions of other lines

Caution: Accuracy of the entire triangulation critically depends on thismeasurement hence measure carefully

4. Check Line:used in the field to check the accuracy of the measurements made

5. Tie Line:Chain line joining the tie stations and subsidiary stations

6. Offset:While survey is carried out, important details such as boundaries, fences,

buildings and towers are located with respect to main chain lines by means oflateral measurements. The two types of representing (called OFFSETS)

a) Perpendicular offset b) Oblique offset

TERMINOLOGIES CHAIN SURVEYING


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90

A

C

B

x

x

A B

PERPENDICULAR OFFSET

OBLIQUE OFFSET

Layout of Chain Survey (dia. book)

TRAVERSE SURVEY

POND

A B

C

DE

F

1) Closed Traverse 2) Open Traverse

A

B

C

D

E


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2) Measurement of ANGLES

12

Included angles

Deflection angles

1

2


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COMPASS SURVEYING

Lincoln with Surveyor's Compass

- To measure angles

- Used when no. of base lines are to be run for obtaining details


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For Rough surveyingspeed is important, rather thanaccuracy

Used for preliminary survey for road, railway, militarypurpose, rough traverse, etc.

LIMITATION: The results from compass observationmay be unrealistic in places where there is more localattraction* due to magnetic rock or iron ore deposits.

PRISMATIC COMPASS

* External magnetic influences (magnetic rock, steel structure, railways, iron lamp posts)present in the place of observation

Needle will be deflected TO DETECT PRESENCE: 1) Find FB and BB of a line 2) Find FB BB

3) If FB BB 180


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PRISMATIC COMPASS

Prismatic Compass on a Tripod

Top View of Compass


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SURVEYORS COMPASS

Used with a chain when traversing Provides a relatively quick method of measuring horizontal directions in surveying

The surveyor's compass is usually the larger and more accurate instrument generally used on a stand or tripod. The prismatic compass is often a small instrument which is held in the hand

for observing, and is therefore employed for less accurate work.


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COMPARISON

PRISMATIC COMPASS SURVEYORs COMPASS

1) Magnetic Needle and

graduated dial attached together Prism and box rotate

1) Magnetic needle remains

freely suspended, stationerywhile dial is attached to box

2) Graduations markedCLOCKWISE

2) Graduations marked 0 -90 in all 4 quadrants

3) Readings observed thru

PRISM eyepiece from SOUTHEND of compass

3) Readings taken by directly

looking at dial immediately belowNORTH END of needle.

4) ZERO reading is marked onSOUTH END of instrument

4) ZERO reading marked onNORTH & SOUTH END.

5) Mirror attached to objectvane for sighting objects athigher elevation or depression

5) No such mirror

6) Can be held in hand whiletaking observations

6) Needs a TRIPOD

BEARING


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Bearing is the horizontal angle between the reference meridian and survey line

1) TRUE BEARING:

* True bearing of a line is the angle which a line makes with the true

north /geographicalnorth

* measured always in CLOCKWISE direction

* range of measurement: 0 - 360

2) MAGNETIC BEARING:

* angle a line makes with magnetic north

* measured in CLOCKWISE direction

* range of measurement: 0 - 360

3) WHOLE CIRCLE BEARING (W.C.B)

* any angle measured in between 0 - 360 directly

* The magnetic and true bearing are just whole circle bearings.

4) REDUCED BEARING (R.B) / QUADRANTAL BEARING

* Based on Quadrantal system

* wherein any angle is measured with respect to North South line,towards East or West

(Refer Dia.)

BEARING


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5) FORE BEARING (F.B):* Angle measured from a survey station to another station* in the direction in which survey is conducted

6) BACK BEARING (B.B):* Bearing taken from next station to its preceding station, from

which the fore bearing was taken.

RULES FOR CONVERSION OF W.C.B R.B

1) WCB = 0 - 360 ; RB : (0 - 90, Quadrant) eg. N 2030 E2) O for WCB starts from NORTH, CLOCKWISE.3) Always take RB with respect to NORTH - SOUTH line4) In RB, to convert FB BB or vice versa,

Replace N S, SN, EW, W E, (without changing the

numerical values)

RULE for converting BB to FB: BB = FB 180 { +ve if FB < 180,- ve if FB > 180}


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TRAVERSING WITH COMPASS AND CHAIN

In Compass Surveying, instrument is set at each stationsuccessively

FB and BB of each line are noted in a field note book

Errors in this survey tend to compensate as each bearing isobserved independently

Distance between successive stations are measured using a chain

Offset points are located by chaining OR by angular measurementswith compass.

LEVELLING


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Art of determining relative heights of points (vertical plane) on theearths surface

OBJECTIVES:1) Levelling provides accurate network of heights, covering the

entire area of the project

2) A good network of levels provides excellent idea of the existingterrain for the engineer, who can plan & design his project keeping

in view the ECONOMY and SAFETY.

LEVELLING


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LEVEL SURFACE: Surface NORMAL to direction of GRAVITY atALL points

- Every point on the level surface will be equidistant from thecenter of the earth

HORIZONTAL PLANE: Plane TANGENTIAL to Level surface at anypoint

VERTICAL PLANE: Plane which contains VERTICAL LINE at aplace

- Vertical liner to Level surface DATUM SURFACE: Arbitrary surface with reference to which the

heights (elevation) of points are measured and compared

REDUCED LEVEL (RL): is the height above or below the datum BACK SIGHT (BS): is the first staff reading taken after setting the

instrument in any position. This will always be a reading on a pointof known height

FORE SIGHT (FS) : is the last staff reading taken on a point beforeshifting the instrument. This will always be a point whose height hasto be determined

TERMINOLOGY - LEVELLING


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INTERMEDIATE SIGHT (IS): refers to any staff reading taken on a point ofUNKNOWN elevation, after the BS and before the FS. Necessary if it isneeded to take more than 2 readings from the same position of instrument.

CHANGE POINT (CP): indicates shifting the instrument. Both the BS and

FS are taken on a change point BENCH MARKING (BM): is a fixed point of reference of known elevation.

The reduced level of bench markis used to determinethe reduced level ofother points

Bench marks are classified as:

a) Great Trigonometrical Survey (GTS) bench marksb) Permanent bench marks

c) Arbitary bench marks

d) Temporary bench marks

BM indicated on a FLAT surface

BM 100.000

BM indicated on a vertical surface

Horizontal groove

Point of reference


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PRINCIPLE OF LEVELLING

(Refer Fig. 8.15 M.S.Palanichamy)

BM A

B

C

BS IS

FS

BS

FS

O1

O2

Explanatory figure of a levelling operation


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LEVELLING INSTRUMENTDUMPY LEVELS

Right Side ViewLeft Side View

Dumpymeans short & thick More stable than other types


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LEVELLING INSTRUMENT:

LEVELLING STAFF

CLASSIFICATION OF LEVELLING


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1) Simple Levelling:

(Dia. Refer MSP)

2) Differential Levelling:

(Dia. Refer MSP)

CLASSIFICATION OF LEVELLING

METHOD - CALCULATING REDUCED LEVELSa) Height of Collimation (Height of Instrument method)b) Rise and Fall method

Height of Collimation Rise and Fall method

1) It is more rapid, saves time and labour 1) Laborious as staff reading of each station iscompared to get RISE or FALL.

2) Adopted for reduction of levels forlongitudinal or cross sectional levelling works

2) Adopted for determining difference in levels of twopoints where precision is required

3) There is no check on the RL of intermediatestations

3) There is complete check on RL of intermediatestations

4) Only 2 arithmetic checks

ie., BS - FS = Last RL First RL

4) 3 arithmetic checks

ie., BS - FS = Last RL First RL = Rise - Fall

DETERMINATION OF AREAS


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1) By dividing the area into number of TRIANGLES

2) Areas between Survey Line and Boundaries

a) Trapezoidal rule

A = d/2 [First ordinate + Last Ordinate + 2 (Sum of intermediateordinates) ]

b) Simpsons rule

A = d/3 [ First ordinate + Last ordinate + 2 (sum of odd ordinates) + 4(sum of even ordinates) ]

DETERMINATION OF AREAS


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BRICKS


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BRICKS

Bricks are obtained by moulding clay in rectangular blocks ofuniform size, then by drying and burning these blocks in brick kilns.

QUALITIES OF GOOD BRICKS:1) should have perfect edges, well burnt in kilns, copper colored, free

from cracks , with proper rectangular shape and std. size (19 x 9 x 9)

2) Should give clear ringing sound, when struck with each other3) Must be homogeneous, void free

4) Percentage absorption of water by weight < 20 - for Ist class brick& 22 % - IInd class brick, when soaked in cold water for 24 hrs.

5) Should be sufficiently HARD. Avg. Wt.,: 3 3.5 Kg

6) Should not break when dropped from a height of 1m.7) Should not show deposits of SALT, when immersed in water anddried.

CLASSIFICATION OF BRICKS:


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1) Ist class : table mounted, std. shape, comply with all good qualities ofbricks, used for superior and permanent works.

2) IInd class: ground moulded and burnt in kilns, surface of brickrough& irregular

3) IIIrd class: ground moulded and burnt in clamps. They are NOT hard,but Rough with irregular and distorted edges.- Gives dull sound when struck with each other.

4) Overburnt bricks irregular shape and dark color. Used asaggregates for concrete in foundations, floors, roads, etc.,.

USES OF BRICKS:Construction of walls,Hollow bricks used for insulation purpose,Fire bricksmade of fire clay, used as refractory material,

CONSTITUENTS OF BRICK:1) ALUMINA: 20 30% Al2O32) SILICA: Exists in clay in free or combined form. (50 60% Silica),

prevents cracking, shrinking and warping3) LIME: < 5% , (prevents shrinking in raw bricks)4) OXIDE OF IRON: < 5% , Gives RED color to bricks.

5) MAGNESIA: Gives YELLOW tints to bricks. Reduces Shrinkage

STONES


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Are obtained from ROCKS.

QUALITIES OF GOOD STONE:1) Crushing strength of stone > 100 N/mm2) Uniform color

3) Durable

4) Easily carvable

5) Fracture sharp and clear6) For road resist wear and tear7) Acid and Fire resistant

USES OF STONES:

1) In construction of buildings2) For Foundations, walls, floors, etc.,

3) Ballasts in railways

STONES

CEMENT


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CEMENT

Obtained by burning @ very high temp. (Calcareous + Argillaceous materials)Calcined product is known as CLINKERSmall quantity of GYPSUM is added to CLINKER and is pulverised into

very fine powder known as CEMENT.On SETTING, cement resembles a variety of SANDSTONE found in PORTLANDin England, and is therefore called PORTLAND CEMENT.

GOOD QUALITIES OF CEMENT:1) Uniform color2) Cool when felt with hand3) Free from lumps4) When ignited, cement should not loose >4% of its weight5) Sulphur < 2.75%6) Magnesia < 5%

TYPES :Quick Setting Cement, Hydrophobic cement, Coloured cement, High Strength cement

CONCRETE


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CONCRETE

Is a mixture of (cement, sand, crushed rock and water) - which when placed in askeleton of forms and allowed to cure, becomes hard such as stone.

Properties of Concrete:1) High compressive strength2) Free from corrosion3) Hardens with age4) As it is weak in tension, steel reinforcement is placed in it to take up thetensile stresses. This is termed as Reinforced Cement Concrete

5) Has tendency to be porous

Uses of Concrete:1) Concrete can be made impermeable by using hydrophobic cement.2) In massive structures such as dams and bridges

3) Prestressed concrete is a relatively new type of concrete, which is used inmany constructions particularly in construction of bridges.

STEEL SECTIONS


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Steel is very ductile and has elastic properties

Mild Steel having Carbon content : 0.1 0.25% is used for structural

work

MARKET FORMS:

STEEL SECTIONS

STEEL BARSSTEEL PLATES

Length: 10 12 m, Dia: 6 32mm

Rolled plates have max. area = 30 m2

Thickness = 5 28 mm

< 5 mm (Sheets)


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FLATS :Much longer than plates and shorter width

ANGLE SECTIONS Used in construction of steel roof trusses,

Steel columns, steel beams and stiffners

CHANNEL SECTIONSWeb

FLANGE


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I SectionPopularly known as RolledSteel (R.S) Joists or beams

T - Section


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DIAMOND MESH

RIBBED MESHEXPANDED METAL

unit - i basic civil and mech

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