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COMPUTER AIDED DESIGN LABORATORY SUBJECT CODE : 10CVL58 IA MARKS : 25 NO. OF PRACTICAL HOURS/WEEK : 03 EXAM HOURS : 03 TOTAL NO. OF PRACTICAL HOURS : 42 EXAM MARKS : 50 EXERCISE 01: ANALYSIS OF A FIXED BEAM USING STAAD EXERCISE 02: ANALYSIS OF A PROPPED CANTILEVER BEAM USING STAAD EXERCISE 03: ANALYSIS OF A CONTINUOUS BEAM USING STAAD EXERCISE 04: ANALYSIS OF A CONTINUOUS BEAM USING STAAD EXERCISE 05: ANALYSIS OF A SINGLE STORIED 2D PORTAL FRAME USING STAAD EXERCISE 06: ANALYSIS OF A DOUBLE STORIED 2D PORTAL FRAME USING STAAD EXERCISE 07: INTRODUCTION TO AUTOCAD DRAWING TOOLS EXERCISE 08: INTRODUCTION TO AUTOCAD MODIFYING TOOLS EXERCISE 09: AUTOCAD DRAWING: FOUNDATION EXERCISE 10: AUTOCAD DRAWING: STAIRS EXERCISE 11: AUTOCAD DRAWING: LINTELS AND CHEJJA EXERCISE 12: AUTOCAD DRAWING: RCC SLABS AND BEAMS EXERCISE 13: AUTOCAD DRAWING: RESIDENTIAL BUILDING EXERCISE 14: AUTOCAD DRAWING: PUBLIC BUILDING EXERCISE 15: EXCEL APPLICATION: SFD and BMD Exercise 16: Excel Application: Design of Singly Reinforced Beam Exercise 17: Excel Application: Computation of Earthwork Exercise 18: Excel Application: Computation of Earthwork Exercise 19: Excel Application: Design of Horizontal Curve Exercise 20: Excel Application: Design of Super Elevation Department of Civil Engineering, SMVITM. Bantakal

Surveying Practice -II Lab Manual

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STUDY OF INSTRUMENTS

COMPUTER AIDED DESIGN LABORATORY

Subject Code : 10CVL58 IA Marks : 25

No. of Practical Hours/Week : 03 Exam Hours : 03

Total No. of Practical Hours : 42 Exam Marks : 50Exercise 01: Analysis of a Fixed Beam Using STAADExercise 02: Analysis of a Propped Cantilever Beam Using STAADExercise 03: Analysis of a Continuous Beam Using STAADExercise 04: Analysis of a Continuous Beam Using STAADExercise 05: Analysis of a Single storied 2D Portal Frame Using STAADExercise 06: Analysis of a Double storied 2D Portal Frame Using STAADExercise 07: Introduction to AutoCAD Drawing ToolsExercise 08: Introduction to AutoCAD Modifying ToolsExercise 09: AutoCAD Drawing: FoundationExercise 10: AutoCAD Drawing: Stairs

Exercise 11: AutoCAD Drawing: Lintels and ChejjaExercise 12: AutoCAD Drawing: RCC Slabs and Beams Exercise 13: AutoCAD Drawing: Residential BuildingExercise 14: AutoCAD Drawing: Public Building

Exercise 15: Excel Application: SFD and BMDExercise 16: Excel Application: Design of Singly Reinforced Beam

Exercise 17: Excel Application: Computation of EarthworkExercise 18: Excel Application: Computation of EarthworkExercise 19: Excel Application: Design of Horizontal CurveExercise 20: Excel Application: Design of Super Elevation

any desired position. This vertical circle may be used to measure the vertical angle and for making line of sight horizontal.

3. Index frame or T-frame:

It is a T- shaped frame consisting of vertical leg known as clipping arm and horizontal arm known as index arm. At the either ends two verniers are attached to read to vertical angle. Altitude bubble is attached on the top of the index frame for the levelling purpose.

4. Standards or A-Frame:

Two standards resembling a are mounted on the upper plates. The trunnion axis, index frame and arms of vertical circle are attached to the A-Frame.

5. Lower plate [scale plate]:

It carries a horizontal circle graduated from 0 to 360 lower clamp screw and corresponding tangent screw are provided for accurate setting. Usually the size of the theodolite is represented by the size of the horizontal plate.This plate level is fixed parallel to the trunnion axis and is used for the levelling of the instrument.

7. Altitude level:

It is provided parallel to the vertical circle and fixed on the top of the vertical circle. It is used for levelling during measurement of vertical angle.

Terms and definitions

1. Transiting:

It is the process of resolving the telescope in the vertical plate through 180 about a horizontal axis by transiting the line of sight is reversed. Hence this process is also called as plugging or reversing.

2. Centering:

The process of setting the theodolite exactly over that station point is called centering . Centering can be done by using a plumb bob or with the help of optical plummet.

3. Swinging the telescope:

It is the process of rotating the instrument in the horizontal plane about the vertical axis. If the telescope is rotated in the clockwise direction, it is called swing right and if it is rotated in anticlockwise direction then it is called as swing left.

4. Face left:

If the vertical circle is kept to the left side of the observer then it is called Face left and the corresponding observations are called Face left observations.

5. Face right:If the vertical circle is kept to the right side of the observer then it is called Face Right and corresponding readings are called Face Right observations.

6. Telescope normal:

A telescope is said to be normal or direct when the face of the vertical circle is to the left and the bubble of the telescope is at the top.7. Telescope inverted:

A telescope is said to be inverted or reversed when the vertical circle is to the right and the bubble is at the bottom or downFundamental axis of theodolite:

1. Vertical axis:It is an axis about which the instrument can be rotated in a horizontal plane.

2. Horizontal or trunnion axis:

It is an axis about which the telescope can be rotated in vertical plane.

3. Line of collimation: It is the line passing through the intersection of the horizontal and vertical cross hairs and optical centre of the object glass.

4. Axis of plate level:

It is the straight line tangential to the longitudinal curve of the level tube at its centre. The axis of level tube is horizontal when the bubble is at the centre.

Exercise No:1.1

Measurement of Horizontal Angles with method of Repetition using Theodolite.AIM: To determine the horizontal angle between the given poles from the given point O, using theodolite by method of repetition.Instruments Required: Theodolite with tripod, ranging rod.

Theory:In this method an angle is measured more than two times, allowing the vernier to remain clamped each time at the end of each measurement, instead of setting it back at zero when sighting at the previous station. Thus angle is mechanically added several times depending upon the number of repetitions. The average horizontal angle is obtained by dividing the final reading by the number of repetitions. The repetition method is adopted when a repetition theodolite with a slow motion screw for the lower plate is available.

PROCEDURE: The method of repetition is used to measure a horizontal angle to a finer degree of accuracy than that obtainable with the least count of the vernier. 1. Set the instrument at Q & level it. With the help of upper clamp & tangent screws, set 00 reading on vernier A. Note the reading of vernier B (reading should be 1800).2. Loose the lower clamp & direct the telescope towards the point P, clamp the lower clamp & bisect point P accurately by lower tangent screw.3. Unclamp the upper clamp & turn the instrument clockwise about the inner axis towards R. Clamp the upper clamp & bisect R accurately with the upper tangent screw. Note the reading of verniers A & B to get the approximate value of the angle PQR.

4. Unclamp the lower clamp screw & turn the telescope clockwise direction & bisect P again. Bisect P accurately by using the lower tangent screw. It should be noted that the vernier readings will not be changed in this operation, since the upper plate is clamped to the lower.5. Unclamp the upper clamping screw & turn the telescope clockwise & sight R. Bisect R accurately by upper tangent screw.6. Repeat the process until the angle is repeated the required number of times.

The average of horizontal angle with face left will be equal to final reading divided by 3.

7. Change face and make 3 more repetition as described above. Find the average angle with face right, by dividing the final reading by 3.8. The average horizontal angle is then obtained by taking the average of the 2 angles obtained with face left & face right.

OBSERVATION & TABULATION :

Instrument atSighted toFace LeftFace RightAverage Horizontal Angles

Ver AVer BMeanNo. of repetitionHorizontal AnglesVer AVer BMeanNo. of repetitionHorizontal Angles

ooooooo

QP

R

P

R

P

R

RESULT:

Average of horizontal angle by repetition method =

Exercise No:1.2Measurement of Horizontal Angles with Reiteration method of using TheodoliteAIM: To measure horizontal angles by Reiteration method using theodolite.Instruments Required: Theodolite with tripod, ranging rod, arrow.

Theory:Reiteration is another method of measuring horizontal angle with high precision. It is generally preferred when several angles are to be measured at a station. In this method several angles are measured successively and finally the horizon is closed. The final reading of the vernier (vernier A) should be same as initial reading. If not error is equally distributed among all the measured angles. Suppose it is required to measure the angle AOB, angle BOC, angle COD, angle DOA shown in fig procedure is as follows.PROCEDURE:The method known as direction method or Reiteration method or Method of series is suitable for the measurement of the angles of a group having a common vertex point. Several angles are measured and finally the horizon is closed.To measure angles AOB, BOC, COD, DOA by reiteration method.

1. Set the instrument over O & level it. Set the vernier to zero & bisect point A accurately.2. Release the upper clamping screw & turn the telescope clockwise, bisect the station B using the upper tangent screw. Read the verniers. The mean of the vernier readings will give the angles AOB.3. Similarly bisect successively C, D, thus closing the circle. Read both the verniers at each bisection. Since the graduated circle remains in a fixed position through out the entire process, each included angle is obtained by taking the difference between two consecutive readings. 4. On final sight to A, the reading of the vernier should be the same as the original setting. If not, note the reading & find the error due to slips etc.& if the error is small, Distribute it equally to all angles. If large, repeat the process and take a fresh set of reading.5. Repeat steps 2 & 4 with the other faceOBSERVATION & TABULATION :

Instrument atSighted toFace LeftFace RightAverage Horizontal Angles

Ver AVer BMeanHorizontal AnglesVer AVer BMeanHorizontal Angles

ooooooo

OA

B

C

D

A

RESULT:

Average horizontal angle by reiteration method =

Exercise No:1.2

Measurement of Vertical Angles using TheodoliteAIM: To Measure vertical angle between two points A & B.Instruments Required: Theodolite with tripod, arrows, ranging rods, and plumb bob.Theory:

Vertical Angle Is the Angle which the Inclined Line of Sight to an object makes with the Horizontal .It may be an angle of Elevation or Depression depending upon whether the object is above or below the Horizontal Plane passing through the trunion axis of the instrument.PROCEDURE:1. Set up the instrument over O and level it accurately with reference to the altitude bubble and plate level.

2. Set zero of the vertical vernier to exactly zero of vertical circle by means of vertical circle, clamping screw and tangent screw.

3. Bring the bubble of altitude level to the centre of its run by means of clip screws. The line of collimation is thus made horizontal when the vernier reads zero.

4. Unclamp the vertical circle clamp and direct the telescope towards A and when it is sighted approximately clamp the vertical circle and bisect A exactly by turning a tangent screw.

5. Read both verniers . The mean of two readings gives the value of required angle.

6. Change the face and repeat the Process. Mean of two Readings gives the second value of required angle.

7. The average of two values thus obtained gives the value of required angle which is free from instrumental error.

OBSERVATION & TABULATION :

Instrument atSighted toFace LeftFace RightAverage Vertical Angles

Ver CVer DMeanVertical AnglesVer CVer DMeanVertical Angles

ooooooo

OA

B

RESULT:

Measurement of vertical angle is ..

Exercise No:2.1

Determination of elevation of an object using Single Plane Method(Base is accessible)

AIM: To measure the elevation of an object when base is accessible.Instruments Required: Theodolite with tripod, tape & leveling staff, ranging rods, arrows.

Theory:

. Let P = Instrument station.

Q = point to be observed.

A = Centre of the instrument.

Q = Projection of Q on horizontal plane through A.

D = AQ = Horizontal distance between P and Q.

h = height of the instrument at P.

h = QQ.

S = Reading on staff kept on BM with the line of sight horizontal.

= Angle of elevation from A to Q.

From AQQ, tan = h /D

h = D tan

RL of Q = RL of BM + S + hPROCEDURE:

1. Level the instrument with reference to the altitude bubble and set the vernier scale C and D reading to zero using vertical clamp and tangent screw.

2. Hold the staff on the bench mark and note down the back sight staff reading, S.

3. Hold the staff at the base of the object and note down the staff reading, S1.

4. Measure the horizontal distance between A and Q, i.e., AQ

5. Rotate telescope to the object whose vertical angle is to be noted and read both vernier C and D of the vertical circle with face left.

6. Repeat the observation with face right and calculate the average vertical angle OBSERVATION & TABULATION :

Instrument StationSighted toFace LeftFace RightAverage Vertical Angle

Ver CVer DMeanVer CVer DMean

ooooo

AQ

CALCULATION:

h = D tan

RL of Q = RL of BM + S + h

Base reading at the base of the object (S1) =

Height of the object = S1 + h

RESULT:

1. The elevation of the object =

2. The height of the object =

Exercise No:2.2Determine of elevation of an object using Single Plane Method (Base is inaccessible)AIM: To determine the elevation of given object when its base is inaccessible using single plane method.Instruments Required: Theodolite with tripod, tape, leveling staff, ranging rods, arrows.

Theory:

In few practical cases, it may not be possible to reach the base of the object whose height or elevation is needed or its horizontal distance from a known point. Figure2.2 shows such a case where the instrument axis is at different levels. If S1 and S2 are the corresponding readings on staff kept on BM and if the difference in the level of the axis of the instrument is S2-S1 (if axis at B is higher) or S1-S2(if the axis at A is higher). Let Q be the projection of Q on horizontal line through A and Q be the projection on horizontal line through B.

Axis at B is higher:

From QAQ, h1 = D tan 1 ---------- (1)

From QBQ, h2 = (b + D) tan2 ---- (2)

Now, h1-h2 = S2-S1 = S

S = D tan 1 (b + D) tan2S = D tan 1 D tan2 b tan 2S = D (tan 1 tan2) b tan 2D = RL of Q = RL of BM + S1 + h1Check: RL of Q = RL of BM + S2 + h2PROCEDURE:

1. Set up the theodolite at P and level it accurately with respect to the altitude bubble.

2. Direct the telescope towards Q and bisect it accurately. Clamp both the plates. Read vertical angle 1.3. With the vertical vernier set to zero, and altitude bubble in the centre of its run, take the reading on the staff kept at the nearby BM.

4. Transit the telescope so that the line of sight is reversed. Mark the second instrument station R on the ground. Measure the distance RP, i.e., b accurately.

5. Direct the telescope towards Q and bisect it accurately. Clamp both the plates. Read vertical angle 2.6. With the vertical vernier set to zero, and the altitude bubble in the centre of its run, take the reading on the staff kept at the nearby BM.

OBSERVATION & TABULATION :

Instrument atSighted toFace LeftFace RightAverage Vertical Angle

Ver CVer DMeanVer CVer DMean

ooooo

PQ

RQ

CALCULATION:

1 =

2 =

S1 =

S2 = b = D = =

h1 = D tan1 R.L of Q= R.L of B.M +S1 + h1RESULT:

1. Horizontal distance between instrument station and tower =

2. Elevation of top of object = Exercise No: 3.0Determine of distance and difference in elevation between two inaccessible points using Double Plane Method.AIM: To determine the distance and difference in elevation between two inaccessible point using double plane method.Instruments Required: Theodolite with tripod, arrows, ranging rods, tape & leveling staff.

Theory:

It is also possible to determine distance to an object from a known point and elevation of top of the object by selecting points of observation randomly. In the figure 3.0, AQ is the horizontal line through A. Q being the vertical projection of Q. Thus, AQQ is a vertical plane. Similarly, BQQ is a vertical plane, Q being the vertical projection of Q on the horizontal line through B. PRQ1 is a horizontal plane, Q1 being the vertical projection of Q and R vertical projection of B on a horizontal plane passing through P. 1 and 2 are the horizontal angles, and 1 and 2 are the vertical angles measured at A and B respectively.

From AQQ, QQ = h1 = D tan 1

From PRQ1, PQ1R = (1 + 2)

From sine rule, = =

RQ1= D1 =

PQ1=D1 = h1 = D1 tan 1

h2 = D2 tan 2RL of Q = RL of BM+S1 +h1

Check: RL of Q = RL of BM+S2 +h2PROCEDURE:

1) Let P and R be the two instrument stations and Q is the object.

2) Set the instrument at P and level it accurately with respect to the altitude bubble.

3) Measure the angle of elevation 1 to Q.

4) Sight the point R with reading on the horizontal scale as zero and measure the horizontal angle 1 at P.

5) Take a back sight S on the staff held on the BM with line of sight horizontal.

6) Shift the instrument to R and measure 2 and 2 there.

OBSERVATION & TABULATION :

Horizontal angle:

Instrument atSighted toFace LeftFace RightAverage Horizontal Angle

Ver AVer BMeanVer AVer BMean

ooooo

PQ

RQ

Vertical angle:

Instrument atSighted toFace LeftFace RightAverage Vertical Angle

Ver CVer DMeanVer CVer DMean

ooooo

PQ

RQ

Calculation:1 =

2 = S1 =

S2 =1=

2 =b =

D1 =

D1 = h1 = D1 tan 1

h2 = D2 tan 2RL of Q = RL of BM+S1 +h1

Check: RL of Q = RL of BM+S2 +h2RESULT:

1. Distance between P and Q= 2. Elevation of top of station Q=.Exercise No: 4.0Determination of Tacheometric constants and to find the distance and elevationAIM: To determination of tacheometric constants and to find the distance and elevation of the point when, a) Line of sight is horizontal

b) Line of sight is inclined.

Instruments Required: Theodolite with tripod, arrows, ranging rods, tape & leveling staff, plumb bob.

Tacheometric constants K & C

When Line of Sight is horizontal

When Line of Sight is inclinedTheory:

Tacheometry is an indirect method by which horizontal distances and differences in elevation are determined using subtended intervals and angles observed with a transit or theodolite on a graduated scale. Tacheometry eliminates operation of taping, therefore, it is very useful for rough terrains such as rivers, valleys, steep slopes, broken grounds, stretches of water, etc., PROCEDURE:To determine the tacheometric constants K & C.

1) Measure a line about 60m long on a fairly level ground and drive arrows at intervals of 20m.

2) Hold the staff adjacent to the arrows and observe the corresponding staff intercept with line of sight horizontal.

3) Knowing the values of distance (D) and staff reading(S) for different points, the number of simultaneous equations are found by substituting the values of D and S in the formula D =KS + C.4) The solution of the successive pairs of equations will give the values of K and C.

To find the distance and elevation of the point when Line of Sight is horizontal.

1. Hold the staff on the given point and take staff reading corresponding to top, middle and bottom cross hair and staff intercept is calculated.

2. The values of K, S and C are substituted in the distance formula D =KS + C. The distance of that point from the instrument is obtained.

3. The staff reading on the BM of known elevation is taken and hence the elevation of the given point is calculated.To find the distance and elevation of the point when Line of Sight is inclined.

1. Hold the staff on elevated point on the ground and observe the staff reading corresponding to all the three hair and staff intercept S is obtained.

2. The values of K, C and S are substituted in the distance formula,

D = KS cos2 + C cos .

Thus the distance is obtained.

3. The staff reading taken on the BM and by calculating vertical intercept V, the elevation of the point is obtained.OBSERVATION & TABULATION :

To determine the tacheometric constants K & C.

Staff StationDistanceStaff ReadingStaff Intercept

TopMiddleBottom

Distance Formula

D = Ks + C

To find the distance and elevation of the point when Line of Sight is horizontal.

Staff reading on BM , h =

Staff intercept, s =

Staff reading corresponding to middle hair, r =

The horizontal distance of the point from the instrument, D = Ks + C

Elevation of point = RL of BM + h r

To find the distance and elevation of the point when Line of Sight is inclined.

Staff reading on BM , h =

Staff intercept, s =

Staff reading corresponding to middle hair, r =

Vertical intercept, v = Ks Cos . Sin + C Sin

The horizontal distance of the point from the instrument, D = K.s. Cos2 + C. Cos

Elevation of point = RL of BM + h + v r RESULT:1 Tacheometric Constantsi). Multiplying constant K= ii). Additive constant C=2 Distance and elevation of the point when Line of sight is horizontali). Distance=

ii). Elevation=

3 Distance and elevation of the point when Line of sight is inclinedi). Distance=

ii). Elevation=Exercise No: 5.1To set out simple curve using linear method perpendicular offsets from long chord.AIM: To set out a simple curve for the given problem by linear method by taking perpendicular offsets from long chord.Instruments Required: Ranging rods, cross- staff, tape, chain & arrows.

Theory: The midpoint of the long chord is given by

Oo = Where, Oo = Mid-ordinate

R = Radius of the curve

L = Length of the long chord measured on the ground

Length of perpendicular offset at any distance x form midpoint of the long chord is given by

Ox = - (R-Oo)

PROBLEM:

Given:

Length of the long chord (L) = 10

Mid ordinate (Oo) = 1m

Interval along the long chord (x) = 2.5mPROCEDURE:1. Set T1 and T2 at distance of 80m on level ground and divide T1 and T2 and locate mid point.

2. Measure 10m distance on either side of mid point along long chord and locate points.3. Calculate the Radius using the formula,

O0 =

4. Calculate the ordinates of remaining points using the formula,

Ox =

5. Knowing the value of the perpendicular offsets (ordinate) from each of offset points on ground by using cross staff at various points. i.e O10, O20, O30 etc are located at a distance of 10, 20, 30.etc. from mid point of long chord.

6. Join ends of all these perpendicular offsets to get smooth simple curve.

OBSERVATION & TABULATION :

Distance from mid of long chord in m Perpendicular Offset in m

RESULT:

Simple curve is set on the ground and observed

Exercise No: 5.2To set out Simple curve using linear method offsets from chords produced.AIM: To set out a simple circular curve by the method of deflection distances (offsets from chords produced). Instruments Required: Ranging rods, tape, chain & arrows.

Theory: The method is very much useful for long curves and is generally used on highway curves when a theodolite is not available.PROBLEM:

Two tangents intersect at chainage=1000m, the deflection angle 500. Set out a curve of 25m radius to connect the 2 tangents by the method of deflection distance. Take peg interval of 10m

PROCEDURE:1) Locate the tangent point T1 and obtain its chainage as per the calculation. Calculate the length of first subchord(C)2) With zero at T1 spread the chain along first tangent point A1 on its such that T1A1= C= length of first subchord.3) With T1 as center, T1A1 as radius. Swing the chain such that arc A1.A=O1,O1=Fix the point A on the curve.4) Now stretch the chain along T1A & pull it straight in the direction point B2 such that zero of chain at A and distance

5) With zero of chain center at A and AB2 as radius, swing the chain to point B. Such that B2B= O2= Length of second offset of point B on the curve. O2 =.

6) Now stretch a chain along AB and repeat the step 4 and 5 till tangency T2 is reached

OBSERVATION & CALCULATION:

Tangent Length , T= R tan =Length of curve, L= = Given chainage of point of intersection = 1000mChainage at T1= Chainage of P.I- Tangent Length

Chainage at T2= Chainage at T1+ Length of curve

No. of intermediate chords= Total No. of chords=

Length of 1st sub chord, C1=

C2= C3= C4 = C5

C6=FormulaLength of offset

O1=

O2 =.

O3 = O4= O5=

O6 = .

Where c = First Subchord

C = Intermediate Chords

c = Last SubchordRESULT:The curve is set out on the ground and observed.Exercise No: 6.0To set out Simple curve using Rankines deflection angles method.AIM: To set out a simple curve by Rankines deflection angles method (tangential angle).Instruments Required: Theodolite with tripod, Ranging rods, arrows, tape. SHAPE \* MERGEFORMAT

Theory:

A deflection angle to any point on the curve is the angle at P.C between the back tangent and the chord from P.C to that point.

Rankines method is based on the principles that the deflection angle to any point on a circular curve is measured by one-half the angle subtended by the arc from P.C to that point. It is assumed that the length of the arc is approximately equal to its chord.

PROBLEM:

Two tangents intersect at a chainage of 1000m, the defelection angle being 280. Calculate all the data necessary. Set out a simple curve of 25m radius by Rankines method and tabulate the results. Peg intervals becomes 2m, least count of the theodolite is 20sec.PROCEDURE:1) Set the theodolite at the point T1 with both the plates clamped to zero, direct the theodolite to bisect the point of intersection (V). The line of sight is thus in the direction of the rare tangent.2) Release the verniers plate. Set the angle 1 on the vernier. The line of sight is thus directed along T1A.3) With the zero end of the tape pointed at T1 and arrow held at distance T1A=C1 along it. Rotate the tape around T1, till arrow is bisected by the cross-hair. Then the first point A is fixed.

4) Set the second deflection angle 2 on the vernier so that, the line of sight is directed along T1A.5) With the zero end of the tape pinned at A and arrow head at a distance AB=C2 along it.

6) Move the tape around A till the arrow is bisected by cross-hair, thus fixing the point B.

7) Repeat the procedure till the last T2 is reached.CHECK:The last point S0 located must co inside with the point of tangency (T2). If the error is small, last few pegs may be adjusted. If the error is more, the whole curve should be reset.OBSERVATION & CALCULATION:

Radius of curve =

Deflection angle, =

Tangent Length , T= R tanLength of curve, L= Given chainage of point of intersection (V) =

Chainage at T1= Chainage of P.I- Tangent Length

Chainage at T2= Chainage at T1+ Length of curve

No. of intermediate chords= Length of 1st sub chord =

Length of last sub chord =

Points

Chainage in m Chord length in mTangential angle,

n= Formulae for Deflection angle

n= n-1+ nDeflection angleActual theodolite reading

000

T1

A

B

C

D

E

F

T2

CHECK:

1. The Final angle of VT1T2 = 2. Length of T1T2 = 2R sin

RESULT:The curve is set on the field and observed.Exercise No: 7.0 To set out Compound curve using angular metods using Theodolite.AIM: To set a compound curve by defelection angle method.Instruments Required: Theodolite with tripod, Ranging rods, arrows, tape.

Theory: A compound curve consists of 2 simple arc of different radius curving in the 50m direction and joint of common tangent point called Point of compound curvature.

Rs=Smaller radius.

Rl= Larger radius.

D1, D2 = common tangents.

1=Deflection angle between rear and common tangent.

2 = Deflection angle between common and forward tangent.

= Total deflection angle.ts =Length of tangent to the arc having smaller radius.

tl =Length of tangent to the arc having larger radius.

From fig, ts = T1D1 = D1D2= Rs tan (1/2)

tL = T2D2 = D2D= Rl tan(2/2)

From triangle BD1D2, We have,

D1B =D1D2. = D2B = D1D.First curve can be set out from T1 and second from D1 by the method of tangent angle.

PROBLEM:

Given that the radius of the first curve is 10m and that os second curve is 14m. the defelection angle between real and common tangents is 1 = 200 and that between common and forward tangents is 2 = 250. Peg interval = 2m.PROCEDURE:1) Compound curve we can set using deflection angle method. Set the theodolite at T1 with vernier A=0, directed along T1B.2) Set the curve T1Das simple curve from radius RS.3) Shift the theodolite to PCC & orient the instrument make vernier A to read an angle (360- 1/2) and bisect the station T1 & clamp the bottom screw.4) Turn the telescope clockwise till the vernier from A reads 00. Now telescope is turned by 1/2 from the long chord T1D, that it is the line of sight is along DD1, which is common tangent to the compound curve.

5) Plunge the telescope. Now the line of sight is along DD2 which is also common tangent for the arc DT2. Set the second point of the curve using deflection angle method till we get point T2.

CHECK:The observation by measuring the angle T1T2 should be equal to

or

OBSERVATION AND CALCULATIONS:

Total deflection angle = 1+ 2

Length of back tangent arc T1D = D1D = ts = Rs tan Length of tangent arc T2D = D2T2 = D2D = tL = RL tan Tangent distance corresponding to shorter radius Ts= ts +

Tangent distance corresponding to Larger radius TL= tL + Length of curve corresponding to shorter radius Ls= Length of curve corresponding to larger radius LL= Chainage at T1= Chainage of P.I- TsChainage at T2= Chainage at T1+ Ls + LL

Chainage at P.C.C= Chainage at T1+ Ls1st curve

Points

Chainage in m Chord length in mTangential angle,

n= Formulae for Deflection angle

n= n-1+ nDeflection angleActual theodolite reading

000

T1

A

B

C

PCC

2nd curve

Points

Chainage in m Chord length in mTangential angle,

n= Formulae for Deflection angle

n= n-1+ nDeflection angleActual theodolite reading

000

PCC

D

E

F

G

T2

RESULT:The compound curve of given radii has been sent out set out by the method of Tangential angles.Exercise No: 8.0 To set out the centre lines of a rectangular room using offset from base line.AIM: To set out centre line of a double rectangular room using offset from base line.Instruments Required: Tape, ranging rod, arrows, chain, lime powder, strings.

PROBLEM:

Set out centre line for a rectangular room with the inside dimension (6X4)m and (4X6)m with wall thickness 0.3m, using offset from base line.PROCEDURE:1. 1) Centre line distance of a rectangular room is calculated.

2. The perpendicular offset to corner of building is marked on a sheet.

3. The perpendicular offset to the corner of the building is established from previous chosen base line. Then it is established by using 3-4-5 method.

4. The offset to base line is established using tape by measuring the required distance along perpendicular line.

5. The other corner position is established by measuring the required distance in the same perpendicular line.

6. Similarly other points are also established.

7. Points are joined using lime powder and string to get the centre line of the room.

8. The accuracy of the work is checked by measuring the diagonal of the roomsRESULT: Centre line of the double rectangular room is set out on the ground. The diagonal length for the room with dimensions (6X4)m = _____________ and (4X6)m = ____________.Exercise No: 9.0 To set out the centre lines of Columns of a building using two base lines at right angles.

AIM: To set out centre line of columns of the building two base lines at right angles.Instruments Required: Tape, ranging rod, arrows, chain, lime powder, strings.

PROCEDURE:

1. Prismatic compass is set at column A and central line AA fixed with respect to north by stretching a string between arrows driven at ends.2. Central line 1-1 which is horizontal to central line AA is marked by setting out right angles by forming a triangles with (3,4,5,rule) using a steel tape.

3. The other central lines of column are marked with reference to central lines AA and as per the plan measurements.

4. The column pits and other lines of the foundation trench of the entire wall are set by measuring distance from the central line on either side of it equal to the trench width.

5. Column pits and outer trench pits are marked on the ground using lime powder.

RESULT:The central line of columns of the given plan is positioned on the side.Total StationTotal station is a modern survey instrument. It is a combination of an electronic theodolite and distance measuring instrument i.e. Distometer(EDM). With the help of this instrument it is possible to do the horizontal and vertical distance as well as angle measurements. It determine the coordinates of a reflector by aligning the instrument cross hairs on the reflector which simultaneously measures horizontal and vertical angles and slope distances. A microprocessor is incorporated in to this instrument which takes the care of recording, reading and necessary computation. The data which are stored in to a memory card can be transferred to a computer where it can be used to produce different types of drawings.

Total station instrument releigh on the basis of propagation, reflection nad reception of light ray. In total station instrument laser beam is generated, which travels from the instrument and reaches to the prism or reflector, after reaching to the prism, it reflects back to the instrument which is again received by a sensor and the measurements aare displayed on a digital screen.

Uses of total station:

1. It measures horizontal and vertical angles to the accuracy of one second.2. It measures horizontal and vertical distances, coordinates, bearings etc.

3. It is also used for setting out the points, lines and curves.

4. It is useful to measure the remote place distances and the elevation of inaccessible objects.

5. It is useful to prepare contour maps.

6. It can be sending or receives data from comport.

Advantages of total station:

1. It is a most precise instrument which requires lesser time compare to the ordinary theodolite.

2. Simultaneous measurement of horizontal and vertical angles and bearings of a point can be taken from a single set up of the instrument.

3. It is very much useful in hill station, steep ground, across a river etc., where it is difficult to use the ordinary instruments.

Department of Civil Engineering, SMVITM. Bantakal

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