Jawaharlal Nehru Technological University Hyderabad
Jawaharlal Nehru Technological University Hyderabad B.Tech II Year SURVEYING AND OFFSHORE STRUCTURES Previous Question Paper (September - 2021 - R18)
Answer any five questions. All questions carry equal marks.
Main
Following are the lengths and bearings of traverse ABCDE:
| Line | Length in m | Bearing |
|---|---|---|
| AB | 229.0 | 198° 59' |
| BC | 131.35 | 282° 14' |
| CD | 80.00 | 320° 13' |
| DE | 199.25 | 35° 13' |
| EA | ? | ? |
Calculate the length and bearing of the line EA which could not be surveyed due to an obstruction in the way.
Answer
To find the length and bearing of the closing line EA, we calculate the latitudes (L = d cos θ) and departures (D = d sin θ) for the known lines AB, BC, CD, and DE.
| Line | Length (m) | Bearing | Latitude (m) | Departure (m) |
|---|---|---|---|---|
| AB | 229.0 | 198° 59' | -216.58 | -74.22 |
| BC | 131.35 | 282° 14' | +27.88 | -128.35 |
| CD | 80.00 | 320° 13' | +61.43 | -51.21 |
| DE | 199.25 | 35° 13' | +162.77 | +114.85 |
| Sum | - | - | ΣL = -24.50 | ΣD = -138.93 |
For a closed traverse, the sum of latitudes and departures must be zero. Therefore, for line EA (length l, bearing θ):
The length of EA is calculated as:
The bearing θ is calculated as:
Since both latitude and departure are positive, the line lies in the first quadrant. Thus, the bearing of EA is 79° 59'.
Write and explain temporary adjustments of theodolite.
Answer
Temporary adjustments of a theodolite are the operations performed at every station where the instrument is set up to prepare it for taking observations. These adjustments must be carried out in a specific sequence to ensure the instrument is ready for measurement.
- Setting up the theodolite: This involves fixing the tripod firmly on the ground and centering the instrument over the station mark using a plumb bob or optical plummet. The tripod head should be leveled approximately by adjusting the tripod legs.
- Centering: After setting up, the vertical axis of the theodolite must be made to pass exactly through the station mark. This is achieved by shifting the instrument on the tripod head until the plumb bob or optical plummet indicates exact alignment.
- Leveling: This step ensures the vertical axis of the theodolite is truly vertical. The plate levels are used for this purpose. The instrument is rotated so that the plate level is parallel to two of the three leveling screws. These two screws are turned simultaneously in opposite directions until the bubble is central. The instrument is then rotated 90 degrees, and the third leveling screw is adjusted until the bubble is centered. This process is repeated until the bubble remains centered in all positions.
- Elimination of Parallax: Parallax is an error caused by the image of the object not being formed in the plane of the crosshairs. It is eliminated in two stages: first, by adjusting the eyepiece until the crosshairs appear sharp and distinct; second, by focusing the objective lens using the focusing screw until the image of the target appears clear and stationary relative to the crosshairs when the observer moves their eye.
The following readings were observed successfully with a levelling instrument. The instrument was shifted after fifth and eleventh readings: 0.585, 1.010, 1.735, 3.295, 3.775, 0.350, 1.300, 1.795, 2.575, 3.375, 3.895, 1.735, 0.635, 1.605. Find the reduced levels of various points, if the reduced level of the point on which the first reading was taken is 136.44m. Use height of instrument method.
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What is meant by contouring? Describe the various methods of contouring and discuss their merits and demerits.
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Define the principle and working of a total station. And list out the various operations that are possible with total station. What are the advantages of total station?
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How bathymetry survey is done by sounding methods, explain in detail.
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Explain the generation of waves in a sea with neat sketches.
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Explain the procedure for safety installation of jacket platform with help of neat diagrams.
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