Surveying 312339 Manual Practical No.1 Measure the distance between two intervisible survey stations Answer
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| Surveying 312339 Manual Practical No.1 Measure the distance between two inter visible survey stations Answer |
Practical Significance:
Measurement of the length of the line between two intervisible survey stations on flat ground for the planning or construction of any civil engineering projects.
Direct ranging is done when the two end stations of the survey lines are intervisible. When these two survey stations are visible ranging can either done by eye observation or by any other optical instrument like line ranger etc. Ranging is the process of marking the straight line between two survey stations by fixing the intermediate ranging rods.
Required resources/equipment:
| Sr. No. | Resource required | Particulars | Quantity |
| 01 | Metric Chain | 20m/30m | 2 nos. |
| 02 | Metallic or PVC tape | 15m/20m/30m | 2 nos. |
| 03 | Ranging rods | 2m length | 5 nos. |
| 04 | Pegs | Wooden/Steel | 2 nos |
| 05 | Arrows | GI wired | 4 nos |
| 06 | Line ranger | As per IS specification | 2 nos. |
Procedure:
1. First collect the all instruments as mentioned in point no VII from the survey lab.
2. Let, A and B be the two points at the ends of a survey line.
3. First erect the ranging rod on point B while the surveyor stands with another ranging rod at point A.
4. The other assistants will go and hold the ranging rod approximately on line AB.
5. The surveyor at A signals the assistant’s to move transverse to the chain line, till that assistant is
in line with points A and B.
6. By using this procedure the furthermore line can range by the surveyor.
7. After the range of the line measure the distance accurately.
8. After this collect all the instruments and return to the lab.
9. Draw the drawing of a line with accurate measurements and with scale.
Observation Drawing:
Result:
Distance AB = 43.2 m
We Draw the drawing of a line with accurate measurements and with scale.
Practical Related Questions:
1. Explain the procedure of calibration of a chain?
Answer:
STEP 1 – Assign specific duties to the individuals assisting in the test: Two individuals to hold the ends of the chains and apply the right tension, one person to align the 0 ends, and one person to make the comparison at the 100- or 200-foot ends. Layout the chains. Connect the tension handles to the chains. Assuming the chains will be lying on the ground fully supported, a tension of 10-12 pounds will be applied. (Check the chain manufacturer for the exact tension needed for the particular chain.) The persons doing the comparison should each have a magnifying glass for a more precise alignment of the end marks.
STEP 2 – With everyone in position, apply tension to the chains. Have the person at the 0 end communicate with the holders to align the 0’s perfectly. When that is ready, communicate to the person measuring the difference between the calibrated chain and the chain being tested. Constant communication between the participants is the key to a successful comparison of the chains.
STEP 3 – The person doing the comparison should measure and record the difference (estimate to the thousandth of a foot) between the ends of the chains.
STEP 4 – Repeat the test at least three times to obtain an average of the difference in length. Apply any correction for expansion or contraction of the chain because of temperature. Compare the nominal (what length the chain should be) to the calibrated length.
2. Distinguish between Direct and indirect ranging.
