- 2081 Chaitra · 6 marks
Rankine's table, IP 2+450 km, 30°, 3° curve
Short answer
Using D = 3° for a 25 m arc, R = 477.46 m, T = 127.94 m, L = 250.00 m. Chainages: T1 = 2322.06 m, T2 = 2572.06 m. Deflection angles δ = 1718.87c/R are tabulated; final check is Δ/2 = 15°00′00″.
The chainage of IP is 2+450 km. Deflection angle is 30°. The curve is 3° with the fixed arc length of 25 m. The peg interval is 30 m. Calculate the setting out table by Rankine's deflection angle method.
Chainage of IP km m, , degree of curve for a fixed arc of 25 m, peg interval 30 m.
Elements
Setting-out table (theodolite at T₁)
minutes:
| Point (chainage, m) | Chord c (m) | δ = 1718.87c/R | Cumulative deflection |
|---|---|---|---|
| 2322.06 | - | - | 0°00′00″ |
| 2340.00 | 17.94 | 1°04′34″ | 1°04′34″ |
| 2370.00 | 30.00 | 1°48′00″ | 2°52′34″ |
| 2400.00 | 30.00 | 1°48′00″ | 4°40′34″ |
| 2430.00 | 30.00 | 1°48′00″ | 6°28′34″ |
| 2460.00 | 30.00 | 1°48′00″ | 8°16′34″ |
| 2490.00 | 30.00 | 1°48′00″ | 10°04′34″ |
| 2520.00 | 30.00 | 1°48′00″ | 11°52′34″ |
| 2550.00 | 30.00 | 1°48′00″ | 13°40′34″ |
| 2572.06 | 22.06 | 1°19′26″ | 15°00′00″ |
Check: final deflection (computed 15°00′00″).
Answer: m, m, m, T₁ = 2322.06 m, T₂ = 2572.06 m; deflection angles as tabulated.
✓ Answer checked by Claude Opus 5.5 (high effort)
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