Curve Lay - Out
By
Deflection Angle
Low-Volume Road Design
FE 346
Winter Quarter
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Curve Lay - Out By Deflection Angle |
Low-Volume Road Design FE 346 Winter Quarter |
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DEFLECTION ANGLES FOR
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CURVE
RADIUS |
DEFL ANGLE/ FOOT |
Cord Lengths and Deflection
Angle
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20 FT Cord |
25 FT Cord |
30 FT Cord |
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40 |
42.9718 |
14 |
18 |
20 |
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50 |
34.3775 |
11 |
14 |
17 |
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60 |
28.6478 |
10 |
12 |
14 |
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70 |
24.5553 |
8 |
10 |
12 |
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80 |
21.4859 |
7 |
9 |
11 |
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90 |
19.0986 |
6 |
8 |
10 |
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100 |
17.1887 |
6 |
7 |
9 |
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EXAMPLE FOR RUNNING 50 FT RADIUS CURVE USING A 25 FT CORD
Note: The first deflection angle ONLY is 14 degrees, all others are double at 28 degrees. This is due to the fact that the 140 defl. angle is turned from a line tangent to the curve ( PC ).
