HORIZONTAL CURVE FORMULAS
D | = Degree of Curve, Arc Definition
| 1° | = 1 Degree of Curve
| 2° | = 2 Degrees of Curve
| P.C. | = Point of Curve
| P.T. | = Point of Tangent
| P.I. | = Point of Intersection
| I | = Intersection Angle; Angle between two tangents
| L | = Length of Curve, from P.C. to P.T.
| T | = Tangent Distance
| E | = External Distance
| R | = Radius
| L.C. | = Length of Long Chord
| M | = Length of Middle Ordinate
| c | = Length of Sub-Chord
| k | = Length of Arc for Sub-Chord
| d | = Angle of Sub-Chord
|
|
|
R = | L.C. | | T = R tan(I/2) = | L.C.
| |
| 2 sin(I/2) | 2 cos(I/2)
|
L.C. | = R sin (I/2) | | D1° = R = 5,729.58 | | D2° = | 5,729.58 | | D = | 5,729.58
| | |
| 2 | 2 | R
|
M = R [1 - cos(I/2)] = R - R cos(I/2)
E + R | = sec(I/2) | | R - M | = cos(I/2)
| |
| R | R
|
c = 2R sin(d/2) | | d = | kD
|
| 100
|
L.C. = 2R sin(I/2) | | E = R [sec(I/2) - 1] = R sec(I/2) - R
|
|