SIMPLE CURVE
Definition
A simple arc provided in the road to impose a curve between the two straight lines.
GROUP 3
NUR AZURA BINTI ABDUL WAHAB (15DKA15F2020)
VIGNES A/L V R SOMU NAIDU (15DKA15F2022)
SITI KHATIJAH BINTI MOHAMED AFFANDI (15DKA15F2024)
NYANA SAUNTARI A/P SHANMUGAM (15DKA15F2026)
Terminologies In SIMPLE CURVE
PC = Point of curvature. It is the beginning of curve.
PT = Point of tangency. It is the end of curve
PI = Point of intersection of the tangents. Also called vertex
T = Length of tangent from PC to PI and from PI to PT. It is known as subtangent
R = Radius of simple curve, or simply radius
L = Length of chord from PC to PT. Point Q as shown below is the midpoint of L
Lc = Length of curve from PC to PT. Point M in the the figure is the midpoint of Lc
E = External distance, the nearest distance from PI to the curve
m = Middle ordinate, the distance from midpoint of curve to midpoint of chord.
I = Deflection angle (also called angle of intersection and central angle). It is the angle of intersection of the tangents. The angle subtended by PC and PT at O is also equal to I, where O is the center of the circular curve from the above figure
x = offset distance from tangent to the curve. Note: x is perpendicular to T
θ = offset angle subtended at PC between PI and any point in the curve
D = Degree of curve. It is the central angle subtended by a length of curve equal to one station. In English system, one station is equal to 100 ft and in SI, one station is equal to 20 m.
Sub chord = chord distance between two adjacent full stations
DEGREE OF CURVES
The degree of curve is the central angle substanded by an arc or chord of one station
ARC
CHORD
The degree of curve is the central angle sustanded by one station
The degree of curve is the central angle substanded by one station length of chord