Introduction, Simple Curves, Deflection Angle Method Flashcards
A survey made without the use of basic surveying equipment
Reconnaissance survey
A survey made to pin and mark the points for construction
Preliminary survey
A survey used/undertaken during the construction phase
Final Survey
First step in undertaking a survey
Reconnaissance survey
Second step in undertaking a survey
Preliminary survey
Last step in undertaking a survey
Final survey
Degree of Curve (D) - Arc Basis Formula
D = 1145.916/R
Degree of Curve (D) - Chord Basis Formula
R = 10/sin(D/2)
Point of tangency where the curve
leaves the tangent
Point of Curvature (PC)
Point of
tangency where the curve
meets the other tangent
Point of Tangency (PT)
Point
of where the two tangents meet
Point of Intersection (PI)
Angle of intersection of the tangents
Central Angle (I)
Distance measured from PC or PT to the
vertex or PI
Tangent Distance (T)
Arc length from PC to PT
Length of Curve (LC)
Straight line
drawn from PC to PT
Long Chord (C)
Radius of the circular curve
Radius (R)
Distance measured from the vertex to the midpoint of the curve
External Distance (E)
Measured from the midpoint of the curve to the midpoint of the chord
Middle Ordinate (M)
Formula of Tangent Distance (T)
T = Rtan(I/2)
Formula of Length of Curve (LC)
LC = 20I/D
Formula of Long Chord (C)
C = 2Rsin(I/2)
Formula of External Distance (E)
E = R[1/cos(I/2)-1]
Formula of Middle Ordinate (M)
M = R[1-cos(I/2)]
Formula of Station PC
Sta PC = Sta PI-T
Formula of Station PT
Sta PT = Sta PC+LC
A chord that measures less than the full chord
Subchord (c)
An angle that measures less than the given degree of curve
Subangle (d)
Formula of d1
d1 = c1D/20
Formula of d2
d2 = c2D/20
