mx v8i curve calculation

Curve Calculations

Typical Vertical Curve

Notation

g = Gradient (in %)= Algebraic Difference in grade (in %)

VIP = Vertical Point of IntersectionBVC = Beginning of Vertical CurveEVC = End of Vertical CurveVCL = Vertical Curve Length (measured horizontally)MO = Mid OrdinateK = Rate for Vertical Curvature

Typical Horizontal Circular Curve

Notation

IP = Intersection Point of Tangents

= Deflection AngleRc = Radius of Circular CurveTc = Tangent LengthLc = Length of Circular CurveD = Degree of Circular CurveTC = Point of Change from Tangent to Circular CurveCT = Point of Change from Circular Curve to Tangent

Page 1 of 3Curve Calculations

15-06-2015mk:@MSITStore:C:\Program%20Files%20(x86)\Bentley\MX%20V8i%20(SELECT...

O = Origin of Circular CurveEc = External Distance

Definition of a 1' curve : an arc 100m in length whose radius subtends an angle of 1'ie Dc=1', Rc=5729.578m

(*1) = Measured in Degrees

(*2) = Measured in Radians

Typical Horizontal Curve (with Transition)

Notation

IP = Intersection Points of TangentTS = Point of Change from Tangent to SpiralSC = Point of Change from Spiral to Circular CurveCC = Centre of Circular CurveCS = Point of Change from Circular Curve to SpiralST = Point of Change from Spiral to TangentL = Spiral Arc from TS or ST to any Point on SpiralLs = Spiral Length from TS to SC or ST to CS

= Central Angle of Spiral Arc L

s = Central Angle of Spiral Arc Ls (Spiral Angle)

= Deflection Angle at TS or ST from initial Tangent to any point on Spiral

c = Deflection Angle at TS or ST from initial Tangent to SC or CSDc = Degree of Circular CurveRc = Radius of Circular CurveLc = Length of Circular Curve

= Total Deflection Angle for Curve

c = Central Angle for Circular CurveX = Tangent distance along initial Tangent of any point on Spiral with reference to TS or ST (Xs for SC or CS)Y = Tangent offset from initial Tangent of any point on Spiral (Ys for SC or CS)ST = Short Tangent of SpiralLT = Long Tangent of SpiralLC = Long Chord (TS to SC or CS to ST)p = Offset from initial Tangent to PC of Shifted CircleP = Radial Shift of Circular Curvek = Tangent Distance from TS to PC of Shifted CircleEs = External DistanceTs = Total Tangent Distance (IP to TS or ST)



HT = Half Tangent DistanceC = Correction factor for Spiral Deflection angleA = Parameter of Clothoid

(*1) = Measured in Degrees

(*2) = Measured in Radians

(*3) = Measured in Seconds



mx v8i curve calculation

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