Title 120 Parabolic Curves.pdf ✅

MSTC 120: Parabolic Curves Vertical Curves are used to connect intersecting gradients in the vertical plane. A simple parabola generally provides a smooth transition between the two gradients Gradients are usually expressed as percentages. Negative gradients are for downgrades, while Positive gradients are called upgrades. The Length of the Curve in vertical curves is taken as the horizontal distance. These are used in the computation of stationing. 1. Types of Vertical Curves 1.1. In terms of Shape In terms of shape, there are two types of vertical curves. A summit curve is such that it has a topmost point. A sag curve, on the other hand, has a bottom-most point.
1.2. In terms of Horizontal Distance There are also two types of vertical curves based on horizontal distances. A symmetric curve is such that a vertical line through the point of intersection (PI) divides the vertical curve into two equal horizontal distances. A non-symmetric curve is the opposite.
2. K, A, R, and L Parameters K Design Speed Related Coefficient A Difference in Gradients r Rate of Change of Gradient L Length of Curve r values are based on the change of grade in every meter station. For example: r = 3% 100 m It is the rate at which the curve passes from one gradient to the next. This means that r = A meter station Expressing the rate of change of grade in percent, K = 100 r In addition, the radius of curvature is R = 100K