How to calculate various parts of horizontal circular curve

In this construction video tutorial, S.L. Khan, the renowned civil engineers, gives brief lectures on how to define various parts of horizontal circular curve ranging from road curve, railway track curve or other structure curve.

By going through this tutorial, you will gather knowledge on curve length, curve chord length, tangent length, mid ordinate, apex distance, radius if chord and mid ordinate are recognized.

In the video, there is a horizontal curve and deflection angle is taken as Ø = 100⁰ and radius of the curve is taken as R = 500 ft.

It is known fact that in circular curve deflection angle and central angle are same.

On the basis of the above dimension, you have to determine the followings :-

• Curve Length
• Curve chord length
• Tangent Length
• Mid ordinate
• Apex distance

These are the unidentified parts of the curve.

Solution :-

Computation of Tangent Length :-

Tangent length stands for the distance among tangent point of the curve and intersection point of the curve. For the calculation purpose, the following formula is used :-

Tangent Length = R tan Ø/2

So, T.L = 500 x Tan(50) (as the value of tangent is equal to halt deflection angle)

So, Tangent Length = 595.87 ft.

To find out the value of curve length, curve chord length, mid ordinate and apex distance, watch the following video tutorial.