An engineer is assigned to design a vertical curve for a hig

An engineer is assigned to design a vertical curve for a highway with the design speed of 45mph. Knowing that the gradients are-5% downhill and 3% uphill, what is the minimum design length of the vertical curve?

Solution

For the value of K,

By using equation K = S²/ 2158

Value of Algerbric difference in Grade

A = G1-G2 ( G1 is Uphill, G2 is Downhill)

A = 3 - (-5)

A = 8

For minimum length of Vertical curve , we use equation , L= K*A

hence, putting values of K and A in equation, we get

L = 60*8 = 480 ft

So, The minimum design lenght of Vertical curve is 480 ft.