
Transportation Design Problem 2  Determine elevation of a point on a crest vertical curve:

Given a crest vertical curve connecting an ascending grade of 5% to a descending grade of 3%. The PVC at station 23+00 has an elevation of 197.31. If the vertical curve is designed for a stopping distance of 644.1 feet at 65 mph, what are the elevations of the PVI and PVT? 
1. From the transportation submenu open the length crest vertical curve stopping sight distance calculation, CrstVrtCrvStop.aspx. Input the "Title" of the calculation, the "Designer/Checker" information and the variables.
Click on the "Calculate" button. Read the results. The length of the crest vertical curve based on stopping sight distance is 1537.96 feet.


2.
From the transportation submenu open the rate of grade change calculation, GrdChngRt.aspx. Input the "Title" of the calculation, the "Designer/Checker" information and the variables.
Click on the "Calculate" button. Read the results. The rate of grade change is 0.01 %/ft.


3. From the transportation submenu open the vertical curve point elevation calculation, VertCrvPntEl.aspx. Input the "Title" of the calculation, the "Designer/Checker" information and the variables.
The distance to PVI is LC/2 = 1537.96/2 = 768.98 feet. Enter 7.69 for distance in stations. Click on the "Calculate" button. Read the results. The elevation of the PVI is 235.46 feet.


4. Still working in the vertical curve point elevation calculation, VertCrvPntEl.aspx. Input any changes to the "Title" of the calculation, the "Designer/Checker" information.
Change the input variables. For grade entering the vertical curve enter the descending grade of 3%. Change the beginning vertical curve elevation to that of the PVI elevation of 235.46. Click on the "Calculate" button. Read the results. The elevation of the PVT is 212.09 feet.


5. Summary

The elevation of the PVI is 235.46 feet. The elevation of the PVT is 212.09 feet.

