Question

An equal-tangent vertical curve is to be constructed between grades of -2.0% (initial) and +1.0% (final). The PVI is at station 110+00 and at elevation 420 ft. Due to a street crossing the roadway, the elevation of the roadway at station 112+00 must be 424.5 ft. Design the curve.

Answer 1

The answer provides a guided method to design an equal-tangent vertical curve connecting two different grades, factoring in specified elevations at certain stations along the road.

Step-by-step explanation:

To design an equal-tangent vertical curve that satisfies the given constraints, we need to follow a specific strategy involving calculation of the slope and the length of the curve based on the fixed points and grades. Since we have a predefined elevation at Station 112+00 and know the initial and final grades, we can proceed to calculations.

1. Find the length of the vertical curve by using the elevation at Station 112+00 and the PVI elevation.
2. Using the known grades, calculate the length of the tangent sections (tangent distances).
3. Based on these tangent distances, determine the total length of the vertical curve and verify that it complies with design standards.

Given that specific road design standards are not provided, general principles have been applied in the strategy outlined, assuming standard practices for roadway design.