Sample Problem: Vertical Curve Elevation at Any Point

Applying the parabolic equation to find road elevations.

Example

A 200-meter200\text{-meter} equal-tangent crest vertical curve connects an ascending grade of +3.0%+3.0\% (g1g_1) and a descending grade of 2.0%-2.0\% (g2g_2). The Point of Vertical Intersection (PVI) is located at station 10+50010+500 with an elevation of 150.00 m150.00 \text{ m}. Determine the elevation of the curve at station 10+46010+460.

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Sample Problem: Finding the High Point on a Crest Curve

Locating the point of zero slope for drainage design.

Example

Using the same curve parameters as the previous example (L=200 mL = 200 \text{ m}, g1=+0.03g_1 = +0.03, g2=0.02g_2 = -0.02, PVC Station=10+400\text{PVC Station} = 10+400, ElevPVC=147.00 m\text{Elev}_{\text{PVC}} = 147.00 \text{ m}), determine the station and elevation of the highest point on the curve.

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Sample Problem: Minimum Length of a Crest Vertical Curve (Sight Distance)

Ensuring a driver can see over the hill crest.

Example

A crest vertical curve must be designed to connect a +4.0%+4.0\% grade and a 3.0%-3.0\% grade. The required Stopping Sight Distance (SSD) for the design speed is 160 m160 \text{ m}. Assuming the driver's eye height is 1.08 m1.08 \text{ m} and the object height is 0.60 m0.60 \text{ m}, what is the minimum required length of the vertical curve (LminL_{min}) if we assume the curve length is greater than the sight distance (S<LS < L)?

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Sample Problem: Sag Vertical Curve Sight Distance (Headlight Criteria)

Ensuring vehicle headlights illuminate the road far enough ahead in a dip.

Example

A sag vertical curve connects a 4.0%-4.0\% grade to a +2.0%+2.0\% grade. The design speed requires a Stopping Sight Distance (SS) of 130 m130 \text{ m}. Standard headlight height (HH) is 0.60 m0.60 \text{ m}, and the upward divergence angle (β\beta) of the headlight beam is 11^{\circ}. Calculate the minimum required length of the sag curve assuming S<LS < L.

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Case Study: Application of Vertical Curve Types

Analyzing real-world scenarios for crest and sag curves.

Example

A new highway alignment must cross an existing railroad track via an overpass bridge, and immediately afterward pass under a high-voltage power line corridor. Describe the sequence of vertical curves required and the primary engineering concerns for each.

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