### Straight inclined road on a terrain

The subgrade of a straight road has the width 10m and inclination from point A (with the elevation 30) to the point B with the slope of 4%. On the given terrain solve the earthwork for building this road.

**1st solution - elevated projection**

template

Steps of the construction:

Determine the boundary line of the subgrade, grade the axis AB and construct the horizontals of the subgrade (interval of the subgrade plane is 25m).
The given position of the subgrade and topographical surface, i.e. the given horizontals on the template are not enough for determining the neutral line. Therefore, the horizontals with the elevation 31 and 33 are drawn, and afterwards the ones with the elevation 30.75 and 32.5, as well as the ones with the elevation 30.625 and 32.75 on the subgrade and on the terrain.
Construct the horizontal of the fills with the elevation 30, its scales of slope, remaining horizontals and determine the intersection of the fills and terrain.
Construct the horizontal on the cuts with the elevation 30, its scales of slope, remaining horizontals and determine the intersection of the cuts and terrain.

**2nd solution - program Rhino**

construction of the subgrade, neutral line and fills

construction of the cuts and final image

the elevated projection for print

### Inclined road on a circular arc

Within this course we will not solve tasks with inclined roads on a circular arc.

These surfaces have to be approximated with special surfaces that are called **helical surfaces**.

Students interested in this subject can find some materials on the following site. These are the materials for the elective course Perspective which is held on the graduate studies.

Helix, helical surface and its application for constructing inclined road on a circular arc.

Created by Sonja Gorjanc, translated by Helena Halas and Iva Kodrnja - 3DGeomTeh - Developing project of the University of Zagreb