Figure 10-3.—Storm sewer plan and profile.
understanding of horizontal and vertical curves. Those
cross-sectional areas) and then multiply that average-
will be discussed in the next chapter.
Earthwork Computations
Computing earthwork volumes is a necessary
activity for nearly all construction projects and is often
accomplished as a part of route surveying, especially
for roads and highways. Suppose, for example, that a
volume of cut must be removed between two adjacent
stations along a highway route. If the area of the
cross section at each station is known, you can
compute the average-end area (the average of the two
end area by the known horizontal distance between the
stations to determine the volume of cut.
To determine the area of a cross section easily, you
can run a planimeter around the plotted outline of the
section. Counting the squares, explained in chapter 7
of this traman, is another way to determine the area of
a cross section. Three other methods are explained
below.
AREA BY RESOLUTION.— Any regular or
irregular polygon can be resolved into easily
calculable geometric figures, such as triangles and
10-7
