developed from the original plan and profile sheet of
a typical road project. They depict different earthwork
phases to be considered by the EO when engaged in
earthmoving operations.
The sketches shown in figures 15-12 and 15-13
were prepared by placing a piece of tracing paper
directly over the plan and profile sheet and tracing the
new road and stations. Information was added that was
not included on the original plan and profile sheet,
such as borrow pit, waste pit, stream, temporary haul
road, temporary culverts, equipment area, planned
cut-and-fill areas, and a typical road section. Any
information may be included that allows you to
visualize the finished product.
EARTHWORK COMPUTATIONS
Earthwork computations are the calculations of
earthwork volumes or quantities to determine final
grades, to balance cut and fill, and to PLAN the most
economical movement of material.
Volume Changes
Most earthmoving is computed in cubic yards;
however, on some project drawings, the metric system
is used. A cubic yard is a cube 3 feet long, 3 feet wide,
and 3 feet high. Many dimensions in field
measurements and contract plans are in feet, so if they
are multiplied together to obtain bulk (length x width
x depth), the results are in cubic feet. To obtain cubic
yards from cubic feet, divide the cubic feet by 27
(there are 27 cubic feet in one cubic yard). It is also
possible to divide the original linear measurement by
3 to convert the numbers to into yards, and then
multiply. However, this may lead to working in
fractions, decimals, and mixed numbers.
Cubic yards of material are either in place, loose,
or compacted. Material, excavated from its natural
state, increases in volume, commonly known as swell.
Undisturbed material is measured as in-place cubic
yards, material loosen by handling is measured in
loose cubic yards, and the volume of compacted
material is measured as compacted cubic yards.
NOTE: When calculating estimates from project
drawings, you estimate cuts as in-place cubic yards
and estimate fills as compacted cubic yards.
To calculate the correct amount of material to be
handled, you convert the present soil conditions by
using table 15-1.
Road Nomenclature
A cross-sectional view of a road and its
components is shown in figure 15-14. Before any
construction is performed on a project site, the
elevation is known as existing grade. The driving
Figure 15-14.—Road nomenclature.
15-10
