Pavement Stakeout
Pavement stakeout will depend on the type of
paving equipment used. Steps in the method
commonly used for paving concrete highways are
as follows:
1. Set a double line of steel side forms,
equipped with flanges that serve as tracts for
traveling paving equipment.
2. Fill the space between the forms with
concrete poured from a concrete paving machine
(commonly called just a paver).
3. Spread the’ concrete with a mechanical
spreader that travels on the flanges of the side forms.
4. Finish the surface with a finisher, a
machine that also travels on the side forms.
The line-and-grade problem—that is, the
layout or stakeout problem—consists principally
of setting the side forms to correct line with the
upper edges of the flanges at the grade prescribed
for the highway. If the finished grade shown on
the plans is the center-line grade, then the forms
are set with tops at the center-line grade less the
crossfall. If the design elevations are shown for
points other than those on the center line, the
form elevation is related to the design points as
indicated by the typical section.
Stakeout maybe done by setting a line or lines
of offset hubs, as previously described. Some-
times, however, a line of hubs is driven along the
line the forms will occupy and driven to grade
elevation less the depth of a side form. The forms
are then set to the line and the grade by simply
placing them on the hubs.
Concrete paving is also done by the slip form
method in which, instead of a complete double
line of forms, a sliding or traveling section of
formwork is an integral part of the spreading and
finishing machinery. The machinery is kept on line
and the pavement finished at grade by a control
device or devices. The line control device usually
follows a wire stretched between rods that are
offset from the pavement edge.
Forms are not usually used in asphalt paving.
Asphalt paving equipment, in general, is designed
to lay the pavement at a given thickness, following
the fine-graded subgrade surface. The manner in
which a given piece of equipment is kept on line
varies, and the stakeout for equipment varies
accordingly.
STRUCTURAL SURVEYS
A STRUCTURAL survey is one that is part
of the chain of human activities that will bring
a structure, such as a building, a bridge, or a pier
into existence.
Earthwork
As when a highway is built, the first major
step in the construction of a structure is usually
the rough grading—that is, the earthmoving
needed to bring the surface of the site up to, or
down to, the approximate specified rough grade.
The stakeout for rough grading is commonly
done by the GRID method. The area to be graded,
which is shown, along with the prescribed finish
grade elevation on the site or plot plan is laid off
in 25-, 50-, or 100-ft grid squares. The elevation
at each corner point is determined; the difference
between that and the prescribed grade elevation
is computed; and a grade stake is marked with
the depth of cut or fill; then the stake is driven
into the ground at the point.
Building Stakeout
If the structure is a building, the next major
step after the rough grading is the building
stakeout; that is, the locating and staking of the
main horizontal control points of the building.
These are usually the principal corner points plus
any other points of intersection between building
lines.
The procedure followed varies with circum-
stances. Figure 14-39 shows a simple building
Figure 14-39.-Building stakeout.
14-41
