2.0

Drawing Templates
271
Drawing Normal and Subgrade - Symmetrical
and Asymmetrical Template Surfaces
When drawing the template surfaces, you must consider whether the surfaces
are normal or subgrade. In addition, you must consider whether the template is
symmetrical or asymmetrical.
The following illustration shows symmetrical and asymmetrical templates:
Symmetrical and asymmetrical templates
A typical template may be made up of normal surfaces, subgrade surfaces, or a
combination of both. You can draw these surfaces symmetrically or
asymmetrically, which affects how you define the templates later on. Normal
surfaces are the elements of the template that make up the main part of the
template such as pavement surfaces, median islands, shoulders and curbs. A
typical subgrade surface is made up of granular substances, such as gravel.
The following list contains tips to keep in mind when drawing normal and
subgrade templates:
n
Both types of surfaces must be drawn with either the Draw Template
command or the PLINE command.
n
There is no limit to the number of normal surfaces on a template.
n
You can only draw one subgrade surface, but it may be composed of multiple
layers of material. Each of the subsequent subgrades are defined by their
depth below the upper subgrade and their grade to the intersecting slope.
n
When normal and subgrade surfaces are both used for a template, the
subgrade surface must be drawn below the normal surfaces.
n
When drawing the template, you only draw the top part of the subgrade
surface. When using symmetrical templates, draw this subgrade surface along
the bottom of the normal surfaces starting from the center of the template
out to the connection point out. When using asymmetrical templates, draw
from connection point to connection point.
Subgrade surfaces are linked to the normal surfaces, but use separate design
parameters, which you enter when you define the template. Entering these
parameters as numeric values creates dynamic regions that will be automatically
adjusted by the program in transitioning and superelevation conditions. You
can also control the subgrade depth by using a profile definition.