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Chapter 4 Working with Cross Sections
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Creating Cross Sections
Use the commands in the Cross Sections menu to design a roadway in cross
section view. Cross sections are cut along the horizontal (plan) alignment at
station intervals. The cross section X, Y, and Z coordinates are obtained from
the horizontal alignment, the profile elevations, and the sampled surface. A
completed cross section is composed of existing ground surfaces, a finished
ground template, slopes, and optional ditches.
You begin creating cross sections by sampling the existing ground surface along
a horizontal alignment. You can then edit existing ground cross sections using
the Edit Sections command.
To create finished ground cross sections, you design and apply a roadway
template. This represents the chosen design of a road, showing the lane and
shoulder widths, ditches, foreslopes, and backslopes in a cross sectional view.
Templates are defined from polyline surfaces.
Next, define slope and ditch settings, and then apply superelevation. The slope,
superelevation, template, ditch, and transition attachment settings are referred
to as Design Control and are located in the Design Control submenu.
For a more detailed list that describes the process of creating cross sections, see
The Process of Creating Cross Sections in this chapter.
Many variables affect how cross sections are created and updated. For a list of
actions that affect cross section design control, see Actions that Affect Cross
Section Control in this chapter.
Prerequisites: Before working with cross sections, you must define the
centerline alignment using the Horizontal Alignment commands create the
existing ground profile, and define the finished ground centerline profile.
NOTE
You can create the existing ground cross sections before the profile, but if
you want to apply the design templates to the cross sections, you must
create the profiles first.
The Process of Creating Cross Sections
The following steps describe the process of completing the cross section design
for an alignment:
1 Create Existing Ground Data: You can create the existing ground data for cross
sections in one of three ways. You can sample the data from one or more
surfaces, you can import the data from a text file, or you can enter the data into
the Existing Ground Section Editor.
2 Create Existing Ground Subsurfaces (optional): There are two methods you
can use to create existing ground subsurfaces. You can create them at the same
time as the top surface by sampling multiple surfaces or by sampling them from
a text file. Alternately, if you create the cross sections from a single existing
surface, then you can define the subsurfaces later by entering borehole data
with Interpolation Control in the Existing Ground Editor.
3 Draw and Define Templates: A template represents the finished ground
surfaces, such as the asphalt and granular surfaces, and may contain predefined
subassemblies for curb and shoulder surfaces. There are two types of templates.