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Table Of Contents
Chapter 3 Working with Profiles and Vertical Alignments
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Creating Ditches and Transitions
The main difference between the Ditches and Transitions (DT) command and
the finished ground centerline (FGC) commands is the first prompt. The first
prompt of most ditches and transitions commands asks for which vertical
alignment you want to use. This prompt is generally in the following format:
Select profile (Center/Left/Right)<Center>: R
Select right profile (Ditch/1/2/3/4/5/6/7/8)<1>:
If you press ENTER at the first prompt above, then you can open the finished
ground centerline profile. If you type L or R, then you have the choice of which
ditch or transition to open. In the example above, the 1 through 8 alignments
are the eight offsets available on the right side of the centerline. These
alignments are generally used to control the location of key points on cross
section templates, such as the right edge of pavement (EOP) and shoulder. The
1 through 8 alignments are also available for the left side of centerline. You can
access the left and right ditch profiles by entering the appropriate offset side,
and then entering a D for ditch.
NOTE
You can also use AutoCAD commands to draw tangents, but you must use
the DT Vertical Curves command to create vertical curves.
After you design ditches and transitions, you can apply them to the templates
used in cross section design.
Working with Vertical Alignment Tangents for
the Ditches and Transitions
You can draw vertical alignment tangents for ditches and transitions using the
DT Tangents commands on the Profile menu. With these commands, you can
set the current layer, rotate the AutoCAD crosshairs to match the grade of the
ditches and transitions, draw vertical alignment tangents, change the grade
going into and coming out of the ditches and transitions, and move the point
of vertical intersection.
Setting the Current Layer for the Ditches and
Transitions
To set the current layer for ditches and transitions
1 From the Profiles menu, choose DT Tangents ä Set Current Layer.
2 Choose one of the following options:
n
Type C for the centerline.
n
Type L or R for the Left or Right ditch/transition regions. If you choose Left
or Right at the Select profile prompt, the next prompt asks you to select the
type of profile you want to set as current.