Javad TRIUMPH-LS, User Manual

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Stake Out Alignments
Now tap “
Esc
” to return to editing horizontal align-
ment. Tap “
New Section
” to add a new section to
the end of the alignment. Note that the joint is kept
smooth - new section is still a zero-length straight
line, but directed at 18°, that is continuing the previ-
ous section. Tap the “
Straight Line
” button at the top
to change section type. We need a transition spiral to
gradually change road curvature, and type is changed
as “ Straight ” → “ Arc ” → “ Spiral ”, so tap the type button
(now changed to “
Circular Arc
”) once more to set it
to “ Transition Spiral ”. The screen now looks as shown
in Figure 13:
Figure 13
The “ Start Direction ” field still shows 18° — we do not
need to change this, as we are creating smooth curve.
The “
Spiral Type
” switch actually defines, which of the
spiral’s ends has zero curvature (infinite curvature ra-
dius):
• TC
- “ Tangent to Curve ” transition: Start Radius is
infinite, End Radius is arbitrary finite value
•
CC - “ Curve to Curve ” transition (for connecting two
arcs of different curvatures): both radii are finite
values
•
CT - “ Curve to Tangent ” transition: Start Radius is
finite, End Radius is infinite
When the section is first created, the “
Spiral Type
” is
initially set according to the curvature of the previous
section - TC if the spiral comes after straight line, and
CT
if it comes after an arc.
Now we need a 50 m transition curve for right turn
with 150 m radius, so enter the corresponding values
in “
Length
” and “
End Radius
” fields. Option for right
turn direction is checked by default (Figure 14).
Figure 14
Note that you can use the four navigation buttons
at the bottom of the screen (acting the same way on
editing screens of all four alignment components) to
move between already entered sections: