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25. ROUTE SURVEYING
The coordinates of the center peg and width pegs on a parabola can be found
from the coordinates of the reference point and curve properties.
It is then possible to proceed with the setting-out of the center peg and width pegs
• Select a calculation menu depending on the section of the parabola to be
calculated.
• Parabola is calculated by the following formula.
Abbreviations used in parabola calculation
BTC:
Beginning of transition curve
BCC:
Beginning of circular curve
ETC:
End of transition curve
ECC:
End of circular curve
Calculation using BTC Point as reference:
"BTC
BCC Calculation 1"
25.5 Parabola
y
x3
6RX
------------
=
BTC
IP
Q
BP
Offset
Stationing
chainage
AZ