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VERAT v8i

Major option VERAT is used for the design of vertical alignments by specifying a series of intersecting straights and associated curves.  VERAT amends the vertical component for all or part of an existing master alignment string.  Therefore a master string must exist prior to applying this option.

The vertical alignment is specified by a series of vertical point intersections forming longitudinal grades.  A parameter to define the vertical curve links these grades.  Vertical curvature is parabolic.

This option is not interactive, commands must be compiled in an MX Input File.  An example VERAT input file is included at the end of this page for reference.  The following describes VERAT.

VERAT format

VERAT has no exclusive minor options; instead it uses a series of records as follows:

  • Major Option  1 record
  • Initial data  1 record

  • Element data  2 or more records

  • Final record  1 record

Each VERAT data record contains associated data fields, these fields are delineated by commas.  Comments and blank lines cannot be included within VERAT data.


Curve Definition

Vertical curves may be defined by length, M value (default) or Radius (of the vertex). Length is the most commonly used option. The relationship between M value and the more commonly used K value is M = 100 / K where K = Curve Length / Algebraic Change in Grade. Code a positive M value (or R value) for sag vertical curves, a negative M value (or R value) for crest vertical curves

Major Option Record

Major option VERAT has two associated model fields:

Model 1  Model containing the master alignment string.

Model 2  Model containing the geometry string.  If omitted, then the geometry string will not get updated.  If the master alignment and the geometry string are in the same model, then code the second model the same as the first.

Initial Data Record*
  • Field 1, Existing master string name (required)

  • Field 2, Start station of application

  • Field 3, End station of application

  • Field 4, Minimum curve length
  • Field 5, Maximum M value - Crest

  • Field 6, Maximum M value - Sag

  • Field 7, Number of intersection points (required)

  • Field 8, Curve definition (1 for M,  2 for Radius) 

*see Command Language Reference for greater detail

Element Data Record, First point of intersection

  • Field 1, Station (required)

  • Field 2, Elevation (required)

End point of intersections do not define the extent of application, back tangents are extended or truncated to the limits described on the Initial Data record.  There is only one first point of intersection.

Element Data Record, Intermediate points of intersection

  • Field 1, Station (required)

  • Field 2, Elevation (required)

  • Field 3, Curve length*

  • Field 4, M value or Radius (code a negative M value for crest vertical curves)*

*use either field 3 or 4.  Curve length is the most commonly used option.

Element Data Record, Last point of intersection

  • Field 1, Station (required)

  • Field 2, Elevation (required)

Similar to the first point of intersection, the last point of an intersection does not define the extent of application, ahead tangents are extended or truncated to the limits described on the Initial Data record.  There is only one last point of intersection.

Final Record

The data should be terminated by the global minor option 999.


Example VERAT Input File

MOSS
VERAT,PALIGN,PALIGN
MCAM,11150,12100,7=4,2
11150,767.8
11505,765.1,150
11940,768.8,600
12100,764.7
999
FINISH

All MX input files should begin with MOSS and end with FINISH.





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