Universal Abutment Parameters

The following parameter values are applicable to all abutment parts. Dimension sets determine the location and positioning of the abutment.

Longitudinal Placement

The following universal parameters position an abutment along a road alignment.

Parameter Description	Content Parameter	Parametric Value	InfraWorks Set/Read	Inventor	Revit
Origin to back of ballast wall	OriginToBBW	The distance from back of the ballast wall to the part origin. Positive is in front of the back of the ballast wall; negative is behind.	Yes/No	No	Yes
Ballast wall height	BallastWallHeight	The distance from the bottom to the top of a ballast wall.	Yes/Yes	No	No
Ballast wall thickness	BallastWallThickness	The distance from the back to the front of a ballast wall.	Yes/No	No	Yes
* Centerline of bearing to back of ballast wall	CLBearingToBBW	The distance from the back of the ballast wall to the bearing line.	Yes/No	No	Yes
* Seat width	SeatWidth	The distance from the back of the ballast wall to the front of seat.	Yes/No	No	Yes

Note: The single asterisk "*" indicates that a parameter is a geometry parameter that is required, and has been marked as a 'key' parameter in Autodesk Inventor.

Longitudinal placement dimensions

Abutment Origin	BallastWallThickness
Bearing Line	CLBearingToBBW
SeatWidth	OriginToBBW

Longitudinal Slope

Both longitudinal slopes are currently set by InfraWorks, to the grade of the alignment over the abutment. These are not configurable.

Parameter Description	Content Parameter	Parametric Value	InfraWorks Set/Read	Inventor	Revit
Longitudinal slope	LongitudinalSlope	The angle of a ballast wall top elevation. This is positive when increasing in the forward direction of the abutment.	No/Yes	No	No
Seat longitudinal slope	SeatLongiSlope	The angle of a seat top elevation. This is positive when decreasing in the forward direction of the seat.	No/Yes	No	Yes

Longitudinal slope dimensions

LongitudinalSlope

SeatLongSlope

In the diagram, the forward direction is right to left. SeatLongiSlope is positive when the seat top elevation decreases in the forward direction.

Vertical Placement

Vertical placement parameters vertically aligns the abutment and allows for manual refinement through offsets.

Parameter Description	Content Parameter	Parametric Value	InfraWorks Set/Read	Inventor	Revit
Match by surface to bearings	MatchBySurfaceToBearings	The method for vertically aligning the abutment under deck, girders and bearings. Either True or False (see below for more information).	Yes/No	No	Yes
Ballast wall top vertical offset	BallastWallTopVerticalOffset	Adjusts the ballast wall up (positive) or down (negative) by this distance.	Yes/No	No	Yes
Vertical offset from seat top	SeatTopVerticalOffset	Adjusts the seat up (positive) or down (negative) by this distance.	Yes/Yes	No	Yes

When MatchBySurfaceToBearings is set to True, the abutment aligns with the ballast wall meshes touching the bottom of the deck and the seat meshes touching the bottoms of the bearings. This is the more precise method.

When MatchBySurfaceToBearings is set to False, 2 planes are determined: one to the left of the origin and one to the right. The ballast wall planes align to touch the deck bottom. The seat planes align to touch bearing bottoms. This method is faster but less precise.

Note: For Slope-based abutments, the origin must be at the elevation of the top front of the ballast wall, where it intersects the alignment. For Offset-based abutments, the origin must be at the elevation of the top of the seat, at the intersection of ballast wall front and alignment, plus SeatOffset.

Lateral Widths

InfraWorks calculates LeftWidth and RightWidth based on the left and right widths of its deck at the abutment, and overhangs.

Parameter Description	Content Parameter	Parametric Value	InfraWorks Set/Read	Inventor	Revit
* Left width	LeftWidth	The distance from the abutment origin to its left edge.	No/Yes	No	No
* Right width	RightWidth	The distance from the abutment origin to its right edge.	No/Yes	No	No

Note: The single asterisk "*" indicates that a parameter is a geometry parameter that is required, and has been marked as a 'key' parameter in Autodesk Inventor.

Lateral width dimensions

Deck	LeftWidth
Origin	RightWidth
Left Overhang	Right Overhang

The overhangs can laterally offset the abutment edges from the deck edges. Positive overhang values move the abutment edges outward and negative values inward.

Deck widths and the overhangs are measured perpendicular to the alignment. Abutment left and right width are measured along the abutment’s skew line. So start abutments calculate as:

LeftWidth ~= (deck_left_width + LeftOverhang) * cos(skew)
RightWidth ~= (deck_right_width + RightOverhang) * cos(skew)

For end abutments, deck left and right is opposite abutment left and right:

LeftWidth ~= (deck_right_width + LeftOverhang) * cos(skew)
RightWidth ~= (deck_left_width + RightOverhang) * cos(skew)

These equations are correct when for straight alignments but less precise for curved alignments.

Skew

Parameter Description	Content Parameter	Parametric Value	InfraWorks Set/Read	Inventor	Revit
* Skew	Skew	The angle of counterclockwise rotation of the abutment around the Z-axis of the coordinate system of the road.	Yes/No	No	No

Note: The single asterisk "*" indicates that a parameter is a geometry parameter that is required, and has been marked as a 'key' parameter in Autodesk Inventor.

Skew is passed down to parts. InfraWorks factory abutment parts use skew to keep wing walls parallel to the alignment, by shearing the part by the skew angle.