3D Girder Parameters

3D girders use the full part instead of extracted cross-sections.

Parameter Description	Content Parameter	Parametric Value	InfraWorks Set/Read	Inventor	Revit
* Depth at start	Depth1	The distance from the top to the bottom of the girder at its start position.	Yes/No	No	Not applicable
* Depth at end	Depth2	The distance from the top to the bottom of the girder at its end position.	Yes/No	No	Not applicable
Left deck width at start	LeftDeckWidth1	The distance at the start of a girder between its origin and the origin of the girder to its immediate left. If the girder is the leftmost, then it is the distance between its origin and the left edge of the deck.	No/Yes	No	Not applicable
Left deck width at end	LeftDeckWidth2	The distance at the end of a girder between its origin and the origin of the girder to its immediate left. If the girder is the leftmost, then it is the distance between its origin and the left edge of the deck.	No/Yes	No	Not applicable
Left bottom slope in percentage at start	LeftBottomSlopeInPercentage1	The slope of the left bottom flange at the start position as a percentage.	No/Yes	No	Not applicable
Left bottom slope in percentage at end	LeftBottomSlopeInPercentage2	The slope of the left bottom flange at the end position as a percentage.	No/Yes	No	Not applicable
Left deck slope in percentage at start	LeftDeckSlopeInPercentage1	The slope of the deck to the left of the alignment at the start position as a percentage.	No/Yes	No	Not applicable
Left deck slope in percentage at end	LeftDeckSlopeInPercentage2	The slope of the deck to the left of the alignment at the end position as a percentage.	No/Yes	No	Not applicable
Match girder bottom slopes to deck slopes	MatchGirderBotSlopesToDeckSlopes	Determines how the bottom of a girder is laterally aligned with a deck slope. Either True or False.	Yes/No	No	Not applicable
Match girder top slopes to deck slopes	MatchGirderTopSlopesToDeckSlopes	Determines how the top of a girder is laterally aligned with a deck slope. Either True or False.	Yes/No	No	Not applicable
Right bottom slope in percentage at start	RightBottomSlopeInPercentage1	The slope of the right bottom flange at the start position as a percentage.	No/Yes	No	Not applicable
Right bottom slope in percentage at end	RightBottomSlopeInPercentage2	The slope of the right bottom flange at the end position as a percentage.	No/Yes	No	Not applicable
Right deck slope in percentage at start	RightDeckSlopeInPercentage1	The slope of the deck to the right of the alignment at the start position as a percentage.	No/Yes	No	Not applicable
Right deck slope in percentage at end	RightDeckSlopeInPercentage2	The slope of the deck to the right of the alignment at the end position as a percentage.	No/Yes	No	Not applicable
Right deck width at start	RightDeckWidth1	The distance at the start of a girder between its origin and the origin of the girder to its immediate right. If the girder is the rightmost, then it is the distance between its origin and the right edge of the deck.	No/Yes	No	Not applicable
Right deck width at end	RightDeckWidth2	The distance at the end of a girder between its origin and the origin of the girder to its immediate right. If the girder is the rightmost, then it is the distance between its origin and the right edge of the deck.	No/Yes	No	Not applicable
* Segment length	SegmentLength	The length the girder needs to be to fit between its start and end positions.	No/Yes	No	Not applicable
* Skew at start	Skew1	The horizontal skew applied at the start of a girder.	No/Yes	No	Not applicable
* Skew at end	Skew2	The horizontal skew applied at the end of a girder.	No/Yes	No	Not applicable
* Vertical slope at start	VerticalSlope1FromPerp	The vertical skew applied at the start of a girder.	No/Yes	No	Not applicable
* Vertical slope at end	VerticalSlope2FromPerp	The vertical skew applied at the end of a girder.	No/Yes	No	Not applicable

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.

3D Girder Placement

3D girder origins are defined by lateral, longitudinal, and vertical dimensions.

Lateral and Longitudinal Dimensions. The start position for a 3D girder is determined by both its start station and lateral offset along the alignment. The origin is aligned with this position. When designed, the origin of a girder must be at the start of the girder part for this reason.

Vertical Dimension. Girder origins can be at any elevation (or Y value in the coordinate system of the girder). Girders are vertically matched to the deck above, their bearings, or supports below.

3D Girder Widths

When specifying girder widths, parameters of adjacent girders share the same widths for left to right distances as seen in the image below.

3D girder width parameters

Girder Origins	RightDeckWidth1
Left Deck Edge	LeftDeckWidth1
Right Deck Edge

When a girder is the only girder supporting a deck these dimensions can make the girder the same width as the deck at girder start and end.

3D Girder Lateral Slopes

MatchGirderTopSlopesToDeckSlopes also helps determine how a girder is laterally aligned with a deck. In the following image the girder on the left is set to True, while the girder on the right is set to false.

Slope matching example

When set to True, The lateral slope portions of the underside of the deck to the left and right of the alignment are considered. Slice dimensions are then set depending on where the lateral offset of the girder is negative, 0, or positive.

Dimension	Lateral Offset	Set to Deck Underside Slope
LeftDeckSlopeInPercentage1	Negative	Left
LeftDeckSlopeInPercentage1	0	Left
LeftDeckSlopeInPercentage1	Positive	Right
LeftDeckSlopeInPercentage2	Negative	Left
LeftDeckSlopeInPercentage2	0	Left
LeftDeckSlopeInPercentage2	Positive	Right
RightDeckSlopeInPercentage1	Negative	Left
RightDeckSlopeInPercentage1	0	Right
RightDeckSlopeInPercentage1	Positive	Right
RightDeckSlopeInPercentage2	Negative	Left
RightDeckSlopeInPercentage2	0	Right
RightDeckSlopeInPercentage2	Positive	Right

If a girder is to the left or right of the alignment, the entire top can be sloped to match the deck left or right slope.

Similarly, when MatchGirderBotSlopesToDeckSlopes is True, LeftBotFlangeSlopeInPercentage1, LeftBotFlangeSlopeInPercentage2, RightBotFlangeSlopeInPercentage1, and RightBotFlangeSlopeInPercentage2 are set in the same manner as the top slopes.

Note: If MatchGirderTopSlopesToDeckSlopes is False, then MatchGirderBotSlopesToDeckSlopes is treated as False, regardless of its value.

End Angle Skewing

For a proper fit with other bridge features, girder start and end faces must skew horizontally to align with the support (which may also be skewed). It must also skew vertically to be perpendicular to the alignment. These angles are calculated and converted to the coordinate system of the girder using Skew1, Skew2, VerticalSlope1FromPerp, and VerticalSlope2FromPerp.