Roof Truss - Geometry

You can define geometry of a roof truss.

To begin defining a truss, open the Parametric Structures – Truss dialog from:

• Menu: Steel > Parametric structures > Roof truss
• Ribbon: ASD - Model > Parametric structures > Roof truss
• Toolbar: Parametric structures > Roof truss .

In the drawing area, click to specify the left and the right support points of the truss.

Six groups of bars can be distinguished in a truss (see the drawing below):

• Lower chord
• Upper chord
• Extreme diagonals
• Remaining diagonals
• Extreme verticals
• Remaining verticals

Note: The number of extreme verticals and extreme diagonals is user-defined on the appropriate tabs of the dialog.

Define profiles for the bars of a truss:

• Upper chord: I-section, T-section, rectangular pipe, round pipe
• Lower chord: all profiles listed for upper chord, and C-section positioned horizontally (rotated)
• Diagonals and verticals: angle, C-section, I-section, T-section, rectangular pipe, round pipe

The options provided in the above dialog enable definition of geometry of a plane truss.

Under Roof variant, there are 4 truss shapes available (see the drawing below):

1. Rectangular
2. Triangular
3. Bi-trapezoidal
4. Bi-trapezoidal - truncated

Under Truss geometry, specify geometric parameters for the truss types (see the drawing below):

• Truss height h
• Height d (at the support points for the third and fourth shape types)
• Number of truss fields

Truss length L results from the positions of the defined support nodes of a truss.

The specified dimensions are truss dimensions measured to axis.

After you finish defining truss dimensions, click the Chords tab to display the Truss - chords dialog.