Truss member (Geometry)

Truss member property	Description
Icon
Modules where available
Function	It models bars with limited compression and tension-only bars like cables, pull rods, diagonal braces etc.
Axis position	Arbitrary (horizontal, vertical and skew)
Geometry	Straight
Cross-section	Arbitrary profile
Connection	Always hinged (cannot be modified) It can be connected to other elements only at its ends It does not intersect other elements cross it visually
Material	Steel, concrete, timber and general
Load direction	Axial
Load type	Dead load (will be distributed to the end nodes) Uniform line temperature variation Shrinkage Line stress load Point mass (will be distributed to the end nodes)
Analysis	Displacement, normal force and stress
Available design	Steel design in
	RC design in
	Timber design in
Alternative	Steel truss member can be modeled/designed as the set of shells (Shell model)
Default Short Command	TR

Table: Truss member properties

Figure: Modeling a truss

Definition steps

1. If needed (and available in the current FEM-Design module), set a proper position for the working plane. In the 3D design modules, respect that the gravity direction is always the Global Z axis direction.
2. Start  Truss member command from  tabmenu and choose  Define.
   
3. Set the properties of the new truss element at  Default settings:
   • Identifier (General)
     The program automatically generates it, but you can define custom value. Identifier (ID and Position) number can be displayed in model view (Display settings).
   • Non-linear behaviour (General)
     Limited capacity and Brittle/Plastic can be set for both compression and tension. These options are considered only for load combinations calculated as non-linear elastic. Plastic behaviour is only considered for load combinations calculated as non-linear elastic + plastic.
   • Section
     Choose a profile from the Section library or define a new cross-section by parameters. The applied section name can be displayed in model view (Display settings).
   • Material
     Any type of materials can be set for beam Analysis, but design can be run for concrete, steel and timber elements only. The applied material name can be displayed in model view (Display settings).
4. Define the direction of the cross-section y’ axis.
5. Choose a geometry definition method for the truss element reference line (axis).
6. Define the element in the model view based on the chosen geometry method.

Optional steps:

7. Modify the bar properties with the  Properties tool of the Truss member tool palette.
8. Set the display settings of truss elements at Settings > All > Display > Beam, Column and Truss similarly to Beams.
9. The truss elements are stored on “Truss members” Object layers. At layer settings, the default color and pen width can be set for all truss elements. The color and pen width settings by selected truss elements can be modified by Edit > Properties > Change appearance.