A member type controls member stiffnesses and properties applied in the structural analysis. The most common member type is a beam: This bending-resistant member can transfer all internal forces.
Beam
A beam is a bending-resistant member that can transfer all internal forces. If there are two beams connected to each other and no release has been defined for the common node, the connection is bending-resistant.
Rigid Member
A rigid member couples the displacements of two nodes by means of a rigid connection. In principle, it corresponds to a coupling member, but its hinges can be assigned individually at the member ends.
The following stiffnesses are used in the calculation:
- Longitudinal and torsional stiffness: E ⋅ A = G ⋅ IT = 1013 ⋅ ℓ
- Flexural resistance: E ⋅ I = 1013 ⋅ ℓ3
- Shear stiffness: GAy = GAz = 1016 ⋅ ℓ3, where ℓ is the member length in [SI unit]
Rib
A rib allows you to define a downstand or an upstand beam with effective slab widths. Within the effective slab widths, the slab internal forces are integrated and added to the member internal forces.
Truss
A truss member is a beam member with hinges arranged at the member ends that transfer no moments.
Truss (only N)
A truss member (only N) has only one longitudinal stiffness E ⋅ A. Moment hinges are arranged at the member ends.
Tension / Compression
A tension member is a truss member (only N) with the additional property of absorbing tensile forces only. Accordingly, a compression member only transfers compressive forces.
Buckling
A buckling member is a truss (only N) with the additional property of failing under a compressive force that exceeds the buckling force Ncr.
Cable
Cables only absorb tension forces. Through iterative calculation and consideration of the cable theory (large deformation analysis), this allows the determination of cable chains with longitudinal and transverse forces.
Cable on Pulleys
A cable on pulleys can only absorb tensile forces and has only one possible displacement of the inner nodes in the longitudinal direction ux. This member type is calculated according to the cable theory (large deformation analysis) and is suitable for the calculation of pulley block systems on which the longitudinal forces are transmitted by a pulley.
Result Beam
A result beam has no stiffness and has no influence on the structural analysis. The result beam is a tool for integrating surface, solid, or member results in a predefined area for the subsequent design.
Joist
A virtual beam allows you to apply the cross-section properties for "Open Web Steel Joists" that the Steel Joist Institute has defined in "Virtual Joist" tables.
Stiffness
The member type "Definable Stiffness" makes it possible to specify user-defined stiffnesses for structural analysis.
Coupling
A coupling member has the stiffness of a rigid member. Furthermore, the degrees of freedom of the start and end nodes are defined for the coupling member, depending on the specification. The following coupling members are available:
- Coupling Rigid-Rigid: a rigid connection of the coupling member on both sides
- Coupling Rigid-Hinge: a rigid connection at the start, a hinged connection at the end of the member
- Coupling Hinge-Hinge: a hinged connection of the coupling member on both sides
- Coupling Hinge-Rigid: a hinged connection at the start, a rigid connection at the end of the member
Spring
A spring allows you to specify a spring stiffness for a member.
Damper
In principle, a damper corresponds to a spring member with the additional property "Damping coefficient". This member type extends the possibilities for dynamic analyses according to the time history analysis.