In RFEM, the member length corresponds to the distance between the two end nodes. This means that profile connections or secondary beams are only represented approximately in the model. Member eccentricities make it possible to connect members offset from the center via specific member end sections. In frames with large column sections, the beam end moments are thus reduced. Member eccentricities are taken into account by a transformation of the degrees of freedom in the local element stiffness matrix.
You can check the member eccentricities in the display modes 'Full Model'
and 'Transparent Model'
.
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Eccentricity Type
You can define the member eccentricity relative to other objects or in absolute values.
Absolute Coordinates
If the eccentricity type is not defined as 'Relative to Cross-Section', you can specify the offsets in this section (see Figure Select Eccentricity Type). The local axis system xyz, the global coordinate system XYZ, or a user-defined axis system UVW are available as reference systems.
Cross-Section Arrangement
Use the check boxes to specify at which point of the cross-section the eccentricity should be applied. The cross-section is shifted by this distance from the centroid at the node.
If you select the point in the middle of the top flange as shown in Figure New Member Eccentricity, for example, a beam member is connected flush with its top edge to a column.
Options
Transverse Offset
A transverse offset arranges the member at a certain distance from the cross-section of another member or the thickness of an adjacent surface. After activating the check box, you can define the parameters in the section Transverse Offset.
Axial Offset of Adjacent Member
An axial offset is suitable, for example, for connecting a beam member eccentrically to the flange of a column. The distance is determined from the cross-section geometry of the adjacent member. The dialog graphic illustrates the effect of the check box.
Position of the Hinge at Node
If there is a hinge at the member end, you can influence the position of this hinge with the check box: If the check box is not selected, the hinge is assumed at the shifted, eccentric member end. If the check box is selected, the hinge is located directly at the node.
Transverse Offset
Specify in the list from which 'Object' – a member or a surface – the distance is to be determined. Then enter the number of the member or surface, or select the object graphically with the
button.
Specify the 'Axis Offset' using the check boxes: This point of the cross-section or surface determines the distance of the member from the object.
