Member Orientation

To allow the analytic and physical members in a model to reflect the orientation of the real structural elements comprising the structure to be modelled, MasterFrame includes a member orientation angle, which represents the rotation of the angle about its local x-axis. This is termed the beta angle. To allow for the definition of this angle, MasterFrame defines a ‘top’ surface of a structural member cross section. Even sections with a circular cross section, the analytic and physical members with still have a defined top surface from which an orientation is defined. In general, for singly or doubly-symmetric steel sections, the defined ‘top’ is associated with the cross section major axis.

You can align the beta angle of member relative to another member. For example, if you had a horizontal member between two sloping rafters and you wanted the beta angle of the horizontal member to be rotated to that it is aligned with the slope of the rafter, you can hold ctrl or alt and pick the rafter member to align major or minor axis of beam with the rafter slope. A similar function has existed for some time for columns, whereby using ctrl or alt and clicking on connected beams would align the beta angle of the column with the beam.

The beta angle is utilised within the software when displaying analysis results and also within the design modules.

Doubly symmetric sections have a defined top surface. Therefore, while in reality rotating a physical entity through 180 degrees makes no difference to the structure, the software will analyse the structure according to the member orientation. Hence, in the steel design, the bending moment diagram will be reversed from what would be expected, due to the orientation of the member and direction of load. The resulting structural behaviour will not change since the stiffness of the structure would be unaltered.

The software graphical view of the model includes beta angle indicators.