Click the Stiffeners tab in the Detailed analysis (steel member design) dialog to display the following dialog:
Once the Detailed analysis is run, ribs are introduced automatically at the following points along a member:
- At the points where supports are defined
- At the points where concentrated loads are applied
- At the points where adjoining bars are identified
- If the distances between bracings are excessive and do not meet code-defined requirements.
It is possible to modify the parameters of the automatically-defined ribs which can also be added or deleted.
The following rib parameters are set by default:
- Rib type - bilateral
- Thickness = web thickness
- Height = web height
- Position - top.
By default, the beam length equals the distance between the theoretical axes of members. You can set the actual dimensions of the beam by means of the parameters: Shift a or Shift b. If a value is introduced into theShift afield, the beam beginning will be shifted, while the introduction of a value into theShift bfield results in shifting the beam end. For instance, if one types the value of shift a = -0.2 m, the beam beginning will be shifted to the left (the beam will be lengthened), while typing b=0.2 results in lengthening the beam by shifting its end to the right.
You can also define the buckling length coefficient for the rib in question (Beta_s option). It is possible to select the most frequently used coefficients from the list or to define a new value of the coefficient.