Steel Portal Frame -Etabs

[Ahmed A. Alamin]

I'm Anyone knows how to model portal feame sheathing in Etabs for the purpose of only transfering gravity loading yo purlins, and wind loads "without contributing to frame stiffness. also, how to model partial fixity at column-base connection ; how to add tapered sections or haunches; can i design purlins in Etabs "Cold-Formed section"....Thanks

 

[Agent666]

You can reduce the shear stiffness of the sheathing. Though generally I'm more of a fan of just applying the equivalent load to the members rather than using area elements. You used to be able to use a null area (property set to 'none') as a means of distributing loads.

Put a rotational or translational spring at the supports to model partial fixity.

Define the start and end section of your haunch, then add a non-prismatic section. Set the variation in moment of inertia to suit your configuration.

Regarding purlin design, probably. Review the manual to ensure you understand any limitations.