Good day,
Can STAAD pro be used to account for the additional stiffness and strength provide to steel columns from the concrete encasement (composite column sections)? I have noticed the fire protection tab in specifications and I've read in Article 5.20.9 of the Help Contents that STAAD pro does the weight calculation of these members through the use of the self weight command, but no mention is made of the strength effects this encasement will have on the structure.
Regards
The fire proofing is not going to account for any additional stiffness.
The following wiki has suggestions on how to model encased sections
http://communities.bentley.com/products/structural/structural_analysis___design/w/structural_analysis_and_design__wiki/17821.how-can-i-define-a-steel-section-encased-in-concrete-or-a-steel-section-with-a-concrete-core-in-staad-pro
Here is something more adventurous and I think it should work. The following wiki, although on a different topic, talks about something called a Property Reduction Factor. You may use factors greater than 1 to artificially jack up the stiffness of the members to account for the additional stiffness due to the casing
http://communities.bentley.com/products/structural/structural_analysis___design/w/structural_analysis_and_design__wiki/21656.accounting-for-cracked-concrete-section