Table 1: Design criteria for steel CBF-V structures according to NTC08.

Bracing Class sections 1 or 2; for circular hollow sections: d/t ≤ 36
q-factor Ductility Class High 2.5
Low 2
where: d and t are diameter and thickness of the circular hollow profile, respectively; NEd is the brace design axial force; Npl,Rd is the brace plastic resistance; Nb,Rd is the brace buckling resistance; is the brace normalized slenderness; Ω is the over-strength factor; γRd is the steel over-strength factor that is the ratio between the average and the characteristic values of the yielding strength; γpb is a factor representative of the residual brace strength after buckling; NEdG is the axial force corresponding to non-seismic loads and NEdE is the axial force corresponding to seismic loads.