Analysis for SCBF per AISC 341-16 with ideCAD

Symbols

A_g = Gross area of member, in.² (mm²)
F_y = Specified minimum yield stress
R_y = Ratio of the expected yield stress to the specified minimum yield stress, Fy
F_cre = Critical stress calculated from Specification Chapter E using expected yield stress, ksi (MPa)
P₁ = Compressive strength
P₂ = Compressive strength for post-buckling
T = Tensile strength

The required strength of elements and connections in SCBF are determined using the capacity-limited seismic load effect. The capacity-limited horizontal seismic load effect, E_cl, is taken as the larger force determined from the following analyses:

• An analysis in which all braces are assumed to resist forces corresponding to their expected strength in compression or in tension

• An analysis in which all braces in tension are assumed to resist forces corresponding to their expected strength, and all braces in compression are assumed to resist their expected post-buckling strength.

The expected brace strength in tension is R_yF_yA_g. The expected brace strength in compression is permitted to be taken as the lesser of R_yF_yA_g and (1/0.877)F_creA_g, where F_cre is determined from Specification Chapter E using the equations for F_cr, except that the expected yield stress, R_yF_y, is used in lieu of F_y. The brace length used to determine F_cre shall not exceed the distance from the brace end to the brace end.
The expected post-buckling brace strength shall be taken as a maximum of 0.3 times the expected brace strength in compression.