30 November 1998
The shear panel design strength, φQsy must be greater than the seismic story shear, Vx and additional
shear force due to torsion, Qsi for all shear panels resisting in the frame of the building for which these
forces are applied. This is expressed as:
= φt ∑ nsbs t sFsy
≥ Vx + Qsi
H + W
The number of shear panels, panel width, height, and strap size and strength shall be designed
according to Equation C-34 to meet minimum lateral yield capacity. All diagonal strap material must be
ASTM A653 steel. Diagonal straps may not use re-rolled steel, because the re-rolling strain hardens the
material, increasing material strength variability and reducing elongation (see USACERL TR FL-XX,
Chapter 4 for a discussion of this concern).
C13. COLUMN AXIAL CAPACITY. The column axial design strength, P shall be determined as follows
for columns built-up with cold-formed steel studs or individual structural tubing members (AISI, C4,
Concentrically Loaded Compression Members):
P = φc A eFn
φ = the resistance factor for compression, which equals 0.85.
Ae = the effective area at the stress Fn.
Fn = the nominal strength of the column, determined as follows:
For λ ≤ 1.5
Fn = (0.658 λc )Fcy
For λc > 1.5
Fn = 2 Fcy
Fcy = the column design yield strength.
(KL r )
K = the effective length factor.
L = the unbraced length of the column.
r = the radius of gyration of the full, unreduced column cross section, calculated as follows: