CEMP-E
TI 809-07
30 November 1998
The shear panel design strength, φQsy must be greater than the seismic story shear, Vx and additional
t
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:
W
= φt ∑ nsbs t sFsy
≥ Vx + Qsi
φtQsy
(Eq C-34)
2
H + W
2
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
(Eq C-35)
Where:
φ = the resistance factor for compression, which equals 0.85.
c
Ae = the effective area at the stress Fn.
Fn = the nominal strength of the column, determined as follows:
For λ ≤ 1.5
c
2
Fn = (0.658 λc )Fcy
(Eq C-36)
For λc > 1.5
0.877
Fn = 2 Fcy
(Eq C-37)
λc
Where:
Fcy
λc =
(Eq C-38)
Fe
Where:
Fcy = the column design yield strength.
π2E
Fe =
(Eq C-39)
(KL r )
2
Where:
E = the modulus of elasticity.
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:
C-10
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