CEMP-E
TI 809-07
30 November 1998
Mnx = the column gross cross-section nominal moment capacity, and this is defined as follows
(modification of AISI Equation C3.1.1-1):
Ic
h -c
= Fcy
Mnx
(Eq 3-13)
c
Where:
hc = the width of the column in the plane of the shear panel.
c = the distance from the column neutral axis to the extreme fiber.
e. Column Shear Capacity. The trial column design must be checked for shear capacity. The
diagonal straps fasten to the columns near their connection to the tracks and column anchor. Therefore
the column must either have adequate shear capacity for the maximum horizontal seismic force, Ω0QE
applied to the shear panel, or the column shear capacity must be augmented with other components.
The column shear design strength, VC shall be determined based on AISI guidance (Section C.3.2,
Strength for Shear Only). This guidance, applied to columns built-up with cold-formed steel studs or
individual structural tubing members, is summarized in Appendix C (Paragraph C14). For columns built-
up with studs, the maximum stud flange width over thickness, (h/t)max is defined as follows:
h
Ek v
= 0.96
(Eq 3-14)
t
Fcy
c
max
Where:
h = the depth of the flat portion of the column web, which equals the stud flange width.
tc= the column web thickness, which equals the stud thickness.
kv = the shear buckling coefficient, which equals 5.34.
For studs with a flange width of 50-mm (2 inches) this requires a minimum stud thickness of 0.77-mm (30
mil or 20 gauge) for 33 ksi steel and 0.95 mm (37 mil or 18 gauge) for 50 ksi steel.
Columns have insufficient shear capacity by themselves, and require additional shear capacity from their
anchorage detail (see paragraph 3.10a for anchorage shear design guidance).
9. CONNECTION DESIGN.
a. Connection Design Assumptions and Applied Loads. This paragraph provides connection design
assumptions that define loading and load path issues for cold-formed steel shear panels. These
assumptions apply to the diagonal strap-to-column connections. These loads are based only on the
maximum lateral force, Ω0QE. This force results from the right-hand term in Equation C-18, Ω0QE, which
accounts for diagonal strap material overstrength. The maximum estimated ultimate force in the diagonal
straps (in the axis of the straps), Psu, is:
Psu = Fsu max n sb s t s
(Eq 3-15)
The diagonal strap-to-column connection shall be designed to resist the force defined by Equation 3-15.
Panel design will require the use of angle section anchors as described under panel anchors (pargraph
10), because of the shear transfer requirements. This anchor will also transfer loads between the column
and base or top beam, or floor slabs, thereby eliminating the need for load transfer with a column-to-track
connection. In low seismic zones it may be possible to transfer the shear forces with a column-to-track
connection only, without anchors. However, it is considered more reasonable to use fewer shear panels
3-9
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