Compression Members). This guidance, applied to columns built-up with cold-formed steel studs or

individual structural tubing members, is summarized in Appendix C (Paragraph C13). Columns shall be

designed such that their design strength, P (Equation C-35) exceeds the total axial applied load, Pvumax.

c. Column Bending Load and Composite Behavior. The column anchor design provisions

developed later in this guidance will create a moment connection. The primary purpose of the anchor

design is to resist shear and uplift forces. However, this anchor design will also allow the columns to act

as a moment frame, providing limited structural redundancy and widening of the hysteretic load deflection

envelopes of the shear panel. This will allow the panels to absorb more energy under cyclic seismic

loading conditions. The columns built-up from studs must be designed to act as a composite cross

section in order to provide this moment capacity. This will require welding between the studs that will

provide the shear transfer needed to develop the maximum moment in the columns. When one diagonal

strap is in tension, the full gravity load on the shear panel may be carried in a single column, with the

other column having no axial load. The maximum moment in a column will occur when it has no axial

load. Therefore the welds shall be designed for the full moment capacity of the columns. This design

requirement will allow the shear panel columns to continue providing bending resistance beyond the

lateral yield deflection of the columns. These welds shall resist the maximum shear between the studs,

which will be between the studs closest to the column neutral axis. This shear, q is defined as follows:

Vc Q

q=

(Eq 3-6)

Ic

Where:

Vc = the maximum column shear due to column moment only.

Q = the moment of the column cross-sectional area on one side of the critical weld about the

critical weld plane.

Ic = the moment of inertia of the column due to bending in the plane of the shear panel.

The maximum column shear, Vc due to the maximum column moment Mc only is determined as

follows:

2Mc 2FcyIc

Vc =

=

(Eq 3-7)

H

Hc

Where:

H = the panel height

Fcy = the yield strength of the column. This strength is not increased for column material

overstrength because weld failure is controlled by the column material strength, so that any

material overstrength would result in a proportionately greater weld strength.

c = the distance to the column neutral axis to the extreme fiber in the plane of the shear panel.

The moment of the column cross-sectional area on one side of the critical weld about the critical weld

plane, Q is defined as follows:

Q = ∫ ydA = Ay

(Eq 3-8)

A

Where:

A = the area of column cross-section on one side of the critical weld plane closest to the column

neutral axis.

critical weld plane to the critical weld failure plane.

3-7

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