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 (b) If the V/Vp ratio on negative yield lines is less than
0.67, the plastic design moment for plates, given by Equation (84), is:
Mp = FdyZ
(c) If V/Vp is greater than 0.67, then the influence of
shear on the available moment capacity must be accounted for by means of
Equation (97).
4.
COLD-FORMED STEEL ELEMENTS.
a. Beam Elements. Many of the design provisions made for hot-rolled
shapes are equally applicable to cold-formed elements. However, the
differences in behavior under load between the two types of elements are
sufficiently pronounced to necessitate corresponding differences in design
methods. Design procedures are presented in the Specification for the
Design of Cold-Formed Steel Structural Members issued by the American Iron
and Steel Institute at Part I of its Cold-Formed Steel Manual. The
provisions for hot-rolled beam elements outlined in paragraph 3.a. of this
section are also applicable to cold-formed elements. A dynamic increase
factor of 1.1 should also be applied to the yield stress of the material.
b.
Panels.
(1) Resistance in Flexure.
For design purposes, the following
formulas are recommended:
1.
Simply-supported, single-span panel:
EQUATION:
ru = 8Mup/L2
(98)
2. Simply-fixed, single-span panel or first span of a
equally spaced continuous panel:
EQUATION:
ru = 4(Mun + 2Mup)/L2
(99)
where,
ru = resistance per unit area of panel
Mup,
Mun = positive and negative plastic moments per unit width,
respectively.
L = span length, ft
The equivalent elastic deflection, XE, is defined as
EQUATION:
XE = ([beta]ruL4)/EI
(100)
2.08-137
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