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 (b) The curves in Figures 43 and 44 present the variation of
Qu as a function of the web thickness for bearing lengths of 1 to 5 inches
for end and interior supports, respectively. Tables 15 through 18 present
the same variation of Qu for Fy = 60 and 80 ksi. It should be noted
that the values reported in the charts and tables relate to one web only,
the total ultimate reaction being obtained by multiplying Qu by the number
of webs in the panel.
5.
COLUMNS AND BEAM COLUMNS.
a. Plastic Design Criteria. The design criteria for columns and beam
columns must account for their behavior not only as individual members but
also as members of the overall frame structure. Depending on the nature of
the loading, several design cases may be encountered. Listed below are the
necessary equations for the dynamic design of steel columns and beam
columns.
(1) In the plane of bending of compression members which would
develop a plastic hinge at ultimate loading, the slenderness ratio *l/r
shall not exceed Cc defined by:
EQUATION:
Cc = (2[pi]2E/Fdy)1/2
(105)
where,
E = modulus of elasticity of steel, ksi
Fdy = cFy = dynamic yield stress
c = dynamic increase factor
The ultimate strength of an axially loaded compression member should be
taken as:
EQUATION:
Pu = l.7AFa
(106)
where,
A = gross area of member
[l - (K*l/r)2/2C2c]Fdy
Fa =
5/3 + 3(K*l/r)/8Cc - (K*l/r)3/8C3c
K*l/r = largest effective slenderness ratio.
(2) Members subject to combined axial load and biaxial bending
moment should be proportioned so as to satisfy the following set of
interaction formulas:
2.08-145
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