Problem 10.17

Here's a summary of the data:

L_e = 22 ft

column consists of:

W8 x 35... I_x = 127 in⁴, I_y = 42.6 in⁴, b_f = 8.02 in

2 plates of 9 in x 0.5 in

E = 29 x 10⁶ psi

F.S. = 2.3

There are two planes in which buckling is possible. Design has be done for the weaker plane; i.e., the plane for which the moment of inertia is the smaller.

For the plates:

The moment of inertia of the column is the sum of that for the W-shape and the plates. Clearly, the moment of inertia is smaller for the yz plane (subscript x): I = 60.75 + 127 = 187.75 in⁴.

The critical load is

The allowable load is this divided by the factor of safety, or 335 kips.