Two L5 3 1/2 structural steel angles (see Appendix B for its cross-sectional properties) are used as a compression member that is 20 ft long. The angles are separated at intervals by spacer blocks...

Two L5

3

1/2 structural steel angles (see Appendix B for its cross-sectional properties) are used as a compression member that is 20 ft long. The angles are separated at intervals by spacer blocks and connected by bolts, as shown in Figure P16.8, a confi guration which ensures that the double-angle shape acts as a unified structural member. Assume that pinned connections are at each end of the column, and use E = 29,000 ksi for the steel. Determine the Euler buckling load for the double-angle column if the spacer block thickness is

(a) 0.25 in.

(b) 0.75 in.