Propose the initial W sections and use A$992$ steel.

Assign descriptions to the beams, central column $($B axis$)$ and side columns $($A and C

axes$).$

Beams $AB$ and $BC$ have lateral bracing at their ends and at the center of the span.

Generate a second order analysis in LRFD as described in chapter C$,$ that is:

You will have to model the initial imperfections.

You will have to reduce the stiffness.

You will have to make sure that the effects are included and Run the design and

optimization routine. Repeat until no more sections have changed.

At the end of the design and optimization, it verifies the ratio between second$-$order

displacements and first$-$order displacements. Based on this quotient, make decisions

about your design.

With the resulting forces and moments, carry out the MANUAL verification of a beam

and the central column according to chapter $H.$ Compare the "stress ratio" obtained

with that produced by the program.