Lateral Bracing Strength

It takes very little to brace a beam laterally. How little is little? I don't know. It would be a good topic for a research paper.

I use about 10% of the load on the beam. When applied to a tension member, 10% usually gives a fairly small brace.

Beef it up if it's for a crane beam or other dynamically loaded structure.

We've used 2% of the axial load in the compression chord or flange you are bracing.

Secondary bracing members used in towers and antenna supporting structures allows a resisting force between 1.5% tp 2.5% of the axial design compressive force in the supported member. This is given in Canadian Code S37-01.

Fs(tension/compression) = (0.015+0.008*(L/r-60)) * Cf

Cf = axail design compression of supported member

Hope this helps. Have a nice day!

Ayrom

for AISC, horizontal force
H=Af*fb*2%.
Af:area of compress flange, fb: compress stress

look at pg 16.1-21 in the "manual of steel construction LRFD 3rd edition" published by AISC