Looking at AISC 360-10, Appendix 6, 6.3 Beam Bracing (Relative Bracing).
We have equations A-6-5: Prb = 0.008*Mr*Cd/h0
And equation A-6-6: βbr = (1/Φ)*(4*Mr*Cd/Lb*h0).
h0 is defined as the distance between the flange centroids. But what if the beam you are bracing is not a W, S, or HP...
On ACI 318-11, chapter 22, section 22.5.4 we have the equation for beam-action shear as: Vn = (4/3)*λ*(sqrt(f'c))*b*h.
Chapter 22 has no references at all, but the commentary indicated the expression is derived from v=VQ/Ib (Mech of Materials equation for shear stress). I suspect the 4/3 part...
