Allowable compressive load on the saddle using Codeware

[Greenbee]

Fb = n*(As + 2*be*ts)*Sc

What is the As in the equation, how to calculate it for a saddle?

where Sc is allowable compressive stress psi; ts saddle web thickness; n number of saddle ribs;

be = di*ts / [di*ts + 2*tw*(b - 1))]
where di is maximum span of two ribs; b saddle width; tw rib thickness.


Thanks,