Seismosoft | Earthquake Engineering Solutions

Hi
I have modeled a steel moment frame with Inelastic plastic hinge frame element - infrmFBPH and bilinear steel model.
Unfortunately i cant Compute the plastic hinge length [V][V]
can you help me to compute plastic hinge length for W18x50 section with fy=50ksi and L=25ft??[?]

and is this the plastic hinge length (Lp/L)for one side of Member or sum(total) of two side of my member???

thanks for the answer