Factored shear resistance, V_r , developed by the web of flexural member is calculated as:

where

Aw

=

shear area

F_s is evaluated as:

1. For unstiffened webs (Cl. 13.4.1.1.(a) ):

   1. when $\frac{h}{w}\le \frac{1,014}{\sqrt{F_y}}$, F_s = 0.66F_y

   2. when $\frac{1,014}{\sqrt{F_y}}<\frac{h}{w}\le \frac{1,435}{\sqrt{F_y}}$, $F_s=\frac{670\sqrt{F_y}}{(h/w)}$

   3. when $\frac{h}{w}>\frac{1,436}{\sqrt{F_y}}$, $F_s=\frac{961,200}{{(h/w)}^2}$

2. For stiffened webs (i.e., when the STIFF parameter is specified) (Cl. 13.4.1.1(b) ):

   1. when $\frac{h}{w}\le 439\sqrt{\frac{k_v}{F_y}}$, F_s = 0.66F_y

   2. when $439\sqrt{\frac{k_v}{F_y}}<\frac{h}{w}\le 502\sqrt{\frac{k_v}{F_y}}$, F_s = F_cri

   3. when $502\sqrt{\frac{k_v}{F_y}}<\frac{h}{w}\le 621\sqrt{\frac{k_v}{F_y}}$, F_s = F_cri + k_a(0.50F_y - 0.866F_cri)

   4. when $621\sqrt{\frac{k_v}{F_y}}<\frac{h}{w}$, F_s = F_cre + k_a(0.50F_y - 0.866F_cre)

   where

   Ae	=	shear buckling coefficient: when a/h < 1, $k_v=4+\frac{5.34}{{(a/h)}^2}$ when a/h ≥ 1, $k_v=5.34+\frac{4}{{(a/h)}^2}$
   a/h	=	stiffener aspect ration (i.e., ratio of the distance between stiffeners to web depth)
   Fcri	=	$290\frac{\sqrt{F_y{k}_v}}{(h/w)}$
   ka	=	aspect coefficient = $\frac{1}{\sqrt{1+{(a/h)}^2}}$
   Fcre	=	$\frac{180,000k_v}{{(h/w)}^2}$

For tubular members, the shear resistance, V_r , is calculated as:

where

Ae

=

the cross-sectional area of the tubular member