Formulas: Shear Strength of Webs

Formula 1

The provisions in Section G2.1(a) for rolled I-shaped members with $h / t_{w} \leq 2.24 \sqrt{E / F_{y}}$ are similar to the 1999 and earlier LRFD Specifications, with the exception that $\phi$ has been increased from 0.90 to 1.00 (with a corresponding decrease of the safety factor from 1.67 to 1.50), thus making these provisions consistent with the 1989 provisions for allowable stress design (AISC, 19

h / t_{w} \leq 2.24 \sqrt{E / F_{y}}

Formula 2

When $h / t_{\mathrm{w}}>1.10 \sqrt{k_{\mathrm{v}} E / F_{\mathrm{yw}}}$ , the web shear strength is based on the shear buckling and subsequent post-buckling strength of a web with nonrigid end posts.

h / t_{\mathrm{w}}>1.10 \sqrt{k_{\mathrm{v}} E / F_{\mathrm{yw}}}

Equation C-G2-1

The plate buckling coefficient, $k_{v}$ , for panels subjected to pure shear having simple supports on all four sides is given by the following (Ziemian, 2010):

k_{v}=\left\{\begin{array}{l} 4.00+\frac{5.34}{(a / h)^{2}} \text { for } a / h \leq 1 \\ 5.34+\frac{4.00}{(a / h)^{2}} \text { for } a / h>1 \end{array}\right\}

Equation C-G2-2

k_{v}=5+\frac{5}{(a / h)^{2}}

Formula 5

Furthermore, for $a / h>1.5$ , Equation F13-4 limits the maximum $h / t_{w}$ to 232 for $F_{y}=50 \mathrm{ksi}$ , and for $a / h \leq 1.5$ , Equation F13-3 limits the web slenderness to 289 for $F_{y}=50 \mathrm{ksi}$ .

a / h>1.5

Formula 6

a / h \leq 1.5

Found in

I-SHAPED MEMBERS AND CHANNELS