Formulas: Tension Flange Yielding

Formula 1

(a) When $S_{x t} \geq S_{x c}$ , the limit state of tension flange yielding does not apply.

S_{x t} \geq S_{x c}

(b) When $S_{x t}<S_{x c}$

S_{x t}<S_{x c}

M_{n}=R_{p t} M_{y t}

where

$\begin{aligned} M_{y t} & =\text { yield moment in the tension flange, kip-in. (N-mm) } \\ & =F_{y} S_{x t}\end{aligned}$

$R_{p t}$ , the web plastification factor corresponding to the tension flange yielding limit state, is determined as follows:

(1) When $I_{y c} / I_{y}>0.23$

I_{y c} / I_{y}>0.23

R_{p t}=\frac{M_{p}}{M_{y t}}

(ii) When $\frac{h_{c}}{t_{w}}>\lambda_{p w}$

\frac{h_{c}}{t_{w}}>\lambda_{p w}

R_{p t}=\left|\frac{M_{p}}{M_{y t}}-\left(\frac{M_{p}}{M_{y t}}-1\right)\left(\frac{\lambda-\lambda_{p w}}{\lambda_{r w}-\lambda_{p w}}\right)\right| \leq \frac{M_{p}}{M_{y t}}

(2) When $I_{y c} / I_{y} \leq 0.23$

I_{y c} / I_{y} \leq 0.23

M_{p}=F_{y} Z_{x} \leq 1.6 F_{y} S_{x}

\lambda=\frac{h}{t_{w}}

$\lambda_{p w}=\lambda_{p}$ , the limiting width-to-thickness ratio for a compact web as defined in Table B4.1b

\lambda_{p w}=\lambda_{p}

$\lambda_{r w}=\lambda_{r}$ , the limiting width-to-thickness ratio for a noncompact web as defined in Table B4.1b

\lambda_{r w}=\lambda_{r}