بخش 9.13.8.4.1

اگر M _a ≤ $\left ( \frac{2}{3} \right )$M _cr

$\Delta _{s}=\left ( \frac{M_{a}}{M_{cr}} \right )\Delta _{cr}$

اگر M _a > $\left ( \frac{2}{3} \right )$M _cr

$\Delta _{s}=\frac{2}{3}\Delta _{cr}+\left ( \frac{M_{a}-\left ( 2/3 \right )M_{cr}}{M_{n}-\left ( 2/3 \right )M_{cr}} \right )\left (\Delta _{n}-\frac{2}{3}\Delta _{cr} \right )$