Question

A rectangular footing $1m\times 2m$ is placed at a depth of 2 m in a saturated clay having an unconfined compressive strength of $100kN/m^2$. According to Skempton, the net ultimate bearing capacity is

• A. $420kN/m^2$
• B. $412.5kN/m^2$
• C. $385kN/m^2$
• D. $350kN/m^2$

Answer 1

The correct option is C $385kN/m^2$

(c)
$q_{net.ult}=c{N}_c$

$N_c=5(1+0.2\frac{B}{L})(1+0.2\frac{D_f}{B})$

$for\frac{D_f}{B}<2.5$

$=5\times (1+0.2\times \frac{1}{2})(1+0.2\times \frac{2}{1})=7.7$

$c=q_u/2=100/2$

$=50kN/m^2$

$\therefore q_{net.ult}=50\times 7.7=385kN/m^2$