$13$:$58$

$*$I LTE

AFE$4801$ Major Test $32024($upload$)$

Question $2$

A square footing is founded at a depth of $1\mathrm{.}5$ m in a sand with the water table also at $1\mathrm{.}5$ m $.$ A load of $150$ kN acts at an inclination of $10$ to the vertical, halfway between the centre of the footing and one of the corners. The following soil properties are given: $c^{\text{'}}=0$kPa,$c_u=80$kPa,${}^{\text{'}}=35{}_{\text{b}\text{u}\text{l}\text{k}}=17k\frac{N}{m^3}$ and ${}_{\text{s}\text{a}\text{t}}=20k\frac{N}{m^3}$

$2\mathrm{.}1$ Formulate $q_f$ in terms of FoS.

$(5)$

$2\mathrm{.}2$ Formulate $q_f$ using the formula: $q_f=C^{\text{'}}{N}_c{S}_c+(yd{N}_q{S}_q)i_q+(0\mathrm{.}5B^{\text{'}}{N}_{}{S}_{})i_{}$

$2\mathrm{.}3$ Calculate the width of the foundation for drained conditions if the factor of safety of $3$ is required for the design.

Hint: For this question, you should use the $i_q$ and $i_y$ as multipliers on the bearing capacity equation $($the formulas are on the formula sheet provided during discussion sessions$).$

$[25$ marks$]$

Question $3$

A square Reinforce Concrete pile with a width of $350$ mm is driven through seabed for a jetty structure to carry a maximum compressive load of $500$ kN and a net uplift load of $300$ kN $.$ The soil below seabed consists of a $10$ m thick layer of saturated medium dense sand overlying dense sand and gravel. The average corrected Standard Penetration Test blows in the top $10$ m sand are $12$ and on bottom sand gravel layer is $40.$ No erosion is expected. The minimum safety factor should be $2\mathrm{.}5$ on the uplift load and $4$ on the compressive load. Consider the sketch below.

$3\mathrm{.}1$ Determine the required penetration depth.

$(9)$

$3\mathrm{.}2$ Perform the necessary checks for compression loads.

$(8)$