Question $4(40$ Marks$)$

Design bored piled foundation for a bridge pier subjected to a vertical characteristic

permanent load of $13260kN$ and a vertical characteristic transient load of $5350kN$ in a

two layer of deep deposit of sandy soil with the water table at $5m$ depth. The upper layer

of sandy soil has a unit weight of $=16k\frac{N}{m^3},c^{\text{'}}=0$kPa and ${}^{\text{'}}=26.$ Below this lies a

dense sandy soil at a depth of $10m$ of unit weight of $=18k\frac{N}{m^3},c^{\text{'}}=0$kPa and ${}^{\text{'}}=$

${33}^0.$ Take the weight density of concrete of $24k\frac{N}{m^3}.$

i$.$ Select the pile diameter and pile depth. Determine resistance of the single pile

according to Eurocode $7$ GEO ultimate limit state $($Design approach $1-$

combination $1).(20$ marks$)$

ii$.$ Design pile group and confirm that pile group resistance is greater than the design

load using Seiler$-$Keeney formula. $(20$ marks$)$