Problem $3\mathrm{.}2$

$($a$)$ You are designing a continuous strip footing to support the walls of a tilt$-$up structure. The wall loads will be $25$

kip$/$ ft along the length of each wall. The footing will be founded at $3$ ft depth below ground surface on a medium

dense sand with $c^{\text{'}}=0,{}^{\text{'}}=33,$ and $=124l\frac{b}{f}{t}^3.$ The groundwater is at a depth of $4$ ft below ground

surface. Using a factor of safety of $2\mathrm{.}75$ for bearing capacity, compute the minimum required footing width.

$($b$)$ Repeat part $($a$)$ with everything remaining the same except the water table is now at a depth well below the bottom of

the footing.

$($c$)$ Repeat part $($a$)$ again with everything remaining the same except the water table is now at a depth essentially at the

ground surface.

Use Terzaghi's original bearing capacity factors.

Answers: Part $(a)B=4\mathrm{.}25ft$

Part $(b)$ use ${}^{\text{'}}=$ and recalculate $B$

Part $(c)$ use ${}^{\text{'}}={}_b=-{}_w$ and recalculate $B$