Chapter 7, Problem 7.5QPP

A column carrying a vertical downward ultimate factored load of 1 ,500 kN is to be supported on a 1 m deep square spread footing. The soil beneath this footing is an undrained clay with $s_u=150\text{kPa}$ and $\gamma =18.1{\text{kN/m}}^{\text{3}}.$ The groundwater table is below the bottom of the footing. using the LRFD method, compute the required width B. Assume the geotechnical resistance factor is 0.5.