A highway overpass abutment weighing 2800 kN is proposed to be supported by a 4 m wide square footing sitting 0.5 m below grade on layered clay soil. The top layer of clay

extends from the ground surface to a depth of 1.5 m. Extensive soil sampling and

laboratory testing via unconfined compression tests indicate that the top clay layer has an

unconfined compressive strength of 240 kN/m2 and a unit weight of 16.8 kN/m3, and the

bottom layer has an unconfined compressive strength of 96 kN/m2 and a unit weight of

16.2 kN/m3

. Use the Army Corps of Engineers method (Also known as the adjusted bearing

capacity factors method, using the equations developed for clays using the provided chart

and table with a F. S =3) to determine whether or not this proposed footing design is

sufficient to support the design load. (Hint: the undrained shear strength is half of the

unconfined compressive strength,