Several cone penetration tests have been conducted at a site underlain by a young, normally

consolidated silica sand deposit. Based on these tests, an engineer has developed the following

design soil profile:

This soil has an average unit weight of 18.1 kN/m3 above the groundwater table and 20.8 kN/m3 below. The groundwater table is at a depth of 3.1 m. An office building with a parking structure

is to be built at this site with ASD column loads of 400 to 1,500 kN and service loads of 380

to 1,100 kN. Square footings are to be used at a depth of 1 m. Using these data, create design

charts for both serviceability and ultimate limit states using ASD with a factor of safety of 2.5

and a design life of 50 years.

Hint: In a homogeneous soil, the critical shear surface for a bearing capacity failure extends

to a depth of approximately B below the bottom of the footing. See Chapter 4 for a correlation

between qc

in this zone and f′.