A footing carrying a
single column is called a spread footing, its function is to "spread"
the column load laterally to the soil so that stress intensity is
reduced to a value that the soil can safely carry.
This is applicable in
any condition where the surface and near surface soils have a soil
bearing capacity that is adequate for the applied load. This may be
used on a single stratum; firm layer over soft layer or vice versa.
Spread footings are
often square in plan view and are of uniform reinforced concrete
thickness. Regardless of the allowable soil bearing pressure, they are
never less than 12 inches in width and their sides are of equal, or
nearly equal dimensions.
The depth of these
foundations may vary from project to project, and this is based on the
following:
- The Presence of a Basement
- Soil Conditions
- Climate
- Presence of Adjacent Structures
Dependent on soil
conditions, spread footings may bear on solid rock, native soils, or
controlled compacted fill. These recommendations are included in the
geotechnical investigation report.
Foundation Systems also
include:
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