Foundation is the basic structural part of a building which bears the whole load of all other elements. Therefore, the foundation should be strong, stable and durable, so as to ensure safety of the building thereupon throughout the entire service life.
To select the best fitting foundation option in each and every case, one should consider the whole variety of such structural elements.
Shallow foundations may be used in environments not susceptible to deep freeze and resulting deformation of soil. The foundation footing shall be 30-50 cm deep in the ground or above the freeze depth.
Deep foundations have their footing below the freeze depth.
Load-bearing foundations bear the whole load of the building thereupon.
Combined foundations provide seismic protection in addition to their load-bearing capacity.
Special foundations have properties required in extreme conditions, like earthquake-resistant rocking foundations or floating foundations.
Natural stone foundations: rubble, rubble concrete.
Manufactured stone foundations: brick, concrete block.
Reinforced concrete foundations.
Concrete foundations (including foamed concrete foundations).
Wooden foundations (rare option, more common are combinations with other materials).
Design, ground support methods
Post and pier foundations are used for small loads and solid beds. Posts and piers are allocated beneath the load-bearing elements of frame buildings or under the walls of compact low-rise edifices. These can be either classic or socket-type foundations.
Strip foundations are continuously cast to the shape of the load-bearing structure or piers.
Slab foundation is a continuous slab under the whole building or its part, used for heavy buildings on loose soils.
Pile foundation is a set of concreted piles immersed into the ground independently from each other. The foundation piles can be driven, confined concrete, bored, cast-in-situ, screwed, or other.
Continuous foundation is a rare kind of load-bearing structures, a monolithic bulk element, often round or square, used for large objects (bridges, aqueducts, hoppers, architectural and decorative structures).
According to the making technique, the foundation can be either cast-in-situ or prefabricated.
Foundation types according to physical properties and, respectively, application
Flexible/elastic foundations have bending strength, compressive strength and tensile strength. This is the commonest type of reinforced concrete foundations.
Rigid foundations (rubble, concrete, brick), unlike flexible ones, are resistant to compression only.