Shallow foundation

Among a raft foundation is understood in building a form of creation, in which the structural loads are routed directly below the building into the ground.

In the shallow foundation must be taken to ensure that they (at least 80 cm in Germany ) integrates at least below the frost line in the ground. This prevents that elevations and reductions, and thus cracks arise in the freezing of the soil.

Different types of shallow foundations

Examples of shallow foundations are footings, strip footings and raft foundations as they are used in many buildings.

Difference shallow foundations / deep foundations in construction practice

Basically, should be investigated for economic reasons, first, whether the simpler form of shallow foundation can be selected.

A deep foundation is generally selected only when the load-bearing soil layers pending only at greater depths.

The load capacity of shallow foundations can be controlled by the foundation sizes and the embedment. They must be chosen so that both the stability is guaranteed, as well as the deformations are compatible.

For sustainable soil layers at depths easily accessible also a floor replacement more economical than a deep foundation can be.

Between shallow and deep foundation, there are also intermediate solutions such as Piers or fountain -ups. Here the non-bearing soil is previously undeveloped or selectively installed excavated and replaced with plain concrete.

If it is necessary shoring for this well shaft rings are often used (well founded ). You will be excavated from the inside, thereby simultaneously lowered down to sustainable soil layers. You will then be filled with plain concrete.

The best-known example of an unsuccessful shallow foundation is the Leaning Tower of Pisa.