Shallow foundation: reinforced shallow foundation ( strip foundation) & direct shallow foundation
Foundation on steel is also known as " floating slab or direct foundation".
What do you see in the following image?
> Soil testing or soil probing is required.
> Design of shallow foundation with proper size, shape and depth of foundation.
> Ground preparation consists of leveling and compacting the soil.
> Soil testing in photo below.
* This type of foundation is a construction of concrete strips.
* They are laid where the walls are to be.
* The width of the strips should be proportional to the load the walls will bear.
* Exterior walls, i.e. cavaty walls, should be able to rest on wider strips than interior walls.
> Construction of a strip foundation:
* The height and width of the strips or trenches are determined by probing and the type of building.
* A good estimate for the width of the trenches is 2.5 to 3 times the width of the wall coming up.
* That means +/- 70 to 90 cm width for cavity walls.
* So for a cavaty wall this means: façade = 10 cm , insulation = 12 cm & inner cavity wall = 36cm x 2.5 = 90 cm.
* For interior walls it is easier, you take the width of the wall ( 14 or 19 cm) and multiply it by 2.5 or 3 depending on the size of the building.
* The trenches should be excavated sufficiently deep to the frost-free depth. Usually this depth is between 80 and 120 cm underground.
* Reinforcement is placed in the trenches and on top of the trenches one places a lightly reinforced floor slab, usually 12 cm thick.
* One can also use vaulting.
* If one uses vaults, one often puts a layer of concrete blocks between the foundation and the vault.
* Before placing reinforcement in both foundation and floor slab, lay a plactic sheet, both in the trenches and where the floor slab will be placed. Don't forget the grounding loop as well.
* When concreting the foundation and floor slab together, take into acoount the placement of all drains and utilities.
* Concrete is poured using a concrete mixer possibly with a concrete pump if necessary.
Actually this type of foundatiion is the same as the strip foundation, except that no reinforcement is applied here.
For concreting, in- situ concrete is used here.
What is in-situ concrete?
Concrete created at the plant and brought to the site by concrete mixer.
Resource information