In the
larger engineering context, a foundation is the element of a structure that
connects it to the ground, and transfers the loads from the structure to the
ground, and depending on the design and structural needs could be constructed
deep or shallow. One such of the six different foundations is the foundation concrete.
These
foundations where structures will be constructed include the natural stone
foundation, rammed earth foundation, burnt brick, and concrete. The following
are some short details on each one, how they work and how are they compare with
one another.
Natural stone
Stone
foundations are made of the rubble (undressed stone) although similar
construction is possible with broken brick and concrete from demolished
buildings. The mortar’s quality is important in order to achieve strength.
A good
mix of materials usually include 4 parts cement, 1 part lime, 12 parts clean
sand and sufficient water to give a good mix.
Construction
should begin on firm, uniform strong subsoil. It cannot be on grass, black
fertile soil, filled up materials or mud. Under it should be a layer of lean
concrete, or tamped sand. In earthquake-prone areas, reinforcement of wire mesh
or steel rods is required.
Rammed earth
These
foundations are made of well-graded soil, preferably with a stabilizer for
water resistance and higher strength.
The
site should be well-drained and should be well-protected very well from ground
moisture, especially with a plastic foil or bitumen felt. Bitumen paint or a
facing of rubble stone or burnt bricks are alternatives.
If
suitability of the rammed earth foundation is in doubt, they should not be
used. Stabilized soil blocks can be used in place, but similar protective measures
are necessary. If possible, the earth foundation should be placed on a concrete
footing.
The
foundation is constructed in formwork in the same way as the walls. 10 cms. of
soil are tamped down to 6-7 cm before the next layer is filled up.
Burnt brick
Burn
brick foundations are principally the same as masonry walls constructions, but
begun under the ground, directly on a bed of tamped sand or lean concrete, or
on concrete footing.
The
base needs to be widened to distribute better the weight of the walls. Care
must also be taken to lay the bricks in perfectly level course and measures for
waterproofing are important.
Ideally,
a good mortar for masonry foundation is 4 parts cement, 1 part lime, 12 parts
clean sand and sufficient water to make a workable mix. In earthquake areas,
masonry should be reinforced with wire mesh or thin rods.
Concrete
Foundation concrete on hard uniform ground can be made without steel reinforcement, if away
from earthquake or hurricane prone area. All non-uniform and problem soils
would need reinforced concrete foundations, if the area is noted for high
rainfall and in hazard regions.
•
Concrete foundations on hard, uniform ground can be made without steel
reinforcement, if not in an earthquake or hurricane prone area.
• All
non-uniform and problem soils require reinforced concrete foundations,
especially in areas of medium to high rainfall and natural hazard regions.
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