Which foundation to choose for building a house depends on many factors: the depth of groundwater, the nature of the soil, the design of the house, the materials from which it is built, etc. One of the popular types of foundations is pile-gravel, which has a high bearing capacity.
Pile foundation: scope of application
The pile-foundation foundation is unpretentious to the type of soil. It can be used on unstable or mobile soils, on weak soils, low-strength or highly compressible, in places with a high level of groundwater. Often, the ground may become swollen due to deep freezing. In this case, this type of foundation will also be a way out. The system of piles buried in the ground 50 cm below the freezing level( usually from 1.5 m to 3 m in depth), redistributes the load from the building to the lower layers of the soil, more dense and durable.
Restrictions on the use of pile foundations are that there may be problems in horizontally movable soils( subsidence, swelling) due to low resistance to tipping.
Foundation foundation on piles
The main structural element of this type of foundation is piles - long pillars made of wood( oak, larch, pine, cedar), reinforced concrete or steel. One end of the pile is sharpened, on wooden stilts it is protected by a steel tip. The upper end has a steel ring, which protects against damage when driving into the ground with hammer blows.
Piles are connected between each other by a special design called grillage - an intermediate link between the underground and aboveground parts of the building, which gives rigidity to the whole foundation. It builds on the building under construction, and the load is distributed. The grillage can be low, high or intermediate.
Advantages and disadvantages of pile foundations
Like other load-bearing structures, the pile-and-foundation foundation has merits and demerits.
The main advantages of the pile foundation:
- has a high load-bearing capacity;
- is unpretentious to the types of soil;
- almost does not require the preparation of a construction site and the implementation of labor-intensive excavation( digging trenches, trenches) - just a few pits for piles.
Drawbacks of pile foundations:
- impossibility of installing a basement;
- complexity in the arrangement of the basement;
- need to erect a "vial" filling the space between the piles;
- need to use a specialized technique for piling.
Stages of the construction of the pile foundation
The process of building the pile-and-foundation foundation can be represented in several stages:
- Calculate the design of the bearing walls and prepare the foundation drawings, marking out the ground( read the markings here).
- The piles are hammered in places of marking with the help of a scraper hammer( or screwed piles are screwed into the ground) or with a gasoline drill bore holes for subsequent pouring of reinforced concrete piles.
- Prepare a wooden formwork for pouring grillage and overhanging pile tops above the soil level. If a recessed roof grill is made, trenches are prepared, in which a monolithic structure will be poured. In the wells, insert asbestos pipes or arrange a cover made of PVC film, roofing material, galvanized steel. Inside the formwork, the frame is reinforced from the reinforcement, while the reinforcement of the piles is connected to the grillage of the grillage.
- Pour concrete piles and grillage so that the reinforcement is immersed in concrete. Pouring is produced by layers, compacting concrete with a bayonet.
- Withstands a certain amount of time necessary for the hardening of concrete, and dismantling the formwork. Recommended height grillage - not less than 30 cm, width - about 40 cm( slightly wider than the thickness of the walls of the building).
The result is a solid and reliable foundation for a low-rise building.
As part of the mixture should not be broken brick, the remains of structures from gypsum, slag or ash. It is possible to fill only with clean river sand and gravel( 20-40 mm).
As you can see, the construction of the pile-foundation foundation is quite feasible even for non-specialists, the main thing is correct calculations, quality materials and observance of manufacturing technology.