Column foundation for a frame house. Columnar foundations are used mainly in the construction of frame houses from different types of wood. The weight, and hence the pressure of such a structure on the soils, is much less than, for example, with brickwork of walls.
Therefore, the consumption of materials for the foundation is significantly reduced. Accordingly, it is really possible to save and keep within a lower price for formwork, support columns, etc.
You can easily make a columnar foundation with your own hands. The main element is the pillar, hence the name of the structure. It is usually made of stone, brick, rubble, wood, reinforced concrete mixtures. To create the shape, an asbestos pipe of the required diameter is used and filled with cement mortar. It is also permissible to have a square or even rectangular cross-section, which is simply laid out from blocks.
Or, formwork is used for molding.
There are several types of formwork. Disposable, removable, reusable, non-removable. When laying a columnar foundation, one of them is used.
Types of formwork:
Manufacturing plants began to produce cardboard disposable formwork. These are cylinders 3-22 mm thick, 110-1250 mm in diameter, up to 12 meters long. The paper is twisted in a spiral, which guarantees resistance to stress. In practice, the rigidity of such a product is small. And at a price the same as that of the AC pipe, it is not economically justified when building a one-story frame house.
Has a large volume. Delivery only by special transport.
Help! It is much easier to use ordinary roofing material, rolled up in two layers and placed in a well of the required size. Insulation will protect the pile from moisture and damage. The only negative is that it will not be possible to raise such a column above the ground to the required level.
Fixed formwork, similar in installation technology. It determines the shape of the future column, at the same time being a vessel for pouring the solution. Asbestos pipes can serve as such a container. They are placed in the wells and fixed with spacers. Or brickwork, hollow inside, like a well.
Most importantly, do not forget about the reinforcement cage before pouring the solution. Plastic pipes are also a good option for protecting the outer layer of the pile. This type of formwork allows the concrete to mature normally and gain the required strength.
Reusable demountable formwork is a set of elements fastened in different variations. Metal or plastic is used in professional construction for the construction of large facilities.
The blocks are universal, they set the section size of a different range. The height of a post of a given length. But for a frame house, even renting such a structure will be expensive.
The optimal and economically viable option is formwork made of boards or plywood.Shields of the right size are knocked down and stitched together for the time of concrete hardening.
For fastening, ordinary screws or nails are used, spacers are placed. Plywood panel formwork has several advantages. This is the absence of gaps and the speed of production.
After choosing the location of the future house, you need to clear the area and determine the quality of the soil. The pillars of the foundation are laid for the amount of soil freezing and the level of groundwater.
On sand, the depth of laying is not less than 0.5 m, on sandy loam, 0.7 m, on loam, it is equal to the calculated depth. It is most difficult to work with clayey soils. They have the ability to store water.
And when the soil freezes, increasing in volume, swells and presses on the foundation. The column can be overturned on its side or completely pushed out. Under such conditions, it is recommended to lay the greatest margin of safety, since it is impossible to calculate the behavior of the soil. The post is made monolithic reinforced with an extended lower part - "heel". Also, to strengthen the structure, a reinforced grillage is needed.
Help! When installing a reinforced grillage, the term of work increases by no less than a month.
To install pillars on normal soils, along the entire perimeter of the structure and under load-bearing walls, drill holes or dig holes- pits with a pitch of 120-250 cm. To the required depth with a small margin. And they fill in a layer of rubble plus a layer of sand.
Carefully install the pipe or lay a roll of roofing material with a metal mesh.
The reinforcement cage is lowered last. It is made from a rod 8-10mm in diameter. A medium-sized column takes 4 pieces. The length of the upper ends should be 30-70 cm above the edge of the column. This is needed for strapping.
The poured solution is compacted with a deep vibrator and the surface is leveled. The remaining space around the formwork is filled with sand and gravel mixture. After 10 days, after the concrete has set, the removable formwork can be removed. But the columns need to be given another month to mature.
On ready-made columns during the construction of a columnar foundation frame house we install the grillage.
It is a horizontally located element of a columnar foundation that serves as a base and distributes all the load evenly to the columns. It can be made of timber, reinforced concrete, steel. Concrete is poured in the form of a beam. This allows you to connect the pillars to each other over the entire area of the building.
In clayey soils, a monolithic tape grillage shows the most suitable characteristics.
However, the construction of such a structure has a high cost.
For one-two-story construction of a frame house, prefabricated tape-type grillages are used. The beam is laid on the head of the pile and joined. You can start building the house right away. Gas welded steel beams can also be used.
But the joints have medium strength and low stiffness, so they can simply break from the load. In this case, the seams are susceptible to corrosion. Therefore, wood and metal are not durable structures. The best option is a monolithic prefabricated grillage. When all the details on the piles are connected and monolithic.
Parameters of pillars and grillage are selected from the ratio of loads and bearing capacity of the base.
A columnar foundation with a recessed grillage needs protection against heaving of the soil. Therefore, the insulation of the blind area and the basement is carried out. Storm drainage is being arranged. A poorly insulated foundation gives the feeling of a cold floor.
In order to make the correct calculation of the structure of a columnar foundation, you need to understand that savings at one stage of construction may turn into a rise in cost at another stage.
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Posted By: Work Style |08, Nov 2020