Calculation of screw piles for the foundation. How to make the correct calculation of the load?

It has long been no secret that the correctness of the choice of the basis for the house and the quality of construction determine the service life and the convenience of living in it. Calculation of screw piles for the foundation is still necessary at the stage of project development, since without this information it is not possible to prepare estimates, purchase tools and materials.

Design Features

Metal screw piles for foundation due to its universality deserve wide application among developers.

What are the features of the piles?

• Design. This is a welded pipe with a sharp end, on which the blades are screwed in the form of a screw - a fixing element that does not allow the pile to move from its seat while expanding the soil, keeping the entire structure stably.
• Installation. Installation is carried out with a clear control of the verticality of the pipe, it is made by mechanical or manual method. The main requirement is that drilling takes place before a stable layer of soil. Screwing piles is made regardless of the season and precipitation.

Indicators influencing the calculation

Calculation of screw piles for the foundation will require determining the total load on the base of the house, which consists of:

1. The mass of construction, installed on the foundation. When designing a house, the mass is a calculated index, it is determined by the materials embedded in the construction.
2. An additional load, including snow, furniture, equipment and people. Information for calculation of loads on the foundation must be taken from the approved normative documents SNIP No. 2.01.07-85. The payload in the form of people and furniture is assumed at an average of 150 kg per m ² .
3. Density of the soil. To determine the need for engineering and geodetic research, since without these works the facility will not pass state expertise. The calculation is carried out according to SNIP No. 2.02.03-85.
   For private construction of houses up to 3 floors, you can do research on your own.

After calculating the nominal loads, it is necessary to take into account the safety factor equal to 1.2.

Types of piles

Calculate the foundation of the screw piles for the house is impossible without a preliminary choice of their kind. Each size is calculated for a certain type of erected object.

The choice of length depends on:

• Horizontality of the construction site: if there are significant differences in height, it is possible to choose piles of different lengths.
• Nature of the soil. A reliable installation involves screwing up to a stable soil and below the freezing level of the soil by 25 ÷ 40 cm. At the same time, the pile part must go to the ground no higher than 1500 mm.

The length is standardized:

• Short: 1,65 ÷ 2,5 m.
• Long: up to 11.5 m (step 500 mm).

Calculation of the number of screw piles for the foundation: stages

It will take:

• Plan the site on a scale on which you want to apply the planned base with the center lines.
• Snap to the lines of communication: a sewer pipe from the plumbing rooms and from the kitchen, with the drawing of diameters.
• Results of engineering-geological research.

Location:

• Single - point supports for light structures or country houses.
• The tape is a consistent arrangement with a certain pitch.
• Bush - for heavy houses with a lot of partitions and for every support in the frame construction.

Calculation of screw piles for the foundation is carried out taking into account the design features:

• The distance between the support points must be at least 2500 mm.
• The pile should be installed in places of peak loads that are centered at the intersection of perpendicular lines, namely:

1. In the corners of the building.
2. At the joints of load-bearing walls and partitions.
3. Intermediate supports should be installed evenly, including on the diagonals of the main building cells.
4. The size of the piles and blades is determined depending on the type of load and the characteristics of the soil.

Influence of soil on calculation

Whatever the piles are screwed for the foundation, the calculation of the load is impossible without determining the bearing capacity of the soil. So, not always the soil has the necessary composition, allowing you to withstand the construction without sagging.

Important! The selected pile should not exceed the value of the soil load withstand.

To determine the bearing capacity of soils , the soil composition is first determined, and then compared with the characteristics given in the table.

In order to calculate the screw piles for the foundation, you need to determine the type of soil:

• Sand of coarse fraction: 2.5 ÷ 5 mm one grain of sand, up to 2 mm - medium. Does not change its size.
• Sandy loam is obtained by mixing sandy with an insignificant percentage (10%) of clay rock.
• If the clay content is up to 30%, a loam is obtained. When wet, the mixture does not spread, but can be rolled into a ball, but when pressed, cracks appear.
• If a lump of moist soil does not crack at pressure and is crushed plastic, the clay composition is above 30%.

Note! The greater the clay content, the higher the swelling of the soil.

• Peat - a soft and airy composition does not imply carrying loads.

The proximity of groundwater and the degree of moisture resistance is determined by drilling the well at the depth of the pile lowering. If there is water in the standing pit, then there is a moisture saturated ground with a close location of the aquifer.

Piles screw for foundation: customer reviews

Reviews about the piles depend on where the buyer purchased the products, as many complain about the inappropriate manufacture, including poor anti-corrosion treatment. The owners of houses on complex water-saturated grounds praise the construction in most cases, since the pile for such a site is the cheapest and most reliable kind of basement. Also do not forget about the speed and high quality of installation of such buildings in any weather, this is the plus noted by many developers.

Total

Use a pile as a foundation for construction or not - depends largely on the terrain and installation conditions. Knowledge of calculation rules and data sources is desirable even in cases when the calculation is carried out by a construction company.