We tell about the peculiarities of the screw piles presented on the market, as well as give advice on their proper installation.
The reinforced concrete screw was presented at the Mosbuild-2018 exhibition. Photo: V. Grigoriev
Types of screw piles
There are several varieties of screw piles that differ reliability and price.1. Products made of steel St3 thickness 3-5 mm Welded (marking SVS) with one-sided anti-corrosion coating
These are the cheapest piles (from 1200 rubles per pcs. At the diameter of the trunk of 108 mm, the blades - 250 mm and a length of 2 m). When installing them are required to concrete. Practice shows that steel protected by lead sulk or bitumen varnish corps in the clay water saturated soil at a speed of about 0.08 mm per year. Most likely, after 20-30 years, a critical weakening of the design will occur, which will manifest itself as a sharp increase in precipitation into the ground.
While the most common welded piles with bitumen anti-corrosion coating are most common. Photo: Dubldom.
2. Piles of carbon structural steel (ST20 et al.) Welded with double-sided polymer anti-corrosion coating
From 1600 rubles. per piece A modern polymer coating (for example, based on epoxy resin) protects the metal from corrosion for 10-15 years - at this time there should be a pile service life. But only if the manufacturer followed the technology of application of the composition (this may confirm the examination) and if the coating was not damaged during the passage of the pile through the layers of coarse sand and gravel (which is practically impossible).3. Galvanized steel piles with cast tip
strong>(SVL)From 2800 per pc. The carrying ability of pile is not provided with a trunk, but a tip (blade), based on the dense layers of the soil and below the depth of freezing. The weak place of welded pile - the fastening of the blade to the trunk. Piles with cast tip do not have welded seams and therefore serve at least one and a half times longer.
Alloy tips are much prolonging the service life of the foundation. Photo: OZMK
4. Stainless steel piles with cast tip
From 12 thousand rubles. per piece Such products have a service life of more than 60 years, but by virtue of a very high price, their use justifies itself only in exceptional cases (for example, when installing on the water - if you can not use a pile technique).
The headings for fastening the wooden strapping are sold separately. Photo: Kuznetsky Alliance
5. Reinforced concrete screw piles
This is the recently patented development of Russian specialists. Such a pile, screwed by a special "key" from the steel pipe of the square section, theoretically must have a very long service life. Alas, the mass release of such products has not yet begun.
Strengthening design is performed from metal. Photo: Piles 47
How to mount piles
one. When installing, it is necessary to monitor that the tip relies on the dense layers of the soil. That is, for example, if at the design depth of the attachment of an enlistence sharply decreased (presumably, the tip hit the weak-to-carry water saturated sand), it is necessary to continue the process until an effort will increase, even if it is necessary to put the pile trunk, welding pipe sections.
In the presence of a metal frame, the strapping bar can be a cross section of 50 × 100 or 50 × 150. Photo: Piles 47
2. In no case cannot be combined with screw piles with reinforced concrete woodwork on the ground: frosty powder forces are raised by Rural, and piles or their blades, firmly sitting in the ground, will tear off. Concrete woodwork necessarily post, for example, with the help of a removed sandy submet. But rational use metal randbalki.
The lumen under the house built on the piles, is usually closed with a panel or rack. Photo: Dubldom.
3. With the height of the Editions of the piles, more than 50 cm, the pile-screw foundation is required to strengthen the disclosures, otherwise the vibration will be felt in the country house when walking.
Pile blades must be in a layer of dense soil
Piles are mounted in a matter of minutes using a mobile installation with an electric drive. Photo: AMC Group