When laying foundations for buildings on weak and moving soils, special elements are used - compound driven piles. Thanks to this, the structures acquire the necessary strength on unstable soils. Pile elements are made of wood, concrete, iron, but reinforced concrete are in the greatest demand.
Design Advantages
The advantages of pile products include the following indicators:
- Durability.
- High strength.
- No defects.
- Possibility to carry out ground work in the minimum volume during installation.
But most importantly, reinforced concrete structures are not afraid of aggressive chemicals and corrosion, which is very important when using products for installation on lands where groundwater rises close to the surface.
Scope of application
Consisting of two or more sections, reinforced concrete structures can have a maximum length of about 36 m.products have limited capabilities and cannot install them. The fact is that piles made of any materials must go deep into the ground until they rest against high-density soils. Otherwise, their use cannot provide the required stability, and then the building will sag during operation.
Note: unstable soils are peatlands and peaty soils, silty and clayey lands. It is impossible to build buildings on them without using pile products.
Composite piles are used not only for the construction of new buildings, but also for the reconstruction of those already in operation. To do this, at an object where there is limited space and it is impossible to use solid analogues, they reinforce the foundation of the building with additional supports. Typically, structures are used that consist of several parts, each of which has a minimum length.
Use reinforced concrete products from several sections and where it is impossible to deliver long structures due to inappropriate road or transport conditions. Use products of this type and construction companies that do not have pile drivers designed to drive structures, the length of which is from 12 m.
Design Features
According to GOST, composite piles are two joined elements - upper and lower. Products are produced in the following section:
- With a length of 14-24 m - 30 x 30 cm.
- With a length of 14-28 m - 40 x 40 and 30 x 30 cm.
The upper and lower parts of the products can have either the same or different lengths. For example, in products with a section of 0.3 x 0.3 m, the lower part can be from 7 to 12 m. The increment is 1 meter. Piles with a diameter of 0.4 x 0.4 and 0.3 x 0.3 m have a minimum length of the lower part of 8 m, and a maximum of 14. The length of the upper sections is from 5 to 12 and from 6 to 14 meters, respectively.
Important detail: there is a point on the lower section that sinks into the soil. It is necessary to improve the efficiency of the element sinking into the ground when driving or indenting.
Methods for connecting individual elements
Separate elements of composite piles are joined in one of the following ways:
- With the help of the welding connection of the embedded cup.
- Use a sheet steel pad that compresses the barrel, which is connected by a weld.
- Compressing parts are bolted together.
- Apply sealing tape, jig or rest on keyed protrusions.
- Use a flip lock.
- Pin connection.
- Using a high-strength construction adhesive, which fixes the reinforcement protruding in the mounting hole with the upper section.
The most reliable of these methods is the pin connection and the use of a welding mortgage cup - they are the most resistant to deformation.
Product marking
According to the technological requirements given in the document GOST No. 19804, the following types are producedcomposite piles series 1.011.1-10:
- Hollow round.
- Solid square designs.
- Sheath piles.
All types of structures are produced according to the standards specified in separate documents:
- Hollow products and pile-shells (the frame is made of non-tensioned reinforcement) are produced according to the requirements specified in GOST No. 19804.6-83.
- Pile-shells, the core for which is made of prestressed and non-prestressed reinforcement - GOST No. 19804.91. Products are allowed for installation in any construction industry. The exception is the hydraulic engineering sector.
- Products with a square section are produced with a frame made of non-tensioned and prestressed reinforcement according to the document GOST No. 19804-2012.
Each composite pile has a unified marking designation. Type of marking - Sp260.30. SV. The designation is deciphered as follows:
- SP - reinforced concrete hollow pile with a square section. If the designation C is present, this is a solid product, if CO is a shell pile, SC is a hollow structure of a circular cross section.
- 260 - an indicator of the total length of all parts of the product in dm.
- 30 - diameter of the trunk section in centimeters.
- Designation of connection type. SW - welded joint.
In addition to the above designations, there is also an abbreviation in the marking. She points to a part of the structure. For example: HC is the bottom part, BC is the top part, and A3 is its class.
Immersion Technology
Designs sink intosoil with a hydraulic or diesel hammer. It is strictly forbidden to use vibrators due to the fact that the welded joints of the frame can be deformed from the vibration effect. To facilitate the penetration of high density soil, it is recommended to use the leader drilling method. The application of this method will help reduce soil resistance. This is very important if you have to drive composite reinforced concrete piles to a depth of 20 meters or more. In order to rationally realize the immersion of structures, they additionally use excavator equipment with a crane boom. This will significantly speed up the installation, as the pile driver does not move the products on the construction site.
