Piles are intended for the manufacture of foundations of structures and buildings in order to transfer the load to the soil, as well as to increase its bearing capacity. The foundation is characterized by durability, ease of arrangement and low cost. The types of piles depend on the material used, manufacturing technology, form and method of immersion.
The difference in assortment lies in the materials used and immersion technologies. In this case, the installation of piles depends on the properties of the material and design features. The following types of materials differ:
- reinforced concrete or concrete piles;
- wooden;
- metal.
Classification is also made according to the methods of immersion in the soil, directly related to mechanical properties and design features.
Piles: types of diving
Piles of any material are divided into hanging and racks. The former are used for soft soils of great depth. They transfer the load not only to the lower end, but also to the friction between the ground and the side surface. The racks are supported by the lower end on a dense base, which perceives the entire load.
Pile designs are interconnected with the method of immersion and are of the following types.
- Hammered - using hammer blows, using vibrators or indentation devices. The method is used if there are no other structures nearby that can precipitate from ground shocks.
- Hollow pile piles. They are immersed in the ground by vibration to remove the soil from the inside and replace it with concrete.
- Drilling - wells are drilled and filled with a mixture of concrete with reinforcement or a reinforced concrete element.
- Stuffed - a well is made by compressing the soil and poured with concrete mixture.
- Screw - screwed into the ground.
Wood piles
The wooden foundation is used for light houses, in which the weight per 1 m 2 of the area is lower than the norm. It is being erected for buildings with the same service life. Usually these are temporary and farm buildings, small shops, car washes, cafes. For such structures, expensive approvals for capital structures are not required.
Types of wood piles are classified by the type of lumber used for their manufacture. They are made of pine, spruce, cedar, larch, oak, etc. The logs are taken straight and cleared of bark. Piles are made with a length of 4.5 to 16 m and a diameter of 20 cm. If the penetration is significant, wooden piles are built up to a maximum of 4 elements. From the bottom, the end is ground to a cone, the length of which is 1.5-2 trunk diameters. With too dense soil or with hard inclusions, a metal shoe is put on from below. The upper end face is protected with a metal ring (yoke) to protect against deformation when driven.
Before immersion, the piles are impregnated with compounds from decay: special coatings, firing. Then they are additionally covered with creosote oil or osmolka and wrapped with antiseptic bandages.
Wells 1.5 times larger in diameter are usually drilled under the pillars of the foundation. From below, stones or concrete mix are used for support. After installation, the poles are buried and rammed tightly. With proper processing, wooden piles last up to 20 years.
Reinforced concrete piles
Piles can be delivered to the construction site ready, in the form of beams, or poured into the formwork mounted in the drilled well.
The types of construction of piles can be round or polygonal, with pointed lower ends. The length reaches 16 m, the size in the cross section is from 20 to 40 cm.
The most common products are square sections, as less time-consuming and more technological in manufacturing.
Pile foundation, types of piles
The foundation is created from a group of piles connected from above by beams or slabs (grillages). A single pile can withstand significantly less load compared to the weight of an overhead structure. Therefore, the supports form in groups.
1. Monolithic piles
Before driving a pile into the ground, first a hole is drilled in it at a depth of 1.5 m, into which a column is inserted. Then a crane with a hammer or a ram is brought in and driven into the required depth. The free space of the calibrating hole is filled with concrete.
Reinforced concrete hollow piles consist of links connected by welding or bolts. In their lower part, the soil remains, and concrete mortar is poured into the upper part to ensure connection with the foundation.
2. Bored piles
The types of piles for the foundation also include structures made directly at the construction site.
Bored support is made as follows.
- A well is drilled into the soil to the depth of the pile. To do this, the soil is drilled or punched. In the first method, soil walls can be reinforced with casing or clay. When the bottom mark is reached, the space under the base is expanded with a special device mounted on the drill rod.
- A pipe made of roofing material and a formwork of four reinforcing rods with horizontal dressings are inserted inside the well.
- The inner space is filled with concrete mortar with a vibrator seal.
Metal piles
As piles, a rolling profile is used: an I-beam, channel or pipe. Sometimes they are pre-trained. For this, 2 channels are welded together, thus obtaining a square pipe.
Piles can also be of open section. They are made by welding corners, rails, I-beams.
Metal is used in cases where it is impossible to install reinforced concrete piles. It is easier to build up as it goes deeper into the ground.
Metal profiles have high strength, which simplifies their driving into the ground. For a small cross section, solid inclusions or destroyed rocky soils are not terrible.
Piles are driven into the ground with a hammer or press. With a depth of up to 5 m, the use of a manual hammer is sufficient.
Special types of piles among metal products are screw. Providing high strength, they are more economical and more technological than reinforced concrete foundations. Piles are hollow pipes with outer blades. They are screwed into the ground, like screws, preserving its structure and additionally compacting. In this case, rotation in the opposite direction is not allowed so as not to degrade the characteristics of the base.
Benefits of Screw Piles
Screw piles have the following advantages:
- lack of earthwork;
- the possibility of house building on difficult terrain and soft soil;
- ease of attachment to finished architecturally formed areas;
- high bearing capacity;
- lack of shrinkage;
- the ability to install near communications and at any time of the year;
- durability.
The screw pile foundation is used on soft ground, where there is high humidity, freezing and fluidity. It will not be possible to build a basement with it, but this drawback is characteristic of all types of pile foundations.
When choosing screw piles, you should pay attention to the following factors.
- The basis is a new steel pipe with sandblasting and a reliable anti-corrosion coating. The wall thickness should be at least 4 mm, and the blades should be more than 5 mm.
- The pipe outside should be smooth, without protruding welds, and the blade should be of the correct shape.
- High demands are made on the quality of welding, otherwise the joints will not withstand when screwed into the ground.
The following types of screw piles are available:
- cast, with high strength connection of the blade with the pipe;
- welded - with welding of the blades on the pile body;
- combined, assembled in two parts - blades with a cone.
Screw piles are not mounted in rocky and rocky soil, although there is special equipment for such an installation.
Installation of screw piles
- The appropriate standard size of piles is selected based on the calculation and analysis of the soil.
- Marking is made, and the pile is installed in the required place.
- Screwing is carried out using special equipment, but sometimes it can be done manually using levers. At the same time, 2-3 people perform work. Depth should not be less than 1.5 m.
- The pile field is trimmed at one level.
- Concrete may be poured inside the pipes.
- Goggles are welded on top of the piles, and then they are strapped with a channel or logs. Welds are lubricated with mastic against corrosion.
Conclusion
Technologies for the use of piles in construction make it possible to solve the complex tasks of erecting buildings and structures in simple and affordable ways. The diverse types of piles, unlike other foundations, allow you to develop underground spaces in any soil and in built-up areas.