The foundation is the basis of any capital structure, the strength and integrity of the structure erected on it depends on the quality of its construction. In cases where the natural properties of the soil do not allow the use of an ordinary type of support, pile construction is used. Before starting any construction, it is important to know how to build a pile foundation with your own hands. Step-by-step instructions, videos and a general description of the process will help you with this.
The main purpose and types of pile foundation
Pile foundation is used in the construction of industrial and residential buildings, it can be used in the construction of multi-storey buildings, even on weak soils. This foundation can significantly reduce the process of the device basement or completely eliminate these construction work from the cost estimate. The main reasons for the construction of the pile foundation are as follows:
- weak top soil layer. Such soils may contain humus, peat admixture, sand, clay. The presence of a large amount of water in the soil makes it float. Such natural conditions create the need to transfer the load of the structure to more dense and deep soils;
- increased soil density. Using a pile foundation, you can reduce the amount of ground work. It will also reduce the cost of preparation: digging the pit, hiring trucks, removing excavated soil, filling, buying concrete and more.
The pile foundation has several varieties: pile-grillage, pile-screw, pile-tape. The advantages and disadvantages of each type have, consider them in more detail.
The use of pile-grillage bases has both positive and negative sides. The advantages of such a foundation:
- allows you to build on almost any kind of soil;
- increased resistance;
- increased bearing capacity (allows to hold roofs and walls with a rather large specific weight);
- profitability (no need to use ready-made solution, you can make it yourself);
- the solidity of the base allows the precipitation of the whole structure in case of shrinkage of the soil;
- does not require special preparation of the construction site (cost reduction by reducing labor-intensive work);
- ensuring natural ventilation of the whole lower plane of the structure (moisture decreases, condensate is eliminated);
- safety (reduced risk of flooding in the event of flooding);
- speed of construction;
- high construction speed.
Important! The construction of the foundation on piles requires accuracy in the calculations and compliance with construction technology. When overloading tonnage pylons there is a big risk of building destruction in the future.
Disadvantages of pile-grillage foundation:
- the impossibility of erecting a pile-grillage foundation on stony soils;
- the complexity of the installation of the base when the horizontal displacement of the soil;
- a rather high price of the pile-grillage foundation, which is much higher than the cost of other options;
- the impossibility of building a basement or basement premises (this type of foundation is used exclusively for lightweight and medium-weight structures);
- accuracy of calculations (errors in the calculation will lead to deformation of the supports and the formation of cracks in the house). It is not cheap to order the calculation of the pile-grillage foundation from specialists. Consequently, the total price of work will increase significantly.
This technology is known since the last century, so its pros and cons have long been studied. Benefits:
- low price of the pile and screw base which is many times cheaper than monolithic or tiled;
- high erection speed (there is no need to level the ground or dig trenches);
- minimal disturbance of the soil structure;
- lack of vibration (the ability to build buildings near the monuments of architecture, monuments, ancient trees);
- recommended for installation on marshy ground, the banks of reservoirs (an ideal choice for the construction of the pier);
- complete independence from weather conditions;
- repeated use of the structure;
- installation work is carried out at minimum cost (physical, technical).
Disadvantages of pile and screw foundation:
- the supports are highly susceptible to corrosion (iron alloys are used for manufacturing);
- structural fragility;
- the impossibility of using the space under the house (it is strictly forbidden to build a basement or basement).
A fairly common type of foundation, which also has its own specific features. Advantages of the pile foundation:
- can be erected on sites with difficult land relief;
- profitability (the minimum number of involved equipment and human resources in the construction of structures);
- ability to withstand weak shocks and ground movements;
- piles can be made independently using only the available material;
- speed of erection.
How much is the foundation for a standing house: calculation, cost and order of work. Types and types of foundations. How to fill the foundation for the house with their own hands, photos and video of the process.
Disadvantages of pile foundation:
- the need for detailed geodetic measurements;
- individual calculation of the length, thickness and depth of each pile;
- the inability to create a basement;
- mandatory work on the insulation of the underground;
- used exclusively for the construction of low buildings (maximum three floors).
Currently, the cost of any construction work has increased significantly. Therefore, many owners solve the problem of building a foundation with their own forces and all sorts of improvised means. Consider in detail the main points of the construction of three types of pile foundation.
This kind of the base has a characteristic design of the concrete basis. It fixes a beam, which is poured out of concrete and reinforced with reinforced elements. This is a unified system consisting of supports (piles) and grillage.
The support function is performed by round or rectangular pillars. The pillars are immersed at a specially calculated depth. It is on them that the entire weight component of the building is held. Rostverk is a monolith that unites all installed piles.
Pile foundation foundation can be built independently, because there is no need to remove the soil. In order to drive the supports into the ground, special pressing devices are used. After the final installation of the piles, they are cut at the same level. Then, a common connection is carried out with a grillage, which ensures a uniform load on each individual support.
A photo of the pile-grillage foundation will show it much better than any detailed description. Often, the foundation supports are metal hollow pipes from the inside. This makes them easier compared to other types of piles. They are easier to score at a considerable depth. To increase stability, concrete is poured in.
Important! The rostverk in this case serves as a reliable and rigid basis for the next stage of construction – masonry.
Rostverk can be done in two ways:
- Assemble from reinforced concrete elements.
- Pour the monolithic tape.
For the construction of the foundation with your own hands it is better to choose the second method – a monolithic grillage. This will greatly facilitate the task of pouring concrete. The installation of heavy concrete blocks will require additional labor and technology. The sequence of actions is as follows:
- consider a small space between the ground and the lower boundary of the grillage. This will help keep the entire structure from expanding;
- mark the future location of the piles;
- drill holes and install piles;
- formwork should be laid on top;
- inside the formwork assemble reinforcement cage. It is necessary that it be completely immersed in the concrete solution. For this, small bars should be placed under the lowest bars;
- protruding from the support of the rods need to be connected with a roaster of the reinforcement cage. This will provide the foundation with greater reliability and durability;
- after that the grillage can be poured with concrete. Concreting is done in layers to avoid the appearance of air pockets.
To choose the right kind of foundation, you need to start from the approximate weight of the future house. The pile-grillage foundation has rather high load restrictions, therefore it is suitable as a base for aerated concrete buildings, panel board and frame houses. It is not recommended to use this type of foundation for high-rise buildings due to the low resistance to overturning loads that occur on mobile soils. The best option is the use of pile-rostrum foundation for aerated concrete.
Helpful advice! The width of the grillage should be slightly larger than the width of the walls of the future structure. This will add sustainability to the building.
The total number of piles and their pitch is calculated for the construction of a one-story building with a size of 7×7 m.
Approximate weight of consumables (roof, timber, cladding, etc.) is 25,000 kg.
Payload: 7x7x150 (accepted value for residential premises) = 7350 kg.
Snow load: 7x7x180 (constant) = 8820 kg.
The calculation of the total mass of the load on the foundation: 25000 + 7350 + 8820 = 41170 kg.
This value must be multiplied by a safety factor of 1.1. We get 45287 kg.
Now it remains to divide the obtained value by the size of the load per one pile (for example, screw): 45287/2000 = 22.6435. After rounding, we get 23. This is the number of supports you need. Installation step – 1.2 m.
If the site on which you decide to build a house has a complex topography, then it is better for you to use a pile-and-foundation foundation. It consists of a tape (grillage) and piles. The technology of construction of this type of foundation is not particularly complex, so it can be done with your own hands. To perform this work, follow these rules:
- make markup. To do this, drive the rods into the corners of the future structure and stretch the cord between them;
- determine the location of the piles;
- Dig a pit under the tape;
- drill holes for piles on its bottom;
- install asbestos-cement pipes into the dug pits, filling about 30 cm of sand into them;
- arrange thorough waterproofing of piles using roofing felt;
- Install several metal rods into each pipe. Rods should rise 20 cm above the ground;
- fill each pipe with concrete, avoiding the appearance of air pockets;
- after the concrete has set, set the tape. For this, the bottom of the structure is laid out in 5 cm thick bars. Then a special grid is installed. Mesh elements are securely associated with reinforcement elements of supports;
- formwork is installed (wooden shields, which are strengthened by struts and struts). The formwork should slightly exceed the height of the future basement;
Helpful advice! To give additional reliability to the formwork walls, fasten them with stakes hammered into the ground (from the outer and inner side). Stake tops should be firmly tied with wire.
- concreting. It is necessary to pour concrete with periodic tamping, leaving no empty seats.
According to reviews, the pile-screw foundation is better to use for the construction of residential and non-residential premises on wet soils.
Calculate the number of piles needed by example. Initial data:
- pile diameter – 40 cm;
- the estimated mass of the house is 80 tons;
- soil bearing capacity – 5 kg / cm2.
The formula for calculating:
Fсв = (? D2 / 4) XR.
Load per pile: 3.14 (constant value) x 1600 (diameter squared) = 5024.
The resulting value is divided by 4 (constant number) and multiplied by the value of the bearing capacity of the soil: 5025/4 x 5 = 6280.
The required number of piles: 80t / 6280 = 12,738. Round the resulting value.
You need 13 piles.
Remember that for the correct construction of the pile foundation, the calculation of the number of piles is a necessity. Erroneous calculations will lead to the appearance of cracks in the house and the gradual destruction of its walls.
To build a house without a basement and a basement, you should opt for a screw foundation. It consists of piles that are screwed into the ground like screws. Not recommended for soil containing hard rock. How to install piles screw for the foundation with your own hands – the video clip will show more clearly. This video can be easily found on the Internet. The erection process consists of the following steps:
- determine the number of required supports and the magnitude of the load on them. The calculation of the load of screw piles for the foundation is made according to the formula: the area of the house is x (40 + 15xB), where B is the height of the facade of the building;
- we make markings on the land plot with the help of stakes and a cord;
- we drill pits for piles. Their diameter should be slightly smaller than the diameter of the blades of the pile;
- we establish support;
Helpful advice! Be sure to use the level to observe the strict vertical installation. If the support is not smooth – the foundation will not sustain the load.
- excessive length of the piles cleaned with grinders;
- weld the platform from steel to the cut edge of a support. The metal channel fastens on it.
Rostverk is the part of the foundation that rises above the ground surface. It is designed to distribute the load on the pile structure. For the manufacture of grillage using reinforced concrete or metal beams, which combine the piles into a single structure. To properly build the grillage, you must observe the following sequence:
- formwork is being built;
- fit fittings. It is carefully strengthened to avoid possible bias;
- concrete is poured. Make sure that there is no leakage beyond the limits of the formwork;
- air is blown out of concrete. This should be done with a conventional pin;
- ready grillage give time to harden. To do this, cover it with plastic wrap. During the week it is necessary to periodically remove the polyethylene and water the structure;
- then clean the formwork. Rostverk checked for compliance with the size and shape.
To build a durable and reliable house, you need to properly equip its foundation. Before construction, carefully read the basic bookmarks of the building and the basic rules of installation. Observing all the necessary technologies, you will perfectly cope with the independent construction of the foundation.