The basis of any structure is the foundation - it binds together the entire building, gives it stability and protects it from deformation. The choice of foundation is influenced not only by the parameters of future housing, but also by soil indicators (soil type) on the site. Very often, the behavior of the soil presents surprises that cannot be called pleasant.

Many standard projects are designed for any conditions (excluding, however, areas with permafrost). Such a margin of safety for the foundation is expensive and not always justified; it is more logical to order individual engineering-geological surveys. If the analysis reveals unstable soil, only the foundation on driven piles can become the basis for trouble-free construction and long-term operation of housing.

Foundation on piles - an excellent solution for unstable ground

About pile foundation

Building a house is a costly undertaking and many choose to cut costs by not doing any groundwork. Practical owners see geological work as an investment for the future, protecting against major disappointments. In floating, sandy, swampy and peaty soils (with high groundwater and low density), even an expensive monolithic foundation cannot be considered reliable. In such conditions, the choice of foundation for a private building is predetermined. In modern suburban construction, various pile technologies are popular. They are distinguished according to the following parameters:

Ways to dive

The method is chosen based on the results of geology and the design characteristics of the future home. To properly distribute the load, reinforced concrete piles for the foundation must be immersed to the depth of a dense, stable layer. Supports are deepened in different ways:

• Zabivny. Common method; driven piles are driven into the rock using a mechanism with a hydraulic or pneumatic hammer.
• Indentation method(using static pressure).
• Vibration penetration. Hollow shell piles are placed in place of the excavated soil, concrete is poured.

Various technologies for deepening supports

Driven piles for a private house are poured using one of the following technologies:

• Boronabivnaya. A formwork (for example, a pipe) is placed in a drilled well, reinforcing bars are installed, and concrete is poured.
• Buroinjection. A concrete mixture is fed into the well under pressure, then a reinforcing cage is installed.
• Ground-cement. A mixture of soil and cement is fed into the well. The content of cement, the cost and strength of such a pile is 2 times less than that of a cement concrete pile.

Types of supports

The choice of pile material is influenced by:

• The design load transferred to it during operation.
• Estimated life of the house.
• Support size.

In low-rise construction, supports are common:

• Reinforced concrete piles for the foundation. The most common and affordable option, capable of withstanding significant loads and designed for 70-100 years of service. Piles with a square section are used, reinforced with reinforcement, with one pointed end. Concrete with a water permeability of at least W and a frost resistance of at least F 150 is used for manufacturing.

A significant role of reinforced concrete piles in the reliability of the future home

• Steel. Installation of such products (screw) is quick and therefore quite attractive. Various rolled products (pipes, channels, rails) act as piles; they are used for small household buildings, the service life is limited to 40-60 years.
• Wooden. Gradually withdraw from mass use. Wooden products are justified in the construction of light buildings, whose service life does not exceed 30-40 years. They can be used in the construction of wooden and frame houses if they are made of hardwood (oak, pine, larch).

Online foundation calculator

To find out the approximate cost of a "grillage on piles" foundation, use the following calculator:

Foundation device on driven piles

In private construction, bearing foundations are used on reinforced concrete driven piles of two options - slab and tape. Slab foundations perform well on complex soils prone to horizontal movements. Tape base - standard for low-rise construction. They have a different area of ​​​​support, but with proper calculation they guarantee a stable position of a private building. Piles are installed in several ways:

• Single piles. Supports are placed at certain problem points.
• Rows. Piles are driven under future walls and partitions.
• field. This procedure is used for arranging a pile-slab foundation; pile field is less commonly used in low-rise construction.

Row pile foundation with grillage

On our website you can find contacts of construction companies that offer foundation design and repair services. You can directly communicate with representatives by visiting the exhibition of houses "Low-Rise Country".

Video description

What are the pros and cons of a pile screw foundation? Is it possible to make a quality foundation for little money? See in this video:

The principle of using grillage

The foundation on reinforced concrete piles is combined into a common structure with an upper part, a concrete strip (grillage). The installation of the grillage is carried out in several ways:

• High (hanging). There is free space between the bottom of the tape and the ground. The method is used in the construction of gazebos and baths.
• Unburied. The tape sinks into the ground to a shallow depth.
• Buried. The foundation gains additional strength.

Rostverk is not a mandatory element. In the construction of small lightweight structures (summer houses) in a hanging version, a lattice of profiled metal products (an I-beam or a channel) is often used. The metal is outside, the likelihood of rapid corrosion is reduced.

requirements for driven piles; calculation of their number

In practice, reinforced concrete piles of square or round section (from 200 to 300 mm) are most often used, with an end pointed on one side. High-quality products are made in workshop conditions from reinforced concrete.

The deviation of the pile axis from the vertical should not exceed 1 cm per meter of support

In order for the foundation on reinforced concrete piles to reliably cope with the load, the number of piles and the depth of their driving are preliminarily calculated, which can be from 3 to 10 m. To determine the parameters of the foundation, take into account:

• Soil type. Geological research will determine it most precisely, but you can also use a reference book.
• House weight. It is determined based on the materials spent on the construction (in cubic meters) and the mass of 1 cubic meter (table value). The weight of the roof, floors, concrete grillage and finishing materials is calculated separately. The weight of the furniture is added to the amount (approximately 7-10 tons).

Calculations are always carried out with a margin of safety, so the total amount is increased by 30%. Let the weight of the structure be 180 tons. A reinforced concrete pile 4 meters long holds an average load of 20 tons (for loamy soils); therefore, 9 piles will be able to evenly and safely distribute the entire load of the structure.

High-quality piles - the basis of the foundation with high technical performance

Advantages and disadvantages of using driven reinforced concrete piles

The foundation on driven reinforced concrete supports is used both for residential private houses (made of wood, brick and timber), and for household structures (arbors, bathhouses, garages, sheds, fences and summer kitchens). The basis for choosing driven piles is not only the problematic soil, but also the features of the relief (slopes, ravines, pits). The advantages of the foundation of driven piles are:

• Efficiency. Often they are the only suitable way (in areas with a slope, marshy). The only limitation is rocky soils.
• Speed. The foundation is erected in 1 day (it takes 5-7 days to equip a conventional foundation). Construction can be continued on the day of construction (after pouring the usual foundation, you can start building walls 20-25 days after pouring).

Video description

About the pros and cons of pile foundations in the video:

• Zero cycle economy. The minimum amount of excavation reduces the cost of the foundation by 20-25%. Concrete consumption is reduced by 20-30%; work can be carried out year-round, which will not affect the quality of the foundation.
• Load bearing capacity. high; the load on 1 pile reaches 40-50 tons. The strength is further enhanced by the grillage, which helps to distribute the load of the structure.
• Durability. Guaranteed service life of 100 years.

It is extremely difficult to organize a basement inside a pile field

The foundation on piles for a private house using driven technology has its drawbacks:

• Restrictions in the project of a private house. The presence of a pile foundation does not imply the arrangement of a basement or basement.
• Distance limit to the nearest building. According to the requirements of SNiP 3.02.01-87, there are restrictions on the use of a light hammer (weighing up to 7 tons) on a personal plot.
• Technical equipment. You can't do without specialized equipment.
• Research error. Careless geological exploration (or lack of it) sometimes results in foundation deformation.

Video description

About the pile-driven foundation in the video:

Pile-driven turnkey foundations

The foundation of reinforced concrete piles is a common design solution, suitable for construction on a site with uneven terrain and unstable soil. Ordering a turnkey foundation from a construction organization is beneficial for many reasons:

• Timing. The performance of work and the deadline for delivery are specified in the contract.
• Reasonable prices. The price includes the delivery of supports to the construction site and the use of a pile driver. After installing and leveling the supports, you can immediately proceed to the grillage device.
• Conditions. Territory preparation, marking and driving are carried out by experienced specialists, whose work is guaranteed.

Formwork for pile-grillage foundation

Price

The cost of transportation and driving of supports is offset by savings in material and time. For a house with an area of ​​200 m2 (Moscow region), the price for:

• Pile foundation. Installation of piles - 380-400 thousand rubles, tying with a grillage - from 750 thousand rubles, a comprehensive package (together with a reinforced concrete floor) - from 1100 thousand rubles.
• Monolithic slab. 1500-1600 thousand rubles
• Tape. 1600-1750 thousand rubles

The price for driving reinforced concrete piles depends on its size:

• Section 0.2x0.2 m, length 3 m - 6-7 thousand rubles.
• Length 4 m - 7.5-8.3 thousand rubles.
• Length 5 m - 8.5-9.5 thousand rubles.
• Length 6 m - 9.5-11.5 thousand rubles.

Video description

About the foundation with a grillage for a private house in the video:

Construction stages

After the conclusion of the contract and the determination of the parameters of the pile-grillage foundation, field work begins:

• Preparation. The construction site is leveled and cleared of debris, materials are brought up.
• Markup. The design position of the supports is taken out in nature using geodetic instruments (theodolite, level).
• Try. A test pile is driven in (the soil is assessed).
• scoringka. Driven piles for a private house are installed at the desired point, brought to a vertical position and immersed in the ground to the desired depth.

Trimming installed supports to one level

• Pruning. Using a level (a device for measuring relative heights), the upper parts of the supports are marked at the same height and cut off.
• Arrangement grillage. A formwork is assembled around the supports, in which the reinforcing skeleton is knitted and fixed; concrete is poured into the prepared form.

professional equipment

A few decades ago, the technology of arranging a pile-driven foundation was an expensive and cumbersome procedure. For country houses, alternative options were used - screw and bored piles, less reliable and durable.

Today, in private construction, a variety of wheeled and caterpillar pile drivers are used. They effectively cope with driving piles for foundations for country houses and cottages, using special hydraulic equipment. Such mechanisms do not deform piles and work on all types of soils.

A well-designed foundation can withstand a lot

Conclusion

The appearance in private construction of a foundation on reinforced concrete piles made it possible to create reliable houses of any size where it was previously impossible or difficult. The foundation on driven piles, equipped with modern technology and taking into account the characteristics of the soil, is able to serve as a reliable support for a country house of any type.

A solid foundation foundation is a guarantee of building stability even in soils with insufficient bearing capacity. The foundation on concrete piles can be used in problematic soils, including on weak foundations. Concrete piles for the foundation are made directly at the construction site, which reduces the cost of transporting structures.

Concrete pile classification

Piles are usually subdivided depending on the material of manufacture, so concrete support rods include reinforced concrete supports and concrete piles.

Reinforced concrete driven supports are usually manufactured industrially, concrete ones can be poured directly at the construction site, while the work on arranging a pile field under the building can be done by one's own hands. Installation of driven supports cannot be done manually; to immerse the rod into the ground, you will need to use expensive pile driving equipment, which greatly increases the cost of building the facility.

The disadvantage of driven piles is that they are mounted using special equipment.

Depending on the installation method, concrete supports can be divided into two groups: stuffed and driven.

Stuffed supports according to the technology of work are mounted in pre-prepared wells (pits), which are performed using special drilling equipment. Driving rods are immersed in the ground (sandy or clayey) without prior preparation.

It is customary to subdivide piles depending on the shape of the cross section, there are reinforced concrete supports with round rods, as well as square and rectangular ones. Round supports are used on weak, heaving soils, which are based on clay; for more rigid soil bases, rods with a square or rectangular section are used.

Piles are distinguished by the type of load received, the supports are divided into central and auxiliary. The central ones take on the entire load from the foundation belt, the auxiliary ones take only the load with eccentricity.

Bored piles

One of the types of concrete piles are bored supports. Bored piles are reinforced concrete structures, the installation of which (filling) takes place in wells specially prepared by drilling.

The bored pile consists of reinforcement strapping, shell pipe and poured concrete

The design of bored supports consists of two elements:

• Concrete core - frost-resistant concrete M200 and M300 is used to fill the support.
• Reinforcing steel frame - for the reinforcement of piles, ready-made frames made by an industrial method can be used, it is allowed to manufacture reinforcing frames directly at the construction site, for which smooth and corrugated reinforcement is used. The longitudinal bars of the reinforcing cage are made of corrugated reinforcement with a diameter of 12 to 20 mm.

Cross jumpers are made of a smooth bar with a diameter of 8 mm. The frame is welded using electric arc welding machines. The joints of the fittings must be carefully treated with protective compounds against corrosion.

To solve various construction problems, two types of bored piles are used: ordinary cylindrical supports and rods with a broadening of the support sole. Widening at the bottom of the pile (heel) is performed to increase the bearing area of ​​the pile rack. Such supports have increased stability and are able to carry an increased load from the weight of structures.

The support broadening can be formed using special drill strings, as well as using a specially prepared explosion.

The technology of building a foundation from bored supports

In frequent construction, piles with a non-removable shell are most often used.

When installing a foundation base from bored supports, several options for arranging a pile rod are used:

1. Pouring without shells - this option is used only in stable soils with a minimum level of groundwater. For arranging pits for supports without shells, it is important that the edges of the wells do not crumble, are not washed away by groundwater, and do not change their geometric shape. To strengthen the well, during drilling, clay or concrete mortar can be used, which reliably strengthen the walls of the prepared pits.
2. Installation of pile rods with a removable shell - this technology is used in water-filled soils. The casing pipe, made in the form of a cylinder of steel, prevents the collapse of the walls of the well and the erosion of concrete in the process of filling the cavity. After filling the pipe with concrete mixture, the casing is removed to the surface.
3. Filling piles in a bored way with a permanent shell (not retrievable) - this method is practiced when arranging foundation supports on soils with a high level of groundwater, composed of rocks with low bearing capacity, which can be eroded by groundwater during the concreting process.

Construction of the foundation from bored rods: stages of work

Before you concrete the foundation supports using the bored method, it is worth preparing the construction site. The territory must be cleared of construction debris and plant residues, if necessary, uprooting of old trees. With uneven terrain - plan the area with a bulldozer.

On the territory of the building, the places for immersing piles are marked. The distance between the individual posts is up to 3 meters long in stable soils. In problem soils (mobile, landslide, water-saturated, dusty, loess-like) - the distance is taken up to 2 m.

After completion of the marking work, wells are drilled at the indicated points with a special drill. For drilling, a special installation or a manual garden drill can be used.

Formwork (casing pipe) is lowered into prepared wells, for the manufacture of which plastic and asbestos-cement pipes are often used. A reinforcing cage is laid inside the formwork, the height of which should exceed the length of the pipe (outputs of frame reinforcement up to 15 cm are left above the surface of the piles if it is planned to build a foundation with a grillage).

Watch a video of how bored piles are poured for a private house.

It is possible to fill the formwork with concrete more than one day, so the labor intensity of the work is reduced. After the concrete mixture has hardened, the grillage is started. On the foundations of bored piles, a rigid grillage belt made of concrete is provided.

If the supporting base is being erected on heaving soils, the grillage tape should be raised above the soil surface, this position of the structure will prevent its destruction when the soil moves under the influence of frost heaving forces. A house built on piles is characterized by increased stability, strength and durability.

The article describes the technology of pile foundation using a drill. After reading, you will understand how to make a pile foundation, find out the disadvantages of a pile foundation, difficult moments and important aspects of construction.

Pile foundation technology

If we compare the technology of a column foundation, which requires digging holes with slopes, arranging formwork, then filling up the sinuses, then the technology of a bored pile foundation is more technologically advanced. In general, it involves drilling a well of the estimated diameter, installing reinforcement in it and pouring concrete into the created well. A big plus of this option is that the well can be drilled with a manual construction drill.

Let's look at this technology in more detail.

Drilling of the wells

The number of main bored piles (along the perimeter of the building) is determined based on the weight of the future house along with the operational load. The parameters of internal piles are determined based on the loads created by the floor, partitions, roofing and operational loads.

When calculating, it should be remembered that the maximum diameter of a hand drill that can be used manually is 300 mm, such drills are commercially available in a large assortment. The length of the drill rod is adjustable, which allows you to drill holes up to 5 meters or more. The cutting blades of the drill are arranged in such a way that the applied force during drilling is minimal. Now construction drills for manual drilling with a device for significantly widening the lower part of the well are commercially produced. In this case, a bearing foot is formed for the pile, which can significantly reduce the number of piles and, as a result, save concrete.

Note: If you have a need to drill holes with a diameter of 500-600 mm, the effort applied for this is quite large. To drill such wells, the industry produces electric and motorized drills. For example, an electric pit drill, used for drilling wells for the installation of high-voltage lines, allows you to get wells with a diameter of up to 1 m and a depth of up to 4 m. There are also drilling machines based on cars, wheeled tractors.

Concreting and reinforcement of piles

Below we will consider how to perform concreting and reinforcement of bored piles, the installation of a grillage on bored piles

After the wells are drilled, “pipes” should be made of roofing material along the diameter of the well and 200-300 mm longer than the depth of the well.

The upper part of the "pipe" should be made of 2-3 layers of roofing material and pulled together with soft steel wire. This part will serve as formwork. Then the “pipe” is carefully inserted into the well.

If there is a small amount of water in the well at the bottom, then you should not pay attention to it, but if it is more than 1/4 of the depth of the well, then it should be pumped out before pouring concrete.

If such a “pipe” is not used, then this can lead to negative results that affect the strength of the foundation pillars:

1. when setting concrete and gaining its strength, the presence of "cement milk" in the concrete mass is of great importance, and it can easily go into the ground and not get the design strength;
2. when the soil freezes, the forces of frost heaving will act much stronger on the rough walls of the pile obtained by pouring concrete into a well without a “pipe” than smoother ones using a “pipe”.

When the well is ready, to increase the strength of the pillars, it is necessary to make the simplest and most inexpensive spatial reinforcement cage. Enough 3 vertical bars Ø 6 mm from reinforcement, fastened together through 500-600 mm crossbars. To connect the pillars with the grillage, vertical rods must be brought above the poured piles to a height equal to the height of the grillage minus 2-3 cm.

It should be noted that with heaving soils, the grillage should “hang” on piles at a height of 150-200 mm from the soil surface, for which a pile protruding from the ground is made (soil heaving can reach 15 cm in moisture-saturated soils).

After the frame is installed, concrete is fed into the well in layers (40-60 cm), while it is compacted using vibrators.

grillage device

Grillage on piles is carried out both from precast concrete elements (beams) and monolithic.

Examples of conjugation of the heads of round stuffed piles with a prefabricated and monolithic grillage: a - conjugation of elements of a reinforced concrete prefabricated grillage (beams, lintels) with a stuffed pile head; b - pairing of a monolithic reinforced concrete grillage (belt) with the head of a stuffed pile.

1 - stuffed pile, 2 - reinforced head made of monolithic concrete, 3 - prefabricated reinforced concrete grillage, 3 (dash) - monolithic reinforced concrete grillage, 4 - assembly joint between the prefabricated elements of the grillage (performed with fine-grained concrete M200), 5 - reinforced rod d 18- 22 mm with a short piece (cut) welded to it 20-25 cm, reinforcement d 18-22 mm, 5 (dash) - reinforcing bars for pairing the pile head with a monolithic grillage, 6 - pile cavity (filled with concrete), 7 - steel embedded part with welded plate.

• height - not less than 300 mm;
• the width with a single-row arrangement of piles is taken equal to the width of the plinth, and in the absence of a plinth - the thickness of the walls of the first floor, but not less than 400 mm.

Attention! Crossing (cutting) the grillage with sanitary and other pipelines is not allowed. The deviation of the centers of the piles from the vertical position (checked by a plumb line) after immersion or concreting should not be more than 5 cm.

When installing the prefabricated elements of the grillage, special attention should be paid to their fastening on the pile head. To do this, in the process of filling the cavity of the stuffed pile with M200 concrete mixture, a T-shaped reinforcing bar 5 is concreted vertically. Another reinforcing bar is laid horizontally on the pile head. Its length should be equal to the width of the pile with limiter plates welded on both sides. Their height should be sufficient to capture the pile and the mounted element of the grillage. Then the mounting joint 4 is concreted, and the short vertical rods 5 are welded to the grillage mounting loops using reinforcing bars of the required length.

In the case of replacing the prefabricated grillage beam with prefabricated reinforced concrete bearing lintels, they must be fixed to each other by welding using reinforcing bars or tied with wire twist.

After the grillage is installed, all joints and seams are filled with fine-grained concrete or cement mortar. Before erecting the walls of the house, the marks of the upper planes of the grillage are checked and, if necessary, leveled with cement mortar under one mounting horizon (horizontal level with the same marks). To do this, in the absence of a level, you can use the water level. The final check of the squareness of the plan and the dimensions of the grillage is performed by measuring its diagonals and sides.

Limitations in the use of pile foundation

Pile foundations also have disadvantages, or rather restrictions that prevent their use, namely:

• pile foundations are bad in horizontally moving soils (these include swelling, subsidence soils, the specificity of the soil can only be determined by laboratory research, for which a detailed geological study will be required) due to insufficient resistance to overturning - in this case, a rigid reinforced concrete grillage is required;
• when arranging pile foundations, difficulties arise with the construction of the basement. It is necessary to fill the space between the piles (perform a pick-up) in the same way as in the design of a columnar foundation. And this is an additional cost of effort and money. See the article on our website for more details.

The cost of building a pile foundation

The pile foundation of a country house can be made of various materials, depending on them, the price of the pile foundation varies.

Estimated price of the foundation of bored piles:

• for a house 6x6 from 9000 UAH or 1150 c.u. ;
• for a house 6x9 from 14000 UAH or 1800 USD;
• for a house 9x12 from 26000 UAH or 3300 USD

Examples of the use of pile foundations in private construction

Example 1 An order was received from a private developer to develop a project for a 2-storey cottage with brick walls. According to the results of geological studies, it was found that the top layer of soil (to a depth of 2 - 3 m) is silty soils with peat inclusions. Below was a layer of dense sands. Due to the inability of silty soils to carry the calculated loads, it was not possible to arrange strip or column foundations. The developer proposed a variant of the pile foundation. In this case, the piles (piles-pillars) must rest on the sand. The piles were driven through silty soils into dense sand to a depth of 0.5-1.0 m.

It turned out a reliable and durable foundation.

Example 2 When ordering a project for a country house, one of the customer's requirements was to provide for the minimum cost of building materials for the construction of the foundation. Geological studies have shown that existing soils are able to carry the load from the house in the form of strip or column foundations, and even with a margin.

Based on the requirements of the customer, a variant of bored piles was proposed, which was implemented. As a result, a high-quality, durable foundation was obtained with significant savings in concrete and minimal earthworks.

Read an overview of the types of foundation for a house in the article.

Note: Prices are for 2009.

In contact with

Classmates

The boom in construction in recent years, both low-rise private and high-rise, requires contractors to use a variety of construction methods.vis

The choice of method depends on climatic conditions, terrain, soil types.

It is especially important in construction to use technologies that will allow the building to perform its functions for many years. And in this matter a huge role belongs to a well-built foundation. There are many types of foundations today, this is due to the variety of soils on which construction is to be carried out, and ultimately, the strength and stability of the structure depends.

One of the most reliable is the foundation on driven piles. This type of foundation has been used for many centuries. for the construction of buildings on unstable soils.

A driven pile is a reinforced concrete rod, usually of square section, sizes from 150 to 500 mm and lengths from 3 to 25 meters.

The process of hammering by hand is not possible; for this, special hammers are used, usually hydraulic, installed on special construction equipment.

One end of such a support is pointed for better penetration into the ground. The length and section are calculated individually and depend on the type of soil and the mass of the building.

Important: Anyway, the lower end of the supports should rest against solid ground. Only in this case, the foundation will withstand the pressure of the house, and when the soil is heaving, it will remain motionless.

For example, when building a one- or two-story frame house on loamy soils that prevail in our country, it is enough to use driven reinforced concrete piles 3-4 meters long and 150-200 mm in diameter.

Foundations on driven piles can be slab and tape type. In the first case, the area of ​​​​support on the ground is maximum and this type is most reliable on unstable soils. The tape type has a smaller footprint, but still sufficient for a stable position of the building.

The device of the foundation of driven piles involves them installation:

• in the form of a pile field, when using a pile-slab foundation, mainly for the construction of multi-storey buildings;
• in line. In this case, the supports are clogged in rows, under the future walls of the building, always at the corners and intersections of the walls at a certain distance from each other. This method is used in low-rise construction and construction of frame houses;
• in the form of single supports installed in the most problematic, in terms of soil heaving, places.

Application

It is recommended to build a pile foundation if it is necessary to transfer the load of the finished structure to unstable ground. It is advisable to use it on swampy and peaty soils. when an incompressible dense layer of soil is at a sufficient depth.

The required number of piles, driven to the depth of stable soil, combined into a single structure with the help of a grillage, will be a reliable support for a frame house of any type.

Reference: it is worth noting that more than 60 percent of all multi-storey buildings are built on foundations using driven piles. This only confirms the reliability of foundations of this type.

Types of driven piles

In low-rise construction, including in the construction of frame houses, the following types of piles:

1. Reinforced concrete. The most common type. Widely available in any locality, many organizations are engaged in the production and installation of reinforced concrete piles. Service life from 50 to 150 years. They may differ in several ways:
   • piles with prestressed and non-stressed reinforcement;
   • round, square, tee and hollow section;
   • prismatic and cylindrical;
   • monolithic and prefabricated (composite);
   • piles with an expanded, shackled or hollow heel.
2. Wooden. Most often used in the construction of wooden log cabins and frame houses with a wooden base. They can be made from some types of wood, they are less reliable, but in individual construction they are often used on heaving soils. Such piles are usually made of oak, larch, cedar, and other hardwoods. Wooden piles are used with a diameter of 20-40 cm, a length of three to 8 meters. When used on hard soils, the lower pointed end of the pile is equipped with a steel tip with a strapping shoe. The service life of a foundation on wooden piles depends on the climate and soil in a particular area, but, as a rule, is at least 50 years with proper operation.
3. Steel. They can be made from various rolled products - channel bars, rails, pipes, etc. They are used quite rarely, mainly for temporary structures, or outbuildings. Approximate service life 40 - 60 years.

Calculation

In order to have confidence in the reliability of the pile foundation during the construction of the structure, it is necessary to correctly calculate the number of piles and the depth of their driving.

Depending on the type of soil, during the construction of a frame house, the pile driving depth can vary from three to ten meters, and the section size from 150 to 250 mm.

Important: you can find out exactly the type of soil prevailing in a particular area using specialized reference books, or this can be done by a special organization.

Let's give an example of calculating a pile-driven foundation for building a two-story frame house on loamy soils, which occupy about 80 percent of the territory of our country.

For example, it took 60 cubic meters of larch timber to build a house. The mass of one cubic meter of semi-dry (namely, this is suitable for construction) larch is about 800 kg. By simple multiplication, we find out that the total mass of the log house will be about 50 tons.

Let's add here a lot of floors, roofs, finishing materials and do not forget about the concrete grillage. By the same calculation in terms of volume, we find out that this is about 80 tons more. And, lastly, this is a mass of furniture, and everything that will be in the house. We get about 10 tons.

Summing up the results, we get the total weight of the finished structure in the region of 140 tons. Let's add 30 percent of the reserve for reliability and get 182 tons.

The pressure that one reinforced concrete pile 4 meters long holds is from 10 to 40 tons, depending on the soil, according to all engineering manuals. Taking an average load of 20 tons per pile, it is easy to calculate that in this case, only 9 piles are needed, hammered in compliance with all norms.

On practice same, for the construction of a frame house, driven reinforced concrete piles for the foundation are hammered with a distance of no more than 2.5 meters for a more uniform load of the structure on the grillage.

For your information: in this way, it is possible to carry out a calculation for any terrain and any type of piles.

Construction stages

So, all the materials are selected, the necessary calculations are made, you can start building:

1. The first stage is carried out land clearing for pile driving and delivery of materials. It is necessary to remove the sod and topsoil.

2. Implemented marking the future foundation, and places for driving piles are planned.

3. When it's all laid out, one more time level and geometry are checked future foundation.

4. Happens by itself the process of driving piles using a machine with a hydraulic or pneumatic hammer. In the process of immersing the pile, it is necessary to monitor the observance of a strictly vertical level of the pile. In addition, experienced craftsmen necessarily notice the non-standard behavior of the support when immersed, if it stumbles upon an obstacle or, on the contrary, “sinks” in underground voids. In this case, the support is lengthened, or moved a little to the side.

5. After all the supports are immersed in the ground, it is necessary chip off the top of the pedestal in order to gain access to the armature and align all supports at the same height.

7. In the case of a pile-strip foundation, a reinforcing cage is made in the formwork and poured with mortar. After 28 days, the foundation is ready for the construction of the building.

Manufacturing grillage

The grillage is a part of the foundation structure, which connects the supports into a single structure and is a support for the walls of the building. Not a required element. But the foundation on driven reinforced concrete piles with a grillage is more stable and stronger than without it.

Peculiarities: it is allowed not to build a grillage if the structure is made of timber. In this case, the role of the grillage is played by the lower crowns of the building itself.

Can be done metal or reinforced concrete.

In the first case, finished metal products are used, usually a channel, an I-beam or a rail. They are laid in level on hammered piles and welded to the reinforcement bars emerging from the supports. The elements are connected to each other by welding or bolts. This type of grillage is great for temporary or non-residential buildings, such as attics, bathhouses, summer arbors.

Reinforced concrete grillage is made by pouring the solution into the finished formwork with pre-laid and fixed reinforcing mesh.

Rostverk happens three kinds:

• hanging. Located at a decent distance from the ground, the space under the floor is not isolated. It is used in the construction of baths, attics, seasonal country houses;
• shallow. It plunges to a shallow depth in the ground. They do not serve as a support, they are designed to protect the underground space of the house from drafts and bad weather;
• buried. For its construction, a trench is dug by analogy with a strip foundation. It is an additional support for the construction, strengthens the pile foundation, is excellent for the construction of a capital all-weather frame house.

Advantages and disadvantages

We advise you to study before building a foundation from driven piles: the pros and cons of this foundation, based on many years of operating experience.

Advantages:

1. Pile supports allow you to produce construction on any type of soil, except rocky. With a length of up to 40 meters, the supports transfer the load of the structure to dense bearing layers, which allows you to ignore all the inconveniences of unstable soils.
2. Piles are highly resistant to adverse climatic conditions, their service life reaches 150 years.
3. Thanks to reinforcement, pile supports withstand not only vertical, but also horizontal loads, which is especially important when used on "floating" soils.
4. Construction of a pile foundation does not take much time. One support 4 meters long is deepened within a few minutes.
5. Minimum excavation work and use of building materials.
6. Work on the installation of a pile-driven foundation can be carried out all year round and in all climatic conditions.

disadvantages a pile-driven foundation has a little:

1. Despite all the calculations, there is always a possibility misjudgment of the soil, since there is no way to see what is actually at a depth of many meters. As a result - sediment or skew of the foundation.
2. For driving piles, it is necessary to use special equipment.
3. Difficulties in the construction of the basement or underground garage.

Useful video

Visually familiarize yourself with the process of driving piles of different sizes and, accordingly, different techniques in the video below:

conclusions

Taking into account all of the above, we can conclude that a pile-driven foundation is the most reliable option for a private house, as well as for the construction of buildings of any type, in almost any area. Its many years of experience in all types of construction is a good proof.

Recently, many organizations are engaged in the production and installation of piles for minimal amounts comparable to the construction of foundations of other types, thereby ensuring accessibility and prevalence.

In contact with

The device of the pile foundation makes it possible to build buildings on problematic soils characterized by low strength, weakness, heaving, and a large freezing depth. Piles ensure the reliability of the structure. They transfer loads to stronger soil layers, which are located below the problem areas.

Pile construction

Piles are long rods that are immersed in the ground in finished form or are made in the ground itself. They have a pointed end. It is hammered into the ground with the help of special equipment. According to the method of immersion in the ground, pile structures are of various types:

1. Driven piles. Their immersion in the ground is carried out using vibrators.
2. Concrete and reinforced concrete stuffed piles. They are created by drilling wells and then pouring concrete.
3. Drilling reinforced concrete piles. They are created by installing concrete elements in a drilled well.
4. Screw - installed by twisting into the ground. Their design is in the form of a drill.

The design of piles differs in the way they act on the ground. So, the following types are distinguished:

• hanging piles, in which the load is transferred by friction of the soil on the surface of the piles;
• pile-racks, the principle of transferring the load in them occurs on solid ground, which is located under a layer of weak soil.

The design of piles is determined by the principles of placement in the ground. So, piles can be:

• single, which act as separate racks;
• combined into large pile tapes, which are located along the perimeter and distribute the load evenly;
• combined into pile bushes, which are located under the columns of the supporting frame frames of structures.

The following materials are used for their manufacture:

1. Reinforced concrete. Reinforced concrete piles can be made on site if the appropriate machinery is available. For the implementation of such piles, concrete grade M200 is used. The service life of these piles is more than 100 years.
2. Steel. Such piles have many disadvantages. They must be installed with a crane. The metal must be carefully treated with an anti-corrosion coating. The production of such piles takes a lot of metal.
3. Tree. Piles made of wood are even pillars up to 8 m long and up to 30 cm in diameter. For piles, species of hard coniferous trees are used - pine, fir, spruce, larch. Wooden piles are cheaper than steel or reinforced concrete, but they are rarely used due to the fact that wood is prone to destruction. When using preparations for treating wood from destruction, this method is also used.

For suburban private housing construction, reinforced concrete piles with a solid section, steel screw and concrete stuffed piles are the best option. The most acceptable option for deepening is the bored method.

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Pile foundation design

What is the foundation structure? The pile foundation consists of shells or piles and a beam or slab that unites them from above, called a grillage. The grillage takes the load from the structure located above it and distributes it among all the piles.

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Pile foundations types

There are a large number of different designs of pile foundations. There are types of pile foundations with high or low grillage.

In a high grillage, the sole rises above the ground, and a low grillage is buried in the ground.

The design of a foundation with a high grillage has significant advantages over a deep foundation with a low grillage.

Advantages of foundations with a high grillage:

1. With the same rigidity and bearing capacity, their construction takes less labor and materials.
2. It is not necessary to carry out excavation work on the construction of a pit in the ground.
3. Cheaper lintels of different designs can be used instead of sheet piling of pits.
4. Precast concrete slabs can be used instead of cast-in-situ slabs that are concreted in place.
5. Shells and pillars are used more efficiently.
6. The erosion of the bottom of the channel is reduced.

According to the type of load-bearing elements, pile foundations are divided into foundations made of piles, shells and pillars. You can create slanted foundations. At the same time, in terms of their bearing capacity and rigidity, they will be equivalent to foundations with a slab buried in the ground.

1. They can be arranged on weak soils with low strength, large freezing depth, heaving and compressibility.
2. Piles transfer loads to deeper solid layers of soil and thus provide the structure with strength and durability.
3. Many pile foundation designs can be installed with reduced earthwork and concrete work compared to other types of foundations.

1. They cannot be installed in horizontally moving soils, namely in subsidence and swelling soils due to their insufficient resistance to overturning. In such conditions, it is necessary to install a reinforced concrete grillage.
2. In the manufacture of pile foundations, difficulties arise with. In this case, it is necessary to fill all the space between the existing piles.
3. A large number of mechanisms and labor costs are required. Relatively high construction cost.

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Pile foundation construction technology

The technology of building a pile foundation involves drilling wells, installing reinforcement and pouring concrete into the well.

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Foundation device

Materials and tools:

• reinforced concrete piles;
• reinforced concrete beams for grillage;
• reinforcing bars with a diameter of 6 mm;
• roofing felt pipes;
• steel wire;
• cement, sand;
• yamobur;
• manual drill;
• vibrator;
• construction plumb;
• level, water level.

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well drilling

First, a well is drilled with a manual construction drill. determined depending on the weight of the future building. The design of piles is determined depending on the loads from partitions, roofs, floors and operational loads. The maximum diameter of the used hand drill is 300 mm.

Builders drill with minimal effort due to the improved positioning of the drill blades. The length of the drill rod can be adjusted. This allows you to perform wells up to 5 m deep. You can use a drill that has a device for widening the lower section of the well.

This creates a support heel for piles. This reduces the number of piles and saves concrete. If it is necessary to make wells of a larger diameter, then quite a lot of effort must be applied. To drill such wells, motorized, electric drills are used.

For example, an electric hole drill is used to drill wells for power transmission line supports. In this case, wells up to 4 m deep and up to 1 m in diameter can be drilled. Drilling machines based on a wheeled tractor and trucks are also used.

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Reinforcement and concreting of piles

It is necessary to perform reinforcement and pour concrete piles.

After the wells are completed, it is necessary to make pipes from roofing material corresponding to the diameter of the well. Their length should be 200 mm greater than the depth of the well.

Then the upper part of the pipe is made of two layers of roofing material and pulled together with steel wire. This is how formwork is done.

After that, the pipe is installed in the well. Moreover, if there is water at the bottom of the well, it must be pumped out before pouring concrete.

Proceed to the implementation of the reinforcing cage. To do this, take three vertical reinforcing bars with a diameter of 6 mm and fasten them to each other with crossbars every 500 mm.

Vertical rods for connecting the pillars with the grillage must be brought above the piles poured with concrete to a height that corresponds to the height of the grillage minus 3 cm.

In heaving soils, the foundation grillage should be on piles at a height of 200 mm from the top of the soil. To do this, the piles are made protruding from the ground.

In moisture-saturated soils, heaving can reach 15 cm.

Then you need to fill the piles with concrete.

After mounting the well frame, concrete is laid in layers of 60 cm. Each layer is compacted with a vibrator.