Distance between piles in a pile foundation. Distance between screw piles. All about calculating supports: distance between piles

18.12.2022

Construction of a foundation without excavating soil and laying concrete is possible if you use screw piles. You won’t win money, but you’ll save at least six months of time: the concrete base needs to settle, preferably overwintered, in order to identify defects if the pouring was carried out in violation of the technology.

From the developer frame house time is constantly running out. Forming a pile field in a working day using mechanized screwing is a common thing. On a hillside, conventional measurements with a tape measure lead to errors: the distance between the points of the zero mark must be in the same plane.

And putting the frame offset relative to the grillage requires additional work: either adjust the size of the wall to fit the error, or remove the supports and drill with screw piles of larger diameter 1.2 m deeper.

How to choose the right piles?

In building a house, the strength and bending of each nail is not calculated. There are proven standard solutions. Design standards contain calculated and experimentally obtained solutions. Let's use ready-made recipes.

Determine the bearing capacity of the soil

Let's decide on the type of construction. The only difference between an all-season cottage for permanent residence and a country house is the thickness of the walls. It is ideal to have a project at hand, adapted to the given area, taking into account the soil structure based on geological surveys.

Even if it is not there, there are no hopeless situations. Information will be shared by the Internet and neighbors. But having received the necessary data, begin to drill a test hole at the lowest point of the site. An ice drill will help out for winter fishing with unusable sharpened knives. You will get a complete idea of humidity, horizon depth and composition.

It is advisable to drill the depth below the planned point of laying the foundation of the house being built. The qualitative indicators of the soil lying at the depth of the planned fixation of the tip are the ones we are looking for, which we will use for all calculations. Upper horizons do not play a role.

According to the bearing capacity, according to the degree of increasing bearing capacity, the soils in the table are arranged in the following order:

Bulk soil;
Sandy loam;
Loam;
Fine sand;
Sand of average fraction;
Coarse sand;
Clay.

Humidity reduces performance by 20–50%

Type and size

Let's take advantage of other people's experience. For the foundation of a frame house, regardless of the area and number of floors, supporting auger or screw elements with a trunk diameter of 108–133 mm and a supporting platform of 300–350 mm, respectively, are used.

When drilling and operating a building, the load falls on the screw. Based on this, we make a choice.

The photo shows an unprocessed workpiece. The seams will be cleaned, fillets will be formed along the leg of the seam, however, we advise you to opt for a cast tip: the only weld is located on the pipe and is not actively exposed to abrasives. The smoothness of the spiral is not affected by deformations and internal stresses resulting from the melting temperature of the metal during welding.

Important: welded seams are most vulnerable to corrosion, especially in places of periodic migration fluctuations in groundwater levels.

Corrosion damages cast steel less. Even complete destruction of the weld at depth does not weaken the foundation: the collar between the pipe and the tip will maintain connection with the load-bearing spiral. The integrity of the connection system between the grillage and the piles will not be disrupted even in such an event.

Support depth

Four main factors determine the degree of deepening: soil characteristics, water content, freezing depth, and the weight of the house. The tip support helical area cannot be located at or above the frost depth level. You need to have at least half a meter of reserve for a frosty winter with little snow.

It is impossible to artificially compact the soil under screw piles.

You will have to get to the dense layer or select piles with several support platforms. The increase in load-bearing capacity occurs due to a larger support area at several levels. The distance between turns is not regulated.

How many supports are needed?

Let's calculate the mass of the house in parts. The main building is separate, the extensions with non-permanent walls are separate. The ceilings and walls represent a layer cake: layers of basalt wool between wood and slab cladding.

We can’t take into account every board, let’s use the tabular data:

Insulated wall 200 mm – 70 kg/m2;
Interior partitions with sound insulation – 35 kg/m2;
Wooden interfloor ceiling – 180 kg/m2;
Roofing – 80–160 kg/m2 (Differences in the weight of roofing material);
Foundation piping channel 20P – 18.4 kg/linear m;
Pile Ø 108, L – 2.5 m – 30 kg;
Plumbing equipment – up to 3000 kg;
Equipment and furniture – 160 kg/m2;
Stove, fireplace or heated floor screed;
Snow load – climatic features of the region.

The calculated static load for a foundation with screw piles is 5–7 tons per Ø 108 pile on dense clay. And only 2.1 tons for sandy loam and loam. It is necessary to take into account the heterogeneity of the soil and the inevitable errors in verticality when screwing in manually. For practical reasons, the minimum design load is taken with the addition of a 30% safety margin.

Light-weight fragments of the house: verandas, terraces, garages will receive a foundation with piles Ø 89 mm. Excessive strength on these objects will affect the unloading of neighboring supports. And savings on building materials. It’s not difficult to find a calculator for the number of piles on the Internet.

Pile distribution step

The maximum permissible distance between piles for a frame and timber house is 2.9 m.
An increase threatens a loss of stability. Minimum – 0.5 m of solid soil without signs of integrity damage: loosening. In our case, 0.8 m between the axes with mechanical deepening. Failure to comply with this condition will exclude this pair of piles from supporting the grillage.

The corner supports of the foundation know their place. Others are installed either in parallel rows or in a checkerboard pattern. External ones go along the perimeter, copying the geometry of the house. The distance between them can fluctuate without going beyond the norm. Supports of smaller diameter for lightweight building elements are included in the overall scheme.

The optimal distance between piles is 6D (D is the diameter of the pile blade).

Sharp deviations are fraught with overstressing of the supports and grillage. In this case, each of the piles begins to work independently, perceiving the load not as part of a single integrated system, but individually. Deformation of the grillage, subsidence, and then destruction of the house and foundation, where the distance between the piles is critically overestimated.

foundation determined by the total load of the building on the foundation. The distance may vary, it all depends on the foundation design, but cannot exceed three meters - this is a critical distance.

The distance between screw piles is no more than 3000 mm.
Based on the foundation design, the distances between the load-bearing supports also vary. For a heavier structure, it is worth reducing the distance between the piles. A distance of 150 cm between the piles will be sufficient even for a building constructed from aerated concrete installed on a channel mounted on screw piles. But do not forget about the diameter of the piles for each specific structure. The more pile diameter, the more the ability to carry a larger load increases, therefore it is possible to increase the distance between the piles, of course without compromising reliability.

Minimum distance between screw piles Can be any determined by the foundation design but not more than 30 cm.
When choosing a foundation, you should consult with specialists and agree on all the details of the project.

The following are screw piles with load-bearing capacity:
for Ø57 mm – 1.5 t
for Ø89 mm – no less than 3.5 t
for Ø108 mm – no less than 4.5 t
for Ø133 mm – not less than 7.0 t
for Ø159 mm – not less than 10.0 t
Each the screw pile carries the load proportional to the total mass of the building.

taken from the total weight of the future building and divided proportionally by the number of piles, taking into account their load-bearing capacity.

The distance between the piles for the fence supports may vary but should not exceed three and a half meters. Although options for a larger distance between the fence piles are possible, for example, if the piles are not rigidly linked into one structure, each pile works separately. An example of this is the mesh used as a fence. The diameter and height of fence piles can also vary, it all depends on the design of the fence, its size, materials used, the quality of the soil and its saturation with water, design and connections.

Correctly calculated design and selection of piles and materials guarantee a long service life of the structure. We have extensive experience in installing fences and enclosures; we will help you determine the amount of materials needed and calculate what is needed number and size of piles.

Distance between screw piles for foundations with complex contours

When installing screw foundations with a complex contour(with a large number of corners for bay windows), a screw pile should be installed under each corner.

Screw foundation for a house with a bay window

This installation method preserves the integrity of the structure and evenly distributes the load over the entire area of the foundation. Regardless of the size of the porch, piles must be installed under the protruding parts. This will not cause unwanted drawdowns in the further operation of the structure.

It is especially necessary to install piles at each corner when installing a channel on them. The distance between intermediate piles should not exceed three meters.

You can get advice and order a foundation by calling us 981-84-08

Screw pile pitch

As can be seen from the above, the pitch (distance) between the screw piles is selected based on the necessary requirements for each structure.

Screw foundation calculation- how to produce it correctly? How many and what kind of piles should be used?

Calculation of screw piles for a house produced for each specific foundation. Calculation factors include; the total weight of the future building, the condition of the soil on the site, the landscape of a particular site, the configuration of the walls of the house, the presence of points of maximum load - (stoves, fireplaces, tanks and liquid containers, other possible heavy elements that exert significant pressure on the piles. But it is important to consider that three meters between the piles is the extreme distance. When constructing fences based on screw piles, the step between the piles is arbitrary, provided that the piles do not experience heavy loads during operation. For example, chain-link mesh and similar lightweight materials.

calculation of screw piles for a house

Distance between screw piles

Which distance between screw piles leave? Choosing the necessary step is not difficult, especially for light summer cottage buildings such as frame houses, which have become increasingly popular lately. It is important to consider that it is necessary that all parts of the building structure rest on their weight distribution points. It should not be when part of the structural elements of the building “hangs” in the air and does not rest on the intended point on the screw pile. Consequently, other piles will experience an increased critical load, which in turn may possibly lead to negative consequences. Arrange construction on pile foundation it is necessary so that the weight is distributed evenly; if the design features or defects are such that they do not allow contact transfer of the payload onto the pile, then it is necessary to provide an intermediate connecting element between the elements of the structure and the foundation; such materials can be wood or metal. Each pile takes on the design load of the entire building, and the snow load in winter is also taken into account. When tying a pile field with a channel or other heavy material (concrete strip, slab), it is necessary to take into account this load on the screw piles.
As described above, the distance between screw piles should not exceed three meters, especially for frame houses. where a distance of more than 3 m causes the timber or board to sag.

Distance between screw piles for a frame house

Distance between screw piles for frame houses may vary based on the features of architectural solutions during design. Piles must be installed in the places of the castle connections of the first crown of the building, at the corners of the bay windows, in the places where the logs should lie. It must be remembered that what more piles in the “field” of the foundation, the greater the load the foundation can support and vice versa. Also, soil and terrain features can influence the number and distance when placing piles. Areas with a strong slope, swampy, heavily flooded in lowlands require the use of a larger number of piles when constructing screw foundations, this is especially true for swampy soils with a large layer of peat and mobile soils, using a power frame in the form of channel piping and other binding steel materials.

Foundation under frame house calculated from the total weight of the house (including all materials used), including the possible snow load in the winter.

A good solution would be to use screw piles for the foundation of a frame garage. Moreover, the construction of such a foundation is made both using a channel in the form of load-bearing beams under the floor, and timber capable of holding the load, we assume Vehicle. In these cases, when calculating the number of piles for the foundation, the additional weight of, for example, a car is taken into account.

Foundation for a frame bath calculated with the possible weight of the stove, filled water tanks, chimney and other possible loads.

Pile foundation for a frame house using screw piles in its construction allows you to quickly and fairly inexpensively prepare the foundation for the future structure and begin further work in a short time construction work. A screw foundation for a frame house is perhaps the most practical solution given the choice.

Which foundation is better for a frame house?? This question is often asked before construction begins. Of course, our recommendations are a pile screw foundation for a frame house. Of course, if the conditions on your site allow you to install screw piles.

What is the best way to make a foundation for a frame extension? If the main building stands on a pile-screw foundation, then it is reasonable to “place” the extension on screw piles.

Foundation for a frame house price? It all depends on several components, these are the size and weight of the house itself, the architecture of the building, the quality of the soil, the topography of the site, remoteness, and the availability of electricity and water on the site. The foundation for a frame house is calculated based on these criteria.

What kind of screw piles are used for the foundation of a frame house? Any diameter from 89 mm. based on the requirements and required length.

The foundation for a one-story frame house is arranged as for any building with the obligatory calculation of loads.

Calculation of foundations on screw piles primarily produced from the total weight of everything and the features of a given building.

The technology for constructing a foundation based on a pile structure is considered one of the most reliable and practical. It can be considered universal, since the flexibility of the system and the variety of approaches to the technical implementation of the framework satisfy the requirements of a wide range of buildings. Among them residential buildings, industrial buildings, communication structures and other facilities. However, to achieve reliability of the pile structure, it is necessary to accurately determine the backfill parameters. In the list of the most important of them, experts note the distance between the foundation piles, which can vary depending on a number of characteristics of the building and construction conditions.

A pile structure can be represented as a set of load-bearing elements and a grillage. Support elements may differ in material and installation method. For example, today the practice is to use driven and screw piles. To determine the distance between piles in a pile foundation, it is necessary to take into account the permissible burial depth, material of manufacture and other parameters of load-bearing products - this is how the number of elements and the step between them is calculated. No less significant is the function of the grillage, which provides a bunch of free-standing supports. It can be implemented in different types and structures, but, as a rule, the design of this component entirely depends on the technique of introducing and strengthening the piles.

General principles of calculation

Typically, engineers focus on taking into account the properties of the soil and the expected mass of the future structure - together, this information allows them to lay the optimal pile-screw foundation. The distance between the piles can be calculated based on their number. To determine how many support elements will be required, you should know the load level and the overall load-bearing capacity of the structure. In particular, the pile can withstand about 2 tons, while the weight of the house structure can be tens of tons. Next comes the layout of the placement of piles throughout the entire area. In some cases, the load is uneven, and therefore the location of the piles is not always correct from a geometric point of view.

Step between screw piles

Construction practice in Russian conditions has established the minimum distance when laying a pile-screw foundation: it is 1.7 m on normal soil. In this case, in each pair a gap (at least 0.5 m) of a solid layer of soil should be left, that is, an area where no excavation work has been carried out. This measure will prevent unwanted influence land base on a pile foundation.

The maximum distance between piles for one-story buildings is:

for houses made of logs or timber - 3 m;
for frame and prefabricated panel objects – 3 m;
for buildings made of tongue-and-groove blocks, aerated concrete and cinder block – 2.5 m;
for brick buildings – 2 m.

As you can see, lightweight wooden buildings require a less dense arrangement of piles, however, if a 2-story building is planned, the step can be reduced.

Step between driven piles

The distance between driven support elements requires a universal calculation formula. The main parameter here is the diameter of the pile. It is important to divide structures of this type into two categories: hanging and racks. In the first case, the minimum distance will be the diameter multiplied by three. The maximum involves multiplying the diameter of the pile by six.

The racks are located with a minimum pitch, the value of which is one and a half times greater than its diameter. It is noteworthy that a pile foundation, the distance between the piles of which is reduced to a minimum, does not always improve reliability. The fact is that the cluster (frequent) method of placing supports also creates an undesirable effect in the form of increased sediment. Therefore, it is recommended to always consider the possibility of transmitting loads on piles in a single configuration.

Deviations from the “norm”

Despite the development of uniform rules on the basis of which a method for calculating the distance between piles is drawn up, each case involves a huge number of nuances. In this regard, engineers are beginning to be guided simple rule: indicate the maximum limit of the permissible number of piles and rationally distribute them over the entire area, taking into account the loads.

Depending on the project for which a pile foundation is planned, the distance between piles may be reduced or increased. For example, if the plan provides for an internal load-bearing wall with floor loading on the sides, then it makes sense to reduce the spacing between load-bearing elements by 30%.

Increasing the distance is also not a serious mistake if technical precautions are taken. In such cases, additional installation of foundation beams is usually required. It is difficult to say what could justify increasing the distance, since such a correction is unlikely to make the pile-grillage foundation more reliable. The distance between the piles, which increases due to savings, also does not justify itself. If only for the reason that additional strengthening will cost more than an “extra” but structurally sound row of foundation piles.

Pile location configuration

In addition to the distance between the piles, the way they are organized also matters. The choice of a specific configuration depends on the existing loads. There are several options for arranging supports on the foundation site: individually, in a row, in the form of various geometric shapes and in the form of a continuous field on which a pile foundation is formed. The distance between the piles in each case is based on general rules calculation, but may be adjusted.

The most common are pile strips (row configuration), solid piles and “cluster” dense methods of arranging load-bearing structures. The technique of installing elements in a row is used to support the walls of buildings - this is a common method of constructing foundations for residential buildings. For structures requiring intense loads, the pile “bush” method is recommended. The continuous field structure is designed to support the heaviest buildings and structures. In this case, the piles are distributed evenly and united monolithic grillage with a strong sole.

The installation step of the screw piles determines how reliable the foundation of the house will be. The weight of the building is transferred to the supports, through which the loads are transferred to the ground, so the correct assumption is that the more screw piles are located under the house, the less pressure they will exert on the soil foundation. Thus, we can conclude that the step between the foundation supports directly depends on the total mass of the building, including useful and temporary loads.

Optimal distance between piles

Screw metal supports for a frame or timber house are installed in increments of no more than three meters. But often it is reduced to 1-1.2 meters. This parameter depends on the total magnitude of the loads and soil properties. Calculation, which may not be performed for temporary and non-essential buildings, helps to find out a more accurate distance.

Piles are installed evenly along the length of the wall, always at internal or external corners, at the junction of load-bearing walls and the location of critical components, as well as under the pillars of the frame structure.

When determining the pitch of the screw supports, you should take into account the length of the grillage beams, since both ends must rest on the head of the screwed pipe. This applies to both frame and timber houses. But in the case of constructing a concrete grillage this factor is not taken into account.

If the foundation of the house is intended to be slab foundation, then the location of the screw piles is determined project documentation. This design requires a slightly more complex calculation, but the principle remains the same - the supports are placed under the load-bearing walls or columns of the frame house.

Placement of screw piles in plan

Correctly placed supports will help maintain the integrity of the house. With their help, the load will be evenly distributed under the building area, and therefore unwanted subsidence will be avoided. A house with complex contours in plan requires special attention, especially the corners and junctions of the walls. Installation of screw piles under them is mandatory.

Pile placement patterns depend on design features Houses. There are four types of their arrangement in plan:

single - under vertical posts frame house, at corner points, under load-bearing walls (equidistantly in increments of no more than 3 meters);
strip - under load-bearing walls, but, unlike single screw piles, with a shortened pitch, often reaching up to 0.5 m. The arrangement of supports in the form of a tape allows the foundation to accept and distribute more significant loads;
cluster - under heavy single or group structures, as well as under massive equipment. The step, in this case, does not matter, since the screw piles at the installation site can be placed too close in a chaotic manner. The main condition is that they must be present along the entire perimeter and area of a small-sized slab grillage required for installation, for example, of a heavy load-bearing column of a frame building;
continuous, called a pile field. The supports fill the entire area under the foundation slab in increments of about one meter. This placement of screw piles in plan is practiced when designing heavily loaded objects or when building on soils with too weak bearing capacity.

For private houses and small buildings, as a rule, the first two types of screw pile arrangement are used.

Calculation features

When determining the pitch of screw piles, reasonable considerations should be followed. Too large a distance between the supports will lead to subsidence of the house, and a small distance will lead to overexpenditure of material resources. In this regard, experts recommend performing calculations that take into account:

actual mass of above-ground structures and finishing materials;
approximate weight of furniture and equipment, including communication systems;
snow and wind loads;
bearing capacity of the soil (the exact value is taken by calculation);
technical characteristics of screw piles;
safety factor.

The payload when calculating the installation pitch of piles is determined according to the relevant SNiP or technical specifications. For example, for a one-story residential building it is about 150 kg per square meter area. Indicators of snow and wind loads are taken from reference books, depending on the region of construction of the facility. And the safety factor, as a rule, is 1.1-1.25.

The bearing capacity of piles is directly proportional to the diameter of the metal pipe, the number, shape and size of the blades.

The calculation of the number of screw supports required for the foundation is quite simple. Their number and the linear dimensions of the load-bearing walls in plan influence the installation step of the piles. The total load is divided by the bearing capacity of one metal support. The result is the required number of piles, which are distributed with equal spacing along the perimeter of the building envelope.

Another calculation option comes down to determining the forces acting on one linear meter of grillage. To do this, the total load is divided by the length of all load-bearing walls, after which the result obtained is again divided by the load-bearing capacity of the selected screw piles. The result is the number of supports required to support one meter of strapping under load. Further calculation comes down to finding out at what step the piles should be installed so that the foundation can withstand the calculated forces. This method is intended for massive buildings.

The bearing capacity of metal screw piles is indicated by the manufacturer in technical documentation. Approximate parameters can be found in the table.

The next step after calculation is the schematic placement of screw piles in the foundation plan. As noted earlier, they must be present in corners, under columns and at the junction of load-bearing walls. The remaining piles are distributed evenly between the main supports. This way the exact pitch between the screw piles is determined.

Visual calculations

For example, you can take the calculation of a one-story house made of timber measuring 6*6 meters. The volume of wood is calculated depending on the thickness of the walls and the height of the building, taking into account the roof. Let's assume that it is 20 thousand cubic meters. We multiply the number by the weight of one cube of wood (in our case – 800 kg). As a result, we get a total load of 16 tons. Here we add the weight of roofing and finishing materials (let's say 2 tons).

payload – 36m2*150kg/m2, which is 5.4 tons;
snow load – 36m2*120kg/m2, which is 4.32 tons.

After summing up, we get the figure - 27.72 tons, which we multiply by the safety factor - 1.1. As a result, when calculating the number of screw piles, we use the load indicator - 27.72 * 1.1 = 30.492 t. Taking as a basis piles with a diameter of 89 mm with a design load of 2 tons, we obtain minimum number piles – 30.492/2=16 pieces, which are evenly distributed along the outer perimeter of the house. Additional supports can be installed, for example, for floor joists.

For two-story house the payload is doubled.

The above calculation is not accurate. In each specific case, additional efforts arise, internal load-bearing structures, poles, equipment, etc. appear. Often Decoration Materials significantly increase the weight of the house. All nuances must be taken into account in individual project, establishing the pitch of the foundation supports.

Determined by the total load of the building on the foundation. The distance may vary, it all depends on the foundation design, but cannot exceed three meters - this is a critical distance.

The distance between screw piles is no more than 3000 mm.
Based on the foundation design, the distances between the load-bearing supports also vary. For a heavier structure, it is worth reducing the distance between the piles. A distance of 150 cm between the piles will be sufficient even for a building constructed from aerated concrete installed on a channel mounted on screw piles. But do not forget about the diameter of the piles for each specific structure. The more pile diameter, the more the ability to carry a larger load increases, therefore it is possible to increase the distance between the piles, of course without compromising reliability.
When choosing a foundation, you should consult with specialists and agree on all the details of the project.

for Ø57 mm – 1.5 t for Ø89 mm – no less than 3.5 t for Ø108 mm – no less than 4.5 t for Ø133 mm – not less than 7.0 t for Ø159 mm – not less than 10.0 t Each the screw pile carries the load proportional to the total mass of the building.

Distance between screw piles for foundations with complex contours

When installing screw foundations with a complex contour(with a large number of corners for bay windows), a screw pile should be installed under each corner.

Screw foundation for a house with a bay window

It is especially necessary to install piles at each corner when installing a channel on them. The distance between intermediate piles should not exceed three meters.

You can get advice and order a foundation by calling us 981-84-08

Screw pile pitch

As can be seen from the above, the pitch between the screw piles is selected based on the necessary requirements for each structure. But it is important to consider that three meters between the piles is the extreme distance. When constructing fences based on screw piles, the step between the piles is arbitrary, subject to the following conditions: that the piles do not experience heavy loads during operation. For example, chain-link mesh and similar lightweight materials.

Distance between screw piles

Which distance between screw piles leave? Choosing the necessary step is not difficult, especially for light summer cottage buildings such as frame houses, which have become increasingly popular lately. It is important to consider that it is necessary that all parts of the building structure rest on their weight distribution points. It should not be when part of the structural elements of the building “hangs” in the air and does not rest on the intended point on the screw pile. Consequently, other piles will experience increased critical load, which in turn may possibly lead to negative consequences. It is necessary to arrange a building on a pile foundation so that the weight is distributed evenly; if the design features or defects are such that they do not allow contact transfer of the payload onto the pile, then it is necessary to provide an intermediate connecting element between the elements of the building and the foundation, such materials can be wood or metal . Each pile takes on the design load of the entire building, and the snow load in winter is also taken into account. When tying a pile field with a channel or other heavy material (concrete strip, slab), it is necessary to take into account this load on the screw piles.
As described above, the distance between screw piles should not exceed three meters, especially for frame houses. where a distance of more than 3 m causes the timber or board to sag.

Distance between screw piles for a frame house

Distance between screw piles for frame houses may vary based on the features of architectural solutions during design. Piles must be installed in the places of the castle connections of the first crown of the building, at the corners of the bay windows, in the places where the logs should lie. it is necessary to remember that the more piles there are in the “field” of the foundation, the greater the load the foundation can support and vice versa. Also, soil and terrain features can influence the number and distance when placing piles. Areas with a strong slope, swampy, heavily flooded in lowlands require the use of a larger number of piles when constructing screw foundations, this is especially true for swampy soils with a large layer of peat and mobile soils, using a power frame in the form of channel piping and other binding steel materials.

One of the most common foundation options today is a pile foundation. Foundations on piles have been known for a very long time. For the first time, piles began to be used in the construction of bridges, where reliability and quality were certainly required.

In this article we will look at what distance should be between screw piles in a frame frame.

In ancient Rus', churches were often built on wooden piles. The foundation on piles is used for heaving and embankment areas, with an extremely unreliable composition of the upper soil, which contains clay, is highly saturated with water, humus, peat, etc. It can be used on a variety of soils without worrying about uneven shrinkage occurring.

What steps should be taken between screw piles?

Let's say right away that everything is individual and calculated separately for each house project, but on average the distance between screw piles should be about 2 meters, but not more than 3 meters. It all depends on the frame of the house that you use, usually one-story and two-story houses do not require a very close distance between the piles, but many companies that install screw piles try to sell us as much as possible and install piles almost every meter, such a foundation for us I don’t need it with you, why pay twice as much?

Construction of a pile foundation has two main distinctive features which can be considered as advantages. The first is the possibility of deepening up to 30 m in order to achieve dense layers soil. The second is the construction of a foundation for the construction of a house in places where no other types of foundations can be laid due to technical and economic reasons, for example, over water.

Below we give examples and advantages of using a pile foundation:

This type of foundation does not require additional earthworks, for example, excavating pits or trenches.
It is easy to attach an additional object to a house built on stilts
Compared to a strip foundation, work on a foundation on piles takes only a few days.
The construction of a foundation on piles does not depend on weather conditions and time of year.

Types and order of placement of piles

Currently, many types of piles have been developed, which differ from each other in several parameters:

By appearance- from round to polygonal cross-section, with rectangular, pyramidal and conical rod shapes;
By design - hollow, solid, tubular, solid, composite;
By material - wood, metal, reinforced concrete, concrete, combined;
By type of nozzles - conical, sliding, with extension, screw cutter and without them;
According to the method of reinforcement - longitudinal, transverse, stressed, unstressed and without reinforcement;
In terms of functionality - standing and hanging.

Standing piles- structures that are installed deep into dense layers of soil. In this case, the load is absorbed directly by the soil on which the pile rests.
Hanging piles- structures in which the load from the weight of the house is transmitted through the side surfaces of the pile into the soil. This type is most often implemented in pyramidal and conical structures for penetration into dense soil, under which there may be an aquifer.

The location of the piles depends on the characteristics of the soil, the terrain and can be single, row, cluster or combined.

The single option is usually used to strengthen slab foundation elements in the center, under individual walls or corners.

Ordinary option- the most common when constructing pile foundations, it can be used along the line of one wall, along the perimeter of the building and under partitions.

Cluster arrangement piles is the strengthening of a single option at some point in the development, where several pillars located close to each other serve as a single support.

Combined option pile arrangement is used on complex terrain and moving soils, when at different points of the building site it is necessary to lay one or more pillars in order to strengthen a certain section of the pile foundation.

Methods for laying a foundation

There are several main ways to construct a pile foundation in individual construction.

What is better: reinforced concrete piles or screw piles?

Fill reinforced concrete piles involves drilling a well of calculated depth, after which it is introduced reinforced frame and served concrete mixture. Driving of finished piles with strong and pointed ends is carried out using special machines equipped with a hydraulic or pneumatic hammer.

Pressing piles requires special equipment. This method is used in populated areas where the operation of hammering and vibrating equipment disturbs the peace of citizens, or in areas where dynamic effects on soils can cause landslides, soil erosion or landslides from mountain slopes.

The installation of piles by vibration is used on wet, loose soils. During operation, the pile sinks into the soil under its own weight with the help of vibration forces. At the same time, the soil around and under the pile is compacted.

Driving concrete piles is only necessary for high-rise residential buildings; frame houses do not require a solid foundation and small screw piles are perfect for them, which are easily installed in one day, this is their invaluable advantage!

Screwing in piles is similar in technology and work conditions to indentation. The difference is that everything can be done manually, or it can be done on the equipment of the immersed end of the pile with a screw attachment. The technique that is used to screw piles into the ground can be used to drill wells for pouring reinforced concrete piles.

Before installing this type of foundation, a geological survey or test driving of piles should be carried out to determine the quality of the soil, as well as possible hidden indicators. In order to minimize the impact of soil mobility on the foundation, and also to ensure that the foundation can support the weight of the supporting structure, piles should be driven in at certain intervals. For each individual project, individual calculations of the gaps between screw piles should be made. After calculating the gaps between the screw piles, the foundation is selected. The calculation is made using standard formulas at the stage of developing a frame house project.

Let's consider several circumstances that should be taken into account when calculating the foundation of a frame house:

Soil quality, degree of soil moisture due to rainwater, presence of groundwater, humidity level;
The total weight of all partitions and walls;
Determine what the foundation will be based on the shape and structure of the foundation;
Determine the level of beam distribution along the grillage frame. The distribution of timber along the grillage frame can be in-line or staggered.
As well as the load on the foundation, type and characteristics (total weight of the house);

To calculate the mass of a house, it is worth taking into account all the main structures and multiplying by the density of the corresponding material. Also, to calculate the mass of the house, you should add the mass of the inhabitants, all furniture, appliances, stairs, windows, etc. We multiply the resulting result by the safety factor. Data on the density of building materials can be found in any reference book. Of course, it is quite difficult to calculate and calculate everything accurately; in this case, statistics can help. For frame houses, the mass of load-bearing walls should be multiplied by three.

The grillage is the most optimal and universal solution for organizing strong, reliable and high-quality foundations for a house, primarily due to the fact that this design embodies the best performance of columnar, pile and strip foundations. Grillages can be installed on reliefs of any complexity with a wide variety of soil characteristics without restrictions on the type and weight of buildings. The only exceptions are solid rocks, where the development of pits or wells is impossible or economically infeasible.

Low grillage arranged on dry, dense and loose soils with minimal influence of flood, storm and melt water.

Raised grillage laid on soils with a low degree of heaving, where significant moistening of the surface layer of soil is possible under the influence of storm, flood and melt water.

High grillage organized on any soil with a medium and high degree of heaving. In this case, the lower edge of the grillage tape is raised at least 10-15 cm above ground level to avoid the influence of stress forces from surface swelling of the soil during frosts.

The choice of grillage type depends on the condition of the soil, local climatic conditions and the weight of the building, taking into account possible snow load. Determining the number of columns, the distance between piles and the width of the monolithic tape are important design indicators. Therefore, it is better to entrust this part of the calculations to specialists. Marking, preparing holes for pillars or laying piles is carried out using the same technologies as for piles and columnar foundations, and filling the tape is similar to the construction of a strip foundation.

Features of a pile foundation

When building small frame houses, a pile foundation is recommended. However, when constructing large, tall buildings the use of this type of foundation is undesirable, since the structure will be exposed to strong winds, as well as many other external factors that can lead to the destruction of the building.

A huge advantage of screw piles is that the construction of a house can be done on a slope

Instructions for installing a pile foundation

The first thing to do is select and mark the area for building a house on stilts. In order to exclude possible problems in the future, you should obtain a plan for underground communications and power cable networks.

Be careful when marking the future

foundation

The marking does not accept errors; it requires attention and maximum accuracy.

Installation of piles. There are several simple ways. For example, we screw piles into the ground until they stop by hand, or we drive them mechanically. In the intended location for installing the piles we make a small recess, the so-called guide. Next, the support is erected. The support should be installed strictly vertically.

The support lever becomes a crowbar installed in the support hole on which the pipe is installed. You should initially install the supports strictly vertically, since it will not be possible to correct them in the future. Therefore, when screwing in, you should carefully monitor the position of the support and, if necessary, adjust vertically. In some cases, you need to manually prepare a recess of up to 50 cm, or maybe more - this problem can arise in the presence of stones or hard soils.

The depth of immersion of piles is calculated individually according to the project and should not exceed the level of hard soil rocks.

Rules for working with screw piles

Upon completion of the installation of the supports, they are leveled in height and, if necessary, trimmed with a grinder; this should be done in order to eliminate the horizontal subsidence of the slabs and beams of the base of the house. The height of the foundation screw piles above ground level should not exceed 60cm. Next, the structure is filled with concrete in order to obtain the strength and reliability of the foundation of the future house. It is also important to remove excess air from the concrete surface, as this can lead to future deformation of the concrete slab. The next step is to weld the ends and tie them with timber. You can also use metal channels, replacing timber with them. When using a channel, the heads can be eliminated, which will significantly reduce the cost of the foundation and the future house.

When constructing a pile foundation, it is strictly prohibited:

Lengthen or correct twisted piles;
Use damaged piles;
Immerse the piles to a depth of less than one and a half meters from the top ground level;
Allowing a vertical slope of more than 2 degrees;
When screwing in, adjust the piles to the horizontal level.

Before installing a pile foundation, it is very important to carefully familiarize yourself with the technologies and installation rules. In the future, this will definitely bring great benefits, and you will also get a high-quality and durable foundation for your future home.

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Optimal distance between piles

Piles are installed evenly along the length of the wall, always at internal or external corners, at the junction of load-bearing walls and the location of critical components, as well as under the pillars of the frame structure.

If a slab foundation is planned for the foundation of the house, then the location of the screw piles is determined by the design documentation. This design requires a slightly more complex calculation, but the principle remains the same - the supports are placed under the load-bearing walls or columns of the frame house.

Placement of screw piles in plan

Pile placement patterns depend on the design features of the house. There are four types of their arrangement in plan:

single - under the vertical posts of a frame house, at corner points, under load-bearing walls (equidistantly in increments of no more than 3 meters);
strip - under load-bearing walls, but, unlike single screw piles, with a shortened pitch, often reaching up to 0.5 m. The arrangement of supports in the form of a tape allows the foundation to accept and distribute more significant loads;
cluster - under heavy single or group structures, as well as under massive equipment. The step, in this case, does not matter, since the screw piles at the installation site can be placed too close in a chaotic manner. The main condition is that they must be present along the entire perimeter and area of a small-sized slab grillage required for installation, for example, of a heavy load-bearing column of a frame building;
continuous, called a pile field. The supports fill the entire area under the foundation slab in increments of about one meter. This placement of screw piles in plan is practiced when designing heavily loaded objects or when building on soils with too weak bearing capacity.

For private houses and small buildings, as a rule, the first two types of screw pile arrangement are used.

Calculation features

actual mass of above-ground structures and finishing materials;
approximate weight of furniture and equipment, including communication systems;
snow and wind loads;
bearing capacity of the soil (the exact value is taken by calculation);
technical characteristics of screw piles;
safety factor.

The payload when calculating the pitch of pile installation is determined according to the relevant SNiP or technical specifications. For example, for a one-story residential building it is about 150 kg per square meter of area. Indicators of snow and wind loads are taken from reference books, depending on the region of construction of the facility. And the safety factor, as a rule, is 1.1-1.25.

The bearing capacity of piles is directly proportional to the diameter of the metal pipe, the number, shape and size of the blades.

The bearing capacity of metal screw piles is indicated by the manufacturer in the technical documentation. Approximate parameters can be found in the table.

Visual calculations

payload – 36m2*150kg/m2, which is 5.4 tons;
snow load – 36m2*120kg/m2, which is 4.32 tons.

After summing up, we get the figure - 27.72 tons, which we multiply by the safety factor - 1.1. As a result, when calculating the number of screw piles, we use the load indicator - 27.72 * 1.1 = 30.492 t. Taking as a basis piles with a diameter of 89 mm with a design load of 2 tons, we obtain the minimum number of piles - 30.492/2 = 16 pieces, which are evenly distributed along the outer perimeter of the house. Additional supports can be installed, for example, for floor joists.

For a two-story house, the payload doubles.

The above calculation is not accurate. In each specific case, additional efforts arise, internal load-bearing structures, poles, equipment, etc. appear. Often finishing materials significantly increase the weight of the house. All nuances must be taken into account in an individual project that establishes the pitch of foundation supports.

The distance between screw piles is one of the technical parameters necessary for the construction of a house or utility structure. It is determined at the design stage and depends on the magnitude of the load on each element of the foundation support. Errors in determining the distance between metal screw piles affect the reliability and durability of the house, so all calculations should be performed especially carefully. The conditions and methodology for their implementation are regulated by GOST 27751-2014 and other regulatory documents.

Initial data

Before starting the calculations, you must choose the option of locating the piles under the grillage of the house or outbuilding. He can be:

Chess. In this case, the foundation piles are installed at framing angles, and the distance is measured diagonally between adjacent elements.
Row. With this distribution, the supports are installed in one row, placing them parallel to the side edges of the grillage.

What should be the distance between screw piles? During the calculation process, the following should be taken into account:

the shape of the base of the house;
soil characteristics;
the magnitude of the load acting on the foundation and its features.

In addition, it is necessary to take into account the strength of the supports and grillage. The most difficult thing when planning the construction of private houses is studying the soil parameters. Moreover, it is necessary to find out not its type and other parameters on the surface, but the bearing capacity at the depth of the foundation supports after screwing in. To do this, a hole up to 2 m deep is laid through the thickness of the soil.

To simplify the calculations, after determining the load and number of piles, an approximately 30% safety margin can be provided, increasing the data obtained by this amount. This technique will compensate for too much load on the foundation due to abnormal snowfalls, soil heterogeneity and other factors.

Analysis of the soil composition can be carried out during test screwing, which is necessary to assess the distance to dense layers and select the required length of piles. Soil density is determined from a reference book.

Calculation method

Calculation of the distance between supports for a pile foundation is carried out in several stages. To do this you will need:

estimate the weight of the house;
determine the required number of piles, taking into account their type, size, bearing capacity and soil parameters.

Upon completion of the calculations, plan the location of the supports under the foundation of the house in such a way that they are located not only at the corners of the external walls, but also under structures made of heavy materials. The load acting on the supports must be the same, as well as the distance between them.

Estimation of building mass

The weight of a building is determined by summing up the mass of all its structural elements, and adding the load from snow, interior furnishings and other components. The resulting value is multiplied by the safety factor.

However, this calculation option is quite complicated, so the mass of the house is determined using statistical data. According to them, usually the weight of external walls almost coincides in size with the weight of the remaining elements and contents, taking into account the snow load.

Construction specifics frame structures and houses made of sip panels is to use materials with good load-bearing capacity and low weight. Therefore, the calculation of the total weight for such buildings is calculated by tripling the mass of the external walls.

The volume of supporting structures is obtained by multiplying their length along the perimeter of the house by thickness and height. For further calculations, it is necessary to know the density of the walls, which depends on the type of materials used and is indicated in the reference literature.

Determination of the number of supports

To calculate the number of piles, the resulting mass of the house, taking into account the additional safety factor, must be divided by the bearing capacity of one structural element. Calculation of the load that the foundation support must withstand is determined by the following parameters:

length and diameter of the pile blades;
material strength;
structure and density of the soil at the level of the blades after twisting.

The characteristics of the soil depend on its type and are determined from the reference book.

The lower the bearing capacity of the soil at the site where the house is built, the shorter the distance between the foundation supports.

Distance between piles

Unlike other types of piles, the minimum distance between screw supports is not regulated, but largely depends on the strength of the grillage. According to practical data based on calculations obtained during the construction of houses in Russian conditions, it is 1.7 m on sites with ordinary soil.

The maximum distance depends on the material of the walls and for one-story buildings should be:

for frame and prefabricated panel structures – 3 m;
for buildings made of timber or logs - at least 3 m;
for brick buildings – 2 m;
for houses made of cinder blocks and aerated concrete - 2.5 m.

For taller structures, the step between the supports of the pile foundation is smaller.

If necessary, the maximum distance from one pile to another can be increased, but in this case a grillage will have to be erected taking into account the additional load, for which additional calculations are required.