Installation of a pile-screw foundation requires scrupulous calculations. For any columnar foundation, determining the location of the supports and calculating their load-bearing capacity is fundamentally different from the calculation of monolithic foundations. In this case, the weight of the structure and other loads are not distributed evenly throughout the monolith, but fall on each individual pile.

1. Loads on the foundation

The main load on the foundation is borne by the weight of the future structure. If a house is being built, then to determine the total load you need to know the weight

• Foundation strapping
• Bottom floor
• External and internal walls
• Top floor and ceiling
• Roof truss system
• Roofing material
• Engineering communications
• Window and door blocks
• Finishing materials
• Porches and verandas, if they are on the same foundation as the house

In addition, the screw piles themselves exert loads on the soil, as the final support of the structure - the larger the diameter of the pipes used, the greater the weight.

All of the listed parameters are initial and unchanged after the construction and commissioning of the house. The operation of the house introduces new loads on the foundation, in particular

• Weight of people in the house
• Equipment weight
• Weight of furniture and household appliances
• Weight of snow on the roof

Obviously, the operational loads will be variable, but they need to be taken into account in the calculation to the maximum.

All indicated loads are vertical. But besides them, when operating a house, lateral influences are added:

• The force of the wind pressing on the walls and roof slope
• Seismic loads
• Forces of soil heaving in winter
• Structural loads associated with changes in the linear dimensions of building elements (wood shrinkage, moisture, etc.)

All loads differ not only in their strength, but also in the place of application, as well as in the time of exposure. The following types of loads are distinguished:

1. Equally distributed - the weight of the building itself or snow on the roof
2. Concentrated, such as the weight of equipment or furniture in a limited area of ​​the house
3. Static – constant over time
4. Dynamic – for example, shock from wind gusts or vibration from heavy equipment

In some cases, the loads may coincide, increasing the overall impact on the support, and this must also be taken into account in the calculation of the foundation.

2. Main reference points

When calculating, you need to have an idea of ​​how certain loads act - from here you can determine the position of the support points of the columnar foundation. To do this, consider the structure of the building and how the loads are redistributed across it.

Thus, the weight of the roof and the snow on it is transferred to the rafter system. That, in turn, is installed on the side walls and, in some cases, on the top floor. The ceiling also rests on the side and internal load-bearing walls. In some cases, the roof may protrude beyond the perimeter of the base of the house and rest on separate supports - pillars or columns - in this case, some of the loads on the walls are reduced, but additional support points must be provided in the foundation design.

Thus, it is obvious that vertical loads from the roof and roof are mainly directed towards the walls of the building.

This means that the foundation support points should be located primarily under the walls. As a rule, supports are placed along the perimeter of the entire building and along the lines of the load-bearing walls. The walls themselves, with their weight and loads transferred from the upper part of the building, put pressure on the foundation frame.

The lower overlap puts pressure primarily on the side supports, i.e. on the beams of the lower frame of the foundation - along the perimeter and, in a more complex case, along the transverse beams.

As mentioned above, the building may have additional elements that increase the overall weight of the house. An example is massive boiler equipment. Despite the fact that the weight of any objects in the room is transferred more or less evenly to the lower floor, in such particularly loaded areas additional local loads are created on the floor beams themselves, more precisely on the areas located directly under the equipment location.

Obviously, they require the creation of separate reference points.

3. Taking into account soil characteristics

The characteristics of the soil from the point of view of installing the foundation determine, first of all, its load-bearing capacity, that is, resistance to loads from structures installed on it without subsidence. It is measured in tn/m2 or kgf/cm2. The most significant for the bearing capacity of the soil are

• Soil type
• Compaction degree
• Humidity

To study soil parameters, in general, it is necessary to conduct geological surveys. However, their cost is quite high, and in practice, builders use generalized parameters gained by experience for certain soils, and also use simplified methods for determining soil properties.

Firstly, there are certain known characteristics for the main types of soil on which construction is planned - sandy or clay.

Secondly, a trial screwing of the piles is carried out.

To independently determine the type of soil, you can use the well-known method -

Roll a ball out of the ground and rub it with your palms. In this case you can see that:

1. The sand ball practically does not roll, and when rubbed, individual grains of sand can be felt
2. A ball of sandy soil (up to 90% of the composition) is formed, but collapses under the smallest loads
3. A ball made of loam (up to 30% clay) holds its shape, but when exposed to loads it cracks at the edges
4. The clay ball forms perfectly and does not crack when pressed.

The density of various types of soils and their bearing capacity are determined by practice and are given in tables. Here are some parameters for the most commonly used soils:

• Medium sand – 4-5 t/m2
• Fine grained sand – 3-4 t/m2
• Fine-grained wet sand – 2-3 t/m2
• Sandy loam – 2.5-3 t/m2
• Moistened sandy loam – 2-2.5 t/m2
• Coarse sand – 5-6 t/m2
• Loam – 2-3 t/m2
• Clay – 2.5-6 t/m2
• Wet clay – 1-4 t/m2

Moisture saturation can also be determined in a simple, proven way. Dig a small hole (up to half a meter deep): if after some time water accumulates in it, then the soil can be considered wet. Otherwise, dry.

Summarizing what has been said, we can say with confidence that you can safely use the data given above to independently calculate the foundation. Typically, the type of soil in a given area is known.

Test screwing will help to identify how the general type of soil characteristic of nearby areas may locally differ from the average.

4. Determination of pile parameters

In order to determine the parameters of piles installed as a foundation, it is necessary to know their load-bearing capacity. Calculations show that the permissible load on the pile depends on the pipe diameter, wall thickness, pile length and blade width.

Theoretically, the load-bearing capacity of a pile is calculated using the formula

S – support area, i.e. blades

Ro – strength characteristics of soil

Since the calculation of soil parameters was taken not from geological studies, but from tables, it is necessary to apply a reduction factor. In most cases, it is taken equal to about 1.4-1.7, that is, the foundation is calculated with a safety margin of up to 70%.

The average characteristics of various piles have been established experimentally. Thus, piles with a diameter of 108 mm can withstand loads of up to 5-7 tons. With a diameter of 89 mm, the maximum load-bearing load is about 3-5 tons. The thinnest piles with a diameter of 73 mm can support up to 3 tons of weight.

The choice of screw pile length depends mainly on the type of soil on which the blade will rest. So, in areas with stable soil, a pile length of 2.5 meters is sufficient. The final choice should take into account the margin for height differences on the construction site.

5. Calculation of the number of piles

From the previous paragraph we see that the number of piles for a particular foundation can be determined by dividing the total weight of the house by the load-bearing capacity of one pile.

Let us give an approximate calculation of the number of piles for an ordinary house.

So, its weight will be the sum of the weight of the entire building, multiplied by the reliability coefficient for a particular type of structure. It is equal at constant load:

1. For wooden structures – 1.05
2. Metal structures – 1.2
3. Screeds, insulation – 1.3
4. For snow load – 1.4

6. Distribution of piles over the foundation area

There are basic rules for the distribution of piles:

1. Piles must be installed at the corners of the building. These are the most stressful points, since the loads from at least two walls converge here.
2. If necessary, one or more piles are installed under each wall, depending on the length of the walls, including internal load-bearing ones
3. In areas with high loads, piles are also installed in the corners.

Let us give a calculation of the number of piles for a house with an attic, which puts a load on the foundation of up to 50 tons, taking into account the given coefficients.

Quantity required to build a foundation for such a house:

• Piles with a diameter of 108 mm - 50/6 = 8.3 piles. In reality, 9 piles are required.
• Piles with a diameter of 89 mm - 50/4 = 12.5 piles. 13 piles are taken with a reserve.

With a rectangular section of 6x4.5 m and one load-bearing wall of 6x3 m, the piles are installed: 4 in the corners, the rest along the walls.

Consider the use of an 89 mm pile. 4 piles are placed at the corners of the building. Two piles are installed at the ends of the internal load-bearing wall. Thus, 13-6=7 piles remain. It is advisable to install one under the midpoint of the load-bearing wall, and distribute the rest around the perimeter. If you add two more piles, then there will be 2 piles on each of the side walls (except the corner ones). Then their installation step will be 1.5 meters, which is quite consistent with a good safety margin.

7. Conclusion

Calculation of the foundation is of great importance in laying the foundation for construction, especially on soft soils and natural slopes of the site for building a house. You can do it yourself, but when building a large house it is better to turn to specialists.

The K-DOM company specializes in the construction of foundations on screw piles and has experience in calculating foundations of any complexity. We are ready to provide consulting services, carry out control screwing and give competent recommendations on the use of a particular type of foundation, as well as install a turnkey pile-screw foundation.

Screw pile foundation calculator - online calculation - an easy way to navigate prices for products/construction work.

Turnkey foundation calculator

The most important advantage of an online calculator is that it allows you to perform all the calculations yourself without the help of a specialist. The scheme itself is also quite simple.

On most of the pages of our website there is a “Foundation Calculator” button in the upper right corner. By clicking on it, you go to a separate page on which the required fields are located. You will be required to indicate the type of building (house, bathhouse, fence, pier), wall material (for a house it is wood, frame or brick, for a fence - corrugated sheets, chain-link mesh), number of floors, size of the building. This data is necessary to determine the loads from the structure.

For convenience, all fields are equipped with drop-down tabs, which indicate the most common options. This significantly reduces filling time.

The foundation calculator from the GlavFundament company also includes two additional fields - soil conditions and soil corrosion activity. When filling them out, you may probably have questions, since almost all organizations on the market do not request this information to calculate the price of piles/construction and installation work. Why did we make them mandatory?

The parameters of piles, their number, and placement in the foundation can be assigned only on the basis of information about the loads from the structure and the soil. If both of these factors are not taken into account, there will be a risk of subsidence (when the thickness of the layer of dense soil under the pile is less than 1 meter or seasonal wetting of some types of soil, reducing their bearing capacity) or buckling (under the action of tangential forces of frost heaving) of the foundation. You also cannot be sure that the service life of the structure will be as required by GOST 27751-2014 “Interstate standard. Reliability of building structures and foundations. Basic provisions".

Effective operation of two-bladed screw piles is possible only with a calculated distance between the blades based on soil data. The same applies to the pitch of the blades and their angle of inclination (more information in the article “Features of calculating two-bladed screw piles”).

The thickness of the metal and the grade of steel are also variables that depend on the degree of corrosive activity of the soil. If the environment is highly aggressive, and the pile is made of St3 steel with a wall thickness of 4 mm or less, you should not expect that it will last more than 15-20 years.

The online calculator developed by our company is suitable only for low-rise construction projects. The foundations of industrial and large civil facilities (pipelines, stands, masts, towers, power lines) are calculated using computer-aided design (CAD) systems after conducting full-fledged geotechnical surveys. To confirm the results obtained, control tests of soils under the action of pressing, pulling and horizontal loads are organized. This is due to increased requirements for the level of security of these facilities.

If you need to calculate an industrial or large civil building, follow the link and fill out an application to the design department of our company, indicating the necessary data. If additional information is required, we will call you back.

Quantity calculation, selection of structures and arrangement of piles

When determining the number and combinations of piles in the Foundation Calculator program, the requirements of regulatory documents in force in the Russian Federation are taken into account, as well as design standards developed by our specialists based on the results of research and testing, both our own and those carried out by foreign specialists.

The foundation structure of almost any structure (house, bathhouse) is affected by several types of loads at once (under critical components of the structure, under load-bearing and non-load-bearing walls, under floor joists). Each type of load requires the use of a pile design with a certain load-bearing capacity. Therefore, the proposed solution will include not one, but several types at once.

But there are points that are difficult to take into account when calculating online. These are, for example, the characteristics of the grillage sagging (calculated value). There is an opinion that in order to avoid sagging of the grillage, it is enough to adhere to the generalized values ​​of permissible loads. It is not correct. The span between piles is determined for each object, taking into account the loads on the strapping material from each wall.

In this regard, the calculation performed in the foundation calculator can only be considered preliminary. It helps you get a general idea of ​​the price, but it is not a solution that will guarantee the safety of the building.

Screw foundation calculator

When creating a calculator for calculating a screw foundation, we set ourselves the task of developing a program that would be convenient and at the same time useful.

Firstly, we can compare prices. Plus, you don’t need to open many tabs to do this; all the necessary information is on our website. The service calculates the price in three categories at once (“Economy”, “Standard”, “Premium”). The final figure will also include the cost of construction and installation work (to do this, just check the “Including work” box).

For example, fences and piers are usually classified as lightweight structures, which is why single-bladed piles are often recommended for them. This seems correct, because small loads from objects do not require the construction of a structure with a large load-bearing capacity. But this approach does not take into account the impact of significant pulling and horizontal loads on the piles.

Fences made of wood or corrugated sheets are characterized by high windage. Piers and moorings are exposed to currents and ice melting. The resulting force will constantly try to pull the pile out of the ground. And this type of impact is least preferable for structures with one blade.

To avoid possible consequences, you will be forced to concrete the base of the column or tie it with a channel or corrugated pipe. The introduction of an additional blade will solve this problem even without additional reinforcement of the structure.

House foundation calculator. Price calculation

The foundation calculator is a convenient tool for pre-planning the foundation structure for a house, bathhouse or any other low-rise construction project. It is also indispensable when you need an approximate price estimate to understand possible costs.

But we do not recommend relying solely on these programs. Still, a service is only a set of algorithms that cannot fully take into account the characteristics of an object and site, and cannot replace the experience of a design engineer. And if you consider that the design department of the Glavfundament company performs calculations free of charge and within 24 hours, then the choice will become obvious.

In contact with

Classmates

Adhering to a professional approach to construction work, the necessary calculations should be made during the design.

They will allow reduce time and effort to complete the entire scope of tasks and significantly save materials.

A pile foundation made of metal supports with blades at the end is the most economical and popular type of foundation for difficult terrain areas.

Technological technologies allow its construction to be completed in 3 days, and the foundation will serve for at least 100 years.

For this to happen, you need to evenly distribute the load-bearing load of the structure being built, take into account the characteristics of the soil, the level of freezing and the occurrence of groundwater.

As a result of the calculations, you can get:

• height of screw piles;
• the depth of their placement;
• optimal diameter of supports;
• total amount;
• total cost of expenses.

Conclusion: calculation of the foundation saves time and money, guarantees the durability of the structure.

Sequence of calculations

A common method for calculating screw piles according to SNiP 2.02.03-85 relies on geodetic data for a specific development site, which includes information about:

• terrain of the site;
• soil composition and density;
• groundwater level;
• soil freezing level;
• the volume of seasonal precipitation characteristic of a given climate zone.

Advice: If it is impossible to carry out geodetic research, the calculations are guided by the minimum design load.

To perform the calculation, we first calculate the number of screw piles ( TO). To do this you need to know:

• total load on the foundation (R), which is calculated according to tables of the specific gravity of materials (in kg);
• reliability factor (k) as a correction to the load value (it must be multiplied by R);
• soil bearing capacity, determined from the table of average loads on screw piles;
• pile heel area depending on the diameter (according to the table);
• maximum permissible load (S) per pile (according to the table).

The obtained data is substituted into the formula according to which the foundation on screw piles is calculated: K = P*k/S

Reliability factor(k) consistent with the number of piles:

• k = 1.4 - for 11-22 pcs;
• k = 1.65 - for 6-10 pcs;
• k = 1.75 - for 1-5 pcs.

Each pile carries a load proportional to the total load of the structure.

Using the above formula, coefficient and screw piles for the foundation, load calculation and subsequent construction are performed quite simply.

For the final calculation, it is necessary to distribute the load under load-bearing walls and areas of high pressure on the foundation, considering:

• type of piles (hanging or rack);
• roll force indicator.

Reference! For accurate calculations and professional design of pile foundations, there are computer programs StatPile and GeoPile available on the Internet. They are accompanied by a manual and 10 specific calculation examples.

Options

The calculation of a screw foundation and the load on it consists of determining the following parameters:

1. The mass of the structure itself(in kg) - constant value:

• walls and partitions;
• floors;
• roof.

2. Extra weight- temporary loads:

• the weight of snow that fell on the roof;
• operational weight of the contents of the house: furniture, equipment, finishing materials, including people (on average - 350 kg/m²).

3. Correct calculation of the load on a pile-screw foundation is impossible if you do not take into account dynamic loads(short-term):

• created by gusts of wind;
• structures resulting from settlement;
• arising from temperature changes.

How a screw foundation is calculated is further described in the video below:

Types of screw piles

By type of piles there are:

• wide blade with cast tip(at the cone ᴓ6…14mm) - for low-rise buildings on simple soils;
• multi-bladed with several blades at different levels- for increased loads in difficult soils;
• variable perimeter piles- for specific tasks;
• narrow blade with cast toothed tip- for rocky soils and permafrost.

Reference: Barrels made from seamed pipes with welded blades are less reliable.

Specifications

The technical characteristics of screw piles include:

• barrel length and material;
• trunk diameter;
• type of blades, method of connecting them to the body of the pile.

Diameter

Diameter of pile shafts selected from the standard range, correlating with the design load:

• ᴓ89mm (blade ᴓ250mm) - for a load-bearing load of no higher than 5 tons (frame-panel buildings of 1 floor);
• ᴓ108mm (blade ᴓ300mm) - for a load-bearing load of up to 7 tons (houses made of timber, foam blocks, two-story frame houses);
• ᴓ133mm (blade ᴓ350mm) - for bearing loads of up to 10 tons (buildings made of brick, aerated concrete, channel).

Length

Pile length selected based on soil density indicators (according to the table) and elevation differences on the building site:

• when loams occur up to 1 m from the surface, the length of the pile is 2.5 m;
• loose soil or quicksand - the length of the pile is determined by the length of the drill that has reached the dense layers;
• when there are differences in relief heights, the length of the piles may differ by 0.5 m for different areas.

Number of supports and distance between them

Optimal distance between supports:

• 2-2.5 m - for wooden frames and block buildings;
• 3 m - for houses made of timber and logs.

Important: to ensure reliability, the base of the building should not rise above the ground higher than 60 cm, and the length of the pile should have a margin of 20-30 cm.

Having made calculations using the formula K = P*k/S, necessary distribute the position of the piles in the perimeter to balance the load they accept:

• under each corner of the structure;
• at the intersection of load-bearing walls and internal partitions;
• at the entrance group;
• inside the perimeter, guided by a step of 2 meters;
• under the stove or fireplace (at least two piles);
• under load-bearing walls on the side of the balcony or mezzanine.

For your information! Objective conditions may require an increase in the number of piles compared to the calculated one - such a margin of safety will allow you not to be afraid of changes that arise during operation.

Grillage

The grillage serves to evenly distribute the load on the base structure. Regardless of the type of grillage (prefabricated or monolithic, high or low), for its reliability it is necessary to calculate the following parameters:

• foundation pushing force;
• pushing force at each corner;
• bending force.

They are subject to vertical loads from below and deforming loads from the sides (in the ground and on the surface). All this is quite difficult to calculate for a non-professional.

As for , this intellectual work can be done using computer programs StatPile and GeoPile. There is an easier option - to use the individual construction standard, which establishes:

• connection of supports with grillage - rigid or loose;
• the depth of insertion of the pile head into the grillage is at least 10 cm;
• the position of the grillage is not lower than 20 cm above the ground;
• the width is equal to the thickness of the walls (at least 40 cm);
• grillage height - 30 cm or more;
• reinforcement (longitudinal and transverse) with rod ᴓ10-12 mm.

Important! In unstable soils, the strength of the pile foundation will be strengthened by metal at the level of the base (with an angle or channel).

Example of calculation of a pile-screw foundation

The following example describes in detail how to calculate a foundation on screw piles for building a frame house.

Initial data - 6x6 pile-screw foundation:

• a typical frame house with a porch under a slate roof;
• dimensions - 6 by 6 foundation on screw piles with a height (h) of 3 m;
• two mutually intersecting internal partitions dividing the space into 3 rooms;
• roof with a slope of 60⁰;
• frame material - timber 150x150;
• wall material - sandwich panels;
• grillage material - timber 200x200.

1. Determining the area each wall:

• load-bearing - 18 m²*4 = 74 m²;
• partitions - 9*2 + 12 = 30 m².

2. Determining the load of the walls using the table:

• for load-bearing walls - 50 kg*74 = 3700 kg;
• for partitions - 30kg*30 = 900 kg;
• total 3700 + 900 = 4600 kg.

3. Adding weight for 36 m² area:

• basement floor - 150 kg*36 (house area) = 5400 kg;
• attic floor - 100 kg*36 = 3600 kg;
• roofs 50 kg*36 = 1800 kg;
• in the end - 4600+5400+3600+1800 = 15400 kg.

4. Adding additional weight and dynamic loads(snow crust weight = 0):

• 350*36+15400 = 28000 kg.

5. Choosing a reliability coefficient 1,4.

6. Take from the table maximum permissible heel load(ᴓ300) of one pile element: it is equal (according to the table) 2600 kg, with a calculated soil resistance of 3 kg/cm² (soil of medium density, with deep groundwater and freezing of no more than 1 m).

7. Substitute the values ​​into the formula K = P*k/S- 28000*1.4*2600 = 15 (pcs).
In this case, we will install 12 piles at corners and intersections, and use 3 to strengthen areas with increased load.

Installation procedure

It happens that the soil under the foundation is not complicated by quicksand or rocks.

In such cases quite accessible to non-professionals:

1. The most time-consuming and responsible part is making the calculations.
2. Prepare the necessary material and tools.
3. According to the construction site marking scheme, screw piles are installed using a manual gate (it is advisable to do this together).
4. The ends of the trunks are leveled above the ground, and the excess is cut off.
5. In unstable soils, the strength of the pile foundation is strengthened by metal strapping at the level of the base (angle or channel).
6. Install the grillage.

General construction skills, an inquisitive mind and determination are the conditions for successful installation of this type of foundation.

Useful video

Foundation on screw piles: calculation of the number of piles is clearly presented in the video below:

Instead of conclusions

Advantages screw piles are obvious:

• Possibility to use for spot development;
• exclusion of large-scale excavation work;
• addition of extensions to the main volume;
• durability;
• cost-effectiveness of the material.

Looking at them, they usually try not to notice the main problem. And it lies in vulnerability of the trunk to the rusting process. Therefore, it is necessary to pay serious attention to the protection of the metal surface during selection, purchase, storage, and also to follow the installation technology.

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When constructing any building or structure, from a skyscraper to a fence or utility block, the first thing in order and importance is the construction of the foundation. Pile foundations have proven themselves well for construction on difficult soils. Only specialists can make the correct calculation of a pile foundation, since it is necessary to take into account all the nuances of the foundation for a specific building and type of soil. All other methods will give only approximate results.

There are certain rules for calculating pile foundations and all of them must be taken into account Source fazenda.guru

Types of pile foundations

Pile foundations have several advantages over conventional strip or slab foundations, such as:

Reduced material consumption.

Possibility of installation on highly heaving soils.

Possibility of installation in areas with a large slope.

High installation speed when using screw piles. The foundation for an ordinary country house is installed in 1-2 days; there is no need to wait for the concrete to fully gain strength within 28 days.

Video description

In this video we'll look at what you need to know about concrete piles:

Piles are used in 3 types:

Hammers.

Bored. As one of the options for bored piles, so-called TISE piles are installed, with a widening at the bottom. This design feature reduces the load on the soil and allows the foundation to effectively withstand the buoyancy forces that arise during frost heaving of the soil.

Screw.

Driven elements are used extremely rarely in private construction, because... require the use of heavy construction equipment.

Source kursremonta.ru

Foundation calculation

Calculation of any type of foundation begins with determining the type of soil and groundwater level. To do this, it is best to contact a specialized organization. The “like a neighbor” option is not applicable in this case, because these parameters may vary even within a building area. Based on the recommendations of specialists, the type of foundation is selected.

The calculation methods given are approximate and do not take into account some factors that may affect the foundation being constructed.

Online foundation calculator

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

Pile foundation calculation

To calculate a pile foundation, like any other, you should calculate the load on the foundation F. To do this, add up the weight of the walls, ceilings, roof, snow load and floor load. The first 3 parameters can be calculated independently, or using special construction calculators. The snow load depends on the region in which the building is located and is determined according to SNiP 2.01.07-85 “Loads and Impacts”, the load on the floor is taken equal to 180 kg/m2 of the total area of ​​the structure.

Distribution of snow loads depending on climatic zones Source obustroeno.com

Then the load-bearing capacity of the pile is determined by the formula

P= ϒ cr*R0*S+u ϒ cf*fi*hi, Where

R0– standard soil resistance under the base of the pile

S– base area

ϒcr– coefficient of working conditions of soils under the foundation

u– section perimeter

ϒcf– coefficient of soil operating conditions on the lateral surface

fi– soil resistance on the lateral surface

hi– the depth of the pile below ground level.

The base area S of round piles is calculated by multiplying the square of the pile radius by 3.14, the perimeter by multiplying the section diameter by 3.14. The diameter of the pile is chosen based on the intended formwork material and equipment parameters, usually for private construction - 200-300 mm.

Video description

The immersion depth is chosen arbitrarily, but not less than the soil freezing depth +0.5 m, or according to the depth of the load-bearing soil layer; the groundwater level should also be taken into account.

The standard soil resistance R0, operating conditions coefficients ϒcr and ϒcf are determined from tables from SNiP 2.02.03-85.

Using such tables, experts determine the standard soil resistance, but first you need to find out the type of soil, for which a soil analysis is carried out Source stroj.umorists.ru

After calculating the bearing capacity of the supporting element, their number is calculated, for which the load on the base F is multiplied by a reliability coefficient equal to 1.2 and divided by the bearing capacity P. If the result is a non-integer number, the value is rounded up to the nearest whole number.

In some cases, it may be necessary to install additional supports, for example, when constructing a furnace in a building or installing heavy equipment.

Next, the sum of the lengths of the load-bearing walls is divided by the number of piles. In this way the pitch of the pile field is calculated. To determine the required amount of concrete solution, the volume of the piles is added up, which is calculated by multiplying the cross-sectional area by the height of the pile. The height of the pile is taken into account not to the ground level, but to a given top point.

For these calculations, you can also use the pile foundation calculator by specifying the shape of the foundation, substituting the necessary variables and selecting tabular values ​​from regulatory documents in special fields of the form.

Source martand.ru

Calculation of a columnar foundation

A columnar foundation is a pile foundation in which the piles are located on the ground surface or buried no more than 0.5 m. This type of foundation can only be used for the construction of small lightweight structures, for example a garage, utility block of a small bathhouse or country house using frame technology or from timber.

The calculation of a columnar foundation is carried out in the same way as a pile foundation, however, when calculating the bearing capacity of a column, lateral loads are not taken into account, so the formula for calculations is as follows:

P= ϒcr*R0*S

Poles can be made in a monolithic manner, like piles, or made from brick, cinder block or concrete blocks. In the second case, the cross-section is square or rectangular, and the area is calculated by multiplying the lengths of the sides. This must be taken into account when calculating using the column foundation calculator.

Source ep2nnov.ru

Calculation of foundations on screw piles

To calculate the foundation on screw piles, the same methodology is used as for bored piles, but the calculations are simplified because screw piles are a standard product, and the load-bearing capacity of the pile does not need to be calculated independently; just look at the value in the table and divide the load from the structure by this parameter. When calculating, the area of ​​the pile base is taken to be the area of ​​the blade.

To determine how much load a foundation element must withstand, you need to calculate the approximate number of piles. To do this, the length of the load-bearing walls is divided by the expected installation step of the supports, usually 2-3 m. Then, by dividing the total load of the structure on the foundation by the number of supports, the load on 1 pile is calculated. The required support area is determined by the formula

S=F=1.2/R0

– reliability coefficient, R0– standard soil resistance. Knowing the area of ​​the blade, calculate its diameter using the formula D=2√S/π, and based on the resulting value, the closest standard size is selected from the assortment.

Such data must be entered for calculations in the online foundation calculator on screw piles Source hixez.ligetok.ru.net

By using a calculator to calculate the number of piles for the foundation, you can select the most suitable and economically advantageous pile size for the given conditions by substituting various parameters. The immersion depth of the piles is determined based on the depth of the load-bearing soil layer and the groundwater level.

Video description

What are the features of concrete driven piles? We'll talk about pile foundations in our video:

Calculation of pile-grillage foundation

When building on difficult soils, in areas with a large slope, or when building from brick, aerated concrete or other blocks, a tape called a grillage is made along the top surface of the piles. It can be made monolithic from reinforced concrete or prefabricated (welded) from rolled metal. When calculating a pile-grillage foundation, the weight of the grillage itself is added to the loads from the structure. When making a grillage from rolled metal, an I-beam or a channel, the weight is calculated by multiplying the length of the tape by the specific gravity of the profile, which is indicated in the assortment. For a reinforced concrete structure, the volume of concrete is calculated (sectional area of ​​the tape per length) for a material density equal to 2400 kg/m3.

Video description

How are foundation piles made? What are the features of a pile foundation? Pros and cons of a pile foundation. How are projects calculated? Everything and more in this issue:

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

Conclusion

It is much more convenient to make calculations of any type of foundation using construction calculators, because there is no need to search for the necessary parameters in various reference books. After entering the necessary data, such as the overall dimensions and shape of the foundations, the load on the foundation, the type of soil, the depth of freezing and the groundwater level, the structural dimensions and the amount of required material are automatically calculated. However, we should not forget that the foundation is the most important element of the building, determining the strength of the entire structure, therefore all independent calculations, no matter using formulas or using calculators, are rather reference material for an approximate calculation of materials and labor costs, and, consequently, the cost of the structure . It is better to entrust accurate calculations and drawing up working drawings to specialists.

It has long been no secret that the correct choice of foundation for a house and the quality of construction determine the service life and convenience of living in it. It is necessary to calculate screw piles for the foundation at the project development stage, since without this information it is not possible to prepare an estimate or purchase tools and materials.

Design Features

Metal foundations, due to their versatility, have earned wide use among developers.

What are the features of piles?

• Design. This is a welded pipe with a sharp end, on which screw-shaped blades are welded - a fixing element that does not allow the pile to move from its seat when the soil swells, stably holding the entire building.
• carried out with precise control of the verticality of the pipe, done mechanically or manually. The main requirement is that drilling occurs to a stable soil layer. Screwing in piles is carried out regardless of the time of year and precipitation.

Indicators influencing the calculation

Calculation of screw piles for the foundation will require determining the total load on the base of the house, which consists of:

1. The masses of the building installed on the foundation. When designing a house, mass is a calculated indicator; it is determined by the materials included in the structure.
2. Additional load, including snow, furniture, equipment and people. Information for this must be taken from the approved regulatory documents SNIP No. 2.01.07-85. The payload in the form of people and furniture is assumed to be on average 150 kg per m 2.
3. Soil density. To determine this, it is necessary to carry out engineering and geodetic research, since without this work the object will not pass the state examination. The calculation is carried out in accordance with SNIP No. 2.02.03-85.
   For private construction of houses up to 3 floors, you can carry out research on your own.

After calculating the rated loads, it is necessary to take into account a safety factor of 1.2.

Types of piles

It is impossible to calculate a foundation made of screw piles for a house without first selecting their type. Each standard size is calculated for a specific type of object being built.

Dependence of pile diameter on type of load

Pipe diameter, mm	Purpose
		Under support pillars of various types of fencing.
		For light country houses.
		Heavy fences, one-story frame houses, gazebos, verandas.
		Buildings of 2 floors are frame type, as well as wooden buildings made of timber.
		Under medium-heavy houses made of foam blocks.
		For heavy brick structures and two- and three-story houses.
		Rarely used for residential buildings, more for industrial facilities.

The choice of length depends on:

• Horizontal level of the construction site: if there are significant differences in height, then a choice of piles of different lengths is possible.
• The nature of the soil. Reliable installation involves screwing to stable soil and below the soil freezing level by 25÷40 cm. In this case, the pile part should go into the ground no higher than 1500 mm.

Standardized length:

• Short: 1.65÷2.5 m.
• Long: up to 11.5 m (500 mm increments).

Calculation of the number of screw piles for the foundation: stages

You will need:

• A plan of the site to the scale on which it is necessary to plot the planned foundation with center lines.
• Tie to the communication lines: sewer pipe from the plumbing rooms and from the kitchen, drawing the diameters.
• Results of engineering-geological research.

Location:

• Single - point supports for light structures or country houses.
• Tape - sequential arrangement with a certain step.
• Custom - for heavy houses with many partitions and under each support in a frame building.

The calculation of screw piles for the foundation is carried out taking into account the layout features:

• The distance between support points must be at least 2500 mm.
• The pile should be installed in places of peak loads, which are concentrated at the center of the intersection of perpendicular lines, namely:

1. In the corners of the building.
2. At the junctions of load-bearing walls and partitions.
3. Intermediate supports must be installed evenly, including along the diagonals of the main cells of the building.
4. The size of piles and blades is determined depending on the type of load and soil characteristics.

Influence of soil on the calculation

Whatever screw piles are selected for loading is impossible without determining the bearing capacity of the soil. Thus, the soil does not always have the necessary composition to support a building without subsidence.

Important! The selected pile should not exceed the soil load capacity.

To determine, the composition of the soil is first determined and then compared with the characteristics given in the table.

Load value kg/m2 carried by different types of soil

Soil type		Soil resistance kg/cm 2 for a pile lowered by 2 m (SNIP 2.02.03-85)
	Small, wet
	Small, wet
Loams

In order to calculate screw piles for the foundation, it is necessary to determine the type of soil:

• Coarse sand: 2.5÷5 mm one grain of sand, up to 2 mm - medium. Does not change its size.
• Sandy loam is obtained by mixing sand with a small percentage (10%) of clay rock.
• If the clay content is up to 30%, the result will be loam. When wet, the mixture does not spread, but can be rolled into a ball, but when pressed, cracks appear.
• If a lump of wet soil does not crack under pressure, but is crushed plastically, the clay composition is above 30%.

Note! The higher the clay content, the higher the swelling of the soil.

• Peat is a soft and airy composition that does not imply bearing loads.

The proximity of groundwater and the degree of moisture resistance is determined by drilling a well to the depth of lowering the pile. If water has formed in a standing pit, then there is a moisture-saturated soil with a close location of the aquifer.

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