An example of calculating a pile for a 9-storey building. Pile foundation calculation of the number of piles
An online calculator for calculating a monolithic bored mortar foundation will help to calculate the dimensions of the foundation, formwork, diameter and total length of reinforcement and the volume of concrete consumed. Before you begin designing a building with such a foundation, be sure to consult with specialists how justified this choice is.
The calculations of this calculator are based on the standards given in GOST R 52086-2003, SNiP 3.03.01-87 and SNiP 52-01-2003 “Concrete and reinforced concrete structures”.
Columnar and pile foundations are varieties of foundations in which columns or piles are used as supports. They are immersed in the soil to the required depth, and their upper parts are connected by a solid reinforced concrete structure (grillage), which does not come into contact with the ground. With the columnar and pile version of the grillage foundation, the depth of installation of the supports differs.
The grillage structure makes sense where the soil is not suitable for the usual placement of the foundation (soft soil, heaving, or freezing to a considerable depth). Since piles become clogged under any climatic conditions, the grillage foundation is especially relevant for regions with low temperatures and harsh climates. Other advantages of the grillage technology are a high speed of construction and a low need for earthwork. It is enough to drill holes and complete the installation of ready-made piles.
Many parameters of the grillage foundation may vary. This is the form and materials of piles, methods of action on the ground, installation methods, the shape of the grillage. Each case of the grillage foundation must take into account design loads, climatic conditions, soil specifics and other features of the terrain and future construction. To clarify all these points, you need to carry out the necessary measurements and calculations, if necessary, invite experts. Savings on initial calculations can result in serious consequences in the future. To avoid this, first of all, we recommend that you carefully study this calculator. In it, you will be able to determine future expenses and, using the example of a standard design, determine the components of the planned foundation.
When filling out the fields of the calculator, check the additional information that appears when you hover over the question icon.
At the bottom of the page, you can leave a response, ask a question to the developers or offer an idea to improve this calculator.
Clarification of calculation results
Total grillage length
The total perimeter of the foundation, including internal partitions.
The size of the sole of the grillage
The area of \u200b\u200bthe lower part of the grillage, which needs waterproofing.
Area of \u200b\u200bthe external lateral surface of the grillage
The area of \u200b\u200bthe lateral surfaces of the outer side of the foundation, requiring insulation.
Concrete volume for grillage and pillars
The total amount of concrete that will be needed to fill the foundation with the given parameters. Actual demand may be higher due to seals during pouring, and the volume of concrete actually delivered may be less than ordered. Therefore, we recommend ordering concrete with a 10 percent margin.
Concrete weight
Approximate concrete weight at medium density.
The load on the soil from the foundation at the base of the pillars
In the calculation, the total weight of the structure is taken into account.
Minimum diameter of longitudinal reinforcement bars
It is calculated according to the norms of SNiP. The relative content of longitudinal reinforcement in the section of the grillage tape is taken into account.
Minimum number of rows of reinforcement grillage
To counteract the natural deformation of the grillage tape under the action of compressive and tensile forces, it is necessary to use longitudinal rods in different grillage belts (at the top and bottom of the tape).
Total weight of fittings
Weight of rebar rods combined.
Reinforcement overlap
For lashing reinforcement bars, use this value.
Length of longitudinal reinforcement
Total length of reinforcement including overlap.
Minimum number of longitudinal reinforcing bars for poles and piles
The required number of longitudinal reinforcing bars for each column or pile.
Minimum rebar diameter for poles and piles
The minimum allowable diameter of the longitudinal bars of the reinforcement, ensuring the strength of the posts or piles.
Minimum diameter of transverse reinforcement (clamps)
It is determined based on the norms of SNiP.
Maximum pitch of transverse reinforcement (clamps)
It is calculated so that when pouring concrete the reinforcing cage is not displaced or deformed.
Total weight of clamps
The total weight of the clamps that will be required during the construction of the entire foundation.
Minimum board thickness for supports every meter
The required thickness of the formwork boards with the given parameters of the foundation and the given step of the supports. It is calculated based on GOST R 52086-2003.
The number of boards for formwork
The number of boards with a standard length of 6 meters that will be required for the construction of the entire formwork.
Formwork perimeter
The total length of the formwork, taking into account the internal partitions.
Volume and approximate weight of formwork boards
Such a volume of boards will be required for the construction of formwork. The weight of the boards is calculated from the average density and humidity of conifers.
As a rule, before starting the construction of buildings on a suburban area, a study is made of the underlying soils. It is depending on the soil should choose the type of foundation for the construction of a house, garage or bath.
If you got a good site in a high place with sandy dry soils that are not prone to heaving phenomena, then you can lay a shallow strip foundation. On soft soils, a rigid structure of a monolithic reinforced concrete foundation can be used.
But, if the construction site is formed by heaving soils, then the optimal choice will be the foundation of deep laying, based on a foundation not subject to seasonal freezing.
In this case, the foundation can be either strip or columnar (pile). The tape is used for massive capital buildings and requires much more building materials, which leads to an increase in construction costs.
As a rule, for a low-rise individual suburban construction, a columnar foundation is quite enough. Today, there are several different varieties of columnar foundations, depending on the materials used.
In the previous publication, we examined in detail how to build the foundation of TISE. But its construction is impossible, without preliminary calculation and determination of the required number of piles, their diameter and depth.
Let's take a closer look at how to independently calculate the number of piles for the foundation of a house or bath in a suburban area.
Foundation calculation algorithm
The main task of calculating any foundation is to determine its height, width, bearing area and structure depending on the weight of the building and the soil to which this weight will be transferred through the designed foundation.
Therefore, the calculation algorithm is reduced to calculating:
- building weight;
- snow load;
- operational load;
- the area of \u200b\u200bsupport of the foundation, depending on the resistance of the soil.
Building weight determination
Having in hand a building project, you can find out its weight. Having added up the mass of all structural elements used in the construction given in the specifications for the drawings.
If the weight of any structures is not indicated, it can be determined using the table of the specific gravity of building materials:
The proportion of building materials |
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Name |
Unit. |
Qty |
Concrete |
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Reinforced concrete |
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Concrete on rubble or gravel |
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Aerated concrete, foam concrete |
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Solutions |
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Cement Sand |
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Cement sand with lime |
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Calcareous sand |
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Brick |
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Earthenware |
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Silicate |
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Ceramic |
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Wood |
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Conifers (pine, spruce) |
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Glued plywood |
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Fiberboard plate |
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Chipboard plate |
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Bulk materials |
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Expanded clay gravel |
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Building sand |
Also, for approximate calculations, you can use the table of the weight of building structures depending on the material:
The proportion of building structures |
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Name |
Unit. |
Qty |
Walls |
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Frame walls with efficient insulation and lightweight cladding |
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Log house made of logs or timber |
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From aerated concrete blocks D600 |
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From cinder blocks D1200 |
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Hollow brick |
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Solid brick masonry |
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Overlap |
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Wooden on wooden beams |
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Wooden on steel beams |
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Metal tile or ondulin with a slope of slopes up to 27 ° |
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Roofing material in 2 layers with a slope of up to 10 ° |
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Slate at a slope of 30 ° |
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Ceramic tile up to 45 ° |
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Sheet metal |
To calculate the weight of the walls, you need to add the weight of the material from which they are built (for example, the weight of all bricks) with the weight of the mortar used for the construction of the mortar, as well as the weight of the finish (plaster or siding).
The weight of the floors is the weight of the beams, slabs, insulation, flooring and ceiling decoration of the underlying floor.
You should also consider the weight of the foundation itself, which, depending on the solution, is:
The volume of mortar and reinforcement on the foundation device is determined depending on the depth of laying, depending on the depth of freezing:
The concept of operational load includes all furniture that is supposed to be installed in the rooms of a building under construction, as well as various equipment. But, since, in comparison with the weight of building materials of the building, the weight of the furniture is very small, for approximate calculations it can be neglected.
Snow load
It is determined on the basis of the values \u200b\u200bof the thickness of the snow cover in the winter season according to SNiP "Construction Climatology", as well as depending on the angle of the roof slopes.
A map of average snow cover weights is presented below:
When calculating a single-pitched roof, a coefficient of 1 is used, and when determining the load on a gable roof with an angle from 26 to 60 degrees - 1.25.
Determination of the number of piles
The bearing capacity of piles depends on the resistance of the soil and the bearing area of \u200b\u200bthe pile itself.
Knowing the weight of the structure and the type of base soil, you can determine how many piles and what diameter is required for the foundation.
For an approximate calculation, you can use the following table:
Soil type |
Soil resistance, kg / cm 2 |
Bearing capacity of piles depending on the diameter of the support (mm), tons |
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Large sand |
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Medium sand |
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Fine sand |
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Dusty sand |
Calculator
Number of piles:
Pile Diameter:
Pile Length:
Use the online pile calculator on our website. In addition to the required quantity, you can also find out their preliminary diameter and length.
Calculating a pile field online is quite simple. To do this, you do not need to have a special education and read literature. You only need to enter data into existing columns.
- Indicate the length of the sides of your structure, choosing from 3 to 15 meters in shape.
- Indicate the type of structure - house, garage, domestic building, etc.
- Indicate "number of storeys" if appropriate columns appear.
Filling in the columns, pay attention to the fact that the house with an attic will be considered a one and a half floor building. - Choose the material of your building.
- Indicate the type of soil on the site.
- Indicate the number of corners of the planned house.
- Indicate the height of the basement of the proposed options.
- Note if you intend to install a fireplace / stove.
- Click "Calculate."
After a few seconds, the result of calculating the required number of piles for your object will appear.
Let's look at an example.
There is a peat plot with a peat depth of 3 meters. You decided to build a wooden house (beam 150x150), an area of \u200b\u200b10 by 10 meters. The house is planned in an original form with nine corners and an attic. At a height of 50 cm above the ground will be located floor. To keep you warm in winter, it was a decision to install a fireplace in the house.
After all the data were entered, the calculator for counting the number of screw piles gave us the result - 32 piles with a diameter of 108 mm and a length of 4.5 meters.
Of course, this calculation is preliminary. It serves as a guide when planning the budget and further ordering. For a more accurate result, a specialist’s visit to the object is necessary for a detailed inspection of the site for the planned development, where all factors will be taken into account.
On-site self-settlement
The same calculation can be done independently and without using a calculator. The result obtained in this way is in most cases less accurate. You will need to determine the type and density of the soil, analyze the natural topography, determine the distance at which the more dense layers of soil are.
Another option, how you can find out the required number of piles, is to calculate them according to the plan of the first floor. Here you need to calculate the number of corners and joints of external walls with load-bearing partitions. Piles should be located in these places, they should go along the perimeter in increments of not more than three meters. If you plan to install a fireplace, then, depending on its weight, you need to install from one to four piles for it.
Carry out the calculation on the calculator and according to the plan of the first floor and compare the results.
As a rule, specialists begin designing a pile-screw foundation based on the number of piles, choosing their parameters and placing them on the diagram from the outside and inside of the house. Also, to guarantee quality work, it is necessary to carefully measure the distance between the piles. The whole process can be performed independently, especially since there is a simplified calculation of the foundation using piles.
Calculation Methods
The main elements of this type of base are screw piles made of metal, the length and diameter of which may vary depending on the technological requirements and the expected load that they will have to withstand. In specialized companies and design offices, you can order a professional complex calculation of a pile-screw base, in which various parameters and design features will be entered, as well as the bearing capacity of the soil in the area allocated for the construction of the future house. We suggest using a simplified version and calculating screw piles, based on practical experience in the construction of such structures.
Grill options for screw piles
Determination of the diameter of the supports
Screw piles, which are used when installing the foundation for residential and utility buildings, have a diameter of 57, 76, 89 and 108 mm. This parameter is selected depending on how much the finished structure will have:
- 57 mm - used for the construction of the simplest and lightest structures (fences and fences from the netting netting);
- 76 mm - choose as the basis for lightweight outbuildings or fences made of wood or corrugated board. The bearing capacity of such elements does not exceed 3000 kg;
- 89 mm - used where the bearing load does not exceed 5000 kg. This is an excellent solution for the construction of a one-story building (frame or panel), baths, summer kitchens, sheds and massive fences;
- 108 mm - the site is under construction for the construction of a house from foam blocks, a wooden beam, a frame (1-2 floors) with a small weight. The bearing capacity of screw piles of this diameter reaches 7000 kg.
The diameter of the elements depends on the weight of the building
Factors affecting the length of the supports
The strength of the future structure depends on the correct determination of the length of piles, and if these important elements of the foundation are short, the house can sag under its own weight after it is put into operation. The length of the piles is determined taking into account the analysis of soil and landscape, namely:
- Soil density.
- The difference in height between different points of the site.
Soil density
Depth of support
Soil analysis is best done based on geological studies of the area. If studies of soil characteristics have not been carried out in a given territory, then a simplified method for determining its density can be used.
So, you need to dig a shallow ditch (up to 1 m) at the bottom of the site. If you see clay mass or sand at such a depth, then the choice is better in favor of piles up to 2.5 m long. If you find rocks with low density (peat), quicksand or groundwater, you will have to continue to deepen until you reach hard rock. Piles are installed here, the length of which is equal to the length of the drill.
Here is a table of the density and bearing capacity of various soils.
Sand (large fraction) | 6 | 5 |
Sand (middle fraction) | 5 | 4 |
Sandy loam (dry) | 3 | 2.5 |
Plastic sandy loam (wet) | 2.5 | 2 |
Sand (fine fraction) | 4 | 3 |
Wet sand (fine fraction) | 3 | 2 |
Clay | 6 | 2.5 |
Wet clay | 4 | 1 |
Loam | 3 | 2 |
Wet loam | 3 | 1 |
The difference between the heights of the site
As mentioned earlier, in order not to make mistakes with piles and correctly calculate their length, it is necessary to determine the difference in height of different points of the site. If you are convinced that such a difference exists and, according to the density of the soil, piles 2.5 m long are suitable, then they must be mounted in the very top row.
Those supports that will be fixed in the lowlands should be longer by the difference in height between the points of their installation. The difference is calculated using a water level or level using a plumb line and a tape measure. With a significant difference in height (more than 0.5 m), it is recommended to add 50 cm to the obtained length of piles for the foundation, since in the lowest places it may not reach up to 20 cm of their height.
Height difference
Calculation Method
The calculation of the number of screw piles is carried out taking into account the dimensions and weight of the house, which will be installed on the foundation. As a rule, the distance between piles can be:
- up to 2 m, if a structure of aerated concrete and foam concrete blocks or slabs is being built;
- up to 3 m, if it is planned to build a wooden house from timber, logs, etc .;
- up to 2.5 m - also choose for wooden structures. They also work with such piles in regions where there is a large wind load;
- up to 3.5 m - for the construction of lightweight fences and fences.
Construction of a house from a bar
In order to correctly determine the number of supports for a pile-screw foundation, the following operations should be carried out:
- to draft a future foundation or first level of construction;
- place screw supports on every corner of the future building;
- install piles where the load-bearing partitions of the house intersect;
- between the piles located now it is necessary to install additional piles around the perimeter of the bearing walls so that the distance from one to the other element does not exceed what was fixed earlier (taking into account the weight and type of construction);
- the remaining space for the foundation is filled with piles so that the distance between adjacent supports does not exceed the distance specified in the calculations (2 - 3 m);
- where the stove or fireplace will be installed, provide for at least a pair of screw supports, again, given the size of the heating structure, otherwise the critical load on the foundation cannot be avoided;
- in case a terrace or any other extension will be equipped, the fixation points of the supporting elements are indicated according to the previously agreed principle, taking into account the optimal step distance;
- now that the distance between the piles is determined, it remains to count all the screw supports applied to the plan.
We calculate the grillage
The pile base can be constructed from one support on which the lower strapping of the structure is laid.
In order for the load on the supports from the weight of the structure to be distributed more evenly, resort to the manufacture of grillage.
A grillage is called a beam or reinforced concrete slab, horizontally connecting the tops of each screw element. Pile and grillage foundations are equally well suited for the construction of wooden and foam block buildings. The tape grillage can be monolithic or prefabricated, the main thing is that it be poured out of concrete, whose brand is not lower than 150.
In order for the grillage to be correctly constructed and create a strong bond between the screw elements, it is necessary to correctly calculate its dimensions. There are a number of special calculations, but we will limit ourselves to the minimum dimensions of the adhesive tape:
Foundation with reinforced concrete grillage
- Height - 30 cm.
- Width - 40 cm.
To give the grillage the necessary rigidity, it must be strengthened by longitudinal and transverse reinforcement (in diameter 10-12 mm). The rods are connected using wire according to the principle of armopoyas. The distance from the reinforcement to the edge of the grillage should be at least 2.5 cm so that the metal rods are completely sealed with concrete mortar and not subjected to corrosive processes.
The connection of the grillage with the supports can be rigid when its reinforcement is connected with the rods of the piles, or loose when the grillage without additional garter rests on the supports of the foundation. In both cases, the load between piles is distributed evenly.
Adhering to a professional approach to construction work, the necessary calculations should be made during the design process.
They will allow reduce time and effort to complete the entire volume of tasks and significantly save materials.
What is it for?
A pile foundation made of metal supports with blades at the end is the most economical and popular type of foundation for complex terrain.
Technological advantages make it possible to finish its device in 3 days, and the foundation will serve at least 100 years.
To make this happen, you need to evenly distribute the bearing load of the structure being built, take into account the characteristics of the soil, the level of freezing and occurrence of groundwater.
As a result of the calculations, you can get:
- the height of the screw piles;
- the depth of their laying;
- optimal diameter of the supports;
- total amount;
- total cost of expenses.
Conclusion:calculation of the foundation saves time and money, guarantees the durability of the structure.
Calculation sequence
A common method for calculating screw piles SNiP 2.02.03-85 relies on geodetic data for a specific building site, which includes information about:
- site relief;
- soil composition and density;
- groundwater level;
- soil freezing level;
- the volume of seasonal precipitation characteristic of a given climatic zone.
Tip: if it is not possible to conduct a geodetic survey, the calculations are guided by the minimum design load.
To calculate the pile-screw foundation, 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 the tables of the specific gravity of materials (in kg);
- safety factor (k) as a correction of the load value (it must be multiplied by R);
- soil bearing capacitydetermined by the table of averaged loads on screw piles;
- pile heel area depending on the diameter (according to the table);
- maximum permissible load (S) on one pile (according to the table).
The obtained data is substituted into the formula, according to which the calculation of the foundation on screw piles is performed: K \u003d P * k / S
Safety factor (k) consistent with the number of piles:
- k \u003d 1.4 - for 11-22 pcs;
- k \u003d 1.65 - for 6-10 pcs;
- k \u003d 1.75 - for 1-5 pcs.
Each pile carries a load proportional to the total load of the structure.
Using the above formula, the coefficient and screw piles for the foundation, the calculation of the load and subsequent construction are quite simple.
For the final calculation, it is necessary to distribute the load under the bearing walls and areas of increased pressure on the foundation, considering:
- type of piles (hanging or racks);
- indicator of roll effort.
Reference! For accurate calculations and professional design of the pile foundation in the free access of the Internet there are computer programs StatPile and GeoPile. They are accompanied by a guide and 10 specific calculation examples.
Parameters
The calculation of the screw foundation and the load on it consists of determining the following parameters:
1. The mass of the building itself (in kg) - constant value:
- walls and partitions;
- overlapping;
- roof.
2. Extra weight - temporary loads:
- the weight of snow falling on the roof;
- operational weight of the contents of the house: furniture, equipment, finishing materials, including people (average - 350 kg / m²).
3. The correct calculation of the load on the pile-screw foundation is impossible, if you do not take into account dynamic loads (short-term):
- created by gusts of wind;
- resulting from the settlement of the structure;
- arising from temperature differences.
About how the screw foundation is calculated is additionally described in the video below:
Types of Screw Piles
By the form of piles there are:
- broad-bladed cast tip (at the cone ᴓ6 ... 14mm) - for low-rise buildings on simple soils;
- multi-blade with several blades at different levels - for increased loads in complex soils;
- variable pitch piles - for specific tasks;
- narrow-lobed cast tooth tip - for stony soils and permafrost.
Reference: trunks from suture pipes with welded blades have less reliability.
Specifications
The technical characteristics of screw piles include:
- barrel length and material;
- barrel diameter;
- type of blades, method of their connection with the pile body.
Diameter
Diameter of pile trunks selected from the standard series, correlating with the calculated load:
- ᴓ89mm (blade ᴓ250mm) - under a bearing load of not more than 5 tons (frame-panel buildings on the 1st floor);
- ᴓ108mm (blade ᴓ300mm) - under a bearing load of up to 7 tons (houses made of timber, foam blocks, two-story frame);
- ᴓ133mm (blade ᴓ350mm) - under a bearing load of up to 10 tons (structures made of brick, aerated concrete, channel).
Length
Pile length selected, based on indicators of soil density (according to the table) and elevations at the construction site:
- when loam is 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, which has reached dense layers;
- at elevation elevations, the length of piles may differ by 0.5 m for different sections.
The number of supports and the distance between them
Optimum distance between supports:
- 2-2.5 m - for wooden frames and block structures;
- 3 m - for houses made of timber and logs.
Important: to ensure reliability, the base of the structure should not rise above the ground higher than 60 cm, and the length of the pile should have a margin of 20-30 cm.
After calculating the formula K \u003d P * k / Snecessary distribute the position of piles in the perimeter to balance the load they take:
- for every 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 from the side of the balcony or mezzanine.
Note! Objective conditions may require an increase in the number of piles compared with the calculated one - such a margin of safety will allow you not to be afraid of the changes that occur during operation.
Grillage
The grillage serves to evenly distribute the load on the base structure. Regardless of the type of grillage (whether it is prefabricated or monolithic, high or low), for its reliability it is necessary to calculate the following parameters:
- the strength of the foundation;
- punching force at every angle;
- bending force.
As with a pile foundation, this intellectual work can be done with computer programs StatPile and GeoPile. There is an easier option - use the standard of individual construction, which sets:
- connection of supports with grillage - rigid or free;
- the depth of entry of the pile head into the grillage is at least 10 cm;
- grillage position 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 and more;
- reinforcement (longitudinal and transverse) with a bar ᴓ10-12 mm.
Important! In unstable soils, the strength of the pile foundation will be strengthened by a metal strapping at the level of the base (corner or channel).
Example of calculating a pile-screw foundation
The following example describes in detail how to calculate the foundation on screw piles for building a frame house.
Initial data - pile-screw foundation 6x6:
- a typical frame-structure 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 60⁰;
- frame material - timber 150x150;
- wall material - sandwich panels;
- grillage material - timber 200x200.
1. Determine the area each wall:
- bearing - 18 m² * 4 \u003d 74 m²;
- partitions - 9 * 2 + 12 \u003d 30 m².
2. We determine the load of the wallsusing the table:
- for load-bearing walls - 50 kg * 74 \u003d 3700 kg;
- for partitions - 30kg * 30 \u003d 900 kg;
- total 3700 + 900 \u003d 4600 kg.
3. Gain weight on 36 m² of area:
- basement - 150 kg * 36 (area of \u200b\u200bthe house) \u003d 5400 kg;
- attic flooring - 100 kg * 36 \u003d 3600 kg;
- roofs 50 kg * 36 \u003d 1800 kg;
- in the end - 4600 + 5400 + 3600 + 1800 \u003d 15400 kg.
4. We add extra weight and dynamic loads. (weight of snow infusion \u003d 0):
- 350 * 36 + 15400 \u003d 28000 kg.
5. Choose a safety factor 1,4.
6. Take from the table maximum heel load (ᴓ300) of one pile element: it is equal (according to the table) to 2600 kg, with an estimated soil resistance of 3 kg / cm² (medium density soil, with deep groundwater and freezing no more than 1 m).
7. Substitute the values \u200b\u200bin the formula K \u003d P * k / S- 28000 * 1.4 * 2600 \u003d 15 (pcs).
In this case, we will install 12 piles at angles and intersections, and 3 we will use to reinforce areas with increased load.
Installation procedure
It happens that the soil under the foundation is not complicated by quicksand or rock.
In such cases installation of a screw base of a pile type is quite affordable for the layman:
- The most time consuming and responsible part is to make calculations.
- Prepare the necessary material and tools.
- According to the layout scheme of the construction site, screw piles are installed using a manual gate (it is advisable to do this together).
- The ends of the trunks are leveled above the ground, the excess is cut off.
- In unstable soils, the strength of the pile foundation is reinforced with metal strapping at the base level (corner or channel).
- Install the grillage.
General construction skills, an inquiring mind and determination - these are the conditions for successful work on installing the foundation of this type.
Please note that this calculation of the foundation is simplified and cannot take into account all the individual characteristics of your project. To clarify them, our specialist will contact you shortly.
The calculator does not take into account the internal bearing wall of the building.
Our service allows you to pre-calculate the screw foundation in order to estimate its cost in advance. If you require installation work, a team of experienced builders will be sent to the facility, who are fully equipped with the necessary equipment, including generators and water tanks. After you indicate the place for your future pile foundation, the builders will begin installation work. You have the opportunity to accept work at the end of the day and discuss with the foreman questions of interest to you regarding the pile foundation. Installation of the foundation up to 25 piles lasts only 1 day. On the foundation made by our experts, we give a guarantee for a period of 10 years.
An accurate calculation, during which the cost of screw piles for the foundations of houses and other structures is determined, is performed online based on the parameters entered by the customer. A convenient and intuitive service is provided for this.
To calculate the cost of the foundation, enter the necessary data on the soil, dimensions, type of structure and its parameters in the calculator. If you have additional questions, ask our specialists. They will help you understand and correctly calculate the screw foundation. Contact numbers are listed at the top of the page of our site.
The number of piles. Typically, the calculation is based on the assumption that the distance between piles cannot exceed 3 meters. Thus, nine piles are sufficient for the foundation of a small one-story house 6x6 meters. However, for a two-story building, it is better to place them at a distance of 2-2.5 meters from each other.
The diameter of the pile. It all depends on the potential load of the foundation. For pavilions, screw piles with a diameter of 89 mm are suitable, but for the house you need to choose the classic 108 mm.
Tip Type. The tip of the pile can be welded or cast. A specific option is selected based on the characteristics of the soil. Supporting elements with a cast tip will cost a little more, but their cost is compensated by high anti-corrosion characteristics.
Length. The cost of screw piles, of course, is directly affected by their length. In most cases, it is 2.5 meters, however, a specialist must conduct a trial drilling to determine the exact values \u200b\u200bof the lengths of piles for a particular foundation.
The presence and size of the heads. The heads are welded over the piles and serve as a support for the slab or beam of the grillage.
At the next stage, the cost of tying is determined. Tying piles may be necessary if necessary to ensure additional stability in the horizontal plane. For example, tying is advisable if the height of the piles above the ground exceeds 50 cm or in the case of unstable peat soils. However, even in the general case, tying piles is never superfluous, since this operation significantly increases the structural strength of the foundation.
In the final determination of the cost of work, additional factors are taken into account: the need for installation services, the distance to the facility (fuel costs), the availability of electricity at the facility (compensation for the cost of delivery and operation of a portable diesel generator is necessary).
It has long been no secret that the correct choice of the foundation for the house and the quality of construction determine the service life and convenience of life in it. Calculation of screw piles for the foundation is necessary even at the stage of project development, since without this information it is not possible to prepare an estimate, purchase tools and materials.
Design features
Metal for the foundation, due to its versatility, has earned widespread use among developers.
What are the features of piles?
- Design. This is a welded pipe with a sharp end, on which blades in the form of a screw are welded - a fixing element that does not allow the pile to move from its seat when swelling the soil, holding the entire structure stable.
- It is carried out with a clear control of the verticality of the pipe, is made mechanically or manually. The main requirement is that drilling takes place to a stable soil layer. Piling is carried out regardless of the season and precipitation.
Indicators affecting the calculation
Calculation of screw piles for the foundation will require determining the total load on the base of the house, which consists of:
- Masses of construction, installed on the foundation. When designing a house, mass is a calculated indicator, it is determined by the materials embedded in the design.
- Extra load, including snow, furniture, equipment and people. Information for must be taken from the approved regulatory documents of SNIP No. 2.01.07-85. The payload in the form of people and furniture is taken on average 150 kg per m 2.
- Soil density. To determine, it is necessary to carry out engineering and geodetic studies, since without these works the object will not pass 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, research can be done on their own.
After the calculation of the rated loads, it is necessary to take into account a safety factor of 1.2.
Types of piles
It is impossible to calculate the foundation of screw piles for a house without first choosing their type. Each size is calculated for a certain type of facility being built.
Pipe diameter mm |
Appointment |
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Under the supporting posts of various types of fencing. |
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For light country buildings. |
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Heavy fences, single-storey frame houses, gazebos, verandas. |
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Buildings on 2 floors of frame type, as well as wooden buildings made of timber. |
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Under the house of moderate severity of foam blocks. |
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For heavy brick structures and two-, three-story houses. |
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Rarely used for residential buildings, more for industrial facilities. |
The choice of length depends on:
- Horizontal construction site: if there are significant differences in height, then it is possible to choose piles of various lengths.
- The nature of the soil. A reliable installation involves screwing to a stable soil and below the level of soil freezing by 25 ÷ 40 cm. In this case, the pile part should go into the soil no higher than 1500 mm.
Length standardized:
- Short: 1.65 ÷ 2.5 m.
- Long: up to 11.5 m (pitch 500 mm).
Calculation of the number of screw piles for the foundation: stages
You will need:
- The plan of the plot on the scale on which it is necessary to apply the planned base with center lines.
- Bind to communication lines: sewer pipe from plumbing rooms and from the kitchen, with a drawing of diameters.
- Results of engineering and geological research.
Location:
- Single - point supports for light structures or country houses.
- A tape is a sequential arrangement with a specific step.
- Scrub - for heavy houses with many partitions and under each support in a frame structure.
Calculation of screw piles for the foundation is carried out taking into account the features of the layout:
- The distance between the fulcrum must be at least 2500 mm.
- The pile should be installed in places of peak loads, which are concentrated in the center of intersection of perpendicular lines, namely:
- In the corners of the building.
- At the joints of load-bearing walls and partitions.
- Intermediate supports should be installed evenly, including along the diagonals of the main cells of the building.
- The size of piles and blades is determined depending on the type of load and soil characteristics.
The effect of soil on the calculation
Whatever screw piles were chosen for load is impossible without determining the bearing capacity of the soil. So, the soil does not always have the necessary composition, which allows the building to withstand without subsidence.
Important! The selected pile should not exceed the value of the withstand load of the soil.
For determination, the soil composition is first determined, and then compared with the characteristics given in the table.
Type of soil | Ground resistance kg / cm 2 for a pile lowered to 2 m (SNIP 2.02.03-85) |
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Shallow, wet | |||
Shallow, wet | |||
Loam | |||
In order to calculate the 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 sandy clay with a small percentage (10%) of clay.
- If the clay content is up to 30%, loam will be obtained. When wet, the mixture does not spread, but can be rolled into a ball, but when pressed, cracks appear.
- If a lump of moist soil does not crack under pressure, but is crushed plastic, the clay composition is above 30%.
Note! The higher the clay content, the higher the swelling of the soil.
- Peat - soft and airy composition does not imply bearing loads.
The proximity of groundwater and the degree of moisture resistance is determined by drilling a well to a depth of lowering piles. If water has formed in a standing hole, then there is a moisture-saturated soil with a close location of the aquifer.