When constructing any building, it is important to correctly calculate the foundation. Calculate the foundation You can do this with the help of specialists or independently using a foundation calculator. Let's consider the most important points, this includes load calculation, the volume of the foundation pit and tips that need to be taken into account when creating a house foundation project. To calculate the foundation, you can use the foundation calculator.

1. Calculate the weight of the house structure.

An example of calculating the weight of a house structure: You want to build a house with a height of 1 floor, 5 m by 8 m, also an internal wall, the height of floor to ceiling is 3 meters.

Let's substitute the data and calculate the length of the walls: 5+8=13 meters, add the length of the inner wall: 13+5=18 meters. As a result, we get the length of all the walls, then we calculate the area, multiply the length by the height: S = 18 * 3 = 54 m.

We calculate basement floor area, multiply the length by the width: S=5*8=40 m. The attic floor will have the same area.

We calculate roof area, multiply the length of the sheet by the width, for example, a sheet of roofing has a length of 6 meters, and a width of 2 meters, as a result the area of ​​one sheet will be 12 m, in total we will need 4 sheets on each side. In total, you will get 8 roofing sheets with an area of ​​12 m. The total area of ​​the roofing covering will be 8 * 12 = 96 m.

2. Calculate the amount of concrete required for the foundation.

To begin the construction of a building, you need to draw up a project for the foundation of a private building, from which you can calculate the required amount of building materials for the construction of the structure. In our case, it is necessary to calculate the amount of concrete to create the foundation. The type of foundation and various parameters serve to calculate the amount of concrete.

3. Calculation of foundation area and weight.

The most important factor is the soil under the foundation; it may not withstand high loads. To avoid this, you need to calculate the total weight of the building, including the foundation.

An example of calculating the weight of a foundation: You want to build a brick building and have selected a strip foundation for it. The foundation goes deep into the ground below the freezing depth and will have a height of 2 meters.

Then we calculate the length of the entire tape, that is, the perimeter: P= (a+b)*2=(5+8)*2=26 m, add the length of the internal wall, 5 meters, and in the end we get the total length of the foundation 31 m.

Next we do volume calculation To do this, you need to multiply the width of the foundation by the length and height, let’s say the width is 50 cm, which means 0.5 cm * 31 m * 2 m = 31 m 2. Reinforced concrete has an area of ​​2400 kg/m3, now let’s find the weight of the foundation structure: 31m3*2400 kg/m=74 tons 400 kilograms.

The supporting area will be 3100*50=15500 cm2. Now we add the weight of the foundation to the weight of the building and divide it by the supporting area, now you have a load of kilograms per 1 cm 2.

Well, if, according to your calculations, the maximum load exceeded these types of soils, then we change the size of the foundation to increase its supporting area. If you have a strip foundation, then you can increase its supporting area by increasing the width, and if you have a columnar foundation, then increase the size of the column or their number. But remember, this will increase the total weight of the house, so it is recommended to re-calculate.

A slab foundation is a monolithic foundation that gives the structure stability and durability. A reinforced concrete slab, which is laid under the entire area of ​​the building, serves as a reliable support for a residential building or outbuilding. The minimum volume of excavation work, low coefficient of pressure on the ground, as well as ease of arrangement are the objective advantages of a monolithic slab, a key element of the foundation of this category. Professional reinforcement of the foundation slab guarantees the foundation strength and resistance to significant mechanical loads. A competent calculation of a slab foundation will help you quickly and accurately complete the online monolithic slab foundation calculator.

Advantages of an online calculator for slab foundations

• Performs calculations of the foundation slab taking into account all technical and operational characteristics of concrete, formwork and reinforcement cage.
• Saves effort and time when developing a successful construction strategy, as well as drawing up an estimate for the arrangement of a slab foundation.
• 2D and 3D visualization options allow you to visually assess the adequacy of calculation operations in real time, and, if necessary, make appropriate amendments to the project.

Calculation of reinforcement for a monolithic slab

• Determination of the minimum diameter of reinforcement mesh elements, which must comply with SNiP rules.
• Calculation of the minimum permissible cross-section of vertical reinforcement cage bars.
• Specifying the average cell size of the reinforcing mesh, as well as determining the amount of overlap.
• Calculation of the number of rows, the diameter of the clamps, as well as determination of the total weight of the reinforcement cage, taking into account the overlap.

Additional functions of the online calculator

• Calculation of the number, length and thickness of formwork boards taking into account the requirements of GOST R. 52086-2003.
• Determination of the metric characteristics of the slab, its base and side faces to calculate the amount of insulation.
• Calculation of the proportions of sand, cement and crushed stone in hand-made concrete, which will be required to form a slab foundation.

Simplify the process of calculation and measurement operations as much as possible today. Use the online slab foundation calculator for free right now!

In construction, there are a large number of types of foundations, different in their design features, construction methods and source materials.

The monolithic type is divided into subtypes: shallow and deep.

When building a small house, a monolithic foundation can only be equipped with additional labor, or, in extreme cases, the help of friends.

Construction of a monolithic foundation

The great advantage of the monolithic type of base is its unique ability to be installed on absolutely any surface. Even if the surface of the construction site is soil that is uneven in structure, with areas of peat bogs and sand cushions, then a monolithic foundation, represented by a concrete slab and formwork, can withstand any load of the future building.

The monolithic foundation is very resistant to loads, even those that arise due to soil subsidence. This feature is ensured by a large support area, which significantly reduces the pressure on the soil.

The negative characteristics of a monolithic base include:

• high consumption of expensive materials;
• massiveness of the structure;
• large labor costs during construction of the structure.

Unlike other types of foundation, a monolithic foundation requires reinforcement throughout the entire structure. It is usually carried out by reinforcing the surface. This approach also allows you to cope with possible loads arising from soil movement.

Traditionally, a monolithic base is used in the construction of those buildings in which the functions of the base are taken over by the surface of the first floor.

Attention ! The use of monolithic foundations makes it possible to implement a large number of architectural projects of modern buildings.

Calculation of a monolithic foundation

The level of strength of the house and the duration of its operation depend on how accurate the calculation results are. For all the main indicators of a monolithic foundation, it is worth carrying out calculations at the development stage of a construction project.

First of all, we determine the level of load that the selected type of foundation and the soil on which the foundation will press can withstand. There are temporary and permanent types of load. Constants include the weight of the foundation, roof and walls, and also take into account the weight of furniture, equipment located in the house, and the people living in it.

Variable loads are somewhat more difficult to calculate, since these are the weather and climatic conditions that prevail on the territory of the constructed building.

Before starting to calculate the foundation, experts calculate the area of ​​support on which it will be located. It is imperative to calculate the mass of the monolithic foundation, since exceeding the load on the ground can lead to a rather disastrous situation.

Important ! When carrying out calculations, experts pay special attention to the building materials that will be used in the construction of the house. This approach makes it possible to correctly assess the real load and correctly distribute it over the entire area of ​​the house.

Thickness of monolithic foundation

Calculation of the thickness indicator should be carried out taking into account:

• soil indicators;
• geodesy of the site;
• technological features of the construction project.

Taking these parameters into account, the thickness and area of ​​the monolithic base are calculated. Let us consider the features of using a monolithic base depending on the thickness index.

With a minimum value of 15 cm, a monolithic base is suitable only for light, small buildings erected on non-heaving soil. The ideal option is a foundation thickness of 20-30 cm. This is the optimal parameter for the construction of knowledge, regardless of the materials used and the types of soil at the construction site.

If the project provides additional protection from low temperatures, then the foundation is insulated with foam plastic plates and, accordingly, when making calculations, the thickening of the edge must be taken into account. The frost-resistant type of monolithic base is made of reinforced concrete slab. It is irrational to use a base with a thickness of more than 30 cm.

The thickness of the strip foundation walls must be at least 35cm. If the construction site is dominated by loose soils, it is necessary to expand the base of the foundation by arranging several ledges in order to reduce pressure on the soil. The width of the erected elements should be about 20 cm, the height indicator should be about 30-40 cm. The edge of the strip foundation must exceed the level of the ground surface.

Calculation for a monolithic strip foundation

To begin with, we determine the following dimensions: the width of the walls, the perimeter of the future building and the height of the foundation pouring. Each of these indicators is necessary for the correct calculation of the casting volume.

Let's start with the calculation:

Let's find the height of the foundation. To do this, we use the following formula:

F ≥ Z + 10 cm ., where F is an indicator of the height of the foundation, and Z is a unit of column embedding depth.

Important ! The height of the foundation should be greater than or equal to the length of the reinforcement used to strengthen the concrete pour.

Then we calculate the volume of the casting. To do this, we use the following formula:

V excellent = b × P × F , where b is the width of the walls, P is the perimeter of the base, F is the height of the casting.

V = ( b × l × F ) - V excellent ,where b is the width of the walls, l- foundation length F - casting height, V ex - casting volume.

It is also necessary to calculate the formwork. To do this, the first step is to determine the area of ​​the side surfaces. After this, we find the area of ​​the side walls; to do this, we multiply the perimeter of the base by 2 and multiply by the height of the casting. At the next stage, the area of ​​one board is determined:

S boards = b × l , where b is the width of the board, and l- length of the board.

Amount of lumber = S side surfaces / S one board.

Let's consider the calculation of a monolithic strip foundation using an example. Let us assume that the foundation has the following initial data:

• length -15m;
• width - 3.8m;
• casting height - 0.3 m;
• casting height - 0.18 m.

Based on these data, we determine the volume of the casting using the previously discussed formula. We get that V ex = (15*2+3.8*2)*0.18*0.3 = 2.03m3.

Now let’s determine the volume of the internal part V = (3.8*15*0.3) - 2.03 = 15.07 m3.

As a result of the calculations, we determined that the volume of the casting is 2.03 m3, and the volume for filler is 15.07 m3.

Conclusion

The technological process of arranging a monolithic foundation is very complex and expensive. But it is strictly unacceptable to make any changes to the calculations of materials in order to save money. Otherwise, such activities can lead to very disastrous results. The erected structure will be so fragile and of poor quality that it is unlikely to be able to withstand the load of the building. As a result, complete or partial destruction of the erected structure is possible.

Therefore, calculations of the main parameters of a monolithic foundation must be carried out with strict adherence to all recommendations, and in case of controversial situations, you need to seek help from specialists.

In the next video we will look at typical mistakes when reinforcing and concreting a monolithic strip foundation

In country house construction, a strip base is most often used, which is rightfully considered universal. You can build it without involving specialists yourself. The main thing is to carry out all the calculations correctly, including the required amount of reinforcement for the construction of a strip foundation.

A strip base is a monolithic closed reinforced concrete strip running under each load-bearing wall of a building. This type of foundation is most often used in individual construction, because has a good set of necessary characteristics and excellent price-quality ratio.

It distributes the load along the entire perimeter and prevents subsidence and deformation of the building due to the acting forces of soil heaving. Wherein . Some hobbyists do not consider it necessary to reinforce the foundation. But this process is of great importance.

After all, ultimately the strip base acquires the following properties:

• strength, reliability and durability;
• ease of installation;
• possibility of waterproofing reinforced rods.

Reinforcing steel frame is the strength skeleton of a concrete foundation

Therefore, to increase the service life of the entire building, reinforcement is indispensable. But the main thing is not only to correctly strengthen the foundation, but also to calculate it correctly.

Planning the foundation must be done with particular care, because in case of deformation, it can affect the entire building, and fixing it can be very difficult and expensive. You can calculate the amount of materials required for a strip foundation and rolled steel for it yourself, or you can use the online calculator service.

An example of calculating a strip foundation

To calculate the strip foundation, you need:

• calculate how much the house weighs without taking into account the foundation;
• determine snow and wind loads;
• choose the type of base.
• calculate the area of ​​the foundation base, taking into account the bearing capacity of the soil.

Snow load can be calculated based on SNiP 2.01.07-85. Section 5 provides data for all areas. It is quite difficult to calculate the wind load of a strip foundation. You can use the simplified formula: (15 x h + 40) x S, where h is the height from the ground surface to the top of the building, and S is the area of ​​the structure.

When calculating the weight of a building, it is necessary to take into account the approximate weight of furniture and equipment located in the room. For example, with a building mass of 13384 kg, a payload of 11340 kg, a snow load of 8820 kg, and a wind load of 4410 kg, the calculations will look like this. Summing up these data, we get the figure 37954 kg. You need to add 30% to it for errors. As a result, the total load on the base is 49340 kg.

In order to calculate a strip foundation, it is necessary to take into account its base length and sole area. So, if the length of the load-bearing wall is 30 m (3000 cm), then: 24670/3000 = 8.2 cm. This figure is the minimum width of the strip base. But it is necessary to take into account that the thickness of the walls should be greater than the width of the foundation.

In order to calculate how much concrete is required, it is necessary to multiply the length of the load-bearing wall by the amount by which the foundation must be laid and by the width of the foundation. So, if the foundation on sandy soil is laid to a depth of 0.5 m, the width of the foundation is 20 cm (0.2 m), the length of the load-bearing wall is 30 m, then the calculation will look like this: 30 x 0.5 x 0.2 = 3 m3.

All materials for the foundation must be purchased with a small margin of 10-15%

Reinforcement calculation

Next, you need to calculate how much material will be needed for reinforcing work. For example, the diameter of the steel rod will be 12 mm, according to the plan in the casting there will be 2 horizontal rods, and vertically, for example, the rods will be located in increments of 0.5 m. The perimeter is 27 meters. So, 27 must be multiplied by 2 (horizontal rods) and the result is 54 m.

We count vertical rods in a similar way: 54/2 + 2 = 110 rods (108 intervals of 0.5 m each and two on each side). To account for the rods at the corners, you need to add 1 more rod, it turns out 114. If we take the height of the rod -70 cm, we calculate the length of the material: 114 x 0.7 = 79.8 m.

The easiest way to calculate the reinforcement for a strip foundation is to use an online service - a calculator.

Formwork calculation

If the parameters of the boards are: thickness 2.5 cm, length 6 m and width 20 cm, then the calculation will be as follows. The formula calculates the area of ​​the side surfaces: the perimeter is multiplied by the height of the casting, and then by 2 more (the fact that the internal perimeter is smaller than the external one is not taken into account): (27 x 0.2) x 2 = 10.8 m2. Board area: 6 x 0.2 = 1.2 m2, 10.8/1.2 = 9.

This means that as a result, 9 wooden boards are needed, the length of which will be 6 m. A small number of connection boards is added to this number(at the discretion of the builder). As a result: you will need 134 m of reinforcing materials and 27 linear meters of wooden blocks 20 cm wide. The example did not take into account the number of fasteners. The received data is rounded.

Calculation of reinforcement for a floor slab can also be performed using an online calculator.

Reinforcement scheme

On a strip foundation, more longitudinal tensions appear than transverse ones. Therefore, you can choose rods with a smooth surface as transverse rods, and corrugated ones as longitudinal rods. The corners bear the most loads. Therefore, when reinforcing them, it is necessary that one end of the rod goes into one wall, and the other into the other.

The reinforcement process should begin with the installation of formwork. The inside should be lined with a layer of parchment. The main purpose of the formwork is to facilitate the removal of the structure. The task of the frame is to uniformly distribute all loads on the base.

Its scheme is simple:

• Steel rods equal in length to the depth of the foundation are driven into the bottom of the trench. It is necessary that there is, on average, 50 mm from the formwork in increments of 400-600 mm;
• install stands (80-100 mm);
• 2-3 threads of the bottom row of rods are attached to them. For stands, you can use bricks, placing them on the edges;
• at the top and bottom the rows are secured with transverse jumpers to the vertical pin;
• the places where they intersect are fastened with viscous wire or welding.

When calculating and constructing a strip foundation, it is recommended to take into account the requirements of SNiP so that the structure is strong and durable

Welding work contributes to overheating of the metal and entails a change in properties. The thickness of the rods in such places also decreases. That's why Wire is often used for knitting. After reinforcement, it is only necessary to make holes for ventilation and fill the trenches with concrete mortar.

Cost of fittings

Reinforcement can be purchased at construction stores. Its quantity is calculated in linear meters. Therefore, in order to find out how many meters are required and calculate the final price, necessary rolled weight table. Next, we calculate using the formula: (number of metal rods in running meters) and multiply by (weight of 1 running meter of rods for the corresponding diameter) multiply by (cost of 1 ton of rods)/1000.

The weight of the reinforcement depending on the cross-section can be seen in the table:

Reinforcement with a diameter of 12 mm and a corrugated or smooth surface is in great demand. It can be sold in rods and coils.

The approximate price for 12 mm diameter per 1 m can be found in the table:

Reinforcing a strip base is not at all difficult, although it is a fairly energy-intensive process that requires financial investment. But saving doesn't make sense. By choosing the right reinforcement and calculating its quantity, you can strengthen the foundation, while extending the life of the entire building.

You can watch an example of independent calculation of a strip foundation in the video:

Then the cross-sectional area will be:

40 100 = 4000 cm2.

Determine the total cross-sectional area of ​​the reinforcement (minimum):

4000: 1000 = 4 cm2.

Since the width of the tape is 40 cm, 2 rods need to be placed in one grid, and the total quantity is 4 pieces.

Then the minimum cross-sectional area of ​​one rod will be 1 cm2. Using SNiP tables (or from other sources) we find the closest value. In this case, you can use reinforcing bars with a thickness of 12 mm.

Determine the number of longitudinal rods. Let's say the total length of the tape is 30 m (tape 6: 6 m with one jumper 6 m).

Then the number of working rods with a length of 6 m will be:

(30: 6) 4 = 20 pcs.

Determine the number of vertical rods. Let's say the clamp pitch is 50 cm.

Then, with a tape length of 30 m, you will need:

30: 0.5 = 60 pcs.

Determine the length of one clamp.

To do this, subtract 10 cm from the width and height of the section and add up the results:

(40 - 10) + (100 - 10) = 120 cm. The length of one clamp is 120 2 = 140 cm = 2.4 m.

Total length of vertical reinforcement:

2.4 60 = 144 m. The number of rods with a length of 6 m will be 144: 6 = 24 pcs.

NOTE!

The obtained values ​​should be increased by 10-15% in order to have a margin in case of errors or unexpected material costs.

Types and sizes

There are two main :

• Metal.
• Composite.

The metal bars used to assemble the reinforcement cage have a ribbed or smooth surface.

Ribbed rods are used for horizontal (working) reinforcement, as they have an increased adhesion force to concrete, which is necessary to perform their functions efficiently.

Vertical rods, as a rule, are smooth, since their task is to maintain the working rods in the desired position until pouring. The diameter of the rods ranges from 5.5 to 80 mm. Working rods of 10, 12 and 14 mm and smooth rods of 6-8 mm are used.

Composite reinforcement consists of different elements:

• Glass.
• Carbon.
• Basalt.
• Aramid.
• Polymer additives.

Fiberglass reinforcement is the most widely used.

It has the greatest strength, the most rigid and resistant to tensile loads of all other options.

Like all types of composite rods, fiberglass reinforcement is completely resistant to moisture.

Manufacturers claim constant performance throughout the entire service period, but in practice the validity of this statement has not yet been verified. The problem with composite reinforcement is the complexity of the technology, due to which the quality of the material differs markedly from different manufacturers.

In addition, composite rods are not able to bend, which is inconvenient when assembling frames and reduces the strength of the corner joints of the frame.

IMPORTANT!

Among builders, the attitude towards composite reinforcement is complex. Without denying the positive qualities, they do not put too much trust in little-studied building materials that have not gone through a full cycle of use. In addition, metal reinforcement has very specific technical characteristics, while composite types have a fairly wide range of properties. All these factors limit the use of composite rods.

How to make the right choice

The choice of reinforcing bars is based on design data and builder preferences.

Typically, metal rods are chosen, although composite reinforcement is increasingly used every year in the construction of strip foundations. Preference is given to metal rods due to the ability to give them the necessary bend, which is impossible to do with fiberglass rods.

This is especially important when constructing belts with curved sections or when there are fracture angles other than 90°.

In addition, metal reinforcement is more economical, as it allows you to make clamps from a single rod, without having to create multiple connection points.

The diameters of the rods have long been worked out in practice; they are often chosen without preliminary calculation - for about 30 cm, a 10 mm rod is used, for strips with a width of 40 cm, 12 mm rods are chosen, and for a width of more than 50 cm - 14 mm. The thickness of the vertical reinforcement is determined by the height of the tape; up to 70 cm, 6 mm is chosen, and for heights above 70 cm, 8 mm or more.

Useful video

In this section you can also see how calculations are performed using the example of a real construction site:

Conclusion

A well-chosen reinforcement scheme and the material itself ensure the strength and resistance of the tape to possible loads.

Complex and problematic soils, prone to heaving or seasonal movements, require a responsible and attentive approach to.

It must be taken into account that all calculated values ​​determine the minimum design parameters that require some increase for a certain safety factor.

When choosing reinforcement and reinforcement scheme, you need to multiply all values ​​by 1.2-1.3 (reliability factor) to reduce the risk of unforeseen factors.

In contact with