The foundation is called underground part buildings or structures that receive loads and transmit them to the ground. The most popular type of foundation for building houses is considered to be a strip foundation. Such a common application strip foundation due to its versatility and affordable cost. Before you begin construction, you need to make a choice between a shallow and buried strip foundation.
Shallow strip foundation
A shallow foundation saves both budget and time. And labor costs will be significantly less, since its construction does not require a deep pit. This type of foundation is used for lightweight structures small area:
- wooden houses
- aerated concrete structures or buildings constructed from aerated concrete and foam concrete blocks, the height of which does not exceed 2 floors
- monolithic buildings with permanent formwork
- small structures built of stone
The depth of the shallow foundation reaches half a meter.
Recessed strip foundation
Such a foundation is used to build structures with heavy walls, concrete floors, basement or underground garage. The length of the foundation depth must be calculated in advance. First, you need to determine the level of soil freezing, then subtract 30 cm and lay the foundation at this depth.
Preparing for work
To build a strip foundation yourself, you must first carry out precise planning. The need for careful calculations is explained by the fact that the foundation is one of the most important structural elements of any building or home. Mistakes made at the beginning of construction can provoke negative consequences during the operation of the house.
Marking
Marking is carried out by marking on the ground both the external and internal boundaries of the future foundation. For this, it is best to use pegs or reinforcement rods and ropes. But it will be more effective to use special devices such as laser levels. Remember that large errors in markings will significantly affect appearance finished construction.
To achieve ideal results you need:
- determine the axis of the structure being built
- use a plumb line to mark an angle, then pull a rope from it at an angle of 90 degrees to two more corners of the structure
- use a square to determine another angle
- check the angles, focusing on the diagonals. If the test gives positive results, pull a rope between them
- take on the internal markings, retreating from the external markings to the distance of the thickness of the future foundation
When you are finished with the markings, study the differences in the surface at the construction site and select the lowest point to measure the depth of the trench and eliminate the difference in the height of the foundation. If the building is planned to be small, then the depth of the pit can be 40 cm.
Cushion installation and waterproofing of strip foundation
A sand cushion with added gravel should be laid on the finished trench. The recommended height of each layer is 120-150 mm. After this, each layer must be shed with water and compacted to increase density. To isolate ready-made pillow, you need to lay a durable waterproofing film on it.
Installation of strip foundation formwork
The formwork is usually made of planed boards approximately 40-50 mm thick. You can use slate for this purpose.
When erecting formwork, control verticality. The recommended height of the frame above the ground is 30 cm. This is necessary to build a small base. Asbestos concrete pipes are laid in the formwork to introduce sewerage and water supply into the building.
Place between concrete and formwork plastic film, this will protect the formwork from contamination.
Laying reinforcement
The next stage is the installation of fittings. Reinforcing bars with a cross-section of 10-12 mm are connected with a special knitting wire so that the sides of the square cells are 30-40 cm. The reinforcement can be either steel or fiberglass.
Ventilation and communications
Pouring a strip foundation with concrete
Fill the formwork with concrete gradually. The thickness of the layers is 15-20 cm; to avoid voids and increase overall strength, compact the layers with a special tool - a wooden tamper or an internal vibrator.
You can order ready-made concrete mixture from the factory or make it yourself using a concrete mixer. The recommended proportion of cement, sand and crushed stone is: 1:3:5.
The layers should not differ in composition. In cold weather, you should use a concrete heater and frost-resistant additives; in hot weather, water the concrete.
Completion of work
Once the concrete is poured, it should be covered with film to prevent drying out and left to gain strength for at least 2 weeks.
Construction begins with a project. It is recommended to first sketch even small structures on paper so that you can clearly see the proportions and estimate the consumption of materials. For serious buildings, you need design and estimate documentation made by professionals, but when constructing a private house, cottage, fence or garage, you can get by online calculators or ready-made solutions. The most important issue in the construction of structures is the construction of a reliable foundation, and therefore the question of how to calculate the amount of concrete for the foundation is paramount.
It is not difficult to calculate concrete for the foundation if you are certain about the size and type of structure. The type of foundation and its dimensions should be determined by an experienced builder, based on the characteristics of the building under construction, the type of soil and the depth of its freezing in the area.
Tape
The most popular foundation for the construction of a private house is considered to be a strip foundation. It is a kind of closed ribbon of concrete running under all the load-bearing walls of the building.
How to calculate how many cubes of concrete are needed for the foundation? Calculators to help determine consumption cement-sand mortar for pouring, are available on many construction-related sites, one of which is presented at the end of this material. To calculate the volume in cubic meters, you need to know the linear dimensions of the structure: height, width and total length of the base.
Concreting strip base occurs by pouring the finished cement-sand mixture into wooden formwork with pre-installed reinforcement mesh. Large fractions (gravel, crushed stone) are added to the solution to obtain higher strength characteristics of the foundation.
The dimensions of the base depend on the dimensions of the building that is planned to be erected. Typically, the width of the foundation strip is at least 300 mm, the height of the ground part is from 400 mm, and the depth can reach 1500-2500 mm depending on availability groundwater, depth of freezing and the desire to equip a basement. It is not recommended to install strip foundations on heaving soils if the formwork is buried below the freezing depth.
For middle zone, when constructing small private houses and baths, it is enough to deepen them within 1500 mm with a height of the ground part of up to 400 mm.
The length of the foundation will be equal to the total length of all external walls, including the internal one load-bearing wall, under which the base is also installed. As a result, having received all the required values, you can calculate the volume of concrete for the foundation. Calculator in in this case may not be necessary - just multiply all the indicators in meters and get the desired number in cubic meters.
The calculation formula looks like this:
V=h*b*l, Where:
- V – volume of solution in m3;
- h – height in m;
- b – width in m;
- l – tape length in m.
For example, for a building measuring 6x6 m and one internal load-bearing wall, with a foundation height of 2 m and a width of 0.4 m, the volume of mortar for pouring will be: V=2*0.4*30=24 m 3. With the same width and height of the foundation, for a house measuring 10x10 and two load-bearing internal walls, the calculation will look like this: V=2*0.4*60=48 m 3.
This calculation allows you to calculate the almost exact cubic capacity of the solution, but it should be remembered that during transportation some of the concrete is lost, and also if the formwork is loose, some concrete mortar may leak, but there is additional internal volume occupied by the reinforcement cage. Therefore, it would be correct to introduce a correction factor in the direction of increasing the calculated value by 2%.
As a result, we obtain a more accurate formula for calculating the volume of concrete for a strip foundation:
V=h*b*l + 0.02*(h*b*l)
The resulting value is rounded to the nearest whole number. For our examples, the refined calculation will look like this: for a 6x6 house V=24+0.02*24=24.48 (25) m 3, for house 10x10 V=48+0.02*48=48.96 (49) m 3.
Slab
A slab foundation is a continuous monolithic foundation under a building site. For its construction, concrete of a grade not lower than M100 is used. Calculating the volume of this monolith is quite simple - just multiply the length, width and height of the slab.
Pouring a solution of cement and sand with the addition of large fractions for monolithic slab produced to a height of at least 100 mm. Thus, for a slab with a thickness of 100 mm, the following volumes of concrete are obtained:
- for a house 10x8 – 8 m3;
- for a 9x9 house – 8.1 m3;
- for a house 18x8 - 14.4 m3.
This calculation is suitable for completely flat slabs, but to give the base higher strength characteristics, additional trapezoidal stiffeners are often installed longitudinal beams. Therefore, the correct calculation of a slab foundation must also include the volume of pouring stiffeners.
To the already obtained volume of the slab, it is necessary to add the volume of the stiffeners, for which the formula for the area of a trapezoid is used. Volume slab foundation with stiffeners are found as follows:
- Calculate the volume of your slab: V=h*b*l.
- Find the area of the trapezoid: S=h1*(a+c)/2, where h1 is the height of the edge of the trapezoid, and and c are the lengths of the bases of the trapezoid.
- Find the volume of the stiffener and multiply by the number of ribs: V1=S*l*n, where n is the number of stiffeners.
- The resulting volumes are added up and the total volume of concrete required is obtained: Vtotal=V+V1.
Typically, reinforcement is located at the bottom of the base in increments of 3000 mm. They can be made as exclusively longitudinal reinforcements, or with intersections, forming squares. Typically, the ratio of the wide part of the trapezoid of the stiffener is 1.5:1. To calculate a slab foundation, volume adjustments are also provided with an error factor of 2%.
Columnar
This type of foundation is a kind of pile field, only support pillars are not driven by a pile driver, but are poured into prepared pits. A columnar foundation allows you to get a reliable foundation when minimum consumption material. The pillars may have round or square section, they are placed along the perimeter of the building spot and at the junctions of the walls.
Deepening columnar foundation usually exceeds the freezing depth for a given area, and the ground part has a height of 400-500 mm. The building structure can be installed directly on the support pillars, but most often a grillage is installed around the perimeter, which connects the pillars into a single whole.
To calculate the volume of concrete required for pouring a columnar foundation, you need to know the length of the column, its cross-sectional area and the number of columns. If a grillage is provided, its linear dimensions will be required; the volume of the grillage is calculated in the same way as in the case of a strip foundation.
V=a*b*l*n, where a and b are the cross-sectional sides of the pillar, l is the length of the pillar, n is the number of pillars in the foundation.
To calculate the volume of concrete for pouring pillars with round, you will need a formula for finding the area of a circle: S=3.14*R*R, where R is the radius. We get the formula for calculating the volume of pillars with a circular cross-section:
To obtain the total volume of concrete required for pouring the pillars and grillage, it is necessary to add up the already obtained indicators, not forgetting the error factor of 2%.
Calculation of cement for the foundation.
Any house is built strictly according to the project, which is developed by specialists. One of the most important points in construction planning is the calculation of the foundation. But some of the buildings have to be built independently. These include bathhouses, garages, gazebos and even small residential buildings. In such cases, it is important to select and design high-quality and reliable foundation. Moreover, the cost of the foundation from all work sometimes reaches 1/3. If you make a mistake, it is sometimes not possible to redo the foundation of the house, and it is always expensive. And no one will return the spent energy and time. You can learn how to calculate the foundation for a house and choose the right one from this article.
The foundation of a house is primarily the basis for the structure, the quality of which will determine how long the building will last. Any construction of a house made of timber must be built in accordance with the approved documentation, in which the calculation of the foundation is not the least important.
A properly designed foundation will protect the building from flooding and will save the construction of a house made of laminated veneer lumber or any other from cracking and destruction. The platform must be designed to easily support the weight of the house and at the same time distribute the load evenly onto the ground.
The foundation calculation includes:
- Calculation of loads for various types of soil.
- Calculation of cubic capacity (determining how much building materials necessary).
- Calculation of the cost of the foundation, including labor and materials.
The most common mistakes when installing the base can be seen in the video:
Which base design to choose?
In construction wooden houses I use constructions:
- Tiled.
- Tape.
- Columnar.
- Pile.
There are areas where it is rational to use a mixed type platform, for example, a strip-pile platform. This is a modification of one of the main types. But this complex design and builders are trying to change the composition of the soil to one of the main types. This is how the swampy area is drained and sand washed in, or part of the soil is simply removed and covered with slag, which, when compacted, turns into concrete.
The foundation is chosen depending on the house being built. The heavier the structure, the more massive the foundation. To build a house from profiled timber or rounded logs, strip or columnar types are used. Moreover, the tape type is made shallowly recessed.
The depth of occurrence is calculated based on two main factors:
- Depth of groundwater.
- Soil freezing in the area of future construction.
There are average standards for the depth of the sole on various soils:
- Sandy loam - 125cm
- Clay and loams - 150 cm
- Sand and gravel - 100 cm
This is the maximum occurrence of the foundation of the house according to construction GOST, but it also indicates the maximum occurrence rates:
- For dry soil - 70 cm,
- For wet areas with close groundwater - 120 cm.
If the house according to plan has basements, then the sole of the structure should be at least 40 cm below the floor level.
Each type of foundation has its pros and cons. So, for example, a columnar one is erected behind short time, tape is considered one of the most durable due to the rigid connection of the structure both across and along. Monolithic is expensive, it is built in rare cases when the soil is very mobile.
What loads affect the foundation?
There are always two forces acting on the base:
With proper calculation, the foundation must withstand the weight of the house, furniture, residents, snow and wind, as well as pressure from swelling of the soil. When planning, the weight of a building is calculated in accordance with special tables that indicate the approximate weight of a particular material. It’s not difficult to calculate how much a house costs using these tables. The weight of the house should be 1 cm 2 /kg greater than the load that the soil can withstand. So for some types of soil this load is equal to:
- Gravel and coarse sandstone - 3.5-4.5 kg/cm2.
- Fine sandstone - 2-3 kg/cm 2
- Clay hard soil - 3-6 kg/cm2.
- Crushed stone - 5-6 kg/cm2.
When making calculations, one should not forget that the base structure itself also has a certain weight. In any case, design calculations are always individual for different areas and buildings.
All loads on the foundation are divided into permanent (roof, walls, floor beams, waterproofing, etc.) and temporary ( snow cover, wind, etc.).
The total load (the house itself, the foundation, the insulation system) and during operation (furniture, people living, etc.) are calculated.
After construction, the house shrinks, and so does the foundation. The soil underneath is compacted and the foundation “sags” - this value is called settlement. If the settlement is uneven, the foundation will quickly crack and fall apart. To avoid this, you need to accurately calculate the area of the foundation and calculate the load on it.
How is the load on the foundation calculated?
Having determined the size of the house, it is not difficult to calculate the area of the foundation for it. This is done for correct calculation loads. The load depends on what material the house is assembled from. The regulatory construction documentation shows the specific gravity of the foundation depending on various materials:
- Brick and concrete - 1880-2200 kg/m 3,
- Household stone - 1600-1800 kg/m 3,
- Weight of the walls of a wooden house:
- Frame - panel - 30-50 kg/m2,
- Lumber, rounded and chopped logs - 70-100 kg/m2.
To determine the load, it is important to know the weight of the floors:
- Basement floors - 100-300 kg/m2,
- Attic floors - 150-300 kg/m2,
- Reinforced concrete floors - 500 kg/m2.
Roof specific gravity:
- Sheet steel - 20-20 kg/m 2
- Ruberoid - 30-50 kg/m2
- Slate - 40-50 kg/m2
- Ceramic tiles - 60-80 kg/m2.
Let's see how we can use these indicators using a real example:
According to the plan, the future house measures 8x5 with one interior wall. The height of the building is 3 m. In order to find out the length of the walls: 5+8+5=18 m. We calculate the area of the walls: 18x3=54 m2.
To calculate the area of the basement floors, let’s create the product of the length and width of the house: 5x8=40 m2. Attic floors They have the same area as the basement ones, which means also 40 m2.
The next step is to calculate the weight and area of the foundation
Foundation area and weight
Calculating the foundation is not difficult, let’s look at a specific example:
For the construction of the house, a strip foundation with a base of 1.5 m was chosen, to this figure you need to add 50 cm above the ground level. The height of the foundation will be exactly 1.50 + 0.50 = 2 m. Then the length is calculated: (5 + 8) x 2 = 26 m. Internal partition has a length of 5 m. 26+5=31 m.
Let's calculate the volume of the foundation by multiplying the length and height and width. Let's take a width of 50 cm, 0.5 x 31 x 2 = 31 m 2. Now, according to the above data, let's calculate the weight of the foundation: Reinforced concrete weighs 2400 kg/m3, 31x2400 = 74,400 tons. The supporting area of the foundation will be 31,000x50 = 15,500 cm 2.
To determine the total weight of the structure, you need to add the weight of the house with the weight of the foundation and divide it by the resulting supporting area. So we get a weight of 1 kg/cm 2.
If the permissible area for a certain type of soil is higher, then you need to change the width of the platform for a strip one, and the number of pillars for a columnar one. But at the same time, the total weight of the structure will increase, so the calculations need to start again.
How to calculate concrete for a foundation
In order not to purchase unnecessary building materials, it is important to accurately calculate the cubic capacity of the foundation. To calculate the cubic capacity, it is important to take into account two factors: the type of foundation and the complexity of its design. For the convenience of readers, consider the calculation various types foundation separately.
Calculation of the cubic capacity of the strip base
It is easiest to calculate the cubic capacity of a strip foundation. To do this, you need to add the length, width and height. Let the width be 50 cm, we have already calculated the height above 1.5 m. The length is calculated along the perimeter 5+ (8 + 5) x 2 = 45 m. The cubic capacity is calculated: 0.5 x 45 x 1.5 = 33.75 m 3. We round this data and add 10% (margin), we get 37 cubic meters of concrete.
Calculation of cubic capacity of a columnar base
A columnar foundation may have different shape(circle, square, etc.). Let's calculate the cubic capacity for example round pillars. For this you need the following values: diameter, cross-section, column height. The area is calculated by multiplying Pi by the radius x 2. Cross section for a pillar with a radius of 15 cm: 3.14x0.075m = 0.2355 m. Knowing the radius and height, you can calculate the volume: 0.2355x1.5 = 0.353 m3. This number must be multiplied by the number of pillars in the foundation.
Calculation of cubic capacity for a slab base
To calculate a monolithic rectangular slab, you need to know its area and thickness. The planned house has dimensions of 5 x 8, therefore the area of the slab will be 40 m2. Experts recommend using a monolith 10-15 cm thick. We calculate the cubic capacity at 10 cm thickness: 40x10 = 400 m 3.
On monolithic foundation Stiffening ribs are made around the perimeter. To calculate their area, you need to know their length and width. In a 5x8 structure, I install stiffeners every 2.5 m. There will be 3 such ribs in width and 4 in length. The total length will be equal: (5x3) + (8x4) = 47 m.
Now let's calculate the cubic capacity. The width of the rib is equal to the thickness of the slab - 10 cm. This means that the area of one rib is exactly 0.1 x 0.1 = 0.01 m2. We multiply the area by the length 47 = 0.47 m 3.
How to determine the amount of reinforcement and wire
To create a rigid and durable structure in installation, use iron fittings. Its quantity depends on the type of foundation, loads and soil. Reinforcement with a larger diameter is used to obtain a platform with a greater load capacity. But the weight of the foundation with reinforcement increases. If the soil is hard, then the foundation will deform minimally, which means that the reinforcement will need a minimum diameter.
Quantity of reinforcement for strip base
The reinforcement for a strip foundation is taken with a diameter of 10-12 mm, since the structure itself can withstand heavy loads. They lay it in two rods, regardless of how deep the base is. Experts recommend laying the reinforcement 10-15 cm from the top pouring point. Vertical rods do not have a load, so the cheapest ones can be used.
For a house measuring 5x8, the length of the strip base is 45 m. With reinforcement of 4 rods, the consumption will be: 45x4 = 180 m. We add transverses with a foundation height of 150 cm and a width of 50 cm in increments of 40 cm: (8/0.4)x0.5 =10 m. Add them to the length: 180+10=190 m.
Knitting wire is needed for one connection 30 cm. Length 45 m and pitch 40 cm: 45/0.4 - 112.5. We multiply this figure by the size of one connection: 112.5 x 0.3 = 33.7 m of binding wire needed for a 1-level foundation.
Quantity of reinforcement for columnar base
To reinforce the columnar base, thick reinforcement from 40 mm is used. Horizontally, the reinforcement does not bear any load, so here you can take the most inexpensive one. On average, 4 rods are used in the frame of one pillar. Knowing the number of pillars, it will not be difficult to calculate the size of the reinforcement.
For a structure 1.5 m high with a diameter of 15 cm, you need 4 rods, with a pitch of 7.5 cm and binders at 3 points. Thick reinforcement needed: 1.5x4=6m. For a thin bundle: 30 cm (for one node) x 3 = 90 cm. If 20 pillars are used in the foundation, then the number is multiplied by this figure.
Knitting wire is needed to connect one rod at 3 points. This number is multiplied by the number of rods and vertical connections: 3x4x30=72 m.
Number of reinforcement for a monolithic base
For dense, stable soil, you can take thin reinforcement from 10 mm. For heavy structures and unstable soil from 14 mm. The ligament is attached in increments of 20 -30 cm.
For a 5x8 platform you need 27 pieces in length and 17 pieces in width. Since a double harness is needed: (17+27)x2=88. This number must be multiplied by the length of the rod to obtain the footage of the reinforcement.
How to calculate the cost of a foundation
After the calculations of the cubes and the amount of reinforcement have been made, it is easy to calculate the cost of the foundation. Work and the price of formwork boards are added to the basic cost + earthworks and technology.
On average, the cost of a turnkey structure starts from 15,000 m2. But you can save money and do all the work yourself.
The cost of ready-made concrete mortar ranges from 700 rubles per cubic meter, but you can reduce costs by making concrete yourself. To do this you will need sand, gravel and cement M250 or 400. The average price for cement is from 800 rubles. per bag of 40 kg. KamAZ sand costs from 2,500 rubles, it is enough to fill the foundation.
Costs are also reduced when performing partial work, for example, digging a trench and making formwork with your own hands, and entrusting the pouring of concrete to specialists.
In any case, you should not skimp on the foundation of the house, as it must be reliable and durable. And we explained in detail how to calculate and not overpay.
Calculating the load on the foundation from the future house, along with determining the properties of the soil at the building site, are two primary tasks that must be performed when designing any foundation.
An approximate assessment of the characteristics of load-bearing soils on our own was discussed in the article. And here is a calculator with which you can determine the total weight of the house being built. The obtained result is used to calculate the parameters of the selected type of foundation. A description of the structure and operation of the calculator is given directly below.
Working with the calculator
Step 1: We mark the shape of the house box we have. There are two options: either the box of the house has the shape of a simple rectangle (square), or any other shape of a complex polygon (the house has more than four corners, there are protrusions, bay windows, etc.).
When choosing the first option, you need to specify the length (A-B) and width (1-2) of the house, while the values of the perimeter of the external walls and the area of the house in plan required for further calculations are calculated automatically.
When choosing the second option, the perimeter and area must be calculated independently (on a piece of paper), because the options for the shape of the house box are very diverse and everyone has their own. The resulting numbers are entered into the calculator. Pay attention to the units of measurement. Calculations are carried out in meters, in square meters and kilograms.
Step 2: We indicate the parameters of the basement of the house. In simple words, the base is the lower part of the walls of the house, rising above the ground level. It can be executed in several versions:
- the base is the upper part of the strip foundation protruding above the ground level.
- the base is a separate part of the house, the material of which differs from both the foundation material and the wall material, for example, a foundation made of monolithic concrete, the walls are made of timber, and the base is made of brick.
- the base is made of the same material as the outer walls, but since it is often lined with other materials than the walls and does not have interior decoration, so we count it separately.
In any case, measure the height of the plinth from the ground level to the level on which the plinth rests.
Step 3: We indicate the parameters of the external walls of the house. Their height is measured from the top of the plinth to the roof or to the base of the pediment, as indicated in the figure.
The total area of the gables as well as the area of windows and doorways in external walls you need to calculate based on the project yourself and enter the obtained values into the calculator.
The calculation includes the average specific gravity figures window designs With double-glazed window(35 kg/m²) and doors (15 kg/m²).
Step 4: We indicate the parameters of partitions in the house. In the calculator, carriers and non-carriers load-bearing partitions are considered separately. This was done on purpose, since in most cases the load-bearing partitions are more massive (they take the load from the floors or roof). Non-load-bearing partitions are simply enclosing structures and can be built, for example, simply from plasterboard.
Step 5: Specify roof parameters. First of all, we select its shape and, based on it, set required sizes. For typical roofs The areas of the slopes and their angles of inclination are calculated automatically. If your roof has a complex configuration, then the area of its slopes and their angle of inclination, necessary for further calculations, will have to be determined again independently on a piece of paper.
Weight roofing in the calculator it is calculated taking into account weight rafter system, taken equal to 25 kg/m².
The calculation in the calculator is made based on formula (10.1) from SP 20.13330.2011 (Updated version of SNiP 2.01.07-85*):
S 0 = 1.4 ∗ 0.7 ∗ c e ∗ c t ∗ μ ∗ S g ,
where 1.4 is the reliability coefficient for snow load adopted according to paragraph (10.12);
0.7 - reduction factor depending on the average temperature in January for a given region. This coefficient is taken equal to one when the average January temperature is above -5º C. But since almost throughout the entire territory of our country the average January temperatures are below this mark (visible on map 5 of Appendix G of this SNiP), then in the calculator the change in the coefficient is 0.7 by 1 not provided.
c e and c t - coefficient taking into account snow drift and thermal coefficient. Their values are taken equal to unity to facilitate calculations.
S g - the weight of the snow cover per 1 m² of the horizontal projection of the roof, determined based on the snow area we selected on the map;
μ is a coefficient whose value depends on the angle of inclination of the roof slopes. At an angle of more than 60º μ =0 (i.e. the snow load is not taken into account at all). At an angle less than 30º μ =1. At intermediate values of the angle of inclination of the slopes, it is necessary to perform interpolation. The calculator does this based on a simple formula:
μ = 2 - α/30, where α is the angle of inclination of the slopes in degrees
Step 6: Specify the parameters of the floors. In addition to the weight of the structures themselves, the calculation includes an operating load equal to 195 kg/m² for the basement and interfloor ceilings and 90 kg/m² for attic floors.
Having entered all the initial data, click the “CALCULATE!” button. Whenever you change any of the initial values, also click this button to update the results.
Note! Wind load is not taken into account when collecting foundation loads in low-rise construction. You can look at paragraph (10.14) SNiP 2.01.07-85* “Loads and impacts”.
