In this article, you will learn how to calculate the load on the foundation - how to calculate how much the foundation itself and the building (house) will weigh, including various additional mass in the form of snow and wind. The foundation of any capital structure is the foundation. The service life of the building depends on its reliability. That is why laying the foundation is one of the most important stages of all construction. In order for the foundation to withstand the expected loads, it is necessary not only to strictly observe the technology of its construction, but also to make a preliminary calculation of the impact on it. Only a specialist with sufficient experience and knowledge can take into account all the factors affecting the reliability of the foundation. However, anyone can make preliminary calculations. They will show how reliable the foundation will turn out, and will also save a certain amount of money, eliminating the extra costs of building a foundation more than necessary.
Read about calculating concrete for a foundation
Load types
There are three main types of foundation load:
- The first type is static, direct weight of structures and elements of the house.
- The second type means the influence of weather conditions, such as wind, precipitation, and so on.
- The third type includes the pressure created on the supports by various things and objects inside the house.
At first glance, the last two types may not seem so important, but in practice it is necessary to take into account all the little things, only then the foundation will not sag under the influence of pressure. An important feature of any foundation calculation is not only the pressure exerted on it. The factors that determine the size, depth of occurrence, the degree of its reinforcement and the determination of some other technical characteristics of this structural element include such as the properties of the soil and the area of support.
Formula for calculating the load on the foundation
The basic formula used to determine the values is as follows: H = Nf + Nd.
Here:
- Н - the required value (total load on the foundation);
- Нф - foundation load;
- Нд is the total load from the building (load of the house).
The last two parameters of this formula are determined using special tables or other formulas, which we wrote about below.
Calculation of the load of the house on the foundation (Nd)
This value includes the three above-mentioned indicators. The values of the loads of various materials have already been calculated by specialists and are summarized in general tables and reference books, which you can use.
- Frame structures, with a wall and insulation thickness of no more than 150 mm - up to 50 kg / m2;
- Red brick walls up to fifteen centimeters thick - 270 kg / m2;
- Log cabin and solid wood walls - about 100 kg / m2;
- Reinforced concrete walls up to 15 cm thick - 350 kg / m2;
- Overlapping with the use of reinforced concrete structures - up to 500 kg / m2;
- Overlappings using wooden beams and insulation with a density of 200 × 500 kg per cubic meter - from 90 to 300 kg / m2;
- A roof made of various materials can yield from 30 to 50 kg / m2? (roofing from roofing material and slate up to 50 kg / m2, sheet steel up to 30 kg and tiles up to 80 kg.).
Having calculated the area of the building elements, it is not difficult to find the desired value. For the temporary load created by snow, take values from 190 kg / m? for cold northern regions and 50 kg / m? for the southern regions. The wind load can be calculated as follows: HB = P? (40 + 15? N).
Here in the formula:
- Нв - wind load;
- P is the area of the building;
- H is the height of the house.
By summing up all the values obtained, you can easily determine the required pressure value created by the house in tons.
Foundation load (Nf)
To calculate the load created directly by the foundation, you need to use the following formula: Нф = Vф? Q.
Here:
- Vf is the volume of the foundation, obtained by multiplying its total area by the height;
- Q is the density of materials used in construction, this value can be obtained from tables or other reference materials.
For pile foundations, this formula is also valid, with the only difference that the result obtained must be multiplied by the number of piles and add the weight of the belt, if applicable. The weight of the belt can be calculated by multiplying its total volume by the density of the materials used.
The use of piles in the construction of the foundation is one of the highest priority areas. This is due to the fact that they penetrate to a depth much deeper than freezing of the soil, which means they are a more reliable foundation for any building. Video about the advantages of a foundation on screw piles:
Specific values of soil load
This value shows what maximum pressure a certain soil area can withstand without displacement and subsidence. For different types of soil and different climatic zones, the specific pressure may be different, but 2kg / cm? Is taken as the average.
Calculating the total area of the foundation with which it contacts the soil and multiplying it by the average specific pressure, we obtain the maximum possible load on the soil.
At the same time, do not forget about the various units of measurement in the area of the foundation, where square meters are used and the specific value, where they resort to square centimeters. It is necessary to reduce them to common units of measurement. The value obtained is compared with the maximum load obtained using the formulas above. If the maximum allowable unit pressure is less than the load exerted by the structure, then it is necessary to increase the support area. Thanks to these simple calculations, you can determine the size of the foundation and be sure that it will serve as a reliable support for the structure for many years.
