Accurate calculation of the thickness of the foundation slab

The strip foundation is a concrete reinforced base for any structure. It is poured along the required perimeter and can have from one to several tapes on which the supporting walls will be installed . But it is entirely possible that there is only one perimeter. Such a foundation ensures uniform dispersion of a considerable mass of the structure over the surface of the earth. There must be a calculation of the thickness of the foundation slab, since a very thin slab may not withstand the mass of the house.

The main types of foundations

The strip foundation, depending on the material used for laying it, is of three main types:

• stone, which includes subtypes such as brick, rubble and semi-rubble;
• reinforced concrete, subdivided in turn into molten and precast;
• wooden.
  

The calculation of the thickness of the foundation slab of each of these types is carried out individually, and its algorithm cannot be applied equally in all cases.

Basic subtypes of foundations

The following subtypes of foundations are distinguished.

1. Cement and soil. Designed for lightweight structures, usually non-residential. Ideal for gazebos and small warehouse cabins. Its installation is possible only on a solid and level platform.
2. Sandy. Also designed for buildings with low weight. It can be used for panel sheds and small country houses. For residential buildings can not be used.
3. Mixed type. Brick tape with rubble or concrete base - this is the type of foundation. A plate whose thickness calculation is precisely calibrated is already more durable. It is possible to use this type of foundation for the construction of summer cottages.
4. Brick. Installation of such a foundation is carried out only on hard and dry soil. Excess moisture can lead to the destruction of the brick base and violate the integrity of the building. Clay iron is used for this type of foundation. Usually it is red.
5. Butovy. Ideal for installation on heaving soils. Usually laid at shallow depths. The rubble stone has a natural origin and great strength.
6. Concrete. Installation of this type of foundation is carried out by laying stones of small diameter, which are then poured with a solution of concrete. Before starting installation, formwork is required. The concrete foundation is also similar to the monolithic type. The difference is only in the use of large aggregate, that is, stones.
7. Monolithic. Installation is carried out in the presence of formwork. Reinforcement is installed on the required area, which is then concreted using a special solution. It turns out quite a solid foundation. A monolithic slab, the calculation of the thickness and depth of which are important points when pouring this type of support, is stable if everything is done correctly.
8. Reinforced concrete precast. It is similar in structure to a monolithic foundation. The only difference is that the precast concrete foundation is produced at the plant, then it is only exported to the construction site. This type of foundation, in turn, is divided into two subtypes: pillow blocks, which are stacked at the very first level of the foundation, and FBS blocks, which are installed on top of pillow blocks in two or three rows.

Special application of reinforced concrete precast foundation

The construction of a reinforced concrete precast type of foundation is possible only with the use of a construction crane, since FBS blocks and pillow blocks are very heavy and an ordinary person will not be able to lift them. It is usually used for the construction of large buildings with significant weight and implying a solid foundation. The plate, the calculation of the thickness of which requires great accuracy, should be made only of high-quality material.

Four foundation designs

All subtypes of foundations are divided into four main types, which differ in their design and the materials used.

1. Pile. A universal type of construction, but very difficult to install. It is used on various types of soil, as well as with large differences in elevation of the terrain, where it is impossible to apply the foundations of other structures.
2. Columnar. It is located pointwise around the perimeter of the load-bearing walls. Its use is recommended only on a stable site of soil, the difference of which is a maximum of 5 degrees.
3. Plate, or solid. It is a slab whose function is to disperse the bulk of the structure onto the foundation. A monolithic plate, the calculation of the thickness of which must be very accurate, determines the main bearing load, namely, it increases the pressure on strong sections, removing weight from weaker ones.
4. Monolithic. It has the appearance of a continuous filling tape. Depth of occurrence is divided into shallow and deep, which depends on the level of total freezing of the soil and the main drop in the area.

Calculation of the thickness of the foundation under the house

The calculation of the thickness of the foundation slab under the house should be made based on data on the freezing of soil on the site. You should not listen to the advice of loved ones and especially neighbors that they are so filling the foundation and that the house is normally standing. It will not lead to anything good. Although the sites can be very close, the soil on each of them will be different. Have you ever wondered why the neighbors have small potatoes, and you have large ones, even though you watered and fertilized it the same way? This is simple evidence of the presence of different soil in nearby areas.

Calculation formula

The calculation of the thickness of the foundation slab depending on the load is made according to the following formula: S> γn · F / (γc · R0), where γc is the value of the main operating conditions; γn - usually equals 1.2 - reliability value; F - total weight on the base, concluded in the sum of the mass of the house, foundation and other loads; R0 is the soil resistance under the perimeter of the foundation; S is the area of ​​the perimeter of the foundation, usually measured in square centimeters. It must be remembered that for the construction of even the smallest and lightest home, it is necessary to calculate the thickness of the foundation slab.

Site Preparation Tips

There are some basic tips for preparing for installation of the foundation. If they are fulfilled, the support for the house will last a long time and will not require major reconstruction.

1. Firstly, before starting installation, it is necessary to get rid of the upper vegetative soil layer. With this, you will be able to level the site for the construction of the house and remove the general slope of the terrain, if any.
2. Secondly, it is necessary to provide an uninterrupted drainage system. Usually, for this purpose, trenches with a depth of about 50-70 centimeters are excavated around the entire site. Such a measure will avoid stagnation of water and, therefore, premature destruction of the foundation from moisture.
3. Thirdly, on a flat area make the installation of the pit. It is important to remember that any type of foundation is installed on a dense sand cushion.
4. Then make accurate calculations of the thickness of the foundation slab. This will save you from the need to purchase excess materials and money.
   

Conclusion

Choosing the right type of foundation will depend on the type of soil and its slope. The use, for example, of a monolithic type in marshy terrain will be a stupid step, since the foundation can sag and fall apart from the water. Calculation of the thickness of the foundation slab, perhaps, can be considered one of the most important points in its construction. The second such moment is the high quality of building materials used for installation. It’s better not to save on them.