How to calculate reinforcement for a strip foundation - practical tips and rules

Belt foundation is the most common for self-erecting various buildings. However, the pouring into the formwork of a concrete solution alone is not done. To strengthen the foundation in the overwhelming number of cases, it is reinforced, which greatly enhances the structure and increases its bearing capacity.

In practice, for the arrangement of such a "wire" frame is used a metal rod( you can use the latest composite reinforcement).It can be smooth or ribbed, have a different diameter. But in the process of preparing for the work, it is necessary to calculate its required quantity. After all, if it turns out to be much larger, then where do you put the surplus? And if not enough, it's a delay, a simple, a waste of time.

What to consider when calculating

1. Any metal is susceptible to corrosion. Consequently, the reliability of the structure in which it was used, when it is in direct contact with water, drastically decreases. During the installation, as well as during further operation, concrete partially begins to crumble. Plus, in it with varying degrees of intensity( depending on the brand, the presence or absence of various additives, the quality of waterproofing) gradually absorbed moisture. To protect against the reinforcement, the frame is mounted in such a way that all its parts( rods) are spaced from the surface of the pouring by approximately 50 mm. And from either side - from the sides, from above, from below.
2. The load on the vertical( and transverse) parts of the carcass( rods) is lower than the longitudinal ones. Therefore, to save, you can use products with a smaller diameter. Usually for a monolithic monolith of a private structure take a rod of 10 or 12 mm( for longitudinal laying) and 6 or 8 mm - for vertical and transverse.
3. If the tape has a different width( for example, around the perimeter and inside the structure, under the load-bearing partitions), then the calculation is made separately for each part.
4. The joining of the longitudinal elements is done with mutual overlapping - approximately 50 cm. Consequently, the length of each subsequent rod is "reduced" by this amount.
5. When pouring concrete, the frame "expands" under the weight of the solution, especially if a filler with coarse fractions is used. Therefore, to strengthen the structure, in addition to the same rod, staples( in the form of the letter "P") are placed along the entire perimeter, which "tighten" the side walls of the "lattice".
6. The number of rows horizontally and vertically depends on the parameters of the tape - its width and the depth of the bookmark( height).In order not to deal with computations by formulas( and they are on some sites), in which not everyone will understand, use tentative data. For small private buildings this is quite enough.

The distance between the bars in the horizontal plane is chosen so that between them there is not more than 25 - 30 cm. As a rule, they are stacked on 4 pieces in a row. Between vertical elements( and transverse) - from 30 to 60 cm along the entire tape.

How to calculate

It makes no sense to give specific figures, since all foundations have different sizes. Therefore, we give only the algorithm itself, choosing arbitrary data. Substitute their true values ​​for a specific construction of labor does not.

• The length of the tape is measured. L. It will be laid in one row, for example, 4 bars along it. Let's assume that these rows, in accordance with the depth of the fill, will be 3. Consequently, the total length of the rod is L x 4 x 3.
• The number of joints of longitudinal elements 24. We know that each of them "reduces" the bar by the length of the overlap. Consequently, it turns out: 50 cm x 24 = 120 cm = 12 m.
• Stitches, transverse and vertical rods must be laid along the entire length.
• The total length of the material is:

( L x 4 x 3) + 12 m +( the length of the cross-bars multiplied by their number) +( length of vertical bars x per number) +( staple length x per number).

But this is if the entire structure is assembled from a material of the same section. In the case of the use of bars of different diameters, counting is carried out for each of them separately. The entire reinforcement process is described in detail in this article.

In the presence of internal bearing walls for their foundation, calculations are carried out using the same procedure.

Several tips

• The ribbed rod( unlike the smooth one) more reliably "mates" with the concrete solution.
• It is necessary to choose bars of such length that when they are laid in longitudinal direction, there are as few joints as possible.
• Connections on the corners of the tape are not allowed. Only - the bending of the bars.
• The material for the reinforcement needs to be taken a little more than the required, as the bar sections can be used for other purposes. For example, to install mortgages when facing aerocrete walls with brick masonry. There are many options, so you need to take into account all the nuances of construction, so as not to go for purchases on several occasions.