Calculation of the strip foundation

Examples of how to calculate this type of important construction object are intended for those who independently build housing or start construction for the first time. Using formulas and data, they get a calculation for a solid, sound tape foundation and lay the durability of the entire structure.

Calculation of the basement. On-line calculator

In online mode, the user has the right to make a complex mathematical calculation of the future monolith under the tape foundation. On the pages display monotonous tables. Having learned to use at least one of them, it is easy to calculate for any others. This method allows you to perform an accurate calculation for different types of foundation, formwork, calculate the parameters of the reinforcement, the consumption of concrete mix.

1. Decoding of calculation points:

• name The total length of the tape. It involves data on the perimeter of the foundation. Substituting should be real numbers, which are taken after the object's measurement;
• name The area of ​​the band soles. Determination of the reference area of ​​the future basis. Must match the dimensions of the selected waterproofing system or material;
• name Area of ​​a part of the lateral surface of the outer. It is assumed equal to the area of ​​the insulation for the outside;
• name Volume of a concrete solution. This is the amount of concrete required to build a foundation for specific characteristics. It is determined only when the concrete solution is produced independently. The quantity of the ordered solution will be different from the actual figure due to the compaction of the solution during the pouring process. The result is increased for the stock by 10%;
• name Weight of concrete solution. Calculated by the average density of cement-concrete mortar;
• name Load on the ground produced by the calculated foundation. Shows the amount of load distribution per total area;
• name The smallest longitudinal diameter of a reinforcing bar. It is selected from SNiPs, where all accepted diameters are indicated, taking into account the concentration of reinforcement along the section of the area of ​​the strip foundation;
• name The smallest number of rows of reinforcement in the lower and upper belts. Supposed number of rows of longitudinal rods in one belt of the ribbon. It is determined from the reduction of the actual deformation of the tape from compression or stretching during operation;
• name The minimum diameter of the clamps. After calculation, the closest SNiP value is selected;

• name Step clamps. The figure necessary to reduce the shear of the framework of the reinforcement when the concrete solution is flooded;
• name The value of the overlap of the reinforcement. It is calculated for the overlapping attachment of rods or a rod;
• name Full, total length of reinforcement. The value of the total length of the reinforcement when the carcass overlaps;
• name Total weight of reinforcement. The weight of the entire reinforcing skeleton;
• name The thickness of the formwork boards. It is chosen according to the characteristics of the foundation, the accepted step of support from the table of SNiP according to GOST P 52086-2003;
• name Number of boards for the formwork equipment. It is calculated in meters of running or in edging material in meters.

A real example of calculation of a strip foundation of heaving soils:

We accept the data: monoblock concrete, installed on gravel from granite. For better understanding, draw up a plan yourself.

Belt foundations, the external area of ​​which has a slope, is better opposed to irradiation, swelling, destruction from frost. Therefore, an object with such features was adopted for calculation.

1. Data for calculation:

• foundation, tape, size 6x3 m;
• at the top 0.2 m;
• down, sole 0.25 m.

2. Performance characteristics of a dwelling for a calculated strip foundation:

• walls from a gas block with a thickness of 400 mm;
• floor of the lower floor. Bulk on granite gravel and soil;
• high-grade two-storey house;
• floors between floors. Iron-concrete slabs, factory;
• roof. The ramp is 45 degrees. Logs are wooden, covered with tiles;
• primer. Plastic clay;
• the location of the new building. The hilly plain.

The maximum load on the foundation strip is made on its side, with 6 m sections, because of the pressure of the slabs, the roof lag.

The total load on the foundation is calculated by the sum of all the loads: from snow, from the roof, from the ceilings, from the walls of the house, from the foundation material.

3. Calculation of the snow load:

• select the value of SNiPa, the load for a specific location. Multiply the figure with the cargo area of ​​the roof per 1 m of the basement;
• calculates the roof area, the arithmetic method is simply the total amount of the roof area. The resulting figure is divided by the length of the lateral bases of the ribbon foundation( 6.0 + 6.0 = 12.0 m).Not accepted in calculating the size of the ends;
• roof area: calculated by multiplying the length of the ramp by the length of the cornice and doubling the product;
• the length of the ramp: Dsk = 3/2 = 1.5 / cos 45 = 2, 145 m;
• total roof area Scr: 2x2.145 = 4.29x 6 = 25.74 m2;
• cargo area per 1 m of foundation tape: 25.74 / 12 = 2.145 m2;
• we choose from the standards a moderate zone, for example the 2nd, the value of snow specific load = 700 N / m2;
• value of snow load: 2.145х70 = 1500 N.

4. Determination of roof load:

• is determined by the load of one square meter of the roof projection in the horizontal;
• according to our data is a 1.5 m tiled gable roof, located at a 45 degree slope;
• coefficient is selected from the corresponding table SNiP = 800 N / m2.1.5 x 80 = 1200 N.

5. Determination of the load from overlaps:

• coefficients are selected from the corresponding tables of SNiP;
• cargo floor area = 6x3 = 18/12 = 1.5 m2.12 is the length of the sides;
• load from the wooden floor of the attic from the table = 300 kg / m3;
• load from reinforced concrete floors = 500 kg / m3;
• total load from overlappings: 1.5 x( 300 + 500) = 12000 N.

6. Load per 1 m of the basement from the external walls:

• is the product of the wall load m2 per height and the wall thickness above the foundation;
• according to the SNIP table selects the load of one square meter of the wall area;
• for our calculation, the height of the aerated concrete wall is 3 m. The thickness is 40 cm;
• total: 3 x 0.4 x 600 = 7200 N.

7. Calculation of the load from the gas-base foundation:

• load value = volume of a meter section of the foundation multiplied by the value of the material density;
• the density of the material is selected from the corresponding SNiP table;
• for the 2nd zone( taken in the calculation of the snow load), on the heaving ground when laying the foundation deep into 1 meter, you can take the volume of 0.450 m3;
• coefficient for concrete and crushed stone = 2300 kg / m3;
• total value: 0.450 x 2300.0 = 10350 N.

8. Calculation of total load per foot length meter:

• total load: 150.15 + 120 + 1200 + 720 + 1035 = 42250 N;
• to compare the calculated value with the recommended value for plastic clay = 15 N / cm2.The area of ​​the calculated foundation is 50 x 100 cm = 5000.0 cm2.4225, 15/5000 = 9 N / cm2.To build a foundation of aerated concrete for a given locality according to the accepted parameters is possible.

To transfer Newtons to the value - kilograms of force, adopted in the ICGSS measurement system, the calculated values ​​should be divided by 10.

The usual pile-and-tape foundation. Calculation of self-construction

Feature of the purpose of the pile-tape foundation poured on unstable ground. The optimal material for its production is a ready-mixed mortar of the M300 brand, or even better, the M350.This material is intended for wet, floating, heaving soils. It has proved to be well in operation in areas that are unfavorable in terms of humidity.

1. Calculation of concrete for a strip foundation:

• first calculates the volume of concrete for the foundation tape. Simple arithmetic multiplication of the length, width and depth of the tape is performed;
• further calculates the volume of concrete for the pile. By the formula: V = PI x r2 x h. Decoding Pi is the standard value accepted 3.14 r is the radius of the pile rod, h is the height of the pile rod or the height of the pile itself;
• is now a practical work. Take a building meter and measure the actual values ​​of your building material;
• substitute the values ​​for the corresponding place in the formula, calculate the volume of one pile unit;
• multiplies the unit volume by the number of piles purchased or the estimated number of products in the future design;
• but after learning the total volume of the tape, the total volume of the concrete mix under the piles, calculate the tonnage of the concrete solution.

2. Simplified method for calculating the volume of a concrete mortar for piles:

• , a standard pier manufacturing size with a diameter of 200 mm is adopted;
• is simpler, a pile with a length of 1000 mm, a diameter of 200 mm will require only 0.125 m3 of concrete solution;
• this number is multiplied with the actual length of the pile;
• after calculating the volume of concrete solution, do not relax. Make a metal frame, preferably from the A3 armature.

Calculation of shallow basement foundation for beginning builders

The main purpose of a finely laid foundation is to withstand the construction of a small structure on more or less stable soil, without kata seasonal troubles.

The main stages of the calculation:

• defines the characteristics of soil hydrogeology on the construction site;
• necessarily reveals the possibility of the occurrence of groundwater under the site, their location to the surface, seasonal floating, ravages and other;
• for accurate determination, the real host will spare no money for calling a specialist and compiling a hydrogeology of the area;
• shallow foundation shall be laid on sandy or uniform ground;
• determine the local composition and properties of the soil;
• calculate the parameters, as for any ribbon foundation, if desired, using the methods described above. Do not be lazy and calculate according to the general principle. It is more complex, but also more reliable;
• determine the weight of all the structural elements required in the calculation formula;
• make correction of dimensions and parameters of a possible design from the obtained data from arithmetic calculations.

Calculation of the tape solid foundation

The simplest of the types of tapeworm basement. All you need is to define a few specific values:

• b - Wall width, h - bay height, p - perimeter of the building;
• the volume of the casting of the concrete solution is calculated: H> / Z + 10 cm. Clearly, H is the fundamental height, Z is the deep room of the column;
• the obtained value is compared with the anchoring length. Deepening to accept more or equivalent anchoring;
• defines the volumetric outflow parameter: b - walls multiplied by the total p( perimeter) of the room / structure, h - the casting height;
• volume of internal tide: the usual formula for determining the volume of the school course: l - length, b - width, h - height, multiply;
• calculate the formwork. Have found a side surface area( a hint for those who forgot) multiply the doubled perimeter with the height of the low tide. Calculate the area of ​​the unit of the plank table: the width, multiplied with the length;
• units of boards: divide the sum of the lateral surface areas by the unit area of ​​the product.

Simplified calculation of reinforcement for the strip foundation

Having decided and drawing a sketch of the reinforcement, proceed to the calculation of: volume and quantity. Incorrect definition will force you twice to pay for delivery, suspend construction, and also spoil your working mood.

1. For an example, we represent the calculation on the figures:

• the given perimeter of the house( 6+ 7) х 2 = 24 units.amend. The overall perimeter of the house;
• 25 + 6 = 31 units.amend.- total length of the basement;
• 31 х 4 = 124 units.amend.- total length of reinforcement.

If the rod is not of the same size as calculated or required, in the case of planning to join the cuttings, pieces in one piece, take a stock of wire material from 1 meter. The connection must be made lapped, not saving on the strength of the house.

• assume that the rods have only 1 connection. So, according to the scheme, we need 4 reinforcement bars, multiply by the number of walls in house 5 and get 20 connections. What does it mean, an additional 20 meters to the calculated one;
• total footage for armaturin - 124 + 20 = 144 meters.

2. Example calculation for rods with a surface smoothness of 8.0 mm diameter that will go to vertical racks, horizontal crosspieces-jumpers:

• length between elements = 50.0 cm;
• 31 / 0.5 = 62. Received the number of units of reinforcing rings;
• grating, for example, also with a height of 50.0 cm and a distance of 25 cm, then the calculation is:( 50.0 + 25.0) x 2 = 150.0 is the perimeter of the reinforcing ring;
• then the total length is multiplied by 1.5: 62 x 1.5 = 93.The result is the value of the entire length of the rods;
• requires you to consider the factor of trimming, re-overlapping, marriage. Professionals recommend increasing the arithmetic figure by 10% to get a real value.