Any building, regardless of its purpose, is unthinkable without a reliable basis. The construction of the foundation is one of the most important and natural tasks of the entire construction cycle as a whole, and this stage, by the way, is often one of the most time-consuming and costly - often before a third of the estimate takes exactly on him. But at the same time, any simplifications should be absolutely excluded here, unreasonable savings on the quality and quantity of necessary materials, neglect the current rules and technological recommendations.
The whole variety of foundation designs is maximum popular as the most versatile, suitable for most of the houses erected in the field of private construction and economic structures. Such a base is highly reliable, but, of course, with its high-quality execution. A key condition of strength and durability is competently planned and proper reinforcement. belt Fundament The drawings and the basic principles of the device of which will be issues of consideration in this publication.
In the article, in addition to the schemes, there will be several calculators that will help the novice builder in performing this sufficiently difficult task of creating a ribbon foundation.
Important features of the belt foundation
General concepts. Benefits of tape foundation
So, briefly, several general concepts about the device of a belt foundation. By itself, it represents a solid concrete strip, without breaks for door or carrier processes, which become the basis for the construction of all external walls and capital internal partitions. The tape itself is plunged into a certain estimated distance in the soil and at the same time protrudes on top of its basement. The width of the tape and the depth of its embezzlement, as a rule, is withstanding one on all over the foundation. Such a form contributes to the most uniform distribution of all loads falling on the base.
Ribbon foundations can also be divided into several varieties. So, they are not only poured from concrete, but also make prefabs, applying for this, for example, special foundation reinforced concrete blocks, or using butt content. However, since our article is devoted to reinforcement, in the future only the monolithic version of the foundation belt will be considered.
Ribbon foundation can be attributed to a universal base type. Such a scheme is usually given preference in the following cases:
- When erecting houses from heavy materials - stone, brick, reinforced concrete, building blocks, and those like. In short, when it is necessary to evenly distribute a very significant load on the ground.
- When the developer plans to get a full-fledged basement or even the ground floor - only the ribbon scheme can afford it.
- In the construction of multi-level buildings, using heavy inter-storey overlaps.
- When a plot for development is characterized by the heterogeneity of the upper layers of the soil. An exception is only completely non-stable soils when creating a ribbon foundation becomes impossible or unprofitable, and it makes sense to refer to another scheme. It is impossible to ribbon foundation and in regions with permafrost.
The monolithic belt foundation has a considerable amount of other advantages to which the durability, assessed by many dozen years, the relative simplicity and understandability of the construction, ample opportunity in terms of laying engineering communications and the organization of warmed first floor floors. According to its strength qualities, it is not inferior to monolithic plates, and even surpasses them, demanding less material tools.
However, one should not think that the belt foundation is absolutely not a vulnerable design. All listed advantages will be valid only if the parameters of the foundation for the house will correspond to the conditions of the construction district, the estimated load, have a stated strength reserve. And this, in turn, means that special requirements are always presented to the design of the foundation (any, by the way). And the ribbon reinforcement in the series of these problems occupies one of the key positions.
Tape width of the foundation and depth of it
These are two key parameters from which the scheme of the reinforcement of the future foundation belt itself will depend on.
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armature
But the degree of rehabilitation into the ground ribbon foundations can be divided into two main categories:
- A low-profiled belt foundation is suitable for the construction of frame structures, small country houses and household buildings, provided that there is enough stable, dense soil on the site. The ribbon sole is located above the boundaries of the fruit of the soil, that is usually not lowered below 500 mm without taking into account the base unit.
- For buildings, built from heavy materials, as well as in areas where the condition of the soil does not differ in stability, a deep downstream tape is required. Its sole is already falling below the level of ground freezing, at least 300 ÷ 400 mm, and in the presence of construction plans also (basement) is even lower.
It is clear that the height of the foundation tape as a whole, including the depth of its location, is not arbitrary values, but the parameters that are obtained as a result of carefully carried out calculations. During the design, a whole array of source data is taken into account: the type of soils on the plot, the degree of their stability both in the surface layers and the change in the structure as depicted; climatic features of the region; Availability, location and other features of soil aquifers; Seismic characteristics of the area. Plus, the specificity of the building planned for the construction of the building is superimposed - the total load, as static, created only in the construction of the structure (naturally, taking into account all its components) and dynamic, caused by operational loads, and all sorts of external influences, including wind, Snow and others.
Based on the above, it will be appropriate to make one important remark. The principal position of the author of these lines is that the calculation of the basic parameters of the foundation tape is not tolerate the amateur approach.
Despite the fact that on the Internet, a lot of online applications can be found for such calculations, the question of the design of the foundation still will correctly entrust to those skilled in the art. At the same time, the correctness of the proposed calculation programs is not at all challenged - many of them fully comply with the SNiP acts and are able to really give accurate results. The problem lies in a slightly different plane.
The bottom line is that any, even the most advanced calculation program, requires accurate source data. But in this matter, it is impossible to do without special training. Agree to correctly assess the geological features of the site for construction, take into account all the loads falling onto the foundation tape, and - with the decomposition of them along the axes, to provide all possible dynamic changes - non-professional simply unable. But each initial parameter matters, and the underestimation may well be then "to play the evil joke."
True, if it is planned to build a small country house or an economic building, then the invitation of the designer can seem to the excessive measure. Well, at your own fear and risk of the owner can build a low-profiled belt foundation using, for example, by the approximate parameters that are shown in the table below. For light buildings, a strongly blurred tape is not required (a great blowing can also play a negative role, due to the application of tangential forces during frosty sweeping of the soil). As a rule, in such cases, the maximum depth of the arrangement of the sole in 500 mm is limited.
| Type of built building | Shed, Bath, Household Buildings, Small Garage | One-story cottage house, including - with an attic | One- or two-storey cottage designed for permanent accommodation | Two or three-storey mansion |
|---|---|---|---|---|
| The average value of the load on the soil, KN / m² | 20 | 30 | 50 | 70 |
| Types of soils | Recommended depth | Staging a ribbon | (Excluding the basement | Part of the foundation) |
| Pronounced rocky soil, oooka | 200 | 300 | 500 | 650 |
| Dense clay, loam, without falling after compression effort palm | 300 | 350 | 600 | 850 |
| Floored dry sand, soup | 400 | 600 | Communicably professional calculation of the foundation | |
| Soft sand, or saturated soil or sand | 450 | 650 | Communicably professional calculation of the foundation | Communicably professional calculation of the foundation |
| Very soft sand, or soil or sand | 650 | 850 | Communicably professional calculation of the foundation | Communicably professional calculation of the foundation |
| Peatman | Other type of foundation is required | Other type of foundation is required | Other type of foundation is required |
Once again we emphasize - it is only averaged values \u200b\u200bthat cannot be considered as the truth in the last instance. In any case, if the amateur builder uses similar sources, it takes a certain risk to its responsibility.
Now - about the width of the foundation tape.
It also has its own features. First, to ensure the rigidity of the foundation design, it is customary to adhere to the rule that the overall height of the tape should at least twice the width of its width - but this rule is observed. And the second - the width of the ribbon in the sole region should be such that the distributed load is less than the calculated soil resistance parameters, naturally, also with a certain constructive reserve. In a word, the foundation tape with full load should be stably, not searched to the ground. In order to save materials, it is often necessary to increase the sole of the ribbon foundation with broadening.
Probably, it makes no sense to bring the formulas and table values \u200b\u200bof soil resistance to conduct independent computing. The reason is the same: not so much the difficulty in performing calculations, how many problems with the correct definition of the initial parameters. That is, again, it is better to turn to professionals on such issues.
Well, if a lightweight building or a country house is built, then it can be guided by the fact that the width of the tape should be at least 100 mm more than the thickness of the walls. As a rule, with independent planning of the foundation, they take round values, multiple 100 mm, usually ranging from 300 mm and higher.
Reinforcement of the foundation ribbon
If a specialist is engaged in the design of the belt foundation, then the finished drawing will certainly include not only the linear parameters of the most concrete belt, but also the characteristics of the reinforcement - the diameter of reinforcement rods, their number and spatial location. But in the case when a decision is made on the independent erection of the founding under the building, when planning a design, it is necessary to take into account certain rules established by the SNiP.
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What valves will suit these goals?
For proper planning, it is necessary to at least understand a little in the armature sorting.
There are several criteria for the classification of reinforcement. These include:
- Production technology. Thus, the valve is wire (cold-rolled) and a rod (hot-rolled).
- By the type of surface, reinforcement rods differ in smooth and having a periodic profile (ripping). The profile surface of the reinforcement provides maximum contact with the fused
- The valve can be intended for conventional or pre-strained reinforced concrete structures.
To create a reinforcing construct of a belt foundation, as a rule, apply fittings produced in accordance with GOST 5781. This standard includes hot-rolled products intended for reinforcing conventional and pre-dressed structures.
In turn, this fittings are distributed by classes, from A-i to A-VI. The difference mainly consists in varieties used for steel and, therefore, in the physico-mechanical properties of products. If in fittings primary classes A low-carbon steel is used, then in high classes products, metal parameters are approaching alloyed steels.
All characteristics of the classes of fittings know when independent construction is optional. And the most important indicators that will affect the creation of the reinforcement frame are shown in the table. The first column shows the classes of reinforcement for two standards for the designation. Thus, in brackets, the designation of classes was made, the digital designation of which shows the yield strength used to produce steel reinforcements - when purchasing material in the price list, such indicators may also be.
| Armature class according to GOST 5781 | steel grade | Diameters of rods, mm | The allowable bend angle in cold condition and the minimum radius of curvature during bending (D - the diameter of the rod, D - the diameter of the mandget for bending) |
|---|---|---|---|
| A-I (A240) | ST3KP, ST3SP, ST3PS | 6 ÷ 40. | 180º; D \u003d D. |
| A-II (A300) | T5P, ST5PS | 10 ÷ 40. | 180º; D \u003d 3D |
| -"- | 18G2S | 40 ÷ 80. | 180º; D \u003d 3D |
| AC-II (AC300) | 10GT | 10 ÷ 32. | 180º; D \u003d D. |
| A-III (A400) | 35GS, 25G2S | 6 ÷ 40. | 90º; D \u003d 3D |
| -"- | 32G2RS | 6 ÷ 22. | 90º; D \u003d 3D |
| A-IV (A600) | 80s | 10 ÷ 18. | 45º; D \u003d 5d. |
| -"- | 20Hg2c, 20HG2T | 10 ÷ 32. | 45º; D \u003d 5d. |
| A-V (A800) | 23x2g2t, 23x2g2c | 10 ÷ 32. | 45º; D \u003d 5d. |
| A-VI (A1000) | 22x2g2a, 20x2g2cs, 22x2g2p | 10 ÷ 22. | 45º; D \u003d 5d. |
Pay attention to the last column, which indicates the permissible bending angles and the diameters of the curvature. This is important from the point of view that when creating a reinforcing design, come to produce bent elements - clamps, inserts, legs, etc. In the manufacture of conductors, mandrels or other devices for bending, it is necessary to focus on these values, since the reduction in the bend radius or the angle will lead to the loss of the reinforcement of its strength qualities.
Prut class A-I Produced in a smooth design. All other classes (for some exceptions, which, however, are more dependent on the individual requirements of the customer) - with a periodic profile.
The calculation of the foundation is the responsible stage of preparation for construction. It is necessary to perform it in order to understand what sizes of the section are needed, how much does the reinforcement and what diameter are. Before correctly calculating the support part of the building, it will take to collect baseline data. It is from their accuracy that the literacy of the calculations will depend.
What should be done
Most often, with private construction, a ribbon foundation is used. This type allows you to make a basement in the house, but in some cases it can be economically unprofitable. To make a estimate for work (or approximately estimate how many investments are required), it is necessary to calculate the valve for a belt foundation, also calculate the volume of concrete and its geometric dimensions.
Most often in private construction laid a ribbon foundation
The calculation technique involves the calculation of three quantities. The calculation of the ribbon foundation as a result should give such design information:
- the depth of the bedding;
- the width of the base;
- width overhead.
The calculation of the foundation for the house of bricks or other materials is necessarily starting from determining the depth of the embedding. It depends on the bunch of soil, the level of groundwater and climate. If it is incorrect to calculate this characteristic, the building can be collapsed under the action of frosty powder forces. The tape will simultaneously be exposed to moisture and cold, which will lead to uneven deformations and cracks.
The width of the base should be sufficient to evenly convey the mass of the building on the ground. The smaller the strength of the soil, the wider the sole will be required. Due to the large area, it is possible to distribute the load from the belt foundation for the house on the basis so that each of its plot accounts for no more permissible value.
The foundation must be laid below the level of the primer of the soil The width of the tape is usually taken constructively. It should be slightly more outdoor walls. At the same time take into account the method of manufacturing the tape. For a monolithic foundation there can be a fairly section width of 200-300 mm, while the national team recommended to do at least 400-600 mm. Also, this indicator depends on the depth of the investment. What it is more, the stronger the overturning effects will be (more powerful basement walls will be required).
Preparatory work
Before calculating the foundation for the house, the designer needs to find out the geological data of the site. For large buildings, special geological surveys perform. In private construction, it is permissible to conduct research on your own. In this case, all characteristics are assigned to a visual inspection.
- spanning shuffle, which are deep pits with dimensions in terms of 1x2 m (on average);
- drilling wells manual brown.
In the first case, the type of soil is watching the walls of the shurt. In the second - check the soil on the shores of the bora.
For the study of the soil, inspection of the shurt walls Studies are carried out at a depth, which 50 cm exceeds the estimated tape sharing (which was prescribed only by the marking mark). When conducting work, you need to find out the following characteristics:
- type of soil in the level of the sole;
- the location of the groundwater level (AGB);
- the presence on the lenses of weak soil.
To accurately understand the cov, it will be necessary to conduct a study at several points. At least one of these points should be in the lowlands of the site. Work in drought does not give exact resultSince moisture can go deep into the ground.
It is best to figure out in the spring. In this case, the foundation of the tape will not even be afraid of the flood.
Lens of weak soil is difficult to find. To do this, you need to do shurtes or wells very often. In most situations there is no need. If there is such a nuisance during construction, it is covered with rubble, gravel or sandy-gravel mixture.
If the UGB is deeply in the area, then you can use a deep downstream tape (more than 1.5 m). At the same time, water should be located 50 cm below the sole of the building. At the location of the corve at a distance of less than 1.5 m from the surface, it is reasonable to choose a small breed structure. But this type has limitations. If the moisture is above, it is worth considering another option of the foundation: plate or pile.
The choice of foundation on Blind depends on the corning To calculate the foundation of the foundation, the soil strength will need to know. Characteristic signs Each type of soil can be found in GOST 25100-2011. Special attention should be paid to the applications to this document. The carrier's ability of each type is taken from the table below.
| Type of foundation | Maximum bearing capacity in kg / cm2 |
|---|---|
| Pebble with clay admixture | 4,50 |
| Gravine | 4,00 |
| Sand of a large fraction | 6,00 |
| Sand of the middle fraction | 5,00 |
| Sand shallow fraction | 4,00 |
| Sand dusty fraction | 2,00 |
| Suglink or Susha | 3,50 |
| Clayey | 6,00 |
| Celebratory | 1,50 |
| Bulk with seal | 1,50 |
| Bulk without compaction | 1,50 |
Types that have strength 2 and less kg / cm2 are not recommended to be used as a base. Before construction, it will be necessary to perform their replacement on the sand medium or large.
Determination of the depth of the investment
- AGB (sole must be at least 50 cm above);
- the basement floor mark (sole is located at least 20-30 cm below);
- the freezing mark (the sole must be at least 30 cm below).
The drainage depth is calculated by formulas from regulatory documents. To simplify the task may be needed ready tables. They provide values \u200b\u200bfor large settlements.
To determine the depth of freezing, the easiest way to use the finished table Calculation of loads
Before calculating the foundation for the house, you will need to calculate the load. It is more convenient to collect loads on the foundation in tabular form. All loading are divided into two types: permanent and temporary. The latter are temporary conditionally because includes furniture, equipment, etc. Permanent consist of a mass of building structures.
Calculation of the load on the foundation can be performed completely independently taking into account exact features used materials. But it will be enough to use the table below. It shows the average values, but the load on the foundation will change noncritically.
| Design | Load magnitude, kg / m2 | Reliability coefficient |
|---|---|---|
| Brick wall 510 mm | 920 | 1,3 |
| Brick wall 640 mm | 1150 | |
| Drain wall 150 mm | 120 | 1,1 |
| Crucial wall 200 mm | 160 | |
| Wall on a wooden frame with insulation 150 mm | 30-50 | |
| Gypsum County Partitions 80 mm | 30 | |
| Overlapping from PC plates with cement screed | 625 | 1,2 |
| Wood overlap with insulation | 150 | 1,1 |
| Foundation from reinforced concrete in kg / m3 (!) | 2500 | 1,2 - for the national team 1.3 - for monolithic |
| Roof taking into account the type of coating | ||
| Metal | 60 | 1,05 |
| Ceramics | 120 | 1,2 |
| Bituminous materials | 70 | 1,1 |
| Temporary loads | ||
| From people and furniture | 150 | 1,2 |
| Snow cover | On the joint venture "load and exposure" tab. 10.1 Taking into account the location of the construction site | 1,4 |
The load on the foundation of each type to correctly calculate the cross section, multiply on the reliability factor.
Calculation of the soles on the bearing capacity
The ribbon foundation, the calculation of which needs to be performed, requires the use of only one formula. To choose the size of the belt foundation, they say so:
B \u003d p / (L * R),
Here the letter B means the width of the foundations you want to find. P is the mass of the whole building, taking into account the underground part, which is helping to find the counted charge of loads. R is the strength of the base from the first table of the article. L is a common perimeter of the ribbon design. To correctly calculate the foundation, it is necessary to include both the outer and the inner walls of the basement.
Example of calculation
Calculations include the following steps:
- selection of geometric parameters;
- calculation of concrete for the foundation;
- and the calculation of the reinforcement of a belt foundation.
An example of calculating geometry
To calculate the foundation, we take a two-storey brick house with an outer wall of 510 mm, the total height of the outer wall is 4.5 m. There are no internal walls. It is located in Moskva, the ground on the site is the range of sand (R \u003d 5 kg / cm2). Overlapping (2 pcs., Above the basement and over the first floor) from the PC plates, the septum plasterboard height 2.7 m and a total length of 20 m. The height of the floor is 3 m, the size in the plan - 6x6 m. Water on the site lies low, so It was decided to build a blunt foundation with a height of 2 m. The roof is a four-tie coated with a metal coating. The slope slope is 30 °.
An example of the calculation begins with the collection of loads in the form of a table.
| Type of loading | Calculations |
|---|---|
| The foundation is monolithic (pre-width of 0.6 m around the perimeter of the building, equal to 36 m) | 36m * 0,6m * 2m * 2500kg / m3 * 1,3 \u003d 140400 kg |
| Wall of bricks | 6m * 4.5m * 4pcs * 920 kg / m2 * 1,3 \u003d 129168 kg |
| Plasterboard partitions | 20m * 2.7 m * 30kg / m2 * 1,1 \u003d 1782 kg |
| Overlapping | 2pcs * 6m * 6m * 625 kg / m2 * 1,2 \u003d 54000 kg |
| Roof | 6m * 6m * 60kg / m2 * 1,05 \u003d 2268 kg 2268 kg / cos30 ° \u003d 2607 kg |
| Useful | 2 overlaps * 36m2 * 150kg / m2 * 1,2 \u003d 12960 kg |
| Snow | 36m2 * 180kg / m2 * 1,4 \u003d 9072 kg |
| Sum | 349 989 kg |
B \u003d p / (L * R) \u003d 349989kg / (36000cm * 5kg / cm2) \u003d 1.94m. The design is designed.
The calculated width size is round up to 2 m. For width over the entire height, this is a lot, it is enough to be 50 cm under the wall 51 cm. Sve 2 cm is allowed (maximum is 4 cm in one direction). The width of the sole is greater than that which is used in the calculation, but at the highest size is less than the initial one. For this reason, there is no need to redo the calculations with a new mass of underground design.
Counting concrete
Before buying a mixture, its necessary cube should be calculated. To do this, it will be necessary to simply find the volume of the tape. To the amount of concrete for the ribbon foundation, it is recommended to add a stock of 5-7%.
Reinforcement
Armature for a belt foundation is needed to compensate for bending effects. What fittings are used correct for reinforcement? It all depends on the height of the underground part and its length. To understand which fittings are needed as a worker, make simple calculations. The calculation of the number of reinforcement is carried out so that its total cross-section is 0.1% of the cross section of the concrete structure. At the same time there are minimum design requirements:
- What valves are needed for construction from a length of less than 3 m? The answer will be a section of 10 mm.
- At the length of the side, more than 3 m will require 12 millimeter fittings for the foundation.
Foundation reinforcement compensates bending effects The calculation is performed approximately. Calculate the reinforcement will be more accurate only a professional. The step of working rods is selected so that they are distributed evenly. It is advisable to use the same step by placing elements at the bottom of the tape, upstairs and in the middle.
The following is required to calculate the amount for the clamps. They connect the working part of the frame to each other. The layout of reinforcement in the ribbon foundation assumes the presence of vertical and horizontal clamps. They are made of 8 mm diameter rods. The step is prescribed within 20-30 cm. In the corners, the step is reduced twice.
Calculation of the number of reinforcement for a ribbon foundation helps save time and money. Knowing the exact number of reinforcement for each diameter and its step can be easily enhancing the ribbon and purchase materials.
The calculation of the fittings for the foundation is an important stage of its design, so it must be carried out with regard to the requirements of SNiP 52-01-2003 on the choice of the class of fittings, section and its required quantity.
For a start, it should be understood for which metal fittings need metal fittings in a monolithic concrete basis. Concrete after a set of industrial strength is characterized by high compressive strength, and significantly lower tensile strength. The non-reinforced concrete base in the intake of the soil is prone to cracking, which can lead to the deformation of the walls and even the destruction of the entire building.
Calculation of reinforcement for slab foundation
Example of calculation
The house of aerated concrete blocks is mounted on a slab base 40 cm thick on medium-perumenious sublinks. Overall dimensions of the house - 9x6 meters.
Calculation of reinforcement for a belt foundation
In the main load on the gap accounts for along the tape, that is, direituum is directed. Therefore, for longitudinal reinforcement, a rod with a thickness of 12-16 mm is chosen depending on the type of soil and the material of the walls, and for transverse and vertical links, it is allowed to take a rod of smaller diameter - from 6 to 10 mm. In general, the calculation principle is similar to the calculation of the plating fondament reinforcement, but the pitch of the reinforcement grid is selected 10-15 cm, since the efforts to break the ribbon foundation can be significantly larger.
Example of calculation
Ribbon foundation wooden house, The width of the foundation is 0.4 m, the height is 1 meter. Dimensions of house 6x12 meters. Soil - bubbly sandy.
- For the execution of the belt foundation, two reinforcement grids are configured. The lower reinforcement grid warns the rupture of the foundation with soil diplots, the top - when it is bent.
- The grid step is selected 20 cm. For the device of the foundation tape, 0.4 / 0.2 \u003d 2 longitudinal rods in each layer of fittings are required.
- The diameter of the longitudinal rod for a wooden house - 12 mm. To perform a two-layer reinforcement of two long sides of the foundation, 2 · 12 · 2 · 2 \u003d 96 meters of the rod.
- For short sides 2 · 6 · 2 · 2 \u003d 48 meters.
- For transverse links, we select the rod with a diameter of 10 mm. Stacking step - 0.5 m.
- Calculate the perimeter of the ribbon foundation: (6 + 12) · 2 \u003d 36 meters. The resulting perimeter divide on the installation step: 36 / 0.5 \u003d 72 transverse rods. Their length is equal to the width of the foundation, therefore, the total number is 72 · 0.4 \u003d 28.2 m.
- For vertical connections, we also use the bar D10. The height of the vertical reinforcement is equal to the height of the foundation - 1 m. The amount is determined by the number of intersections, multiplying the number of transverse rods by the number of longitudinal: 72 · 4 \u003d 288 pieces. With a length of 1 m, the total length will be 288 m.
- Thus, to perform the reinforcement of the belt foundation will be needed:
- 144 meters of rod class A-III D12;
- 316.2 meters rod class A-I D10.
- According to GOST 2590 we find it a lot. Penon meter rod D16 weighs 0.888 kg; The meter of the rod D6 - 0.617 kg. Calculate the total weight: 144 · 0.88 \u003d 126.72 kg; 316.2 · 0.617 \u003d 193.51 kg.
Calculation of knitting wire: the number of compounds can be calculated by the number of vertical fittings, multiplying it on 2 - 288 · 2 \u003d 576 compounds. Wire consumption per connection take 0.4 meters. Wire consumption will be 576 · 0.4 \u003d 230.4 meters. The mass of 1 meter of wire with a diameter d \u003d 1.0 mm is 6.12 g. For mating fittings of the foundation, 230.4 · 6,12 \u003d 1410 g \u003d 1.4 kg of wire will be required.
The foundation is the most vulnerable part of the design. Due to the fact that the upper part of the building is exposed to the load on the compression, and the lower - on the stretching, the correct base laying plays a big role. To fulfill the correct reinforcement of the ribbon foundation, it is necessary to calculate according to the scheme.
Such a basis is essentially a reinforced concrete strip passing through the outer part of the building and under the bearing walls inside.
In compressions, concrete structures can withstand 50 times more than when stretching. And the upper, and the lower part of the design experiences overload, so it is necessary to perform reinforcement of both parts. On the middle part nothing almost does not have loads. Metal fittings helps solve these problems.
To ensure strength, reliability, durability of the building, any reason must be reinforced. After all, the foundation is subjected to various loads. This is the weight of the whole house, and various soil movements. The ribbon foundation reinforcement scheme resembles a design skeleton, which is assembled from steel rods. In order to choose the necessary scheme for it, it is necessary to understand what it represents.
Reinforcement of the ribbon foundation can be easily done with their own hands, not attracting specialists. It is primarily important to choose the necessary diameter of the reinforcement
Reinforcing material
The choice of material is a fairly important stage. For the reinforcement of the ribbon foundation, with their own hands apply steel rods of different sections or fiberglass fittings. But most often used metal.
The main horizontal fittings has a cross section of rods from 12 to 24 mm. Rods that will be located vertically, which are auxiliary. therefore usually, the cross section of vertical rods from 4 to 12 mm. Such a big difference is due to the scatter in the load on the base and is directly dependent on the type of soil and the weight of the structure.
Auxiliary vertical rods are installed if the foundation height exceeds 15 cm. At the same time, the reinforcement is used by a cross section of 6-8 mm class A1. The frame is collected from rods and clamps, cleaning them from rust. If necessary, the rods straighten and cut. A knitting wire and hook are used as a junction of rods. Welding work can be performed if the "C" marking on the rods.
The choice of diameter affects the number of horizontal levels and the reinforcement scheme of the belt basement.
Calculation of the reinforcement of the belt foundation
The number of reinforcement elements must be calculated based on the size of the base. For foundations, the width of which is 40 cm. Such 4 longitudinal rods are two top and bottom. To install a row of a frame in a ribbon base, 6x6 m in size will be needed, on average, 24 m reinforcement. If you put 4 bar, you will need 96 m longitudinal rods.
For the across and vertical reinforcement of the foundation, the width of which is 0.3 m and the height of 1.9 m for each attachment with an indentation 5 cm from the surface according to the concrete calculator it is necessary (30-5-5) x2 + (190-5-5) x2 \u003d 400 cm or 4 m reinforcement elements of a smooth form.
If the installation step of the clamp is 0.5 m, the number of compounds will be: 24 / 0.5 + 1 \u003d 49 pcs. It means that based on the calculations, you will need 4x49 \u003d 196 meters of transverse and vertical rods.
The total area of \u200b\u200bthe reinforcement cross sections and its weight, based on the diameter of the rods, can be treated with the table:
Armature diameter, mm |
The calculated area of \u200b\u200bthe transverse rod, mm 2, with the number of rods | Theoretical mass of 1M length of reinforcement, kg | ||||||||
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | ||
| 6 | 28,3 | 57 | 85 | 113 | 141 | 170 | 198 | 226 | 254 | 0,222 |
| 8 | 50,3 | 101 | 151 | 201 | 251 | 302 | 352 | 402 | 453 | 0,395 |
| 10 | 78,5 | 157 | 236 | 314 | 393 | 471 | 550 | 628 | 707 | 0,617 |
| 12 | 113,1 | 226 | 339 | 452 | 565 | 679 | 792 | 905 | 1018 | 0,888 |
| 14 | 153,9 | 308 | 462 | 616 | 769 | 923 | 1077 | 1231 | 1385 | 1,208 |
The minimum area of \u200b\u200bthe reinforcement of the foundation is regulated by regulatory documents, and the strength of the foundation depends on
What scheme it is better to choose
There are two main reinforcement schemes that are most often used to strengthen the base for low-rise buildings:
- four twigs;
- six rods.
In accordance with SNiP 52-101-2003, adjacent rods of reinforcement should be located at a distance of 40 cm (400mm) in one row. Extreme longitudinal fittings should be at a distance of 5-7 cm (50-70 mm) from the side walls of the base. Therefore, if the width of the base is more than 50 cm, then it is better to use a six-rod reinforcement scheme.
Depending on this, the diameter of steel rods is chosen.
Usually, laying of "into the cell" rods is used for the ribbon base. In this case, all rods are attached at an angle of 90 °. For longitudinal location, the valves of class A3 are used having a round shape.
How to rein the corners
At the corners there are a large load. Therefore, during reinforcement, it is necessary to take care of their strengthening.
For This should be taken into account the following rules:
- prut must be bent so that one side of his side is plunged into one wall of the foundation, and the second one is in another wall;
- if the rod is insufficient length to make a bend, then for the attachment of rods on the corner you can use M-shaped profiles.
Most often for this is used class A3 fittings.
How to perform reinforcement with your own hands
To do this, you should take a square or a rectangle.
Before installing the frame on the bottom of the trench, you must lay out a sandy pillow with a depth of 1 m.
The frame is set in this way:
- on the bottom of the trench, bricks are placed, the height of which is 5 cm (in order to create a gap between the bottom of the base and the frame);
- to install the racket rods, it is necessary to make a sample in advance, according to which the rods will be cut;
- on bricks, rods of the longitudinal form are laid;
- to the longitudinal rods in 50 cm increments with knitting wire, the horizontal jumpers are tied with a length of a little less than the base thickness (approximately 5 cm on each side);
- the corners of the resulting cells fasten the rods vertically long 10 cm longs are less than the height of the base;
- top longitudinal rods are mounted to vertical reinforcement;
- top transverse rods are tied to the corners.
In the reinforcement of the belt foundation, it is necessary to adhere to the requirements of SNiP 52-01- 2003
The main provisions SNiP 52-01-2003
The main provisions of SNiP 52-01-2003 relate to the distance between the horizontal ribs of the steel frame and the diameter of the reinforcement. So, between the longitudinal rods should not be less than 25 cm and more than 40 cm.
The cross section of the rods is chosen according to the number of longitudinal rods. For a belt foundation, it should be at least 0.1% of the area of \u200b\u200bthe working section of the base. For example, if the foundation height is 1 m, and the width is 0.5 m, the cross-section area should be approximately 500 mm2.
Visually than the minimum diameter of reinforcement can be viewed in the table of examples:
| Terms of use of fittings | Minimum diameter of reinforcement | Regulatory document |
| Longitudinal workforce along the side of 3 meters or less | 10 mm | |
| Longitudinal workforce along the part of more than 3 meters | 12 mm | Reinforcement of elements of monolithic reinforced concrete buildings |
| Constructive fittings | The section is 0.1% of the cross-sectional area at the height of the distance between the armature layers and the half of the ribbon width | |
| Cross fittings (clamps) compressed elements | At least ¼ the largest diameter of longitudinal reinforcement and not less than 6 mm | |
| Cross fittings (clamps) knitted bending frames | not less than 6 mm | SP 52-101-2003 Concrete and reinforced concrete structures without pre-voltage of reinforcement. |
| Transverse fittings (clamps) of knitted frames of the height of section 80 cm and less | 6 mm | Concrete and Concrete Construct Construction Design Guide |
| Clamps of knitted frames of the height of section more than 80 cm | 8 mm | Concrete and Concrete Construct Construction Design Guide |
Reinforcement of the ribbon foundation is easy to perform with your own hands, it suffices to comply with technology and correctly calculate. If it is difficult to do it yourself, it is better to resort to help professionals. After all, reliable and durable foundation is the price and a guarantee of the sustainability of the whole building.
More information about the reinforcement of the belt foundation with their own hands can be viewed in the video:
Beton filled into the foundations under the building, after drying, becomes durable as a stone. But this does not mean that it can withstand any load. The accurate calculation will help withstand the weight of the construction, but there are other types of loads that are not compressed the foundation design, but stretch or bend.
From them, concrete construction cracks. That this does not happen, it is necessary to carry out the reinforcement of foundations, for which steel fittings are used, which is collected in the grid or lattice. The reinforcing frame is assembled according to a specific scheme, taking into account the diameter of the reinforcement. Therefore, before reinforcing the foundation, it is necessary to calculate the frame design.
Calculation of fittings
The calculation is based on the very loads acting on the foundation foundation of the house. And this is not only the weight of building materials, of which the building is built, it is furniture placed around the rooms, household appliances, utensils, clothes, weight of people living in the house, snow, rain and so on. Therefore, to independently make such a calculation if you are not a specialist in this area, it is impossible. To consider all the loads, even an experienced specialist will not be able. Therefore, there are special coefficients to which the parameters of the house are multiplied at the calculation of the share of building materials.
Calculators are installed on some construction portals by which the loads for the foundation for the house can be calculated. It is necessary to immediately say that the final result of this type of calculations is not accurate, its error is big. Therefore, the Council is to use the services of an experienced designer who accurately calculates the workload.
In principle, independently and approximately calculate the number and diameter of the reinforcement for the reinforcing framework can be. But before this it is necessary to understand what this design is present.
It consists of transverse and longitudinal rods, which are bonded between themselves with a knitting wire, electric welding or special couplings. Specialists recommend wire. If the conversation is about the reinforcement of monolithic This is a grid laid on the prepared foundation. Grids may be several, they are interconnected by vertically installed pieces of fittings of the same length.
If the reinforced belt is manufactured for, The grids are installed vertically, and among themselves they are fastened with horizontal pieces of fittings. Grids minimum may be two. At the same time, the reinforcement of the MZLF (small-breeding design), a swallowed or superficial foundations is carried out equally. The size of the reinforcing structure is simply changing, as well as the diameters used inside the reinforcement.
Example
For example, you can take the foundation for the garage. The internal dimensions of the room are 4 x 6 m, taking into account the thickness of the walls - 4.5 x 6.5 m. If a slab foundation is poured, the edges of the frame grid should not reach the edges of the foundation itself by 10 cm. It turns out that the size of the lattice is 3 x 6.3 m. If the thickness of the foundation plate is greater than 20 cm, the two grids are stacked one above the other. Garage - a small structure, so the optimal dimensions of the reinforcing stacks - 20 x 20 cm. It turns out that it is necessary to lay the rods every 20 cm.
- 630/20=31,5.
- 430/20=21,5.
The obtained values \u200b\u200bmust be rounded and add one to one rod, because this calculation does not take into account the extreme element of the mesh for the foundation. In the end, it turns out that it is necessary to put 23 rods with a length of 6.3 m, across 33 with 4.3 m long. The same amount will be required to the second grille. Now you need to calculate the number of reinforcement, the segments of which will be connected to each other two grids.
For example, if the thickness of the concrete screed is 20 cm, and the reinforcing belt itself should be located in the body of the concrete, then, respectively, from the bottom and upper plane, it is necessary to retreat 3-4 cm. It turns out that a distance of 12 - 13 cm remains between the plates reinforcement grids. This is the length of vertical segments of reinforcement. As for the quantity, it is necessary to take into account the installation step, which is equal to the side of the skeleton mesh cell, that is, 20 cm.
Video
Video about formwork and reinforcement of a belt small-breeding foundation.
Calculation of tape and columnar foundation
Reinforcement of the belt foundation, the calculation of the reinforcement, the laying and the binding is carried out, in principle, just as well. It is simply necessary to take into account that the reinforcing lattices in this design are not installed horizontally, but vertically. In this case, the length of the longitudinal rods depends on the length of the tape, and transverse from the depth of the foundation.
The ribbon width defines the number of lattices and the length of the rods connecting the grids. For example, if the width of the foundation tape is 40 cm, then a distance of 25 - 30 cm is left between the lattices, this is the length of the binding rods.
As for the quantity, again, everything will depend on the size of the sizes of the foundation of the foundation. For example, if the depth of the embedding is 1 m, and the frame is laid inside the concrete mass, then the distance from the upper surfaces is set to 10 cm on each side. Therefore, the length of the transverse rods will be 80 cm. And the number of longitudinal guides will be equal to 100/20 \u003d 5 rows.
The rules of the design of structures are very different from the two previous options. Firstly, These are vertically installed rods linted by a rod with a diameter of 6 mm or a small fittings. It all depends on the size of the support pillars themselves. Secondly, The frame cross section is either a square, or a circle, or a triangle.
The length of the main rods depends on the depth of the foundation. At the same time, there is no need to take into account the distance from the bottom of the well to the reinforcement, because the finished reinforcing design is installed directly on the prepared pillow. But the ledge of the rods in the amount of 10 - 70 cm will have to be traced, which will strike from the columns. They will be connected to the rustling grid.
Different types of foundations
Slab
SAMI simple scheme reinforcement at the slab foundation. As already mentioned, this is one or two lattices laid one above the other. The grille itself is most often assembled right at the location of the foundation. The reinforcement rods are decomposed in accordance with the sizes of the cells and reinforce the intersection places of knitting wire. The strapping schemes are quite a lot, if the construction assembly is carried out with their own hands, it is better to choose the easiest option.
Reinforced belt in one grid - This is a layout of fittings according to the scheme, their blockage and installation of the lattice on the backups. Scheme in two grids - This is exactly the same installation of the bottom grid, but the upper will have to be laid on special clamps from the reinforcement. They have a different look, one of them is shown in the photo below.
Reinforcement of the ribbon monolithic foundation is carried out, in principle, by the same technology. Only the frame itself is going away from the trench. Two grids are collected, which are connected to each other by segments of reinforcement. And the finished design is lowered inside the formwork. The device of the reinforced belt with a formwork is practically ready to fill the design. The only thing to pay attention to is to put the reinforced belt on the backups. For this purpose, one-piece bricks, stone or manufactured stands made of metal profiles are used.
In the construction of a ribbon design, an important element is reinforcing the corners of the foundation. It is here that all the stresses are collected. There are several technological schemes how to properly rein the corners. Each scheme has certain details of the assembly of the design and reinforcing fittings. Therefore, choose the one that is suitable for the conditions of the construction of the foundation.
For example, one of them is reinforcing with clamps. For the foundation in two meshs, two P - shaped clamps are necessary. They are installed on top of those laid in the corner of Armokarkas so that their ends look in the direction of the two jammed trenches. In this case, it is necessary to increase the compound, therefore, the clamps are connected to additional transverse fittings. In the photo below, they are shown at number 4.
Columnar
The reinforcement of piles should be approached from the position of the vertical installation of the Armoconstruction. Before reinforcing a column foundation, it is necessary to understand that this vertical installation Several reinforcement rods, which are connected by each other from the reproduction of smaller diameter reinforcement. As practice shows, most often this design is collected by the method of electrical welding with subsequent metallization of the joints. Designs are collected separately from wells and installed in them as a finished product.
Since the column foundation, for example, under the column is collected as the column itself and the concrete pillow under it, then, in fact, the reinforcement of a step foundation should be.
To do this, you will have to collect a separate reinforced frame for the column and for the pillow.
Since the size of the latter is superior to the first, then under pile Fundam This type is digging a well with a cross section than the sizes of the pillow.
- After that, the formwork is assembled for the pillow.
- Installed reinforced frame.
- Next, the skeleton of the column is installed on top, which is tied to the reinforcement of the pillow.
- And the last stage - setting the column formwork.
If simple piles are reinforced for light buildings in wells, then to connect together with each other, further paints. In fact, it is a ribbon foundation, which means that the reinforced belt is laid, as in the belt design.
It is necessary to add that for the reinforcement of a monolithic columnar foundation with painter, the accurate calculation of the loads acting on the structure and from the framework of the frame. So, you will have to accurately calculate the number of reinforcement rods in the design and their diameter.
At the same time, special attention is paid to the compound of the rods of the Armokarkas pillars with the turnover of the Turks. Protruding from the post ends of the reinforcement bend at an angle of 90 ° so that:
- One of them part laying the bracket to the rods of the top lattice.
- Other to the rods of the bottom grid.
And it is better if the bending will be carried out in different directions of the arrangement of the ribbon frame in half from the number of rods, as shown in the photo below.
The ribbon reinforcement of the pile - a ribbon foundation is a single design consisting of two multidirectional frameworks. Therefore, in places of connection two parts, it is necessary to carry out measures to enhance compounds. So one of the rules states that the perfect nast of fittings of two connected structures should not be less than 60 cm. And it means that the reinforcement rods must be output from the columns, at least 80 cm. This is taking into account the bend.
Often to the reinforcement of piles and woodworks are suitable from the position of the rapid production of the frame. What is used electric welding. It is in places of connection two designs this is not recommended. Loads are too large here, especially on bending. Therefore, advice - use with knitting wire. Moreover, this process does not require high costs and skills.
We add that it is necessary to approach the construction of the foundation and its reinforcement from the position of a properly selected design. If the support pillars have a small diameter, the design of three rods with a triangular cross section will fit. In other cases, a square or round design is used. The first one is easier to manufacture.
Conclusion on the topic
Questions relating to the reinforcement of various foundation designs, a lot: why and why reinforce which it is better to use fittings for this, how to make reinforcement correctly, which connection scheme is better and so on. It should be understood that everything will depend on the loads that act on the foundation design. Therefore, returning to the beginning of the article, it is necessary to accurately calculate these loads.. And already based on them to choose and the reinforcement, and the scheme of its assembly.
Today, many issues are asked about such a process as the reinforcement of the foundation of fiberglass reinforcement. This is a good material that does not rust. But he has a low carrying capacity, therefore, it is not recommended to lay this look into foundations that are subject to large loads. By the way, the strapping fiberglass fittings produced by plastic clamps.
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