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 poured slab foundationThe edges of the frame grille should not reach the edges of the foundation of 10 cm. It turns out that the size of the lattice is 4.3 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 blocking of fiberglass reinforcement is made by plastic clamps.
In contact with
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 for ribbon base The laying of rods "into the cell" are used. 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:
Events on the construction of any building are preceded by project work, in the process of which the type of foundation base is determined and the required amount of materials for its structure. An important part of the foundation is an armature framework. It increases the strength of the base, damping stretching efforts and bending loads, and also prevents the formation of cracks. To perform work, it is necessary to understand how many fittings are needed for reinforcing a belt foundation, as well as for a columnar and slab base. We will deal with the features of computing.
Flow of reinforcement for reinforcement of a belt foundationPreparing to calculate the number of reinforcement for foundation - Important moments
Planning the construction of a private house, you should pay special attention to the design of the reinforcement lattice, which perceives significant loads on the foundation. A qualified developed scheme of the power grid and the use of the optimal section of the reinforcement makes it possible to ensure the required margin of the safety of the foundation base, as well as its long-term use resource.
- using software and online calculators that perform the calculation of the valves after the operation of the operating parameters;
- performing calculations manually based on information on the design features of the foundation, the magnitude of the effort and the lattice parameters.
The foundation base, perceives the load from the mass of the building and evenly distributes it to the support surface of the soil.
Building construction is carried out on different types of foundations.:
- tapes;
- slab;
- stated.
Calculation of reinforcement for a belt foundation Prior to the start of computation, it is necessary to deal with the structure of the power frame, which consists of the following elements:
- vertical and transverse rods, between which an equal interval is set;
- knitting wire connecting longitudinally located jumpers and vertical rods;
- the couplings providing a solid connection and extension of reinforcement rods.
For each type of base, the foundation is applied, which depends on the following factors:
- characteristics of the soil;
- gabarites of the building;
- structural features of the structure;
- existing loads.
Applied fittings having a ribbed surface that is different:
- section size;
- class;
- levels of perceived loads;
- location in the power grid;
- cost.
Laying fittings in a ribbon foundation For different foundations Based on the calculations, the following information is determined.:
- number of reinforcement for the foundation;
- vertical and transverse rods;
- the total mass of the reinforcement frame;
- methods for fixing steel rods in power structures;
- the technology of assembling the carrier lattice;
- pitch strapping of reinforcement elements.
It is important to fulfill the calculation correctly. Armature for the foundation in this case will provide the necessary margin of safety. Consider what source data are needed for calculations, as well as study the methodology for performing calculations for various types of foundations.
Calculation of the number of reinforcement for a ribbon foundation
The base of the belt type provides increased stability of buildings on various soils. The design is a concrete tape that repeats the contour of the building and located under capital walls. Strengthening steel reinforcement increases the strength characteristics of the concrete base and has a positive effect on its durability. For the construction of a spatial grid, it is possible to use the reinforcement with a diameter of 10 mm.
Source data for calculations:
- length and width of the foundation base;
- concrete ribbon cross section;
- interval between frame elements;
- the total number of strapping belts;
- the size of the cells of the power grid.
How many fittings need for foundation Consider the procedure for calculations:
- Calculate the total length of the belt circuit.
- Calculate the number of items in the belts.
- Determine the horizontal rod metra.
- Calculate the need for vertical struts.
- Calculate the length of the transverse jumpers.
- Fold the received metra.
Knowing the total number of butt plots, you can calculate the need for knitting wire.
Calculation of the number of reinforcement on the foundation of the slab type
The foundation of the slab construction is used to build residential buildings on bunny soils. To provide strength characteristics, reinforcement rods with a diameter of 10-12 mm are used. With an elevated mass of buildings, the diameter of the rods should be increased to 1.4-1.6 cm.
- the spatial frame of fittings is constructed in two levels;
- the connection of the rods is performed in the form of square cells with a side of 15-20 cm;
- the strapping is performed by an annealed wire at each connection point.
The scheme of reinforcement of the foundation monolithic plate To determine the need for fittings, follow these operations.:
- Determine the number of horizontal rods in each tier.
- Calculate the overall method of reinforcement cores forming cells.
- Add the total length of the vertical supports that combine tiers.
Folding the values \u200b\u200bobtained, we obtain the overall need for fittings. Knowing the number of joints is easy to determine the required volume of steel wire.
How to calculate fittings for the foundation of the column design
The base of the column type is widely used for the construction of various buildings. It consists of reinforced concrete supports of a square and round section mounted in the corners of the structure, as well as at the points of intersection of capital walls and internal partitions. To increase the strength of the reference elements, the ribbed rods of 1-1.2 cm cross section are used.
- the framework of the reference element of the square profile is formed from 4 rods;
- the grille of the reinforced concrete support of the circular section is performed from three rods;
- the length of the gain elements corresponds to the sizes of the support column;
- the crossbase of the support column is performed in 0.4-0.5 m increments.
Algorithm for calculating the consumption of fittings of the foundation - Determine the length of the vertical rods in one support.
- Calculate the metratem of the crossbar of one frame.
- Calculate the total length by folding the values.
Multipling the result on the number of supports, we obtain the total length of the reinforcement.
How to calculate the fittings for foundation - an example of calculations
As an example, consider how much fittings need for the foundation 10x10, formed in the form of a monolithic reinforced concrete tape.
To perform calculations, use the following information.:
- the width of the base is 60 cm, allows you to put in each belt 3 horizontal rods;
- 2 reinforcement belts are performed connected by vertical rods with an interval of 1 m.
- for the building 10x10 m and the depth of the base of 0.8 m, the armature is used with a diameter of 10 mm.
Flow of reinforcement for ribbon foundation - We determine the perimeter of the foundation base of the building, folding the length of the walls - (10 + 10) x2 \u003d 40 m.
- Calculate the number of horizontal elements in one belt, multiplying the perimeter on the number of rods in one tier - 40x3 \u003d 120 m.
- The total length of longitudinal rods is determined by multiplying the resulting value to the number of tiers 120x2 \u003d 240 m.
- We calculate the number of vertical elements set by 10 pairs per side 10x2x4 \u003d 80 pcs.
- The total length of the vertical rods will be 80x0.8 \u003d 64 m.
- We determine the length of the jumpers with a size of 0.6 m each mounted on two belts (20 to side) - 10x2x4x0.6 \u003d 48 m.
- Folding the length of the reinforcement rods, we obtain a common meter 240 + 64 + 48 \u003d 352 m.
Determine the length of the steel wire is easy. The number of compounds multiplied by the length of one piece of wire, equal to 20-30 cm, will give a desired result.
We sum up - how much the calculation of the fittings for the foundation
When planning the construction of a house, a bath or country structure, it is easy to determine the need for fittings with your own hands. Step-by-step instructions will allow the calculator to calculate the Method of rods for the manufacture of the reinforcement lattice, which enhances the foundation of the building. Knowing how to calculate the reinforcement, you can independently perform calculations without resorting to the help of third-party specialists. Properly performed calculations will ensure the strength of the foundation base, the stability of the building, as well as a long service life.
The foundation is the most responsible building design. After the backstage of the pit, access to it is limited, and the correction of any deficiencies becomes a challenge. It is important to ensure sufficient structure strength still at the design stage.
Concrete works greatly on compression, but does not cope with the bend. The soil is considered a elastic base that does not prevent small fondament tape deficits. To increase the strength of the structure, the longitudinal steel rods are laid under the transverse load.
All fittings in the design is divided into two types: working and structural. In the ribbon foundation, longitudinal rods become working reinforcement. They are chosen by the calculation. Constructive reinforcement is appointed from the minimum requirements of regulatory documents, the calculation is not carried out. They are installed for the collaboration of individual longitudinal rods.
Figure classes and steel brands
Armature is different not only with a diameter. It is very important to choose the right class of products. Rod steel is indicated by marking A, and wire BP. For foundation, metal class is used by the yield strength A400 (AlLL - outdated marking). The rods are easily distinguished visually:
- A240 (AL) - smooth surface;
- A300 (ALL) - Periodic profile with a ring pattern;
- The necessary for the foundation A400 (AllL) is a periodic sickle profile, or as elsewhere called the Christmas tree.
It is allowed to apply reinforcement of higher classes, but in most cases it is not economically profitable. Lowering class of valves is not allowed.
In the manufacture of rods are guided. According to this document, the A400 class reinforcement is made of steel with stamps 5GS, 25G2C, 32G2RS. The consumer chooses what raw materials apply. In the absence of brand steel in order, GOST allows the manufacturer to assign it independently.
In addition to the regulatory document, the rules for accepting fittings, test methods, conditions for transportation and storage are indicated.
Minimum diameters of fittings
When calculating, the total area of \u200b\u200ball working reinforcement is calculated, and the amount and section of individual rods is already selected by the sort.
For convenience, the limit on the diameters is reduced to one table.
The requirement for the recruitment of the working reinforcement is given in. This 2012 document is a topical editorial board of the SNiP of the same name, issued in 2003. The main information in the documents is identical, only small changes are made. More detailed instructions are presented in the manual for the design of concrete and reinforced concrete structures without pre-voltage of reinforcement.
The diameter of more than 40 mm cannot be used for concrete structures.
Calculation of working reinforcement
When erecting serious structures, detailed calculations of the belt foundation are required, which accurately determine which fittings to use for this design. All settlements in construction are carried out by limit states, that is, the minimum conditions are defined in which the element will perform its function.
- The first group of limit states is a strength calculation. The reliability and safe operation of the design is ensured.
- The second group of limit states is the calculation of rigidity. Prevents excessive disclosure of cracks, skews, great defamations.
Calculations according to data formulas and require technical education. To simplify the design of small private buildings, the reinforcement of the belt foundation is taken on the basis of the minimum values.
Example of calculating rods for a tape foundation
Initial data:
- tape height - 100 cm;
- ribbon width - 40 cm.
It is required to descript the frame for an individual residential building. Used longitudinal, transverse and vertical fittings. The vertical is taken by a cross section of 8 mm and is installed in a step 25 cm. The transverse horizontal is mounted with the same step, but with a diameter of 6mm.
In order to determine which work fittings need a simple calculation
- The cross-sectional area of \u200b\u200bthe foundation \u003d width * height \u003d 100 cm * 40 cm \u003d 4000 cm².
- The required area of \u200b\u200bcross-section of reinforcement rods \u003d 0.1% * 4000 cm² \u003d 4 cm².
| Armature diameter, mm | Total estimated cross-sectional area of \u200b\u200breinforcement rods, cm 2 | Mass of 1 meter of reinforcement, kg | ||||
| 2 rod | 4 rod | 6 rods | 8 rods | 10 rods | ||
| 8 | applies only at the height of the foundation 15 cm and less, which is not suitable for ribbon structures | 2,01 | 3,02 | 4,02 | 5,03 | 0,395 |
| 10 | 3,14 | 4,71 | 6,28 | 7,85 | 0,617 | |
| 12 | 4,52 | 6,79 | 9,05 | 11,31 | 0,888 | |
| 14 | 6,16 | 9,23 | 12,37 | 15,39 | 1,21 | |
| 16 | 8,04 | 12,06 | 16,08 | 20,11 | 1,58 | |
| 18 | 10,18 | 15,27 | 20,36 | 25,45 | 2,0 | |
| 20 | 12,56 | 18,85 | 25,13 | 31,42 | 2,47 | |
For this belt foundation, the minimum diameter is equal to 12 mm according to the document "reinforcement of elements of monolithic reinforced concrete buildings. Design allowance ", and accept it. A variant will need 4 rods: 2 are located below and 2 top.
If the rods of different diameters are used (those that are available), the rods of large sizes are located below.
Calculation of the number of reinforcement for the foundation
Initial data:
- materials are indicated in the previous paragraph;
- the length of the walls of the ribbon foundation is 40 m.
- Length: the perimeter of the building * The number of rods in the section + reserve for the nourishing during the welding of rods \u003d 40 * 6 + 5 \u003d 245 m.
- Anchoring of the angles: the number of rods in the section * The number of angles * The minimum length of anchoring (50 diameters of the reinforcement) \u003d 6 * 4 * (50 * 12) \u003d 14.4 m.
- Mass: Length * Mass of one meter \u003d (245 + 14.4) * 0,617 \u003d 230.3 kg of rods with a diameter of 12 mm.
Constructive horizontal reinforcement
The length of the rods is made depending on the width of the tape wall less than the protective layer of concrete - 2-3 cm on each side. We accept longitudinal rods 34 cm.
- Total length: Quantity * Length of one rod \u003d 160 * 0.34 \u003d 54.4 m.
- Mass: 54.4 * 0,222 (in the table above is not indicated, but there is in a complete range) \u003d 12.1 kg by rods with a diameter of 6 mm.
Constructive vertical reinforcement
All as in the previous paragraph, the rods are set long equal:
The height of the belt foundation minus 3 cm * 2 \u003d 100 - 3 * 2 \u003d 94 cm.
- The number of rods: the perimeter of the building / pitch of the clamp (in the previous paragraph, it is received 25 cm) \u003d 40 / 0.25 \u003d 160 pcs.
- Total length: Quantity * The length of one rod \u003d 160 * 0.94 \u003d 150.4 m.
- Mass: 150.4 * 0.395 \u003d 59.41 kg Rods with a diameter of 8 mm.
For convenience, the figures obtained can be reduced to the table.
The calculation of the diameter of the reinforcement takes no more than 10 minutes, but will avoid material overpowering or the cost of repairing tape foundations. The table obtained in the last paragraph is convenient to use when buying a material.
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Reinforcement of the belt foundation significantly increases its characteristics by strength, allows you to create stable structures while reducing weight.
Calculations of reinforcement and reinforcement scheme are performed according to the provisions of the current SNIPA 52-01-2003. The document has detailed calculations requirements, gives a footnote to regulatory documents and rules.
SP 63.13330.2012 Concrete and reinforced concrete structures. Basic provisions. Actualized edition Snip 52-01-2003. File for download
The ribbon foundation must meet the extensions for durability, reliability, resistance to various climatic factors and mechanical loads.
The main characteristics of the strength of concrete structures is an indicator of resistance to axial compression (Rb, N), stretching (RBT, N) and cross-influence. Depending on the normative standard indicators of concrete, its specific brand and class is selected. Taking into account the responsibility of the structure, the correction rates of reliability can be used, which fluctuate from 1.0 to 1.5.
Requirements for fittings
During reinforcement of belt foundations, the view and controlled values \u200b\u200bof the quality of the valves are established. Standards allowed to use hot-rolled construction reinforcement of a periodic profile, thermally processed fittings or mechanically hardened fittings.
The assembly class is selected taking into account the guaranteed yield strength value at maximum loads. In addition to the characteristics of the stretching, plasticity is normalized, resistance to corrosion, weldability, negative temperature resistance, relaxation resistance and permissible elongation before the start of destructive processes.
Table of fittings and steel brands
| Profile type | Class | Diameter, mm. | steel grade |
|---|---|---|---|
| Smooth profile | A1 (A240) | 6-40 | ST3KP, ST3PS, ST3SP |
| Periodic profile | A2 (A300) | 10-40, 40-80 | ST5P, ST5PS, 18G2C |
| Periodic profile | A3 (A400) | 6-40, 6-22 | 35GS, 35G2C, 32G2RPS |
| Periodic profile | A4 (A600) | 10-18 (6-8), 10-32 (36-40) | 80С, 20ХГ2Ц |
| Periodic profile | A5 (A800) | 10-32 (6-8), (36-40) | 23x2g2t |
| Periodic profile | A6 (A1000) | 10-22 | 22x2g2a, 22x2g2p |
The calculation of the belt foundation is made in accordance with the recommendations of GOST 27751, the indicators of limit loaded states by groups are calculated.
The first group includes the states leading to the complete unusability of the foundation, the second group includes the states leading to partial loss of sustainability, which make it difficult to normal and safe operation of buildings. At the maximum permissible states of the second group produced:
- calculations for the appearance of primary cracks on the surface of the belt foundation;
- calculations at the time period of increasing the resulting cracks in concrete structures;
- calculations on linear deformations of ribbon foundations.
The main indicators for the stability of the deformation and strength of construction fittings include the maximum strength when tensile or compression, determined in the laboratory conditions on special test benches. Technology and test methods are spelled out in state standards. In some cases, the manufacturer can use the regulatory and technical documentation developed by the enterprise. At the same time, the regulatory and technical documentation must necessarily be approved by the regulatory authorities.
For concrete structures, these values \u200b\u200bmay be limited to maximum indicators of concrete linearity. As generalized indicators, actual values \u200b\u200bof the state of reinforcement are taken with a short-term unilateral impact of the calculated regulatory loads. The nature of the status diagrams of the construction reinforcement is established with its specific species and brand. During the engineering calculation of the reinforced foundation, the status diagram is determined after the replacement of the normative indicators is actual.
Requirements for reinforcement
Armature frame - Photo
- Requirements for the size of reinforced concrete design. The geometric sizes of the foundation should not prevent the correct spatial location of the reinforcement.
- The protective layer must provide joint resistance to the loads of reinforcement and concrete, to protect against the exposure to the external environment and ensure the stability of the structure.
- The minimum distance between individual rods of reinforcement should ensure joint work Its with concrete, allow you to correctly stick and ensure the proper technological fill of concrete.
For reinforcement, you can use only high-quality reinforcement, the knitting of grids is performed taking into account the calculated design indicators. Deviations from values \u200b\u200bcannot exit the tolerances regulated by SNiP 3.03.01. Special construction activities should ensure reliable fixation of the reinforcement grid according to the existing rules.
SNiP 3.03.01-87. Carriers and enclosing structures. Building regulations. File for download
During the bending of the reinforcement, it is necessary to use special devices, the minimum bend radius depends on the diameter and the specific physical characteristics of the construction reinforcement.
Prices for reinforcement grid
reinforcement grid
Video - manual machine for reinforcement bending, video instruction
Video - how to bend fittings. Work on a homemade machine
The reinforcement is inserted into the formwork, the manufacture of formwork should be carried out taking into account the requirements of GOST 25781 and GOST 23478.
Steel forms for the manufacture of reinforced concrete products. Technical conditions. File for download
Formwork for the construction of monolithic concrete and reinforced concrete structures. Classification and general technical requirements
Calculation of the number and diameter of the reinforcement
For a ribbon base of baths, construction fittings applied with a periodic profile Ø 6 ÷ 12 mm.
Existing state regulations regulate minimal amount Rods in concrete to give it maximum strength characteristics. The minimum total cross-section of the longitudinal rods of the reinforcement can not be ≤ 0.1% of the section of the foundation tape cross section. For example, if the ribbon foundation has a section of 12000 × 500 mm (the cross-section area is 600,000 mm2), then the total area of \u200b\u200ball longitudinal rods should be at least 600,000 × 0.01% \u003d 600 mm2. In practice, developers rarely withstand this indicator, also the weight of the bath, the nature of the soils and the concrete brand of concrete is also taken into account. This calculated value can be considered approximate, deviations from the recommended values \u200b\u200bshould not exceed ≈20% in a smaller side.
To calculate the number of reinforcement, you need to know the area of \u200b\u200bthe section of the foundation tape and the cross-sectional area of \u200b\u200bthe reinforcement bar. To facilitate the execution of calculations, we bring to your attention a ready-made table.
| Number of rods | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Diameter, mm. | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
| 6 | 28,3 | 57 | 85 | 113 | 141 | 170 | 198 | 226 | 254 |
| 8 | 50,3 | 101 | 151 | 201 | 251 | 302 | 352 | 402 | 453 |
| 10 | 76,5 | 157 | 236 | 314 | 393 | 471 | 550 | 628 | 707 |
| 12 | 113 | 226 | 339 | 452 | 565 | 679 | 792 | 905 | 1018 |
| 14 | 154 | 308 | 462 | 616 | 769 | 923 | 1077 | 11231 | 1385 |
| 16 | 201 | 402 | 603 | 804 | 1005 | 1206 | 1407 | 1608 | 1810 |
| 18 | 254,5 | 509 | 763 | 1018 | 1272 | 1527 | 1781 | 2036 | 2290 |
| 20 | 314,2 | 628 | 942 | 1256 | 1571 | 1885 | 2199 | 2513 | 2828 |
Now the calculations are greatly facilitated. For example, for reinforcing a ribbon foundation, you use eight rows of reinforcement with a diameter of 10 mm. According to the table, the total area of \u200b\u200bthe rods is 628 mm. Such a frame can work with a concrete ribbon depth of 120 cm and 50 cm wide. Several extra square millimeters can not be taken into account, they will be additional insurance in case of violation of the mating technology or the manufacture of poor-quality concrete.
In addition to these indicators, it is necessary to determine the diameters of the rods for the foundations. These indicators depend on many components, you can use the proposed table for simplified calculations.
Using this table, you can easily select the recommended diameter of the reinforcement for a ribbon foundation.
Rules of Ribbon Foundation
There are several armature mating schemes, each developer can enjoy the most convenient for himself. The selection of the scheme should be carried out taking into account the size of the foundation and its supporting characteristics.
The reinforcement can be kniting separately, and then the finished elements of the design omit in the trench of the foundation and interleve each other, and you can immediately knit into the trench. Both methods are almost equal, but there is a small difference. On Earth, all the main rectilinear elements can be made independently, an assistant is required when working into the trench. For mating you need to make a special hook, the compound is performed with a soft wire with a diameter of ≈0.5 mm.
In some articles you can find tips during the mating use a manual electric drill - do not pay attention to them. So can write those who have no idea about work.
First, from a drill, the hand will get tired much more and faster than from the light hook. Secondly, under the legs will always be fought cables, cling to the ends of the reinforcement, etc. Thirdly, there is no electrical energy in all construction sites. And, fourthly, you have nodes from the wire will constantly either be closed or torn.
For mating fittings, fine soft and wire applies, and it has low strength. Tensioner wire well, durable binding should occur in two or three hook turnover. Otherwise, labor productivity is much reduced and fatigue increases. There are still options for welding fittings, we will talk about them in the next section of the article.
Knitting Wire prices
knitting wire
How to knit reinforcement grid yourself
We already said above that this way you can knit fittings on Earth. Only the rectilinear areas of the grid are manufactured, the angles are tied after their lowering into the trench.
Step 1. Prepare pieces of fittings. The standard length of the rods is six meters, if possible, you do not need to touch them. If you fear that with such dinah it will be difficult to work - cut them in half.
We advise you to start knitting fittings for the shortest ribbon foundation site, it will provide an opportunity to acquire a little experience and more confidently cope with long ruts. It is not recommended to cut them, it increases the metal consumption and reduces the strength of the foundation. The dimensions of the blanks Consider on the example of a ribbon foundation with a height of 120 cm and a width of 40 cm.
The reinforcement should be filled with concrete with a thickness of at least 5 centimeters. These are the starting conditions. Taking into account such indicators, the pure dimensions of the reinforcement frame should be at a height of no more than 110 cm (minus 5 cm on each side) and in width of 30 cm (minus 5 cm on each side). For mating you need to add two centimeters on each side to the nahby. So, the billets for horizontal jumpers must have a length of 34 cm, the blanks for vertical jumpers must have a length of 144 cm. But such a high frame should not be done, it is enough to have a height of 80 cm.
Step 2. Choose a flat pad, put two long bar, fill their ends.
Step 3. At a distance of ≈ 20 cm from the ends, tie the horizontal struts on both extremes. For mating you need a wire length about 20 centimeters. Fold it twice, impose at the binding site and tighten the wire with an ordinary scrolling of a knitting hook. Do not overdo it with an effort, the wire may not withstand. The magnitude of the twisting effort is determined by the experimental way.
Step 3. At a distance of approximately 50 centimeters, tie the all the remaining horizontal struts in turn. Everything is ready - to postpone the design to a free space and make another part of the framework in the same way. You got the upper and lower part, now you need to make them together.
Step 4. Next, you should adjust the stops for the two parts of the grid, you can rest them to any subject. The main thing is that the associated elements occupy a steady lateral position, the distance between them should be equal to the height of knitted reinforcement.
Step 5. On the ends to tie two vertical struts, you already know the sizes. When the frame has become more or less reminded ready product - Tie all other pieces. Do not rush, check all sizes. Although you have a blank and the same length, the size check does not hurt.
Step 6. By the same algorithm you need to associate all direct portions of the framework on Earth.
Step 7. Put on the bottom of the trench of the foundation of the lining with a height of at least five centimeters, the lower rods of the grid will lie on them. Put the side supports, set the grid in the correct position.
Reinforcement (frame set to formwork)
Step 8. Remove the dimensions of unbound corners and joints, harvest the pieces of fittings for connecting the frame into a single design. Keep in mind that the nesting of the ends of the reinforcement should be at least fifty diameters of the rod.
Step 9. Tie the bottom turn, then vertical racks and top to them. Check the reinforcement distance to all formwork surfaces.
Reinforcement is ready, you can begin the fill of the foundation concrete.
Knitting fittings using a special device
For the manufacture of the device you will need several boards with a thickness of about 20 mm, the quality of sawn timber can be arbitrary. Make a template is not difficult, and it will be simplified significantly.
Step 1. Cut four boards along the length of the reinforcement, connect them two at a distance of the vertical racks. There should be two identical templates. Make sure that the markup of the distance between the rails is the same, otherwise there will be no vertical position of the connecting elements.
Step 2. Make two vertical backups, the height of the backup must be responsible to the height of the reinforcement grid. The backups must have side corner stops that do not allow them to tip over. All works on viscosity should be carried out on a flat site. Check out the stability of the collected adaptation, eliminate the likelihood of its overturning on time.
Step 3. Put the legs of the stops into two shotguns, two top boards set on the upper shelf of the stops. Secure their position in any way.
You got a layout of the reinforcement grid, now work can be performed quickly and without assistance. Set the vertical strips of reinforcement on the placed places, pre-with nails temporarily secure their position. For each horizontal metal jumper, put the bar of reinforcement. This operation should be repeated on all sides of the frame. Check their position again. All right - take the wire and hook and start knitting. The device is advisable to do if you have a lot of identical grid areas from fittings.
Video - How to knit fittings with fixture
How to knit reinforced grid in trench
Working in the trench is much more complicated due to cramped conditions. It is necessary to think about knitting a knitting scheme of individual elements so as not to be then crawled between the rods of the reinforcement. In addition, it will not work independently to associate the grid, you need to work with the assistant.
Step 1. Put on the bottom of the trench of stones or bricks with a height of at least five centimeters, they raise the metal from the ground and allow concrete from all sides to close the reinforcement. The distance between the stones should be equal to the width of the grid.
In the photo - the retainer for Armokarkas
Step 2. On the stones you need to put longitudinal rods. Horizontal and vertical rods should already be cut in size, how to measure them already told.
Step 3.. Start forming a skeleton of a frame on one side of the foundation. If you first lend to the horizontal struts lying bar, it will work easier. The assistant must hold the ends of the rods until they are fixed in the desired position.
Step 4. In turn, continue to knit fittings, the distance between the struts should be approximately fifty centimeters.
Step 5. By the same algorithm, tie the reinforcement on all rectilinear areas of the foundation tape.
Step 6. Check the size and spatial position of the frame, if necessary, you need to correct the position and eliminate the touch of metal parts to the formwork.
Step 7. Now it's time to go to the corners of the foundation. In the picture, this is a fairly difficult version of knitting in the corners, you can come up for yourself easier. The main thing is to respected the length of the adhesive. And one more remark. In the corners, the foundation works not only on bending, but also for a vertical gap. These efforts keep the vertical rods of construction reinforcement, do not forget to install them. For warranty for these purposes, it is possible to use fittings with a large diameter.
You need to know that any welding impairs the physical characteristics of the strength of the reinforcement, use this method only in extreme cases.
If you still have to use welding, then do our best to impose a minimum number of seams in one place, slide a step of fixing horizontal and vertical stops into several centimeters. During the welding, we accurately hold the optimal indicators of the current strength and the diameter of the electrodes. Metal In places, the seam imposition should not overheat.
Welding fittings - Photo
And the most important thing - only special fittings are suitable for welding, the brand of such reinforcement is indicated by the letter "C". By the way, this fittings are much more expensive than ordinary.
There are several ways with which you can speed up and facilitate the mating process and at the same time improve the quality of the design and reduce the consumption of materials.
For the strut, bend the reinforcement in the form of the letter "P". To do this, you can make an elementary machine in a couple of hours, and it will be useful not only for flexible rods. First you need to bend one sample, check its dimensions and only then using the sample as a template, to prepare all connections. Such spacers are much easier to knit, they immediately keep the desired structure size. Another plus is reduced consumption of expensive material. At first glance, savings seem insignificant, maximum ten centimeters on one connection. But if you multiply ten centimeters by the number of pieces and the price of reinforcement, then it will be very "pleasant" amount.
For struts, you can use the reinforcement of a smaller diameter and an optional expensive construction periodic profile. Even metallic rods or the rolling of the corresponding diameter are suitable.
If you do not have any experience of doing such work, it is better to do it yourself. The presence of an assistant much facilitates the process and makes it more secure.
By price reinforced foundation Much more expensive than ordinary, use this method of enhancing architectural structures in extreme cases. There are many cheaper ways to increase the bearing characteristics of the belt foundation. True, they can not always be used, it all depends on the characteristics of the project of the bath, the characteristics of the soils and the landscape.
Several words can be said about pre-loaded reinforcement. This is a complex method that allows you to significantly improve all indicators of the belt foundation without increasing the number of reinforcement. The essence of the method consists in preliminary loading of rods with efforts oppositethat will act on the design during the operation of the foundation. For example, if the rod will work on stretching, then it is pre-squeezed, etc.
Video - reinforcement of monolithic tape foundations for shallow downlock
Video - reinforcement of the foundation with their own hands
