The production of reinforced steel, as well as the release of goods from other industries, is unified. To determine the quality of products, use is made of specially developed Gosstandart requirements for products according to different parameters. In this type of production, standards for diameter, weight and section of rods are set. All these characteristics are united by one term – a range of fittings. More details about the complex requirements will tell this article.
Scope of application, features of fittings: diameter, classes, marking, compliance with GOST
Armature is an important component in the general list of building materials. It is characterized by a wide range of applications at various stages of the construction of buildings. Not a single reinforced concrete structure, which serves as reinforcement and support both in the foundation of a small house and in the construction of a large-scale railway bridge or overpass, does not do without it. Reinforcement technology is used even for hardening glass structures.
Even at the initial stage of development of design and estimate documentation, every self-respecting engineer and architect has on hand a special table of ratios of the weight and metric area of the reinforcement, as well as the sections of the reinforcing bars in accordance with the established state standards. The main among them is GOST 5781-82. Also, products must comply with GOST 52544-2006, STO ASChM 7-93, TU 14-1-5254-94. The rules regulate the requirements for a specific type of reinforced products. Their combination corresponds to the term – a range of reinforcement.
The armature is a round metal rods with a smooth or corrugated surface. Produce them from several types of steel. The diameter of the rods ranges from 4 to 80 mm. The product range is divided into classes A1 – A6.
The diameter, that is, the size of the cross section of the reinforcement bar or wire, is the main indicator underlying the product mix. Hence the relevant terms: fittings of 8 mm or weight of 1 m of fittings 12. These products are also classified according to other properties, including strength, wear resistance, specific gravity and other characteristics, which will be considered further.
The word assortment (or assortment), in French, sounds like assortir and means “to choose,” that is, to sort it out by grade according to typical characteristics. These parameters include:
- the material used to manufacture the product;
- dimensions of reinforcement, such as size, diameter, type of surface;
Helpful advice! Packaging of products is carried out according to its classification by diameter. Reinforced metal to 10 mm released in coils, and over this parameter is Packed rods of a certain length.
The reinforcement is used in construction work in the form of rods, mesh, wire or frame. Based on the purpose, it is divided into constructive, anchor, mounting or working. This takes into account the presence or absence of tension, as well as the need to strengthen the design in a particular area. Gain may be longitudinal or transverse.
They mark and classify reinforcement according to other characteristic features, but first of all they take into account the diameter of the reinforcement, as well as the degree of strength, flexibility and mechanical characteristics. The symbol in the marking of the product are capital letters A (less often B) with a certain index, which indicates that the reinforcement corresponds to a separate class. The main and most popular classes of reinforcement in construction will be considered in this article.
In construction terminology and labeling, even professionals are sometimes confused. Different types of materials, including fittings, have their own classification, which makes it possible to simplify and unify many processes as much as possible.
To orient in the classification and labeling will help a special table of reinforcement classes. It has a fairly simple and understandable structure, consists of several columns, where the first is the main marking, and then the relevant characteristics:
- section size or diameter;
- resistance to stress;
- embeddability in stressed reinforced concrete structures;
- the relative amount of elongation after rupture;
- rod length;
- steel grade.
The table may contain more extended information, for example, allowing to calculate the weight of a meter of reinforcement or, conversely, calculate how many meters per ton of reinforcement are 12 mm. For novice builders suitable simplified version, with a minimum of background information.
The reinforcement class includes several numeric and alphabetic designations that determine its strength, size and purpose. At the same time, according to the table of the range of fittings, GOST 5781 82 regulates the old and new marking. The old belong to products belonging to the classes from AI to AVI. Accordingly, the new designate in this way: A240, A300, A400, A500, A600, 800 and A1000.
The A240C class armature has a smooth external structure, while the products with the marking A300C, A400C, A500C, as well as A600, A600K, A800, A800K and A1000 have a grooved surface.
Helpful advice! There is a certain encryption of the fittings, which has the following form: A-400-C fittings O12. Where the letter A denotes the marking of the material, the number 400 is the reinforcement class, 12 is the diameter of the rod.
Each reinforcement class has its own characteristic, with many data may be the same for different types or radically different. Their main parameters are listed below.
AI or A240 – the fittings representing a smooth-bore rod with cross-section from 6 to 40 mm. It is used in the manufacture of concrete products for the construction of monolithic and supporting structures. Armature of any diameter is produced in rods, packed in packages. Production with a cross section of up to 12 mm in coils is allowed.
AII or A300 is a profile with a corrugated surface and a diameter of from 10 to 80 mm. Belongs to materials holding strong pressure. They serve as the basis of the supporting structure, which is experiencing the main load. Used in the construction of low-rise buildings, monolithic buildings and during repairs.
AIII or A400, A500 – reinforcing bars with a periodic profile with a cross section of 6 to 40 mm. The most popular class of reinforcement of wide application both in housing construction, and in industrial or commercial. Also used in the production of concrete products, in the construction of roads and sidewalks. Products with a diameter of up to 10 mm are produced in hanks, over a given size – in rods.
АIV or А600 – rods with a diameter of 10-32 mm. They are used in the construction of stressed elements. The products are similar to the products of class АІІІ, but have a lower frequency of the ribs.
AV or A800 is a rare range of reinforcement with a high degree of strength. Used in the construction of especially large and super-heavy objects, such as bridges, moorings, subways, hydroelectric power stations.
A6 (A1000) – made from heat-resistant steel. It has an increased level of resistance to various types of deformation. It is used in high-rise construction.
Since the third category is the most common, what type of reinforcement (A400 or A500) to choose is up to designers who take into account all the nuances of construction work. Speaking about the structural features of this type, one should pay attention to GOST valves A500. It regulates the production of a round profile having two ribs along the rod and parallel rows of crescent shaped crests across. However, they do not intersect with paired ribs along the body of the rod.
The profile has high ductility and strength characteristics in the rolling process. The A500 bars of the reinforcement have a minimum length of 6 m, and the maximum length is 25 m. The optimum length of the rods is 12 m. According to the assortment table, the A500C fittings are made from high-quality marked steel St3SP, St3PS and St3GPS. The material has excellent weldability, but this is not its only advantage.
Helpful advice! It is possible to connect A500C reinforcement elements using electric arc welding machines. This advantage is indicated by the letter C in the profile marking. The quality of welding reduces the minimum presence of alloying elements.
The positive properties of such valves are as follows:
- increased degree of strength and flexibility, the absence of weak points that may lead to the destruction of reinforcement;
- relatively low cost of production and, as a result, affordable cost of reinforcement per ton;
- A500 reinforcement ratio implies significant savings in steel volumes during the manufacturing process.
GOST requirements: B500 fittings, features of its manufacture
Armature A500C successfully used in compressed elements. At the same time, the quality of concreting is enhanced by reducing the number of metal structures in the columns. Profiles can be used in projects where sections of classes АІ and АІІІ are indicated. Analogous to the universal reinforcement A500C can be B500 reinforcement.
The B500C armature in accordance with the chemical and technological characteristics of the raw materials and the structure conforms to European standards. The main advantage is flexibility. The high degree of plasticity of reinforcing structures prevents the destruction of buildings. Reinforcement products of this class in the Russian Federation are manufactured according to GOST R 52554. It is intended for the erection of structures made of lightweight and weighted concrete.
Such buildings are operated in aggressive environments. Armature is used both in the form of independent rods, and in frames and welded products. B500C according to the characteristics is an effective substitute for valves with A400, A400C, A240 markings. The B500C armature has the following basic parameters:
- produced in accordance with the standards of the European Union, which makes it possible to use on European equipment;
- does not curl due to the absence of stripes;
- it is extended by 1.4%, withstanding a load of more than 3%;
- characterized by excellent weldability.
As for pricing, it is different and depends on the characteristics of the valve and the volume of the required products.
The fact that the meter’s reinforcement meter costs is also influenced by the seasonality of the work, since any construction depends on weather conditions. Therefore, in the autumn-winter period, the price of rebar, as well as other types of building materials, drops significantly. It is this period that is considered the most optimal for the purchase of goods, but it should be worried about its appropriate storage.
Armature is an important material in modern capital construction. This type of metal has a number of serious quality characteristics and operational requirements, regulated by GOST. They are displayed in special tables and regulations, referred to as the range of valves. Knowledge of its main indicators and the ability to carry out correct calculations will help not only to purchase a quality product, but also significantly reduce the cost of its purchase.