GOST 5781-82 fittings: technical specifications, application

In the manufacture of various kinds of reinforced concrete structures , metal fittings are mandatory. GOST 5781-82 regulates the technical characteristics of this material quite definitely. The fittings must be, firstly, durable, and secondly, resistant to corrosion and durable.

This element allows you to build much more reliable foundations, floors and other similar structures. The fact is that concrete has a very high compressive strength, but tensile - not. The main task of reinforcement is to prevent the destruction of structures during various kinds of movements.

Types of Rods

Regulates the standards of such common building material as rebar, GOST 5781-82. Its technical characteristics may be different. Reinforcement is classified as follows:

• AI - smooth round profile;

• AII, AIII, A IV, AV and AVI - periodic corrugated profile.

By the method of manufacturing the fittings are:

• hot rolled (core);

• cold drawn (wire).

In addition to metal, fiberglass rods of this type are also produced in our time. According to the principle of operation, they also distinguish between tensioned and conventional reinforcement. In addition, there are several types of such rods, classified by purpose:

• workers;

• distribution;

• assembly.

According to the installation method, the reinforcement is welded or knitting.

Other classification

At the moment, there is a slightly different division of reinforcement into groups:

1. A1. The smooth fittings of this variety are made of high quality low alloy steel. Sometimes a rod of this brand is also made of cold-drawn wire. The main advantage of A1 fittings is that it can be used in absolutely any environment.

2. A500C. This type of bar may have a periodic or circular profile. Depending on the quality of steel used for the manufacture of steel, these rods are divided into different classes. The main purpose of A500C fittings is to fasten ordinary concrete products.

3. B500C. This type of rod is mainly used in monolithic construction, for the manufacture of embedded parts, as well as various kinds of durable hooks and bent profiles. The reinforcement of this group differs from 500 primarily in that it is not hot rolled, but cold-deformed.

4. 25G2S. The main advantages of bars of this type are a high degree of strength, reliability and durability. It is possible to use reinforcement of this class both in the manufacture of secondary reinforced concrete structures and in supporting structures. Corrugation of rods of this brand has its own characteristics and allows for the most durable adhesion to concrete.

5. 35GS. This specialized fittings are made of the highest quality steel and can have both round and corrugated surfaces. They use it mainly in the construction of critical structures made of reinforced concrete.

Range of fittings

Thus, it regulates exactly the quality and assortment of fittings GOST 5781-82. The table below illustrates the ratio of the cross-sectional area of ​​the rods and their mass.

Below you can see how the assortment of fittings GOST 5781-82 is determined in terms of the ratio between diameter and weight. The table presents this more than clearly.

Specialty classes

Bars made of special steel grades are marked with letters so that the consumer can determine the specific scope of their application. The reinforcement class GOST 5781-82 in this case is defined as follows:

• “T” - this is how corrosion-resistant reinforcement is labeled, which can be used even in humid climates;

• “C” - rods that can be welded;

• "B" - hardened hood.

Color marking

Actually, the class of reinforcement itself can be defined in a slightly different way. So that no one has any questions about the type of rods, they are marked at the ends with paint. So, AIV material is marked in red, AIII - yellow, AV and VI - blue. By standards, it is allowed to paint the rods on the ribs up to 0.5 m from their ends.

Primary Use

Thus, the manufacture of various kinds of reinforced concrete structures is what reinforcement can be used for. GOST 5781-82 determines the technical characteristics of this material, as we found out, in accuracy. Depending on the specific properties, such metal bars can be used for:

• foundation pouring;

• production of floors:

• construction of bridges;

• road construction;

• in masonry from gas and foam concrete blocks.

Smooth fittings are most often used only to give a reinforced concrete product a certain shape. Ribbed is used to evenly distribute the load. Before pouring concrete, the reinforcement is usually assembled in a strong frame. At the same time, both welding and a special knitting wire can be used to connect the elements.

Profile

Smooth is called reinforcement with a smooth matte surface along the entire length. Also, the bar profile is:

1. Periodic. Such material may have notches, ribs, protrusions. This allows you to increase adhesion to concrete.

2. Crescent. Such fittings are usually produced by European manufacturers. However, there is also material of this variety manufactured at Russian factories.

3. Mixed. This type of profile allows you to maximize the coupling of reinforcement with concrete. Therefore, rods of this type are usually used in structures subject to severe loads.

Supply

Steel fittings (GOST 5781-82) with a diameter of up to 12 mm can be delivered to the warehouses of sales representatives in coils or rods. Thicker rods are only available in rods. The length of the latter is usually 12 or 6 m. Sometimes reinforcement can go in unmeasured batches. In this case, the length can start from 3 m. The bars should ideally be absolutely even. However, this does not always happen. Slight curvature, since the rods are relatively flexible, is allowed. However, within certain limits. According to the standards, the curvature should not be more than 6 mm per 1 p.m.

GOST 5781-82 fittings: price of material

The cost of a bar depends primarily on its diameter. So, the price of rebar 10 mm can range from 20-25 thousand rubles per ton or 20-25 rubles. per linear meter. A 12 mm corrugated rod most often used in the construction of residential buildings costs about 22-29 thousand rubles.

So, we have figured out what construction reinforcement can be. GOST 5781-82 determines the technical characteristics of such rods precisely. The fittings must be made of the corresponding type of steel and have a weight corresponding to the diameter.