Fittings GOST 5781-82: technical characteristics, application

In the manufacture of various kinds of reinforced concrete structures, metal fittings are mandatory. GOST 5781-82, the technical characteristics of this material regulate quite definitely. The reinforcement should be, first, strong, 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 there is no stretching. The main goal of the reinforcement is to prevent the destruction of structures with various kinds of movements.

Types of rods

It regulates the standards of such common building material as fittings, GOST 5781-82. Its technical characteristics can be different. The armature is classified as follows:

• AI - smooth round profile;

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

According to the method of manufacturing, the reinforcement can be:

• Hot-rolled (rod);

• Cold drawn (wire).

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

• Workers;

• Distribution;

• Assembly.

By the method of installation, the armature is welded or knitted.

Other classification

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

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

2. A500C. This kind of bars can have a periodic or circular profile. Depending on the quality used for the manufacture of steel, these bars are divided into different classes. The main purpose of A500C fittings is the creasing of conventional reinforced concrete products.

3. B500C. This type of rod is used mainly in monolithic construction, for the manufacture of embedded parts, as well as various types of strong hooks and curved profiles. From А500С the reinforcement of this group differs first of all in that it is not hot-rolled, but cold-deformed.

4. 25G2S. The main advantages of this type of rods are a high degree of strength, reliability and durability. Use this class of reinforcement in both the manufacture of secondary reinforced concrete structures and carriers. The corrugation of the rods of this brand has its own peculiarities and allows to carry out the most durable adhesion to concrete.

5. 35GS. This specialized fittings are made of the highest quality steel and can have both a round and rippled surface. It is used mainly in the construction of critical structures of reinforced concrete.

Valve assortment

Thus, precisely the quality and range of fittings of GOST 5781-82 is regulated. The table below shows the ratio of the cross-sectional area of the bars and their mass.

Below, you can see how the range of reinforcement, GOST 5781-82, is defined in terms of the relationship between diameter and weight. The table presents this more than graphically.

Classes of specialized fittings

Rods made from special steel grades are marked with letters so that the consumer can determine the specific area of their use. The class of reinforcement GOST 5781-82 in this case defines as follows:

• "T" - this marks corrosion resistant reinforcement, which can be used even in a humid climate;

• "C" - rods that can be welded;

• "B" - strengthened by the hood reinforcement.

Color marking

Actually the class of reinforcement can be determined and a little differently. To no one had any questions about the type of bars, they are marked at the ends with paint. Thus, AIV material is marked with red, AIII - yellow, AV and VI - blue. By standards it is allowed to paint rods on the ribs up to 0.5 m from their ends.

Main area of use

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

• Pouring foundations;

• Manufacturing of overlappings:

• Erection of bridges;

• Road construction;

• In masonry from gas and foam concrete blocks.

The smooth armature is used most often only to give the reinforced concrete product a certain shape. Ribbed is used for uniform load distribution. Before pouring concrete, the reinforcement is usually assembled into a strong frame. In this connection, both the welding and the special knitting wire can be used to join the elements.

Profile

Smoothly called reinforcement with an even matte surface along the entire length. Also the profile of the rods can be:

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

2. Sickle-shaped. Such fittings are usually produced by European manufacturers. However, there is also material of this variety manufactured at Russian plants.

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

Supply

On the warehouses of sales representatives, the steel armature (GOST 5781-82) with a diameter of up to 12 mm can come in coils or rods. Thicker rods are supplied only in rods. The length of the latter is usually 12 or 6 m. Sometimes the reinforcement can go in the non-dimensional lots. In this case, the length can start from 3 m. The bars should ideally be absolutely smooth. However, this does not always happen. A slight curvature, since the bars differ in relative flexibility, is allowed. However, within certain limits. According to the standards, the curvature should not be more than 6 mm per 1 p. M.

Armature GOST 5781-82: the price of the material

The cost of the rod depends primarily on its diameter. So, the price for a 10 mm armature can fluctuate within 20-25 thousand rubles per ton or 20-25 rubles. For running meter. The 12 mm corrugated rod most often used in the construction of residential buildings is about 22-29 thousand rubles.

So, we have found out what kind of building fittings can be. GOST 5781-82 specifies the technical characteristics of such rods precisely. The reinforcement must be made of the steel type corresponding to its brand and have a weight corresponding to the diameter.