What kind of steel are the fittings made from?

Reinforcement for the foundation, which steel grade is better?

In private construction, many developers do not pay due attention to the creation of reinforcement for the foundation, believing that concrete is able to withstand loads. Also, inexperienced builders do not pay attention to the brand, type and class of reinforcement bars.

Foundation reinforcement is a necessary element of the components of the reinforced concrete foundation of a house. It allows you to increase the strength of the foundation of the house, since concrete alone does not cope well with the impact of the load. When pouring a concrete mixture, steel reinforcement bars in the concrete mass are positioned so that the main load falls on them.

Reinforcement for different types of foundations

In order for concrete strengthening to be realized to the maximum extent, you should know what reinforcement is needed for arranging a strip foundation, calculate it and carry out construction work correctly.

When choosing metal reinforcement bars, you must consider:

• view;
• Class;
• grade of steel from which the rods are made;
• cross-section of rods.

What reinforcement is needed to create a strong frame?

View

The reinforcement for the foundation is made of steel rods in the form of rods with a round cross-section. They can be smooth and profiled. To improve the strength of the foundation, rods with a ribbed surface are produced. They can be used for the foundation as the main material, and for auxiliary purposes it is better to take smooth rods.

Previously, only steel reinforcement was used, but now there are rods made of durable fiberglass that can be used in wetlands. Their main advantage over steel ones is their resistance to corrosion.

Types of profiles for reinforcement

Class

For a reinforced concrete monolithic slab, grooved rods of class A400 are required. Although they are more expensive than smooth ones, their grip is much higher.

Important! Do not choose reinforcement for foundation construction of lower classes than 400; if you wish, you can choose higher classes.

Brand

For the construction of the foundation of the house, hot-rolled steel reinforcement is used. The brands of reinforcement for strip foundations are designated by the letter “A”. The number 400 indicates the yield strength. The greater the load, the higher this figure should be.

How to choose the right materials for a bath? Pay attention to the markings. Rods marked with the letter “C” can be joined by welding. If it is marked “K”, it means that the material is not susceptible to corrosion.

Mechanical characteristics of hot-rolled fittings

Section

Section is the main parameter of the rods. Steel rods are produced from 0.5 to 3.2 m, metal-plastic rods can have a diameter from 0.4 to 2 cm.

When constructing private houses, rods with a diameter of 0.8-1.6 cm are needed.

How is reinforcement carried out?

When building a house on a concrete slab, it is necessary to reinforce the frame in the compression zones, these include the places where load-bearing and transverse walls or columns are supported.

Reinforcement of the foundation tape is carried out in the following order:

• create the axes of the metal frames of the tape;
• bend the rods so that the ends go in different directions. This is necessary to strengthen corners and junctions;
• connect the reinforcement of the strip foundation. The pins must be overlapped;
• To secure the top row of rods, transverse rods are installed on each reinforcing belt. The longitudinal lines are connected to each other with wire and then connected to the bottom row;
• install the upper rods and reinforce the corners at their intersections using bends in the form of clamps;
• connect the rods of the top row with support clamps to increase the rigidity of the frame;
• install plastic, metal or fiber-reinforced concrete clamps to hold the reinforcement in the center of the formwork;
• carry out formwork.

Reinforcement scheme

The strip foundation is pressed by forces from below when the soil begins to swell due to frost, as well as by the weight of the house from above. Therefore, steel belts are made at the top and bottom. If the strip foundation is deep, then there are already three reinforcement belts. If the tape height is more than 150 cm, vertical and transverse rods are installed. This technique allows you to make the foundation strong even on weak soils.

Columnar foundation made of bored piles

In recent years, the pile-column foundation has become popular in the construction of private houses; this method is more technologically advanced. On unstable soils, bored piles expanding from top to bottom sometimes become the only possible foundation for a house.

The construction of a bored foundation begins with marking the location of the piles. In order for them to withstand the tensile load, reinforcement of the concrete cannot be done without vertical reinforcement.

Metal blank for bored base

First, prepare the material. To strengthen the heel of the post, 4 rods are required. The length of the rods is about 2.4 m. Their ends are bent in the shape of the letter L.

To create a frame, several pieces of rods are fastened together using knitting wire to obtain a rigid metal structure with vertical rods at least 8 mm thick. It is immersed in the well during pouring. The metal frame should not touch the walls of the hole and the bottom of the well. Then formwork is carried out.

When filling it, the frame is periodically shaken. To make concrete adhere more easily to metal, everything must be thoroughly compacted to prevent air voids from forming.

Bar reinforcement weight calculation table

Nominal profile diameter	Weight, kg/m
50	15,410
45	12,480
40	9,870
36	7,990
32	6,310
28	4,830
25	3,850
22	2,980
20	2,470
18	2,000
16	1,580
14	1,210
12	0,888
10	0,617
8	0,395
6	0,222

How to calculate reinforcement for a foundation

Now, to arrange the foundation, it is not difficult to buy reinforcement and concrete and make formwork; the difficulties lie in calculating the amount of materials needed. The calculation of the quantity and cost of reinforcement for each type of foundation is determined individually.

It is necessary to comply with technological standards for the location of fittings

Counting rules are regulated by regulatory documents. Based on the requirements of SNiP 52-01-2003, the total sectional cross-section of reinforcement for the foundation can be 0.1% of the area of ​​the entire reinforced concrete structure in a given plane.

Important! The most important mistake when reinforcing a slab-type foundation or any other is incorrect calculations of the expected load on the foundation, or the absence thereof.

To avoid mistakes, it is necessary to obtain geodetic data for a specific area. It is also important to consider the ratio of the total area of ​​the diameter of the rods and the area of ​​the tape.

For the frame, it is necessary to calculate the amount of wire for knitting the strip foundation and select the required number of rods for the strip base. This can be done while simultaneously drawing up a diagram of their location.

The amount of materials is largely determined by the perimeter of the base, and also depends on the width of the foundation.

How to determine the number of rods for reinforcing a columnar foundation. To make a frame for a post ᴓ 20 cm and 200 cm deep, you will need 4 rods with a diameter of 1.2 cm. How to connect the rods? This will require wire. The rods are tied in 4 places in 5 cm increments using horizontal elements.

For one pole you will need:

• ribbed reinforcement with a diameter of 0.6 cm and a length of 880 cm, taking into account an allowance of 20 cm for attaching the grillage;
• smooth rods ᴓ 0.6 cm – 320 cm;
• wire for knitting the frame – 480 cm.

Multiply the results by the number of columns.

Correct calculations will allow you to create a solid foundation for your house.

The calculation also takes into account the amount of cement. For every square meter of concrete there is a different number of rods. According to building codes, for the construction of a general-purpose foundation, 1 ton of reinforcing elements is required for every 5 m² of concrete.

The calculation method is very complex and depends on many factors. Therefore, for an individual developer it is associated with certain risks. If you follow technological recommendations and advice from experienced builders, you can make a strong foundation for your house.

What kind of reinforcement is needed for the foundation updated: May 23, 2018 by: Artyom

Source: http://okbeton.ru/strojmaterialy/armatura-dlya-fundamenta.html

What kind of steel are the fittings made from?

Typically, the construction plan does not take into account the forces that are used to shrink the concrete, as well as the effect of temperature changes. Mounting construction reinforcement helps compensate for the consequences of these processes. Both working and installation reinforcement are produced in the form of metal frames or meshes, which are created by welding or knitting individual reinforcing rods.

Reinforcement structures are introduced into reinforced concrete elements by calculating the load that will act on them during and after the construction of the building. Depending on this, brands of building reinforcement are selected.

Steel reinforcement: GOST, size, purpose

At metal rolling plants, two technological processes for the production of building reinforcement are carried out. Thus, today there is a difference between hot-rolled rod and cold-drawn wire reinforcement.

Construction reinforcement is manufactured in various diameters for use in various construction purposes, which determines the form in which it goes on sale: in coils, rods or coils.

Construction steel reinforcement grade depends on the class of reinforcing elements produced and is an indispensable means of strengthening reinforced concrete structures.

general information

The process of manufacturing building reinforcement, as a rule, ends with its strengthening. It can be heat treated or cold drawn. In accordance with this, certain markings are applied to construction fittings. Construction reinforcement also differs in the shape and type of its profile.

According to the regulations, production is allowed from low-alloy carbon 3sp ps, st3 kp, st3 sp. These are structural steels of ordinary quality.

Reinforcing steel - types and characteristics

In industry they are used in load-bearing elements of welded and non-welded structures at positive temperatures; use in toxic environments is allowed. The advantages of use are that it can withstand greater loads than a profile marked A can cope with, and acts as a frame for highly stressed structures.

The chemical composition of the metal used is characterized by a high content of silicon - alloying elements. The main purpose is to reinforce critical structures, for example, bridges.

Reinforcing steel grade 25G2S has the best mechanical properties. A, A - made from steel grades 80С, 20ХГ2Ц, purchased exclusively for large-scale construction projects, as they have a high safety margin, and are expensive.

These are high-rise housing construction, bridges, tunnels, large industrial and chemical facilities. For production, exclusively innovative materials with special alloying components are used.

Main characteristics of steel reinforcement

For the manufacture of fittings, metals are used that are officially permitted by regulatory documents. When ordering products, pay attention to additional markings. The products are supplied by the official manufacturer and comply with GOST requirements. You can order any batches of profile pipes, angles, sheets at competitive prices. To leave a request, call the hotline number listed on the website.

Class A-II includes periodic profile rods with protrusions running along helical lines with the same approach on both sides of the rod. Class A-III includes bars with periodic profiles and projections.

Note During the period of mastering the production of reinforcement of class A-IV, rods are produced up to 18 mm inclusive and with a profile established for class A-III, with the ends painted with red paint.

The nominal diameters of round rods of smooth and periodic profile and reference values ​​are given in table.

Reinforcing steel with a diameter of less than 10 mm is supplied in coils, and with a diameter of 10 mm and more - in bars with a length of 6 to 12 m in the form of tied bundles weighing up to 5 g.

Construction encyclopedia. Section: Life. Typically, steel reinforcement is used that has high tensile strength; in some countries bamboo is used for this purpose; Research is being conducted to create fiberglass reinforcement. The reinforcement must work together with concrete at all stages of loading the structure, and have high strength and ductility.

Low-carbon cold-drawn wire reinforcement GOST -53 is produced with a diameter of 3; 3.5; 4; 4.5; 5; 5.5; 6; 7; 8; 9 and 10 mm in skeins and coils. The normal weight of a skein consisting of one piece should be 10-15 kg, and the minimum weight is 6-10 kg.

Reinforcing steel: grade, GOST, strength class. Steel fittings

The weight of a coil consisting of several skeins should be no more than 80 kg. Cold-flattened reinforcement of periodic profile GOST -52 is a round rod with dents located parallel to the longitudinal axis in two mutually perpendicular planes.

Today, the construction of any building or technical structure cannot be completed without the use of concrete mortar. The reinforced frame of the structure greatly increases the strength of the structure, preventing cracking and destruction of concrete buildings.

Modern rolled metal products offer various types of steel construction reinforcement for the formation of reinforced concrete structures for various purposes.

To absorb tension and strengthen compressed zones of concrete structures is the main purpose of construction reinforcement.

Category I includes reinforcement made of steel grade St. Cold-drawn carbon reinforcement of periodic profile GOST Wire is round steel with double-sided dents located parallel to the longitudinal axis, and is intended for reinforcing prestressed reinforced concrete structures.

Source: https://www.nauka-i-religia.ru/iz-kakoy-stali-delayut-armaturu.php

Reinforcement and its types

One of the most popular queries on the Internet on the topic of rolled metal is: “How many meters of reinforcement are in one ton.” We will answer it at the end of the article, but its topic is broader - metal reinforcement, its types, application and a little history.

Typically, the term “rebar” refers to flexible rods in the form of rods or welded mesh. Sometimes other types of rolled metal are “welded” to the reinforcement - I-beams, channels and angles, calling it rigid reinforcement. This type is used primarily in welded structures. But in our article, by the term “reinforcement” we will mean only flexible reinforcement, or more precisely, the proven reliable and popular steel rod reinforcement.

Reinforcement refers to rods of various shapes, cross-sections, metal strands and ropes that absorb part of the stress (tensile and shearing) that occurs in the product, which appears in reinforced concrete elements from the own weight of structures and external loads.

Another definition of reinforcement: elements that are not part of the main composition, but provide strength and efficient operation of the entire structure.

A little history

With the advent of concrete, construction became much easier. Before this, metal beams were also used, but in combination with clay (the first structures of this type were discovered on the island of Sicily, dating back to approximately 400 century BC). However, the adhesion of clay bricks and iron beams for reinforcement was not strong.

Moisture penetrated into the resulting cracks, the metal rusted and the buildings rapidly collapsed. The invention of concrete marked the beginning of the massive use of reinforcement: the adhesion of concrete and metal reinforcement turned out to be very strong. The combination of the opposite properties of cement and metal rods - compression and elongation - was also successful.

All this ensured the high popularity of concrete products in construction.

Types of fittings

Construction reinforcement is divided into types according to several indicators: 

• production material - metal (steel) and non-metal;
• appearance - rods, wire, rope;
• functions performed - prestressed (for floor slabs) and non-tensioned (for reinforced concrete panels, foundation);
• profile - smooth, periodic profile (various grooves), round (rounded rod, along the length of which two longitudinal ribs and transverse protrusions are applied, running in three passes along a helical line);
• purpose - installation, working, distribution and clamps;
• installation method - welded and knitted (frame, mesh);
• location in the reinforced concrete frame - longitudinal (partially takes on the load of the structure) and transverse (prevents cracks);
• manufacturing complexity - light (up to 12 mm in diameter), heavy (12-40 mm);
• physical and mechanical properties - hot-rolled, thermomechanically hardened in the flow of mills, mechanically hardened in a cold state.

Smooth and corrugated reinforcement

The main characteristics that immediately catch your eye are the presence or absence of corrugation. To the question: “is smooth or corrugated reinforcement better?” - there is no definite answer. They are simply different and are used according to their properties.

The smooth profile is marked as A1, and the periodic profile is A2, A3, A4, A5 and A6. The most popular are products A1 and A3. Smooth fittings are mainly produced with a diameter of 6-40 mm. The thinnest is wire.

Profiles of medium and large thickness are produced in measured and unmeasured rods.

Products of class A1 are made from steel grade with a significant yield strength. Smooth reinforcement bends and welds well. It does not “adhere” to concrete as well as corrugated concrete, but has better fluidity. This is a universal fitting that people like to use in extreme weather conditions, when A3 class products can crack (due to the lower “fluidity” of the material). Also, smooth profiles are used as blanks in the production of hardware, bolts, etc.

Transverse and longitudinal grooves, evenly spaced along the entire length of the rod, perfectly adhere concrete to reinforcement. Due to this, it is used as the main reinforcing element of reinforced concrete products.

For the manufacture of class A3 products, high-alloy steel with admixtures of silicon, titanium, chromium, manganese, etc. is used. This makes the reinforcement resistant to physical stress.

Corrugated reinforcement is used where such strength is especially necessary: ​​floors, ceilings, high-rise structures, overpasses, bridges.

According to the types of corrugation, fittings are distinguished:

• ring,
• sickle-shaped
• mixed (experimental).

Steel for reinforcement

Although fittings are made from different metals, most often they are made of steel. Steel has sufficient strength and excellent elongation. Both of these properties are important for creating reliable reinforced concrete products.

Proper quality reinforcing steel has a good combination of “yield” and “tensile strength.” To achieve the best quality of steel, the chemical composition of the metal and the method of manufacturing rods or wire are adjusted.

For better weldability, a composition with a reduced carbon content is selected.

Reinforcement mesh

For large-scale construction, reinforcing mesh is used. The reinforcement bars are welded or knitted immediately before pouring concrete and the finished mesh is rarely transported. Products made of special steel are used for welding.

Or use a special welding wire. The disadvantages of welding include increased fragility of the product in the welded area and poor response to bending. The bonded frame is stronger and more flexible.

If, of course, the mating conditions are met and high-quality wire is used.

GOST for fittings

In conclusion, let’s add a little about the standards for the manufacture of fittings. There are a lot of them. Let's name the main ones:

• Steel rod reinforcement - GOST 5781-82.
• Thermomechanically strengthened reinforcement - GOST 10884-94.

Manufacturing plants often produce products based on their own specifications. Metal products made not according to state standards, but according to technical conditions, are no worse. Different problems require different ways to solve them. By producing products according to their own specifications, most factories strive for unification, focusing on STO ASChM 7-93 “Rolling of periodic profiles from reinforcing steel.”

It is not necessary to know the standards for the fittings you buy, just as there is no need to rely only on them in search of quality products. It is more important to know the quality indicators of products and trust the seller (manufacturer) from whom you buy.

When purchasing reinforcement, it will be necessary to convert linear meters into tons, since the price is most often indicated per ton of material. How many meters in one ton will depend on the diameter of the rods: the thinner they are, the more meters will fit in one ton.

A special rolled metal calculator or a table for calculating reinforcement will help you convert meters of reinforcement into tons.

Let's take, for example, the most popular reinforcement with a diameter of 12 mm: one linear meter will weigh 0.888 kg, and a ton of reinforcement will contain 1126.13 linear meters.

You can view the range and prices of reinforcement and welded mesh in the online store.

Source: https://www.1metallobaza.ru/blog/armatura-stalnaya-chto-nuzhno-znat-o-ney

Types of steel reinforcement

By production method:

• Hot rolled - obtained from a preheated billet by rolling. This reinforcement is characterized by increased flexibility and large rod diameters (from 3 to 80 mm). It is produced in accordance with GOST 5781-82. The tensile strength class is designated here by the letter “A”, for example, A300 (A-II) and A400 (A-III).

• Cold-formed - made with a diameter of 3 to 5 mm by drawing rolled rods through a system of successively smaller holes. The peculiarity of such reinforcement is that it has increased tensile strength and reduced flexibility. The main standard here is GOST 6727-80. It is designated in the same way as the previous fittings, only instead of the letter “A” the letter B is placed. Example: B500 (Вр-I) or B500С.

• Thermomechanically strengthened - reinforcement obtained by plastic deformation and heat treatment. In terms of its properties, it is something between hot-rolled and cold-deformed reinforcement. In other words, such reinforcement has increased flexibility and at the same time quite high strength. The main standard for it is GOST 10884-94, according to which the diameter of the rods here can be 6-40 mm. As for the strength class, it is designated by the letters “At”, which are placed before the numbers indicating the yield strength in MPa. It is also not uncommon to see the indices “C” and “K” after the number, which “speak” of good weldability of elements or resistance to corrosion cracking, respectively. Designation examples: At400S, At600K.

By profile:

• Smooth - reinforcement that has a constant cross-section along its entire length.

• Periodic profile - reinforcement with uniform corrugation for better adhesion to concrete.

By method of secondary exposure:

• Tensile reinforcement is reinforcement that is stretched before being concreted. Usually uses jacks or electric current for this. It is produced only as part of finished reinforced concrete products that require increased load-bearing capacity.

• Non-tensioned - reinforcement that is sold in separate rods. It is from this that monolithic structures are erected on the construction site.

Scope and price

The table shows the most commonly used reinforcement bars for private construction.

Mode of production	Strength class	Profile view	Scope and price for 2016
Hot rolled	A240	Smooth	Clamps that protect the working reinforcement from compression. As an anchor element in an embedded part, but only in case of bending the end of the reinforcing bar. Price - from 19,000 rubles/t.
A400, A500, A600	Grooved	Working reinforcement for mesh foundation slabs, floor slabs, as well as longitudinal and transverse reinforcement for frames in reinforced concrete beams and monolithic strip foundations. Price - from 19,000 rubles/t.
Cold-formed	B500	Smooth and grooved	Mesh for reinforcing masonry made of bricks and blocks. Price - from 25,000 rubles/t.
Thermomechanically hardened	At800	Smooth	Elements of embedded parts where increased strength is required. Price - from 29,000 rubles/t.
At400, At500, At600	Grooved	Working reinforcement in meshes and frames, where the use of a certain diameter of reinforcement is required, and it is not possible to use class “A” reinforcement. As working reinforcement in heavily loaded reinforced concrete products. Price - from 25,000 rubles/t.

Advantages and disadvantages

Pros (+):

• time-tested - standards for steel reinforcement have long been developed according to which they are produced. Also, the regulatory documents (SP and SNiP for reinforced concrete structures) indicate steel reinforcement, i.e. all formulas and calculations are made specifically for such reinforcement;

• large range of diameters - this fittings can be produced with diameters from 3 to 80 mm;

• predictable and relatively long service life - steel reinforcement under normal conditions (in the absence of an aggressive environment and contact with water) can last 50 years or more;

• works well in bending - steel reinforcement has a modulus of elasticity 4 times greater than fiberglass reinforcement. This means that it can withstand bending load so many times more;

• accessibility - this building material is very easy to find and buy;

• the ability to choose the installation method - reinforcing bars can be either welded together or tied with wire;

• environmental friendliness - zero impact of the material on the human body;

• simplicity of the anchoring device - steel reinforcement can be bent by 90° in any place when heated with a burner. This circumstance makes it possible to produce bent elements required for anchoring reinforcement directly on the construction site;

• good adhesion to concrete - the “tandem” of steel and concrete works well throughout the entire life of the structure. This is largely facilitated by the almost equal coefficients of linear expansion of both materials (according to the reference book of the designer V. Blasi, for concrete it is equal to 0.000010 m/m°C, and for reinforcement - 0.000012 m/m°C);

• frost resistance - steel reinforcement does not change its properties at subzero temperatures.

Minuses (-):

• limited length - steel reinforcement is produced with a maximum length of 11.7 m (in very rare cases 12 m);

• heavy weight - to transport the material to the construction site, you need to hire special transport;

• poor corrosion resistance - steel, when exposed to oxygen, water and (or) an aggressive environment, corrodes at a rate of 0.1-0.5 mm/year;

• special storage requirements - such material is not recommended to be stored for a long time in the open air and without pallets, as the material will quickly become covered with rust.

Related calculators:

• calculation of reinforcement along the length;
• calculation of reinforcement mesh.

Other types of fittings:

article with friends:

Source: https://steelfactoryrus.com/iz-kakoy-stali-delayut-armaturu/

Classes and grades of reinforcement steel

06.06.2019

Reinforcement is used to improve the performance of concrete. It gives an increase in strength and allows you to withstand heavy loads without cracking or crumbling. Without the use of a frame made of metal rods or wire mesh, it would be impossible to construct concrete supports, bridges, underground structures and other structures.

According to purpose, reinforcement is divided into four types:

• Anchor . Used to create embedded elements in concreting.
• Constructive . Eliminates deformation of the structure and distributes loads. Thanks to this, the concrete does not settle and thermal expansion is compensated.
• Working . It is necessary to take the main load and increase strength.
• Assembly . It is used when you need to connect disparate parts into a single frame.

Product characteristics indicate where it can be used. We sell prestressed and non-prestressed reinforcement, adapted for installation in supporting and unloaded structures.

According to the installation method, longitudinal and transverse varieties are selected. The first type resists vertical cracks well, the second - inclined ones.

Classes of fittings and areas of their use

On sale you will find rods that vary in diameter, length and surface type. There are smooth and grooved varieties. For ease of designation, they were divided into classes, for each the area of ​​use and a set of characteristics, as well as the steel grade of the reinforcement, were specified.

There are the following types:

• A1 (A240, AI). One of the most common types of materials for the manufacture of reinforced concrete products is trays, floor slabs, and support elements. The diameter ranges from 6 to 40 mm. Depending on this parameter, the product is supplied in skeins or rods.
• A2 (A300, AII). The diameter reaches 80 mm. Can be used as a frame for piles. Installation in concrete increases its resistance to vertical loads.
• A3 (A 400, A III ). There are ribs on the surface of the rod. Corrugation improves adhesion to concrete. Diameter up to 40 mm. Products up to 10 mm are supplied in skeins, larger quantities in rods.
• A4 (A600, AIV). Metal elements are used as the basis for reinforced concrete products for various purposes. They are suitable for the production of parts subject to dynamic loads. It is also widely used in construction – not only civil, but also industrial.
• A5 (A800, AV). The material is created from structural low-alloy steel. The recommended area of ​​application is the creation of prestressed concrete products. Suitable for the construction of bridges and hydraulic structures.
• A6 (A1000, AVI). The characteristics allow the use of steel rods in the most critical areas - from nuclear industry facilities to dams. Since the product is expensive, it is produced upon pre-order. Provides good adhesion to concrete due to the special structure of the ribs - they are ring-shaped or crescent-shaped. Can also be used with reinforced concrete products. Reinforcement significantly extends their service life.
• A400C . Manufactured using the hot-rolled method. The diameter reaches 40 mm. It is distinguished by the presence of two ribs located longitudinally. Used in private construction, in the construction of low structures.
• A500C . Additionally strengthened by mechanical and thermal methods. Not adapted to strong dynamic loads, used with basic types of reinforced concrete products.
• A600C . It is characterized by increased resistance to corrosion due to the addition of molybdenum and vanadium to the alloy. Suitable for monolithic houses, construction in areas with high seismic activity.

Below is a table of classes and brands of fittings with the main characteristics listed.

Reinforcement class	Rolled diameter	steel grade	Mechanical properties, no less
σ T , N/mm2 yield strength	σ B , N/mm2 tensile strength	σ S , % relative. elongation	Cold bending test, C – mandrel diameter, B – rod diameter
A-I (A 240)	6-40	St3kp, St3ps, St3sp	235	373	25	180 deg C=d
A-II (A 300)	10-40	St5sp, St5ps	295	490	19	180 deg C=3d
40-80	18G2S
AC-II (AC 300)	10-32	10GT	295	441	25	180 deg C=d
A-III (A 400)	6-40	35GS, 25G2S	390	590	14	90 deg C=3d
6-22	32G2Rps
A-IV (A 600)	10-18	80C	590	883	6	45 degrees C=5d
10-32	20ХГ2Ц, 20ХГ2Т
А-V (А 800)	10-32	23Х2Г2Т, 23Х2Г2Ц	785	1030	7	45 degrees C=5d
A-VI (A1000)	10-22	22Kh2G2AYu, 22Kh2G2R, 20Kh2G2SR	980	1230	6	45 degrees C=5d

Steel grades for the production of fittings

The grade classification and classes of reinforcing steel indicate the performance characteristics. Among the most common varieties:

• 20GS . Structural low alloy steel. It lends itself well to welding, therefore it is suitable for the manufacture of reinforcing frames.
• 35GS . Another structural low-alloy variety. Well protected from aggressive environments and pressure.
• St3kp . Structural carbon of ordinary quality. Shows good adhesion to concrete and does not deteriorate due to pressure, vibration, or exposure to aggressive environments.
• 22Х2Г2АУ . The characteristics of this low-alloy structural steel make it suitable for use in both conventional and prestressed concrete structures.
• 80C . Durable material that can withstand high stress and aggressive environmental influences.

The table below shows the correspondence of the class of reinforcing steel, the grade of raw materials used in the manufacture and the profile diameter of the created rod.

Table of reinforcement classes and steel grades - steel for reinforcement according to GOST 5781-82

Profile type	Class	Diameter, mm	steel grade
Smooth profile	A1 (A240)	6-40	St3kp, St3ps, St3sp
Periodic profile	A2 (A300)	10-40, 40-80	St5sp, St5ps, 18G2S
Periodic profile	A3 (A400)	6-40, 6-22	35GS, 25G2S, 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)	23Х2Г2Т
Periodic profile	A6 (A1000)	10-22	22Х2Г2АУ, 22Х2Г2Р

What determines the scope of application of fittings?

Several factors influence where a particular type of rod will be used:

• Degree of workload.
• Potential threats.
• Scope of application of reinforced concrete products or location of the reinforced building.

Before you buy a batch of steel rods, you need to understand what the loads acting on them will be - static or dynamic. The mechanical parameters of the future frame are also taken into account. If you need to connect several parts by welding, the steel must have a good level of weldability.

Source: https://spbrmk.ru/klassy-i-marki-stali-armatury/

Methods of production of fittings

Like many other metallurgical products, rod reinforcement is made by hot rolling. The workpiece is heated to a high temperature and driven through numerous rotating rolls. If you need to get corrugations on the surface, then they are also made using rollers, only of a special shape, with a corresponding profile on the surface.

Since high surface quality for reinforcement is not required, but rather productivity is primarily important, hot rolling is ideal for the production of these products. To ensure strength properties, reinforcement of class A800 and higher is subjected to low-temperature tempering.

Wire reinforcement is made by drawing. This method involves pulling the workpiece through a hole slightly smaller in diameter than the diameter of the workpiece.

In this way, it is impossible to greatly change the diameter of the product at one time, so this operation is performed repeatedly, using for each subsequent matrix with a smaller hole.

In general, drawing is a fairly effective production method, but it cannot produce products with a diameter of more than 25 mm due to significant loads on the tool.

Rebar of class A300 and below with a diameter of up to 12 mm and A400 with a diameter of up to 10 mm is wound into skeins. Higher-class fittings are produced only in the form of rods; production in the form of coils is carried out exclusively in agreement with the customer. Heat-treated reinforcement can be rolled into coils with a diameter of up to 8 and product class up to At600C.

Materials for the production of fittings

Most reinforcement cages are produced by welding, so the material is required to have good weldability. Another important parameter is tensile strength.

Reinforcement of different classes is made from different grades of steel. For the least durable class A240, the simplest structural steels are used - StZkp, StZps, StZsp. The price of such material is also minimal.

For products of class A300, both conventional steels St5sp, St5ps, and alloy steel 18G2S, to which manganese and silicon impart increased performance properties, can be used. Products of higher classes are produced only from alloy steel.

As alloying elements, in addition to those mentioned above, chromium, titanium, aluminum, etc. are used. The choice of alloying elements was largely made so as not to reduce the weldability of products.

Most rebar has low carbon content. It is limited to 0.32 – 0.35%. This is true for conventional and thermomechanically strengthened reinforcement, with the exception of products with a diameter of up to 18 mm class A600, which are made of 80C steel with a carbon content of 0.8%.

Among the substances that negatively affect the properties of the material, sulfur and phosphorus are primarily distinguished. Their content in reinforcing steel should not exceed 0.045%, maximum deviation +0.005%.

Use of fittings

Reinforcement is used to create reinforced concrete elements of buildings. When reinforcing, the specifics of materials should be taken into account.

Concrete has a fairly high compressive strength, but when working in tension it quickly fails. Concrete tolerates bending loads moderately.

Therefore, reinforcement is primarily intended to withstand tensile loads. It also protects concrete elements from surface crumbling.

Most of the reinforcement has a corrugated surface, due to which its adhesion to concrete is significantly improved. In the rubble of destroyed buildings, you can often see that the concrete partially remained on the reinforcement, which is an excellent indication of the strength of the connection.

Prestressed reinforced concrete structures have very high strength. To create them, the ends of the reinforcing bars are clamped and stretched. After this, concrete is poured into the mold.

Relieving stress from the rods is carried out only after the concrete has completely hardened.

The rods exert a compressive effect on concrete, due to which the strength of such a reinforced concrete element increases significantly.

The article is for informational purposes only.
Don't forget to consult with experts.

Source: https://betfundament.com/iz-kakoy-stali-delayut-armaturu/

A500C fittings: technical characteristics and differences from A-III fittings

One of the most popular types of fittings today is A500C. The material is a rod of grade A5 with a diameter of 6 to 40 mm. This type of rolled product is produced in accordance with the requirements of GOST 52544 2006. The material refers to structural elements that are subjected to thermomechanical processing during the rolling process.

A500C fittings are considered universal due to their excellent performance characteristics. The low carbon content of steel and its thermomechanical treatment during the production of rolled products ensure ductility and improved weldability of the final product.

The material is also characterized by increased durability and viscosity. In terms of its properties, fittings of this class meet the requirements of international standards.

The Gosstroy of Russia recommends the use of A500S grade in reinforced concrete structures instead of and along with At-IIIS (GOST 10884-81) and A-III grades 35GS and 25G2S (GOST 5781-82) reinforcement of the same diameter.

Explanation of markings

The letter A in the marking indicates that this type of material belongs to hot-rolled steel and is thermally and mechanically reinforced. The letter C indicates the possibility of using welding to connect elements. The number 500 in the marking indicates the yield strength of the material.

Delivery form

Rolled products of class A500C are supplied in two forms: in the form of coils or rods. If the cross-sectional diameter is up to 6 mm, the material is formed into coils, from 6 to 12 mm it is supplied in coils or rods at the request of the client. If the diameter is more than 12 mm, rolled products are sold only in the form of rods.

Production

Fittings of this class are produced under the control of GOST R 52544-2006 and STO-ASChM 7-93. Low-carbon steel grades 35G2S and 35GS are used as the manufacturing material. carbon is no more than 0.22%. For the production of A500C, two methods are used: cold drawn and hot rolled.

In the first case, wire and rolled reinforcement is created, in the second - rod reinforcement. It should be noted that rolled products of the second type are characterized by higher strength. The raw materials for A500C contain fewer alloying components than analogues, which ensures a more favorable cost of the final product.

Application

A500S reinforcement is widely used in the construction industry when creating reinforced concrete structures, pouring foundations, etc. The material is used to reinforce or strengthen load-bearing structures (in accordance with GOST 10884-94) or simple reinforced concrete structures (in accordance with GOST 5781-81).

Advantages

The A500C has many advantages, we will list the main ones:

• increased design resistance to loads, which provides a quantitative reduction in the consumption of reinforcement for creating structures;
• profitability due to the low cost of thermomechanical processing of the material;
• increased strength and ductility due to the absence of hardening in the welding zone;
• unification - that is, the possibility of replacing fittings of classes A240, A300 and A400.

Difference between A500C and A-III

The type of reinforcement that will be used in the construction of a new building is selected at the project development stage. For residential buildings weighing up to 80 tons, A3 rolled steel is mainly used. This category includes fittings A400 and A500C. These classes are often considered the same or very similar, but they have significant differences:

• Scope of application. Both classes are used for repair and finishing, construction, production of reinforced concrete products, creating frames, etc. The difference between A500C and A3 (A400) is that the first class can be used in both loaded and unloaded structures, and the second - in areas of high stress.
• Appearance. Rolled products of class A500C have a profile with crescent-shaped protrusions that do not intersect with the longitudinal ribs. This shape provides higher plastic and strength characteristics. Also, thanks to the profile, the material does not have stress concentrators at the intersections of longitudinal and transverse ribs. Different manufacturers offer different versions of this material, which may differ in the angle of inclination of the crescent-shaped elements in relation to each other and the distance between them.
• Welding capability. A3 reinforcement, produced by the hot-rolled method from high-carbon type 25GS steel, complies with GOST 5781-82. The fluidity index of the product is 400 N/mm2, which is specified in the A400 marking. This material cannot be welded. To connect individual elements, only knitting wire can be used (as fastenings at seams).

We have collected all the main characteristics by which these two classes of rolled metal can be compared in the table below:

Rolled products of class A400 (A-III) can be replaced with A500C without re-calculating the project. Reverse replacement is allowed only in case of additional recalculations. This provides a significant increase in the strength and reliability of the structure, and also increases its service life. By choosing A500C class rental, you can reduce the amount of required material by an average of 10%. Reducing the volume of working reinforcement allows you to reduce the final cost of the project.

Source: https://www.stroymetall.ru/stati/osobennosti-armatury-a500s/

A500S fittings: steel grade and quality determination

A500S fittings are one of the most popular types of fittings today. These are special A5 brand rods, whose diameter ranges from 6 to 40 millimeters. When producing this type of material, the requirements of GOST number 52544 2006 are observed. These are structural elements that are subjected to heat treatment during the production of such a part as A500C reinforcement; we will consider what this is further .

Basic information and terms

The main material is steel, with a carbon content of 22%. Thanks to this number of initial components, the strength characteristics of the final product are improved. Production costs, as well as raw material consumption, are significantly reduced. Fastening between the joints is organized using arc welding.

The scope of application is quite wide:

1. For frame connections, when reinforced concrete products are produced.
2. For private construction, in the case of monolithic concreting.

The use of the material in practice involves the participation of bending machines.

Such products can withstand tensile loads, this is a positive characteristic. This promotes the use of products for structures with prestressing and thin walls. A universal type of material, one of the most popular. This is the A500 C reinforcement, the steel grade for which is carefully selected.

What features does the fittings have?

Marking with letters and numbers A3 is considered obsolete. A more correct designation for rental is A400. But often in practice the old version is used. GOST 5781-82 regulates technical conditions with basic characteristics. The varieties of carbon steel used in production have their own designations - 25G2S and 35GS. The difference between A300 and A400 in the main parameters leads to a decrease in ductility and an increase in the fragility of welded joints.

The demand for A3 is more than logical, taking into account the following points:

• High strength.
• Using knitting wire or clamps to connect frames.

Areas with high stress also do not exclude the possibility of using such types of reinforcement. They purchase reinforcement for the construction of various types of structures:

1. Pillars.
2. Columns.
3. Supports.
4. Foundations.

A3 and A500C: the difference between classes

The model range includes corrugated rods, whose diameter ranges from 6 to 40 millimeters. The total length will be up to 11.7 meters. Both varieties represent a group of hot-rolled products. Profile A3 has the following features:

• Ring appearance.
• Along the perimeter, the ribs are located more often.
• The design is characterized by the intersection of transverse protrusions and two longitudinal ones.

The rod and concrete form better joints with such adhesion. This contributes to the operation of products for monolithic structures made of reinforced concrete. For welding work, the most convenient will be the sickle-shaped A500C, characterized by sparser protrusions.

The first letter in the marking is needed to indicate the manufacturing technology and type of product. The letter A is used for heat-strengthened, hot-rolled products.

The following numbers characterize the type of steel that was used for production. If the rolled product has special properties, use another letter at the end.

1. C - this means that the rods require the use of electric arc welding.
2. K show high resistance to corrosion.
3. T says thermomechanical strengthening was applied to the steel.

Often, additional numbers are included in the marking to indicate the specific diameter of the A500C fittings, for which GOST is installed separately.

About the cost

The cross-section and mass remain almost the same for all types of such reinforcement. Only the manufacturer's markings and the specific profile lead to some differences in appearance. The prices themselves are determined by several parameters:

• Delivery terms.
• Batch volume. The larger it is, the more profitable the purchase will be.
• Seasonality. The summer season contributes to an increase in operating costs.
• Demand for a certain diameter, 12 millimeters remains the most popular size. This is important when choosing A500C fittings; what class - A1 or A3 - is decided by the buyer.

The difference in price also depends on the content of alloying components. The fewer there are, the cheaper the product costs. With a cross section of up to 6 millimeters in diameter, the product sales form is coils. But in most cases they sell cutting rods up to 12 meters long. Without proper recalculation, it is not recommended to simply replace A3 with A500 C. At the same time, the welded type of material is considered more universal.

Recommended reading:

Which foundation reinforcement to choose: types of material and calculation of the required quantity

Simple and proven methods of tying reinforcement for the foundation of a house

Additional benefits of using reinforcement

Permission for welding using electric arc devices is the main advantage that the 500 C fittings have. This possibility is indicated by the last letter in the marking.

A small amount of alloying components also helps to improve weldability. On average, modern technologies contribute to savings of more than 10% in production. Moreover, when compared with other existing classes. With a mandrel diameter, the bending angle can reach up to 180 degrees for A500C reinforcement, the price per ton for which also depends on this.

The fittings also have other distinctive characteristics that you should familiarize yourself with in advance:

1. Low cost production.
2. Production of products with savings in steel volumes.
3. Increased strength and ductility. There are no fragile places leading to the destruction of the entire structure.

The relevance of reinforcement increases for compressed elements. The saturation of columns with metal elements is reduced, and therefore there is less likelihood of corrosion. This type of fittings can be used instead of similar diameters A1 and A3. In the manufacture of critical structures, the material is used due to thermal, thermotechnical hardening.

Operation in Russia and main features

In Russia, this material was not only released for the first time, but also new standards were drawn up regulating the specifics of production. During the production process, samples are selected from each bundle of rods for which separate tests are carried out.

Because of this, production costs increase to some extent. But the percentage of misgrading is lower as a result. The result is high-quality A500C fittings; which class to choose is up to the customers to decide.

But when determining the fluidity of products, it is still almost impossible to avoid mistakes. Therefore, a special profile was developed, designated A500SP. Thanks to the use of this profile, it becomes easy to determine which class the reinforcement belongs to. Adhesion to the concrete mixture also improves during practical use.

The grip with the new profile is 20% better. The rigidity of the reinforcement increases by 30%. The limit of insertion of rods into profiles becomes larger.

Technological recommendations are described in a special document developed separately for fittings of this type.

During perestroika, the amount of reinforcement produced in coils decreased significantly. The production of diameters 6 and 8 millimeters has practically reached zero. Production capacities were freed up, which were then converted to create wire rods.

The following methods are used for so-called anchoring. If necessary, you can combine methods with each other:

• The end of the rod, supplemented with special devices.
• Additional rods, mounted or welded.
• A claw or hook placed at the end of a rod.
• Carrying out direct anchoring with a straight rod.

It is not recommended to bend the bars at the end when it comes to using compressed reinforcement.

Depending on the diameter of the reinforcement, the length of the anchorage can be reduced. The way the procedure is performed also influences the decisions that the masters make.

A500S reinforcement – ​​knitting technology

To create a frame, use regular wire or clamps. In the latter case, owners have the following advantages:

1. A simple mechanism for creating connections.
2. Quality.
3. Strength.

Flexibility and ease of use are characteristic of steel wires, in the manufacture of which low-carbon steel is used. The method of surface treatment is determined by the color design of the products. The white color suggests that zinc was used. Black confirms the absence of any additional types of processing.

1.2-1.4 millimeters is the recommended diameter of the wire used. Then strength and reliability remain at a sufficient level.

Tie wire is cheaper than PVC clamps. But plastic elements also have additional advantages:

• Connections made as easy as possible to create.
• High speed of work.
• Strength indicator.

The original geometry indicators are preserved even if the load is maximum. Of the negative aspects, there is only weak protection against the effects of negative aspects. If you leave such a frame in the cold, the clamps will break or the elasticity will decrease.

An acceptable option is plastic clamps with steel cores. This option can often be seen inside cable pipelines and pipes with low-current networks.

Knitting reinforcement with a hook is usually performed in four common ways. The main differences lie in the reliability of elements and connections, and the speed of creating frames. The use of special guns reduces the speed of construction of any structures. The economic effect will also be positive with this decision.

The reinforcement is knitted at the same time as the foundation is created. Thanks to this approach, the structure is strong and rigid, quite reliable. The use of welded joints is abandoned; they do not tolerate increased loads well. When choosing a welding method, you need to evaluate all factors, positive and negative sides.

Welding is the most popular method for those who want to connect any elements into a frame. After all, the material itself is highly weldable. Only in some cases welding will not be as rational a solution as knitting.

If the reinforcement has a diameter of 16 millimeters or more, then welding is allowed without fear of changing the original characteristics. At 10-14 millimeters, this option is also acceptable, but only if there are no seismic loads in the area. Otherwise, the plates will begin to move, which leads to the destruction of the entire structure.

The A500C fittings have a wide range that can be selected for almost any situation. But complex engineering and geological conditions and high loads impose some restrictions on the use of welded joints. Welding is used for buildings with a small amount of shrinkage. The situation is associated with the absence of dynamic oscillations.

Economic efficiency reaches its maximum in the case of large volumes of work. High-rise monolithic structures are often equipped with frames manufactured at specialized enterprises. This helps to reduce the costs of construction itself, and the costs of further work are also reduced. For welding, frames with meshes are assembled at the construction site if the amount of work is small. The solution is based on the customer with his current needs.

conclusions

A500S fittings are the most modern development in the direction of fittings. This class of products differs from others when it comes to the visual component. The structure has no longitudinal ribs; it is complemented by three profiles or a large number of them.

If cold forming is used for steel, then the advantage is the use for the production of welded mesh with the absence of scale. In this case, conventional welding with electrodes for connection is prohibited.

But even the susceptibility to corrosion can be easily circumvented if you choose the material and construct the structure wisely.

Source: http://blog.kpmtrade.ru/sortovoj-prokat/armatura-a500s/

Steel (Metal) reinforcement

Steel rod reinforcement is widely used in construction. This is an integral element of reinforced concrete structures, increasing the flexural and compressive strength of cement stone. We will tell you what metal fittings are, what they are made from, what classes they are divided into and the features of their use.

Rebar manufacturing technologies

According to the production method, the fittings are:

• Hot rolled rod;
• Cold drawn wire.

In both cases, low-alloy or carbon steel of different grades is used, depending on this, it is divided into 6 classes A-IA-VI.

The hot production method involves forming a softened steel rod blank using rollers. As the temperature increases, the bonds of the metal structure are strengthened; accordingly, reinforcement made from it is able to withstand greater loads compared to cold-drawn products, and the tensile strength increases.

Cold drawn reinforcement is obtained from an unheated workpiece passing through crimping rollers.

To increase the strength of the reinforcement, it is subjected to heat treatment or galvanizing - the procedure ensures the resistance of the metal to moisture and aggressive environments.

Rod reinforcement with a cross-section of 8 mm or more is produced in individual rods, thin wire reinforcement is produced in coils.

Classification and marking of fittings

The classification of reinforcement involves dividing products according to the class of steel used for the production of rods. The division is regulated by GOST 5781-82 “Hot-rolled steel for reinforcement of reinforced concrete structures”:

Class, old designationClass, new designationProfile typeColor designation of rod

A.I.	A240	Smooth	—
A-II	A300	Periodic*
A-III	A400
A-IV	A600	Red
AV	A800	Red and green
A-VI	A1000	Red and blue

*by agreement with the customer, A-IIA-V steel can be manufactured with a smooth profile.

Classes, in turn, are divided into subclasses, which are designated by additional indices:

• “C” is a rod steel that is suitable for welding;
• “T” - heat-treated product;
• “K” - corrosion-resistant steel, i.e. treated with zinc;
• "SK" is a corrosion-resistant steel that can be welded.

Metal fittings of different classes are made from various steel alloys, which determine its technical properties. In this case, the diameter of the rods is taken into account:

Reinforcing steel class Steel grade Profile diameter, mm

A-I (A240)	StZkp, StZps, StZsp	640
A-II (A300)	St5sp, St5ps 18G2S	1040 4080
Ac-II (Ac300)	10GT	1032 (3640)
A-III (A400)	35GS, 25G2S 32G2Rps	640 622
A-IV (A600)	80C	1018 (68)
20ХГ2Ц	1032 (3640)
AV (A800)	23Х2Г2Т	(6-8)1032 (3640)
A-VI (A1000)	22Kh2G2AYu, 22Kh2G2R, 20Kh2G2SR	1022

The table is compiled according to GOST 5781-82.

Mechanical properties of reinforcing steel

Bar reinforcement of different brands has individual mechanical properties, which are taken into account when choosing a product for reinforcing concrete structures. The main ones are given in table No. 8 GOST 5781-82:

Reinforcing steel class Yield strength st Tensile strength sv Relative. elongation d5,% Uniform elongation dr, % Impact strength at a temperature of -60 ° Bending and cold testing, where c is the thickness of the sender, d is the diameter of the rod

N/mm2	kgf/mm2	N/mm2	kgf/mm2	MJ/m2	kgf×m/cm2
AI (A240)	235	24	373	38	25	—	—	—	180°; c = d
A-II (A300)	295	30	490	50	19	—	—	—	180°; c = 3d
Ac-II(Ac300)	295	30	441	45	25	—	0,5	5	180°; c = d
A-III(A400)	390	40	590	60	14	—	—	—	90°; c = 3d
A-IV(A600)	590	60	883	90	6	2	—	—	45°; c = 5d
AV (A800)	785	80	1030	105	7	2	—	—	45°; c = 5d
A-VI (A1000)	980	100	1230	125	6	2	—	—	45°; c = 5d

The properties of the reinforcement bars are determined by laboratory tests, based on the results of which a protocol is drawn up. Deviation from GOST rules is allowed in agreement with the customer.

Reinforcement cross-sectional area table

When calculating reinforcing rods, in addition to the diameter, the mass of the products is also taken into account. It is given in the assortment GOST 5781-82:

Nominal diameter of the rod, mmCross-sectional area, cm2Average* weight of 1 m profile

6	0,283	0,222
8	0,503	0,395
10	0,785	0,617
12	1,131	0,888
14	1,54	1,21
16	2,01	1,58
18	2,54	2
20	3,14	2,47
22	3,8	2,98
25	4,91	3,85
28	6,16	4,83
32	8,01	6,31
36	10,18	7,99
40	12,57	9,87
45	15,00	12,48
50	19,63	15,41
55	23,76	18,65
60	28,27	22,19
70	38,48	30,21
80	50,27	39,46

*weight is given as an average value - a more accurate parameter depends on the specific grade used for the production of rolled steel bars.

Areas of application of steel reinforcement

The characteristics of steel reinforcement determine the scope of its application. Smooth profile rods are used:

• For dressing the working rods of the frame;
• Knitting of decorative items for design;
• Installation of individual elements of complex mechanisms.

Periodic profile bars are more in demand:

• Strengthening concrete structures in areas of greatest tension and compression;
• Installation of supporting elements and structures;
• Reinforcement of plaster layers, floor screeds;
• Construction of road surfaces and sidewalk areas;
• Installation of reinforcing belts for laying blocks and bricks.

The main purpose of bar reinforcement with a periodic profile is to strengthen concrete structures. Their rods are knitted into flat or spatial frames. The fittings in them perform different functions:

• Compensation for concrete fracture by creating tensile stress on the rod. Maximum loads are concentrated in the lower part of beam-type structures on two supports or with rigid pinching;
• Compensation for compression that is concentrated in the upper part of the same beam.

Flaws

Bar reinforcement has several disadvantages that need to be taken into account:

• In the absence of an anti-corrosion coating, the rods are subject to oxidation upon contact with water. Processes can even begin from exposure to water in the cement during its hardening.
• Inability to perform functions with rod products if the rod class and its diameter are incorrectly selected.
• Excessively stressed reinforcement can have the opposite effect and form cracks in the concrete structure.
• A protective layer of concrete is required - at least 2 diameters of the section size to prevent water from entering the rods.

Packaging, transportation and storage

For convenience, steel rods are painted in different colors:

• A-IV – red;
• A-V – red and green;
• A-VI – red and blue.

It is allowed to apply paint to the ends of 0.5 meters.

The rod reinforcement is assembled in batches of 15 tons and tied with wire and cordage. Thin wire is also packaged in coils. If necessary, dressings of a different weight are made for the customer - 3 or 5 tons, as well as individual tonnage. Complete bundles must be marked with a class of rods.

Transportation of metal products is allowed only in a horizontal position to avoid kinks and deformations.

It is recommended to store rod reinforcement in closed, dry rooms, excluding contact with water.

Source: https://betonopedia.ru/armatura/stalnaya.html