Reinforcement for concrete structures

Reinforcement for reinforced concrete structures (RCS) is an essential component that ensures their strength and operational resistance to tensile and compressive forces. Reinforcement in reinforced concrete structures is installed to compensate for tensile stresses and enhance the concrete in compression zones. The amount of reinforcement is determined based on the load and impact on the structural elements.

This rolled metal product is either hot-rolled or cold-rolled, with a round or periodic profile. It is supplied in bars, coils, or bundles. The nominal diameter ranges from 4 to 50 mm.

If reinforcement is installed based on calculations, it is referred to as working reinforcement; if installed for technological or structural reasons, it is called mounting reinforcement.

Mounting reinforcement evenly distributes forces among individual working reinforcement bars and can also absorb unaccounted loads after concrete shrinkage, temperature changes, or environmental impacts.

Both types of reinforcement are collectively referred to as reinforcement products.

Types of Reinforcement

All reinforcement is classified based on four criteria:

1. Reinforcement is divided into hot-rolled bar or cold-drawn wire. Depending on the manufacturing technology, bar reinforcement can be supplied in bars, coils, or bundles weighing up to 1300 kg.
2. Depending on the method of further strengthening, hot-rolled reinforcement can be thermally strengthened or strengthened in a cold state, for example, by drawing or pulling.
3. By surface characteristics. It can be smooth or have a periodic profile. Ribs, ridges, or indentations on the surface of wire reinforcement significantly improve adhesion to concrete.
4. By application method, reinforcement is distinguished as pre-stressed (tensioned during installation) or non-pre-stressed.

Reinforcement in the form of I-beams, channels, or angles, before the concrete hardens, functions as a structure bearing loads from its own weight and any suspended weight. Such a structure is suitable for monolithic and long-span floors, as well as columns on lower floors that experience significant loads.

Production Standards

Currently, the following standards are in force in Ukraine:

DSTU 3760:2019 «Steel reinforcement for reinforced concrete structures, general technical requirements». Its scope covers reinforcing bars with smooth or deformed (ribbed) profiles, describing both non-prestressed reinforcement and steel for prestressed reinforced concrete structures. According to this standard, reinforcing steel is produced in the following classes: B240 (with smooth profile), B500A, B500B, B500C, B500E, B600, B800, B1000 (all with ribbed profiles). It applies to profiles with diameters ranging from 5.5 to 40 mm.

DSTU 9130:2021 «Hot-rolled reinforcing steel for reinforced concrete structures. Technical specifications». This describes requirements for reinforcing steel classes B240 (with smooth profile), B500A, B500B, B500C, B500E, B600, B800, B1000 (all with ribbed profiles) with diameters from 6 to 80 mm in bars and coils.

It is worth noting that thermal treatment is applied to four classes, the presence of this technological process is indicated by an additional "T" index. Also, the marking may include the following letters:

• «C» - indicating weldability;
• «K» - indicating enhanced corrosion resistance.

Periodic profiles are present in bars of all classes except the first.

The physical yield strength for classes 1–3 ranges from 230 to 400 MPa. Other classes have this parameter within 600–1000 MPa.

Reinforcement wire with a diameter of 3–8 mm is divided into two classes: BP-1, standard cold-drawn reinforcement wire, intended for the production of welded meshes.

BP-2 is high-strength reinforcement wire used as elastic reinforcement for pre-stressed elements.

A periodic profile is designated by the index “R”.

The main characteristic of wire reinforcement is its temporary resistance, which increases as the wire diameter decreases. For high-strength wire, it ranges from 1300 to 1900 MPa.

The modulus of elasticity for second-class reinforcement wire is 2·10⁵ MPa, for BP-2 – 1.7·10⁵ MPa, and for reinforcement ropes – 1.8·10⁵ MPa.

The assortment of this metal product is based on nominal diameters, which, for reinforcement with a periodic profile, correspond to the diameter of smooth round bars with an equivalent cross-sectional area. For standard and high-strength reinforcement wire, it refers to the wire before profiling.

Features of B500B and B500C

Among the most popular classes are reinforcement B500B and B500C.

According to recommendations for the use of reinforcement steel, these are recommended for use as longitudinal and transverse reinforcement. However, class B500C has significant advantages in the following characteristics:

• normative resistance;
• reliability coefficient of reinforcement;
• design resistance.

It should be noted that its use allows for a reduction in the metal intensity of reinforced concrete structures without any negative impact on their characteristics. Additionally, it is used in cases where B400BWR cannot be applied due to insufficient strength.

You can order reinforcement online on the UTMK website or by phone. You can pick up the goods from warehouses in Kyiv, Zaporizhzhia, Dnipro, and Odesa. Discounts are available for bulk buyers. Contact us, and we will also assist in arranging delivery to any location in Ukraine, including Lutsk, Mykolaiv, Lviv, and Ternopil. Polish customers can make purchases in the Polish cities of Warsaw, Krakow, Łódź, and Poznań. Bending and cutting of steel are also available. We deliver to Polish cities such as Płock, Kalisz, and Opole. Contact us, and our managers will be happy to answer all your questions.