Purlins are reinforced concrete products, which are horizontal structures of buildings and structures that act as supports for roofs, beams, and ceilings of door and window openings.

Reinforced concrete purlins (RCP) are designed for a load of up to 4 tons per linear meter of element, which allows them to be used in the construction of load-bearing walls. To distribute the load evenly, special supports are used - crossbars or trusses. Moving and installation of products is carried out using special equipment. In order for the grip to be reliable, through holes or loops are made on the upper part of the purlin.

Modern construction cannot be imagined without the installation of reinforced concrete purlins. When constructing multi-storey buildings with a large roof area, these concrete products strengthen the rafter system, act as connecting elements between individual structures, and form the basis for interfloor slabs.

There are different types of reinforced concrete purlins. Depending on their properties, they can be used for the construction of heated or unheated buildings, objects where the roof is laid on lintels, insulated slabs, as well as buildings that are equipped with lightweight enclosing elements.

Technology for producing reinforced concrete purlins

For the production of reinforced concrete purlins, heavy grade concrete (M200, M300) is used. All elements are produced in accordance with GOST 13015-2012 and are carefully checked. Information about the type of product, its dimensions, load class and technical production conditions can be found from the PRG marking.

Reinforced concrete purlins can have:

• Rectangular shape - products with a simple cross-section or with recesses.
• T-shaped - elements with a shelf to support the slab.
• The shape of an inverted letter L - elements with a one-sided shelf.

Depending on the reinforcement and configuration, the following types of T-shaped purlins are distinguished:

• 1PR - the shelf is placed at an angle of 90 degrees to the edge, non-tensioned reinforcement made of longitudinal rods. The structures can be used in the construction of buildings with a roof slope of up to 25%.
• 2PR - the shelf is at an angle of 90 degrees, prestressed reinforcement. The scope of use is the same as that of 1PR.
• 3PR - the shelf is placed at an angle of 90 degrees, pre-stressed reinforcement frame. The structures are used in the construction of objects with a roof slope of up to 5%.
• 4PR - with an oblique flange and non-tensioned reinforcement. The products are used for the construction of buildings with a roof slope of 25%.
• 5PR - with an oblique flange and prestressed reinforcement frame. The structures can be used for the construction of buildings with a roof slope of 25%.

To increase the strength of the purlins, during their manufacture, before concrete begins to be poured, the reinforcing cage in the areas of the planned maximum stress is subjected to compressive stress.

Key advantages of reinforced concrete purlins

Reinforced concrete purlins are widely used in the construction of residential buildings, administrative buildings, and industrial buildings. This is directly related to their many advantages:

• Resistance to heavy loads.
• Resistance to low and high temperatures, elements can be used in the range from -40 to +50 degrees.
• Resistance to aggressive external factors.
• Reinforced concrete products are protected from corrosion.
• Long service life.
• Operational and simple.
• An extensive range of concrete products, which allows you to select the most suitable PRGs.

Advantages of purchasing reinforced concrete purlins from IS GROUP

Any design must be safe. In order for the building to be strong, they mainly use, which vary in their parameters.

Application area

Beams, or reinforced concrete purlins, are made from up to M600, because This material has maximum resistance to crumbling, fire, frost, and water.

Concrete purlins are used as a supporting structure for various small buildings, for example, administration buildings, residential buildings, which are built from bricks or blocks of various types.

Such structures are used in construction in the following areas:

1. In the form of a base that is laid under a layer of slabs between floors. This is especially common in those buildings where load-bearing walls do not have good resistance.
2. How to strengthen the rafter system.
3. Like reinforced concrete lintels that are located over wide doorways and windows. This method of application allows you to relieve stress on this area.
4. As part of the structure in flat roofs where the slope is less than 5%.
5. As an element that connects two parts of one building.
6. To create technological recesses.

There are several types of buildings in which reinforced concrete purlins are most often used. These include:

• unheated buildings, the roof rests directly on concrete purlins;
• heated buildings, the roof is laid on insulated slabs;
• heated buildings with small enclosing structures.

It is necessary to know under what conditions this building material is used. For example, beams can withstand temperature changes outside -40...+50ºС. If there is a seismic source in the region, buildings can withstand fluctuations of no higher than 7 points.

When exposed to a gaseous environment, they tolerate it freely if it is of a non-aggressive type. But any use is permissible if the structure is constructed correctly.

Classification

Since there are many varieties of these designs, it is worth considering each direction in more detail. This will help you understand what the beams are.

By section

The reinforced concrete profile may vary in cross-section. One type has a rectangular cross-section and is a pillar with a recess in it. The second type is the T-bar, which in cross-section resembles the letter T and has a small shelf on which the plates can be installed. The last type of purlins are those that have a shelf on only one side and resemble the letter G in cross-section.

According to the shape of the shelf and type of reinforcement

Products also differ in shape and type of reinforcement.

There are several types, which are designated as follows:

• 1PR means that the shelf can be placed relative to the rib at an angle of 90º, and the reinforcement itself is made of longitudinal rods;
• 2PR means that the shelf is perpendicular to the rib, and the reinforcement has tension (this feature increases the load-bearing properties of the beam);
• 3PR indicates that the shelf is placed perpendicularly, but the frame is tense, because used to support a roof with a slight slope;
• 4PR indicates that the shelf is at a small angle, the reinforcement is tense, and the roof has a large slope;
• 5 PR indicates that the shelf is installed at a slight angle, there is a pre-stressed frame.

Marking

In addition to the above, other types of markings are also used. For example, if the beam has a simple rectangular cross-section, then a combination of the following numbers and letters can be stamped on it - PRG 60.2.5-5AIII.

Deciphered this way:

• PRG is an acronym meaning cross section;
• 60 - dimensions in decimeters, in this case it is indicated that the beam is 6 m long;
• 2 - indicates the width (in dcm);
• 5 — height (in dcm);
• 5 - indicates the permissible load (in tons), in this case 500 kg per 1 linear line. m.
• AIII is the type of reinforcement used.

T-beams also have their own markings. For example, if the product says 2PR-1 AtIV-N, then this means the following:

• 2PR - beam type;
• 1 - serial number, which is responsible for the load-bearing capacity of this reinforcement;
• AtIV - the class to which the fittings belong;
• N - indicates the property of concrete (resistance to various aggressive influences, impermeability).

The letter P at the end of the marking indicates the permeability of the material.

Technical specifications

For the manufacture of such products, high-quality and heavy concrete is used. This allows this building material to have good load-bearing quality.

All design properties are selected individually, and not only the length of the reinforcement is taken into account, but also the features of the reinforcement.

For example, concrete marked M200 is used in cases where the length of the beam does not reach 2.5 m. For reinforcement with a length within 3 m, it is most often used.

If a reinforced concrete beam with a size of 3 to 6 m is needed, then M300 concrete is used for production; for a longer structure, a product marked M350 is suitable.

To make building material, dense concrete is taken, in which the density can be up to 2500 kg/m³. This makes the structure 150 kg heavier. Today, factories produce a large number of such construction beams with various parameters.

Installation features

During construction, it is difficult to install a concrete purlin, because the weight and length of the product’s fittings are large. During installation, it is necessary to use special devices in order to raise the beam to the desired height. For the convenience of lifting beams mechanically, each product has special durable hinges.

Installation is carried out by at least 4 builders, because It is necessary not only to secure the purlin to the lifting equipment, but also to place the beam in the right place. There are several companies in Moscow that produce various types of purlins and have a team that will help carry out the necessary construction work.

Concrete roofing coverings and lintels are the strongest and at the same time one of the most fragile structures that are used in construction. They are able to withstand enormous distributed pressure, but they collapse as soon as a point load is applied to them. As long as the reinforced concrete products have a solid support underneath, they are reliable and durable. If there is empty space underneath them, they begin to bend under their own weight. To avoid concrete destruction, it is necessary to provide it with support from below. And only powerful runs can cope with this task.

Reinforced concrete purlins are reinforced products with increased resistance to bending loads. In essence, this is a powerful long beam for horizontal reinforcement of floors and wide openings, on which other elements of the building structure are laid. The entire applied load is transferred to the auxiliary system of purlins, and they already transfer it to load-bearing walls, trusses or other supports. To obtain the best bending strength characteristics, the purlin profile is made high and narrow. And in order to provide it with reliable and stable support on other components, they are supplemented with shelves.

Classification

The main types are rectangular (PRG) and T-beams (PR) reinforced concrete beams. The latter, depending on the profile features, are divided into two types:

• with a perpendicular shelf - grades from 1PR to 3 PR;
• with diagonal - 4PR and 5PR.

5-centimeter through holes are left in the beams themselves, or metal loops are placed on top for slinging during installation work. The embedded elements (plates, anchors) are coated with an anti-corrosion compound.

Also, purlins may differ in reinforcement scheme:

• unstressed - reinforced only with a steel frame made of AIII rods;
• pre-stressed, where in addition there are longitudinal prestressing rods that increase the load-bearing capacity of the product.

Marking features

Mass production and use began in the 60s. At the same time, a regulatory framework for their production was created - a series of working drawings, according to which concrete factories still produce their products. They were never combined into any single package of documents, so the markings of the purlins are slightly different from different manufacturers.

By brand you can determine not only the dimensions of the product, but also the shape of its section:

• P – general designation for a monolithic purlin.
• P – has supporting flanges, that is, in cross-section it looks like a T-beam.
• G – rectangular profile shape.

After the letter abbreviation, the rounded main dimensions are indicated, expressed in decimeters. Width and height are selected from a series of values ​​- 12-40 and 30-50 cm, respectively, length starts from 2.78 m. General information is followed by the permissible load, that is, the main characteristic of the load-bearing element, expressed in t/m. Next is the symbol for the fittings.

The last thing in the product labeling is the permeability properties of concrete for aggressive gas environments: normal (N) or reduced (P). It may also contain information about embedded elements or the use of heavy concrete (t). The latter is not regulated by GOST, but is separately indicated in a series of working drawings 1.225-2 (issue 12).

Sometimes reinforced concrete purlins of rectangular cross-section PRG are marked differently. After the general abbreviation of the name “P”, the calculated load is placed in hundreds of kilograms per meter of length. That is, P40 is a girder that can withstand, in addition to its own weight, another 4000 kgf/m (series of drawings II-03-02). In later technical documentation, an addition to such markings appeared. The number following the load already indicates the length in decimeters, and after it the letter “p” is placed, indicating the rectangular shape of the profile (1.225-2 issue 5).

Characteristics

To produce purlins, fairly heavy grades of concrete with varying strengths are used. It is selected depending on the size of the product and the characteristics of the reinforcement:

• 3.58 m – M200;
• 2.78 and 3.15 m – M250;
• 5.98 m with spatial reinforcement – ​​M300;
• 5.98 m with prestressed reinforcement - M350.

The density of these concretes reaches 2.5 t/m3, and if we also take into account the dimensions of the reinforced concrete products and the weight of the steel rods, the mass of an individual product turns out to be rather large - from 150 to 1500 kg. The load-bearing capacity of each beam is 39.2 kN/m, which allows them to be used in the construction of large public buildings and residential buildings from blocks or solid bricks. However, it should be taken into account that the specified design load is the limit of the capabilities of a reinforced concrete structure, after which its destruction begins.

When choosing, it is better to focus on the standard indicator (without taking into account the reliability coefficient). For the PRG, these data are given in the accompanying note to a series of working drawings and amount to 28.9 kN/m for long-term exposure or 33.4 kN/m for temporary exposure.

Application and installation

GOST 26992-86, according to which reinforced concrete purlin beams are produced, assumes their use for the installation of flat roof coverings with a slope of no more than 5%. Products with shelves of the 1PR and 2PR brands, as well as 4PR and 5PR, can be mounted on sloping roofs (up to 25%).

However, in construction they are no less widely used to form window openings, strengthen garage and hangar doors, and as rigid supports for slab floors with weak self-supporting ability. These are universal products that can completely replace reinforced concrete lintels or crossbars if the load on the beams is too great.

Due to the considerable weight and work at heights, the use of lifting equipment is required. Related operations are performed by four workers: two riggers below and builders in the area where concrete products are installed. The beam is laid horizontally on cement mortar and supported by walls, load-bearing columns or reinforced concrete cushions, creating an additional stiffening rib. A roofing pie is formed on top or floors made of reinforced concrete slabs are installed.

Price

Purlins are manufactured only in factories according to the series of drawings II-03-02, 1.225-2 and 1.225-1. Special requirements are imposed on their reinforcement and the selection of concrete characteristics in accordance with the purpose and size of the products. So, pouring them directly on site, like a floor slab, will not work - in any case, you will have to look for where to buy beams at the best cost.

The price of reinforced concrete products is influenced by the size of the purlins, that is, their material consumption. The brand of fittings and its consumption play a role. If serial reinforced concrete products are not suitable for the project, non-standard purlins of intermediate sizes can be ordered from the factory. Manufacturers have an impressive range of such products, so finding the necessary beams will not be difficult.

Run	Weight, kg	Price, rub/unit
Rectangular section
PRG 17.1.3-4	150	1 730
PRG 28.1.3-4t	250	2 870
PRG 36.1.4-4	430	3 190
PRG 58.2.5-4	1 450	11 270
P40-28p	240	2 840
P40-36p	410	3 530
P40-60p	1 500	14 220
T-section
PR 45.4.4-3	1 550	3 660
PR 60.4.4-5	2 050	7 820

The release of beams from the factory to end users is strictly regulated by GOST. At the time of shipment, the strength of the concrete surface must be at least 70% of the declared grade. In winter, these requirements become more stringent, so reinforced concrete purlins are supplied with characteristics that are 90-100% consistent with the design ones.

LLC TK "Stroyka" produces and sells reinforced concrete products - reinforced concrete products that are used in the construction industry. Modern production facilities allow us to produce a wide range of products. Thanks to multi-stage control, you receive reinforced concrete products that comply with all current norms and standards.

Elements of buildings and structures

Elements of stairs

Elements of landscaping and road improvement

Engineering Communication

Well elements

Manifold elements

Trays and covers

Rolled metal

Nonmetallic materials

Our company produces and sells the following reinforced concrete products at the best prices:

• FL pillows for the construction of strip foundations;
• driven piles;
• FBS foundation blocks of various brands and sizes;
• rings of wells for water and gas pipelines, communication networks, sewerage;
• floor slabs of all types;
• staircases and flights;
• airfield and road slabs;
• purlins and beams;
• heating main trays.

In addition to the listed concrete products, we produce and sell other reinforced concrete products, and also offer the purchase of non-metallic materials - cement, sand, expanded clay. A complete list of materials is presented in the catalog on the website pages.

Advantages of reinforced concrete products from TK "Stroyka" LLC

Quality according to GOST

Profitable

Reliable manufacturer

The company uses exclusively high-quality raw materials, special additives and components. The production of concrete products is based on the use of functional equipment and the latest technologies. Our products are strong, durable, reliable and meet all established requirements.

The company employs highly qualified specialists. Competent managers will help you select reinforced concrete products for the construction of objects for various purposes. Attention to the requirements and wishes of the customer allows us to effectively solve the most complex problems.

Other advantages of purchasing concrete products from us:

Products comply TU and GOST