A purlin is a part of the structure of prefabricated reinforced concrete or brick structures, installed in a horizontal position and supported by load-bearing beams or trusses. The elements themselves also have impressive strength and are used as support for floor slabs or decking. There is a separate GOST for reinforced concrete purlins, which regulates all the requirements that products must meet.
In the photo - the purlins rest on the beams and perform a load-bearing function during the installation of floors and roofing decks
Main features of this type of structure
All purlins manufactured at factories of reinforced concrete products must comply with the standards of GOST 26992-86 “Reinforced concrete purlins for covering buildings of industrial and agricultural enterprises.” It is this regulatory document that determines what requirements each product must meet, and a number of indicators are regulated:
| Strength | The design load of the products must be at least 4,000 kgf/m, which allows the elements to be used in the construction of load-bearing walls. |
| Types of sections | There are two types of sections: rectangular and T-shaped. In construction reference books you can also find Z-shaped and C-shaped purlins, but they are a metal profile and are not used as elements of load-bearing structures. |
| Production material | The manufacturing material is heavy concrete grade M250, and for structures 6 meters long or more it is necessary to use the even more durable grade M350. |
| Reinforcement | There are two main options for reinforcement: unstressed, consisting of a spatial steel reinforcement frame, and stressed, which consists of prestressed reinforcing bars and a spatial frame. |
| Installation features | It is important to remember that the weight of the products is very large and it is unlikely that you will be able to carry out installation work yourself - you will need lifting equipment. It is for this reason that purlins are not often used in private development. |
Important! Do not confuse purlins with jumpers. Lintels are used for similar purposes, but are much smaller in size and are not designed for heavy loads and cannot be used in load-bearing systems. Purlins are suitable for any purpose: from strengthening openings (especially large ones) to creating additional strength in places where reinforced concrete slabs support.
Purlins are much larger and more massive than jumpers
Types of purlins
Products are divided according to the type of section. There are two main options, each of which we will consider in more detail.
Rectangular elements
From the name it is clear that this type of product has a rectangular shape and is marked with the designation PR. The scope of their use is quite wide; such elements can be found in many structures.
Each of the parameters is indicated by a Latin symbol, so that all the main parameters can be easily determined by the markings
Let us note the main features of this group of products:
Some options are very tall
Do not forget that the dimensions of reinforced concrete purlins are written in decimeters, the letter “T” means that heavy concrete was used for production. If there are additional factors, they are also noted in the labeling. Labeling instructions are the same for all manufacturers, so it is important to know the general rules.
Example. Let's look at the version of the 44.3.5-4T run, the marking indicates that the length of the element is 44 decimeters, the thickness is 3, and the height is 5 Dm, the design load is 4 tons per meter, heavy concrete was used in the manufacture.
Elements with T-section
Such elements are especially often used in areas with increased seismic activity, as they can withstand shocks of up to 7 points
For this group of products we can say the following:
With the help of T-purlins you can create a very durable structure
Remember! Whatever option you choose, it is important that it is manufactured in accordance with GOST standards. Since it will be subjected to significant loads, the quality must be at the highest level.
The purlin is a mandatory element for strengthening any industrial structure, which is why it is so important to choose the option that is optimal in size and characteristics. The video in this article will highlight the nuances and features in more detail.
Reinforced concrete purlins PRG are manufactured in accordance with series 1.225-2, designed for covering openings in the walls of public buildings and administrative buildings made of brick or wall blocks and designed for a design pressure of 4000 kgf/m, i.e. used in load-bearing walls with the ability to support both PC floor slabs and overlying masonry.
They are made of heavy concrete grade M-250 for compression, and for 6-meter ones - M-350. Reinforcement is possible in 2 options: prestressed, reinforced with prestressed reinforcing bars of the AtV brand and spatial frames and unstressed, reinforced only with spatial steel frames. Most often they are produced unstressed, i.e. with conventional reinforcement
Since the load of the overlying wall is quite large, and the surface area on which the purlin presses is quite small, it is recommended to use support slabs as linings during construction, which allow the load to be distributed over a larger surface.
The standard length of the product provided by the series can be 2.8; 3.2; 3.6; 4.2; 4.8; 5.4 and 6 meters. However, it is possible to produce reinforced concrete purlins and intermediate sizes upon request.
The marking consists of alphanumeric groups separated by a hyphen:
For example, PRG 32.1.4-4AtV - a rectangular girder with a length of 3180 mm, a width of 120 mm, a height of 400 mm under a design load without taking into account its own weight of 39.2 kN/m (4 tn/m), reinforced with AtV steel, i.e. . pre-stressed.
| Dimensions | Max opening width | Min support | Load kgf/m | |||
|---|---|---|---|---|---|---|
| Length | Width | Height | ||||
| PRG28.1,3-4 | 2780 | 120 | 300 | 2420 | 180 | 4000 |
| PRG32.1,4-4 | 3180 | 120 | 400 | 2820 | 180 | 4000 |
| PRG36.1,4-4 | 3580 | 120 | 400 | 3220 | 180 | 4000 |
| PRG42.2,5-4 | 4180 | 200 | 500 | 3780 | 200 | 4000 |
| PRG48.2,5-4 | 4780 | 200 | 500 | 4380 | 200 | 4000 |
| PRG54.2,5-4 | 5380 | 200 | 500 | 4980 | 200 | 4000 |
| PRG60.2,5-4 | 5980 | 200 | 500 | 5580 | 200 | 4000 |
A purlin is a part of the structure of prefabricated reinforced concrete or brick structures, installed in a horizontal position and supported by load-bearing beams or trusses. The elements themselves also have impressive strength and are used as support for floor slabs or decking. There is a separate GOST for reinforced concrete purlins, which regulates all the requirements that products must meet.
In the photo - the purlins rest on the beams and perform a load-bearing function during the installation of floors and roofing decks
All purlins manufactured at factories of reinforced concrete products must comply with the standards of GOST 26992-86 “Reinforced concrete purlins for covering buildings of industrial and agricultural enterprises.” It is this regulatory document that determines what requirements each product must meet, and a number of indicators are regulated:
| Strength | The design load of the products must be at least 4,000 kgf/m, which allows the elements to be used in the construction of load-bearing walls. |
| Types of sections | There are two types of sections: rectangular and T-shaped. In construction reference books you can also find Z-shaped and C-shaped purlins, but they are a metal profile and are not used as elements of load-bearing structures. |
| Production material | The material used is heavy, and for structures 6 meters or more in length it is necessary to use the even more durable M350 grade. |
| Reinforcement | There are two main options for reinforcement: unstressed, consisting of a spatial steel reinforcement frame, and stressed, which consists of prestressed reinforcing bars and a spatial frame. |
| Installation features | It is important to remember that the weight of the products is very large and it is unlikely that you will be able to carry out installation work yourself - you will need lifting equipment. It is for this reason that purlins are not often used in private development. |
Important! Do not confuse purlins with jumpers. Lintels are used for similar purposes, but are much smaller in size and are not designed for heavy loads and cannot be used in load-bearing systems. Purlins are suitable for any purpose: from strengthening openings (especially large ones) to creating additional strength in places where reinforced concrete slabs support.
Products are divided according to the type of section. There are two main options, each of which we will consider in more detail.
From the name it is clear that this type of product has a rectangular shape and is marked with the designation PR. The scope of their use is quite wide; such elements can be found in many structures.
Let us note the main features of this group of products:
Do not forget that the dimensions of reinforced concrete purlins are written in decimeters, the letter “T” means that heavy concrete was used for production. If there are additional factors, they are also noted in the labeling. Labeling instructions are the same for all manufacturers, so it is important to know the general rules.
Example. Let's look at the version of the 44.3.5-4T run, the marking indicates that the length of the element is 44 decimeters, the thickness is 3, and the height is 5 Dm, the design load is 4 tons per meter, heavy concrete was used in the manufacture.
For this group of products we can say the following:
Remember! Whatever option you choose, it is important that it is manufactured in accordance with GOST standards. Since it will be subjected to significant loads, the quality must be at the highest level.
The purlin is a mandatory element for strengthening any industrial structure, which is why it is so important to choose the option that is optimal in size and characteristics. The video in this article will highlight the nuances and features in more detail.
Reinforced concrete products help ensure the strength of building structures. Their shapes and sizes are varied. Some are produced directly on the construction site, others are prepared in production. No construction is complete without reinforced concrete purlins.
The appearance and structure of the purlin are almost no different from a reinforced concrete pillar. Outwardly, they look like hardened concrete mortar with a metal frame inside. What is the difference between the runs? The designs are distinguished by their large mass, long length and enhanced strength. The production of structures is not on stream; their production is associated with the need for the element to withstand a certain load.
Reinforced concrete purlins are used in construction to solve an important problem. For example, not a single opening can be made without using a purlin. Only after its installation are the floor slabs attached. And reinforced products made under the influence of heat treatment can withstand heavy loads. They are used in the construction of public and industrial buildings with brick and reinforced concrete walls. Most often they are used in the construction of openings, supports on which floor slabs are attached.
Installation of the purlin: a) view of the support on the wall; b) on a pole; 1. reinforced concrete pad; 2. runs. Reinforced concrete purlins are prepared exclusively in an industrial manner, in accordance with state construction standards. For their production, only heavy concrete is used, most often M200 and M300, with the use of reinforcement for reinforcement. The use of structures in favorable conditions increases the service life of buildings.
Reinforced concrete purlins are divided into types, which are formed according to the shape of the product and the grade of concrete. The purlins are assigned the following types
Channels and I-beams are used in production. This type is divided into two types:
These designs can be used for unheated rooms. They are used in temperatures ranging from -40 to 50 degrees and exposure to gas. A characteristic feature is the ability to use products in the construction of structures in hazardous, seismically active zones.
The difference is the presence of special holes, through which the gripping devices are inserted, making it easier to lift and install the elements. T-section elements are suitable for the construction of buildings:
This type of purlin has an I-beam division. The rectangular cross-section of the purlins can be solid or lattice. The lattice type is lighter, the spacing of products is 6 meters, so it is used in construction much more often. To produce a continuous type, bent channels are used. Products with a rectangular cross-section have thin walls, but excellent height. The strength of the products is ensured by specially created fastening bends.
Example of marking runs. The manufacture of building structures is approached in compliance with state standards and technologies. You can get maximum information about products by studying the product series. An inexperienced builder will not be able to obtain complete information on markings without knowledge. It is worth focusing on the transcript data.
For ease of use, a special classification in letters and numbers is used. They encrypt information about length, height, width, and support load. The first letters encrypt information about the series of runs:
The second group of signs contains information about the load and type of reinforcement. The third signs indicate the specific purpose of the material, including the features of the use of concrete composition.
For example: PRG 28-1-3-4t. PRG - rectangular section. The following series of numbers indicates the dimensions of the structure: 2800 mm long, 100 mm wide, 300 mm high. The 4t indicator indicates the ability to withstand a load of 4 tons per meter.
