Floor slabs (precast concrete, reinforced concrete, reinforced concrete): dimensions, installation, technical characteristics, series

Floor slabs are essential components in modern construction, providing strength and stability to buildings. These slabs come in various forms, including precast concrete, reinforced concrete, and prestressed concrete. Each type offers distinct advantages, making them suitable for different applications and building requirements.

Precast concrete slabs are produced in a regulated factory setting, guaranteeing excellent quality and consistency. After that, these slabs are delivered to the construction site and installed promptly and effectively. This approach is favored by many builders since it shortens construction durations and requires less labor on the job site.

Steel reinforcement is incorporated into reinforced concrete slabs to increase their durability and tensile strength. These slabs can withstand a variety of stresses and heavy loads thanks to the steel and concrete combination. Because of its durability and dependability, reinforced concrete is frequently used in both residential and commercial buildings.

By pre-tensioning the steel before the concrete is poured, prestressed concrete slabs advance reinforcement. By compressing the concrete, this process raises its load-bearing capacity and lowers the chance of cracks. For large-span constructions where extra strength is essential, such as parking garages and bridges, prestretched slabs are perfect.

Floor slab dimensions can change based on the particular needs of the project. Although custom dimensions are also available to fit unique architectural designs, standard sizes are frequently used. Factors like span length, building height, and load-bearing capacity affect the choice of slab size and type.

A building’s structural integrity depends on floor slabs being installed correctly. This entails exact positioning, providing equal load distribution, and fastening the slabs with the proper supports. It is possible to avoid problems like uneven flooring, cracks, and structural weaknesses by using the proper installation techniques.

The technical attributes of floor slabs, such as density, compressive strength, and thermal conductivity, are crucial factors that builders must take into account. These characteristics have an impact on the slabs’ longevity and performance in different environmental settings. Choosing the appropriate slab type for a given project is made easier by being aware of these features.

Floor slabs are frequently divided into series according to their purpose and design. Every series offers solutions for residential, commercial, and industrial buildings, catering to various construction needs. Throughout the planning and construction stages, builders can make more informed decisions by being aware of the applications and specifications of each series.

Main Functions and Applications

A typical reinforced concrete slab is a rectangular, flat piece of concrete with unique hinges on the outside and an internal steel rod frame. These slabs are typically used to install floors in different kinds of buildings and structures. Numerous products exist that vary in terms of weight, size, and specifications.

As a floor, the slab distributes the load-bearing load more equally by taking on the entire weight of the other structural components. The strength, dependability, and longevity of the entire building are directly impacted by the accuracy of the calculations and the choice of suitable slabs.

  • Strength – due to the need to withstand serious calculated load-bearing loads
  • Rigidity – the floor structure must be free of noticeable bends even under heavy loads, in connection with which an acceptable indicator is considered to be 1/200 of the span for attic floors and 1/250 of the span of interfloor floors
  • Thermal protection – especially relevant for residential buildings
  • Sound insulation – to ensure optimal protection of the premises from external sounds
  • Fire resistance – within acceptable limits
  • Economy – a combination of minimum weight with small thickness and high strength/rigidity characteristics is desirable
  • Industriality of all elements, ease of installation
  • The formation of structures of ceilings, structures coatings. Most often, plates are used in such structures in a certain way: the edges of the product are based on runs/walls, the middle part perceives the load (only dispersed, heavy massive objects are prohibited – no columns, etc.D.).
  • Perception of the load and ensuring the spatial stiffness of the building – the slabs are frozen in one whole disk tied strictly to the walls, which is especially true in seismic zones.
  • Arrangement of operated and flat roofs – most often used slabs for buildings and structures. Communications are laid in such plates (but not in the seams).
  • use of used slabs when performing a variety of tasks (except for the main ones – it is better not to make floors from them) – build paths, fences, fences, bridges, access roads, temporary roads, use as a supporting structure for arranging a floor on the ground, etc.d.

Floor slabs can cost up to 20% of the total cost of building construction (dimensions and weights may vary). Consequently, the question of selecting goods with the best qualities at an affordable price is pertinent in this situation.

While cutting corners on quality can hasten the collapse of the structure, it makes no sense to overpay for exceeding limits that are irrelevant to the operation.

Advantages

Precast floor slabs made of reinforced concrete have benefits and drawbacks. Different product types are actively used in the construction of specific objects because there are numerous additional benefits to using them in the installation of different buildings.

  • Correct geometric dimensions, evenness and smoothness of the slabs – which greatly facilitates calculations, installation, and further finishing of surfaces.
  • Simplicity of construction – no need for mounting supports or formwork, slabs are easily and simply mounted in any structure.
  • Speed ​​of work execution – immediately after installation, the slab can be used (and not wait, as in the case of pouring concrete, 28 days).
  • Possibility to load the slab immediately after installation is complete.
  • Excellent soundproofing and heat-insulating characteristics.
  • High strength, reliability, rigidity.
  • Easier installation of various communications – when a precast reinforced concrete floor is made from hollow-core slabs, in the holes of which cables, pipes, etc. can be laid..

Slabs have certain drawbacks when it comes to construction, not the least of which is the requirement for specialized equipment during installation and the potential for delivery issues. However, these drawbacks are only temporary, as many businesses in Moscow and the surrounding areas produce slabs, and renting a crane is not a difficult task.

Types of slabs

GOST 9561-91 specifies all of the slabs’ technical features. A vast array of products exist that differ in terms of weight, length, height, and thickness. However, they are all separated into a number of groups, each with a unique set of requirements and application range.

Hollow and hollow-core

The majority of the time, these slabs of reinforced concrete are found and utilized in various kinds of buildings. Both single-story and multi-story building construction can benefit from the use of hollow-core slabs. In addition to being used in the construction of large industrial facilities, hollow-core slabs are also frequently used to safeguard heating mains.

The existence of through holes, or voids, in the monolith is the primary distinction between hollow-core slabs and other products. The products have a smooth, flat surface, and holes run the length of the rectangle—which can have any shape—for reinforcement. An oval, round, or semicircular holes are placed inside the product for added strength.

During the installation process, the technological voids are filled with air, which simultaneously provides several effects at once.

  • Significant savings in material for the production of slabs, which accordingly affects the cost of the product.
  • High noise and heat insulation, which significantly improves the performance characteristics of the building.
  • The ability to lay various pipes, wires, and other parts of communication lines in the holes.
  • A significant reduction in the weight of the slab itself, which reduces the weight of the building, is necessarily taken into account in the calculations.

The slabs may vary depending on the installation technique: Whereas 1 PKK has four supporting sides, 1 PKT has three. Additionally, consider the size of the internal voids when making your selection. A panel with a smaller diameter will be stronger and more resilient, but it will also weigh more. Therefore, for 1 PKK and 2 PKT slabs, the width, height, length, and number of supporting sides are the same; however, the holes’ diameters are different: in the first case, they are 159 millimeters, and in the second, 140 millimeters.

The standard thickness of a hollow-core reinforced concrete floor slab is 22 centimeters, and this determines the slab’s strength in large part. Additionally, there are panels that are 30 centimeters thick; lightweight panels, which are made of lightweight concrete, can be 16 centimeters high.

Hollow-core slabs can support a load of roughly 800 kg/m^2. For modestly sized, single-story buildings, this is more than sufficient. Massive structures are put together using slabs that have 1250 kg/m2 of prestressed reinforcement.

A reinforced concrete floor slab typically measures 1.5–1.6 meters in length, 1.2, 1.5, or 1.8 meters in width, and weighs between half a ton, which is the lightest, and up to 4 tons, which is the largest product. Round-void slabs are incredibly simple to work with and come in a variety of sizes, so selecting the ideal one for any building won’t be tough.

Ribbed U-shaped

A unique component used in the construction of ribbed reinforced concrete floor slabs are two longitudinal stiffeners. These products are typically utilized during the construction of non-residential buildings as load-bearing components for the later installation of heating plants and water supply networks.

Steel reinforcement, either in a stressed or non-stressed state, is used to reinforce reinforced concrete floor slabs. The slabs become incredibly strong and flex-resistant. In residential buildings, they are typically not installed between floors because doing so causes issues with ceiling finishing (the ceiling ends up ribbed, which is not very aesthetically pleasing).

There are two height options for ribbed slabs: 30 and 40 centimeters.

Items Lintels between the building’s top floor and attic are 30 centimeters thick. The most common height for slabs used in the installation of large industrial and commercial buildings is forty centimeters.

Ribbed slabs come in widths of 1.5 or 3 meters and lengths of 6, 12, or 18 meters (very rare). The product’s weight can range from 1.5 to 3 tons; in the most rare circumstances, it can even weigh up to 7 tons.

Tent ribbed monolithic

Ribbed panels made of reinforced concrete are produced in compliance with GOST 21506 or 27215. Flat components known as hopper floor slabs are made to support a building’s operational loads and transfer them to the structures below.

This kind of slab can support loads of between 400 and 500 kg/m^2. Slab floors are particularly resistant to vibration loads because they have longitudinal stiffeners, which is why they are frequently used in areas with higher seismic activity.

  • Height – 22, 30, 40 centimeters
  • Width – 120, 150 centimeters
  • Length – 6 or 12 meters

The primary benefit of this kind of product is that it weighs significantly less than comparable panels. Because the floor at the slab’s base is only 5 centimeters thick, a slab that is 6 by 1.5 by 0.3 meters will only weigh 1.5 tons.

  • PP – for covering buildings as a roof for structures without an attic. The slabs are made prestressed, there are no openings in the shelf.
  • PR – for installing floors at sites, produced with non-stressed reinforcement.
  • PG – suitable for covering objects, these are additional slabs with non-stressed reinforcement.
  • PV – panels with a special opening in the shelf for a roof fan or ventilation shaft.
  • 1P – products for supporting beams on shelves.
  • 2P – panels for supporting beams from above.

Technical characteristics

Both solid and hollow-core floor slabs are available in a range of sizes and design options, which inevitably influences the properties and is represented in the marking.

Classification and marking

Slab marking is done in compliance with GOST. All of the specifications are displayed on the slab’s side using numbers and letters, including the dimensions, weight, bearing capacity, date of production, and so on.

  • The first letters indicate the type: PB – solid concrete slabs; PK – hollow; NV, NVK, 4NVK – ribbed reinforced concrete.
  • The third letter indicates the presence of an additional support side for the product: T indicates three sides, K – four.
  • The first 2 digits at the beginning are the length of the slab, displayed in decimeters.
  • The second two digits are the width (usually 1-2 centimeters more than the real one).
  • The last digit is the design load.
  • The next group of alphanumeric designations indicates various additional parameters (the presence of mounting loops, product class, etc.).d.).
  • The first digit of the marking indicates the thickness of the product: 1 means 10 centimeters, 2 is 12 centimeters, 3 is 14 centimeters, 4 is 16, 5 means a slab with a thickness of 18 centimeters, 6 is 20 centimeters.
  • 1P-6P – the slab rests on 4 sides.
  • 3PT-6PT – on 3 sides.
  • 2PD-6PD – rest on 2 sides.

Consequently, the slab’s PK 51.15-8 marking denotes that it is a hollow-core floor; the product’s length is 54 decimeters (5.4 meters), and its width is 15 decimeters (1.5 meters).

Furthermore, as per GOST 12767-94, the dimensions and characteristics of the slab can be encrypted within its name. The presence of structural elements in the slabs for installation and connection of products with metal / reinforced concrete elements is typically determined in regulatory documents rather than in marking. Aside from mounting loops, the slabs have channels for communications cabling.

Mass

The weight of the floor slabs varies and is directly related to their dimensions and the existence or absence of internal voids. The range of the indicator is 960–4820 kg. The structure’s installation method is determined by its weight. The majority of the time, five-ton cranes are used to install the slabs.

It is important to keep in mind that slab weights, even those with identical markings, can vary slightly at first and when specific factors are taken into account. For instance, the panel will weigh more if it is left outside in the rain.

Dimensions

There are various sizes available for floor slabs made of reinforced concrete nowadays.

  • Length – from 1.6 to 15 meters
  • Width – 0.6, 1.5 meters, as well as 1.8, 2.4
  • Thickness – 22 centimeters

Almost any building can be easily designed with the options currently available. It is possible to create slabs in accordance with specific orders if needed.

The typical dimensions of reinforced concrete products made from heavy and lightweight concrete with voids are 2.4–6.6 meters in length, 0.6–2.4 meters in width, and 22 centimeters in thickness. The standard weight of these products ranges from 900 to 2500 kilograms.

The following standard sizes are most frequently produced in solid slabs: 6.6 lengths (with a thickness of 16 centimeters) and 2.6–4.2 meters in length (if the thickness is 12 centimeters). Standard panels range in width from 1.2 to 2.4 meters. Goods with a maximum thickness of 16 centimeters are deemed heavy and provide superior sound absorption. You must take extra care to insulate against sound if you select 12 centimeter-thick reinforced concrete products.

Use 2T floor slabs with the following dimensions to create floors with standard spans of 9, 12, and 15 meters: 3 meters in width and 6 meters in height along the edge.

Bearing load

The primary parameter is the established bearing capacity of each floor. The size and arrangement of the slabs have an impact on the bearing load. Therefore, in the case of hollow-core panels, the length, width, and various shapes of the voids have an impact on the calculations. The lower portion of the hollow-core slabs is reinforced, which has an immediate impact on strength. Reinforcement is applied to the upper portion of the slab less frequently.

During the design phase, the load on the floor slabs and bottoms is computed. The indicator ranges from 800 to 1450 kgf / sq.m.m., depending on the type of concrete and the geometric parameters of the slab.

The types and corresponding types of floor slabs are composed of M300 or M400 grade cement. As a result, 400 kg/m3 of load can be supported by cement grade M400 per second. This does not imply that things will always work this way; the panel will be able to support the maximum load for a while, but not always. Although cement M300 has a higher plasticity and resistance to deflection, it can support lower loads.

Reinforcement results in an increase in bearing capacity. Steel rods of class A3 or A4, which have anti-corrosion qualities and resistance to temperature changes in the range of -40 to +50 degrees, are used to reinforce the hollow slab.

In order to transfer the stress from the elements in tension to the entire panel body, a mesh is installed after the reinforcement is stretched in the form during the production process. The tension reinforcement is cut once the concrete has been poured and allowed to harden.

Reinforced concrete floor slabs can support heavy loads without buckling or deflecting because of the reinforcement. To ensure that the ends support the weight of the upper load-bearing walls and do not collapse under their own weight, double reinforcement is applied to them.

Manufacturing technology

Floor slabs come in a variety of varieties, each produced uniquely. Slabs for PG, PK, and PB are made continuously on a conveyor line, while slabs for PB are cast in formwork. As a result, PB slabs can be any length and are smoother and more even.

The process of creating slabs made with formwork is very straightforward: prestressed or non-prestressed reinforcement is positioned in specific forms, concrete of a certain grade is poured, the slabs are left to dry and harden, the reinforcement (if any) is cut, and the panels are delivered for purchase. PB slabs are continuously poured onto a conveyor and then cut into the necessary lengths of panels.

Conversely, PG and PC slabs allow communications to be freely laid in openings measuring at least 114 millimeters without worrying about the structure as a whole collapsing. The PB has a smaller aperture (roughly 60 millimeters), so in this case, cutting the ribs and weakening the entire structure is required to lay the communications risers. All of this must be taken into consideration when calculating the reinforced concrete floor slab.

Approximate prices

Floor slabs can range widely in price. Everything is dependent on the manufacturing process, the type of concrete used, the quantity of reinforcement, and the distance from the factory to the delivery location. Custom-sized panels are significantly more expensive.

  • PK 30.12-8 – from 5,000 rubles
  • PK 30.15-8 – from 5,500 rubles
  • PK 40.15-8 – from 7,500 rubles
  • PK 48.12-8 – from 7,000 rubles
  • PK 51.15-8 – from 9,500 rubles
  • PK 54.15-8 – from 10,000 rubles
  • PK 60.12-8 – from 8000 rubles
  • PK 60.15-8 – from 10500 rubles
Type Details
Precast Concrete Dimensions: Varies, common sizes 1200mm x 600mm; Installation: Lifted and placed with cranes; Characteristics: Durable, customizable shapes
Reinforced Concrete Dimensions: Typically 1500mm x 600mm; Installation: Requires cranes and skilled labor; Characteristics: Strong, good for heavy loads
Reinforced Concrete Dimensions: Standard 1600mm x 800mm; Installation: Heavy machinery needed; Characteristics: High tensile strength, versatile
Series Different series available depending on manufacturer, consult local supplier

Floor slabs are essential to construction because they give all kinds of buildings the support and stability they need. Each type of concrete slab—prestressed, reinforced, and precast—offers special advantages suited to various architectural requirements. Because precast concrete slabs are produced in controlled environments, they are renowned for their uniform quality and ease of installation. Steel reinforcements give reinforced concrete slabs increased strength and durability, which makes them perfect for heavy loads and high-traffic areas. By adding tensioned steel strands, prestressed reinforced concrete slabs advance the concept by enabling longer spans without sacrificing strength.

It is crucial to comprehend the dimensions and technical features of floor slabs when making decisions about them. Although standard sizes differ, they can span lengths of up to 12 meters and have thicknesses ranging from 100 to 300 mm. These measurements affect the slabs’ ability to support loads and their flexibility, which has an effect on the structure’s overall layout and functionality. Selecting the appropriate slab type and size is crucial to guaranteeing that it fulfills the particular demands of your project.

It takes precision and careful planning to install floor slabs. Because they are easy to install and require less time and labor on the construction site, precast slabs are frequently chosen. Although more complicated, prestressed and reinforced slabs provide unmatched durability and performance, making the extra work required to install them worthwhile. In order to preserve the integrity of the slabs and guarantee a stable, level floor, proper handling and placement are essential.

Different floor slab series are made to fulfill different building codes and requirements. These series are divided into groups according to the type of application, span length, and load capacity. Knowing these series will assist you in choosing the best slab for your project, guaranteeing adherence to building codes and obtaining maximum performance.

In conclusion, selecting the appropriate floor slab is an essential choice for any building project. You can improve the strength, longevity, and efficiency of your building by selecting a precast, reinforced, and prestressed reinforced concrete slab based on your understanding of the differences between these types of slabs as well as their dimensions, installation methods, and technical specifications. Floor slabs have a big impact on the longevity and overall success of your construction projects if you choose them wisely.

Precast, reinforced, or prestressed concrete floor slabs are all necessary elements of contemporary construction. These slabs are available in a range of sizes and provide a variety of technical features to accommodate a range of building requirements. Selecting the appropriate type for a project can ensure structural integrity and efficiency if one is aware of its specifications, installation techniques, and series affiliation.

Video on the topic

Reinforced concrete slabs PB and PK – What is the difference?

We dismantle buildings into reinforced concrete floor slabs, used reinforced concrete, hollow reinforced concrete floor slabs

#installation #slabs #floors #reinforced concrete #crane #aerated concrete #monolith

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Dmitry Sokolov

Chief engineer in a large construction company. I have extensive experience in managing construction projects and implementing modern technologies.

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