| Floor slabs multi-hollow GOST 9561-91 | ||||
| Name | Dimensions (LxWxH, mm) | Volume, m3 | Weight, t | Price for 1 unit. with VAT, rub. |
| PC 24-12-8 AtV T | 2380x1190x220 | 0,36 | 0,9 | 4306 |
| PC 27-12-8 AtV T | 2680x1190x220 | 0,40 | 1,01 | 4799 |
| PC 30-12-8 AtV T | 2980x1190x220 | 0,44 | 1,11 | 5429 |
| PC 33-12-8 AtV T | 3280x1190x220 | 0,49 | 1,22 | 5934 |
| PC 36-12-8 AtV T | 3580x1190x220 | 0,53 | 1,32 | 6439 |
| PC 39-12-8 AtV T | 3880x1190x220 | 0,57 | 1,42 | 6944 |
| PC 42-12-8 AtV T | 4180x1190x220 | 0,61 | 1,53 | 7383 |
| PC 45-12-8 AtV T | 4480x1190x220 | 0,65 | 1,62 | 7532 |
| PC 48-12-8 AtV T | 4780x1190x220 | 0,69 | 1,73 | 8004 |
| PC 51-12-8 AtV T | 5080x1190x220 | 0,73 | 1,83 | 8474 |
| PC 54-12-8 AtV T | 5380x1190x220 | 0,78 | 1,95 | 8910 |
| PK 57-12-8 AtV T | 5680x1190x220 | 0,82 | 2,05 | 9347 |
| PC 60-12-8 AtV T | 5980x1190x220 | 0,86 | 2,15 | 9886 |
| PC 63-12-8 AtV T | 6280x1190x220 | 0,90 | 2,25 | 10421 |
| PC 72-12-8 AtV T | 7180x1190x220 | 1,01 | 2,53 | 13405 |
| PC 24-15-8 AtV T | 2380x1490x220 | 0,50 | 1,25 | 4774 |
| PC 27-15-8 AtV T | 2680x1490x220 | 0,55 | 1,38 | 5397 |
| PC 30-15-8 AtV T | 2980x1490x220 | 0,60 | 1,52 | 5916 |
| PC 33-15-8 AtV T | 3280x1490x220 | 0,65 | 1,61 | 6642 |
| PC 36-15-8 AtV T | 3580x1490x220 | 0,70 | 1,75 | 7265 |
| PC 39-15-8 AtV T | 3880x1490x220 | 0,74 | 1,85 | 7784 |
| PC 42-15-8 AtV T | 4180x1490x220 | 0,80 | 2,02 | 8407 |
| PC 45-15-8 AtV T | 4480x1490x220 | 0,88 | 2,2 | 8834 |
| PC 48-15-8 AtV T | 4780x1490x220 | 0,94 | 2,35 | 9437 |
| PC 51-15-8 AtV T | 5080x1490x220 | 0,99 | 2,48 | 9861 |
| PC 54-15-8 AtV T | 5380x1490x220 | 1,05 | 2,63 | 10427 |
| PC 57-15-8 AtV T | 5680x1490x220 | 1,10 | 2,75 | 11010 |
| PC 60-15-8 AtV T | 5980x1490x220 | 1,14 | 2,85 | 11744 |
| PC 63-15-8 AtV T | 6280x1490x220 | 1,19 | 2,98 | 12343 |
| PC 72-15-8 AtV T | 7180x1490x220 | 1,34 | 3,35 | 16734 |
Hollow-core reinforced concrete floor slabs are used in the construction of load-bearing structures of buildings and structures. The voids inside the slabs are designed to improve sound insulation and reduce the weight of the structure. Top side the floor slabs will be the base of the floor, and the underside will be the ceiling. Hollow-core floor slabs are used in individual construction of houses, in the construction of residential and industrial multi-storey buildings.
Based on their external shape, floor slabs are divided into flat and ribbed. Flat slabs, in turn, are multi-hollow and solid. Our company produces hollow core slabs PC floors. The diameter of the round voids is 159mm, the thickness of the slabs is also standard and is 220mm. These slabs are intended for laying on top of load-bearing walls with support on two end sides.
Hollow-core slabs can withstand enormous loads, but they cost special attention regarding the storage of these products. To store the slabs, it is necessary to prepare a flat surface in advance, pour and compact a sand cushion. The slabs should never be laid directly on the ground. Along the edges at the bottom of each slab it is necessary to place wooden blocks. There should be two bars, at a distance of about 25-45 cm from each edge. It is strictly not recommended to place bars under the middle part of the slab in order to avoid cracks and breaks. Stacking of hollow-core floor slabs is permitted in a stack no more than 2.5 meters high.
The floor slabs lie flat and without differences. To do this, it is necessary to ensure that all the upper rows of load-bearing walls are positioned in the same horizontal plane. Before laying hollow-core slabs on walls made of blocks (foam concrete, aerated concrete, cinder block), it is necessary to make a reinforced concrete belt in advance. Its thickness should be between 15-25cm. When installing hollow-core slabs, the holes in them are sealed. This can be done in advance when the slabs are stacked on the ground. Hollow-core slabs are laid using a thick mortar. The layer of solution should not exceed 2 cm.
The solution is applied over brickwork. This is done in order to cover the gaps if there are differences, as well as for a better fit of the slabs. The solution sets in 15-20 minutes; during this period of time, you can move the slab to align its position relative to the walls. To avoid hardening of the solution, it is applied immediately before lifting the floor slab. The hollow core slabs are lifted by the mounting loops. After the first slab has been laid and leveled, the installation of the next slab begins. The gaps at the joints are sealed polyurethane foam and cement milk.
Anyone who has at least once dealt with the construction of a house knows how important hollow reinforced concrete slabs or floor panels are. Hollow-core concrete floor slabs, in fact, make up about 90% of the total weight of the house. Floor slabs (PC) can vary greatly in both weight and size, depending on the specific purposes for which they are used.
Structural features of hollow core slabs
As you might guess, the inside of reinforced concrete floor slabs (RC) are hollow, which is why they are labeled for sale as multi-hollow. But the holes inside such slabs, contrary to misconception, can have not only oval, but also round, square and other shapes.
Scheme of supporting a hollow core slab However, in most cases, floor slabs (PCs) have cylindrical hollow circles inside.
Interestingly, floor slabs (PC) can be either unreinforced or reinforced. Reinforced concrete floor slabs (PC) will be reinforced.
Such floor slabs (PCS), although they have significantly more weight, which ultimately increases both the load on the building and the cost of construction, however, have a large margin of safety. Installation of floor slabs, namely the installation method itself, depends on what support the slabs will be placed on, because support is also an important criterion.
For example, if the support of the slab is not stable enough, this can lead to unpleasant consequences, which, of course, must be avoided.
Scheme of laying a hollow core slab on the second floor Characteristics of hollow core slabs
Size
Its final cost also depends on the size of the hollow core PC; in addition to parameters such as width and length, weight is also important.
PC sizes vary as follows:
- the length of the PC ranges from 1180 to 9700 millimeters;
- The width of the PC ranges from 990 to 3500 millimeters.
The most popular and in demand are multi-hollow panel slabs, the length of which is 6000 mm and the width is 1500 mm. The height or thickness of the panel is also important (it would be more correct to talk about height, but builders, as a rule, say “thickness”).
So, the thickness that multi-hollow panels can have is always the same value - 220 mm. Great value has, of course, the weight of the floor panel. Concrete slabs the ceiling must be lifted by a crane with a minimum lifting capacity of 4-5 tons.
Comparative table of coordination sizes of hollow core floor slabs The length and weight of the panels are of utmost importance for construction; length is an even less important indicator than weight.
Weight
As for such an important parameter as weight, everything is very clear the first time: the range of products produced in Russia ranges from 960 kilograms to 4.82 tons. Weight is the main criterion by which the method by which the panels will be installed is determined.
Typically, cranes are used, as noted above, with a lifting capacity of at least 5 tons (of course, cranes must lift weight with some margin).
The weight of panels with the same markings may differ, but only slightly: after all, if we consider the weight with an accuracy of one gram, anything can affect it.
Comparative characteristics main brands of hollow core slabs If, for example, a product is caught in the rain, then it will a priori be slightly heavier than the product that was not exposed to rain.
Types of loads
To begin with, it should be noted that any overlap requires the presence of the following 3 parts:
- The upper part, with the floor where people live. Accordingly, the panel will be loaded by the floor covering, various insulating elements and, of course, concrete screeds- main component of the load;
- The lower part, with the presence of the ceiling, its decoration, and lighting fixtures. By the way, you shouldn’t be skeptical about the availability of lighting fixtures. Firstly, the same LED lamps require partial destruction of the plate with a hammer drill to lay the cable. Secondly, if we take large premises, with columns and halls, huge crystal chandeliers can hang there, which will give more load than any other device or type of decoration. This must also be taken into account;
- Structural. It unites both the upper and lower parts at once, as if supporting them in the air.
A hollow core slab is a structural slab that supports both the upper and lower parts of the floor in the air!
By the way, you should not discount the dynamic load. It, as you might guess, is created by people themselves, as well as the things they move. All this affects the properties and states of the panel.
Diagram of a hollow core slab with holes For example, if you once transport a heavy piano in a small two-story house from one place to another is normal, but daily movement will create much more on a multi-hollow slab negative influence. It is unlikely to fall, but there may be serious problems with ventilation later.
Based on the type of load distribution, they are divided into 2 groups:
- distributed;
- point.
To understand the difference between these two types, it is worth giving an example. The same huge crystal chandelier, which weighs one tone - this is a point load. But suspended ceiling with a frame over the entire surface of the slab - this is already a distributed load.
Device technological line for the production of hollow core slabs But there is also a combined load, combining point and distributed. For example, a bathtub filled to the top. The bathtub itself stands on legs, and its pressure on the legs is a type of distributed load. But the legs standing on the floor are already a point load.
Its cost directly depends on the weight of the hollow core slab.
It's complicated, but you can figure it out. And it is necessary! After all, calculations for floors and hollow core slabs during construction will still need to be made.
Brands of hollow core slabs
As a matter of fact, hollow core slabs don’t even have brands as such. We are talking about markings that reflect some parameters. It is enough to give a small example.
Scheme of laying a hollow core slab on a crossbar Let's say the panel has the following markings: PC 15-13-10 PC - means hollow core slab; all digital designations indicate any technical parameters.
15 would mean that the panel is approximately 15 decimeters (1.5 meters) long. Why approximately? It’s just that the length can be 1.498 meters, but on the marking the manufacturer has the right to round this figure to 1.5 meters (15 decimeters). The number 12 means that the product is 10 decimeters wide. Last digit (in in this case- 10) the most important indicator.
This is the load that the material can withstand (maximum permissible). In our case, the maximum load will be 10 kilograms per 1 dm². Usually builders calculate the load per square meter, here it will be 1000 kilograms per 1 m². In general, everything is not so difficult.
The panel brand always looks like PC-XX-XX; if sellers offer other options, then you should be wary.
Load calculation
Calculation of limiting impact
Calculation of the limiting impact is a mandatory condition when designing a building. The dimensions and other parameters of the panels are determined by the old, good Soviet GOST number 9561-91.
Construction of a hollow core slab with a reinforced screed In order to determine the load that will be exerted on the product, it is necessary to indicate on the drawing of the future structure the weight of absolutely all elements that will “press” on the ceiling. Their total weight will be the maximum load.
First of all, you need to consider the weight of the following elements:
- cement-sand screeds;
- gypsum concrete partitions;
- weight of flooring or panels;
- thermal insulation materials.
Subsequently, all the obtained indicators are summed up and divided by the number of panels that will be present in the house. From here you can get the maximum, maximum load on each specific product.
Calculation of optimal load
It is clear that the maximum permissible level is a critical indicator, which cannot be brought to under any circumstances. Therefore, it is best to calculate exactly optimal indicator. For example, a panel weighs 3000 kg. It is needed for an area of 10 m².
It is necessary to divide 3000 by 10. The result is that the maximum permissible load value will be 300 kilograms per 1 m². This is a small indicator, but you also need to take into account the weight of the product itself, for which the load was also calculated (let’s say its value is 800 kilograms per 1 m²). From 800 you need to subtract 300, the result is 500 kilograms per 1 m².
Now you need to roughly estimate how much all the loading elements and objects will weigh. Let this figure be equal to 200 kilograms per 1 m². From the previous indicator (500 kg/m²) you need to subtract the resulting one (200 kg/m²). The result will be a figure of 300 m². But that's not all.
Diagram of a hollow core slab with waterproofing Now from this indicator it is necessary to subtract the weight of furniture, finishing materials, and the weight of people who will constantly be in the room or house. “Live weight” and all elements, their load, let it be 150 kg/m². From 300 you need to subtract 150. As a result, the optimal permissible indicator will be obtained, the designation of which will be 150 kg/m². This will be the optimal load.
Advantages of hollow core slabs
Among the advantages of these products are the following:
- relatively small load on the perimeter of the entire building, in contrast to the same solid products;
- high strength indicators, despite the fact that the panels at the bottom are hollow;
- reliability;
- settlement of the house will be much less intense than when using solid products (in fact, this advantage comes from the relatively low weight);
- relatively low cost.
In general, hollow-core panels are one of the most important building materials. Today it is produced by only a few factories throughout vast Russia. The main thing, as noted above, is not to be deceived when purchasing.
Diagram of the arrangement of reinforcement blocks in a hollow-core floor slab Sometimes (this is rare, but still) sellers try to sell low-quality panels, so-called lightweight ones. For example, they may have markings indicating that the product is designed for a load of 500 kilograms per square meter, but in reality this parameter is several times lower.
This is not even fraud, it is a criminal offense that should be punished to the fullest extent of the law. After all, if you buy a panel designed for a smaller load, there is a serious risk of building collapse. This situation can be observed not only in the provinces, but even in Moscow or St. Petersburg.
In general, you need to be extremely careful when purchasing such products. It is important to remember that any design mistake can even have tragic consequences.
Video
You can watch a video where experts talk in detail about the features various types hollow slabs.
The range of laying reinforced concrete slabs - from the formation of a foundation base for wooden buildings (quick assembly), or separation of the basement from the higher body of the house, to installation attic floor upon completion top floor. Also, in addition to the usual interfloor covering, some types of panels are also used to build walls.
When covering floors, slabs are capable of not only accepting and distributing large loads(the weight of those located on them internal partitions, equipment, furniture, people), but also serve as a reliable element of rigidity in the structure of the entire building.
Products are made from heavy concrete and in addition to increased strength and fire resistance, it has high levels of water and frost resistance, as well as sound insulation. The upper and lower smooth surfaces of the product respectively serve as the floor and ceiling in the room and require minimal interior decoration.
There are several varieties of this building element. Its choice depends on the properties and characteristics of the slab required in each case, its area of application and economic calculations.
Types of slabs (classification)
According to their structural structure, reinforced concrete slabs are of 3 types:
- hollow;
- solid (solid);
- ribbed.
Hollow core slabs
In private construction, hollow core slabs are most often used. Longitudinal round voids lighten the weight of the slab and increase its thermal insulation characteristics and allow you to hide wires in them internal wiring engineering communications.
Due to the popularity and widespread use of floors with longitudinal voids, their production is gradually expanding and modernizing, adapting to the emergence of new materials and construction technologies. I must say that the shape of voids can now be not only round, but also oval and vertical.
There are several brands or varieties of slabs with longitudinal voids:
PC
Widely used since Soviet times - made of heavy concrete, have round voids inside with a diameter of 140 or 159 mm, standard height 220 mm and mounting loops. Which, after laying the floor, serve as an additional embedded part for fastening the slabs together with anchors by welding.
As a rule, in private low-rise construction it is not necessary to fasten the slabs together after installation.
PNO (lightweight)
After some time, such modernization of these structures appeared. The product is thinner (160 mm) and weight. At the same time reinforced with a special method and thicker reinforcement, it can withstand the same loads, like the PC slab.
The use of lightweight products is considered more economical compared to PC boards in several respects:
- the weight of the lightweight floor transfers less load to the foundation, and accordingly, materials are saved when constructing the base of the building;
- the boards themselves are slightly cheaper than traditional PCs due to less material consumption for their manufacture;
- transportation costs during transportation are reduced - a larger number of reinforced concrete products are installed on a transport unit with the same volume and weight as when loading PC slabs.
Attention!
If the ends of the holes in the purchased slabs are not sealed at the factory, it must be done at the production site. construction work- pour concrete mortar(grade M200) in the support area.
This product is made only from heavy concrete. 
Bench panels (PB or PPS)
Reinforced concrete products of the latest generation. Products are manufactured on special stands of various widths using formless molding. This allows us to produce products whose length is not tied to GOST standards. That is, the slab is cut on a production stand for spans, in accordance individual project, in increments of only 10 cm. The height of the structure can also vary from 160 to 300 mm, depending on the required length.
High grade of concrete (M400 - M550) and the placement of pre-stressed lower layers of reinforcement ensure high structural strength in all dimensional options. The only disadvantage of this product can be considered its higher cost compared to PC boards.
It is the bench panels that can be mounted in vertical view- for the construction of walls of frame houses.
Attention!
During production, if a short-size slab is sawed off at the last stand, then due to excessive compression of the prestressed reinforcement, the structure may bend (with the middle bending upwards). This defect is easy to notice during visual inspection, in a stack among other products. And although such cases are quite rare, especially in good producers, and up to certain values, such a deflection is not considered a defect; you should pay attention to this when purchasing.
Other types of slabs
- Solid single-layer (1P, 2P)- most often used in private construction for installation ceiling. Made from cellular concrete- 120 mm thick, and heavy - 160 mm thick.
- Monolithic— if for some reason standard production boards are not suitable for the project, you can produce it yourself. This is a fairly simple, but long and labor-intensive process; it is justified by the possibility of application for a wide variety of forms of coverage areas. It will be necessary to install load-bearing beams, formwork and reinforcing mesh. Pouring concrete (not lower than grade M200) is kept in the formwork for the prescribed 28 days - until the design strength is fully achieved. It is believed that monolithic structures the highest load-bearing capacity if N-grade corrugated sheeting is used when pouring them.
- Ribbed- their design feature is the distribution of thickenings and thinner elements in accordance with compressive and tensile loads. Due to this, high strength and load-bearing capacity of the slab is achieved. The main application is in industrial construction and when installing foundations in high-rise buildings. But sometimes such slabs are found as garage floors. They are not used in residential construction due to the shape of the lower side, which is inconvenient for finishing, having a concave hollow configuration and transverse stiffeners.
Ribbed floor slabs Difference between PC and PB boards
If you have chosen hollow core slabs, let's take a closer look. Let's look at the differences between traditional PC boards and bench panels with formless PB molding.
For convenience, the data is given in the table:
| PC and PNO | PB or PPP | |||
| Thickness | ||||
| PC - 220 mm, lightweight - 160 mm |
from 160 to 300 mm | |||
| Length | ||||
| PC - up to 7.2, sometimes up to 9 m, PNO - up to 6.3 meters, with a step determined by each manufacturer individually |
The maximum length is 12 m, structurally depending on the height of the panel. The slabs are cut to length to order, with a step size of 10 cm. | |||
| Width | ||||
| 1.00; 1.20; 1.50 and 1.80 m | Most often stands are 1.2 m, less often - 1.00 and 1.50 m | |||
| Basically - typical - 800 kgf/m2, but individual production with a load of 1250 is possible | In addition to the standard load of 800, slabs with loads from 300 to 1600 kgf/m2 are produced | |||
| Armature | ||||
| The bottom layer of reinforcement is exposed prestressing only in slabs over 4.2 m long. In shorter products, simple mesh reinforcement is used. | The reinforcement is subjected to prestressing in products of any length. | |||
| Smoothness | ||||
| Because of long term service and wear of equipment, the concrete surface, as a rule, does not have the desired smoothness. | The latest benches and extruder smoothing provide a smoother, more attractive finish, but some minor exceptions are acceptable. | |||
| Concrete grade | ||||
| M200 - M400 | M400 - M550 | |||
| Hole ends | ||||
| Mandatory sealing of the ends of the holes | Not required due to the strength of the concrete grade |
Calculation of the number of slabs and dimensions for a private house
If the construction of private housing is carried out according to an approved project, then the dimensions and number of slabs are pre-calculated by engineers when developing this order. In general, such calculations are made according to the principle “adjusting” the wall layout to the size of the slabs, and not vice versa. But in private construction anything can happen. And if the walls are already planned or even ready and waiting to be covered, then their number and dimensions need to be calculated, taking into account certain rules:
- the length of the plate is equal to the distance between load-bearing walls plus the width of the area where the slab is supported on the wall (beam);
- The width of the slab is selected based on how many pieces from the assortment you have chosen will cover the transverse distance between the main walls (partitions are not taken into account). The long side of the hollow core slab is laid flush against non-load-bearing walls, or overlapped by no more than 100 mm (to the first void). For more details, see the article about;
- if there is a small gap between the slabs or there is a small area of the room that does not fit into the configuration of the slabs, it can be “closed” by partial monolithic filling, using formwork and reinforcement;
It is better to order products of “non-marketable” sizes in advance, since waiting for their production takes more time than the production of standard designs.
Attention!
In winter, floor slabs are noticeably cheaper. But the area for unloading them needs to be prepared and leveled in the fall. You will also have to order a tractor to clear snow on the site and, possibly, on the driveways. But in the end there will still be savings.
Standard slab sizes
Still, if possible, it is better to use slabs standard sizes, since their acquisition costs much less and takes less time.
At factories, the size ranges of the latest generation of products vary somewhat, but there are size restrictions generally accepted by standards and specifications:
| Type of plate | Length (m) | Width (m) |
| PC, round voids with a diameter of 140 mm | 1,8 / 2,4 / 3,0 / 6,0 | from 1.2 all sizes are multiples of 0.3 m |
| PC, round voids with a diameter of 159 mm and PB slabs |
2,4 / 3,0 / 3,6 / 4,2 / 4,8 /
5,1 / 6,0 / 6,3 / 6,6 / 7,2 sometimes 9.0 |
from 1.0 onwards all sizes are multiples of 0.3 m |
| PNO height 160 mm | from 1.6 to 6.3, sometimes 9.0 | 0,64 / 0,84 / 1,0 / 1,2 / 1,5 |
| teaching staff | from 3 to 12, in 0.1 m increments | 1,0 / 1,2 / 1,5 |
| solid 120 mm high | 3,0 / 3,6 | 4,8 / 5,4 / 6,0 / 6,6 |
| solid 160 mm high | 2,4 / 3,0 / 3,6 | 2,4 / 3,0 / 3,6 / 4,8 / 5,4 / 6,0 |
| ribbed, height 30 mm | 6,0 | 1,5 |
Weight
It is important to know the weight of the slabs when calculating structures. But this is the concern of the designer who draws up the project for the house. It is useful for a private developer to know the weight of the slabs when delivering them to the site and installing them.
In the first case, it is necessary to select the carrying capacity of the transport. Most likely, two vehicles will be needed for delivery.
Used for installation of slabs crane, when ordering you will also be asked about the weight and dimensions of the slabs. Each crane has its own lifting capacity. Since the weight range of the slabs is from 960-4800 kg, a 5-ton truck is enough in any case.
Depending on the concrete used, the mass of a standard 6x1.5 m hollow core slab varies from 2.8 to 3.0 tons.
Since slabs with a thickness of 160 mm and 220 mm are most common in private construction, we give their weight by linear meter for slab width 1500 mm: 
Here are some more standard slabs: 
Marking of slabs
According to GOST, all types of slabs have their own standards. Their observance is necessary when designing objects and during installation calculations. Each slab is marked with a special encrypted inscription that reflects not only overall dimensions products, but also its main strength and design characteristics. Having understood the meanings of one brand of slabs, you can easily read the others, regardless of whether the slab sizes are standard or custom-made.
The first letters in the specification indicate the type of construction (PC, PNO, PB, PPS). Next, through a hyphen, there is a listing of the length and width values (in decimeters, rounded to a whole number), and again through a hyphen - the maximum permissible weight load on the structure, in centners per m 2, without taking into account its own weight (only the weight of partitions, interior decoration, furniture , equipment, people). At the end, a letter addition is possible, indicating additional reinforcement and type of concrete (t - heavy, l - light, i - cellular) 
Let's look at an example and decipher the markings. Slab Specification PK-60-15-8AtVt means:
- PC – slab with round voids;
- 60 – length 6 m (60 dm);
- 15 – width 1.5 m (15 dm);
- 8 – the structure can be mechanically loaded up to 800 kg per m2;
- AtV - presence of additional reinforcement (AtV class)
- t - made of heavy concrete.
The height of the product is not indicated, because refers to the standard size of this product (220 mm).
Also, the letters in the markings inform:
- PC - standard slab with round voids,
- NV – single-row reinforcement;
- NKV – double-row reinforcement;
- 4НВК – four-row reinforcement.
Useful video
A representative of one of the factories talks about the size of their products:
This article is for informational purposes and provides a general overview of reinforced concrete floors. Considering the impressive weight of structures, when using them, it is desirable to have an engineering calculation of foundations and load-bearing walls, taking into account the required safety margin.
This standard applies to reinforced concrete hollow-core slabs (hereinafter referred to as slabs), made from heavy, light and dense silicate concrete and intended for the load-bearing part of the floors of buildings and structures for various purposes.
The slabs are used in accordance with the instructions of the working drawings of the slabs and additional requirements specified when ordering these structures.
It is allowed, by agreement between the manufacturer and the consumer, to produce slabs that differ in types and sizes from those given in this standard, subject to the remaining requirements of this standard.
Plates are divided into types:
1pc - 220 mm thick with round voids with a diameter of 159 mm. designed to be supported on two sides;
1PKT - the same, for support on three sides;
1PKK - the same, for support on four sides;
2PK - 220 mm thick with round voids with a diameter of 140 mm, designed for support on two sides;
2PKT - the same, for support on three sides;
2PKK - the same for support on four sides;
3PK - 220 mm thick with round voids with a diameter of 127 mm, designed for support on two sides;
3PKT - the same, for support on three sides;
3PKK - the same, for support on four sides;
4PK - 260 mm thick with round voids with a diameter of 159 mm and cutouts in the upper zone along the contour, intended for support on both sides;
5PK - 260 mm thick with round voids with a diameter of 180 mm, designed for support on two sides;
6PK - 300 mm thick with round voids with a diameter of 203 mm, designed for support on two sides;
7PK - 160 mm thick with round voids with a diameter of 114 mm, designed for support on two sides;
PG - 260 mm thick with pear-shaped voids, designed for support on two sides;
PB - 220 mm thick, manufactured by continuous molding on long stands and designed to be supported on two sides.
Table 19
|
Slab type |
Reduced slab thickness, m |
Average density of concrete slab, kg/m 3 |
Slab length, m |
Characteristics of buildings (structures) |
|
Up to 7.2 incl. |
Residential buildings in which the required sound insulation of residential premises is ensured by the installation of hollow-core, floating, hollow-core layered floors, as well as single-layer floors on a leveling screed |
|||
|
Up to 9.0 incl. | ||||
|
Up to 7.2 incl. |
Residential buildings in which the required sound insulation of residential premises is ensured by installing single-layer floors |
|||
|
Up to 6.3 incl. |
Residential large-panel buildings of the 135 series, in which the required sound insulation of the premises is ensured by installing single-layer floors |
|||
|
Up to 9.0 incl. |
Public and industrial buildings (structures) |
|||
|
Up to 12.0 incl. |
||||
|
Up to 7.2 incl. |
Low-rise and estate-type residential buildings |
Explanations for the table. 19
|
Term |
Explanation |
|
Single layer floor |
A floor consisting of a covering (linoleum on a heat- and sound-insulating basis) laid directly on the floor slabs or on a leveling screed |
|
Single-layer floor on a leveling screed |
A floor consisting of a covering (linoleum on a heat- and sound-insulating basis) laid on a leveling screed |
|
Hollow floor |
A floor consisting of a hard covering along joists and soundproofing pads laid on floor slabs |
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Voidless layered floor |
A floor consisting of a hard surface and a thin soundproofing layer, laid directly on the floor slabs or on a leveling screed |
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Floating floor |
A floor consisting of a covering, a rigid base in the form of a monolithic or prefabricated screed and a continuous soundproofing layer of elastic-soft or bulk materials laid on floor slabs |
The shape and coordination length and width of the slabs (except for PB type slabs) must correspond to those given in table. 20 and to hell. 9-11. For buildings (structures) with a calculated seismicity of 7 points or more, it is allowed to manufacture slabs having a shape different from that indicated in the drawing. 9-11.
The structural length and width of the slabs (except for PB type slabs) should be taken equal to the corresponding coordination size (Table 20), reduced by the value a1 (the gap between adjacent slabs) or a2 (the distance between adjacent slabs if there is a separating element between them, for example, antiseismic belts, ventilation ducts, crossbar ribs), or increased by the value of a3 (for example, for slabs supported by the entire thickness of the staircase walls of buildings with transverse load-bearing walls). The values of a1, a2 and a3 are given in table. 21.
The shape and dimensions of PB type slabs must correspond to those established in the working drawings of the slabs, developed in accordance with the parameters of the molding equipment of the manufacturer of these slabs.
Table 20
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slabs |
Plate drawing number |
Coordination dimensions of the slab, mm |
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Length |
Width |
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From 2400 to 6600 inclusive. at intervals of 300, 7200, 7500 |
1000, 1200, 1500, 1800, 2400, 3000, 3600 |
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1000, 1200, 1500 |
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From 3600 to 6600 inclusive. at intervals of 300, 7200, 7500 |
From 2400 to 3600 inclusive. at intervals of 300 |
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From 2400 to 3600 inclusive. at intervals of 300 |
From 4800 to 6600 inclusive. at intervals of 300, 7200 |
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From 2400 to 6600 inclusive. at intervals of 300, 7200, 9000 |
1000, 1200, 1500 |
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6000, 9000, 12000 |
1000, 1200, 1500 |
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1000, 1200, 1500 |
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From 3600 to 6300 inclusive. at intervals of 3000 |
1000, 1200, 1500, 1800 |
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6000, 9000, 12000 |
1000, 1200, 1500 |
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Note. The length of the slabs is taken to be:
the size of the side of the slab not supported by the load-bearing structures of the building (structure) - for slabs intended to be supported on two or three sides;
the smaller size of the slab in plan - for slabs intended to be supported along the contour.
Plates of types 1PKT, 2PKT, 3PKT, 5PK, 6PK, 7PKT slabs of types 1PKT, 2PKT, 3PKT
1 – 1 1 – 1
P 
casts of types 1PKK, 2PKK, 3PKK
2
–2
Crap. 10. 4pc type plate
1
–1 2–2
Crap. 11. Plate type PG
1
–1 2–2
Notes to hell 9-11
1. Slabs of types 1PKT, 2PKT, 3PKT, 1PKK, 2PKK and 3PKK can have technological bevels along all side faces.
2. Methods for strengthening the ends of the slabs are shown in Fig. 9-11 as an example. It is allowed to use other methods of reinforcement, including reducing the diameter of the voids through one on both supports without sealing the opposite ends of the voids.
3. The dimensions and shape of the groove along the longitudinal upper edge of slabs of types 1PKT, 2PKT and 3PKT (Drawing 9b) and along the contour of slabs of type 4PK (Drawing 10) are established in the working drawings of the slabs.
4. In slabs intended for buildings (structures) with a design seismicity of 7-9 points, extreme voids may be absent due to the need to install embedded products or produce reinforcement for connections between slabs, walls, and anti-seismic belts.
Table 21
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Scope of application of plates |
Additional dimensions taken into account when determining design size slabs, mm |
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length |
widthA 1 |
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A 1 |
A 2 |
A 3 |
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Large-panel buildings, including buildings with a calculated seismicity of 7-9 points Buildings (structures) with walls made of bricks, stones and blocks, with the exception of buildings (structures) with a calculated seismicity of 7-9 points Buildings (structures) with walls made of bricks, stones and blocks with a calculated seismicity of 7-9 points Frame buildings (structures), including buildings (structures) with a calculated seismicity of 7-9 points |
10 - for slabs with a coordination width of less than 2400. 20 - for slabs with a coordination width of 2400 or more |
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Voids in slabs intended to be supported on two or three sides should be located parallel to the direction in which the length of the slabs is determined. In slabs intended to be supported on four sides, the voids should be located parallel to any side of the slab contour.
The nominal distance between the centers of voids in slabs (except for slabs of types PG and PB) should be taken as no less than, mm:
185-in slabs of types 1PK, 1PKT, 1PKK, 2PK, 2PKT, 2PKK, 3PK, 3PKT, 3PKK and 4PK;
235 in slabs of type 5PK;
233 " " " 6pcs;
139 « « « 7pcs.
The distance between the centers of the voids of slabs of types PG and PB is determined in accordance with the parameters of the molding equipment of the manufacturer of these slabs.
The slabs should be made with recesses or grooves on the side faces to form, after embedding, intermittent or continuous keys that ensure the joint operation of the floor slabs for shear in the horizontal and vertical directions.
By agreement between the manufacturer and the consumer and the design organization - the author of the project for a specific building (structure), it is allowed to produce slabs without recesses or grooves for the formation of keys.
The slabs should be made with reinforced ends. Strengthening the ends is achieved by reducing the cross-section of the voids on the supports or filling the voids with concrete or concrete liners (Fig. 9-11). When the design load on the ends of the slabs in the wall support zone does not exceed 1.67 MPa (17 kgf/cm 2), it is allowed according to upon agreement between the manufacturer and the consumer, supply slabs with unreinforced ends.
Methods of strengthening and minimum dimensions seals are established in working drawings or indicated when ordering slabs.
The slabs are designated by marks in accordance with the requirements of GOST 23009. The slab mark consists of alphanumeric groups separated by hyphens.
In the first group, indicate the designation of the slab type, the length and width of the slab in decimeters, the values of which are rounded to the nearest whole number.
In the second group indicate:
design load on the slab in kilopascals (kilogram-force per square meter) or the serial number of the slab according to bearing capacity;
steel class of prestressed reinforcement (for prestressed slabs);
type of concrete ( L - lightweight concrete, C-dense silicate concrete; heavy concrete is not indicated).
In the third group, if necessary, additional characteristics are indicated that reflect the special conditions of use of the slabs (for example, their resistance to aggressive gaseous media, seismic influences), as well as designations design features slabs (for example, the presence of additional embedded products).
An example of a symbol (brand) of a 1PK type slab with a length of 6280 mm, a width of 1490 mm, designed for a design load of 6 kPa, made of lightweight concrete with prestressed reinforcement of class At-V:
1PK63.15-6A T VL
The same, made of heavy concrete and intended for use in buildings with a calculated seismicity of 7 points:
1PK63.15-6A T V-C7
Slabs should be made of heavy concrete in accordance with GOST 26633, structural lightweight concrete of a dense structure with an average density of at least 1400 kg/m 3 in accordance with GOST 25820, or dense silicate concrete with an average density of at least 1800 kg/m 3 in accordance with GOST 25214 classes or grades of compressive strength specified in the working conditions drawings of these plates.
If you have at least once encountered the construction process or carried out apartment renovations, then you should know what hollow-core floor slabs are. Their importance is difficult to overestimate. Design features, its main characteristics and markings are taken into account during the work process. This knowledge allows you to determine what the limit of useful and decorative loads the slab can withstand.
Dimensions and weight
The size and type of the product affect its final price. The length of the described slabs can be equal to the limit from 1.18 to 9.7 m. As for the width, it is limited to a value from 0.99 to 3.5 m.
The most popular are those products whose length is 6 m, while their width usually reaches a maximum of 1.5 m. The minimum value is 1.2 m. Getting acquainted with the dimensions of hollow core slabs, you can understand that their thickness remains unchanged and is equal to 22 cm. Given the impressive weight of such structures, an assembly crane is usually used for their installation; its capacity should be 5 tons.
Types of loads on reinforced concrete structures
Any overlap in the structure has three parts, among them:
- top;
- lower;
- structural.
The first is where the residential floor above is located. This includes flooring, insulation materials and screeds. The bottom is the surface non-residential premises. This includes hanging elements and ceiling finishes. As for the structural part, it combines the above and holds them in the air.
Hollow core slabs ceilings serve as a structural part. A constant static load is exerted on it finishing materials, used in the design of ceilings and floors. This means elements suspended from the ceiling and installed on top of it, namely:
- punching bags;
- suspended ceilings;
- chandeliers;
- partitions;
- baths.
In addition, you can also highlight dynamic load. It is caused by objects moving on the surface. In this case, one should take into account not only the mass of a person, but also domestic animals, which today are quite exotic (tigers, lynxes, etc.).
Distributed and point types of loads
The above types of loads can be applied to hollow core floor slabs. A point punch, for example, is an impressively sized punching bag suspended from the ceiling. As for the suspension system, it interacts with the suspensions at regular intervals with a frame and exerts a distributed load.
These two types of load can have a complex effect. In this case, the calculation will be more complicated. If you install a bathtub that holds 500 liters, then you should take into account two types of load. The filled container is distributed on the surface of the support between the points of contact. There is also a point load, which is applied to each leg individually.
Calculation of permissible loads
The load on hollow core slabs can be calculated by you. These manipulations are carried out in order to find out how much the product can bear. Afterwards it is necessary to determine what the ceiling will bear. This should include partitions, materials based on insulation layers, parquet flooring and cement screeds.
The total weight of the load must be divided by the number of slabs. Roof supports and load-bearing supports should be located at the ends. The internal parts are reinforced in such a way that the load is applied to the ends. The central part of the slab is not capable of supporting the weight of serious structures. This is true even if there are main walls or support columns below. Now you can calculate the load on the hollow core slab. To do this, you need to find out its weight. If we take a product marked PK-60-15-8, then we can say that its weight is 2850 kg. It is manufactured according to state standards 9561-91.
The first step is to determine the area of the bearing surface of the product; it is 9 m2. To do this, 6 must be multiplied by 1.5. Now you can find out how many kilograms of load this surface can bear. Why do you need to multiply the area by permissible load per one square meter. As a result, you will be able to get 7200 kg (9 m2 multiplied by 800 kg per m2). From here you should subtract the mass of the plate itself and then you will be able to get 4350 kg.
Then you need to calculate how many kilograms the floor insulation will add, floor coverings and screed. Usually in work they try to use such a volume of solution and thermal insulation so that the materials together do not weigh more than 150 kg/m2. With a surface area of 9 m2, the hollow core slab will carry 1350 kg. This value can be obtained by multiplying by 150 kg/m2. This number should be subtracted from the previously obtained figure (4350 kg). Which will ultimately allow you to get 3000 kg. Recalculating this value per square meter, you get 333 kg/m2.
According to sanitary standards and rules, a weight of 150 kg/m2 should be allocated to static and dynamic loads. The remaining 183 kg/m2 can be used for installation decorative elements and partitions. If the weight of the latter exceeds the calculated value, then it is recommended to choose a lighter floor covering.
State standards and technical requirements
For large-panel buildings for various purposes Hollow core slabs must be used. They are manufactured according to the above state standard and can be based on the following materials:
- lightweight concrete;
- silicate concrete;
- heavy concrete.
The manufacturing technology, which involves the presence of voids, provides structures with excellent sound insulation properties and low weight. They are ready to serve long time and have good strength characteristics, which are due to the use of steel ropes and reinforcement.
When installed, such products are located on load-bearing structures. Round voids can have a diameter of up to 159 mm. The dimensions of hollow core slabs are one of the factors by which products are classified. The length can reach 9.2 m. As for the width, the minimum is 1 m and the maximum is 1.8 m.
The class of concrete used corresponds to B22.5. Density is equal to the limit from 2000 to 2400 kg/m 3. State standards also specify the grade of concrete taking into account frost resistance, it looks like this: F200. Hollow slabs (GOST 9561-91) are made of concrete with a strength within 261.9 kg/cm 2.
Brands of hollow core slabs
Reinforced concrete products cast in a factory are subject to marking. It is encoded information. The slabs are designated by two capital letters PC. This abbreviation is next to the number that indicates the length of the product in decimeters. Next are the numbers indicating the width. The last indicator indicates how much weight in kilograms 1 dm2 can withstand, taking into account its own weight.
For example, a reinforced concrete hollow core slab PK 12-10-8 is a product with a length of 12 dm, which is 1.18 m. The width of such a slab is 0.99 m (approximately 10 dm). The maximum load per 1 dm2 is 8 kg, which is equal to 800 kg per square meter. In general, this value is the same for almost all hollow core slabs. As an exception, there are products that can withstand up to 1250 kg per square meter. You can recognize such slabs by their markings, at the end of which there are numbers 10 or 12.5.
Cost of slabs
Interfloor hollow core slabs are manufactured using conventional or prestressed reinforcement. In addition to load-bearing capacity, panels must also meet sound insulation requirements. For this purpose, the product is provided with holes, which can have a round or other cross-section. Such structures belong to the third category of crack resistance.
In addition to these characteristics, you may also be interested in the cost. You will have to pay 3,469 rubles for a hollow core slab weighing 0.49 tons. In this case we are talking about a product with the following dimensions: 1680x990x220 mm. If the weight of the slab increases to 0.65 tons, and the dimensions become 1680x1490x220 mm, then you will have to pay 4351 rubles. The thickness of the hollow core slab remains unchanged, which cannot be said about the other parameters. For example, you can purchase a product with dimensions equal to 1880x990x220 mm for 3,473 rubles.
For reference
If the floor slab is manufactured at the factory, then in the process they are used state standards. They guarantee high quality products and compliance with hardening time and temperature conditions. The solid type of slab is distinguished by its impressive weight and, accordingly, high cost. This explains the fact that such products are most often used in the construction of important buildings.
In conclusion
Floor slabs have found their popularity and are widely used in construction residential buildings and are lighter in weight compared to solid slabs, and they are cheaper. But in matters of reliability and strength they are not inferior. The location of voids and their number do not in any way affect the load-bearing properties of the slab. In addition, they allow you to achieve higher sound and thermal insulation properties buildings.
But no matter how light they are considered, their installation cannot be done without appropriate lifting equipment. This allows you to increase the accuracy of installation and complete construction in a shorter time. These products are also good because they are manufactured in a factory, which means they undergo quality control.
