Bearing capacity of hollow core floor slabs GOST. Multi-hollow reinforced concrete floor slabs. Hollow core marking

If you have at least once encountered the construction process or repaired an apartment, then you should be aware of what hollow-core floor slabs are. Their importance is difficult to overestimate. Design features, its main characteristics and markings are taken into account in the process of work. This knowledge allows us to determine what is the limit of useful and decorative loads that the plate can withstand.

Dimensions and weight

The size and type of the product affect its final price. In length, 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 1.5 m maximum. 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, a mounting crane is usually used to install them, its capacity should be 5 tons.

Types of loads on a reinforced concrete structure

Any overlap in the structure has three parts, among them:

• top;
• lower;
• structural.

The first is where the residential floor is located above. This includes flooring, insulation materials and screeds. The lower part is the surface of non-residential premises. It includes hanging elements and ceiling finishes. As for the structural part, it combines the above and keeps them in the air.

Hollow core slabs play the role of a structural part. A constant static load is exerted on it by finishing materials used in the design of the ceiling and floor. This refers to elements suspended from the ceiling and installed on top of it, namely:

• punching bags;
• dropped ceilings;
• chandeliers;
• partitions;
• baths.

In addition, you can also highlight the dynamic load. It is provided 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 slabs. Point, for example, is a punching bag of impressive size, suspended from the ceiling. As for the suspension system, it interacts with the suspensions through the frame at regular intervals and exerts a distributed load.

These two types of load can act in combination. In this case, the calculation will be more complicated. If you install a bath that holds 500 liters, then two types of load should be taken into account. The filled container exerts a distributed effect on the surface of the support between the points of contact. There is also a point load, which turns out to be each leg individually.

Calculation of allowable 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 endure. After that, it is necessary to determine what the overlap will bear. This should include partitions, materials at the base of insulating layers, parquet flooring and cement screeds.

The total weight of the load must be divided by the number of plates. Supports for the roof and load-bearing supports should be located at the ends. The internal parts are reinforced in such a way that the load is on the ends. The central part of the slab is not able to take the weight of serious structures. This is true even if there are main walls or supporting columns below. Now you can calculate the load on the hollow slab. To do this, you need to know its weight. If we take a product marked PK-60-15-8, then it can be argued that its weight is 2850 kg. It is manufactured according to state standards 9561-91.

First of all, it is necessary to determine what is the area of ​​​​the bearing surface of the product, it is 9 m 2. To do this, 6 must be multiplied by 1.5. Now you can find out how many kilograms of load this surface can bear. For which the area must be multiplied by the allowable load per square meter. As a result, it will be possible to get 7200 kg (9 m 2 times 800 kg per m 2). From here it is necessary to subtract the mass of the plate itself and then it will be possible to obtain 4350 kg.

After that, you need to calculate how many kilograms the floor insulation, floor coverings and screed will add. Usually, they try to use such a volume of mortar and thermal insulation in their work that the materials together do not weigh more than 150 kg / m 2. With 9 m 2 of surface, a hollow slab will carry 1350 kg. This value can be obtained by multiplying by 150 kg/m 2 . This number should be subtracted from the previously obtained figure (4350 kg). Which in the end will allow you to get 3000 kg. Recalculating this value per square meter, you get 333 kg / m 2.

According to sanitary norms and rules, a weight of 150 kg / m 2 must be allocated to static and dynamic loads. The remaining 183 kg / m 2 can be used to install decorative elements and partitions. If the weight of the latter exceeds the calculated value, then it is recommended to prefer a lighter floor covering.

State standards and technical requirements

Hollow-core slabs are necessarily used for large-panel buildings for various purposes. 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 provides for the presence of voids, provides structures with excellent soundproofing properties and low weight. They are ready to serve for a long time and have good strength characteristics, which are due to the use of steel ropes and fittings.

During installation, such products are located on load-bearing structures. Round voids may have a diameter within 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. The density is equal to the limit from 2000 to 2400 kg/m 3 . The state standards also spell out the brand of concrete, taking into account frost resistance, it looks like this: F200. Hollow slabs (GOST 9561-91) are made of concrete with a strength of 261.9 kg/cm2.

Hollow core grades

Reinforced concrete products cast in a factory are subject to marking. It is coded information. Plates are designated by two capital letters PC. This abbreviation stands next to the number that indicates the length of the product in decimeters. Next come the numbers indicating the width. The last indicator indicates how much weight in kilograms 1 dm 2 can withstand, taking into account its own weight.

For example, a reinforced concrete hollow 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 (about 10 dm). The maximum load per 1 dm 2 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 plates by marking, at the end of which there are numbers 10 or 12.5.

The cost of plates

Interfloor hollow core slabs are manufactured using conventional or prestressed reinforcement. Panels, in addition to bearing capacity, must also meet the requirements of sound insulation. For this product, holes are provided, which may 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 3469 rubles for a hollow slab, the weight of which is 0.49 tons. In this case, we are talking about a product with the following dimensions: 1680x990x220 mm. If the weight of the plate increases to 0.65 tons, and the dimensions become equal to 1680x1490x220 mm, then you will have to pay 4351 rubles. The thickness of the hollow 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 3473 rubles.

For reference

If the floor slab is manufactured at the factory, then state standards are used in the process. They guarantee the high quality of the product and compliance with the hardening time and temperature conditions. The full-bodied variety of the plate is distinguished by its impressive weight, respectively, the high cost. This explains the fact that such products are most often used in the construction of important buildings.

Finally

Floor slabs have found their popularity and have become widespread in the construction of residential buildings and are lighter in comparison with solid slabs, and they are cheaper. But in matters of reliability and durability they are not inferior. The location of the voids and their number do not affect the bearing properties of the slab. In addition, they allow you to achieve higher sound and heat insulation properties of the structure.

But no matter how light they are considered, when installing them, you can’t do without the 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 made in a factory, which means they pass quality control.

INTERSTATE COUNCIL FOR STANDARDIZATION. METROLOGY AND CERTIFICATION

INTERSTATE COUNCIL FOR STANDARDIZATION, METROLOGY AND CERTIFICATION

INTERSTATE

STANDARD

REINFORCED CONCRETE FLOOR SLABS

FOR RESIDENTIAL BUILDINGS

Types and basic parameters

Official edition

Standartinform

Foreword

The goals, basic principles and basic procedure for carrying out work on interstate standardization are established by GOST 1.0-92 “Interstate standardization system. Basic Provisions” and GOST 1.2-2009 “Interstate Standardization System. Interstate standards, rules and recommendations for interstate standardization. Rules for the development, adoption, application, updating and cancellation "

About the standard

1 DEVELOPED by Joint-Stock Company TsNIIEP Zhilya - Institute for the Integrated Design of Residential and Public Buildings (JSC TsNIIEP Zhilya)

2 INTRODUCED by the Technical Committee for Standardization TC 465 "Construction"

3 ADOPTED by the Interstate Council for Standardization, Metrology and Certification (Minutes of November 12, 2015 No. 82-P)

4 By order of the Federal Agency for Technical Regulation and Metrology dated November 30, 2015 No. 2077-st, the interstate standard GOST 26434-2015 was put into effect as the national standard of the Russian Federation from January 1, 2017.

5 INSTEAD OF 26434-65

Information about changes to this standard is published in the annual information index "National Standards". and the text of changes and amendments - in the monthly information index "National Standards". In case of revision (replacement) or cancellation of this standard, a corresponding notice will be published in the monthly information index "National Standards". Relevant information, notification and texts are also posted in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology and the Internet

© Standartinform. 2016

In the Russian Federation, this standard cannot be fully or partially reproduced, replicated and distributed as an official publication without the permission of the Federal Agency for Technical Regulation and Metrology

INTERSTATE STANDARD

REINFORCED CONCRETE FLOOR SLABS FOR RESIDENTIAL BUILDINGS Types and main parameters

Reinforced concrete panels for floors in residential buftdings. Types and basic parameters

Introduction date - 2017-01-01

1 area of ​​use

This standard establishes the types, basic dimensions and parameters of floor slabs, general technical requirements for them.

This standard applies to prefabricated reinforced concrete floor slabs made from structural heavy and lightweight concrete (hereinafter referred to as slabs) and intended for the bearing part of floors of residential buildings.

The requirements of this standard should be taken into account when developing regulatory documents and working documentation for slabs of specific types.

2 Normative references

8 of this standard, normative references to the following interstate standards are used:

GOST 13015-2012 Concrete and reinforced concrete products for construction. General technical requirements. Rules for acceptance, labeling, transportation and storage

GOST 21779-82 System for ensuring the accuracy of geometric parameters in construction. Technological approvals

GOST 23009*78 Concrete and reinforced concrete prefabricated structures and products. Symbols (brands)

GOST 26433.0*85 System for ensuring the accuracy of geometric parameters in construction. Rules for performing measurements. General provisions

Note - When using this standard, it is advisable to check the validity of reference standards in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet or according to the annual information index "National Standards", which was published as of January 1 of the current year, and on issues of the monthly information index "National Standards" for the current year. If the reference standard is replaced (modified), then when using this standard, you should be guided by the replacing (modified) standard. If the referenced standard is canceled without replacement, the provision in which the reference to it is given applies to the extent that this reference is not affected.

3 Terms and definitions

8 of this standard, the following terms are used with their respective definitions:

3.1 plate: A large-sized flat element of a building structure that performs load-bearing, enclosing or combined - load-bearing and enclosing, heat engineering, soundproofing functions.

3.2 floor

3.3 coordination (nominal) size of the slab: The design size of the slab between the center (coordination) axes of the building in the horizontal direction.

3.4 structural size of the slab: The design size of the slab, which differs from the constructive (nominal) size by a normalized gap, taking into account mounting and manufacturing tolerances.

Official edition

4 Types, basic parameters and dimensions

4.1 Plates are divided into the following types:

Solid single layer:

1P - plates 120 mm thick.

2P - plates 160 mm thick;

Multi-hollow:

1 PC - slabs 220 mm thick with round voids 159 mm in diameter.

2pcs - slabs 220 mm thick with round voids 140 mm in diameter.

PB - slabs with a thickness of 220 mm of bee-formwork molding.

Slabs of types 2P and 2PK are made only from heavy concrete.

The shape and dimensions of voids in PB-type slabs are established by standards or specifications for slabs of this type.

4.2 Plates of types 1P. 2P i. subject to bench molding. 1PC, 2PC can be provided for support on two or three sides or along the contour. PB-type slabs are designed for support on two sides.

4.3 8 residential buildings with built-in or attached public premises for the floors of these rooms, it is allowed to use slabs of types and sizes established for floors of public buildings.

4.4 The coordination length and width of the slabs must correspond to those indicated in Table 1.

Table 1

Plate size	Coordination dimensions of the plate, mm		Plate weight (reference), t
	Plates type 1P
Plates type 2P
	Plate types

Table 1 continued

Plate size	Cooodination	oeemeoy plates, mm	Plate weight (reference), t

End of table 1

Plate size	Cooodination	plate dimensions, mm	Plate weight (reference), t

Notes

1 For slabs of type 2PK and PB, in the size designation given in this table, replace 1PK with 2PK or PB.

2 If there are plates of the same size, differing in reinforcement in order to be supported on two, three sides or along the contour, an additional designation should be entered into the marking.

3 Coordination length - 9000 mm is applicable only for slabs of type 1 PC.

4 The weight of the slabs is given for slabs of medium density heavy concrete 2500 kg/m 1 .

5 The direction of the calculated span of slabs of type 1PK is set parallel) to the length or width of the slab.

4.5 The slabs in the floor of the building should be located in such a way that their coordination length is equal to the corresponding transverse or longitudinal step of the supporting structures of the building, indicated in Figure 1.

8 cases when paired coordination axes are used in internal load-bearing walls with a thickness of 300 mm or more (replaced in the design documentation by one center axis), the coordination length of the slab should be equal to the distance between the center axes of the building minus the coordination size of the insert or half of the coordination size of the insert indicated on figure 2.

to = L 0 h s Vo

A>. plate coordination length; and. the distance between the transverse and longitudinal coordination axes of the building, respectively

Picture 1

1 - coordination axes of the building; 2 - center axis of the building; a - the distance between the paired

coordination axes; A) - coordination length of the plate; Ai and - the distance between the transverse and longitudinal coordination axes of the building, respectively; L "and B" - the distance between the transverse and longitudinal centering axes of the building, respectively

Figure 2

4.6 The structural length and width of the plates should be taken equal to the corresponding coordination dimensions indicated in Figures 1.2 and Table 1, reduced by the size of the gap between adjacent plates - ai indicated in Table 2.

If there are separating elements at the junction of plates, the geometric axes of which are aligned with the coordination axes (for example, monolithic anti-seismic belts, ventilation ducts, etc.). the structural length of the plates should be taken equal to the corresponding coordination size indicated in Figures 1. 2 and in Table 1. reduced by the size of the gap of the separating element - Og. indicated in table 2.

4.7 The shape and dimensions of PB-type slabs must comply with the established working drawings of the slabs, developed in accordance with the parameters of the molding equipment of the manufacturer of these slabs.

4.8 Additional dimensions taken into account when determining the structural dimensions of the slab are given in Table 2.

table 2

Scope of the plate	Additional dimensions taken into account when determining the structural size of the slab, mm
Large-panel buildings, including buildings with a design seismicity of 7-9 points "				10 - for slabs with coordination width less than 2400: 20 - for slabs with a coordination width of 2400 or more
Buildings with walls made of bricks, stones and blocks, with the exception of buildings with an estimated seismicity of 7-9 points
Buildings with walls made of bricks, stones and blocks with an estimated seismicity of 7-9 points
Frame buildings, including buildings with a design seismicity of 7-9 points

4.9 In the case of a slab covering a space that exceeds the distance between adjacent coordination axes of a building (for example, for a slab supported on the entire thickness of the staircase wall in large-panel buildings with transverse load-bearing walls, etc.), the structural length should be taken equal to the corresponding coordination length, indicated in table 1 and increased by size - az. indicated in table 2.

5 Technical requirements

5.1 Slabs, depending on their location in the floor of the building, are used for calculated uniformly distributed loads (excluding the own weight of the slabs) equal to 3.0; 4.5; 6.0; 8.0 kPa (respectively 300.450, 600. 800 kgf / m 2).

5.2 On the working drawings of the slabs used in a particular building, indicate the location of embedded parts, reinforcement outlets, local cuts, holes and other structural details.

5.3 Consumption rates of concrete and steel of the slab must correspond to those indicated on the working drawings, taking into account possible clarifications made by the design organization in the prescribed manner.

5.4 The slabs must provide a fire resistance limit in accordance with the requirements of the current regulatory documents and technical documentation 4, depending on the required fire resistance of the building.

The fire resistance limit of the plates is indicated on the working drawings.

5.5 The accuracy of the linear dimensions of the plates should be taken according to the fifth or sixth accuracy class in accordance with GOST 21779, taking into account the provisions of GOST 26433.0.

Outside the territory of the Russian Federation, SP 112.13330.2012 "SNiP 21.01-97 Fire safety of buildings and structures" is in force.

Requirements for the quality of concrete surfaces and the appearance of the slabs are established in accordance with GOST 13015 and must be recorded in the manufacturing order.

5.6 Indices of airborne noise insulation of slabs and the reduced level of impact noise under the slab, taken into account when determining the sound insulation indicators of the floor, taking into account the current regulatory documents and technical documentation 2, are given in table 3.

T table3_

	Average density of concrete slab, kg/m*		Index value. dB
			airborne sound insulation board	reduced impact noise level of lsd stove

Notes

1 For PB-type slabs, airborne sound insulation parameters are set depending on the shape and size of the voids.

2 The reduced level of impact noise under the slab is taken from the results of experimental

research._

5.7 Floor structures used in floors, depending on the type of floor slab, are given in Table A.1 of Appendix A.

5.8 Plates should be marked with marks in accordance with GOST 23009. When establishing marks, the following provisions must be taken into account.

The slab brand consists of alphanumeric groups separated by hyphens.

The first group contains the designation of the plate type and overall dimensions - the structural length and width.

The structural length and width of the slab are indicated in decimeters (rounded to the nearest whole number), and the thickness is indicated in centimeters.

In the second group indicate:

The value of the design load in kilolascals.

Prestressing reinforcement class - for prestressed slabs.

For slabs made of lightweight concrete, the type of concrete is additionally indicated, denoted by the capital letter "L".

The third group, if necessary, includes additional characteristics that reflect the special conditions for the use of plates, their resistance to seismic and other influences, the designation of the design features of the plates, such as the type and location of reinforcing outlets, embedded products, etc. Special conditions for the use of plates are indicated in capital letters , design features of the plates - in lowercase letters or Arabic numerals.

An example of a symbol (brand) of a plate type 1 PK 5980 mm long. 1490 mm wide. under the design load of 4.5 kPa (450 kgf / m 2), made of heavy concrete with prestressing reinforcement class A800 (At-V):

1PK60.15-4.5A800

The same for a slab made of lightweight concrete:

1PC60.15-4.5A800L

The same for a plate supported on three sides:

1PK60.15-4.5A8003

The same for a slab supported on four sides:

1PK60.15-4.5A8004

Note - It is allowed to manufacture plates of other sizes and designate them with brands in accordance with the working drawings of standard structures until they are revised.

d SP 51.13330.2011 “SNiP 23*03-2003 Noise protection” is in force on the territory of the Russian Federation.

Applied floor structures

Table A.1

Annex B (informative)

Terms used in Annex A

B.1 Appendix A uses the following terms with their respective definitions:

B.1.1 single-layer floor: Paul. oosgoyatsion from the coating - linoleum on a heat and sound insulating basis, laid directly on the floor slabs.

B. 1.2 single-layer floor on a leveling screed: Pop. consisting of a coating - linoleum on a heat and sound insulating basis, laid on a leveling screed, laid directly on the floor slabs.

B.1.3 floating floor: Floor. consisting of a coating, a rigid base in the form of a monolithic or prefabricated screed and a continuous sound-proof layer of resiliently soft or loose materials laid on floor slabs.

B.1.4 hollow floor: Floor. consisting of a hard coating on the joists and soundproof gaskets laid on the floor slabs.

B.1.5 hollow-core layered floor: Floor. consisting of a hard coating and a thin soundproofing layer, laid directly on the floor slabs or on a leveling screed.

UDC 691.328.1.022-413:006.354 MKS 91.080.40

Keywords: lita, floor slab, solid slabs, multi-hollow slabs, coordination dimensions, structural length and width, standard size, types, parameters, brand, concrete, class, technical requirements, reinforcement, embedded parts.

EY editor. Shapygina Proofreader L.S. Lysenko Computer layout E.K. Kuzina

Signed for publication on February 8, 2016. Format 60x84"/*.

Uel. oven l. 1.40. Edition 37. Order. 62.

Prepared on the basis of the electronic version provided by the developer of the standard

FSUE "STANDARTINFORM"

123995 Moscow. Garnet lane.. 4.

Multi-hollow floor slabs GOST 9561-91
Name	Dimensions (LxWxH, mm)	volume, m3	Weight, t	Price for 1 unit with VAT, rub.
PK 24-12-8 AtV T	2380x1190x220	0,36	0,9	4306
PK 27-12-8 AtV T	2680x1190x220	0,40	1,01	4799
PK 30-12-8 AtV T	2980x1190x220	0,44	1,11	5429
PK 33-12-8 AtV T	3280x1190x220	0,49	1,22	5934
PK 36-12-8 AtV T	3580x1190x220	0,53	1,32	6439
PK 39-12-8 AtV T	3880x1190x220	0,57	1,42	6944
PK 42-12-8 AtV T	4180x1190x220	0,61	1,53	7383
PK 45-12-8 AtV T	4480x1190x220	0,65	1,62	7532
PK 48-12-8 AtV T	4780x1190x220	0,69	1,73	8004
PK 51-12-8 AtV T	5080x1190x220	0,73	1,83	8474
PK 54-12-8 AtV T	5380x1190x220	0,78	1,95	8910
PK 57-12-8 AtV T	5680x1190x220	0,82	2,05	9347
PK 60-12-8 AtV T	5980x1190x220	0,86	2,15	9886
PK 63-12-8 AtV T	6280x1190x220	0,90	2,25	10421
PK 72-12-8 AtV T	7180x1190x220	1,01	2,53	13405
PK 24-15-8 AtV T	2380x1490x220	0,50	1,25	4774
PK 27-15-8 AtV T	2680x1490x220	0,55	1,38	5397
PK 30-15-8 AtV T	2980x1490x220	0,60	1,52	5916
PK 33-15-8 AtV T	3280x1490x220	0,65	1,61	6642
PK 36-15-8 AtV T	3580x1490x220	0,70	1,75	7265
PK 39-15-8 AtV T	3880x1490x220	0,74	1,85	7784
PK 42-15-8 AtV T	4180x1490x220	0,80	2,02	8407
PK 45-15-8 AtV T	4480x1490x220	0,88	2,2	8834
PK 48-15-8 AtV T	4780x1490x220	0,94	2,35	9437
PK 51-15-8 AtV T	5080x1490x220	0,99	2,48	9861
PK 54-15-8 AtV T	5380x1490x220	1,05	2,63	10427
PK 57-15-8 AtV T	5680x1490x220	1,10	2,75	11010
PK 60-15-8 AtV T	5980x1490x220	1,14	2,85	11744
PK 63-15-8 AtV T	6280x1490x220	1,19	2,98	12343
PK 72-15-8 AtV T	7180x1490x220	1,34	3,35	16734

Multi-hollow 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. The top side of the floor slabs will be the base of the floor and the bottom side 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.

According to the external shape, the floor slabs are divided into flat and ribbed. Flat slabs, in turn, are multi-hollow and solid. Our company produces hollow core floor slabs PC. The diameter of the round voids is 159mm, the thickness of the plates is also standard and is 220mm. These slabs are intended for laying over load-bearing walls with support on two end sides.

Hollow-core slabs can withstand huge loads, but you should pay special attention to the storage of these products. To store the plates, it is necessary to prepare a flat surface in advance, pour and compact the sand cushion. Never lay tiles directly on the ground. Along the edges at the bottom of each slab, you need to put wooden bars. There should be two bars, at a distance of about 25-45 cm from each of the edges. It is categorically not recommended to lay bars under the middle part of the slab in order to avoid cracks and breaks. Stacking of hollow-core floor slabs is allowed in a stack with a height of no more than 2.5 meters.

Floor slabs lie evenly and without drops. To do this, it is necessary to achieve a position in one horizontal plane of all the upper rows of load-bearing walls. Before laying multi-hollow 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 within 15-25cm. When installing multi-hollow slabs, the holes in them are sealed. You can do this in advance when the slabs are stacked on the ground. Hollow core slabs are laid on a thick mortar. The solution layer should not exceed 2 cm.

The solution is applied over the brickwork. This is done in order to close the gaps, if there are differences, as well as for a better fit of the plates. The solution sets in 15-20 minutes, during this period of time you can move the plate to align its position relative to the walls. To avoid hardening of the mortar, it is applied immediately before lifting the floor slab. Raise hollow core slabs by mounting loops. After laying and leveling the first plate, proceed to the installation of the next one. The gaps at the joints are sealed with mounting foam and cement milk.

The production of floor slabs of various types and sizes is carried out in strict accordance with the requirements regulated by GOST 23009-78. The technology for the production of floor slabs in accordance with GOST of this edition has been used by enterprises since 1979.

The regulatory document provides for the main qualitative characteristics of the finished product, the possibility of its application in various areas of the construction industry. All products manufactured at factories have a marking that contains information about the characteristics of the floor slab, its overall parameters and purpose.

Classification of finished products is carried out taking into account the following criteria:

• construction type;
• the type of concrete used in the production;
• resistance to environmental factors;
• design features.

Possibilities of using building material

Concrete floor slabs are widely used in industrial and private construction in the construction of buildings for various purposes. Their use makes it possible to obtain a reliable and durable structure capable of withstanding high mechanical loads without losing its quality characteristics.

Reinforced concrete products are used in a number of works, namely:

• foundation laying;
• arrangement of tunnels;
• construction of flyovers;
• creation of strapping beams;
• construction of a base for cranes and other heavy construction equipment;
• erection of ceilings in residential and commercial buildings;
• creation of parapets;
• bottom device in the channels for communications;
• construction of support pads;
• construction of stairs, etc.

Installation of floor slabs is impossible without the use of special equipment, due to the large weight and large dimensions of the products.

To install floor slabs, it is necessary to rent a truck crane with a lifting capacity of up to 5 tons. With the help of special equipment, the installation of concrete products is carried out quickly and safely.

Rigging work

Loading, unloading and movement of blocks around the construction site is carried out due to the presence of embedded loops on the products, designed to hook the hooks of the cables. In the event that there are no fasteners on the products, it is necessary to think over in advance an alternative way to move them.

As a rule, the best solution is the use of special gripping devices (jigs). The ceilings, not equipped with hinges, have a trapezoidal section, and on the side surfaces of the product there are protrusions, for which the grips of the conductor are fixed.

Storage of concrete floors

In order to maintain quality characteristics and integrity, it is necessary to follow the rules for the maintenance of concrete products at the construction site. Products must be strictly in a horizontal position, it is strictly unacceptable to immerse reinforced concrete slabs in the ground, which leads to cracking of the ceiling. It is also impossible to lay the plates on top of each other, it is necessary to lay out the lining along the ends.

Installation procedure:

• Preparation of cement mortar.
• Setting the crane in working position, preparing for lifting.
• Applying the solution to the areas of support (layer - 2-3 cm).
• Transfer of the product to the installation site.
• Checking the reliability of the support of the product on the supporting structure.
• Lowering the cover.
• Checking horizontal seams.
• Filling voids with cement mortar.

When constructing structures that involve large weight loads, care must be taken to improve the bearing capacity. For this, the distance between the floor slabs must not only be filled with cement mortar, but also additionally reinforced. Along the outer perimeter of the structure, it is worth equipping a monolithic belt (width - at least 5 cm). The reinforcement cage must be made of two metal rods and laid vertically.

By the same principle, the joints between the plates located inside the ceiling are also strengthened. Thus, all structural elements of the floor are connected into a single monolithic block. The bearing capacity is significantly increased: for monolithic concrete structures - by 40%, and for cellular floors - by 100%.

Dimensions

In the market of concrete products in Russia, floor slabs are represented by a wide range. For each type of work (taking into account the expected load), manufacturers offer products of various overall dimensions. The table shows the most popular sizes of floor slabs of various brands.

Brand	Length, mm	Width, mm	Weight, t	Volume, m3
PC 17-10.08	1680	990	0,49	0,36
PC 20-10.08	1980	990	0,76	0,54
PC 30-10.08	2980	990	1,11	0,78
PC 40-10.08	3980	990	1,2	0,87
PC 51-10.08	5080	990	1,475	1,11
PC 60-10.08	5980	990	1,725	1,3
PC 70-10.08	6980	1190	2,06	1,52
PC 80-12.08	7980	1190	3,063	2,09
PC 90-12.08	8980	1190	3,2	2,38

The number "8" in the plate brand designation determines the optimal design load, which is 800 kgf / m 2. Which is a standard indicator for the construction of residential buildings.

Floor slabs - GOST

Floor slabs are used in the construction of multi-storey buildings for various purposes, the quality of products is the key to safe and long-term operation of the building. The slabs are produced in strict accordance with state standards, they can be composed of light, heavy or silicate concrete.

The production technology provides for the presence of voids in the material, which lighten the plate and provide it with increased heat and sound insulation qualities. The maximum allowable diameter of round voids is 15.9 mm. The minimum width of the plates is 1 m, and the maximum is 1.8 m. The length of the product is up to 9.2 m.

According to GOST floor slabs, the concrete used in the creation of slabs must meet class B22.5 in terms of quality parameters. The density of the cement powder should be 2000-2400 kg/m 3 .

The strength of the product is achieved through the use of heavy-duty steel reinforcement as a frame.

The state standard regulates the brand of concrete used, taking into account its frost resistance (F200.F). According to GOST 9561-91, hollow core slabs are made from concrete, the strength of which is 261.9 kg / cm 2.

Product range

Depending on the expected loads and other operating conditions, plates with the appropriate characteristics are cut. When choosing a material, it is necessary to pay attention to the type of reinforcement and the brand of concrete. The main types of concrete applicable in the creation of products:

• L- light;
• AND- heat-resistant;
• FROM– silicate;
• I- cellular;
• M- fine-grained.

Concrete products are also classified according to the degree of resistance to environmental factors. According to the quality of the surface of the product are:

• H– normal permeability;
• P– reduced permeability;
• O- special permeability.

Having studied the range of floor slabs, you can choose the product that is optimally suitable for each individual type of work.

The presence of the designation "C" in the marking indicates resistance to seismic vibrations, the degree of which does not exceed 7 points.

Depending on the purpose, the products can be monolithic or hollow. Monolithic products have increased strength and high weight, while products with voids are light in weight, which greatly facilitates the load on the supporting structure.

Hollow-core reinforced concrete floor slabs are one of the most popular types of reinforced concrete products, designed to separate building levels and lay load-bearing structures. Technical conditions and norms are controlled by GOST 9561-91, the characteristics allow them to be used in any field of construction: from private houses to industrial facilities. Mandatory nuances of application include the use of lifting equipment for laying and checking the bearing capacity. It is easy to choose the right series, the marking includes all the necessary information.

Externally, multi-hollow panels are a rectangular box with the correct geometry of the walls and ends, with longitudinal reinforcement, round or pear-shaped internal cavities spaced at regular intervals. For their production, heavy, light and dense silicate grades of concrete are used (for bearing systems, their strength class is not lower than B22.5). The voids are located parallel to the main direction along the length (for views based on 2 or 3 sides) or either side of the contour for slabs marked with RCC.

The presence of a frame is mandatory, to extend the service life and enhance reliability, all the metal placed inside is treated with anti-corrosion compounds at the manufacturing stage. In the panels, supported on 2 or 3 sides, a frame of prestressed reinforcement is laid. Depending on the purpose of the floor slabs, steel of one of the following grades is used: seven-wire strands with a section of 6P-7, a periodic profile of 5Vr-II, K-7 ropes, heat-hardened At-V rods and other materials that meet the standard (series 1 141.1 - the main a document regulating the process of release and quality control of products).

The main technical characteristics include:

1. Dimensions and weight of structures. The thickness is standard and unchanged (for most types - 220 mm), the length varies from 2.4 m to 12, the width is within 1-2.6 m. The exception is the types based on 4 sides (PKK marking), their dimensions vary from 3×4.2 to 3×7.2 m, respectively. Average weight 1 l.m. with a width of 1 m is 360 kg.

2. Bearing capacity. Depending on the brand of concrete and the intensity of reinforcement, slabs with voids withstand from 450 to 1200 kg/m2. The standard value for the most popular series with round holes is 800 kg/m2, if it is necessary to exceed it, the products are made to order.

3. The fire resistance limit of multi-hollow panels is 1 hour, if necessary, it is increased by strengthening the reinforcement cage.

Structures are valued for reliability, light weight, good bending tensile strength due to the presence of internal voids, the ability to hide communications, resistance to moisture, open fire, biological influences, heat and sound insulation properties, and durability. An important advantage is considered to be high geometric accuracy, which simplifies the process of installation and subsequent finishing.

Type of	Actual thickness, mm	Length (maximum, inclusive), m	Reduced slab thickness (ratio of concrete volume to area) mm	Hollow diameter, mm	Nominal distance between centers of voids, not less than mm
1PC, 1PCT, 1PCC	220	7.2 (up to 9 for slabs for industrial buildings supported exclusively on 2 sides)	120	159	185
2PCS, 2PCT, 2PCC		7,2	160	140
3PCS, 3PCT, 3PCC		6,3		127
4pcs	260	9,0		159 *
5pcs		12	170	180	235
6pcs			150	203	233
7pcs	160	7,2	90	114	139
PG	260	12	150
PB	220	Depends on molding parameters

* there are additional cutouts in the upper zone.

The main width standards are PK-10, PK-12 and PK-15. All types of holes are round, with the exception of PG - slabs with pear-shaped voids. For options with PKK marking, beveled ends are allowed.

All dimensions of reinforced concrete floors with holes inside are unified (including the length interval), deviations do not exceed 5 mm. The reduced thickness indicated in the table characterizes the efficiency of the product.

Hollow core marking

Standard decryption includes:

1. The figure characterizing the size of the diameter of the inner hole according to GOST 9561-91. It is omitted for 1PK, in most price lists there is a simple designation - PK.

2. Type. It is indicated by 2 or 3 letters, contains information about the shape of the voids, the method of manufacture and the number of supported sides. Of all varieties, PB is produced by continuous molding.

3. Dimensions of hollow-core floor slabs: first comes the length (of the side not supported by supporting structures), then the width, in dm, rounded up. The thickness is not indicated, this value depends on the type of product. The actual dimensions are always smaller: 20 mm in length, 10 in width.

4. The fourth mandatory item is a number reflecting the bearing capacity of the reinforced concrete product.

5. Type of reinforcement. May be omitted for non-tensioned frameworks.

6. Brand of solution: not indicated for heavy, used in the majority of products. The letter L means the use of lightweight concrete, C - dense silicate.

7. Other, additional characteristics or design features of products. These include resistance to seismic effects or aggressive gases, the presence of embedded elements.

Scope and features of application

The main purpose is the organization of a reliable prefabricated floor in objects with load-bearing walls (also used in construction). In private and low-rise construction, they are used for laying the main floors, separating floors and attic space, arranging shed roofs in outbuildings, playgrounds and as a fence. Their bearing capacity fully complies with construction requirements (the standard norm, when calculated taking into account the weight of people and furniture, is 150 kg / m2, the actual value exceeds it several times). Soundproofing characteristics allow you to provide reliable protection against noise even when installing single-layer floors.

Long slabs (up to 9 m for 1 PC, 12 for 4 PCs, 5 PCs, 6 PCs and PG) are intended for installation in public buildings, the rest are considered universal and are recommended for residential buildings, including individual ones. When choosing sizes, the need to comply with the standard for laying on supports is taken into account - from 7 to 15 cm, depending on the material of the walls (minimum - for dense brick, maximum - for aerated concrete). When converted into squares, the cost of 1 m2 for ceilings 1 m wide is more expensive than for products with 1.2 or 1.5 m, this is due to the ban on their transverse cutting. The use of reinforced concrete products of the PK series allows:

• Get a reliable design, designed for significant weight loads.
• Improve the insulating capacity of the building.
• Ensure a perfectly flat horizontal floor (with proper placement and check of the supports).
• Improve the water resistance, fire safety and acoustic protection of the building.

Cost of floor slabs

Series	Bearing capacity, kg/m2	Dimensions (length×width×thickness), mm	Weight, kg	Price for 1 piece, rubles
PC 16.10-8	800	1580×990×220	520	2 930
PC 20.12-8		1980×1190×220	750	4 340
PC 30.10-8		2980×990×220	880	6 000
PC 36.10-8		3580×990×220	1060	6 410
PC 45.15-8		4480×1490×220	2120	12 600
PC 60.18-8		5980×1780×220	3250	13 340
PC 90.15-8		8980×1490×220	4190	40 760
2PC 21.12-8	800	2080×1190×220	950	3 800
2PC 62.10-8		6180×990×220	2425	8 730