GOST floor slab series. Hollow-core floor slabs: GOST, dimensions, load

GOST 9561-91 contains the requirements mandatory for the manufacture of multi-hollow reinforced concrete slabs from light, heavy, dense silicate concrete intended for covering the load-bearing part of buildings and structures for various purposes. When using slabs for their intended purpose, be sure to follow the instructions in the working drawings and additional requirements that are specified when ordering structures. GOST 9561-91 is valid from 01/01/92.

GOST 9561-91

Group Zh33

STATE STANDARD OF THE USSR UNION

REINFORCED CONCRETE MULTI-HOLLOW FLOORS PLATES FOR BUILDINGS AND STRUCTURES

TECHNICAL CONDITIONS

Reinforced concrete multihollow panels

for floors in buildings. Specifications

Date of introduction 1992-01-01

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the State Committee for Architecture and Urban Planning under the USSR State Construction Committee (Goskomarchitektura) and the Central Research and Design Experimental Institute industrial buildings and structures (TsNIIpromzdany) of the USSR State Construction Committee

DEVELOPERS

L. S. Exler; A. A. Muzyko (topic leaders); I. I. Podguzova; A. A. Tuchnin, Ph.D. tech. sciences; E. N. Kodysh, Ph.D. tech. sciences; I. B. Baranova; V. G. Kramar, Ph.D. tech. sciences; G. I. Berdichevsky, Doctor of Engineering. sciences; V. L. Morozensky, Ph.D. tech. sciences; Yu. Ts. Khodosh; B.V. Karabanov, Ph.D. tech. sciences; V. V. Sedov; E. L. Shakhova; B. N. Petrov; Ya 3. Gilman; G. V. Turmanidze; N. A. Kapanadze; B.V. Kroshkov; V. I. Pimenova; V. I. Denshchikov

2. APPROVED AND ENTERED INTO EFFECT by Resolution of the USSR State Committee for Construction and Investment dated September 20, 1991 No. 5

3. INSTEAD OF GOST 9561-76 and GOST 26434-85 regarding types, main dimensions and parameters of hollow-core slabs

4. REFERENCE REGULATIVE AND TECHNICAL DOCUMENTS

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.

1. TECHNICAL REQUIREMENTS

1.1. Plates should be manufactured in accordance with the requirements of this standard and technological documentation approved by the manufacturer, according to working drawings standard designs(see Appendix 1) or designs of buildings (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.

1.2. Main parameters and dimensions

1.2.1. Plates are divided into types:

1PK - 220 mm thick with round voids with a diameter of 159 mm, designed for support 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.

1.2.2. The shape and coordination length and width of the slabs (except for PB type slabs) must correspond to those given in table. 1 and to hell. 1-3. 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. 1-3.

1.2.3. The structural length and width of the slabs (except for PB type slabs) should be taken equal to the corresponding coordination size (Table 1), reduced by the value a(1) (the gap between adjacent slabs) or a(2) (the distance between adjacent slabs if there is between them of a separating element, for example, an anti-seismic belt, ventilation ducts, crossbar ribs), or increased by the value a(3) (for example, for slabs supported on the entire thickness of the walls staircase buildings with transverse load-bearing walls). The values ​​of a(1), a(2) and a(3) are given in table. 2.

1.2.4. 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 1

Note. The length of the slabs is taken to be:

size of the side of the slab not supported by bearing structures buildings (structures) - 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 types 1PK, 2PK, 3PK, 5PK, 6PK, 7PK

Plates of types 1PKT, 2PKT, 3PKT

Plates of types 1PKK, 2PKK, 3PKK

Plate type 4pcs

Plate type PG

Notes to hell. 1-3

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. 1-3 as an example. It is permissible 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 1b) and along the contour of slabs of type 4PK (Drawing 2) 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 releases of reinforcement for connections between slabs, walls, and anti-seismic belts.

table 2

1.2.5. Voids in slabs intended to be supported on two or three sides should be located parallel to the direction along 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.

1.2.6. The slabs should be made with recesses or grooves on the side faces to form, after embedding, intermittent or continuous keys that provide working together floor slabs for shear in 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.

1.2.7. Slabs intended to be supported on two or three sides should be made prestressed. Slabs with a thickness of 220 mm, a length of less than 4780 mm, with voids with diameters of 159 and 140 mm and slabs with a thickness of 260 mm, with a length of less than 5680 mm, as well as slabs with a thickness of 220 mm, of any length, with voids with a diameter of 127 mm may be manufactured with non-prestressing reinforcement.

1.2.8. 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. 1-3). When the design load on the ends of the slabs in the wall support zone does not exceed 1.67 MPa (17 kgf/sq.cm), it is allowed, by agreement between the manufacturer and the consumer, to supply slabs with unreinforced ends.

Reinforcement methods and minimum dimensions of embedments are established in working drawings or indicated when ordering slabs.

1.2.9. In cases provided for by the working drawings of a particular building (structure), slabs may have embedded products, reinforcement outlets, local cutouts, holes and other additional structural details.

1.2.10. To lift and install slabs, mounting loops or special gripping devices are used, the design of which is established by the manufacturer in agreement with the consumer and the design organization - the author of the building (structure) project. The location and dimensions of the holes in the slabs intended for loopless installation are taken according to the drawings included in the design documentation of the gripping device for these slabs.

1.2.11. The consumption of concrete and steel on the slabs must correspond to those indicated in the working drawings of these slabs, taking into account possible clarifications made by the design organization in the prescribed manner.

1.2.12. The slabs are used taking into account their fire resistance limit specified in the working drawings of the slabs.

1.2.13. 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 type of slab, 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:

the calculated load on the slab in kilopascals (kilogram-force per square meter) or the serial number of the slab in terms of 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, indicate additional characteristics, reflecting 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).

Example symbol(grade) slab type 1PK 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:

1PK63.15-6AtVL

The same, made of heavy concrete and intended for use in buildings with a calculated seismicity of 7 points:

1PK63.15-6AtV-S7

Note. It is allowed to accept the designation of slab brands in accordance with the working drawings of the slabs until they are revised.

1.3 Characteristics

1.3.1. The slabs must meet the requirements established during the design for strength, rigidity, crack resistance, and when tested by loading in the cases provided for in the working drawings, withstand control loads.

1.3.2. The slabs must meet the requirements of GOST 13015.0:

according to the actual strength of concrete (at design age, transfer and tempering);

on the frost resistance of concrete, and for slabs operated under conditions of exposure to an aggressive gaseous environment - also on the water resistance of concrete;

according to the average density of lightweight concrete;

to steel grades for reinforcing and embedded products, including mounting loops;

by deviations in the thickness of the protective layer of concrete to the reinforcement;

for corrosion protection.

Slabs used as the load-bearing part of loggias must also meet the additional requirements of GOST 25697.

1.3.3. 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/cub.m in accordance with GOST 25820 or dense silicate concrete with an average density of at least 1800 kg/cub.m in accordance with GOST 25214 strength classes or grades for compression specified in the working drawings of these slabs.

1.3.4. Compression forces (releasing the tension of the reinforcement) are transferred to the concrete after it reaches the required transfer strength.

The normalized transfer strength of concrete of prestressed slabs, depending on the class or grade of concrete in terms of compressive strength, the type and class of prestressing reinforcing steel, must correspond to that indicated in the working drawings of these slabs.

1.3.5. The normalized tempering strength of concrete for prestressed slabs made of heavy or light concrete for the warm season should be equal to the normalized transfer strength of concrete, and for slabs with non-prestressed reinforcement - 70% of the compressive strength of concrete corresponding to its class or grade. When delivering these slabs in the cold season or to ensure their safety during transportation by rail in the warm season (by agreement between the manufacturer and consumer of the slabs), the normalized tempering strength of concrete can be increased to 85% of the compressive strength of concrete corresponding to its class or grade .

The normalized tempering strength of concrete for slabs made of dense silicate concrete should be equal to 100% of the compressive strength of concrete corresponding to its class or grade.

1.3.6. To reinforce slabs, the following types and classes of reinforcing steel should be used:

as prestressed reinforcement - thermomechanically strengthened rod of classes At-IV, At-V and At-VI according to GOST 10884 (regardless of weldability and increased resistance to corrosion cracking of the reinforcement), hot-rolled rod of classes A-IV, A-V and A-VI according to GOST 5781, reinforcing ropes of class K-7 according to GOST 13840, high-strength periodic wire of class VR-II according to GOST 7348, wire of class VR-600 according to TU 14-4-1322 and rod reinforcement class A-I IIv, made of reinforcing steel of class A-III according to GOST 5781, strengthened by drawing with control of the stress value and ultimate elongation;

as non-stressed reinforcement - hot-rolled rod of periodic profile of classes A-II, A-III and smooth class A-I according to GOST 5781, periodic wire of class BP-I according to GOST 6727 and class BP-600 according to TU 14-4-1322.

In slabs produced by methods of continuous formless molding on long stands, continuous reinforcement, as well as using multi-temperature electrothermal tension, high-strength wire reinforcement is used in accordance with GOST 7348 and ropes in accordance with GOST 13840.

1.3.7. The shape and dimensions of reinforcement and embedded products and their position in the slabs must correspond to those indicated in the working drawings of these slabs.

1.3.8. Welded reinforcement and embedded products must comply with the requirements of GOST 10922.

1.3.9. The stress values ​​in the prestressing reinforcement, monitored after tensioning it on the stops, must correspond to those indicated in the working drawings of the slabs.

The values ​​of actual stress deviations in prestressed reinforcement should not exceed the limits specified in the working drawings of the slabs.

1.3.10. Values ​​of actual deviations geometric parameters slabs should not exceed the limits specified in the table. 3.

Table 3

* The deviation from the size that determines the position of the embedded product from the upper plane of the slabs intended for direct gluing of linoleum should only be inside the slab.

1.3.11. Requirements for the quality of concrete surfaces and appearance slabs (including requirements for the permissible opening width of technological cracks) - according to GOST 13015.0 and this standard.

1.3.12. The quality of concrete slab surfaces must meet the requirements established for the categories:

A3 - lower (ceiling);

A7 - top and side.

By agreement between the manufacturer and the consumer, the following categories of surfaces can be installed instead of the indicated ones:

A2 - lower (ceiling), prepared for painting;

A4 - the same, prepared for wallpapering or decorative finishing paste-like compositions, and the top, prepared for covering with linoleum;

A6 - lower (ceiling), for which there are no requirements for the quality of finishing.

1.3.13. In the concrete of slabs supplied to the consumer, cracks are not allowed, with the exception of shrinkage and other surface technological cracks with a width of no more than 0.3 mm on the top surface of the slabs and no more than 0.2 mm on the side and bottom surfaces of the slabs.

1.3.14. Exposure of reinforcement is not allowed, with the exception of reinforcement outlets or ends of prestressing reinforcement, which should not protrude beyond the end surfaces of the slabs by more than 10 mm and should be protected with a layer of cement-sand mortar or bitumen varnish.

1.4. Marking

Marking of slabs is in accordance with GOST 13015.2. Markings and signs should be applied to the side faces or top surface of the slab.

On the upper surface of a slab supported on three sides, signs “Location of support” should be placed in accordance with GOST 13015.2, located in the middle at each side of the slab support.

2. ACCEPTANCE

2.1. Acceptance of slabs is in accordance with GOST 13015.1 and this standard. In this case, the slabs are accepted based on the results:

periodic testing - in terms of strength, rigidity and crack resistance of slabs, frost resistance of concrete, porosity (volume of intergranular voids) of a compacted mixture of lightweight concrete, as well as water resistance of concrete slabs intended for use in exposure conditions aggressive environment;

acceptance tests - in terms of concrete strength (class or grade of concrete in terms of compressive strength, transfer and tempering strengths), average density of light or dense silicate concrete, compliance of reinforcement and embedded products with working drawings, strength welded joints, the accuracy of geometric parameters, the thickness of the protective layer of concrete before the reinforcement, the opening width of technological cracks and the category of the concrete surface.

2.2. Periodic loading tests of slabs to control their strength, rigidity and crack resistance are carried out before the start of their mass production and in the future - when design changes are made to them and when manufacturing technology changes, as well as during the mass production of slabs at least once a year. Load testing of slabs in the event of structural changes being made to them and when manufacturing technology is changed, depending on the essence of these changes, may not be carried out in agreement with the design organization that developed the working drawings of the slabs.

Testing of slabs with a length of 5980 mm or less during their serial production may not be carried out if non-destructive testing is carried out in accordance with the requirements of GOST 13015.1.

2.3. Slabs in terms of the accuracy of geometric parameters, the thickness of the protective layer of concrete to the reinforcement, the width of the opening of technological cracks and the category of the concrete surface should be accepted based on the results of random inspection.

2.4. The porosity (volume of intergranular voids) of a compacted lightweight concrete mixture should be determined at least once a month.

2.5. The document on the quality of slabs intended for use in conditions of exposure to aggressive environments must additionally indicate the grade of concrete for water resistance (if this indicator is specified in the order for the production of slabs).

3. CONTROL METHODS

3.1. Load tests of slabs to control their strength, rigidity and crack resistance should be carried out in accordance with the requirements of GOST 8829 and working drawings of these slabs.

3.2. The strength of concrete slabs should be determined according to GOST 10180 on a series of samples made from concrete mixture working personnel and stored under the conditions established by GOST 18105.

When determining the strength of concrete using methods non-destructive testing the actual transfer and tempering compressive strength of concrete is determined by the ultrasonic method according to GOST 17624 or by instruments mechanical action according to GOST 22690. It is allowed to use other non-destructive testing methods provided for by the standards for concrete testing methods.

3.3. The frost resistance of concrete slabs should be determined according to GOST 10060 or by the ultrasonic method according to GOST 26134 on a series of samples made from a concrete mixture of the working composition.

3.4. The water resistance of concrete slabs intended for operation in conditions of exposure to aggressive environments should be determined according to GOST 12730.0 and GOST 12730.5.

3.5. The average density of light and dense silicate concrete should be determined according to GOST 12730.0 and GOST 12730.1 or by the radioisotope method according to GOST 17623.

3.6. The porosity indicators of a compacted mixture of lightweight concrete should be determined according to GOST 10181.0 and GOST 10181.3.

3.7. Inspection of welded reinforcement and embedded products - in accordance with GOST 10922 and GOST 23858.

3.8. The tension force of the reinforcement, controlled at the end of the tension, is measured according to GOST 22362.

3.9. The dimensions of the slabs, deviations from the straightness and flatness of the surfaces of the slabs, the width of the opening of technological cracks, the sizes of cavities, sagging and edges of concrete slabs should be determined by methods established by GOST 26433.0 and GOST 26433.1.

3.10. The dimensions and position of reinforcement and embedded products, as well as the thickness of the protective layer of concrete up to the reinforcement, should be determined according to GOST 17625 and GOST 22904. In the absence of the necessary equipment, cutting furrows and exposing the slab reinforcement with subsequent sealing of the furrows is allowed. Furrows should be punched at a distance from the ends not exceeding 0.25 times the length of the slab.

4 TRANSPORTATION AND STORAGE

4.1. Transportation and storage of slabs - in accordance with GOST 13015.4 and this standard.

4.2. The slabs should be transported and stored in stacks laid in a horizontal position.

It is allowed to transport slabs in an inclined or vertical position on specialized vehicles.

4.3. The height of the stack of slabs should not be more than 2.5 m.

4.4. Pads for the bottom row of slabs and spacers between them in a stack should be located near the mounting loops.

ANNEX 1

LIST OF SIZES AND SERIES

WORKING DRAWINGS OF PLATES FOR MASSIVE APPLICATION

Table 4

APPENDIX 2

AREA OF APPLICATION OF VARIOUS TYPES OF PLATES

Table 5

APPENDIX 3

Information

TERMS USED IN APPENDIX 2 AND THEIR EXPLANATIONS

Table 6

The text of the document is verified according to:

official publication

Gosstroy USSR - M: Standards Publishing House, 1992

Reinforced concrete slabs are used in building construction to redistribute loads from the weight of furniture, equipment, snow and other heavy elements directly onto the load-bearing walls or columns of the building. They divide the space of the building transversely vertically or cover the top floor for the manufacture of roofing.

Floor elements are used in the construction of large shopping and industrial complexes, entertainment centers, cultural and public spaces, and multi-story residential buildings. In private construction, prefabricated reinforced concrete slabs They are successfully used for covering and covering the upper floors, creating a reliable and durable frame of the house.

According to the form of internal content, reinforced concrete products are divided into types: hollow and ribbed.

Depending on the thickness, cavity dimensions and method of support on load-bearing elements, hollow core slabs are divided into categories in accordance with GOST.

With different support method

a) 1pc thickness is 220mm, voids are formed with a diameter of 159 mm, support occurs on two sides, length from one and a half to six and a half meters, width from 1 to 3.5 m, 1 pct - support on three sides, 1PKK - trough four-sided support;

b) 2 pcs - slab height 220 mm, voids with a diameter of 140 mm, 2 pkt - support on three sides, length ranges from three to six meters, 2 pkt - four-sided support, length 2.5–6.7 m;

c) 3PK - 220 mm, voids are made diameter 128 mm, designations of the supporting sides are similar to the previous ones;

With support on only two sides

A) 4pcs slabs They are produced with a thickness of 260 mm, voids of 158 mm, in the upper belt there are cutouts along the entire contour. Cover spans up to 6 m, width up to 1.5 m;

b) 5 pcs- product body height 260 mm, hollow hole diameter 181 mm, length for spans up to 12 m, width 1.1 m, 1.25 m, 1.48 m;

V) 6 pcs plates manufactured with a height of 300 mm, voids round shape 204 mm are produced in a maximum length for large spans of 12 m;

d) 7 pc-thickness products are provided 160 mm, round voids with a diameter of 115 mm, cover average spans up to 6.5 m, width 1.1 m, 1.25 m, 1.49 m, 1.81 m;

d) PG-voids pear-shaped, slab thickness 260 mm, purlin length 12 m, different widths available, up to 1.5 m;

e) PB-series, produced using continuous forming technology on stands;

Ribbed floor slabs

In order to save light or heavy concrete mixtures, concrete was removed from the bottom layer of the slab, which does not work well under tensile loads, and has excellent resistance to compression. Under the influence of forces, compression forces arise in the upper layer of the slabs, and tensile forces in the lower layer.

Instead of concrete, slabs are provided along the entire length inserts from metal fittings , withstanding tensile forces. To accommodate them, stiffeners are made of concrete. In ribbed slabs, to cover spans of more than 12 m, transverse convex grooves are additionally made in accordance with GOST.

Ribbed reinforced concrete products are divided into series according to GOST

• 1P are called slabs that have two strips of support on separate shelves of the crossbar; they are available in varieties from 1P1 to 1P8;
• The support on the crossbar is designated 2P and is available in a single version;
• In slabs of the 1P1–1P6 series, GOST provides for the installation of embedded parts at the junction of the ends, if required by the drawing documents;
• Prestressing of reinforcement is carried out before concreting in product forms 1P1–1P6 and 2P1;
• The reinforcement is not stressed electromechanically during the manufacture of types 1P7 and 1P8.

An example of decoding the designation of slabs according to GOST: 1P4– 2, At - VI P-1

• First three letters they talk about the standard size of the slab (1P4);
• Number 2 indicates the load-bearing capacity class of the product;
• At - VI is a typical designation of reinforcement from the assortment directory;
• The letters P and T determine the type based on the density of the concrete used in its manufacture. P-light option, T-heavy concrete mixture.

The last digit separated by a dash shows the features of the view in the manufacture of reinforced concrete products. 1- the presence of various additional metal elements; 2-side ribs contain holes of 208 mm; number 3 indicates holes of different diameters on both sides;

Scope of application of reinforced concrete slabs according to GOST

GOST requirements for technical indicators

Finished slabs are subject to acceptance provided:

The overall dimensions of reinforced concrete products must comply with standard approved technical documentation.

At the exit of the finished product, strength tests, crack resistance and rigidity. The indicators obtained during the experiments must not be lower than the normative ones provided for in the documents.

Parameters of compressive and bending strength, frost resistance, deviations in size from the norm are set out in the publication of GOST 13015.0–83;

The production and formation of the slab is carried out in strictly approved and developed forms. All metal embedded elements are manufactured from a certain class of steel, approved diameter. It is mandatory to treat metal surfaces with anti-corrosion compounds.

Concrete must meet the requirements according to GOST:

When manufacturing reinforced concrete products from lightweight concrete, its density per 1 m3 should be in the range of 1900–2100 kg. Heavy concrete density can correspond to 2250–2550 kg per 1 m3.

If the specification for the slab type specifies pre-tensioning of reinforcement, then it is released only after the concrete mixture has reached its design strength. Typically, this indicator is provided in whole days of hardening and is indicated in the drawing for the production of the slab or in the technical documentation for the building under construction.

Lightweight types of concrete mix necessarily correspond to porosity indicators, taking into account tolerances and deviations.

The quality of all local materials and binding components involved in the production of concrete mixture must be within standard limits in the relevant GOSTs.

When operating in an aggressive acidic or gaseous environment, the regulations for the production of products are determined in the documents for the building.

Conditions for conformity of reinforcing wire

GOST defines the name and classes of reinforcing steels permitted when using slabs in different operating environments. A separate list defines the types of steels that are not allowed for the production of products due to low technical indicators.

Metal mounting loops must withstand the weight of the hinge when moving, the embedded parts of the product, welded during the installation process, can take various loads up to working in extreme conditions. All elements laid in the concrete mixture must be calculated according to all indicators. Their shape, dimensions and diameter are clearly defined by GOSTs and are not subject to change.

Preliminary reinforcing steel stress, by tension, electromechanically or mechanically.

The voltage generated in the metal wire is measured with special devices, and it should not be lower than the nominal voltage by 10%.

Acceptance of finished products

The frost resistance of floor elements is checked by the labor control department on prototypes by large quantity freezing and thawing cycles. The results are recorded in special passports.

Porosity and water permeability thresholds are checked for each type of concrete mixture separately and documented in the necessary documents.

To be approved for use, the product undergoes a series of tests for strength, density, and hardness.

All metal elements are subject to visual and instrumental control for compliance with drawings, technical documentation and GOST. If necessary, a report is drawn up for hidden work on laying reinforcement.

Concrete porosity indicators must be exactly as in the project or in the order, comply with GOST.

The compliance of the slabs with the dimensions indicated in the drawings is carried out systematically and selectively. The surface is inspected in the same way for the appearance of microcracks.

Check the layer upon release protective concrete for metal on the edges of the slab using X-ray devices.

Rules for transporting floor slabs

All inscriptions indicating the brand of the slab, applied with contrasting color paint on the side or end surface so that they are visible when stacked on top of each other.

It is permitted to transport and deliver slabs to the construction site only if you have the appropriate passport indicating all technical specifications products.

For storage in hangars or outdoor construction sites slabs are stacked, not exceeding 2.5 m in height. A wooden spacer in the form of a beam measuring about 50x50 mm is made under each slab; wooden elements placed in corners or under protruding elements (for example, ribbed products).

The use of high-quality floor slabs is important when constructing a building. If damaged, cracked or bent products are used in violation of overall dimensions, the strength of the building frame will decrease, which in difficult conditions can lead to collapse.

Can only be used for styling factory-made products with documents. You can also install used slabs, but first obtain the results of testing and inspection by construction experts in accordance with GOST.

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 total weight Houses. 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.

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 a significantly greater 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.

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 hollow-core panel slabs, the length of which is 6000 mm and the width of 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 importance has, of course, the weight of the floor panel. Concrete floor slabs must be lifted by a crane with a minimum lifting capacity of 4-5 tons.

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.

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:

1. 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;
2. The lower part, with the presence of the ceiling, its decoration, 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 you take large rooms, with columns and halls, huge crystal chandeliers can hang there, which will give a greater load than any other device or type of decoration. This must also be taken into account;
3. 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.

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 a much greater negative impact on the hollow-core slab. 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. And here suspended ceiling with a frame over the entire surface of the slab - this is already a distributed load.

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.

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. The last digit (in this case 10) is 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

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 flooring
• or panels;

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 the 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.

Now you need to subtract the weight of the furniture from this indicator, finishing materials, the weight of people who will constantly be indoors or in the 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.

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 of different types of hollow core slabs.

Looking at stacks of reinforced concrete slabs, the average citizen has no idea how much important information they can convey to a specialist builder. This is not surprising, because in Everyday life we rarely come across such designs.

If we're talking about about the new building, then to the customer installation work It will be useful to know what types and sizes of floor slabs exist, as well as what their maximum load-bearing capacity is according to GOST.

At first glance, the differences between hollow core slabs are only in their length, thickness and width. However, the technical characteristics of these structures are much more extensive, so we will look at them in more detail.

State standard - a set of laws of strength

All basic requirements for hollow core slabs, including their purpose and strength characteristics, describes GOST 9561-91.

First of all, it indicates the gradation of the slabs depending on their thickness, the diameter of the holes and the number of sides with which they rest on the walls.

In addition to different thicknesses and geometric dimensions Hollow-core floor slabs are classified according to the method of reinforcement. GOST indicates that panels that rest on walls on 2 or 3 sides must be made using prestressed reinforcement.

The practical conclusion that follows from this for the developer is that you cannot punch holes for engineering Communication, violating the integrity of the working fittings. Otherwise the plate may lose bearing capacity(crack under load or collapse).

Clause 1.2.7 of GOST 9561-91 makes important exceptions, allowing for the manufacture of certain types of slabs not to install prestressed reinforcement in them.

They refer to the following panels:

• Thickness 220 mm with length 4780 mm (voids with a diameter of 140 and 159 mm);
• Thickness 260 mm, length less than 5680 mm;
• 220 mm thick, any length (voids with a diameter of 127 mm).

If such reinforced concrete floor slabs were brought to your site, and their passport indicates non-tensioned reinforcement, do not rush to send the car back to the factory. These structures comply with building codes.

Features of manufacturing technology

Floor slabs are made different ways, which is reflected in the quality of their front surface. PC and PG grade slabs are cast in formwork, and PB panels are made continuously on a conveyor line. Latest technology formwork manufacturing is more perfect, therefore the surface of PB slabs is more even and smooth than that of panels of the PC and PG brands.

In addition, conveyor production makes it possible to produce PB slabs of any length (from 1.8 to 9 meters). This is very convenient for the customer when it comes to so-called “additional” slabs.

The fact is that when laying out slabs on a building plan, several areas are always formed where standard panels do not fit. Builders get out of the situation by filling such “blank spots” with monolithic concrete directly on site. The quality is so homemade design noticeably inferior to that achieved in factory conditions (vibration compaction and steaming of concrete).

The advantage of PC and PG panels over PB panels is that you can punch holes in them for communications without fear of structural destruction. The reason is that their void diameter is at least 114 mm, which allows free passage sewer riser(diameter 80 or 100 mm).

PB slabs have narrower holes (60 mm). Therefore, to pass the riser, you have to cut the rib, weakening the structure. Experts say that such a procedure is unacceptable only for high-rise construction. When constructing low-rise housing, punching holes in PB slabs is allowed.

Advantages of hollow reinforced concrete slabs

There are a lot of them and they are all quite significant:

• Reducing the weight of building structures;
• The voids in the slabs dampen vibrations, so this type of flooring has good sound insulation;
• Possibility of laying communications inside voids;
• Fire resistance and moisture resistance;
• High speed of installation work;
• Durability of the structure.

Dimensions of hollow core slabs

Here everything is unified to the maximum so that it is possible to make a design of any installation size. The gradation of the width and length of the slabs occurs in increments from 100 to 500 mm.

Marking – passport of the floor slab

The developer does not need to know the intricacies of the technology used to produce a hollow-core floor slab. It is enough to learn how to correctly decipher the markings.

It is carried out in accordance with GOST 23009. The stove brand includes three alphanumeric groups separated by hyphens.

The first group contains data on the type of panel, its length and width in decimeters (rounded to the nearest whole number).

The second group indicates:

• Load-bearing capacity of the slab or design load (kilopascals or kilogram-force per 1 m2);
• For prestressed slabs, the class of reinforcing steel is indicated;
• Type of concrete (L - light, S - silicate, heavy concrete is not indicated in the markings).

The third group of markings contains additional characteristics that reflect the special conditions of use of structures (resistance to aggressive gases, seismic influences, etc.). In addition, the design features of the slabs (the presence of additional embedded parts) are sometimes indicated here.

As an example to explain the principle of marking hollow-core panels, consider the following design:

Hollow-core panel type 1PK, length 6280 mm, width 1490 mm, designed for a load of 6 kPa (600 kg/m2) and made of lightweight concrete using prestressed reinforcement class At-V).

Its marking will look like this: 1PK63.15-6AtVL. Here we see only two groups of characters.

If the slab is made of heavy concrete and is intended for use in a seismic zone (seismicity up to 7 points), then a third group of symbols appears in its designation: 1PK 63.15-6AtV-C7.

The considered technical characteristics of floor slabs determine their scope of application.

All types of hollow-core panels are calculated based on the standard load on the floor - 150 kg/m2 (weight of people, equipment and furniture).

Load bearing capacity standard plate is in the range from 600 to 1000 kg/m2. Comparing the standard of 150 kg/m2 with the actual strength of the panels, it is easy to see that their safety margin is very high. Therefore, they can be installed in all types of residential, industrial and public buildings.

This table contains the given thickness of the slab - a term that is not understood by beginners. This is not the geometric thickness of the panel, but a special parameter created to assess the efficiency of the slabs. It is obtained by dividing the volume of concrete placed in the slab by its surface area.

Approximate prices

During construction, dozens of standard sizes of hollow core slabs are used, therefore detailed description Their prices would have to be devoted to a separate article. We will indicate the price parameters of the most popular panels (pickup):

• PC 30.12-8 – from 4,800 rub./unit;
• PC 30.15-8 – from RUB 5,500/unit;
• PC 40.15-8 – from RUB 7,600/unit;
• PC 48.12-8 – from 7,000 rub./unit;
• PC 51.15-8 – from RUB 9,500/unit;
• PC 54.15-8 – from RUB 9,900/unit;
• PC 60.12-8 – from RUB 8,200/unit;
• PC 60.15-8 – from 10,600 rub./unit;

Installation of hollow core slabs

The main condition for high-quality installation of panels is strict adherence to the design parameters for support on the walls. Insufficient support area leads to destruction of the wall material, and excessive support leads to increased heat loss through cold concrete.

Installation of floor slabs must be carried out taking into account the minimum permissible depth of support:

• on brick - 90 mm;
• for foam concrete and aerated concrete blocks - 150 mm;
• on steel structures— 70 mm;
• for reinforced concrete - 75 mm;

The maximum depth of embedding slabs into walls should not be more than 160 mm (brick and light blocks) and 120 mm (concrete and reinforced concrete).

Before installation, each slab must be filled with voids (with lightweight concrete to a depth of at least 12 cm). Laying the panel “dry” is prohibited. To ensure uniform load transfer on the walls, before laying, spread a mortar “bed” no more than 2 cm thick.

In addition to observing the standard support depths, when installing floor slabs on fragile blocks of gas or foam concrete, a monolithic concrete slab should be laid underneath them. reinforced belt. It eliminates the squeezing of blocks, but requires good external insulation to eliminate cold bridges.

During the installation process, the deviation of the difference in elevations of the front surfaces of adjacent panels should be constantly monitored. This needs to be done at the seams. Don’t listen to builders who install panels in “steps” and tell you that it is impossible to lay them straighter.

Building codes establish the following tolerances depending on the length of the slabs:

• up to 4 meters – no more than 8 mm;
• from 4 to 8 meters – no more than 10 mm;
• from 8 to 16 m – no more than 12 mm.

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

Explanations for the table.

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.

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

From 3600 to 6300 inclusive. at intervals of 3000 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.

1 – 1 1 – 1

Plates of types 1PKT, 2PKT, 3PKT, 5PK, 6PK, 7PKT slabs of types 1PKT, 2PKT, 3PKT
P

2
–2

casts of types 1PKK, 2PKK, 3PKK

1
–1 2–2

Crap. 10. 4pc type plate

1 –1 2–2

Crap. 11. Plate type PG Notes

1. to hell 9-11

2. Slabs of types 1PKT, 2PKT, 3PKT, 1PKK, 2PKK and 3PKK can have technological bevels along all side faces.

3. Methods for strengthening the ends of the slabs are shown in Fig.

4. 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.

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.

Voids in slabs intended to be supported on two or three sides should be located parallel to the direction along 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.

Reinforcement methods and minimum dimensions of embedments 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 type of slab, 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:

the calculated load on the slab in kilopascals (kilogram-force per square meter) or the serial number of the slab in terms of bearing capacity;

steel class of prestressed reinforcement (for prestressed slabs); ( type of concrete - L

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 of the design features of the 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.