Overlapping panels and decking. Wooden or reinforced concrete floors? Monolithic reinforced concrete floor technology

Reinforced concrete floors are strong, durable and non-combustible. Before the development and implementation in the practice of building prefabricated structures reinforced concrete floors performed monolithic.

Monolithicceilings are reinforced and concreted on the spot, in the formwork. IN modern construction monolithic ceilings are used when they are the main element providing the overall spatial rigidity of the building, in buildings complex shape (in plan), as well as with significant dynamic loads on floors.

Depending on the load, spans up to 3 m can be covered with a smooth slab 60-100 mm thick. For spans more than 3, ribbed floors are arranged (Fig. 6.6, a ), consisting of a slab, main beams (purlins) and secondary beams (ribs). Distance between main beams - from 4 to 6 m , and between the ribs with a slab thickness of 70-100 m m- from 1.5 to 3 m . Multi-span floor beams are continuous structures. The main beams are supported by columns, and the ribs are supported by girders.

To obtain a smooth ceiling with a ribbed ceiling, plaster is made according to steel mesh, suspended from the ribs from below, or fix dry plaster sheets on special suspensions. In the upper floor, a smooth ceiling can be obtained by installing a monolithic reinforced concrete floor with the ribs up.

Ribbed slabs have a rectangular grid of columns. With a square grid of columns (when the distances between the columns in both directions of the span to be covered are the same), the floors can be of the caisson type (Figure 6.6, b).

Figure: 6.6. Monolithic reinforced concrete floors:

a - ribbed; b - caisson; в - bezelless; 1 - main beams (girders); 2 - secondary beams (ribs); 3 - plate; 4 - columns; 5 - clean floor; 6 - small capital.

If it is necessary to obtain a smooth ceiling, the ceilings can be of a non-girder structure (Fig. 6.6, c) with a slab thickness equal to 1/35 of the span, resting on columns that have widening (capitals) in the upper part, which provide the slab strength for punching and better coupling slabs with columns. Column grid allowed 5x5 or 6X6 m .

Prefabricated reinforced concrete floors are divided into floors:

On reinforced concrete beams;

From reinforced concrete slabs;

Decking;

Large panels.

Overlappings on reinforced concrete T-section beams (Fig. 6.7-6.8) are simple in design, have a low weight of mounting elements, but are laborious due to cement mortar filling a large number of seams between the elements of inter-beam filling (roll-up). The spacing of the beams is prescribed depending on the load: 600, 800, 1000 mm. As an inter-beam run-up, empty-body lightweight concrete inserts-shea stones, reinforced slag concrete or gypsum are used concrete plates.

The floors are arranged on logs or on a leveled base. The ceilings are covered with a layer of plaster, no more than 10 mm . The connection of the floor to the walls is carried out by anchoring the floor beams (Fig. 6.8, c).

The beams of the attic floor are insulated (Fig. 6.7.6).

Figure: 6.7. Interfloor ceilings on precast concrete beams:

a - with a roll of plates; b - filled with inserts; 1- gypsum concrete

plates; 2 - lightweight concrete liners; 3 - slag; 4 - soundproof

gasket; 5 - lag; 6 - plank floor; 7 - hardboard; 8 - roofing; 9 - light

concrete; 10 - clean floor; 11 - grout.

Overlapping from large-sized reinforced concrete elements are made in the form of slabs, flooring and prefabricated panels in accordance with the nomenclature of prefabricated reinforced concrete products for civil buildings.

Figure: 6.8. Overlapping on reinforced concrete beams (anchoring):

5 - solution; 12 - slag concrete; 13 - mounting loop; 14 - anchor.

Depending on the structural scheme of the building, there are floors made of long reinforced concrete slabs (slabs), laid on longitudinal bearing walls or on longitudinal girders; from slabs, panels or decking laid on transverse load-bearing walls or on transverse purlins; from panels resting on four sides or but four corners on the columns of the frame (Fig. 6.9). For the latter scheme, ribbed and hipped-roof panels are used - reinforced concrete slabs with dimensions per room, weighing up to 5 tons . The main types of long slabs, decks and the construction of floors from them are shown in Figure 6.10.

Hollow slabs with round, oval and vertical voids are widely used, forming smooth ceilings of premises and an even surface under the base of floors. Hollow core slab widths from 1200 to 3600 mm , length is from 2.4 m to 12 mi height is 220 mm . To avoid the destruction of slabs under load from the weight of the walls in the places where they are embedded in the walls top shelf (slab) has cutouts on the supports, which are laid with solid concrete inserts. The slab must be embedded in the wall for at least 10 cm and connected to other slabs with steel anchors. The seams between the slabs are tightly filled with cement mortar and embroidered from the side of the ceiling.

Overlappings from ribbed decking are less common, since they require backfilling of trays and complicate the construction of the floor. Due to the complexity of manufacturing and heavy weight one-, two- and three-layer solid decks are even less common.

Figure: 6.9. Floor plan from large panels:

a - from reinforced concrete slabs supported by walls or longitudinal girders; b

Same with transverse walls or girders; c - from slabs supported on

contour; d - the same, based on four points; 1 - plates and panels

overlappings; 2 - longitudinal walls; 3 - transverse walls or purlins; 4 -

frame columns.

Figure: 6.10. Prefabricated slabs (flooring) floors:

a - types of reinforced concrete slabs; b - support and coupling of reinforced concrete

slabs in a brick building; in - the same, in a large-block; 1 - flooring with oval

voids; 2 - flooring with round voids; 3 - ribbed plates; 4 - anchor; five -

solution; 6 - masonry; 7 - inner wall; 8 - outer wall; 9 - cutouts

(filled with masonry or concrete liners); 10 - jumper blocks; eleven-

embedded parts.

In ceilings along transverse girders (Fig. 6.11), ribbed, hollow or solid slabs are used.

Figure: 6.11. Prefabricated slabs by purlins:

1 - ribbed plates; 2 - a lot hollow core slabs; 3 - run; 4 - concrete

pillow; 5 - anchor with a diameter of 16 mm; 6 - transverse and longitudinal walls; 7 -

twisting; 8 - support glass; 9 - concrete; 10 - brick pillar.

The slabs are tied together with wire twisting for mounting loops, and the ceilings with the walls - by anchoring the grommets. Under purlins supported by brickwork, lay the support cushions.

The most progressive are the overlapping of large panels of the size of the room (Fig. 6.12). Such panels represent a part with full factory readiness, completely eliminating the need for plastering or grouting the ceiling. The absence of seams on the ceiling increases the soundproof and architectural advantages of the room.

Good soundproofing qualities are possessed by separate-type ceilings made of rolled, frequently-ribbed slabs laid in pairs (Figure 6.12, b). This slab design provides a simple flooring solution and a smooth ceiling. To ensure sufficient sound insulation between the ribbed floor slabs and the wall panels, soundproofing gaskets (organic-lit strips) are laid. Hip panels represent a reinforced concrete slab 45-60 mm thick, bordered by ribs 135-210 mm high . For better sound insulation such ceilings on the slabs of panels are laid soundproof material (slag, expanded clay, foam stone chips, fiber boards, etc.).

Figure: 6.12. Room-sized panel ceilings:

a - types of panels; b - arrangement of often ribbed plates.

In addition to the considered types of floor slabs, in some areas rich in deposits of high-quality clay, narrow floorings of hollow ceramic stones are used for floors. In areas rich in sand and lime, reinforced-silicate floor slabs are used that do not require cement and are not inferior in strength to reinforced concrete floors. The dimensions of such slabs and floor structures are similar to those of reinforced concrete.

Prefabricated monolithic ceilings (transitional type of ceilings from monolithic to prefabricated) are arranged from ceramic, concrete stones, two-hollow concrete blocks, embedded in concrete. Stones or blocks are laid in rows on formwork boards. Reinforcement is placed in the gap between the rows and concrete is laid, forming reinforced concrete ribs. With the reconstruction of buildings or the presence of only small means of mechanization, spans up to 4 mm can be covered with precast-monolithic ceilings.

Floors.Floors are an integral part of the floors. A rational solution the construction of floors requires special attention, since their cost is close to the cost of the non-existent part of the floor, and labor costs for their installation are 2-4 times higher. The construction of the floor depends on the purpose and nature of the premises where it is installed.

Strict requirements are imposed on interfloor floors in terms of their soundproofing capacity. From the point of view of sound insulation, acoustically homogeneous and non-homogeneous floors are distinguished (Fig. 6.13- 6.14).

Figure: 6.13. Acoustically homogeneous overlap:

1 - ceiling; 2 - bearing plate; 3 - rolled floor on an elastic base.

Acoustically homogeneous ceilings consist of one-, two- and three-layer decks and panels, with a mass that ensures the absorption of airborne noise energy up to the standard level. In this case, the mass of the supporting structure interfloor overlap in residential buildings must be at least 400 kg / sq.m.

The floor covering (clothing), consisting of resiliently soft materials (linoleum on a soft base, fleecy carpet, etc.), is directly glued to the supporting structure and provides damping of impact noise.

Figure: 6.14 . Acoustically inhomogeneous floors:

a, b - type of "floating" floor on an elastic pad; c - when suspended

ceiling; 1-ceiling; 2 - bearing plate; 3 - elastic pad; 4 - floor slab;

5 - roll floor; 6 - screed; 7 - floor on an elastic base; 8 - under-spring

ceiling; 9 - ceiling suspension

Acoustically heterogeneousstructures provide for the construction of floors along the load-bearing part of the floor made of several layers of rigid materials, separated by air gaps or elastic materials. Sound insulation of such ceilings from airborne and impact noise is provided by the entire complex of structural layers.

There are four main types (Fig. 9.4) of acoustically inhomogeneous interfloor structures:

With a laminated floor;

- with split floor;

With split ceiling;

With split floor and ceiling.

The first two types of acoustically inhomogeneous floors are used in residential buildings. Ceilings with a split ceiling are used in civil buildings when wiring is required engineering communications in the space between the ceiling and the ceiling. This solution not only allows you to hide the system of piping and cables, but also increases the sound insulation index up to 60 dB.

Ceilings with split floors and ceilings are arranged in buildings with high soundproofing requirements (recording and television studios)

The construction of a laminated floor is a sequential series of layers laid on the supporting structure of the floor:

Floor clothing;

Leveling layer;

Soundproofing layer.

With the construction of a split floor, its covering is arranged on the basis (prefabricated or monolithic), laid on solid or tape sound-insulating pads, which provide damping of impact and airborne noise.

Special attention for any constructive solution floors are required to be given to the abutment of its layers to walls and partitions (Figure 6.15).

For some ceilings that play the role of external fences (attic, above driveways, cold rooms, etc.), requirements are imposed on their thermal insulation. In this case, the structure of the overlap includes heat-insulating and vapor-insulating layers (Figure 6.16).

The vapor barrier layer must precede the thermal insulation layer in the heat flow path.

Figure: 6.15. Details of floor structures :

L - adjoining walls and partitions; K - mates in doorways; 1- wooden plinth; 2 - soundproofing pad; 3 - a nail; 4 - wooden gasket; board; 6 - cement-sand mortar; 7 - cushioning roofing material; B - concrete cutting; 9 - plinth made of cement-sand mortar; 10- putty; And - asbestos cardboard; 12 - plaster or ceramic tiles; 13 - skirting board made of shaped ceramic tiles; 14 - waterproofing.

The floors are arranged along the load-bearing elements of the floors or along the ground. Ground floors are made in basements, in some rooms on the ground floors, mainly in public buildings

purpose (lobbies, sports halls, in the premises of cultural and domestic purposes, etc.), as well as possible for use in the first floors of low-rise residential buildings (fig. 6.17).

The floor structure consists of a covering (clothing) and a base for it.

Figure 6.16. Floor insulation schemes:

a - attic; 6 - basement; О, Е - flows of heat (0) and steam (E); 1 - bearing element; 2 - vapor barrier layer; 3 - insulation; 4 - leveling screed; 5 - floor covering.

Various products made of wood, rolled and slab synthetic materials, ceramic and tiles made of natural stone are used to cover the floors of civil buildings.

Figure 6.17. Ground floors:

a - planks along the logs; b - from a parquet board; c, d - parquet on the screed; d, f - from polymeric materials and linoleum on the base plate; g, k, m - from ceramic tiles; z, i, l - cement; n - from heat-insulating linoleum; 1 - parquet boards; 2- grooved boards; 3- lags; 4 - gaskets from the board on the roofing layer; 5 - concrete (brick column); 6 underlayment of concrete; 7 - compacted soil; 8 - parquet with mastic; nine - cement strainer: 10 - waterproofing; 11 - linoleum; 12 - sub-floor panel; 13 - ceramic tile; 14 - cement mortar; 15 - a layer of concrete: 16 - gluing waterproofing; 17 - heat-insulating linoleum.

The base of the floors is a flat, hard surface made of bulk materials (concrete, cement, etc.) or prefabricated slabs (fibreboard, gypsum concrete, etc. Fig. 6.18).

Figure: 6.18. Floors over slabs:

a - from grooved boards along the logs; b - from wooden boards; в-д - from parquet; f-g - from linoleum; s, and - from ceramic tiles; k - from parquet; l - from thermal insulation boards; 1 - grooved boards; 2- cushioning roofing material; 3- lags; 4 - mounting soundproofing pads; 5 overlap panel; 6 - wooden board; 7 - parquet on mastic; 8 - cement mortar screed: 9 - solid soundproofing pad; 10 - cast asphalt; 11 - lightweight concrete; 12 - sub-floor panel; 13 - linoleum on mastic; 14 - heat-insulating linoleum; 15 - ceramic tiles on cement mortar; 16 - glued waterproofing; 17 - base panel; 18 - thermal insulation.

Overlappings over basements, driveways and attic floors differ from interfloor by the presence of a layer of insulation and vapor barrier. Vapor barrier that protects the insulation from possible condensation of water vapor penetrating from warm air rooms in the thickness of the overlap, done by sticking 1-2 layers roll material or by coating with hot bitumen. In the ceilings above the driveways, the vapor barrier is laid above the insulation, and in the attic under the insulation.

In the ceilings of the bathrooms between the waterproof clothing of the floor and its base, a waterproofing of two layers of roofing material is laid on bituminous mastic and bending the insulation by 50-100 mm on walls and partitions. The top element of the floor is the covering (clothing). The floor covering must be strong, durable and hygienic.

According to the type of materials and method of execution, the floor covering is divided into monolithic solid) and piece - small-sized, panel board and sheet. Under the covering there is usually a layer, gluing the floor clothes with a screed.

According to the uniformity of the application of floor coverings, the premises of civil buildings are divided into eight groups;

I - living rooms in apartments, hostels, boarding schools, hotels, sanatoriums, rest homes, etc .;

II - chambers and medical premises in health care institutions, sanatoriums, rest homes, children's rooms and corridors in kindergartens;

III - office space for administrative, project and scientific organizations, classrooms, classrooms, laboratories and other premises educational institutions, sports halls, assembly halls, visual reading rooms, etc .;

IV - corridors of civil buildings of all kinds and the foyer are spectacular) buildings, remote from entrance doors more than 20 m;

V kitchens of residential buildings;

VI - children's toilet facilities in kindergartens and hospitals;

VII - sales areas of shops and catering establishments on

on the first floor, more than 20 m away from the entrance doors, as well as halls located on the higher floors;

VIII - corridors of civil buildings, as well as the foyer of spectacular buildings and trading halls located at a distance of less than 20 m from the entrance doors, lobbies, restrooms, showers, bathrooms, washrooms of all types of buildings.

The main types of floor coverings (clothes) of premises are presented in Table 6.2.

Table 6.2.

The main types of floor coverings.

Floor covering type and material	Room group
I	II	III	IV	V	VI	Vii	VIII
Polished concrete							+	+
Mosaic polished							+	+
Polyvinyl acetate-cement concrete polished							+	+
Polyvinyl acetate mastic			+	+	+
From concrete slabs							+	+
From mosaic slabs							+	+
From ceramic plates							+	+
From slag-ceramic slabs							+	+
Boardwalk

Reinforced concrete floors are used in cottage and industrial construction, serve as a ceiling for the lower floor and a floor for the upper one. There are two types of iron concrete slabs: monolithic and prefabricated. Monolithic ones are made directly at the construction site, after pouring they represent a single horizontal plane... Prefabricated - assembled from factory plates, which are mounted one after another, the gaps are filled with mortar, the result is a monolithic surface. The length of the produced boards ranges from 2 to 7.2 m, width from 0.8 to 2 m, height up to 22 cm.

Advantages and disadvantages

Monolithic reinforced concrete floors are one of the most reliable and versatile. Their advantages include:

1. High bearing capacity.
2. Long service life. In the first 50 years, concrete is only gaining strength, such panels can serve several generations of people.
3. The ability to fill floors of any size and shape. The only condition for large rooms is that additional supports are required.
4. Fire safety. The concrete does not burn and does not promote combustion.
5. Lack of seams and transitions.
6. The thickness is less than that of the finished boards.

Disadvantages of a monolithic floor:

1. The complexity of the device. The need to use specialized equipment, which greatly complicates the possibility of independent arrangement.
2. The heavy weight puts a heavy load on the walls and foundations, which makes it impossible to use in some buildings (wooden houses).
3. Seasonality of work. At temperatures below 5 ° C, anti-freeze additives must be used, which significantly increases the cost of the process.
4. Fill continuity. It is not recommended that "old" and "new" concrete meet, as this can lead to cracks.

Often they use ready-made ones at construction sites. These floors have their own advantages:

Factory-made reinforced concrete slabs are a common building material used for floor slabs.

1. Comparative cheapness.
2. Installation speed.
3. Strength and durability.
4. Ease of installation. Plates can be laid with a truck crane with the help of several slingers.
5. Noise isolation. Hollow slabs reduce noise levels.
6. Reliability. Plates are made in the factory, which guarantees quality.

Disadvantages of precast concrete floors:

1. The need to attract lifting equipment.
2. Lower level of rigidity in comparison with a monolithic floor.
3. The presence of spans between the slabs, which requires additional finishing.

Types

Depending on the principles of the device, reinforced concrete floors are of several types:

• ribbed;
• caisson;
• bezel-less.

Casting a monolithic floor will help reduce the amount of used concrete, reduce the pressure on the foundation and walls. It is usually used for the arrangement of industrial buildings when it is necessary to fill large spans.

This monolithic slab includes the slab and the beams running along it (they can go in one or two directions). There are main beams, which rest on columns, walls, and secondary ones, which rest on the main ones. The slabs are supported by secondary beams. The slab rests on the walls or columns with its ribs. Slab widths from 1.8 to 2.8 m, this allows slabs to be made minimum thickness (5-8 cm). It should be noted that the installation of formwork for such a structure is more difficult than when pouring flat slabs, and the ceilings are ribbed and require plasterboard sheathing. The thickness of the ribbed slab is 5-6 cm less than the usual one. Ribbed slabs monolithic slabs 2 times more profitable than usual.

Coffered floor scheme.

When pouring large areas coffered ceiling is also popular. In such a ceiling, the beams are placed in two directions (perpendicular) with a step of up to 1.5 m, a monolithic concrete slab is located on top. The beams should have a height of at least 1/20 of the span, the thickness of the slab should be from 4 cm.

The lightness of the reinforced concrete floor is given by the voids between the ribs, which are formed using plastic cavity-forming molds, which perform the function of removable or non-removable formwork. The device of the coffered floor allows you to save up to 55% of the material in comparison with flat slabs. Caissons are also called often-ribbed, frequent-girder, or wafer monolithic ceilings.

Beamless ceilings are made in rooms with large uniform loads and when they want to get smooth ceilings, convenient for mounting suspended vehicles, wiring communications. These can be multi-storey warehouses, refrigerators, meat processing plants. Beamless slab is a flat reinforced concrete continuous panel. It rests on columns or mushroom-shaped capitals. The peculiarity of this design is that the load is transmitted through the panel directly to the columns. The grid of columns is made in a square or rectangular shape with a step of 6 m. At the top, the columns expand to form capitals. The bezel-less design has a number of advantages: improved sanitary indicators, easier ventilation of premises, easier laying of communications, reduced area requiring additional finishing (ceilings are smooth), the ceiling height is lower than when using ribbed or coffered structures, which saves on building maintenance (heating , cooling).

Manufacturing technology

For pouring monolithic structures, it is necessary to prepare the following materials: reinforcement, cement (grade from M-400), crushed stone, sand, an apparatus for welding reinforcement, boards for formwork, an electric tool (for cutting boards, reinforcement). When the material is ready, you can start assembling the formwork, its bottom can be made of boards 3-4 cm thick, or waterproof plywood 2 cm thick, boards 2-3 cm thick are used for the side walls.If boards with slots, they must be covered with a film , this will prevent the solution from leaking out.

The first thing to do is to lay the bottom panels; cross beams and supports are used for installation. The distance between the posts (supports) is 1-1.2 m. After that, the side walls are mounted. The formwork must be strong, be placed strictly horizontally, the bottom can be covered with foil or roofing felt, this will give a smooth surface, remove minor irregularities of the boards.

The calculation of the reinforcement in a reinforced concrete floor must be carried out by a specialist. It is recommended to use reinforcement with a diameter of 8-14 mm (depending on the expected loads).

Reinforcement is carried out in two balls, the lower one is installed on plastic supports. A mesh is made of reinforcement with a step of 150-200 mm. The reinforcement is attached to the mesh soft wire... The reinforcement is taken in one piece, if the length is small, then an additional piece is attached with an overlap equal to 40 times the diameter of the rod. The joints are staggered. The grids are connected at the edges with u-shaped reinforcements. After pouring, the frame must be hidden by a ball of concrete from 2 cm.

Additional reinforcement is carried out depending on the pouring area. It is made in separate pieces of reinforcement 40-200 cm long. The lower mesh must be reinforced in the opening, the upper one - above the load-bearing walls. In places where columns are supported, the reinforcement requires separate volumetric reinforcing elements.

To fill the floors, concrete of the M400 brand is used (1 part concrete, 2 - sand, crushed stone -4, water). The concrete is poured into the formwork, starting in one corner and ending in the opposite. A deep vibrator should be used when laying to help remove voids from the concrete. A reinforced concrete slab is poured without interruptions, 8-12 cm thick. After pouring, the surface is leveled with devices similar to mops.

It is possible to remove the formwork in 2-3 weeks after pouring, then the slab gains 80% of its strength. If the formwork is removed earlier, then the supports are left. The plates can be used after 28 days (after complete drying). To avoid drying out and the appearance of cracks, the first week after pouring the concrete must be regularly moistened, watered with water. Sometimes the surface is covered with burlap or foil for additional moisture retention.

When building a house, any developer faces the question of choosing an interfloor overlap. The most common are three types of floors - timber, monolithic reinforced concrete and precast reinforced concrete, mounted from flat hollow core slabs. It is about this type of flooring, as the most popular and practical for low-rise construction, that will be discussed in this material. From this about interfloor floors in a private house, you will learn:

• What is the difference between hollow-core floor slabs (PC) and floor slabs made by formless molding (PB).
• How to lay floors correctly.
• How to avoid mistakes during installation.
• How to store floor slabs.

How to choose a hollow core slab

At first glance at hollow ceilings it may seem that they differ from each other only in length, thickness and width. But the technical characteristics of hollow floor slabs are much broader and are detailed in GOST 9561-91.

Hollow floor slab, private house.

Hollow interfloor slabs differ in the way of reinforcement. Moreover, reinforcement (depending on the type of slabs) can be performed using prestressed reinforcement or without prestressed reinforcement. Overlappings with prestressed working reinforcement are more often used.

When choosing floor slabs, you should pay attention to this important point, as the permissible number of sides on which they can be supported. ... Usually, you can only support on two short sides, but some types of slabs can be supported on three and four sides.

• PB. Provides support on both sides;
• 1pc. Thickness - 220 mm. The diameter of the round voids is 159 mm. Supports only two sides;
• 1PCT. Having the same dimensions, it can be supported on three sides;
• 1PCK. Can be supported on four sides.

Also, floor slabs differ in the manufacturing method. Often there is a dispute about which to prefer - PC or PB.

Andrey164 FORUMHOUSE user

It's time to block the basement of the building with floor slabs, but I just can't determine what to choose - PC or PB, PB has a better surface finish than PC, but I heard that PB are used only in monolithic-frame houses and country houses, and the end such a slab should not be loaded with a wall.

Sasha1983 FORUMHOUSE user

The main difference between the plates lies in the technology of their manufacture.

PC (with a thickness of 160 to 260 mm and a typical bearing capacity of 800 kg / sq. M.) Is cast in the formwork. Panels of the PB brand (with a thickness of 160 mm to 330 mm and a typical bearing capacity of 800 kg / sq.m) are manufactured by the method of non-formwork continuous casting (this allows obtaining a smoother and more even surface than that of PC panels). PB is also called extruder.

PB, due to the prestressing of the compressed and stretched zones (prestressing of the reinforcement is done at any length of the slab), are less susceptible to cracking than PCs. PCs with a length of up to 4.2 meters can be produced without prestressed reinforcement and have a greater free deflection than PB.

At the request of the customer, PB can be cut to individual specified dimensions (from 1.8 to 9 meters, etc.). They can also be cut lengthwise and into separate longitudinal elements, as well as an oblique cut at an angle of 30-90 degrees, without losing its bearing capacity. This greatly simplifies the layout of such floor slabs at the construction site and provides more freedom to the designer, because the dimensions of the building box and load-bearing walls not tied to standard PC sizes.

When choosing interfloor PC slabs (more than 4.2 meters long), it is important to remember this feature - they are prestressed with special stops at the ends of the slab. If you cut off the end of the PC, then the stop (cut off together with the end of the PC and vertical reinforcement) will not work. Accordingly, the working reinforcement will cling to concrete only with its lateral surface. This will significantly reduce the load-bearing capacity of the slab.

Despite the higher quality smooth surface, good geometry, lower weight and high bearing capacity, this moment should be taken into account when choosing a PB. Hollow holes in the PC (depending on the width of the slab, with a diameter of 114 to 203 mm) allow you to easily punch a hole in it for sewer riser, with a diameter of 100 mm. While the size of the hollow hole in the PB is 60 mm. Therefore, to break through through hole in the PB brand panel (so as not to damage the reinforcement), you should check with the manufacturer in advance how this is best done.

Floor slabs for a private house: installation features

PB (unlike PC) do not have mounting loops (or you have to pay extra for their installation), which can complicate their loading, unloading and installation.

It is not recommended to use the "popular" method of PB installation, when the fastening hooks cling to the end of the hollow hole. In this case, there is a high probability that the hook will rip out of the hole due to the destruction of the end of the plate, or the hook will simply slip off. This will cause the slab to fall. Also, at your own peril and risk, you can apply a method in which scrap is inserted into the hollow holes of the PB (two scrap on one side of the slab) and hooks cling to them.

Installation of PB plates is allowed only with the use of soft rods or a special traverse.

ProgC FORUMHOUSE user

To pull the pull out from under the slab, while laying it, leave a 2 cm gap to the adjacent slab. Then we move the already laid slab with a crowbar to the neighboring one.

Max_im FORUMHOUSE user

Personal experience: I laid the slabs at my construction site using this method. The gap left at 3 cm. The slabs lay on a cement-sand mixture 2 cm thick. The mixture served as a lubricant, and the slabs were easily moved with a crowbar to the distance I needed.

Also, when installing floor slabs, it is necessary to observe the calculated values \u200b\u200bof the minimum support depth of the slab. The following numbers can be used as a guideline:

• brick wall, the minimum bearing depth is 8 cm, the maximum bearing depth is 16 cm;
• reinforced concrete - 7 cm, maximum bearing depth - 12 cm;
• gas and foam concrete blocks - at least 10-12 cm, optimal depth support - 15 cm;
• steel structures - 7 cm.

It is not recommended to support the floor slab more than 20 cm, because when the depth of support increases, it begins to "work" like a pinched beam. When laying floor panels on walls built of their gas and foam concrete blocks, it is necessary to install a reinforced reinforced concrete armored belt, which is described in detail in the article:. Read also our article, which tells in detail,. We wish you to successfully apply the acquired knowledge on your construction sites!

It is recommended to seal the ends of the hollow holes before starting the installation of the slabs. The voids are sealed to prevent water from getting inside the panel. It also increases the strength at the ends of the slabs (this is more related to PC than to PB) in the case of bearing partitions on them. The voids can be repaired by inserting half a brick into them and covering the gap with a layer of concrete. Typically, voids are sealed to a depth of at least 12-15 cm.

If water does get inside the plates, it must be removed. For this, a hole is drilled in the panel, in the "void", from below, through which water can flow out. This is especially important if the ceilings have already been laid, and the house went into the winter without a roof. Water in frost can freeze inside the hollow hole (since it has nowhere to flow out) and break the slab.

Sergey Perm FORUMHOUSE user

The slabs laid on the ceiling lay for a whole year. I specially drilled holes in the "voids" with a puncher, a lot of water came out. Each channel must be drilled.

Before laying the floor slabs, it is necessary to choose a crane with the required lifting capacity. It is important to consider the accessibility of access roads, the maximum possible boom reach at the truck crane and the permissible load weight. And also calculate the ability to lay floor panels not from one point, but from two sides of the house.

zumpf FORUMHOUSE user

The surface on which the floor slab is laid must be flat, free of debris. Before laying the panel "spreads out" cement mix, the so-called mortar "bed", 2 cm thick. This will ensure its reliable adhesion to the walls or armored belt. Also, before installing the panels and before applying the mortar to the wall, you can lay a reinforcing bar with a diameter of 10-12 mm.

This method will allow you to strictly control the verticality of mixing of all slabs during their laying (since the panel will not go down below the bar). The rod will not allow it to completely squeeze out the cement mortar from under itself and lie down "dry". It is not allowed to place the slabs "steps". Depending on the length of the slabs, the divergence of the ends should not exceed 8-12 mm.

A serious mistake during laying is the overlap of two spans with one slab at once, i.e. it rests on three walls. Because of this, loads that are not provided for by the reinforcement scheme appear in it, and under certain, unfavorable circumstances, it can crack.

If such a layout cannot be avoided, to relieve stress, a grinder is cut along the upper surface of the panels, just above the middle partition (wall).

Another point to focus on is how to block the flight of stairs between the floor slabs, if there is nothing to support them. In this case, two channels can be run parallel to the slabs, and one can be placed across, along the edge of the opening, to tie the reinforcement cage in the form of a mesh with a cell of 20 cm and a bar diameter of 8 mm, etc. Place the formwork and fill the monolithic area. It is not necessary to tie the channel to the floor slabs. In this case, they rest on two short sides and are not subject to loads from the support unit of the staircase.

How to properly store floor slabs on the site

Ideally, if the panels were brought to the site, they must be installed immediately. If for some reason this cannot be done, the question arises: how to store them correctly.

For storage of slabs, it is necessary to prepare in advance a firm and level platform. You can't just put them on the ground. In this case, the lower slab can lean on the ground, and, due to uneven loading, under the weight of the upper slabs, it will break.

Products should be stacked no more than 8-10 pcs. Moreover, spacers are placed under the bottom row (from a bar of 200x200 mm, etc.), and all subsequent rows are placed through spacers - an inch board 25 mm thick. The gaskets should be located no further than 30-45 cm from the ends of the plates, and they should be positioned strictly vertically above each other. This will ensure an even redistribution of the load.

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The main elements of the floor are load-bearing structures, which can be made of beams with liners, decks and panels. In large-panel houses, as a rule, they are used floor panels of various designs the size of a room. The nomenclature of the II-03-02 catalog includes prestressed floor panels with a height of 22 cm in accordance with GOST 9561-60 with horizontal oval and vertical voids made of heavy and light concrete. Vertical voids are formed by liners from pipes with a channel welded from below. Until January 1, 1963, the use of panels with round voids is allowed. Floor slabs over 5 m are allowed only prestressed. In the presence of equipment for manufacturing, two-layer panels and floorings made on concreting combines are allowed.

Floor panels are taken in four sizes in width - 80.100, 120, 160 cm and are designed for two standard loads - 600 and 900 kg / m 2 (PO and PTO).

The panels are reinforced with cold-drawn carbon steel wire or low-alloy hot-rolled steel of periodic profile of grades 35 GS, 25 G2S, 30HG2S, mounting loops from St. 3. Panels reinforced with cold drawn wire should be made of 300 grade heavy concrete; reinforced with steel 35 ГС, 25 Г2С, 30ХГ2С - from heavy concrete of grade 200.

Panels should be manufactured, as a rule, with one butt-end sealed during the molding process.

Table 1. Indicators of floor panels

Panel brand	Dimensions in mm		Weight in kg	Panel brand	Dimensions in mm		Weight in kg
	length	width			length	width
Software 59-16	5860	1590	2280	PV 59-16	5860	1590	2330
PTO 59-16				PTV 59-16
Software 59-12		1190	1710	PV 59-12		1190	1750
PTO 59-12				G1TV 59-12
Software 63-10	6260	990	1530	PV 63-10	6260	990	1550
PTO 63-10				PTV 63-10
Software 59-10	5860		1400	HB 59-10	5860		1450
PTO 59-10				PTV 59-10
Software 47-10	4660	9	1145	PV 47-10	4660		1150
PTO 47-10				PTV 47-10
Software 63-8	6260	790	1180	? B 63-8	6260	790	1240
PTO 63-8				PTV 63-8
Software 47-8	4660		885	? B 47-8	4660		920
PTO 47-8				PTV 47-8

For 3-5-storey buildings, the II-03-02 catalog recommends panels of the type PO, PTO, PV and PTV - 59-16; 59-12 and 59-10, other types of panels are intended for civil construction.

Permissible deviations from the design dimensions · in length ± 5 mm, in width + 5-10 mm in height ± 3 mm, in a protective layer ± 2 mm.

For 1-2-storey construction, the catalog provides for the use of:

• flat slabs 318 and 258 cm long, 79 cm wide, reinforced with meshes;
• ribbed slabs 398 cm long, 39.5 cm wide, reinforced with nets and frames;
• t-beams, reinforced with frames (for filling from gypsum concrete and lightweight concrete slabs).

The catalog allows for 1-2-storey residential construction the use of products intended for 3-5-storey buildings.

In prefabricated construction, it is possible to use other rational structures of floor panels, which provide a decrease in the weight of load-bearing structures, a decrease in material consumption, cost and labor intensity. The characteristics of some panels are given in table. 2.

Floor slabs are horizontal structures that perform the function of interfloor or attic partitions installed between the roof and top floor houses. In modern construction, they usually resort to installing concrete floors, and it does not matter at all how many levels the building has. In this article, we will look at the types and sizes of floor slabs that are most often used on construction sites. These products make up the bulk of the products that are manufactured at the precast concrete factories.

Design purpose

Supporting structures are made of heavy or lightweight concrete, and their structure is reinforced with reinforcement, which gives strength to the products. In today's market building materials all standard types Reinforced concrete slabs, which can be divided into several categories depending on their width, length, weight, and others at least important parametersaffecting the main characteristics of products.

The most common method for classifying concrete panels is to subdivide them according to their cross section. There are also a few more distinctive characteristics, which we will definitely consider in our article.

Hollow-core reinforced concrete panels PC

These are one of the most common types of products manufactured in precast concrete factories, which are equally well suited for the construction of a private and multi-storey building. Also, hollow-core PC products are widely used in the construction of massive industrial buildings, with their help they provide protection for heating mains.

Hollow-core floor slabs are characterized by the presence of voids

The smooth flat surface, which the round-hollow concrete panels have, allows you to mount reliable floors between floors that can withstand impressive loads. This design is equipped with cavities with cross-sections various shapes and diameter, which are:

• round;
• oval;
• semicircular.

Technological voids, which are filled with air during the installation process, are in high demand due to this feature, which speaks of the advantages of this particular block configuration. The indisputable advantages of a PC include:

1. Significant savings in raw materials, which allows you to reduce the cost of the finished product.
2. High coefficient of thermal and noise insulation, which improves performance characteristics the buildings.
3. Hollow-core panels are an excellent solution for laying communication lines (wires, pipes).

Reinforced concrete structures of this type can be conditionally divided into subgroups, and then we will tell you what kind of hollow-core floors are and by what criteria they can be attributed to one or another subgroup. This information will be important for the right choice material depending technological requirements construction.

The slabs differ in the way they are installed: 1 PCT has three support sides, while 1 PCT can be installed on all four sides.

It is also necessary to pay attention to the size of the internal voids - the smaller the diameter of the holes, the more durable and stronger the hollow-core panels. For example, samples 2PKT and 1 PKK have similar width, thickness, length and number of support sides, but in the first case the diameter of the hollow holes is 140 mm, and in the second - 159 mm.

As for the strength of products manufactured by factories, its performance is directly affected by the thickness, which averages 22 cm.There are also more massive panels with a thickness of 30 cm, and when pouring lightweight samples, this parameter is observed within 16 cm, while in most cases lightweight concrete is used.

We should also mention the bearing capacity of PC products. For the most part, PC hollow-core floors, according to generally accepted standards, withstand a load of 800 kg / m2... For the construction of massive industrial buildings, slabs made of stressed concrete are used; this parameter is increased to a design value of 1200-1250 kg / m2. The design load is a weight that exceeds the same value for the product itself.

Manufacturers release reinforced concrete panels standard sizes, but sometimes the parameters can vary significantly. The length of the PC can vary in the range of 1.5m - 1.6m, and their widths are 1m, 1.2m, 1.5m and 1.8m... The lightest and smallest slabs weigh less than half a ton, while the heaviest and heaviest specimens weigh 4,000 kg.

Hollow-core structures are very convenient to use, because the developer always has the opportunity to select the material of the required size, and this is another secret of the popularity of this product. Having familiarized ourselves with the most common PC products, which include hollow core slabs, having considered their types and sizes, we suggest switching to other products of a similar purpose.

Prefabricated ribbed (U-shaped) panels

These reinforced concrete structures got their name due to a special configuration with two longitudinal stiffeners, and they are used in the construction of non-residential premises and as load-bearing elements for laying heating plants and water supply networks. To strengthen reinforced concrete products at the stage of their pouring, reinforcement is carried out, which, coupled with a special shape, leads to savings in raw materials, gives them special strength and gives them resistance to bending. It is not customary to install them as jumpers between floors for a residential building, since here you will have to face an unaesthetic ceiling, which is quite difficult to supply with communications and sheathe cladding. It also has its own subspecies, let's consider what differences the products have within the same group.

Ribbed slab structure is highly durable

The first and main distinguishing feature of U-shaped structures is their size, or rather, in terms of height, which is 30 or 40 cm. In the first case, we are faced with products that are used in the construction of public buildings and as jumpers between the upper floor of the house and the attic. For massive large-scale commercial and industrial buildings, slabs with a height of 40 cm are usually chosen.The width of ribbed floors can be 1.5 or 3 m (for more durable samples), and their weight ranges from 1.5 to 3 tons (in rare cases up to 7 t). Precast ribbed concrete slabs are characterized by the following lengths:

• 12 m.
• 18 m (rare).

Solid additional structures

If it is necessary to obtain a particularly strong overlap between the floors of a house, they resort to the help of solid jumpers, since they can easily withstand a load of 1000-3000 kgf / m2, and they are used mainly during installation multi-storey buildings.

Solid lintels allow the installation of a high-strength overlap

Such products have drawbacks, because their weight for relatively small dimensions is quite impressive: standard samples weigh from 600 kg to 1500 kg... They also have weak thermal and noise insulation indicators, which does not allow them to adequately compete with hollow PC samples. The length of this type of panel ranges from 1.8 m to 5 m, and the thickness is 12 or 16 cm.

Monolithic structures

Previous and given species panels have the same scope and are installed where there is a need to create a strong structure that can withstand overload. Such a partition does not contain cavities and is created directly at the construction site according to the available accurate calculations, therefore it can take any configuration and dimensions, limited only by the area of \u200b\u200bthe object being built.

In the article, we described in detail what types of floor panels are, what standard sizes they have and where they are used most often, so you can select the necessary products for the upcoming construction and get a durable durable constructionthat can serve you for at least a century.