Overlapping and its types. Cover installation. Ceilings are prefabricated-monolithic, beam ceilings of the Marco system, the lightest ceilings in Russia Ceiling 100 mm

Reinforced concrete floors are the most reliable and durable and therefore are currently widely used in civil engineering.

According to the device they are:

■ monolithic,

■ prefabricated and

■ prefabricated monolithic.

The simplest type of monolithic reinforced concrete floor is smooth single-span slab. Such an overlap, having a thickness of 60 ... 100 mm, depending on the load and the span, is used for rooms with side sizes up to 3 m.

For large spans suit beam ceilings, which can be:

■ prefabricated and

■ monolithic.

So, if it is necessary to block a room measuring 8 x 18 m (Fig. 6.4), beams are arranged with a span of 8 m in increments of 6 m.

Rice. 6.4. Reinforced concrete monolithic ribbed coating: 1 - main beam, 2 - secondary beam, 3 - slab.

These beams are called main. On them, after 1.5 ... 2 m, they arrange the so-called secondary beams having a span of 6 m. A plate with a thickness of 60 ... 100 mm is laid on top. Thus, the design of the overlap is ribbed. The height of the main beam can approximately be taken as 1/12 ... 1/16 of the span, and the width 1/8 ... 1/12 of the distance between the axes. In ribbed ceilings, 50 ... 70% of concrete is spent on the slab. If this species overlapping is made monolithic, it is necessary to carry out formwork in a short time, carry out reinforcing works and concrete placement. This is one of the disadvantages of this type of overlap.

If the height of the main and secondary beams is assumed to be the same, then this type of flooring is called coffered(Fig. 6.5).

Rice. 6.5. General view of the reinforced concrete monolithic coffered ceiling.

Their use is mainly due to the requirements of the solution of the interior of the room.

Prefabricated reinforced concrete ribbed ceilings are much more economical than monolithic ones, as they allow to increase the industrialization of construction, reduce labor costs and the timing of construction and installation works. An important requirement device prefabricated floors is to reduce the number of mounting elements. The best option serves the one when slabs the size of a room are used.

A special type of reinforced concrete beam ceiling is a ceiling along beams located in one direction with a step of 600 ... 1000 mm, and filling between them from gypsum or lightweight concrete slabs reinforced with wooden bar frames (for interfloor ceilings) or welded steel mesh(for attic).

Often, instead of rolling, double-hollow liner stones 250 mm high and 195 mm long are also used. The gaps between the stones and beams are carefully sealed with cement mortar, which helps to increase the rigidity of the ceiling and sound insulation.

Elements of beam ceilings have a relatively small mass, and therefore they are used in the construction of buildings equipped with light-duty cranes.

Beamless monolithic reinforced concrete floors(Fig. 6.6.4) are a slab 150 ... 200 mm thick, resting directly on the columns, in the upper part of which there are thickenings called capitals.

Rice. 6.6.4. Reinforced concrete monolithic beamless ceiling:

a - general view, b - scheme of supporting the slab on the column, 1 - slab, 2 - capital, 3 - column.

The grid of columns with a beamless ceiling is taken to be square or close to a square with a side size of 5 ... 6 m. The device of prefabricated beamless ceilings is very effective.

Most widely used in civil engineering slab ceilings. The main load-bearing elements of slab floors are different kinds reinforced concrete decking panels made of concrete.

Depending on the structural schemes of buildings, they are (Fig. 6.7):

■ from panels resting with their ends on longitudinal load-bearing walls or on girders laid along the building;

■ from panels resting with their ends on transverse walls or girders laid across the building;

■ from panels supported by load-bearing walls or girders on three or four sides;

■ from panels resting at four corners on the frame columns.

Rice. 6.7. Structural schemes slab floors:

a - with longitudinal lines of supports, b - c transverse lines supports, c - supported on three or four sides (along the contour), d - supported on four points (corners), 1 - floor panels based on load-bearing walls, 2 - internal longitudinal or transverse load-bearing wall, 3 - external load-bearing wall, 4 - floor panel supported by purlins, 5 - purlins, 6 - columns, 7 - room-sized floor panel supported by columns, 8 - external non-bearing wall.

The minimum depth of decking in brick walls is 120 mm, in block and panel walls - 100 mm on each side.

Precast concrete floor slabs during their installation, they are rigidly embedded in the walls with the help of anchors and fastened together by welded or reinforcing ties. The seams between the plates are monolithic with mortar. Thus, rather rigid horizontal disks are obtained, which increase the overall stability of buildings.

Floor slabs are:

■ solid section,

■ ribbed (Fig. 6.8) and

■ hollow (Fig. 6.9).

Rice. 6.8. Prefabricated reinforced concrete floor panels: a - solid single-layer, b - solid two-layer, c - often ribbed with ribs up, d - often ribbed from two vibro-rolled shells, d - tent with ribs along the contour, 1.2 - mounting loops.

Rice. 6.9. Hollow core floor panels: a - with round voids, b - panels manufactured on plants with concreting combines, c - panels with oval voids, 1 - top layer, 2 - middle layer, 3 - bottom layer.

Solid single layer panels represent reinforced concrete slab of constant section with a bottom surface ready for painting, and an even upper surface prepared for flooring, have a thickness of 100 ... 120 mm with a multilayer floor structure and 140 mm with a sticker on a linoleum slab on an elastic basis. For spans of more than 6 m, single-layer continuous prestressed slabs 140 mm thick are used, in which sound insulation from airborne noise provided by the mass of the plate itself.

Also apply layered solid panels(see Fig. 6.8, b), which are a reinforced concrete slab of constant cross section, the lower layer of which is made of durable concrete, where tensile reinforcement is located, and the upper layer is made of lighter and less durable concrete. These plates can also be three-layer.

Ribbed panels can be with ribs located both up and down. When the ribs are located upwards, it is advisable to assemble the structure of the slab and floor at the factory, which increases the coefficient of prefabrication and reduces labor costs at the construction site.

To increase the soundproofing ability of the ceiling, layered structures are used, in which clean floors are arranged along soundproofing layers.

On fig. 6.10, a - e shows diagrams of layered floors.

Rice. 6.10. Structural schemes of floors: a - with a layered floor covering, b - with a separate floor, c - with a separate ceiling, d - a separate floor of two load-bearing panels, e - with a separate ceiling and a layered floor covering, 1 - load-bearing floor panel, 2 - warm soundproofing layered floor, 3 - floor covering, 4 - split floor base panel, 5 - split ceiling panel, b - load-bearing floor panel.

So, the device of an air gap (Fig. 6.10, d) with a thickness of 80 ... 100 mm, located between two bearing panels or between the bearing part of the ceiling and the structure of the acoustic ceiling (Fig. 6.10, c, e) or floor (Fig. 6.10, b), allows you to provide the necessary soundproofing ability of the floor. To do this, use ceilings from panels with ribs down and a separate ceiling device.

Effective in this regard are often ribbed panels, consisting from two vibro-rolled shells(see Fig. 6.8, d), one of which forms the base for a clean floor, and the other serves as a ceiling. A continuous air gap and soundproof gaskets between the slabs provide the necessary soundproofing of the ceiling.

Hollow core panels widely used for floor coverings. They are most often made from concrete of classes B15 and B25 with a length of 2.4 to 6.4 m and a width of 0.8 to 2.4 m with a thickness of 220 mm.

Panels come with

■ round and

■ oval voids.

Slabs with oval voids are somewhat more economical in terms of concrete consumption, but laborious to manufacture. It must be borne in mind that the cost of hollow core panels is relatively high.

Also apply hipped panels(see Fig. 6.8, e), which look like a slab, framed along the contour with ribs facing down in the form of a cornice. Manufactured in the size of a room, they allow to exclude crossbars and other beam elements from the structural scheme of the building, and due to their small thickness they allow to reduce the height of the floor without reducing the height of the room.

During the construction of public buildings, it often becomes necessary to install a floor with spans of 9, 12 and 15 m. For this, they use:

■ ribbed prestressed slabs 9 m long, 1.5 m wide and 0.4 m rib high (Fig. 6.11, a);

■ prestressed panels type TT-12 and TT-15 for spans of 12 and 15 m, respectively (Fig. 6.11, b, c).

Such slabs make it possible to increase the prefabrication of construction and reduce labor costs for the installation of floors.

Rice. 6.11. Floor slabs for spans of 9, 12 and 15 m: 1 - mounting loops, 2 - longitudinal ribs, 3 - transverse ribs.

The MARKO-STANDARD ceiling was the first Russian prefabricated monolithic ceiling, which was widely used in residential, civil and industrial construction.

Progressive prefabricated monolithic technology for the construction of reinforced concrete interfloor light floors has been used in Europe for more than 70 years. Known in Russia prefabricated monolithic floors YTONG, polish overlaps TERIVA (TERIVA), Belarusian overlaps DAH . Overlap MARCO retained all the best qualities of European floors and added a new one -square meter of Russian flooring is 80-100kg lighter than European .

Scheme of the MARKO-STANDARD beam with additional longitudinal reinforcement

The dimensions of the cross-section of the concrete element of the beam are 40x120 mm, the concrete strength class is not lower than B20. To increase the bearing capacity of the ceiling, the concrete element can be reinforced with additional longitudinal reinforcement with a diameter of 6 to 16 mm. All reinforcement of the beams is a rolled reinforcing bar welded with a periodic profile of classes A500C and B500C according to GOST R 52544-2006 with a yield strength of at least 500N/mm2

In February 2013, our priority in the development of lightweight ceilings was confirmed by another patent. In the construction of these floors, the base of the beam is not a concrete bar, but a thin-walled C-shaped lightweight profile. Beams with this profile weigh three times lighter than concrete beams. New beams can be joined to each other at an angle. These features made it possible to significantly reduce the laboriousness of the installation of ceilings, to cover spans up to 12 meters, to form balconies, consoles with the help of ceilings, to arrange openings of various configurations in a monolithic slab. Working with profile beams is in many ways similar to working with a drywall profile. Floor buyers quickly appreciated the benefits of the new floor.

In October 2013 we received a patent on the beam, which allows you to use any building blocks in the ceilings. Developers no longer need to purchase and import special blocks for floors. Now it is enough to purchase an additional number of blocks from which the walls of the house are built and order only beams from our company. The new cover has been named. The name once again emphasizes the versatility of the proposed design. There are building blocks in any region of Russia. This means. that anywhere in Russia today builders can install MARCO ceilings.

Floor beams in production. The photo clearly shows the additional reinforcement of the beams..

Beams are manufactured on special heated vibration stands. You can buy one of these stands from us and start your own production of concrete floor beams

Floor blocks are made of polystyrene concrete with a density of less than 400 kg/m 3 .
The weight of the blocks does not exceed 6 kg. Blocks and beams play the role of fixed formwork, and take on the loads that occur during concreting.

Technical documentation for blocks and floor beams agreed with the Research, Design and Technological Institute of Concrete and Reinforced Concrete NIIZhB and registered GOSSTANDARD.

According to the results of certification testsblocks are classified as low-hazard non-combustible materials with low smoke-generating ability. A positive sanitary and epidemiological conclusion was obtained for MARKO polystyrene concrete.

For the production of floor blocks, a high-performance vibrating stand is used. Vibrostand performance - 3000 blocks per shift. This allows you to complete blocks of 350 m 2 floors.
MARKO-STANDARD technology provides four overlap thicknesses: 200, 250, 300 and 350 mm.

Floor plan MARKO-STANDARD 200 mm thick

Scheme of the thinnest overlap of the MARCO system SMP-200 shown in the figure.

Scheme of the MARKO floor with a thickness of 300 mm, in which an additional slab with a thickness of 50 mm is used.

The Russian MARKO system for thicknesses greater than 250 mm uses additional foam plates.

The slabs are glued to the top surface of the blocks with any cement-based tile adhesive. This solution allows the use of a single nomenclature of blocks.

Overlapping MARKO 350 mm thick with additional insulation

Scheme of installation of ceilings without a separate monolithic belt

Installation of prefabricated monolithic ceiling MARKO-STANDARD . The beams are suspended above the Yitong aerated concrete wall with a gap of 40-50 mm. This made it possible to form a monolithic belt simultaneously with the concreting of the floor.

Usage prefabricated monolithic ceilings MARKO allows abandon the obligatory device of a separate monolithic belt (seismic belt, armored belt) on walls made of low-bearing materials (aerated concrete, foam concrete, MARKO polystyrene concrete, expanded clay concrete, etc.). Due to simple technological methods, a monolithic belt is formed simultaneously with the concreting of the floor slab.

To do this, floor beams are hung above the wall with a gap of 40-50 mm. After filling the gap with concrete, a full-fledged monolithic belt will form on the wall. Such a method of installing fixed formwork for overlapping and seismic belt significantly reduces the cost of construction and reduces the time.

The photo clearly shows how this scheme is implemented at the construction site. A well-made monolithic belt evenly distributes the load along the entire perimeter of the walls and prevents the formation of cracks in case of uneven shrinkage of the foundation.

Photo

Overlap index tiya	Thickness mm	Own- weight kg	Index block	Thickness dobor- Noah plates mm	Covered spans and allowable payloads
Overlap index tiya	Thickness mm	Own- weight kg	Index block	Thickness dobor- Noah plates mm	Pro- years	Pro- years	Pro- years	Pro- years
SMP-200	200	230 - 240	BP-150	-	9	-	8	-	6	500	4	1000
SMP-250	250	260 - 268	BP-200	-	9	-	8	-	6	600	4	1000
SMP-300	300	300 - 308	BP-200	50	9	-	8	400	6	1000	4	1000
SMP-350	350	340 - 348	BP-200	100	9	200	8	700	6	1000	4	100

The table shows the average characteristics of all options SMP MARCO. Of particular interest here is low weight. The combination of low weight with high bearing capacity is a clear competitive advantage SMP MARCO.

There are no overlaps lighter than MARCO in Russia.

The cross section of a concrete element obtained as a result of concreting is similar in design to a factory-made ribbed slab. Each rib includes a beam and a concrete core. Cross section shapeconcrete corepresented in the diagram.

Low block weight allowed to increase the loading rate of the car. A standard body with a length of 12 m can accommodate 220-250 sq. m of floors. When transporting over a distance of up to 1000 km, the cost of delivery of one square meter designs does not exceed 200 rubles.

Photo

For finishing ceilings from SMP, you can use drywall on metal or wooden frame, plastic panels, plaster, suspended ceilings such as Amstrong, wooden lining and other finishing materials.

Prefabricated monolithic ceilings are successfully used for the reconstruction of industrial buildings.

Construction company specialists Columbus develop project documentation for prefabricated monolithic floors for you, offer a rational floor plan, complete a drawing of the floor, show a photo of the floor, prepare recommendations for installation, deliver the SMP to construction site, install if necessary.

Our experience shows - in some cases, only the SMP allows you to reinforce the floors.

Photo

SMPs are successfully used in the construction of buildings according to classical and modern technologies, simprolit, durisol,Velox, itong.

Particularly interesting is the experience of replacing floors according to wooden beams on the SMP. In this case, the task of strengthening the structure (increasing the bearing capacity) is often posed. As a rule, the thickness of the monolithic intermediate floors obtained as a result of the reconstruction is less than the thickness of the original wooden floor. At the same time, the monolithic floor is connected to the load-bearing walls and strengthens them.

Photo

If necessary beams and blocks are easy to modify directly on the construction site. This feature is often used for bay windows and rooms with complex wall configurations.

Production allows to ensure the accuracy of the manufacture of beams within one centimeter, but the poor accuracy of the walls often leads to the need to refine the beams on the construction site.

Photo

Photo

Photo of the ground floor Igor Borisovich Chubais, which the construction company Columbus built in 2006. There are two SMPs between floors in the house, in which beams up to 8 meters long.

WHEN LAYING THE FOUNDATION OF THE HOUSE WAS CONSCIENTED

THE USE OF ASSEMBLY-MONOLITHIC FLOORS ALLOWS:

Reduce the weight of intermediate floors compared to hollow core slabs by 30% and Twice compared to a monolith.
Conduct installation without using a crane
Exclude the device of a separate monolithic belt on walls made of weakly supporting building blocks
Exclude tie device for leveling subfloor
Easily replace wooden and weakened floors with concrete
Cover rooms of complex shape with bay windows and ledges
Carry out installation in hard-to-reach places , including in existing premises
Reduce cost by 30-40% building floors
Ensure bearing capacity up to 1000 kg/m2
To ensure high performance of monolithic floors of buildings according to thermal protection and sound insulation
Refine floor structures at the construction site: cut, shorten, give the necessary shape
Use voids in blocks for laying communications
Use beams for the construction of powerful load-bearing jumpers
Deliver to the construction site up to 250 sq.m. SMP by one machine

, sand concrete, porous ceramic blocks. The photo shows an example of using ceramic porous blocks for floors. Sometimes this design is called brick floors. Here you can on the use of such overlaps. Brick flooring is quite common in Europe, but has never been used in Russia.

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The use of SMP allows you to get quality foundation gender. But such a technological operation imposes increased requirements on the qualifications of workers. Concreting in this case is carried out in two stages. At the first stage, the bulk of the bonding concrete is poured. After 3-4 hours, a concrete mixture is added to the partially set concrete to form a leveling screed.

Ceilings and floors are two interrelated structural elements of a building. The quality of the floor directly depends on the quality of the surface of the floors.

SMP concrete beams are well combined with load-bearing metal structures. Metal beam slabs are converted in this case to beamless concrete slabs. At the same time, the total thickness of the structure is more than halved. The latter is very important for buildings with low ceilings. This design serves as a good alternative to structures based on corrugated board.

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I-beams ceilings are well combined with beams of MARKO prefabricated-monolithic ceilings. The garage floor (ground floor) will become the floor of the spare parts warehouse. SMP MARKO provide high performance in terms of sound insulation through the use of polystyrene concrete blocks of low density, which absorb sound well.

Sturdy, lightweight, easy to install prefabricated monolithic ceilings have been used in many countries of the world for more than half a century. Now these progressive designs are produced by the construction company COLUMB in the Moscow region and can be used for your home, garage, bath. Traditional hollow core slabs or a heavy and expensive monolith can always be replaced by an SMP. The strength and bearing capacity of SMP MARKO is higher than that of standard structures, and the weight is much lower. This makes it possible to use MARCO SMP in every country house no limits.

Along with the SMP system monolithic construction MARCO contains fixed formwork blocks for walls. Sophisticated technical solutions allow customers to receive a complete set of structures for building a house in the construction company COLUMBS.

Marian Wojciech Szymański, Consultant, Structural Elements Factory (ZEK; Warsaw and Bochnia, Poland) from Partner Ost-West (Lodz, Poland). “It is interesting that the real bearing capacity, deflections and crack opening in the case of this product turned out to be even 20% better than the calculated ones. The task of reducing the weight and increasing the insulating characteristics of floors with fixed formwork slabs was solved through the use of……”. This is an extract from the materials of the seminar on the use of the TERIVA SMP. This is an extract from the materials of the seminar on the use of the TERIVA SMP, held in Minsk on March 22, 2006, within the framework of the 9th International Specialized Exhibition "StroyExpo 2006".Do you have a question?... Ask!

In this article we will talk about what are the methods of erecting a monolithic floor, and you will also learn about the advantages and disadvantages of these methods. The article will talk about the basic requirements for the thickness and reinforcement of reinforced concrete floor elements.

Reinforced concrete is an almost eternal material. Many structural elements are created from it - beams, walls, lintels. One of the most difficult, at first glance, products is overlapping. However, the complexity of the construction is fully offset by the operational properties of the finished product.

Advantages of a monolithic floor:

The highest load-bearing capacity of known materials.
The most durable of widely available materials.
Relatively cheap raw material (for concrete).
To perform the work, high qualification of the entire team is not required (1-2 leading specialists are enough).
Combined functions: the base of the floor of the second floor, the armored belt, the connection of all walls to each other.
A properly arranged monolithic structure eliminates the appearance of deformation defects (“steps”, distortions, cracks).

Disadvantages of concrete floors:

Labor intensity of construction. The work is connected with the installation of horizontal formwork of high strength and rigidity.
Accompanying material is involved, which after concreting may become unusable - plywood, flanging board, racks (wooden).
The heavy weight of the structure requires powerful walls and foundations.
High thermal conductivity of concrete - all areas open from the outside must be insulated.
Concrete floor only possible on stone walls.

Reinforced concrete floors are suitable for capital buildings designed for long term services, as well as for premises in which a significant static and dynamic load is provided - workshops, hotels, hostels (with partitions made of stone material).

In private construction, monolithic floor slabs are usually arranged along brick walls, since concrete walls are much more difficult to erect than brick ones.

The thickness of the monolithic slab

Due to the big specific gravity concrete (2400 kg / m 3), products from it are heavy. The mass of the product can be reduced by reducing the part of the concrete in the structure, that is, simply making it thinner. Rigidity is compensated by reinforcement. Sufficient thickness of reinforced concrete elements:

load-bearing walls - 160 mm
floors - 200 mm
partitions - 100 mm

The thickness of these elements will be considered sufficient only if the rules of reinforcement are observed. Calculations and many years of practice have shown that there is an optimal balance of mass, volume, section and bearing capacity of reinforced concrete elements. Read about this below in the section "Reinforcement of floors". Sufficient thickness brick wall- 380 mm (1.5 bricks).

Floor formwork

Like any reinforced concrete element, the ceiling requires the installation of a form for concrete - formwork. Since the ceiling has a significant area and is at a height, the formwork for it has the form of a table: a solid plane that fills the space between the bearing walls (and columns) on a spatially rigid frame of racks and slopes. Formwork happens three types, but one requirement is invariable for any of them - a reliable foundation.

Inventory formwork

Factory kit, which includes:

Racks - screw retractable jacks, up to 4 m long.
Equipment for racks - “tripods” at the bottom for the stability of a free-standing jack and a “crown” at the top for landing table beams.
Wooden beams - factory glued products of an I-profile 200 mm high and up to 4.2 m long.
Laminated plywood - sheets of plywood 18-24 mm thick, 1220x2440 mm in size, covered with a stable film, designed to create a floor plane. The coating withstands up to 40 concreting cycles.

Such a set is professional - high-rise buildings are built with inventory formwork residential buildings. It is reliable, comfortable and designed for continuous use. The purchase of a set for the installation of one floor will not justify itself - all steel products are not cheap. Formwork rental can be a solution. The company's specialists will calculate required amount each of the elements for your object.

The undoubted advantages of this approach are the speed of formwork installation and ease of use, as well as the quality of the plane. The disadvantages include the risk of delaying the lease term.

Homemade formwork

All elements of the "table" for overlapping can be made independently from wood and some metal parts.

This method is used when the main elements - racks, beams and plane material (plywood or board) are available. This is the main advantage of the method - the use of improvised material. Obvious disadvantages:

Labor-intensive construction requiring advanced carpenter skills.
Large waste of material - up to 20% will become unusable.
Problematic height adjustment (“horizontal” installation).

Combined method

It provides for the partial use of inventory formwork elements and lumber.

In this case, you can use the factory racks with tripods and crowns, and make the beams and formwork flooring from the board. Or rent laminated plywood, and assemble the frame of the "table" from the wood at hand. There can be many combinations.

Floor reinforcement

For device reinforcing cage hanging reinforced concrete floor with a thickness of 200 mm, a mirror mesh of reinforcement A3 Ø 16 mm with a cell of 150-180 mm is used. When using concrete prepared on site, we recommend reinforcing the frame by using a smaller rod spacing of 150 mm. If the concrete is factory, a step of up to 200 mm is allowed. In places of support and junction of elements (support on a wall, column, capital), we recommend making reinforcements - adding rods.

Floor concreting

There are concreting rules that must be observed unquestioningly so as not to subject the structure to destruction in the future:

The laying of concrete in the ceiling must be done in one go. If the concrete is not placed for a long period of time, the laid concrete may seize and the new concrete will not be able to mix with it. The result is a boundary along which a crack can go.
When concreting in a cool period (0...+5 °C), use special anti-frost additives. Read more about winter concreting in this article.
Be sure to use vibrators - deep or surface. Without vibration, concrete has 40-50% of the design strength. You will find more information about concreting in our article.
The ceiling formwork is dismantled no earlier than 28 days after concrete is laid.

The ceilings are solid reinforced concrete structures. Their use is relevant for increased weight loads, especially in high-rise buildings. In private construction, their main advantages include the ability to reduce installation costs by independently performing individual or all stages of work with minimal involvement of special equipment. The technology is considered time-consuming; to eliminate errors, the calculation of the slab should be entrusted to specialists. The parameters obtained must be taken into account when preparing the main project of the house.

Conditionally, everything is divided into prefabricated (solid or hollow, manufactured at the factory), often ribbed (cellular type with sections of lightweight material or empty blocks) and monolithic. The latter are valued primarily for the absence of seams, this option is selected when concreting multi-storey buildings, pouring floors or delimiting floors in individual buildings. Depending on the design and installation method, they are divided into: beam, beamless (the most popular variety in the construction of private houses with a smooth surface), with fixed formwork(simultaneously performs the role of a heat-insulating layer) and laid on a steel deck. The latter are valued for reducing labor intensity and the possibility of reducing thickness and weight.

Features and benefits of a monolithic floor

The pluses include:

1. Strength and solidity (lack of seams), and, as a result, ensuring a uniform load on the foundation and load-bearing walls.

2. Possibility of leaning on columns. This gives more freedom in the planning process compared to the option of laying prefabricated floor slabs from prefabricated standard size elements.

3. Safe arrangement of the balcony without the need for additional supports due to the solidity of the main horizontal structure.

Calculation of the slab, drawing up a reinforcement scheme

Ideally, the design is entrusted to specialists, they will help you choose the option with correctly distributed loads, which is optimal in terms of “reliability-cost of building materials”. The initial data for self-calculation are the dimensions of the floor with the obligatory consideration of the width of the supporting platforms. The thickness of the monolith is selected based on the maximum value of the longitudinal span (the ratio recommended for beamless structures is 1:30, but not less than 15 cm). For floors within 6 m, the minimum is 20 cm, over 6, options are considered with their reinforcement with stiffeners. In varieties of the beam type, the step of the supports is taken into account (respectively, the minimum height is found by dividing it by 30).

The calculation of the slab begins with determining its own weight: the average (2500 kg / m3) is multiplied by the thickness of the floor. The rate of live load (weight of furniture, equipment and people) for residential buildings is 150 kg / m2, taking into account 30% of the reserve, it is increased to 195-200. The total, maximum possible load is obtained by adding these values.

To check the section of the reinforcement, the maximum bending moment is calculated, the formula depends on the way the weight is distributed. For a standard beamless floor supported by two load-bearing walls М max = (q l2)/ 8, where q is the total load, kg/cm2, l2 is the span width. This formula is the simplest, in the absence of reinforcement in the zones of maximum compression of concrete or uneven distribution of weight, it becomes more complicated.

To check the cross section of the reinforcement, a coefficient is calculated that takes into account the design resistance of building materials (reference values depend on the selected mortar strength class and steel grade). The obtained value corresponds to the minimum allowable metal area in the cross section of the plate. It is compared with the preliminary one; if it is exceeded, the circuit needs to be strengthened (reducing the cell pitch or using rods with a larger diameter).

Due to the complexity of the calculation, specialists are usually trusted; when passing it, a chess pattern is selected from two grids (lower and upper) with a cell pitch of 20 × 20 cm and a rod thickness of 10-14 mm (hot-rolled steel). Both reinforcement is provided in the center of the monolithic slab, areas with increased loads and places of contact with supports, as well as a margin for overlapping walls (depending on the strength of building materials - from 150 mm for brick to 250 for cellular concrete). Longitudinal and transverse rods, if possible, are laid inseparably, if this condition is violated, they overlap - at least 40 cm.

The main stages of installation

Laying begins with the calculation and purchase of building materials (ideally, project data is used). Formwork structures are being prepared: panels made of thick moisture resistant plywood, metal or plastic, beams and telescopic supports (1 piece/m2), equipment for preparing, supplying and compacting concrete, a tool for bending reinforcement and special stands. If necessary, an armored belt is laid along the perimeter of the load-bearing walls, such a need arises when erecting ceilings in a house made of aerated concrete.

The main steps include:

Assembly and installation of formwork.
Placement of the armored carcass.
Filling a monolithic slab with concrete, compaction and leveling.
Moisture maintenance of the solution, covering, dismantling of the formwork after 28 days.

1. Requirements for supports and shields.

Installation involves pouring concrete into a sealed horizontal formwork, preference is given to special collapsible structures. In principle, it is easy to make shields yourself from plywood with a thickness of at least 20 mm (it is better not to use boards due to difficulties in fitting). A prerequisite is the installation of telescopic metal racks(during the construction of the floor of the first floor of the house, they are replaced by stationary supports). In their absence, replacement with logs with a diameter of at least 8 cm is allowed, but one should be prepared for problems when adjusting the level.

To support the shields, a crossbar is laid - a longitudinal beam with a cross section of at least 10 × 10 cm, if necessary, the formwork is reinforced with transverse elements (this situation most often occurs when working with homemade products). The shields are laid without gaps, the edges tightly rest against the wall. During installation vertical structures the value of approach to carrier systems is taken into account. To eliminate the risk of leakage, the bottom is covered with a film, sealed factory reusable varieties are lubricated to facilitate the removal process. The stage ends with a level check, deviations are not allowed.

2. What should be taken into account when reinforcing?

Reinforcement with metal is the main requirement of the technology. The distance from the edge of the concrete to the metal is at least 25 mm. The joints are tied with wire with a cross section of 1.2-1.5 mm, welding is not allowed. For setting up the grids, pre-prepared clamps are used: made of steel with a thickness of at least 10 mm, with an interval of up to 1 m, similar elements are placed at the ends. Reinforcement of a monolithic reinforced concrete floor is completed with the laying of connectors that ensure uniform load perception on the entire system - after 40 cm near the walls, after 70 from it, with a subsequent step of 20.

3. Nuances of concreting.

The main requirement of the technology is the continuity of the process; ideally, the solution is ordered at factories and poured using the appropriate equipment. The recommended thickness of the concrete layer is 20 cm, which in most cases coincides with the height of the floor itself. The minimum grade is M200, in order to enhance the thermal insulation properties and lighten the weight, part of the coarse-grained high-strength filler can be replaced with expanded clay, but this method requires approval by specialists (strength testing).

Holes for the supply of communications and ventilation ducts are laid before the start of pouring, drilling of a frozen monolithic slab is a violation. The stage ends with the obligatory compaction of concrete using internal vibrators. The rules for caring for the surface are generally standard, but it is impossible to water the structure abundantly with water, unlike the foundation or vertical walls it wets more gently.

Rates

The cost of filling when contacting professional firms varies from 4,000 to 9,000 rubles / m3 (subject to the use of the customer's formwork). The total cost depends on the chosen reinforcement scheme, the height of the future slab (from the ground level or from the mark of the previous horizontal support) and its thickness, the method of placement (on columns or load-bearing walls), and the total amount of work. The list of services of construction companies includes installation and dismantling formwork structures, assembly of the reinforcement cage according to a project prepared in advance (paid separately), continuous concreting and care of the laid mixture: watering, covering, if necessary - warming up. The advantage of turning to professionals is the mandatory quality control carried out at the end of curing.

The advantages of laying flooring with your own hands include a reduction in the cost of paying for work - up to 30% at least. For pouring, simple building materials are used - concrete and reinforcement, saving on them is unacceptable. The volume of the solution is calculated based on the thickness and area of the slab, the length and weight of the metal - according to the reinforcement scheme drawn up in advance. Renting formwork structures is expensive: the minimum price per m2 is 400 rubles per month (you can’t rent it earlier).

Additional costs when doing do-it-yourself work include the need for special equipment and containers for raising the solution up (bucket shoes and a crane or concrete pump). This is not a problem when arranging solid floors on basement floors at home, but in other cases, you cannot do without the appropriate equipment. This is due to the main requirement of the technology - a continuous process of concreting, monolithic ceilings with individual patches, frozen on different days, are inferior in quality to those poured at a time. Minimum costs when performing all stages, they independently amount to 3200 rubles per 1 m2 with a plate thickness of 20 cm.

Ceilings from prefabricated reinforced concrete (floor slabs).

	To date, reinforced concrete slabs are the most commonly used type of interfloor ceilings. According to their bearing capacity, they are divided into three main groups: Bearing capacity: 400 kg/m2 or 4 load Bearing capacity: 600 kg/m2 or 6 load Bearing capacity: 800 kg/m2 or 8 load with a capacity of 800 kg / m2, with very rare exceptions, you can find 600 kg / m2 and not find 400 kg / m2 at all. And along with this, there is SNIP 2.01.07-85 "Loads and Impacts", which determines the necessary and sufficient bearing capacity of floors, depending on the type of premises. In accordance with SNIP (clause 3.11 table 3), the bearing capacity of the floors of an apartment in a residential building is 150 kg / m2, and the largest value is 500 kg / m2 and is assigned to book depositories, archives, stages of entertainment enterprises, stands for standing spectators, as well as for premises for raising livestock. Now let's figure out what the bearing capacity of 800 kg / m2 means in relation to the house in question. Let's take for example the most loaded room, namely the Kitchen-Living Room (with an area of 27.3 m2). When using reinforced concrete slabs, the bearing capacity of this room will be: 27.3 m2 * 800 kg / m2 \u003d 21,840 kg if we subtract the weight of furniture and interior elements from this value (maximum 500 kg), then we get a residual bearing capacity of 21,340 kg. Now let's determine how many people can withstand such an overlap with an average person weighing 100 kg. Number of people = 21,340 kg / 100 kg = 213 people! It is clear that such a number of people in this room is simply not fit. If we talk about the possibility of this room from the point of view of the people present, then this is no more than 20 people at the "peak" load. In other words, you get a safety factor of 10! In civil engineering, the safety factor does not exceed 0.5, and for military designers / builders it does not exceed 5!

	In fact, using reinforced concrete slabs, you get a high bearing capacity, the value of which exceeds the standard by 5 times! At the same time, under no circumstances will you use a high bearing capacity "for its intended purpose", since there is not enough space in the room to place a significant load on it. From point of view fire safety, sound insulation, thermal insulation, the option of reinforced concrete slabs does not stand out in any way relative to other types of floors. It is on the basis of the foregoing that the standard for bearing capacity for apartments in residential buildings is prescribed at the level of 150 kg / m2. If we carry out similar calculations, but in accordance with normative value, then we get: 27.3 m2 * 150 kg / m2 = 4,095 kg if we subtract the weight of furniture and interior elements from this value (maximum 500 kg), then we get a residual bearing capacity of 3,595 kg. Now let's determine how many people can withstand such an overlap with an average person weighing 100 kg. Number of people = 3,595 kg / 100 kg = 36 people! It is clear that such a number of people in this room is simply not fit. If we talk about the possibility of this room from the point of view of the people present, then this is no more than 20 people at the "peak" load. In other words, you get a safety factor of 1.8! Let me remind you that in civil engineering the safety factor does not exceed 0.5, and for military designers / builders it does not exceed 5! That is why the standard of 150 kg / m2 is sufficient for the normal operation of residential premises! P.S. When designing lightweight economical floors from LVL beams, we lay down the bearing capacity from 180 kg/m2, thereby slightly exceeding the standard and getting a safety factor of at least 2!

Calculation of costs for the installation of a precast concrete floor over a cold underground using floor slabs of the PNO series. The calculation also includes materials for thermal insulation and leveling the base for finishing the floor.

1. Plate PNO 1m2 / 1125 rubles

2. Mortar for joints M200 0.126tn / 315 rubles

3. Leveling screed

M200 thickness 50mm 0.100 tons / 250 rubles

4. Extruded foam

5. Vapor barrier film 1m2 / 22 rubles

6. Reinforcing mesh 200x200x5mm 1m2 / 60 rubles

7. Leveling screed

M300 thickness 50mm 0.100tn / 260 rubles

8. Finishing screed 5mm 0.0075tn / 203 rubles

Total, the cost of materials for 1m2 = 2,969 rubles

1. Installation of plates PNO 1m2 / 600 rubles

2. Concreting of joints of slabs 1pc / 288 rubles

3. Performing a leveling screed

M200 thickness 50mm 1m2 / 400 rubles

Total, the cost of work for 1m2 = 2,488 rubles

Total materials and work for the installation of prefabricated reinforced concrete floors: 5 407-00 rub / m2.

Ceilings from monolithic reinforced concrete.

Scope: Interfloor overlappings in construction.

We consider the cost of erecting 1m2 of the floor structure.

Calculation of expenses for the device of overlapping from monolithic concrete above the cold underground. Except material load-bearing structure the calculation also includes materials for thermal insulation and leveling the base for finishing the floor.

1. Ready-mixed concrete B 25 1m2 / 880 rubles

2. Fittings (12mm and 6mm) 0.02tn / 500 rubles

3. Extruded foam

listirol, thickness 150mm 0.150m3 / 734 rubles

4. Vapor barrier film 1m2 / 22 rubles

5. Reinforcing mesh 200x200x5mm 1m2 / 60 rubles

6. Leveling screed M300

thickness 50mm 0.100tn / 260 rubles

7. Finishing screed 5mm 0.0075tn / 203 rubles

8. Formwork rental for a month 1 unit / 400 rubles

Total, the cost of materials for 1m2 = 3,059 rubles

1. Installation / dismantling of formwork 1m2 / 600 rubles

2. Installation of arm. frame 0.02 tons / 200 rubles

3. Concrete placement taking into account

cost of a concrete pump 1m2 / 580 rubles

4. Laying extruded foam

polystyrene, thickness 150mm 1m2 / 100 rubles

5. Laying vapor barrier films 1m2 / 100 rubles

6. Installation reinforcing mesh 1m2 / 150 rubles

7. Performing a leveling screed

M300 thickness 50mm 1m2 / 600 rubles

8. Finishing screed 1m2 / 200 rubles

Total, the cost of work for 1m2 = 2,530 rubles

Total materials and work for the installation of a monolithic ceiling: 5 589-00 rub / m2.

Ceilings on wooden beams.

Below is a cost estimate for a ceiling device using a classic edged
lumber - wooden beam. The span between the supports is 4.7 meters. In costing
also included are materials for thermal insulation and leveling the base for finishing the floor.
wooden elements roof structure made of coniferous wood with moisture
no more than 20%, pre-treated protective compounds in accordance with the requirements
SNiP 2.03.11-85 "Protection building structures from corrosion", chapter 3 " wooden structures",
as well as the requirements of SNiP 2.01.02-85 “Fire safety standards”, clause 1.8.
For a span of 4.7 meters, with a center distance of 500mm when using a wooden beam
200 * 100 mm, the following overlap indicators are provided:

Bearing capacity 300 kg/m2,

Weight of floor structures 140 kg/m2

total "free" bearing capacity of the floor 160 kg/m2 (according to SNiP ”Loads and impacts”
for residential buildings the standard is 150 kg/m2). In the calculation below, the center distance
between the beams is assumed to be 625 mm to ensure waste-free laying of the DSP slab, 1250 mm wide.
lumber natural humidity deformed in the process of shrinkage and loss of moisture, while
the height difference of the floors reaches 10 mm / 1 linear meter, therefore, the calculation provides for
leveling screed 50 mm thick.

We consider the cost of erecting 1m2 of the floor structure.

Calculation of costs for the installation of a wooden beam ceiling over a cold underground. In addition to the material of the supporting structure, the calculation also includes materials for thermal insulation and leveling the base for finishing the floor.

1. Lumber 1.97 m3 / 15760 rubles

2. Fasteners 1pc / 3600 rubles

3. Fire bioprotection 1pc / 7800 rubles

4. TsSP 20mm 39m2 / 13380 rubles

5. TsSP 10mm 39m2 / 8350 rubles

6. URSA PureOne 200mm 7.8m3 / 11270 rubles

7. Vapor barrier and adhesive tape 1pc / 2000 rubles

8. Leveling screed M300

thickness 50mm 3.9 tons / 10140 rubles

9. Finishing screed 5mm 0.29tn / 7920 rubles

Total cost of materials for 39.25 m 2 = 80,220 rubles

1. Installation of the frame of floors 350 rubles / 13650 rubles

2. Fire bioprotection 200 rubles / 7800 rubles

3. DSP installation 10mm 200 rub / 7800 rub

4. Installation of DSP 20mm 200 rubles / 7800 rubles

5. Laying PureOne insulation 200 rubles / 7800 rubles

6. Laying vapor barrier. films 100 rubles / 3900 rubles

7. Performing a leveling screed

M300 thickness 50mm 600 rub / 23400 rub

8. Performing the finishing screed 200 rubles / 7800 rubles

Total cost of workfor 39.25 m 2 = 79,950 rubles

Total materials and work for the installation of floors on wooden beams: 4 081-00 rub / m2.

Ceilings on beams from LVL beams.

Scope: Interfloor overlappings in construction, frame housing construction, rafter system.

Below is a cost estimate for a floor installation using LVL beams. The span between the supports is 4.7 meters. The calculation also includes materials for thermal insulation and leveling the base for finishing the floor.
For a span of 4.7 meters, with a center distance of 625mm when using a beam LVL beam 240*45 The following coverage indicators are provided:

Load bearing capacity 300 kg/m2

Weight of floor structures 55 kg/m2,

total "free" bearing capacity of the floor 245 kg/m2 (according to SNiP "Loads and Impacts" for residential buildings standard 150 kg/m2). In the calculation presented below, the center-to-center distance between the beams is assumed to be 625 mm to ensure waste-free laying of the DSP slab, 1,250 mm wide

To simplify the calculations, the following costs are given for a room of 8.3x4.7 m.

We consider the cost of erecting 1m2 of the floor structure.

Calculation of costs for the installation of a ceiling from LVL beams over a cold underground. In addition to the material of the supporting structure, the calculation also includes materials for thermal insulation and leveling the base for finishing the floor.

Total materials and work for the installation of flooring on beams from LVL beams: 2 942-00 rub / m 2.

What's in the dry matter?

The cost of erecting a floor structure for a house according to project 83-08.

Basement floor area 124 m 2

Option 1. Precast concrete floors = 5,407 rubles / m 2 * 124m 2 = 670 468 rub

Option 2. Ceilings made of monolithic reinforced concrete = 5,589 rubles / m 2 * 124m 2 = RUB 693,036

Option 3. Floors on wooden beams = 4,081 rubles / m 2 * 124m 2 = RUB 506,044

Option 4. Overlapping on beams from LVL timber \u003d 2,942 rubles / m 2 * 124m 2 \u003d 364 808 rubles!

It is worth noting:

glued beams do not create squeaks
in our projects, the ends of the beams are not walled into the body of the wall, the beams are fastened on brackets, even capillary suction of moisture from the wall structure is excluded, the floor materials always remain dry, as a result - the service life of the ceiling is equal to the service life of a stone house
the space between the beams is completely filled with mineral wool non-combustible material, the subfloor, as well as the filing of the beams, is carried out using materials that do not support combustion, DSP, fire-resistant drywall, this design has high fire resistance, because. around the beam there is no free air necessary for the combustion process.

The statement that wooden floors have the lowest cost,is a delusion.

To date, LVL timber has the best price / quality ratio. It is this material that is preferred in many private and public facilities, for example, the balconies of the Mariinsky Theater or the supporting frame of the dome of the new Oslo airport are made of LVL timber.

Additional benefits of choosing modern building technologies.

Application in construction of modern materials and solutions, such as LVL beams for floors and truss system or porous ceramic blocks Caiman30 for external load-bearing walls, allows you to save money not only within the current technical solution, and without worsening the necessary and sufficient consumer properties and characteristics, but also significantly reduce costs at other stages, as well as get more high quality construction.

An example is the situation when the replacement of reinforced concrete floors with floors using LVL timber and 44 ordinary ceramic blocks for heat-efficient ceramic blocks Cayman30, for external and internal walls, significantly reduces the weight of the house.

Difference within house project 83-08 is:

by floors 147.8 tons
along the walls 37.9 tons,

total 185.7 tons or 30% reduction in the load on the base), which allows at the foundation stage to be limited to an economical and sufficient design option, namely, a monolithic reinforced concrete pile-grillage foundation, the construction costs of which are 4-5 times lower than for the construction of a monolithic strip foundation!

Replacing a monolithic strip foundation with a monolithic pile-grillage foundation will also lead to an overall reduction in the load on the foundation, by about another 99 tons.

The total total weight reduction of building structures, and as a result of pressure on the base, is 284.7 tons.