The MARCO-STANDARD slab became the first Russian prefabricated monolithic slab that found wide application in housing, civil and industrial construction.
Progressive prefabricated monolithic technology for constructing reinforced concrete interfloor light floors has been used in Europe for more than 70 years. Known in Russia prefabricated monolithic floors YTONG, Polish floors TERIVA (TERIVA), Belarusian ceilings DAH . Overlapping MARCO retained all the best qualities of European floors and added something new -a square meter of Russian flooring is 80-100 kg lighter than European .
Scheme of a MARCO-STANDARD beam with additional longitudinal reinforcement
Dimensions cross section concrete beam element 40x120 mm, concrete strength class not lower than B20. For increase bearing capacity The concrete element can be reinforced with additional longitudinal reinforcement with a diameter of 6 to 16 mm. All beam reinforcement is rolled welded reinforcement of periodic profiles 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 slabs was confirmed by another patent. In the design of these floors, the base of the beam is not a concrete block, 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 labor intensity of installing floors, to cover spans of up to 12 meters, to form balconies and consoles using floors, and to create openings of various configurations in a monolithic slab. Working with profile beams is in many ways similar to working with a profile for drywall. Buyers of floors quickly appreciated the benefits of the new floors.
In October 2013 we received a patent on a beam, which allows you to use any building blocks in the floors. 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 erected and order only beams from our company. The new ceiling was named. The name once again emphasizes the versatility of the proposed design. Building blocks available in any region of Russia. This means. that today builders anywhere in Russia can install MARCO floors.
Floor beams in production. The photo clearly shows the additional reinforcement of the beams.
The production of beams is carried out 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 act as permanent formwork and take on the loads that arise during concreting.
Technical documentation for blocks and floor beams has been agreed with the Research, Design and Technological Institute of Concrete and Reinforced Concrete NIIZhB and registered GOSTSTANDARD.
Based on 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 received for MARCO polystyrene concrete.
A high-performance vibration stand is used to produce floor blocks. The productivity of the vibration stand is 3000 blocks per shift. This allows you to complete blocks of 350 m 2 of floors.
MARCO-STANDARD technology provides four floor thicknesses: 200, 250, 300 and 350 mm.
Floor plan MARCO-STANDARD 200 mm thick
Scheme of the thinnest ceiling of the MARCO system SMP-200 presented in the figure.
Scheme of a MARCO floor with a thickness of 300 mm, in which an additional slab with a thickness of 50 mm is used.
The Russian MARCO system for thicknesses greater than 250 mm uses additional foam boards.
The slabs are glued to the upper surface of the blocks with any cement-containing tile adhesive. This solution allows you to use a single nomenclature of blocks.
MARCO flooring 350 mm thick with additional insulation
Floor installation diagram without a separate monolithic belt
Installation of prefabricated monolithic ceiling MARCO-STANDARD . The beams are hung above the Itong aerated concrete wall with a gap of 40-50 mm. This made it possible to form a monolithic belt simultaneously with concreting the floor
Usage prefabricated monolithic floors MARCO allows abandon the mandatory installation of a separate monolithic belt (seismic belt, armored belt) on walls made of weak-bearing materials (aerated concrete, foam concrete, MARCO polystyrene concrete, expanded clay concrete, etc.). Using simple technological techniques, a monolithic belt is formed simultaneously with concreting the floor slab.
To do this, the 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 be formed on the wall. This method of installing permanent formwork for the floor and seismic belt significantly reduces the cost of construction and shortens the time.
The photograph clearly shows how this scheme is implemented on a 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 the event of uneven shrinkage of the foundation.
Photo
Photo
| Overlap index Tia | Thickness mm | Own ny weight kg | Index block | Thickness additional Noah slabs mm | Covered spans and permissible payloads | |||||||
| 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 load-bearing capacity is an undoubted competitive advantage SMP MARCO.
There are no ceilings lighter than MARCO in Russia.
The cross-section of the concrete element obtained as a result of concreting is similar in design to a factory-made ribbed slab. Each rib consists of a beam and a concrete core. Cross-sectional shapeconcrete corepresented in the diagram.
Low block weight allowed to increase the vehicle loading rate. A standard 12 m long body holds 220-250 sq. m of floors. When transporting over a distance of up to 1000 km, the cost of delivery of one square meter of structures does not exceed 200 rubles.
Photo
Photo
Photo
To finish SMP ceilings, you can use plasterboard on metal or wooden frame, plastic panels, plaster, dropped ceilings like Amstrong, wooden lining and other finishing materials.
Prefabricated monolithic floors are successfully used for the reconstruction of industrial buildings.
Specialists construction company Columbus will develop for you design documentation for prefabricated monolithic floors, will offer a rational plan for the floor, make a drawing of the floor, show a photo of the floor, prepare recommendations for installation, deliver the SMP to construction site, if necessary, they will carry out installation.
Our experience shows - in some cases, only SMP allows for reinforcement of floors.
Photo
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 with wooden beams on SMP. In this case, the task of strengthening the structure (increasing the load-bearing capacity) is often set. As a rule, the thickness of the monolithic materials obtained as a result of reconstruction interfloor ceilings less than the thickness of the original wooden floor. In this case, the monolithic ceiling is connected to load-bearing walls and strengthens them.
Photo
If necessary beams and blocks can be easily modified directly on the construction site. This feature is often used to install bay windows and rooms with complex wall configurations.
Production allows for precision beam manufacturing within one centimeter, but low accuracy of wall construction often leads to the need to modify the beams at the construction site.
Photo
Photo
Photo
In the Foto ground floor Igor Borisovich Chubais, which the Columbus construction company built in 2006. The house has two emergency stations between the floors in which they were used beams up to 8 meters long.
AT THE LAYING OF THE HOUSE THE FOUNDATION WAS CONSECCATED
, sand concrete, ceramic porous blocks. The photograph shows an example of using ceramic porous blocks for flooring. Sometimes this design is called brick floors. Here you can learn how to use such floors. Brick floor It is quite common in Europe, but has never been used in Russia.
Photo
Using SMP allows you to get quality foundation floor. But such a technological operation places increased demands on the qualifications of workers. In this case, concreting is carried out in two stages. At the first stage, the bulk of the fastening concrete is poured. After 3-4 hours, concrete mixture is poured onto the partially set concrete to form a leveling screed.
Floors and floors are two interconnected elements of a building's structure. The quality of the floor directly depends on the quality of the surface of the floors.
SMP concrete beams combine well with load-bearing metal structures. Beam floors made of metal are converted in this case into beamless floors made of concrete. At the same time, the total thickness of the structure is reduced by more than half. The latter is very important for buildings with low ceilings. This design serves as a good alternative to structures based on corrugated sheets.
Photo
I-beams floors are well combined with beams of prefabricated monolithic floors MARCO. The garage floor (ground floor) will become the floor of the spare parts warehouse. SMP MARCO provide high levels of sound insulation through the use of low-density polystyrene concrete blocks, which absorb sound well.
Durable, lightweight, easy-to-install prefabricated monolithic floors have been used in many countries around the world for more than half a century. Now these progressive designs are produced by the COLUMB construction company in the Moscow region and can be used for your home, garage, or bathhouse. Traditional hollow core slabs or a heavy and expensive monolith can always be replaced with SMP. The strength and load-bearing capacity of SMP MARCO is higher than that of standard structures, and the weight is significantly lower. This allows the use of SMP MARCO in every country house no limits.
Along with the SMP system monolithic construction MARCO contains permanent formwork blocks for walls Well-thought-out technical solutions allow customers to receive a complete set of structures for building a house from the COLUMB construction company.
Marian Wojciech Szymański, consultant to the company "Plant of Building Elements" (ZEK; Warsaw and Bochnia, Poland) from the bureau "Partner Ost-West" (Lodz, Poland). “It is interesting that the actual load-bearing capacity, deflections and crack opening in the case of this product turned out to be even 20% better than the calculated ones. The problem of reducing weight and increasing the insulating characteristics of floors with permanent formwork slabs was solved through the use of......". This is an extract from the materials of the seminar on the use of TERIVA SMP. This is an extract from the materials of the seminar on the use of TERIVA SMP, held in Minsk on March 22, 2006 as part of the 9th International specialized exhibition "Stroyeskpo 2006".Do you have a question?... Ask!
When building a private house, it is important to choose the right Constructive decisions its elements. One of the most important structures can be called the ceiling. Properly selected thickness of the reinforced concrete floor slab in the house between floors will ensure its reliability and safety.
Monolithic slabs are suitable for use in massive buildings made of stone or brick. IN brick house such an overlap creates a disk that gives the building additional rigidity. When laying interfloor reinforced concrete floors, it is important to choose the type of its manufacture:
Both of these methods are common today, but gradually the first one is replacing the second one. The main disadvantages of a monolithic floor are the cost of formwork and the need to wait for the concrete to harden. The advantages include:
The advantages of prefabricated technology include:
This method has slightly more disadvantages than the previous one:
Scheme of a prefabricated product The choice between technologies for constructing floors between floors depends on the preferences of the future owner of the house and economic considerations. If the distances between load-bearing walls are far from standard, you will need a large number of non-standard products, which will lead to higher construction costs. In this case, it is better to opt for the monolithic version.
It is necessary to know the thickness of the slab in order to calculate the total height of the ceiling and floor. This will be required when calculating the height of the floor, room and the entire building. The thickness of the overlap depends on the type of structure chosen. If you decide to use monolithic technology, it also depends on the loads from people, furniture, equipment and floor construction.
These elements are most often used in construction. PC slabs are round-hollow. They are laid between floors, both in private houses and in multi-storey buildings. PB slabs are enough new technology, which is gradually replacing the PC series. They can be produced in any length, regardless of the dimensions given in regulatory documents. They differ in the manufacturing method - the continuous molding method. They have some limitations and are not fully studied, but they are successfully used in both private and mass construction.
Design diagram measuring 220 mm The thickness of the plate is standard. Is 220 mm. To calculate the total height of the floor with the floor structure, you need to add to this value:
In total, the height of the concrete floor in a private house with a floor structure when using PB or PC series slabs is approximately 300 mm.
These elements are in most cases used as additional elements for the PB and PC series. The laying of such slabs between levels is carried out in those places where the distance between the walls does not allow the installation of large-sized products. They have small dimensions in plan, which allows them to cover small spans. The slabs are suitable for installation over corridors, bathrooms, utility rooms and storage rooms. Support can be done on all sides.
Reinforced concrete products for residential and public buildings Product thickness 80 or 120 mm. The total height of the reinforced concrete floor with floor elements is 150-200 mm depending on the type flooring.
When used, align with PC and PB products along the upper edge of the floor.
Irregularities are corrected using the ceiling structure.
A fairly common method for private housing construction. In this case, the profiled sheet serves as formwork and a load-bearing element of the monolithic slab. Main design elements:
Product design based on profiled sheets All thicknesses are selected depending on the payload. For a private house, you can give the average values of a monolithic slab between spaces located at different horizontal levels:
Supporting a profiled sheet can occur in two ways:
In the first case, the thickness takes into account the full height of the I-beam or channel, and in the second, the thickness of the reinforced concrete floor is significantly reduced. Minimum height given for light load.
By regulatory documents, the weight that falls on the floors in a private house is 150 kg per square meter.
When calculating, this value must be increased by a safety factor of 1.2. For more severe loads, reinforced corrugated sheets and a thicker concrete layer are used.
For a private home, you can use another technology for making a floor base. Ribbed reinforced concrete slab consists of long ribs spread along the long sides of the room and a thin layer of concrete between them. The space between the ribs is filled with insulation (expanded clay, mineral wool, expanded polystyrene and the like).
The thickness of the monolithic slab is calculated from the following values:
A ribbed ceiling, as well as a corrugated sheet, allows you to reduce concrete consumption while maintaining a sufficiently large thickness. Making ribs – difficult task. The use of corrugated sheets allows you to create a floor with a ribbed surface without unnecessary labor costs.
Proper selection and calculation of the thickness of the concrete slab will allow you to calculate the height of the premises, consumption concrete mixture and determine financial and labor costs at the design stage of the facility. In the case of prefabricated floors, the thickness for all elements is standard.
Floors made of precast reinforced concrete (floor slabs).
 |
Today, reinforced concrete slabs are the most commonly used type of interfloor slabs. According to their load-bearing capacity, they are divided into three main groups: Load-bearing capacity: 400 kg/m2 or 4 load Load-bearing capacity: 600 kg/m2 or 6 load Load-bearing capacity: 800 kg/m2 or 8 load Currently, slabs with load-bearing capacity are mainly produced capacity of 800 kg/m2, with very rare exceptions you can find 600 kg/m2 and not 400 kg/m2 at all. And at the same time, there is SNIP 2.01.07-85 “Loads and Impacts”, which determines the necessary and sufficient load-bearing capacity of floors depending on the type of premises. In accordance with SNIP (clause 3.11 table 3), the load-bearing capacity of the floors of an apartment in a residential building is 150 kg/m2, and the most great importance is 500 kg/m2 and is allocated for book depositories, archives, stages of entertainment enterprises, stands for standing spectators, as well as for premises for raising cattle. Now let's figure out what a load-bearing capacity of 800 kg/m2 means in relation to the house in question. Let's take as an example the most loaded room, namely the Kitchen-Living Room (with an area of 27.3 m2). When using reinforced concrete slabs, the load-bearing capacity of this room will be: 27.3 m2 * 800 kg/m2 = 21,840 kg, if we subtract the weight of furniture and interior elements from this value (maximum 500 kg), we will get a residual load-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 simply cannot fit in this room. 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 “peak” load. In other words, you will 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, by using reinforced concrete slabs, you get high load-bearing capacity, the value of which exceeds the standard by 5 times! In this case, under no circumstances will you use the high load-bearing capacity “for its intended purpose,” since there is not enough room area to place a significant load on it. From point of view fire safety, sound insulation, thermal insulation, the version of reinforced concrete slabs does not stand out in any way compared to other types of floors. It is based on the above that the load-bearing capacity standard for apartments in residential buildings is set at 150 kg/m2. If we carry out similar calculations, but in accordance with the standard value, 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), we get the residual load-bearing capacity 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 simply cannot fit in this room. 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 “peak” load. In other words, you will 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 normal operation of residential premises! P.S. When designing lightweight, economical LVL timber floors, we set a load-bearing capacity of 180 kg/m2, thereby slightly exceeding the standard and obtaining a safety factor of at least 2! |
 |
|
 |
Calculation of costs for installing precast reinforced concrete floors 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. PNO slab 1m2/ 1125 RUR 2. Mortar for joints M200 0.126tn / 315 rubles 3. Leveling screed M200 thickness 50mm 0.100tn / 250 rub. 4. Extruded foam 5. Vapor barrier film 1m2 / 22 rub. 6. Reinforcing mesh 200x200x5mm 1m2 / 60 rub. 7. Leveling screed M300 thickness 50mm 0.100tn / 260 rub. 8. Finishing screed 5mm 0.0075tn / 203 rub. Total cost of materials for 1m2 = 2,969 rubles |
1. Installation of PNO slabs 1m2 / 600 rubles 2. Concreting slab joints 1 piece / 288 RUR 3. Performing a leveling screed M200 thickness 50mm 1m2 / 400 RUR Total 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.
Floors made of monolithic reinforced concrete.
Scope of application: Interfloor ceilings in construction.
We calculate the costs of erecting 1 m2 of floor structure.
Calculation of costs for the installation of ceilings from monolithic concrete over the cold underground. In addition to the material of the supporting structure, the calculation also includes materials for thermal insulation and leveling of the base for finishing the floor.
|
1. Ready-mix concrete B 25 1m2/ 880 RUR 2. Reinforcement (12mm and 6mm) 0.02t / 500 rub. 3. Extruded foam listyrene, thickness 150mm 0.150m3 / 734 RUR 4. Vapor barrier film 1m2 / 22 rubles 5. Reinforcing mesh 200x200x5mm 1m2 / 60 rub. 6. Leveling screed M300 thickness 50mm 0.100tn / 260 rub. 7. Finishing screed 5mm 0.0075tn / 203 rub. 8. Rent of formwork for a month 1 unit / 400 rubles Total cost of materials for 1m2 = 3,059 rubles |
1. Installation / dismantling of formwork 1m2 / 600 rubles 2. Installation of arm. frame 0.02t / 200 rub 3. Laying concrete taking into account cost of a concrete pump 1m2 / 580 rubles 4. Laying extruded foam listyrene, thickness 150mm 1m2 / 100 RUR 5. Laying vapor barriers. films 1m2 / 100 RUR 6. Installation of reinforcing mesh 1m2 / 150 rubles 7. Performing a leveling screed M300 thickness 50mm 1m2 / 600 RUR 8. Performing finishing screed 1m2 / 200 rubles Total cost of work for 1m2 = 2,530 rubles |
Total materials and work for installing a monolithic floor: 5,589-00 rub/m2.
Floors on wooden beams.
 |
 |
| Below is a calculation of the costs of installing a floor using classic edged lumber - wooden beam. The span between the supports is considered to be 4.7 meters. To costing materials for thermal insulation and leveling the base for finishing the floor are also included. Wooden elements truss structure made of wood coniferous species with humidity no more than 20%, pre-treated protective compounds according to requirements SNiP 2.03.11-85 "Protection of 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-to-center distance of 500mm when using wooden beams 200*100 mm provides the following overlap indicators: Load-bearing capacity 300 kg/m2, Weight of floor structures 140 kg/m2 |
|
We calculate the costs of erecting 1 m2 of floor structure.
Calculation of costs for installing a floor made of wooden beams over a cold underground. In addition to the material of the supporting structure, the calculation also includes materials for thermal insulation and leveling of the base for finishing the floor.
|
1. Lumber 1.97 m3 / 15,760 rub. 2. Fasteners 1 piece / 3600 rub. 3. Fire and bioprotection 1 piece / 7800 rub. 4. DSP 20mm 39m2 / 13380 RUR 5. DSP 10mm 39m2 / 8350 RUR 6. URSA PureOne 200mm 7.8m3 / 11,270 RUR 7. Vapor barrier and tape 1 piece / 2000 rub. 8. Leveling screed M300 thickness 50mm 3.9t / 10140 rub 9. Finishing screed 5mm 0.29tn / 7920 RUR Total cost of materials for 39.25 m 2 = 80,220 rub. |
1. Installation of the floor frame 350 RUR / 13,650 RUR 2. Fire and bioprotection 200 rub / 7800 rub 3. Installation of DSP 10mm 200 RUR / 7800 RUR 4. Installation of 20mm DSP 200 RUR / 7800 RUR 5. Installation of PureOne insulation 200 RUR / 7800 RUR 6. Laying vapor barriers. films 100 rub / 3900 rub 7. Performing a leveling screed M300 thickness 50mm 600rub / 23400rub 8. Performing finishing screed 200 RUR / 7800 RUR Total cost of workfor 39.25 m 2 = 79,950 rub. |
Total materials and work for the installation of floors on wooden beams: 4 081-00 rub/m2.
Floors on beams made of LVL timber.Scope of application: Interfloor ceilings in construction, frame housing construction, rafter system.
 |
 |
|
Below is a calculation of the costs of installing a floor using LVL timber. The span between the supports is considered to be 4.7 meters. The calculation also includes materials for thermal insulation and leveling the base for finishing the floor. Load bearing capacity 300 kg/m2 Weight of floor structures 55 kg/m2, the total “free” load-bearing capacity of the floor is 245 kg/m2 (according to SNiP “Loads and Impacts” for residential buildings the standard is 150 kg/m2). In the calculation presented below, the center-to-center distance between the beams is taken to be 625 mm to ensure waste-free installation of a 1,250 mm wide CBPB slab To simplify calculations, the following costs are given for a room of 8.3x4.7 m. |
|
We calculate the costs of erecting 1 m2 of floor structure.
Calculation of costs for installing 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 of the base for finishing the floor.
Total materials and work for the installation of floors on beams made of LVL timber: 2 942-00 rub / m 2.
What's in the bottom line?
Costs for erecting a floor structure for a house according to project 83-08.
Base area 124 m 2
Option 1. Floors made of precast reinforced concrete = 5,407 rub./m2 * 124m2 = RUB 670,468
Option 2. Floors made of monolithic reinforced concrete = 5,589 rub./m2 * 124m2 = RUB 693,036
Option 3. Floors on wooden beams = 4,081 rub./m2 * 124m2 = RUB 506,044
Option 4. Floors on beams made of LVL timber = 2,942 rub./m 2 * 124 m 2 = RUB 364,808!
It is worth noting:
As an example, we can cite a situation where the replacement of reinforced concrete floors with floors using LVL of timber and 44 conventional ceramic blocks for thermally efficient ceramic blocks Cayman30, for external and internal walls, significantly reduces the weight of the house.
Difference within house project 83-08 is:
Replacing a monolithic strip foundation with a monolithic pile-grillage foundation will also lead to a general reduction in the load on the foundation, by approximately another 99 tons.
The total reduction in the weight of building structures, and as a consequence of the pressure on the foundation, is 284.7 tons.
Reinforced concrete floors are the most reliable and durable and therefore are currently widely used in civil engineering.
By device method they are:
■ monolithic,
■ teams and
■ prefabricated monolithic.
The simplest type of monolithic reinforced concrete floor is smooth single-span slab. This type of floor, which has a thickness of 60...100 mm depending on the load and span, is used for rooms with side sizes up to 3 m.
For large spans they arrange beam floors, which can be:
■ teams and
■ monolithic.
So, if it is necessary to cover a room measuring 8 x 18 m (Fig. 6.4), beams with a span of 8 m with a step of 6 m are installed.
Rice. 6.4. Reinforced concrete monolithic ribbed covering: 1 - main beam, 2 - secondary beam, 3 - slab.
These beams are called main. Along them, after 1.5...2 m, they arrange the so-called secondary beams, having a span of 6 m. A slab with a thickness of 60... 100 mm is laid on top. Thus, the floor structure is ribbed. The height of the main beam can be approximately taken as 1/12...1/16 of the span, and the width as 1/8...1/12 of the distance between the axes. In ribbed floors, 50...70% of the concrete is spent on the slab. If this type of floor is made monolithic, then it is necessary to install formwork, carry out reinforcement work and lay concrete in a short time. 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 floor is called caisson(Fig. 6.5).
Rice. 6.5. General view of a reinforced concrete monolithic coffered floor.
Their use is mainly related to the requirements of solving the interior of the room.
Prefabricated reinforced concrete ribbed floors are much more economical than monolithic ones, as they make it possible to increase the industrialism of construction, reduce labor costs and the time required for construction and installation work. An important requirement for installing prefabricated floors is to reduce the number of mounting elements. The best option is when room-sized slabs are used.
A special kind A beam reinforced concrete floor is an overlap on beams placed in one direction with a pitch of 600... 1000 mm, and the filling between them is made of gypsum or lightweight concrete slabs, reinforced with wooden beam frames (for interfloor floors) or welded steel mesh (for attic floors).
Often, instead of rolling, double-hollow liner stones with a height of 250 mm and a length of 195 mm are also used. The gaps between stones and beams are carefully sealed cement mortar, which helps to increase the rigidity of the floor and sound insulation.
Elements beam floors They 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 columns, in the upper part of which there are thickenings called capitals.
Rice. 6.6.4. Reinforced concrete monolithic beamless floor:
a - general view, b - diagram of supporting the slab on the column, 1 - slab, 2 - capital, 3 - column.
The grid of columns for a beamless floor is assumed to be square or close to square with a side size of 5...6 m. The arrangement of prefabricated beamless floors is very effective.
The most widespread in civil engineering are slab floors. The main load-bearing elements of slab floors are different kinds reinforced concrete decking panels made from concrete.
Depending on the design schemes of buildings, they are (Fig. 6.7):
■ from panels resting with their ends on longitudinal load-bearing walls or on purlins laid along the building;
■ from panels resting with their ends on transverse walls or purlins laid across the building;
■ from panels supported on load-bearing walls or purlins on three or four sides;
■ from panels supported at four corners by frame columns.
Rice. 6.7. Structural diagrams of slab floors:
a - with longitudinal lines of supports, b - with transverse lines of supports, c - with support on three or four sides (along the contour), d - with support on four points (corners), 1 - floor panels resting 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-load-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 using anchors and fastened together with welded or reinforced ties. The seams between the slabs are sealed with mortar. Thus, fairly rigid horizontal disks are obtained, increasing 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 panels ceilings: 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 produced on installations with concreting combines, c - panels with oval voids, 1 - upper layer, 2 - middle layer, 3 - bottom layer.
Solid single-layer panels represent reinforced concrete slab constant cross-section with a lower surface ready for painting and a flat upper surface prepared for flooring, have a thickness of 100... 120 mm with a multi-layer 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 with a thickness of 140 mm are used, in which sound insulation from airborne noise is ensured by the mass of the slab itself.
Also used laminated solid panels(see Fig. 6.8, b), which is a reinforced concrete slab of constant cross-section, the bottom layer of which is made of durable concrete, where tensile reinforcement is placed, and the top layer is made of lighter and less durable concrete. These plates can also be three-layer.
Ribbed panels can be with ribs located both down and up. When the ribs are positioned upward, it is advisable to assemble the slab and floor structure at the factory, which increases the prefabrication factor and reduces labor costs on the construction site.
To increase the soundproofing ability of floors, layered structures are used, in which clean floors are arranged over soundproofing layers.
In Fig. 6.10, a - e show 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 consisting 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 - separate floor base panel, 5 - separate ceiling panel, b - load-bearing floor panel.
Thus, the installation of an air gap (Fig. 6.10, d) with a thickness of 80... 100 mm, located between two load-bearing panels or between the load-bearing part of the floor and the structure acoustic ceiling(Fig. 6.10, c, e) or floor (Fig. 6.10, b), allows you to provide the necessary soundproofing ability of the ceiling. For this purpose, ceilings made of panels with ribs down and a separate ceiling are used.
Frequently ribbed ones are effective in this regard. panels, consisting from two vibro-rolled shells(see Fig. 6.8, d), one of which forms the base for the finished floor, and the other serves as the ceiling. Solid air gap and soundproofing gaskets between the slabs provide the necessary sound insulation of the floor.
Hollow-core panels widely used for flooring. They are most often made from concrete 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 are labor-intensive to manufacture. It must be borne in mind that the cost of hollow-core panels is relatively high.
Also used tent panels(see Fig. 6.8, d), which have the form of a slab framed along the contour with ribs facing down in the form of a cornice. Made to fit a room, they allow you to exclude crossbars and other beam elements from the structural design of the building, and due to their small thickness they allow you to reduce the height of the floor without reducing the height of the room.
When constructing public buildings, there is often a need to install floors with spans of 9, 12 and 15 m. For this, the following is used:
■ ribbed prestressed slabs 9 m long, 1.5 m wide and 0.4 m rib height (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 constructing floors.
Rice. 6.11. Flooring slabs for spans of 9, 12 and 15 m: 1 - mounting loops, 2 - longitudinal ribs, 3 - transverse ribs.
In this article we will talk about what methods there are for constructing a monolithic floor, and you will also learn about the advantages and disadvantages of these methods. The article will tell you about the basic requirements for the thickness and reinforcement of reinforced concrete floor elements.
Reinforced concrete is an almost eternal material. From it they create many structural elements- beams, walls, lintels. One of the most difficult, at first glance, products is the ceiling. However, the labor intensity of construction is fully compensated by the performance properties of the finished product.
Advantages of monolithic flooring:
Disadvantages of concrete floors:
Reinforced concrete floors are suitable for permanent structures designed for a long service life, as well as for premises where significant static and dynamic loads are provided - workshops, hotels, dormitories (with partitions made of stone material).
In private construction, monolithic floor slabs are usually installed on brick walls, since concrete walls are much more difficult to construct than brick walls.
Because of the big specific gravity concrete (2400 kg/m3), products made from it are heavy. The weight of the product can be reduced by reducing the portion of concrete in the structure, that is, simply making it thinner. The rigidity is compensated by reinforcement. Sufficient thickness of reinforced concrete elements:
The thickness of these elements will be considered sufficient only if reinforcement rules are observed. Calculations and many years of practice have shown that there is an optimal balance of mass, volume, cross-section and load-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).
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 located at a height, the formwork for it has the form of a table: a solid plane that fills the space between the load-bearing walls (and columns) on a spatially rigid frame of racks and slopes. Formwork happens three types, but one requirement is constant for any of them - a reliable foundation.
A set of factory products, which includes:
This set is professional—inventory formwork is used to build high-rise residential buildings. It is reliable, convenient and designed for continuous use. Purchasing a kit for installing one ceiling will not justify itself - all the products are made of steel and are not cheap. The solution may be to rent formwork. The company's specialists will themselves calculate the required quantity of each element for your facility.
The undoubted advantages of this approach are the speed of installation of formwork and ease of operation, as well as the quality of the plane. Disadvantages include the risk of delaying the rental period.
All elements of the “table” for the ceiling 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 available material. Obvious disadvantages:
Provides for the partial use of inventory formwork elements and lumber.
In this case, you can use factory racks with tripods and crowns, and make the beams and formwork flooring from boards. Or rent laminated plywood and assemble the “table” frame from available wood. There can be many combinations.
To construct the reinforcement frame of a suspended reinforced concrete floor with a thickness of 200 mm, a mirror mesh of A3 reinforcement Ø 16 mm with a cell of 150-180 mm is used. When using concrete prepared on site, we recommend strengthening the frame using a smaller rod spacing of 150 mm. If the concrete is factory-made, a step of up to 200 mm is allowed. In places of support and abutment of elements (support on a wall, column, capital), we recommend making reinforcements - adding rods.
There are rules for concreting that must be followed unquestioningly in order not to subject the structure to destruction in the future:
