Hollow core slab: element for the reliability of the building

The basis of any ceiling and floor lies hollowcore ekrytiya lane, which plays a role of horizontal supports, directly influences the stability of construction. Neither panel or frame building is not complete without these plates, which are made all the floor slabs. Basically, the material is made of various types of concrete. A characteristic feature - the presence of longitudinal voids, and the main advantage - light weight and long life.

Basic types and sizes of hollow core slabs

More recently regulated the hollow core slab production process with GOST 9561-91, according to which the products have special labeling. The passport to the building material comes with a certificate indicating the size, the brand used in the production of concrete and load, which is calculated on the stove.

Said GOST was developed in the Soviet times, and obviously in need of improvement. Therefore, from June 1, 2017 enacted a new standard, acting on the territory of the Russian Federation. According to the International Standard 9561-2016 hollow floor slabs are distinguished by new transport rules, methods of control and general technical requirements. It is these rules are now a fundamental in the development of products and specifications, as well as in the preparation of typical design documentation.

It is interesting! Rules governing the hollow core slab production process Series 1.141-1, were developed in the USSR State Construction Committee of 28 May 1970 and to this day remain valid on the territory of Russia.

Reinforced concrete hollow core slabs commonly used in the construction of precast buildings. Depending on the characteristics of the production of hollow articles are divided into plates and formless. The width of the hollow-core slab has several meanings:

• 1m;
• 1.2 m;
• 1.5 m;
• 1.8 m.

The thickness of the hollow-core slab largely unchanged and is 22 cm, although variants can also be found thickness of 16 or 30 cm. The length can vary depending on the manufacturing method that does not affect the reliability of the construction material. Basically lengths indices ranging from 1.7 to 9 m.

Sizes and prices of hollow core slabs:

Parameters: length, width, height, m	Minimum price, rub. / Pcs.	The maximum price, rub. / Pcs.
1780h990h220	2780	3469
2080h990h220	3483	3766
2580h990h220	3840	4356
3180h1490h220	5601	7766
3780h1190h220	5619	7493
5380h990h220	6886	7938
7180h1490h220	12843	18686

In a separate group can distinguish lightweight inner lining plates, which are labeled PNA. The main difference from the standard plates - height, which is equal to not 22, and 16 cm.

Table size, lightweight slabs price:

The size of hollow slabs: length, width, height, m	Price, rub. / Pcs.
1580h990h160	2173
1780h1190h160	2584
1780h1490h160	3294
2080h1490h160	3812
2980h990h160	3257

The main types of labels: which data can be found in the name

Standard labeling floor slabs, regardless of species, has these values:

• letters denoted by product type and design features;
• figures marked length and width, the height is considered to be relatively constant value and marking is not used;
• load bearing capacity, where the unit value corresponds to withstand a load of 100 kg / m²;
• Class used reinforcement is usually indicated at the end.

Occasionally encountered in labeling and additional values, such as resistance to aggressive environments, seismic impact, temperature extremes. You can also find a value that indicates the number of cavities in the panels. On the example you can see transcript labeling hollow articles PC 23.15-8:

1. PC stands for that the overlap produced by pouring into finished formwork, and the plate has a circular cavity.
2. 23 - denotes the length in dm, which is most often rounded up.
3. 15 - the width of the rounded plate 14.9 dm.
4. 8 - value indicating the load bearing capacity of the hollow block, which corresponds to the indicator 800 kg / m².

Similarly, PB stands and overlapping designation 72.15-12,5:

1. PB - these letters marked product made by the method formless. Abbreviation also means that it is a plate with cavities cylindrical shape.
2. 72 - length of the rounded value of 71.8 dm.
3. 15 - width option.
4. 12.5 - coefficient indicating the bearing capacity of the article which corresponds to 1250 kg / m².

What are and how they are made hollow-core slab

In the manufacture of hollow slabs of hollow formwork types are used that limit plate for special contour. For this reason, the length of the finished slab varies from 1.8 to 7.2 m in size increments of 30 cm. The production process is as follows:

1. A solution of concrete poured into the formwork stationary metal with a fixed armature and a metal grid.
2. Concrete mix well compacted, after which the finished boards be processed under hydrothermal boxes.
3. After complete solidification of the final panel is removed from the casing of the pre-mounted eyelets.

Formless plate produced without the use of concrete formwork in continuous casting. The final form of the product gives a molding machine, resulting in a long range, which already then cut to the required size, the accuracy can reach several centimeters. The maximum length of the slabs in this case is 9 m, height remains unchanged and is 22 cm. The main advantage of formless plates is that the cutting edge can be given any shape that corresponds to the architectural idea of ​​the building.

Most often encountered in selling slabs made of shuttering principle because it does not require additional equipment to use to create them. This type of plate is made in almost all the factories that manufacture of precast concrete.

For the convenience of transportation and the construction of all products are equipped with mounting brackets. To give boards more stability, additionally held their reinforcement. The rope is used as reinforcement of wire or other high strength material. It is the use of reinforcement increases the strength of the supply of products and allows the plates to withstand high loads during operation.

To manufacture the concrete brand W4, having an index A22,5 strength and load bearing strength themselves overlap is in the range 2000-2400 kg / m3. Most often used these types of concrete panels for the manufacture of:

• silicate;
• light;
• heavy.

In general, hollow-core slabs are made of these materials:

1. Concrete. Products are made from Portland cement M300 or higher. It is the quality of the concrete used and depend on strength values ​​of finished products.
2. Steel reinforcement. The use of the reinforcing material belonging to the class of A3 and A4, increases load properties plates used as intermediate floors.

Hollow core slab: structural features

The main advantage of using the corresponding standard GOST hollow core slabs - a significant simplification of the process of construction and laying of utilities. In addition, panel production finished building features provide enhanced thermal insulation intermediate floors. plates also ensure improved sound insulation and prevent infiltration of external noise into the room. Among the main design features are such moments:

1. The correct geometric shape. The finished products are different form the box, which has a smooth surface facets.
2. The presence of the through holes with the front sides. The presence of internal voidage increases the sound and heat insulating properties and also reduces the weight of the final slab.
3. The correct form of internal cavities. The configuration of the longitudinal section of the cavity has the form of a perfect circle or oval.
4. The dimensions of the hollow slabs. In general, the length, thickness and width of the plates, as well as the diameter of the internal section of the holes depends on the manufacturer, but primarily regulated by the GOST standards.
5. The number of internal bores. GOST hollow core slabs have from 5 to 9, the through holes.

Interesting information! The presence of voids within the slabs and ensures high performance products. Unlike whole panels hollowcore weight significantly lower, respectively, will be provided on the foundation minimal impact. In this case, the hollow plates are not inferior to solid panels or for sound insulation or for insulating properties.

The main advantages of the use of hollow slab

The main advantages that are hallmarks of hollow core slabs, are:

1. Reduced weight. At the same size hollow-core slab and integral first panel weight will be less. The presence of voids does not affect the reduction of the safety margin, but less hollow-ware loaded foundation base of the building.
2. A more affordable cost. Price hollow slabs significantly lower than the cost of monolithic panels, because a smaller volume of concrete used in the production process, which allows us to reduce production costs.
3. Enhanced sound and thermal insulation properties. Due to the presence of voids formed by the air gap, which is within the concrete mass and provides high performance properties.
4. Shortened the time required for construction. Installation work with any size of hollow core slabs are carried out in a relatively short timing, especially when compared with the construction of monolithic concrete structure with formwork.
5. Large assortment of floor slabs. The producers have a decent sized series of products, which differ in terms of product parameters and characteristics. Large selection of standard sizes allows you to choose different plates for the construction of complex structures overlap.

Useful advice!Only products manufactured in industrial conditions, are able to comply with current standards. Plates, manufactured in makeshift conditions in small enterprises, will have only a small standard size.

Main positive and negative plates using

Other advantages that distinguish the different size of overlap plate:

1. Internal through holes can be used for the construction of different kinds of communication and does not have to prepare for them special Stroebe.
2. Increased resistance of concrete products to humidity and temperature fluctuations of the medium.
3. Ability to withstand vibration loads, which makes it possible to use plates for the construction of buildings in areas with high seismic activity. Subject to the rules of construction of the building is able to withstand shocks amplitude 8-9.
4. Smooth surface panels facilitates internal finishing works after construction.
5. The minimum exposure hollow product shrinkage.
6. Increased resistance of concrete to the appearance of corrosion processes.

In addition to these advantages, builders are also isolated by the fact that the application of hollow floor slabs is no need for installation of additional struts. Despite so many advantages, the plate also has some negative aspects.

Thus, the great weight of the concrete slab causes that need to be further used in the construction of lifting equipment. Due to the fact that the manipulator must be ordered, first, you must give him sufficient size construction site, and secondly, you will need to make in the budget article additional costs.

Related article:

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Also, before you start building, you will need to calculate the bearing capacity of hollow core slabs and to estimate the maximum possible load. At the same time we must take into account the magnitude of the impact of both static and dynamic character, and to calculate the load capacity of the walls.

Important! Before forming the overlap of the hollow panels previously required concreted Laying nets disposed along the contour of the box. In order to prevent freezing of the plate, inside the hole in the end corners are sealed by means of insulation and cement.

Types of loads, which are designed floor slabs

According to the standard value of the product carrier capability equals 800 kg / m², but there are also options, designed for increased load in the range 1200-1600 kg / m². It should be borne in mind that the cost of this type of hollow core slab will be higher. Basically panel tested two types of loads:

• static;
• dynamic.

Static load - the combined impact on the plate exerted by the floor covering, together with the mass of screed. This is also the weight of interior walls, installed furniture - all this makes the total pressure exerted on the product. Below there is an additional burden in the form of ceiling fixtures, drywall constructions, enshrined eaves and the rest of the attachment, which is used during installation ceiling.

With regard to dynamic loads, they are the result of movement of all residents. In addition, dynamic load create a set of sports trainers, as well as sliding partitions, which are mounting on the floor or on the ceiling.

A separate category is allocated a complex load, which, for example, may include pressure, exerted bath, which varies depending on the filling bowl, the presence or absence therein person. If the tub is mounted on legs, each of the supports on the plate will create a local pressure.

How to find out the maximum load on the floor slab Hollow core

To calculate the pressure in the construction, which is calculated on a reinforced concrete base with cavities need to perform these steps:

1. Draw a detailed plan built taking into account the number of supports, which after completion will have a load on the carrier board. Note how they will house.
2. Roughly estimate the total weight of elements providing pressure on the overlap.
3. Divide the calculated value of the number of concrete panels.

After calculating the maximum planned load on the plate should choose the most suitable for the characteristics of the product type. In the calculation we should not forget that the curb weight plate is also taken into account. With regard to the calculation algorithm for the supporting structure labeled PC 23.15-8 with capacity 800 kg, which is different in size 1,49h2,29 m and a total weight of 1180 kg, it will look as follows way:

1. To learn footprint, you need to multiply the length by the width: 1,49h2,29 = 3.41 m².
2. For the calculation load on the total weight of the square base plate divided by the area of ​​1180: 3.41 = 346 kg / m².
3. Then, by carrying capacity consuming obtained value 800-346 = 454 kg.

The resulting figure is the maximum weight for which plate is designed taking into account its own weight. For the total mass of all acting on top of the plate items per m² is usually charged an amount equal to 250 kg. Thus 454-250 = 204 kg - that this weight can be regarded as reserve strength m² panels.

Interesting information! Most of the concrete products is the carrying capacity of 800 kg / m², which is considered optimal for premises.

Weight slabs and other important parameters of products

GOST dimensions hollow floor slabs must be within the following values ​​shown in the table:

Options	Minimum value	the maximum rate
Length m	1,68	12
The width of the floor slabs, m	0,98	1,48
Thickness, cm	16	30
The diameter of the voids, see	11,4	15
grade of concrete	M200-M400
Weight, kg	750	4820
The bearing capacity, kg / m²	800	1200

If ordered products under individual production, all figures may vary depending on the requirements of the buyer. Change the settings in any case should not affect the reliability or manufacturing technology. Although the thickness of the slabs varies, most of finished product is equal to 22 cm.

Weight is considered particularly important criterion, all products are manufactured in factories in Russia, different rates of 750 to 4820 kg. The mass of the product is important to consider, because the basis of the values ​​determined by way of panel installation during construction. Typically, a small construction site cranes are utilized capacity of up to 5000 kg. If the stove will be more difficult, it can lead to serious problems.

For example, concrete slab volume of 2.91 m³ labeled PC 89-15.8 has a length of 8.88 m, width 1.49 m and a standard height of 22 cm. The product with the following parameters different weighing 4150 kg, in which case the use of cranes to 5 tons may be dangerous. It should be noted that in some cases the weight of the plates with the same label can be different, but usually the difference is not more than a few kilograms, so the essential role it plays in the calculations. The most common weight changes due to wetting of a product.

Table weight hollow slabs depending on size:

Size: length, width, height, m	Volume, m³	Weight, t
1680h1190h220	0,44	0,61
1980h1190h220	0,54	0,76
2380h1190h220	0,62	0,905
2680h990h220	0,58	0,83
1780h1190h160	0,34	0,463
2080h1490h160	0,5	0,686
5780h990h220	1,26	1,71

Hollow concrete floors are widely used in the construction of multi-storey buildings both private and public buildings. His distribution of the panel obtained by high performance characteristics that are appreciated by users and professional builders. To accelerate the construction, the main thing - to choose the correct size, weight and type of plate, while not forgetting to take into account the carrying capacity of products. As a result of the construction of compliance with the rules and technologies, when used hollow floor slabs, get high-quality and sustainable building.