Marking
Plates of overlapping call horizontal structural elements of a rectangular building that divide the space on floors. In addition to the carrier function, such plates are part of the “skeleton” of the structure, responsible for the rigidity of the entire building. They are based on concrete, Therefore, they have a number of advantages: durability, durability, fire resistance, resistance to atmospheric influences. By minuses include: relatively high mass, presence of eigen voltage, high heat and sound conductivity.
In order to simplify the design and construction of the overall dimensions led to a specific standard. Now the developer does not need to know all the subtleties of production technology, it is enough to be able to decipher the labeling. The label is understood by encrypted information about the size, main strength and design indicators.
It is performed according to GOST 23009 and is divided into 3 groups that are divided by a hyphen. The first group includes panel type data, second geometric characteristics (length / width). The third group indicates the strength indicators, the class of steel reinforcement and the type of concrete. We will analyze the decoding of PC-48.12-8AT-V-T, where:
- PC – Empty panel;
- 48 – Length 48 dm (4.8 m);
- 12 – width 12 dm (1.2 m);
- 8 – under a uniformly distributed load of 800 kg per m2;
- AT-V is strained fittings (AT-V class);
- t – type of concrete heavy.
The height of the element 220 mm is not specified, as it is standard for this type of product. Depending on the method of production, the plates are divided into:
- prefabricated (factory);
- Monolithic.
The second is made directly at the construction site.
The process consists of assembling formwork, installation of reinforcement rods and grids, laying concrete and dismantling formwork. Based on a constructive solution, reinforced concrete plates may be.
- Solid (full). Flat panel with high strength, low sound and thermal insulation. Simple enough in the manufacture, but more material. Possess an impressive weight (600-1500 kg) with small sizes. Most often used as inter-storey overlaps of high-altitude structures.
- Ribbed (P-shaped panels). Their distinctive features are alternating thickened and thinner elements, due to which the necessary resistance to bending is achieved. More often used in the construction of industrial structures, since in housing construction such configuration is poorly finished. (P2)
- Empty. Are the most common type of concrete products. They are a parallelpiped with cylindrical voids, thanks to which the stove works well for a bending moment, withstands heavy loads, allows you to block large spans (up to 12 meters), facilitates the gasket of communications.
- PC – the most popular type of w / w overlap, inside there are holes with a diameter of 140 mm and 159 mm, the thickness of the product is 220 mm.
- Pnto – Modernized model having a smaller thickness of 160 mm. It can withstand heavy loads due to thicker reinforcement rods. Easier than ordinary crowded models, so this option is more economical.
- PPS (polystyrene foam, bp) – panels stand, new generation, are manufactured by non-blank molding, which allows the development of its sizes to. The minus here is the high cost.
Standard dimensions
Standard sizes of plates are indicated in GOST 9561-91. We give them in the form of a table.
Type of plates | Length (m) | Width (m) |
PC (1PK, 2PK, 3PK) The diameter of voids is 159 mm, with support on two sides | from 2.4 to 7.2 times 0.3 up to 9.0 | from 1.0 to 3.6 multiple 0.3 |
1PK | ||
PKT (1PT, 2PT, 3PT) with a diameter of a hole 140 mm | 1.8 / 2.4 / 3.0 / 6.0 | from 1.2 to 3.6 multiple 0.3 |
Pnto | from 1.6 to 6.4, there are up to 9.0 | 0.64 / 0.84/15 / 1.2 / 1.5 |
PG | 6,0 / 9.0 / 12.0 | 1.0 / 1.2 / 1.5 |
Ribbed | 6.0 | 1.5 |
Solid, height 120 mm | 3.0 / 3.6 / 6.0 / 6.6 | 4.8, 5.4 and 6.0 |
Solid height 160 mm | 2.4, 3.0 and 3.6 | 2.4 / 3.0 / 3.6 / 4.8 / 5.4 / 6.0 |
Weight
Weight is one of the most important characteristics. In addition to calculating the distribution load, it will depend on it, how the slab will be delivered to the construction site and mounted. For this, the crane load capacity is calculated. Installation, as a rule, is made by an autocrante with a minimum capacity of 5 tons.
Range of mass of products in Russia varies from 960 kg to 4.82 tons.
Table “Standard Mass Products”
Type of plate | Thickness, mm | Width, mm | Length, mm | Calculated distribution load without taking into account your own weight, kg / m2 | Weight kg / 1m n. |
PC | 160 | 1500 | up to 7200 | 400 – 2100 | 404 |
PC | 220 | 1500 | up to 9600 | 400 – 2400 | 520 |
Specification of standard PC | |||||
PC 48.12-8AT-V-T | 220 | 1190 | 4780 | 1700 | |
PC 48.15-8AT-V-T | 220 | 1490 | 4780 | 2250 | |
PC 51.15-8AT-V-T | 220 | 1490 | 5080 | 2400 | |
PC 54.12-8AT-V-T | 220 | 1190 | 5380 | 1900 | |
PC 54.15-8AT-V-T | 220 | 1490 | 5380 | 2525 |
How to calculate?
Initially, it is necessary to correctly compose the plates on the plan. Basic rule: Overlapping plates are based on two sides. Since the slab is the working reinforcement, Cannot be allowed local loading (racks, columns). An important moment will be on which walls will be relying (walls of slag concrete, brick, concrete), which affects the calculation of loads.
Determine the calculated plate length. It is less real and is the distance between the most remote adjacent walls. Sets geometric parameters. Next Stage – Harvesting Loads. In order to determine the load on each product, it is necessary on the plan to designate all severity acting on overlaps.
This includes: sand-cement ties, thermal insulation, floor coverings, partitions.
Having arouses these components, you need to divide the value to the number of plates. Thus, you can get an extremely permissible load on each product.
Naturally, It is impossible to maximize the framework of the building in order to avoid achieving the critical level, for this is calculated the optimal value. For example, a stove weighs 2400 kg, it is intended for a platform of 10 m2. Need to divide 2400 to 10. It turns out that the maximum allowable value is 240 kg per 1 m2. The weight of the product itself should also be taken into account, on which the load was calculated (suppose that its value is 800 kg per 1 m2). Then it is necessary to reduce 240 from 800, which gives an indicator of 560 kg per 1 m2.
Next step is needed approximately assume the weight of all loading items. Suppose it is equal to 200 kg per m2, then from our previous indicator 560 kg per m2 we take 200 kg per m2 and get 360 kg per m2. The last stage determine the weight of people, finishing materials, furniture. On average, it is 150 kg per m2. Then from 360 you need to take away 150. We got the optimal load of 210 kg per m2. Calculate the maximum bending moment can be calculated by the formula: Mmax = Q * L ^ 2/8, where L is the length of the span.
At the next stage The class of concrete and the cross section of the reinforcement. The latter action is to verify the limit states.
Drawing 1. Layout plates in the panel house.
Drawing 2. A private house.
Drawing 3. Multi-storey building.
Video about sizes and weighing floor slabs See below.