Floor slabs are finished reinforced concrete products that are used in the construction of multi-storey buildings, industrial buildings and roads. Due to their versatility, floor slabs can also be used in the construction of summer cottages, cottages.
Despite the prefabricated installation system, the slabs provide a continuous floor layer, which contributes to good sound insulation and thermal insulation of the entire structure.
RC slabs are available in the price , are easy to install, with their help a high floor strength is achieved.
However, it should be remembered that slabs made of concrete mixes are installed on reliable, sturdy supports, also try to protect them from moisture.
There are different sizes of reinforced concrete floor slabs.
For convenience, all technical characteristics are collected in a special GOST 9561-91.
Here are all the requirements that must be observed when making hollow-core reinforced concrete slabs from light or heavy, dense silicate concrete.
There are three types of floor slabs :
To understand what size of floor slab is needed, look at the marking.
All the necessary characteristics are indicated in GOST.
The first letters indicate the type:
PB - solid concrete slabs;
NV, NVK, 4NVK - ribbed reinforced concrete slabs;
PC - hollow.
The third letter in the marking indicates the presence of an additional support side of the plate:
T - three sides;
K - four.
The first two digits are the length in decimeters.
The second two are width.
Usually these parameters are overestimated by 10-20 mm.
The last digit indicates the design load .
In the next group of letters and numbers, additional construction parameters may be indicated, such as the class of reinforcement, the presence of mounting loops, etc.
Example and decoding of marking
Let's consider the example of PK 54.15-8:
PC - hollow slab;
54 - slab length, dts;
15 - width, dts;
8 - design load, 7.
85 kPa (800 kgf / m2)
Dimensions and characteristics of solid slabs are specified in GOST 12767-94.
The first number in the marking indicates the thickness of the product :
The length of the concrete floor slabs ranges from 3 to 6, 6 m, in width - from 1.2 to 6.6 m.
B regulatory documents determine the presence of ready-made concrete slabs structural elements , for connection with metal and reinforced concrete elements of the frame, mounting loops , as well as channels for wiring communications .
Dimensions of ribbed reinforced concrete slabs are specified in GOST 27215-87 for slabs 400 mm. , in height and GOST 21506-87 for prestressed plate 300 mm. , height.
1P - the product rests on the ledger shelf; there are eight types from 1P1 to 1P8, where the length of the product is 5.
55 and 5.05 m, and the width is 0.74-2.985 m
2P - the product rests on the body of the crossbar, that is, on the support beam; the dimensions of the slab are always 5.95 m in length and 1.
485 m in width.
The manufacturer must comply with the requirements of the standards specified for ribbed reinforced concrete slabs. These are embedded rods and all kinds of tolerances and requirements for reinforcement.
The dimensions and sizes of hollow core slabs of the PK are specified in GOST 9561-91.
Plates are classified into groups , where, in addition to the third letter (T or K), which determines the number of support sides, hollow ceilings are designated by the letters PG or PB .
The voids in the SG slab should resemble a pear shape, and the PB should be made using the continuous formless molding method.
Depending on the type and size of the reinforced concrete floor slab, the method of its manufacture, materials, the price of the product changes.
Do not forget about the delivery and installation, which is carried out with special lifting equipment.
The most common type of floor slabs are hollow.
Despite the fact that they are inferior in strength to solid slabs, still for the construction of summer cottages, private houses, cottages are ideal, since such structures do not imply a high load.
Hollow core slabs are well protected from fire, moisture and decay. Voids not only dampen unwanted vibrations, but also make it easy and convenient to carry out communications: an electric wire, a sewer riser, etc.
When installing slabs, whether it is the foundation of a house or a floor, it is very important to calculate the support parameters so that in case of an error, the destruction of the building does not occur. Typically, the support area is approximately 12 cm on each side.
The slab is laid on a semi-dry mortar, and the remaining cracks and holes are sealed with a special insulation and cement.
( 3 marks, average 5 out of 5 )
Posted By: Work Style |11, Nov 2020
Posted By: Work Style |11, Nov 2020
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