Reinforced concrete steps: regulatory documents and

Is there a GOST for reinforced concrete steps? According to what regulatory documents are marches and staircases made of reinforced concrete? How are they mounted during construction? Let's figure it out.

List of standards

Let's start with regulatory documents.

Полезно: GOST 9818-85 содержит техническое описание не только маршей и лестниц, но и производящихся отдельно бетонных проступей для них.

Content standards

What do the documents mentioned by us say?

GOST 8717.0.-84

The scope of reinforced concrete steps we have already mentioned - inside and outside buildings. GOST gives a more detailed definition: it is permissible to use them outside heated buildings in climatic zones with the coldest five-day period of the season, having an average temperature of -40 degrees. Contact of concrete with aggressive media is permitted, which allows the use of products in production (including at the enterprises of the chemical industry).

The steps are divided into the following categories:

• BOS - the main.
• LSV - frieze upper (adjacent to the site).
• LSP - pad liner.
• LSN - frieze bottom.
• LSS - flat for through marches.

The main material for the products is reinforced concrete; however, the main LS stages with a length of up to 1.5 meters can be made without reinforcement.

The maximum short-term load for reinforced concrete products is 6 kPa, or 600 kgf / cm2.

Nuance: the design load does not take into account the own weight of the stage. However, on a solid basis, it must be completely transferred to this very base, without loading the step.

The standard stipulates that reinforced concrete stair steps are made with steel embedded parts for fastening fences. By agreement with the customer, however, mortgages can be replaced with sockets.

The flat steps of the LSS, in addition, are completed with mortgages for attachment to kosoura (support beams of the march) with a width of 155-180 mm; for a specific project can be installed additional mortgage elements.

If necessary, the products are made left and right - depending on the direction of climbing stairs. As a rule, this parameter affects only the location of mortgages or nests for mounting fencing.

Depending on the project and in agreement with the customer, the steps can be supplied with or without mounting hinges. In the second case, the use of loading equipment with special grippers is implied: concrete products cannot be slinged.

Steps made of lightweight concrete must have at least a 15 mm thick layer of heavy concrete or an abrasion resistant coating made of synthetic materials on their faces.

The finish of the top surface within the standard may vary.

What options are possible?

1. Smooth concrete on ordinary cement.
2. Decorative concrete - on white, colored cement or marble gravel.
3. Mosaic concreteobtained by grinding concrete on marble rubble and / or on white and colored cements.

What can be the size of the staircase steps?

• Width varies from 900 to 2380 millimeters.
• Height ranges from 100 to 168 mm.
• The depth of tread - from 260 to 330 mm.

Reinforced concrete stacked steps weigh from 45 to 187 kilograms. If you are not an experienced athlete-athlete - obviously, it is not worth taking up and moving these products with your own hands, without loading equipment.

Variants of step designs are described by a related regulatory document - GOST 8717.1-84.

Marking

It consists of alphanumeric groups and hyphens between them.

1. The first group indicates the type of stage and its dimensions, rounded to whole numbers. At the same time height of 145 mm is not displayed.
2. In the second group there are letters B - for concrete main steps, L - for products made of lightweight concrete and C - for silicate. Reinforced concrete precast steps made of dense concrete, referring to types other than BOS, are not marked with the second alphanumeric group.
3. In the third group are present:

• Figures 1, 2, 3, etc., indicating the presence of mortgages or nests for fences. Figure 1 corresponds to the design provided by GOST 8717.1-84; other numbers refer to the project documentation.
• The letter L designates the left execution of a step (for stairs with a fence on the right side).
• Буква Г означает гладкую поверхность бетона на белом или цветном цементе, буква Ш - шлифованную мозаичную поверхность. Smooth concrete на обычном цементе отдельно в маркировке не указывается.

• M means increased frost resistance (possibility of operation at -40 ° C and below). P - high density, allowing the use of products with constant contact with aggressive media.

Marking Samples

Let's give a couple of examples and analyze them.

Technical requirements

GOST for prefabricated stairs and steps for them imposes certain requirements on the materials used and, of course, the quality of the finished product.

• The compressive strength of concrete for external staircases must not be lower than grade B25. For internal ladders use of concrete of the B15 brand is allowed.
• The average density of light and silicate concretes should not be less than 1800 kg / m3.
• For products intended for operation in the open air, in unheated rooms or at constant relative humidity above 60%, the valve is protected from corrosion. The way is stipulated in the project documentation.

Useful: traditionally used for the protection of paints. However, it is now easy to find a more effective means on the market — a phosphating rust converter that creates a durable film of chemically converted iron oxides on the surface of corrosion-resistant steel. The price of the material starts from 200 rubles / kg.

GOST 9818-85

The standard specifies the manufacture of products of the following types:

Estimated loads without its own weight are:

• 360 kgf / cm2 for residential buildings.
• 480 kgf / cm2 for public buildings and industrial construction.

All elements can be made in the left and right execution.

Surface options are slightly different from those discussed above, within the previous standard:

1. Smooth concrete surface on ordinary cement.
2. Ground concrete surface on white cement, colored cement or marble crushed stone.

Clarify: this type of finish is allowed only for landings and overhead treads.

1. In addition, the site can be finished with ceramic tiles, providing maximum wear resistance of the surface.

Marking

Она и здесь состоит из нескольких групп, разделенных дефисами (см.также статью «Шлакобетон – все, что нужно знать о данном виде материалов»).

The first group indicates the type of item and its dimensions. In general, the length and width in decimeters are indicated; for staircases, their height is additionally indicated (projection onto a vertical plane).

Nuance: for an LMP march with one upper semi-platform, the length is indicated equal to the length of the march with two semi-platforms belonging to the same type.

The letter B in the first group means that we face the final platform or invoice tread for the upper final step.

The second group contains:

• For platforms and marches - the calculated load (figure 4 corresponds to a load of 360 kgf / cm2, figure 5 - 480 kgf / cm2).
• For overhead treads - the left execution and the type of surface finish (Ш - polished mosaic; the absence of letters indicates a smooth concrete surface)

In the third group may be present:

• The letter L, denoting the left execution of the march or platform.
• The letter K for the site means the presence of support consoles. The letter M is a technological opening for the garbage chute. The letter Y - gain to support the march.
• In the case of the LMP march, the number 1 indicates the elongated upper semi-platform, 2 indicates the elongated lower semi-platform, 3 indicates the absence of the lower semi-platform.
• W - again polished mosaic surface, K - facing with ceramic tiles.

• The letter C speaks of increased seismic stability of the structural element of the ladder. Such products are used in the construction of buildings designed for 7-9 points on the Richter scale.

Marking Samples

Technical requirements

They relate to the type of reinforcement used, the abrasion of the surface, the quality of concrete and the maximum allowable deviations in linear dimensions.

Installation

How are reinforced concrete staircases, stacked steps and other elements of stairs mounted? It is clear that this work is rarely done by hand with an untrained person; it is also clear that a professional builder hardly needs installation instructions.

If so - we will pay attention only to the main points.

• For the alignment of the marches used wooden templates.
• Installation маршей и площадок производится с помощью подъемного крана. Стропы цепляются за монтажные петли; в случае их отсутствия используются стальные захваты из профилированной трубы.

• Lapping to the desired position is carried out manually, crowbars. The march is first set edge on the lower platform; the top edge is set to the desired position and is deposited on a pad of cement mortar.
• Steps can be installed on kosoura both with the help of heavy machinery and manually.

Let's clarify: it is clear that only steps weighing up to 80-100 kg can be mounted manually. Carrying and installing steps weighing 150-180 kg is not only problematic, but also dangerous.

• Steps stacked along the march from the bottom up. Sand-cement mortar is poured on the edge of the lower step, after which the next element of the ladder is installed on top. Proceed simply stacked on the solution.

• In order to make mounting holes that are not foreseen in the manufacture of elements, abrasive cutting of reinforced concrete - concrete with diamond circles, rebars - with ordinary cutting circles on metal or gas cutting torch is used.

It should be borne in mind that the failure of the reinforcement dramatically weakens the structure: during the construction of multi-storey buildings, such modification is prohibited. Diamond drilling of holes in concrete, along with conventional drill drills, is used to make additional sockets when installing fences.

Conclusion

Будем считать наше знакомство с железобетонными лестницами и производимыми для их сборки изделиями состоявшимся (см.также статью «Железнение бетона: способы, материалы, последующая обработка»).

As usual, the video in this article will offer the reader more information. Successes!