SU67400A1 - Composite beam of sheet asbestos cement or similar material. - Google Patents

Description

The invention relates to the construction of thin-walled beams, made of sheet asbestos cement or similar material and laid out in the form of solid coatings for the device of floors. In order to obtain beams of increased bearing capacity, the flanges are reinforced by overlaying additional sheets in those parts of the length (beams that experience increased stresses.

A distinctive feature of the beam design according to the invention is that the wall thickness increases by one or several sheets in those areas where the thickness of the shelves is reduced by the same number of sheets.

In FIG. 1 shows a general view of a composite beam of sheet asbestos cement; FIG. 2- floor made of such beams, in cross section; , p 3-6 - various lrofili composite beams; FIG. 7 shows the construction of reinforced asbestos-cement beams according to the invention in longitudinal and transverse sections; FIG. 8 - axonometry of the same beam; FIG. 9 - form for consuming composite asbestos cement beams.

The thin-walled beam is made from strips of sheet fiber cement material, such as asbestos cement, and consists of two or three elements: the upper and flat shelves are made with the longitudinal orientation of the fibrous fibers; the walls, in the form of one semi-closed box-shaped profile or two box-shaped or Z-elements, are made with the transverse orientation of the fibers (Fig. 1). This fiber orientation permits the correct use of the mechanical strength of the material in accordance with the nature of the forces perceived by the beam elements.

Possible profiles of asbestos cement beams are shown in the firm. For the overlapping device, the beams are laid with flat flooring and the gaps between them are filled with lightweight concrete, connecting them to each other (Fig. 2). The overlap is obtained with a smooth ceiling that does not require plaster.

The fiber cement bearing capacity mainly depends on

on tensile strength of the material: when using sheet asbestos cement with a tensile strength of 200-250 kg / cm, the described beams can be used for intermediate floors with a span of 5-6 m and more. At the same time, the own weight of the beams is 4-5 times smaller compared to thin-walled reinforced concrete beams.

To obtain a beam with an increased bearing capacity, the following construction is proposed.

The upper and lower flanges of the beam are made of two or three interconnected layers of sheet asbestos cement in such a way that the number of layers by the middle of the span is greatest and by the ends of the beam is reduced in accordance with the distribution of stresses in the shelves along the length of the beam. Elements of the beam walls are also formed from two to three layers of joined sheets, with one layer in the middle of the span, and by the end of the beam: the number of layers increases in accordance with p, height H, and to the shear and main stresses in the beam walls (Fig .7).

It is proposed to build the layers in the walls from that place along the length of the beam, where the thickness of the shelves decreases to the corresponding layer so that in any section of the beam the sum of the number of layers in the shelf and in the wall remains the same. As can be seen from FIG. 8, this provides the flat surface of the flanges of the beam and simplifies the molding process, as well as the possibility of producing the beam from sheets that are drab in length.

The asbestos cement beams of the types described are advisable to be made from raw sheets, immediately after removing them from the carpet webs: such sheets, as is well known, are easily formed and are well connected to each other when pressed.

The forming of beams can be effected, for example, by the method of hydraulic pressing, for which

a simple fixture (Fig. 9) is required, consisting of a detachable box U, 2, 3, enclosing the beam from the outside, and a chamber with perforated walls. 4, covered with a thin rubber case 5 and the corresponding outline of the internal cavity of the beam.

Asbestos cement sheets are laid at the bottom of the crate / forming the bottom shelf of the beam. On the edges of chamber 4, raw sheets forming the walls of the beam are formed. The surfaces of the raw sheets to be joined are lightly brushed with metal brushes and moistened with cement milk. The chamber 4 with the sheets laid on its faces is placed on the bottom of the /, then the side walls of crate 2 are installed. 2. The sheets forming the upper flange of the beam are spread over the chamber, then the cover 3 is installed and the crate is firmly screwed. Water is pumped into the internal cavity of chamber 4, which expands the rubber cover 5 and with increasing force presses on the raw asbestos cement sheets, pressing in beams of the required shape and interconnecting the sheets forming the flanges and walls of the beam. After being held under pressure to achieve some strength, the product is released from the mold and sent to the hardening chamber.

The described beams can be used to perform interfloor and attic floors, flat roofing, warm gable roofs with puffs, etc.

Their advantages are s lightness, fire resistance, resistance to corrosion, elimination of metal consumption, ease of manufacture, and ease of installation.

Subject invention

A composite beam is made of sheet of asbestos cement or similar material, the walls of which are made of bent sheets, and the web is composed of several layered

each other flat sheets are placed on those sections of the beam where the thickness of a different length, differing by the shelves is reduced by one or

the fact that the walls of the beam are also co-several sheets, the thickness of the walls

stacked from several layered-increased by the same amount

sheets of different lengths, and sheets.

-3M

FIG. four

FIG. 3

   L7 VII

FIG. 6

FIG. five

FIG. eight