RU2728058C2 - Prestressed composite wooden beam - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to beams of floors and coatings of buildings. Prestressed compound wooden beam includes a glued pack of boards, a monolithic insert, anchor rods and longitudinal prestressed rods. Monolithic insert with height not less than the height of the compressed section of the beam is taken with a design resistance exceeding the similar parameter of wood by three or more times, to the suction end of which is supported with the possibility of rotation in the middle of the plate from the spring material through the deformed lining, and to the ends of the plate prestressed rods are connected.

EFFECT: technical result is higher strength.

1 cl, 4 dwg

Description

The invention relates to the field of construction and can be used as floor beams of residential and public buildings.

Known wooden beam, which includes a glued package of boards, clips at the ends of the beam, prestressed reinforcement (see a / s USSR No. 339649, E04C 3/18, 1970, publ. In bull. No. 17, 05.24.1972).

The disadvantages of a prestressed wooden beam are: laboriousness of manufacture, low efficiency of prestressing. First you need to make the cage beams with the wire reinforcement, the casing for the wire reinforcement, then mount the cages with the reinforcement and the casing. Longitudinal prestressed rods located in the lower zone of the beam cross-section are used ineffectively, the beam has a low bearing capacity.

Known is a wooden prestressed beam including a beam with flexible reinforcement fixed on it and a tension device in the form of tie bolts (see French patent No. 2046397 21/00, 1970).

The disadvantages of a wooden prestressed beam are the difficulty of adjusting the stress in the reinforcement, the complexity of the tensioning devices.

The closest is a prestressed wooden beam, which includes a glued package of boards, clips at the ends of the beam, and prestressed reinforcement (see USSR aircraft box No. 1244259 E04 3/18, published in bulletin No. 26 of 07.15.1986).

The disadvantages of a prestressed wooden beam are: weak bearing capacity of the compressed zone of the beam, the fasteners of the prestressed flexible rods are bulky, weak bearing capacity of the support zone of the beam due to its weakening by a bulky de-relaxation tensioning assembly.

The invention is aimed at increasing the overall bearing capacity of a wooden beam by strengthening the compressed zone, maintaining the support zone of the beam while increasing the effect of prestressing from the longitudinal rods.

The result is achieved by the fact that in a wooden beam, including a glued package of boards, a monolithic liner having longitudinal prestressed reinforcing bars, according to the invention, plates with a deformable spacer and made of a springy material are installed in the end part of the beam, to which the ends of the longitudinal reinforcing bars are fixed, while the plate in its middle rests on the tapered end of the liner.

The result is also achieved by the fact that the insert is made of monolithic wood plastic or polymer concrete and is connected to the beam layers by means of anchors located with a variable pitch, and the longitudinal rods are prestressed along the arc of their sagging, the curvature of which is provided by horizontal rods placed along the envelope of the moment diagram.

FIG. 1 shows a prestressed composite wooden beam, consisting of a package of boards, transverse plates, an insert, anchors and branches of prestressed rods; in fig. 2 is a top view of a composite wooden beam; in fig. 3, 4 - sections A-A, B-B beams (Fig. 1).

The prestressed composite wooden beam includes a package of boards 1, vertical anchors 3, transverse rods 4, branches of longitudinal rods 5 and 6, a monolithic insert 2, plates 7. Transverse rods 4 are placed along the envelope of the moment diagram. At the ends of the branches of the longitudinal rods 5 and 6, a thread is cut for nuts 8, plates 7 of springy material with a lining are placed 9. On the plates 7, holes are made for the branches of the longitudinal reinforcing rods 5 and 6, through which they are tightened with a nut 8.

In the factory, first, boards with pre-marked holes for longitudinal reinforcing bars 5 and 6 are prepared, boards 1 are glued, holes are made and transverse rods 4 are inserted on the glue. Threads are cut at the ends of the branches of rods 5 and 6, longitudinal bars 5 and 6 are passed through holes of a package of boards 1. On the transverse end plates 7 of a springy material (for example, steel, textolite), holes are made under the branches of the longitudinal rods 5 and 6, the transverse plates 7 are put on the branches of the rods 5 and 6 from both ends of the beam tensioners - nuts 8. After preparatory procedures produce a monolithic insert with wood plastic (Fig. 1) or fiber-reinforced concrete, polymer concrete. Then, after acquiring a monolithic liner of the hosted strength, the flexible longitudinal rods 5 and 6 are pulled, creating a prestressing nut 8 (Fig. 1).

The support of the end plate 7 in its middle on the tapered ends of the insert 2 and the presence of a deformable lining 9 ensures the equalization of the prestressing forces in the branches of the reinforcement 5, 6. The springiness of the material of the plate 7 gives de-relaxation properties to the tensioning unit.

The creation of prestressing of the branches of longitudinal flexible reinforcement and the presence of an insert increases the rigidity and bearing capacity of a composite wooden beam, along normal and inclined sections, due to the location of the longitudinal reinforcement along the arc of its sagging and the use of a plate with de-relaxation properties.

The assembled prestressed composite wood beam has increased rigidity, load-bearing capacity and reliability, as well as reduced material consumption.

Claims (2)

1. A prestressed composite wooden beam, including a glued package of boards, a monolithic liner, anchor rods and longitudinal prestressed rods, characterized in that a monolithic liner with a height not less than the height of the compressed zone of the beam section is adopted with a design resistance exceeding the same parameter of wood by three or more times, to the narrowed end of which a plate of springy material is supported with the possibility of rotation in its middle through a deformable lining, and prestressed rods are attached to the ends of the plate. 2. A prestressed composite wooden beam according to claim 1, characterized in that the transverse rods are placed along the envelope of the moment diagram, and the insert is connected to the package of boards by vertical anchors located with a variable pitch decreasing to the beam supports.

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