SU1244259A1 - Prestrained wooden beam - Google Patents

Description

The invention relates to construction and is intended for the manufacture of long load-bearing elements of laminated wood, which allow the multi-modular materials to work together.

The purpose of the invention is to increase the bearing capacity of the beam by ensuring the long-term effect of prestressing.

FIG. 1 shows a beam, general view; in Fig. 2, the derelaxation unit at the end of the beam; in fig. 3 shows section A-A in FIG. 2; in fig. 4 is a view along arrow B in FIG. 2; in fig. 5 - times; cut-B-B in FIG. 2

The prestressed wooden beam includes a glued package of 1 plank, a 2-stage yoke, delacation units 3 with an armature 4 installed in the grooves of the beam, forming steps on its ends, between the edges 5 of the yoke 2.

The prestressed wood beam is made as follows.

In the beam, groove 6 for reinforcement 4 is made on the bottom edge of the glued package, and grooves are made at the ends of the beam with the formation of steps on its ends. The armature 4 is passed through the holes of the stop of the collar 2 and is rigidly connected to the anchor. Then the reinforcement is placed in the groove 6 so that the cage tightly covers the end parts of the groove and the ends of the beam, then another holder 2 with de-relaxation node is placed on the opposite end of the beam.

When tensioning an armature through a derelaxation unit 3, for example, in the form of a spring, it is compressed in the recess of the cage formed by the ribs 5. The armature 4 is pulled out.

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and after it is installed on the beam, the latter is compressed by a reactive force from both the stressed reinforcement 4 and the compressed delolaxation unit. In a beam, stresses appear that are opposite in sign to stresses from an external load.

Making grooves along the ends of the beam allows you to construct a stepped-shaped holder, which ensures the redistribution of forces from both the tension reinforcement and the support reaction, which promotes the visibility of wood along and across the fibers.

The cage ribs perform a binding role, since they perceive the bending moment and shear force and provide the redistribution of forces between the upper and lower cage stages and the stability of de-relaxation nodes. The relaxation nodes compensate for the gradual reduction of the initial stresses in the prestressed reinforcement located along the entire length of the beam, and thus provide a long-term effect of prestressing.

In the wooden beam of the proposed construction, an increase in the carrying capacity and flexural rigidity occurs due to the elimination of the prestress losses in the reinforcement. In addition, such a constructive solution of the beam allows to reduce the deformation of the sm of wood from the reactive forces of the stressed reinforcement along the fibers and from the support reaction across the fibers. The construction height of the structure is significantly reduced, as the supporting parts of the beam ensure the stability of the entire beam.

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Claims (1)

A PRELIMINARY TENSIONED WOODEN BEAM, including a glued package of boards, clips installed at the ends at the ends of the beam, and prestressed reinforcement fixed by the ends to the clips, characterized in that, in order to increase the bearing capacity by providing a long-term tensile effect by ensuring the long-term effect of the prestressing , it is equipped with relaxation nodes, each of which is connected to the end of the reinforcement, and the cage is equipped with ribs, while grooves are made in the beam to form a step at its ends, in which between the ribs of the cage are relaxation nodes.