SU989010A1 - Glued wooden beam - Google Patents

Description

(5) GLUED WOODEN BEAM The invention relates to construction and is intended for the manufacture of bending bearing elements. A wooden beam is known for glued, including horizontal plates in the package, between which adhesive layers and reinforcing elements of the support zones, made in the form of plates, having a variable length, are reduced, are reduced to the ends of the beam} This design is characterized by insufficient bearing capacity and strength of the beam and the difficulty of making veneer plates. The closest technical solution to the present invention is a glued wooden beam, including horizontally arranged plates arranged in a package, between which adhesive layers and reinforcing elements of the support areas are placed, in the form of linings attached to the lateral faces of the beam with the direction of fibers. lining perpendicular to the fibers of the beam 2. The disadvantage of this beam is that the wood shrinks across the fibers of the supporting parts of the beam significantly more shrinkage of reinforcement elements attached to the lateral surface perpendicular to the fibers of the beam, which leads to a breakdown of the joint, accompanied by a decrease in the bearing capacity of the beam along the tangent the stresses that are determining in the evaluation of the carrier are capable of (the beam as a whole. The aim of the invention is to increase the bearing capacity and strength of the beam for chipping. This goal is achieved by the fact that in a glued wooden beam, including horizontally placed plates arranged in a package, between which are placed adhesive layers and reinforcing elements of the support areas attached to the side edges

beams, reinforcement elements are made in the form of corrugated sheets, with horizontal perforated sections, each of which is placed between the plates in the adhesive layer.

Figure 1 shows the beam, side view (fragment; figure 2 - section aa in figure 1.

The glued wooden beam includes plates 1, horizontally laid one above the other in a package, adhesive layers 2, reinforcement elements 3 of the support areas. The reinforcement elements are made in the form of corrugated sheets with horizontal perforated sections k, the ends of which 5 are fixed to the beam itself on the glue .

The choice of reinforcement elements 3 characterized by a significantly larger modulus of elasticity of the second kind in comparison with wood leads to the fact that a significant part of the tangential stresses arising when loading a glued wooden beam is transmitted to the corrugated sheet, and this reduces the tangential stresses transmitted to the wood support sites.

The reinforcement of the support zone is provided by attaching the corrugated sheets to the side edges of the glued beam by gluing them with wood in the glued interlayers between the beam boards and in the marginal zones along the upper and lower planes of the beams. Moreover, the attachment of a corrugated sheet in the midpoint of the height of the beam is made more often in order to intensify the operation of the sheet against the effect of tangential stresses. Corrugated sheets are perforated in the contact zone with wood for better gluing.

The presence of corrugations does not interfere with the defoaming of temperature, shrinkage and swelling of wood and does not cause undesirable stresses in the structure.

However, the joint work of the corrugated sheet and the beam, characterized by the condition of compatibility deformation of

Td j ga

leads to a significant redistribution of tangential stresses equal in a corrugated sheet

G- A GA

where St.- tangential stress in the wood beams;

GA shear module in wood;

Q. - shear modulus of the material of the corrugated sheet.

If we assume a corrugated sheet of metal with a SCD of 850–10 kg / cm, the modulus of elasticity of wood is assumed to be GA U kg / cm, and the tangential stresses in the wood; limit the calculated resistance to chipping {; 12 kg / cm, the tangential stresses in the sheet are t

Rckq /

ii in Oh L

- / o2o / cn

GA-to Thus, the attachment of a corrugated sheet, the material of which, compared to wood, has a significantly greater value of the modulus of elasticity of the second kind, contributes to an increase in the shear forces perceived by the cross section and an increase in the bearing capacity of the beam along the transverse force.

Claims (2)

1. USSR author's certificate number 808627, cl. E 0 B 5/12, 1979. 2. USSR author's certificate If, cl. E O B 5/12. FIG. g