SU1114762A1 - Method for making prestressed varying-rigidity metal beam - Google Patents

Abstract

METHOD FOR PRODUCING prestressed metal girders PEREMENNrY HARDNESS consisting of two parts adjoining one another, comprising a elastically deformed and the rigid coupling parts beams Mead Him about tlichayuschiys in that, for the purpose povsheni efficiency prestressing and provide rational distribution voltage from external load along the length of the beam, the elastic deformation of parts of the beam is carried out alternately at st, end of variable curvature, the value of which is directly proportional to tional bending moment of the external load and inversely proportional to the flexural rigidity, the elastic deformation of the upper part of the beam is carried out at a lower V installing and tightening attracted thereto.

Description

The invention relates to construction and can be used in the manufacture of prestressed ¹ long-length bearing elements of coatings and floors · buildings, 5 engineering structures, etc.

There is also a known method of manufacturing prestressed composite metal beams, ‘consisting in the fact that prestress 10 in the structure is created by bending one of its constituent elements in the plane of least rigidity and subsequent straightening and attaching to it another tensed element [ij.

The disadvantage of this method is the relatively low efficiency of prestressing, since 20 only one component of the beam is subjected to stress (in the second, stresses are created only by reducing them in the element subjected to bending).

In addition, such a method does not provide constant stresses along the Length; the compressed part of the beam of variable cross section.

The closest technical solution to the invention is the ₃ θ method _of manufacturing a prestressed metal beam, consisting of two components adjacent to one another, including elastic deformation and rigid connection of the beam parts to each other ^ 2j.

Because the flexure beams initial parts produced simultaneously, due to the friction between adjacent portions of the beam at their arching, faktiches- ₄₀ kai prestresses value smaller than the theoretical (since they will be partially work together).

In addition, due to the conventionality ^{45 of the} joint work of two parts of the beam, the known method does not provide an identical distribution of the normal stresses from their preliminary bending and stresses from the bending moment caused by an external load along the length of the beam of variable stiffness. .

The purpose of the invention is to increase the efficiency of preliminary stress Order 6745/21 due to a more complete use of ₍ use of the material of construction and ensuring rational distribution of stresses from external load along the length of the beam.

This goal is achieved by the fact that according to the method of manufacturing a pre-stressed tensile metal beam of variable stiffness, consisting of two components adjacent to one another, including elastic deformation and rigid connection of the beam parts to each other, the elastic deformation of the beam parts <is carried out alternately on the stand of variable curvature , the value of which is directly proportional to the bending moment from the external load and inversely proportional to the rigidity of the structure in bending, and the elastic deformation Contents top of the beam is carried on the lower installation and the attraction thereto.

In FIG. 1 shows a diagram of the prestressing of a beam on a bench.

The sequence of operations for the voltage of a composite beam of variable cross-section is as follows. First, on the stand 1, the supporting parts 2 of which are made with the given radii of curvature, lay the lower part of the beam 3. After installing the power equipment 4, it is bent along the corresponding radii of curvature, for example,. end sections D-8 and C-D and Гj - in the middle section β-C and fix in this position. Then the upper part of the beam 5 is laid on it and the latter is bent. After fixing the upper part 5, the elements of the beam 3 and 5 are connected in a deformed state to each other, for example, by a longitudinal weld.

The indicated method allows one to obtain preliminary (residual) stresses along the length of the structure, equal (or close) in magnitude to the calculated ones and inverse in sign of the stresses from the external load, i.e. to make fuller use of the material. The application of the proposed method for prestressing a beam of variable stiffness compared with the known allows to reduce the material consumption of the beam by 8-15%.

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Branch of the PPP "Patent", Uzhgorod, Project 4,

Claims (1)

METHOD FOR MAKING A PRELIMINARY STRESSED METAL BEAM OF VARIABLE RIGIDITY, consisting of two components adjacent to one another, including elastic deformation and rigid connection of the beam parts between themselves, characterized in that, in order to increase the efficiency of prestressing and ensure rational distribution of stress external load along the length of the beam, the elastic deformation of the parts of the beam is carried out alternately on the stand of variable curvature, the value of which is directly proportional and the bending moment from the external load and inversely proportional to the rigidity of the structure to bend, and the elastic deformation of the upper part of the beam is carried out by installing on the lower and pulling to it. 4 5