SU1754374A1 - Method for manufacturing of lightened metal beam - Google Patents

Description

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The invention relates to the construction, in particular to the manufacture of rigid structural elements or components of building structures, for example, to the manufacture of prestressed beams.

A known method of making a lightweight metal beam involves cutting the beam wall along a zigzag line with the height increasing from the beam ends to its middle, obtained by cutting the protrusions, placing the obtained parts one above the other with a contact in the middle part. mc above the tops of the protrusions on the bottom, while one of the halves is shortened by 1D (pitch) of the period of the zigzag line; bend the halves towards each other until the projections touch each other in an overlap and weld the halves along the projections in an overlap.

The disadvantage of this method is that it does not implement in its entirety the strength properties of the material and

Vi ate

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 constructions, it is laborious and non-technical about: ..-:.; ... . . .-- The closest of the known methods is the method of manufacturing a lightweight metal beam, according to which, in order to increase the bearing capacity of the beam wall in the supporting parts, after cutting the original beam along the vertical wall along a sinusoid in the span, the horizontal section above the neutral axis of the beam and, last in the priporny parts, obtained by the polo on the wall of the initial beam 1 in the flight part of it, draw a cutting line 2 parallel to the beam axis, placing it above the neutral axis of the beam. In the span of the beam, two zones 3 and ht are formed, and the chants of the original beam are connected with a reliable cross-section in the zone adjacent to the bottom of the beam nj from the middle of the beam;

overlapping protrusions of the cut halves

The disadvantage of this method of manufacturing a lightweight beam is the inability to fully realize the strength properties of the material.

The aim of the invention is to increase the bearing capacity of the beam by increasing the completeness of the use of the strength properties of the material due to the creation of pre-stress in the beam of the beam, opposite in sign to the stress from the operational loads, and

Fig. 1 shows an initial beam (with a cut line applied; Fig. 2 — a manufactured beam of the proposed construction

The fabrication of an epoxy metal beam is carried out as follows ,,.,

On the wall of the source beam 1, in the span part of it, cut line 2 is parallel to the beam axis, placing it above the neutral axis of the beam. After cutting, two zones 3 and ht form in the span of the beam, with a cross section in the zone adjacent to the bottom pj su get more

powerful than the cross-section 3, while closing to the top of the cus. After cutting the wall of the beam,

For example, using hydraulic jacks, elastic bending of zones 3 and k to the side of the neutral axis of the original beam 10. The amount of bending of zones 3 and 1 is determined by calculation based on the condition

so that the maximum stresses in the outermost fibers of the zone with weaker cross-section do not exceed the elastic limit of the material of the initial beam “After giving zones 3 and h the corresponding

also, the simplification of the technology and the reduction of 30 folds of them are unfixed in the deformation-labor intensity of manufacturing

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In the state of the spacers 5, welding them to the walls of zones 3 and 7, the spacers 5 can be located at different angles to the beam axis to increase the bearing capacity of the beam by maximally using the strength properties of the material reached along the Main directions. EFFICIENCY Geometric values of reverse sign on the stress, arising from operating loads in the sam beam, by elastic deformation of the upper and lower - 40 ow beams in the span, azrezannoy in the transit portion of the wall of my gf parallel to the neutral axis of the beam; and ;; located in the last fig and recorded by owls in the elastically deformed state; welded to the middle K; between by themselves ": Simplification of tech-.lrgy; and a reduction in labor intensity is achieved by the fact that: cutting the .block by .-. the wall is drawn in a straight line, which is 50 ba, in zone 3 tensile stresses occur, which simplifies the marking of the line; strain and labor-force, and in zone 1. - compressive forces,

resulting from the mutual resistance to the convergence of the support., the beam sections with elastic bending of zones 3 and ka When an operating load is applied, the beams in the sections produce normal stresses - compressive at the top and tension, - at the bottom, t „EU for example-:

the characteristics of the cross sections of the struts 5 should ensure their strength and stability

The resulting beam is prestressed

In a static relationship, the resulting beam works as follows

In the case of mutual elastic bending of zones 3 and k, bending moments appear in them, while tensile stresses appear in the span of these holes in the span, and compressive stresses appear in parts of the walls. in case of elastic, the curvature decreases, t „к0, the length of the cutting line is significantly less than the length of the cut .- .; .- ... along a zigzag-like line, the exclusion of a beam on each other and in their welding. The current beam is cut only in the span, in the adjacent portions of the walls; is not cut

In the state of the spacers 5, weld them to the walls of zones 3 and 7, while the struts 5 can be located at different angles to the beam axis, as far as possible along the directions of the main pressure, in zone 3, tensile forces occur, and in zone 1 - compressive forces

along the directions of the main force of force. The values of geometrical weights, in zone 3, tensile forces occur, and in zone 1. - compressive forces

the characteristics of the cross sections of the struts 5 should ensure their strength and stability

The resulting beam is prestressed

In a static relationship, the resulting beam works as follows

In the case of mutual elastic bending of zones 3 and k, bending moments appear in them, while tensile stresses appear in the span of these holes in the span, and compressive stresses appear in parts of the walls. with elastic curves, the opposite in sign stresses are from elastic deformation of zones 3 and 4 "This leads to a significant decrease in total stresses

Example, It is required to determine the total stresses in a beam of the proposed construction loaded with a distributed load, intensity q 10 t / m. Beam span 10 m, end support - hinged. The initial beam is a wide-flange I-50UJ3 with the following geometrical characteristics: cross-sectional area A 17

The max has the following values 4.33 Ph 3.46-105 kg-cm; M 3.09 Pb 2.47.-1oV-CM; N 1.24 P 2480 kg; NUi -1,2

ten

CM2

moment

sixteen

inertia 1X 74190 moment of resistance Ґх 3030 cm5; radius of inertia ix 489.8 mm0 Material - steel grade according to that 1 -1-3023-81 ru 3500 kg / cm 2 “The initial beam is cut along a line parallel to its longitudinal axis located 100 mm0 above the neutral axis Both zones 3 The upper and lower 4 is given an elastic bend with a maximum distance of 25 (the boom of the bend) between the edges of the cut wall equal to 200 mm. For this purpose it is sufficient to apply between the upper 3 and lower 4 zones cut along the beam wall a concentrated spreading force P 2 , 0 tons in the middle of the span Geometric characteristics / cross sections ba Loki proposed design (in the middle of the span):

IK 159501 cm - ball-inertia moment

points of the proposed construction; U g- 1,24

 2480 kgv Here, h is the distance between the neutral cross sections of the upper and the zones0 Total stresses 600 kg / cmg; About and 2000 kg / s (G 246 kg / cm; 1160

From the loading of the beam with an operational load, the normal nap will be (without taking into account the prestress — 2110 kg / cm2; SGV% 2210 kg; the total normal stress is equal to: (5Н 2357 к (jg b 1byu kg / cm With these catches in the sections of the initial BA No. 50ShZ maximum normal marriages are equal: Gn - + 3300 kg /

Thus, the total (stresses of the operational load of the pre-stress) of the stress in the stressed section of the beam of the former construction is less than the stress of the operational load) in the beam in the upper cross section by 51% of the cross section by 29% „

The proposed beam has a high load-carrying capacity compared to the original beam, it is technological in manufacturing

3

moment of resistance top

4733 cm

her shelves made beams; WfЈ

 4518 moment: the inertia of the lower 4 ",, prya" a,, .n

zones 1NE 8802 cm; the moment of resistance to the part of the beam and cutting of the stack, o

no shelf bottom zone w

of

1300 bottom

cm3;

moment of resistance of the wall of the zone W 301 cm; the cross-sectional area of the lower k of the zone Aiz is 103 cm

As a result of elastic bending of the upper 45th and lower 4 zones in their mid-span sections, normal stresses from bending moment and longitudinal force appeared. The latter were found by calculating the resulting beam as a statically indeterminable system using the method of forces. Bending moments and longitudinal forces in top and bottom of 50

Claims (1)

Invention Formula A method of making a lighter metal beam, including a cutting line mark on the wall due to the fact that, from above the carrying capacity of the base, in order to create the reverse voltage beams in the reverse beam voltage from the operating load, simplify the technology and not labor-intensive manufacturing, the beams cut straight, parallel to the beam axis, and after cutting having obtained the upper and lower sa, they are elastically rescued and fixed in an elastically deflected state, welded between the struts themselves. Max have the following meanings: Mch 4.33 Ph 3.46-105 kg-cm; Me 3.09 Pb 2.47.-1oV-CM; N3 1.24 P 2480 kg; NUi -1 P 0 6 0 5 0  1.24  2480 kgv Here h o is taken, m is the distance between the neutral axes of the cross sections of the upper and lower zones 0 The total stresses are 600 kg / cmg; O and 2000 kg / cm2; (G 246 kg / cm; 1160 kg / cmg0 From loading the beam with an operational load, the normal stresses will be (without taking into account the prestressing) C "y - 2110 kg / cm2; SGv% 2210 kg / cm2, and the total normal stresses are equal: (5H 2357 kg / cm2; (jg b 1bY kg / cm) Under the same conditions, in the sections of the initial beam No. 50Sh3 the maximum normal stresses are equal: Gn - + 3300 kg / cm g Thus, the total (from the action of the operating load and from the prestress) stress in the most stressed section of the beam of the proposed design is less than the stress (on the operational load) in the original beam in the upper half of the cross by 51% and in the lower of the cross by 29% „ The proposed beam has a rather high bearing capacity compared to the original beam, is simple and easy to manufacture. es  „,, vom„ a,, .n -DO parts of the beam and cutting stekki, o „ 45 50 Invention Formula A method of manufacturing a lightweight metal beam, comprising marking the cutting line on the wall of the span t in order to increase the bearing capacity of the beam by creating preliminary voltages in reverse of the axle beam, opposite in sign from the operational loads, simplifying the technology and reducing the labor intensity of manufacture, the beam wall is cut straight, parallel to the beam axis, and after cutting, the resulting upper and lower sa are elastically deformed and fixed in an elastic-deformed state, welded between the spacers themselves. .one Fi.g four