RU2484214C1 - Method to manufacture light arched girder - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: blank from a rolled section, having a solid wall and two parallel shelves, is cut along the wall. Two parts with ledges are created, in which the outer edge has larger size compared to the base. The cut blank is divided into two parts, the produced parts are shifted in the transverse direction. Each ledge of one part is connected to two ledges of the other part. Longitudinal sections of ledge edges consist of three adjacent straight sections. The middle one from the sections is parallel to shelves, and the extreme ones are arranged as the angle to it. One part of the cut blank is prepared in such a way that the shelf is bent convex to the wall. For this purpose V-shaped cuts are arranged in well ledges to the plane of the shelf. Further the shelf is bent to match edges of V-shaped cuts, and these edges are fixed. The other part of the cut blank is prepared in such a way that the shelf is bent concave to the wall. At the same time the ledges of the wall is cut in the middle to the entire height of the wall to the shelf, and cut edges are opened by means of shelf bending. Further an insert is made between these edges and connected by means of welding.

EFFECT: reduced labour intensiveness of manufacturing and assembly.

3 cl, 9 dwg

Description

The invention relates to building structures and can be used for the manufacture of load-bearing structures of arched coatings of industrial and civil buildings, as well as beams with a convex longitudinal axis to create a building lift. The proposed solution is acceptable for the manufacture of hanging structures - hard threads (flat threads with bending stiffness).

The structural form of the arch can be represented as a modification of the frame structure (p. 492, [1]). The known design of continuous arches from straight rolling profiles (triangular arch), with nodes on flange joints and high-strength bolts. However, in such structures, the advantage of arches is significantly reduced - the deviation of the outline of the longitudinal axis of the arch from the shape corresponding to external loads increases - the parabolic shape (figure 1).

Figure 1 shows a triangular arch with rectilinear bar elements. An overlapping span of the structure is indicated by 1. Arrow lifting the arch by 2. 2. The ratio of these layout parameters determines the values of the forces in the rods of the arch (M; N; Q). Cross section of arch rods - rolling I-beams.

Known designs of arches from solid composite I-beams. In sections of such arches, the shelves are connected by a strip of wall. Moreover, the wall, having a curved shape, is cut from a rectilinear strip with a larger width. This method of manufacturing blanks-walls has significant amounts of waste material.

Known designs of continuous arches with a polygonal outline of the longitudinal axis, consisting of three or more rods of a rectilinear shape (figure 2). With an increase in the number of straight sections in the arch, the outline of the longitudinal axis approaches a parabolic shape, but the number of nodes — flange joints — increases. This entails an increase in the complexity of the assembly.

Figure 2 shows the outline of the polygonal arch. The diagram shows the span of the arch with position 1, the boom of lifting with position 2. The schematic position of the straight rods forming the polygonal shape of the arch is shown. Designated assembly joints of straight-line shipping marks.

Known metal arch with varying stiffness of the wall, patent for the invention 2386759, EV 1/32 [2]. The cross section of the arch has an I-beam composite section. The wall is made of a steel strip with radial corrugations located across the strip. Changing the width of the corrugations along the height of the wall turns a rectilinear strip-blank into a shallow arch wall shape. However, radial wall corrugations reduce the longitudinal stiffness of the wall. As a result, the wall does not perceive longitudinal forces in the arch, which reduces the efficiency of the structure as a whole.

The closest is the technical solution described in [3] - and.with. 1231170 "A method of manufacturing lightweight metal beams" (figure 3; 4). This is a method of manufacturing perforated beams from rolling profiles (blanks representing a solid section with a wall and two shelves). In such perforated beams, the height of the cross-section can be increased 1.8 times with respect to the height of the original rolled product, and the area of any cross section does not change - it remains equal to the cross-section of the original rolled product. At the same time, the wall does not have corrugations and is fully included in the work of perceiving longitudinal efforts.

In figure 3 is indicated: 3 - the upper part of the workpiece; 4 - the lower part of the workpiece; 5 - wall of the workpiece; 6 - cut line of the wall of the workpiece.

A method of manufacturing a perforated beam includes cutting the wall of the workpiece in a continuous broken line into two parts. The cutting line consists of longitudinal and transverse sections, longitudinal - parallel to the shelves of the workpiece, transverse - in the form of straight lines, arranged so that protrusions of the wall are formed in the cut parts. Moreover, the longitudinal edges of these protrusions are longer than the width of the base of the protrusion. Next, perform the transverse displacement of the cut parts to the height of the protrusion and produce the connection of each protrusion of one part with two protrusions of the other part (figure 4).

In figure 4 is indicated: 7 - the protrusions of the upper and lower parts of the workpiece.

Possessing advantages for the manufacture of lightweight beams, this method is not acceptable for the manufacture of beams with a curved outline of the longitudinal axis. The disadvantage is that the perforated beam repeats only the rectilinear shape of the workpiece.

The aim of the present invention is to provide a method of manufacturing a perforated beam with a curved outline of the longitudinal axis.

The technical result from the use of the proposed method is to create a structure of a lightweight arch beam of perforated rolling profiles with a curved outline of the longitudinal axis. The cross-sectional height of such beams is much smaller than the cross-sectional height of curved rod trusses, which reduces the laboriousness of manufacturing and installing lightweight arched beams (the number of flange joints of shipping grades decreases).

The technical result is achieved due to the fact that the billet from the rolling profile having a solid wall and two parallel shelves is cut along the wall (along a solid broken line). The workpiece is divided into cut parts. One of the parts is formed with a curved shelf relative to the wall, and the other with a concave shelf relative to the wall. Then an arched beam is formed - these parts are interconnected, while each protrusion of the concave part is connected to two protrusions of the curved part.

Description of the invention

A method of manufacturing a lightweight arch beam, including cutting a workpiece from a rolling profile having a solid wall and two parallel shelves, cut along the wall along a solid broken line. The edges of the cut form a sequence of protrusions with a given step, in which the longitudinal edge has a larger size than the base. The longitudinal edge consists of three segments, while the middle segments are parallel to the shelves, and the extreme ones are made at an angle to them. In this case, the sum of the acute angles between the middle and adjacent extreme segments of the edge is equal to the angle of rotation of the longitudinal axis of the arch beam.

The workpiece is divided into cut parts, one of which is made with a curved shelf relative to the wall, and the other with a concave shelf relative to the wall. At the same time, in the curved part, in the middle of the protrusions, V-shaped cuts are made to the entire height of the wall. Further, in the part with the curved shelf, the shelves are bent at the angle of rotation of the longitudinal axis of the arch beam in the section where the protrusion cutout borders the shelf. Then the edges of the V-shaped cuts are interconnected, forming a curved part of the arched beam. In another part of the workpiece, the protrusions of the wall are cut in the middle, the shelves are bent. The divorced edges of the cut are interconnected by an insert, forming a concave part of the arched beam. Moreover, the bending angles of the shelves can be reinforced with stiffeners, and in the wall, to reduce the concentration of stresses created by bending the shelves, oval holes can be made at these angles (Fig. 5).

Further, each protrusion of the part with a concave shelf is connected to two protrusions of the part with a curved shelf, forming an arched beam. In this case, the formed parts are displaced relative to each other in the transverse direction.

For different types of structures, the relative position of the curved and concave parts relative to each other can vary. So, in the manufacture of arches, the curved side of the workpiece is in the upper part of the workpiece, and the concave side is in the lower part. In the manufacture of hard yarns (type of hanging structures), on the contrary, the curved side of the workpiece is below, and the concave side is in the upper part of the workpiece.

Figure 5 marked: 8 - V-shaped notch protrusions for part of the workpiece with a curved shelf; 9 is a notch in the form of one line from the edge of the wall to the plane of the shelf for part of the workpiece with a concave shelf; 10 - oval holes in the wall; 11 - extreme segments of the longitudinal sections of the edge.

Such a cut line of the initial hire and oval holes in the wall, in the places of bending of the shelves, provide the possibility of reducing the relative deformations of the shelf from bending and limit them to the elastoplastic stage of the material. Shelves, in place of their bend, reinforce with transverse stiffeners (Fig.6). The temperature effect of the welds connecting the ribs with the shelves also produce relaxation of stresses arising from the bending of the shelves.

In Fig.6 indicated: 12 - transverse stiffeners; 13 - sheet inserts.

Let's consider an example of calculation. It is required to make an arch with a span of 30 m, a boom of elevation of 15 m, a perforated cross-section, from an I-beam No. 30B1 with the location of the holes in the wall in a checkerboard pattern. The thickness of the shelf is 0.85 cm. An increase in the height of the section by 1.7 times. Consequently, the height of the protrusion of the wall in the cut blank is 25.5 cm, its calculated length is 75 cm. The outline of the axis describing the nodes of rotation of the axis of the arch beam is circular. Figure 6 schematically shows the bend of the shelf protrusion of the wall of the workpiece. The radius of curvature of the outer plane of the shelf, at the node of its bend, is 25.6 cm. The radius of curvature of the lower plane of this shelf is 24.65 cm, since it decreases by the thickness of the shelf. The dimensions of the oval hole along the axes, at the ends of the lines of transverse incisions, are taken 40 × 20 mm. This hole in Fig. 7 is conventionally shown by filling an oval.

7 shows the bending unit of the shelf 15 of the convex part of the workpiece. An oval hole, the large axis of which determines the length of development of plastic deformations of the shelf when it is bent. A weld line 14 connects the edges of the V-shaped wall cut after bending the shelf and aligning the edges of the wall cut.

The length of the axis of the circular arch is 47.1 m. The circular sector of the arch is 180 °. The angle of the sector of one ledge of the workpiece α:

$$\alpha =\frac{0.75\cdot 180}{47.1}={2.8}^{\circ }.$$

From the diagram (Fig.7) it follows that the deformation of the outer edge of the shelf is defined as the difference between the lengths of the arcs of the outer and inner planes (whose radii are 25.6 cm and 24.65 cm). Conventionally, we believe that the deformation of the shelf from bending is distributed over the length of the oval hole 40 mm. Further, the wall of the hard brand is included in the work and inhibits the development of deformations of the shelf. Define the lengths of the arcs of the outer and inner faces of the shelf when bending (l ₁ = 1.25 cm; l ₂ = 1.2 cm). Relative strain $$\epsilon =\frac{1.25-1.2}{\mathrm{four}}=\mathrm{0.0125,}\to 1.25\%,$$

which corresponds to the area of the yield plate of carbon steel, and much less tensile deformation. The bending angles of the shelves are reinforced with stiffeners, which are attached to the shelves and walls by electric welding. This increases the rigidity of the shelves, and the temperature effect of welding provides relaxation of elastic stresses in these nodes.

A similar circuit has a node in the bend of the lower shelf (Fig. 8). The difference is that the edges of the linear notch of the protrusion of the wall diverge. The diluted notch edges are interconnected by an insert. The insert may be a sheet with stiffeners or other shape, for example, in the form of a deformed tubular element connecting these diluted edges.

In the considered example, the radius of curvature of the convex shelf is 15.25 m, and the longitudinal axis is 15.00 m. The calculated length of each protrusion of the convex part of the workpiece is 0.74 m, and along the axis of the arch beam 0.73 m. Therefore, reducing the length of the lower edge of the protrusion of the convex part of the arch, within one segment, relative to the upper shelf 0.74-0.73 = 0.01 m. But the edge of the protrusion of the lower part of the workpiece with respect to its shelf increases by the same amount. Inaccuracy depends on the ratio of the radii of the upper and lower zones of the arch. In this example, this discrepancy is less than 1 mm, which does not affect the welding technology. A general view of a fragment of an arch beam with a curved shape of the longitudinal axis is shown in the layout (Fig. 9).

In Fig.9 indicated: 16 - welds connecting the cut parts of the workpiece and the notched protrusions of the parts of the workpieces to each other.

Literature

1. Kudishin Yu.I. "Metal constructions". Moscow. AKADEMA. 2006.

2. Rybkin I.S. Patent for invention No. 2386759, publ. 04/20/10.

3. Zhandarov M.A. A.s. 12231170. "A method of manufacturing lightweight metal beams." BI No. 18 of 05.15.86.

Claims (3)

1. A method of manufacturing a lightweight arch beam, which consists in the fact that the workpiece from a rolling profile having a solid wall and two parallel shelves is cut along this wall into two parts with the formation of protrusions, in which the outer edge has a larger size than the base, then divide cut the workpiece into two parts, displace the obtained parts in the transverse direction and connect each protrusion of one part with two protrusions of the other part, characterized in that the longitudinal sections of the edges of the protrusions consist of three adjacent straight lines segments, the middle of which is parallel to the shelves, and the extremes are made at an angle to it; one part of the cut workpiece is prepared in such a way that the shelf is curved relative to the wall, for this purpose, V-shaped cuts are made in the wall protrusions to the plane of the shelf, then the shelf is bent to align the edges of the V-shaped cuts and fasten these edges; the other part of the cut billet is prepared in such a way that the shelf is concave relative to the wall, while the protrusions of the wall are cut in the middle to the entire height of the wall to the shelf and part the edges of the cut by bending the shelf, then insert and connect between these edges by welding. 2. The method according to claim 1, characterized in that on the walls under / above the shelves in the places of bending of the shelves perform oval holes. 3. The method according to claim 1, characterized in that in the places of bending the shelves are reinforced with stiffeners.

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