RU2204672C2 - Supporting structure for power transmission line - Google Patents

Abstract

FIELD: construction industry, supporting structures in the form of space truss for power transmission lines. SUBSTANCE: supporting structure for power transmission line presents space framework of polygonal cross-section that includes at least three shaped chords positioned at some distance one from another and interjoined by members of grids with formation of closed lateral outline. Each shaped chord is made of trihedral metal continuous sheet bent in transversal plane over entire height of supporting structure with formation of central surface and bent surfaces forming stiffening ribs of chord and placed at obtuse angle with it. Members of grids are made fast to extreme stiffening ribs of adjacent chords. Central surface of chord comes in the form of isosceles triangle or trapezium and each stiffening rib bordering on central surface of chord along two of its sides has shape of isosceles or right-angled triangle or trapezium. Base of each triangle or larger base of each trapezium is located in base of framework. EFFECT: reduced usage of steel for manufacture of chords, optimized form of chord by height of framework to withstand loads acting on framework, reduced weight of structure of polyhedral metal narrow-base support resting upon single foundation. 2 cl, 7 dwg

Description

 The invention relates to the field of construction, in particular to supporting structures in the form of a spatial truss for a high voltage power line (power transmission line).

 For the most frequently used and more reliable free-standing supports (without guy wires), the forces in the strut belts are determined mainly by bending moments from the loads, which in normal conditions are directed perpendicular to the axis of the high voltage line, and in emergency modes, they are directed along the axis of the high voltage line. Since the bending moments in the upper sections are less, and in the lower sections more, the sections are performed with inclined belts in order to possibly bring together the forces in the belts of the upper and lower panels of each section. With the equality of these efforts, it is possible to fully use the strength of the material of the belts over the entire height of the section, which minimizes the cost of steel on the belts. However, the large slope of the belts leads to an expansion of the struts of the supports in the lower part, an increase in the mass of the grate and the need to install supports on three or four foundations.

 To reduce the area occupied by the supporting structures for power lines, the number of foundations and the mass of the lattice, narrow-base supports are currently used, attached to one foundation. When performing the construction of the struts of these supports, similarly to the design of wide-base ones, the forces in the belts increase due to the decrease in the width of the strut, and due to the decrease in the slope of the belts, the forces in the belts of the upper and lower panels of each section differ significantly. Therefore, the strength of the belts selected for maximum efforts (in the lower panels) is not fully used in the other panels of the sections. For these reasons, the steel consumption for belts in narrow-base bearings increases significantly.

 The noted drawbacks of narrow-base supports made as broad-base are partially eliminated by the use of narrow-base polyhedral racks from a bent sheet with a continuous cross section in the form of a regular polygon. In order to save material, the cross-sectional dimensions of the multifaceted pillar usually decrease from the maximum in the lower part to the minimum in the upper part in accordance with the reduction of bending moments. Similar designs have found application as typical supports for 110 and 220 kV overhead lines (see the Handbook for High-Voltage Electrical Installations. M: Energoatomizdat, 1989, pp. 425, 426, as well as the Guide to designing the supports for overhead lines and outdoor switchgear of substations with voltage higher than 1 kV. M., Central Institute of Typical Design, 1989, p. 58, 59).

 The disadvantage of the support with a rack of continuous multifaceted section remains a relatively large consumption of material. Since during bending, the stress in the fibers located in the region of the neutral axis of the cross section is much lower than the allowable, i.e. the strength of the material in these fibers is not fully used.

 A support structure is known in the form of a spatial truss of a polygonal cross section for power lines, including shaped belts made of sheet material that forms a rigid profile when bent, and lattice elements attached to them, while the lateral belts of the spatial truss are trihedral of separate solid metal sheets, curved along the entire height of the supporting structure, and includes planes located at an obtuse angle to each other in the form of isosceles triangles in the middle and adjacent to them along the two lateral sides of the rectangles forming the stiffening ribs of the belts, and the planes of the triangle and the rectangles are inclined to the vertical axis of the spatial truss, and the lattice elements are rigidly attached to the extreme stiffening ribs of the adjacent lateral belts and placed with them in the same plane of each side face of the spatial truss while the rectangular stiffeners of adjacent belts are parallel to each other, the ends of the lattice elements of adjacent side faces of the truss are attached to common nodes and its zones, the support structure in the cross section at the base nodes and connections made octagonal sectioned, and the top of the support structure is formed in a quadrangular plane (RU, Application 94020592, E 04 H 12/00, publ. 1996).

 This design of the transmission line support is adopted as a prototype.

 The supporting structure according to this solution has high mechanical strength due to the choice of a rational configuration of the cross section, variable along the entire length of the frameless spatial truss. However, the analysis of the loads acting on the farm by its height shows that in the upper sections the rigidity of the sections is increased and is not fully used. This is determined by the fact that the rectangles, which are stiffeners, have a constant width along the height of the belt and the height of the truss. The dimensions of the stiffeners in the area of the top of the farm are unreasonably large, which leads to increased metal consumption and weighting of the farm. In this regard, it is advisable to develop ways to reduce the consumption of metal sheet going to stiffeners in areas that do not require a strong excess of stiffness under existing loads.

 The present invention is aimed at solving the technical problem of optimizing the consumption of a metal sheet by choosing a rational configuration not only of a cross section variable along the entire length of a frameless spatial truss, but also of configurations of the shapes of the surfaces of the zones.

 The technical result achieved in this case is to reduce the consumption of steel in the manufacture of belts and optimize the shape of the belts along the height of the truss in accordance with the loads acting on the height of the truss to facilitate the construction of a multifaceted metal narrow-base support, based on one foundation.

 The specified technical result is achieved by the fact that in the supporting structure for the power line, which is a spatial truss of a polygonal cross section, containing at least three figured belts located at a distance from each other and interconnected by lattice elements with the formation of a closed transverse contour, each figured belt is made trihedral of a continuous metal sheet, curved in the transverse plane along the entire height of the supporting structure with the formation of a given g the geometrical shape of the central surface and the bent surfaces located at an obtuse angle to it, forming the stiffening ribs of the belt and made of a given geometric shape, the planes of these belt surfaces are inclined to the vertical axis of the spatial truss, and the lattice elements are rigidly attached to the extreme stiffening ribs of adjacent belts and are placed with them in the same plane of each side face of the spatial truss, while the stiffeners of adjacent belts are parallel to each other, the ends of the ele the lattices of adjacent lateral faces of the farm are attached to common nodes on its belts, the central surface of the belt is made in the form of an isosceles triangle or trapezoid.

 With this design of the middle part of the belt, each of the belt stiffness adjoining the central surface of the belt along its two lateral sides can be made in the form of a rectangle or an isosceles or rectangular triangle or trapezoid, while the base of each triangle or the larger base of each trapezoid is located at the base farms.

 In the cross section at the base and the nodes of the sectional connection, the truss is octagonal, and the top of the supporting structure is quadrangular in plan.

 To increase the stability of the supporting structure and simplify its installation, the surfaces of two adjacent trihedral belts and the adjacent side face of the truss and the surfaces of two other oppositely located trihedral belts and the adjacent side face are made from one solid sheet material of a shaped profile.

 These distinguishing features are new in comparison with the known analogues and, together, are necessary to achieve a new technical result, which consists in creating a lightweight quick-mount support structure for a high voltage power line, which has increased stability and mechanical strength in normal and emergency conditions.

The essential features of this supporting structure in the form of a spatial truss are:
- trihedral design of spatial truss belts with solid planes in the form of geometric figures from a seamless sheet metal sheet;
- oblique placement to the vertical axis of the spatial truss with the formation of a cross section of the truss in the shape of a quadrangle;
- placement of stiffening ribs of the belts in the planes of the side faces as parts of its surface formed by the elements of the lattice;
- the implementation of two pairs of opposite belts and adjacent side faces with solid surfaces made of monolithic combined figured sheets.

 - the execution of the central surface of the belt in the form of an isosceles triangle or trapezoid and the execution of each of the stiffening ribs adjacent to the central surface of the belt along its two sides, in the form of a rectangle or an isosceles or rectangular triangle or trapezoid with the location of the base of each triangle or the larger base of each trapezoid in the base of the farm.

The invention is illustrated by drawings, where
figure 1 shows a General view of the spatial truss supporting structure with four belts, the first example of execution;
in FIG. 2 is a general view of a spatial truss with two pairs of aligned belts, a second embodiment;
in FIG. 3 is a general view of the belt supporting structure, the first example of execution;
in FIG. 4 is a General view of the belt supporting structure, a second example of execution;
in FIG. 5 is a General view of the belt supporting structure, a third example of execution;
in FIG. 6 is a general view of a belt of a supporting structure, a fourth embodiment;
in FIG. 7 is a General view of the belt supporting structure, the fifth example of execution.

 According to the invention, the support structure is a spatial truss of a polygonal cross-section for power lines, including figured belts made of curved in the transverse plane of the sheet material and lattice elements attached to them in the form of braces, by means of which these belts are interconnected. The supporting structure of the lattice spatial form with belts of variable cross-sectional length contains at least three curly belts located at a distance from each other and interconnected by braces to form a closed transverse contour.

 Each figured belt is made of triangular metal continuous sheet, bent over the entire height of the supporting structure with the formation of three planes located at an obtuse angle to each other, the first of which being central, made in the form of a given geometric figure (for example, an isosceles triangle, fig. . 1), and the other two, adjacent to the central one on its two lateral sides, are also made in shape in the form of a given geometric shape (for example, rectangles, Fig. 1). In this case, two other planes adjacent to the central one along its two lateral sides form the stiffening ribs of the belt.

 The central surface of the belt can be made in the form of a trapezoid (Fig. 4-6), and each of the stiffening ribs adjacent to the central surface of the belt along its two sides can be made in the form of an isosceles or right triangle (Fig. 6) or trapezoid (Fig. 3, 4). In this case, the base of each triangle or the larger base of each trapezoid should be located at the base of the truss.

 The planes of the surfaces of the trihedral belt are inclined to the vertical axis of the spatial truss, and the lattice elements are rigidly attached to the extreme stiffening ribs of the adjacent belts and placed with them in the same plane of each side face of the spatial truss. The stiffeners of adjacent belts are parallel to each other, the ends of the lattice elements of adjacent side faces of the truss are attached to common nodes on its belts.

 In the cross section at the base and nodes of the sectional connection, the truss is octagonal, and the top of the supporting structure is quadrangular in plan.

 The surfaces of two adjacent trihedral belts and the adjacent lateral face of the truss and the surfaces of two other oppositely located trihedral belts and the adjacent lateral face can be made combined from one continuous sheet material of a shaped profile, as shown in FIG. 2.

 The following is an example of a specific embodiment of the invention.

 The support structure for the power transmission line of FIG. 1 is made in the form of a spatial truss, which includes curly corner belts 1 with one, for example, a triangular face 2 and two, for example, rectangular faces 3 and lattice elements in the form of braces 4.

 The spatial truss of the support structure of the power transmission line of FIG. 1 is formed by four curly belts interconnected by lattice elements. Each farm belt 1 is made trihedral of a continuous sheet of thickened rolled metal of a curved cut, curved into three flat geometric shapes in the shape of an isosceles triangle, forming the middle side face 2 of belt 1, and in the form of rectangles forming the two extreme edges 3 of this farm belt.

 Two extreme flat faces 3 are adjacent at an obtuse angle to the flat middle face 2 of belt 1 and perform the function of stiffeners.

 One extreme face 3 of each neighboring belt 1 is placed in the plane of the adjacent lateral face of the truss and is at the same time an integral part of this lateral face over its entire height.

 The elements of the lattices in the form of braces 4 are rigidly overlapped to the inner surfaces of the extreme edges 3 of the adjacent belts 1 and are placed along the entire height of the side faces, and the braces of the 4 adjacent side faces of the truss are joined in the common attachment points of the adjacent belt 1. The lattice elements can be made of corner or round profile.

 The surfaces of two adjacent trihedral zones 1 and the adjacent surface of the side face and, similarly, the surfaces of two opposing zones and the adjacent side face of the truss, can be made of monolithically combined, continuous shaped metal sheets of a thickened profile (Fig. 2). The elements of the gratings are attached to the rectangular faces 3 of these combined belts 1 along only two lateral faces of the truss.

 The trihedral belts 1 and adjacent side faces form a cross section of the spatial truss in the shape of an octagon, and the top of the supporting structure is quadrangular in plan (Fig. 1, 2).

 A triangular belt for a truss, depending on the height of the supporting structure and the calculated loads, can be made with a central surface in the form of an equilateral triangle and stiffeners in the form of trapeziums (Fig. 3) or in the form of equilateral triangles (Fig. 7). The belt in the central part can be made in the form of a trapezoid (Fig. 4-6), on the sides of which there are stiffeners having the shape of a trapezoid (Fig. 4), or rectangles (Fig. 5), or triangles (Fig. 6). The trapezoid in shape may be equilateral.

 Thus, the supporting structure is a spatial truss with at least three trihedral belts and three lattice faces. The cross section of each belt continuously decreases from the lower end to the upper end due to a change in the width of the middle face. Lattice elements can be made from a rolled or bent corner, as well as from a round profile or pipe; fastening to the extreme edges of the belts is possible by welding or bolts.

 The inclination of the axes of the belts and the angle between their faces are selected so that the width of the lattice faces will be constant along the height of the structure, which is convenient for the unification of the elements of the lattice.

 The long support structure can be made for ease of transportation and installation sectionally from composite figuratively bent along the edge of sheet metal strips attached to each other by upper and lower edges, for example, using flange joints built from the inside of them, made of a corner or flat profile, and welding.

 Such a construction of a spatial truss from solid figuredly bent metal sheets with a larger cross-sectional area at the base of the supporting structure than the cross-sectional area at the top of the support, and with an octagonal spatial truss with side faces reinforced with stiffeners 3 and braces 4 having common attachment points on each belt 1, has high mechanical strength to bending and torsional loads when performing multi-chain support of power lines and when one of the phase wires of a high voltage power line breaks.

 At the same time, this design has a small metal consumption and light weight, can be quickly mounted. When assembling the truss of the supporting structure, it is necessary to observe the correct angles of inclination of the side belts to the central vertical axis of the support and the arrangement of the belts relative to each other in the transverse plan. To solve this problem, it is provided that when assembling the supporting structure shown in FIG. 1, 2, the distance between adjacent rectangles of adjacent zones is the same in height of the spatial truss. In this case, the position of the belts relative to each other is easily adjusted, which makes it possible to assemble the truss in accordance with the spatial arrangement of its belts and slopes to the vertical axis of the truss. In this case, braces of various lengths can be used. Perhaps the oriented position of the belts relative to each other when using elements of gratings made in the form of braces of the same length. Since the braces of 4 adjacent lateral faces of the truss are joined in the common attachment points of the adjacent belt, when using braces of the same length when assembling the truss, the spatial belts are laid out in accordance with the specified location relative to each other and taking into account the slopes to the vertical axis of the truss. It is possible to solve the problem of checking the correct spatial position of the elements of the truss combined combination of the same distance between adjacent rectangles of adjacent belts and braces of the same length.

 The stated assembly technique of the supporting structure is applicable to other examples of belt designs.

 The present invention is industrially applicable, since its implementation does not require special technology other than that currently used in the manufacture of truss structures.

Claims (2)

 1. The support structure for the power line, which is a spatial truss of a polygonal cross section, containing at least three curly belts located at a distance from each other and interconnected by lattice elements to form a closed transverse contour, each curly belt is made of trihedral of continuous metal sheet bent in the transverse plane along the entire height of the supporting structure with the formation of a given geometric shape of the central surface and position bent at obtuse angles to it, forming stiffening ribs of a belt and made of a given geometric shape, the planes of these belt surfaces are inclined to the vertical axis of the spatial truss, and lattice elements are rigidly attached to the extreme stiffening ribs of adjacent belts and are placed with them in the same plane of each lateral face of the spatial truss, while the stiffeners of adjacent belts are parallel to each other, the ends of the lattice elements of adjacent lateral faces of the truss attached They are connected to common nodes on its belts, characterized in that the central surface of the belt is made in the form of an isosceles triangle or trapezoid, and each of the stiffening ribs adjacent to the central surface of the belt along its two sides is made in the form of an isosceles or rectangular triangle or trapezoid while the base of each triangle or the larger base of each trapezoid is located at the base of the truss.  2. The supporting structure according to claim 1, characterized in that in the cross section at the base and the nodes of the sectional connection, the truss is octagonal, and the top of the supporting structure is quadrangular in plan.

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