RU116526U1 - NODE FITTLE-FREE CONNECTION OF TUBULAR FARM ELEMENTS - Google Patents

Abstract

A nodal endless connection of tubular elements of a truss, consisting of a belt and rigidly attached bars of a lattice of a rectangular section with through cuts at the points of abutment to the belt, completely repeating the geometry of this junction, characterized in that the belt is made of pentagonal section with one horizontal, two vertical and two inclined walls, and the diagonals of the cross-sections of the lattice rods are located in the axial plane of the truss, while the connection of each of the lattice rods with the belt is carried out along its inclined walls and an edge between them, which, together with the diagonal edges of the lattice rods adjacent to it, is also located in the axial plane farms.

Description

The alleged invention relates to the field of construction and can be used in load-bearing structures of coatings of buildings and structures, for example in roof trusses and roof trusses or trellised girders.

Known sleeveless joints with the direct adjoining of the lattice rods to the belts are known and most rational in tubular farms (1. Metal structures. 3 volts. 1. Construction elements: Textbook for universities / Edited by V.V. Gorev. - M .: Higher school, 2001. - P.459, 462, Fig. 7.26, a; 7.28, a; 2. Metal structures: Textbook for universities / Edited by Yu.I. Kudishin. - M.: Academy, 2007 - S.292, 295, Fig. 9.24, 9.27). Here, in order to avoid bursting, the diameter of the lattice pipe should not be less than 0.3 of the diameter of the belt pipe. In farms of rectangular pipes, this restriction is doubled stricter, that is, the width of the lattice rod should be taken at least 0.6 of the transverse size of the belt.

The disadvantage of the described nodes is the noted limitation, the consideration of which leads to an increase in the consumption of material on the rods and increase the metal consumption of the structure.

Also known are nodular non-shaped connections of tubular trusses in which the belts at the points of contact of the rods are reinforced. So, farms of run-free coatings have been developed where wedge-shaped inserts are provided at all nodes of the upper zone, the lower edges of which are parallel to the lower zone (Trofimov V.I., Kaminsky AM Light metal structures of buildings and structures: Textbook. - M.: Publishing House DIA, 2002. - P.100, Fig. 3.6, c). The installation of wedge-shaped inserts-gaskets reinforces the belt shelf and ensures equality of contact angles to the belts of all braces. However, such inserts increase the complexity of manufacturing and assembling the structure.

The closest technical solution is the nodular non-fit connection of the tubular elements of the truss (options), in which the diagonal cross-section of a rectangular (square) belt is located in the axial plane of the truss, and the braces at the junction have a through cut-out (V-shaped), which repeats the geometry of this adjacencies. According to another embodiment, the belt has a triangular section. In both cases, the connection of each of the lattice elements with the belt is carried out along two adjacent walls. Moreover, the nodal connection may additionally contain a corner profile, which is an overlay located between the belt and the lattice elements (1. Sokolov A.A., Logachev K.I., Zinkova V.A. Numerical studies of the stress-strain state of nodular non-shaped joints of tubular elements farm - Industrial and civil construction, 2007, No. 8. - P.40-41; 2. Zinkova VA, Sokolov AA Nodular non-block connection of tubular elements of the farm (options) / BSTU named after V.G. Shukhov. - Patent for the invention №2329361. - 07.20.2008).

A disadvantage of the known prototype unit is the complexity of its application in farms without running coatings, since the edge of the belt can crush sheets of profiled flooring. In run-through coatings, the very edge of the belt can be wrinkled by run, therefore, it is necessary to arrange support tables for run-throughs, which negatively affects the material consumption of structures and increases the complexity of their manufacture and installation. The implementation of the tubular element of the belt of triangular section also reduces the technical and economic characteristics of the structure, since the sharp corners of the profile increase the stress concentration and expand the metal hardening zones. In addition, the corner pads between the elements of the lattice and the belt in both versions of the known prototype site contribute to the growth of material consumption of the structure, the complexity of their manufacture and installation.

The technical result of the proposed invention is to increase the bearing capacity, reliability and rigidity of the nodular non-shaped joints of the tubular elements of the truss by reducing the concentration of stresses and the volume of welding in the node, as well as simplifying its design and reducing the material consumption, the complexity of manufacturing and installation.

The specified technical result is achieved by the fact that in the nodal, non-facetted connection of the tubular elements of the truss, consisting of a belt and rods of a rectangular cross-section lattice rigidly attached to it with through cutouts at the points of contact with the belt, completely repeating the geometry of this abutment, the belt is made of a pentagonal section with one horizontal, two vertical and two inclined walls, and the diagonals of the cross sections of the rods of the lattice are located in the axial plane of the truss, with the connection of each of the rods of the lattice with a belt is carried out along its inclined walls and an edge between them, which, together with the diagonal edges of the lattice rods adjacent directly to it, are also located in the axial plane of the truss.

The proposed nodular sleeveless connection of the tubular elements of the truss has a fairly universal technical solution. So, for example, with the same effect it can be used in tubular trusses with rhombic or triangular section belts. In this case, two factors favorably affect the increase in bearing capacity, reliability and rigidity of the node compared to the prototype. The first of them is that the connection of the lattice rods with the belt is carried out not only along their adjacent walls, but also along the ribs between them. Here, the rhombic shape of the welds helps to reduce stress concentration, similar to how it occurs in joints with rhombic type overlays (Metal structures. 3 volt. 1. Structural elements: Textbook for high schools / Edited by V.V. Gorev. - M.: Higher School, 2001. - P.169, Fig. 4.25, b).

The second factor is to increase the vertical and horizontal dimensions of the cross sections of the lattice. This size increase for square rods is times and makes it possible to use them in blockless assemblies, when the width of the brace does not exceed 0.6 the width of the belt of rectangular cross section. So, in steel trusses of the Molodechno type, with spans of 24 and 30 m, the width of the belts is 140 mm (0.6 × 140 = 84 mm), and the minimum width of the lattice rods in frameless assemblies is 100 mm (Steel structures of the coatings of industrial buildings with spans 18, 24, 30 m using closed bent-welded rectangular sections of the Molodechno type. Series 1.460.3-14. KM drawing. Sheets 36, 37.1, 37.2). If the group of lightly loaded lattice rods with a section of 100 × 100 mm is replaced by a section of 80 × 80 mm, developed with a diagonal in the axial plane of the truss ( mm), it is possible to reduce the consumption of structural material. In addition, there are no cutouts for abutment, and the processing of the ends of the lattice rods is limited to a flat cut, which also positively affects the technical and economic characteristics of the structure.

As another example of the use of the proposed nodal connection of tubular truss elements, one can cite the options for replacing rectangular lattice rods with equivalent pentagonal cross-section rods with larger dimensions (Pentagonal closed bent-welded profile / A.S. Marutyan, T.L. Kobalia, S.A. Glukhov, G.M. Yanukyan, Yu.I., Pavlenko. - Application No. 20091477247/03 (067318), 12/18/2009). In particular, the already mentioned rectangular (square) section of 80 × 80 mm can be replaced by a pentagonal section of 90 × 96.4 mm. Such an increase in the cross-sectional dimensions of the lattice rods protects the wall of the rectangular belt in a blockless assembly from bursting under compression and pulling out under tension, and also provides welds with the necessary length for calculation, which generally increases the reliability of the nodal joint.

The alleged invention is illustrated by graphic materials, where figure 1 shows the proposed nodular sleeveless connection of the tubular elements of the farm with the upper belt of rectangular cross section, side view; figure 2 is a section aa in figure 1; figure 3 is a section bB in figure 1; figure 4 - the proposed nodal non-shaped connection of the tubular elements of the farm with the lower belt of rectangular cross-section, side view; figure 5 is a section bb in figure 4; figure 6 - the proposed nodular, non-shaped connection of the tubular elements of the farm with the lower belt of the rhombic section, side view; Fig.7 is a section DD in Fig.6; on Fig - the proposed nodular non-shaped connection of the tubular elements of the farm with the lower belt of a triangular section, side view; Fig.9 is a section EE in Fig.8; figure 10 - the proposed nodular non-shaped connection of the tubular elements of the farm with the upper belt of rectangular cross section, side view; figure 11 is a section FJ in figure 10; in Fig.12 - section II in Fig.10; in Fig.13 - the proposed nodular, non-shaped connection of the tubular elements of the farm with the lower belt of square (rectangular) section, side view; on Fig - section KK in Fig.13; on Fig - section LL in Fig.13; in Fig.16 - the proposed nodular non-shaped connection of the tubular elements of the farm with the upper belt of rectangular cross section and the rods of the lattice of a pentagonal section, side view; on Fig - section MM in Fig.16; Fig. 18 is a sectional view. HH in Fig. 16.

The proposed nodular non-shaped connection of the tubular elements of the truss includes an upper belt 1 or lower belt 2 of a pentagonal section with one horizontal, two vertical and two inclined walls, to which are rigidly attached, for example, by welding, the rods of the lattice 3, made in the form of braces or braces and racks (pendants ) In the modified versions of the nodal connection, the upper belt 1 or lower belt 2 can have, in addition to pentagonal sections, rhombic (square with diagonals in the axial plane of the truss), triangular, rectangular, square. Rectangular lattice rods at the points of attachment to the belt have through cutouts that completely repeat the geometry of these junctions and are located relative to their longitudinal axes so that the diagonals of their cross sections are in the axial plane of the truss. The connection of each of the lattice rods with the belt is carried out along its inclined walls and an edge between them, which, together with the diagonal lattice rods adjacent directly to it, are also located in the axial plane of the truss.

In the known prototype unit, due to significant internal efforts in the elements of the truss caused by heavy loads, an additional element in the form of a corner profile can be used, which is an overlay located between the belt and the lattice elements. Under such loads, the proposed nodal connection can remain shapeless, that is, without the use of an additional reinforcing element, since significant internal forces are transmitted and perceived not only by the inclined walls of the lattice and belt rods, but also by the ribs between them, which are thus located in the axial plane of the truss. Here, the absence of an additional reinforcing element indicates a quite sufficient load-bearing capacity of the proposed nodal non-shaped connection, which very favorably affects the material consumption of structures, the complexity of their manufacture and installation.

The location of the diagonals of the cross sections of the rectangular (square) rods of the lattice in the axial plane of the tubular truss during the implementation of the proposed nodal connection expands its scope in comparison with the prototype node and makes its solution more universal, suitable for rhombic belts (6, 7), triangular (Fig. 8, 9) and rectangular (Fig. 10-15) shapes. In the latter case, the efficiency of using rhombic lattice rods increases markedly due to the absence of V-shaped slots in their ends, which makes the design less time-consuming. This implementation of the proposed technical solution predetermines its promise in nodal, non-shaped joints of pentagonal lattice rods with rectangular belts of tubular trusses (Figs. 16-18).

To compare the proposed technical solution with the basic object, the last one was a truss made of closed bent-welded rectangular sections of the Molodechno type FS-30-1.3 with a span of 30 m, a mass of 1984 kg and a design load of 1.3 tf / m (Steel structures of industrial coatings buildings with spans of 18, 24, 30 m with the use of closed bent-welded rectangular sections of the Molodechno type. Series 1.460.3-14. KM drawing. Sheets 37.1, 37.2, 88). The new technical solution is represented by a truss truss with nodular, non-shaped joints of rhombic lattice rods (braces) with a rectangular upper and square lower belts. Rhombic braces are composed of square rods with a section of 80 × 80 mm, the diagonals of which are located in the axial plane of the truss truss. The calculation results are shown in the comparative table, which shows that the consumption of structural material (steel) is reduced by (1842-1785) / (1842 ... 1785) × 100 = 3.1 ... 3.2%.

Table. Steel consumption for bar elements Options Items Cross section mm Length m Quantity Weight kg Note Options Items Section mm Length m Quantity Weight kg Note 1m 1 PC. of all 1m 1 PC. of all Base object IN 1 □ 180 × 140 × 5 30,0 one 24.3 729 729 Upper belt New solution IN 1 □ 180 × 140 × 5 30,0 one 24.3 729 729 Upper belt IN 2 IN 2 OT IN 3 AT 4 AT 4 AT 5 AT 5 H1 □ 140 × 5 27.0 one 21.19 572 572 Lower belt H1 □ 140 × 5 27.0 one 21.19 572 572 Lower belt H2 H2 H3 H3 H4 H4 H5 H5 P1 □ 120 × 4 2.5 four 14.57 36,4 146 Grill rods P1 □ l20 × 4 2.5 four 14.57 36,4 146 Grill rods P2 P2 P3 □ 100 × 3 2.5 16 9.13 22.9 366 P3 □ 100 × 3 2.5 four 9.13 22.8 91 P4 P4 P5 P5 ◇ 80 × 3 2.5 12 7.26 18.2 218 P6 P6 P7 P7 P8 P8 P9 P9 P10 P10 FROM □ 80 × 3 2.0 2 7.26 14.5 29th FROM □ 80 × 3 2.0 2 7.26 14.5 29th Total 1842 Total 1785

Claims (1)

Nodular, non-shaped connection of tubular elements of the truss, consisting of a belt and rods of a rectangular cross-section lattice rigidly attached to it with through cutouts at the points of abutment to the belt, completely repeating the geometry of this abutment, characterized in that the belt is made of a pentagonal section with one horizontal, two vertical and two inclined walls, and the diagonals of the cross sections of the lattice rods are located in the axial plane of the truss, while connecting each of the lattice rods to the belt along its inclined walls and an edge between them, which, together with the diagonal edges of the lattice rods adjacent directly to it, is also located in the axial plane of the truss.