RU2573889C1 - Triangular grid of rod structures with additional stands and knee braces - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: triangular grid of rod structures including upper compressed and lower stretched belts, braces and stands, is also equipped with additional knee braces. Each of these knee braces by one end is connected to the upper belt, and by the other end - to the stand. Besides, connection angles of the knee braces divide all panels of the upper belt and all stands of the grid into two parts.

EFFECT: reduced labour inputs and structural material consumption.

3 dwg, 2 tbl

Description

The proposed technical solution relates to the field of construction and can be used in the core structures of coatings (floors) of buildings and structures for various purposes.

Rod structures (trusses) are known that support runs of a roof fence or floor beams, to the triangular lattice of which additional racks are often added, allowing, if necessary, to reduce the distance between the nodes. These racks are relatively lightweight, since they work only on local load and do not participate in the transmission of lateral forces to the support. They are also suitable for reducing the estimated length of the compressed belt [1. Metal constructions. In 3 t. T. 1. Elements of structures: Textbook. for builds. Universities / Ed. V.V. Grief. - M .: Higher. school, 2004 .-- S. 419-421, fig. 7.5, c, d; 2. Metal structures: Textbook for students. higher textbook. institutions / Ed. Yu.I. Kudishin. - M.: Publishing Center "Academy", 2007. - S. 263, 268-269, Fig. 9.6, c, d]. The disadvantage of this technical solution is the presence of long compressed rod elements of the belts and lattice, which is accompanied by an additional consumption of structural material to ensure their stability.

Also known are rod structures (trusses) with parallel belts, the triangular lattice of which is equipped with additional racks and half racks. Each of these half-racks at one end is attached to the brace, and the other end to the lower belt, which helps to reduce the consumption of structural material by reducing the estimated length of the diagonal rods of the lattice [G. Becker Farm with parallel belts. - Copyright certificate No. 781293, 11/23/1980, bull. No. 43]. The disadvantage of this technical solution is that the additional half-racks (in contrast to the additional racks) do not work on the local load and perform the functions of the coupling elements only in the plane of the lattice, without affecting the estimated length of the diagonal rods from the plane of the lattice.

The closest technical solution (adopted as a prototype) to the proposed triangular lattice with additional racks and half-braces is a truss lattice, which includes braces and additional racks, as well as half braces and half-racks. Such a lattice is used for off-site application of concentrated loads to the upper belt or, if necessary, to reduce the estimated length of the compressed belt. It is more time-consuming than a triangular lattice, however, as a result of eliminating the work of the compressed belt to bend and reducing its design length, it reduces the consumption of structural material [1. Metal constructions. In 3 t. T. 1. Elements of structures: Textbook. for builds. Universities / Ed. V.V. Grief. - M .: Higher. school., 2004 .-- S. 420-421, fig. 7.6, d; 2. Metal structures: Textbook for students. higher textbook. institutions / Ed. Yu.I. Kudishin. - M.: Publishing Center "Academy", 2007. - S. 264, 269, Fig. 9.7, d]. The disadvantage of the adopted prototype (truss lattice) is a significant number of core elements that differ from each other, their increased total number, which, being the reason for significant busyness, causes additional labor and consumption of structural material.

The technical result of the proposed solution is to reduce the number of core elements of the lattice that differ from each other and their total number, as well as reduce the additional labor and consumption of structural material.

The specified technical result is achieved by the fact that the triangular lattice of the rod structures, in addition to the upper compressed and lower stretched belts, braces and additional racks, is also equipped with additional half braces. Each of these half-bevels is connected at one end to the upper belt, and at the other end to the strut. Moreover, the connecting nodes of the half-braces divide all the panels of the upper belt and all the racks of the lattice into two parts.

The proposed technical solution is quite universal. In it, additional half-braids have a dual functional purpose. Working on local load, they load up relatively light racks of the lattice and together with them do not participate in the transmission of lateral force to the support. At the same time, as connecting elements, they reduce the calculated length of the compressed belt. A similar efficiency in relation to the prototype (truss grid) is achievable as a result of the joint work of additional half-braces and half-racks. It is obvious here that in the proposed lattice both the number of core elements differing from each other and their total number are simultaneously reduced. The versatility of such a solution ensures its use in run-free coatings. It is rational not only in rod structures with parallel belts or trapezoidal outlines, but also in triangular trusses. The latter circumstance is especially noticeable in triangular farms of the Polonso system, as well as, in the terminology of Academician V.G. Shukhov, in rational farms of the 2nd class [Shukhov V.G. Structural mechanics. Selected Works. - M .: Nauka, 1977 .-- S. 71-82, Fig. 6, 8].

The proposed technical solution is illustrated by drawings, where in FIG. 1 shows a diagram of a triangular lattice of a rod structure with parallel belts, additional struts and half struts; in FIG. 2 is a diagram of a bar structure similar to the trusses of the Polonso system; in FIG. 3 is a diagram of a bar structure similar to rational farms of the 2nd class.

The proposed triangular lattice of rod structures includes an upper compressed belt 1, a lower extended belt 2, braces 3, additional racks 4 and half braces 5. At one end, additional half braces 5 are connected to the panels of the upper belt 1, and the other end to additional racks 4. Connecting nodes half-struts 5 divide each of the panels of the upper belt 1 and each of the racks 4 into two parts.

To determine the total number of core elements of the lattice in the proposed technical solution and its prototype, it is advisable to use the tabular form of calculation (table 1), which shows that the decrease in the number of elements is

35/25 = 1.4 times - in a bar structure with parallel belts;

12/8 = 1.5 times - in a bar structure similar to the trusses of the Polonso system;

28/20 = 1.4 times - in a bar structure similar to rational farms of the 2nd class.

In addition, to compare the proposed (new) technical solution with the well-known core object, a core structure (truss) of non-stop coating made of closed bent-welded profiles (pipes) of rectangular cross-section according to GOST R 54157-2010 “Assortment of steel profile pipes for metal structures” was adopted where the lattice was taken:

1. triangular; 2. triangular with additional racks; 3. sprengelny - known solutions;

4. triangular with additional struts and half braces - the proposed solution (table 2).

Moreover, the initial data common to all the options were:

1. truss span l = 20 m, height h = 2 m (h / l = 1/10), angle of inclination of the braces α = 45 °;

2. design load q = 1280 kgf / m;

3. The estimated resistance of the structural material R _y = 2100 kgf / cm ² ;

4. the nodal connections of the lattice rods and belts are made without shapes, taking into account the prevention of punching or pulling out (0.6≤b / B, where b is the width of the cross section of the lattice rod, B is the width of the cross section of the belt);

5. the minimum wall thickness of the rods of the lattice and belts t _min = 3 mm

As can be seen from table 2, in the proposed (new) technical solution, the consumption of structural material (steel) was reduced by 2.8 ... 11.1%.

Claims (1)

A triangular lattice of rod structures with upper compressed and lower stretched belts, braces and additional struts, characterized in that it is equipped with additional half bevels, each of which is connected to the upper belt by one end and the other end by the end, with the half nodes of the connecting nodes sharing all the upper panels belts and all racks of a lattice in two parts.

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