RU176462U1 - Multi-span carrier beam - Google Patents

Abstract

A multi-span support beam includes a hollow profile (1) of a composite cross section, consisting of two walls (2), an upper belt (3) and a lower belt (4), part of which is filled with concrete (5). The hollow profile (1) is provided at the ends on the extreme supports (6) with transverse support diaphragms (7) and at the intermediate supports (8) in the zone of zero bending moments with transverse intermediate diaphragms (9). The walls (2) in cross section have an arcuate concave inside the hollow profile (1) shape and are connected by tie rods (10) in the area of their contact. Stops (11) are attached to the inner surfaces of the upper belt (3) and the lower belt (4). The technical result is a decrease in the material consumption of a multi-span load-bearing beam, 1 wpp, 8 silt.

Description

The utility model relates to construction, namely to beams of continuous crane overpasses, spans and other elements that work mainly in conditions of spatial bending in the open air.

Known metal continuous beam of rectangular, box-shaped or I-section, including a beam made of rolled or welded profiles, support devices made according to the scheme of articulated bearing or rigid jamming of its ends, while the beam is made of stepwise variable rigidity, and sections with greater bending stiffness located under the plot of bending moments with extreme ordinates (RU 2336397, Е04С 3/00, 10.20.2008).

The disadvantage of this design solution is the increased material consumption of the beam due to the large consumption of steel on the beam elements and the need to install additional elements in some cases to ensure local stability.

A steel-concrete beam is known, including upper and lower zones, walls and supporting diaphragms, forming a closed loop filled with concrete, walls of a curvilinear shape of double curvature, the distance between which decreases from the upper belt to the lower, in the walls there are holes and cutouts that are arranged with a variable pitch along the length of the beam in accordance with the diagram of shear stresses, while the walls are joined by prestressed tie rods (RU 2621247, Е04С 3/07, 06/01/2017).

The disadvantage of this design solution is the increased material consumption of the beam due to the inefficient use of concrete along the span of the beam due to a constant cross section.

The closest technical solution to the claimed one is a multi-span carrier beam, including a hollow profile, part of which is filled with concrete, the beam is equipped with transverse diaphragms installed in the cavity of the beam, at the ends and at intermediate supports, in the zone of zero bending moments, and the ends of the diaphragms are apart towards the compressed and are close to the stretched zones, and in the compressed zones between the diaphragms above the horizontal axis of the beam, plates are installed in its cavity that limit the closed cavity filled with concrete (SU 897993, Е04С 3/00, 1 01/05/1982).

The disadvantage of this design solution is the increased material consumption of the beam due to the irrational use of concrete along the height of the section, since the width of the concrete along the height of the section of the beam remains constant, which does not correspond to the diagram of normal compressive stresses in concrete and leads to an increase in material consumption, the presence of steel diaphragms inside the beam, is small affecting the bearing capacity of the beam, and insufficient adhesion of concrete to the surface of steel elements, because there are no special elements to increase adhesion, which leads to a decrease in the efficiency of the joint work of steel and concrete.

The objective of the utility model is to reduce the material consumption of a multi-span load-bearing beam.

The technical result is achieved by the fact that a multi-span bearing beam, including a hollow profile of two walls, an upper and lower zone, part of which is filled with concrete, transverse diaphragms installed above the extreme supports at the ends of the beam and at intermediate supports in the zone of zero bending moments, has an arcuate concave inside the beam, the cross-sectional shape of the walls, which are connected by tie rods in the zone of their contact, while concrete is located in the upper part of the section along the entire length of the beam, and in the bottom only intermediate supports.

The multi-span support beam may further include stops fixed to the inner surfaces of the upper and lower support belts in the areas of the concrete beam.

The invention is illustrated by drawings, where

- in FIG. 1 - general view of the beam;

- in FIG. 2 - plot of bending moments in the beam from the distributed load;

- in FIG. 3-cross section 1-1;

- in FIG. 4 - cross section 2-2;

- in FIG. 5 - cross section 3-3;

- in FIG. 6 - cross section 4-4;

- in FIG. 7 is a diagram of normal stresses in concrete in a cross section of 1-1;

- in FIG. 8 is a diagram of normal stresses in concrete in a cross section of 3-3.

The multi-span support beam (Fig. 1) includes a hollow profile 1 of a composite cross section, consisting of two walls 2, an upper belt 3 and a lower belt 4, part of which is filled with concrete 5. The hollow profile 1 is provided at the ends above the extreme supports 6 with transverse support diaphragms 7 and at intermediate supports 8 in the zone of zero bending moments (Fig. 2) with transverse intermediate diaphragms 9.

The walls 2 in cross section have an arcuate shape concave inside the hollow profile 1 and are connected by tie rods 10 in the zone of their contact (Figs. 3, 4, 5, 6). Concrete 5 is located in the upper part of the cross-section of the hollow profile 1 along the entire length of the beam and is in a closed circuit formed by the walls 2 of the upper belt and the transverse support diaphragms 7. Concrete 5 is located in the lower part of the cross-section of the hollow profile 1 at the intermediate supports 8, and is closed the contour formed by the walls 2, the lower belt 4 and the transverse intermediate diaphragms 9 (Fig. 5).

Stops 11 are attached to the inner surfaces of the upper belt 3 and the lower belt 4 in the form of bar reinforcement, plates, or corner profiles.

The presence of concrete 5 inside the hollow profile 1 provides local stability of the walls 2 and the compressed sections of the upper belt 3 and lower belt 4 along the entire length of the beam, which leads to a decrease in steel and material consumption of the beam as a whole.

The presence of concrete 5 inside the hollow profile 1 along its entire length ensures the distribution of local pressure from an external load, for example, mobile, which leads to a decrease in the thickness of the walls 2 and, as a result, to a decrease in the material consumption of the beam as a whole.

The distance between the walls 2 decreases from the upper belt 3 and the lower belt 4 to the center of the cross-section of the hollow profile 1, which reduces the volume of concrete 5 in the low-stress part of the beam section (Fig. 7, 8) and, as a result, reduces the consumption of material on the beam as a whole .

The presence of the tie rods 10 ensures the perception by the walls 2 of lateral pressure from concrete 5 and, as a result, eliminates the additional elements of fixing the position of the walls 2 at the stage of manufacture of the beam and during operation, which reduces the consumption of materials.

The outline of the walls 2 of the hollow profile 1 has a curved shape corresponding to the shape of the diagram of normal stresses in concrete 5 of the compressed zone of the cross section of the beam (Fig. 7, 8). The parameters of the outlines of the curved walls 2 are selected in such a way as to ensure equal tension of the concrete in this zone, which makes it possible to fully use its strength properties and, as a result, reduces the material consumption of the beam as a whole.

The outline of the walls 2 of the hollow profile 1 provides good aerodynamic characteristics of the cross section under the action of wind exposure, which leads to a decrease in the material consumption of the beam when used outdoors.

The presence of stops 11 provides effective joint operation of the upper zone 3 and the lower zone 4 with concrete 5 under the action of shear stresses. Stops 11, as intermediate supports, reduce the estimated length of the upper belt 3 and lower belt 4, which leads to increased stability under the action of operational loads and allows to reduce their thickness, as well as reduce the material consumption of the beam as a whole.

The bearing capacity of a multi-span load-bearing beam is ensured by the selection of the class of concrete, steel grades, dimensions of the cross-section of the beam and its elements, the pitch of the stops and tie rods.

Claims (2)

1. A multi-span bearing beam, including a hollow profile of two walls, upper and lower zones, part of which is filled with concrete, transverse diaphragms installed above the extreme supports at the ends of the beam and at intermediate supports in the zone of zero bending moments, characterized in that the walls are transverse sections have an arcuate shape concave inside the beam and are connected by tie rods in the zone of their contact, while concrete is located in the upper part of the section along the entire length of the beam, and in the lower part only at intermediate supports. 2. A multi-span load-bearing beam according to claim 1, characterized in that it contains stops rigidly connected to the inner surfaces of the upper and lower zones on the sections of the beam with concrete.

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