RU2715776C1 - Prestressed reinforced concrete beam - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to the field of construction and can be used as beams of ceilings and coatings of residential and public buildings. Prestressed steel-concrete beam includes steel profiles forming an H-section with ribs in the end part, having anchor elements, longitudinal prestressed reinforcement rods and filling concrete. Between the end and inner ribs there is a rocker made from U-section channel with recess in the middle of the length resting on the lower part of the beam wall. In order to ensure uniformity of forces along the whole length of reinforcement, prestressed reinforcement can be placed in nonmetallic thick-walled tube.

EFFECT: technical result consists in increasing the bearing capacity of the reinforced concrete beam, increasing stiffness, reduction of material consumption.

1 cl, 3 dwg

Description

The invention relates to the field of construction and can be used as floor beams of residential and public buildings.

Known steel pre-stressed beam, including steel I-sections, anchor rods, prestressed flexible reinforcement on both sides of the profile and concrete filling (see utility model patent No. 155802 Е04С 3/294, 2015).

The disadvantage of steel-concrete prestressed beam is the impossibility of a uniform distribution of prestressing forces. This leads to an overload of one branch of the prestressing system relative to the other and reduces both the overall load-bearing capacity of the beam and the reliable operation of the prestressing system.

Known steel-reinforced concrete prestressed beam including steel profiles forming an I-section, anchor rods, prestressed flexible reinforcement, in which angular shorts are mounted at the ends of the steel profile to rotate to regulate the prestressing forces (see Utility Model Patent No. 165473 E04s 3/294, publ. in bulletin No. 29 October 20, 2016).

The disadvantages of steel-reinforced concrete prestressed beams are the weakening of the cross section of the beam wall with a cutout to accommodate the angular shorty, the weak bearing capacity of the supporting zone of the beam due to the absence of supporting ribs.

The closest is a pre-stressed steel concrete beam including steel I-beams having anchor elements, longitudinal reinforcing bars and filling concrete in which several steel plates are mounted in the end part of the beam with the possibility of rotation.

The disadvantages of the prestressed beam are the complexity of the support ribs, the weakening of the alignment of the prestressing forces in the paired reinforcing bars after concreting, the reduction of the prestressing forces in the calculated normal section (as the distance from the end of the beam) determines the bearing capacity of the prestressed beam from the operational load.

The invention is aimed at increasing the overall bearing capacity of a steel-concrete beam by maintaining the alignment of forces in the branches of prestressed reinforcement by placing longitudinal reinforcement in non-metallic thick-walled tubes.

The result is achieved in that in a steel-concrete beam comprising a steel profile of an integral or composite I-section, having longitudinal prestressed reinforcing bars and monolithic concrete, according to the invention, a “beam” of a steel channel of variable section, in which there is a tension unit at both ends, is installed the ends of the longitudinal reinforcing bars are fixed, while in order to center the “beam”, a recess is made in its walls, and the reinforcing bars are enclosed in non-metallic thickness nnye tube. In the end part, a supporting and additional ribs are installed, which are connected to the steel profile of the beam by welding.

In FIG. 1 shows a prestressed steel-concrete beam, consisting of an I-beam profile of a whole or composite section with removed end and side ribs, longitudinal reinforcement and monolithic concrete; in FIG. 2 - view “A” of the end part of the “rocker arm”; in FIG. 3 - a perspective view of the supporting part of the beam in assembled form.

The prestressed steel-concrete beam includes a steel profile 1 and monolithic concrete 2. In the end part of the beam, a fastening unit “5” of reinforcement 3 to the “beam” 4 is installed, in which the ends of the longitudinal reinforcing bars 3 are fixed with a tension unit 5. For centering the rotary “beam” 4, it has recesses in the middle part of the wall 6. For isolation from concrete 2, longitudinal rods 3 are passed through non-metal pipes 7. To strengthen the supporting part of the beam 1, an additional rib 8 is installed within the support, welded to the wall and the shelf Profile 1 is connected to an additional welding rib 9. For the free rotation "rocker" 4 with asymmetric loads between the end of the tube 7 and the "yoke" 4 by a gap "A" 12.

In the factory, first, threads are cut at the ends of the reinforcing bars 3, a rocker 4 is made, holes for the reinforcing bars 3 are made on the ribs 8, the ribs are welded 9. The ends of the longitudinal rods 3, threaded under the nut of the tension unit 4, pass the holes of the ribs through tubes 7 8 and the "rocker" 4 (Fig. 1), put on the nut 5 and tighten the flexible longitudinal rods 3, creating a prestress. After preparatory procedures, monolithic concrete 2 side cavities of the integral (Fig. 1) or composite I-beams are produced. Weld end 10, side rib 11 to the steel profile 1.

This self-regulating execution of prestressing of longitudinal flexible reinforcement allows you to evenly distribute the prestressing forces, eliminates the overload of individual branches under asymmetric operating loads due to the isolation of longitudinal reinforcing bars from contact with concrete, increases the rigidity and overall bearing capacity of the beam and the reliability of the prestressing system, and also reduces the material consumption of the composite beams.

Claims (2)

1. Pre-stressed steel-concrete beam, including steel profiles, forming an I-section with ribs in the end part having anchor elements, longitudinal prestressed reinforcing bars and filling concrete, characterized in that between the end and inner ribs there is a “beam” of a channel of variable cross section with a recess in the middle of the length, resting on the lower part of the beam wall. 2. A prestressed steel-concrete beam according to claim 1, characterized in that in order to ensure uniformity of efforts along the entire length of the reinforcement, the prestressed reinforcement is placed in a non-metallic thick-walled tube.

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