RU172515U1 - PRE-STRESSED STEEL CONCRETE BEAM - Google Patents

Abstract

The utility model relates to the field of construction and can be used as floor beams and coatings of residential and public buildings. The utility model is aimed at increasing the overall bearing capacity of a steel-concrete beam by balancing forces in the branches of prestressed reinforcement and strengthening the structure of its supporting part. A prestressed steel concrete beam includes a steel I-beam of a whole or composite section, monolithic concrete, end plates are welded to the end of the I-beam, forming a support rib, with the possibility of rotation, and an additional rib to strengthen the support zone. To increase the load-bearing capacity and rigidity of the beam before concreting the side cavities of the profile, tensioning devices are placed at the ends of the beam in the form of rotary plates, at the ends of which the ends of the flexible flexible prestressed reinforcing longitudinal rods are fixed with a tensioning unit. The prestressed steel concrete beam made in this way has increased rigidity, load-bearing capacity, provides a reduction in the material consumption of the reinforcement, increases crack resistance, and has increased reliability due to self-regulation of the prestressing of the longitudinal reinforcement and the arrangement of paired supporting ribs in the support zone.

Description

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

A steel beam is known, including a steel I-beam with U-shaped clamps welded to the walls of the profile with longitudinal rods passed under the U-shaped clamps (see Eurocode 4 "Design of steel-reinforced concrete structures", part 1-1, Minsk, 2010, p. 34 , Fig. 6.10 (3)).

The disadvantages of steel-concrete beams are: the complexity of manufacturing a steel-concrete beam with a reinforcing cage. First you need to make a frame consisting of clamps and longitudinal rods, then weld the clamps to the walls. Longitudinal rods located in the upper and lower zones of the beam cross-section are used inefficiently, their area is taken to be a constant section along the entire length along the maximum moment at zero moments at the ends of the beam. In addition, the longitudinal rods are inefficiently used, due to the lack of prestressing, the beam has a high deformability.

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 stress 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.

The closest is a steel-reinforced concrete pre-stressed beam, including steel profiles forming an I-section, anchor rods, prestressed flexible reinforcement, in which angular shorts are mounted in the ends of the steel profile to rotate to regulate the prestressing forces (see utility model patent No. 165473 E04с 3 / 294, published 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 by 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 utility model is aimed at increasing the overall bearing capacity of a steel-concrete beam by strengthening the support zone while maintaining the alignment of forces in the branches of prestressed reinforcement.

The result is achieved in that in a steel-concrete beam, including a steel profile of an integral or composite I-section, having longitudinal prestressed reinforcing bars and monolithic concrete, according to a utility model, steel plates are installed in the end part of the beam, in which the ends of the longitudinal reinforcing bars are fixed at both ends by a tension unit. at the same time, to center the rotary plates that make up the end rib, in the middle part of their length they are welded on the “tacks” to the beam wall. To strengthen the supporting zone of the beam, an ordinary supporting rib is installed in the end part, which is connected to the end edge of the beam by means of welded shorts forming a tubular section.

In FIG. 1 shows a prestressed steel concrete beam, consisting of an I-beam profile of a whole or composite section, longitudinal reinforcement and concrete monolithic; in FIG. 2 - view A of the end of the beam; in FIG. 3 - a node in the upper end of the beam, in FIG. 4 - a perspective view of the supporting part of the beam with attachment points B.

The pre-stressed steel concrete beam includes a steel profile 1 and monolithic concrete 2. At the end of the beam, there is a fastening unit “B” of reinforcement 3, in which the ends of the longitudinal reinforcing bars 3 are fixed with a tension unit 4. tack "7. A fixed plate 6 is electrically welded to the profile wall 1. To strengthen the supporting part of the beam 1, an additional rib 8 is installed within the support, welded by welding 9 to the wall and shelves of profile 1, soy is dined with the end rib by the floor (quarter) of the cylinders 10. In the additional rib 8, open holes 11 are provided for the passage of reinforcement 3.

In the factory, first, threads are cut at the ends of the reinforcing bars 3, holes for the reinforcing bars 3 are made on the plates 5. On the “tacks” 7, the plates 5 are assembled, the plate 6 is welded. The ends of the longitudinal rods 3, threaded under the nut of the tension unit 4, are passed through the holes of the rotary plates 5 (Fig. 2), put on the nut 6 and tighten the flexible longitudinal rods 3, creating a prestress. Install an additional rib 8 with holes 11 and weld 9 to the wall of the profile 1, insert shorts in the form of half cylinders 10 between the ribs and weld them to the plates 5, 6 and 8. Weld the joints 5 and 6 to form the butt supporting rib (Fig. . four). After preparatory procedures, monolithic concrete 2 side cavities of a solid (Fig. 1) or composite I-beams are produced.

Such a self-regulating pre-stressing of longitudinal flexible reinforcement allows evenly distributing prestressing forces, eliminates overloading of individual branches, increases the rigidity and overall load-bearing capacity of the beam and the reliability of the prestressing system.

The assembled prestressed steel concrete beam increases the rigidity, crack resistance, overall bearing capacity and reliability, and also reduces the material consumption of the composite beam.

Claims (2)

1. A prestressed steel concrete beam, including steel profiles forming an I-section, having anchor elements, longitudinal reinforcing bars and filling concrete, characterized in that at the ends of the I-beam there are mounted steel plates supported with the possibility of rotation, forming the end edge of the beam, in which prestressed flexible reinforcing bars are anchored on both ends by a tensioning unit, while for centering the rotary plates in the middle part of their length, they are welded on the “tacks” to the walls ke beams. 2. A prestressed steel concrete beam according to claim 1, characterized in that in order to strengthen the support zone of the beam, an ordinary support rib is installed in the end part, which is connected to the end edge of the beam by means of welded shorts forming a tubular section.

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