RU2834587C1 - Steel-concrete structure of coating or flooring of building - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to the field of construction, namely to the steel-concrete structure of the coating or ceiling of a building. Steel-concrete structure of the building covering or ceiling includes a steel I-beam with upper compressed and lower stretched flanges and a reinforced concrete slab with upper and lower reinforcement. Upper compressed flange of the steel I-beam is embedded into the concrete slab and is located at the level of its upper reinforcement to ensure joint operation of the steel I-beam and the reinforced concrete slab.

EFFECT: reduction of construction height and increase of its bearing capacity.

1 cl, 3 dwg

Description

The invention relates to the field of construction and can be used as a supporting structure - floors and roofs of buildings, as well as bridge spans.

The following types of composite beams are known: a) - the steel beam and slab are connected with the help of stops; b) - the steel beam is partially encased in concrete and connected with the slab with the help of stops; c) - the steel beam and slab with haunches are connected with the help of stops; d) - the steel beam is partially encased in concrete, precast reinforced concrete slabs rest on the lower chord of the beam through a sheet; d) - the slab is supported on the profiled sheeting on the steel beam (intermediate support of the sheeting), e) - the slab is supported on the profiled sheeting on the partially encased steel beam (extreme support of the sheeting); g) - the steel beam is completely encased in concrete; h) - the reinforced concrete slab is supported on the lower chord of the beam, stops are on the beam flange; i) - support of the reinforced concrete slab on the lower chord of the beam, stops on the beam wall [SP 266.1325800.2016. p. 8, Fig. 4.2]

In sections: a, b, c, d, e, z, i, to ensure joint operation of the steel beam and reinforced concrete slab, stops are used, during calculations in most cases it is impossible to place a sufficient number of stops to ensure joint operation, because of this the bearing capacity of the elements is lost. In sections: g, e, w, d, the beams are concreted, which leads to additional costs for the implementation of the structure. In section: d, permanent formwork is used, which also leads to additional costs, since it cannot be reused, unlike, for example, panel formwork.

A well-known steel-reinforced concrete beam made of a welded I-beam, on which a reinforced concrete slab rests, the joint work is ensured by a mesh, which is located in the body of the slab and welded to the upper shelf of the I-beam. [Patent No. 2706982. MPKE04C 3/294, Bulletin No. 33, dated 21.11.2019].

The disadvantage of this solution is to ensure the joint operation of the beam and the plate, ensuring the quality of welding of the elements.

A known composite beam, or more precisely a butt joint of a steel beam and a reinforced concrete slab, comprising stops welded to the beam and embedded in the body of the slab in the form of continuous steel strips with slots and rod reinforcement located in the slots. The slots are elongated, forming a comb, with an inclination in the direction of the main stresses in the concrete of the slab at an angle to the vertical equal to 10-60 ^o . The rod reinforcement located in the slots forms the lower working reinforcement mesh of the reinforced concrete slab. [Patent No. 2110639. MPKE01D12/00, dated 10.05.1998].

The disadvantage of this solution is the additional costs for installation work and reinforcement material.

The closest to the invention is a composite steel-reinforced concrete structure with a reinforced concrete slab supported on the lower chord of the steel section of an I-beam [STO ARSS 11251254.001-018-4, Guide to the design of composite steel-reinforced concrete structures, Moscow 2018 I.I. Vedyakov, D.V. Kanin, S.B. Krylov, p. 1, Fig. 1.2, b].

The disadvantage of this solution is that the reinforced concrete slab is completely in the tension zone, as is known, concrete does not work effectively in this zone and is not taken into account in the calculation. Due to the fact that the concrete is stretched, cracks are formed in it (with significant opening), and it can reach that the crack is formed along the entire height of the slab section, which leads to a loss of rigidity, to significant deflections, which adversely affects the psychological and aesthetic perception of this floor. In this case, significant (calculated) reinforcement of the slab is required to absorb the forces, and the upper shelf of the steel I-beam is in the compressed zone and a problem with loss of stability arises.

The purpose of the invention is to save material, reduce the construction height of the section, and increase the bearing capacity of the section.

To achieve the set goal, the section is designed in the form that the upper compressed shelf of the steel I-beam is embedded at the level of the upper (structural) reinforcement of the reinforced concrete slab, the lower (structural) reinforcement is necessary only to perceive internal forces in the concrete and prevent chipping, the joint operation of the steel beam and the concrete slab is ensured by embedding the upper shelf of the steel I-beam in the concrete slab, friction between steel and concrete, that is, adhesion of materials, the lower shelf of the steel I-beam is completely in the tension zone, and the section does not have problems with loss of stability, while embedding the upper shelf of the steel I-beam at the level of the upper reinforcement allows to reduce the construction height of the section.

Fig. 1 shows a cross-section of a steel-reinforced concrete structure. Fig. 2 shows a steel-reinforced concrete structure along a section. Fig. 3 shows a top view.

The reinforced concrete structure consists of a steel I-beam (pos. 1), concrete (pos. 2), lower (structural) reinforcement of the concrete slab (pos. 3), and upper (structural) reinforcement of the concrete slab (pos. 4).

The manufacture of this structure is carried out as follows. A steel I-beam 1 is installed at the design elevation, then the panel formwork is set up, the (structural) upper 4 and lower 3 reinforcement of the concrete slab is installed, and then concrete 2 is supplied. Upon reaching the specified strength, the formwork of the steel-concrete beam element is removed.

This solution will allow saving (on materials and installation works) on connecting elements that ensure joint operation of the steel beam and concrete slab. It is expected to increase the bearing capacity by 20-25%.

Claims (1)

A reinforced concrete structure of a building roof or ceiling, including a steel I-beam with upper compressed and lower tension flanges and a reinforced concrete slab with upper and lower reinforcement, characterized in that the upper compressed flange of the steel I-beam is embedded in the concrete slab and is located at the level of its upper reinforcement to ensure the joint operation of the steel I-beam and the reinforced concrete slab.