RU155717U1 - REINFORCED CONCRETE LOWER BELT - Google Patents

Abstract

Reinforced concrete crossbar of reduced height, including the crossbar body with lower horizontal shelves reinforced with C-shaped grids, embedded parts, prestressed wire reinforcement installed in the lower and upper parts of the crossbar body, reinforcing cages with transverse reinforcement and the reinforcing mesh located in the upper part of the body crossbars installed on supporting sections of the crossbar body, characterized in that in the lower part of the crossbar on supporting sections an additional reinforcing mesh is installed, forming with reinforcing the mesh is a closed clamp, while the reinforcing meshes are made identical, consisting of longitudinal straight reinforcing bars connected to bent reinforcing bars and located at an equal distance from each other.

Description

Application area

The utility model relates to the field of construction and can be used as a supporting crossbar of the extreme span when supporting floor slabs on one side or as a crossbar of intermediate spans when bilaterally supporting floor slabs, but with an uneven load on the sides of the crossbar (with the appearance of torque) for construction multi-storey buildings with a frame communication system and articulated coupling of a crossbar with a column.

State of the art

Known two-shelf reinforced concrete crossbar (Series 1.020-1 / 87 "Structures of interspecific use for multi-storey public buildings, industrial and auxiliary buildings of industrial enterprises", issue 3-1 "Crossbars 450 mm high for supporting multi-hollow floor slabs", developed by TsNIIEP TBZ I TK and TSNIIPROMZDANIY, approved by the USSR GOSSTROY, protocol No. A4 dated 12.12.90), in which the side edges of the crossbar are made with slopes and it is reinforced with bar reinforcement with or without prestressing. The height of the crossbar is 450 mm.

The disadvantages of the known technical solutions are low operational properties, high material consumption and low installation speed at the construction site. The disadvantages are due to the fact that the crossbar has a too high section height and a large height of shelves, which limits its use in the construction of residential and public buildings. In addition, the design of the crossbar provides for the presence of a reinforced concrete console in the column, which increases the complexity of manufacturing the column.

A known construction of a reinforced concrete crossbar, (Patent RU 52887 U1 IPC E04C 3/20 publ. 04/27/2006), which includes a lower shelf, longitudinal and transverse reinforcement of the crossbar and lower shelf. The transverse reinforcement of the lower shelf is made in the form of upper and lower transverse reinforcement. The upper transverse reinforcement of the lower shelf is made in the form of straight reinforcing bars located above the lower longitudinal reinforcement of the reinforced concrete crossbar, and the lower transverse reinforcement of the lower shelf is made with a bend and is directed upwards. The upper and lower transverse reinforcement of the lower shelf are located with a certain step, and the transverse upper reinforcement of the lower shelf is inserted into the body of the reinforced concrete crossbar beyond the edge of the lower shelf. The transverse reinforcement is made in the form of trapezoidal clamps, the bolt contains through transverse holes for the passage of the connecting rods laid in the interplate seams of the plates. The lateral surface of the crossbar is made with a bevel, the end section of the crossbar contains a embedded part.

The disadvantages of the known technical solutions are the increased complexity of the flooring device due to the need to install reinforcing bars in the transverse openings of the crossbar and place them in the seams between the floor slabs, while the transverse openings in the crossbar must coincide with the location of the joints between the floor slabs, which limits the range (sizes) applied plates. The reduction in the area of the compressed zone of the cross-section of the crossbar due to the presence of bevels on the lateral surface of the crossbar leads to a decrease in its bearing capacity. The transverse reinforcement of the crossbar in the form of closed trapezoidal clamps significantly reduces the manufacturability of the crossbar.

A known construction of a reinforced concrete crossbar (Patent RU 132465 U1 IPC E04C 3/20 publ. September 20, 2013), selected by us as a prototype, which includes a crossbar body, lower horizontal shelves protruding left and right relative to the crossbar body, transverse reinforcement and longitudinal body reinforcement crossbar and lower shelves, embedded part forming a mounting gap. The lateral surfaces of the crossbar body are made obliquely with respect to the vertical plane and round recesses are made along the lateral surfaces of the crossbar body, the lower shelves are reinforced with bent C-shaped grids formed by straight longitudinal and transverse reinforcing bars. In the upper and lower parts of the cross-section of the crossbar, wire pre-stressed reinforcement is installed and an anti-shrink mesh is located on the lower edge of the crossbar. On supporting parts at a distance from the support equal to L / 4, where L is the span of the crossbar, reinforcing frames with transverse reinforcement are installed.

The disadvantage of this technical solution is the limited use under unilateral or bilateral loading with a predominance of the load on one of the sides (shelves) of the crossbar, that is, when torque appears.

Utility Model Essence

The technical task is to develop a crossbar of reduced height with reinforced reinforcement of the support parts with high operational properties.

The technical result of the utility model is to increase the bearing capacity due to the increased resistance to torsion forces.

The technical result is achieved in that in a reinforced concrete crossbar with a reduced height, including a crossbar body with lower horizontal shelves reinforced with C-shaped grids, embedded parts, prestressed wire reinforcement installed in the lower and upper parts of the crossbar body, reinforcing cages with transverse reinforcement and the reinforcing mesh located in the upper part of the crossbar body installed on the supporting sections of the crossbar body, according to the proposed solution, in the lower part of the crossbar on the supporting sections installed additional reinforcing mesh, forming a closed collar with the reinforcing mesh, while the reinforcing mesh is made identical, consisting of longitudinal straight reinforcing bars connected to bent reinforcing bars and located at equal distance from each other.

Brief Description of the Drawings

The utility model is illustrated by drawings, where:

in FIG. 1 shows a general view of a two-flange reinforced concrete crossbar of reduced height (for supporting floor slabs on both sides of the crossbar and using it in intermediate spans);

in FIG. 2 shows a cross-section in the supporting part of the body of a two-shelf reinforced concrete crossbar;

in FIG. 3 shows the upper and lower C-shaped grids, which, when assembled, form a closed clamp for reinforcing the supporting parts of a single-deck and two-shelf crossbars;

in FIG. 4 shows a general view of a single-deck reinforced concrete crossbar of reduced height (for supporting floor slabs on one side of the crossbar and using it in extreme spans);

in FIG. 5 shows a cross section in the supporting part of the body of a single-deck reinforced concrete crossbar.

Utility Model Implementation

The reinforced concrete crossbar consists of the body of the crossbar 1, which includes the lower horizontal shelf 2.

The end sections of the body of the crossbar 1 are made with a embedded part 3 forming a mounting gap 4 directed downward and at the end of the crossbar. The upper part of the embedded part 3 has a through hole 5, intended for fixing the bolt with wedges and monopolizing the junction of the bolt with the column. On the lateral surface of the crossbar body 1, round recesses 6 are made to a depth of 20 mm, which are arranged with a step of 300 mm along the lateral surface of the crossbar body 1. Two mounting loops 7 are fixed along the longitudinal axis of the crossbar. In the lower and upper parts of the body of the crossbar 1, wire pre-stressed reinforcement 8 and 9 is installed. High-strength Bp1400 wire is used as wire pre-stressed reinforcement 8 and 9. The transverse reinforcement of the lower shelves 2 of the body of the crossbar 1 is made of C-shaped grids 10 formed by longitudinal and transverse reinforcing bars. Reinforcing C-shaped grids 10 are anchored by the ends in the body of the crossbar 1. In the lower part of the body of the crossbar 1 an anti-shrink reinforcing mesh 11 is installed.

On the supporting sections of the crossbar at a distance L / 4, where L is the span of the crossbar, reinforcing cages with transverse reinforcement 12 are installed, as well as the upper and lower C-shaped grids 13 and 14, forming a closed clamp. The upper and lower C-shaped reinforcing mesh 13 and 14 consist of longitudinal straight rods 15, which are installed structurally and designed to connect the transverse bent rods 16, installed with a specific step S. The diameter and step S of the rods 16 are determined by calculation.

The implementation in the supporting parts of two C-shaped grids 13 and 14, wound up on both sides in the cross-sectional plane of the crossbar forming a closed clamp, makes it possible to use the crossbar both in intermediate spans with uneven load transfer to the sides (shelves) of the crossbar, and in the extreme spans with one-way load transfer to the crossbar (Fig. 1 and Fig. 4).

It is rational to manufacture the crossbars using the equipment of the Tensiland formworkless molding line, while at the same time from 10 to 25 crossbars can be simultaneously produced in one section, depending on the size of their span.

The production of crossbars is carried out in the following sequence:

- first, the lower C-shaped grids 14 are laid out in the supporting parts of the crossbar;

- decomposed wire upper 8 and lower 9 reinforcement; it is positioned in accordance with the design regulation and pre-tensioned to the design effort;

- under the lower longitudinal prestressed reinforcement 8, an anti-shrink reinforcing mesh 11 is inserted, C-shaped mesh 10 of the transverse reinforcement of the lower shelf 2 of the crossbar body 1 is inserted. For a single-flange crossbar, C-shaped grids are wound on one side relative to the crossbar body 1, for a two-flange crossbar - two sides;

- further in the supporting parts of the crossbar installed frames with transverse reinforcement 12;

- the upper C-shaped mesh 13 is installed in the supporting parts of the crossbar so that with the upper C-shaped mesh it forms a closed clamp;

- embedded parts 3 and mounting loops 7 are installed.

Next, the technological processes of installing the formwork boards, laying and compaction of the concrete mixture are carried out. The set strength of the concrete mixture can occur both in vivo and during heating with Tensiland equipment. In the latter case, the process of curing is significantly accelerated.

The proposed technical solution allows to increase the operational reliability of the reinforced concrete crossbar by reducing the complexity of manufacturing at the plant while increasing the bearing capacity due to the increased resistance to torsion forces.

The reliability of the device is confirmed by numerical calculations of the bearing capacity and a series of tests performed, including laboratory tests of the full-scale structure and full-scale tests in the conditions of the building under construction, which gave a positive result.

Claims (1)

Reinforced concrete crossbar of reduced height, including the crossbar body with lower horizontal shelves, reinforced with C-shaped grids, embedded parts, prestressed wire reinforcement installed in the lower and upper parts of the crossbar body, reinforcing cages with transverse reinforcement and reinforcing mesh located in the upper part of the body crossbars installed on supporting sections of the crossbar body, characterized in that in the lower part of the crossbar on supporting sections an additional reinforcing mesh is installed, forming with reinforcing the mesh is a closed clamp, while the reinforcing meshes are made identical, consisting of longitudinal straight reinforcing bars connected to bent reinforcing bars and located at an equal distance from each other.

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