RU2460856C1 - Slab reinforcement joint - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: slab reinforcement joint comprises a slab resting on pillars and a reinforcement bar. A joint of the reinforcement bar arranged in one horizontal plane matches the pillar axis. The joint is made with the help of one or two rings from a section of a steel pipe. Rings are installed inside a pillar to match axes of rings with a pillar axis. For one ring reinforcement ends bent down or up are installed inside this ring. For two rings one part of bent reinforcement bar ends is installed inside one ring, and the other part - inside another ring. Ends of the reinforcement bar are fixed in concrete either with the help of a bent end with a head extruded at the end, or by increasing length of the bent end by a rectilinear vertical section of the bent end.

EFFECT: simplified manufacturing, installation of a slab, and lower consumption of reinforcement bars.

6 dwg

Description

The invention relates to ceilings of all types of frame buildings, namely monolithic, precast-monolithic, ribbed, flat bezbalkny with capitals and without them.

Known joint support reinforcement of crossbars of prefabricated and precast-monolithic ceilings, made end-to-end by bath welding using an insert of the same profile as the connected fittings (V.N.Baikov, E.E.Sigalov. Reinforced concrete structures. General course. - M .: Stroyizdat, 1991 .-- S.301 and 500). The disadvantage of the junction is the complexity and complexity of the implementation.

It is also known the reinforcement of the support zone of bezel-less flooring with capitals with cross reinforcing meshes, that is, in two layers (V.N. Baykov, E.E.Sigalov. Reinforced concrete structures. General course. - M .: Stroyizdat, 1991. - P.330) . The disadvantage of this reinforcement is the high saturation of the upper zone of the ceiling with reinforcement, which makes it difficult to concreting the ceiling of high quality. In addition, the two-layer arrangement of reinforcing meshes reduces the average value of the estimated height of the cross-section of the floor and increases the consumption of reinforcement. The use of such reinforcement is limited to beam-free ceilings.

The aim of the invention is to ensure the universality of the joint of the ceiling reinforcement, simplifying the manufacture and installation of the ceiling, reducing the consumption of reinforcement.

This goal is achieved by the fact that the joint of the overlap reinforcement is carried out by means of rings from the steel pipe trim installed inside the column with the alignment of the axes of the rings with the axis of the column.

The essence of the invention lies in the fact that the joint of the floor reinforcement located in one horizontal plane coincides with the axis of the column, is made using one or two rings of steel pipe trimming, installed inside the column with the alignment of the axes of the rings with the axis of the column, bent for one ring up or down, the ends of the reinforcement are placed inside this ring, and for two rings, one part of the closed ends of the reinforcement is placed inside one ring, and the other part of the bent ends of the reinforcement is inside the other ring, while the ends rmatury anchored in the concrete either by the folded end with the upset head at the end, or by increasing the length of the folded end due rectilinear vertical portion of the folded end fittings.

Figure 1 shows the location of the reinforcement 1 of the crossbars 3 of two mutually perpendicular directions and the ring 2 from the steel pipe cut, and figure 2 is a section AA of figure 1, the reinforcement 1 is equipped with a landed head 4 at the end of the bent end.

Figure 3 shows a diagram of the junction of the reinforcement 1 of a flat bezel-less overlap 3, and Fig. 4 shows a section B-B of Fig. 3, the reinforcement 1 is joined by two rings 2, the ends of the reinforcement 1 are bent alternately down and up with placement inside both rings, and the end face of the bent end is equipped with a planted head 4.

The joint of the reinforcement 1 of the ceiling 3, located in the same horizontal plane with the center on the axis 6 of the column 5, is carried out with the help of ring 2 from the steel pipe cut placed inside the column with the axis of the ring 2 aligned with the axis 6 of the column 5, and the ends of the reinforcement bent down or up 1 wind up inside the ring 2 and interact with it through concrete. The continuity of the reinforcement 1 of the overlap 3 on the axis 6 of the column 5 is ensured by the fact that the ring 2 perceives the efforts of the entire reinforcement.

The normal direction of the bent ends of the reinforcement 1 is down (figure 2). However, with a large number of fittings 1 (Fig. 3), the bent ends may not fit inside one ring 2, then two rings are installed on the same axis and one part of the bent ends of the fittings 1 is placed inside one ring, and the other part of the bent ends of the fittings 1 is inside another rings (figure 4). At the same time, the arrangement of the bent ends of the reinforcement 1 inside both rings is uniform and symmetrical with respect to the axis of the ring 2 (Figs. 1, 3).

Anchoring of reinforcement 1 in concrete is carried out either by a bent end with a head up at the end (FIGS. 2, 4), or by increasing the length of the bent end due to a straight vertical section.

The diameter of the bend and the length of the bent end of the reinforcement 1, necessary for its anchoring in concrete, is determined by the standards (SP 52-101-2003. Concrete and reinforced concrete structures without prestressing reinforcement - M .: 2004).

The reinforcement 1 of the crossbars 3 is additionally bent in a horizontal plane in the direction of the axis of the ring 2, combined with the axis 6 of the column 5 (figure 1).

The interaction of the bent ends of the reinforcement 1 of the ceiling 3 with the ring 2 through concrete provides the following advantages: versatility - the joint is suitable for all types of ceilings of frame buildings for civil and industrial purposes, namely monolithic, precast-monolithic, ribbed, flat girders with and without capitals; simplicity of the joint due to the minimum number of connecting parts - one or two rings 2 from the steel pipe trim, the absence of welded or bolted joints and the absence of special requirements for the accuracy of manufacture and installation of the ceiling 3; profitability due to the fact that the reinforcement 1 is located in one horizontal plane and provides the maximum value of the calculated cross-sectional height of the ceiling 3.

The proposed device operates as follows.

Figures 5, 6 show the interaction diagrams of reinforcement 1 with concrete and concrete with ring 2. Over the entire length of the seal of reinforcement 1, stretched with a force F _a , there are adhesion stresses τ with concrete, and stresses are added to the curved end of reinforcement 1 crushing σ _p . The upset head 4 at the end of the bent end of the valve 1 experiences a compression stress σ _b . In the absence of a planted head at the end of the bent end of the reinforcement 1, an increase in the length of embedment in concrete is required due to the rectilinear vertical section at the bent end.

These stresses, firstly, hold reinforcement 1 from being pulled out of concrete, and secondly, they are transmitted through concrete to ring 2 in the form of active pressure with intensity σ _a distributed along the trapezoid (Fig. 5). The resultant active pressure σ _a -q _a acts on the ring 2 with an eccentricity e with respect to the center of gravity of the cross section of the ring (Fig. 5) and is distributed uniformly or unevenly around the perimeter of the ring 2 (Fig. 6). In any case, the tensile force F _a in the reinforcement 1 is the resultant of the concrete active pressure σ _a and q _a on the ring 2.

The elastic deformations of ring 2 under the influence of the active pressure of concrete σ _a and q _a will cause a passive rebound of concrete σ _p and q _p , which partially neutralizes the active pressure, that is, unloads ring 2. The passive pressure of concrete σ _p and q _{p is} not recommended to be taken into account when calculating in margin of safety of the ring.

Given the foregoing, the tensile force in ring 2 is equal to (Metal structures: textbook for university students: Ed. Yu.I. Kudishin. - 9th ed. - M: Publishing Center "Academy", 2007. - P.573).

,

,

where n is the number of reinforcement per ring;

ψ is the angle between adjacent reinforcing bars (Fig.6);

F _a = A _s · R _s - force in the reinforcement;

here A _s is the cross-sectional area of the reinforcement;

R _s is the calculated tensile strength of the reinforcement.

The cross-sectional area of the ring is determined by the formula

,

,

where R _y is the calculated tensile strength of the steel pipe;

γ _c is the coefficient of the working conditions of the ring, including, inter alia, the eccentric application of the active pressure q _{a of} concrete on ring 2, should be less than one (SP 53-102-2004. General rules for the design of steel structures. - M .: 2005. )

Thus, the proposed joint of the floor reinforcement is universal, simplifies the manufacture and installation of the floor, and saves the reinforcement.

Claims (1)

The joint of the floor reinforcement, including the ceiling resting on the columns, and the reinforcement, characterized in that the joint of the ceiling reinforcement located in one horizontal plane coincides with the axis of the column, made using one or two rings of steel pipe trim installed inside the column with alignment the axes of the rings with the axis of the column, moreover, for one ring, the ends of the reinforcement bent down or up are placed inside this ring, and for two rings, one part of the bent ends of the reinforcement is placed inside one ring and the other part The elongated ends of the reinforcement are inside another ring, while the ends of the reinforcement are fixed in concrete either with the help of the bent end with the head up on the end, or by increasing the length of the bent end due to the straight vertical section of the bent end of the reinforcement.

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