JPS59199953A - Reinforcement of piercing hole of beam made of concrete - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for reinforcing through-holes in reinforced concrete or steel-framed reinforced concrete beams.

or .

A through hole is often provided in the abdomen of a concrete beam to allow the ductwork to pass through, but various reinforcement methods have been used in the past to compensate for the decrease in stiffness of the beam due to the provision of the through hole. . For example, as shown in Figs. 1 and 2, a sleeve 4 that forms a through hole is placed on a beam 3 on which main reinforcements 1 and stirrups 2 are arranged, and a sleeve 4 that forms a through hole is placed around the circumference of the beam 3, and horizontal reinforcements 5 and diagonal reinforcement are provided around it. A method of densely arranging reinforcing bars 6 and stirrups 7 and 7' is known, but since the reinforcing bars are complicated and crowded, the reinforcing bar arrangement work is troublesome and time-consuming, and the filling performance of the concrete is also poor. bad. Furthermore, after assembling the reinforcing bar assembly to be dropped into the beam formwork outside the formwork, the reinforcing bars around the planned through-hole location are placed on the vertical and horizontal lines passing through the axis of the through-hole, respectively. After marking, the sleeve was centered according to those markings and temporarily attached to the reinforcing bars, but since the sleeve and surrounding reinforcing bars were far apart, it was difficult to center the sleeve accurately. And it was a hassle.

Another known method for reinforcing through-holes is to use a reinforcing ring in which a large number of rings made of irregularly shaped round bars with different diameters are arranged concentrically, and irregularly shaped round bars extending radially thereon are welded and fixed. There is.

This method consists of positioning and tying a reinforcing ring to stirrups on either side of the intended through-hole axis of the rebar assembly, and inserting a sleeve into the center of the reinforcing ring. Compared to the former method, this method has the advantage that centering can be performed automatically by simply inserting the sleeve into an opening formed in the center of a reinforcing link tied to reinforcing bars. However, since many bar rings arranged concentrically extend radially and are in contact with the bar ring, there are many welding points and the contact area is small, so the strength of the welded part is weak, resulting in The cracks in the concrete around the through hole could not be prevented from expanding.

An object of the present invention is to provide a method for reinforcing through-holes in steel bars or steel-framed reinforced concrete beams, which eliminates the above-mentioned drawbacks and strongly prevents the expansion of cracks in concrete.

In order to achieve the above object, by the method of the present invention, a reinforcing ring formed by fixing a strip material extending radially on a spiral reinforcement made of a bar spirally wound in one plane is attached to the main reinforcement and stirrup. A reinforcing bar assembly including a reinforcing bar assembly is placed at both ends of the planned through-hole axis and tied to the reinforcing bars around the through-hole, and at least two strips are placed in the center of the reinforcing ring through an opening formed at the inner end of the reinforcing ring. , just insert a sleeve to form the through hole.

Hereinafter, embodiments of the method of the present invention will be explained with reference to the drawings.

FIGS. 3 and 4 show a reinforcing ring 10 used in the method of the present invention.
shows. In this embodiment, four strip plates 12 extending radially are placed on a spiral strip 11 which is made by winding a single bar material, that is, a deformed round bar, spirally outward from a point that is sufficiently larger than the diameter of the through hole of the beam. Welded at 900 mm intervals. In this embodiment, in order to support the sleeve 4 forming the through hole, the inner ends of the four strip plates 12 define an opening 13 having a diameter slightly larger than the outer diameter of the sleeve 4. Therefore, if this reinforcing ring 1o is tied to the reinforcing bars on both sides of the planned through-hole axis of the reinforcing bar assembly including the main bar and star lamp, in accordance with the positioning markings made on the reinforcing bars, the sleeve 4 can be tied to the reinforcing ring 10. The sleeve can be automatically centered as soon as it is inserted into the opening 13. In the reinforcing link 10 shown in FIG. 3, the sleeve is received at the inner ends of the four strip plates 12, and the strip plates 12 are arranged at an angle of, for example, 45 degrees, one on each side of the vertical line passing through the center of the reinforcing ring. It is also possible to provide for the sleeve to be received by only at least two strips. However, since the reinforcing ring 10 can be produced in large numbers at a factory, the price is low and the accuracy is uniform.

Figures 5 and 6 show examples of reinforced concrete construction using the method of the present invention. Page 7 shows a state in which the beam reinforcement assembly 8, whose circumference around the through hole is reinforced, is dropped into the beam form 9 and reinforced.

In the through-hole reinforcing method according to the present invention, before the beam reinforcement assembly 8 is dropped and reinforced, a radially extending strip plate 12 is first welded onto the spiral reinforcement 11 spirally wound in one plane. As shown in FIG. 6, the reinforcing ring 10 made of
For example, 14.
15. Bind at 16°17 points. Before bundling, mark the main reinforcement 1 and stirrup 2-18 or 2' at positions on the vertical and horizontal lines passing through the axis of the through hole in advance, and then the reinforcing ring 10 can be placed in the specified position. You can easily take 9 or 1 off. Then, reinforcement ring 10
The sleeve 4 is inserted into an opening 13 formed at the inner end of the strip plate 12 at the center thereof.

In this way, the reinforced beam reinforcement assembly 8 can be dropped and reinforced in the position shown in FIG.

The method of the present invention simplifies the installation of the reinforcing ring compared to the conventional method of arranging reinforcement around the through hole.
In addition, centering of the sleeve is automatically performed, reducing man-hours and therefore costs.

In this embodiment, an integral cylinder was used as the sleeve 4, but in order to avoid any problems with the drop-in reinforcement arrangement, the length of the sleeve 4 was made shorter than the width of the beam by an appropriate length, and each end of the sleeve was The slide sleeve can also be slidably inserted, dropped into the beam formwork 9 and reinforced, and then pulled out and fixed to the formwork.

In the method of the present invention, reinforcing rings placed at both ends of the through hole of the beam are made by welding radially extending strips onto a spiral reinforcement made of a single bar material spirally wound. , Comparing this with a conventional reinforcing ring in which round bars of different diameters are arranged concentrically and a round bar extending radially is attached to the reinforcing ring, firstly, it is a ring made by processing a single bar material into a spiral shape. The invention reliably guarantees strength for a structure in which a large number of concentric rings of different diameters are connected to a bar by welding. Secondly, the strip material radially welded to the spiral reinforcement in the present invention has very little deformation compared to the conventional radial bars and materials welded to the concentric rings, has high yield strength, and is susceptible to cracks in concrete. can strongly prevent the expansion of

[Brief explanation of drawings]

Figure 1 is a cross-sectional view taken along line I-I in Figure 2, and Figure 3 is a cross-sectional view of the concrete beam reinforced by the conventional reinforcement method for through-holes in concrete beams. FIG. 4 is a front view of the reinforcing ring used in the method of the invention, FIG. 4 is a sectional view taken along the line ■-■ in FIG. 3, and FIG. The periphery of the through hole is reinforced by
・This is a cross-sectional view taken along the line ■-■ in Fig. 6, and Fig. 6 is a cross-sectional view taken along the line Vl in Fig. 5. FIG. 3 is a cross-sectional view taken along the line -VI. 1. Main fist muscle 2φ. Star rug 4...
Sleeve 10...Reinforcement ring 110/Spiral reinforcement 12...Strip material 13...Opening 1, f" Figure 1 Figure 2 (6 ■ Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] (1) In a method for reinforcing through-holes in reinforced concrete or steel-framed reinforced concrete beams, a reinforcing ring is used in which a reinforcing ring is formed by fixing radially extending strips onto a spiral bar made of a spirally wound bar in one plane. A predetermined amount of reinforcing bar assembly including main bars and stirrups is placed at both ends of the through-hole axis and tied to the reinforcing bars around the through-hole, and at least two strips are attached at the center of the reinforcing ring by the inner ends. A method characterized in that a sleeve for forming a through hole is inserted into the opening formed by υ.