JPH03224935A - Reinforcing materials around through-hole of beam section of reinforcement or steel frame/reinforced concrete structure - Google Patents

Abstract

PURPOSE:To promote aseismicity by bending both ends of a horizontal reinforcing steel with a certain inclination, and forming main reinforcing bars having the same lengths of right and left inclined parts and auxiliary bars connecting the main reinforcing bars to each other into two layers in the shape of an approximate octagon. CONSTITUTION:There is a space section 3 having a hole of a beam in the central part thereof, and reinforcing materials are constituted of main reinforcing bars 1 consisting of two bars each in up and down arranged in parallel across the space section 3 and bar-shaped auxiliary bars 2 welded to the main reinforcing bars 1 with them diagonally crossed. After that, the first layer is constituted of the main reinforcing bars 1 of the upper part C1 of the reinforcing materials and the auxiliary bars 2 of the lower part C2 of them, and the second layer is constituted of the auxiliary bars 2 of the upper part C1 and the main reinforcing bars 1 of the lower part C2. All the intersecting points of the main reinforcing bars 1 with the auxiliary bars 2 are connected by means of welding. According to the constitution, strength and aseismicity can be promoted by placing the auxiliary bars diagonally crossed with horizontal parts of the main reinforcing bars on part correspondent in the horizontal direction of the hole.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvements in reinforcing materials around through-holes in beams of reinforcing bars or steel frame/reinforced concrete structures.

[Problems to be solved by conventional technology and invention] Reinforced bars or steel frames
In the beams of reinforced concrete structures, through holes (hereinafter simply referred to as holes) are drilled for air conditioning, water supply and drainage, and power distribution, or the area around the hole must be reinforced because the hole becomes structurally weak. Must be. As a means of reinforcement,
The area around the through hole is reinforced with a wire mesh made of reinforcing bars.

Generally, when reinforcing the area around the beam hole with a wire mesh of reinforcing bars,
From a strength standpoint, it is necessary to place reinforcing bars in a diagonal direction around the hole in order to withstand the shear force that is applied around the hole.In particular, it is necessary to place reinforcing bars in a diagonal direction that is perpendicular to a line that is 45 degrees from the center of the hole. placement is most desirable.

In addition, in terms of construction, if the outer shape of the reinforcing wire mesh is rectangular and has overhanging corners, the corners may get in the way during installation, making it difficult to perform the work, so it is preferable that there are no corners. Furthermore, when considering the wire mesh in the thickness direction, if the reinforcing bars are welded together in three layers (triple layers), when pouring concrete into the reinforcing material, the fluidity of the concrete will be inhibited and the concrete will It has also been found that it is preferable for the wire gauze to be composed of two layers as much as possible since there is a risk that the filling properties of the wire mesh may become insufficient.

Furthermore, experiments have shown that with the conventional method in which reinforcing bars are placed uniformly in the horizontal and diagonal directions of the hole, the strength of the horizontal direction is low, except for some types. It turns out that there may be a shortage.

On the other hand, considering these points and considering conventional reinforcement materials,
For example, in the example of Japanese Patent Publication No. 44-21260,
The reinforcing material is made of two rectangular layers with diagonal reinforcing bars perpendicular to the holes, and is extremely strong.
Since the external shape is rectangular, the corners are protruding, which may make installation difficult.

On the other hand, the method shown in Japanese Patent Publication No. 59-10454 does not have many problems in terms of workability, but because the amount of reinforcing bars in the horizontal direction to the hole is insufficient, this part Inferior in strength.

The present invention was made to improve these problems of the conventional technology, and in terms of strength, it increases the strength of the part horizontal to the hole and improves seismic performance. . In addition, in terms of construction, the reinforcement material is designed to have good workability by eliminating the corners of the rectangle and by making it two layers thick.

[Means for Solving the Problems] The reinforcing material of the present invention for achieving this object is as follows.

That is, the first invention is a reinforcement consisting of a horizontal reinforcing bar that is bent by maintaining a constant inclination angle at both ends, and main bars that have the same angle and length at the left and right inclined parts, and auxiliary bars that connect the main bars. In the upper part of the timber, multiple main reinforcements are placed on the same plane, parallel to each other at regular intervals, and the auxiliary reinforcements in the horizontal part of the main reinforcements cross diagonally with the main reinforcements, and the auxiliary reinforcements cross the horizontal part of the main reinforcements. It consists of an external or almost mouth-shaped shape that is symmetrical from the center line of the part and is placed on the same side as the main reinforcement and connected to the main reinforcement, and the lower part is on the same plane as the auxiliary reinforcement in the upper part. On the side, multiple main reinforcements are arranged on the same plane with their horizontal parts parallel to each other at regular intervals, and the auxiliary reinforcements in the horizontal part of the main reinforcements cross diagonally with the main reinforcements, and the auxiliary reinforcements cross the center line of the horizontal part of the main reinforcements. so that it is symmetrical from
Furthermore, the outer shape of the main reinforcement placed on the same side as the main reinforcement in the upper part and connected to the main reinforcement is approximately mouth-shaped, and the main reinforcement in the upper part and the lower part are inclined parts of each other, or the main reinforcements are inclined. A beam section of a steel or steel/reinforced concrete structure characterized by having vertical extensions from the inclined part of the outermost main reinforcement overlapping and connecting, having an approximately octagonal outer shape, and consisting of two layers. Reinforcement material around the through hole.

Moreover, the second invention is a main reinforcement 10 in which both ends of a horizontal reinforcing bar are bent while maintaining a constant inclination angle, and further, the extended part is bent vertically, so that the angle and length of the left and right inclined parts are the same. -1 and the main reinforcement 10-2 bent in a V-shape, and the horizontal reinforcing bars that connect these main reinforcements, are bent at a constant angle of inclination at both ends, and the angle and length of the left and right inclined parts are the same. In the reinforcing material consisting of the auxiliary reinforcement 20, the upper part has the inverted V-shaped apex of the main reinforcement 10-2 fixed in the center of the horizontal part of the main reinforcement 10-1, and the inclined part of one end of the main reinforcement 10-1. The inclined part of one side of the main reinforcement 10-2 and the main reinforcement 10
The inclined portion of the other end of -1 and the inclined portion of the other side of main reinforcement 10-2 are arranged parallel to each other on the same plane,
The auxiliary reinforcement 20 intersects the main reinforcement 1O-1 and 10-2 on the same side, and the horizontal part of the auxiliary reinforcement 20 and the main reinforcement 10-1 intersect with each other on the same side.
The horizontal parts of are parallel to each other, and the outer shape where the inclined part of the auxiliary reinforcement 20 and the main reinforcement 10-1 are connected is approximately mouth-shaped, and the lower part is on the same side as the auxiliary reinforcement 20 of the upper part, The bottom point of the V-shape of the main reinforcement 10-2 is fixed at the center of the horizontal part of the main reinforcement 10-1, and the inclined part of one end of the main reinforcement 10-1 and the main reinforcement l〇-2
The inclined portion of one side, the inclined portion of the other end of the main reinforcement 10-1, and the inclined portion of the other side of the main reinforcement 10-2 are arranged parallel to each other on the same plane, and the main reinforcement 10 of the upper portion
On the same side as the arch and 10-2, the auxiliary reinforcement 20 is the main reinforcement 10-
1 and 10-2, and the horizontal part of the auxiliary reinforcement 20 and the horizontal part of the main reinforcement 10-1 are parallel to each other, and the external shape where the inclined part of the auxiliary reinforcement 20 and the main reinforcement 10-1 are connected is It has an almost mouth-shaped shape, and the inclined parts of the main reinforcements 10-1 and 10-2 of the upper and lower parts and the vertical extensions from the inclined parts are overlapped and connected, and the outer shape is A reinforcing material around a through-hole in a beam part of a steel or steel/reinforced concrete structure, which is approximately octagonal in shape and consists of two layers.

[Function] As described above, the reinforcing material of the present invention rationally arranges the main reinforcing bars and the auxiliary reinforcing bars, and in terms of strength, the first invention has the following features: For the portion corresponding to the oblique direction of the hole, By arranging the inclined part of the main reinforcement and arranging the horizontal part of the main reinforcement and the auxiliary reinforcement obliquely intersecting the horizontal part of the main reinforcement in the part corresponding to the horizontal direction of the hole, the second invention For the part corresponding to the oblique direction of the hole, the inclined part of main reinforcement l〇-1 and the inclined part of the side of main reinforcement 1O-2 are arranged, and for the part corresponding to the horizontal direction of the hole For,
A horizontal portion of the main reinforcement 10-1, a horizontal portion of the auxiliary reinforcement 20, and
By arranging the sloped part near the top of the inverted V-shape or the bottom of the V-shape of the main reinforcement 10-2, the layer strength is increased,
It has improved seismic performance. On the hζ work surface, good workability can be achieved by eliminating the corners of the square of the reinforcing material and by making it two layers thick.

[Details of the invention] The explanation reinforcement is based on the following ideas.

The horizontal main reinforcement and the diagonal main reinforcement are welded together to avoid creating two layers, and the upper and lower parts of the reinforcement are bent in the desired direction as a single main reinforcement on the same plane. By arranging and using a plurality of reinforcing bars, one layer is formed, and the auxiliary reinforcing bars that connect the main reinforcing bars are arranged on the same side as the main reinforcing bars to form two layers, so that the whole becomes two layers. With this configuration, diagonal bars are placed in the horizontal direction of the hole, and the outer shape is approximately octagonal with rounded corners, and the thickness is such that there is an approximately hexagonal space inside where one beam hole can fit. A reinforcing material in the form of two layers is obtained.

With this configuration, the strength of the horizontal part of the hole is the same, and it has excellent earthquake resistance and ease of construction.

Further, there is an advantage that the manufacturing process is simple and easy to automate.

Hereinafter, for convenience of explanation, the present invention will be described in detail using schematic diagrams.

First, the first invention is as follows.

In FIG. 1, a horizontal reinforcing bar is bent at a constant inclination angle θ1 at both ends, and the left and right inclined portions have the same length and angle as the main reinforcement A. In the upper part C1, a plurality of main reinforcements A (three in the figure) are arranged on the same plane, parallel to each other at regular intervals, and auxiliary reinforcements B are diagonally intersected with main reinforcement A in the horizontal part of main reinforcement A. In addition, main muscle A
The first invention does not necessarily require auxiliary reinforcements that intersect at the inclined portions of the main reinforcements. ), multiple (six in the figure) are placed at appropriate intervals so that they are symmetrical from the center line 2 of the horizontal part of main reinforcement A, and on the same side as main reinforcement A. It consists of a shape in which the intersection points of streaks B are connected by welding (in the figure, the solid line indicates the first layer,
The dotted line indicates the second layer). The upper portion C1 has an approximately mouth-shaped outer shape.

Next, FIG. 2 shows a reinforcing member consisting of an upper portion CI and a lower portion C2 having a shape symmetrical to the upper portion by 180 degrees.

In the lower part C2, on the same side as the auxiliary reinforcements in the upper part, three main reinforcements are arranged in the same plane and parallel to the horizontal part, keeping a constant interval, and the auxiliary reinforcements are placed in the horizontal part of the main reinforcements. An external shape that intersects diagonally with two main reinforcing bars, intersects with four main reinforcing bars at the inclined part of the main reinforcing bars, is symmetrical from the center line of the horizontal part of the main reinforcing bars, and is placed on the same side as the main reinforcing bars in the upper part. has a nearly mouth-shaped shape (in the figure, the solid line indicates the first layer and the dotted line indicates the second layer).

The overlapped intersections of the inclined parts of the main reinforcements A of the upper part C1 and the lower part C2 are connected by welding (or the inclined parts of the main reinforcements of the upper part and the lower part C2) are connected by welding. Vertical extensions from the slanted portions of the outermost main reinforcements are overlapped and connected by welding (not shown).

The reinforcing material has an approximately octagonal outer shape with a hexagonal space in the center for the beam hole, and is made of two layers of reinforcing bars.

In Fig. 1, the angle θ1 of the inclined portion of the main reinforcement A is preferably 45 degrees from the point of view of the shear strength of the reinforcing material.
There is no problem even at 35 to 55 degrees. In addition, it is desirable for the design that the curved point that changes from the horizontal part of the placed main reinforcement to the inclined part is on a straight line connecting the points at the same position of each main reinforcement. On the other hand, the angle θ2 formed by connecting the left and right curved points is preferably 90 degrees, but 60 to 1
There is no problem even at 20 degrees. However, the above θ1. If the angle θ2 is far out of the above range, the length of the reinforcing material becomes too long horizontally or vertically, causing problems.

Next, the auxiliary reinforcements B have the role of connecting the main reinforcements A to each other, improving the adhesion to the concrete, and suppressing the propagation of cracks. This auxiliary reinforcement has the effect of improving seismic performance by compensating for the lack of reinforcement in the horizontal direction of the hole. It is most effective to set the oblique angle to approximately 45 degrees.

In calculating the shear strength of a perforated beam under conventional reinforced concrete calculation standards, as shown in Figure 3, the shear strength of a perforated beam is calculated by applying a 45-degree angle to the center of the hole on the premise of suppressing shear cracks that occur diagonally at an angle of 45 degrees to the center of the hole. The amount of reinforcing bars in the corresponding areas was set, and the reinforcing bars were placed uniformly in the corresponding areas both horizontally and diagonally to the hole. In other words, if the strength of the part that corresponds to the hole in the diagonal direction is satisfied, the strength of the part that corresponds to the horizontal direction is naturally satisfied. However, in some cases, the strength of the part that corresponds to the horizontal direction is satisfied. In some cases, the amount of reinforcing bars is small, and the strength in the horizontal part is insufficient, and the opening occurs in the horizontal part before the shear crack in the 45-degree diagonal direction at the center of the hole. It was found that shear cracks in the upper and lower tangential directions propagate and may cause the beam to fail. For example, under very severe stress conditions where the shear span ratio is relatively small and the aperture ratio diameter (aperture diameter/beam thickness) is large, it is necessary to (see Figure 3), which tend to propagate horizontally across the reinforcing bars in the corresponding area, causing the beam to break. Therefore, it was found that the horizontal parts require the same amount of reinforcement as the diagonal parts.

In other words, the shear stress applied to a perforated beam using the beam shown in Figure 4, in which the horizontal part of the main reinforcement A and the auxiliary reinforcement B are orthogonal to each other, and the one in Figure 5, in which the horizontal part of the main reinforcement and the auxiliary reinforcement B are diagonally crossed. In repeated loading experiments, it was found that the diagonal auxiliary reinforcement B sufficiently inhibited the growth of shear cracks in the tangential direction of the opening, and the cracks were dispersed over a wide range, improving the yield strength and deformability, as shown in Figure 6. , is confirmed by Fig. 7. tree nuts
6 Experimental member angle: Figure 6 shows a crack diagram at I/100. In the figure, solid lines indicate cracks when a positive load is applied, and broken lines indicate cracks when a negative load is applied. Furthermore, an envelope diagram of the load-deformation curve of this experiment is shown in FIG.

The shape of the auxiliary reinforcement is a straight bar, a bent V shape,
Alternatively, it may be of any shape as long as it is connected to the main reinforcement, such as the W-shape shown in the figure.

Also, in order to further improve the strength of the horizontal part of the main reinforcement,
Mesh wire mesh, expanded steel plate, etc. can also be used for the horizontal portion.

The second invention is as follows.

In Figure 8, a horizontal reinforcing bar is tilted at an angle of θ1 at both ends.
o, the left and right inclined parts are the same length, and the extended parts are bent vertically to form main reinforcement 1.
0-1, the inclination angle of the main reinforcement 10-1 with respect to the horizontal part is θ
1O-2 is a horizontal reinforcing bar bent into a V-shape with two sides of the same length, and the angle and length of the left and right slanted parts are determined by bending a horizontal reinforcing bar at a constant angle of inclination at both ends. The auxiliary muscles 20 have the same height.

7 In the upper portion C1o, the inverted V-shaped apex of the main reinforcement 10-2 is fixed at the center of the horizontal portion of the main reinforcement 10-1, and the main reinforcement 1O-1
The inclined part of the main reinforcement 10-2 and the inclined part of the main reinforcement 10-2 are arranged in parallel on the same plane, and the auxiliary reinforcement 2o intersects the main reinforcement 1o-1 and 10-2 on the same plane side, and the horizontal part of the auxiliary reinforcement 20 The horizontal portions of the main reinforcements 10-1 and 10-1 are parallel to each other, and the outer shape of the slanted portion of the auxiliary reinforcement 20 and the main reinforcement 10-1 connected to each other is approximately mouth-shaped (in the figure, the solid line indicates the first layer, and the dotted line indicates the first layer). indicates the second layer).

Next, FIG. 9 shows a reinforcing member consisting of an upper portion CIO and a lower portion C20 having a 180 degree symmetry between the upper portion.

The lower part C20 has an approximately mouth-shaped outer shape, and the reinforcing material is formed by overlapping the inclined parts of the main reinforcements of the upper part C1o and the lower part C2o, and the vertical extensions from the inclined parts of the main reinforcements. The matching intersection points are connected by welding (in the figure, the solid line indicates the first layer, and the dotted line indicates the second layer).
.

In the second invention, as in the first invention, the portion corresponding to the horizontal direction of the hole is reinforced with diagonal reinforcement 8 , which has the effect of improving seismic performance.

When manufacturing the reinforcing material of the present invention, the main reinforcement and auxiliary reinforcement corresponding to the first layer of the reinforcement are placed in the first layer, and then the main reinforcement and auxiliary reinforcement corresponding to the second layer are placed in the second layer. It is conceivable that the two parts are connected together, or that two parts are made for the upper part and the lower part, and the two parts are combined and connected.

[Effects of the Invention] As explained above, the beam through-hole reinforcing material of the present invention can improve seismic performance in terms of strength, and in terms of construction, it consists of two layers in thickness and has a rectangular outer shape. It is easy to install because the corners are rounded.

[Example] Fig. 10 to Fig. 12 show an embodiment of the first invention of the present invention, and Fig. 13 shows an embodiment of the second invention. In the figure, the diagonally shaded layer is the first layer, and the one without the diagonal line is the second layer.

Figure 1θ has a space 3 in the center where the hole of the beam is located, and main reinforcements 1 are arranged diagonally to the main reinforcements and are welded diagonally to the main reinforcements, which are arranged in two parallel rows across the space. A reinforcing material formed from rod-shaped auxiliary reinforcements 2 is shown. In the example shown, the main reinforcement in the upper part and the auxiliary reinforcement in the lower part are 1 in the 1st layer.
．． The auxiliary reinforcement in the E part and the main reinforcement in the lower part are the second layer.

In addition, in the examples shown in FIGS. 11 and 12, the W-shaped auxiliary reinforcement 2 is used, and the outermost main reinforcement 1 further extends the extension line of the left and right inclined parts following the horizontal part of the main reinforcement. The reinforcement is shown extending a certain length in the vertical direction.

Fig. 13 shows a main reinforcement 10 in the center of the horizontal part of the main reinforcement 10-1.
This figure shows a reinforcing material formed by arranging two inverted V-shaped apexes (the bottom points of the V-shape) and auxiliary reinforcements 20 intersecting these main reinforcements.

The intersection points of the main reinforcement and auxiliary reinforcement mentioned above are all connected by welding. Further, these reinforcing materials may be appropriately selected and used depending on the diameter of the hole to be used, the structure and size of the beam, etc.

[Brief explanation of drawings]

1 and 2 are schematic diagrams for explaining the basic configuration of the first aspect of the present invention, and FIG. 3 is an explanatory diagram showing the state of shear cracks occurring at the center of the opening of the reinforcing material. , FIG. 4 is a plan view showing an example of a reinforcing material in which auxiliary reinforcements are orthogonally crossed in the horizontal part of the main reinforcement, FIG.
Figure 6 is an explanatory diagram showing the results of repeated shear force loading experiments on perforated beams, (a) is a diagram when the reinforcement shown in Figure 4 is used, and (b) is a diagram when the reinforcement shown in Figure 5 is used. It is a diagram when used. FIG. 7 is an envelope diagram of the load-deformation curve based on the experiment of FIG. FIG. 8 and FIG. 9 are the second embodiments of the present invention.
Schematic diagram for explaining the basic configuration of the invention, Figure 1O~
FIG. 12 is a plan view showing an embodiment of the first invention, and FIG. 13 is a plan view showing an embodiment of the second invention. A... Main reinforcement, B... Auxiliary reinforcement, C1... Upper part of the reinforcing material of the first invention, C2... Lower part of the reinforcing material of the first invention, C, 0... Second invention The upper part of the reinforcement, C2
o... lower part of the reinforcing material of the second invention, D... white dots,
1... Main reinforcement, 2... Auxiliary reinforcement, 3... Central space,
10-1.10-2...1 Main reinforcement, 20...Auxiliary reinforcement

Claims (1)

[Claims] 1. Bending a horizontal reinforcing bar at a constant angle of inclination at both ends;
In a reinforcing material that consists of main reinforcements with the same angle and length on the left and right inclined parts and auxiliary reinforcements that connect the main reinforcements, the upper part has multiple main reinforcements on the same plane with the horizontal parts parallel to each other at regular intervals. The auxiliary reinforcements in the horizontal part of the main reinforcement are arranged obliquely with the main reinforcement, and the auxiliary reinforcement is arranged symmetrically from the center line of the horizontal part of the main reinforcement, and on the same side as the main reinforcement. The outer shape connected to the main reinforcing bars is approximately ■-shaped, and the lower part is on the same side as the auxiliary reinforcing bars in the upper part, with multiple main reinforcing bars running parallel to each other on the same plane at regular intervals. The auxiliary reinforcements in the horizontal part of the main reinforcement are placed obliquely to the main reinforcement, and the auxiliary reinforcement is symmetrical from the center line of the horizontal part of the main reinforcement.
Furthermore, the outer shape of the main reinforcing bars placed on the same side as the main reinforcing bars in the upper part and connected to the main reinforcing bars is approximately a ■ shape, and the main reinforcing bars in the upper part and the lower part are inclined to each other, or the main reinforcing bars are inclined to each other. A beam of a steel or steel/reinforced concrete structure characterized by having an approximately octagonal outer shape and two layers, in which the vertical extension from the inclined part of the outermost main reinforcement is overlapped and connected. Reinforcement material around the through hole. 2. Bend the horizontal reinforcing bar at a constant angle of inclination at both ends,
Furthermore, the main reinforcement (10-1) whose extension part is bent vertically and the angle and length of the left and right inclined parts are the same, the main reinforcement (10-2) bent into a V shape, and these main reinforcements are In a reinforcing material consisting of auxiliary bars (20) that are connected by bending a horizontal reinforcing bar at both ends with a constant angle of inclination, the left and right inclined parts have the same angle and length, and the upper part is the main bar (10). -1) Main reinforcement (10-2) in the center of the horizontal part
The apex of the inverted V-shape is fixed, and the inclined part of one end of the main reinforcement (10-1), the inclined part of one side of the main reinforcement (10-2), and the inclined part of the other end of the main reinforcement (10-1) are fixed. The slanted part of the main reinforcement (10-2) and the other side of the main reinforcement (10-2) are arranged parallel to each other on the same plane.
-l) and (10-2) on the same side, the horizontal part of the auxiliary reinforcement (20) and the horizontal part of the main reinforcement (10-1) are parallel to each other, and the slope of the auxiliary reinforcement (20) The outer shape of the main reinforcement (10-1) connected to the main reinforcement (10-1) is approximately ■-shaped, and the lower part has the main reinforcement (10-1) on the same side as the auxiliary reinforcement (20) in the upper part.
The bottom point of the V-shape of the main reinforcement (10-2) is fixed at the center of the horizontal part of 1), and the inclined part of one end of the main reinforcement (10-1) and the inclined part of one side of the main reinforcement (10-2) are fixed. Partial and main reinforcement (
10-1) Slanted part at the other end and main reinforcement (10-2)
The inclined parts of the other sides are arranged parallel to each other on the same plane, and the main reinforcements (10-1) and (10-2) of the upper part are arranged parallel to each other on the same plane.
), the auxiliary reinforcement (20) intersects the main reinforcement (10-1) and (10-2), and the horizontal part of the auxiliary reinforcement (20) and the horizontal part of the main reinforcement (10-1) are parallel to each other, and the inclined part of the auxiliary reinforcement (20) and the main reinforcement (10-1)
The connected outer shape is approximately ■-shaped, and the main reinforcement (10-1) and (1
The slanted part of 0-2) and the vertical extension from the slanted part are overlapped and connected, and the external shape is approximately 8.
A reinforcing material around a through-hole in a beam part of a reinforced concrete structure or a steel frame/reinforced concrete structure, which is square in shape and consists of two layers.