JP3247071U - Spacers and rebar cages - Google Patents

Abstract

[Problem] To provide a spacer and a reinforcing cage that can be reliably attached to a reinforcing cage with a simple structure and operation, and that more accurately positions the piles of the reinforcing cage in the radial direction. [Solution] A spacer 1 that is assembled to a reinforcing cage that is composed of main bars arranged vertically and cross bars arranged in a direction perpendicular to the main bars, and has a pair of fastening parts 12 that are fastened to the main bars at two points above and below, a connecting part 11 that is curved or bent so as to be hung across the pair of fastening parts 12, 12, and a pair of hook parts 13, 13 that are formed on each of the fastening parts 12, 12 and hooked onto the cross bars. [Selected drawing] Figure 2

Description

This invention relates to a spacer that is attached to a reinforcing bar cage that is lowered into a pile hole, and to a reinforcing bar cage with the spacer attached.

There are several methods for erecting piles in the ground, including cast-in-place concrete piles, in which a designated area is excavated, a reinforcing bar cage is placed inside, and then concrete is poured into the excavated area, and prefabricated reinforced concrete piles, in which a prefabricated reinforced concrete pile is driven into (or embedded in) the ground.

In the construction of the above-mentioned cast-in-place piles, the casings of steel pipe piles and pile reinforcing cages that are erected in pile holes drilled in the ground require high accuracy in the depth direction and in the radial direction of the pile. As a method for ensuring high accuracy in the depth direction when constructing cast-in-place piles, for example, the method disclosed in Patent Document 1 is known.

The spacer disclosed in Patent Document 1 is used in a construction method in which a large-diameter steel pipe is cast into the ground as a casing, its inside is excavated, a reinforcing bar cage is hung inside the casing, and concrete is poured using a tremie pipe. The spacer is attached to multiple points on the same horizontal plane of the reinforcing bar cage hung inside the casing, at roughly equal positions in plan view. This spacer provides elasticity in the direction of the drilled hole wall, and the pressure arm at the tip of the spacer, which is a pressure member, is long enough to reach the drilled hole wall.

According to the spacer disclosed in Patent Document 1, elastically-imparted pressurized spacers are attached to the reinforcing bar cage at multiple locations on the same horizontal surface, facing the wall of the hole, so that the pressurized spacers apply an even radial pushing force to the center of the reinforcing bar cage. As a result, the reinforcing bar cage is always positioned at the center of the casing, and there is no shortage of reinforcing bar cover thickness due to bias to one side. Furthermore, because elastically-imparted pressurized spacers are attached to the wall of the hole at multiple locations, when the casing is pulled out, the pressurized spacers bite into the wall of the hole. This bite resistance prevents the reinforcing bar from rising, and prevents the reinforcing bar cage from rising together with the casing.

JP 2015-17459 A

However, traditionally, rebars have been assembled and spacers have been attached by welding, but in recent years, due to a shortage of manpower and declining technical capabilities, welding defects have become common. For this reason, it is becoming necessary to assemble rebar cages and attach spacers using methods that do not rely on welding as much as possible. Also, there are situations in which welding itself cannot be used due to the increased strength of rebar steel.

In addition, the spacer disclosed in Patent Document 1 is configured to apply elastic force toward the hole wall by utilizing a spring structure wrapped around the hoop reinforcement. This spring structure increases the complexity of manufacturing and construction, which can lead to higher manufacturing costs and increased construction work, and there are concerns about the difficulty of adapting and adjusting to specific construction environments and conditions.

Furthermore, in the technology disclosed in Patent Document 1, the spring structure exerts elastic force on the hole wall, which can cause the arm to pierce the hole wall, resulting in damage to the hole wall and unnecessary friction, and in some cases, it can even cause damage to the spacer itself and misalignment of the rebar cage. This problem can be particularly pronounced when construction is carried out in areas with hard ground or lots of rocks.

The present invention was made in consideration of the above-mentioned problems with the conventional method, and aims to provide a spacer and a reinforcing cage with the spacer attached that can be securely attached to the reinforcing cage with a simple structure and operation that does not require welding, and that allows for more accurate radial positioning of the piles of the reinforcing cage.

In order to solve the above problems, the spacer of the present invention is:
A spacer to be assembled to a reinforcing bar cage consisting of a main bar arranged vertically and a horizontal bar arranged perpendicular to the main bar,
A pair of fastening parts fastened to the main reinforcement at two points, above and below;
A curved or bent connecting portion that is stretched across the pair of fastening portions;
The fastening portion has a pair of hook portions formed thereon and hooked onto the horizontal bars.

In the above device, the connecting portion, the fastening portion, and the hook portion are integrally formed to form an Ω shape as a whole. In the above device, it is preferable that the pair of hook portions are bent in directions facing each other, and it is preferable that the connecting portion has a rim that protrudes outward along the curved or bent shape. Furthermore, the reinforcing bar cage of the present device is characterized by being equipped with the above-mentioned spacer.

As described above, the present invention allows for more accurate radial positioning of the piles of the reinforcing bar cage while maintaining high workability through a simple configuration. Specifically, the spacer of the present invention is fastened to the main bars in the reinforcing bar cage at two points, above and below, and by hooking a pair of hooks onto the cross bars, it is possible to stably fix the spacer to the main bars and cross bars. As a result, the present invention further strengthens the structural integrity of the reinforcing bar cage, allows for more accurate positioning of the reinforcing bar, improves the structural stability of the reinforcing bar cage, and prevents shifting and distortion of the reinforcing bar when pouring concrete.

In addition, by forming the connecting portion, fastening portion, and hook portion integrally to form an Ω shape, the assembly of the spacer becomes easier, the assembly process of the reinforcing bar cage is simplified, and the construction period can be shortened. Furthermore, by bending the pair of hook portions in mutually opposing directions, the horizontal bars are firmly hooked onto the spacer and prevented from moving, allowing stable fixation to the horizontal bars, and further strengthening the structural integrity of the reinforcing bar cage. Furthermore, if a rim protruding outward is provided on the connecting portion, the strength of the spacer can be increased, and the stability of the spacer can be maintained for a long period of time, while improving its durability and reliability.

FIG. 2 is an explanatory diagram showing an underground pile according to an embodiment. 1A, 1B, and 1C are views showing the appearance of a spacer according to an embodiment of the present invention, in which FIG. 11A, 11B, and 11C are diagrams showing the appearance of a spacer according to a modified example, in which FIG. 1A and 1B are diagrams showing a state in which a spacer according to an embodiment is used, in which FIG. 13A and 13B are explanatory diagrams showing a state in which a spacer according to a modified example is used.

The following describes in detail an embodiment of the spacer according to the present invention and a reinforcing bar cage in which the spacer is used, with reference to the attached drawings. Note that the embodiment shown below is an example of a device for realizing the technical idea of the present invention, and the technical idea of the present invention does not specify the material, shape, structure, arrangement, etc. of each component part as described below. The technical idea of the present invention may be modified in various ways within the scope of the utility model registration claims.

(Outline of underground pile installation method)
An outline of the underground pile installation method according to this embodiment is shown in Fig. 1. In this embodiment, a pile hole G2 is excavated in the ground G1 to construct pile foundations that support buildings when new buildings are built or rebuilt, and piles for civil engineering structures, etc. Next, after the pile hole G2 is excavated in the ground G1, the underground pile is installed by the following steps.

After the pile hole G2 is excavated, a designed rebar cage is inserted into the pile hole G2 and concrete is poured into the pile hole G2. The concrete is usually filled into the pile hole G2 starting from the bottom using a tremie pipe. If necessary, after the concrete is filled into the pile hole G2, a consolidation operation is performed to remove air from the concrete and to cure it for a certain period of time to harden. This curing period is set according to the type of concrete, weather conditions, and the requirements of the structure.

The structure of the reinforcing bar cage 2 will now be described. As shown in FIG. 1, the reinforcing bar cage 2 is a reinforcing bar cage that is installed in an underground pile that is driven into the ground G1. Specifically, the reinforcing bar cage 2 includes a number of main reinforcements 21 arranged parallel to the vertical direction, horizontal reinforcements 22 that connect the main reinforcements 21 horizontally, and a spacer 1 that is fastened and fixed to the main reinforcements 21.

A given number of main reinforcements 21 are arranged at given intervals on the circumference, and each main reinforcement 21 is arranged parallel to the vertical direction, with the multiple main reinforcements 21 forming a cylindrical shape as a whole. Around the outer periphery of the main reinforcements 21, transverse reinforcements 22 are arranged at given intervals in the pile axial direction so as to be perpendicular to the main reinforcements 21. These transverse reinforcements 22 may be ring-shaped hoop reinforcements, or, as in this embodiment, may be spiral reinforcements that are wound around the outer periphery to bundle the multiple main reinforcements 21.

The upper part of the main reinforcement 21 acts as an anchor for the foundation, protruding above the top horizontal reinforcement 22. Steel ring-shaped reinforcement or the like is provided on the inside of the main reinforcement 21 to maintain the circular arrangement of the main reinforcement 21. The reinforcement is attached at appropriate intervals in the axial direction of the pile of the reinforcing bar cage 2.

(Spacer Structure)
As shown in Figure 2, the spacer 1 is fixed along the main bars 21 of the reinforcing bar cage 2, and is roughly composed of a pair of fastening parts 12, 12, a connecting part 11 that is suspended between the pair of fastening parts 12, 12, and a hook part 13 formed on each of the fastening parts 12.

The connecting portion 11 is a curved or bent member that is stretched between a pair of fastening portions 12, 12, and in this embodiment is made of resin or metal and is formed in an arch shape. In this embodiment, the connecting portion 11 has both ends integrally formed with the fastening portions 12. Note that, although the shape of the connecting portion 11 is arch-shaped in this embodiment, it may also be trapezoidal, triangular, arcuate, or a combination of these shapes.

The fastening parts 12, 12 are members fastened to the main reinforcement 21 at two points, one above the other, and the outer ends of each fastening part 12, 12 are bent to form a pair of hooks 13, 13 facing each other, and in this embodiment, the fastening parts 12 and the hooks 13 are integrally formed. In more detail, the fastening parts 12, 12 are bent to be parallel to the main reinforcement 21, and each hook 13 is positioned below (on the main reinforcement side) the formation surface Fs of the fastening part 12, and is bent so that the pair of hooks 13, 13 clamp the cross reinforcement 22 from the outside. In addition, each fastening part 12 has two bolt holes 12a through which bolts can be passed.

In addition, in this embodiment, the connecting portion 11 is formed with a rim 11a that protrudes outward in the direction of curvature along the curved or bent shape, increasing the strength of the curved portion. This rim 11a has a U-shaped cross section and is formed integrally with the connecting portion 11.

In the present embodiment, the spacer 1 described above is formed so that the pair of hooks 13 are positioned below (on the main reinforcement side) the forming surface Fs of the fastening portion 12 and are bent so as to clamp the transverse reinforcement 22 from the outside by the pair of hooks 13, 13. However, as shown in FIG. 3, each hook 13 may be positioned above (on the outside) the forming surface Fs of the fastening portion 12 and each of the pair of hooks 13, 13 may be bent so as to individually grip the transverse reinforcement 22, forming an Ω shape as a whole. In this case, a rim 12b may also be formed on the fastening portion 12.

(how to use)
Next, a method of using the spacer 1 having the above configuration will be described. Figures 4 to 6 show the spacer 1 according to this embodiment in use. As shown in Figures 4(a) and 4(b), the fastening parts 12, 12 are fastened to the main reinforcement 21 at two positions, one above the other. At this time, the pair of hook parts 13, 13 on the outer side of each fastening part 12, 12 clamps the upper and lower cross reinforcements 22, 22 from the upper and lower outside. In this state, the U-shaped bolt 14 is hooked to the main reinforcement 21 and inserted into the bolt hole 12a of the fastening part 12, and the nut 14a is screwed to fix the fastening part 12. As described above, the hook part 13 of the fastening part 12 is disposed on the main reinforcement side relative to the surface on which the fastening part 12 is formed. Therefore, by tightening the nut 14a of the U-shaped bolt 14, the fastening part 12 is pressed against the outer surface of the cross reinforcement 22, and the hook part 13 is more firmly hooked to the cross reinforcement 22.

Similarly, in a configuration in which the hook portion 13 is positioned outward of the formation surface Fs of the fastening portion 12, as shown in FIG. 5(a), by tightening the nut 14a of the U-shaped bolt 14, the fastening portion 12 is pressed directly against the outer surface of the main reinforcement 21, and the hook portion 13 is hooked so as to grip the transverse reinforcement 22, thereby strengthening the hooking of the hook portion 13 to the transverse reinforcement 22.

(Example of change)
The above-described embodiment is an example of the present invention. Therefore, the present invention is not limited to the above-described embodiment, and various modifications can be made according to the design, etc., as long as they do not deviate from the technical concept of the present invention. In the above-described embodiment, the fastening portion 12 is fastened by the U-shaped bolt 14 and the nut 14a, but for example, as shown in FIG. 5(b), the fastening portion 12 and the hook portion 13 may be fastened by a fastening wire 15.

(Action and Effects)
According to the present embodiment described above, the spacer 1 of a simple configuration can maintain high workability while more accurately positioning the reinforcing bar cage 2 in the radial direction of the pile. Specifically, the spacer 1 is fastened to the main reinforcement 21 in the reinforcing bar cage 2 at two points, top and bottom, and can be stably fixed to the main reinforcement 21 and the horizontal reinforcement 22 by hooking the pair of hook parts 13, 13 onto the horizontal reinforcement 22. As a result, according to the present embodiment, the structural integrity of the reinforcing bar cage 2 is further strengthened, the positioning of the reinforcing bar cage 2 can be more accurately performed, the structural stability of the reinforcing bar cage 2 is improved, and it is possible to prevent the reinforcing bar from shifting or warping when pouring concrete.

In addition, the connecting portion 11, fastening portion 12, and hook portion 13 are integrally formed to form an Ω shape, which facilitates the installation of the spacer 1, simplifies the assembly process of the reinforcing cage 2, and shortens the construction period. Furthermore, by bending the pair of hook portions 13, 13 in opposing directions, the cross bars 22 are firmly hooked onto the spacer 1 and prevented from moving, allowing stable fixation to the cross bars 22, further strengthening the structural integrity of the reinforcing cage 2. Furthermore, if a rim 11a protruding outward is provided on the connecting portion 11, the strength of the spacer 1 can be increased, the stability of the spacer 1 can be maintained for a long period of time, and its durability and reliability can be improved.

Fs... Formation surface G1... Ground G2... Pile hole 1... Spacer 2... Reinforcement cage 11... Connection part 11a... Rim 12, 12... Fastening part 13, 13... Hook part 14... U-shaped bolt 14a... Nut 15... Fastening wire 21... Main reinforcement 22, 22... Horizontal reinforcement

Claims (5)

A spacer to be assembled to a reinforcing bar cage consisting of a main bar arranged vertically and a horizontal bar arranged perpendicular to the main bar,
A pair of fastening parts fastened to the main reinforcement at two points, above and below;
A curved or bent connecting portion that is stretched across the pair of fastening portions;
A spacer comprising: a pair of hook portions formed in each of the fastening portions and hooked onto the horizontal bars. The spacer according to claim 1, characterized in that the connecting portion, the fastening portion, and the hook portion are integrally formed to form an Ω shape as a whole. The spacer according to claim 1, characterized in that the pair of hooks are bent in directions opposite to each other. The spacer according to claim 1, characterized in that the connecting portion has a rim that protrudes outward along a curved or bent shape. A reinforcing bar cage comprising a spacer according to any one of claims 1 to 4.