JP7797111B2 - Hydraulic solidified embedded reinforcement steel bar joint structure - Google Patents

Description

The present invention relates to a steel bar joint structure for reinforcing steel bars embedded in hydraulically solidified materials.

Conventionally, when constructing a structure made of hydraulically solidified bodies, it has been necessary to use long reinforcing steel bars embedded in the hydraulically solidified bodies, but the length of the reinforcing steel bars is limited due to transportation constraints, etc., so they have been joined on-site to achieve longer lengths. Joints are used to join reinforcing steel bars embedded in hydraulically solidified bodies, and the reinforcing steel bars are connected by inserting them into openings on both ends of the joint (see, for example, Patent Document 1).
An example of a reinforcing steel rod for embedding in a hydraulically solidified body is disclosed in Patent Document 2, which shows a reinforcing steel rod for embedding in a hydraulically solidified body having a substantially circular cross section, on part of the outer surface of which a number of parallel longitudinal ridges are arranged at substantially equal intervals along the entire axial length of the reinforcing steel rod for embedding in a hydraulically solidified body.

Japanese Patent Application Laid-Open No. 2018-178365 Patent No. 1227542 Japanese Unexamined Patent Publication No. 56-135658

The joint described in Patent Document 1, mentioned above, requires the hardenable filler to be filled inside the steel rod receiving section, where the steel rod is loosely fitted, resulting in tasks such as transporting and mixing the hardenable filler at the construction site, which increases the workload. Furthermore, while the steel rod is loosely fitted in the steel rod receiving section, the hardenable filler is filled through an injection hole located in the longitudinal center of the joint. However, during filling, the hardenable filler leaks from the openings at both ends of the joint's length, preventing the joint from being fully filled. Therefore, nuts must be tightened on both ends of the joint to close the openings. These issues pose a number of challenges, including an increase in the number of required parts and the amount of work required, as well as the time required to align the axes of the two steel rods inserted into the joint.

Furthermore, reinforcing steel rods for embedding hydraulic solidified bodies, such as those described in Patent Document 2 and Patent Document 3, are said to have problems with the adhesion of the hydraulic solidified bodies when they are embedded.

The present invention was developed through extensive research by the inventors in light of the above-mentioned problems, and aims to provide a means for easily positioning and fixing a joint structure for a reinforcing steel rod embedded in a hydraulically solidified body at the desired axial position of the reinforcing steel rod using a simple structure, improving the connectivity between reinforcing steel rods embedded in a hydraulically solidified body, and improving the pull-out strength when embedded in the hydraulically solidified body.

A joint structure for a steel rod for reinforcing a hydraulically solidified body embedded in a hydraulically solidified body according to one aspect of the present invention is a joint structure for a steel rod for reinforcing a hydraulically solidified body embedded in a hydraulically solidified body, which has an insertion hole through which a steel rod for reinforcing a hydraulically solidified body embedded in a hydraulically solidified body can be inserted in the axial direction, and the inner periphery is engaged with a rib of the steel rod for reinforcing a hydraulically solidified body to connect the steel rod for reinforcing a hydraulically solidified body embedded in a hydraulically solidified body, and the inner periphery is provided with engaging protrusions arranged in a row in the axial direction and capable of engaging with the ribs, and small recesses arranged alternately with the engaging protrusions in the axial direction and capable of fitting the ribs. and a large diameter surface circumferentially adjacent to the engaging protrusion and the concave portion and not engaging with the rib, wherein the non-helical shapes of the concave portions are symmetrical and asymmetrical with the axial direction as an axis of symmetry when viewed in the radial direction, and are arranged in a row in the axial direction, forming a hybrid structure in which the symmetrical shapes and the asymmetrical shapes are arranged, and the rib is fitted into the concave portion to restrict axial displacement of the hydraulically solidified body-buried reinforcing steel rod.
Another aspect of the present invention is a joint structure for a steel rod for embedded reinforcement of a hydraulically solidified body, which has an insertion hole through which a steel rod for embedded reinforcement of a hydraulically solidified body can be inserted in the axial direction, and whose inner periphery engages with the ribs of the steel rod for embedded reinforcement to connect the steel rod, characterized in that the inner periphery has engaging protrusions arranged in a row in the axial direction and capable of engaging with the ribs, at least one type of concave portion alternately arranged with the engaging protrusions in the axial direction and recessed so that the ribs can be fitted therein, and large-diameter surfaces circumferentially adjacent to the engaging protrusions and the concave portions and not engaged with the ribs, and the insertion hole has a hole shape that is approximately oval or approximately elliptical when viewed in the axial direction, and the ribs are fitted into the concave portions to restrict axial displacement of the steel rod for embedded reinforcement of a hydraulically solidified body.

Furthermore, the hydraulically solidified body-embedded reinforcing steel rod joint structure of the present invention is characterized in that the symmetrical shape has closed ends at both circumferential ends, the main body of the hydraulically solidified body-embedded reinforcing steel rod joint structure has an expansion section that allows the internal space to be expanded, and the expansion section is capable of transitioning between a state in which the rib is received on the inner periphery and a state in which the insertion hole is expanded to receive the rib on the inner periphery.

Furthermore, the hydraulically solidified body buried type reinforcing steel rod joint structure of the present invention is characterized in that the expansion section has an elastic deformation mechanism and/or a radial separation mechanism.

Furthermore, the hydraulically solidified body-embedded reinforcing steel bar joint structure of the present invention is characterized in that one circumferential end of the asymmetrically shaped concave portion is open, and the rib can be received from the open end side.

Furthermore, the hydraulically solidified body-embedded reinforcing steel bar joint structure of the present invention is characterized in that the other circumferential end of the asymmetrically shaped concave portion is a closed end, and this closed end can restrict circumferential displacement of the rib.

Furthermore, the hydraulically solidified body buried type reinforcing steel rod joint structure of the present invention is characterized in that the concave portion is spiral-shaped, and the radial end of the engaging convex portion is planar, convexly curved, or acute-angled.

Furthermore, the hydraulically solidified body embedded type reinforcing steel bar joint structure of the present invention is characterized in that the spiral-shaped recessed portion is formed continuously or intermittently along a virtually set spiral path.

Furthermore, the hydraulically solidified body-buried reinforcing steel bar joint structure of the present invention is characterized in that the spiral-shaped recessed portion is formed continuously, and the width of the recessed portion narrows gradually or in stages from one end to the middle in the axial direction.

Furthermore, the joint structure of the hydraulically solidified body-embedded reinforcing steel rod of the present invention is characterized in that the insertion hole has a hole shape, when viewed in the axial direction, that is generally similar or approximate to the outer shape of the hydraulically solidified body-embedded reinforcing steel rod as viewed in the axial direction.

The hydraulically solidified body buried reinforcing steel rod joint structure of the present invention is also characterized in that the insertion hole has a two-sided width portion, and the opposing ends of the opposing two-sided width portion are connected by an inner circumferential surface that forms a convex arc with a predetermined radius of curvature.

Furthermore, the hydraulically solidified body-buried reinforcing steel bar joint structure of the present invention is characterized in that the insertion hole has different cross-sectional areas in a first range extending from one end to the middle of the axial direction and a second range extending from the other end to the middle of the axial direction.

Furthermore, the hydraulically solidified body-buried reinforcing steel bar joint structure of the present invention is characterized in that the concave portion from one end to the middle of the axial direction is spirally shaped, and the concave portion from the other end to the middle of the axial direction is non-spirally shaped.

Furthermore, the hydraulically solidified body embedded type reinforcing steel rod joint structure of the present invention is characterized by the provision of a relative rotation prevention member at at least one axial end to prevent relative rotation with the hydraulically solidified body embedded type reinforcing steel rod.

Furthermore, the hydraulically solidified body embedded reinforcing steel rod joint structure of the present invention is characterized by the provision of a relative displacement prevention member at at least one axial end to prevent relative axial displacement with respect to the hydraulically solidified body embedded reinforcing steel rod.

Furthermore, the joint structure of the hydraulically solidified body-embedded reinforcing steel rod of the present invention is characterized by having a rigid connection structure at the axial end, and the rigid connection structure having a relative rotation prevention member that prevents relative rotation with the hydraulically solidified body-embedded reinforcing steel rod, and a relative displacement prevention member that prevents relative displacement with respect to the hydraulically solidified body-embedded reinforcing steel rod.

Furthermore, the hydraulically solidified body embedded reinforcing steel rod joint structure of the present invention is characterized in that the relative rotation prevention member surrounds the hydraulically solidified body embedded reinforcing steel rod and is inserted into the engagement hole.

Furthermore, the hydraulically solidified body embedded type reinforcement steel rod joint structure of the present invention is characterized in that the relative rotation prevention member has an engagement surface that engages with the inner periphery of the engagement hole, and a non-circular hydraulically solidified body embedded type reinforcement steel rod insertion hole that roughly corresponds to the outer shape of the hydraulically solidified body embedded type reinforcement steel rod when viewed in the axial direction, and the hydraulically solidified body embedded type reinforcement steel rod can be fitted into the hydraulically solidified body embedded type reinforcement steel rod insertion hole in a state where relative rotation is prevented, and the engagement surface engages with the inner periphery of the engagement hole.

Furthermore, the hydraulically solidified body embedded reinforcing steel rod joint structure of the present invention is characterized in that the relative displacement prevention member engages with the rib of the hydraulically solidified body embedded reinforcing steel rod, thereby restricting axial displacement.

Furthermore, the hydraulically solidified body embedded reinforcing steel rod joint structure of the present invention is characterized in that the relative displacement prevention member has a hole portion with a spiral groove on the inner peripheral surface through which the hydraulically solidified body embedded reinforcing steel rod can be inserted.

Furthermore, the hydraulically solidified body buried type reinforcing steel bar joint structure of the present invention is characterized in that a relative rotation prevention mechanism that prevents relative rotation between the relative rotation prevention member and the relative displacement prevention member is provided at the contact portion between the relative rotation prevention member and the relative displacement prevention member.

The hydraulically solidified body buried reinforcing steel rod joint structure of the present invention is also characterized by having a through hole at an appropriate intermediate position in the longitudinal direction of the main body, which allows the insertion depth of the hydraulically solidified body buried reinforcing steel rod to be visually confirmed.

Furthermore, the hydraulically solidified body buried reinforcing steel rod joint structure of the present invention is characterized in that the confirmation hole has a center position indication means that indicates the center of the longitudinal direction.

Furthermore, the hydraulically solidified body buried type reinforcing steel rod joint structure of the present invention is characterized in that the confirmation hole has a constricted portion formed by constricting the hole shape at a point corresponding to the center in the longitudinal direction, and this constricted portion constitutes the center position indication means.

Furthermore, the hydraulically solidified body buried reinforcing steel rod joint structure of the present invention is characterized in that the confirmation hole is blocked with a light-transmitting member.

This invention uses a simple structure to easily position and fix a joint structure for a reinforcing steel rod embedded in a hydraulically solidified body at the desired axial position of the reinforcing steel rod, improving the connectivity between the reinforcing steel rods embedded in a hydraulically solidified body and increasing the pull-out strength when embedded in the hydraulically solidified body.

1A and 1B show a hydraulically solidified body-buried reinforcing steel rod according to this embodiment, in which FIG. 1A is a front view and FIG. 1B is a cross-sectional view taken along line AA. 1 is a view showing a rib of a hydraulically solidified body buried type reinforcing steel bar according to an embodiment of the present invention. FIG. FIG. 2 is a cross-sectional view showing a hydraulically solidified body buried reinforcing steel rod. 10A to 10C show other examples of the shape of the rib, where (a) is a side view, (b) is a front view, and (c) is a cross-sectional view. 1A and 1B show a hydraulically solidified body-buried reinforcing steel bar joint structure according to an embodiment of the present invention, in which FIG. 1A is a plan view and FIG. 1B is a cross-sectional view. FIG. 1 is a cross-sectional view showing a hydraulically solidified body buried reinforcing steel bar joint structure. 5A and 5B are diagrams showing the rib entering the recessed portion, in which FIG. 5A is a diagram showing the position before entering the recessed portion, and FIG. 5B is a diagram showing the position when fitted into the recessed portion. 10A and 10B are diagrams illustrating examples of the shape of a tip portion. 10A and 10B are diagrams showing other examples of inner circumference shapes of a hydraulically solidified body buried reinforcing steel bar joint structure. 5A and 5B are diagrams showing the rib entering the recessed portion, in which FIG. 5A is a diagram showing the position before entering, and FIG. 5B is a diagram showing the position when fitted into the recessed portion. FIG. 10A to 10C show another example of a hydraulically solidified body buried type reinforcing steel bar joint structure, where (a) is a plan view, (b) is a front view, and (c) is a cross-sectional view taken along the line A-A in (b). 10 is a diagram showing a slit whose width has been increased by elastic deformation of a thin-walled portion. FIG. FIG. 10 is a perspective view showing another example of a hydraulically solidified body buried reinforcing steel bar joint structure. FIG. 10 is a diagram showing the range over which a slit can expand. 1A and 1B show a partial body forming a part of a hydraulically solidified body buried type reinforcing steel bar joint structure, in which FIG. 1A is a perspective view and FIG. 1B shows the outer peripheral surface on the connecting portion side. FIG. 1 is a perspective view showing a hydraulically solidified body buried reinforcing steel bar joint structure composed of partial bodies. FIG. 10 is a perspective view showing another example of a hydraulically solidified body buried reinforcing steel bar joint structure. FIG. 10 is a diagram showing the connection of two steel rods for reinforcing a hydraulically solidified body buried type using a joint structure for the steel rod for reinforcing a hydraulically solidified body buried type. 1 shows a steel rod joint structure for reinforcing steel rods embedded in hydraulically solidified bodies, which has a non-helical concave portion and a helical concave portion, where (a) is an oblique view, (b) is a front view, and (c) is an A-A cross-sectional view of (b). 1A, 1B, and 1C show a relative rotation prevention member that engages with a hydraulically solidified body-buried reinforcing steel rod joint structure, in which FIG. 1A is a perspective view, FIG. 1B is a side view, and FIG. 1C is a cross-sectional view. 1A is a perspective view of a relative displacement prevention member, FIG. 1B is a side view thereof, and FIG. 1C is a cross-sectional view thereof. FIG. 1 is a diagram showing a connection between a hydraulically solidified body buried type reinforcing steel rod joint structure and a hydraulically solidified body buried type reinforcing steel rod. 10A and 10B are diagrams illustrating the installation of a relative rotation prevention member and a relative displacement prevention member. 10A and 10B are diagrams illustrating another example of a relative rotation prevention member. FIG. FIG. 10 is a diagram showing a steel rod joint structure for reinforcing a hydraulically solidified body buried type, which is formed by connecting cylindrical members. 10A to 10C show examples of other shapes of the rib, where FIG. 10A is a perspective view, FIG. 10B is a plan view, and FIG. 10C is a side view.

An embodiment of a hydraulically solidified body-embedded reinforcing steel rod joint structure for connecting hydraulically solidified body-embedded reinforcing steel rods of the present invention will be described below with reference to the drawings. The hydraulically solidified body-embedded reinforcing steel rod joint structure is composed of a member that forms a tubular member as a whole, and is connected to hydraulically solidified body-embedded reinforcing steel rods inserted into its ends. By inserting hydraulically solidified body-embedded reinforcing steel rods into both ends, the hydraulically solidified body-embedded reinforcing steel rods are connected to each other. Therefore, the hydraulically solidified body-embedded reinforcing steel rod joint structure has a structure for engaging with hydraulically solidified body-embedded reinforcing steel rods.

FIG. 1 shows a hydraulically solidified body-embedded reinforcing steel rod 1 according to this embodiment, where (a) is a front view and (b) is an A-A cross-sectional view. FIG. 2 is a side view showing a rib 4 of the hydraulically solidified body-embedded reinforcing steel rod 1 according to this embodiment. The hydraulically solidified body-embedded reinforcing steel rod 1 is a long steel member that is embedded in the hydraulically solidified body to reinforce it. The hydraulically solidified body-embedded reinforcing steel rod 1 has reduced diameter surfaces 2 located in two predetermined regions facing each other across its axis, ribs 4 arranged in a row in the axial direction and protruding radially outward, and concave diameter surfaces 6 that are alternately recessed in the ribs 4 along the axial direction. The hydraulically solidified body-embedded reinforcing steel rod 1 can be made of any suitable material, such as steel.
The reduced diameter surface 2 extends in the axial direction and is formed so that the radius from the axis gradually decreases toward the circumferential center of the region. The reduced diameter surface 2 may have, for example, a two-face width formed on the hydraulically solidified body-buried reinforcing steel bar 1.

The concave surface 6 is set so that its distance from the axis is within the range of the distance from the axis of the reduced diameter surface 2. For example, the concave surface 6 can be set so that its distance from the axis is equivalent to the radius of the circumferential center or both ends of the reduced diameter surface 2.

As shown in Figure 2, the rib 4 has a tip 10 at its radial end. The ridge 12 forming the tip 10 extends perpendicular to the axis, with both circumferential ends extending toward the reduced diameter surface 2. The rib 4 also has four surfaces 14a-14d facing in different normal directions. These four surfaces 14a-14d are each arranged along an imaginary spiral surface assumed around the axis of the hydraulically solidified body-buried reinforcing steel bar 1.

The four faces 14a to 14d form a roughly quadrangular pyramid shape when the outer surface of the hydraulically solidified body buried reinforcing steel bar 1 is unfolded (unfolded) on an imaginary plane. Of the four faces 14a to 14d, the upper left in the orientation shown in Figure 2 is face 14a, the lower left is face 14b, the upper right is face 14c, and the lower right is face 14d.

The ridges 12 that form the boundaries between surfaces 14a and 14b, and between surfaces 14c and 14d, extend perpendicular to the axis, with both ends facing the reduced diameter surface 2. Furthermore, surfaces 14a to 14d have a shape that narrows in the axial direction of the hydraulically solidified body-embedded reinforcing steel bar 1 toward the circumferential end located on the reduced diameter surface 2 side, i.e., a shape that narrows in width. Therefore, the circumferential end of the rib 4 forms a sharp tip 10.

The cross-sectional shape of the tip 10 may be approximately acute or obtuse, or may be approximately arc-shaped, or may have a slightly flat surface. However, a slightly arc-shaped cross-section is preferable, as it is easier to manufacture and less susceptible to damage, and as described below, it also improves fit with the hydraulically solidified body buried reinforcing steel rod joint structure.

The ribs 4 and recessed surfaces 6 are provided in two opposing regions across the axis, and the axial positions of the ribs 4 and recessed surfaces 6 in each region are set to be staggered. That is, the ribs 4 in one region are positioned at the same position as the recessed surfaces 6 in the other region across the axis. Similarly, the ribs 4 in one region are positioned at the same position as the recessed surfaces 6 in the other region. Of course, the axial positions of the ribs 4 and recessed surfaces 6 may also be set to coincide.

The rib 4 protrudes radially outward most at its center, and its radial protrusion length gradually decreases toward its circumferential ends. In other words, the ridge line 12 of the rib 4 is located inside an imaginary circle C whose radius extends from the axis of the hydraulically solidified body-embedded reinforcing steel bar 1 shown in Figure 1(b) to the point where the rib 4 protrudes the longest. The rib 4 has an end surface 4a that connects to the reduced diameter surface 2 at its circumferential ends and is substantially flush with the reduced diameter surface 2.

The connection of the rib 4 to the reduced diameter surface 2 may be made, for example, by setting a ridge line 12 in the shape of a curve 13a at the circumferential end of the rib 4 as shown in Figure 3(a), or by setting a ridge line 12 in the shape of a straight line 13b at the circumferential end of the rib 4 as shown in Figure 3(b).

4 shows another shape of the rib 4, where (a) is a side view, (b) is a front view, and (c) is a cross-sectional view taken along line B-B of (a), and the rib 4 may be set so that the radial protrusion length at the circumferential end is approximately zero as shown in Fig. 4. In this case, the protrusion length of the rib 4 is set so that it gradually decreases at an approximately constant rate.
Of course, the protruding length of the rib 4 is not limited to a shape that gradually reduces along the circumferential direction, but may be a substantially constant shape in a predetermined region from the center to the circumferential end, but the ridge line 12 at the circumferential end is set to the curve 13a or straight line 13b as described above and connected to the reduced diameter surface 2.

Furthermore, the tip of the rib 4 may have an approximately triangular pyramid shape with a three-dimensional curved surface at both circumferential ends, each of which is set smaller than the curved, slender triangular pyramid spatial region surrounded by imaginary extension planes formed by extending the four faces 14a to 14d in the direction of rotation about the axis. In other words, both circumferential ends of the rib 4 may have a three-dimensional curved surface whose protruding length in the direction perpendicular to the axis gradually decreases so that they are located radially inward from faces 14a to 14d. Furthermore, this three-dimensional curved surface may have an approximately triangular pyramid shape, but it can also have a curved surface shape. Furthermore, the rib 4 may have a shape such that both ends are not connected to the reduced diameter surface 2, i.e., have a length that allows them to be separated from the reduced diameter surface 2 in the circumferential direction.

Figure 28 shows other examples of the shape of the rib 4, with (a) being a perspective view, (b) being a plan view, and (c) being a side view. Ribs 4 having a three-dimensional curved surface whose protruding height in the direction perpendicular to the axis gradually decreases may have a boundary portion 151 between the rib engagement portion 150 in the central portion and the tip portion 152 in the circumferential direction shown in Figure 28. Furthermore, the rib 4 is configured so that its radial protruding height is greatest at the central portion and gradually decreases toward the tip portion 152, approaching approximately zero at the point closest to the reduced diameter surface 2.

Specifically, the rib 4 has a generally mountain-shaped slope along the circumferential direction so that the protruding height gradually decreases from the center of the rib engagement portion 150 toward the tip 152, with the slope from the boundary portion 151 toward the tip 152 being steeper than the slope of the rib engagement portion 150. Furthermore, the rib engagement portion 150 axially engages with the recessed portion 26, which will be described later, and the reduction in the protruding height is set to be more gradual than that of the tip 152 in order to maintain the shear strength of the rib 4.

As mentioned above, reinforcing steel rods for embedding hydraulic solidified bodies, such as those described in Patent Document 2 and Patent Document 3, have the problem of poor adhesion of the hydraulic solidified bodies when they are embedded. However, with the reinforcing steel rod 1 for embedding hydraulic solidified bodies of the present invention, by using a shape with four surfaces 14a-14d like the rib 4 described above, or a shape with a rib engaging portion 150 and a tip portion 152 as shown in Figure 28, adhesion of the hydraulic solidified bodies can be improved, and the rib 4 can be easily screwed into the reinforcing steel rod joint structure 20 for embedding hydraulic solidified bodies, which will be described later.

Furthermore, the protruding height of the rib 4 may be set large to improve the pull-out strength when the hydraulically solidified body is buried. However, if the protruding height of the rib 4 is large, the rib 4 may extend up to the reduced diameter surface 2, or may protrude radially outward beyond the reduced diameter surface 2 at a position adjacent to the reduced diameter surface 2. Therefore, processing such as cutting the rib 4 is required to form the reduced diameter surface 2. In contrast, with the rib 4 shaped as shown in Fig. 28, the gradient of the inclination is made different between the rib engaging portion 150 between the boundary portion 151 and the tip portion 152, thereby improving mass productivity while maintaining the pull-out strength.
Therefore, if the steel rod 1 for reinforcing a hydraulically solidified body to be buried has a rib 4 with a rib locking portion 150 and a tip portion 152, it is possible to continue to form the intended shape with high precision when mass-producing the steel rods 1 for reinforcing a hydraulically solidified body to be buried. Furthermore, since the rib 4 has the tip portion 10 (152), it can be easily fitted into the recessed portion 26 of the joint structure 20 for reinforcing a hydraulically solidified body to be described later, thereby improving connectivity.

Next, we will explain the hydraulically solidified body embedded reinforcing steel rod joint structure 20. The hydraulically solidified body embedded reinforcing steel rod joint structure 20 is a joint that connects two hydraulically solidified body embedded reinforcing steel rods 1, and has an inner peripheral shape that can surround the hydraulically solidified body embedded reinforcing steel rods 1, with insertion holes that run through in the axial direction and open at both ends.

Figure 5 shows a hydraulically solidified body-embedded reinforcing steel rod joint structure 20 according to this embodiment, with (a) being a plan view and (b) being a cross-sectional view. The hydraulically solidified body-embedded reinforcing steel rod joint structure 20 has an inner peripheral surface surrounding the hydraulically solidified body-embedded reinforcing steel rod 1. The inner peripheral surface is provided with large-diameter surfaces 22 positioned opposite each other across the axis, and engaging protrusions 24 and recesses 26 circumferentially adjacent to the large-diameter surfaces 22.

The large diameter surface 22 is set so that it is approximately equidistant from the axis and is located radially outward of the ribs 4 when surrounding the hydraulically solidified body-buried reinforcing steel bar 1. In other words, it has a larger radius than the ribs 4 so that it is generally not in contact with the ribs 4. Note that the large diameter surface 22 is not limited to being approximately equidistant from the axis, and may be set so that its distance from the axis center varies along the circumferential direction, as long as it is at least not in contact with the ribs 4.

The engaging protrusions 24 protrude radially inward from the large diameter surface 22, extend circumferentially, and are arranged in multiple rows in the axial direction. Furthermore, the distance from the axial center of the engaging protrusions 24 is set so that, when they surround the hydraulically solidified body-buried reinforcing steel bar 1, they are positioned radially outward from the reduced diameter surface 2.

The recessed portions 26 are depressions that have a concave shape relative to the engaging protrusions 24, and are arranged alternately with the engaging protrusions 24 in the axial direction. The depth of the recessed portions 26 is set so that, at a predetermined relative position, their bottoms are positioned at least radially outward of the ribs 4. That is, the depth of the recessed portions 26 may be set so that they are approximately equidistant from the axis, and they may be connected to the large diameter surface 2 so as to form an approximately continuous surface. Of course, the depth of the recessed portions 26 may also be set so that they are further from the axis than the large diameter surface 22.

In addition, when viewed in the radial direction, the recessed portion 26 has an asymmetric shape with respect to an axis of symmetry parallel to the axial direction. That is, one circumferential end (the left end in FIG. 5(b)) forms an open end 28 with a widened width, and the width gradually decreases toward the other end (the right end in FIG. 5(b)), which forms a closed end that restricts circumferential displacement of the rib 4. Here, the closed end is formed by disposing a wall-shaped stopper 29 that protrudes radially from the bottom surface of the recessed portion 26 on the other end side. Furthermore, the radial protruding length of the stopper 29 is set so as to restrict at least circumferential displacement of the rib 4.

The engaging protrusions 24 and recessed portions 26 are arranged in two opposing regions across the axis to correspond to the ribs 4 and recessed surfaces 6 of the reinforcing steel bar 1 for embedding in a hydraulically solidified body, with the engaging protrusions 24 in one region and the engaging protrusions 24 in the other region being set so that their axial positions are offset from each other. Of course, the engaging protrusions 24 and recessed portions 26 may be set opposite the engaging protrusions 24 and opposite the recessed portions 26 so that their axial positions are not offset from each other, corresponding to the configuration of a reinforcing steel bar 1 for embedding in a hydraulically solidified body in which the ribs 4 are set at the same axial positions.

Here, Figure 6 is a cross-sectional view showing a hydraulically solidified body buried reinforcing steel bar joint structure 20, illustrating the positional relationship between the engaging protrusions 24 and recesses 26 in two opposing regions spaced apart in the radial direction. As shown in Figure 6, for one region located on the left, an engaging protrusion 24 is provided, while for the other region located on the right, a recess 26 is provided; and for one region, an engaging protrusion 24 is provided, while for the recess 26, another region is provided.

Therefore, by making the engaging protrusions 24 and recessed portions 26 staggered, just like the ribs 4 and recessed surfaces 6 of the hydraulically solidified body-embedded reinforcing steel rod 1, the ribs 4 of the hydraulically solidified body-embedded reinforcing steel rod 1 can fit into each recessed portion 26. Note that if the hydraulically solidified body-embedded reinforcing steel rod 1 has a shape in which the axial positions of the ribs 4 and recessed surfaces 6 are aligned in two opposing regions across the axis, the axial positions of the engaging protrusions 24 and recessed portions 26 are aligned.

Next, the procedure for connecting a hydraulically solidified body-embedded reinforcing steel rod 1 to a hydraulically solidified body-embedded reinforcing steel rod joint structure 20 will be described. First, the hydraulically solidified body-embedded reinforcing steel rod 1 is inserted into the insertion hole of the hydraulically solidified body-embedded reinforcing steel rod joint structure 20. At this time, the reduced diameter surface 2 of the hydraulically solidified body-embedded reinforcing steel rod 1 is aligned with the engaging protrusion 24 and recess 26 of the hydraulically solidified body-embedded reinforcing steel rod joint structure 20. At this time, the hydraulically solidified body-embedded reinforcing steel rod 1 can be inserted axially without coming into contact with the hydraulically solidified body-embedded reinforcing steel rod joint structure 20. That is, because the reduced diameter surface 2 is located radially inward of the engaging protrusion 24 and the rib 4 is located radially inward of the large diameter surface 22, the hydraulically solidified material embedded reinforcing steel rod 1 can be inserted without contacting the hydraulically solidified material embedded reinforcing steel rod joint structure 20, and can be displaced axially.

After inserting the hydraulically solidified body-embedded reinforcing steel rod 1, the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 is rotated circumferentially relative to the hydraulically solidified body-embedded reinforcing steel rod 1, and the hydraulically solidified body-embedded reinforcing steel rod 1 is fixed to the hydraulically solidified body-embedded reinforcing steel rod joint structure 20. Figure 7 shows a schematic diagram of the rib 4 entering the recessed portion 26, with (a) showing the position before entering the recessed portion 26 and (b) showing the position when fitted into the recessed portion 26. Note that Figure 7 shows the inner circumferential surface of the hydraulically solidified body embedded reinforcing steel rod joint structure 20 on the front side, and since surfaces 14a to 14d of rib 4 face the recessed portion 26, the hydraulically solidified body embedded reinforcing steel rod 1 (not shown) is positioned on the front side of the page, with the ridge line 12 of rib 4 shown with dotted lines, and surfaces 14a to 14d facing the recessed portion 26 toward the back of the page.

The hydraulically solidified body-embedded reinforcing steel rod joint structure 20 rotates in a predetermined direction so that the rib 4 shown in Figure 7(a) enters the recessed portion 26 from the open end 28. The hydraulically solidified body-embedded reinforcing steel rod joint structure 20 is also rotated in a relative direction so that the rib 4 shown in Figure 7(b) fits into the recessed portion 26 and the leading end of the rib 4 in the direction of travel abuts the closed end of the recessed portion 26.

When the rib 4 enters between the engaging protrusions 24, the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 is restricted from axial displacement relative to the hydraulically solidified body-embedded reinforcing steel rod 1. In other words, relative displacement between the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 and the hydraulically solidified body-embedded reinforcing steel rod 1 is restricted in both the pull-out and push-in directions of the hydraulically solidified body-embedded reinforcing steel rod 1 relative to the hydraulically solidified body-embedded reinforcing steel rod joint structure 20. Furthermore, when the rib 4 abuts the closed end of the hydraulically solidified body-embedded reinforcing steel rod joint structure 20, circumferential displacement along a predetermined rotational direction relative to the hydraulically solidified body-embedded reinforcing steel rod 1 is restricted. Therefore, the hydraulically solidified body buried reinforcing steel rod 1 is connected and fixed to the hydraulically solidified body buried reinforcing steel rod joint structure 20.

The rib 4 of the hydraulically solidified body-embedded reinforcing steel rod 1 has a pointed tip 10, and the open end 28 of the recessed portion 26 of the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 has a widened shape. This prevents the engaging protrusion 24 from getting caught on the rib 4 when the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 is rotated, making it easier to fit the rib 4 into the recessed portion 26.

4, the rib 4 can be more easily fitted into the recessed portion 26 without getting caught, which is preferable. As long as the engaging protrusion 24 has a surface at the circumferential end, even if the tip 10 is sharpened, the rib 4 and the engaging protrusion 24 will come into contact, and the relative rotation of the hydraulically solidified body-embedded steel rod joint structure 20 with respect to the hydraulically solidified body-embedded steel rod 1 for reinforcing may be restricted.
Therefore, as shown in Figure 8(a), it is preferable to further widen the open end 28, i.e., to form a guide shape that is greatly expanded in the axial direction, and to sharpen the circumferential end of the engaging protrusion 24. Furthermore, it is even more preferable to form the tip portion 10 and the circumferential end of the engaging protrusion 24 into a sharp shape, as shown in Figure 8(b). This prevents the ends from coming into contact with each other, and the rib 4 is more automatically guided into the recessed portion 26, making it easier to fit together, facilitating the connection between the steel bar 1 for hydraulically solidified body-embedded reinforcement and the joint structure 20 for a steel bar for hydraulically solidified body-embedded reinforcement.

The hydraulically solidified body-embedded reinforcing steel rod joint structure 20 is connected to the hydraulically solidified body-embedded reinforcing steel rod 1 by rotating it relative to the hydraulically solidified body-embedded reinforcing steel rod 1, but since the open end 28 is formed in the recessed portion 26, the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 is in a state where it can rotate in the reverse direction. If the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 rotates in the reverse direction, the connection between the hydraulically solidified body-embedded reinforcing steel rod 1 and the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 will be released.
Therefore, a reverse rotation prevention structure may be provided between the hydraulically solidified body-embedded reinforcing steel rod 1 and the hydraulically solidified body-embedded reinforcing steel rod joint structure 20. For example, the reverse rotation prevention structure can be formed by changing the shape of the recessed portion relative to the rib 4. Here, Fig. 9 is a view seen from the radial direction showing another example of the inner peripheral shape of the hydraulically solidified body-embedded reinforcing steel rod joint structure 20. For example, the axial length (width) of the recessed portion 30 can be reduced on the open end 32 side, i.e., the open end 32 of the recessed portion 30 can be made narrower than the middle portion to form the reverse rotation prevention structure.

In this case, the width of the open end 32 is set smaller than the maximum width of the rib 4 (the width at the circumferential center). The difference between the width of the open end 32 and the maximum width of the rib 4 is set to a degree that allows the rib 4 and/or the engaging protrusion 24 to elastically deform and enter the recessed portion 30.

Figure 10 is a schematic diagram showing the entry of rib 4 into recessed portion 30, with (a) showing the position before entry into recessed portion 30 and (b) showing the position when engaged with recessed portion 30. In Figure 10, the approximate positions of surfaces 14a and 14b located on the far side of the page are indicated by dotted lines and corresponding symbols. As shown in Figure 10(a), surfaces 14a and 14b of rib 4 abut against engaging protrusion 24 on the open end 32 side of recessed portion 30, but by pushing against this resistance, surfaces 14a, 14b and/or engaging protrusion 24 are elastically deformed, allowing rib 4 to enter recessed portion 30 as shown in Figure 10(b).

By fitting the rib 4 into the recessed portion 30 in this way, even if a torque or the like is applied in the opposite direction to the rotational direction when the hydraulically solidified body embedded steel rod joint structure 20 is connected to the hydraulically solidified body embedded steel rod 1 for reinforcement, in order for the rib 4 to be disengaged from the recessed portion 30, it is necessary to apply a torque large enough to elastically deform surfaces 14c, 14d and/or the engaging protrusion 24, thereby forming a reverse rotation prevention structure.

The reverse rotation prevention structure may also be formed by a separate component from the hydraulically solidified body-embedded reinforcing steel rod 1 and the hydraulically solidified body-embedded reinforcing steel rod joint structure 20. For example, when the hydraulically solidified body-embedded reinforcing steel rod 1 is fixed to the hydraulically solidified body-embedded reinforcing steel rod joint structure 20, the reduced diameter surface 2 of the hydraulically solidified body-embedded reinforcing steel rod 1 faces the large diameter surface 22 of the hydraulically solidified body-embedded reinforcing steel rod joint structure 20, creating a gap between the reduced diameter surface 2 and the large diameter surface 22. Therefore, as shown in Figure 11, the gap between the reduced diameter surface 2 and the large diameter surface 22 may be filled by a rotation prevention member 40 in the shape of a plate with an irregularly shaped perforated outer shape and equipped with spacer portions 42 erected around the holes 44 in a direction approximately perpendicular to the plate surface.

Specifically, the hydraulically solidified body-embedded reinforcing steel rod 1 is inserted through the hole 44 with the tip of the spacer portion 42 facing the hydraulically solidified body-embedded reinforcing steel rod joint structure 20, and the rotation prevention member 40 is brought into contact with or close to the end face of the hydraulically solidified body-embedded reinforcing steel rod joint structure 20, inserting the spacer portion 42 between the reduced diameter surface 2 and the large diameter surface 22 to fill the gap. As a result, even if an attempt is made to rotate the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 so that the rib 4 is relatively displaced in a direction retracting from the recessed portion 30, the spacer portion 42 restricts the relative displacement of the rib 4, i.e., restricts the rotation of the hydraulically solidified body-embedded reinforcing steel rod joint structure 20.

When the rotation prevention member 40 is provided, for example, a nut may be screwed onto the hydraulically solidified body-embedded reinforcing steel rod 1 at a position facing the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 across the rotation prevention member 40 to prevent detachment of the spacer portion 42. The spacer portion 42 may be formed in a wedge shape that is thinner from the base end to the tip end, or the outer surface of the erected surface may be uneven to improve engagement. In this case, a corresponding uneven shape may also be formed on the large-diameter surface of the hydraulically solidified body-embedded reinforcing steel rod joint structure 20.
Furthermore, such anti-rotation members can be applied to conventional hydraulically solidified body-embedded reinforcing steel rods and hydraulically solidified body-embedded reinforcing steel rod joints in which, when the hydraulically solidified body-embedded reinforcing steel rod and the hydraulically solidified body-embedded reinforcing steel rod joint are screwed together, an axial gap occurs between the hydraulically solidified body-embedded reinforcing steel rod and the hydraulically solidified body-embedded reinforcing steel rod joint.

The anti-rotation member 40 may also be configured so that its irregularly shaped outer portion can fit into a receiving portion that can receive an irregular shape provided at the axial end of the hydraulically solidified body-embedded reinforcing steel rod joint structure 20, thereby further preventing relative rotation of the anti-rotation member 40 with respect to the hydraulically solidified body-embedded reinforcing steel rod joint structure 20.

In addition, the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 has a shape in which the recessed portion 26 has an open end 28 so that the rib 4 can be displaced circumferentially and enter the recessed portion 26, but the hydraulically solidified body-embedded reinforcing steel rod joint structure may also be shaped so that the rib 4 fits radially into the recessed portion 26.

Specifically, Figure 12 shows another example of a reinforcing steel bar joint structure 50 for embedded in a hydraulically solidified body, where (a) is a plan view, (b) is a front view, and (c) is an A-A cross-sectional view of (b). The recessed portion 56 of the reinforcing steel bar joint structure 50 for embedded in a hydraulically solidified body has a shape symmetrical about an axis of symmetry parallel to the axial direction, such as a generally elliptical, oval, lip, rugby ball, egg, or diamond shape when viewed in the radial direction. That is, both circumferential ends are closed, and the shape is similar or approximate to the shape of the rib 4 when viewed in the radial direction. Of course, in the reinforcing steel bar joint structure 50 for embedded in a hydraulically solidified body, the rib 4 abuts the inner circumferential surface excluding the large diameter surface 22 and the recessed portion 56.

The hydraulically solidified body-embedded reinforcing steel rod joint structure 50 also has a slit 52, a thin-walled portion 54, and a confirmation hole 58. The slit 52 extends axially at a location 90° out of phase with the recessed portion 56 (where the large-diameter surface 22 is located). The thin-walled portion 54 faces the slit 52 across the axis, and is formed to be elastically deformable so as to expand the internal space by reducing the thickness of a portion of the large-diameter surface 22. The slit 52 and thin-walled portion 54 function as expansion sections for expanding the internal space defined by the inner circumferential surface of the hydraulically solidified body-embedded reinforcing steel rod joint structure 50.

The confirmation hole 58 penetrates the hydraulically solidified body buried reinforcing steel rod joint structure 50 from the inside to the outside, allowing for visual inspection of the interior. The confirmation hole 58 is opened approximately at the center in the axial direction of the hydraulically solidified body buried reinforcing steel rod joint structure 50, and is large enough to allow for visual inspection within at least a specified range along the axial direction.

In the initial state where the thin-walled portion 54 of the hydraulically solidified body-embedded reinforcing steel rod joint structure 50 is not elastically deformed, when the hydraulically solidified body-embedded reinforcing steel rod 1 is inserted and rotated relative to the hydraulically solidified body-embedded reinforcing steel rod 1, causing the rib 4 to displace circumferentially from the position facing the large-diameter surface 22, the inner circumferential surface interferes with the rib 4, restricting relative rotation. At this time, by bending and elastically deforming the thin-walled portion 54 so as to widen the slit 52 along the arrows shown in Figure 13, the diameter of the insertion hole of the hydraulically solidified body-embedded reinforcing steel rod joint structure 50 can be enlarged, and axial interference between the rib 4 of the hydraulically solidified body-embedded reinforcing steel rod 1 and the engaging protrusion of the hydraulically solidified body-embedded reinforcing steel rod joint structure 50 can be alleviated. As a result, the inner circumferential surface and rib 4 do not interfere with each other, allowing the hydraulically solidified body buried reinforcing steel rod joint structure 50 to rotate relative to the hydraulically solidified body buried reinforcing steel rod 1, and the rib 4 fits into the recess 56.

The slits 52 may be formed by cutting out at least a portion of the hydraulically solidified body-embedded reinforcing steel bar joint structure 50 in the circumferential direction, and may be configured as appropriate. For example, dovetail-shaped slits 52 may be provided as shown in Figure 14. The dovetail-shaped slits 52 can restrict the range of expansion of the slits 52. That is, by loosely fitting the convex portions 102 into the dovetail-shaped recesses 100 as shown in Figure 15(a), the convex portions 102 fitted into the recesses 100 can be positioned so as to be displaceable in the circumferential direction, as shown in Figure 15(b), thereby restricting the range of expansion of the slits 52. The expansion range of the slit 52 is restricted to the extent that the mutual contact between the rib 4 of the hydraulically solidified body-embedded reinforcing steel rod 1 and the hydraulically solidified body-embedded reinforcing steel rod joint structure 50 is released during the process of receiving the rib 4, but the rib 4 and the engaging protrusion of the hydraulically solidified body-embedded reinforcing steel rod joint structure 50 remain, preventing complete release. This allows the hydraulically solidified body-embedded reinforcing steel rod 1 and the hydraulically solidified body-embedded reinforcing steel rod joint structure 50 to rotate relative to each other, but prevents them from being pulled out of each other.

Furthermore, the slit 52 expands when the thin section 54 bends, increasing the cross-sectional area of the insertion hole of the hydraulically solidified body-embedded reinforcing steel rod joint structure and expanding the internal space. However, the configuration for expanding the internal space can be designed as appropriate, and multiple radially separable sections may function as expansion sections. However, a separate member or mechanism is required to support the sections together approximately as a single unit and to allow radial and/or circumferential displacement.

Figure 16 shows a partial body 60 that forms part of a reinforcing steel bar joint structure for embedded hydraulic solidified bodies, with (a) being a perspective view and (b) being a view showing the outer surface on the connecting portion side. The partial body 60 has a roughly semi-cylindrical shape obtained by dividing the hydraulic solidified body reinforcing steel bar joint structure in half radially, and a pair of partial bodies 60 constitute the hydraulic solidified body reinforcing steel bar joint structure.

The partial body 60 has a connecting portion 62 with multiple axially arranged rows of recesses 62a and protrusions 62b whose circumferential end faces form dovetail grooves. The partial body 60 also has a recessed portion 56 on its inner circumferential surface. In other words, the inner circumferential surface of the partial body 60 on the connecting portion 62 side forms part of the large diameter surface 22.

Figure 17 is a perspective view showing a hydraulically solidified body-embedded reinforcing steel rod joint structure composed of subassemblies. The subassemblies 60a, 60b can be connected to each other at their connecting portions 62, i.e., by fitting the convex portion of one into the concave portion of the other and vice versa, to form a hydraulically solidified body-embedded reinforcing steel rod joint structure 50. As described above, the hydraulically solidified body-embedded reinforcing steel rod joint structure 50 can set its radial displacement by loosely fitting the convex portion into the dovetail-shaped concave portion. As a result, the subassemblies 60a, 60b can be displaced radially while connected to each other to form the hydraulically solidified body-embedded reinforcing steel rod joint structure 50, allowing the size or diameter of the internal space to be adjusted and expanded.

The hydraulically solidified body-embedded reinforcing steel rod joint structure is not limited to being composed of two sections, but may be composed of three or more sections. Furthermore, the sections may be connected by a separate elastic member, rather than by a connecting section. For example, multiple sections may be arranged in a joint shape and surrounded by an elastic member such as a C-ring or coil spring. Alternatively, an expansion section that expands the internal space of the hydraulically solidified body-embedded reinforcing steel rod joint structure may be provided at two or more suitable locations in the circumferential direction with an elastic section that is elastically deformable in the circumferential direction and extends along the axial direction, allowing for expansion of the diameter. This also allows the sections to be separated radially.

As explained above, by making the recessed portion symmetrical, it is possible to connect a hydraulically solidified body-embedded reinforcing steel rod joint structure and a hydraulically solidified body-embedded reinforcing steel rod, easily position and fix the hydraulically solidified body-embedded reinforcing steel rod joint structure in the desired axial position of the hydraulically solidified body-embedded reinforcing steel rod, improve the connectivity between hydraulically solidified body-embedded reinforcing steel rods, and improve the pull-out strength of the hydraulically solidified body-embedded reinforcing steel rod joint structure and hydraulically solidified body-embedded reinforcing steel rod when embedded in the solidified hydraulic body. Furthermore, if the recessed portion is symmetrical, after fitting the rib into the recessed portion, relative rotation of the hydraulically solidified body-embedded reinforcing steel rod joint structure with the hydraulically solidified body-embedded reinforcing steel rod is restricted, preventing the rib from coming off the recessed portion. As a result, the connection between the hydraulically solidified body buried reinforcing steel rod joint structure and the hydraulically solidified body buried reinforcing steel rod can be made stronger.

The external shape of the hydraulically solidified body-embedded reinforcing steel rod joint structure is not particularly limited, but it is preferable for it to have at least a two-sided shape to facilitate the application of torque for relative rotation to the hydraulically solidified body-embedded reinforcing steel rod. Furthermore, hydraulically solidified body-embedded reinforcing steel rod joint structures, such as the hexagonal cylindrical hydraulically solidified body-embedded reinforcing steel rod joint structure 20 shown in Figure 18, may have a polygonal external shape, including a star shape. Of course, the hydraulically solidified body-embedded reinforcing steel rod joint structure may be cylindrical with a two-sided shape along a portion of the axial direction, or may have a polygonal shape along only a portion of the axial direction.

The confirmation hole 58 may also have a center position indication means for indicating the longitudinal center of the hydraulically solidified body-embedded reinforcing steel rod joint structure. Specifically, as shown in FIG. 18 , a constricted portion 58a is provided with a narrower opening at a location roughly corresponding to the axial center of the hydraulically solidified body-embedded reinforcing steel rod joint structure. This makes it possible to visually confirm the position of each hydraulically solidified body-embedded reinforcing steel rod when inserting a hydraulically solidified body-embedded reinforcing steel rod into each end of the hydraulically solidified body-embedded reinforcing steel rod joint structure, and simultaneously and easily determine the position of each hydraulically solidified body-embedded reinforcing steel rod relative to the axial center of the hydraulically solidified body-embedded reinforcing steel rod joint structure.

Now, with reference to Figure 19, we will explain the connection of two hydraulically solidified body-embedded reinforcing steel rods 1a, 1b using a hydraulically solidified body-embedded reinforcing steel rod joint structure 20. First, a hydraulically solidified body-embedded reinforcing steel rod 1a is inserted into one axial end of the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 shown in Figure 19(a), and the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 is displaced toward the hydraulically solidified body-embedded reinforcing steel rod 1a. At this time, the large diameter surface 22 on the inner circumferential surface of the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 faces the rib 4 of the hydraulically solidified body-embedded reinforcing steel rod 1a.

The axial position of the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 relative to the hydraulically solidified body-embedded reinforcing steel rod 1a is set so that the other axial end face of the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 is approximately flush with the axial end face of the hydraulically solidified body-embedded reinforcing steel rod 1a or so that this end face is slightly exposed to the outside. The hydraulically solidified body-embedded reinforcing steel rod joint structure 20 is rotated a small angle clockwise as shown by the arrow in Figure 19(b), i.e., rotated relative to the hydraulically solidified body-embedded reinforcing steel rod 1a so that the rib 4 fits somewhat into the recessed portion 26, and then temporarily fastened.

The hydraulically solidified body-embedded reinforcing steel rod joint structure 20 is aligned with the hydraulically solidified body-embedded reinforcing steel rod 1b, and the phases of the ribs of the hydraulically solidified body-embedded reinforcing steel rod 1a and the hydraulically solidified body-embedded reinforcing steel rod 1b temporarily fastened to the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 are aligned. The other end of the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 is then brought adjacent to the end face of the hydraulically solidified body-embedded reinforcing steel rod 1b, and the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 is released from its temporary fastening to the hydraulically solidified body-embedded reinforcing steel rod 1a. In other words, the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 is rotated counterclockwise relative to the hydraulically solidified body-embedded reinforcing steel rod 1a, allowing for relative axial displacement.

Next, the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 is displaced axially relative to the hydraulically solidified body-embedded reinforcing steel rod 1a so that the hydraulically solidified body-embedded reinforcing steel rod 1b is inserted into the other axial end of the hydraulically solidified body-embedded reinforcing steel rod joint structure 20. That is, the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 is displaced toward the hydraulically solidified body-embedded reinforcing steel rod 1b so that the hydraulically solidified body-embedded reinforcing steel rod 1b is inserted into the hydraulically solidified body-embedded reinforcing steel rod joint structure 20. As a result, as shown in Figure 19(c), the hydraulically solidified body-embedded reinforcing steel rod 1b can be inserted into the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 by displacing it relative to the hydraulically solidified body in the opposite direction to the insertion of the hydraulically solidified body-embedded reinforcing steel rod 1a.

At this time, as shown in Figure 19 (c), confirmation holes 58 are provided on the outer periphery of the hydraulically solidified body-embedded reinforcing steel rod joint structure 20, and the positions of the ends of the hydraulically solidified body-embedded reinforcing steel rods 1a, 1b can be determined through the confirmation holes 58. Furthermore, the position of the axial center can be determined by the constricted portions 58a of the confirmation holes 58, making it possible to determine the axial positions of each hydraulically solidified body-embedded reinforcing steel rod 1a, 1b within the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 with a fairly high degree of accuracy.

Then, as shown in Figure 19(d), by rotating the hydraulically solidified body-embedded reinforcing steel rod joint structure 20 clockwise relative to the hydraulically solidified body-embedded reinforcing steel rods 1a, 1b, the hydraulically solidified body-embedded reinforcing steel rods 1a, 1b can be connected via the hydraulically solidified body-embedded reinforcing steel rod joint structure 20.

The concave portions of the hydraulically solidified body buried reinforcing steel bar joint structure have been described as being asymmetric or symmetrical. However, it is of course possible to arrange asymmetric and symmetrical concave portions in a row in the axial direction. In this case, the arrangement of the concave portions may be such that asymmetric and symmetrical concave portions alternate, or a hybrid structure may be used in which a symmetrical concave portion is arranged every few asymmetrical concave portions, or in other appropriate combinations.

Of course, the recessed portion is not limited to a non-helical shape such as an asymmetrical or symmetrical shape, and may be helical. Furthermore, the helical shape may extend continuously, or may be a series of approximately helical recessed portions intermittently arranged along a virtual helical path. A rib may be fitted into the helical recessed portion to relatively displace the rib along the helical direction. In this case, the helical shape is configured as a so-called right-handed helical groove, in which the inner circumferential surface of the recessed portion can slide against the surfaces 14a and 14d of the rib 4, thereby guiding the direction of displacement of the rib 4. Needless to say, the inner circumferential surface of the recessed portion may also be configured as a so-called left-handed helical groove, in which the inner circumferential surface of the recessed portion slides against the surfaces 14b and 14c, thereby guiding the direction of displacement of the rib 4. As a result, the hydraulically solidified body-embedded steel rod reinforcing joint structure can be displaced axially by relative rotation with respect to the hydraulically solidified body-embedded steel rod.
In addition, when the concave portion has a spiral shape, the shape of the radial end of the engaging protrusion can be set appropriately, and can be set to, for example, a planar shape, a convex curved shape, an acute angle shape, a pointed shape, etc. Furthermore, the spiral groove shape of the concave portion can be set appropriately, for example, by configuring the width shape of the groove to narrow gradually or in steps from one end to the middle in the axial direction.

The hydraulically solidified body-embedded reinforcing steel rod joint structure may have both a non-helical recessed portion and a helical recessed portion. Figure 20 shows a hydraulically solidified body-embedded reinforcing steel rod joint structure 70 having a non-helical recessed portion and a helical recessed portion, where (a) is a perspective view, (b) is a front view, and (c) is an A-A cross-sectional view of (b). The hydraulically solidified body-embedded reinforcing steel rod joint structure 70 has a non-helical recessed portion 72a at one end and a helical recessed portion 72b at the other end, with the boundary being midway in the axial direction.
Of course, in such a hybrid structure of recesses, the boundary between the non-helical region and the helical region may be directly connected or may have an appropriate gap therebetween.

The hydraulically solidified body-embedded reinforcing steel rod joint structure 70 also has engagement holes 74 at both ends. The engagement holes 74 are located at the ends of the insertion holes of the hydraulically solidified body-embedded reinforcing steel rod joint structure 70, and have a tapered inner circumferential surface that widens toward the opening. A flat knurling is formed along the axial direction on the inner circumferential surface of the engagement hole 74. The engagement hole 74 is designed to have a larger diameter than the insertion hole of the hydraulically solidified body-embedded reinforcing steel rod joint structure 70, so that a relative rotation prevention member 80 (described later) can be interposed between the engagement hole 74 and the hydraulically solidified body-embedded reinforcing steel rod 1.

Note that although the engagement hole 74 here is tapered, it does not necessarily have to be tapered and may be straight, curved, or curved. However, a tapered shape is preferable when attempting to accommodate dimensional errors, etc.

Figure 21 shows a relative rotation prevention member 80 that engages with the hydraulically solidified body-embedded reinforcing steel rod joint structure 70, with (a) being a perspective view, (b) being a side view, and (c) being a cross-sectional view. The relative rotation prevention member 80 has a roughly ring-shaped main body 82 and a flange 84. Note that while the flange 84 is shown here, this is not necessarily required. The relative rotation prevention member 80 also has an inner circumferential surface 86 that surrounds the hydraulically solidified body-embedded reinforcing steel rod 1.

The main body 82 has an outer shape that can engage with the engagement hole 74. That is, the outer peripheral surface of the main body 82 has a tapered shape that gradually reduces in diameter from the flange 84 side, corresponding to the inner peripheral surface of the engagement hole 74. In addition, a flat knurling is formed on the outer peripheral surface of the main body 82 along the axial direction. Note that the outer peripheral shape of the main body 82 is not limited to a tapered shape, and can be set to a straight shape, a curved shape, a curved line shape, etc., and is preferably a shape that corresponds to the engagement hole 74.
Furthermore, the flat knurling along the axial direction is not necessarily limited to a flat shape, and can be set as appropriate as long as it can engage with the anti-rotation means provided in the engagement hole 74 to prevent relative rotation.

The flange portion 84 has a larger outer diameter than the main body portion 82, and multiple irregularities 84a are formed circumferentially on its axial end face. These irregularities 84a preferably have a sawtooth shape, and are preferably set so that the direction in which the irregularities 84a extend, i.e., the direction in which the ridges extend, is aligned with the radial direction of the relative rotation prevention member 80. As a result, the irregularities 84a on the end face of the flange portion 84 extend radially from the axis.

The inner circumferential surface 86 is composed of a pair of interference surfaces 86a that can interfere with the rib 4 without contacting the reduced diameter surface 2 of the hydraulically solidified body-embedded reinforcing steel rod 1, and a pair of non-contact surfaces 86b that face the rib 4 at a distance. That is, the interference surfaces 86a and non-contact surfaces 86b of the inner circumferential surface 86 are arranged alternately along the circumferential direction. That is, the hole defined in the inner circumferential surface 86 can function as a non-circular hydraulically solidified body-embedded reinforcing steel rod insertion hole whose shape in the axial direction roughly corresponds to the axial outer shape of the hydraulically solidified body-embedded reinforcing steel rod 1.

When interposed between the hydraulically solidified body-embedded reinforcing steel rod joint structure 70 and the hydraulically solidified body-embedded reinforcing steel rod 1, the relative rotation prevention member 80 can restrict the hydraulically solidified body-embedded reinforcing steel rod joint structure 70 from rotating relative to the hydraulically solidified body-embedded reinforcing steel rod 1. Specifically, the relative rotation prevention member 80 is placed in advance so that it surrounds the outer periphery of the hydraulically solidified body-embedded reinforcing steel rod 1. At this time, the hydraulically solidified body-embedded reinforcing steel rod 1 fits into the hydraulically solidified body-embedded reinforcing steel rod insertion hole in a state that prevents relative rotation.

Next, a hydraulically solidified body-embedded reinforcing steel rod 1 is inserted into both ends of the hydraulically solidified body-embedded reinforcing steel rod joint structure 70, and the ribs 4 are fitted into the recessed portions 72a and 72b. The relative rotation prevention member 80 is inserted into the engagement hole 74 by sliding axially toward the hydraulically solidified body-embedded reinforcing steel rod joint structure 70. The flat knurling on the main body 82 then engages circumferentially with the flat knurling in the engagement hole 74 of the hydraulically solidified body-embedded reinforcing steel rod joint structure 70. In other words, the concave and convex portions of the flat knurling align with each other and engage circumferentially.

As a result, the relative rotation prevention member 80 circumferentially engages with both the hydraulically solidified body-embedded reinforcing steel rod 1 and the hydraulically solidified body-embedded reinforcing steel rod joint structure 70. That is, the flat knurling on the outer periphery of the main body 82 circumferentially engages with the flat knurling in the engagement hole 74. Meanwhile, when the interference surface 86a of the inner circumferential surface 86 is displaced circumferentially from the position facing the reduced diameter surface 2 of the hydraulically solidified body-embedded reinforcing steel rod 1, it interferes with the rib 4, resulting in the inner circumferential surface 86 engaging circumferentially with the hydraulically solidified body-embedded reinforcing steel rod 1.

Next, Figure 22 shows a relative displacement prevention member 90, with (a) being a perspective view, (b) being a side view, and (c) being a cross-sectional view. The relative displacement prevention member 90 is a hollow member with a roughly hexagonal outer shape and a hole 90a that can surround the hydraulically solidified body-buried reinforcing steel rod 1, and has a continuous spiral groove 92 on its inner circumferential surface. The relative displacement prevention member 90 also has a flange-shaped end, and multiple uneven portions 94 are formed along the circumferential direction on one end face in the axial direction. The uneven portion 94 is configured to be undulating in an appropriate shape that can engage with the uneven portions 84a of the flange portion 84, but in this case it is configured to be saw-tooth shaped and extend radially from the axis.

Therefore, where the relative rotation prevention member 80 and the relative displacement prevention member 90 come into contact, the unevenness 84a and unevenness portion 94 function as a relative rotation prevention mechanism that prevents relative rotation between the two members 80, 90.

The spiral direction of the spiral groove portion 92 is set so that it can fit over the rib 4 of the reinforcing steel rod 1 for embedding in a hydraulically solidified body. Of course, the spiral direction can be set as appropriate, but here the spiral direction of the spiral groove portion 92 is set to a left-handed spiral, opposite the spiral of the recessed portion 72b. By fitting the rib 4 into the spiral groove portion 92, it engages with the rib 4 and restricts axial displacement, but when the relative displacement prevention member 90 itself is rotated, it can be displaced axially relative to the reinforcing steel rod 1 for embedding in a hydraulically solidified body.

The following describes the connection between the hydraulically solidified body-embedded reinforcing steel rod joint structure 70 and the hydraulically solidified body-embedded reinforcing steel rod 1 using a rigid connection structure that combines the above-mentioned relative rotation prevention member 80 and relative displacement prevention member 90. Two hydraulically solidified body-embedded reinforcing steel rods 1a and 1b are inserted into the hydraulically solidified body-embedded reinforcing steel rod joint structure 70, with the rib 4 of one hydraulically solidified body-embedded reinforcing steel rod 1a fitting into the recessed portion 72a, and the rib 4 of the other hydraulically solidified body-embedded reinforcing steel rod 1b fitting into the right-handed spiral recessed portion 72b.

In this case, the other hydraulically solidified body-embedded reinforcing steel rod 1b is connected first. Specifically, the hydraulically solidified body-embedded reinforcing steel rod 1b is positioned in the opening at the other end (the upper end in Figure 23) of the hydraulically solidified body-embedded reinforcing steel rod joint structure 70, and the recessed portion 72b is aligned so that it can fit into the rib 4. Next, as shown in Figure 23(a), when the hydraulically solidified body-embedded reinforcing steel rod joint structure 70 is rotated clockwise relative to the hydraulically solidified body-embedded reinforcing steel rod 1b, the hydraulically solidified body-embedded reinforcing steel rod 1b is displaced relative to the hydraulically solidified body-embedded reinforcing steel rod joint structure 70. That is, as the hydraulically solidified body embedded reinforcing steel rod joint structure 70 rotates, the rib 4 fitted into the recessed portion 72b is guided in the direction of the spiral, resulting in relative displacement of the hydraulically solidified body embedded reinforcing steel rod 1b in the direction along the spiral, moving to the innermost position along the recessed portion 72b.

Next, one of the hydraulically solidified body-embedded reinforcing steel rods 1a is connected. Specifically, as shown in Figure 23(b), the hydraulically solidified body-embedded reinforcing steel rod 1a is inserted into the insertion hole from one axial end of the hydraulically solidified body-embedded reinforcing steel rod joint structure 70, while checking the depth position of the hydraulically solidified body-embedded reinforcing steel rod 1a using the confirmation hole 58. At this time, the reduced diameter surface 2 of the hydraulically solidified body-embedded reinforcing steel rod 1a is aligned with the recessed portion 72a of the hydraulically solidified body-embedded reinforcing steel rod joint structure 70. Then, as shown in Figure 23(c), by rotating the hydraulically solidified body-embedded reinforcing steel rod joint structure 70 counterclockwise relative to the hydraulically solidified body-embedded reinforcing steel rod 1a by a predetermined angle, in this case approximately 90°, the rib 4 enters and fits into the recessed portion 72a, and the hydraulically solidified body-embedded reinforcing steel rod joint structure 70 and the hydraulically solidified body-embedded reinforcing steel rod 1a are axially engaged.

Next, the relative rotation prevention member 80 is installed. Specifically, as shown in Figure 24(a), the relative rotation prevention member 80, which has been inserted in advance into the hydraulically solidified body-embedded reinforcing steel rod 1a (1b), is slid toward the hydraulically solidified body-embedded reinforcing steel rod joint structure 70 while still surrounding the hydraulically solidified body-embedded reinforcing steel rod 1a (1b), and inserted into the engagement hole 74.
Furthermore, the relative displacement prevention member 90, which has been screwed leftward onto the hydraulically solidified body-embedded reinforcing steel rod 1a (1b) prior to the relative rotation prevention member 80, is rotated in a direction that advances toward the relative rotation prevention member 80, i.e., leftward relative to the hydraulically solidified body-embedded reinforcing steel rod 1a (1b). As a result, the irregularities 84a on the end surface of the flange portion 84 and the irregularities 94 come close to each other and come into contact with each other, so that the irregularities engage with each other.

By combining the relative rotation prevention member 80 and the relative displacement prevention member 90 in this manner, the hydraulically solidified body-embedded reinforcing steel rod 1 and the hydraulically solidified body-embedded reinforcing steel rod joint structure 70 can be more firmly connected. That is, the inner periphery of the relative rotation prevention member 80 circumferentially engages with the hydraulically solidified body-embedded reinforcing steel rod 1, and the outer periphery circumferentially engages with the hydraulically solidified body-embedded reinforcing steel rod joint structure 70. Therefore, when one of the hydraulically solidified body-embedded reinforcing steel rod joint structure 70 and the hydraulically solidified body-embedded reinforcing steel rod 1 rotates relative to the other, the rotation is restricted by the relative rotation prevention member 80. This allows the rib 4 to be firmly maintained engaged with the recessed portions 72a, 72b. Furthermore, because the relative displacement prevention member 90 is positioned axially outboard of the relative rotation prevention member 80, it is possible to reliably prevent the relative rotation prevention member 80 from coming out of the engagement hole 74 in the axial direction.

In addition, while the relative displacement prevention member 90 can easily displace circumferentially relative to the hydraulically solidified body-embedded reinforcing steel rod 1, the circumferential engagement between the flange portion 84 and the uneven portion 94 prevents the relative displacement prevention member 90 from rotating in a direction that could separate it from the hydraulically solidified body-embedded reinforcing steel rod joint structure 70, firmly fixing the relative rotation prevention member 80 and the relative displacement prevention member 90 together. Therefore, the hydraulically solidified body-embedded reinforcing steel rod joint structure 70, the relative rotation prevention member 80, and the relative displacement prevention member 90 can be substantially integrated and very firmly connected to the hydraulically solidified body-embedded reinforcing steel rod 1, eliminating the need for the injection of fluid hardening fillers, etc., which was previously required.

The above-mentioned confirmation hole may be blocked with a light-transmitting material such as a transparent film or a transparent resin material, as long as it allows at least the hydraulically solidified body-buried reinforcing steel rod inside the hydraulically solidified body-buried reinforcing steel rod joint structure to be seen.

Although the main body of the relative rotation prevention member 80 is cylindrical, it may be shaped so as to be elastically deformable in the radial direction. For example, as shown in FIG. 25 , slits 87 extending along the axial direction may be formed in the main body 82. The slits 87 may be formed at predetermined intervals along the circumferential direction, or as shown in FIG. 25( b), the slits 87 may be formed by cutting out a portion of the non-contact surface 86 b along the axial direction. Furthermore, the slits 87 may be formed so as to extend widely in the circumferential direction of the main body 82 as shown in FIG. 25( c), and the size and number of the slits may be set as appropriate.
By forming such slits 87, the main body 82 can elastically and/or plastically deform so as to bend inward, thereby more firmly adhering to the steel rod 1 for embedded in a hydraulically solidified body. That is, the slits 87 cause the outer circumferential surface of the main body 82 to be intermittently separated in the circumferential direction, making each portion more susceptible to elastic and/or plastic deformation. Furthermore, when the main body 82 elastically and/or plastically deforms radially inward, the inner circumferential surface of the main body 82 closely contacts the outer circumferential surface of the steel rod 1 for embedded in a hydraulically solidified body and presses it radially inward. As a result, the relative rotation prevention member 80 can be more firmly fixed to the steel rod 1 for embedded in a hydraulically solidified body. Furthermore, although the outer circumferential surface of the main body 82 has a tapered shape corresponding to the inner circumferential surface of the engagement hole 74, it may also have a different tapered shape from the engagement hole 74 so that it is pressed radially inward by the inner circumferential surface of the engagement hole 74. Specifically, if the taper angle is slightly gentler than that of the engagement hole 74 and the outer diameter of the axial tip of the main body portion 82 is designed to exceed the inner diameter of the innermost part of the engagement hole 74, the main body portion 82 will gradually be pressed against the inner surface of the engagement hole 74 as it enters the engagement hole 74, and will reliably elastically deform radially inward to firmly adhere to the hydraulically solidified body-buried reinforcing steel rod 1.

Furthermore, the joint structure of a steel rod for reinforcing a hydraulically solidified body embedded in a reinforcement may be configured to allow the insertion of a steel rod for reinforcing a hydraulically solidified body embedded in a reinforcement with different diameters at one end and both ends in the axial direction. In other words, the joint structure of a steel rod for reinforcing a hydraulically solidified body embedded in a reinforcement may be configured to connect steel rods for reinforcing a hydraulically solidified body embedded in a reinforcement with different diameters, in which case the cross-sectional area and diameter of a first range extending from one end to the middle of the axial direction may be configured to be different from the cross-sectional area and diameter of a second range extending from the other end to the middle of the axial direction.

Furthermore, the hydraulically solidified body-embedded reinforcing steel rod joint structure is not limited to one made up of a single member, but may be made up of multiple members. For example, as shown in Figure 26, a hydraulically solidified body-embedded reinforcing steel rod joint structure 130 may be made up of two axially separated cylindrical members 110, 120.
The cylindrical member 110 has an opening at one axial end through which the hydraulically solidified body buried reinforcing steel rod 1 can be inserted, and a connecting portion 112 consisting of a spiral groove is arranged on the outer circumferential surface of the other end. Also, as shown in Figure 26(b), the inner circumferential surface of the cylindrical member 110 is arranged with large diameter surfaces 22 arranged at positions facing each other across the axis, and an engaging protrusion 24 and a recess 26 adjacent to the large diameter surface 22 in the circumferential direction.

The cylindrical member 120 has an opening at one end in the axial direction through which the hydraulically solidified body buried reinforcing steel rod 1 can be inserted, and has an enclosing portion 122 at the other end. The enclosing portion 122 has a large diameter so that its inner circumferential surface can enclose the connecting portion 112, and a spiral convex portion that extends spirally and fits into the spiral groove of the connecting portion 112 is provided on its inner circumferential surface.
The inner peripheral surface of the cylindrical member 110 is also provided with a large diameter surface 22 arranged at positions facing each other across the axis, and an engaging protrusion 24 and a recess 26 adjacent to the large diameter surface 22 in the circumferential direction.

The tubular members 110, 120 are connected by threading the connecting portion 112 into the surrounding portion 122 to form a hydraulically solidified body buried reinforcing steel rod joint structure 130 (see Figure 27). Of course, the structure connecting the tubular members 110, 120 is not limited to this, and it is sufficient that the tubular members 110, 120 are connected so that they can rotate relative to each other and that relative axial displacement is restricted. It goes without saying that they can also be connected using a third member, for example.

By constructing this type of hydraulically solidified body-embedded reinforcing steel rod joint structure 130, it is possible to absorb connection imperfections caused by phase misalignment between the hydraulically solidified body-embedded reinforcing steel rods 1, 1 when inserting the hydraulically solidified body-embedded reinforcing steel rods 1, 1 into both ends in the axial direction. In other words, if the positions of the ribs 4 differ between the hydraulically solidified body-embedded reinforcing steel rods 1, 1, even if the rib 4 of one hydraulically solidified body-embedded reinforcing steel rod 1 is fitted into the recessed portion 26, there is a risk that the rib 4 of the other hydraulically solidified body-embedded reinforcing steel rod 1 will not fit into the recessed portion 26. This can be absorbed and prevented. Specifically, by rotating either one of the cylindrical members 110, 120 through at least a small angle (less than 90°), both cylindrical members 11, 120 can reliably fit the rib 4 of the inserted hydraulically solidified body buried reinforcing steel rod 1 into the recessed portion 26.

1... Steel rod for reinforcing a type of hydraulically solidified body to be buried 2... Reduced diameter surface 4... Rib 4a... End surface 6... Concave diameter surface 10... Tip portion 12... Ridge line 14a-14d... Surface 20... Joint structure of steel rod for reinforcing a type of hydraulically solidified body to be buried 22... Large diameter surface 24... Engaging convex portion 26... Concave portion 28, 32... Open end 29... Stopper 40... Rotation prevention member 42... Spacer portion 44... Hole 52... Slit 58... Confirmation hole 60... Partial body 74... Engaging hole 80... Relative rotation prevention member 82... Main body portion 84... Flange portion 90... Relative displacement prevention member 92... Spiral groove portion 94... Concave and concave portion.

Claims (25)

A joint structure for a steel rod for reinforcing a hydraulically solidified body embedded in a reinforcement has an insertion hole through which a steel rod for reinforcing a hydraulically solidified body embedded in a reinforcement direction can be inserted in an axial direction, and an inner periphery of the insertion hole is engaged with a rib of the steel rod for reinforcing a hydraulically solidified body to connect the steel rod for reinforcing a hydraulically solidified body embedded in a reinforcement direction,
engaging projections arranged in a row in the axial direction on the inner periphery and capable of engaging with the ribs;
at least one or more types of non-helical recessed portions alternate with the engaging protrusions in the axial direction and are recessed so that the ribs can be fitted therein;
a large diameter surface that is circumferentially adjacent to the engaging protrusion and the recess, and that does not engage with the rib;
The concave portion has a hybrid structure in which the non-helical shape has a symmetric shape and an asymmetric shape with the axial direction as an axis of symmetry when viewed in the radial direction, and is arranged in a row in the axial direction, and the symmetric shapes and the asymmetric shapes are arranged,
A joint structure for a steel rod for reinforcing a hydraulically solidified body to be buried, characterized in that the rib is fitted into the recessed portion to restrict axial displacement of the steel rod for reinforcing a hydraulically solidified body to be buried. A joint structure for a steel rod for reinforcing a hydraulically solidified body embedded in a reinforcement has an insertion hole through which a steel rod for reinforcing a hydraulically solidified body embedded in a reinforcement direction can be inserted in an axial direction, and an inner periphery of the insertion hole is engaged with a rib of the steel rod for reinforcing a hydraulically solidified body to connect the steel rod for reinforcing a hydraulically solidified body embedded in a reinforcement direction,
engaging projections arranged in a row in the axial direction on the inner periphery and capable of engaging with the ribs;
at least one type of recessed portion alternately arranged with the engaging protrusions in the axial direction and recessed so that the rib can be fitted therein;
a large diameter surface that is circumferentially adjacent to the engaging protrusion and the recess, and that does not engage with the rib;
The insertion hole has a substantially oval or elliptical hole shape when viewed in the axial direction,
A joint structure for a steel rod for reinforcing a hydraulically solidified body to be buried, characterized in that the rib is fitted into the recessed portion to restrict axial displacement of the steel rod for reinforcing a hydraulically solidified body to be buried. The symmetrical shape has closed ends at both ends in the circumferential direction,
The main body of the hydraulically solidified body buried type reinforcing steel rod joint structure has an expansion part that allows the internal space to be expanded,
The hydraulically solidified body-buried reinforcing steel rod joint structure according to claim 1, characterized in that the expansion portion is capable of transitioning between a state in which the rib is received on the inner circumference and a state in which the insertion hole is expanded to receive the rib on the inner circumference . 4. The hydraulically solidified body buried reinforcing steel bar joint structure according to claim 3, wherein the expansion portion has an elastic deformation mechanism and/or a radial separation mechanism. The hydraulically solidified body-buried reinforcing steel rod joint structure according to claim 1, characterized in that the asymmetrically shaped concave portion has an open end at one circumferential end, and can receive the rib from the open end side. A hydraulically solidified body-buried reinforcing steel rod joint structure as described in claim 5, characterized in that the other circumferential end of the asymmetrically shaped concave portion is a closed end, and the closed end can regulate the circumferential displacement of the rib. The recessed portion has a spiral shape,
3. A hydraulically solidified body-buried reinforcing steel bar joint structure according to claim 2, wherein the radial end of said engaging projection is formed in a planar shape, a convex curved shape or an acute angle shape. The hydraulically solidified body buried reinforcing steel rod joint structure according to claim 7, characterized in that the spiral-shaped concave portion is formed continuously or intermittently along a virtually set spiral path. A hydraulically solidified body-buried reinforcing steel rod joint structure as described in claim 7, characterized in that the spiral-shaped concave portion is formed continuously and the width of the concave portion gradually or stepwise narrows from one end to the middle of the axial direction. A hydraulically solidified body-embedded reinforcing steel rod joint structure according to any one of claims 1 to 9, characterized in that the insertion hole has a hole shape, when viewed in the axial direction, that is approximately similar or approximate to the outer shape of the hydraulically solidified body-embedded reinforcing steel rod when viewed in the axial direction. The hydraulically solidified body buried reinforcing steel rod joint structure according to claim 10, characterized in that the insertion hole has a two-sided width portion, and the opposing ends of the opposing two-sided width portion are connected by an inner surface that forms a convex arc with a predetermined radius of curvature. A hydraulically solidified body-buried reinforcing steel bar joint structure as described in any one of claims 1 to 11, characterized in that the cross-sectional area of the insertion hole is different between a first range from one end to the middle part in the axial direction and a second range from the other end to the middle part in the axial direction . A hydraulically solidified body buried reinforcing steel rod joint structure as described in claim 2, characterized in that the concave portion from one end to the middle portion in the axial direction is spirally shaped, and the concave portion from the other end to the middle portion is non- spirally shaped. A hydraulically solidified body-buried reinforcing steel rod joint structure as described in any one of claims 1 to 13, characterized in that a relative rotation prevention member is provided at at least one axial end to prevent relative rotation with the hydraulically solidified body-buried reinforcing steel rod. A hydraulically solidified body-buried reinforcing steel rod joint structure as described in any one of claims 1 to 13, characterized in that a relative displacement prevention member is provided at at least one axial end to prevent relative axial displacement with the hydraulically solidified body-buried reinforcing steel rod. A rigid structure is provided at the axial end,
A hydraulically solidified body-embedded reinforcing steel rod joint structure as described in any one of claims 1 to 13, characterized in that the rigid connection structure has a relative rotation prevention member that prevents relative rotation with the hydraulically solidified body-embedded reinforcing steel rod and a relative displacement prevention member that prevents relative displacement with respect to the hydraulically solidified body- embedded reinforcing steel rod. 17. A joint structure for a steel rod for reinforcing a hydraulically solidified body buried type according to claim 14 or 16, wherein the relative rotation prevention member surrounds the hydraulically solidified body buried type reinforcing steel rod and is inserted into the engagement hole. The relative rotation prevention member has an engagement surface that engages with an inner periphery of the engagement hole;
a non-circular steel rod insertion hole for reinforcing a hydraulically solidified body that is substantially equivalent to the outer shape of the steel rod for reinforcing a hydraulically solidified body when viewed in the axial direction;
A hydraulically solidified body-embedded reinforcing steel rod joint structure according to claim 14, 16 or 17, characterized in that the hydraulically solidified body-embedded reinforcing steel rod can be fitted into the hydraulically solidified body-embedded reinforcing steel rod insertion hole in a state where it cannot rotate relative to the hydraulically solidified body, and the engagement surface engages with the inner circumference of the engagement hole. 17. A hydraulically solidified body-buried reinforcing steel rod joint structure according to claim 15 or 16, characterized in that the relative displacement prevention member engages with a rib of the hydraulically solidified body-buried reinforcing steel rod, thereby restricting axial displacement. The hydraulically solidified body-buried reinforcing steel rod joint structure according to claim 15, 16 or 19, characterized in that the relative displacement prevention member has a hole portion through which the hydraulically solidified body-buried reinforcing steel rod can be inserted and which has a spiral groove on its inner surface. A hydraulically solidified body buried reinforcing steel rod joint structure as described in claim 16, characterized in that a relative rotation prevention mechanism is provided at the abutment portion between the relative rotation prevention member and the relative displacement prevention member to prevent relative rotation between the relative rotation prevention member and the relative displacement prevention member. A hydraulically solidified body-buried reinforcing steel rod joint structure as described in any one of claims 1 to 21, characterized in that at an appropriate intermediate position in the longitudinal direction of the main body, there is provided a confirmation hole penetrating from the inside to the outside, which allows the insertion depth of the hydraulically solidified body-buried reinforcing steel rod to be visually confirmed . 23. The hydraulically solidified body buried reinforcing steel bar joint structure according to claim 22, wherein the confirmation hole has a center position indicating means for indicating the center portion in the longitudinal direction. The hydraulically solidified body buried reinforcing steel rod joint structure according to claim 23, characterized in that the confirmation hole has a constricted portion in which the hole shape is constricted at a point corresponding to the center of the longitudinal direction, and the constricted portion forms the center position indication means. 25. The hydraulically solidified body buried reinforcing steel bar joint structure according to claim 22, wherein the confirmation hole is closed with a light-transmitting member.