JPH09144489A - Connecting metal fitting for concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase strength, by which concrete is joined, by disposing the front end faces of the fixing reinforcements of female metal fittings to the inside section of a concrete-mating end face from root section and pressing the female fitting and the female fitting consisting of an iron casting into a wedge type male metal fitting. SOLUTION: Fixing reinforcements 6 are projected from the upper sections of the center lines of the rear sections of the mating end faces of female metal fitting bodies 4, and front end sections, on which reinforcing ribs are mounted, which are bent in an approximately L shape and on which fixing flanges are installed, are disposed on the concrete internal side. The shapes of the female fitting bodies 4, into which an H-shaped sectional male fitting 3, in which grades are formed for displaying a wedge effect in internal surfaces 17, is pressed, are formed in a C-shaped cross section, and saw-tooth shaped hubs 10 and fitted onto joint surfaces, thus plastically deforming the front ends of blade sections at the time of pressing-in, then firmly connecting the blade sections. Accordingly, the number of the fixing reinforcements used in the female fittings is reduced, and the shapes of the fittings are simplified and fixing strength can be increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joining member for a concrete member used for a foundation concrete for civil engineering and construction, a support work segment used for a shield tunnel, a box culvert and the like.

[0002]

2. Description of the Related Art Basic concrete for civil engineering and construction is generally formed by constructing a temporary frame at a construction site, pouring the concrete into it, and after solidifying the concrete, disassembling and removing the temporary frame. Then, a method of forming concrete members of a certain size in advance at a concrete factory and lining up and joining the concrete members at the construction site has begun to be adopted.

On the other hand, in tunnel construction, etc., the segments are modularized and manufactured in advance at a concrete factory, and at the construction site, the segments are arranged at prescribed positions in accordance with the excavation of the tunnel excavator, and after assembling in sequence, via bolts and nuts, etc. It is screwed and fastened.

In a further improved joining fitting, Japanese Patent Publication No. 6-
As disclosed in Japanese Patent No. 72519, a segment coupling mechanism employing a wedge-shaped metal fitting has also been developed.

For example, there is a coupling mechanism as shown in FIG. FIG. 6 is a perspective view showing the configuration of the entire joining fitting before joining. The female metal fitting 31 to which the fixing rebar 30 has been fastened in advance is embedded in the mating end surface of the concrete member (not shown), and the female metal fitting 31 to which the fixing rebar 30 has already been fastened also to the mating end surface of another concrete member. Is buried. At the construction site, these concrete members are arranged at prescribed positions, and the male metal fitting 33 is press-fitted into the slit 32 provided in the female metal fitting 31, so that through the wedge portion 34 provided in the male metal fitting 33. It is the one to combine.

A plurality of fixing rebars 30 are fastened to the female metal fitting 31 in order to secure the fixing strength with the concrete member. Further, the size of the female fitting 31 is secured so that the plurality of fixing rebars 30 are fastened.

Furthermore, in order to ensure the connection between the female metal fitting 31 and the male metal fitting 33, the female metal fitting 31 has a male metal fitting 33.
Slit 32 for press-fitting wedge portion 34 provided in
However, it is provided with a dimensional accuracy in a shape that fits on the wedge surface.

[0008]

The position of the female metal fitting 31 to be embedded in the concrete member for connection is provided near the end face of the concrete member because the work of press-fitting the male metal fitting 33 is required. In order to secure the strength that the concrete firmly anchors the anchorage reinforcing bar 30 in the vicinity of this end face, it is necessary to simplify the shapes and arrangements of the female metal fitting 31 and the anchoring reinforcing bar 30. If the shape is complicated or the number of anchorage bars 30 used is large, the female metal fittings 31 or the anchorage bars 30 tend to divide the lumps of concrete to lower the anchoring strength of the concrete, making the female metal fittings 31 larger than necessary. In addition, there is a problem that the anchoring rebar 30 must be buried deep in the concrete member.

Since the outer shape of the male fitting 33 provided with the wedge portion 34 is press-fitted into the slit 32 provided in the female fitting 31, it is necessary to manufacture and manage it so that there is no dent or deformation. The same can be said for the slit 32,
It must be manufactured with high dimensional accuracy in a shape that fits on the wedge surface. If the male fitting 33 is press-fitted unless it is fitted well to the wedge surface, the contact area between the slit 32 and the wedge portion 34 is reduced, and the joining mechanism including the male fitting 33 and the female fitting 31 embedded in the concrete member is joined. There is a problem of insufficient strength. On the contrary, the wedge part 3
When the size of 4 is larger than the size of the slit 32, the male fitting 33 is insufficiently press-fitted, and similarly, the joining mechanism including the male fitting 33 and the female fitting 31 embedded in the concrete member is joined. It causes a lack of strength.

The present invention simplifies the shape of the metal fittings such as the fixing rebars embedded in the concrete member to improve the fixing strength, and further reduces the shape and dimensional accuracy of the wedge portion 34 and the slit 32. Shape or material,
An object of the present invention is to provide a metal fitting for a concrete member having high bond strength, which can be easily mass-produced.

[0011]

Means for Solving the Problems The inventors of the present invention pursued the basic conditions required for joining metal fittings, and in order to reasonably transfer the load applied to the fixing-side metal fittings to the concrete member, concrete The number of fixing bars used for female metal fittings embedded in members has been reduced, the size of the female metal fitting body has been optimized, and the shape of the fixing metal fittings such as fixing steel bars has been simplified. In addition, the present inventors have focused on manufacturing a joint metal fitting having an improved shape or material at the joint portion where the female metal fitting and the male metal fitting are in contact with each other.

First, the joining metal fitting according to the present invention has a shape in which a wedge-shaped male metal fitting is press-fitted in order to join a female metal fitting buried in a mating end face of a concrete member and a female metal fitting buried in a mating end face of another concrete member. In the joining metal fitting, the tip of the fixing bar of the female metal fitting is arranged on the inner side of the concrete from the root part of the fixing bar, and a fixing flange is further provided. In addition, the root part of the fixing muscle is provided on the center line of the female fitting body.
The center line of the female metal fitting body in the present invention means a cutting surface passing through the center of the female metal fitting body in the depth direction h from the concrete upper surface side to the concrete inside side and a cutting surface passing through the center of the female metal fitting body in the width direction w. A line formed by crossing. The female metal fitting body embedded in the mating end face of the concrete member is provided with a slit having a C-shaped cross section into which the wedge portion of the male metal fitting can be press fitted. Then, a fixing streak is arranged in a direction from the back of the mating surface of the female fitting main body to the inside of the concrete when the female fitting and the female fitting are joined, and a fixing flange is provided at the tip of the fixing streak. The shape of the fixing streak may be a shape that is bent immediately at a position protruding from the back portion of the female metal fitting body, or may be bent between the back portion and the fixing flange. In short, it is important to arrange the fixing flange on the inner side of the concrete rather than the root of the fixing streak. It is preferable to provide the root portion of the anchoring streak on the center line of the back part of the female metal fitting body in order to transfer the load applied to the joining metal fitting from the female metal fitting body to the anchoring muscle without difficulty. Further, if the position of the fixing flange is deeper inside the concrete than at the root of the fixing streak, the cone-like fracture strength of the concrete can be further increased. Further, the cross-sectional shape for fixing the fixing streaks and the fixing flange is not limited to a circular shape, and may be a polygon such as a quadrangle or an ellipse, and is not limited to a specific shape.

Further, a reinforcing rib is provided on the bent portion of the fixing bar. By providing the reinforcing ribs, the strength of the fixing bar of the bent portion is reinforced, and the integrated female metal fitting is not deformed as a whole and is strong.

Further, the female metal fitting body, the fixing bar, the fixing flange, and the reinforcing rib are integrally formed as an iron casting. By integrally forming the iron-based casting, assembly and welding work is unnecessary, reliability is improved, and mass production can be easily performed.
It is desirable to use a spheroidal graphite cast iron casting.

Next, in order to join the female metal fitting buried in the mating end face of the concrete member and the female metal fitting buried in the mating end face of another concrete member, in the fitting metal fitting of a wedge type, The surface layer portion of the member in which the female metal fitting and the male metal fitting are in contact with each other is a ferrite main base, and the central portion is a pearlite main base. Since the base of the surface layer contacting each other is mainly made of ferrite, the hardness is lower than that of the base made of pearlite, the surface fits well when the wedge-shaped male metal fitting is press-fitted into the female metal fitting, and some surface irregularities are plastically deformed. It is possible to obtain a strong bonding strength. Also,
Since the center part of the material is mainly composed of pearlite, both tensile strength and hardness are high, and the joint strength of the joint metal as a whole can be secured.

Further, a material in which the surface layer portion of either one of the female metal fitting and the male metal fitting in contact with each other is a ferrite main base and the center is a pearlite main base. If the size of the joining metal fitting is relatively small and the depth of the ferrite main base on the surface layer is not so large, if either one of the female metal fittings or the male metal fitting is the ferrite main base, The effect is sufficiently exhibited, and a metal fitting with high joint strength can be obtained. The term "ferrite-based base" in the present invention means a base in which a part of pearlite is mixed in the ferrite base, and a part of pearlite may be mixed in the ferrite base and the base is 100% ferrite. Good. The perlite-based base means a base in which some ferrite is mixed in the pearlite base, and some ferrite may be mixed or 100% pearlite may be contained in the base.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to FIGS. 1 to 5, but the present invention is not limited to these.

[0018]

Embodiment 1 FIGS. 1 and 2 show a first embodiment of the present invention. FIG. 1 is a perspective view before joining showing the structure of the entire joining fitting,
FIG. 2 is a partial cross-sectional view of the female metal fitting embedded in the concrete member. At the mating end face 13 of the concrete member 12,
Moreover, the female metal fitting 2 was embedded in the position of the concrete upper surface side 14. The female metal fitting 2a was also embedded in the mating end surface 13a of the other concrete member 12a. The female fittings 2 and 2a are the same fitting. The joining metal fitting 1 for joining is composed of two female metal fittings 2 and 2a and a wedge-shaped male fitting 3. Back part 1 of mating end face 13 of female fitting body 4 of female fitting 2
5, the fixing bar 6 is projected from the position on the center line 11 (the position of the root portion 5), and the fixing bar 6 is bent into the concrete inner side 16 by a dimension L from the position on the center line 11 in a substantially S shape. The tip portion 7 of the Further, a fixing flange 8 is provided at the tip portion 7 of the fixing streak 6. Reinforcing ribs 9 are arranged at the positions where the fixing bars 6 are bent.

Since the fixing flange 8 is bent and provided on the inner side 16 of the concrete with respect to the position of the root portion 5 of the fixing streak 6 by a dimension L, the fixing strength due to the cone-like fracture of the concrete is significantly improved. Further, since the reinforcing ribs 9 are provided, the strength of the fixing bar 6 in the bent portion is reinforced, and the integrated female metal fitting 2 is not deformed as a whole and is sturdy.

Furthermore, the female metal fitting body 4 into which the male metal fitting 3 is press-fitted
Has a C-shaped cross section, and the blade portion 10 is provided on the surface to be joined to the male fitting 3. Since the blade part 10 has a saw blade shape, the male fitting 3
The tip of the blade portion was plastically deformed at the final stage of press-fitting, and the male fitting 3 was brought into close contact with and firmly joined.

Further, the male fitting 3 has an H-shaped basic cross section, and an inner surface 17 contacting the female fittings 2 and 2a is provided with a slope for producing a wedge effect. Further, the outer surface 19 where the H-shaped ribs 18 intersect is made thicker than the end surface 20 side. Since the wall thickness is increased, even if a force such that a load is applied to the end face 20 and a bending moment acts, the entire male fitting is not deformed and is sturdy.

Female fittings 2 and 2a provided with a saw-toothed blade portion 10
Since the material of requires plastic deformation, for example, JIS / FCD
The spheroidal graphite cast iron with a lower hardness such as 450 is made, and the male fitting 3 is made from the spheroidal graphite cast iron with a higher hardness such as JIS / FCD700. Good, strong, and easy to mass-produce.

[0023]

Second Embodiment FIGS. 3 to 5 show a second embodiment of the present invention. FIG. 3 is a perspective view showing the entire structure of the joint fitting before joining,
FIG. 4 is a partially enlarged cross-sectional view showing a state where the male metal fitting 3 is press-fitted into the female metal fittings 2 and 2a. FIG. 5 is a metallographic photograph of a cross section of the male fitting 3 from the surface layer portion 21 toward the central portion 22.

The female metal fittings 2 and 2a constituting the joining metal fitting 1 have the same basic shape as that of the first embodiment, but the male metal fitting 3 is used.
Only the surface 23 of the female metal fitting 2 that comes into contact with
It was a smooth surface with only a gradient. The material was spheroidal graphite cast iron and was manufactured by using JIS / FCD600 or the like with a higher hardness.

The male fitting 3 has the same shape as that of the first embodiment, and is made of spheroidal graphite cast iron, which is a material having a higher hardness such as JIS / FCD600. Due to the high hardness, the entire metallographic structure was a pearlite-based matrix. After that, heat treatment was performed to generate a ferrite-based matrix only in the surface layer portion. This ferrite main base is JIS / FCD4
The hardness is as low as that of spheroidal graphite cast iron such as 00, female metal fittings 2, 2a
When the male metal fitting 3 was press-fitted into the, the joint surface was well-fitted, and even if there were slight irregularities on the joint surface of the male metal fitting 3, it was soft and plastically deformed, and there was no problem in the press-fitting work. Further, since the center part is a base mainly composed of pearlite, there is no problem in strength and high bonding strength is obtained.

5 (a) and 5 (b) are micrographs showing a metallographic structure at a magnification of 75 in which the cross section from the surface layer portion 21 to the central portion 22 of the male fitting 3 shown in FIG. Is. FIG. 5A is a structural photograph showing the surface layer 17 side. FIG. 5 (b) shows a structure photograph continuous from the structure photograph of FIG. 5 (a). From the surface to a depth of about 0.7 mm, the ferrite conversion rate was 82%, which was a ferrite-based base. Next, from the surface to the vicinity of 2 mm, there is a mixed base of ferrite and pearlite, and it is recognized that the base mainly of ferrite is gradually changed to the base of pearlite. After that, it was a completely pearlite-based base with a pearlite conversion rate of 68% until the central part 22. The depth of the ferrite-based matrix of the surface layer portion 21 can be adjusted by changing the heat treatment conditions.
It is not limited to mm. Similarly, it is not limited that the base where ferrite and perlite are mixed is within 2 mm from the surface. Furthermore, the ferrite conversion rate of the surface layer is 82% and the pearlite conversion rate of the center is 68%.
There is no limitation on the value of.

[0027]

EFFECTS OF THE INVENTION The joining metal fitting of the present invention reduces the number of fixing bars used in female fittings embedded in a concrete member, has an optimum size of the female fitting main body, and further simplifies the shape of the fixing metal fittings such as fixing reinforcing bars. It is possible to improve the fixing strength of the female metal fitting, further improve the material of the wedge portion, and relax the dimensional accuracy. Further, since the female metal fitting is made of a casting having an integral structure, the welding work for manufacturing the joining metal fitting is unnecessary, and the mass production can be easily performed.

[Brief description of the drawings]

FIG. 1 is a perspective view before joining showing a configuration of an entire joining fitting in a first embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of a female metal member embedded in a concrete member according to the first embodiment of the present invention.

FIG. 3 is a perspective view before joining showing the configuration of the entire joining fitting in the second embodiment of the present invention.

FIG. 4 is a partially enlarged cross-sectional view showing a state in which a male fitting is press-fitted into a female fitting according to the second embodiment of the present invention.

FIG. 5 is a photograph of a metal structure of a cross section of the male fitting in the second embodiment of the present invention.

FIG. 6 is a perspective view showing the structure of the entire conventional joining fitting before joining.

[Explanation of symbols]

1: Joining fitting 2, 2a: Female fitting 3: Male fitting 4: Female fitting main body 5: Root part 6: Fixing muscle 7: Tip part 8: Fixing flange 9: Reinforcing rib 10: Blade part 11: Center line 12, 12a : Concrete member 13, 13a: End surface 14: Concrete upper surface side 15: Back part 16: Concrete inner side 17: Inner surface 18: Rib 19: Outer surface 20: End surface 21: Surface layer 22: Center part 23: Surface

Claims (6)

[Claims] 1. A connecting metal fitting having a shape in which a wedge-shaped male metal fitting is press-fitted to join a female metal fitting buried in a mating end surface of a concrete member and a female metal fitting buried in a mating end surface of another concrete member. A joint fitting for concrete, characterized in that the tip of the fixing bar of the metal fitting is arranged on the inner side of the concrete with respect to the root of the fixing bar, and a fixing flange is further provided. 2. The joining fitting for concrete according to claim 1, wherein the root portion of the anchoring streak is located on the center line of the female fitting main body. 3. The concrete according to claim 1 or 2, wherein the fixing bar is arranged by bending between the female metal fitting body and the tip of the fixing bar, and a reinforcing rib is arranged at the bending part. For metal fittings. 4. The concrete joint fitting according to claim 1, wherein the female fitting main body is a ferrous casting integrally formed with a fixing bar, a fixing flange, and a reinforcing rib. 5. A connecting fitting having a shape in which a wedge-shaped male fitting is press-fitted to join a female fitting buried in a mating end surface of a concrete member and a female fitting buried in a mating end surface of another concrete member. A joining metal fitting for concrete, characterized in that the surface layer portion of the member in which the metal fitting and the male metal fitting are in contact with each other is a ferrite main base, and the center is a perlite main base. 6. The method according to claim 1, wherein a surface layer portion of either one of the female metal fitting and the male metal fitting in contact with each other is composed of a ferrite main base, and a central portion is composed of a pearlite main base. Metal fittings for concrete.