JP2023123114A - Joint structure and joint installation method - Google Patents

Abstract

The present invention provides a joint structure and a joint construction method that make it possible to easily construct a joint between shaped steels embedded in concrete.
A joint structure (1) is a joint structure that connects lower main steel members (11, 11) buried in concrete (17), and both of the lower main steel members (11, 11) that are connected to each other in the longitudinal direction. The joint reinforcing bar portion is arranged in the vicinity of the connection portion 11P between the lower main steel members 11, 11 so as to extend in the longitudinal direction over the entire length of the joint, and is embedded in the concrete 17 together with the lower main steel members 11, 11. 21.
[Selection drawing] Fig. 1

Description

The present invention relates to a joint structure and a joint construction method.

Conventionally, there is known a composite member including, for example, an embedded mold made of concrete and a main steel material made of shaped steel fixed to the embedded mold (see, for example, Patent Document 1 below). In this composite member, a steel-framed concrete structure is constructed by placing concrete in an embedded form so as to embed the main steel material. Since this type of composite member has high rigidity itself, it is possible to omit shoring on the bottom surface and side surfaces of the formwork, which is effective in improving the productivity of frame construction.

Japanese Patent Application Laid-Open No. 2021-183799

When this type of composite member is divided and installed, joints of the main steel material are generated between the members, and the joint of the main steel material may be a friction-welded joint or a welded joint. However, with these joint structures, the fact that there is a lot of work to be done on site and the need to install precise main steel materials can be factors that impair workability. In view of such problems, an object of the present invention is to provide a joint structure and a joint construction method that make it possible to easily construct a joint between shaped steels buried in concrete.

The joint structure of the present invention is a joint structure for connecting shaped steels embedded in concrete, and is shaped so as to extend in the longitudinal direction across both ends of the shaped steels that are longitudinally connected to each other. It is provided with a joint rebar part that is placed in the vicinity of the joint between the steels and that is embedded in the concrete together with the shape steel.

In the joint structure of the present invention, a plurality of joint reinforcing bar portions may be provided in parallel with respect to one connecting portion, and the joint reinforcing bar portions may be connected to each other via other reinforcing bars. . Affixing portions may be provided at both ends of the joint reinforcing bar portion for enhancing the fusing performance to concrete. The joint reinforcing bar portion may form part of the hoop reinforcing bar.

The shaped steel is the main steel material fixed to the precast concrete slab along the surface of the precast concrete slab in a composite half precast member having a precast concrete slab, and the concrete is cast using the precast concrete slab as an embedded formwork. It may be done.

In the joint structure of the present invention, a plurality of joints between the main steel members are present along the surface of the precast concrete slab so as to be aligned in a direction orthogonal to the longitudinal direction, and a plurality of joints are arranged with respect to the plurality of joints. joint reinforcing bar portions may be connected to each other at a position farther from the precast concrete slab than the main steel material.

The composite half-precast member further includes a second main steel member located parallel to the main steel member at a position further from the precast concrete slab than the main steel member, the ends of the second main steel member being longitudinally connected to each other. a second joint reinforcing bar portion that is arranged in the vicinity of the connecting portion of the second main steel members so as to extend longitudinally across both of the portions and is embedded in the concrete together with the second main steel members; and a connecting reinforcing bar portion that connects the reinforcing bar portion for the second joint and the reinforcing bar portion for the second joint.

A plurality of steel units each including a main steel material and a second main steel material are arranged in a direction orthogonal to the longitudinal direction, and have a joint reinforcing bar section, a second joint reinforcing bar section, and a connecting reinforcing bar section, A plurality of small reinforcing bar units arranged corresponding to each joint of each steel material unit, and a plurality of small reinforcing bar units extending in a direction intersecting the longitudinal direction at a position farther from the precast concrete slab than the second main steel material. A second connecting reinforcing bar portion for connecting the units may be further provided.

The joint construction method of the present invention is a joint construction method for constructing a joint structure that connects shaped steels embedded in concrete, and includes both ends of the shaped steels that are connected to each other in the longitudinal direction. A joint reinforcing bar is arranged in the vicinity of the joint between the shaped steels so as to extend in the longitudinal direction, and concrete is placed so as to bury the joint reinforcing bar and the shaped steel together.

Advantageous Effects of Invention According to the present invention, it is possible to provide a joint structure and a joint construction method that make it possible to easily construct a joint between shaped steels buried in concrete.

(a) is an exploded perspective view showing an exploded composite half precast member and a reinforcing bar cage in the joint structure of the first embodiment, and (b) is a side view showing them as viewed in the Y direction. be. FIG. 8A is a side view of the second embodiment, and FIG. 8B is a side view of the composite half precast member and the reinforcing bar cage in the joint structure of the third embodiment, viewed in the Y direction; (a) is a perspective view showing a composite half precast member and a reinforcing bar cage in the joint structure of the fourth embodiment, and (b) is a side view showing them as viewed in the Y direction. (a) is a perspective view showing a composite half precast member and a reinforcing bar cage in the joint structure of the fifth embodiment, and (b) is a side view showing them as viewed in the Y direction. (a) is a perspective view showing a composite half precast member and a reinforcing bar cage in the joint structure of the sixth embodiment, and (b) is a side view showing them as viewed in the Y direction. (a) is a perspective view showing a composite half precast member and a reinforcing bar cage in the joint structure of the seventh embodiment, and (b) is a side view showing them as viewed in the Y direction. (a) is a perspective view showing a composite half precast member and a reinforcing bar cage in the joint structure of the eighth embodiment, and (b) is a side view showing them as viewed in the Y direction. (a) is a perspective view showing a composite half precast member and a reinforcing bar cage in the joint structure of the ninth embodiment, and (b) is a side view showing them as viewed in the Y direction. It is a side view which shows the compound half precast member and reinforcing bar cage|basket in the joint structure which concerns on the modification of 9th Embodiment by the line of sight of the Y direction.

Hereinafter, each embodiment of a joint structure and a joint construction method according to the present invention will be described in detail with reference to the drawings. In the following description, the same reference numerals are given to the same or equivalent components, and overlapping descriptions are omitted.

(First embodiment)
The joint structure 1 and the joint construction method of the present embodiment are applied to the connecting portion between the composite half precast members 3 shown in FIG. In the following, an XYZ orthogonal coordinate system is set as shown in the drawing, and X, Y, and Z may be used to describe the positional relationship of each part. In addition, when using terms such as “upper/lower” and “upper/lower” below, they correspond to the upper and lower sides of the composite half precast member 3 in the posture shown in FIG. vertically downward. In addition, the features of the constituent elements may be exaggerated on the drawings, and the dimensional ratios of the constituent elements on the drawings do not necessarily match the real thing, nor do they necessarily match between the drawings.

The composite half precast member 3 includes a rectangular precast concrete slab 5 functioning as an embedded formwork, and a steel material unit 7 fixed to the precast concrete slab 5 . The precast concrete slab 5 has a flat plate shape with a thickness in the Z direction, and has a rectangular shape in plan view with short sides extending in the X direction and long sides extending in the Y direction. The steel material unit 7 is provided so as to stand vertically upward from the surface 5a of the precast concrete slab 5, and includes two main steel materials 11 and 12 and a connection material 15 that connects the main steel materials 11 and 12. ing. When distinguishing between the main steel materials, one is called the lower main steel material 11 (main steel material) and the other is called the upper main steel material 12 (second main steel material). The composite half precast member 3 has two steel material units 7 arranged in the X direction. The steel unit 7 may be appropriately joined to the precast concrete slab 5 by a known joining structure.

The lower main steel material 11 extends straight in the Y direction along the surface 5a of the precast concrete slab 5. As shown in FIG. The upper main steel member 12 extends straight in parallel with the lower main steel member 11 at a position farther from the precast concrete slab 5 in the Z direction than the lower main steel member 11 . The lower main steel material 11 and the upper main steel material 12 are formed of shaped steel extending straight in the Y direction. In the example shown in the figure, the shaped steels used as the main steels 11 and 12 are flat steels, but the main steels 11 and 12 are not limited to flat steels and may be angle steels, H steels, C-shaped steels, L-shaped steels, CT-shaped steels, and the like. may be configured. The lower main steel material 11 and the upper main steel material 12 extend over the entire length of the precast concrete slab 5 in the Y direction. The connecting members 15 include shear reinforcing bars that connect the lower main steel member 11 and the upper main steel member 12 in the Z direction, diagonal members that connect diagonally, and the like, but most of them are omitted to avoid complication of the drawing. and only part of it is shown. A steel material unit 7 is configured by connecting a lower main steel material 11, an upper main steel material 12, and a connecting material 15 to each other by welding or the like and integrating them.

Composite half precast members 3 as described above are connected to each other in the X direction and the Y direction, and concrete 17 (see FIG. 1B) is placed on the surface 5a side of the precast concrete slab 5, so that the inside A steel frame concrete structure in which the steel unit 7 is embedded is constructed. Since the composite half-precast member 3 itself has high rigidity, it is possible to omit support for the bottom surface and side surfaces of the formwork in this construction of the structure. In the construction of the structure as described above, water stopping treatment is applied between adjacent precast concrete slabs 5, 5 for placing concrete. On the other hand, at the connecting portion between the adjacent steel units 7, 7, the ends of the lower main steel members 11, 11 are positioned so that their end faces face each other, and the ends of the upper main steel members 12, 12 face each other. are located side by side. The lower main steel members 11, 11 and the upper main steel members 12, 12 must be connected in the longitudinal direction (Y direction) with an appropriate joint structure that enables stress transmission.

A joint structure 1 between the lower main steel members 11 and 11 and between the upper main steel members 12 and 12 and a joint construction method for constructing the joint structure 1 will be described below. In the following description, the connecting portion between the composite half-precast members 3, 3 adjacent in the Y direction will be referred to as the "connecting portion 3P", and the connecting portion between the precast concrete slabs 5, 5 in the connecting portion 3P will be referred to as the "connecting portion 5P”. A connecting portion between the steel units 7 adjacent in the Y direction is called a "connecting portion 7P", and a connecting portion between the lower main steel members 11, 11 in the connecting portion 7P is called a "connecting portion 11P". , the connecting portion between the upper main steel members 12, 12 of the connecting portion 7P is referred to as a "connecting portion 12P".

A reinforcing bar cage 20 shown in FIGS. 1A and 1B is used to construct the joint structure 1 . FIG. 1(a) is an exploded perspective view showing the composite half precast members 3, 3 and the reinforcing bar cage 20 in the joint structure 1 of the present embodiment, and (b) shows the joint structure 1 in the Y direction. FIG. 10 is a side view as seen from the line of sight; In FIG. 1(a), in order to avoid complication of the drawing, only one set of the composite half precast members 3, 3 adjacent in the Y direction is shown, and only one unit of the reinforcing bar cage 20 corresponding to this set is shown. It is shown. In reality, a large number of sets of these composite half-precast members 3, 3 and units of reinforcing bar cages 20 are continuously repeated in the X direction.

The reinforcing bar cage 20 includes a joint reinforcing bar portion 21 and a joint reinforcing bar portion 22 arranged in parallel. The joint reinforcing bar portion 21 extends in the Y direction and is arranged in a range in the Y direction so as to cover both ends of the connected lower main steel members 11, 11, and is arranged in the vicinity of the connecting portion 11P. It is a thing. In the Y direction, the center of the joint reinforcing bar portion 21 may be positioned at the position of the connecting portion 11P. The joint reinforcing bar portion 21 is located in the immediate vicinity of the lower main steel materials 11, 11 while being displaced in the X direction, and may be in contact with the lower main steel materials 11, 11. , 11 may be slightly spaced in the X direction. Similarly, the joint reinforcing bar portion 22 (second joint reinforcing bar portion) extends in the Y direction and is arranged in a range in the Y direction so as to cover both ends of the upper main steel members 12, 12 to be connected. , are arranged in the vicinity of the connecting portion 12P. In the Y direction, the center of the joint reinforcing bar portion 22 may be positioned at the position of the connecting portion 12P. The joint reinforcing bar portion 22 is positioned in close proximity to the upper main steel members 12, 12 while being displaced in the X direction, and may be in contact with the upper main steel members 12, 12. A slight gap may be provided between them in the X direction.

The joint reinforcing bar portions 21 and 22 are made of reinforcing bars extending in the Y direction, and fixing portions 21a and 22a are provided at both ends thereof for improving the fixing performance to the concrete 17 . In the illustrated example, the fixing portions 21a and 22a are semicircular hook portions formed by bending both end portions of the joint reinforcing bar portions 21 and 22 into a semicircular hook shape. Also, in the illustrated example, the semicircular hook portion is curved in a plane perpendicular to the X direction, but it may be curved in a plane parallel to the surface 5a of the precast concrete slab 5. FIG. Also, the semicircular hook portion in the example of the drawing may be turned upside down. Further, the anchoring portions 21a and 22a are not limited to such semicircular hook portions, and may be mechanical anchoring portions provided at both ends of the straight joint reinforcing bar portions 21 and 22, for example.

The reinforcing bar cage 20 further includes a connecting reinforcing bar portion 23 and a second connecting reinforcing bar portion 25 . The connecting reinforcing bar portion 23 extends linearly in the Z direction and connects the joint reinforcing bar portion 21 and the joint reinforcing bar portion 22 . Moreover, the connecting reinforcing bar portion 23 may function as a shear reinforcing bar in the finally completed steel-framed concrete structure. In addition, the second connecting reinforcing bar portion 25 may function as a distributing bar in the finally completed steel-framed concrete structure. In the illustrated example, the joint reinforcing bar portion 21 and the joint reinforcing bar portion 22 are connected by two connecting reinforcing bar portions 23, 23 arranged in parallel with their positions shifted in the Y direction. A unit composed of the joint reinforcing bar portion 21, the joint reinforcing bar portion 22, and the two connecting reinforcing bar portions 23, 23 that are connected and integrated as described above is called a "small reinforcing bar unit 27." , in the joint structure 1, one reinforcing-bar small unit 27 is arranged near each connecting portion 7P. The plurality of small reinforcing-bar units 27 arranged in the X direction are continuously connected to each other by the second connecting reinforcing-bar portions 25 , 25 .

The second connecting reinforcing bar portion 25 is arranged at a position farther from the precast concrete slab 5 than the upper main steel member 12 and extends linearly in the X direction. In the illustrated example, the reinforcing bar cage 20 includes two second connecting reinforcing bar portions 25, 25 arranged in parallel with their positions shifted in the Y direction. The plurality of small reinforcing bar units 27 are connected to each other by the two second connecting reinforcing bar portions 25 , 25 . Moreover, each of the second connecting reinforcing bar portions 25, 25 passes in the immediate vicinity of each intersection position between the joint reinforcing bar portion 22 and the connecting reinforcing bar portions 23, 23, respectively. The reinforcing bar cage 20 is formed by connecting the above-described joint reinforcing bar portions 21 and 22, connecting reinforcing bar portions 23 and 23, and second connecting reinforcing bar portions 25 and 25 to each other with wire or the like.

In addition, in the above-described configuration of the reinforcing bar cage 20, the plurality of joint reinforcing bar portions 21 arranged with respect to the plurality of connecting portions 11P are connected to each other by the connecting reinforcing bar portions 23, 23 and the second connecting reinforcing bar portions 25, 25. It can be said that they are connected to each other at a position farther from the precast concrete slab 5 than the lower main steel material 11 via. That is, if the joint reinforcing bar portion 22 is omitted from the steel material unit 7, the joint reinforcing bar portion 22 of the reinforcing bar cage 20 may be omitted.

Next, a joint construction method for constructing the joint structure 1 using the reinforcing bar cage 20 as described above will be described with reference to FIG. 1 . In this construction method, first, a plurality of composite half-precast members 3 are arranged corresponding to the positions of the steel-framed concrete structure to be constructed. At this time, the precast concrete slabs 5 of each composite half precast member 3 are two-dimensionally arranged in the XY directions, and water stopping treatment is applied between the precast concrete slabs 5 adjacent in the X and Y directions. In the composite half-precast members 3, 3 adjacent to each other in the Y direction, as described above, the ends of the lower main steel materials 11, 11 are positioned so that the end faces abut each other at the connecting portion 7P between the steel material units 7, 7. Then, the ends of the upper main steel materials 12, 12 are positioned so that the end surfaces thereof are butted against each other. Although only two connecting portions 7P are shown in FIG. 1(a), in reality, a large number of connecting portions 7P are repeatedly present continuously in the X direction.

On the other hand, the above-mentioned reinforcing bar cage 20 is prepared using reinforcing bars, cords, and the like. As described above, in FIG. 1A, only two small reinforcing bar units 27 of the reinforcing bar cage 20 are shown corresponding to the two connecting portions 7P. A large number of units 27 are continuously present in the X direction. Then, the reinforcing bar cage 20 is placed on the surface 5a of the precast concrete slab 5 in the positional relationship shown in FIG. is installed.

Next, the precast concrete slab 5 of the composite half precast member 3 is used as an embedded formwork, and a necessary formwork (not shown) is installed, and concrete 17 is poured into these formwork. The concrete 17 is cast on the surface 5a of the precast concrete slab 5 to a height where the steel unit 7 and the reinforcing bar cage 20 are all buried, and finally the steel unit 7 and the reinforcing bar cage 20 are together in the hardened concrete 17. Buried.

As a result, a steel-framed concrete structure in which the steel unit 7 is embedded is constructed, and the joint structure 1 is completed. The joint structure 1 includes a joint reinforcing bar portion 21 embedded in the concrete 17 together with the lower main steel members 11, 11, a joint reinforcing bar portion 22 embedded in the concrete 17 together with the upper main steel members 12, 12, It has

In such a joint structure 1, the joint reinforcing bar portion 21 extends in the Y direction so as to overlap both the ends of the lower main steel members 11, 11, and the lower main steel members 11 extend in the vicinity of the connecting portion 11P. , 11 together with the concrete 17, a joint capable of transmitting stress between the lower main steel members 11, 11 is constructed via the joint reinforcing bar portion 21 and the concrete 17. As shown in FIG. Similarly, the joint reinforcing bar portion 22 extends in the Y direction so as to wrap over both ends of the upper main steel members 12, 12, and joins the upper main steel members 12, 12 in the vicinity of the connection portion 12P to form the concrete 17. Since they are buried, a joint is constructed that allows stress transmission between the upper main steel members 12 , 12 via the joint reinforcement 22 and the concrete 17 . Here, the reinforcing bar thickness and thickness of the joint reinforcing bar portions 21, 22 are set so as to enable the necessary stress transmission between the lower main steel members 11, 11 and the necessary stress transmission between the upper main steel members 12, 12. The length in the Y direction, the positional relationship with the connecting portions 11P and 12P, the specifications of the fixing portions 21a and 22a, etc. may be appropriately designed.

The effects of the joint structure 1 as described above will be described. If a friction welded joint or a welded joint were adopted as the joints between the lower main steel members 11, 11 and between the upper main steel members 12, 12, there would be a lot of work to be done on site, and it would be difficult to precisely install the main steel members. It can be a factor that impairs workability. Moreover, when the distance between the steel material units 7 in the X direction is narrow, it is difficult to work inside the composite half precast member 3, and it may not be possible to construct a friction joint or a weld joint. A lap joint structure is also conceivable in which the ends of the steel materials themselves of the lower main steel material 11 and the upper main steel material 12 are lapped to transmit stress. In this case, the lower main steel material 11 and the upper main steel material 12 are precast. Since it is necessary to protrude from the concrete slab 5 in the Y direction, there is a possibility that workability during installation of the composite half precast member 3 will be reduced. A joint structure using a joint steel material is also conceivable, but there is a high possibility that the concrete 17 will be insufficiently filled into the joint portion, and the cost required for the joint portion will also increase. On the other hand, when constructing the joint structure 1, it is sufficient to install the joint reinforcing bars 21 and 22 along the vicinity of the connecting portion 11P and the connecting portion 12P before placing the concrete 17. The joint structure 1 can be constructed at a low cost, and installation errors can be absorbed within the space between the joint reinforcing bar portions 21 and 22 and the connecting portions 11P and 12P, so workability is also good. In addition, the joint structure 1 may use ordinary deformed reinforcing bars that do not require special processing, which contributes to cost reduction.

A plurality of joint reinforcing bar portions 21 and 22 arranged in the X direction are integrated as a reinforcing bar cage 20 via connecting reinforcing bar portions 23 and second connecting reinforcing bar portions 25 . Therefore, by simply installing the reinforcing bar cage 20 along the connecting portion 3P between the composite half precast members 3, the plurality of joint reinforcing bar portions 21 and 22 can be collectively arranged along the connecting portions 11P and 12P. can. Therefore, on-site work is reduced and workability is good. In particular, since the steel material unit 7 includes two stages of the main steel material, the lower main steel material 11 and the upper main steel material 12, it is difficult to arrange the joint reinforcing bar part 22 of the connection part 12P positioned away from the precast concrete slab 5. However, according to the joint structure 1, by installing the reinforcing bar cage 20, the joint reinforcing bar portion 22 can be installed in the vicinity of the connecting portion 12P relatively easily.

(Second embodiment)
The distance between the joint reinforcing bar portions 21 and 22 and the main steel members 11 and 12 may be changed according to the required structural performance of the joint, the joint length, the required amount of reinforcing bars, and the like. For example, in the joint structure 201 of the present embodiment shown in FIG. 2(a), each reinforcing-bar small unit 27 is shifted in the X direction compared to the joint structure 1 (FIG. 1). In the X direction, the joint reinforcing bar portion 21 is positioned substantially at the center between the adjacent connecting portions 11P, 11P, and the joint reinforcing bar portion 22 is positioned at substantially the center position between the adjacent connecting portions 12P, 12P. are doing. 2 and subsequent drawings, the illustration of the concrete 17 (FIG. 1(b)) in which the main steel members 11 and 12 and the joint reinforcing bars 21 and 22 are embedded is omitted in order to avoid complication of the drawings.

(Third Embodiment)
Further, the numbers of the joint reinforcing bar portions 21 and 22, the connecting reinforcing bar portion 23, and the second connecting reinforcing bar portion 25 in the reinforcing bar cage 20 may be changed as appropriate. For example, in the joint structure 301 of the present embodiment shown in FIG. 2(b), two small reinforcing-bar units 27 are arranged in close proximity to one connecting portion 7P so as to sandwich the connecting portion 7P in the X direction. there is Then, two joint reinforcing bar portions 21 are arranged in the immediate vicinity of one connecting portion 11P so as to sandwich the connecting portion 11P in the X direction. Two joint reinforcing bar portions 22 are arranged in the immediate vicinity so as to sandwich them.

(Fourth embodiment)
Further, a plurality of joint reinforcing bar portions 21 may exist in parallel with respect to one connecting portion 11P, and a plurality of joint reinforcing bar portions 22 may exist in parallel with one connecting portion 12P. As a result, even when relatively thin reinforcing bars are used, the amount of steel required for the joint can be easily secured, and the length of the joint reinforcing bar portions 21 and 22 in the Y direction can be suppressed. Further, the joint reinforcing bar portions 21 and 22 may be arranged in an appropriate direction depending on the distance between the joint reinforcing bar portions 21 and 22 and the relationship with the cover. This makes it possible to suppress the occurrence of bond splitting cracks and improve the stress transmission performance of the joint structure. For example, in the joint structure 401 of this embodiment shown in FIGS. 3A and 3B, a reinforcing bar cage 420 is used instead of the reinforcing bar cage 20 of the first embodiment. In the reinforcing bar cage 420, a plurality of joint reinforcing bar portions 21 (three in the example shown in the figure) are arranged in parallel in the Z direction near the connecting portion 11P. Similarly, a plurality of (three in the illustrated example) joint reinforcing bar portions 22 are arranged in parallel in the vicinity of the connecting portion 12P in the Z direction. Further, while the fixing portions 21a and 22a of the joint reinforcing bar portions 21 and 22 in the first embodiment (FIG. 1) are curved in a plane perpendicular to the X direction, the joint reinforcing bar portion 21 in FIG. , 22 are curved in a plane parallel to the surface 5 a of the precast concrete slab 5 . The plurality of joint reinforcing bar portions 21 and the plurality of joint reinforcing bar portions 22 are connected to each other via two connecting reinforcing bar portions 23 , 23 .

(Fifth embodiment)
When a plurality of joint reinforcing bar portions 21 and 22 are installed for one connecting portion 11P and 12P, in order to avoid interference between the joint reinforcing bars and to disperse damage within the joint, the Y-direction length and Joint reinforcing bar portions 21 and 22 having fixing portions 21a and 21b facing in different directions may be mixed. For example, in the joint structure 501 of this embodiment shown in FIGS. 4A and 4B, a reinforcing bar cage 520 is used instead of the reinforcing bar cage 20 of the first embodiment. In the reinforcing bar cage 520, two joint reinforcing bar portions 21 (joint reinforcing bar portions 21s and 21t) are arranged near the connecting portion 11P, and two joint reinforcing bar portions 22 (jointing reinforcing bar portions) are arranged near the connecting portion 12P. 22s, 22t) are arranged. The joint reinforcing bar portions 21t and 22t extend longer in the Y direction than the joint reinforcing bar portions 21s and 22s. Further, the fixing portions 21a and 22a of the joint reinforcing bar portions 21s and 22s are semicircular hook portions that curve in a plane perpendicular to the X direction, and the fixing portions 21a and 22a of the joint reinforcing bar portions 21t and 22t are precast. It is a semicircular hook portion that curves in a plane parallel to the surface 5 a of the concrete slab 5 . In this manner, since the joint reinforcing bar portions 21s and the joint reinforcing bar portions 21t have different lengths and different orientations of the fixing portions 21a and 22a, interference between the joint reinforcing bar portions 21s and 21t can be avoided. Similarly, interference between the joint reinforcing bar portion 22s and the joint reinforcing bar portion 22t can also be avoided.

In addition, in the reinforcing bar cage 520 , one reinforcing bar small unit 27 includes four connecting reinforcing bar portions 23 . Of these, two connecting reinforcing bar portions 23s, 23s are arranged at the positions of both ends in the Y direction of the joint reinforcing bar portions 21s, 22s. These connecting reinforcing bar portions 23s, 23s connect the joint reinforcing bar portions 21s, 22s to each other, and connect the joint reinforcing bar portions 21t, 22t to each other. The remaining two connecting reinforcing bar portions 23t, 23t are arranged at the positions of both ends of the joint reinforcing bar portions 21t, 22t in the Y direction. 22t are connected to each other.

(Sixth embodiment)
The joint reinforcing bar portions 21 and 22 may be part of the hoop bar. For example, in the joint structure 601 of this embodiment shown in FIGS. 5(a) and 5(b), a reinforcing bar cage 620 is used instead of the reinforcing bar cage 20 of the first embodiment. In the reinforcing bar cage 620 , the small reinforcing bar unit 27 is composed of one hoop bar 31 . The hoop bar 31 is formed by bending a reinforcing bar and joining both ends to form a ring shape, and has a rectangular hoop shape having two sides extending in the Y direction and two sides extending in the Z direction. . One side of the hoop bar 31 extending in the Y direction is arranged near the connecting portion 11P to form the joint reinforcing bar portion 21, and the other side extending in the Y direction is arranged near the connecting portion 12P. and constitutes the joint reinforcing bar portion 22 . Two sides 23j, 23j of the hoop bar 31 extending in the Z direction connect the joint reinforcing bar portions 21, 22 instead of the connecting reinforcing bar portion 23 (see FIG. 1). Moreover, the two sides 23 j and 23 j are provided at both ends of the joint reinforcing bar portions 21 and 22 and function as fixing portions that enhance the fixing performance of the joint reinforcing bar portions 21 and 22 to the concrete 17 . Such hoop bars 31 are provided one by one corresponding to each connecting portion 7P and are arranged in the X direction, and the plurality of hoop bars 31 are connected to each other via the second connecting reinforcing bar portions 25, 25. ing. In this way, the joint reinforcing bar portions 21 and 22 are configured as part of the hoop bars, thereby saving labor in assembling the reinforcing bar cage.

(Seventh embodiment)
Moreover, the hoop reinforcement including the joint reinforcing-bar portions 21 and 22 may extend in a plane parallel to the precast concrete slab 5 . For example, in a joint structure 701 of this embodiment shown in FIGS. 6A and 6B, a reinforcing bar cage 720 is used instead of the reinforcing bar cage 20 of the first embodiment. The reinforcing bar cage 720 has two types of hoop bars 33 and 35 arranged in parallel, and the hoop bars 33 and 35 have two sides extending in the Y direction and two sides extending in the X direction. It has a rectangular hoop shape. The hoop muscles 33 and 35 are sandwiched in the X direction between the adjacent connecting portion 7P and another connecting portion 7P. One hoop muscle 33 is sandwiched between the connecting portions 11P and 11P in the X direction, and the other hoop muscle 35 is sandwiched between the connecting portions 12P and 12P in the X direction.

One side of the hoop reinforcement 33 extending in the Y direction is arranged in the vicinity of one connecting portion 11</b>P that sandwiches the hoop reinforcement 33 to form the joint reinforcement portion 21 . Another side of the hoop 33 extending in the Y direction is arranged in the vicinity of the other connecting portion 11</b>P that sandwiches the hoop 33 to form the joint reinforcement portion 21 . Similarly, one side of the hoop bar 35 extending in the Y direction is arranged in the vicinity of one connecting portion 12P that sandwiches the hoop bar 35 to form the joint reinforcing bar portion 22 . Another side of the hoop bar 35 extending in the Y direction is arranged in the vicinity of the other connecting portion 12P sandwiching the hoop bar 35 to form the joint reinforcing bar portion 22 .

The hoop bars 33 and 35 are connected to each other by four connecting reinforcing bar portions 23 extending in the Z direction, and each connecting reinforcing bar portion 23 connects the joint reinforcing bar portion 21 and the joint reinforcing bar portion 22. there is Two sides 71j and 71j of the hoop bars 33 and 35 extending in the X direction are provided at both ends of the joint reinforcing bar portions 21 and 22 in the Y direction so as to connect the joint reinforcing bar portions 21 and 22 to the concrete 17. It also functions as a fixing section that enhances fixing performance.

(Eighth embodiment)
Moreover, in order to suppress bearing pressure failure of the fixed portions of the joint reinforcing bar portions 21 and 22, a reinforcing steel material may be inserted through the hoop bars as described above. For example, in a joint structure 801 of this embodiment shown in FIGS. 7A and 7B, a reinforcing bar cage 820 is used instead of the reinforcing bar cage 20 of the first embodiment. The reinforcing bar cage 820 has a configuration in which the hoop bars 33 and 35 of the reinforcing bar cage 620 (FIG. 6) are replaced with hoop bars 37 and 39 having slightly different hoop shapes. The hoop muscles 37, 39 have two arcuate joints 73j, 73j curved in a semicircular arc instead of the two sides 71j, 71j (FIG. 6(a)) of the hoop muscles 33, 35 described above. are doing. That is, the two joint reinforcing bar portions 21 of the hoop bar 37 are connected at both ends by the arc connecting portions 73j, 73j, and similarly, the two joint reinforcing bar portions 22 of the hoop bar 39 are also They are connected by arc connecting portions 73j, 73j.

On the other hand, on the surface 5a of the precast concrete slab 5 in the joint structure 801, a circular steel pipe 41 is provided as the reinforcing steel so as to rise in the Z direction near the connecting portion 7P. The steel pipe 41 is joined to the precast concrete slab 5 in a predetermined known structure with the pipe axis directed in the Z direction. The upper end of the steel pipe 41 is positioned slightly higher than the upper main steel material 12 . When the reinforcing bar cage 820 is installed on the precast concrete slab 5, the reinforcing bar cage 820 is guided and positioned by the two steel pipes 41, 41 located in the vicinity of the connecting portion 7P, and the steel pipes 41, 41 are attached to the hoop bars 37. , 39 and placed on the precast concrete slab 5 . Further, the upper end side of the steel pipe 41 protrudes in the Z direction through the area surrounded by the arc connection portion 73j of the hoop bar 39 and the second connection reinforcing bar portion 25 . Moreover, at this time, it is preferable that the arc connecting portions 73j, 73j of the hoop muscles 37, 39 are entirely in contact with each other along the outer peripheral surface of the steel pipe 41. As shown in FIG. That is, it is preferable to set the curvature radii of the circular arc joints 73j, 73j, the position of the steel pipe 41, and the like so as to satisfy such a positional relationship.

Due to the presence of the steel pipe 41 as described above, the resistance to bearing failure of the steel-framed concrete structure can be greatly increased. In particular, if the arc joints 73j, 73j are in tight contact along the outer peripheral surface of the steel pipe 41 as described above, the resistance to bearing pressure failure will be greater. In addition, since the steel pipe 41 is present in the precast concrete slab 5, the steel pipe 41 is used as a guide and the hoop bars 37 and 39 are fitted into the reinforcing bar cage 820. Therefore, the positioning of the reinforcing bar cage 820 is easy.

In addition, it is not essential that the steel pipe 41 is joined to the precast concrete slab 5 in advance, and the steel pipes 41 and 41 may be fixed in advance to the reinforcing bar cage 820 by being fixed to the hoop bars 37 and 39, for example. In this case, the installation work for installing the joint reinforcing bar portions 21 and 22 can be made more efficient, and the positional relationship between the joint reinforcing bar portions 21 and 22 and the main steel members 11 and 12 and the relationship between the joint reinforcing bar portions 21 and 22 can be improved. The arrangement accuracy of each member, such as the positional relationship, is improved. Alternatively, after the reinforcing bar cage 820 is installed on the precast concrete slab 5, the steel pipe 41 may be installed inside the hoop bars 37, 39 along the arc connection portion 73j. Further, even if the reinforcing bars constituting the joint reinforcing bars 21 and 22 are not the hoop bars 37 and 39 but the reinforcing bars having both ends hook-shaped, the steel pipe 41 can be installed inside the hook portions of the reinforcing bars. A similar effect can be expected in Further, as the reinforcing steel material, a reinforcing bar or a square steel pipe may be used instead of the steel pipe 41 .

(Ninth embodiment)
In order to improve the fixing performance of the main steel members 11 and 12 at the joint, a steel member may be added that resists bulging out of the concrete around the main steel members 11 and 12 caused by damage to the joint. By adding such steel materials, the joint length of the main steel materials 11 and 12 can be shortened, and a more rational joint structure can be realized. For example, in a joint structure 901 of this embodiment shown in FIGS. 8A and 8B, a reinforcing bar cage 920 is used instead of the reinforcing bar cage 20 of the first embodiment. The reinforcing bar cage 920 is obtained by adding reinforcing reinforcing bars 45 to the above-described reinforcing bar cage 720 . The reinforcing steel bar 45 is arranged inside the hoop bars 33 and 35 at the central part of the hoop bars 33 and 35 in the Y direction. The reinforcing bar 45 extends in the Y direction as a whole so as to straddle the adjacent joint reinforcing bar section 21 and the joint reinforcing bar section 21 and straddle the adjacent joint reinforcing bar section 22 and the joint reinforcing bar section 22 . It has a U-shape in the plane orthogonal to .

At both ends of the reinforcing bar 45 in the X direction, linear portions 45a extending in the Z direction and contacting the insides of the hoop bars 33 and 35 are present. The ends of the linear portions 45a are connected to each other at a position higher than the upper main steel material 12 via a connecting portion 45b extending in the X direction. The linear portions 45a are connected to the joint reinforcing bar portion 21 and the joint reinforcing bar portion 22, respectively.

According to this joint structure 901 , the rigidity in the direction in which the hoop bars 33 and 35 are crushed in the X direction is improved by the presence of the reinforcing bar 45 . Since the rigidity of the reinforcing reinforcing bars 45 inside the hoop bars 33 and 35 can resist the behavior of the concrete 17 around the lower main steel material 11 and the upper main steel material 12 bulging out, the joint reinforcing bar portion 21 and the joint It is possible to expect an improvement in fixing performance due to the restraint effect on the reinforcing bar portion 22 and the restraint effect.

For example, instead of providing the reinforcing reinforcing bars 45 in the reinforcing bar cage 920, the reinforcing reinforcing bars 45 may be embedded in the precast concrete slab 5 in advance. In this case, when installing the reinforcing bar cage 920 on the precast concrete slab 5, the reinforcing reinforcing bar 45 can be used for alignment. Further, after installing the reinforcing bar cage 920 excluding the reinforcing bar 45 on the precast concrete slab 5, the reinforcing bar 45 may be assembled in place.

Further, as shown in FIG. 9, the reinforcing steel bars 45 are shifted in the X direction so that the reinforcing steel bars 45 straddle the adjacent hoop bars 33 and the adjacent hoop bars 35 and the adjacent hoop bars 35 . 35 may be installed. In this case, one of the linear portions 45a of the reinforcing bar 45 is connected to the joint reinforcing bar portion 21 of the hoop bar 33 and the joint reinforcing bar portion 22 of the hoop bar 35, and the other linear portion 45a of the reinforcing bar 45 is connected to the joint reinforcing bar portion 22 of the hoop bar 35. are connected to the joint reinforcing bar portion 21 of the adjacent hoop bar 33 and the joint reinforcing bar portion 22 of the adjacent hoop bar 35 . Alternatively, the reinforcing bar 45 may be extended in the X direction so that the reinforcing bar 45 straddles many hoop bars 33 and 35 . Also, a plurality of reinforcing steel bars 45 may be installed inside the hoop bars 33 and 35 so as to line up in the Y direction.

The present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art, including the embodiment described above. Moreover, it is also possible to configure the following modifications using the technical matters described in the above-described embodiments. You may use each structure, such as each embodiment, a modification, etc., in combination suitably.

The number of reinforcing bars (joint reinforcing bar portions 21 and 22, connecting reinforcing bar portion 23, second connecting reinforcing bar portion 25, etc.) constituting the reinforcing bar cage shown in each embodiment is limited to the example shown in the drawings. However, it can be changed as appropriate according to the design concept.

A component for improving fixing performance of the lower main steel material 11 and the upper main steel material 12 may be appropriately added to the joint structure in each embodiment. As such a component, for example, a projection or anti-slip (e.g., headed stud, PBL, etc.) may be provided on the surface of the lower main steel material 11 or the upper main steel material 12 in the vicinity of the connecting portions 11P, 12P. . Further, a fixing body may be provided at the fixing ends of the lower main steel material 11 and the upper main steel material 12 . A bearing plate may be provided at the end of the lower main steel material 11 or the upper main steel material 12 .

It is not essential that the joint reinforcing-bar portion 21 and the joint reinforcing-bar portion 22 are connected by the connecting reinforcing-bar portion 23, and the joint reinforcing-bar portion 21 and the joint reinforcing-bar portion 22 may be independent. Further, it is not essential that the small reinforcing-bar units 27 are connected to each other by the second connecting reinforcing-bar portion 25, and each small reinforcing-bar unit 27 may be independent.

In order to improve the performance of the joint portion, after installing the reinforcing bar basket on the precast concrete slab 5, a predetermined joint portion reinforcing bar may be added in place. Further, in order to improve the efficiency of installing the reinforcing bar cage on the precast concrete slab 5, the main steel members 11 and 12 may be provided with alignment projections or the like as marks to be used for positioning of the reinforcing bar cage. Further, the reinforcing bar cage may be installed on the precast concrete slab 5 using the projections or the like provided on the main steel members 11 and 12 as guides. may be Further, by embedding a predetermined steel material in the precast concrete slab 5, this steel material may be used for alignment of the reinforcing bar cage. The steel material may contribute to the reinforcement of the joint portion. For example, the steel material may be the aforementioned steel pipe 41 or reinforcing bar 45 .

Further, in each of the above-described embodiments, an example in which the joint structure of the present invention is applied to the joint of the main steel members 11 and 12 included in the composite half precast member 3 has been described, but the present invention is also applicable to the joint structure embedded in concrete. It can be applied to joints between steel materials. For example, when concrete is cast using a normal formwork in place of the precast concrete slab 5, the present invention can also be applied to joints between shape steels embedded in the concrete. In each of the above-described embodiments, the joint between the main steel materials in the composite half precast member 3 has been described as an example, but the joint structure of each of these embodiments can also be applied to the joint between reinforcing bars. In each of the above-described embodiments, the lower main steel members 11 and 12 and the upper main steel members 12 and 12 of the joint are butted against each other in the X direction, but the structure is not limited to this. That is, the lower main steel materials 11, 11 and the upper main steel materials 12, 12 related to the joint may overlap each other at the connecting portions 11P, 12P, or may be separated in the X direction.

When constructing a steel-framed concrete structure, the concrete 17 in the joint structures of the first to ninth embodiments described above may be poured separately from the other parts and may be preceded or followed. In this case, it is possible to change the strength and type of the concrete 17 of the joint from those of the other portions. For example, by increasing the strength of the concrete 17 filled in the joint portion or by mixing fibers into the concrete 17, the adhesion properties of the main steel members 11 and 12 and the joint reinforcing bar portions 21 and 22 are improved. It can be expected that the effect can be reduced.

1, 201, 301, 401, 501, 601, 701, 801, 901 ... joint structure, 3 ... composite half precast member, 5 ... precast concrete slab, 5a ... surface, 7 ... steel material unit, 11 ... lower main steel material ( Main steel material, shaped steel), 11P... Connection part, 12... Upper main steel material (second main steel material, shaped steel), 12P... Connection part, 17... Concrete, 21, 21s, 21t... Reinforcement part for joint, 21a... Fixation Part 22, 22s, 22t... Joint reinforcing bar part (second joint reinforcing bar part) 22a... Fixing part 23, 23s, 23t... Connecting reinforcing bar part, 23j... Side (connecting reinforcing bar part), 25... Third 2 connecting reinforcing bar portions, 27... small reinforcing bar units, 33, 35, 37, 39... hoop bars.

Claims (9)

A joint structure that connects shaped steels embedded in concrete,
positioned near the connection between the steel sections so as to extend longitudinally across both ends of the steel sections that are longitudinally connected to each other and together with the steel sections against the concrete; A joint structure comprising an embedded joint reinforcing bar. 2. The joint structure according to claim 1, wherein a plurality of said joint reinforcing bar portions are present in parallel with respect to one connecting portion, and said joint reinforcing bar portions are connected to each other via other reinforcing bars. . 3. The joint structure according to claim 1 or 2, wherein fixing portions for enhancing fixing performance to said concrete are provided at both ends of said joint reinforcing bar portion. 3. The joint structure according to claim 1 or 2, wherein the joint reinforcing bar portion forms part of a hoop reinforcing bar. The shaped steel is a main steel material fixed to the precast concrete slab along the surface of the precast concrete slab in a composite half precast member having a precast concrete slab,
The joint structure according to any one of claims 1 to 4, wherein the concrete is cast using the precast concrete slab as an embedded formwork. A plurality of connecting portions between the main steel members are present along the surface of the precast concrete slab so as to be aligned in a direction perpendicular to the longitudinal direction,
6. The joint structure according to claim 5, wherein a plurality of joint reinforcing bar portions respectively arranged for the plurality of connecting portions are connected to each other at positions farther from the precast concrete slab than the main steel material. The composite half-precast member further includes a second main steel material provided parallel to the main steel material at a position farther from the precast concrete slab than the main steel material,
It is arranged in the vicinity of the connecting portion between the second main steel members so as to extend in the longitudinal direction across both ends of the second main steel members that are connected to each other in the longitudinal direction, and is attached to the concrete. a second joint reinforcing bar portion embedded together with two main steel materials;
The joint structure according to claim 5, further comprising a connecting reinforcing bar section that connects the joint reinforcing bar section and the second joint reinforcing bar section. a plurality of steel material units each including the main steel material and the second main steel material are arranged in a direction orthogonal to the longitudinal direction,
a plurality of small reinforcing bar units each having the joint reinforcing bar section, the second joint reinforcing bar section, and the connecting reinforcing bar section, and arranged corresponding to each connection section between the steel material units;
A second connecting reinforcing bar portion extending in a direction intersecting with the longitudinal direction at a position farther from the precast concrete slab than the second main steel member and connecting the plurality of small reinforcing bar units. 7. The joint structure according to 7. A joint construction method for constructing a joint structure that connects shaped steels embedded in concrete,
A joint reinforcing bar portion is arranged in the vicinity of the connection portion between the shaped steels so as to extend in the longitudinal direction across both ends of the shaped steels that are connected to each other in the longitudinal direction, and the joint reinforcing bar portion and the joint reinforcing bar portion are arranged. A joint construction method, wherein the concrete is placed so as to bury the shaped steel together.

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