JP2023110974A - Joint structure and joint method - Google Patents

Abstract

To provide a joint structure and a joint method which can alleviate manufacturing accuracy required for a precast concrete plate and a steel material.SOLUTION: A joint structure 1 for joining a precast concrete plate 3 and a steel material unit 5 includes a steel material connection part 9 connected to a part of the precast concrete plate 3 and a part of the steel material unit 5. The steel material connection part 9 has a connection member 11 buried so as to partially project from an upper surface 3a of the precast concrete plate 3, a deviation preventing part 13 which is provided on the steel material unit 5 and is inserted into an insertion space 15 that is surrounded with the connection member 11 and is opened to the steel material unit 5 side, and a filling and solidification part 19 which is made to fill a gap between the connection member 11 and the deviation preventing part 13 in the insertion space 15, and is solidified.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a joining structure and joining method for joining a precast concrete slab and a steel material.

Conventionally, a precast synthetic member described in Patent Document 1 below is known as a technique in such a field. When manufacturing this precast composite member, a prefabricated precast concrete member is attached to a prefabricated steel panel, and a fluid solidifying agent is poured between the steel panel and the precast concrete member. Integrates steel panels and precast concrete members. When assembling the precast concrete member and the steel panel, the deformed reinforcing bar of the precast concrete member is hooked to the L-shaped notch provided in the rib of the steel panel.

JP 2010-163813 A

However, with the assembly structure described above, there is a possibility that assembly may not be possible if there is a large manufacturing error in the L-shaped notch or the deformed reinforcing bar. Therefore, manufacturing precision is required for precast concrete members and steel panels in each factory, which may hinder cost reduction and the like. SUMMARY OF THE INVENTION An object of the present invention is to provide a joining structure and a joining method that relaxes the manufacturing accuracy required for precast concrete slabs and steel materials.

A connection structure of the present invention is a connection structure for joining a precast concrete slab and a steel material, and includes a steel material connection portion that connects a part of the precast concrete slab and a part of the steel material, and the steel material connection part is a precast A connection member embedded in the precast concrete slab so that a part of it protrudes from the surface of the concrete slab toward the steel material side, and a connection member provided in the steel material so as to protrude toward the precast concrete slab side, surrounded by the connection member and opened to the steel material side. It has a non-slip portion inserted into the insertion space, and a filled solidified portion filled and solidified in a gap between the connection member and the non-slip portion in the insertion space.

The connecting member may be a tubular member projecting in the axial direction from the surface of the precast concrete slab, and the insertion space may be a hollow portion of the tubular member. The steel connection may further comprise a reinforcing bar embedded in the precast concrete slab and at least partially inserted into the insertion space. Also, the connection member may be fixed to the precast concrete slab via the reinforcing bars. Concavities and convexities may be provided on the surface of the connecting member of the steel material connecting portion. The steel material connection part may further include a loop reinforcing bar extending in a loop shape so as to circumferentially surround the connection member on the outer peripheral surface of the connection member. In the connection structure of the present invention, a plurality of steel material connection portions may exist for one steel material. In the steel connection portion, the amount of protrusion of the connection member from the surface of the precast concrete slab may be smaller than the insertion length of the anti-slip portion inserted into the insertion space.

Further, the joining method of the present invention is a method of joining a precast concrete slab and a steel material for constructing a joining structure having the aforementioned reinforcing bar at least partially inserted into the insertion space, wherein the connecting member and the reinforcing bar are installed. In the precast concrete slab manufacturing process, the connecting members are fixed to the reinforcing bars, and the concrete of the precast concrete slabs is embedded so as to embed the reinforcing bars and the connecting members. part is cast. According to this method, since the connection member is fixed to the reinforcing bar when the concrete portion is placed when the precast concrete slab is manufactured, a separate This eliminates the need to provide a spacer or the like.

ADVANTAGE OF THE INVENTION According to this invention, the joining structure and joining method which relax the manufacturing precision required for a precast concrete slab and steel materials can be provided.

(a) is an exploded perspective view showing a state before joining by the joining structure of the present embodiment, (b) is a perspective view showing a composite half precast member, and (c) is one steel material connection thereof It is sectional drawing which shows a part. 9(a) to 9(c) are diagrams showing a steel connection portion according to a modified example; FIG. (b), (d) and (f) are cross-sectional views of the vicinity of the steel connection portion according to each modification, and (a), (c) and (e) are cross-sectional views taken along the line A-A, respectively. (b) and (d) are cross-sectional views of the vicinity of the steel connection portion according to each modification, and (a) and (c) are cross-sectional views taken along line A-A, respectively. (a) and (b) are cross-sectional views of the vicinity of the steel material connection portion according to each modification, and (c) is a perspective view showing a state in which the connection member according to the modification is installed on a precast concrete slab. 9(a) to 9(d) are diagrams showing a steel material connection portion according to a modified example. FIG. FIG. 4 is a cross-sectional view showing an example in which the joint structure of the present embodiment is applied to a box culvert 100;

EMBODIMENT OF THE INVENTION Hereafter, embodiment of the joining structure and joining method which concern on this invention is described in detail, referring drawings. A joint structure 1 of this embodiment shown in FIG. 1 joins a precast concrete slab 3 and a steel material unit 5 . The precast concrete slab 3 is a plate-like member made of reinforced concrete manufactured in a factory. The reinforcing bars 21 embedded in the precast concrete slab 3 (see FIG. 3(a), etc.) are omitted from the illustration as appropriate unless necessary for explanation. The steel material unit 5 is schematically illustrated in a simplified form on the drawing, but is a unit constructed by assembling a plurality of steel materials, for example, and is manufactured in a factory.

FIG. 1(a) is an exploded perspective view showing the precast concrete slab 3 and the steel unit 5 before joining, and FIG. 1(b) is a composite half formed by joining the precast concrete slab 3 and the steel unit 5 3 is a perspective view showing a precast member 7; FIG. Such a composite half-precast member 7 is used for building a building frame, and contributes to improving the productivity of building building by making it possible to omit the shoring on the bottom surface of the formwork and the side walls of the formwork. Hereinafter, as shown in the drawings, XYZ directions that are orthogonal to each other may be defined and XYZ will be used to describe the positional relationship of each part. Moreover, when terms such as "upper/lower" and "upper/lower" are used in the description, they correspond to the upper and lower sides of the precast concrete slab 3 and the steel unit 5 in the state shown in FIG. 1(a). The precast concrete slab 3 has a flat plate shape along the XY plane, and the steel material unit 5 and the precast concrete slab 3 are joined in the Z direction.

As shown in FIG. 1(b), the joint structure 1 includes four steel connection portions 9 arranged in the Y direction. A portion of the precast concrete slab 3 and a portion of the steel unit 5 are connected at each of these four steel connection portions 9 , thereby joining the precast concrete slab 3 and the steel unit 5 . FIG. 1(c) is a cross-sectional view showing one of the steel connecting portions 9 among the above.

As shown in FIG. 1( a ), connection members 11 are installed on the upper surface 3 a of the precast concrete slab 3 at positions corresponding to the respective steel material connection portions 9 . The connection member 11 is a tubular member, and for example, a general standard steel pipe may be used as the connection member 11 . In the example of FIG. 1 , the connecting member 11 is a cylindrical member, and a common standard circular steel pipe may be used as the connecting member 11 . By adopting members of general standards in this manner, special processing of the members may be omitted, thereby reducing manufacturing costs. The connection member 11 has its lower part embedded in the precast concrete slab 3 with its cylinder axis directed in the Z direction, and its upper part facing the steel material unit 5 side upward from the upper surface 3a of the precast concrete slab 3 (in the Z direction). ) stands out. At the time of manufacturing the precast concrete slab 3, for example, concrete is poured in a state in which the connecting members 11 are appropriately arranged on the reinforcing bars 21 (see FIG. 3(a), etc.) embedded in the precast concrete slab 3 via appropriate spacers or the like. is set.

A hollow portion of the connection member 11 is a space surrounded by the connection member 11 and opened toward the steel unit 5, and is an insertion space 15 into which the anti-slip portion 13 of the steel unit 5 (to be described later) is inserted in the cylinder axis direction. The inner diameter of the connection member 11 is, for example, about 100 mm, and the amount of protrusion of the connection member 11 from the upper surface 3a is, for example, about 50 to 80 mm. The upper surface 3a of the precast concrete slab 3 also appears inside the hollow portion of the connecting member 11. As shown in FIG. The upper surface 3 a in the hollow portion of the connecting member 11 is positioned at the same height as the upper surface 3 a on the outer peripheral side of the connecting member 11 .

Further, at positions corresponding to the respective steel material connection parts 9, the steel material unit 5 is provided with anti-slip parts 13 projecting downward (in the Z direction) toward the precast concrete slab 3 side. The anti-slip portion 13 is made of, for example, a rod-shaped steel material that is welded to the surface (lower surface 5a) of the steel material unit 5 on the precast concrete slab 3 side and extends in the Z direction. In the example of FIG. 1, the anti-slip portion 13 is a stud with a head, and has a round bar-shaped main body and a slightly large-diameter head provided at the tip of the main body. The outer diameter of the anti-slip portion 13 is smaller than the inner diameter of the connecting member 11, for example about 16 to 22 mm. The amount of protrusion of the anti-slip portion 13 from the lower surface 5a of the steel material unit 5 is, for example, about 50 to 80 mm, which is slightly smaller than the amount of protrusion of the connection member 11 from the upper surface 3a of the precast concrete slab 3.

As shown in FIGS. 1(b) and 1(c), in the steel connection portion 9, the anti-slip portion 13 of the steel unit 5 is positioned in the Z direction with respect to the hollow portion (insertion space 15) of the connection member 11. inserted. Here, the lower surface 5 a of the steel material unit 5 may abut on the upper end surface of the connecting member 11 . In the steel connecting portion 9 , a gap is generated in the radial direction (XY direction) between the connecting member 11 and the anti-slip portion 13 due to the size relationship between the inner diameter of the connecting member 11 and the outer diameter of the anti-slip portion 13 . In addition, from the relationship of the amount of protrusion between the connection member 11 and the anti-slip portion 13 as described above, the amount of protrusion of the connection member 11 from the upper surface 3a of the precast concrete slab 3 is the same as that of the anti-slip portion 13 inserted into the insertion space 15. is greater than the insertion length of Therefore, the tip of the anti-slip portion 13 does not reach the upper surface 3 a of the precast concrete slab 3 that exists as the bottom surface of the insertion space 15 .

From the state in which the anti-slip portion 13 is inserted into the insertion space 15 as described above, a fluid solidifying material is injected into the gap between the connection member 11 and the anti-slip portion 13 within the insertion space 15 . The solidifying material may be injected up to a height reaching the upper edge of the connecting member 11 . In this embodiment, non-shrinkage mortar is used as the solidifying material. By solidifying the solidifying material, a filled solidified portion 19 is formed by filling and solidifying the gap between the connection member 11 and the anti-slip portion 13 in the insertion space 15 . The anti-slip portion 13 is firmly fixed to the connecting member 11 via the filling and solidifying portion 19 . In this manner, the filling and solidifying portion 19 fills the radial gap between the connection member 11 and the anti-slip portion 13 , thereby ensuring the shear resistance of the steel material connection portion 9 . Further, by using a headed stud as the anti-slip portion 13 , the pull-out resistance of the anti-slip portion 13 from the insertion space 15 is ensured, and the pull-out resistance of the steel material connection portion 9 is ensured. Accordingly, a portion of the precast concrete slab 3 and a portion of the steel unit 5 are firmly connected at the steel connecting portion 9 .

Then, the joint structure 1 in which one steel material unit 5 is joined to the precast concrete slab 3 by four steel material connection portions 9 is completed. A composite half precast member 7 is completed by joining a plurality of or a single steel material unit 5 to the precast concrete slab 3 with the joining structure 1 described above. In the example of FIG. 1, four steel material connection portions 9 are present for one steel material unit 5, but the number of steel material connection portions 9 for one steel material unit 5 may be changed as appropriate. Only one steel connecting portion 9 may exist for one steel unit 5 .

The effects of the joint structure 1 as described above will be described. In the steel material connection portion 9 of the joint structure 1, since the outer diameter of the anti-slip portion 13 is smaller than the inner diameter of the connection member 11, a gap exists in the radial direction between the anti-slip portion 13 and the inner wall surface of the connection member 11. do. Therefore, even if there is a positional error between the anti-slip portion 13 and the connecting member 11 due to a manufacturing error between the precast concrete slab 3 and the steel unit 5, the positional error can be absorbed by the radial gap. can be done. That is, it is possible to avoid an event that the anti-slip portion 13 cannot be inserted into the insertion space 15 due to the positional error.

Therefore, in the precast concrete slab 3 and the steel material unit 5, a certain degree of manufacturing error is allowed, that is, the required manufacturing accuracy is relaxed. For example, compared to a structure in which the precast concrete slab 3 and the steel unit 5 are joined via a splicing plate or directly by bolting, the manufacturing accuracy of the precast concrete slab 3 and the steel unit 5 can be relaxed. can be done. As a result, the burden of managing the manufacturing accuracy of the precast concrete slab 3 and the steel unit 5 is reduced, and as a result, the manufacturing cost of the composite half precast member 7 can be reduced. In particular, when there are a plurality of steel material connecting portions 9 for one steel material unit 5, the required accuracy of the positional relationship between the plurality of connecting members 11 and the positional relationship between the plurality of anti-slip portions 13 is relaxed. Therefore, the manufacturing accuracy required for the precast concrete slab 3 and the steel unit 5 is further relaxed.

In addition, compared to the structure using bolts to join the precast concrete slab 3 and the steel material unit 5, the number of bolt holes formed in the main steel material is reduced and the cross-sectional loss is reduced, so it is a rational design with no waste. becomes possible.

Moreover, compared to a structure in which the precast concrete slab 3 and the steel material unit 5 are joined by welding, according to the joint structure 1 of the present embodiment, the quality of the joint can be stably secured regardless of the skill of the operator. easy to do In addition, when joining by welding, for example, relatively strict rain curing of the work place is required, but according to the joining structure 1, joining work by simple rain curing is possible, that is, depending on the work environment Therefore, the joining work can be performed relatively easily.

Further, in the steel connection portion 9 of the joint structure 1 , an insertion space 15 for inserting the anti-slip portion 13 is formed surrounded by members embedded in the precast concrete slab 3 . On the other hand, as another method, it is conceivable to form a box-cut portion in the precast concrete slab 3 to serve as the insertion space 15 . However, in order to form the box-cut portion in the precast concrete slab 3, it is necessary to install a floating formwork and remove the formwork, which reduces production efficiency. In addition, the quality of the precast concrete slab 3 may be degraded due to improper filling of the concrete into the lower portion of the floating formwork, and chipping of corners when the floating formwork is removed from the mold. On the other hand, in the joint structure 1, the insertion space 15 is formed by being surrounded by the members embedded in the precast concrete slab 3. The production efficiency and quality of the concrete slab 3 are improved.

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 a modified example using the technical matters described in the above-described embodiments. The configurations of the embodiments and modifications may be used in combination as appropriate.

Each modification of the joint structure 1 will be described below. In the above-described embodiment, the connection member 11 has a cylindrical shape, but instead of this, as shown in FIG. . A general standard steel pipe may be used for the connection member 11B. Alternatively, as shown in FIG. 2B, a tapered connection member 11C (for example, a tapered steel pipe) that widens downward may be employed. The connecting member 11C may have a circular cross section or a rectangular cross section. A general standard steel pipe may be used for the connection member 11C. According to the structure using the connection member 11C, the pullout resistance of the connection member 11C from the precast concrete slab 3 is improved by the tapered shape, and the pullout resistance of the steel material connection portion 9 is improved.

Instead of the connection member 11, for example, as shown in FIG. 2(c), the insertion space 15D may be surrounded by a connection member 11D formed by combining a plurality of steel materials. In the example of FIG. 2(c), the connection member 11D is composed of four pieces of flat steel arranged in a rectangular shape in plan view. The number and shape of members constituting the are not limited. For example, the members forming the connection member 11D are not limited to flat steel, and the connection member 11D may include angle members and channel members.

Further, in order to improve the shear resistance and pull-out resistance of the steel material connecting portion 9, elements such as those shown in FIGS. 3 to 5 may be added. FIGS. 3(b), 3(d) and 3(f) are cross-sectional views of the vicinity of the steel connection portion 9 according to each modification, and the A-A cross-sectional views of FIGS. 3(a) and 3(c) are respectively ) and FIG. 3(e). Similarly, FIGS. 4(b) and 4(d) are cross-sectional views of the vicinity of the steel material connection portion 9 according to each modification, and the respective AA cross-sectional views are shown in FIGS. 4(a) and 4(c). be 5(a) and 5(b) are cross-sectional views of the vicinity of the steel material connection portion 9 according to each modification, and FIG. It is a perspective view which shows the installed state. 3 to 5, illustration of the filling and solidifying portion 19 (see FIG. 1(c)) filled in the insertion space 15 is omitted.

3(a) to 3(d), the steel connecting portion 9 has a reinforcing bar embedded in the precast concrete slab 3 and at least partially inserted into the insertion space 15. As shown in FIG. Specifically, the steel connection portion 9 shown in FIGS. 3(a) and 3(b) includes a reinforcing reinforcing bar 23A. Both ends of the reinforcing reinforcing bar 23A extend to the outside of the connecting member 11 in a plan view, and are fixed to the reinforcing bar 21 of the main body of the precast concrete slab 3 by welding, wire, or the like. A central portion of the reinforcing bar 23A is curved in an inverted U shape and inserted into the insertion space 15 through the lower end opening of the connecting member 11 . The vicinity of the upper end of the central portion of the reinforcing bar 23A protrudes upward from the upper surface 3a and passes through the side of the anti-slip portion 13, and together with the anti-slip portion 13, the filling and solidifying portion 19 (Fig. (c)). Here, two reinforcing bars 23A as described above are provided in parallel.

It should be noted that the procedure for manufacturing the precast concrete slab 3 including the reinforcing bars 23A (precast concrete slab manufacturing process) may be, for example, as follows. Before concrete is placed, a reinforcing reinforcing bar 23A is installed on the reinforcing bar 21, and the connecting member 11 is placed and fixed on the reinforcing reinforcing bar 23A so that the connecting member 11 covers the upper end of the inverted U shape of the reinforcing reinforcing bar 23A. be done. Alternatively, the connection member 11 and the reinforcing bar 23A may be integrated in advance, and may be installed and fixed to the precast concrete slab 3 before concrete is poured. As an example of fixing the connecting member 11 to the reinforcing bar 23A, for example, the connecting member 11 may be welded to the reinforcing bar 23A so that the upper ends of the two reinforcing bars 23A are easily attached to the hollow portion of the connecting member 11. It may be set in such a state that it does not come off or move. After that, the concrete portion of the main body of the precast concrete slab 3 is placed so as to embed the reinforcing bars 21, the lower portions of the reinforcing reinforcing bars 23A, and the lower portions of the connecting members 11. As shown in FIG. According to this procedure, the connecting member 11 is installed and fixed using the reinforcing reinforcing bar 23A as a frame, so that the trouble of providing a separate spacer or the like in order to appropriately arrange the connecting member 11 in the concrete formwork is omitted. be. In addition, in the steel material connection portion 9 finally completed through the manufacturing procedure of the precast concrete slab 3, the connection member 11 is fixed to the reinforcing reinforcing bar 23A inside the placed concrete or inside the filling and solidification portion 19. is in a state of In addition, the connection member 11 is fixed to the precast concrete slab 3 via the concrete portion of the precast concrete slab 3, and the connection member 11 is also fixed to the precast concrete slab 3 via the reinforcing reinforcing bar 23A. It's becoming

3(c) and 3(d), the reinforcing reinforcing bar 23B of the steel connecting portion 9 is a spiral reinforcing bar coaxial with the connecting member 11 and extending spirally. The lower end of the reinforcing reinforcing bar 23B is fixed to the reinforcing bar 21 of the main body of the precast concrete slab 3 using, for example, welding or wire. The upper end portion of the reinforcing bar 23B is inserted into the insertion space 15 through the lower end opening of the connecting member 11 and protrudes above the upper surface 3a. The upper end portion of the reinforcing bar 23B is arranged so as to wrap around the anti-slip portion 13 and is embedded together with the anti-slip portion 13 in the filling/solidifying portion 19 (see FIG. 1(c)).

3(e) and 3(f) and FIGS. 4(a) and 4(b) are formed by welding reinforcing bars to the inner wall surface of the connecting member 11 to form irregularities. 3(e) and 3(f), arc-shaped reinforcing bars 27A extending in the circumferential direction of the connecting member 11 along the XY plane are welded to the inner wall surface of the connecting member 11. As shown in FIG. Here, a plurality of (for example, four) reinforcing bars 27A are arranged in parallel in the cylindrical axis direction of the connection member 11 at regular intervals, two of which are embedded in the precast concrete slab 3, and the remaining two are inserted. It is positioned in the space 15 and embedded in the filling/solidifying portion 19 .

4(a) and 4(b), a straight reinforcing bar 27B extending in the axial direction of the connecting member 11 is welded to the inner wall surface of the connecting member 11. As shown in FIG. Here, a plurality of (for example, six) reinforcing bars 27B are arranged in the circumferential direction of the connection member 11 and exist. An upper portion of the reinforcing bar 27B is located in the insertion space 15, and a lower portion of the reinforcing bar 27B is embedded in the precast concrete slab 3. As shown in the figure, the lower end portion of the reinforcing bar 27B may be bent toward the outer peripheral side below the lower end opening of the connecting member 11 and extend in the radial direction. Also, the lower end portion of the reinforcing bar 27B may be fixed to the reinforcing bar 21 using, for example, welding or wire.

4(c) and 4(d), the steel connecting portion 9 has a loop reinforcing bar 29 extending in a loop on the outer peripheral surface of the connecting member 11 so as to surround the connecting member 11 in the circumferential direction. be. The loop reinforcement 29 has an annular shape extending in the circumferential direction of the connection member 11 along the XY plane and is welded to the outer wall surface of the connection member 11 . Here, a plurality of (for example, four) loop reinforcing bars 29 are arranged in parallel in the cylindrical axis direction of the connection member 11 at regular intervals, two of which are embedded in the precast concrete slab 3, and the remaining two are It is located between the upper surface 3a of the precast concrete slab 3 and the lower surface 5a of the steel unit.

The effects of the loop reinforcement 29 are as follows. When the anti-slip portion 13 attempts to slip out of the connecting member 11 in the axial direction, it is considered that a force is generated through the filling and solidifying portion 19 to expand the connecting member 11 in the radial direction. 4(c) and 4(d), the loop reinforcement 29 is welded to the outer peripheral surface of the steel material connection portion 9, thereby improving the rigidity of the connection member 11 and pushing and expanding it in the radial direction. Increases resistance to force. As a result, in the steel connecting portion 9, the anti-slip portion 13 can be pulled out from the connecting member 11 with improved resistance.

5(a) and 5(b), the inner wall surface of the connecting member 11 is provided with a slip stopper. A plurality of studs 31 are welded to the inner wall surface of the connecting member 11 in the steel connecting portion 9 of FIG. 5( a ). A part of the stud 31 is embedded in the precast concrete slab 3 and the remaining part is positioned in the insertion space 15 and embedded in the filling and solidification portion 19 .
A plurality of perforated steel plates 33 are welded to the inner wall surface of the connecting member 11 in the steel connecting portion 9 of FIG. 5(b). The perforated steel plate 33 has a long plate shape that rises radially inward from the inner wall surface of the connecting member 11 and extends vertically. The perforated steel plate 33 has through-holes 33a that penetrate in the plate thickness direction and are formed at regular intervals in the vertical direction. In the illustrated example, three through-holes 33a are formed in one perforated steel plate 33, but the number of through-holes 33a may be changed as appropriate. The lower part of the perforated steel plate 33 is embedded in the precast concrete slab 3 , and the upper part of the perforated steel plate 33 is positioned in the insertion space 15 and embedded in the filling and solidification portion 19 . Due to the existence of such perforated steel plates 33 , the pull-out resistance of the connection member 11 from the precast concrete slab 3 is improved, and the pull-out resistance of the steel material connection portion 9 is improved.

5(c), the connecting member 11 of the steel connecting portion 9 has a hole formed in the portion to be embedded in the precast concrete slab 3. As shown in FIG. That is, a plurality of circular through-holes 35 penetrating through the cylinder wall are formed in a portion of the connecting member 11 to be embedded in the precast concrete slab 3 . The number and arrangement of the through-holes 35 are appropriately designed. Due to the existence of such through-holes 35 , the pull-out resistance of the connection member 11 from the precast concrete slab 3 is improved, and the pull-out resistance of the steel material connection portion 9 is improved.

Further, as shown in FIG. 6(a), instead of the anti-slip portion 13 (FIG. 1(a)) composed of a stud with a head, an anti-slip portion 13B composed of a perforated steel plate dowel is attached to the steel material unit 5. may be provided. The anti-slip portion 13B has a long plate shape rising downward from the lower surface 5a of the steel material unit 5 toward the precast concrete slab 3 side. Through-holes 14a penetrating in the plate thickness direction are formed in the anti-slip portion 13B at regular intervals in the horizontal direction. Although three through-holes 14a are formed in the anti-slip portion 13B in the illustrated example, the number of through-holes 14a may be changed as appropriate. Due to the presence of the through-holes 14a, the pull-out resistance of the anti-slip portion 13B from the insertion space 15 is improved, and the pull-out resistance of the steel connecting portion 9 is improved.

Further, as shown in FIGS. 6(b) and 6(c), instead of the anti-slip portion 13 (FIG. 1(a)) composed of a stud with a head, it has a fixing body and is composed of flat steel. The anti-slip portion 13</b>C may be provided on the steel material unit 5 . FIG. 6(b) is a perspective view of the steel connecting portion 9 including the anti-slip portion 13C, and FIG. 6(c) is a sectional view thereof. The anti-slip portion 13C has a main body portion 14b in the shape of a long plate that rises downward from the lower surface 5a of the steel unit 5 toward the precast concrete slab 3, and protrudes in the X direction and/or the Y direction from the lower end of the main body portion 14b. and a formed fuser 14c. Due to the existence of this fixing body 14c, the anti-slip portion 13C has an improved resistance to pulling out from the insertion space 15, and thus the resistance to pulling out of the steel connecting portion 9 improves.

Alternatively, the bottom surface 15a of the insertion space 15 may be positioned lower than the top surface 3a of the precast concrete slab 3, as shown in FIG. 6(d). The lower end of the anti-slip portion 13 may be inserted into the insertion space 15 to a position lower than the upper surface 3a. In the steel material connecting portion 9 of this structure, the amount of protrusion of the connecting member 11 from the upper surface 3 a of the precast concrete slab 3 is smaller than the insertion length of the anti-slip portion 13 inserted into the insertion space 15 . According to this structure, by inserting the anti-slip portion 13 to a deep position in the precast concrete slab 3, the specifications of the anti-slip portion 13 are improved, and the shear resistance and pull-out resistance of the steel material connection portion 9 are improved. do.

In order to form the bottom surface 15a as described above, when the precast concrete slab 3 is manufactured, the hollow portion of the connection member 11 is filled with a temporary filling material, or the lower end opening of the connection member 11 is, for example, The concrete of the precast concrete slab 3 is placed in a state covered with a membrane-like lid member, and the temporary filling and the lid member may be removed afterward.

Further, although not shown, in the steel connecting portion 9, a plurality of anti-slip portions 13, 13B, 13C may be inserted into one insertion space 15. As shown in FIG. In addition, by providing projections on the inner wall surface and the outer wall surface of the connection members 11, 11B, 11C, 11D, and 11E, the connection members 11 to 11E can be made of the concrete of the precast concrete slab 3 and the filling and solidification portion. 19 may be enhanced.

Moreover, the connection members 11 to 11E are not limited to members made of steel, and may be made of ultra-high-strength fiber-reinforced concrete or the like. In this case, it is relatively easy to provide unevenness on the inner wall surfaces and outer wall surfaces of the connection members 11 to 11E. Further, in this case, the connecting members 11 to 11E of arbitrary dimensions and arbitrary shapes other than general standards can be manufactured relatively easily. Further, the solidifying material, which is the material of the filling and solidifying portion 19, is not limited to non-shrinking mortar, and various materials can be adopted as long as they can be fluidly injected into the insertion space 15 and then solidified. . For example, the solidifying material may be an expansive material that expands when solidified. In this case, the anti-slip portion 13 is tightened in the insertion space 15 due to the expansion of the solidifying material, thereby improving the effect of restraining the anti-slip portion 13 . In addition, the joint structure 1 is not limited to joining a steel material unit 5 made of a plurality of steel materials to the precast concrete slab 3, and can also be applied to a structure for joining a single steel material to the precast concrete slab 3. can do.

Next, an example in which the joint structure 1 as described above is applied to a box culvert 100 will be described with reference to FIG. 7 . FIG. 7 is a sectional view showing the vicinity of the top plate 102 of the box culvert 100. As shown in FIG. When constructing the top slab 102 , a composite half precast member 107 is used as a formwork structure for placing concrete for the top slab 102 . A composite half precast member 107 comprises a precast concrete slab 103 and a steel unit 105 joined by the joint structure 1 described above.

The precast concrete slab 103 is a precast member that functions as an embedded formwork for the top slab 102 having a horizontal plate shape. The steel material unit 105 includes main steel materials 111 and 112 extending horizontally over the entire top plate 102, a plurality of vertical steel materials 113 connecting the main steel materials 111 and 112 in the vertical direction, and diagonally connecting the main steel materials 111 and 112 to each other. The diagonal members 115, 115 connected to the top plate 102 and the panel members 117, 117 arranged at both ends of the top plate 102 are composed of a plurality of steel materials. The steel material unit 105 has high rigidity by assembling and constructing such a plurality of steel materials. The precast concrete slab 103 and the steel unit 105 are manufactured in separate factories in advance.

Composite half precast member 107 is constructed by vertically joining precast concrete slab 103 and steel unit 105 as described above with joint structure 1 having steel connecting portion 9 as described above. That is, for example, a connecting member 11 (see FIG. 1A) is provided on the upper surface 103a of the precast concrete slab 103, and an anti-slip portion 13 (see FIG. )) are provided, and the steel connection portion 9 is constructed. 1 to 6 may be adopted here, or the components of the steel material connection portions 9 shown in FIGS. 1 to 6 may be appropriately combined and adopted. good. Although the joint structure 1 in the illustrated example has six steel material connection portions 9, the number of the steel material connection portions 9 may be changed as appropriate.

In the construction of the top slab 102, a composite half precast member 107 is erected between both side walls 119, 119 of the box culvert 100, a precast concrete slab 103 is used as an embedded formwork, and other necessary formwork is installed to form a concrete 121. is cast. The top slab 102 is constructed with the steel unit 105 embedded in the top slab 102 and the precast concrete slab 103 exposed in the hollow portion of the box culvert 100 .

As described above, since the steel unit 105 has high rigidity, the precast concrete slab 103 is supported from below when the composite half precast member 107 is installed between the side walls 119 and 119 and the concrete for the top slab 102 is placed. shoring can be omitted. In addition, since the steel unit 105 functions as a reinforcing material for the top plate 102, the reinforcing bars of the top plate 102 can be reduced, and the reinforcement work can be reduced.

DESCRIPTION OF SYMBOLS 1... Joining structure 3, 103... Precast concrete plate 3a, 103a... Upper surface 5, 105... Steel material unit (steel material) 9... Steel material connection part 11, 11B, 11C, 11D, 11E... Connection member 13... Anti-slip part 15, 15D... Insertion space 19... Filling and solidification part 23A, 23B... Reinforcing bar 29... Loop reinforcing bar.

Claims (9)

A joint structure for joining a precast concrete slab and a steel material,
A steel material connection part that connects a part of the precast concrete slab and a part of the steel material,
The steel connecting portion is
a connection member embedded in the precast concrete slab so that a portion of the surface of the precast concrete slab protrudes toward the steel material;
an anti-slip portion provided in the steel material so as to protrude toward the precast concrete slab and inserted into an insertion space surrounded by the connecting member and opened toward the steel material;
A joining structure comprising: a filling and solidification portion filled and solidified in a gap between the connecting member and the anti-slip portion in the insertion space. 2. The joining structure according to claim 1, wherein said connecting member is a tubular member protruding from the surface of said precast concrete slab in a tubular axis direction, and said insertion space is a hollow portion of said tubular member. The joining structure according to claim 1 or 2, wherein the steel connecting portion further includes a reinforcing bar embedded in the precast concrete slab and at least partially inserted into the insertion space. The joint structure according to claim 3, wherein the connecting member is fixed to the precast concrete slab through the reinforcing bar. The joint structure according to any one of claims 1 to 4, wherein the surface of the connecting member of the steel material connecting portion is provided with unevenness. The joint structure according to any one of claims 1 to 5, wherein the steel connecting portion further comprises a loop reinforcing bar extending in a loop shape so as to circumferentially surround the connecting member on the outer peripheral surface of the connecting member. The joining structure according to any one of claims 1 to 6, wherein a plurality of said steel material connecting portions are present for one said steel material. 8. Any one of claims 1 to 7, wherein, in the steel material connection portion, a projection amount of the connection member from the surface of the precast concrete slab is smaller than an insertion length of the anti-slip portion inserted into the insertion space. The joint structure described in the paragraph. A method for joining a precast concrete slab and a steel material for constructing the joining structure according to claim 3,
A precast concrete slab manufacturing step for manufacturing the precast concrete slab on which the connection member and the reinforcing bar are installed;
In the precast concrete slab manufacturing process,
The joining method, wherein the concrete part of the precast concrete slab is placed so as to embed the reinforcing bar and the connecting member in a state where the connecting member is fixed to the reinforcing bar.

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