Precast member connection structure

Abstract

To provide a joint device and a joint structure used for connecting members used in the construction of structures, for example, to connect precast concrete members.SOLUTION: A joint device embedded in a precast member and used to connect a pair of the precast members, comprises: a connecting member for connecting the joint devices when a pair of the joint devices are butted against each other; and an anchor member fixed inside the precast member and for preventing the joint device from being pulled out of the precast member. The precast member is a segment or slab, and the anchor member is a rod-shaped member having a shape whose diameter gradually expands in a width direction, not in a thickness direction of the segment or slab, over the entire length of the anchor member from one end, which is a connecting portion with the connecting member, to the other end.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention is used to connect members used in constructing a structure, for example, to connect precast concrete members. Precast member connection structure Regarding. [Background technology]

[0002] In modern cities, when constructing structures such as buildings and various underground structures, a known technique is to construct columns and beams by transporting prefabricated concrete members to the construction site and assembling them together or to existing members. In addition, when constructing tunnels, a known construction method is to connect multiple segments adjacent to each other in the circumferential direction.

[0003] Various connecting means are used to connect various components together. For example, Patent Document 1 discloses a technology in which a joint is used as a connector for connecting segments by combining a fitting member and a fitted member. Furthermore, Patent Document 2 discloses a cotter-type joint device for fastening segments, various concrete members, and the like. These connecting means not only maintain a strong connection state, but also have the effect of facilitating workability (removal). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4344551 [Patent Document 2] Patent No. 3787576 Summary of the Invention [Problem to be solved by the invention]

[0005] As typified by the connector described in Patent Document 1, it is known to integrally mold an anchor member with a fitting body or a fitted body and produce them as a casting. However, as the structure to be constructed increases in size, it becomes necessary to increase the length of the entire part, which may make it difficult to mold them integrally as a casting. Furthermore, when the length of the connecting member is increased, it is possible to integrate the anchor member and fitting member, which are manufactured as separate parts, with screws or the like, but this raises concerns about an increase in the number of parts and rising costs.

[0006] Furthermore, in the joint device described in Patent Document 2, in order to avoid increasing the length of the anchor member, a grip portion (bearing portion) is formed at the tip of the anchor member to increase the anchoring force. However, with a configuration in which a grip portion is formed on the anchor member in this way, there is a problem in that when a large anchor pull-out force is applied to the joint device, stress is concentrated in the grip portion, causing cracks and the like in the structure (concrete, etc.).

[0007] In view of the above circumstances, an object of the present invention is to provide a coupling device that can be integrally molded as a casting by suppressing the length of the component, and that ensures anchoring force as a connecting member. [Means for solving the problem]

[0008] In order to achieve the above object, according to the present invention, a precast concrete member is embedded in the precast concrete member. A pair of coupling devices A pair of the precast members is connected to each other. Linked structure And, The coupling device is a connecting member for connecting a pair of coupling devices when the coupling devices are butted together, and an anchor member that is fixed inside the precast member and prevents the coupling device from being pulled out of the precast member, wherein the precast member is a segment or a deck slab, and the anchor member is a rod-shaped member that does not expand in the thickness direction of the segment or deck slab over the entire length of the anchor member but gradually expands in diameter in the width direction as it moves from one end, which is the connecting portion with the connecting member, to the other end. Precast member connection structure is provided.

[0009] The connecting member and the anchor member may be integrally formed cast or forged members.

[0011] Further, according to the present invention, Precast member connection structure The pair of coupling devices each serve as the connecting member. Identical configuration The cotter member is provided as a fitting member with a pair of female members butted together. The cotter member is inserted into the fitting space of the female member and connected to the female member with a bolt. The pair of precast members are connected to each other by Precast member connection structure is provided. [Effects of the Invention]

[0012] According to the present invention, a coupling device is provided that can be integrally molded as a casting by suppressing the length of the component, and that ensures anchoring force as a connecting component. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic explanatory diagram showing an example of a conventional joint device used to join precast members together. [Figure 2] FIG. 10 is a schematic explanatory view of a single member of a conventional coupling device. [Figure 3] FIG. 10 is a schematic explanatory diagram showing another form of a conventional joint device used to join precast members together. [Figure 4] FIG. 10 is a schematic explanatory view of a single member of a conventional coupling device. [Figure 5] 1 is a schematic explanatory view of a single member of a coupling device according to an embodiment of the present invention. FIG. [Figure 6] FIG. 4 is a schematic explanatory diagram relating to the pull-out resistance force F of the anchor member according to the present embodiment. [Figure 7] FIG. 1 is a schematic explanatory diagram of a first connection configuration. [Figure 8]FIG. 10 is a schematic explanatory diagram of a second connection configuration. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description may be omitted.

[0015] (Conventional coupling device) When constructing general concrete structures such as buildings and tunnels, construction is carried out by connecting multiple precast concrete members (hereinafter simply referred to as precast members).Furthermore, in flat structures such as those used to pave large areas such as airport parking lots and taxiways, construction is carried out by connecting multiple flat precast members laid on the roadbed.

[0016] FIG. 1 is a schematic explanatory diagram showing an example of a conventional joint device 1 (hereinafter referred to as the joint device 1) used to join precast concrete members, showing a pair of butt-jointed joint devices 1 (1a, 1b) assembled and joined using an H-shaped member 5. FIG. 2 is a schematic explanatory diagram of each individual member of the joint device 1, with (a) being a schematic plan view and (b) being a schematic side view. As shown in FIGS. 1 and 2, the joint device 1 is composed of C-shaped members 10 (10a, 10b) as mated members and cylindrical members 11 (11a, 11b) as anchor members. The C-shaped members 10 and cylindrical members 11 are integrated by a connecting means such as a screw mechanism to form the joint device 1.

[0017] As shown in FIG. 1, when connecting adjacent precast members P1 and P2 using a pair of coupling devices 1a and 1b, the coupling devices 1a and 1b are embedded inside each precast member P1 and P2 with the C-shaped member 10 exposed. At this time, the cylindrical member 11 is embedded inside the precast members P1 and P2 so as to be fixed (anchored) in the concrete constituting the precast members P1 and P2. Then, the H-shaped member 5 is inserted into the mating space S formed by butting together the pair of C-shaped members 10a and 10b, and bolts 14 (14a, 14b) are inserted into the bolt holes 13 (13a, 13b) formed in the H-shaped member 5 and engaged with the bottom of the C-shaped member 10. Then, a time-hardening material such as mortar or a cover member (not shown) is applied to the joint portion including the mating space S, as needed. As a result, the H-shaped member 5 is fixed in a fitted state to the C-shaped parts 10a and 10b, and the precast members P1 and P2 are joined together.

[0018] 3 is a schematic explanatory diagram showing another form of a conventional joint device 1 (hereinafter referred to as joint device 1') used to join precast members. FIG. 4 is a schematic explanatory diagram of a single member of the joint device 1', where (a) is a schematic plan view and (b) is a schematic side view. In the joint device 1' shown in FIGS. 3 and 4, the common components such as the C-shaped part 10 are the same as those shown in FIGS. 1 and 2 above, so they are denoted by the same reference numerals and their description will be omitted.

[0019] 3 and 4, the joint device 1' is provided with an anchor member 20 that is molded integrally with a C-shaped part 10, with the C-shaped part 10 provided at one longitudinal end of the anchor member 20 and a grip portion 21 at the other end. Ribs 24 are provided on the surface of the anchor member 20. Here, the anchor member 20 is generally cylindrical, and the grip portion 21 has a generally disk shape with a larger diameter than the anchor member 20 and a predetermined thickness in the longitudinal direction of the member.

[0020] (Issues with conventional coupling devices) In the conventional joint device 1 configured as described above with reference to Figures 1 and 2, the cylindrical member 11 must have a certain length due to design considerations such as the reaction force (so-called anchor force) against pullout from the concrete, resulting in a long member. The anchor force due to adhesion to concrete is calculated as the product of the circumferential area and length of the anchor part (here, the cylindrical member 11). It is known that the adhesion force of concrete is small, less than one-tenth of the compressive force of concrete, and there is also a design limit to the diameter (i.e., circumferential area) of the anchor part, so there is a demand for long anchor parts.

[0021] For this reason, it is difficult to manufacture the entire coupling device 1 as a single piece using one-piece casting, which has manufacturing dimensional constraints. Therefore, the C-shaped part 10 and the cylindrical member 11 are manufactured as separate parts as castings. As shown in Figure 2, the length L1 in the longitudinal direction of the cylindrical member 11 is designed to be, for example, approximately 450 mm.

[0022] In the coupling device 1, if the C-shaped part 10 and the cylindrical member 11 were manufactured as separate members, there would be concerns that the increased number of parts would reduce workability and increase costs. In response to these concerns, the coupling device 1' configured as described above with reference to Figures 3 and 4 was devised. According to the coupling device 1', the anchoring force is increased by providing a grip portion 21 at the end of the anchor member 20, and the entire member can be shortened. As shown in Figure 3, the longitudinal length L2 of the anchor member 20 in the coupling device 1' is designed to be, for example, approximately 200 mm. Furthermore, the entire member length of the coupling device 1' is designed to be, for example, approximately 300 mm.

[0023] On the other hand, by providing the grip portion 21, when a force is applied to pull the product out of the concrete, stress is concentrated locally around the grip portion 21 (see the dotted line in Figure 3), which raises concerns that cracks may occur in the concrete around the grip portion 21, preventing the product from fully performing its connecting function.

[0024] (Coupling device according to an embodiment of the present invention) Therefore, the present inventors have conducted extensive research into a coupling device that can be integrally molded as a casting by suppressing the length of the component, and that ensures anchoring force as a connecting component, and have devised a coupling device 30 (hereinafter also referred to as coupling device 30) according to an embodiment of the present invention, which will be described below. Figure 5 is a schematic explanatory diagram of a single component of the coupling device 30 according to an embodiment of the present invention, where (a) is a schematic plan view and (b) is a schematic side view.

[0025] 5, the joint device 30 is composed of a connecting member 35 for connecting precast members (concrete members) to each other, and an anchor member 36 that protrudes from the connecting member 35 toward the precast members (concrete members) and is embedded inside the precast members so as to be fixed (anchored) to the precast members. The connecting member 35 and the anchor member 36 may be manufactured integrally as a cast or forged member.

[0026] The shape of the connecting member 35 can be designed arbitrarily. For example, when a pair of coupling devices 30 constitute an insertion-type joint structure, the connecting member 35 may be composed of a male member as the fitting member and a female member as the fitted member. Alternatively, when a pair of coupling devices 30 constitute a so-called cotter-type joint structure, the connecting member 35 may be composed of only a female member as the fitted member, and a separate cotter member may be used as the fitting member. FIG. 5 illustrates a configuration using a C-shaped component as the fitted member (female component) as an example of the connecting member 35. Note that the configuration of the C-shaped component is similar to that of the conventional C-shaped component 10 shown in FIGS. 1 to 4, and therefore a description thereof will be omitted.

[0027] The anchor member 36 is a rod-shaped member having a conical shape that gradually widens in diameter from one end 38, which is the connecting portion with the connecting member 35, to the other end 39. The taper angle of the conical shape of the anchor member 36 can be designed arbitrarily, but it is preferable to design it so that the anchor member 36, once fixed inside the precast member, can exert a sufficient reaction force against pull-out. The longitudinal length L3 of the anchor member 36 is set to be shorter than the length L1 of the cylindrical member 11 described above.

[0028] Fig. 6 is a schematic explanatory diagram of the pull-out resistance force F of the anchor member 36 according to this embodiment, and shows the relationship between the shape of the anchor member 36 (length L3, taper angle θ, radii r, R, etc.) and the concrete compressive stress (proof stress) fck. In Fig. 6, the same components as those shown in Fig. 5 are denoted by the same reference numerals, and their description will be omitted.

[0029] As shown in Figure 6, let the cone angle (taper angle) of the anchor member 36 be θ, the radius (minimum diameter) of the anchor start point be r, and the radius (maximum diameter) of the anchor end point be R. Let us consider the case where the anchor member 36 is embedded in concrete with a friction angle of δ, and an attempt is made to pull out the anchor member 36. The wedge force W shown in the figure satisfies the relationship of the following equation (1). W = F / (sin(θ + δ)) (1) Since the horizontal component Wh of the wedge force W becomes the bearing reaction force of the concrete, the relationship between the anchor length L3, pull-out resistance force F, cone angle θ, and concrete compressive stress fck is expressed by the following equation (2). L3=α·F·cot(θ+δ) / (π·fck·(r+R)) ···(2) Here, α is a predetermined safety coefficient.

[0030] From the above formula (2), it can be seen that the pull-out resistance force F of the anchor member 36 according to this embodiment is proportional to the product of fck, tan(θ+δ), and the anchor surface area. In other words, it can be said that the concrete compressive stress fck contributes greatly to the pull-out resistance force F. This concrete compressive stress fck is, for example, 40 N / mm for general precast concrete. 2 is. On the other hand, if the anchor member has a conventional cylindrical shape, such as that described above with reference to Figures 1 and 2, the resistance that can be expected is only approximately the product of the friction force between the member and the concrete (for example, approximately 4 N / mm2) and the surface area of ​​the anchor. Therefore, it can be seen that the pull-out resistance force F of the anchor member 36 according to this embodiment is an extremely large value compared to the conventional resistance force.

[0031] The following describes the configuration when a joint structure 40 is constructed using a pair of joint devices 30 according to an embodiment of the present invention and adjacent precast members are connected to each other.

[0032] (First connection form of coupling device) First, as a first connection form, we will explain the case where adjacent precast members P1 and P2 are connected using a first coupling device 30a having a male member as the mating body and a second coupling device 30b having a female member as the mated body.

[0033] Figure 7 is a schematic diagram illustrating the first coupling configuration. The anchor member 36a of the first coupling device 30a is embedded inside the precast member P1. Here, the connecting member (male member) 35a of the first coupling device 30a is embedded in a state where it protrudes (exposed) from the precast member P1. Furthermore, the anchor member 36b of the second coupling device 30b is embedded inside the precast member P2. Here, the connecting member (female member) 35b of the second coupling device 30b is embedded inside the precast member P2.

[0034] As shown in FIG. 7, with precast members P1 and P2 adjacent to each other, connecting members 35a and 35b are butted together, and the connecting member (male member) 35a of the first coupling device 30a is fitted into the connecting member (female member) 35b of the second coupling device 30b. The connecting member 35b may have any shape as long as it has a space inside that can fit the connecting member 35a. If necessary, a time-hardening material such as mortar or a cover member (not shown) is applied to the joint, completing the connection between the precast members P1 and P2. The connecting member 35b may have the same configuration as the C-shaped part 10 described above.

[0035] (Second connection form of coupling device) Next, as a second connection form, we will explain the case where a pair of joint devices 30 are used to form a so-called cotter-type joint structure, and adjacent precast members P1 and P2 are connected using a pair of joint devices 30 having the same configuration.

[0036] FIG. 8 is a schematic diagram illustrating a second connection configuration. In this connection configuration, a pair of coupling devices 30c having the same configuration is used. The anchor member 36 of the coupling device 30c is embedded inside the precast member P1. A similar anchor member 36 of the coupling device 30c is also embedded inside the precast member P2. At this time, the connecting members 35 of each coupling device 30c, 30c, are exposed. The connecting member 35 here is a female member that serves as a mated body, and may have the same configuration as the C-shaped part 10 described above, for example.

[0037] As shown in Figure 8, a pair of connecting members 35, 35 are butted together while precast members P1 and P2 are adjacent to each other. A cotter member 50, which serves as a fitting body with an H-shaped cross section, is inserted into the fitting space S thus formed, and bolts 54 (54a, 54b) are inserted into bolt holes 53 (53a, 53b) formed in the cotter member 50 and engaged with the bottoms of the connecting members 35, 35 to complete the connection. If necessary, a time-hardening material such as mortar or a cover member (not shown) is applied to the joint portion, completing the connection between the precast members P1 and P2. It should be noted that the shape and configuration of the cotter member 50 illustrated here are merely examples, and in the coupling device 30c according to this embodiment, the shape and configuration of the cotter member 50 are arbitrary as long as they suitably connect the pair of connecting members 35, 35.

[0038] When precast members P1 and P2 are connected using the configurations related to the first and second connection forms described above, a tensile force acts between adjacent precast members P1 and P2, separating them, and even if a pull-out force is applied to anchor members 36a, 36b, sufficient anchoring force is ensured by the action of the bearing reaction force in addition to the adhesion force between anchor members 36a, 36b and the surrounding concrete. Furthermore, by giving anchor members 36a, 36b a conical shape that gradually widens in diameter from one end 38 to the other end 39, there is no risk of localized stress concentration even if a pull-out force is applied.

[0039] (Action and effect) According to the joint device 30 of this embodiment and the joint structure 40 constituted by a pair of joint devices 30a, 30b or 30c, 30c, whether the first or second connection configuration described above is adopted, sufficient anchoring force is ensured between the conical anchor member 36 and the surrounding concrete by the action of the bearing reaction force in addition to the adhesion force between the conical anchor member 36 and the surrounding concrete. In particular, compared to the conventional cylindrical member 11, while only adhesion force acts between the cylindrical member 11 and the surrounding concrete, the bearing reaction force acts in addition to the adhesion force between the conical anchor member 36 and the concrete. In other words, the pull-out force on the anchor member 36 is resolved into the adhesion force with the concrete and the bearing reaction force, thereby improving the pull-out resistance (so-called anchoring force).

[0040] Furthermore, the bearing reaction force acts on the entire anchor member 36, similar to the adhesion force. Therefore, there is no risk of localized stress concentration in the anchor member 36, and anchoring force can be ensured without increasing the length of the anchor member 36. For example, as described above with reference to FIG. 6, it is clear that the pull-out resistance force F when the anchor member 36 according to the present invention is embedded in concrete and pulled out is significantly greater than that of conventional anchor members, thereby improving anchoring force (pull-out resistance force). This allows the overall length of the coupling device 30 to be kept short and can be manufactured as a single cast or forged member, thereby reducing the number of parts and costs.

[0041] While one embodiment of the present invention has been described above, the present invention is not limited to the illustrated embodiment. It is clear that a person skilled in the art can conceive of various modifications and alterations within the scope of the ideas set forth in the claims, and it is understood that these modifications and alterations also fall within the technical scope of the present invention.

[0042] For example, in the above embodiments, a joint structure is constructed by using a male member and a female member as a joint device and fitting them together (see the first connection form), or a joint structure is constructed by using a pair of female members and a cotter member, which is a separate member, as the fitting body (see the second connection form), but the scope of application of the technology of the present invention is not limited to this. In other words, the joint device according to the present invention requires only that the anchor member have a predetermined shape, and the other components can be designed as desired.

[0043] Furthermore, while the above embodiment illustrates and describes a conical anchor member, the present invention is not limited to this. That is, the shape of the anchor member in the present invention may be any shape as long as its cross section gradually expands in diameter, and the cross section may be rectangular or elliptical. Precast concrete components to which the joint device of the present invention can be applied include various segments and deck slabs, and the cross sections of these segments and deck slabs are characterized by being narrow in the thickness direction and wide in the width direction. When applying the joint device to such precast concrete components, the cross section of the anchor member may also be rectangular or elliptical, expanding in the width direction rather than in the thickness direction. This is expected to have the effects of narrowing the remaining concrete thickness in the thickness direction and preventing cracks due to stress concentration. [Industrial Applicability]

[0044] The present invention is used to connect members used in constructing a structure, for example, to connect precast concrete members. Precast member connection structure can be applied to. [Explanation of symbols]

[0045] 1, 1'...(conventional) coupling device 5...H-shaped member 10…C type parts 11...Cylindrical member 13...Bolt hole 14...Volts 20...Anchor member (of conventional joint device) 21...Grip section 30...Coupling device (according to an embodiment of the present invention) 35...Connecting member 36...Anchor member 40...Joint structure 41...Bolt hole 42...Volts 50...Cotter member 53...Bolt hole 54...Bolt P1, P2...(a pair of) precast members

Claims

1. A connection structure in which a pair of precast members are connected to each other by a pair of joint devices embedded in the precast members, The coupling device includes a coupling member for coupling the pair of coupling devices together when the coupling devices are butted against each other; an anchor member fixed to the interior of the precast member to prevent the coupling device from being pulled out of the precast member; the precast member is a segment or a deck slab; A connecting structure for precast members, characterized in that the anchor member is a rod-shaped member having a shape that does not expand in the thickness direction of the segment or deck slab, but gradually expands in diameter in the width direction as it moves from one end, which is the connecting part with the connecting member, to the other end, over the entire length of the anchor member.

2. 2. The precast member connection structure according to claim 1, wherein the connecting member and the anchor member are integrally formed cast or forged members.

3. A connecting structure of precast members according to claim 1 or 2, Each of the pair of coupling devices has a female member having the same configuration as the connecting member, A connecting structure for precast members, characterized in that a pair of female members are butted together, a cotter member as a fitting body is inserted into the fitting space of the female members, and the cotter member is connected to the female members with a bolt, thereby connecting the pair of precast members to each other.

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