Method for transporting reinforcing bar cages and reinforcing bar cages

Abstract

To provide a transportation method allowing easy transportation of an extensible reinforcement cage, while preventing damage of the reinforcement cage.SOLUTION: An extensible reinforcement cage 1 has a cage body 2 formed by connecting hoops and flexible strands so as to allow variation of intersection angles. Multiple reinforcement rings 4b along the circumferential direction of the cage body 2 are provided at the cage body 2 with intervals in the axial direction of the cage body 2. In a state of the adjacent reinforcement rings 4b in the axial direction of the cage body 2 connected with each other by a connection material 5, the reinforcement cage 1 arranged so that the axial direction of the cage body 2 is the vertical direction is transported by hanging the uppermost reinforcement rings 4b.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a method for transporting a retractable reinforcing bar cage and the reinforcing bar cage. [Background technology]

[0002] One construction method for constructing cast-in-place concrete piles under low-head construction conditions is to use a telescopic reinforcing cage. Patent documents 1 to 3 describe examples of telescopic reinforcing cages, in which flexible prestressing steel strands (hereinafter referred to as strands) are used as the axial steel material that makes up the cage body instead of ordinary deformed reinforcing bars, and the strands and hoops are connected by connecting members so that the crossing angle between them is variable, allowing the cage body to expand and contract by twisting it.

[0003] To maintain the shape of the cage, multiple reinforcing rings are provided inside the cage, including at both ends, at intervals along the axial direction of the cage. The reinforcing rings are made of flat bars or steel sections (angle bars or channel steel) processed into ring shapes and are arranged around the cage.

[0004] When constructing a cast-in-place concrete pile using an extendable rebar cage, the cage is first assembled horizontally in a fully extended state at a factory, then contracted and secured before being transported to the unloading point by land transport such as a truck. The cage is then erected and extended into the borehole. Concrete is then poured into the borehole to construct the cast-in-place concrete pile. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-048519 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-132190 [Patent Document 3] Japanese Patent Application Laid-Open No. 2008-214990 Summary of the Invention [Problem to be solved by the invention]

[0006] When using telescopic rebar cages to construct deep foundation piles in mountainous areas, the cages may be transported to the construction site by land transport such as trucks, unloaded, and then lifted from a helicopter to the construction site. The unloaded cages may also be transported to the construction site while being suspended by a mobile transport frame. Additionally, the cages may also be transported by being suspended by a crane in various construction projects.

[0007] However, since the cage body easily expands when in a contracted state, if the cage body is simply lifted from the upper end, its own weight will be concentrated at the lower end of the cage body, and the connecting members at the lower end of the cage body will easily be crushed, which may damage the reinforcing bar cage.

[0008] The present invention has been made in consideration of the above problems, and aims to provide a transportation method etc. that can easily transport an extendable reinforcing bar cage while preventing damage to the reinforcing bar cage. [Means for solving the problem]

[0009] The first invention for solving the above-mentioned problems is a method for transporting an expandable reinforcing bar cage having a cage body in which ties and flexible strands are joined so that the crossing angle is variable, and the cage body is provided with a plurality of reinforcing rings along the circumferential direction of the cage body at intervals in the axial direction of the cage body, and the reinforcing rings adjacent to each other in the axial direction of the cage body are connected by connecting members, and the reinforcing bar cage is arranged so that the axial direction of the cage body is vertical, and is transported by suspending the top reinforcing ring. In response to the extension of the cage body, the connecting members change from a state in which they are disposed obliquely with respect to the axial direction of the cage body to a state in which they are disposed along the axial direction of the cage body. This is a method for transporting reinforcing bar cages, characterized by:

[0010] According to the present invention, by connecting the upper and lower reinforcing rings of the reinforcing cage with connecting members, when the reinforcing cage is lifted from the top reinforcing ring, the weight of the reinforcing cage in the section between the upper and lower reinforcing rings can be supported by the reinforcing rings below that section, and the weight of the reinforcing cage in each section is distributed and supported by each reinforcing ring. As a result, the entire weight of the reinforcing cage does not act on the bottom end of the cage body, and the connecting members of the reinforcing cage are not damaged.

[0011] before It is desirable that both ends of the connecting material be passed through holes formed in each of the reinforcing rings adjacent to each other in the axial direction of the cage body, and that nuts be tightened onto the screws at the ends of the connecting material protruding from the holes. The connecting members are attached to the reinforcing rings so that they transition from being positioned at an angle relative to the axial direction of the cage body to being positioned along the axial direction of the cage body as the cage body extends. In this invention, taking into consideration that the cage body will extend slightly and the reinforcing ring will rotate when the reinforcing cage is lifted, the connecting members are attached to the reinforcing ring by passing their ends through holes in the reinforcing ring. This allows for flexibility in the attachment while maintaining a simple configuration, allowing the connecting members to change position in response to the rotation and preventing damage to the connecting members.

[0012] It is desirable that the number of holes provided at intervals in the circumferential direction of the reinforcing ring be greater than the number of holes in the cross section of the cage body of the connecting material. This allows the connecting material to be attached by selecting an appropriate hole from among a plurality of holes, taking into consideration the change in the posture of the connecting material, etc.

[0013] The reinforcing ring is provided, for example, on the inside of the cage body. The present invention can be realized without making major changes to the structure of the retractable reinforced concrete cage, particularly the configuration of the reinforcing ring, and the connecting material can be attached by utilizing the reinforcing ring inside the cage body, which is effective in maintaining the shape of the cage body.

[0014] The second invention is an expandable reinforcing bar cage having a cage body in which hoops and flexible strands are bound together so that the crossing angle is variable, and the cage body is provided with a plurality of reinforcing rings along the circumferential direction of the cage body at intervals in the axial direction of the cage body, and the reinforcing rings adjacent to each other in the axial direction of the cage body are connected by a connecting member. In response to the extension of the cage body, the connecting members transition from a state in which they are disposed obliquely with respect to the axial direction of the cage body to a state in which they are disposed along the axial direction of the cage body. This is a reinforcing bar cage. [Effects of the Invention]

[0015] The present invention can provide a transportation method and the like that can easily transport an extendable reinforcing bar cage while preventing damage to the reinforcing bar cage. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. [Figure 2] 10 is a diagram showing the arrangement of reinforcing rings 4 (4a, 4b). FIG. [Figure 3] 1 is a diagram illustrating the production of a reinforcing bar cage 1. FIG. [Figure 4] 10A and 10B are diagrams illustrating the connection of reinforcing rings 4b by connecting materials 5. FIG. [Figure 5] 10A and 10B are diagrams illustrating the transportation of the reinforcing bar cage 1. [Figure 6] 10A and 10B are diagrams illustrating the transportation of the reinforcing bar cage 1. [Figure 7] An example of how to install connecting material 5. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0018] (1. Rebar cage 1) Fig. 1(a) is a diagram showing an expandable reinforcing bar cage 1 according to an embodiment of the present invention. As shown in Fig. 1(a), the reinforcing bar cage 1 has reinforcing rings 4 (4a, 4b) attached to a cage body 2 made of strands 21, which are flexible axial steel materials, and hoops 22.

[0019] In the cage body 2, the strands 21 and the ties 22 are connected by connecting members at their intersections so that the crossing angle between the strands 21 and the ties 22 in the vertical plane is variable, and by twisting the cage body 2 as shown by arrow A, the cage body 2 contracts as shown in Figures 1(b) and 1(c). On the other hand, by rotating the cage body 2 in the direction opposite to arrow A as shown by arrow B in Figure 1(c), the cage body 2 expands. The above connecting members are described in Patent Documents 1 to 3, and a description thereof will be omitted here.

[0020] Fig. 2(a) is a diagram showing the arrangement of the reinforcing rings 4 (4a, 4b), looking inside the cage body 2. As shown in Fig. 2(a), a plurality of reinforcing rings 4 (4a, 4b) are provided at intervals in the axial direction of the cage body 2 at both axial ends of the cage body 2 and at the intermediate portion between the both ends. Reinforcing rings 4a, 4b are provided inside and outside the cage body 2 at both ends of the cage body 2, and reinforcing ring 4b is provided inside the cage body 2 in the intermediate portion between the both ends.

[0021] 2(b) is a diagram showing the reinforcing ring 4b on the inside of the cage body 2. The reinforcing ring 4b is a ring-shaped steel material having an L-shaped cross section formed by a vertical portion 41 and a horizontal portion 42. The reinforcing ring 4b can be formed, for example, by processing an angle iron into a ring shape.

[0022] The reinforcing ring 4b on the inside of the cage body 2 is arranged along the circumferential direction of the cage body 2 with the vertical portion 41 on the outer side (the cage body 2 side), and holes 411 are formed in the vertical portion 41. The holes 411 are used to attach a rotary connecting member (not shown) that connects the reinforcing ring 4b and the strands 21 so that they can rotate in a vertical plane. The vertical portion 41 has holes 411 formed at equal intervals in the circumferential direction, the number of holes corresponding to the number of strands 21.

[0023] An example of a rotary coupling member is described in Patent Document 3, but to put it simply, it is a member having an axial member such as a stud bolt attached to the outer surface of the sleeve through which the strand 21 is inserted. The rotary coupling member can be attached to the reinforcing ring 4b by passing the axial member through the hole 411 and tightening a nut onto the tip of the axial member.

[0024] On the other hand, holes 421 are formed at equal intervals in the circumferential direction in the horizontal portion 42 of the reinforcing ring 4b. These holes 421 are used to attach connecting members, which will be described later.

[0025] A plurality of holes 421 are provided at intervals in the circumferential direction in the horizontal portion 42 of the reinforcing ring 4b. In this embodiment, a plurality of holes 421 (12 in the illustrated example) are provided at equal intervals. It is preferable that the circumferential positions of the holes 421 be different from the circumferential positions of the holes 411 in the vertical portion 41, so that the cross-sectional defects caused by the holes 411, 421 are not concentrated.

[0026] The reinforcing ring 4a on the outside of the cage body 2 has a configuration in which the vertical portion 41 and horizontal portion 42 of the reinforcing ring 4b on the inside of the cage body 2 are reversed, with the vertical portion being positioned on the inside (cage body 2 side). No holes are formed in the horizontal portion. The rest of the configuration is the same as the reinforcing ring 4b on the inside.

[0027] (2. How to transport the rebar cage 1) In this embodiment, the reinforcing bar cage 1 manufactured in a factory or the like is transported by land transport means such as a truck to the construction site or a nearby unloading point, and then the reinforcing bar cage 1 is transported, suspended by a crane or the like, to the excavation hole where the cast-in-place concrete pile will be constructed.

[0028] In a factory or the like, the reinforcing bar cage 1 is manufactured with the cage body 2 stretched (and laid horizontally) as shown in Figure 3(a), and then the cage body 2 is twisted and contracted as shown in Figure 3(b). Thereafter, as shown in Figure 3(c), adjacent reinforcing rings 4b in the axial direction of the cage body 2 are connected with connecting members 5, and the contracted cage body 2 is fastened with a fastening member (not shown) such as a band. The connecting members 5 can be threaded rebar, threaded rods, PC steel rods, etc., but threaded rebar, which can be cut to any length, is preferable in terms of workability.

[0029] 4(a) is a diagram showing the attachment portion of the connecting member 5 to the reinforcing ring 4b. The end of the connecting member 5 is passed through a hole 421 in the horizontal portion 42 of the reinforcing ring 4b, and a nut 51 is tightened onto the end of the connecting member 5 protruding from the hole 421. The diameter of the hole 421 is larger than the diameter of the end of the connecting member 5, but the outer diameter of the nut 51 is larger than the diameter of the hole 421, so that the end of the connecting member 5 is locked onto the horizontal portion 42 of the reinforcing ring 4b by the nut 51. By attaching both ends of the connecting member 5 to adjacent reinforcing rings 4b as described above, the adjacent reinforcing rings 4b are connected by the connecting member 5.

[0030] Fig. 4(b) is a diagram showing the state in which the reinforcing rings 4b are connected by the connecting material 5. As shown in Fig. 4(b), when the cage body 2 is contracted, the circumferential positions of the holes 421 in the horizontal portions 42 of the reinforcing rings 4b differ between adjacent reinforcing rings 4b, and the connecting material 5 is disposed obliquely with respect to the axial direction of the cage body 2.

[0031] Ideally, the circumferential positions of the holes 421 should be the same between adjacent reinforcing rings 4b, but as mentioned above, the cage body 2 of the reinforcing cage 1 is manufactured in an extended state and then contracted, which causes the reinforcing rings 4b to rotate as the cage body 2 twists. Since it is difficult to accurately predict the amount of rotation, in this embodiment, multiple holes 421 are provided at intervals around the circumferential direction of the reinforcing ring 4b, and the connecting members 5 are attached by selecting appropriate holes 421 that are close to each other in the circumferential direction for each of the adjacent reinforcing rings 4b, allowing the connecting members 5 to be oblique to the axial direction of the cage body 2 while transitioning to a state in which the connecting members 5 are arranged along the axial direction of the cage body 2 when the cage body 2 is extended, as described below.

[0032] For example, three to six connecting members 5 are provided in the cross section of the cage body 2 (cross section perpendicular to the axial direction of the cage body 2), and in this embodiment, four are provided. However, the number of connecting members 5 can be determined appropriately taking into consideration the steel material used for the connecting members 5, the weight of the reinforcing bar cage 1, cross-sectional loss due to perforation of the reinforcing rings 4b, etc. The number of holes 421 in the reinforcing rings 4b is set to be greater than the number of connecting members 5 in the cross section of the cage body 2.

[0033] The reinforcing bar cage 1 can be transported by land, for example, by supporting the reinforcing bar cage 1 using a cradle 10 (support base) having a core 11 and a support frame 12, and placing it on the loading platform of a truck or the like, as shown in Figure 5(a).

[0034] The mandrel 11 is a rod such as a single pipe that is arranged inside the cage body 2 along the axial direction of the cage body 2, and by abutting against the reinforcing ring 4b inside the cage body 2 from below, it can support the reinforcing bar cage 1 without damaging the connecting members between the strands 21 and the ties 22. The support frame 12 is a frame member that supports both ends of the mandrel 11, and is placed on a loading surface such as a loading platform. However, the configuration of the cradle 10 is not limited to this.

[0035] After transporting the reinforcing bar cage 1 by land to the unloading point, as shown by the arrows in Figure 5(b), a total of three points are lifted up: both ends of the core 11 of the cradle 10 and the reinforcing ring 4b at the end of the pile head side of the reinforcing bar cage 1 (corresponding to the left side of Figure 5(b)), and as shown in Figure 5(c), the end of the core 11 at the pile bottom side of the reinforcing bar cage 1 (corresponding to the right side of Figure 5(c)) is lowered and the cage body 2 is raised so that its axial direction is vertical.

[0036] Thereafter, the core rod 11 is removed, and as shown in Figure 5(d), the reinforcing bar cage 1 is lifted from a crane, helicopter, etc. by only the top reinforcing ring 4b (the reinforcing ring 4b at the end of the reinforcing bar cage 1 on the pile head side), and the reinforcing bar cage 1 is transported to the borehole. At this time, the cage body 2, which is in a contracted state, is slightly elongated although it is fastened, and as the cage body 2 and the reinforcing ring 4b rotate in a direction that eliminates the twist, the connecting material 5 transitions to a state in which it is arranged along the axial direction of the cage body 2.

[0037] Here, in this embodiment, the upper and lower reinforcing rings 4b are connected to each other by connecting materials 5, so that the weight of the reinforcing cage 1 in the section H1 from the topmost reinforcing ring 4b to the second-stage reinforcing ring 4b (meaning the number of stages counted from the top; the same applies below) is supported by the connecting materials 5 in that section H1 and the second-stage reinforcing ring 4b.

[0038] Similarly, the weight of the reinforcing bar cage 1 in section H2 from the second reinforcing ring 4b to the third reinforcing ring 4b is supported by the connecting members 5 in section H2 and the third reinforcing ring 4b, and the weight of the reinforcing bar cage 1 in section H3 from the third reinforcing ring 4b to the bottom reinforcing ring 4b is supported by the connecting members 5 in section H3 and the bottom reinforcing ring 4b. As a result, in this embodiment, the entire weight of the reinforcing bar cage 1 is not concentrated on the bottom reinforcing ring 4b.

[0039] On the other hand, on the borehole side, a stand 100 for temporarily placing the reinforcing bar cage 1 is fixed to the top end of the hole mouth P in advance, as shown in FIG. 6(a).

[0040] The stand 100 is for inserting and placing the reinforcing bar cage 1, and is configured by erecting multiple pillars 120 on fixing parts 110 that are attached to the hole opening P, and by erecting frame members 130 on top of each pillar 120. The frame members 130 have a tapered shape that narrows to a single point at the top to make it easier to insert the reinforcing bar cage 1. The pillars 120 and frame members 130 are made of single pipes or the like, and are reinforced with braces or the like as appropriate. However, the configuration of the stand 100 is not limited to this.

[0041] As shown in Fig. 6(b), the reinforcing bar cage 1 is lowered onto the stand 100 from above, and as shown in Fig. 6(c), the reinforcing ring 4b on the inside of the cage body 2 abuts against the columnar part 120, fixing the position of the reinforcing bar cage 1. Therefore, the connecting members of the strands 21 and the ties 22 will not be damaged by hitting the stand 100.

[0042] Furthermore, in the stand 100 of this embodiment, buffer materials 140 are provided at the landing position of the reinforcing bar cage 1, and the reinforcing bar cage 1 lands on the buffer materials 140, thereby suppressing the impact on the reinforcing bar cage 1 when it lands. The reinforcing bar cage 1 can be erected in a borehole by removing the connecting materials 5 and extending it, and by pouring concrete into the borehole, a cast-in-place concrete pile can be constructed.

[0043] As explained above, according to this embodiment, by connecting the upper and lower reinforcing rings 4b of the reinforcing cage 1 with the connecting members 5, when the reinforcing cage 1 is lifted from the uppermost reinforcing ring 4b, the weight of the reinforcing cage 1 in the section between the upper and lower reinforcing rings 4b can be supported by the reinforcing rings 4b below that section, and the weight of the reinforcing cage 1 in each section is distributed and supported by each reinforcing ring 4b. Therefore, the entire weight of the reinforcing cage 1 does not act on the lower end of the cage body 2, and the connecting members of the reinforcing cage 1 are not damaged.

[0044] Furthermore, this embodiment can be realized without making any major changes to the structure of the reinforcing cage 1, particularly the configuration of the reinforcing ring 4b, and the connecting material 5 can be attached by utilizing the reinforcing ring 4b on the inside of the cage body 2, which is effective in maintaining the shape of the cage body 2 and preventing damage to the connecting members of the strands 21 and the tie bars 22 when the reinforcing cage 1 is transported.

[0045] The connecting members 5 are attached to the reinforcing rings 4b so that they transition from being disposed at an angle relative to the axial direction of the cage body 2 to being disposed along the axial direction of the cage body as the cage body 2 extends. In this embodiment, taking into consideration that the cage body 2 may extend slightly and the reinforcing ring 4b may rotate when the reinforcing cage 1 is hoisted, the connecting members 5 are attached to the reinforcing ring 4b by passing the ends of the connecting members 5 through holes 421 in the reinforcing ring 4b. This allows for flexibility in the attachment while maintaining a simple configuration, allowing for changes in the position of the connecting members 5 in response to the rotation, and preventing damage to the connecting members 5. This also accommodates cases where the cage body 2 expands or contracts slightly due to vibrations during land transportation, preventing damage to the connecting members 5, the reinforcing rings 4b, the connecting rotation jig, etc.

[0046] The holes 421 in the reinforcing ring 4b are spaced apart circumferentially around the reinforcing ring 4b and are more in number than the number of connecting materials 5 in the cross section of the cage body 2, so that an appropriate hole 421 can be selected from the multiple holes 421 taking into account the above-mentioned changes in the posture of the connecting material 5, and the connecting material 5 can be attached.

[0047] However, the present invention is not limited to the above embodiment. For example, the method of attaching the connecting member 5 to the reinforcing ring 4b is not limited to the above. As shown in Figure 7(a), a split pin 52 can be inserted into the tip of the connecting member 5 protruding from the nut 51 to prevent the nut 51 from loosening. Alternatively, the nut 51 can be a double nut to prevent loosening. Also, one of the nuts 51 at both ends of the connecting member 5 can be fixed to the reinforcing ring 4b by welding or resin. In this case, the connecting member 5 can be removed when the reinforcing cage 1 is installed in the excavated hole.

[0048] Furthermore, when transporting by helicopter, for example, the reinforcing bar cage 1 is subjected to an impact when it lands. Therefore, as shown in Figure 7(b), two nuts 51 may be attached to sandwich the horizontal part 42 of the reinforcing ring 4b, so that the connecting material 5 can support the impact applied to the reinforcing bar cage 1.

[0049] In addition, in this embodiment, the reinforcing rings 4b on the inside of the cage body 2 are connected by connecting material 5, but it is also possible to provide multiple reinforcing rings 4a on the outside of the cage body 2 at intervals in the axial direction of the cage body 2, and connect adjacent reinforcing rings 4a in the axial direction by connecting material 5 in the same manner as in this embodiment.

[0050] Furthermore, although the connecting members 5 in this embodiment have threads at both ends, other connecting members 5 such as turnbuckles can also be used, and there are cases where it is not necessary to form holes 421 in the reinforcing rings 4b. For example, a gripping portion that grips the horizontal portion 42 may be attached to the horizontal portion 42 of the reinforcing ring 4b, and the gripping portions of reinforcing rings 4b adjacent in the axial direction of the cage body 2 may be rotatably connected to both ends of the connecting rod. However, in this case, the configuration becomes somewhat complicated, and there is a possibility that the gripping portion may come off due to vibrations during land transportation of the reinforcing cage 1, etc.

[0051] In this embodiment, the reinforcing bar cage 1 is lowered onto the stand 100 installed at the hole opening P, but it may also be lowered onto flat ground at the construction site. Depending on the construction site, it may also be possible to transport the reinforcing bar cage 1 by suspending it from a mobile transport frame.

[0052] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that those skilled in the art can conceive of various modifications or alterations within the scope of the technical ideas disclosed herein, and it is understood that these modifications also fall within the technical scope of the present invention. [Explanation of symbols]

[0053] 1: Reinforced concrete cage 2:Cage body 4, 4a, 4b: Reinforcement ring 5: Connecting material 10: Cradle 41: Vertical section 42:Horizontal part 51: Nut 100: Stand 411: Hole 421: Hole

Claims

1. A method for transporting an extendable reinforcing bar cage having a cage body in which ties and flexible strands are connected so that the crossing angle is variable, The cage body is provided with a plurality of reinforcing rings arranged along the circumferential direction of the cage body at intervals in the axial direction of the cage body, The reinforcing rings are connected to each other in the axial direction of the cage body by connecting members, and the reinforcing rings are arranged so that the axial direction of the cage body is vertical. The reinforcing rings are then transported by suspending the top reinforcing ring. A method for transporting reinforcing bar cages, characterized in that the connecting members transition from a state in which they are arranged diagonally with respect to the axial direction of the cage body to a state in which they are arranged along the axial direction of the cage body as the cage body is extended.

2. Both ends of the connecting member are passed through holes formed in the reinforcing rings adjacent to each other in the axial direction of the cage body, 2. The method for transporting reinforcing bar cages according to claim 1, wherein a nut is fastened to the screw at the end of the connecting material protruding from the hole.

3. 3. The method for transporting reinforcing bar cages according to claim 2, wherein the number of holes provided at intervals around the circumferential direction of the reinforcing ring is greater than the number of holes in the cross section of the cage body of the connecting material.

4. 2. The method for transporting reinforcing bar cages according to claim 1, wherein the reinforcing rings are provided inside the cage body.

5. An expandable reinforcing bar cage having a cage body in which a hoop and a flexible strand are bound together so that the crossing angle is variable, The cage body is provided with a plurality of reinforcing rings arranged along the circumferential direction of the cage body at intervals in the axial direction of the cage body, The reinforcing rings adjacent to each other in the axial direction of the cage body are connected to each other by a connecting member, A reinforcing bar cage, characterized in that the connecting members transition from a state in which they are arranged obliquely with respect to the axial direction of the cage body to a state in which they are arranged along the axial direction of the cage body in response to the extension of the cage body.

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