Unit for concrete ring and manufacturing method of unit for concrete ring

Abstract

To provide a unit and the like for a concrete ring capable of enhancing horizontal force transferring performance of the concrete ring.SOLUTION: A unit 1 for a concrete ring configures a concrete ring connecting a pile head part and an upper structure in a state where horizontal displacement is restrained while relative rotational displacement between both is allowed. The unit 1 for the concrete ring comprises a steel plate ring 2-1 placed along the inner peripheral surface of the concrete ring; and a spiral reinforcement 3-1 arranged along the outer surface of the steel plate ring 2-1 so as to be in contact with the outer surface. The spiral reinforcement 3-1 functions as a reinforcement member to reinforce the concrete ring against horizontal force applied from the pile head part or the upper structure.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a concrete ring unit used to join a pile head to a superstructure. [Background technology]

[0002] Known methods for joining the pile heads of precast piles or cast-in-place concrete piles to superstructures such as pile caps include a method using anchoring reinforcement and the CP method (capping pile method or cabten pile method) using concrete rings.

[0003] In the former method, which uses anchor bars, the pile head and superstructure are rigidly connected, but in the latter CP method, there are no anchor bars connecting the pile head and superstructure, so the two are not rigidly connected and relative rotational displacement between the pile head and superstructure is permitted. This reduces the stress on the pile head when bending occurs, preventing damage to the pile head.

[0004] The basic structure of the CP method is to cover the pile head of a pile 20 with a concrete ring 100 and embed the upper part of the concrete ring 100 in the concrete of the superstructure 30, as shown in Fig. 11, and the relative horizontal displacement between the pile head and the superstructure 30 is restrained by the concrete ring 100. The CP method is structured so that the horizontal force generated in the pile head due to an earthquake or the like is transmitted to the concrete ring 100, and the overlapping portion in the height direction of the pile head and the concrete ring 100 is the range in which the horizontal force can be transmitted. This horizontal force is transmitted to the superstructure 30 via the concrete ring 100.

[0005] Patent document 1 describes a concrete ring unit, which is a component of a concrete ring, in which a cylindrical inner ring and an outer ring are connected by a connecting material, and the concrete ring is formed by pouring concrete between the inner ring and the outer ring. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 5830441 Summary of the Invention [Problem to be solved by the invention]

[0007] In recent years, pile performance has improved and the number of piles supporting buildings has decreased compared to the past, resulting in a larger horizontal force acting on each pile. In addition, the earthquake load that must be taken into consideration in the design has also increased. Therefore, it is necessary to improve the horizontal force transmission performance of the concrete ring.

[0008] The present invention has been made in consideration of the above problems, and has an object to provide a unit for a concrete ring, etc., which can improve the horizontal force transmission performance of a concrete ring. [Means for solving the problem]

[0009] The first invention for solving the above-mentioned problems is a unit for a concrete ring that constitutes a concrete ring that joins the pile head and superstructure in a state that restrains horizontal displacement while allowing relative rotational displacement between the two, and is characterized in having a tubular member arranged along the inner surface of the concrete ring, and a reinforcing member that is provided along the outer surface so as to contact the outer surface of the tubular member and for reinforcing the concrete ring against horizontal forces applied from the pile head or superstructure.

[0010] In the concrete ring unit of the present invention, a reinforcing member that reinforces the concrete ring against horizontal forces applied to the concrete ring from the pile head or superstructure is provided along the outer surface of the tubular member so as to be in contact with the outer surface of the tubular member. This improves the concrete ring's resistance to horizontal forces, enabling the concrete ring to transmit large horizontal forces.

[0011] The reinforcing member is, for example, a spiral rib arranged in the circumferential direction of the tubular member. This allows the compressive force generated in one part of the concrete ring due to horizontal force to be transmitted to the other side of the concrete ring by the tensile stress of the spiral reinforcement, etc., thereby avoiding the concentration of compressive force in the concrete ring, and thereby increasing the concrete ring's resistance to horizontal forces.

[0012] The reinforcing member may be a rib fixed to an outer surface of the tubular member and extending in the axial direction of the tubular member. In this case, the ribs resist the shear force generated in the axial cross section of the concrete ring due to the horizontal force, thereby increasing the resistance of the concrete ring to the horizontal force.

[0013] It is desirable that the outer surface of the tubular member be provided with a positioning member for positioning the spiral grooves along the outer surface of the tubular member. This allows the spiral ribbing to be securely held on the outer surface of the tubular member.

[0014] The ribs may be provided with holes or notches for the placement of reinforcing bars to be embedded within the concrete ring. This allows the reinforcing bars of the concrete ring to be securely held in place.

[0015] The second invention is a method for manufacturing a unit for a concrete ring, characterized in that the tubular member is arranged with its axial direction facing up and down, and the spiral reinforcement is installed by dropping the spiral reinforcement from above the tubular member along the outer surface of the tubular member. In the second invention, the tubular member is positioned with its axial direction facing up and down, and the spiral ribs are dropped into the tubular member from above, thereby making it possible to easily install the spiral ribs along the outer surface of the tubular member. Effect of the Invention

[0016] According to the present invention, it is possible to provide a unit for a concrete ring, etc., which can improve the horizontal force transmission performance of a concrete ring. [Brief description of the drawings]

[0017] [Figure 1] FIG. 2 is a perspective view showing a concrete ring unit 1. [Diagram 2] A diagram showing a cross section of unit 1. [Diagram 3] A diagram explaining how to make unit 1. [Figure 4] A diagram explaining how to make unit 1. [Diagram 5] 2A to 2C are diagrams illustrating a method for forming the concrete ring 10. [Figure 6] A diagram showing the joint between the pile head and the superstructure 30 using a concrete ring 10. [Figure 7] FIG. [Figure 8] A diagram showing unit 1a. [Figure 9] A diagram showing the joint between the pile head and the superstructure 30 by the concrete ring 10a. [Figure 10] FIG. 13 is a diagram showing ribs 8a and 8b. [Figure 11] A diagram showing the joint between the pile head and the superstructure 30 using a concrete ring 100. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0019] [First embodiment] (1. Concrete ring unit 1) Figure 1 is a diagram showing a unit 1 for a concrete ring (hereinafter referred to as the "unit") relating to the first embodiment of the present invention, and Figures 2(a) and (b) are diagrams showing cross sections of the unit 1 taken along lines aa and bb in Figure 1, respectively.

[0020] Unit 1 is a component that makes up the above-mentioned concrete ring, and includes steel plate rings 2 (2-1, 2-2), spiral reinforcement 3 (3-1, 3-2), positioning members 4, connecting members 5 (5-1, 5-2), and retaining members 7. Additionally, anchoring reinforcement 6 is placed inside the spiral reinforcement 3-2. Note that "inside" refers to the center side of the plane of unit 1, and the opposite side is referred to as "outside."

[0021] The steel plate ring 2 is a cylindrical member made of ring-shaped steel plates, and is arranged concentrically inside and outside. The above-mentioned spiral reinforcement 3, positioning member 4, connecting member 5, anchoring reinforcement 6, and retaining member 7 are arranged between the inner steel plate ring 2-1 and the outer steel plate ring 2-2.

[0022] The spiral reinforcement 3 is a reinforcing bar that reinforces the concrete ring, and in this embodiment, a spiral reinforcing bar or PC steel rod is used. The spiral reinforcement 3 is arranged along the circumferential direction of the steel plate ring 2, and is provided around the entire circumference of the steel plate ring 2.

[0023] The spiral reinforcement 3 is also arranged on the inside and outside, with the inner spiral reinforcement 3-1 being provided along the outer surface of the inner steel plate ring 2-1 so as to be in contact with said surface, and the outer spiral reinforcement 3-2 being arranged in the middle portion between the inner and outer steel plate rings 2-1 and 2-2.

[0024] The positioning member 4 is a member for arranging the inner spiral muscle 3-1 along the inner steel plate ring 2-1, and a plurality of positioning members are provided at approximately equal intervals in the circumferential direction of the steel plate ring 2-1. The positioning member 4 in this embodiment is formed by bending an elastic band-shaped steel plate, and has a main body 41 with a U-shaped cross section in the vertical direction, and a fixing piece 42 extending vertically from the main body 41. The fixing piece 42 is fixed to the outer surface of the steel plate ring 2-1 by using a rivet 43, and the spiral muscle 3-1 is arranged between the outer surface of the steel plate ring 2-1 and the recess of the main body 41.

[0025] The connecting members 5 are arranged between the inner and outer steel plate rings 2-1, 2-2 so as to connect both rings. The connecting members 5 are formed from steel plates, and both ends thereof are fixed to the inner and outer steel plate rings 2-1, 2-2, respectively, by welding, bolts, etc. The connecting members 5 are provided in two tiers, upper and lower, and a plurality of these connecting members 5 are arranged at approximately equal intervals in the circumferential direction of the steel plate ring 2. The positions of the connecting members 5 in the circumferential direction of the steel plate ring 2 are set so as to avoid the positions of the positioning members 4.

[0026] The anchoring bars 6 are reinforcing bars that protrude upward from the concrete ring and are embedded in a superstructure such as a pile cap. In this embodiment, the anchoring bars 6 are placed through holes 51 in the upper connecting material 5-1, and their lower ends are placed in recesses 52 in the lower connecting material 5-2. This allows the anchoring bars 6 to be held in place and their positions to be fixed.

[0027] The outer spiral reinforcement 3-2 is placed between the upper and lower connecting members 5-1, 5-2 so as to be in contact with the outside of the anchor reinforcement 6. The retaining member 7 is a rod-shaped member for holding the spiral reinforcement 3-2, and is placed so as to connect the upper and lower connecting members 5-1, 5-2 outside the anchor reinforcement 6 by fixing its lower end to the lower connecting member 5-2 and passing its upper end through the hole 53 of the upper connecting member 5-1. By clamping the spiral reinforcement 3-2 between the anchor reinforcement 6 and the retaining member 7, the spiral reinforcement 3-2 is held outside the anchor reinforcement 6 and its position is fixed.

[0028] (2. How to make Unit 1) The unit 1 is fabricated in advance in a factory or the like. When fabricating the unit 1, as a preliminary step, the lower fixed piece 42 of the positioning member 4 is fixed to the steel plate ring 2-1 in advance as shown in Fig. 3(a). The interior angle α of the lower bent portion 411 of the main body 41 of the positioning member 4 is set so that a gap is secured between the upper fixed piece 42 and the steel plate ring 2-1 to allow the spiral reinforcement 3-1 to pass through when the lower fixed piece 42 is fixed to the steel plate ring 2-1, and is set to a predetermined value exceeding 90°, for example.

[0029] On the other hand, the spiral reinforcement 3-1 is tied in advance with tie materials such as cable ties so that the rebars can be disassembled one by one starting from the bottom. That is, as shown in Fig. 3(b), where n is the number of rebar stages in the spiral reinforcement 3-1, tie materials 32 are attached to tie the rebars of the 2nd, 3rd, ..., n-1st, and nth stages from the top. By removing these tie materials 32 in the order of tie materials 32 binding the rebars of the nth stage, tie materials 32 binding the rebars of the n-1st stage, ..., tie materials 32 binding the rebars of the 3rd stage, tie materials 32 binding the rebars of the 2nd stage, the spiral reinforcement 3-1 can be disassembled one by one starting from the bottom.

[0030] After the above preparations are completed, the steel plate rings 2-1 are arranged with their axial directions facing up and down, and the spiral reinforcement 3-1 is suspended above the steel plate rings 2-1, as shown in Fig. 4(a). Then, as described above, the binding material 32 is removed and the spiral reinforcement 3-1 is disassembled one layer at a time from the bottom. As shown in Fig. 4(b), the disassembled reinforcing bars are dropped into the main body 41 of the positioning member 4 and arranged so as to contact the outer surface of the steel plate ring 2-1. The reinforcing bars are then fixed to the outer surface of the steel plate ring 2-1 by adhesive, welding, or the like. The fixing position of the reinforcing bars in the circumferential direction of the steel plate ring 2-1 is set to a position different from that of the positioning member 4.

[0031] In this way, all the reinforcing bars of the spiral reinforcement 3-1 are arranged along the outer surface of the steel plate ring 2-1 as shown in Fig. 4(c). After that, the upper fixing piece 42 of the positioning member 4 is fixed to the steel plate ring 2-1 as shown in Fig. 4(d). The spiral reinforcement 3-1 is arranged side by side with no gaps in the axial direction of the steel plate ring 2-1.

[0032] The subsequent steps are the same as those shown in Fig. 2 of the above-mentioned Patent Document 1. That is, one end of the lower connecting material 5-2 to which the retaining material 7 is fixed is attached to the steel plate ring 2-1, and the outer spiral reinforcement 3-2 is placed on the connecting material 5-2, after which one end of the upper connecting material 5-1 is fixed to the steel plate ring 2-1. Then, the outer steel plate ring 2-2 is attached and placed to the other ends of the upper and lower connecting materials 5-1 and 5-2.

[0033] (3. Concrete Ring 10) The concrete ring is formed by pouring concrete between the inner and outer steel plate rings 2-1 and 2-2 of the unit 1. The anchor bars 6 are installed immediately before pouring the concrete.

[0034] Pouring of concrete may be performed in a factory or the like, but in this embodiment, as shown in Fig. 5(a), the unit 1 is transported to the site and placed on the leveling concrete 21 around the pile head so as to cover the pile head of the pile 20. The pile 20 is, for example, a precast pile or a cast-in-place concrete pile, but is not limited to this.

[0035] After arranging the unit 1, the above-mentioned anchoring reinforcement 6 is installed, and concrete Con is poured between the steel plate rings 2-1 and 2-2 as shown in Fig. 5(b) to form the concrete ring 10. The inner steel plate ring 2-1 is arranged along the inner circumferential surface of the concrete ring 10, and the outer steel plate ring 2-2 is arranged along the outer circumferential surface of the concrete ring 10. In addition, the spiral reinforcement 3-1 and 3-2 are embedded in the concrete Con, and are arranged in a range that straddles the top surface of the pile head in the height direction.

[0036] Once the concrete ring 10 has been formed in this manner, concrete for the superstructure 30 is poured as shown in Fig. 6. The superstructure 30 is, for example, a pile cap, but is not limited to this and may be a foundation beam or the like. The concrete for the superstructure 30 is also poured inside the concrete ring 10, and the top of the concrete ring 10 is embedded in the concrete of the superstructure 30. The concrete ring 10 joins the pile head and the superstructure 30 in a state that allows relative rotational displacement between the two while restricting horizontal displacement.

[0037] In this joint, when the pile 20 receives a horizontal force and moves horizontally as indicated by arrow A, a gap occurs at the interface between the pile head and the superstructure 30, and the concrete ring 10 is pushed horizontally. As a result, the compressive force acting on a part of the concrete ring 10 (the left part in the example of Fig. 6) is transmitted to the opposite side of the concrete ring 10 as indicated by arrow B via the tensile stress of the spiral reinforcement 3-1 and the steel plate ring 2-1, and on the opposite side, a compressive force C acts from the concrete ring 10 to the superstructure 30. As a result, it is possible to avoid concentration of compressive force on the concrete ring 10, and the resistance of the concrete ring 10 to horizontal forces is improved.

[0038] In this way, the spiral reinforcement 3-1 functions as a reinforcing member that reinforces the concrete ring 10 against the horizontal force applied from the pile head and improves the resistance to the horizontal force. This also applies when the superstructure 30 receives a horizontal force and moves horizontally, and the horizontal force is applied from the superstructure 30 to the concrete ring 10.

[0039] As described above, in the unit 1 of the first embodiment, the spiral reinforcement 3-1 that reinforces the concrete ring 10 against the horizontal force applied to the concrete ring 10 from the pile head and superstructure 30 is provided along the outer surface of the steel plate ring 2-1 so as to be in contact with said outer surface. This unit 1 transmits the compressive force generated in a part of the concrete ring 10 due to the horizontal force to the opposite side of the concrete ring 10 by the tensile stress of the spiral reinforcement 3-1, etc., and prevents the concentration of the compressive force in the concrete ring 10, thereby increasing the resistance of the concrete ring 10 to the horizontal force. This enables the concrete ring 10 to transmit a large horizontal force.

[0040] In this embodiment, the positioning member 4 can reliably hold the spiral reinforcement 3-1 on the outer surface of the steel plate ring 2-1.

[0041] In addition, in this embodiment, the spiral reinforcement 3-1 can be easily installed along the outer surface of the steel plate ring 2-1 by dropping the spiral reinforcement 3-1 onto the steel plate ring 2-1 with the axial direction of the steel plate ring 2-1 being up and down.

[0042] However, the present invention is not limited to the above embodiment. For example, in the above embodiment, the spiral reinforcement 3-1 is used as the reinforcing member, but instead, annular hoop reinforcement may be arranged in multiple layers above and below. In some cases, the outer steel plate ring 2-2 and the connecting material 5 may be omitted.

[0043] Furthermore, the positioning member 4 is not limited to the above-mentioned configuration. For example, as shown in Fig. 7(a), the positioning member 4a may be composed of upper and lower components 40. Each component 40 has a fixing piece 42 provided at one end of a main body 41a having an L-shaped vertical cross section, and is relatively easy to manufacture.

[0044] In this case, as shown in Fig. 7(b), the lower component 40 is placed with the main body 41a facing up, and the lower fixing piece 42 is fixed to the steel plate ring 2-1. As described above, the spiral reinforcement 3-1 is dropped inside the main body 41a and placed so as to contact the outer surface of the steel plate ring 2-1. Then, as shown by the arrow, the main body 41a of the upper component 40 is placed on the upper part of the main body 41a of the lower component 40, and the fixing piece 42 above the main body 41a is fixed to the steel plate ring 2-1. By determining the shape of the component 40 so that the gap between the steel plate ring 2-1 and the main body 41a of the lower component 40 is approximately equal to the diameter of the spiral reinforcement 3-1, the work of fixing the spiral reinforcement 3-1 to the steel plate ring 2-1 with an adhesive or the like is not required.

[0045] Furthermore, the reinforcing members for the horizontal force of the concrete ring 10 are not limited to the spiral reinforcement 3-1 and the hoop reinforcement. Below, an example of another reinforcing member will be described as the second embodiment. The second embodiment will be described in terms of the differences from the first embodiment, and the same reference numerals will be used in the drawings to omit the description of similar points.

[0046] [Second embodiment] Fig. 8(a) is a diagram showing a unit 1a according to a second embodiment of the present invention, and Fig. 8(b) is a diagram showing a cross section of unit 1a taken along line cc in Fig. 8(a). Unit 1a of the second embodiment differs from unit 1 of the first embodiment mainly in that ribs 8 are used as reinforcing members against horizontal forces of the concrete ring.

[0047] The rib 8 is a rectangular plate-shaped member made of steel plate or the like, and its long sides are fixed to the outer surface of the steel plate ring 2-1 by welding or the like, and is arranged so as to extend in the axial direction of the steel plate ring 2-1. A plurality of ribs 8 (e.g., four or more) are arranged at approximately equal intervals in the circumferential direction of the steel plate ring 2-1. The spiral muscles 3-2 are arranged so as to abut against the outside of the rib 8, and the rib 8 also has a positioning function when arranging the spiral muscles 3-2.

[0048] Fig. 9 is a diagram showing the joint between the pile head and the superstructure 30 by the concrete ring 10a formed by using the above-mentioned unit 1a. When the pile 20 receives a horizontal force and moves horizontally as shown by the arrow A, a shift occurs at the interface between the pile head and the superstructure 30, and in the axial cross section of the concrete ring 10a, a large shear force is generated in the middle part in the height direction due to this horizontal force. The rib 8 reinforces the concrete ring 10a against the shear force, improving resistance to the horizontal force.

[0049] In this way, the rib 8 functions as a reinforcing member for reinforcing the concrete ring 10a against the horizontal force applied from the pile head by resisting the above-mentioned shear force. This also applies when the superstructure 30 receives a horizontal force and moves horizontally, and the horizontal force is applied from the superstructure 30 to the concrete ring 10a.

[0050] As described above, in the unit 1a of the second embodiment, the ribs 8 resist the shear force generated in the axial cross section of the concrete ring 10a due to the horizontal force applied from the pile head and the superstructure 30, thereby increasing the resistance of the concrete ring 10a to horizontal forces and enabling the concrete ring 10a to transmit large horizontal forces.

[0051] The rib 8 is not limited to the one described above. For example, as shown in rib 8a in Fig. 10(a), holes 81 for arranging the spiral reinforcement 3-2 may be provided, which makes it possible to reliably hold the position of the spiral reinforcement 3-2. Alternatively, as shown in rib 8b in Fig. 10(b), instead of holes 81, slit-like notches 82 formed from the outside may be provided, which makes it possible to reliably hold the position of the spiral reinforcement 3-2 and also makes it easier to arrange the spiral reinforcement 3-2 before attaching the outer steel ring 2-2.

[0052] In addition, after placing the spiral reinforcement 3-2 in the notch 82, by placing backing plates 83 on the outside of the spiral reinforcement 3-2 on both sides of the rib 8b as shown in Fig. 10(c), the position of the spiral reinforcement 3-2 can be more reliably maintained. Note that in the example of Fig. 10(a) to (c), the width of these ribs 8a, 8b is equal to the distance between the inner and outer steel plate rings 2-1, 2-2, and it is also possible to connect the inner and outer steel plate rings 2-1, 2-2 with the ribs 8a, 8b instead of the above-mentioned connecting members 5-1, 5-2.

[0053] Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, the present invention is not limited to the above examples. It is clear that a person skilled in the art can come up with various modified or altered examples within the scope of the technical ideas disclosed in this application, and it is understood that these also naturally belong to the technical scope of the present invention. [Explanation of symbols]

[0054] 1, 1a: Concrete ring unit 2, 2-1, 2-2: Steel plate ring 2, 3-1, 3-2: Spiral muscles 4, 4a: Positioning member 5, 5-1, 5-2: Connecting material 6: Fixation muscle 7: Retaining material 8, 8a, 8b: Ribs 10, 10a, 100: Concrete ring 20:Pile 30:Superstructure

Claims

1. A concrete ring unit that constitutes a concrete ring that joins the pile head and the superstructure in a state that allows relative rotational displacement between them while restricting horizontal displacement; A cylindrical member disposed along an inner peripheral surface of the concrete ring; a reinforcing member provided along the outer surface of the tubular member so as to be in contact with the outer surface of the tubular member, for reinforcing the concrete ring against a horizontal force applied from the pile head or a superstructure; A unit for a concrete ring, comprising:

2. 2. The concrete ring unit according to claim 1, wherein the reinforcing member is a spiral reinforcement arranged in the circumferential direction of the tubular member.

3. 2. A unit for a concrete ring according to claim 1, wherein said reinforcing member is a rib fixed to an outer surface of said tubular member and extending in the axial direction of said tubular member.

4. 3. A unit for a concrete ring according to claim 2, characterized in that a positioning member is provided on an outer surface of said tubular member for positioning said spiral reinforcement along the outer surface of said tubular member.

5. 4. The concrete ring unit according to claim 3, wherein said ribs are provided with holes or notches for accommodating reinforcing bars to be embedded in said concrete ring.

6. A method for manufacturing a concrete ring unit according to claim 2, comprising the steps of: A method for manufacturing a unit for a concrete ring, characterized in that the tubular member is arranged with its axial direction facing up and down, and the spiral reinforcement is installed by dropping the spiral reinforcement from above the tubular member along the outer surface of the tubular member.

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