Joint structure of precast members

Abstract

To provide a joint structure for thin precast members that can be applied even to precast members such as thin RC segments.SOLUTION: A joint structure for precast members disclosed here comprises an outer shell portion 12 in which a male joint member 5 is formed in a shape of a plate bar with a head 8 at its tip and a female joint member 6 has a pair of clamping plates 16, 16, a pair of engaging pieces 10, 10 rotatably arranged on a back side of joint end face side end plates 13, 13 of the outer shell portion 12, biasing means 14 for biasing the engaging pieces 10, 10 toward the joint end face side end plate, and a pair of rotation control members 15, 15 whose tip portions abut against the engaging pieces 10, 10, so that the rotational movement of the engaging pieces 10, 10 is controlled by the rotation control members 15, 15.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention mainly relates to a joint structure of precast members for joining between thin precast members such as segments used for internal lining of tunnels and precast concrete slabs for floor slabs.

Background Art

[0002] In tunnel construction by the shield method, arc-shaped segments are connected in the circumferential direction along the inner peripheral surface of the excavation hole on the rear side of the shield excavator to assemble a segment ring, and this segment ring is successively connected in the tunnel axis direction as the shield excavator advances, thereby lining the tunnel.

[0003] Conventionally, the connection between these segment rings is made by connecting the segments constituting the segment ring to each other in the tunnel axis direction. The joint structure for connecting between these segments includes a pin-shaped male joint member protruding from the joint end surface of one segment to be connected to each other, and a female joint member fixed to the joint portion of the other segment. The end surfaces of both joint portions are abutted against each other, and the male joint member is inserted into the female joint member through an insertion port, and a structure is known in which the male joint member is held by the female joint member so as not to come out.

[0004] Such a joint structure includes an engaging piece that is movable in the axial diameter direction of the male joint member within the female joint member. When the male joint member is inserted into the female joint member, this engaging piece engages with an engaging groove formed on the outer peripheral portion of the male joint member by the biasing force of an elastic material such as a spring or rubber to restrict the axial movement of the pin (for example, Patent Document 1) and the like.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In recent years, many precast members such as RC segments have been developed to be thinner.

[0007] On the other hand, in the conventional technology as described above, since the engaging piece has a structure that moves in the axial diameter direction of the male joint member, the female joint member has to be enlarged accordingly. When applying it to a thin precast member such as a thin RC segment, the end of the internal reinforcing bar may have to be notched to avoid the female joint member.

[0008] Also, in the conventional technology as described above, in order to insert the male joint member into the female joint member against the biasing force of the spring member acting in the axial diameter direction of the male joint member, a high insertion force is required. On the other hand, since the engaging piece has a structure in which the male joint member is inserted from a direction substantially perpendicular to its moving direction, there is a risk that the engaging piece may be deformed by being pressed by the male joint member.

[0009] Therefore, in view of such conventional problems, the present invention has been made for the purpose of providing a joint structure for a thin precast member that can also be applied to a thin precast member such as a thin RC segment.

Means for Solving the Problems

[0010] The feature of the invention according to claim 1 for solving the conventional problems as described above is provided with a male joint member protruding from the joint end face of one precast member connected to each other and a female joint member fixed to the joint of the other precast member. By butting the two joint end faces and inserting the male joint member into the female joint member, and making the female joint member hold the male joint member so that it cannot come out, in the joint structure of the precast member in which the two precast members are connected, the male joint member is formed in a plate bar shape having a head with both sides protruding outward at the tip, and the female joint member is formed in a hollow box shape having a pair of clamping plates facing the surface of the male joint member inserted from the male joint insertion port on the joint end face side, and a pair of engaging pieces rotatably arranged on the back side of the end plate on the joint end face side of the outer shell part with the male joint insertion port sandwiched therebetween, biasing means for biasing the engaging pieces toward the joint end face side end plate side, and a pair of rotation control members that take a reaction force on the inner surface of the outer shell part at the base end part and the tip part abuts against the engaging pieces, and the rotation control members control the rotation operation of the engaging pieces.

[0011] The feature of the invention according to claim 2 is that, in addition to the configuration of claim 1, the engaging piece is provided with a guide recess into which the tip part of the rotation control member is inserted, and is configured to rotate while being guided by the rotation control member.

[0012] The feature of the invention according to claim 3 is that, in addition to the configuration of claim 1 or 2, the ends of the pair of rotation control members are connected by a connecting rod, and the connecting rod is made to abut against the back end plate of the outer shell part.

[0013] The feature of the invention according to claim 4 is that, in addition to the configuration of claim 1 or 2, the base end part of the rotation control member is fixed to the back end plate or side plate of the outer shell part.

[0014] The feature of the invention according to claim 5 is that, in addition to the configuration of claim 1 or 2, the precast member includes upper and lower reinforcing bar groups that are arranged in parallel in the member axial direction with a space in the member thickness direction, and the male joint member and the female joint member are arranged between the upper and lower reinforcing bar groups.

Advantages of the Invention

[0015] The joint structure of the precast member according to the present invention has the configuration according to claim 1, so that the engaging piece can be preferably rotated without being pivotally supported, and the thickness can be reduced.

[0016] Further, in the present invention, by having the configuration according to claim 2, the engaging piece can be stably guided by the rotation control member.

[0017] Furthermore, in the present invention, by having the configuration according to claims 3 to 4, the rotation control member can preferably obtain a reaction force against the outer shell portion.

[0018] Also, in the present invention, by having the configuration according to claim 5, the female joint member can be provided without interfering with the internal reinforcing bars.

Brief Description of the Drawings

[0019]

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Mode for Carrying Out the Invention

[0020] Next, an embodiment of the joint structure of the precast member according to the present invention will be described based on the examples shown in FIGS. 1 to 13.

[0021] In this embodiment, a case where thin RC segments are joined in the segment ring axial direction as precast members will be described as an example. In the figure, reference numerals 1 and 1 denote RC segments which are precast members.

[0022] As shown in FIG. 1, the RC segments 1 and 1 are segments formed in an arc shape by concrete, and a plurality of segments are connected in the ring circumferential direction to form an annular segment ring. By continuously arranging this segment ring in the tunnel axial direction, lining is formed in the tunnel.

[0023] These RC segments 1 and 1 have a reinforced concrete structure in which a plurality of reinforcing bars (main bars) 3, 3,... arranged in parallel in the segment axial direction at positions separated by a certain distance (cover) from both surfaces in the segment thickness direction and facing the segment circumferential direction, and a plurality of reinforcing bars (shear reinforcement bars) 4, 4,... facing in a direction orthogonal to the reinforcing bars (main bars) 3, 3,... are embedded.

[0024] In addition, the connection between the segment rings is made by connecting the segments constituting each segment ring to each other in the tunnel axis direction by a joint structure.

[0025] The joint structure for connecting the segments in the ring axis direction (tunnel axis direction) is composed of a male joint member 5 protruding from the joint end face 1a of one segment 1 to be connected to each other and a female joint member 6 fixed to the joint of the other segment 1. By butting the joint end faces 1a and 1b of both segments 1 and 1, inserting the male joint member 5 into the female joint member 6, and causing the female joint member 6 to hold the male joint member 5 so that it cannot come out, both segments 1 and 1 are connected so as not to be movable in the ring axis direction.

[0026] The male joint members 5 are arranged at intervals in the circumferential direction of the ring in a state of protruding in the ring axis direction from the joint end face 1a of the segment 1.

[0027] As shown in FIGS. 3 and 4, the male joint member 5 is formed in an elongated plate bar shape having a certain thickness by a steel plate or the like, and the surface in the thickness direction is fixed to the RC segment 1 with the thickness direction of the segment facing.

[0028] The base end side of this male joint member 5 is embedded in the concrete, and the embedded part is fixed to the reinforcing bar 7 embedded in the concrete by welding, so that the tip side protrudes from the joint end face 1a and is fixed to the segment 1.

[0029] At the tip of this male joint member 5, a head 8 with both sides protruding outward is formed, and engaging surfaces 9, 9 facing the front side in the insertion and extraction direction of the head 8 engage with engaging pieces 10, 10 of the female joint member 6 described later, so that the movement of the male joint member 5 in the extraction direction is restricted.

[0030] In addition, the head 8 is formed with guide inclined portions 8a, 8a inclined toward the tip side on both sides of the tip side, and has a narrow platform shape in plan view with the tip side.

[0031] The head 8 is formed by providing triangular notches on both sides of the male joint member 5, and the surfaces inclined at a predetermined angle of the notches and facing the front side in the insertion and extraction direction form the engaging surfaces 9, 9.

[0032] In addition, the form of the head 8 is not limited to this embodiment, and a head 8 wider than the main body portion may be integrally supported at the tip of the elongated plate-shaped main body portion.

[0033] As shown in FIGS. 5 to 8, the female joint member 6 includes a hollow box-shaped outer shell portion 12 having a male joint insertion port 11 disposed on the joint end face side, a pair of engaging pieces 10, 10 rotatably disposed in the outer shell portion 12 with the male joint insertion port 11 interposed therebetween, and biasing means 14 for biasing the engaging pieces 10, 10 toward the joint end face side end plates 13, 13. The front end face of the outer shell portion 12 is embedded in the segment 1 in a state of being exposed to the joint portion end face 1b, and the engaging surfaces 9, 9 of the head 8 of the male joint member 5 inserted from the male joint insertion port 11 are engaged with the engaging pieces 10, 10.

[0034] The female joint member 6 is also provided with a pair of rotation control members 15, 15 that take a reaction force on the inner surface of the outer shell portion 12 at the base end portion and abut the tip portion against the engaging pieces 10, 10, so that the rotation control members 15, 15 can control the rotation operation of the engaging pieces 10, 10 when the male joint member 5 is inserted.

[0035] The outer shell portion 12 includes a pair of sandwiching plates 16, 16 facing each other with a space therebetween, joint end face side end plates 13, 13 disposed on the joint end face 1b side of both sandwiching plates 16, 16, a back side end plate 17 disposed on the back side of both sandwiching plates 16, 16, and side plates 18, 18 disposed on the side portions of both sandwiching plates 16, 16. The sandwiching plates 16, 16, the joint end face side end plates 13, 13, the back side end plate 17, and both side plates 18, 18 are formed in a hollow box shape.

[0036] Both sandwiching plates 16, 16 are formed in a rectangular plate shape by a steel plate or the like, face each other at substantially the same interval as the thickness of the male joint member 5, and the male joint member 5 is inserted with the surface in the thickness direction sandwiched between the opposing surfaces of the sandwiching plates 16, 16.

[0037] The side plates 18, 18 are formed into thin plate shapes with the thickness direction facing laterally by steel plates or the like, and the upper and lower surfaces are fixed to the opposing surfaces of the clamping plates 16, 16 by welding or the like, so as to close the side portions between the two clamping plates 16, 16.

[0038] In addition, the side plates 18, 18 are arranged inside the side ends of the clamping plates 16, 16, and a concave groove surrounded by the clamping plates 16, 16 and the side plates 18, 18 is formed in the side portion of the outer shell portion 12. The tip of the reinforcing bar 19 embedded in the concrete is inserted into this concave groove, and the reinforcing bar 19 and the outer shell portion 12 are fixed by welding or the like.

[0039] The joint end face side end plates 13, 13 are formed into rectangular shapes by steel plates or the like, and the back side is fixed to the front ends of the clamping plates 16, 16 by welding or the like.

[0040] The two joint end face side end plates 13, 13 are arranged at intervals in the width direction, and a male joint insertion port 11 into which the male joint member 5 is inserted is formed between the two joint end face side end plates 13, 13.

[0041] In addition, the joint end face side end plate may be constituted by a single steel plate with the male joint insertion port 11 opened at the center.

[0042] The rear side end plate 17 is formed into a thin plate shape with the surface facing front and back, and the upper and lower surfaces are fixed to the opposing surfaces of the clamping plates 16, 16 by welding or the like, so as to close the side portions between the two clamping plates 16, 16.

[0043] The engaging pieces 10, 10 are formed into parallelogram shapes in plan view having inclined portions parallel to each other at both ends by steel materials or the like, and are arranged sandwiching the male joint insertion port 11 with one bottom side portion in contact with the joint end face side end plates 13, 13 on the back side of the joint end face side end plates 13, 13 of the outer shell portion 12.

[0044] The engaging members 10, 10 are configured such that the acute-angle portion at one end in the circumferential direction of the segment serves as a rotation fulcrum portion 10a, and the rotation fulcrum portion 10a is supported on the inner surface of the outer shell portion 12, that is, the inner surface of the side plate 18 or the back surface of the joint end surface side end plate 13, so that it can rotate within the outer shell portion 12.

[0045] Further, the engaging members 10, 10 function as guide portions 10b that guide the male joint member 5 with the inclined portions formed at the other end in the circumferential direction of the segment, and form engaging claw portions 10c that engage with the engaging surfaces 9, 9 facing the front side in the insertion and extraction direction of the head portion 8 of the male joint member 5 inserted into the female joint member 6.

[0046] Also, on the side portions opposite to the bottom side portions that contact the joint end surface side end plates 13, 13 of the engaging members 10, 10, as shown in FIGS. 7 and 8, there are provided elongated hole groove-shaped guide recesses 10d in the longitudinal direction of the engaging members 10, 10. The tip portions of the rotation control members 15, 15 are inserted into the guide recesses 10d, and the engaging members 10, 10 are guided by the rotation control members 15, 15 and perform a rotation operation.

[0047] As shown in FIG. 6, the rotation control members 15, 15 are formed in a rod shape made of a steel bar or the like. The tip portions are brought into contact with the engaging members 10, 10 by taking a reaction force on the inner surface of the outer shell portion 12 at the end portions. By being supported by the tip portions where the engaging members 10, 10 are in contact, it prevents the engaging members 10, 10 from floating upward in the forward direction of the insertion direction, and the tip portions serve as rotation fulcrums to control the rotation operation of the engaging members 10, 10.

[0048] The rotation control members 15, 15 have their base end side end portions connected by a connecting rod 20, and together with the two rotation control members 15, 15 and the connecting rod 20, they form a U shape and are accommodated in a movable state within the outer shell portion 12.

[0049] Each rotation control member 15, 15 is formed to have a length such that when the engaging pieces 10, 10 are in contact with the joint end face side end plates 13, 13 and the connecting rod 20 (base end) is in contact with the back side end plate 17, the tip is inserted into the guide recess 10d and a predetermined gap is formed between the tip and the bottom surface of the guide recess 10d. While allowing a certain rotation operation of the engaging pieces 10, 10, it is configured to prevent the engaging pieces 10, 10 from being excessively pushed into the back side.

[0050] In addition, the mode of the rotation control members 15, 15 is not limited to the above-described embodiment. As shown in FIG. 9, the base end portions of the rod-shaped rotation control members 15, 15 may be fixed to the back side end plate 17.

[0051] The rotation control members 15, 15 may be fixed by fixing the male screw portion 15a formed at the base end portion with a nut 21, or may be fixed by welding or the like.

[0052] The protruding length of the rotation control members 15, 15 from the back side end plate 17 is such that the tip is inserted into the guide recess 10d and a predetermined gap is formed between the tip and the bottom surface of the guide recess 10d. While allowing a certain rotation operation of the engaging pieces 10, 10, it is configured to prevent the engaging pieces 10, 10 from being excessively pushed into the back side.

[0053] Also, the fixing position of the base end portions of the rotation control members 15, 15 is not limited to the back side end plate 17, and may be fixed to the side plates 18, 18.

[0054] The biasing means 14 is a spring body made of an elastic wire material. Taking reaction force from the back side end plate 17, it biases the engaging pieces 10, 10 toward the joint end face side end plates 13, 13. As shown in FIGS. 6 and 8, when the male joint member 5 is not inserted, one bottom side portion of the engaging pieces 10, 10 is held in a state of being pressed against the joint end face side end plates 13, 13.

[0055] The mode of the biasing means 14 is not limited to the above-described embodiments, and may be any mode as long as it does not inhibit the insertion of the male joint member 5. In addition to the spring body made of a wire rod, a leaf spring, a coil spring, etc. may also be used. Further, the biasing means 14 may take a reaction force from, for example, the side plates 18, 18, etc. other than the back end plate 17.

[0056] To join between the RC segments 1, 1 using the joint structure of the precast member configured as described above, as shown in FIGS. 1(a) and 10, the male joint member 5 is aligned with the position of the male joint insertion port 11 of the female joint member 6, and the two segments 1, 1 are moved in the direction in which the joining end faces 1a, 1b are in contact with each other.

[0057] As shown in FIG. 11, the head 8 of the male joint member 5 is inserted into the female joint member 6 from the male joint insertion port 11, and contacts the two engaging pieces 10, 10 disposed with the head 8 sandwiching the male joint insertion port 11, and the engaging pieces 10, 10 are pushed into the back side in the female joint member 6 against the biasing means 14.

[0058] Further, when the engaging pieces 10, 10 are pushed in, the tips of the rotation control members 15, 15 come into contact with the bottom surface of the guide recess 10d of the engaging pieces 10, 10, and the base end portions (connecting rods 20) come into contact with the back end plate 17 side.

[0059] Then, when the male joint member 5 is further inserted, as shown in FIG. 12, both side portions of the head 8 of the male joint member 5 come into contact with the guiding portions 10c of the engaging pieces 10, 10, and the insertion force of the male joint member 5 acts on the guiding portion 10b, and an outward pressing force (toward the side plates 18, 18) acts on the engaging pieces 10, 10.

[0060] Also, since the engaging pieces 10, 10 are biased toward the joint end face side end plates 13, 13 by the biasing means 14, the ends of the engaging pieces 10, 10 are pushed against the joint end face side end plates 13, 13, becoming one rotation fulcrum 10a, and the tip portions of the rotation control members 15, 15 become the rotation fulcrum, and the two engaging pieces 10, 10 perform a rotation operation in a controlled state.

[0061] Then, as shown in Fig. 13, when the male joint member 5 is inserted to the position where the joint end faces 1a and 1b of both segments are joined together and the head 8 passes between both engaging pieces 10, 10, both engaging pieces 10, 10 are biased by the biasing means 14 and pushed back, and the engaging claw portions 10d at the tip of the engaging portion are inserted into the front side in the insertion and extraction direction of the head 8 of the male joint member 5 and engage with the engaging surfaces 9, 9, and the male joint member 5 is held by the female joint member 6 so as not to come out.

[0062] In the joint structure of the precast member configured in this way, since the rotation operation is controlled by the rotation control members 15, 15 and it can rotate smoothly even without being pivotally supported, the two precast members can be joined smoothly with a small insertion force.

[0063] Also, in this joint structure, since the male joint member 5 is formed in a plate bar shape and the engaging pieces 10, 10 housed in the female joint member 6 can rotate smoothly even without being pivotally supported, the entire joint structure can be made thinner and it can also be installed in narrow portions such as between the reinforcing bars embedded in both surface portions in the thickness direction of precast members such as segments.

[0064] In addition, in the above-described embodiment, the RC segments 1, 1 are described as examples of precast members, but the precast members are not limited to this embodiment and can be applied to, for example, precast floor slabs.

[0065] Also, in the above-described embodiment, the case where the tip of the rotation control member is inserted into the guide recess formed in the engaging piece 10 and abuts against the bottom of the guide recess has been described, but the guide recess may not be provided and the tip portion may be brought into contact with the surface of the engaging piece 10.

Explanation of Reference Numerals

[0066] 1 RC segment 2 RC segment 3 Reinforcing bar 4 Reinforcing bar 5 Male joint member 6 Female joint member 7 Reinforcing bar 8 Head 9 Engaging Surface 10 Engaging Piece 11 Male Joint Insertion Port 12 Outer Shell Part 13 Joint End Face Side End Plate 14 Biasing Means 15 Rotation Control Member 16 Clamping Plate 17 Rear Side End Plate 18 Side Plate 19 Reinforcing Bar 20 Connecting Rod 21 Nut

Claims

1. A precast member joint structure comprising a male joint member protruding from the joint end face of one precast member connected to each other and a female joint member fixed to the joint of the other precast member, wherein the two joint end faces are butted against each other and the male joint member is inserted into the female joint member, and the two precast members are connected by holding the male joint member in the female joint member so that it cannot come out. In this structure, the male joint member is formed in a plate-bar shape having a head portion at the tip end with both side portions protruding outward, the female joint member includes an outer shell portion formed in a hollow box shape having a pair of clamping plates facing the surface of the male joint member inserted through the male joint insertion port on the joint end face side, a pair of engaging pieces rotatably arranged on the back side of the end plate on the joint end face side of the outer shell portion with the male joint insertion port therebetween, biasing means for biasing the engaging pieces toward the joint end face side end plate side, and a pair of rotation control members having a reaction force taken on the inner surface of the outer shell portion at the base end portion and the tip end portion abutted against the engaging pieces. The rotation control member controls the rotation operation of the engaging piece. This is a characteristic of the joint structure of precast members.

2. The joint structure of a precast member according to claim 1, wherein the engaging piece is provided with a guide recess into which the tip end portion of the rotation control member is inserted, and the engaging piece rotates while being guided by the rotation control member.

3. The joint structure of a precast member according to claim 1 or 2, wherein the end portions of the pair of rotation control members are connected by a connecting rod, and the connecting rod abuts against the back end plate of the outer shell portion.

4. The joint structure of a precast member according to claim 1 or 2, wherein the base end portion of the rotation control member is fixed to the back end plate or side plate of the outer shell portion.

5. The precast member includes upper and lower reinforcing bar groups arranged in parallel in the member axial direction with a space in the member thickness direction from each other, and the male joint member and the female joint member are arranged between the upper and lower reinforcing bar groups. This is the joint structure of the precast member according to claim 1 or 2.

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