Flexible joint

Abstract

To provide a flexible joint capable of suppressing local strain generated in an expansion member at low cost.SOLUTION: A flexible joint 1 is provided in a joint part 61 of a concrete structure 60. The flexible joint 1 includes the expansion / contraction member 10 having the expansion / contraction portion 11 that expands and contracts the flexible joint 1 and the extension portions 13 that extend from both end portions of the expansion / contraction portion 11 and have the pressing portions 12, the expansion / contraction portion 11 being provided so as to straddle the joint portion 61, and the pressing members 40 that are disposed on both sides of the joint portion 61 and press the pressing portions 12 against the concrete structure 60. A bent portion 13a that is bent is formed in the extending portion 13, and the extendable member 10 is provided in a state of being deformed so as to eliminate the bending of the bent portion 13a by being pressed by the pressing member 40.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a flexible joint. [Background technology]

[0002] Flexible joints are provided in the joints of concrete structures such as waterways, water tanks, and underground culverts such as utility sewer systems to stop water flow and to allow for uneven settlement of the concrete structures on both sides of the joint, displacement during earthquakes, etc. For example, Cited Document 1 discloses a flexible joint consisting of an expansion member that constitutes the main body of the flexible joint, a clamp for the expansion member, and a fastener. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-106294 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the water pressure from the water flowing out of the joints acts on the expansion member of Patent Document 1, large local strains tend to occur at the boundary between the area of ​​the expansion member held down by the clamp and the area where the water pressure acts. Such local strains are also likely to occur when the concrete structure is displaced. To reduce local strains, methods have been used such as placing reinforcing fabric inside the expansion member or using steel materials to hold down the deformation of the expansion member, but these methods increase costs.

[0005] The present invention has been made in light of these problems, and has as its object to provide a flexible joint that can suppress local strain occurring in an expandable member at low cost. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the flexible joint of the present invention is a flexible joint that is installed in a joint portion of a concrete structure, and comprises an expansion / contraction section that expands and contracts the flexible joint, and an extension section that extends from both ends of the expansion / contraction section and has a pressing section, the expansion / contraction section being installed so that it straddles the joint portion, and a pressing member that is arranged on both sides of the joint portion and presses the pressing section against the concrete structure, and a bent portion is formed in the extension portion, and the expansion / contraction member is installed in a deformed state so that the bending of the bent portion is eliminated by the pressure from the pressing member.

[0007] The bent portion of the extending portion may be bent so that the surface on the side pressed by the pressing member forms an angle of less than 180 degrees.

[0008] The bent portion may be formed in the pressing portion that is pressed by the pressing member.

[0009] In order to achieve the above-mentioned object, another flexible joint of the present invention is a flexible joint to be installed in a concrete structure, and comprises an expansion / contraction member having an expansion / contraction section that expands and contracts the flexible joint, extension sections extending from both ends of the expansion / contraction section, and bent sections bent from the ends of each of the extension sections, and a pressing member that presses the bent sections against opposing installation surfaces of the concrete structure, wherein the bent sections are formed in an inclined state with respect to the installation surfaces, and the expansion / contraction member is installed in a deformed state by the pressure of the pressing member so as to eliminate the inclination of the bent sections with respect to the installation surfaces. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a flexible joint that can suppress local strain occurring in an expandable member at low cost. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a perspective view showing a part of a flexible joint according to a first embodiment of the present invention. [Figure 2] 1 is a cross-sectional view of a flexible joint according to a first embodiment of the present invention. [Figure 3] 1 is a cross-sectional view of an expansion / contraction member before installation of a flexible joint according to a first embodiment of the present invention. [Figure 4] 1A and 1B are cross-sectional views of a flexible joint according to a first embodiment of the present invention, in which FIG. 1A shows the joint in an installed state, FIG. 1B shows the joint after installation, and FIG. 1C shows the joint in a deformed state due to external pressure. [Figure 5] 1A and 1B are diagrams showing the strain (stress) distribution acting near the pressing portion of the expansion / contraction member, where (a) is a strain distribution diagram of the expansion / contraction member of the flexible joint according to embodiment 1 of the present invention, and (b) is a strain distribution diagram of a conventional expansion / contraction member that does not have a bent portion in the extension portion. [Figure 6] 5A and 5B show a flexible joint according to a second embodiment of the present invention, in which FIG. 5A is a cross-sectional view of the installed flexible joint, and FIG. 5B is a cross-sectional view of the expansion and contraction member of the flexible joint before installation. [Figure 7] 10A and 10B show a flexible joint according to a third embodiment of the present invention, in which FIG. 10A is a cross-sectional view of the installed flexible joint, and FIG. 10B is a cross-sectional view of the expansion and contraction member of the flexible joint before installation. [Figure 8] 10A and 10B show a flexible joint according to a fourth embodiment of the present invention, in which FIG. 10A is a cross-sectional view of the installed flexible joint, and FIG. 10B is a cross-sectional view of the expansion and contraction member of the flexible joint before installation. [Figure 9] FIG. 10 is a cross-sectional view showing the flexible joints of the fifth and sixth embodiments of the present invention that have already been installed. [Figure 10] FIG. 10 is a cross-sectional view of a flexible joint according to a fifth embodiment of the present invention. [Figure 11] FIG. 10 is a cross-sectional view of a flexible joint according to a sixth embodiment of the present invention. [Figure 12] FIG. 10 is a cross-sectional view of a flexible joint according to a seventh embodiment of the present invention before the expansion and contraction member is installed. [Figure 13] The strain generated in the elastic member was calculated by numerical analysis. (a) shows the results for a conventional elastic member, and (b) shows the results for an elastic member with a bent section in the extension section. DETAILED DESCRIPTION OF THE INVENTION

[0012] A flexible joint according to an embodiment of the present invention will be described below with reference to the drawings. The concrete structure 60 shown in FIG. 1 is, for example, a utility tunnel that houses infrastructure facilities such as telephone, electricity, gas, and water. In each drawing showing the first embodiment, a Z-axis perpendicular to the installation surface 60a of the concrete structure 60, and X- and Y-axes parallel to the installation surface 60a of the concrete structure 60 and perpendicular to each other are defined. The Y-axis coincides with the direction in which the joints 61 of the concrete structure 60 extend. The +Z-axis direction is defined as the direction from the surface of the concrete structure 60 toward the cavity of the utility tunnel. The utility tunnel has, for example, a rectangular cross-section and walls facing in different directions. Flexible joints are installed around each wall.

[0013] (Embodiment 1) 1 and 2, the flexible joint 1 according to the first embodiment is provided so as to cover a joint 61 of a concrete structure 60. The flexible joint 1 includes an expansion / contraction member 10, an anchor bolt 30 and a nut 31 driven in the longitudinal direction of the flexible joint 1, and a pressing member 40 for pressing the expansion / contraction member 10 against the concrete structure 60.

[0014] The elastic member 10 has its longitudinal direction in the direction in which the joint portion 61 extends (Y-axis direction), and is installed so as to cover the joint portion 61. The elastic member 10 is made of an elastic material, such as chloroprene rubber. As shown in FIG. 2, the elastic member 10 has an elastic portion 11 with a mountain-shaped cross section that is provided so as to straddle the joint portion 61, and extension portions 13 that extend to both sides from both ends of the elastic portion 11.

[0015] The expansion and contraction section 11 is bent in a curved state so that it can follow the displacement of the concrete structure 60 to which the flexible joint 1 is attached. The expansion and contraction section 11 has a substantially V-shape (mountain-like shape), and the expansion and contraction member 10 expands and contracts by being stretched and bent.

[0016] When the flexible joint 1 is installed on the concrete structure 60, the extension portion 13 extends parallel to the installation surface 60a (surface) of the concrete structure 60. When viewed in the longitudinal direction as shown in FIG. 2, the flexible joint 1 has a configuration that is symmetrical about a center line (not shown) that extends in the up-down direction. Therefore, the following will describe the configuration of the flexible joint 1 on the right side in FIG. 2, and will omit a description of the configuration on the left side. As shown in FIG. 1, the extension portion 13 is a rectangular portion in plan view with its longitudinal direction in the Y-axis direction. The extension portion 13 has a plurality of bolt insertion holes 12a formed therein for inserting anchor bolts 30 in the longitudinal direction. The extension portion 13 has a pressing portion 12 that is pressed by the pressing member 40 and attached to the concrete structure 60, a deformed portion 14 that is adjacent to the expansion / contraction portion 11 side of the pressing portion 12 and is not pressed by the pressing member 40, and an outer edge portion 15 that is adjacent to the opposite side (outside) of the pressing portion 12 from the deformed portion 14 and is not pressed by the pressing member 40. In Figure 2, the boundaries between the deformed portion 14, the pressing portion 12, and the outer edge portion 15 are shown with dashed lines, but these are merely rough indications and are not strictly defined. The pressing member 40 is placed on the +Z side surface of the pressing portion 12. When the nut 31 is tightened onto the anchor bolt 30, the pressing member 40 presses the extension portion 13 against the concrete structure 60.

[0017] The pressing portion 12 is the portion pressed by the pressing member 40 and is the portion directly below the pressing member 40. As shown in FIG. 2, two protrusions 12b that protrude in the -Z direction are formed on the surface of the pressing portion 12 facing the concrete structure 60 (the -Z side surface). The protrusions 12b are arranged in two rows with the anchor bolt 30 in between, and extend in the longitudinal direction (Y-axis direction). The protrusions 12b have a semicircular cross-sectional shape, and their shape and size are constant in the longitudinal direction.

[0018] The deformation portion 14 is interposed between the expansion / contraction portion 11 and the pressing portion 12, connecting them together. The deformation portion 14 deforms together with the expansion / contraction portion 11 when the water pressure of water flowing out from the joint portion 61 acts on the deformation portion 14 or when the concrete structure 60 is displaced.

[0019] The anchor bolts 30 are so-called adhesive anchors, and are fixed by filling holes drilled in the concrete structure 60 with adhesive. The anchor bolts 30 are driven into the concrete structure 60 on both sides of the joint 61 along the longitudinal direction (Y-axis direction).

[0020] The pressing member 40 is a long, rectangular plate member. The pressing member 40 is made of, for example, stainless steel. A bolt insertion hole 40a is formed in the pressing member 40 to insert the anchor bolt 30 in the longitudinal direction. The pressing member 40 is placed on the +Z side surface of the pressing portion 12. The pressing portion 12 is pressed against the concrete structure 60 by tightening the nut 31 screwed onto the anchor bolt 30. In this way, the flexible joint 1 is fixed to the concrete structure 60. The protruding portion 12b protruding from the pressing portion 12 is pressed against the concrete structure 60 and blocks water that has flowed out from the joint portion 61. Note that the installation surface 60a of the concrete structure 60, on which the flexible joint 1 is attached, sandwiching the joint portion 61, is flush. Therefore, the pressing portions 12 provided on both sides of the expansion member 10 are pressed against the concrete structure 60 in a parallel state.

[0021] The flexible joint 1 installed on the concrete structure 60 has been described above with reference to FIGS. 1 and 2. Next, the expansion / contraction member 10 before the flexible joint 1 is installed will be described. Before the expansion / contraction member 10 is installed, the extension portions 13 provided on both sides of the expansion / contraction section 11 have bent portions 13a, as shown in FIG. 3. The bent portion 13a is formed at the inner protrusion 12b of the two protrusions 12b formed on one side of the pressing section 12. Specifically, the bent portion 13a is closer to the expansion / contraction section 11 than the inner protrusion 12b, and is formed near the boundary between the pressing section 12 and the deformation section 14. In the extension portion 13, the central side (inner side) of the bent portion 13a is parallel to each other and faces the installation surface 60a of the concrete structure 60. On the other hand, the distal side (outer side) of the bent portion 13a is not parallel to each other but is formed in an inclined state with respect to the installation surface 60a of the concrete structure 60. Specifically, in the extension 13 provided on the right side in FIG. 3 , the distal end side of the bent portion 13a is formed so as to move away from the installation surface 60a of the concrete structure 60, which is the installation target, as it moves toward the distal end (right side). In other words, the distal end side of the bent portion 13a is formed so as to move in the +Z direction as it moves toward the +X direction. In this manner, in the bent portion 13a of the extension 13, the bending angle θ1 formed by the surface pressed by the pressing member 40 is set to less than 180 degrees. The bending angle θ1 is, for example, 172.5 degrees, but is not limited to this angle. On the other hand, in the extension 13 provided on the left side in FIG. 3 , the distal end side of the bent portion 13a is formed so as to move away from the installation surface 60a of the concrete structure 60, which is the installation target, as it moves toward the distal end (left side). In other words, the distal end side of the bent portion 13a is formed so as to move in the +Z direction as it moves toward the -X direction. The inclination angle θ2 of the portion of the bent portion 13a on the distal end side relative to the installation surface 60a is, for example, 7.5 degrees, but is not limited to this angle.

[0022] A curved portion 14a is formed in a portion continuing from the stretchable portion 11. The curved portion 14a is interposed between the stretchable portion 11 and the deformable portion 14.

[0023] Next, the installation procedure for the flexible joint 1 will be described. First, the anchor bolt 30 is cast into the concrete structure 60. Next, the expansion member 10 and the presser member 40 are passed through the anchor bolt 30 cast into the concrete structure 60. Next, as shown in FIG. 4(a), the nut 31 is tightened to the anchor bolt 30 cast into the concrete structure 60 on one side (the left side in FIG. 4(a)) of the joint 61. As a result, the pressing portion 12 on the left side in the figure is pressed against the concrete structure 60 by the presser member 40, and the tip side of the bent portion 13a is deformed to eliminate the inclination with respect to the installation surface 60a. In other words, the extension portion 13 is deformed to eliminate the bending at the bent portion 13a, and the bending angle θ1 (FIG. 3) at the bent portion 13a approaches 180 degrees. Next, the nut 31 is tightened onto the anchor bolt 30 that has been installed in the concrete structure 60 on the other side (the right side in FIG. 4(b)) of the joint portion 61. As a result, the pressing portion 12 on the right side in the figure is pressed against the concrete structure 60 by the pressing member 40, and the portion on the tip side of the bent portion 13a is deformed to eliminate the inclination with respect to the installation surface 60a. In other words, the extension portion 13 is deformed to eliminate the bending at the bent portion 13a, and the bending angle θ1 (FIG. 3) at the bent portion 13a becomes close to 180 degrees. As a result, the pressing portion 12 is brought into close contact with the installation surface 60, and the installation of the expandable member 10 is completed.

[0024] Suppose water flows out from the joint 61 covered by the flexible joint 1 installed in this manner. The water that flows out from the joint 61 is stopped by the expandable member 10 and the protrusion 12b formed on the expandable member 10. This prevents water from leaking out from the flexible joint 1. The water that leaks out from the joint 61 is collected between the expandable member 10 and the concrete structure 60, and as shown by the arrow in Figure 4(c), water pressure acts on the -Z side surface of the expandable member 10. The expandable member 10 is pushed toward the +Z side, but because it is fixed to the concrete structure 60 by the holding member 40, it expands toward the +Z side to resist the force of the outflowing water.

[0025] As described above in detail regarding the embodiments, the flexible joint 1 according to embodiment 1 of the present invention is a flexible joint 1 provided in a joint portion 61 of a concrete structure 60, and comprises an expansion / contraction section 11 that expands and contracts the flexible joint 1, an extension section 13 that extends from both ends of the expansion / contraction section 11 and has a pressing section 12, an expansion / contraction member 10 that is provided so that the expansion / contraction section 11 straddles the joint portion 61, and pressing members 40 that are arranged on both sides of the joint portion 61 and press the pressing section 12 against the concrete structure 60, and a bent bending portion 13a is formed in the extension portion 13, and the expansion / contraction member 10 is provided in a deformed state so as to eliminate the bending of the bending portion 13a due to the pressure from the pressing member 40.

[0026] With this configuration, for example, if the force of water leaking from the joint portion 61 acts on the expansion member 10, the expansion member 10 will expand and deform toward the +Z side as shown in Figure 4(c). However, since the expansion member 10 is deformed in advance to offset the strain caused by this deformation, it is possible to reduce the local strain caused in the expansion member 10 by external pressure.

[0027] This effect will be explained in detail. External pressure, such as water pressure, does not act directly on the pressing portion 12, but acts on the stretchable portion 11 and the deformable portion 14, which are located inside the pressing portion 12. Therefore, the area around the boundary between the pressing portion 12 and the deformable portion 14 (hereinafter referred to as the boundary portion 53) corresponds to the inner edge portion 40b (FIG. 4(c)) of the pressing member 40, and is prone to large local strain. The strain (stress) that occurs at this boundary portion 53 will be explained below. Note that, because the stretchable member 10 is made of an elastic material such as chloroprene rubber, stress and strain are proportional to each other. Therefore, in FIG. 5, strain and stress are not distinguished from each other and are shown as a single diagram.

[0028] As explained with reference to FIGS. 4(a) and 4(b), when the expandable member 10 is installed, the expandable member 10 is deformed by the pressure of the pressing member 40 so as to eliminate the inclination of the pressing portion 12 relative to the installation surface 60a. This deformation causes a bending moment (negative bending) to act on the boundary portion 53, causing it to be convex upward. In the following explanation of the bending moment, the direction of the surface on the +Z side will be described as the upward direction. This bending moment causes a compressive strain (stress) to act on the lower side (the -Z side, the installation surface 60a side) of the boundary portion 53, and a tensile strain (stress) to act on the upper side, as shown in FIG. 5(a). These strains (stresses) increase in proportion to the distance from the neutral axis, with the neutral axis being 0.

[0029] Next, when external pressure, such as water pressure, acts on the expandable member 10 as shown by the arrows in Figure 4(c), a tensile force and a downwardly convex bending moment (positive bending) act on the boundary 53. As a result, as shown in Figure 5(a), when external pressure is applied, the cross section of the boundary 53 is subjected to a uniform tensile strain (stress), a downward tensile strain (stress) caused by the bending moment (positive bending), and an upward compressive strain (stress) caused by the bending moment (positive bending). Here, for convenience, we assume that the bending moment M1 acting during installation and the bending moment M2 acting during external pressure are equal in absolute value and opposite in sign, but this relationship is not limited to these depending on the external pressure being applied. In this case, the strains (stresses) caused by the two moments cancel each other out, and ultimately, only a uniform tensile strain (stress) acts on the boundary 53.

[0030] On the other hand, in a conventional telescopic member 10 that does not have a bent portion 13a in the extension portion 13, as shown in Figure 5(b), no strain (stress) acts on the boundary portion 53 when the telescopic member 10 is installed. When external pressure such as water pressure acts on the telescopic member 10 as shown by the arrows in Figure 4(c), the boundary portion 53 is subjected to a uniform tensile strain (stress), a tensile strain (stress) on the lower side due to a bending moment (positive bending), and a compressive strain (stress) on the upper side, as in the case described with reference to Figure 5(a). Ultimately, the boundary portion 53 is subjected to the sum of the uniform tensile strain (stress) due to the external pressure and the strain caused by the bending moment.

[0031] When comparing the total strain (stress), the tensile strain (stress) at the lower edge of the boundary portion 53 shown in Figure 5(a) is smaller than the tensile strain (stress) at the lower edge of the boundary portion 53 shown in Figure 5(b). In other words, by deforming the telescopic member 10 in advance, a strain (stress) is applied to the telescopic member that offsets the strain (stress) when a bending moment due to external pressure is applied, so that local strain in the telescopic member 10 that occurs when external pressure is applied can be suppressed. Furthermore, suppressing local strain can be achieved at low cost because it is only necessary to provide a bent portion 13a in the extension portion 13.

[0032] Furthermore, the bent portion 13a of the extending portion 13 is bent so that the surface on the side pressed by the pressing member 40 forms an angle of less than 180 degrees.

[0033] According to this configuration, the pressing member 40 can easily press the pressing portion 12, and the extensible member 10 can easily be deformed in advance.

[0034] The bent portion 13a is formed in the pressing portion 12 that is pressed by the pressing member 40.

[0035] According to this configuration, by directly pressing down the bent portion 13a with the pressing member 40, it is easy to deform the bent portion so that the bending angle approaches 180 degrees and introduce bending stress into the extensible member 10.

[0036] The present invention is not limited to the above-described embodiment, and various modifications and applications are possible.

[0037] (Embodiment 2) Next, a flexible joint 101 according to a second embodiment will be described with reference to Fig. 6. The flexible joint 101 shown in Fig. 6 differs from the flexible joint 1 (Fig. 1) of the above embodiment in that the expansion section 111 of the expansion member 110 has an increased number of folds and is accordion-shaped, a protective cloth 170 is provided to protect the expansion member 110, and a water-stop material 20 is provided between the expansion member 110 and the concrete structure 60. On the other hand, since there are many components in common with the above embodiment, the common components are denoted by the same reference numerals and a description of the common components will be omitted.

[0038] As shown in FIG. 6(a), the expandable member 110 has an accordion-shaped expandable portion 111 folded back multiple times and an extending portion 113. The expandable portion 111 has two arc portions convex in the +Z-axis direction and one arc portion convex in the -Z-axis direction. Because the expandable member 110 has the accordion-shaped expandable portion 111 folded back multiple times, it has a larger amount of expansion and contraction in the X-axis direction than the expandable member 10 of the first embodiment (FIG. 2). As shown in FIG. 6(b), the extending portion 113 has a pressing portion 112 that is pressed by the pressing member 40 and attached to the concrete structure 60, and a deformed portion 114 that is adjacent to the expanding portion 111 side of the pressing portion 112 and is not pressed by the pressing member 40, but has almost no outer edge portion 15 (FIG. 2). As shown in FIG. 6(a), the pressing member 40 is placed on the +Z side surface of the pressing portion 112, and a nut 31 is tightened to the anchor bolt 30. As a result, the pressing member 40 presses the extension portion 113 toward the concrete structure 60 .

[0039] The protective cloth 170 covers and protects the elastic member 110. Both edge portions 170a of the protective cloth 170 in the X-axis direction are sandwiched between the presser member 40 and the elastic member 110, thereby covering the elastic member 110. The protective cloth 170 is provided with folding portions 171 so as to accommodate the expansion and contraction of the elastic member 110.

[0040] The water stopping material 20 is a long rectangular rubber material, and is made of, for example, butyl rubber. The water stopping material 20 is arranged in contact with the -Z side surface of the pressing part 112. The water stopping materials 20 are arranged in two rows with the anchor bolt 30 sandwiched between them. That is, the water stopping materials 20 are arranged with their longitudinal direction facing the Y axis and with gaps in the X axis direction for the anchor bolt 30 to pass through. The water stopping material 20 is provided between the concrete structure 60 and the pressing part 112.

[0041] As shown in FIG. 6(b), the extension portion 113 of the expandable member 110 before installation in the second embodiment also has a bent portion 113a. The bent portion 113a is located outside the boundary between the pressing portion 112 and the deforming portion 114 and is formed at the edge of the boundary. The distal end of the pressing portion 112 from the bent portion 113a is not parallel to each other but is inclined toward the installation surface 60a of the concrete structure 60 as it approaches the distal end. When the expandable member 110 is installed, the extension portion 113 is deformed by the pressure of the pressing member 40 to eliminate the bending at the bent portion 113a. The strain caused by this deformation offsets the strain caused by external pressure, such as the water pressure of water leaking from the joint portion 61. Therefore, local strain of the expandable member 110 caused by external pressure can be suppressed. This effect is similar to that of the first embodiment.

[0042] Furthermore, a water-stopping material 20 is interposed between the concrete structure 60 and the pressing portion 112. Water leaking from the joint portion 61 can be stopped by the elastic member 110 and the water-stopping material 20 formed between the elastic member 110 and the concrete structure 60, thereby preventing water from leaking out from the flexible joint 101.

[0043] (Embodiment 3) Next, a flexible joint 201 according to a third embodiment will be described with reference to Fig. 7. In this embodiment, the anchor bolts 30 are not passed through the expansion and contraction members 210, and the expansion and contraction members 210 are pressed against the concrete structure 60 by the pressing members 240 fastened via the anchor bolts 30. In this way, the method of attaching the expansion and contraction members 210 differs from the above-described embodiments.

[0044] As shown in Figure 7(a), the flexible joint 201 includes an expandable member 210, a water-stopping material 220 interposed between the expandable member 210 and the surface of the concrete structure 60, anchor bolts 30 installed in line along the longitudinal direction of the flexible joint 201, a pressing member 240 for pressing the expandable member 210 against the concrete structure 60, and a fixing member 270 for fixing the pressing member 240.

[0045] The fixing member 270 has a pair of pressing arms 271 spaced apart in the Y-axis direction, and an intermediate plate-shaped portion 272 connecting the pair of pressing arms 271. A bolt hole (not shown) for the anchor bolt 30 is formed in the intermediate plate-shaped portion 272. The fixing member 270 is made of, for example, stainless steel.

[0046] The pressing member 240 has, for example, a cross section of a lip groove shape that is roughly U-shaped and opens upward, and the cross-sectional shape and size are constant in the longitudinal direction (Y-axis direction). The pressing member 240 is provided on the pressing portion 212 so that the placement surface 240b, which faces the surface on which the opening 240a is formed, comes into contact with the pressing portion 212.

[0047] 7(b), the expandable member 210 includes an accordion-shaped expandable portion 211 that is folded back multiple times, and extending portions 213 provided on both sides of the expandable portion 211. The extending portion 213 includes a pressing portion 212 that is pressed against the holding member 240 and attached to the concrete structure 60, a deformable portion 214 that is adjacent to the expandable portion 211 side of the pressing portion 212 and is not pressed by the holding member 240, and an outer edge portion 215 that is adjacent to the opposite side (outside) of the deformable portion 214 of the pressing portion 212 and is not pressed by the holding member 240. A protruding edge portion 215a that protrudes toward the +Z side is formed at the end of the outer edge portion 215.

[0048] The pressing member 240 is installed on the pressing portion 212. By placing a pair of pressing arms 271 on the pressing member 240 and tightening the nut 31 of the anchor bolt 30, the fixing member 270 presses the pressing portion 212 via the pressing member 240.

[0049] 7(b), in the expandable member 210 before installation according to the third embodiment, the extending portion 213 also has a bent portion 213a. The bent portion 213a is located outside the boundary between the pressing portion 212 and the deforming portion 214, and is formed at the edge of said boundary. The portions of the pressing portion 212 further toward the tip than the bent portion 213a are not parallel to each other, but are inclined away from the installation surface 60a of the concrete structure 60 as they approach the tip.

[0050] When the expandable member 210 is installed, the extension portion 213 is deformed by the pressure of the pressing member 240 so as to eliminate the bending at the bent portion 213a. The strain caused by such deformation offsets the strain caused when the expandable member 210 is subjected to external pressure, such as the water pressure of water leaking from the joint portion 61. Therefore, it is possible to suppress the local strain of the expandable member 210 that occurs when external pressure is applied. This effect is the same as that of the first embodiment described above.

[0051] (Fourth embodiment) Next, a flexible joint 301 according to a fourth embodiment will be described with reference to Fig. 8. The flexible joint 301 differs from the flexible joint 1 of the first embodiment shown in Fig. 2 in the method of fixing the expansion member 310. That is, no anchor bolts 30 are passed through the expansion member 310 of the flexible joint 301, and the expansion member 310 is pressed and fixed against the concrete structure 60 by a presser member 340 tightened by the anchor bolts 30.

[0052] 8(a), the expandable member 310 includes a substantially V-shaped expandable portion 311 and extending portions 313 provided on both sides of the expandable portion 311. The extending portions 313 include a pressing portion 312 that is pressed against the holding member 340 and attached to the concrete structure 60, and a deformable portion 314 that is adjacent to the expanding portion 311 side of the pressing portion 312 and is not pressed by the holding member 340.

[0053] The pressing portions 312 are convex portions with rectangular cross sections that rise in the +Z direction from both ends of the expandable member 310. The pressing portions 312 extend in the longitudinal direction (Y-axis direction), and the cross-sectional shape and size are constant in the longitudinal direction.

[0054] The pressing member 340 has a flat portion 341 that is fastened by the anchor bolt 30 on the outside of the expansion and contraction member 310, and a grooved portion 342 formed on the edge of the flat portion 341. A bolt hole (not shown) through which the anchor bolt 30 passes is formed in the flat portion 341. The grooved portion 342 is a channel-shaped portion with an opening at the bottom, into which the pressing portion 312 is fitted. With the grooved portion 342 fitted into the pressing portion 312, the nut 31 is tightened onto the anchor bolt 30. In this way, the pressing member 340 presses the expansion and contraction member 310 against the concrete structure 60, fixing it in place.

[0055] In the expandable member 310 before installation according to the fourth embodiment, as shown in FIG. 8(b), the pressing portions 312 provided on both sides of the expandable portion 311 are not parallel to each other, but are inclined so as to move away from each other toward the tip with respect to the installation surface 60a of the concrete structure 60. The inclination of the pressing portions 312 is formed by making the intersection angle θ3 between the protruding direction of the pressing portions 312 and the direction of the deformation portion 314 extending parallel to the installation surface 60a (X direction) smaller than 90 degrees. In other words, the protruding directions of the pressing portions 312 formed at both ends of the expandable member 310 are not parallel, and the pressing portions 312 are formed so as to lean toward each other toward the expandable portion 311 (toward the center).

[0056] When the expandable member 310 is installed, the grooved portion 342 is fitted into the pressing portion 312 and pressed against the concrete structure 60. As a result, the expandable member 310 is bent and deformed so that the protruding direction of the pressing portion 312 becomes perpendicular to the deforming portion 314. That is, the expandable member 310 deforms to eliminate the inclination of the pressing portion 312 with respect to the installation surface 60a. As a result, an upwardly convex bending moment (negative bending) acts on the boundary portion 353 between the deforming portion 314 and the pressing portion 312 shown in FIG. 8(a), similar to the boundary portion 53 (FIG. 4(b)) in the first embodiment. The strain caused by such deformation offsets the strain caused by external pressure, such as the water pressure of water leaking from the joint portion 61. Therefore, local strain of the expandable member 310 caused by external pressure can be suppressed. This effect is similar to that of the first embodiment.

[0057] (Embodiment 5) Next, a flexible joint 401 according to a fifth embodiment will be described with reference to Figures 9 and 10. In each figure showing the fifth embodiment, the direction in which the installation surface (opposing surface) 63a of the concrete structure 63 and the installation surface (opposing surface) 64a of the concrete structure 64 face each other is defined as the X-axis direction, the direction in which the flexible joint 401 extends and is perpendicular to the X-axis direction is defined as the Y-axis direction, and the direction perpendicular to the X-axis and Y-axis directions is defined as the Z-axis direction. Also, Figure 10 illustrates the flexible joint 401 in different states on the left and right, with the left side showing the state installed on the concrete structure 64 and the right side showing the state before installation.

[0058] The flexible joint 401 is installed, for example, in a state of bridging between an installation surface 63a of a concrete structure 63 and an installation surface 64a of a concrete structure 64 that are installed with a gap therebetween.

[0059] The flexible joint 401 has a pressing member 440 attached to the installation surface 63a and the installation surface 64a, and an expandable member 410 attached to the concrete structures 63, 64 by the pressing member 440. Note that the two pressing members 440 shown in Fig. 9 have a symmetrical configuration, so the following will explain the configuration of the pressing member 440 on the right side.

[0060] The holding member 440 has a first holding portion 441 and a second holding portion 442 attached to an end of the first holding portion 441 and intersecting with the first holding portion 441. In the present embodiment, the first holding portion 441 and the second holding portion 442 are perpendicular to each other, but the angle at which they intersect is not particularly limited. The first holding portion 441 is formed with an anchor bolt insertion hole (not shown) through which the anchor bolt 30 is inserted.

[0061] The elastic member 410 has an elastic portion 411 having an approximately U-shaped cross section, extension portions 412 extending left and right from both ends of the elastic portion 411, and bent portions (pressing portions) 413 extending in the +Z direction from each tip of the extension portions 412 and pressed by the pressing member 440.

[0062] The bent portion 413 on the right side in Fig. 9 is pressed against the installation surface 63a by the first pressing portion 441 on the right side in the figure. Moreover, the bent portion 413 on the left side in Fig. 9 is pressed against the installation surface 64a by the first pressing portion 441 on the left side in the figure. In this way, the expandable member 410 is fixed in the gap between the concrete structures 63, 64 while bridging between the installation surfaces 63a and 64a.

[0063] Additionally, the second pressing portion 442 comes into contact with the surface on the +Z side of the extending portion 412. As shown by arrow Y1 in Fig. 9, for example, when the expandable member 410 is pressed by water pressure from the -Z side in the +Z direction, the second pressing portion 442 presses a part of the extending portion 412 so that the entire extending portion 412 does not deform in the +Z direction.

[0064] Next, the shape of the expandable member 410 before installation will be described. As shown on the right side of FIG. 10, the bent portion 413 of the expandable member 410 is formed in a tilted state with respect to the installation surface 63a of the concrete structure 63. Specifically, the bent portion 413 is tilted so that it moves away from the installation surface 63a of the concrete structure 63, on which it is to be installed, as it approaches the tip (upper side). This is also true for the bent portion 413 on the left side of FIG. 10. That is, the bent portion 413 is formed in a tilted state leaning toward the expandable portion 411 (toward the center). A curved portion 412a is formed in the portion continuing from the expandable portion 411. The curved portion 412a is interposed between the expandable portion 411 and the extending portion 412, and tilts the extending portion 412 continuing from the expandable portion 411 toward the +Z side with respect to the left-right direction (X-axis). Therefore, the bent portion 413 connected perpendicularly to the extending portion 412 is tilted with respect to the installation surface 63a.

[0065] When installing the telescopic member 410, the pressing member 440 is tightened with the anchor bolt 30, so that the first pressing portion 441 presses the bent portion 413 against the installation surfaces 63a, 64a, and the second pressing portion 442 presses the surface of the extending portion 412 facing the +Z side. As a result, as shown on the left side of Figure 10, the pressure of the pressing member 440 causes the telescopic member 410 to deform so as to eliminate the inclination of the bent portion 413 relative to the installation surfaces 63a, 64a. This brings the bent portion 413 into close contact with the installation surfaces 63a, 64a, completing the installation of the telescopic member 410.

[0066] Suppose that water pressure acts from below (-Z side) to above (+Z direction) on a flexible joint 401 having such an expandable member 410, as shown by arrow Y1 in Fig. 10. The expandable member 410 expands toward the +Z side as shown by the two-dot chain line in Fig. 10, resisting the water pressure. At this time, the expanded expandable member 410 hits the inner edge portion 442a of the second pressing portion 442, forming a bent portion 414 in the extension portion 412 that bends at the point where it hits the inner edge portion 442a.

[0067] As described above in detail regarding the embodiments, the flexible joint 1 according to the fifth embodiment of the present invention is a flexible joint 401 provided on concrete structures 63, 64, and comprises an expansion / contraction member 410 having an expansion / contraction section 411 that expands and contracts the flexible joint 401, extension sections 412 extending from both ends of the expansion / contraction section 411, and bent sections 413 bent from the ends of each extension section 412, and a pressing member 440 that presses the bent sections 413 against the opposing installation surfaces 63a, 64a of the concrete structures 63, 64, the bent sections 413 being formed in a tilted state relative to the installation surfaces 63a, 64a, and the expansion / contraction member 410 is provided in a deformed state due to the pressure from the pressing member 440 so as to eliminate the tilt of the bent sections 413 relative to the installation surfaces 63a, 64a.

[0068] According to this configuration, by deforming the expandable member 410 by pressing the pressing member 440, a bending moment (negative bending) that causes the extending portion 412 to be convex upward in the figure can be applied. Meanwhile, in FIG. 10, water pressure acting from below to above, as indicated by arrow Y1, forms a bent portion 414, and a bending moment (positive bending) that causes the extending portion 412 to be convex downward is applied to the bent portion 414. In this way, the positive and negative bending moments can be reversed when the expandable member 410 is installed and when water pressure acts on the expandable member 410. In other words, a strain that offsets the strain that occurs when the expandable member is subjected to water pressure can be applied to the extending portion 412 in advance, and similar to the first embodiment, local strain in the expandable member caused by external pressure can be suppressed.

[0069] (Sixth embodiment) Next, a flexible joint 401 according to a sixth embodiment will be described with reference to Figures 9 and 11. The flexible joint 401 of this embodiment differs from the flexible joint 401 of the fifth embodiment only in the inclination direction of the bent portion 413, and the other configurations are the same. Therefore, the same reference numerals as those of the flexible joint 401 of the fifth embodiment are used for the reference numerals assigned to the respective components. Also, in Figure 11, as in Figure 10, the flexible joint 401 is shown in different states on the left and right, with the left side showing the state installed on the concrete structure 64 and the right side showing the state before installation.

[0070] As shown in Figure 9, the state in which the flexible joint 401 of embodiment 6 is installed in concrete structures 63, 64 is the same as in embodiment 5. In embodiment 5, the inclination direction of the bent portion 413 is determined on the assumption that water pressure acts on the expandable member 410 from below to above, as shown by arrow Y1 in Figure 9. On the other hand, in this embodiment, the inclination direction of the bent portion 413 is determined on the assumption that water pressure acts on the expandable member 410 from above to below, as shown by arrow Y2 in Figure 9.

[0071] Next, the shape of the expandable member 410 before installation will be described with reference to FIG. 11. As shown on the right side of FIG. 11, the bent portion 413 of the expandable member 410 is formed in a state inclined with respect to the installation surface 63a of the concrete structure 63. Specifically, the bent portion 413 is inclined so that it approaches the installation surface 63a of the concrete structure 63, on which it is to be installed, as it approaches the tip side (upper side). This is also true for the bent portion 413 on the left side in FIG. 11. That is, the bent portion 413 is formed in a state inclined and leaning toward the outside of the expandable member 410. This inclination of the bent portion 413 is formed by making the intersection angle θ4 between the bent portion 413 and the extending portion 412 greater than 90 degrees.

[0072] When installing the telescopic member 410, the pressing member 440 is tightened with the anchor bolt 30, so that the first pressing portion 441 presses the bent portion 413 against the installation surfaces 63a, 64a, and the second pressing portion 442 presses the surface of the extending portion 412 facing the +Z side. As a result, as shown on the left side of Figure 11, the pressure of the pressing member 440 causes the telescopic member 410 to deform so as to eliminate the inclination of the bent portion 413 relative to the installation surfaces 63a, 64a. This brings the bent portion 413 into close contact with the installation surfaces 63a, 64a, completing the installation of the telescopic member 410.

[0073] Suppose that water pressure acts from above (+Z side) downward (-Z direction) on flexible joint 401 having such an expandable member 410, as shown by arrow Y2 in Figure 11. The expandable member 410 expands toward the -Z side as shown by the two-dot chain line in Figure 11 to resist the water pressure. At this time, local strain is likely to occur at boundary portion 415, which is the boundary between bent portion 413 and extended portion 412, due to the action of water pressure.

[0074] According to the above configuration, the pressing force of the pressing member 440 causes the expandable member 410 to deform so as to eliminate the inclination of the bent portion 413 relative to the installation surfaces 63a, 64a. As a result, a downwardly convex bending moment (positive bending) acts on the boundary portion 415, which is the boundary between the bent portion 413 and the extending portion 412. Meanwhile, in FIG. 11 , a bending moment (negative bending) acts on the boundary portion 415 due to water pressure acting from above downward, as indicated by arrow Y2. In this way, the positive and negative bending moments can be reversed when the expandable member 410 is installed and when water pressure acts on the expandable member 410. In other words, a strain that offsets the strain that occurs when the expandable member 410 is subjected to water pressure can be applied to the boundary portion 415 in advance, and similar to the first embodiment, local strain of the expandable member caused by external pressure can be suppressed.

[0075] (Embodiment 7) Next, a seventh embodiment will be described. In the above-described first to third embodiments, for example, as shown in FIG. 3, the extension portion 13 has a bent portion 13a formed therein, and the central side (inner side) of the bent portion 13a faces the installation surface 60a of the concrete structure 60, while the distal side (outer side) of the bent portion 13a is inclined relative to the installation surface 60a of the concrete structure 60. However, as shown in FIG. 12, the effects of the present invention can be obtained as long as the bending angle θ5 of the surface pressed by the pressing member is less than 180 degrees. The directions of extension to both sides of the bent portion 513a are arbitrary. For example, as shown in FIG. 12, the distal side (outer side) of the extension portion 513 is parallel to each other and faces the installation surface 60a of the concrete structure 60. On the other hand, the central side (inner side) of the extension portion 513 is not parallel to each other but is inclined relative to the installation surface 60a of the concrete structure 60. Specifically, the portion closer to the center (inner side) than the bent portion 513a is formed so as to become more distant from the installation surface 60a of the concrete structure 60 on which the bent portion 513a is to be installed as it approaches the center.

[0076] As shown in FIG. 12, the extension portion 513 of the expandable member 510 before installation according to the seventh embodiment also has a bent portion 513a. When the expandable member 510 is installed, the pressure applied by the pressing member 40 causes the member to deform so as to eliminate the bending at the bent portion 513a, i.e., so that the bending angle θ5 approaches 180 degrees. After the bending is eliminated, the member returns to the state shown in FIG. 2. The strain caused by such deformation offsets the strain caused when the member is subjected to external pressure, such as the pressure of water leaking from the joint portion 61. Therefore, it is possible to suppress local strain in the expandable member 510 when external pressure is applied. This effect is the same as that of the first to third embodiments described above.

[0077] 13(a) and 13(b), numerical analysis using the finite element method was used to calculate the strain that occurs in a conventional telescopic member 610A that does not have a bent portion in the extension portion 613A (FIG. 13(a)), and the strain that occurs in a telescopic member 610 that has a bent portion in the extension portion 613A (FIG. 13(b)), when the telescopic members 610A, 610 are subjected to a force in the Z-axis direction (upward in the figure). Note that the lighter the color in the figure, the greater the strain that occurs.

[0078] In both cases, the amount of strain increased around the part that came into contact with the inner edge 40b of the pressing member 40, and the maximum strain of the conventional elastic member 610A without a bent portion was 0.631 (Fig. 13(a)), while the maximum strain of the elastic member 610 with a bent portion was 0.550. In this way, it was confirmed that the maximum strain generated in the elastic member can be suppressed by forming a bent portion in the extension portion 613 that is bent in an appropriate direction based on the direction in which an external force such as water pressure acts.

[0079] The present invention is not limited to the above-described embodiment, and various modifications and applications are possible. The bent portion pressed by the pressing member has been described as being bent in a dogleg shape, but it may also be bent in a curved shape. The bent portion refers to a portion bent in various ways.

[0080] Furthermore, as explained with reference to Figure 3, the bending angle θ1 of the surface pressed by the pressing member 40 is set to less than 180 degrees, but if the anticipated water pressure or other external pressure acts from the opposite direction, the bending angle θ1 can be made greater than 180 degrees, i.e., the angle of the surface on the concrete structure 60 side can be made less than 180 degrees.

[0081] Although the bent portion is described as being formed in the pressing portion, it may be formed at a location away from the pressing portion as long as it is near the boundary between the pressing portion and the deformation portion. Alternatively, the pressing portion may be tilted so as to gradually move away from the concrete structure at the curved portion 14a in Fig. 3, and the tilt of the pressing portion may be eliminated by pressing it down with a pressing member, thereby introducing bending stress.

[0082] Although the flexible joints described above have been applied to utility tunnels, they can also be used in a variety of concrete structures, such as various water supply and treatment facilities, subways, tunnels, underground passages, and tunnel segments.

[0083] Furthermore, although the material of the elastic member has been described as chloroprene rubber, it may be other rubber materials or may be appropriately selected from among elastic materials.

[0084] The features described in the above-described embodiments and modifications can be combined in any manner unless they are inconsistent. [Explanation of symbols]

[0085] 1...flexible joint, 10...expandable member, 11...expandable portion, 12...pressure portion, 12a...bolt insertion hole, 12b...protruding portion, 13...extending portion, 13a...bent portion, 14...deformed portion, 14a...curved portion, 15...outer edge portion, 20...waterstop material, 30...anchor bolt, 31...nut, 40...pressing member, 40a...bolt insertion hole, 40b...inner edge portion, 53...boundary portion, 60...concrete structure, 60a...installation surface, 61...joint portion, 63, 64...concrete Structure, 63a, 64a... installation surface, 101... flexible joint, 110... elastic member, 111... elastic portion, 112... pressing portion, 113... extension portion, 113a... bending portion, 114... deformation portion, 114a... curved portion, 170... protective cloth, 170a... edge portion, 171... folding portion, 201... flexible joint, 210... elastic member, 211... elastic portion, 212... pressing portion, 213... extension portion, 213a... bending portion, 214... deformation portion, 214a... bending portion, 215... outer Edge portion, 215a... protruding edge portion, 220... water stop material, 240... pressing member, 240a... opening, 240b... placing surface, 270... fixing member, 271... pressing arm, 272... intermediate plate-shaped portion, 301... flexible joint, 310... elastic member, 311... elastic portion, 312... pressing portion, 313... extension portion, 314... deformation portion, 340... pressing member, 341... flat plate-shaped portion, 342... groove-shaped portion, 353... boundary portion, 401... flexible joint, 410... elastic member, 411... elastic portion, 412...extension portion, 412a...curved portion, 413...bent portion, 414...bent portion, 415...boundary portion, 440...pressure member, 441...first press portion, 442...second press portion, 442a...inner edge portion, 510...elastic member, 511...elastic portion, 512...pressure portion, 513...extension portion, 513a...bent portion, 514...deformed portion, 515...outer edge portion, θ1, θ5...bending angle, θ2...inclination angle, θ3, θ4...intersection angle, M1, M2...bending moment

Claims

1. A flexible joint provided at a joint portion of a concrete structure, An expansion member having an expansion section that expands and contracts the flexible joint, and an extension section that extends from both ends of the expansion section and has a pressing section, and the expansion section is provided so as to straddle the joint section; and pressing members arranged on both sides of the joint portion and pressing the pressing portion against the concrete structure, The extension portion has a bent portion formed therein, The elastic member is provided in a deformed state so as to eliminate the bending of the bent portion by being pressed by the pressing member. Flexible joints.

2. The bent portion of the extension portion is bent so that the surface on the side pressed by the pressing member forms an angle of less than 180 degrees.

10. The flexible joint of claim 1.

3. the bent portion is formed in the pressing portion that is pressed by the pressing member. A flexible joint according to claim 1 or 2.

4. A flexible joint provided in a concrete structure, an elastic member having an elastic section that expands and contracts the flexible joint, extension sections extending from both ends of the elastic section, and bent sections bent from the ends of each of the extension sections; and pressing members that press the bent portion on opposing installation surfaces of the concrete structure, The bent portion is formed in a state inclined with respect to the installation surface, The elastic member is provided in a deformed state by being pressed by the pressing member so as to eliminate the inclination of the bent portion with respect to the installation surface. Flexible joints.

Images