Concrete member, casting method thereof, and segment

Abstract

To provide a concrete member having high compressive strength and high strength even under conditions where high compressive force is applied.SOLUTION: A segment 2B comprises a high-strength concrete section 15 made of concrete with a reinforcing bar cage 16 inside, and precast ultra-high-strength concrete sections 14 arranged on both sides of the high-strength concrete section 15, each with a joint surface 7, and having a higher strength than the high-strength concrete section 15 and with holes H formed on an inner surface 14 facing the high-strength concrete section 15. Main reinforcing bars 18 of the reinforcing bar cage 16 are inserted and fixed into the holes H of the ultra-high-strength concrete section 14.SELECTED DRAWING: Figure 16

Description

[Technical Field]

[0001] The present invention relates to concrete members and segments that constitute the cylindrical walls of shield tunnels, including road tunnels buried at great depths underground, and that can ensure strength even when subjected to large external forces such as earth pressure, as well as a method for pouring such concrete members and segments. [Background technology]

[0002] Generally, in shield tunnels and other structures built at great depths, the external forces acting on the segments that make up the tunnel wall are large due to the loads of earth pressure, groundwater pressure, and buildings. This increases the compressive stress applied to the segment bodies and joints. However, the joints connecting adjacent segments are tension members and cannot guarantee compressive force. Therefore, if RC segments are used, they must be thick enough to withstand external forces, which increases the outer diameter of the tunnel, making it uneconomical and costly.

[0003] As a segment that can withstand such external forces while maintaining a reduced thickness, for example, a composite segment has been proposed, as described in Patent Document 1. In this composite segment, a roughly H-shaped main steel member, consisting of vertically arranged flat steel plates connected by beams, is embedded in concrete between compression transmission members exposed on the opposing joint surfaces. By adjusting the compressive force by placing a wedge between the compression transmission member and the main steel member, the compressive force applied to the opposing joint surface due to external force can be dispersed from the compression transmission member to the main steel member, preventing excessive compressive force from being applied to the segments and preventing the joint surface from collapsing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5285933 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the composite segment described in Patent Document 1 mentioned above, wedge materials are driven between the compression transmission material and the main steel material from opposite directions to set a compressive force that counteracts the external force, making it difficult to adjust the compressive force using the wedge materials.

[0006] The present invention has been made in consideration of such problems, and aims to provide a concrete member with high compressive strength and high compressive resistance even under conditions where high compressive forces act, such as deep underground, as well as a method for pouring the same and segments. Another object of the present invention is to provide a concrete member, a method for placing the same, and a segment that can be reinforced even near the end faces where no compression-resistant members exist. [Means for solving the problem]

[0007] The concrete member of the present invention is a concrete member (2B) having opposing end faces (7), and comprises a high-strength concrete section (15) made of concrete with a reinforcing bar cage (16) inside, and precast ultra-high-strength concrete sections (14) arranged on both sides of the high-strength concrete section, each having the end faces, and having higher strength than the high-strength concrete section, wherein holes (H) are formed in the surface (14a) opposite the end faces, and the reinforcing bars (18) of the reinforcing bar cage are inserted and fixed in the holes.

[0008] The concrete member of the present invention has ultra-high-strength concrete sections at both ends, so even if a large load is applied when the ends of the concrete members are abutted, the ultra-high-strength concrete sections can absorb the load and transmit it to the high-strength concrete section and the reinforcing bar cage, thereby improving compression resistance without increasing the thickness. Furthermore, the ultra-high-strength concrete sections may or may not be connected to the reinforcing bar cage inside the high-strength concrete sections.

[0009] It is also preferable that the ultra-high strength concrete portion has a higher cement blending ratio than the high strength concrete portion. By using a higher cement mix ratio in the ultra-high-strength concrete section than in the high-strength concrete section, a stronger concrete member is obtained, which has high compressive load resistance even when assembled with the ends abutting. Moreover, no additional rebar or compression steel is required.

[0010] The segment of the present invention is a circular arc-shaped segment (2B) that is connected in multiple places at concrete joint surfaces (7) and main girder surfaces (6) to construct a cylindrical wall (3), and comprises a high-strength concrete section (15) with a reinforcing bar cage (16) inside, and precast ultra-high-strength concrete sections (14) that are connected to both sides of the high-strength concrete section and have higher strength than the high-strength concrete section and have holes formed on their surfaces (14a) facing the high-strength concrete section, and the reinforcing bars of the reinforcing bar cage are inserted and fixed into the holes of the ultra-high-strength concrete section.

[0011] According to the segments of the present invention, even when the segments are installed and assembled at great depths, the ultra-high strength concrete sections provide high compressive resistance to loads such as earth pressure, thereby reinforcing strength.Furthermore, since no additional reinforcing bars or compression steel are required, the compressive resistance can be improved without increasing the thickness of the segments.

[0012] The method for pouring a concrete member of the present invention is a method for pouring a concrete member (2B) having opposing end faces (7), and comprises the steps of: positioning and installing precast ultra-high strength concrete (14) having the end faces and having holes (H) formed in a surface (14a) opposite the end faces within a formwork (25) so that the surfaces with the holes face each other; arranging a reinforcing bar cage (16) between the pieces of ultra-high strength concrete within the formwork and inserting reinforcing bars (18) of the reinforcing bar cage into the holes formed in the ultra-high strength concrete; and pouring concrete (C) into the space sandwiched between the ultra-high strength concrete within the formwork, thereby pouring high-strength concrete (15) having a strength lower than that of the ultra-high strength concrete. [Effects of the Invention]

[0013] In the concrete members and segments of the present invention, the end faces are made of ultra-high-strength concrete, so they can be reinforced even when a large compressive force is applied to the end faces. Moreover, even when a large compressive force is applied to the contact surface between the end faces, the load can be transmitted between the ultra-high-strength concrete portion and the reinforcing bar cage inside the high-strength concrete portion. Furthermore, no additional reinforcing bars or compression steel are required, and the ultra-high strength concrete section and the high strength concrete section are integrated, so the strength and compressive resistance can be increased without increasing the thickness of the concrete members and segments.

[0014] The method for casting concrete members according to the present invention makes it possible to produce concrete members made of ultra-high-strength concrete and high-strength concrete, each with different strengths, using a single formwork. Furthermore, the end faces, which are subject to large compressive forces, can be made ultra-high strength, resulting in high compressive strength. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is an explanatory diagram of a tunnel installed in a deep depth section according to an embodiment of the present invention. FIG. [Figure 2] FIG. 2 is a perspective view of a segment of the tunnel shown in FIG. 1. [Figure 3] FIG. 2 is a front view showing the joint surface of the segment. [Figure 4] FIG. 4 is a cross-sectional view of the segment shown in FIG. 3 taken along line AA. [Figure 5] 4 is a cross-sectional view of the segment shown in FIG. 3 along the line BB. [Figure 6] 4 is a cross-sectional view of the segment shown in FIG. 3 taken along line CC. [Figure 7] FIG. 4 is a cross-sectional view of the segment shown in FIG. 3 taken along the line DD. [Figure 8] FIG. 5 is a cross-sectional view taken along the line EE in FIG. [Figure 9] (a), (b), and (c) are diagrams illustrating the manufacturing process of the segment. [Figure 10] FIG. 10 is a perspective view of a segment according to a second embodiment. [Figure 11] FIG. 5 is a cross-sectional view similar to FIG. 4 of a segment according to a second embodiment. [Figure 12] FIG. 7 is a cross-sectional view similar to FIG. 6 of a segment according to a second embodiment. [Figure 13] (a), (b), and (c) are diagrams illustrating the manufacturing process of the segment. [Figure 14] FIG. 10 is a perspective view of a segment according to a third embodiment. [Figure 15] FIG. 10 is a perspective view showing an ultra-high strength concrete portion in a third embodiment. [Figure 16] FIG. 5 is a cross-sectional view similar to FIG. 4 of a segment according to a third embodiment. [Figure 17] FIG. 7 is a cross-sectional view similar to FIG. 6 of a segment according to a third embodiment. [Figure 18] (a), (b), and (c) are diagrams illustrating the manufacturing process of the segment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, a segment applicable to a deep depth section according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0017] First Embodiment Figures 1 to 9 show segments 2 used in a tunnel 1 installed in a deep section according to a first embodiment of the present invention. The tunnel 1 shown in Figure 1 is installed at a depth of, for example, 70 m or more from the ground, and a high-rise building B has been constructed above ground. The tunnel 1 has a cylindrical wall formed by axially connecting segment rings 3, each of which is made up of segments 2 according to the embodiment of the present invention shown in Figures 2 to 8 connected circumferentially.

[0018] Tunnel 1, which is buried underground, is affected by groundwater pressure and the load of buildings in addition to the influence of earth pressure. In the deep section, earth pressure is applied from the ground surface to a depth of, for example, 70 m or more. Specifically, top vertical earth pressure and bottom vertical earth pressure are applied from the top and bottom of tunnel 1, and horizontal earth pressure is applied from the sides. In addition, the load of the groundwater level flowing underground, and the vertical load and lateral pressure of high-rise building B installed above ground are also applied. These loads are applied as compressive loads to the joint surfaces 7 that connect the segments 2 of the segment ring 3 of the tunnel 1. Each segment 2 is required to have a structure that can withstand these compressive loads.

[0019] 2 and 3 is an RC segment. This segment 2 is reinforced by disposing a reinforcing bar cage 16 (described later) inside the segment body made of concrete. The side surfaces of the segment 2 are generally rectangular and include a pair of main girder surfaces 6 curved in a generally arc-like shape within the plane, and a pair of rectangular joint surfaces 7. The segment 2 is generally rectangular in shape overall and curved in a circular arc-like shape. The outer peripheral surface 8 and inner peripheral surface 9 of segment 2 are each curved surfaces of concrete C. The main girder surface 6 and joint surface 7 of segment 2 are also surfaces of concrete C. Joint sections 11 consisting of male joints and joint sections 11 consisting of female joints are installed at predetermined intervals on the main girder surfaces 6 on both sides. Two sets of M hardware 12 as male joints and two sets of F hardware 13 as female joints are attached to the joint surfaces 7 on both sides, for example. Note that the number of male and female joints on the joint surface 7 may be one set.

[0020] The segments 2 have opposing joint surfaces 7 at both ends, which are made of ultra-high strength concrete sections 14, and the long section between them is made of high strength concrete sections 15. In addition, a coarse mesh wire netting 17 is installed as a partition at the boundary between the ultra-high strength concrete sections 14 and the high strength concrete sections 15. The ultra-high strength concrete section 14 has a higher cement mix ratio than the high strength concrete section 15, and is set to be stronger. The design standard strength for the ultra-high strength concrete section 14 is, for example, 80 N / mm 2 (For example, 60N / mm 2 (over 15%), and 60N / mm 2 (e.g. 42-60N / mm 2 ) is said to be The ultra-high-strength concrete section 14 and the high-strength concrete section 15 are poured into the formwork at different times, but either can be poured first, and one section is poured and hardened after the other section has hardened (it does not have to be completely hardened). In this embodiment, the high-strength concrete section 15 is poured and hardened first.

[0021] 4 and 5, a reinforcing bar cage 16 is embedded within the high-strength concrete portion 15. A portion of the reinforcing bar cage 16 is shown in FIGS. 4 and 5. As shown in FIGS. 4 to 7, the reinforcing bar cage 16 has a plurality of main reinforcing bars 18 arranged at predetermined intervals on the outer peripheral surface 8 side of the segment 2 along the direction of the main girder surface 6, and a plurality of main reinforcing bars 18 also arranged at predetermined intervals on the inner peripheral surface 9 side along the direction of the main girder surface 6. The main reinforcing bars 18 can be made of appropriate deformed bars, knotted steel bars, or other steel bars. These main reinforcing bars 18 arranged above and below (in the thickness direction of the segment 2) are surrounded by and fixed to each other by distribution bars 19 arranged in a direction perpendicular to the main reinforcing bars 18. Multiple sets of distribution bars 19 are provided at predetermined intervals along the longitudinal direction of the main reinforcing bars 18. Both ends of the main reinforcing bars 18 penetrate the wire mesh 17 and extend into the ultra-high strength concrete portion 14.

[0022] 4 and 8, one set of distribution bars 19 has a first distribution bar 19a arranged doubly to completely surround multiple main reinforcing bars 18 arranged vertically. A second distribution bar 19b is arranged in contact with the first distribution bar 19a to surround some of the main reinforcing bars 18 on the left side. Furthermore, a third distribution bar 19c is arranged in contact with the first distribution bar 19a of another set to surround some of the main reinforcing bars 18 on the right side. These distribution bars 19 are arranged alternately in the longitudinal direction of the main reinforcing bars 18. The first to third distribution bars 19a, 19b, and 19c are each wound in a substantially rectangular frame shape in a direction perpendicular to the main reinforcing bars 18. The vertically arranged main reinforcing bars 18 are connected to the first to third distribution bars 19a, 19b, and 19c by welding or the like.

[0023] Within the ultra-high strength concrete section 14, first distribution bars 19a (distribution bars) are arranged to surround the ends of multiple main reinforcing bars 18 (steel members) arranged on the outer surface 8 side and the inner surface 9 side, respectively, and are connected to each other by welding or the like. Furthermore, the M hardware 12 and the F hardware 13 have anchor bars 21 extending into the reinforcing bar cage 16 and fixed to the concrete C of the ultra-high strength concrete portion 14 and the high strength concrete portion 15. The anchor bars 21 may be fixed to or in contact with the reinforcing bar cage 16, or may not be in contact with it.

[0024] Therefore, when an external load such as earth pressure is applied to the joint surfaces 7 of the connected segments 2 in the segment ring 3 of the tunnel 1, the compressive load acting on the abutting joint surfaces 7 is transmitted to the ultra-high strength concrete section 14 and the high strength concrete section 15, and from the main reinforcing bars 18 in the ultra-high strength concrete section 14 to the reinforcing bar cage 16 in the high strength concrete section 15, allowing the load to be shared and borne. Note that reinforcing fibers such as PP fibers may be mixed in advance into one or both of the ultra-high strength concrete portion 14 and the high strength concrete portion 15. Although omitted in the above explanation, sealing grooves and sealing members may be provided on the main girder surface 6 and the upper part of the joint surface 7 of the segment 2 to prevent water leakage.

[0025] The segment 2 according to this embodiment has the above-mentioned configuration, and the method of placing it will now be described with reference to FIG. The formwork 25 shown in Figure 9(a) has a convexly curved base plate 25a that faces the inner peripheral surface 9 of the segment 2, and four side portions 25b that face the opposing main girder surface 6 and joint surface 7. A reinforcing bar cage 16 formed in a lattice pattern from main reinforcing bars 18 and distribution bars 19 is installed within the formwork 25. Male and female joints are fixed to the side portion 25b that faces the main girder surface 6 with screws or the like. M hardware 12 and F hardware 13 are fixed to the side portion 25b of the formwork 25 that faces the joint surface 7 with screws or the like. Furthermore, wire mesh 17 is installed on both sides of the reinforcing bar cage 16 within the formwork 25 as partitions.

[0026] In this state, as shown in Figure 9(b), concrete C is poured through the central opening of lid portion 26 installed within formwork 25 into the space where reinforcing bar cage 16 is placed between opposing wire meshes 17, thereby casting high-strength concrete portion 15. After high-strength concrete portion 15 has hardened, concrete C having a higher cement blend ratio than high-strength concrete portion 15 is poured into the space where main reinforcing bars 18 and first distribution reinforcement bars 19a are placed between wire mesh 17 and side portion 25b facing joint surface 7. Either high-strength concrete portion 15 or ultra-high-strength concrete portion 14 may be poured first. In this way, the high-strength concrete section 15 with a different cement blend ratio and the ultra-high-strength concrete sections 14 on both ends are integrally formed as segment 2, sandwiched between wire mesh 17. After the ultra-high-strength concrete sections 14 have hardened, they are removed from formwork 25, thereby producing the RC segment 2 shown in Figure 9(c).

[0027] The segments 2 manufactured in this manner according to the embodiment are connected at their joint surfaces 7 with M hardware 12 and F hardware 13 in a deep section excavated deep underground to construct a segment ring 3. Furthermore, the main girder surfaces 6 are abutted against each other, and the male and female joints of the joint sections 11 are connected to construct the tunnel 1. Loads such as earth pressure, building load, and groundwater pressure are applied from the outside to the tunnel 1 between the joint faces 7 of adjacent segments 2. Therefore, a large compressive load is applied to the joint faces 7 in particular.

[0028] However, this compressive load can be borne by the ultra-high strength concrete portion 14 having the joint surface 7, and is distributed from the ultra-high strength concrete portion 14 to the high strength concrete portion 15. Moreover, the load is distributed by being transmitted from the main reinforcing bars 18 in the ultra-high strength concrete portion 14 to the main reinforcing bars 18 and distribution bars 19 of the reinforcing bar cage 16 in the high strength concrete portion 15. Therefore, the ultra-high strength concrete portion 14 can prevent the concrete C at the joint surface 7 from breaking. Also, since there are no main reinforcing bars 18 in the concrete portion from the joint surface 7 to the main reinforcing bars 18, and the load is borne only by the concrete, it is set to be partially ultra-high strength concrete for economic reasons.

[0029] Furthermore, since the joint surface 7 is formed from the ultra-high strength concrete section 14 and the M hardware 12 and F hardware 13 are respectively arranged in the center, even if an uneven load is applied in the vertical direction, the load is received by the ultra-high strength concrete section 14, preventing deformation or damage to the M hardware 12 and F hardware 13.

[0030] As described above, according to this embodiment, even if a large compressive load is applied between the joint faces 7 of the segments 2 that constitute the tunnel 1 in the deep section, the load is dispersed from the ultra-high-strength concrete section 14 at the joint face 7 and the internal main reinforcing bars 18 to the high-strength concrete section 15 and the internal reinforcing bar cage 16. This results in high compressive strength and strength for the segments 2. Furthermore, high strength can be achieved without increasing the thickness of the segments 2.

[0031] Furthermore, there is no need to provide compression steel at the joint surface 7 or to place additional reinforcing bars within the segments 2, which reduces manufacturing costs. Furthermore, the M metal fittings 12 and F metal fittings 13 provided in the center of the joint surface 7 are held in place by the ultra-high strength concrete section 14, so that even if a bending load is applied in either the vertical or horizontal direction, the load is dispersed and damage can be prevented. Moreover, the joint surface 7 can be prevented from cracking.

[0032] The segment 2 according to an embodiment of the present invention has been described in detail above, but the present invention is not limited to the above embodiment, and appropriate modifications and substitutions are possible without departing from the spirit of the present invention, and all of these are included in the present invention. Other embodiments and modifications of this embodiment will be described below, but parts and members that are the same or similar to those in the above embodiment will be designated by the same reference numerals and will not be described again.

[0033] Second Embodiment Next, a segment 2A according to a second embodiment of the present invention and a method for placing the same will be described with reference to FIGS. The segment 2A shown in Figures 10 to 12 has an ultra-high-strength concrete section 14 having a joint surface 7 fabricated in advance by a precast construction method. A pair of ultra-high-strength concrete sections 14 are placed in a formwork 25, and high-strength concrete is poured into the center and allowed to harden, forming the high-strength concrete section 15 and the ultra-high-strength concrete section 14 as a single unit. Therefore, no wire mesh 17 is provided at the joint surface 29 between the ultra-high-strength concrete section 14 and the high-strength concrete section 15. It is preferable to roughen the joint surface 29 of the ultra-high-strength concrete section 14 to improve its unity with the high-strength concrete section 15. Alternatively, an uneven surface may be provided at the joint surface 29 between the ultra-high-strength concrete section 14 and the high-strength concrete section 15 to improve its unity with the high-strength concrete section 15 and facilitate adhesion.

[0034] As shown in Figures 11 and 12, the ultra-high strength concrete section 14 produced by the precast method has main reinforcing bars 18a (steel members) arranged inside on the outer peripheral surface 8 side and the inner peripheral surface 9 side, and their ends are fixed to first reinforcing bars 19a by welding or the like. Furthermore, F metal fittings 13 are embedded between the upper and lower main reinforcing bars 18a. Although not shown in the figures, M metal fittings 12 are also embedded in the same way. Alternatively, holes may be drilled in the ultra-high strength concrete section 14 and the F metal fittings 13 and M metal fittings 12 may be inserted and fixed. Main reinforcing bars 18a protrude from the inner surface 14a of the ultra-high strength concrete portion 14 through the joint surface 29, and a mechanical joint 30, for example, is attached to the tip of the main reinforcing bars. Alternatively, a sleeve joint, lap joint, or the like may be connected instead of the mechanical joint 30. Furthermore, the end of the main reinforcing bars 18b provided in the reinforcing bar cage 16 installed in the high strength concrete portion 15 can be connected to the mechanical joint 30. By connecting the main reinforcing bars 18a protruding from the ultra-high strength concrete portion 14 to the end of the main reinforcing bars 18b of the reinforcing bar cage 16 with the mechanical joint 30, a reinforcing bar cage 16 having an integral main reinforcing bar 18 is formed.

[0035] The segment 2A according to this embodiment has the above-described configuration, and the method of placing it will be described with reference to FIG. In the formwork 25 shown in Figure 13(a), precast ultra-high strength concrete sections 14 are placed on both side sections 25b facing the joint surface 7. Next, a reinforcing bar cage 16 is placed between the ultra-high strength concrete sections 14 on both sides, and the ends of its main reinforcing bars 18b are connected to mechanical joints 30 attached to the main reinforcing bars 18a of the ultra-high strength concrete sections 14.

[0036] Next, as shown in Figure 13(b), a lid 26 is installed, high-strength concrete is filled in through the central opening, the reinforcing bar cage 16 is buried, and high-strength concrete sections 15 are poured into the spaces between the ultra-high-strength concrete sections 14. After the high-strength concrete sections 15 have hardened, they are removed from the formwork 25, thereby producing the RC segment 2A shown in Figure 13(c). The resulting segment 2A has no wire mesh 17 at the joint surface 29 between the ultra-high-strength concrete portion 14 and the high-strength concrete portion 15, and the segment 2A has a high degree of integrity. Moreover, because no partition such as wire mesh 17 is provided at the joint surface 29, the aesthetic appearance is not impaired. In addition, by providing an uneven portion at the joint surface 29 between the ultra-high-strength concrete portion 14 and the high-strength concrete portion 15, the integrity of the segment 2A with the high-strength concrete portion 15 can be improved.

[0037] According to the segment 2A of this embodiment, it can be manufactured by pouring concrete into the formwork 25 in one go, so the manufacturing process can be simplified compared to the first embodiment described above.

[0038] Third Embodiment Next, a segment 2B according to a third embodiment of the present invention and a method for placing the same will be described with reference to FIGS. Segment 2B shown in Figures 14 to 18 has a configuration similar to that of segment 2A according to the second embodiment, but differs in the configuration of the main reinforcing bars 18. That is, in segment 2A according to the second embodiment, main reinforcing bars 18a protruding from inner surface 14a are provided in ultra-high strength concrete portion 14, and these main reinforcing bars 18a and main reinforcing bars 18b in high strength concrete portion 15 are connected by mechanical joints 30 to form an integrated main reinforcing bar 18. In contrast, in segment 2B according to the present embodiment, multiple holes H are provided in ultra-high strength concrete portion 14, and main reinforcing bars 18 in high strength concrete portion 15 are inserted through and fixed into holes H in ultra-high strength concrete portion 14. This will be explained in detail below.

[0039] Like the segment 2A of the second embodiment, the segment 2B of this embodiment has an ultra-high-strength concrete section 14 having a joint surface 7 pre-fabricated by a precast construction method. A pair of ultra-high-strength concrete sections 14 are placed in a formwork 25, and high-strength concrete is poured into the center and allowed to harden, forming the high-strength concrete section 15 and the ultra-high-strength concrete section 14 as a single unit. Therefore, in this embodiment, no wire mesh 17 is provided at the joint surface 29 between the ultra-high-strength concrete section 14 and the high-strength concrete section 15. It is preferable to roughen the joint surface 29 of the ultra-high-strength concrete section 14 to improve its integrity with the high-strength concrete section 15. Alternatively, the joint surface 29 between the ultra-high-strength concrete section 14 and the high-strength concrete section 15 may be provided with an uneven surface to improve its integrity and facilitate adhesion.

[0040] The ultra-high strength concrete portion 14 manufactured by the precast method is a substantially flat plate-shaped member, as shown in Fig. 15. A plurality of holes H are formed at predetermined intervals along the direction of the main girder surface 6 on the outer peripheral surface 8 side and the inner peripheral surface 9 side of the inner surface 14a of the ultra-high strength concrete portion 14 (the surface opposite the joint surface 7). Main reinforcing bars 18 (steel members) extending from the high strength concrete portion 15 side are inserted and fixed into these holes H, as shown in Figs. 16 and 17.

[0041] Here, the inner diameter of the hole H is formed to be larger than the outer diameter of the main reinforcing bar 18. In addition, the depth of the hole H is formed to be deeper than the length of the end of the main reinforcing bar 18. This is so that the end of the main reinforcing bar 18 can be inserted into the hole H even if there is some misalignment of the main reinforcing bar 18 due to an assembly error of the reinforcing bar cage 16. Furthermore, the gap between the hole H and the main reinforcing bar 18 is filled with high-strength concrete, and the main reinforcing bar 18 is fixed in the hole H.

[0042] As shown in FIG. 17, in segment 2B of this embodiment, F hardware 13 is embedded between hole H formed on the outer peripheral surface 8 side and hole H formed on the inner peripheral surface 9 side. Although not shown in the figure, M hardware 12 is also embedded in the same way. Alternatively, holes may be drilled in the ultra-high strength concrete portion 14 and the F hardware 13 and M hardware 12 may be inserted and fixed. Although not shown in FIGS. 16 and 17, reinforcing bars 19a may be provided inside the ultra-high strength concrete portion 14, as in segment 2A of the second embodiment.

[0043] The segment 2B according to this embodiment has the above-described configuration, and the method of placing it will be described with reference to FIG. In the formwork 25 shown in Figure 18(a), precast ultra-high strength concrete sections 14 are placed on both side sections 25b facing the joint surface 7. Next, a reinforcing bar cage 16 is placed between the ultra-high strength concrete sections 14 on both sides, and the ends of the main reinforcing bars 18 are inserted into holes H formed in the ultra-high strength concrete sections 14.

[0044] At this time, the inner diameter of the hole H is formed to be larger than the outer diameter of the main reinforcing bar 18. In addition, the depth of the hole H is formed to be deeper than the length of the end of the main reinforcing bar 18. Therefore, even if there is some misalignment of the main reinforcing bar 18 due to an assembly error of the reinforcing bar cage 16, the end of the main reinforcing bar 18 can be inserted through the hole H. This improves workability.

[0045] Next, as shown in Figure 18(b), the lid 26 is installed, high-strength concrete is filled in through the central opening to bury the reinforcing bar cage 16, and high-strength concrete sections 15 are poured into the spaces between the ultra-high-strength concrete sections 14. At this time, high-strength concrete is also filled into the gaps between the holes H and the main reinforcing bars 18. After the high-strength concrete sections 15 have hardened, they are removed from the formwork 25, thereby producing the RC segment 2B shown in Figure 18(c).

[0046] Like the segment 2A of the second embodiment, the obtained segment 2B has no wire mesh 17 at the joint surface 29 between the ultra-high-strength concrete portion 14 and the high-strength concrete portion 15, and the segment 2B has a high degree of integrity. Moreover, because no partition such as wire mesh 17 is provided at the joint surface 29, the aesthetic appearance is not impaired. Furthermore, by providing an uneven portion at the joint surface 29 between the ultra-high-strength concrete portion 14 and the high-strength concrete portion 15, the integrity of the segment 2B with the high-strength concrete portion 15 can be improved.

[0047] Segment 2B according to this embodiment can be manufactured by pouring concrete into formwork 25 in a single operation, simplifying the manufacturing process compared to the first embodiment. Furthermore, with segment 2B of this embodiment, it is only necessary to insert the ends of main reinforcing bars 18 into holes H formed in ultra-high-strength concrete portion 14, and there is no need to connect main reinforcing bars 18a protruding from ultra-high-strength concrete portion 14 to main reinforcing bars 18b in high-strength concrete portion 15 using mechanical joints 30, as in segment 2A of the second embodiment. This further simplifies the manufacturing process compared to the second embodiment.

[0048] It is also possible to provide another reinforcing bar cage inside the ultra-high strength concrete section 14, in which case the main reinforcing bars are connected directly or via a joint to the reinforcing bar cage 16 inside the high strength concrete section 15. Furthermore, the ultra-high strength concrete section 14 does not have to be connected to the reinforcing bar cage 16 inside the high strength concrete section 15. The segments 2, 2A, and 2B according to the above-described embodiments and the casting method thereof are included in the concrete members and casting methods thereof. The concrete members also include flat members that are not curved like an arc or have other suitable shapes. The end faces also include joint surfaces 7. [Explanation of symbols]

[0049] 2B segment 3 segment ring 6 Main girder surface 7 Joint surface 14 Ultra-high strength concrete section 14a Inner surface 15 High-strength concrete section 16 Reinforced Concrete Cage 18 Main reinforcing bars 25 Formwork C. Concrete H hole

Claims

1. A concrete member having opposing end faces, A high-strength concrete section with a reinforced concrete cage inside; precast ultra-high strength concrete sections that are disposed on both sides of the high strength concrete section and have the end faces, respectively, and that have higher strength than the high strength concrete sections; Equipped with a hole is formed in the surface of the ultra-high strength concrete portion opposite to the end surface, The reinforcing bars of the reinforcing bar cage are inserted into the holes and fixed. A concrete member characterized by:

2. 2. The concrete member according to claim 1, wherein the ultra-high strength concrete portion has a higher cement blending ratio than the high strength concrete portion.

3. A cylindrical wall is constructed by connecting a plurality of arc-shaped segments at concrete joint surfaces and main girder surfaces, A high-strength concrete section with a rebar cage inside, a precast ultra-high strength concrete section connected to both sides of the high strength concrete section, having a higher strength than the high strength concrete section and having a hole formed on a surface facing the high strength concrete section; Equipped with The reinforcing bars of the reinforcing cage are inserted and fixed in the holes of the ultra-high strength concrete section. A segment characterized by:

4. 1. A method for placing a concrete member having opposing end faces, comprising: a step of positioning and placing precast ultra-high strength concrete having the end surface and a hole formed in a surface opposite the end surface within a formwork so that the surfaces with the hole formed face each other; a step of disposing a reinforcing bar cage between the ultra-high strength concrete in the formwork and inserting reinforcing bars of the reinforcing bar cage into the holes formed in the ultra-high strength concrete; A step of pouring concrete into a space sandwiched between the ultra-high strength concrete in the formwork, thereby pouring high strength concrete having a strength lower than that of the ultra-high strength concrete; A method for pouring a concrete member, comprising:

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