Reinforced concrete steel structure

Abstract

To provide a reinforced concrete structure capable of enhancing anchoring strength between reinforcement and concrete and joint strength of a lap joint with a simple structure.SOLUTION: A reinforced concrete structure 1 includes a plurality of expanded diameter bearing parts 5 and 5 having diameters larger than those of reinforcements at an interval in a longitudinal direction of reinforcements 3, wherein the expanded diameter bearing parts 5 are composed of movable expanded diameter bearing bodies composed of a plurality of nut type members 6 and 7 screwed with a screw part formed in the reinforcements 3, the nut type member 7 is fastened to the side of the other adjacent nut type member 6, and the movable expanded diameter bearing bodies are fixed to desires positions of the reinforcements 3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a reinforcing bar structure of reinforced concrete used for gap lap joints and reinforcing bar anchorage. [Background technology]

[0002] In conventional reinforced concrete structures, lap joints are widely used to connect reinforcing bars embedded in concrete.

[0003] In a lap joint, the reinforcing bars to be joined overlap each other by the required length (joint length), so that the tensile force between the reinforcing bars is transmitted to each reinforcing bar via its adhesion to the concrete.

[0004] In this type of lap joint, the joint length is generally set to about 30 to 35 times the diameter of the rebar, so the larger the diameter of the rebar, the longer the joint length becomes, which poses a problem of significantly reducing workability.

[0005] Therefore, when the diameter of the reinforcing bars is large, mechanical joints, gas pressure welding joints, enclosed welding, etc. have often been used as joints to connect the reinforcing bars.

[0006] Another type of lap joint is a gap lap joint, in which a gap is provided between the reinforcing bars so that the reinforcing bars do not come into contact with each other.

[0007] This gap lap joint can be treated as equivalent to a lap joint if it meets certain criteria, namely, the criteria that the gap is 0.2L1 and 150 mm or less with respect to the joint length L1.

[0008] Meanwhile, in the construction of deck slabs, in addition to the typical method using loop joints, a method is currently being used in which the ends of the reinforcing bars protruding from the opposing end faces of precast deck slab components that are placed abutting each other at a specified distance are overlapped, and concrete is poured into that area to connect the precast deck components.

[0009] In this type of construction method, a joint structure has been developed in which a head with a diameter larger than the diameter of the rebar is provided at the end of the rebar protruding from the end face of the precast deck member, and the length of the overlapping part (joint length) is made shorter than conventional lengths due to the combined action of the adhesion force with the concrete and the bearing resistance force acting on the head (see, for example, Patent Document 1).

[0010] Furthermore, at the joints between structural components that make up a structure, such as the joint between a concrete beam and a concrete column, in order to ensure sufficient joint strength between the two structures, it is necessary to anchor the ends of the reinforcing bars embedded in one structure to the other structure.In such cases, the reinforcing bars anchored to the concrete column are bent into an L-shape to ensure sufficient anchorage length.

[0011] However, at the anchoring point of the reinforcing bar, there are cases where it is difficult to secure enough space to bend the reinforcing bar.In such cases, a head with a larger diameter than the diameter of the reinforcing bar is provided at the end of the reinforcing bar to be anchored to the other structure, and the anchoring length is shortened by utilizing the bearing resistance force acting on the head. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-11940 Summary of the Invention [Problem to be solved by the invention]

[0013] However, in the conventional technologies described above, joint structures such as mechanical joints, gas pressure welding joints, and enclosed welding, which are used when the diameter of the reinforcing bars is large, have the problem that the structure and construction are large-scale, which increases costs, and there is also the problem that they are less easy to construct than lap joints.

[0014] On the other hand, the gap lap joint structure in which a head is provided at the end of the reinforcing bar used in deck construction allows the joint length to be shorter than a general lap joint structure, but it is difficult to install such a head at the construction site, and the head is fixed to the end of the reinforcing bar in advance at the factory by crimping or welding, etc., so the position of the head cannot be freely set at the construction site, and there is a problem that it cannot be accommodated if there is a need to adjust the joint length during construction.

[0015] Furthermore, when joining structures, a similar problem may occur when providing heads to the reinforcing bars at the anchoring points.

[0016] Therefore, in consideration of these conventional problems, the present invention has been made with the aim of providing a reinforced concrete structure that can increase the anchorage strength between the reinforcing bars and concrete and the joint strength of gap lap joints with a simple structure. [Means for solving the problem]

[0017] The feature of the invention described in claim 1 to solve the above-mentioned conventional problems is as follows: The ends of the reinforcing bars arranged in the longitudinal direction in the concrete, or in the mortar or concrete filled between the concrete members, are overlapped by a predetermined length to form a gap lap joint, In a reinforced concrete structure in which the reinforcing bar is provided with an expanded bearing part with a diameter larger than the reinforcing bar diameter, At the end of the rebar that will be overlapped The reinforcing bar is provided with a plurality of expansion-diameter support sections spaced apart in the longitudinal direction thereof, and at least one of the plurality of expansion-diameter support sections is constituted by a movable expansion-diameter support body consisting of a plurality of nut-shaped members screwed onto threaded portions formed on the reinforcing bar, and at least one of the plurality of nut-shaped members is fastened to another adjacent nut-shaped member, so that the movable expansion-diameter support body is fixed at a desired position on the reinforcing bar.

[0018] The invention described in claim 2 is characterized in that in a reinforced concrete structure, in which concrete, mortar filled between concrete members, or reinforcing bars embedded in concrete are provided with enlarged bearing parts having a diameter larger than the diameter of the reinforcing bars, At the joints between structures that make up a reinforced concrete structure, the part where the reinforcing bars supported by one structure are fixed into another structure.The reinforcing bar is provided with a plurality of expansion-diameter support sections spaced apart in the longitudinal direction thereof, and at least one of the plurality of expansion-diameter support sections is constituted by a movable expansion-diameter support body consisting of a plurality of nut-shaped members screwed onto threaded portions formed on the reinforcing bar, and at least one of the plurality of nut-shaped members is fastened to another adjacent nut-shaped member, so that the movable expansion-diameter support body is fixed at a desired position on the reinforcing bar.

[0019] Claim 3 The invention described in is characterized by: Claim 1 or 2 In addition to the above configuration, all of the plurality of expanded diameter support portions are formed by the movable expanded diameter support bodies.

[0020] Claim 4 The invention described in is characterized by: Claims 1-3 In addition to any one of the above configurations, the spacing between the enlarged bearing portions is set to be equal to or larger than the maximum aggregate size of the concrete.

[0021] Claim 5 The invention described in is characterized by: Claim 4 In addition to the above configuration, the spacing between the plurality of enlarged diameter bearing portions is 1 to 3 times the diameter of the reinforcing bar.

[0022] Claim 6 The invention described in is characterized by: Claims 1 to 5 In addition to any one of the above configurations, the movable diameter expansion support body has a torque strength of 20 Nm or more and 180 Nm or less when tightening the nut-shaped member.

[0023] Claim 7 The invention described in is characterized by: Claims 1 to 6 In addition to any one of the above configurations, the reinforcing bar is a threaded reinforcing bar having a threaded portion formed all over it. [Effects of the Invention]

[0024] By providing the reinforced concrete structure of the present invention with the configuration of claim 1, the combined action of the adhesion force acting on the straight sections of the reinforcing bars and the bearing resistance force acting on the enlarged bearing sections can enhance anchorage to the concrete, and the positions of the enlarged bearing sections can be determined arbitrarily at the construction site, improving workability. In addition, the bearing resistance force exerted by multiple enlarged bearing sections can further enhance anchorage to the concrete. In addition, since the enlarged bearing portions of adjacent reinforcing bars support each other through bearing resistance, the joint length can be made shorter than that of conventional lap joints.

[0025] Furthermore, in the present invention, Claim 2 By adopting this configuration, the anchorage length of the reinforcing bars can be reduced compared to conventional methods when joining the structures that make up a reinforced concrete structure.

[0026] In addition, in the present invention, Claim 3 By adopting this configuration, when design changes or fine adjustments are required at the construction site, the position of the expanded diameter bearing section can be freely set to an effective position for exerting bearing resistance force.

[0027] In addition, in the present invention, Claims 4 to 5 By providing the above configuration, concrete can be suitably filled.

[0028] In addition, in the present invention, Claim 6 By providing this configuration, it is possible to introduce a tightening force into the movable expansion bearing body so that a resistance force greater than the bond stress between the concrete and the reinforcing bar can be obtained by human power.

[0029] In addition, in the present invention, Claim 7 By adopting this configuration, the bearing area coefficient of the threaded reinforcing bar, i.e., the protruding area of the reinforcing bar surface per unit area, is large, so that higher adhesion performance to concrete can be obtained compared to deformed reinforcing bars, etc. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a longitudinal cross-sectional view showing an example of a reinforced concrete structure according to the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along the line AA of the same. [Figure 3] This is a schematic diagram of steel bar arrangement to explain the effect of the bearing resistance force by the expanded diameter bearing section of the same. [Figure 4] 1(a) is a schematic diagram of the rebar arrangement showing the state where the expansion support part of the same has shifted in position, and FIG. 1(b) is a schematic diagram of the rebar arrangement showing the state where the movable expansion support body has been aligned. [Figure 5] 1(a) is a graph showing the results of a pull-out strength experiment on the movable expansion bearing body of the same, and FIG. 1(b) is a front view showing an outline of the same experimental device. [Figure 6] 1A is a plan view showing an example of a nut-shaped member constituting the movable diameter expansion support body of the same, and FIG. 1B is a side view of the same. [Figure 7] 10 is a graph showing the results of an adhesion performance test between the reinforced concrete structure according to the present invention and concrete. [Figure 8] 10 is a graph showing the load sharing between the adhesive force of the reinforcing bar and the support pressure by the movable expansion support body. [Figure 9] FIG. 2 is a vertical cross-sectional view showing another example of a reinforced concrete structure according to the present invention. [Figure 10] FIG. 2 is a cross-sectional view taken along the line AA of the same. [Figure 11] FIG. 1(a) is a longitudinal sectional view showing another example of a reinforced concrete structure according to the present invention, and FIG. 1(b) is a longitudinal sectional view showing a conventional reinforced concrete structure. DETAILED DESCRIPTION OF THE INVENTION

[0031] Next, a first embodiment of a reinforced concrete structure according to the present invention will be described based on the example shown in Figures 1 to 4. In the figures, reference numeral 1 denotes a reinforced concrete structure.

[0032] This reinforced concrete structure 1 has reinforcing bars 3, 3 buried in concrete 2, and the reinforcing bars 3, 3 connected in the longitudinal direction are connected by open lap joints, so that the axial force acting on each reinforcing bar 3, 3 is transmitted via the concrete 2. Note that the reference symbol 4 in the figure denotes horizontal reinforcement arranged in a direction that intersects with the reinforcing bars 3.

[0033] In a gap lap joint, the ends of the reinforcing bars 3, 3 connected in the longitudinal direction are arranged with a predetermined gap (gap) between them and overlapped by a predetermined length in the longitudinal direction (joint length = L1), so that the axial force acting on each reinforcing bar 3, 3 is transmitted through the concrete 2.

[0034] Furthermore, this lap joint can be treated the same as a general lap joint because the spacing between the reinforcing bars 3, 3 meets specified standards (spacing of 0.2L1 and 150 mm or less for the joint length L1).

[0035] The reinforcing bars 3,3 have a plurality of enlarged bearing sections 5,5 with a diameter larger than the diameter of the reinforcing bars spaced apart in the longitudinal direction, and form a structure in which the bearing resistance force of the enlarged bearing sections 5,5 of adjacent reinforcing bars 3,3 supports each other.

[0036] The reinforcing bar 3 is preferably a threaded reinforcing bar having a male thread formed at least at the end and a male thread formed all over the reinforcing bar. Note that the reinforcing bar 3 is not limited to a threaded reinforcing bar, and may be a general reinforcing bar such as an epoxy resin coated reinforcing bar with a male thread formed thereon.

[0037] The expansion support section 5,5 is composed of a movable expansion support body consisting of multiple (a pair in this embodiment) nut-type members 6,7 screwed onto the threaded portion, and at least one of the multiple nut-type members 6,7 (nut-type member 7 in this embodiment) can be fastened to an adjacent other nut-type member 6 to fix it in a predetermined position on the reinforcing bar 3.

[0038] The positions of the expanded support sections 5,5 are adjusted so that the corresponding expanded support sections 5,5 of adjacent reinforcing bars 3 are positioned in the direction in which the compressive stress transfer area (compression strut) is formed (the direction forming an angle of approximately 45 degrees with the reinforcing bars 3) and in a position where the compressive stress transfer areas overlap, allowing the expanded support sections 5,5 of adjacent reinforcing bars 3,3 to support each other.

[0039] In this embodiment, the case where the diameter expansion support portions 5, 5 are provided at two locations will be described, but the diameter expansion support portions 5 can be provided at up to three locations.

[0040] In this embodiment, all of the expanded diameter support portions 5, 5 are configured by movable expanded diameter support bodies, and all of the expanded diameter support portions 5, 5 can be set at any position relative to the reinforcing bars 3, 3.

[0041] The nut-type members 6, 7 are made of commonly used hexagonal nuts or the like, and are screwed onto the reinforcing bars 3 so that they are fastened in different directions. Both nut-type members 6, 7 are threaded forward to move them to the desired positions on the reinforcing bars 3, 3, and one nut-type member 6 is fastened to the other nut-type member 7 with a predetermined torque (fastening strength), whereby the nut-type members 6, 7 engage with the male threads and are fixed in place. Note that the shape of the nut-type members 6, 7 is not limited to hexagonal nuts, and disk-shaped, oval-shaped, rectangular, or other shapes can also be used.

[0042] The nut-shaped members 6 and 7 may be tightened in different directions to introduce torque into both the nut-shaped members 6 and 7.

[0043] The tightening strength of the nut-shaped members 6, 7 is set to 20 Nm or more and 180 Nm or less. By introducing a torque of 20 Nm or more, it is possible to obtain a nut slippage resistance greater than the bond stress between the reinforcing bar 3 and the concrete 2, and by setting it to 180 Nm or less, it is possible to prevent damage to the screws formed in the reinforcing bar 3.

[0044] Figure 5(a) shows the results of an experiment verifying the relationship between the sliding resistance force between the movable expansion bearing body and the threaded reinforcing bar.

[0045] In this experiment, a torque wrench was used to apply torques of 20, 120, and 180 Nm between the nut-shaped members 6 and 7, and the device shown in Figure 5(b) was used to measure the displacement (nut displacement) δ of the nut member 6 relative to the reinforcing bar 3 when a static pull-out load P was applied to the reinforcing bar 3.

[0046] In the figure, the symbol 8 is a displacement meter. When a pull-out load P is applied to the reinforcing bar 3 and a misalignment occurs between the reinforcing bar 3 and the nut-shaped member 6, the displacement meter 8 is pushed in and the displacement of the pushed-in amount is measured as the nut misalignment δ.

[0047] As shown in FIG. 6, the nut-shaped members 6 and 7 were hexagonal nuts having a nominal diameter d of 19 mm, a width across flats of s of 31 mm, and a diagonal distance e of 32.6 mm.

[0048] The pull-out load P varies depending on the applied torque. For example, the bond stress equivalent when the free end slip shown by the vertical dotted line on the left side of Figure 5(a) is 0.2% of the rebar diameter is converted as shown.

[0049] Here, the bond stress between the reinforcing bar and concrete is designed using the following formula, so the bond stress between normal concrete and reinforcing bar is generally 2.1 to 3.8 N / mm 2 is.

number

[0050] Therefore, from Figure 5(a), it can be seen that a torque of 20 Nm or more must be introduced into the movable expansion bearing body.

[0051] Moreover, the distance between the expanded diameter bearing portions 5, 5 is set to be equal to or larger than the maximum aggregate size of the concrete 2, and is preferably set to be 1 to 3 times the diameter of the reinforcing bar.

[0052] In the reinforced concrete structure 1 configured in this manner, by providing multiple expanded support sections 5, 5 at the overlapping portions of the reinforcing bars 3, 3 of the gap lap joint, in addition to increasing the bond strength between the reinforcing bars 3, 3 themselves (straight sections) and the concrete 2, as shown in Figure 3, a compressive stress transfer area (compression strut) X is formed in a predetermined direction (a direction forming an angle of approximately 45 degrees with the reinforcing bars) in the expanded support sections 5, 5 attached to adjacent reinforcing bars 3, 3, and the expanded support sections 5, 5 support each other, so that the joint length can be reduced to about one-third of that of a general lap joint without using a mechanical joint.

[0053] Furthermore, in this reinforced concrete structure 1, the expanded diameter support sections 5,5 are constructed from movable expanded diameter support bodies consisting of multiple nut-shaped members 6,7, so that the expanded diameter support sections 5,5 are not completely integrated with the reinforcing bars 3,3, and by tightening the nut-shaped members 6,7, a nut slippage resistance greater than the bond stress between the reinforcing bars 3,3 and the concrete 2 can be obtained.

[0054] Therefore, at the construction site, the position of the expanded support section 5,5 relative to the reinforcing bars 3,3 can be set arbitrarily, and changes caused by malfunctions or design changes, such as misalignment of the reinforcing bars 3,3 in the axial direction or changes in the width between adjacent reinforcing bars 3,3, can be flexibly accommodated.

[0055] For example, as shown in Figure 4(a), if there is a misalignment between the reinforcing bars 3, 3 in the axial direction of the reinforcing bars due to a change in the specifications of the reinforcing bar arrangement position, as compared to the arrangement of the reinforcing bars 3, 3 shown in Figure 3, the corresponding expanded support sections 5, 5 of adjacent reinforcing bars 3, 3 may fall outside the compressive stress transmission area (compression strut) X, and an effective support effect may not be achieved.

[0056] However, in the present invention, as shown in Figure 4(b), the position can be easily adjusted by moving and tightening the nut-type members 6, 7 at the construction site, so that the support effect of the expanded diameter support section 5 can always be effectively exerted.

[0057] Next, the results of the bond performance test of the reinforcing bars in the reinforced concrete structure according to the present invention will be described.

[0058] In this performance test, the reinforcing steel structure to be used as the test specimen was embedded in ordinary concrete (50N), and a pull-out load P was applied to the free end of the specimen, and the relationship between the load and the free end slippage S0 was measured. Note that when the free end slippage is the same, the greater the pull-out load, the higher the pull-out resistance (bond performance).

[0059] This test was conducted using five test specimens: one containing only deformed rebars; one containing only threaded rebars; one containing a single movable expansion support body consisting of a pair of nut-shaped members attached to the threaded rebar (hereinafter referred to as threaded rebar + nut 1); one containing two movable expansion support bodies consisting of a pair of nut-shaped members attached to the threaded rebar (hereinafter referred to as threaded rebar + nut 2); and one containing two movable expansion support bodies with a large distance between them (hereinafter referred to as threaded rebar + nut 2').

[0060] In addition, in this performance test, the support pressure of the movable expansion bearing body was estimated by comparing the pull-out load P at a specified free end slippage S0 between the cases of threaded rebar + nut 1, threaded rebar + nut 2, and threaded rebar + nut 2' and the case of threaded rebar alone, and the load sharing between the adhesion force of the rebar and the support pressure by the movable expansion bearing body was also examined.

[0061] As shown in Figure 7, as is clear from the index known as the bearing area coefficient BA (the protruding area of the rebar surface per unit area), threaded rebars have a larger protruding area than deformed rebars and are easier to fill between the nodes, so the pull-out load of threaded rebars is greater than that of deformed rebars.

[0062] Next, when comparing the deformed rebar and the threaded rebar + nut 1, when the free end slippage was 0.02 mm (equivalent to 0.1% of the rebar diameter), the pull-out load for the threaded rebar + nut 1 was 1.4 times higher, confirming that the movable expanding support body improves pull-out resistance.

[0063] Furthermore, when there are two movable expansion bearing bodies, such as the threaded rebar + nut 2 and the threaded rebar + nut 2', the pull-out load becomes 1.6 times larger than that of the deformed rebar.

[0064] However, the pull-out load was larger for the screw-knotted rebar + nut 2 than for the screw-knotted rebar + nut 2', and the pull-out performance was better when the distance between the movable expansion bearing bodies was narrow.

[0065] On the other hand, with regard to the load sharing between the adhesive force of the rebar and the bearing pressure of the movable expansion bearing body, in the case of the threaded rebar + nut 1, the adhesive force is the cause of the pull-out load in the initial step, and as the displacement step progresses, the effect of the bearing pressure begins to be exerted, as shown in Figure 8. This is because the adhesive force is exerted from the loaded end of the rebar to the free end, and so the load is not transmitted to the movable expansion bearing body in the initial step.

[0066] On the other hand, in the case of the screw-knotted rebar + nut 2 (2'), the bearing pressure accounts for 30% of the total tensile load from the initial step, and it can be seen that the effect of the movable expanding diameter bearing body is exerted from the beginning.

[0067] In other words, it was confirmed that when two movable expansion bearing bodies were installed, the initial gradient of the load-displacement relationship was large and the initial slippage of the reinforcing bars was small.

[0068] 9 and 10, this gap lap joint is also applicable to the case where reinforced concrete members 20, 20 with reinforcing bars 3 embedded therein are placed at a distance from each other and a filler material 21 made of concrete or mortar is filled between the two concrete members 20, 20. The same components as those in the above-mentioned embodiment are designated by the same reference numerals and their explanations are omitted.

[0069] In this embodiment, the ends of the reinforcing bars 3 protrude from the end faces of the concrete members 20, 20 to be connected to each other, and the protruding portions are arranged with a predetermined gap between the reinforcing bars 3, 3 and overlapping by a predetermined length in the longitudinal direction (joint length = L1), so that the axial force acting on each reinforcing bar 3, 3 is transmitted via a filler 21 made of concrete or mortar filled between the concrete members 20, 20.

[0070] Furthermore, when the filler 21 is concrete, it is preferable that the spacing between the diameter support portions 5, 5 be greater than or equal to the maximum aggregate dimension of the concrete 2, but when mortar is used as the filler 21, the spacing between the diameter expansion support portions 5, 5 is not particularly limited.

[0071] Next, a second embodiment of the reinforced concrete structure according to the present invention will be described with reference to Fig. 9. In the figure, reference numeral 10 denotes the reinforced concrete structure.

[0072] This reinforced concrete structure 10 has a structure in which a concrete beam 12 (one structure) is joined to the side of a reinforced concrete column 11 (another structure), and the ends of reinforcing bars 13, 13 embedded in the concrete beam 12 are fixed inside the concrete column 11. In the figure, reference numeral 14 denotes the longitudinal main reinforcement of the concrete column 11.

[0073] The reinforcing bars 13, 13 embedded in the concrete beam 12 have multiple expanded support sections 15, 15 at their ends, spaced longitudinally, with diameters larger than the diameter of the reinforcing bars, and the ends of the reinforcing bars 13 including the multiple expanded support sections 15, 15 are fixed to the concrete column 11.

[0074] The reinforcing bars 13, 13 are preferably threaded reinforcing bars having male threads formed at least at the ends and having male threads formed over the entire length.

[0075] The expanded diameter support portions 15, 15 are composed of movable expanded diameter support bodies consisting of multiple nut-type members 16, 17 screwed onto the threaded portions, and can be fixed in a predetermined position on the reinforcing bars 13, 13 by tightening at least one of the multiple nut-type members 16, 17 to the side of the adjacent other nut-type member 16.

[0076] Therefore, in this reinforced concrete structure 10, a high anchorage force can be obtained due to the bearing resistance force acting on the expanded bearing sections 15, 15, and the anchorage length of the reinforcing bars 13, 13 can be significantly reduced compared to conventional reinforcing bars 18, 18, which were bent into an L-shape as shown in Figure 9(b) to ensure the anchorage length.

[0077] In this case, the positions of the expanded diameter support sections 15, 15 can be set at any position on the reinforcing bars 13, 13, so when assembling the reinforcing bars 13, 13, the positions of the expanded diameter support sections 15, 15 can be flexibly adjusted at the construction site to match the positions of the reinforcing bars 14, 14 buried in the concrete pillar 11.

[0078] The aspects of the present invention are not limited to the above-described embodiments, and may be applied to, for example, joints between precast concrete members. [Explanation of symbols]

[0079] 1. Reinforced concrete structures 2. Concrete 3. Reinforced concrete 4 Reinforcement bars (horizontal bars) 5 Expanded bearing section 6,7 Nut-type member 10 Reinforced concrete structures 11 Concrete pillar 12 Concrete beams 13 Reinforced concrete 14 Reinforced concrete 15 Expanded bearing section 16,17 Nut-type member 18 Reinforced concrete 20 Concrete members 21 Filling material

Claims

1. In a reinforced concrete structure, the ends of reinforcing bars connected longitudinally in concrete, or in mortar filled between concrete members, or in concrete are overlapped by a predetermined length to form lap joints, and the reinforcing bars are provided with enlarged bearing sections with a diameter larger than the diameter of the reinforcing bars, A reinforced concrete reinforcing bar structure characterized in that the ends of the overlapping reinforcing bars are provided with a plurality of expanded diameter support sections spaced apart in the longitudinal direction of the reinforcing bars, at least one of the plurality of expanded diameter support sections is constituted by a movable expanded diameter support body consisting of a plurality of nut-shaped members screwed onto threaded portions formed on the reinforcing bars, and at least one of the plurality of nut-shaped members is tightened to another adjacent nut-shaped member so that the movable expanded diameter support body is fixed at a desired position on the reinforcing bars.

2. In a reinforced concrete structure, the reinforced concrete is provided with an expanded bearing section with a diameter larger than the diameter of the reinforcing bar, in concrete, or in mortar filled between concrete members, or in concrete. A reinforced concrete reinforcing structure characterized in that at the joints between structures that make up a reinforced concrete structure, a plurality of expansion bearing sections are provided at intervals in the longitudinal direction of the reinforcing bar at the portion where the reinforcing bar supported by one structure is fixed into another structure, and at least one of the plurality of expansion bearing sections is constituted by a movable expansion bearing body consisting of a plurality of nut-shaped members screwed onto threaded portions formed on the reinforcing bar, and at least one of the plurality of nut-shaped members is tightened to another adjacent nut-shaped member so that the movable expansion bearing body is fixed at a desired position on the reinforcing bar.

3. 3. A reinforced concrete structure according to claim 1, wherein all of the plurality of expansion bearing sections are constituted by the movable expansion bearing bodies.

4. 4. A reinforced concrete structure according to claim 1, wherein the spacing between the expanded bearing sections is equal to or greater than the maximum aggregate size of the concrete.

5. 5. The reinforced concrete structure according to claim 4, wherein the spacing between the plurality of expanded diameter bearing sections is 1 to 3 times the diameter of the reinforcing bar.

6. The reinforced concrete structure according to any one of claims 1 to 5, wherein the movable expansion support body has a torque strength of 20 Nm or more and 180 Nm or less when tightening the nut-shaped member.

7. 7. A reinforced concrete structure according to claim 1, wherein the reinforcing bar is a threaded reinforcing bar having a threaded portion formed throughout the entire structure.

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