Reinforcement structure and reinforcement method

Abstract

To provide a reinforcing structure or the like having high bearing capacity.SOLUTION: A reinforcing structure 1 reinforces an existing bridge pier 2 provided on a base slab 3. The reinforcing structure 1 includes, on the base slab 3, a concrete 11 provided around the outer peripheral part of the bridge pier 2 such that a bottom part 11a is widened outwardly concerning an upper part 11b thereof; a reinforcing main reinforcement 12 arranged in a vertical direction over a bottom part 11a and an upper part 11b of the concrete 11, in the concrete 11, and having a lower end part anchored in the bottom part 11a of the concrete 11; and an anchor reinforcement 13 whose lower end is fixed to the base slab 3 and which is buried in the bottom part 11a of the concrete 11. An anchoring part 131 is provided at the upper end of an anchor reinforcement 13.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a reinforcement structure and a reinforcement method for a pillar member. [Background technology]

[0002] Patent Document 1 describes a reinforcement structure for existing bridge piers in which root-wrapped concrete and lining concrete are placed around the outer periphery of the pier, axial steel bars are embedded in the concrete, and the root-wrapped concrete is fixed to the footing with PC steel bars. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6427045 Summary of the Invention [Problem to be solved by the invention]

[0004] The above reinforcement structure can improve the bending strength of bridge piers, making it possible to reinforce bridge piers against earthquakes. However, larger bending occurs in large bridge piers, and a reinforcement structure that can withstand such large bending is needed. For example, as the pier bends, tensile force acts on the axial reinforcing bars, and if this tensile force causes cone-shaped fracture in the concrete encasing the pier, there is a risk of a decrease in strength.

[0005] The present invention has been made in view of the above problems, and has an object to provide a reinforced structure or the like with high strength. [Means for solving the problem]

[0006] The first invention to solve the above-mentioned problems is , baseThis is a reinforcement structure for an existing column member placed on a foundation slab, comprising: concrete placed on the outer periphery of the column member on the foundation slab so that the bottom expands outward relative to its upper part; main reinforcing bars arranged vertically within the concrete from the bottom to the upper part of the concrete, with their lower ends fixed within the bottom of the concrete; and anchor steel bars whose lower ends are fixed to the foundation slab and embedded within the bottom of the concrete, with fixing parts provided at the upper ends of the anchor steel bars, and horizontal steel bars protruding from the column member are embedded in the bottom of the concrete, and the fixing parts are positioned so as to engage with the horizontal steel bars.

[0007] In this invention, existing column members are reinforced by providing concrete around the periphery of the column members, embedding the main reinforcing bars in the concrete to anchor them into the bottom of the concrete, and then fixing the bottom of the concrete to the base slab with anchor rebars. In particular, since anchorages are provided at the upper ends of the anchor rebars, when a tensile force acts on the main reinforcing bars as the column member bends, cone-shaped fractures at the bottom of the concrete due to the tensile force are prevented, thereby improving the bearing capacity.

[0008] Also a book In the present invention, the horizontal reinforcing bars connect the column members and concrete, preventing them from separating during earthquakes, etc. Also, by locking the anchoring parts of the anchor reinforcing bars to the horizontal reinforcing bars, it becomes easier to arrange the anchor reinforcing bars.

[0009] It is desirable that the anchor rebars be arranged in more stages than the main reinforcing bars in the width direction of the column member. The anchor rebars have a smaller diameter than the main reinforcing bars, for example. In this invention, the tensile force generated in the main reinforcing bars is transmitted to the bottom of the concrete by anchoring the main reinforcing bars to the bottom, and the tensile force is distributed and transmitted to the foundation slab by multiple anchor rebars. Therefore, rebars with lower strength than the main reinforcing bars can be used as anchor rebars. For example, using anchor rebars with smaller diameters makes it easier to install the anchor rebars in the foundation slab.

[0010] No. 2 The invention is 1 of A method for reinforcing an existing column member using the reinforcing structure of the invention, characterized by comprising the steps of: arranging the main reinforcing bars and the anchor steel bars on the outer periphery of the column member; and pouring the concrete on the outer periphery of the column member. [Effects of the Invention]

[0011] The present invention can provide a reinforced structure or the like with high strength. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram showing an outline of a reinforcing structure 1. FIG. [Figure 2] FIG. 1 is a diagram showing a reinforcing structure 1. [Figure 3] FIG. 2 is a diagram showing a horizontal cross section of the reinforcing structure 1. [Figure 4] 1 is a diagram illustrating the behavior of reinforced structure 1 during an earthquake. [Figure 5] 1A to 1C are diagrams illustrating a reinforcing method using the reinforcing structure 1. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0014] Fig. 1 is a diagram showing an outline of a reinforcement structure 1 for a bridge pier 2 according to an embodiment of the present invention. Fig. 1(a) is a diagram showing a cross section of the bridge pier 2 in the width direction, and Fig. 1(b) is a diagram showing the reinforcement structure 1 as seen from above.

[0015] The reinforcing structure 1 reinforces the base of an existing bridge pier 2, and is provided for the purpose of improving the bending strength of the base.

[0016] The pier 2 is a concrete column member placed on the base slab 3, and has reinforcing bars (not shown) such as main reinforcement bars provided inside. The base slab 3 is a concrete plate-like member, and also has reinforcing bars (not shown) provided inside. The planes of the pier 2 and base slab 3 are rectangular, and the pier 2 has a hollow portion 20 in the center of the plane.

[0017] The reinforcing structure 1 includes concrete 11 provided on the outer periphery of the pier 2, main reinforcing bars 12 arranged within the concrete 11, anchor steel bars 13 connecting the concrete 11 to the base plate 3, and horizontal steel bars 14 connecting the pier 2 to the concrete 11.

[0018] FIG. 2 is a diagram showing the details of the reinforcement structure 1, and shows a cross section of the pier 2 in the width direction of the reinforcement structure 1.

[0019] Concrete 11 is provided on the outer periphery of pier 2 on top of base slab 3. The bottom 11a of concrete 11 is wider than its upper part 11b. Ordinary concrete is used for concrete 11, but high-strength concrete can also be used for bottom 11a. In addition, it is possible to create irregularities at the interface between pier 2 / base slab 3 and bottom 11a of concrete 11 by chipping the surface of pier 2 or by performing surface treatment on base slab 3.

[0020] The main reinforcing bars 12 are reinforcing bars arranged vertically in the concrete 11 from the bottom part 11a to the upper part 11b of the concrete 11, and large-diameter reinforcing bars, for example, SD490, are used. The main reinforcing bars 12 are arranged near the piers 2, and their lower ends are bent outward and fixed into the bottom part 11a of the concrete 11. If the lower ends of the main reinforcing bars 12 were to be fixed to the base slab 3, this would pose problems from the perspective of construction, such as the need to make large-diameter holes in the base slab 3 where reinforcing bars (not shown) are densely packed.

[0021] The anchor rebars 13 are vertical rebars that are embedded in the bottom 11a of the concrete 11. The lower ends of the anchor rebars 13 are inserted into holes 32 that are provided between the reinforcing bars of the base slab 3. The holes 32 are filled with a filler such as epoxy resin or cement, thereby fixing the lower ends of the anchor rebars 13 to the base slab 3. Reinforcing bars with a smaller diameter than the main reinforcing bars 12, such as SD345, are used as the anchor rebars 13, and workability is improved by preventing interference with the reinforcing bars of the base slab 3.

[0022] The horizontal reinforcing bars 14 are reinforcing bars that protrude horizontally outward from the pier 2 along the width direction of the pier 2, and one end is inserted into a hole 22 provided in the side of the pier 2. A filler such as epoxy resin or cement is filled into the hole 22, thereby fixing one end of the horizontal reinforcing bar 14 to the pier 2. The portion of the horizontal reinforcing bar 14 outside the end is buried in the bottom 11a of the concrete 11. The horizontal reinforcing bars 14 may also be configured as multiple separate reinforcing bars (for example, two) connected by a lap joint or the like. This makes it easier to adjust the height of the horizontal reinforcing bars 14, and is preferable in cases where the hole 22 cannot be drilled accurately from the existing reinforcement position in the pier 2.

[0023] Horizontal reinforcing bars 15 are also buried in the bottom 11a in a direction (circumferential direction of the pier 2) perpendicular to the horizontal reinforcing bars 14 in a plan view. The horizontal reinforcing bars 15 are arranged in multiple rows at intervals in the width direction of the pier 2.

[0024] Fig. 3 is a diagram showing a horizontal cross section taken along line aa in Fig. 2. As shown in Fig. 3, a plurality of horizontal reinforcing bars 14 are arranged at intervals in a direction perpendicular to the horizontal reinforcing bars 14 in a plan view (corresponding to the up-and-down direction in Fig. 3). A plurality of main reinforcing bars 12 and anchor reinforcing bars 13 are also arranged at intervals in the above direction.

[0025] In the width direction of the pier 2 (corresponding to the left-right direction in Fig. 3), the main reinforcing bars 12 are arranged in one row, and the anchor reinforcing bars 13 are arranged in multiple rows (nine rows in the example shown). The spacing between the anchor reinforcing bars 13 in the width direction of the pier 2 is small near the pier 2 and large outside, but is not limited to this. However, it is structurally preferable to arrange the anchor reinforcing bars 13 in a position close to the main reinforcing bars 12.

[0026] 2, in this embodiment, a T-shaped fixing portion 131 that is wider than the anchor rebar 13 is provided at the upper end of the anchor rebar 13. The fixing portion 131 is arranged so as to engage with the horizontal rebars 14, 15 from above at the intersection of the horizontal rebars 14, 15.

[0027] As shown in Figure 4(a), the reinforcing structure 1 of this embodiment is designed so that when an earthquake or the like occurs, the tensile force P generated in the main reinforcing bars 12 due to bending M of the pier 2 is transmitted into the bottom 11a of the concrete 11 by anchoring the main reinforcing bars 12 to the bottom 11a, and the tensile force P is distributed and transmitted to the base slab 3 by multiple stages of anchor steel bars 13.

[0028] Furthermore, because the upper end of the anchor rebar 13 is T-shaped with the anchoring part 131, cone-shaped failure, in which the part above the dotted line Q of the bottom 11a of the concrete 11 is pulled out by the tensile force P of the main reinforcing bars 12, is suppressed. In particular, the outer anchor rebars 13, which have a short anchoring length to this part, also effectively resist cone-shaped failure, in which this part is pulled out by the tensile force P, and contribute to suppressing cone-shaped failure.

[0029] In the event of a larger earthquake, as shown in Figure 4(b), the main reinforcing bars 12 will yield between the bottom 11a of the concrete 11 and its upper part 11b, and no further tensile force will act on the bottom 11a, causing the anchor steel bars 13 and other elements within the bottom 11a to behave elastically.

[0030] FIG. 5 is a diagram illustrating a method for reinforcing an existing bridge pier 2 with a reinforcing structure 1. As shown in FIG.

[0031] In this embodiment, first, as shown in FIG. 5(a), one end of the horizontal reinforcing bar 14 is fixed to the pier 2, and the horizontal reinforcing bar 14 is arranged. Then, as shown in FIG. 5(b), the main reinforcing bars 12, anchor reinforcing bars 13, horizontal reinforcing bars 15, etc. are arranged around the periphery of the pier 2, and a formwork (not shown) for pouring concrete 11 is placed. By pouring concrete 11 into the formwork, the reinforcing structure 1 shown in FIG. 2 is formed, thereby reinforcing the existing pier 2. As mentioned above, the horizontal reinforcing bar 14 may also be composed of two separate reinforcing bars. In this case, the reinforcing bar on the pier 2 side is inserted into the hole 22 and fixed to the pier 2, and then the outer reinforcing bar is installed. Furthermore, before installing the outer reinforcing bar, the outermost anchor reinforcing bar 13 is installed. Note that this anchor reinforcing bar 13 does not have an anchoring portion 131.

[0032] As explained above, according to this embodiment, concrete 11 is provided on the outer periphery of an existing pier 2, the main reinforcing bars 12 are embedded in the concrete 11 and fixed into the bottom 11a of the concrete 11, and the bottom 11a of the concrete 11 is fixed to the base slab 3 by anchor steel bars 13, thereby reinforcing the existing pier 2. In particular, since anchoring parts 131 are provided at the upper ends of the anchor steel bars 13, when a tensile force P acts on the main reinforcing bars 12 in conjunction with bending M of the pier 2, the tensile force P is prevented from causing cone-shaped fracture in the bottom 11a of the concrete 11, improving the bearing capacity.

[0033] In this embodiment, the horizontal reinforcing bars 14 connect and integrate the pier 2 and the concrete 11, preventing them from separating during an earthquake, etc. Furthermore, by locking the fixing parts 131 of the anchor reinforcing bars 13 to the horizontal reinforcing bars 14, the arrangement of the anchor reinforcing bars 13 becomes easier.

[0034] Furthermore, in this embodiment, the tensile force P generated in the main reinforcing bars 12 during an earthquake or the like is transmitted into the bottom 11a by the main reinforcing bars 12 being fixed to the bottom 11a of the concrete 11, and the tensile force P is transmitted in a dispersed manner to the base slab 3 by the multiple stages of anchor rebars 13. Therefore, rebars with lower strength than the main reinforcing bars 12 can be used as the anchor rebars 13; for example, using anchor rebars 13 with a small diameter makes it easier to install the anchor rebars 13 in the base slab 3. Furthermore, the anchor rebars 13 are often arranged at a pitch of about 300 mm (the spacing in the vertical direction in FIG. 3 ), and even when the main reinforcing bars 12 are arranged at a pitch of 150 mm, it becomes necessary to arrange the anchor rebars 13 in a dispersed manner in multiple stages as described above.

[0035] However, the present invention is not limited to the above-described embodiments. For example, the fixing portion 131 of the anchor rebar 13 is not limited to the one that widens in a T-shape. For example, the upper end of the anchor rebar 13 may be bent into a hook shape to form the fixing portion 131, and the bent portion in the hook shape may be engaged with the horizontal rebar 14 or the like.

[0036] The arrangement of the main reinforcing bars 12 and anchor reinforcing bars 13 is not limited to the above, and it is sufficient if the anchor reinforcing bars 13 are arranged in more stages than the main reinforcing bars 12 in the width direction of the pier 2. It is also possible to omit the horizontal reinforcing bars 14. Furthermore, from the perspective of earthquake-resistant design, it is desirable to arrange high-strength reinforcing bars such as SD490 as the main reinforcing bars 12 (because the number of reinforcing bars arranged can be reduced), but from the perspective of construction experience, etc., ordinary reinforcing bars such as SD345 may be used instead of high-strength reinforcing bars.

[0037] Furthermore, there are no particular limitations on the shapes, configurations, etc. of the piers 2 and the foundation slab 3. For example, the piers 2 are not limited to those having a rectangular planar surface with a hollow portion 20, but may also have a circular planar surface, or may not have a hollow portion 20. Furthermore, the application of the reinforcement structure 1 is not limited to the piers 2, and the reinforcement structure 1 can be applied to reinforce various types of column members.

[0038] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that those skilled in the art can conceive of various modifications or alterations within the scope of the technical ideas disclosed herein, and it is understood that these modifications also fall within the technical scope of the present invention. [Explanation of symbols]

[0039] 1: Reinforcement structure 2: Bridge pier 3: Basic version 11: Concrete 11a: Bottom 11b: Upper part 12: Main reinforcement bars 13: Anchor rebar 14, 15: Horizontal rebar 131: Fixing section

Claims

1. A reinforcement structure for an existing column member installed on a foundation slab, Concrete provided on the outer periphery of the column member on the base plate so that the bottom portion expands outward relative to the upper portion thereof; A reinforcing bar is arranged vertically in the concrete from the bottom to the upper part of the concrete, and a lower end of the reinforcing bar is fixed in the bottom of the concrete. An anchor rebar whose lower end is fixed to the base plate and embedded in the bottom of the concrete; and An anchoring portion is provided at the upper end of the anchor rebar, Horizontal reinforcing bars protruding from the column members are embedded in the bottom of the concrete, A reinforced structure characterized in that the anchoring portion is arranged to engage with the horizontal reinforcing bar.

2. A method for reinforcing an existing pillar member using the reinforcing structure according to claim 1, A step of arranging the reinforcing main bars and the anchor reinforcing bars at the outer periphery of the column member; Pouring the concrete on the outer periphery of the pillar member; A reinforcing method comprising the steps of:

Images