JP7186078B2 - Reinforcement structure and reinforcement method for masonry structure - Google Patents

Description

The present invention relates to a reinforcement structure and a method for reinforcing a masonry structure, for example, reinforcement of an existing masonry structure such as a brick wall for seismic reinforcement by providing PC steel bars or the like. It relates to structure and reinforcement method.

Conventionally, in seismic reinforcement of existing brick (masonry) buildings, a hole is dug vertically from the top of the brick wall, and after inserting a PC steel rod into the hole, the end is fixed and prestress is introduced. There is known a construction method for improving the structural performance of a brick wall by doing so (see Patent Documents 1 and 2, for example). In this construction method, a vertical hole is made to penetrate to the bottom of the concrete of the brick wall or its foundation, and a fixing plate is provided under the foundation to fix the PC steel rod, so the construction takes a lot of time and effort.

As a method to solve this problem, the vertical hole does not penetrate below the brick wall or concrete foundation. A method has been developed in which a fixing plate is attached to the part to fix it, and a method in which a vertical hole with a larger diameter is dug from the horizontal hole and a fixing plate is attached in it. Since the fixing plate used is larger than the vertical hole in order to fix the tensile force of the PC steel bar to the existing frame, a large horizontal hole was required for installation.

JP 2010-281033 A JP-A-11-324341

The above-mentioned conventional construction method requires a large horizontal hole to be made in the side, which takes a lot of time and effort, and may affect the appearance of the building and damage its cultural property value. Therefore, there is a need for a reinforcement technique that can minimize the impact on the appearance of the building without taking much time.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a reinforcing structure and a reinforcing method for a masonry structure that can reduce the influence on the appearance of the masonry structure. .

In order to solve the above-described problems and achieve the object, the reinforcing structure for masonry structure according to the present invention is a structure for reinforcing an existing masonry structure formed by stacking masonry materials, Non-penetrating vertical holes from the top of the masonry structure to the bottom of the masonry structure or inside its foundation, and the bottom of the vertical hole or below the bottom end and larger than the hole diameter of the vertical hole a diameter-expanded hole, a rod-shaped member inserted through the vertical hole and functioning as a tendon or a reinforcing member, a fixing plate fixed to the lower end of the rod-shaped member and arranged in the diameter-expanded hole, and an expanded-diameter hole and a solidifying material filled in the space and embedding the fixing plate, and a distance for forming a compression strut is provided between the fixing plate and the upper part of the enlarged diameter hole.

Further, a method for reinforcing a masonry structure according to the present invention is a method for reinforcing an existing masonry structure formed by stacking masonry materials, wherein the masonry structure is reinforced from the top of the masonry structure. drilling a non-penetrating vertical hole through the bottom of the object or into its foundation; and drilling an enlarged hole larger than the diameter of the vertical hole below the bottom or bottom end of the vertical hole. a step of fixing a fixing plate to the lower end of a rod-shaped member that functions as a tendon or a reinforcing member, and then inserting and arranging the bar-shaped member through the vertical hole and arranging the fixing plate in the enlarged diameter hole; filling the solidifying material and burying the fixing plate.

Another method for reinforcing a masonry structure according to the present invention is that in the above-described invention, the rod-shaped material functions as a tendon, and the rod-shaped material has a lower end as a fixed end and an upper end as a tension end. The method further comprises the step of applying tension to the material to apply a vertical compressive force to the masonry structure.

According to the reinforcement structure for a masonry structure according to the present invention, it is a structure for reinforcing an existing masonry structure formed by piling up masonry materials, and the masonry structure is A non-penetrating vertical hole provided to the bottom of an object or the inside of its foundation, an enlarged diameter hole provided at the bottom or below the bottom end of the vertical hole and having a diameter larger than the diameter of the vertical hole, and a vertical hole A rod-shaped member that is inserted and arranged to function as a tendon or a reinforcing member, a fixing plate that is fixed to the lower end of the rod-shaped member and arranged in the enlarged diameter hole, and a solidifying material that fills the enlarged diameter hole and embeds the fixing plate. A space is provided between the fixing plate and the upper part of the enlarged diameter hole for forming a compression strut, so the fixing plate can be constructed only from above without drilling a horizontal hole on the side. . Since no hole is formed in the side surface, there is an effect that the effect on the appearance of the masonry structure can be reduced.

Further, according to the method for reinforcing a masonry structure according to the present invention, a method for reinforcing an existing masonry structure formed by piling up masonry materials, wherein the masonry is applied from the top of the masonry structure. drilling a non-penetrating vertical hole through the bottom of the structural structure or into its foundation; and drilling an enlarged hole with a diameter greater than the diameter of the vertical hole at the bottom or below the bottom edge of the vertical hole. and after fixing the fixing plate to the lower end of the bar-shaped member functioning as a tendon or reinforcing member, inserting the bar-shaped member through the vertical hole and placing the fixing plate in the enlarged diameter hole; Since the step of filling the hole with the solidifying material and burying the fixing plate is provided, the fixing plate can be constructed only from above without making a horizontal hole in the side surface. Since no hole is formed in the side surface, there is an effect that the effect on the appearance of the masonry structure can be suppressed.

According to another method of reinforcing a masonry structure according to the present invention, the rod-shaped material functions as a tendon, and the rod-shaped material is tensioned with the lower end of the rod-shaped material as a fixed end and the upper end as a tension end. Since the step of applying a force to apply a compressive force in the vertical direction to the masonry structure is further provided, when the compressive force is applied to the masonry structure, the effect on the appearance of the masonry structure is reduced. There is an effect that it is possible to provide a reinforcing method that can be kept small.

FIG. 1 is a front sectional view showing an embodiment of a reinforcement structure and a reinforcement method for a masonry structure according to the present invention. FIG. 2 is a diagram showing another embodiment of the vertical hole enlarged diameter portion. 3A and 3B are diagrams showing modifications of the enlarged diameter portion of the vertical hole, where (1) is modification 1, (2) is modification 2, (3) is modification 3, and (4) is modification 4. be. FIG. 4 is a model diagram of analysis performed to verify the effect of the present invention, (1) is a comparative example, and (2) is an example. FIG. 5 is a graph showing analysis results.

Embodiments of a reinforcement structure and a reinforcement method for a masonry structure according to the present invention will be described in detail below with reference to the drawings. In addition, this invention is not limited by this embodiment.

In this embodiment, a brick wall 10 as shown in FIG. 1 will be described as an example of a masonry structure to be reinforced. The brick wall 10 is a wall formed by piling up bricks 12 as masonry material, and is constructed on a concrete foundation (not shown) provided in the ground. The brick 12 is a rectangular parallelepiped building material made by baking or compressing clay, shale, and mud. Joints 14 made of mortar, grout, or the like are provided between vertically and horizontally adjacent bricks 12 . The masonry structure of the present invention is not limited to a brick wall, and may be, for example, a concrete wall in which concrete blocks are piled up as masonry material, or a wall in which stone materials are piled up as masonry material.

In addition, in the present embodiment, a case where the bar-shaped material is a PC steel bar (strand) will be described as an example, but the bar-shaped material of the present invention is not limited to this. For example, prestressing tendons such as PC steel wires, FRP stranded wires, and rods may be used, and reinforcing materials such as reinforcing bars may be used.

The reinforcing method of the present embodiment is carried out in steps 1-6. The construction details of each step are described below.

(Step 1)
First, as shown in FIG. 1 , a vertical hole 16 (hereinafter referred to as “general vertical hole portion”) is drilled inside the brick wall 10 for passing the PC steel rod in the vertical direction. The vertical hole general portion 16 is a non-through hole with a circular cross section that extends vertically downward from the upper end 18 (top) of the brick wall 10 . The vertical hole general portion 16 does not penetrate to the bottom of the brick wall 10 or the concrete foundation (not shown), but is drilled to the position where the lower part of the brick wall 10 or the lower part of the PC steel rod 20 in the concrete foundation is fixed. The hole diameter D1 of the vertical hole general portion 16 is set slightly larger than the diameter or the maximum dimension D3 of the fixing plate 22 fixed to the PC steel rod 20, as will be described later. Although not shown, a plurality of vertical hole general portions 16 are formed along the length direction of the brick wall 10 at intervals.

(Step 2)
Next, the horizontal outer side of the lower end of the vertical hole general portion 16 is cut, and the diameter of the lower end is enlarged larger than the diameter of the vertical hole general portion 16 . As a result, a vertical hole enlarged diameter portion 24 (diameter enlarged hole) having an enlarged diameter is formed at the lower end portion of the vertical hole general portion 16 . The enlarged diameter portion 24 of the vertical hole is a cylindrical cavity coaxial with the axis of the hole of the general vertical hole portion 16 .

(Step 3)
Next, after attaching the fixing plate 22 to the lower end portion of the PC steel rod 20 , the PC steel rod 20 is inserted from the upper end 18 of the brick wall 10 into the vertical hole general portion 16 . The size and shape of the fixing plate 22 are set to be smaller than the diameter D1 of the vertical hole general portion 16 and to be inserted from the upper end 18 of the vertical hole general portion 16 as described above. That is, it is set so as to satisfy the following relational expression.

D3 ≤ D1 ≤ D2 Expression (1)
Here, D1: diameter of the vertical hole general portion 16
D2: Diameter of vertical hole enlarged diameter portion 24
D3: diameter or maximum dimension of fixing plate 22

Note that the fixing plate of the present invention is not limited to this, and may be any one that adds a fixing head to a bar-like material such as a PC steel bar. For example, a fixing nut that is screwed onto a PC steel bar may be used.

(Step 4)
Subsequently, the PC steel rod 20 and the fixing plate 22 are inserted to a position where the fixing plate 22 is accommodated in the enlarged diameter portion 24 of the vertical hole. The fixing plate 22 does not contact the upper surface 26 (upper portion) of the vertical hole enlarged diameter portion 24, and a certain vertical distance L can be secured between the upper surface 26 of the vertical hole enlarged diameter portion 24 and the fixing plate 22. preferable. This is because a compression strut (bundle) S is formed between the fixing plate 22 and the upper surface 26 of the enlarged diameter portion 24 of the vertical hole to transmit the fixing force. However, if the angle of the compression strut S is close to horizontal, the transmission efficiency will be poor.

(D2−D3)/2≦L Expression (2)
Here, D1 to D3:
L: Vertical distance between the fixing plate 22 and the upper surface 26 of the vertical hole enlarged diameter portion 24

The PC steel rod 20 and the fixing plate 22 may be in contact with the lower surface 28 of the vertical hole enlarged diameter portion 24, or may be separated as in the example of FIG.

(Step 5)
Next, the vertical hole enlarged diameter portion 24 is filled with a solidifying material 30 such as mortar. Although the vertical hole general portion 16 may or may not be filled, the vertical hole enlarged diameter portion 24 is always filled. It is desirable that the solidifying material 30 such as mortar has a higher compressive strength than the existing brick wall 10 .

(Step 6)
Next, after the solidifying material 30 is solidified, tension is applied to the PC steel bar 20 with the lower end of the PC steel bar 20 as the fixed end and the upper end as the tensioning end. It is fixed to a fixing plate (not shown) provided at 18 or the like. As a result, a compressive force in the vertical direction is applied between the upper end 18 of the brick wall 10 and the lower fixing plate 22 to reinforce the brick wall 10, thereby reinforcing the masonry structure 100 according to the present embodiment. can be obtained.

According to this reinforcement method, in the reinforcement method of the brick wall 10 in which the PC steel rod 20 is inserted in the vertical direction, the bottom wall having a large fixing strength can be obtained only by drilling from above without drilling from the side. A side fixing portion can be formed. Therefore, little amount of excavation is generated.

Moreover, since no horizontal hole is formed in the side surface of the brick wall 10, the external appearance of the brick wall 10 is little or almost not affected. Therefore, according to the present embodiment, it is possible to reinforce the brick wall 10 with relatively little effort, while minimizing the impact on the appearance. Therefore, it is possible to prevent the value of the brick wall 10 from deteriorating as a cultural asset.

Moreover, even when the fixing portion is provided at a position lower than the ground, it is not necessary to excavate the ground in order to make a hole in the side surface.

In the above-described embodiment, the case where the vertical hole enlarged diameter portion 24 (diameter enlarged hole) is a cylindrical cavity has been described as an example, but the present invention is not limited to this. For example, as shown in FIG. 2, in order to increase the fixing force, the vertical hole enlarged diameter portion 24A may have a shape in which a truncated cone, a cylinder, and an inverted truncated cone are combined vertically. By doing so, it is possible to perform fixation with greater rigidity and durability.

Moreover, the vertical hole enlarged diameter part 24 (diameter enlarged hole) can adopt various shapes other than the above. For example, a truncated cone-shaped vertical hole enlarged diameter portion 24B as shown in FIG. 3(1), an inverted truncated cone-shaped vertical hole enlarged diameter portion 24C shown in FIG. A vertical hole enlarged diameter portion 24D, and a vertical hole enlarged diameter portion 24E having a shape in which a truncated cone and an inverted truncated cone are vertically combined as shown in (4), and the like are included.

(Verification of effects of the present invention)
FEM analysis was performed to verify the effects of the present invention. The contents and results will be described below.

An analysis model as shown in FIG. 4 was used for the FEM analysis. This analysis model is a model for reinforcing a concrete wall in which concrete blocks 1 are piled up as a masonry material. In the analysis model of the comparative example, as shown in FIG. 4(1), a steel rod 4 having a fixing plate 3 was inserted into a linear vertical hole 2 and arranged. In the analysis model of the embodiment of the present invention, as shown in FIG. 4(2), an enlarged diameter hole 5 is provided at the bottom of a linear vertical hole 2, and a steel rod 4 is inserted into the vertical hole 2 and expanded. A fixing plate 3 is arranged in the diameter hole 5 . In both the comparative example and the working example, the grout 6 was filled in the vertical hole and the enlarged diameter hole. Axisymmetric FEM analysis for pulling out a steel bar was performed for each model that was axially symmetrical about the rotation axis Z, and the yield strength improvement effect by fixing the enlarged diameter hole was verified.

FIG. 5 shows the relation between the load when the steel bar is pulled out and the displacement of the steel bar obtained by the analysis. As shown in this figure, the comparative example (without enlarged diameter hole) breaks due to slippage at the interface between the concrete and the grout. On the other hand, in the example (with enlarged diameter hole), even if the fixing plate is small, a compression strut is formed from the fixing plate to the concrete, so it can be seen that a large fixing strength is exhibited. Therefore, according to the present invention, it can be expected that the fixing of the expanded hole can improve the bearing strength.

INDUSTRIAL APPLICABILITY As described above, according to the reinforcement structure for a masonry structure according to the present invention, it is a structure for reinforcing an existing masonry structure formed by piling up masonry materials. A non-penetrating vertical hole provided from the top to the lower part of the masonry structure or the inside of its foundation, and an enlarged diameter that is provided below the lower part or lower end of the vertical hole and is larger than the hole diameter of the vertical hole a hole, a rod-shaped member inserted through the vertical hole and functioning as a tendon or a reinforcing member, a fixing plate fixed to the lower end of the rod-shaped member and arranged in the expanded hole, and a fixing plate filled in the expanded hole and a solidifying material for embedding the fixing plate, and a distance for forming a compression strut is provided between the fixing plate and the upper part of the enlarged diameter hole. construction becomes possible. Since no holes are made in the side surfaces, the effect on the appearance of the masonry structure can be kept small.

Further, according to the method for reinforcing a masonry structure according to the present invention, a method for reinforcing an existing masonry structure formed by piling up masonry materials, wherein the masonry is applied from the top of the masonry structure. drilling a non-penetrating vertical hole through the bottom of the structural structure or into its foundation; and drilling an enlarged hole with a diameter greater than the diameter of the vertical hole at the bottom or below the bottom edge of the vertical hole. and after fixing the fixing plate to the lower end of the bar-shaped member functioning as a tendon or reinforcing member, inserting the bar-shaped member through the vertical hole and placing the fixing plate in the enlarged diameter hole; Since the step of filling the hole with the solidifying material and burying the fixing plate is provided, the fixing plate can be constructed only from above without making a horizontal hole in the side surface. Since no holes are made in the side surfaces, the effect on the appearance of the masonry structure can be kept small.

According to another method of reinforcing a masonry structure according to the present invention, the rod-shaped material functions as a tendon, and the rod-shaped material is tensioned with the lower end of the rod-shaped material as a fixed end and the upper end as a tension end. Since the step of applying a force to apply a compressive force in the vertical direction to the masonry structure is further provided, when the compressive force is applied to the masonry structure, the effect on the appearance of the masonry structure is reduced. It is possible to provide a reinforcement method that can be kept small.

As described above, the reinforcement structure and reinforcement method for a masonry structure according to the present invention provide an anti-earthquake structure by introducing prestress to an existing masonry structure, such as a brick wall, using PC steel bars or the like. Reinforcing or inserting rebars into an existing masonry structure to reinforce it, it is useful for construction without the need for labor. It is suitable for seismic reinforcement by suppressing the impact to a small extent.

10 brick wall (masonry structure)
12 Brick (masonry material)
14 joint 16 vertical hole general part (vertical hole)
18 upper end (top)
20 PC steel bar (bar-shaped material)
22 fixing plate 24 vertical hole enlarged diameter portion (diameter enlarged hole)
26 upper surface 28 lower surface 30 solidifying material 100 reinforcement structure of masonry structure

Claims (3)

A structure that reinforces an existing masonry structure made by stacking masonry materials,
Non-penetrating vertical holes from the top of the masonry structure to the bottom of the masonry structure or inside its foundation, and the bottom of the vertical hole or below the bottom end and larger than the hole diameter of the vertical hole a diameter-expanded hole, a rod-shaped member inserted through the vertical hole and functioning as a tendon or a reinforcing member, a fixing plate fixed to the lower end of the rod-shaped member and arranged in the diameter-expanded hole, and an expanded-diameter hole The size and shape of the fixing plate are smaller than the hole diameter of the vertical hole, and the size and shape are such that they can be inserted from the upper end of the vertical hole. A reinforcing structure for a masonry structure, characterized in that a distance for forming a compression strut is provided between the upper part of the diameter hole and the upper part of the hole. A method for reinforcing an existing masonry structure comprising stacked masonry materials, comprising:
drilling a blind vertical hole from the top of the masonry structure to the bottom of the masonry structure or into its foundation;
drilling and forming an enlarged diameter hole having a diameter larger than the hole diameter of the vertical hole at the lower part of the vertical hole or below the lower end;
A fixing plate smaller than the hole diameter of the vertical hole and having a size and shape that can be inserted from the upper end of the vertical hole is fixed to the lower end of the rod-shaped material that functions as a tendon or reinforcing material, and then the rod-shaped material is inserted into the vertical hole. and placing the fixing plate in the enlarged diameter hole;
A method of reinforcing a masonry structure, comprising the step of filling a hardening material into the enlarged diameter hole and burying the fixing plate. The rod-shaped material functions as a tendon, and the lower end of the rod-shaped material is a fixed end and the upper end of the rod-shaped material is a tension end to apply a tension force to the rod-shaped material to apply a vertical compressive force to the masonry structure. 3. The method of reinforcing a masonry structure according to claim 2, further comprising:

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