KR101858556B1 - Seismic retrofit system improving horizontal resistance and shear deforming performance using high-ductile precast concrete - Google Patents

Abstract

The present invention relates to a seismic retrofit system of a building for improving horizontal resistance and shear deforming performance using high-ductile precast concrete, in which a seismic force is transmitted to high-ductile concrete so that the high-ductile concrete can be subject to shear resistance, both ends of the high-ductile concrete are compactly wrapped and supported while being easily bonded to other members, and it is possible to prevent a collapse and breakage of the end of the high-ductile concrete during the transmission of the seismic force, thereby reinforcing internal strength and strain-resistance. The present invention includes: a high-ductile PC part (10) including a high-ductile composite (11) and a reinforcing bar (12) installed inside the high-ductile composite (11), in which the high-ductile composite (11) exhibits the direct tensile strain of 1.5% or more, causes a strain hardening behavior in which the stress is increased together with the strain without the decrease of the stress even when the initial crack occurs under the action of bending and tensile load, and exhibits a multiple crack property showing numerous and homogeneous micro-cracks; upper and lower anchoring portions (20A, 20B) installed at upper and lower ends of the high-ductile PC part (10) while being partially buried in the high-ductile composite (11) in a state in which the upper and lower anchoring portions (20A, 20B) are joined with at least a part of the reinforcing bar (12); and upper and lower connection portions (30A, 30B), one end of which is coupled to the upper or lower anchoring portions (20A, 20B) and the other end is coupled to an existing building.

Description

TECHNICAL FIELD [0001] The present invention relates to a seismic reinforcement system for a building having improved horizontal resistance and shear deformation performance by using a tough precast concrete,

The present invention relates to an earthquake-resistant reinforcement system for a building having improved horizontal resistance and shear deformation performance by using tough precast concrete, and more particularly, to an earthquake-resistant reinforcement system in which seismic force is transmitted to high- , It is possible to improve the bonding property with other members while supporting both ends of the tough concrete in a compact manner while supporting the same, and it is possible to prevent the collapse and breakage of the end of the tough concrete at the transmission of the seismic force, The present invention relates to an earthquake-proof reinforcement system for a building.

The seismic strengthening method is a method for reinforcing a structure to withstand a horizontal earthquake load. It is a method for minimizing the expected damage at a minimum cost when it is judged that the seismic performance of a building to resist an earthquake is insufficient. For earthquake-proof reinforcement of buildings, concrete reinforcement work is being carried out after ① clearly predicting how the building will move during an earthquake while satisfying conditions such as ① prevention of collapse ② maintenance of function after earthquake ③ preservation of asset value of building.

These earthquake-proof reinforcement are: (1) Buildings constructed by the former Design Law, (2) Insufficient earthquake resistance, (2) New seismic performance enhancement is required to increase or reduce buildings, or (3) Reinforce and reuse damaged structures. And the horizontal strength and ductility capacity in seismic design are the most important factors that dominate the seismic performance of the building. Therefore, the basic concept in seismic strengthening of buildings with low seismic performance is to increase the building strength Or (2) to improve the deformability of buildings, or (3) to mix (1) and (2).

The basic concept can be expressed as strength enhancement type, softening enhancement type, and energy dissipation type. Strengthening type is a method to increase the strength and stiffness of a building. It can be divided into extension of columns and beams, extension of shear walls, and installation of braced frames. In addition, ductility enhancement type is a method to improve the deformability of the building (prevention of sudden collapse). It can be divided into reinforcing of steel sheets of pillars and beams, reinforcing of carbon fiber sheets of columns and beams, and prestressing of pillars and beams. In addition, the energy dissipation type is a method of reducing earthquake load acting on a building by absorbing earthquake energy, and can be divided into a friction type, a metal yield type, and a hydraulic cylinder type.

Among the various types of seismic retrofitting structures, a conventional technique of increasing the strength of a building by increasing the cross section of columns and beams is disclosed in Korean Registered Patent No. 10-1070043 (Registered on September 27, 2011, Type damper, hereinafter referred to as " prior art ").

The above-mentioned prior art discloses a column structure 1 which is installed in a pillar shape between reinforcing steel sheets and a strain-hardening cement composite material in which 1.5 to 3.5 volume parts of fibers are added to 100 volume parts of cement paste or cement mortar; A reinforcing portion (2) connecting the column structure and the slab; And a plurality of bolts (3) for fixing the reinforcing portion to the column structure and the slab, respectively, so as to resist a compressive lateral force greater than a design value applied to a building during an earthquake, So as to exhibit significantly improved seismic performance against buildings.

However, in this conventional technique, the STAB is made of reinforced concrete (RC), so that its size becomes very large in order to exhibit high stiffness and strength, and there is a disadvantage that installation is inefficient. When the seismic force (horizontal load) It is difficult to exert a reinforcing effect to sufficient strength and deformation amount.

In addition, in the prior art, since the column structure and the reinforcing portion are only connected by the bolts, it is difficult for the hydrodynamic load to be sufficiently transferred to the column structure, so that the column structure can not exhibit the energy dissipation and damage control ability There was a problem.

KR 10-1070043 B1

It is an object of the present invention to provide an earthquake-proof reinforcement system for a building that allows seismic force to be transmitted to the high-tensile concrete so that the high-tensile concrete can be sheared.

It is another object of the present invention to provide an earthquake-proof reinforcement system for a building that can compactly wrap and support both ends of the tough concrete while improving bonding with other members.

It is still another object of the present invention to provide an earthquake-proof reinforcement system for a building that can prevent collapse and breakage of a tough concrete end portion when a seismic force is transmitted, and can exhibit reinforcement effect to a greater strength and deformation amount.

According to an aspect of the present invention, there is provided an earthquake-resistant reinforcement system for a building. The earthquake-reinforcement system of the present invention is characterized by having a direct tensile strain of 1.5% or more and, after bending and tensile load, Which is characterized in that it exhibits a strain hardening behavior in which stress is increased with an increase in strain without deteriorating the tensile strength of the steel sheet and exhibits a multiple crack characteristic in which microcracks are homogeneous and numerous and a reinforcing bar Toughness PC part; An upper and a lower fixing unit installed at upper and lower ends of the high toughness PC unit, respectively, while partially embedded in the high toughness composite in a state of being coupled with at least part of the reinforcing bars; And upper and lower connection portions, one end of which is coupled to the upper or lower fixing portion and the other end is coupled to the existing building.

The reinforcing bars include vertical roots, horizontal roots and diagonal roots, and both ends of the roots are coupled to the upper or lower connecting portions, and both ends of the diagonal roots are coupled to one side of the upper or lower fixing portion .

The fusing unit may include a reinforcing plate vertically installed at the connecting portion and coupled with the diagonal frame to the side, and a stiffener vertically installed at the connecting portion and the reinforcing plate to reinforce the reinforcing plate.

The diagonal roots are arranged in the first diagonal direction and the second diagonal direction, respectively, and the diagonal roots arranged in the respective directions are joined to the different side surfaces of the reinforcing plate.

The reinforcement rods further include a stone runout having both ends joined to the stiffening plate or stiffener and an interruption extending toward the tough composite and being embedded in the toughenable composite.

In addition, a fiber sheet may be wrapped and reinforced at the upper and lower ends of the tough PC section exposed from the upper and lower fusing sections to prevent collapse and destruction at both ends of the tough PC section.

At this time, it is preferable that the fiber sheet is wrapped with a width corresponding to a length equal to or longer than a long side length in a transverse cross section of the tough PC portion.

According to the seismic retrofitting system of a building having improved horizontal resistance and shear deformation performance by using the tough precast concrete according to the present invention, diagonal roots are arranged inside the tough concrete, and the diagonal roots are fixed to be straight without bending And the seismic force is transmitted directly to the diagonal roots, so that the tough concrete can have a shear resistance against an earthquake.

According to the present invention, it is possible to provide a compact structure by disposing a connecting portion, which is a steel member, at both ends of the tough concrete, and to improve the bonding property with other members.

According to the present invention, the upper and lower ends of the high-tensile concrete are wrapped and reinforced with a fiber sheet to prevent the collapse and destruction of the end of the high-tensile concrete, and the reinforcing effect of the high- .

According to the present invention, by providing a fixing part (a composite part of a steel frame and a tough RC) having a high strength and stiffness between the tough concrete and the connecting part, it is possible to induce the tough concrete to be damaged first in case of an earthquake, (Brittle fracture), and it is possible to absorb earthquake energy in this process and to minimize earthquake damage of buildings.

In addition, according to the present invention, since stone run-out is additionally disposed inside the tough concrete and the stone run-out is exposed to a certain height in the tough concrete in a state where the stone work is attached to the fusing unit, It is possible to prevent shear failure due to horizontal force and to prevent pull-out failure due to the rotational force of the tough concrete. Thus, the tough concrete can provide sufficient shear resistance against the seismic force.

In addition, according to the present invention, it is possible to install and pass a door after reinforcement, and to minimize the amount of demolition and damage to existing buildings, And can be installed in a narrow indoor / outdoor space.

1 is a view showing a configuration of an earthquake-proof reinforcement system according to the prior art,
2 is a front view showing an anti-seismic reinforcement system according to the present invention,
FIG. 3 is a view showing a reinforcing bar through the tough composite in the seismic strengthening system shown in FIG. 2;
4 is a sectional view taken along the line A-A 'in Fig. 2,
5 is a cross-sectional view taken along the line B-B 'in Fig. 2,
6 and 7 are views showing an anti-seismic reinforcement system installed in an indoor /
8 and 9 are views showing an anti-seismic reinforcement system installed outside / outside the existing building,
10 is a graph showing the results of an experiment on an earthquake-proof performance of an existing RC frame reinforced with an earthquake-proof reinforcement system according to the present invention.

Hereinafter, an earthquake-proof reinforcement system for a building having improved horizontal resistance and shear deformation performance using the tough precast concrete according to the present invention will be described with reference to the accompanying drawings.

FIG. 2 is a front view showing an anti-seismic reinforcement system according to the present invention, FIG. 3 is a view showing a reinforcing bar by looking at a high-toughness composite in the anti-seismic reinforcement system shown in FIG. 2, ', And FIG. 5 is a cross-sectional view taken along the line B-B' in FIG.

The earthquake-proofing system according to the present invention is composed of an upper end connecting portion 30A, an upper end fixing portion 20A, a tough PC portion 10, a lower end fixing portion 20B and a lower end connecting portion 30B, The upper and lower end connection portions 30A and 30B of the anti-seismic reinforcement system according to the present invention are joined (bolted or welded) to the joint member C (steel frame member) provided on the side or bottom surface of the beam B It is a technology that can be done.

The high tenacity PC section 10 is a member that improves the seismic performance of existing buildings by shearing resistance against a horizontal load (seismic force) acting at the time of an earthquake and has a shear aspect ratio (height / width ratio) of 1.5 to 3.5 The shear resistance of the building from the seismic force of small input level to the seismic force of high input level can be effectively increased through the shear resistance.

In addition, the tough PC section 10 according to the present invention uses a tough concrete having a direct tensile strain of 1.5% or more, so that even after the design horizontal stress, unlike ordinary concrete, the large tensile strain of 5% or more without a shear fracture (brittle fracture) (Excellent shear deformation performance). In this process, shear cracks are dispersed to control damages by fine harmless cracks, and seismic energy can be absorbed to minimize earthquake damage of existing buildings.

The high toughness PC portion 10 according to the present invention includes the rigid composite 11 and the reinforcing rope 12.

The tough composite (11) should exhibit a direct tensile strain of 1.5% or more. In addition, the hard-wearing composite 11 according to the present invention exhibits stress-hardening behavior in which the stress is increased with the increase of the strain without decreasing the stress even after the occurrence of the initial crack under the action of the bending and tensile load, A multiple cracking characteristic in which microcracks of 100 탆 or less are homogeneous and numerous occurs should be exhibited.

In order to exhibit these characteristics, the tough composite (11) according to the present invention can be exemplified as being mixed as shown in the following [Table 1].

Materials used   Composition ratio
(Weight ratio) Remarks

dry
Do not know
tar

cement 15 ~ 35  No limitations Mixed material 15 ~ 40  Fly ash, slag, CSA (can mix one or more) magnesia 0.5 to 5  Under-magnesia or sub-magnesia High powder filler 1 to 10  Silica fume, dried red mud (may be mixed with one or more) filler 20 to 50  Calcium carbonate, hollow ceramic balls (can be mixed with one or more) Functional additive 0.1 to 1.0  A thickening agent, a defoaming agent, a surfactant (may be mixed with one or more) (sub Total) 100  The total weight of the material Number of ingredients 18 ~ 30 fiber 15 to 30  High tensile PVA fiber, high tensile PE fiber, high tensile steel fiber ※ The above water content and fiber content are based on 100 parts by weight of dry mortar.

As shown in Table 1, the high-toughness composite 11 contains 15 to 35 wt% of cement, 15 to 40 wt% of an admixture, 0.5 to 5 wt% of magnesia, 1 to 10 wt% of a high- By weight to 50% by weight, and a functional additive in an amount of 0.1 to 1.0% by weight.

More specifically, if the cement is used in an amount of less than 15% by weight, it is difficult to ensure early strength. If the cement is used in an amount of more than 35% by weight, there is a fear of an increase in unit price and an increase in shrinkage . There are no particular restrictions on the materials used for such cement.

The admixture is made by mixing at least one of fly ash, slag and CSA and is used in a range of 15 to 40 wt%. If the admixture is used in an amount less than 15% by weight, the effect of improving long-term strength and improving fluidity is insignificant. If the admixture is used in an amount exceeding 40% by weight, securing of early strength is difficult and the time for removing the formwork is delayed.

Magnesia is used for ensuring the volume stability of the cured product, and under-magnesia or sub-magnesia is used in the range of 0.5 to 5 wt%. If the magnesia is used in an amount of less than 0.5% by weight, the effect of incorporation is insignificant. If the magnesia is used in an amount of more than 5% by weight, the unit cost may increase and overexpansion may occur.

A high-strength filler is used to increase the micropore filling effect and fiber dispersibility, and is used by mixing at least one of silica fume and dried red mud. The high-strength filler is used in an amount of 1 to 10 wt%. If the high-booster filler is used in an amount less than 1% by weight, the effect of the addition is insignificant. If the filler is used in an amount exceeding 10% by weight, the viscosity increases and the working efficiency decreases.

The filler is used for improving the economical efficiency of the cured body and for the workability. It is used by mixing at least one of calcium carbonate and hollow ceramic balls. The filler is used in a range of 20 to 50% by weight. If the filler is used in an amount of less than 20% by weight, the effect of incorporation is small and the amount of the cement and the admixture is increased to increase the unit cost. If the filler is used in excess of 50% by weight, the fiber dispersibility and the working efficiency are lowered.

The functional additive is a mixture of at least one of a fluidizing agent, a thickener, a defoamer, and a surfactant, and is used in a range of 0.1 to 1.0 wt%.

Next, the compounding number is used within a range of 18 to 30 parts by weight relative to 100 parts by weight of the above-mentioned dry mortar.

The fibers are used to inhibit the occurrence of cracks by reducing the crosslinking action of the fibers and reduce the strain of the fibers, and they include at least one of high-tensile PVA fibers, high-tensile PE fibers and high-tensile steel fibers. In this case, the fibers are used in a range of 15 to 30 parts by weight based on 100 parts by weight of dry mortar. If the amount of the fibers is less than 15 parts by weight, the toughness of the composite is deteriorated and crack control becomes difficult. , The fiber ball in the interior reduces the endurance performance and the strength is significantly lowered.

The high-toughness composite 11 having such a constitution is a precast product produced by casting in a factory.

The reinforcing rope 12 is disposed inside the tough composite body 11 and is composed of the vertical roots 13, the horizontal roots 14 and the diagonal roots 15, can do.

The vertical roots 13 are arranged in the height direction inside the tough composite 11, and the upper end thereof is joined to the upper end connecting portion 30A and the lower end thereof is joined to the lower end connecting portion 30B. The horizontal root 14 includes a horizontal single root 14a which surrounds the vertical muscle 13 and is arranged in the toughness composite 11 and an upper and a lower fixing portion 20B at the upper and lower ends of the vertical leg 13, And a horizontal bifurcation 14b to which both ends are coupled between the stiffeners 22 of the upper and lower fusing units 20B, since they can not be arranged around the vertical stripes 13 due to the vertical stiffness. The horizontal bifurcation 14b cooperates with the combined stiffener 22 to prevent the toughness PC portion 10 from expanding and breaking by collapse.

The upper end of the diagonal rope 15 is coupled to one surface of the reinforcing plate 21 of the upper end fixing portion 20A and the lower end of the diagonal rope 15 is connected to the lower end fixing portion 20B ) Of the reinforcing plate (21). At this time, the diagonal roots (15) are arranged in a diagonal direction so as to be straight without being bent in the tough composite (11) and joined to one surface of the reinforcing plate (21) Thereby enabling the diagonal root 15 to play a stable role while preventing the bent portion of the root 15 from being destroyed first.

These diagonal roots 15 are arranged in the first diagonal direction and in the second diagonal direction opposite to the first diagonal direction, respectively. 3, the diagonal roots 15 arranged in the first diagonal direction are joined to one side surface of the reinforcing plate 21 of the upper and lower fixing portions 20A and 20B, and in the second diagonal direction, The diagonal roots 15 to be arranged are connected to the other side surfaces of the reinforcing plate 21 of the upper and lower fixing portions 20A and 20B so that the diagonal roots 15 in the respective directions are crossed, do.

The thickness and the number of the diagonal rods 15 arranged in each direction can be changed and applied according to the required stress.

Next, the stone running rope 16 is a member designed to resist a pulling load caused by the rotational force of the tough PC section 10, and both ends thereof are coupled to the stiffener 21 or the stiffener 22, (11) and is buried in the high-toughness composite (11). The stone running rods 16 may be formed in various numbers, and are illustrated as being coupled to one surface and the other surface of the reinforcing plate 21 in the present embodiment.

The stone running rope 16 has a configuration in which both ends of the stone running rope 16 are extended toward the high toughness composite 11 in a state where both ends thereof are coupled to the reinforcing plate 21 or the stiffener 22, , 'A' shape, or 'ㅁ' shape, and the reinforcing bars may be partly projected toward the high-toughness composite 11 so as to be applied to the present invention.

Various methods can be used to 'bond' the reinforcing bars 12 and the fixing portions 20A and 20B and the connecting portions 30A and 30B. In this embodiment, the reinforcing bars 12 are welded to the fixing portion Or to a connection portion.

At the upper and lower ends of the tough PC section 10 exposed from the upper and lower ends of the tough PC section 10, that is, the upper and lower fusing sections 20A and 20B, A fiber sheet (not shown) may be wrapped and reinforced to prevent collapse and breakage of the compression side at both ends and to prevent abrupt strength deterioration after the maximum yield strength. At this time, it is preferable that the fiber sheet is wrapped with a width corresponding to a length equal to or longer than a length of a long side in the transverse cross section of the high toughness PC portion 10. Such a fiber sheet may be woven with one or a combination of two or more of glass fiber, carbon fiber, aramid fiber, or bazaart fiber.

The upper and lower fixing portions 20A and 20B are members for fixing the tough PC portion 10 to the upper and lower connecting portions 30A and 30B and are connected to at least a part of the reinforcing ropes 12 Are respectively installed at the upper and lower ends of the high toughness PC portion 10 while partially buried in the tough composite 11.

The fixing portions 20A and 20B are steel members made of a reinforcing plate 21 and a stiffener 22 welded to one side of the connecting portions 30A and 30B. Reinforced concrete member (11) and reinforcement rope (12) corresponding to the upper and lower ends of the tough PC section (10)) and is made up of steel reinforced concrete structure (SRC tank). That is, the fixing units 20A and 20B are constituted by the SRC member and at the same time, the cross-sectional area is designed to be larger than the toughness PC unit 10 to increase the rigidity and the proof strength. Focus.

The fixing units 20A and 20B include a reinforcing plate 21 vertically installed at the center of the long side of the connecting portions 30A and 30B and coupled to the side surface of the diagonal frame 15, And a stiffener 22 vertically installed on the connecting portions 30A and 30B and the reinforcing plate 21 for preventing reinforcement and buckling / deformation. At this time, the stone runway 16 is welded to the side surfaces of the reinforcing plate 21 and the stiffener 22, and the horizontal two legs 14b are welded between the stiffeners 22.

The upper and lower connection portions 30A and 30B are members for connecting the joint member C of the existing structure and the seismic member according to the present invention and have one end joined to the upper or lower end fixing portion 20B, Is joined to a joining member (C) mounted on an existing building or an existing building. Such a connection portion is made of a steel material and can be easily coupled to the joint member C of the existing structure through bolt joint or weld joint.

The connection portion is manufactured in the factory together with the above-described high-toughness PC portion 10 and the fixing portions 20A and 20B and includes an upper connection portion 30A, an upper fixing portion 20A, a tough PC portion 10, The fixing portion 20B and the lower end connecting portion 30B so as to be integrally manufactured.

The connecting portions 30A and 30B are preferably made of H-shaped steel (prefabricated product) and designed to have a width at least two times longer than the length of the long side of the end face of the tough PC portion 10 in order to secure sufficient strength and rigidity Do.

The horizontal roots 13 of the reinforcing ropes 12 are welded to the connecting portions 30A and 30B so that the seismic forces (horizontal loads) transmitted to the connecting portions 30A and 30B are directly applied to the high toughness PC portion 10 Lt; / RTI >

As described above, when a seismic force (horizontal load) acts on the upper and lower connecting portions 30A and 30B through the joint member C provided on the beam B of the existing building in the event of an earthquake, the upper and lower fixing portions 20A, 20B are transmitted through the reinforcing plate 21 to the diagonal rope 15 to provide an earthquake-resistant reinforced PC portion 10 having excellent horizontal resistance and shear deformation performance, It can be installed outdoors, in the plane (bottom of the beam), and outboard (beam side).

That is, as shown in FIGS. 6 and 7, it may be installed in the interior of the existing building, or may be installed outside the exterior of the existing building, as shown in FIGS. 8 and 9.

In this case, in the case of being installed in the interior of the room, the seismic strengthening system according to the present invention can be mounted on the joint member C to be joined to the beam B and the column P to perform seismic strengthening. It is possible to mount an anti-seismic reinforcement system according to the present invention in a state where the joining member C is preliminarily provided with steel frame or reinforced concrete outside the beam B to perform seismic reinforcement.

As shown in FIG. 10, when the anti-seismic reinforcement system according to the present invention is installed in the non-seismic RC frame, the horizontal strength and the maximum endurance of the non-seismic RC frame It can be seen that the horizontal deformation capability in the horizontal direction can be greatly increased. Also, it can be seen that the seismic strengthening system can prevent the sudden shear destruction of the building by maintaining the stable strength even after the maximum strength.

It is to be understood that the invention is not limited to the disclosed embodiment, but is capable of many modifications and variations within the scope of the appended claims. It is self-evident.

10: High Toughness PC Part 11: High Toughness Composite 12: Reinforcement Bar
13: the medial rectus 14: the horizontal line 15: the diagonal
16: Go to the stone
20A: upper end fixing unit 20B: lower end fixing unit
21: reinforcing plate 22: stiffener
30A: upper connection part 30B: lower connection part
C: joint member P: column B: beam

Claims (7)

Strain hardening behaviors that increase stress with increase of strain without stress decrease even when initial tensile strain is 1.5% or more under direct bending and tensile load, and a multiple crack characteristic that microcracks are homogeneous and numerous (10) comprising a rigid tough composite (11) and a reinforcing rope (12) laid inside the rigid tough composite (11);
The upper and lower fixing portions 20A and 20B are installed at the upper and lower ends of the high toughness PC portion 10 while partially buried in the high toughness composite 11 in a state of being coupled with at least part of the reinforcing ropes 12, ; And
(30A, 30B), one end of which is coupled to the upper or lower fixing portion (20A, 20B) and the other end is coupled to an existing building,
The reinforcement rope 12 is composed of a vertical rope 13, a horizontal rope 14, a diagonal rope 15 and a stone turn rope 16,
Each of the fusing units 20A and 20B includes a reinforcing plate 21 vertically installed on the connecting portions 30A and 30B and coupled with the diagonal roots 15 on a side surface thereof, And a stiffener (22) vertically installed on the connecting portions (30A, 30B) and the reinforcing plate (21)
Both ends of the perpendicular rods 13 are coupled to the upper or lower connection portions 30A and 30B, respectively,
The diagonal roots (15) are arranged in the first diagonal direction and the second diagonal direction so as to be straight without being bent, and the diagonal roots (15) arranged in the respective directions are joined to different sides of the reinforcing plate And,
Characterized in that both ends of the stone runway (16) are joined to the stiffener plate (21) or the stiffener (22) and the stop is extended toward the tough composite (11) Seismic Retrofit System of Buildings Improved Horizontal Resistance and Shear Deformation by Using High Tough Precast Concrete. delete delete delete delete The method according to claim 1,
The upper and lower ends of the high-tensile strength PC portion 10 exposed from the upper and lower fixing portions 20A and 20B are formed by laminating a fibrous sheet Reinforced precast concrete is used to reinforce horizontal resistance and shear deformation performance of buildings. The method according to claim 6,
Characterized in that the fiber sheet is wrapped with a width corresponding to a length of at least 1/2 of the long side length in the transverse section of the high toughness PC section (10). The toughness precast concrete The seismic strengthening system of the building improved.

Images