JP2000064631A - Seismic reinforcement structure of existing columns and seismic reinforcement method of existing columns - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide an earthquake-resistant reinforcing structure capable of reinforcing an existing column to which a high axial force is applied, while taking advantage of excellent economic efficiency and workability by winding a spiral hoop. SOLUTION: The earthquake-resistant reinforcement structure comprises a first spiral hoop 1 disposed around an outer peripheral surface of an existing column 31 at a constant interval and a fixed interval outside the first spiral hoop 1. A second helical hoop muscle 11 disposed between the mortars 57 and 67, and inner and outer mortars 57 and 67 which fill gaps between the spiral hoop muscles 1 and 11 and cover the gaps. The first and second spiral hoops 1 and 11 are arranged so that one is located at the center of the other, and are wound in the same direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic retrofitting structure and a method for seismic retrofitting an existing column made of reinforced concrete from the outer periphery.

[0002]

2. Description of the Related Art Reinforcement of existing reinforced concrete columns on elevated roads has been actively carried out after the Great Hanshin Earthquake. As one of the seismic retrofitting methods of this type, the present applicant has shown in FIGS. Recently proposed a new construction method (Japanese Patent Laid-Open No. 10-14803).
No. 8 publication).

In this seismic retrofitting method, first, the concrete of the existing pillars 51 is surface-treated so as to be compatible with the mortar to be sprayed later, and then the reinforcing bars 58 for binding are hung vertically at the four outer corners of the pillars 51 (Fig. 5). Next, the spiral hoop muscle 1 formed by processing the PC steel rod into a spiral bundle is shown in FIG.
As shown in, the loop surface is arranged vertically so as to face the vicinity of the outer surface of the existing column 51, and the tip bent at a right angle to start winding is inserted and fixed in the hole at the lower end of the existing column 51. With the bundle of hoop muscles 1 held vertically,
While rotating in the direction in which the bundle indicated by arrow X in (B) is unwound,
The loop is wound around the existing column 51 in the direction indicated by the arrow Y and horizontally wound around the lower end outer periphery of the existing column 51 one loop at a time. After the winding of one bundle is completed, the upper end of the spiral loop streak 1 which is wrapped around the lower end outer circumference of the column 51 is lifted above the column 51 as shown in FIG. 5B, and a predetermined pitch P = 5 cm is formed and held. Then, in this state, the four corners of the spiral loop muscle 1 are bound and fixed to the spur muscles 58 by binding wires. Next, grout is injected into the anchor hole into which the tip of the spiral hoop muscle 1 that has been wound up is inserted and fixed, and then mortar is sprayed into the gap between the existing column 51 and the spiral hoop muscle 1 while the spiral hoop is also filled. Cover muscle 1 with mortar, thickness 4
As a mortar layer 57 of 0 mm, as shown in FIG.
The seismic retrofitting of the existing columns 51 is completed.

The pitch P = 5 cm of the spiral hoop muscle 1 is
Determined from the allowable load W that the total cross section of the spiral hoop muscle should bear per unit length column, the diameter of the PC steel rod SBPD130 / 145, the yield point, and the number per column 1 m are d = 7.1 mm, σy = 134 kgf /
Since mm ² and n = 20, the allowable load W is W = σy × (πd ²
/ 4) × 2n = 212212kg. On the other hand, considering the maximum shear stress τ (kgf / mm ² ) generated in the spiral hoop muscle 1 due to twisting during winding shown in FIG. 4 (A), τ = 16T /
(πd ³ ) = 16GI / (πd ³ ) = 16G (πd ⁴ θ / 32) /
(πd ³ ) = Gdθ / 2 = ... (1) However, T, G, θ
Is the torsional rigidity and lateral elastic modulus (kgf / m) of each spiral hoop muscle 1.
m ² ), the twist angle per unit length (rad / mm). the above
Θ in the formula (1) is constant because the twist angle increases by 90 ° each time the spiral hoop muscle 1 is wound around the column 51 by a half circumference, and for example, if the column cross section is 900 mm × 900 mm, θ = (πrad / 18
0-) La (90- / 1800 mm) = 0.000873 (rad / mm). Also,
G in the above formula (1) is given by G = E / 2 (ν + 1) E: Young's modulus, ν: Poisson's ratio, and is a constant value (8100 kgf / mm ² ) even for PC steel rods which are steel. Therefore, spiral hoop muscle 1
The maximum shear stress τ that occurs in the
It will be proportional to d. On the other hand, the maximum allowable shear stress τa of a material is τa = σy /, where γy is the yield point of the material.
Since it is given by 2√3 ... (2), the maximum allowable shear stress of the spiral hoop muscle 1 is proportional to the yield point σy of the material.

Therefore, the PC steel rod SB which is the spiral hoop muscle 1
Substituting the material property values and dimensions of PD into the above equations (1) and (2) to obtain the maximum shear stress τ and the maximum allowable shear stress τa, τ = 25.1
It can be seen that (kgf / mm ² ) <τa = 38.7 (kgf / mm ² ), which enables winding within elastic deformation. This is because the high strength and small diameter PC steel bar SWPR1 is used for the spiral hoop muscle 1, so that the maximum allowable shear stress τa can be increased and the maximum shear stress τ can be decreased in inverse proportion to the diameter. .

[0006]

In the conventional seismic retrofitting method for existing columns, the design axial force ratio (axial compressive stress / concrete design compressive strength) of the abutment columns of elevated roads is 0.1. The following ground structures are targeted. However, in the pillar of the underground structure deep underground, the earth pressure is applied in addition to the overlaid load, and the axial force ratio is increased to 0.2 to 0.5, and as a result, the deformability of the pillar is reduced. In order to secure and guarantee the deformation performance required for an underground structure, it is necessary to use a spiral hoop muscle having a larger diameter than that for the above-ground structure or to make the pitch P of the spiral hoop muscle narrower. However, J
Maximum diameter of PC steel rod SBPD specified by IS G 3137 d
Is 12.6 mm, and as the diameter d increases, the maximum shear stress τ that occurs in the spiral hoop muscle, that is, the force required for winding, increases proportionally as described in equation (1), and the winding work is performed manually. There is a limit to how large the diameter can be because it is not possible.
Further, since the mortar 57 is sprayed on the gap between the column 51 and the spiral hoop muscle 1, this gap needs to be 33 mm or more, and there is a limit to narrowing the pitch. for that reason,
For underground structure columns with a large axial force ratio and columns in the lower floors of super high-rise buildings, spiral hoop reinforcements with a large diameter or pitch exceeding the above limits are required. Is not applicable.

Therefore, an object of the present invention is to add a high axial force while taking advantage of the excellent economical efficiency and workability by winding the spiral hoop muscles by devising the arrangement of the spiral hoop muscles to have a high density. An object of the present invention is to provide a seismic retrofitting structure and method for existing columns that can also reinforce existing columns.

[0008]

In order to achieve the above object, the seismic reinforcement structure for an existing column according to claim 1 is arranged around the existing column at a constant distance from the outer peripheral surface of the existing column. A first spiral hoop muscle, and a second spiral hoop muscle arranged outside the first spiral hoop muscle at a constant interval,
It is characterized by comprising the above-mentioned existing column and mortar filled in the gap between the spiral hoop muscles.

In the seismic retrofit structure for existing columns according to claim 1, a first spiral hoop reinforcement and a second spiral hoop reinforcement are sequentially arranged at regular intervals on the outer circumference of the existing column, and these spiral hoop reinforcements are Mortar is filled in the gap between the existing columns. In other words, even if the arrangement density of each spiral hoop muscle (the number per unit pillar length) is kept the same as before so that mortar can be filled, the existing pillar is doubled by the first and second spiral hoop muscles. Since it is surrounded, when the spiral hoop muscles with the same diameter are used with the same arrangement density, the existing underground columns with an axial force ratio of 2 are reinforced with sufficient deformability. In addition, if the diameters and the arrangement densities of the first and second spiral hoop muscles are made different, it is possible to reinforce existing columns having a high axial force ratio with sufficient deformation performance while setting the amount of reinforcements arbitrarily or optimally. it can.

According to a second aspect of the seismic retrofit structure for an existing column, the first spiral hoop reinforcement and the second spiral hoop reinforcement are wound in directions opposite to each other.

In the seismic reinforcement structure for the existing column of claim 2, since the first and second spiral hoop reinforcements are wound around the existing column in mutually opposite directions, positive and negative torsion moments are applied around the column axis. However, since either of the spiral hoop muscles always bears the tensile main stress caused by this, it is possible to provide a seismic reinforced structure having a strong balance against positive and negative twists.

According to a third aspect of the seismic reinforcement structure for an existing column, the first spiral hoop reinforcement and the second spiral hoop reinforcement are arranged such that one of them is located substantially in the center of the other, and they are arranged in the same direction as each other. It is characterized by being wrapped.

According to the seismic retrofitting structure for an existing column of claim 3, since the first and second spiral hoop reinforcements are arranged such that one of them is located substantially in the center of the other, the shear strength of the column is more uniform. become. Furthermore, even if the arrangement density of the spiral hoop muscles is the same, the distance between the first and second spiral hoop muscles is smaller than that of claim 2, the lateral restraint effect of concrete is increased, and the buckling of the main bar is prevented. It is possible to have a seismic reinforcement structure.

According to a fourth aspect of the present invention, there is provided an earthquake-proof reinforcing method for an existing column, wherein the first column and the first column are wound around the existing column at a constant distance from the outer peripheral surface of the existing column to wind the first helical hoop. The mortar is filled in the gap between the muscles, the second spiral hoop muscle is wound around the mortar and the first spiral hoop muscle at regular intervals, and the mortar is filled in the gap between the mortar and the second spiral hoop muscle. It is characterized by doing.

In the seismic retrofitting method for existing columns according to claim 4, since the first and second spiral hoop reinforcements are wound around the existing columns at regular intervals, a ring-shaped hoop reinforcement is used for the column as in the conventional case. Since there is no need to weld the seams by fitting them one by one, the existing columns can be efficiently and firmly seismically reinforced by the construction of efficient hoop reinforcements with few defects. Further, the first and second hoop muscles are arranged at regular intervals on the outer circumference of the existing column, and the mortar is filled in the gap between these spiral hoop muscles and the existing column. Therefore, the same as described in claim 1. For that reason, while maintaining the arrangement density of each spiral hoop muscle (the number per unit column length) at the conventional value that allows mortar filling, existing columns with high axial force ratio should be reinforced with sufficient deformation performance. You can

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 and FIG. 2 show examples of the seismic reinforcement structure of the existing columns of the present invention after the outer mortar construction and before the construction respectively. As shown in FIG. 1, the seismic reinforcement structure of the existing columns is arranged at a constant interval from the outer peripheral surface of the existing columns 31, such as bridge piers, which stand up from deep underground and are subjected to large axial compressive stress due to earth pressure. The first spiral hoop muscle 1, the second spiral hoop muscle 11 arranged outside the first spiral hoop muscle 1 at a constant interval, and the existing column 3
1 and the mortar 57, 67 that is constructed so as to fill the gap between the spiral hoop muscles 1 and 11 and cover them.
In addition, in the existing pillar 31 shown in FIG. 1, 6 is a vertical streak vertically arranged along the periphery of the rectangular cross section of the pillar, and 7 is a hoop horizontally arranged around the longitudinal streak 6. It is a muscle.

The spiral hoop streaks 1 and 11 are required to reinforce the entire length of the column. The small-diameter deformed PC steel bar (JIS G 3137) having a nominal diameter of 7.1 mm and having substantially the same length as described in the conventional example of FIGS. To
Reinforcing bars 58, which are processed into a rectangular spiral bundle larger than the cross section of the existing pillar 31, and which are erected at the four corners of the pillar on the outer circumference of the lower end of the existing pillar 31 by the same method as in FIG. 4 (FIG. 3 (A)). (See FIG. 3) or the reinforcing bar 68 (see FIG. 3 (F)) and wound all around, and then the tie wire 2 (see FIG. 3) at the same pitch P = 5 cm as the above-mentioned conventional example.
(See (C)) and fixedly arranged over the entire length of the column.
The diameter d and the pitch P of the spiral hoop muscles 1 and 11 are the same as those of the conventional example, but the existing column 31 is doubly surrounded by the spiral hoop muscles 1 and 11, so the mortar is filled from the gap between the spiral hoop muscles. In addition, the existing column 31 to which the axial load twice that of the conventional one is applied can be reinforced with sufficient deformation performance.

The wrapping of the first and second spiral hoop muscles is shown in FIG. 2 (A), and the spiral hoop muscles 1 and 11 of FIG. 1 and those of the same direction corresponding to claim 3, In (B), there are spiral hoop muscles 21 and 11 in the opposite direction corresponding to claim 2. 2 is a view taken along the line II-II of FIG. 1 (A) before the outer mortar 67 is sprayed, and the surface of the outer mortar 67 is a one-dot chain line, and the first spiral hoop muscles 1, 21 and The surfaces of the existing columns 31 are shown by broken lines.

In the winding in the same direction in FIG. 2 (A), the first spiral hoop muscle 1 on the inner side goes up 1/4 pitch every time it goes upwards in a left-handed manner, 1a, 1b, 1c, 1d side by side. While making one pitch P in one round, the outer second spiral hoop muscle 11 is located at the center of each pitch of the first spiral hoop muscle 1 and is upwardly left-handed on each side 11a, 11a.
Each time it goes to b, 11c, 11d, it goes up by 1/4 pitch to make one pitch P in one turn. In the reverse winding of FIG. 2 (B), the first spiral hoop muscle 21 on the inner side is 1/4 each time it goes upward and goes to the right winding 21a, 21b, 21c, 21d side by side.
While the pitch goes up to form one pitch P in one lap, the outer second spiral hoop streak 11 goes up by 1/4 pitch every time it goes to the left by 11a, 11b, 11c, 11d one by one in the left-handed direction. While forming one pitch P on the circumference, both spiral hoop streaks 21 and 11 intersect the surface shown in FIG. 2 (B) and the back surface thereof at substantially the center of the columnar surface.

In both the winding directions shown in FIGS. 2 (A) and 2 (B), as already described, the existing column 31 is doubly surrounded to double the deformation performance, and a double axial load is applied to the conventional column. Be sure to reinforce existing columns. Further, in the case of winding in the same direction in FIG. 2 (A), one of the first and second spiral hoop muscles 1 and 11 is located at the center of the other, so the shear strength of the column becomes more uniform. Furthermore, even if the arrangement density of the spiral hoop muscles is the same, the interval between the first and second spiral hoop muscles 1 and 11 is smaller than that in the opposite direction of FIG. As the size increases, a seismic strengthening structure that is effective in preventing buckling of the main bar can be obtained.

On the other hand, when winding in the opposite direction of FIG.
The first spiral hoop muscle 21 bears a negative (counterclockwise) torsional moment that causes a tensile principal stress along the winding direction, and prevents the occurrence of cracks that propagate orthogonally to the winding direction. At the same time, the second spiral hoop muscle 11
A positive (clockwise) torsional moment that produces a tensile principal stress along the winding direction is taken into account, and the occurrence of cracks that propagate perpendicularly to the winding direction is prevented. That is, the existing column 31 is reinforced against both positive and negative torsion moments, and a seismic reinforced structure having a strong balance against torsion in both directions can be obtained.

In the above embodiment, as the material of the spiral hoop bar 1, a small-diameter deformed PC steel bar (JIS G 3112) having a yield point 3 to 5 times higher than that of general deformed steel bar SD345 for reinforced concrete (JIS G 3112). 3137) is used, it is possible to bear the load of the column by using a small amount of small diameter steel rod as described in paragraph [0004], and it is possible to significantly reduce the required weight of the spiral hoop muscles for construction work. The weight can be reduced. Also,
Since the yield point is high, the maximum allowable shear stress τa described in Eq. (2) of the spiral hoop muscle can be increased, and it is possible to wind securely within the elastic deformation range without entering the plastic deformation range, and because it has a small diameter. , Which occurs in the spiral hoop muscle during winding
The maximum shear stress τ described in Eq. (1), that is, the force required for winding can be reduced, which facilitates construction, and also has the advantage that the gap between the spiral hoop muscles is widened and mortar filling is easy. is there. The spiral hoop muscle 1
As a small diameter deformed PC steel bar with a nominal diameter of 9.0, 10.7, 12.6 mm
(JIS G 3137) can also be used. Since the cross-sectional area of the steel rod is proportional to the square of the nominal diameter, the pitch of the steel rod to carry the same load also increases in proportion to the square of the nominal diameter, and the increment of the gap between the steel rods is the increment of the nominal diameter. The larger, the thicker the PC steel bar, the wider the gap for mortar filling.

In the above-mentioned embodiment, the diameters and arrangement densities of the first and second spiral hoop muscles are made the same, but they can be made different, whereby the muscle arrangement amount can be set arbitrarily or optimally. Existing underground columns with high axial force ratio can be reinforced with sufficient deformation performance. Further, in the above-described embodiment, the spiral hoop muscle is wound around the existing column in a double manner, but the first and second spiral hoop muscles referred to in the present invention are the first and second spiral hoop muscles. It does not mean only 1,21; 11, but also a spiral hoop muscle wound in three or more layers. Therefore, if the existing column 31 is reinforced with triple or more spiral hoop reinforcements, it takes time to construct, but if the same diameter and pitch are used, the reinforcing strength can be increased proportionally, and if the same reinforcing strength is used, the diameter can be reduced. The pitch can be increased.

FIG. 3 shows, in sequence, the procedure for constructing the seismic retrofit structure for the existing columns of FIG. 2 (A). As shown in FIG. 3 (A), the seismic retrofitting method first treats the concrete surface of the existing underground pillar 31 so that it is compatible with the mortar to be sprayed later, and then binds it to the four outer corners of the pillar 31. A supplementary bar 58 is laid vertically. Next, the right-angled bent portion at the tip of the first spiral hoop muscle 1 is hooked on the lower end corner of the existing column 31, and the loop surface of the bundle of the first spiral hoop muscle 1 is hooked as shown in FIG. 3 (B). The bundle is held so as to face the outer surface of the pillar along the vertical direction, and while keeping this state, the bundle is rotated in the arrow X direction shown in FIG.
The loops are wound around the pillar 31 in a left-handed manner.

After the winding of one bundle is completed, the bundle of the first spiral hoop muscles 1 stacked on the outer periphery of the lower end of the existing column 31 is
Lift up to the upper end of the existing pillar 31 by hand or a lifting platform, and as shown in FIG. 3 (C), in order from the top spiral loop line, one at each corner of the rectangle, and form a scale 3 indicating the engraved pitch. In addition, fixing to the reinforcing bar 58 with the binding wire 2 is repeated up to the lower end of the existing column 31 so that it is lowered by 1/4 pitch every time one side of the column is advanced. When the arrangement of the first spiral hoop muscle 1 is completed in this way, as shown in FIG. 3 (D), partition plates 4, 4 are erected at both ends of the pillar surface onto which mortar is first sprayed, and this is used as a partition. Existing pillar 31 and first
The inner mortar 57 is sprayed by the spray gun 5 so as to fill the space between the spiral hoop muscles 1 of 1. and cover the first spiral hoop muscles 1. When the inner mortar 57 has been sprayed on the four sides of the existing pillar 31 and the partition plate 4 is removed, as shown in FIG.
It becomes like (E).

Next, as shown in FIG. 3 (F), as shown in FIG.
After the supplementary bar 68 is hung in the same manner as described in (A), the second spiral hoop muscle 11 (see FIG. 2 (A)) is processed in the same manner as described in FIGS. 3 (B) and (C). , Wrapping, bundling and arranging them in the center of each pitch of the first spiral hoop muscle 1,
In the same manner as described in (D), the outer mortar 67 (see FIG. 1) is sprayed, and the seismic reinforcement is completed as shown in FIG. It should be noted that if the four corners of the rectangle of the first spiral hoop muscle 1 are exposed at the end of the spraying of the inner mortar 57 shown in FIG. 3 (F), even when using the reinforcement muscle 68 without the scale 3, Positioning and bundling of the second spiral hoop muscle 11 is facilitated. In addition, if mesh mesh is laid on the entire surface of the first and second spiral hoop muscles 1 and 11 that have been bound,
Easy to spray and attach inner and outer mortar 57, 67,
And you can be sure.

Although the construction procedure of the seismic retrofit structure for the existing columns in FIG. 2B is not shown in the drawing, the first spiral hoop bar 2
In the winding of No. 1, the bundle of spiral hoop muscles processed into a rectangle is turned upside down from FIG. 3 (B) and is vertically held by facing the column, and is rotated in the direction opposite to the arrow X and arrow Y. And the second spiral hoop muscle 11 is partially exposed from the inner mortar 57 at the center of the pillar surface.
The procedure is the same as that described with reference to FIG. 3, except that it is arranged so as to intersect the spiral hoop muscle 21.

As described above, the winding of the spiral hoop muscles, which is the main part of the seismic retrofitting method for the existing pillars of the present embodiment, is performed by making the loop surfaces of the spiral hoop muscles 1, 11, 21 face the outer surface of the existing pillar 31. While holding it along the vertical direction, rotate it in the direction in which the bundle is unwound (arrow X in FIG. 3 (B)) and wrap around the existing pillar (arrow Y in FIG. 3 (B)) and wind one loop at a time. Since the corners of the rectangular hoop muscles are not opened 90 ° further by bending force in the rectangular plane, the spiral hoop muscles need only be twisted 90 ° per semi-perimeter of the column, so it is within the elastic deformation range. In addition to being able to wind around, the vertical holding of the bundle of spiral hoop muscles allows construction even if the space around the column is narrow. Furthermore, in the present embodiment, it is not necessary to externally fit the ring-shaped hoop muscles to the pillars one by one and weld the seams, so that it is possible to efficiently perform seismic retrofitting of existing pillars with few defects. it can.

Further, in the above-mentioned embodiment, since the high strength steel having the yield point of 134 kgf / mm ² is used as the material of the spiral hoop muscles 1, 11, 21 and, while maintaining the reinforcing strength equivalent to the conventional one, The required weight of the hoop muscles can be halved, the construction can be made lighter, and the allowable shear stress due to the increase in the yield point increases and the maximum torsional shear stress that accompanies the winding in proportion to the smaller diameter of the hoop muscles reduces. The winding can be further facilitated while surely ensuring the winding within the elastic range. Also, spiral hoop muscles 1, 11, 21
By increasing the strength and reducing the diameter, the gaps between the spiral hoop muscles are widened, and mortar filling is facilitated.

In the above embodiment, the loop shape of the spiral hoop muscle is square, but this shape can of course be circular, rectangular or the like according to the sectional shape of the existing column. Further, the material of the spiral hoop muscle is not limited to the SBPD of the above-mentioned embodiment, and may be any material as long as the maximum torsional shear stress due to winding falls within the elastic range. Furthermore, in the above-mentioned embodiment, since the mortar 57, 67 is constructed by spraying after winding the spiral hoop muscles, the spiral hoop muscles can be covered without the need for a temporary frame for mortar filling. The efficiency can be further improved, and the anticorrosion coating of the spiral hoop can be omitted. Alternatively, a temporary frame may be assembled around the spiral hoop muscle, and mortar may be injected into the temporary frame for construction.

[0031]

As is apparent from the above description, claim 1
The existing column's seismic reinforcement structure consists of a first spiral hoop streak that is arranged around the existing column at a fixed interval from the outer peripheral surface of the existing post, and a constant interval outside the first spiral hoop streak. Since the second hoop streak and the mortar filled in the gap between the existing column and the spiral hoop streak are provided, the existing column does not have a problem in mortar filling, for example, the same density as the conventional one. Since it is doubly surrounded by the first and second spiral hoop muscles with the same diameter as the conventional one, the existing column that receives twice the axial load of the conventional one is reinforced with sufficient deformation performance. By making the diameter and the arrangement density of the second spiral hoop muscle different, the existing column having a high axial force ratio can be reinforced with sufficient deformation performance while setting the amount of reinforcement to be arbitrarily or optimally set.

In the seismic retrofitting structure for an existing column according to claim 2, since the first and second spiral hoop reinforcements are wound around the existing column in mutually opposite directions, both positive and negative torsion moments about the column axis can be obtained. Since the spiral hoop muscles play a role, it is possible to create a seismic reinforced structure that is well balanced and strong against positive and negative twists.

In the seismic retrofit structure for an existing column of claim 3, the first and second spiral hoop reinforcements are arranged so that one is located substantially in the center of the other and are wound around the existing column in the same direction. Therefore, the shear strength of the column becomes more uniform, and the interval between the first and second spiral hoop bars becomes smaller than that of claim 2, so that the lateral restraining effect of concrete can be increased and the buckling of the main bar is increased. Can be effectively prevented.

According to a fourth aspect of the present invention, there is provided an earthquake-proof reinforcing method for an existing pillar, wherein the first pillar and the first spiral hoop are wound around the existing pillar at regular intervals from the outer peripheral surface of the existing pillar, and the first spiral hoop is wound around the existing pillar. The mortar is filled in the gap between the muscles, the second spiral hoop muscle is wound around the mortar and the first spiral hoop muscle at regular intervals, and the mortar is filled in the gap between the mortar and the second spiral hoop muscle. Since there is no need to weld the seams by externally fitting one ring-shaped hoop muscle to the column one by one as in the conventional method, the existing columns can be efficiently and strongly reinforced by seismic reinforcement by the construction of efficient hoop muscles with few defects. Therefore, it is possible to reinforce the existing columns having a high axial force ratio with sufficient deformation performance while maintaining the arrangement density of each spiral hoop muscle at a conventional value that allows mortar to be filled.

[Brief description of drawings]

FIG. 1 is a horizontal cross-sectional view showing an example of an earthquake-proof reinforcement structure for an existing column of the present invention after an outer mortar construction and a vertical cross-sectional view taken along line bb thereof.

FIG. 2 is a line II-II of FIG. 1 (A) showing an example of the seismic reinforcement structure of the existing column of the present invention before the outer mortar construction in which the first and second spiral hoop muscles are wound in the same direction and in the opposite direction. FIG.

FIG. 3 is a perspective view showing in sequence the construction procedure of the seismic resistant reinforcement structure for the existing columns of FIG. 2 (A).

FIG. 4 is a perspective view and a side view showing a method of arranging spiral hoop muscles, which is a main part of a conventional earthquake-proof reinforcement method.

FIG. 5 is a plan view, a side view and an enlarged plan view showing the conventional seismic retrofitting method.

[Explanation of symbols]

1, 21 ... First spiral hoop muscle, 2 ... Binding line, 3 ... Scale, 4 ... Partition plate, 5 ... Spray gun, 31 ... Existing column, 57
… Inner mortar, 58… Reinforcements, 67… Outer mortar,
68 ... reinforcements.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Nobuyuki Daimon             3-19-6 Higashi-Ueno, Taito-ku, Tokyo Imperial City             High-speed transportation company (72) Inventor Seibayashi Seibu             3-19-6 Higashi-Ueno, Taito-ku, Tokyo Imperial City             High-speed transportation company (72) Inventor Shikibe             3-19-6 Higashi-Ueno, Taito-ku, Tokyo Imperial City             High-speed transportation company (72) Inventor Jiro Inose             Metro Akasaka 5-4-5, Minato-ku, Tokyo opened             Within the stock company (72) Inventor Kazunari Takahashi             2-2-2 Matsuzaki-cho, Abeno-ku, Osaka-shi, Osaka             No. Okumura Gumi Co., Ltd. (72) Inventor Tetsuya Hironaka             2-2-2 Matsuzaki-cho, Abeno-ku, Osaka-shi, Osaka             No. Okumura Gumi Co., Ltd. (72) Inventor Ceiling Mikio             2-2-2 Matsuzaki-cho, Abeno-ku, Osaka-shi, Osaka             No. Okumura Gumi Co., Ltd. (72) Inventor Toshiharu Nakamura             2-2-2 Matsuzaki-cho, Abeno-ku, Osaka-shi, Osaka             No. Okumura Gumi Co., Ltd. F-term (reference) 2E163 FA02 FD47                 2E176 AA04 BB03 BB15 BB17 BB29

Claims (4)

[Claims] 1. A first spiral hoop muscle disposed around an existing pillar at a constant distance from an outer peripheral surface of the existing pillar, and a first spiral hoop muscle arranged at a constant distance outside the first spiral hoop muscle. An earthquake-proof reinforcement structure for an existing column, comprising: a second spiral hoop reinforcement provided and mortar filled in a gap between the existing column and the spiral hoop reinforcement. 2. The seismic retrofit structure for an existing column according to claim 1, wherein the first spiral hoop reinforcement and the second spiral hoop reinforcement are wound in directions opposite to each other. Seismic reinforcement structure. 3. The seismic reinforcement structure for an existing column according to claim 1, wherein the first spiral hoop muscle and the second spiral hoop muscle are arranged such that one of them is located substantially in the center of the other, Seismic reinforcement structure for existing columns, which are wound in the same direction as each other. 4. A first spiral hoop muscle is wound around an existing pillar at a constant distance from the outer peripheral surface of the existing pillar, and mortar is filled in the gap between the existing pillar and the first spiral hoop muscle. Seismic resistance of existing columns, characterized in that the second spiral hoop muscle is wound around the mortar and the first spiral hoop muscle at regular intervals, and the mortar is filled in the gap between the mortar and the second spiral hoop muscle. Reinforcement method.