JP6804736B2 - Method of constructing horizontal resistance structure of existing building and horizontal resistance structure of existing building - Google Patents

Description

The present invention relates to a horizontal resistance structure of an existing building and a method of constructing a horizontal resistance structure of an existing building.

Conventionally, seismic isolation retrofit construction has been carried out to provide seismic isolation layers on the foundations and intermediate floors of existing buildings. For example, there is a construction method in which the ground directly under the foundation of an existing building is excavated, multiple temporary steel pipe piles are placed, and while the existing building is temporarily supported by the steel pipe piles, seismic isolation devices are sequentially installed directly under the foundation. It is known (see Patent Document 1).

Since the ground is excavated during the seismic isolation work, the horizontal resistance due to friction between the existing building and the ground is reduced. For earthquake countermeasures, it is necessary to fix the foundation of the existing building, and steel plate walls and braces may be installed in the excavation space to ensure horizontal resistance.

Japanese Unexamined Patent Publication No. 2016-11520

However, if a steel plate wall or a brace is installed in the excavation space, there is a problem that it hinders the removal of excavated earth and sand and the import of construction materials such as seismic isolation devices.

Therefore, the present invention has been made in view of the above circumstances, and provides a method for constructing a horizontal resistance structure of an existing building and a horizontal resistance structure of an existing building that do not hinder the loading and unloading of construction materials and the like.

In order to achieve the above object, the present invention employs the following means.
That is, the horizontal resistance structure of the existing building according to the present invention is a horizontal resistance structure that supports the existing building when the seismic isolation device is installed in the excavation space formed directly under the existing building, and the seismic isolation structure. A lower pile that is placed near the device and is supported by the ground and extends upward, and an upper pile that is placed above the lower pile and is supported by the existing building and extends downward, and extends vertically and inside. It is characterized in that a joined steel pipe in which an upper portion of the lower pile and a lower portion of the upper pile are arranged, and a mortar filled inside the joined steel pipe are provided.

In the horizontal resistance structure of the existing building configured in this way, the bonded steel pipes are arranged outside the upper part of the lower pile and the lower part of the upper pile. The inside of the joined steel pipe is filled with mortar. Therefore, the hardened mortar connects the lower pile supported by the ground and extending upward and the upper pile supported by the existing building and extending downward, so that the horizontal resistance of the existing building can be secured.
The structure is such that the lower pile and the upper pile are connected in the vertical direction, and since the steel plate wall, brace, etc. are not installed in the excavation space as in the past, it does not hinder the loading and unloading of construction materials and the like.

Further, in the horizontal resistance structure of the existing building according to the present invention, it is preferable that the inner surface of the joined steel pipe is provided with a first protruding portion that protrudes inward.

In the horizontal resistance structure of the existing building configured in this way, the inner surface of the joined steel pipe is provided with a first protruding portion that protrudes inward, and the first protruding portion is embedded in the mortar. The steel pipe is prevented from falling off.

Further, in the horizontal resistance structure of the existing building according to the present invention, a second projecting portion projecting outward is provided on the outer surface of at least one of the lower pile and the upper pile, and the first The protruding portion may be arranged above the second protruding portion.

In the horizontal resistance structure of the existing building configured in this way, a second protruding portion protruding outward is provided on the outer surface of at least one of the lower pile and the upper pile, and is provided on the joined steel pipe. The first protruding portion is arranged above the second protruding portion. Therefore, the second protrusion provided on at least one of the lower pile and the upper pile supports the hardened mortar, and the first protrusion of the joined steel pipe receives a reaction force from the second protrusion via the mortar. Therefore, the joint steel pipe is further suppressed from falling off.

Further, in the horizontal resistance structure of the existing building according to the present invention, the length of the vertically overlapping portions of the joined steel pipe, the lower pile and the upper pile is 1 / of the diameter of the joined steel pipe. It may be 2 or more.

In the horizontal resistance structure of the existing building configured in this way, the length of the vertically overlapping portion of the joined steel pipe and the lower pile and the upper pile is 1/2 or more of the diameter of the joined steel pipe. Therefore, the horizontal resistance of the existing building can be surely secured.

Further, the method for constructing the horizontal resistance structure of the existing building according to the present invention is a method for constructing the horizontal resistance structure of the existing building that supports the existing building when the seismic isolation device is installed directly under the existing building. An excavation process for excavating directly under the existing building, a lower pile driving process for driving a lower pile in the ground facing the excavation space formed in the excavation process, and a lower pile facing the lower pile in the existing building. An upper pile installation step of installing an upper pile at a position, a jack installation step of installing a jack at the upper end of the lower pile and supporting the lower end of the upper pile with the jack, and the lower part in the excavation space. A seismic isolation device installation step of installing a seismic isolation device in the vicinity of the side pile and the upper pile, a seismic isolation device support step of lowering the jack to support the existing building with the seismic isolation device, and the jack. And a joint steel pipe installation step of installing a joint steel pipe on the outer periphery of the lower part of the upper pile and the upper part of the lower pile at a distance from the outer surface of the upper pile and the outer surface of the lower pile. It is characterized by comprising a mortar filling step of filling the inside of the joined steel pipe with mortar.

In the method of constructing the horizontal resistance structure of the existing building configured as described above, the bonded steel pipes are arranged outside the upper part of the lower pile and the lower part of the upper pile. The inside of the joined steel pipe is filled with mortar. Therefore, the hardened mortar connects the lower pile supported by the ground and the upper pile provided in the existing building, so that the horizontal resistance of the existing building can be secured.
The structure is such that the lower pile and the upper pile are connected in the vertical direction, and since the steel plate wall, brace, etc. are not installed in the excavation space as in the past, it does not hinder the loading and unloading of construction materials and the like.

Further, in the method for constructing the horizontal resistance structure of an existing building according to the present invention, the joined steel pipe is arranged in advance on the outside of the lower pile, and in the joined steel pipe installation step, the joined steel pipe is pulled up and inside. It is preferable to install the lower part of the upper pile and the upper part of the lower pile at a position where they are arranged.

In the method of constructing the horizontal resistance structure of the existing building configured in this way, if the joint steel pipe is arranged in advance on the outside of the lower pile and the joint steel pipe is pulled up, the lower part of the upper pile and the lower pile are inside. Workability is good because it is installed at the position where the upper part is placed.

According to the method for constructing the horizontal resistance structure of the existing building and the horizontal resistance structure of the existing building according to the present invention, it does not hinder the loading and unloading of construction materials and the like.

It is a vertical sectional view which shows the horizontal resistance structure of the existing building which concerns on one Embodiment of this invention. It is an enlarged view of part X of FIG. It is a figure which shows the construction method of the horizontal resistance structure of the existing building which concerns on one Embodiment of this invention, and is the figure which shows the jack installation process. It is a figure which shows the construction method of the horizontal resistance structure of the existing building which concerns on one Embodiment of this invention, and is the figure which shows the mortar filling process. It is a figure which shows the experimental apparatus which carried out using the horizontal resistance structure of the existing building which concerns on one Embodiment of this invention. It is a figure which shows the experimental result performed using the horizontal resistance structure of the existing building which concerns on one Embodiment of this invention.

The horizontal resistance structure of the existing building and the method of constructing the horizontal resistance structure of the existing building according to the embodiment of the present invention will be described with reference to the drawings.
First, the horizontal resistance structure of the existing building will be described. The horizontal resistance structure of an existing building is adopted during, for example, seismic isolation retrofit construction, in which the ground directly below the foundation of the existing building is excavated and a seismic isolation device is installed.
FIG. 1 is a vertical sectional view showing a horizontal resistance structure of an existing building according to an embodiment of the present invention. In FIG. 1, the upper pile and the lower pile are shown as a front view without being cut.
As shown in FIG. 1, in the existing building A, the mat slab D is excavated downward from the plinth B, the mat slab D is installed along the ground C, and the reinforcing slab E is installed along the lower surface of the plinth B. The horizontal resistance structure 100 of the existing building A is installed in the vicinity of the seismic isolation device 9 below the existing building A. In this embodiment, the seismic isolation devices 9 are installed on both sides in the horizontal direction.

The horizontal resistance structure 100 of the existing building A includes a lower pile 1, an upper pile 2, a bonded steel pipe 3, and a mortar 4 filled inside the bonded steel pipe 3.

A plurality of lower piles 1 are installed (placed) on the mat slab D and the ground C. In other words, the lower end pile 1 penetrates the mat slab D, the lower end (not shown) reaches the ground C, and the upper end 1u protrudes upward from the mat slab D. The lower pile 1 may be configured by connecting a plurality of steel pipes. In the present embodiment, the lower pile 1 is connected to, for example, a circular steel pipe (cylindrical steel pipe) having a diameter of 457.2 mm, a thickness of 12.7 mm, and a length of about 1000 mm by a mechanical joint (not shown) or the like.

A support plate 11 is provided at the upper end 1u of the lower pile 1. In the present embodiment, the support plate 11 is formed to have a thickness of, for example, about 12 mm.

The upper pile 2 is arranged vertically above the lower pile 1 so as to face each other. In other words, the upper pile 2 penetrates the reinforcing slab E, and the lower end 2b projects downward from the reinforcing slab E. In the present embodiment, for the upper pile 2, for example, a circular steel pipe having a diameter of 457.2 mm, a thickness of 12.7 mm, and a length of about 1000 mm is adopted. The lower pile 1 and the upper pile 2 are not limited to the circular steel pipe, but may be a square pipe or the like.

A support plate 21 is provided at the lower end 2b of the upper pile 2. In the present embodiment, the support plate 21 is formed to have a thickness of, for example, about 12 mm. A fixing portion 22 fixed to the foundation board B is provided at the upper end 2u of the upper pile 2.

FIG. 2 is an enlarged view of part X of FIG.
As shown in FIG. 2, the support plate 21 provided on the upper pile 2 has a circular shape in a plan view and has a diameter larger than that of the upper pile 2. In other words, the end portion (second protruding portion) 21e of the support plate 21 protrudes outward in the radial direction from the outer surface 2e of the upper pile 2. In the present embodiment, the support plate 21 has a circular shape having a radius of 10 mm larger than that of the upper pile 2. The support plate 11 provided on the lower pile 1 also has the same configuration as the support plate 11, has a circular shape in a plan view, and has a larger diameter than the lower pile 1. As shown in FIG. 1, there is a space (about 300 mm) or more between the support plate 11 of the lower pile 1 and the support plate 21 of the upper pile 2 so that the temporary receiving jack 6 (see FIG. 3) described later can be installed. Just leave it.

The joined steel pipe 3 is formed larger than the lower pile 1 and the upper pile 2 in a plan view. The joined steel pipe 3 extends from the lower part of the upper pile 2 to the upper part of the lower pile 1, and is arranged so as to cover the lower part of the upper pile 2 and the upper part of the lower pile 1. In the present embodiment, as the bonded steel pipe 3, for example, a circular steel pipe having a diameter of 558.8 mm, a thickness of 12.7 mm, and a length of about 850 mm is adopted. The joined steel pipe 3 is not limited to the circular steel pipe, and may be a square pipe. Further, a pair of semicircular steel pipes may be sandwiched between one side and the other side in a plan view of the upper pile 2 and the lower pile 1 and joined to each other to form a circular steel pipe.

The lengths L1 and L2 of the portions of the joined steel pipe 3 and the lower pile 1 and the upper pile 2 overlapping in the vertical direction are preferably ½ or more of the diameter L3 of the joined steel pipe 3. In the present embodiment, the length from the lower end of the joined steel pipe 3 to the upper surface of the support plate 11 of the lower pile 1 (the length from the upper end of the joined steel pipe 3 to the lower surface of the support plate 21 of the upper pile 2) is about 275 mm. Is.

It is preferable that the joined steel pipe 3 is arranged concentrically with the lower pile 1 and the upper pile 2. The diameter of the joined steel pipe 3 is preferably about 50 to 100 mm larger than the diameters of the lower pile 1 and the upper pile 2. Although the details will be described later, since the mortar 4 is injected from the gap between the joined steel pipe 3 and the lower pile 1, the inner surface 3i of the joined steel pipe 3 and the outer surfaces 1e and 2e of the lower pile 1 and the upper pile 2 are separated from each other. The gap is preferably 10 mm or more.

As shown in FIG. 2, on the inner surface 3i of the joined steel pipe 3, a rib (first protruding portion) 31 projecting inward in the radial direction and formed in an annular shape in a plan view is formed at the upper end portion. Ribs 31 are similarly formed at the lower end of the joined steel pipe 3. In the present embodiment, the upper rib 31 is located slightly below the upper end 3u of the bonded steel pipe 3, and the lower rib 31 is located slightly above the lower end. In the present embodiment, the rib 31 protrudes inward in the radial direction by about 6 mm from the inner surface 3i of the joined steel pipe 3.

As shown in FIG. 1, the mortar 4 is filled inside the joined steel pipe 3. In other words, between the inner surface 3i of the joined steel pipe 3 and the outer surface 2e of the upper pile 2, between the inner surface 3i of the joined steel pipe 3 and the outer surface 1i of the lower pile 1, and the support plate 21 and the lower pile of the upper pile 2. The space between the support plate 11 and the support plate 11 of 1 is filled with the mortar 4.

Next, a method of constructing the horizontal resistance structure 100 of the existing building A will be described.
After excavating the outer circumference of the existing building A and installing a girder (not shown), excavate directly under the existing building A (excavation process). An excavation space W is formed below the foundation B of the existing building A.

Next, the lower pile driving process is performed.
FIG. 3 is a diagram showing a method of constructing the horizontal resistance structure 100 of the existing building A, and is a diagram showing a jack installation process.
As shown in FIG. 3, the lower pile 1 is press-fitted at a desired location such as immediately below the pillar of the existing building A. A hydraulic jack (not shown) is installed on the lower surface of the foundation board B (bottom surface of the existing building A), and the lower pile 1 is press-fitted into the ground C by the hydraulic jack. At this time, it is preferable to pass the joined steel pipe 3 to the outside of the upper part of the lower pile 1. The leveling mortar B1 may be provided on the lower surface of the foundation board B.

Next, the upper pile installation process is performed.
As the press-fitting of the lower pile 1 progresses, the upper pile 2 is installed at a position facing the lower pile 1 on the lower surface of the foundation board B.

Next, the jack installation process is performed.
A temporary receiving jack 6 is installed on the support plate 11 (see FIG. 1) of the lower pile 1, and the upper pile 2 is temporarily supported by the temporary receiving jack 6.

Next, the seismic isolation device installation process is performed.
FIG. 4 is a diagram showing a method of constructing the horizontal resistance structure 100 of the existing building A, and is a diagram showing a mortar filling process.
As shown in FIG. 4, the mat slab D is installed along the ground C (see FIG. 3). Further, a reinforcing slab E is installed along the lower surface of the foundation board B. In the vicinity of the lower pile 1 and the upper pile 2, the lower foundation 91 is provided on the mat slab D, the seismic isolation device 9 is installed on the lower foundation, and the upper foundation 92 is provided on the seismic isolation device 9.

Next, the seismic isolation device support process and the jack removal process are performed.
After the temporary receiving jack 6 is brought down and the existing building A is supported by the seismic isolation device 9, the temporary receiving jack 6 is removed.

Next, the joint steel pipe installation process is performed.
The joint steel pipe 3 is installed so as to cover the lower part of the upper pile 2 and the upper part of the lower pile 1. At this time, a ring-shaped locking portion 36 is provided on the outer surface of the joined steel pipe 3, the chain block 37 with a hook is locked to the locking portion 36, and the chain block 37 is locked to the reinforcing slab E. The joined steel pipe 3 may be pulled up.
If the size of the joined steel pipe 3 is not larger than that of the upper pile 2 and the lower pile 1 in a plan view, the upper pile 2 and the lower pile 1 can be arranged inside the joined steel pipe 3. 2 and the outer periphery of the lower pile 1 may be cut.

Next, a mortar filling step is performed.
The inside of the joined steel pipe 3 is filled with mortar 4.
At the lower end of the joined steel pipe 3, a formwork (not shown) having a shape corresponding to the gap between the inner surface 3i of the joined steel pipe 3 and the outer surface 1e of the lower pile 1 is installed. At the upper end of the joined steel pipe 3, the mortar 4 is injected through the gap between the inner surface 3i of the joined steel pipe 3 and the outer surface 2e of the upper pile 2. As the mortar 4 hardens, the upper pile 2 and the lower pile 1 are connected via the mortar 4.
After installing the seismic isolation devices 9 at all the planned installation locations, the lower pile 1 and the upper pile 2 are cut.

(Experimental example)
Next, an experimental example performed on the horizontal resistance structure 100 of the existing building A shown above will be described.
In order to confirm the horizontal resistance force and the joint part strength of the horizontal resistance structure 100 of the existing building A, a force test of the joint part was carried out using a full-scale test piece. Assuming that a seismic force acts on the seismic isolation layer, positive and negative alternating shear forces were applied to the test piece, and the mechanical behavior was confirmed.

FIG. 5 is a diagram showing an experimental apparatus performed using the horizontal resistance structure 100 of the existing building A.
The shape and dimensions of the test piece and the applying device are shown in FIG. The test body is a model of a reinforcing slab, a steel pipe pile (upper pile 2), a steel pipe for joining (joined steel pipe 3), and a filled mortar (mortar 4) (joint portion), and is set upside down. .. A 355.6 mm × 9.5 mm (STK400) annular steel pipe with a cross-sectional view was used for the steel pipe pile, and a 457.2 mm × 9.5 mm (STK400) annular steel pipe with a cross-sectional view was used for the joining steel pipe. The bonding in the steel, the pre-mix type mortar _{(J 14} funnel test 8 ± 2 seconds, approximately compressive strength 60N / mm ²⁾ was filled with. The force point was the position of the reaction force point of the moment distribution generated in the steel pipe pile when the upper and lower steel pipe piles were rigidly contacted.

FIG. 6 is a diagram showing the results of an experiment conducted using the horizontal resistance structure 100 of the existing building A.
FIG. 6 shows the relationship between the shear force and the deformation angle of the steel pipe pile obtained from the experimental results. The maximum yield strength of the test piece was determined by the local buckling of the steel pipe pile. Local buckling was observed at the embedded end of the steel pipe pile, and the filled mortar in the joint was sound with cracks until the final state. In addition, the initial rigidity of the test piece should correspond well with the calculated value (see the steel structure joint design guideline) obtained for the embedded column base type steel pipe pile, even if the horizontal resistance structure 100 of the existing building A shown above is not present. Shown. As shown in FIG. 6, when the interlayer deformation angle of the seismic isolation layer generated during an earthquake during construction is 1/100 (0.1 rad), one steel pipe pile is provided by the horizontal resistance structure 100 of the existing building A shown above. It was confirmed that a horizontal resistance of 400 kN was obtained per hit. The horizontal resistance can be improved by increasing the cross section of the steel pipe pile. For example, if a circular steel pipe having a thickness of 457.2 mm × 12.8 mm is used as the steel pipe pile, a horizontal resistance force of 650 kN can be secured per steel pipe pile with an interlayer deformation angle of 1/100 (0.1 rad).
In the actual design, the horizontal resistance is calculated by the following procedure. (1) Set the inter-story deformation angle of the seismic isolation layer that occurs during an earthquake. (2) Calculate the rigidity of the steel pipe pile obtained as an embedded column base type steel pipe pile without considering the joint. (3) Based on the calculated rigidity, the horizontal resistance forces for the number of steel pipe piles to which the horizontal resistance structure 100 of the existing building A shown above is applied are totaled.

In the method of constructing the horizontal resistance structure 100 of the existing building A and the horizontal resistance structure 100 of the existing building A configured in this way, the joint steel pipe 3 is arranged outside the upper part of the lower pile 1 and the lower part of the upper pile 2. Has been done. The inside of the joined steel pipe 3 is filled with mortar 4. Therefore, the hardened mortar 4 connects the lower pile 1 supported by the ground C and extending upward and the upper pile 2 supported by the existing building A and extending downward, thus ensuring the horizontal resistance of the existing building A. be able to.

Further, since the lower pile 1 and the upper pile 2 are connected in the vertical direction and the steel plate wall, the brace, etc. are not installed as in the conventional case, it does not hinder the loading and unloading of construction materials and the like.

Further, since the rib 31 protruding inward is provided on the inner surface of the joined steel pipe 3 and the rib 31 is embedded in the mortar 4, the joined steel pipe 3 is prevented from falling off.

Further, the end of the support plate 11 provided on the lower pile 1 and the upper pile 2, protruding outward in the radial direction from the outer surfaces of the lower pile 1 and the upper pile 2, and provided at the upper end of the joined steel pipe 3. The rib 31 is arranged above the support plate 11. Therefore, the end portion of the support plate 11 supports the hardened mortar 4, and the rib 31 of the joint steel pipe 3 receives a reaction force from the end portion of the support plate 11 via the mortar 4, so that the joint steel pipe 3 falls off. Is further suppressed.

Further, since the length of each of the joint steel pipe 3, the lower pile 1 and the upper pile 2 overlapping in the vertical direction is ½ or more of the diameter of the joint steel pipe 3, the horizontal resistance of the existing building A Power can be reliably secured.

Further, if the joined steel pipe 3 is arranged in advance on the outer periphery of the lower pile 1, and the joined steel pipe 3 is pulled up, it is installed at a position where the lower portion of the upper pile 2 and the upper portion of the lower pile 1 are arranged inside. Therefore, workability is good.

Further, when the upper pile 2 and the lower pile 1 are eccentric in a plan view, in the configuration in which the upper pile 2 and the lower pile 1 are bolted together, the upper pile 2 and the lower pile 1 are bolted. Difficult to connect. In the present invention, the upper pile 2 and the lower pile 1 are covered with a joint steel pipe 3 larger than the upper pile 2 and the lower pile 1, and the inside of the joint steel pipe 3 is filled with the mortar 4. Therefore, the upper pile 2 Even if the lower pile 1 and the lower pile 1 are eccentric in a plan view, they can be constructed as long as they can be covered by the joined steel pipe 3.

The assembly procedure shown in the above-described embodiment, or various shapes and combinations of the constituent members are examples, and various changes can be made based on design requirements and the like without departing from the gist of the present invention.

For example, in the embodiment shown above, the joint steel pipe 3 is provided with a first protruding portion, and the lower pile 1 and the upper pile 2 are provided with a second protruding portion, but the present invention is not limited to this. , The first protrusion and the second protrusion may not be provided. Alternatively, although the first protruding portion is formed in an annular shape in a plan view, it may be formed so as to project inward from the inner surface of the joined steel pipe 3 and may be formed discontinuously in the circumferential direction.

1 ... Lower pile 2 ... Upper pile 3 ... Joint steel pipe 4 ... Mortar 9 ... Seismic isolation device 11 ... Support plate 21 ... Support plate 21e ... End of support plate (second protrusion)
22 ... Fixed part 31 ... Rib (first protruding part)
100 ... Horizontal resistance structure A ... Existing building B ... Foundation C ... Ground D ... Mat slab E ... Reinforcing slab W ... Excavation space

Claims (6)

It is a horizontal resistance structure that supports the existing building when the seismic isolation device is installed directly under the existing building.
A lower pile that is placed near the seismic isolation device, is supported by the ground, and extends upward.
An upper pile that is arranged above the lower pile and is supported by the existing building and extends downward.
A bonded steel pipe extending in the vertical direction and having an upper portion of the lower pile and a lower portion of the upper pile arranged inside.
A horizontal resistance structure of an existing building, which comprises a mortar filled inside the joined steel pipe. The horizontal resistance structure of an existing building according to claim 1, wherein a first protruding portion projecting inward is provided on the inner surface of the joined steel pipe. A second projecting portion that projects outward is provided on the outer surface of at least one of the lower pile and the upper pile.
The horizontal resistance structure of an existing building according to claim 2, wherein the first protruding portion is arranged above the second protruding portion. Claims 1 to 3 characterized in that the length of the vertically overlapping portion of the joined steel pipe, the lower pile, and the upper pile is ½ or more of the diameter of the joined steel pipe. Horizontal resistance structure of the existing building described in any one of the above. It is a method of constructing a horizontal resistance structure of an existing building that supports the existing building when installing a seismic isolation device directly under the existing building.
The excavation process to excavate directly under the existing building and
A lower pile driving process in which a lower pile is driven in the ground facing the excavation space formed in the excavation process, and a lower pile driving process.
The upper pile installation process of installing the upper pile at a position facing the lower pile in the existing building,
A jack installation process in which a jack is installed at the upper end of the lower pile and the lower end of the upper pile is supported by the jack.
A seismic isolation device installation process for installing a seismic isolation device in the vicinity of the lower pile and the upper pile in the excavation space,
A seismic isolation device support process in which the jack is lowered to support the existing building with the seismic isolation device,
The jack removal process for removing the jack and
A joining steel pipe installation step of installing a joining steel pipe at the lower part of the upper pile and the outer circumference of the upper part of the lower pile at a distance from the outer surface of the upper pile and the outer surface of the lower pile.
A method for constructing a horizontal resistance structure of an existing building, which comprises a mortar filling step of filling the inside of the joined steel pipe with mortar. The bonded steel pipe is arranged in advance on the outside of the lower pile.
The existing building according to claim 5, wherein in the joint steel pipe installation step, the joint steel pipe is pulled up and installed at a position where the lower portion of the upper pile and the upper portion of the lower pile are arranged inside. How to build a horizontal resistance structure.

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