JP6707382B2 - Seismic isolation work method - Google Patents

Description

The present invention relates to a seismic isolation construction method, and more particularly, to a construction method for replacing a seismic isolation device installed in an existing building or a construction method for installing a seismic isolation device in an existing building.

Laminated rubber is mainly used as a seismic isolation device for seismic isolation of buildings. The rubber member of the laminated rubber may deteriorate over time, and when the deterioration occurs, it is necessary to replace the laminated rubber.

When carrying out the replacement work of the laminated rubber, it is necessary to carry out the work while the resident of the building is present, and it is necessary to carry out the work while ensuring the seismic isolation performance of the building under construction. In order to satisfy these conditions, in Patent Document 1, a sliding bearing is provided at the lower end of the jack that temporarily receives the load from the existing column when the seismic isolation device is replaced, so that the seismic isolation is achieved even when supported by the jack. Maintaining function is disclosed.

JP, 2008-163636, A

However, seismically isolated buildings are often super high-rise buildings. This is because a building that is taller than the bottom surface is likely to generate a falling moment, and if the seismic isolation device reduces the seismic motion input to the building, the falling moment can be suppressed.

In a super high-rise building, the pillar on the lowest floor supports a large axial force, and one pillar, that is, one seismic isolation device often supports 20 MN or more.

However, a general dry bracket used for temporarily receiving the axial force of a pillar is made of a steel material, and a shape steel can support a load of about 10 MN. When a load larger than this is applied, the shaped steel cannot support the load, and the ends are deformed. Although it is possible to make a bracket of shaped steel capable of supporting a load of 20 MN or more, the bracket becomes too large and heavy, which makes it difficult to carry and install.

In view of the above points, the present invention is capable of reducing the size and weight as compared with the case of being made of shaped steel, and a column capable of supporting a large axial force applied to an existing column. It is an object of the present invention to provide a construction method using a temporary axial force receiving structure.

A first aspect of the present invention is located below a pillar of an existing building and is installed between an upper structure made of concrete integrated with the pillar and a lower structure separated from the upper structure. A seismic isolation work method for exchanging a seismic isolation device, wherein a pair of concrete brackets sandwiching the pillar from both sides are provided on the outside of the pillar at protrusions located on both outer sides in a direction orthogonal to the sandwiching direction. Passing through each of the tension rods so as to pass therethrough, and connecting the tension rods in a state in which a tension force is applied; and a step of additionally hammering concrete into the upper structure to form a hammering portion, Installing a jack between the additional striking part and the lower structure, releasing the connection between the seismic isolation device and one of the lower structure or the upper structure, and extending the jack A step of disconnecting the seismic isolation device from the other of the lower structure or the upper structure, replacing the seismic isolation device with a new seismic isolation device, and shortening the jack A step of connecting the new seismic isolation device to the upper structure and the lower structure, and a step of removing the pair of brackets and the tension rod member, each bracket including the protrusion It is characterized in that it has a notch portion recessed toward the column between a direction orthogonal to the sandwiching direction.

A second aspect of the present invention is to secure an upper structure which is located below a pillar of an existing building and is made of concrete integrally with the pillar, the upper structure, and a portion for inserting a seismic isolation device in the pillar. The upper structure is a seismic isolation work method to install a seismic isolation device between the separated lower structure, a pair of concrete brackets sandwiching the pillar from both sides, the direction orthogonal to the sandwiching direction. Inserting the tension rods into the protrusions located on both outer sides so as to pass through the outside in the direction orthogonal to the sandwiching direction of the column, and connecting the tension rods in a state in which a tension force is applied. A step of forming an additional-pushing portion by additionally piling concrete on the upper structure, a step of installing a jack between the additional-pushing portion and the lower structure, a step of extending the jack, Inserting a seismic isolation device between the upper structure and the lower structure, shortening the jack, and connecting the seismic isolation device to the upper structure and the lower structure. And a step of removing the pair of brackets and the tension rod member, wherein each of the brackets has a notch recessed toward the pillar between a direction orthogonal to the sandwiching direction of the protrusion, and the protrusion. It is characterized by having a connecting portion for connecting the portions in a direction orthogonal to the sandwiching direction .

According to the first invention or the second invention of the present invention, a pair of concrete brackets for sandwiching a pillar of an existing building from both sides are provided with protrusions located at both outer side portions in a direction orthogonal to the sandwiching direction. The tension rods are inserted so as to pass through the outside in the direction orthogonal to the sandwiching direction, and the tension rods are connected in a state in which a tension force is applied. Each bracket has a notch recessed toward the column between the protrusions located on both outsides in the direction orthogonal to the sandwiching direction.

For this reason, in each bracket, the protruding portion, through which the tension rod member that applies the tension force is inserted, can secure the length in the sandwiching direction so that the compression force due to the tension force does not cause deformation and damage. It is possible. Then, the compression force due to this tension force is obliquely transmitted to each bracket from the protruding portion toward the center of the contact surface with the existing column. Therefore, it is possible to reduce the weight of the bracket by forming a notched portion that is recessed toward the column in a portion between the protruding portions that is out of the transmission range and is less affected by the compression force. Further, since each bracket is made of concrete, the degree of freedom of shape is high as compared with the conventional case where the bracket is made of a steel material.

For these reasons, it is easy for each bracket to have a shape capable of withstanding the compressive force as described above and reducing the weight. Therefore, it is possible to simplify the work of installing a member that transmits the axial force of the pillar to the jack using these brackets. Further, the connecting portion can prevent the protruding portion of the bracket from being deformed to open outward in the direction orthogonal to the sandwiching direction.

In the first invention or the second invention of the present invention, it is preferable to include a step of attaching a reinforcing plate so as to extend over the lower surface of the upper structure and the lower surface of the additional striking portion.

In this case, it is possible to reinforce the additional striking portion connected above the jack that generates the pressure transmitted to the pillar via the pair of pillars by the reinforcing plate.

Further, in the first invention or the second invention of the present invention, between the pair of brackets, it is located outside in a direction orthogonal to the sandwiching direction of the pillar, and is made of concrete into which the tension rod member is inserted. It is preferable to provide the step of providing the auxiliary bracket of.

In this case, the auxiliary bracket provided between the brackets can prevent the bracket from being deformed in the sandwiching direction.

Further, in the first invention or the second invention of the present invention, a tension force is obtained by inserting an auxiliary tension rod member that connects the two protrusions in a direction orthogonal to the sandwiching direction to the two protrusions of each bracket. It is preferable to include a step of applying

In this case, since the tension force is applied by the auxiliary tension rod member, it is possible to prevent the protruding portion of the bracket from being deformed to open outward in the direction orthogonal to the sandwiching direction.

Further, in the first invention or the second invention of the present invention, each of the brackets is divided in the vertical direction, and the tension bar member is inserted into each of the divided brackets, and the protruding portion of the upper bracket is inserted. The length is preferably shorter than the length of the lower protrusion of the bracket.

In this case, since each bracket is divided in the vertical direction, it is possible to reduce the size and weight of each bracket, and it is possible to facilitate the work such as transportation and installation of these brackets.

Further, in the first or second aspect of the present invention, that have a connection portion to which the respective bracket is connected in a direction perpendicular to the direction to sandwich the said projecting portions.

Thus , the connecting portion can prevent the protruding portion of the bracket from being deformed to open outward in the direction orthogonal to the sandwiching direction.

Further, in the first invention or the second invention of the present invention, it is preferable that an auxiliary connection member that connects the protrusions in a direction orthogonal to the sandwiching direction is attached to the bracket by connection with the tension rod member.

In this case, it is possible to prevent the protrusion of the bracket from being deformed to open outward in the direction orthogonal to the sandwiching direction due to the restraint by the auxiliary connecting member.

The front view explaining the seismic isolation construction method which concerns on embodiment of this invention. II-II sectional view taken on the line of FIG. The side view which shows the state which replaces a seismic isolation device using a pillar axial force temporary receiving structure. Sectional drawing which shows the modification of a pillar axial force temporary receiving structure.

A structure for temporarily receiving the axial force of a column (hereinafter, referred to as a column axial force temporary receiving structure) used in the seismic isolation work method according to the embodiment of the present invention will be described with reference to FIGS. 1 to 3.

Here, the column axial force temporary receiving structure temporarily receives the axial force of the pillars (hereinafter referred to as the existing columns) 11 of the existing building 10 during the work of replacing the seismic isolation device 20 of the existing building 10. The case applied to the structure will be described. More specifically, a structure for temporarily receiving the axial force of the existing pillar 11 on the first floor in order to replace the seismic isolation device 20 installed in the underground pit will be described as an example.

However, the column axial force temporary receiving structure of the present invention may be applied to a structure for temporarily receiving the axial force of an existing column during the construction of newly installing a seismic isolation device in an existing building.

The seismic isolation device 20 is, for example, an isolator using laminated rubber. However, the seismic isolation device 20 is not limited to this, and may be any device that achieves seismic isolation by any of the conventionally used methods.

Here, in the seismic isolation device 20, the flange plate 21 existing at the upper end thereof is provided on the lower surface of the upper foundation 12 of the existing building 10 by a bolt or the like not shown on the base plate 13 integrated with the upper foundation 12. It is detachably connected. The upper foundation 12 is located below the existing pillars 11, is integrated with the existing pillars 11 and is made by solidifying concrete, and corresponds to the upper structure of the present invention.

Then, the seismic isolation device 20 has a flange plate 22 existing at the lower end thereof removable on the upper surface of the foundation 14 of the existing building 10 by a bolt (not shown) or the like on a base plate 15 formed integrally with the foundation 14. Is linked to. The foundation 14 is formed by separating concrete from the upper foundation 12 and solidifying the concrete, and corresponds to the upper structure of the present invention.

Then, a plurality of jacks 30 are installed on the upper surface of the foundation 14 around the seismic isolation device 20 via sliding plates (sliding bearings) 31 and the like. In the present embodiment, the number of jacks 30 installed is 6, but the number is not limited to this. The number of jacks 30 is determined according to the vertical load (column axial force) that acts on one existing column 11 and the load that one jack 30 can bear. When the number of jacks 30 is large and the jacks 30 cannot be arranged only by the existing foundation 14, the width of the foundation 14 may be widened by additionally striking concrete in the width direction of the foundation 14.

These jacks 30 are installed between the upper foundation 12 and the foundation 14. When the upper foundation 12 does not exist above the jack 30, concrete is additionally struck on the side surfaces of the upper foundation 12 and the beam below the first floor so that the upper foundation 12 and the beam below the first floor can be integrated into the front-rear direction. An extended additional striking portion 16 is formed. Although not shown, an appropriate number of height adjusting plates are inserted into the gap between the jack 30 and the lower surface of the upper base 12 or the additional striking portion 16 to eliminate the gap between them.

A reinforcing plate 17 integrated with the additional striking portion 16 may be provided on the lower surface of the additional striking portion 16, and the reinforcing plate 17 may be joined to the base plate 13 integral with the upper foundation 12 by welding or the like. preferable.

Further, when the shear stress of the upper foundation 12 is insufficient, the reinforcing plate 17 made of a steel plate or the like may be adhered to the side surface of the upper foundation 12 in the width direction with an epoxy or the like for reinforcement.

The column axial force temporary receiving structure is configured such that a pair of PC (precast concrete) brackets 41 are sandwiched from both sides of the existing column 11 and these PC brackets 41 are connected by a PC steel rod 42. The PC bracket 41 corresponds to the bracket of the present invention, and the PC steel rod 42 corresponds to the tension rod material of the present invention. Here, the cross section of the existing pillar 11 is a quadrangle. The reinforcing bars inside the existing columns 11 are omitted in the drawing. Hereinafter, the direction in which the PC bracket 41 sandwiches the existing pillar 11 will be referred to as the front-back direction, and the direction orthogonal to the sandwiching direction will be described as the width direction.

A tension force is applied to the PC steel rods 42, and a frictional force between the surfaces of the existing columns 11 and the PC brackets 41 that are in close contact with each other acts, so that the column axial force acting on the existing columns 11 is passed through the PC brackets 41. Can be transmitted to the jack 30.

The PC bracket 41 is a concrete precast member, and is preferably made of an ultrahigh strength fiber reinforced mortar material. The ultra-high strength fiber reinforced mortar material is, for example, Ductal (registered trademark) or Saxem (registered trademark).

The ultra-high-strength mortar-based material has a strength of about ½ but a weight of about ⅓ as compared with steel materials. Further, a member made of an ultrahigh-strength mortar-based material has a greater degree of freedom in designing the shape than a member made of steel. Therefore, the PC bracket 41 made of the ultra-high-strength mortar-based material can be easily formed into an optimum shape for transmitting the axial force of the existing column 11 to the jack 30, as compared with the conventional bracket made of steel. While being lightweight, it is possible to support a large column axial force.

Each of the PC brackets 41 has a contact surface 41a that comes into contact with the surface of the existing pillar 11 in the front-rear direction, here the surface of the existing building 10 on the beam (not shown) side. The PC bracket 41 has a pressing portion 41b having a predetermined thickness in the direction away from the existing column 11 in the front-back direction from the contact surface 41a. The thickness of the pressing portion 41b is set so that the PC bracket 41 is not damaged or deformed even when the PC bracket 41 is pressed against the existing column 11 by the tension of the PC steel rod 42.

Then, from both outer sides in the width direction of the pressing portion 41b, projecting portions 41c projecting in a direction away from the existing column 11 in the front-rear direction are extended. A sheath tube 41d is embedded in each of the protrusions 41c so as to penetrate in the front-rear direction. Here, in each of the PC brackets 41, a plurality of stages of sheath tubes 41d are embedded in the protrusion 41c side by side in the vertical direction. The sheath tube 41d is made of resin such as vinyl chloride, for example.

One PC steel rod 42 is inserted into the sheath tubes 41d that are respectively embedded in the front protrusions 41c of the pair of PC brackets 41, and the sheaths that are respectively embedded in the rear protrusions 41c of the pair of PC brackets 41 are inserted. Another PC steel rod 42 is also inserted through the pipe 41d. Then, a nut 43 is screwed into and fixed to the tip of the PC steel rod 42 projecting in the front-rear direction from each of the PC brackets 41.

Due to this tightening force, a tension force is applied to the PC steel rod 42, and a compressive force is applied to the existing column 11 via the pair of PC brackets 41. By this compression force, the existing column 11 and the PC bracket 41 are brought into close contact with each other, and pressure is applied to the contact surface 41a to press the contact surface 41a, thereby increasing the frictional force between the closely contacted surfaces.

In this manner, the PC steel rod 42 is tightly connected, so that a compressive force acts on the PC bracket 41. The width of the protruding portion 41c, which is the portion on which the compressive force acts, can withstand the compressive force due to the tight binding of the PC steel rod 42, and is a nut necessary for fixing the end portion of the PC steel rod 42. The width required for attaching 43 or the like is secured.

The length (depth length) of the protrusion 41c of the PC bracket 41 in the front-rear direction is a length capable of transmitting the column axial force from the existing column 11 to the jack 30 via the upper foundation 12 or the additional striking unit 16. Is secured. Here, the protruding portion 41c of the PC bracket 41 extends to the vicinity of the central position of the jack 30 in a top view.

Further, each PC bracket 41 is provided with a notch 41e recessed from the beam side toward the existing column 11 side between the two protruding portions 41c. The cutout portion 41e may be formed over the entire vertical direction of the PC bracket 41, but in the present embodiment, it is formed only in the intermediate portion in the vertical direction.

The cross section of the notch 41e is trapezoidal here. By providing such a notch portion 41e, the weight of the PC bracket 41 can be reduced.

However, due to the tension force from the PC steel rod 42, the protruding portion 41c of the PC bracket 41 is deformed so as to spread outward in the width direction, and the contact surface 41a is curved in a bow shape. Since the portion that comes into contact with 41 is only in the vicinity of the corner portion of the existing column 11, the column axial force cannot be sufficiently transmitted, or the corner portion of the existing column 11 and the PC bracket 41 may be damaged. Therefore, it is preferable to provide a connecting portion 41f that connects the protruding portion 41c in the width direction and to provide a portion where the cutout portion 41e is not formed.

The end of the notch 41e on the side of the existing column 11 extends a straight line in the front-back direction by the thickness of the pressing portion 41b in the direction of 45° from the center of the contact surface 41a in the direction away from the existing column 11 in the front-back direction. It is almost the same as the width-direction length when it is made. When the end of the notch 41e on the side of the existing column 11 is widened by this, it becomes difficult to transmit the tension force of the PC steel rod 42 to the existing column 11 via the protrusion 41c of the PC bracket 41. On the other hand, if the end of the notch portion 41e on the side of the existing column 11 is made narrower than this, the tension of the PC steel rod 42 can be easily transmitted to the existing column 11, but the weight of the PC bracket 41 increases.

Then, in the present embodiment, the inclination of the side surface in the width direction of the cutout portion 41e is such that the end of the protruding portion 41c and the flat surface portion of the cutout portion 41e on the side of the existing column 11 are connected by a flat surface. .. In this way, the cross section of the cutout portion 41e is trapezoidal as described above. However, the cross section of the cutout portion 41e is not limited to the trapezoidal shape, and there is the disadvantage that the weight increases, but a shape smaller than this trapezoidal shape may be used.

In order to transmit a large pillar axial force through the PC bracket 41, a large frictional force is required between the existing pillar 11 and the PC bracket 41, and the PC bracket 41 has a certain length in the vertical direction. Is preferred. However, if the vertical length of the PC bracket 41 is increased, the individual PC brackets 41 become heavier and the volume thereof becomes bulky, which makes transportation and installation difficult, which is not preferable.

Therefore, in the present embodiment, each PC bracket 41 is divided into an upper part and a lower part and is configured by a lower PC bracket 41A and an upper PC bracket 41B. Further, the upper PC bracket 41B has a shorter length in the front-rear direction of the projecting portion 41c than the lower PC bracket 41A.

Although not shown, it is also preferable to provide a connecting member that connects the lower PC bracket 41A and the upper PC bracket 41B. In this case, a plate or the like may be installed from a steel plate or the like on the side surfaces of these PC brackets 41A and 41B, and these plates or the like may be joined by bolts or the like.

Further, as shown in FIG. 4, the column axial force temporary receiving structure may include an auxiliary PC steel rod 44 that tightly connects the vicinity of the tips of the two protruding portions 41 c of the PC bracket 41. The auxiliary PC steel rod 44 corresponds to the auxiliary tension rod material of the present invention, and is provided to prevent the deformation of the PC bracket 41.

Here, the auxiliary PC steel rod 44 is provided in a portion where the connecting portion 41f does not exist. In this case, a sheath tube 41g is embedded in each of the protrusions 41c in the width direction, and an auxiliary PC steel rod 44 is provided so as to pass through the sheath tubes 41g. Then, the nut 43 is screwed into and fixed to the tip of the auxiliary PC steel rod 44 protruding in the width direction from each of the PC brackets 41. By this tightening force, a tension force is applied to the auxiliary PC steel rod 44, and it is possible to prevent the protruding portion 41c from being deformed so as to open outward.

Although not shown, the auxiliary PC steel rod 44 may be provided so as to penetrate the inside of the connecting portion 41f in the width direction. In this case, the sheath tube may be continuously embedded in the width direction of the protruding portion 41c and the connecting portion 41f, and the auxiliary PC steel rod 44 may be provided so as to pass through the sheath tube.

Further, the column axial force temporary receiving structure may include an auxiliary bracket 45 installed on a surface of the existing pillar 11 that is orthogonal to the surface on which the PC bracket 41 is installed. The auxiliary bracket 45 has a length slightly shorter than the gap between the pair of PC brackets 41 in the front-rear direction, and is arranged so as to be sandwiched between the PC brackets 41. The presence of the auxiliary bracket 45 makes it possible to suppress the deformation of the PC bracket 41.

The auxiliary bracket 45 is a concrete precast member and may be made of an ultra-high strength fiber-reinforced mortar material, or may be a normal or high-strength mortar material.

Here, a sheath tube 45a is embedded in the auxiliary bracket 45 in the front-rear direction, and a PC steel rod 42 for fastening the PC bracket 41 is inserted into the sheath tube 45a. The width of the auxiliary bracket 45 is substantially the same as the width of the PC bracket 41 protruding from the widthwise outer side of the existing pillar 11.

Furthermore, the column axial force temporary receiving structure may include an auxiliary connecting plate 47 that tightly connects the front end portions of the two front and rear protruding portions 41c of the PC bracket 41. The auxiliary connecting plate 47 corresponds to the auxiliary connecting member of the present invention and is provided to prevent the deformation of the PC bracket 41.

The auxiliary connecting plate 47 is made of a steel plate in which through holes are formed in the vicinity of both ends, and the PC steel rods 42 protruding from the tips of the protruding portions 41c are penetrated into the through holes, and the PC steel rods 42 are attached by nuts 43 or the like. It is installed by concluding. Since the auxiliary connecting plate 47 is fixed by the tension force of the PC steel rod 42, even if there is a difference in diameter between the through hole of the auxiliary connecting plate 47 and the PC steel rod 42, the deviation is unlikely to occur.

The auxiliary connecting plates 47 may be installed on all the PC steel rods 42, but only the required number of them may be installed to prevent the deformation of the PC bracket 41.

Although all of the auxiliary PC steel rod 44, the auxiliary bracket 45, and the auxiliary connecting plate 47 are shown in FIG. 4, any one kind may be used, or a plurality of kinds may be used in combination.

Hereinafter, replacement work of the seismic isolation device for the existing building according to the embodiment of the present invention using the above-described column axial force temporary receiving structure will be described with reference to FIGS. 1 to 4.

First, in the upper foundation 12 in which the seismic isolation device 20 is inserted between the lower surface and the foundation 14, concrete is additionally overstretched in the front-rear direction so that the jack 30 is arranged between the foundation 30 and the foundation 14. Then, the step of forming the additional hammering portion 16 is performed.

Each additional striking part 16 is formed by installing a formwork (not shown), striking the post-installed anchors to the upper foundation 12 and the beam below the first floor and arranging the bar, placing concrete and then curing it. To do. At this time, the upper surface of the additional striking portion 16 is brought into close contact with the lower end of the first floor slab 19. When the reinforcing plate 17 is installed, the reinforcing plate 17 forms a part of a mold for forming the additional striking portion 16, and is joined to the base plate 13 integrated with the lower surface of the upper base 12 by welding or the like. ..

Next, if necessary, with reference to FIG. 4, the reinforcing plate 18 is also adhered to the side surface of the upper base 12 by an adhesive such as epoxy.

Next, the slide plate 31 and the like are installed on the foundation 12 as disclosed in Patent Document 1 above.

Next, the pair of PC brackets 41 is inserted into the sheath tube 41d through the PC steel rod 42, and is sandwiched from the front-rear direction of the existing column 11 to apply a tension force to connect them. Note that, as shown in FIG. 4, when the auxiliary bracket 45 is used, the PC steel rod 42 is also inserted through the sheath tube 45 a of the auxiliary bracket 45.

When the auxiliary PC steel rod 44 is used, the auxiliary PC steel rod 44 is inserted through the sheath tube 41g embedded in the two protruding portions 41c of each PC bracket 41, and tightened by applying a tension force.

Next, the step of installing the jack 30 between the foundation 14 and the additional striking portion 16 is performed.

Next, a process of releasing the connection between the flange plate 21 existing at the upper end of the seismic isolation device 20 and the base plate 13 integrated with the upper foundation 12 is performed. Instead of this releasing step, a step of releasing the connection between the flange plate 22 existing at the lower end portion of the seismic isolation device 20 and the base plate 15 formed integrally with the foundation 14 may be performed.

Next, a process of extending the jack 30 a little, for example, several mm and stopping it in that state is performed. In this case, all the jacks 30 related to one existing pillar 11 are simultaneously extended. At this time, all the jacks 30 related to the plurality of adjacent existing columns 11 may be extended at the same time.

Next, a step of releasing the connection that was not released in the releasing step is performed. That is, in the releasing step, when the connection between the flange plate 21 and the base plate 13 is released, the connection between the flange plate 22 and the base plate 15 is released, and when the connection between the flange plate 22 and the base plate 15 is released, The connection between the flange plate 21 and the base plate 13 is released.

Next, a step of replacing the seismic isolation device 20 with a new seismic isolation device is performed. At this time, the replacement work is performed using the slide plate 31 and the like.

Next, the step of shortening the jack 30 and returning it to the original state is performed.

Next, the flange plate 21 existing at the upper end of the new seismic isolation device and the base plate 13 integrated with the upper foundation 12, and the flange plate 22 and the foundation 14 existing at the lower end of the new seismic isolation device, The step of connecting the integrally formed base plates 15 to each other is performed.

Finally, the step of removing the PC bracket 41, the PC steel rod 42, the jack 30 and the like is performed. In addition, you may use these removed members again with respect to the other existing pillar 11 of the same existing building 10.

As described above, according to the embodiment of the present invention, in the existing pillar 11, the pair of PC brackets 41 connected to each other in a state in which the tension force is applied by the PC steel rod 42 is provided on both side surfaces of the existing pillar 11. It is fixed so as to be sandwiched and pressed. Each PC bracket 41 has a notch 41e recessed toward the pillar between the widthwise directions of the protrusions 41c located outside the widthwise direction.

Therefore, in each PC bracket 41, the projection 41c through which the PC steel rod 42 that applies the tension is inserted has a length in the front-rear direction so that the compression force due to the tension does not act to cause deformation, damage, or the like. It is possible to secure.

Further, the compressive force due to this tension force is obliquely transmitted to each PC bracket 41 from the protruding portion 41c toward the center of the contact surface 41a with the existing column 11. Therefore, the weight of the PC bracket 41 is reduced by forming a notch recessed toward the column in a portion between the protrusions 41c that is out of the transmission range and is less affected by the compression force. Furthermore, since each PC bracket 41 is made of an ultrahigh-strength fiber-reinforced mortar material, the degree of freedom of shape is high as compared with the conventional case of being made of a steel material.

For these reasons, each of the PC brackets 41 can easily have a shape capable of withstanding the compressive force as described above and reducing the weight.

Although the embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited thereto.

For example, the case of using the column axial force temporary receiving structure of the present invention for the construction of replacing the seismic isolation device of the existing building has been described. However, the temporary column axial force receiving structure of the present invention can be used not only for such work, but also for work such as newly installing a seismic isolation device in an existing building.

In this case, it is necessary to secure a portion into which the seismic isolation device is inserted, but the column axial force temporary receiving structure of the present invention may be applied to an existing column located above that portion.

Moreover, the construction when the seismic isolation device 20 is inserted between the upper foundation 12 and the foundation 14 has been described. However, the column axial force temporary receiving structure of the present invention can be applied not only to such a construction but also to the case where the seismic isolation device is inserted between the columns of the intermediate floor. In this case, the column axial force temporary receiving structure of the present invention may be installed on the existing column existing above the portion where the seismic isolation device is inserted.

The temporary column axial force receiving structure of the present invention may be used only for the existing column 11 having a large column axial force, and a conventional bracket made of shaped steel or the like may be used for the existing column having a small column axial force.

Further, when the target is a column on the outer periphery of an existing building, it is structurally desirable that each PC bracket 41 is installed in the direction in which the beam exists under the floor on which it is installed.

Further, when the length of the upper PC bracket 41B in the front-rear direction of the protruding portion 41c is shorter than that of the lower PC bracket 41A, the upper PC bracket 41B may be integrated without being vertically divided.

10... Existing building, 11... Existing pillar (pillar), 12... Upper foundation (upper structure), 13, 15... Base plate, 14... Foundation (lower structure), 16... Reinforced part, 17... Reinforcement plate, 18... Reinforcement plate, 19... First floor slab, 20... Seismic isolation device, 21, 22... Flange plate, 30... Jack, 31... Sliding plate, 41... PC bracket (bracket), 41A... Lower PC bracket, 41B... Upper part PC bracket, 41a... Abutting surface, 41b... Pressing part, 41c... Projection part, 41d... Sheath tube, 41e... Notch part, 41f... Coupling part, 41g... Sheath tube, 42... PC steel bar (tension bar material), 43... Nut, 44... Auxiliary PC steel rod (auxiliary tension rod material), 45... Auxiliary bracket, 45a... Sheath tube, 47... Auxiliary connecting plate (auxiliary connecting member).

Claims (7)

Seismic isolation that replaces the seismic isolation device that is located below the pillar of the existing building and is located between the upper structure made of concrete that is integral with the pillar and the lower structure that is separate from the upper structure Construction method,
A pair of concrete brackets sandwiching the pillar from both sides, a tension rod so as to pass through the protrusions located on both outer sides in the direction orthogonal to the sandwiching direction so as to pass through the outside in the direction orthogonal to the sandwiching direction of the pillar. Inserting each of the materials, connecting with the tension bar material under tension,
A step of forming a double-strike portion by re-stretching concrete on the upper structure,
Installing a jack between the additional striking portion and the lower structure;
Releasing the connection between the seismic isolation device and one of the lower structure or the upper structure,
Extending the jack,
Releasing the connection between the seismic isolation device and the other of the lower structure or the upper structure,
Replacing the seismic isolation device with a new seismic isolation device;
A step of shortening the jack,
Connecting the new seismic isolation device to the upper structure and the lower structure;
A step of removing the pair of brackets and the tension rod material,
Each of the brackets has a cutout portion that is recessed toward the column between a direction orthogonal to the sandwiching direction of the protrusion, and a connecting portion that connects the protrusions in a direction orthogonal to the sandwiching direction. A seismic isolation work method characterized by that. An upper structure that is located below the pillar of an existing building and is made of concrete integrally with the pillar, the upper structure, and the lower part separated from the upper structure by securing a portion for inserting the seismic isolation device in the pillar. A seismic isolation construction method that installs a seismic isolation device between the structure and
A pair of concrete brackets sandwiching the pillar from both sides, a tension rod so as to pass through the protrusions located on both outer sides in the direction orthogonal to the sandwiching direction so as to pass through the outside in the direction orthogonal to the sandwiching direction of the pillar. Inserting each of the materials, connecting with the tension bar material under tension,
A step of forming a double-strike portion by re-stretching concrete on the upper structure,
Installing a jack between the additional striking portion and the lower structure;
Extending the jack,
Inserting the seismic isolation device between the upper structure and the lower structure;
A step of shortening the jack,
Connecting the seismic isolation device to the upper structure and the lower structure;
A step of removing the pair of brackets and the tension rod material,
Each of the brackets has a cutout portion that is recessed toward the pillar in a direction orthogonal to the sandwiching direction of the protrusion, and a connecting portion that connects the protrusions in a direction orthogonal to the sandwiching direction. A seismic isolation work method characterized in that 3. The seismic isolation work method according to claim 1, further comprising a step of attaching a reinforcing plate so as to extend over a lower surface of the upper structure and a lower surface of the additional striking portion. Between the pair of brackets, a step of providing an auxiliary bracket made of concrete, which is located outside in a direction orthogonal to the sandwiching direction of the pillar, and through which the tension rod member is inserted, is provided. The seismic isolation work method according to any one of Items 1 to 3. The step of inserting an auxiliary tension rod member that connects the two protrusions in a direction orthogonal to the sandwiching direction to the two protrusions of each of the brackets, and applying a tension force to the two protrusions. The seismic isolation work method according to any one of 4 above. Each of the brackets is divided in the vertical direction, and the tension rod member is inserted into each of the divided brackets,
The seismic isolation work method according to any one of claims 1 to 5, wherein the length of the protrusion of the upper bracket is shorter than the length of the protrusion of the lower bracket. Base according to any one of claims 1 to 6, characterized in that attachment of the auxiliary connecting member for connecting the projecting portions in the direction perpendicular to the sandwiching direction, to the bracket by ligation by the tension bar Earthquake construction method.