JP4289271B2 - Seismic retrofit method for existing buildings - Google Patents

Description

  The present invention relates to a seismic retrofit method and a seismic retrofit structure for an existing building that improves seismic performance of the building by adding a seismic control device to the existing building.

In recent years, in various existing buildings, in order to ensure safety in the event of an earthquake, braces have been added diagonally, V-shaped, inverted V-shaped, etc. to a frame constructed of columns and beams. Seismic reinforcement is performed to increase the rigidity of the frame.
However, the seismic reinforcement for the existing building has the disadvantage that the weight of the building itself increases, although the earthquake resistance of the frame can be increased by the axial strength of the braces. In addition, since it does not have a damping effect on the vibration generated in the building during an earthquake or the like, a seismic control effect cannot be expected.

  Therefore, in the past, when performing seismic retrofitting using seismic control effects, seismic control such as oil dampers, viscous dampers, viscoelastic dampers or elasto-plastic dampers using extremely low yield point steel for the existing building frame. The structure which tries to suppress the response vibration which acts on the existing building by providing the brace and wall which incorporated the member is employ | adopted.

  However, in the seismic retrofitting method and the seismic retrofitting structure constructed by adding braces that incorporate seismic control members into existing buildings, the seismic control effect of the seismic control members is not limited to existing buildings during an earthquake. Since it depends on the amount of relative displacement that occurs in the frame, there is a problem that a desired seismic control effect cannot be obtained when the frame itself and other deformability of the existing building are small.

Based on such problems, there has been proposed a seismic repair method for existing buildings as seen in Patent Document 1 below.
In this seismic retrofit method, first, a slit extending in the vertical direction is formed in the seismic wall of an existing building, so that the seismic wall is divided into a plurality of horizontally adjacent walls, and both wall surfaces of these walls are separated. The damper constituent material made of ultra-soft steel is disposed so as to straddle between both wall bodies, and then the damper constituent members located on both wall surfaces of the wall body are coupled to each other by bolts and nuts penetrating the wall body. The wall bodies are connected to each other by being integrated with the body.

According to the seismic retrofit method having the above configuration, the seismic wall is divided by forming a vertical slit, so that the deformation performance of the wall can be improved, and the seismic energy by the damper constituent material made of ultra mild steel There is an advantage that can be absorbed.
Japanese Patent Laid-Open No. 11-62268

  However, when an earthquake occurs, large inter-layer displacement occurs in the horizontal direction in the building, whereas in the conventional seismic retrofit method described above, the column is still constrained by the wall as a result of forming slits in the vertical direction. Therefore, the deformation performance cannot be improved. For this reason, there exists a problem that the deformation | transformation performance as the whole frame cannot fully be improved.

  In addition, a plate-like member made of ultra-soft steel is used as the damper component, and since this is bridged between both wall bodies, there is a limit to the amount of elastic-plastic deformation by the damper structure, and the damper structure The horizontal force acts as an axial force. For this reason, with respect to a large amount of displacement in the horizontal direction, the energy absorption effect cannot be exhibited following this, and there is a limit to the expected vibration control effect. In addition, there is a drawback that it does not function for horizontal displacement in the out-of-plane direction.

The present invention has been made in view of such circumstances, and can exhibit a high seismic control effect by the added seismic control device even for a large-scale earthquake, thereby obtaining an excellent effect of improving seismic performance. It is an object to provide a method for seismic retrofit of existing buildings.

In order to solve the above-mentioned problems, the invention described in claim 1 is characterized in that a horizontal slit is formed by cutting a wall provided so as to form a frame in a frame composed of columns and beams of an existing building. Te, divides the wall up and down, then the space in the slit, and the plate-shaped member fixed above the wall, a plate member fixed to the lower of the wall, between the plate-like member A vibration control device in which a viscoelastic body interposed between the two is disposed in a stacked manner is attached.

According to the second aspect of the present invention, by cutting a wall provided so as to form a frame in a frame composed of columns and beams of an existing building, a horizontal direction is provided between the walls and the beams. A slit is formed, and then a plate-like member fixed to the upper beam or wall, a plate-like member fixed to the lower wall or beam, and a space between the plate-like members are formed in the space in the slit. A vibration control device in which the interposed viscoelastic body is disposed in a laminated form is attached.

According to the seismic retrofit method for an existing building according to claim 1 or 2, a horizontal slit is formed between the wall or the wall and the beam constituting the frame of the existing building to divide it vertically. Therefore, the deformation performance of the column during an earthquake or the like is enhanced, and as a result, the amount of horizontal displacement of the frame can be increased, and an increase in the weight of the frame due to this can be suppressed to a small extent.

  In addition to installing a viscoelastic damper capable of exhibiting effective vibration control performance against a large relative displacement as a vibration control device in the slit, the length dimension of the viscoelastic damper is approximately columnar. Since it is possible to set the inner span for a long time, it is possible to obtain an extremely high seismic performance improvement effect.

  Here, if the vibration control device is installed so that it is a space in the slit and fits in the plane of the wall, there will be no projecting from both sides of the wall after refurbishment, and therefore limited to indoor use Is more preferable because it does not occur. In addition, when the vertical dimension of the slit is small, it is preferable to form the slit so as to reach the columns on both sides so as to obtain the desired column deformation performance.

(Embodiment 1)
FIG. 1, FIG. 2 and FIG. 5 show a first embodiment of the existing building damping control method and the damping control structure obtained thereby.
In this seismic retrofitting method, first, as shown in FIG. 5, a wall 3 provided so as to constitute a part of a frame in a frame composed of columns 1 and beams 2 of an existing building is indicated by a dotted line in the figure. Cut as shown. Thereby, the wall 3 is divided into an upper wall body 3a and a lower wall body 3b, and a horizontal slit 4 reaching the pillars 1 on both sides is formed between the upper and lower wall bodies 3a and 3b.

Next, a plurality of anchors 9a are embedded in the lower surface of the upper wall 3a and the upper surface of the lower wall 3b so as to protrude from the lower surface or the upper surface, respectively.
A viscoelastic damper (damping device) 5 is installed in the slit 4. This viscoelastic damper is composed of four plate-like members 6a to 6b arranged in a stacked manner in the vertical direction with the plate surface horizontal, and a viscoelastic body 7 provided between these plate-like members 6a to 6d. It is constructed, and is formed so that its width dimension is within the plane of the wall 3 in the slit 4.

  Here, the uppermost plate-like member 6a is formed to have a width dimension equal to the thickness dimension of the wall 3, and a web of a U-shaped shaped steel 8 is joined to the upper surface thereof. On the other hand, the lowermost plate-like member 6d is also formed with a width dimension equal to the thickness dimension of the wall 3, and a web of a U-shaped shaped steel 8 is joined to the lower surface thereof. A large number of anchors 9b are erected on these webs.

  The plate member 6c at the third level from the top is integrated with the uppermost plate member 6a at one end in a U shape, and the plate member 6b at the second level is integrated at the other end. The lower plate-like member 6d is integrated in a U shape. And the viscoelastic body 7 provided between these plate-shaped members 6a-6d is stuck to the plate-shaped members 6a-6b which the both surfaces oppose.

  In order to install the viscoelastic damper 5 having the above-described configuration in the slit 4, the upper and lower structural steels 8 are placed along the upper wall body 3a and the lower wall body 3b with the anchor 9a positioned therein. Each grout 10 is poured into the steel 8 and solidified. As a result, the plate members 6a and 6c are integrally fixed to the upper wall body 3a side, and the plate members 6b and 6d are integrally fixed to the lower wall body 3b side. By installing the viscoelastic damper 5 in the slit 4 in this manner, the above-described seismic retrofit method is completed.

(Embodiment 2)
3 to 5 show a second embodiment of the existing building damping control method and the damping control structure obtained by the method according to the present invention. In this damping control method, first, FIG. As shown in the figure, a wall 11 provided to constitute a part of a frame in a frame composed of columns 1 and beams 2 of an existing building is shown in FIG. Cut with a larger vertical dimension than in the case of.

Thus, the wall 11 is divided into an upper wall body 11a and a lower wall body 11b, and a horizontal slit 12 reaching the pillars 1 on both sides is formed between the upper and lower wall bodies 11a and 11b.
Next, a plurality of anchors 19a are embedded in the lower surface of the upper wall body 11a and the upper surface of the lower wall body 11b so as to protrude from the lower surface or the upper surface, respectively. A viscoelastic damper (damping device) 13 is installed in the slit 12.

  This viscoelastic damper 13 is laminated in the horizontal direction by inserting three lower plate-like members 14 arranged in parallel with the plate surface vertical, and a gap between these lower plate-like members 14. The two upper plate-like members 15 disposed on the upper and lower plate-like members 14 and 15 and the viscoelastic body 16 provided between the upper and lower plate-like members 14 and 15 are schematically configured. Here, the viscoelastic body 16 provided between the upper and lower plate-like members 14 and 15 is attached to the upper and lower plate-like members 14 and 15 that are opposite to each other.

  The lower plate member 14 is erected integrally on the lower mounting plate 17. The lower mounting plate 17 is a flat plate having a width dimension substantially equal to the thickness dimension of the wall 11, and a U-shaped shaped steel 20 web is joined to the lower surface thereof. On the other hand, the upper end portion of the upper plate member 15 is joined to the upper mounting plate 18. Similarly, the upper mounting plate 18 is a flat plate having a width dimension substantially equal to the thickness dimension of the wall 11, and a U-shaped shaped steel 20 web is joined to the upper surface thereof. A large number of anchors 19b are erected on the web of the shape steel 20 respectively.

In order to install such a viscoelastic damper 13 in the slit 12, as in the first embodiment, the upper and lower shapes 20 are positioned inside the upper wall 11a and the lower wall 11b with the anchor 19a positioned therein. The grout 21 is poured into the shape steel 20 and solidified. Thereby, the upper plate-shaped member 15 is integrally fixed to the upper wall body 11a, and the lower plate-shaped member 14 is fixed to the lower wall body 11b integrally.
Note that reference numeral 22 in the figure is a spacer for maintaining a gap between the lower plate-like members 14, and reference numeral 23 in the figure is a spacer for holding a gap between the upper plate-like members 15.

  Further, in this seismic retrofitting method, the viscoelastic damper 13 having the above-described configuration is installed in the slit 12, and the notches that reduce the cross-section of the portion are respectively provided on the upper and lower portions of the pillars 1 on both sides facing the slit 12. By forming the portion 24, the seismic retrofit method is completed.

  As a result of cutting the wall 11, if the toughness at the portion 1a facing the slit 12 of the column 1 is insufficient, a resin such as steel tube winding reinforcement, carbon, aramid, or the like is further wound in the range indicated by the dotted line in the figure. Lateral reinforcement 25 such as the reinforcement hardened in step 1 is applied. Further, at least one of the lower plate member 14 or the upper plate member 15 may be provided on the lower mounting plate 17 or the upper mounting plate 18 so as to be swingable in the out-of-plane direction via a hinge or the like.

  According to the seismic retrofit method for an existing building and the seismic retrofit structure obtained thereby according to the first and second embodiments, the walls 3 and 11 constituting the frame of the existing building are attached to the pillars 1 on both sides. Since the horizontal slits 4 and 12 to reach are formed and divided into the upper wall bodies 3a and 11a and the lower wall bodies 3b and 11b, the deformation performance of the pillar 1 at the time of earthquake can be improved. As a result, the pillar 1 And the amount of horizontal displacement of the frame composed of the beams 2 increases.

  And when a big horizontal relative displacement arises between the beams 2 at the time of an earthquake, this is the viscoelastic body 7 between the plate-like members 6a and 6c and the plate-like members 6b and 6d, or between the plate-like members 14 and 15. While being transmitted to the viscoelastic body 16 as a shearing force and deformed, the vibration acting on the frame is attenuated by the viscous resistance force proportional to the speed exerted by the viscoelastic bodies 7 and 16 at the time of deformation.

At this time, the viscoelastic dampers 5 and 13 that can have effective vibration control performance even for a large horizontal displacement amount are provided in the slits 4 and 12 almost over the entire length between the columns 1. In addition, an extremely high seismic performance improvement effect can be obtained.
Moreover, since the viscoelastic dampers 5 and 13 are mounted so as to be within the slits 4 and 12 and within the surfaces of the walls 3 and 11, there is no projecting from both surfaces of the walls 3 and 11 after the repair. Therefore, there is no restriction on the use in the room.

  Further, if at least one of the lower plate member 14 or the upper plate member 15 is provided on the lower mounting plate 17 or the upper mounting plate 18 so as to be swingable in the out-of-plane direction via a hinge or the like, the horizontal in the out-of-plane direction. Even when a force is applied, it is possible to ensure a smooth relative displacement between the plate-like members 14 and 15.

Furthermore, in the first embodiment, the plate-like members 6a to 6d of the viscoelastic damper 5 are mounted with the plate surfaces arranged horizontally, which is effective against horizontal vibrations generated in the event of an earthquake. It can even show the seismic control performance.
On the other hand, in the second embodiment, the upper and lower plate-like members 14 and 15 of the viscoelastic damper 13 are mounted with their respective plate surfaces arranged vertically, so that the vertical width dimension of the slit 12 is set large. By doing so, a large vibration damping effect can be exhibited.

  Furthermore, in 2nd Embodiment, since the notch part 24 which reduces the cross section of the said part is formed in the upper and lower parts of the pillar 1 which faces the slit 12, respectively, the deformation | transformation performance of the pillar 1 at the time of an earthquake is raised more. The vibration damping effect by the viscoelastic damper 13 can be further improved.

  At this time, as a result of the large vertical dimension of the slit 12, the deformation performance of the column 1 is improved, but conversely, the yield strength at the time of an earthquake is reduced, and there is a risk of causing plastic fracture at an early stage. By implementing the lateral reinforcement 25 for increasing the toughness of the portion 1a, it is possible to improve the elastic strength of the column 1 and suppress the plastic fracture.

  In the first and second embodiments, only the case where the slits 4 and 12 are formed by cutting the walls 3 and 11 has been described. However, the present invention is not limited thereto, and Even if the slit is formed between the walls 3 and 11 and the upper or lower beam 2 and the viscoelastic dampers 5 and 13 are attached in the slit, the same effect can be obtained.

It is a front view which shows the state after damping control improvement in 1st Embodiment of this invention. It is a longitudinal cross-sectional view of FIG. It is a front view which shows the state after damping improvement in 2nd Embodiment of this invention. It is a longitudinal cross-sectional view of FIG. It is a front view which shows the position which cut | disconnects a wall in 1st and 2nd embodiment.

Explanation of symbols

1 Column 2 Beam 3, 11 Wall 3a, 11a Upper wall body 3b, 11b Lower wall body 4, 12 Slit 5, 13 Viscoelastic damper (damping device)
6a to 6d, 14, 15 Plate-like member 7, 16 Viscoelastic body 24 Notch 25 Lateral reinforcement

Claims (2)

Forming a horizontal slit by cutting the posts and consists of the beam rack premises wall provided so as to form a precursor of an existing building, it divides the wall up and down, then the space in the slit In addition, a plate-like member fixed to the upper wall, a plate-like member fixed to the lower wall, and a viscoelastic body interposed between the plate-like members are arranged in a stacked manner. Seismic retrofit method for existing buildings, characterized by installing seismic control devices. A horizontal slit is formed between the wall and the beam by cutting a wall provided to form a frame in a frame composed of columns and beams of an existing building. In a space, a plate-like member fixed to the upper beam or wall, a plate-like member fixed to the lower wall or beam, and a viscoelastic body interposed between the plate members are laminated. A seismic retrofitting method for an existing building, characterized by installing a seismic control device installed in the building.

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