JP6351355B2 - Seismic isolation method for existing buildings - Google Patents

Description

  The present invention relates to a seismic isolation method for an existing building for improving seismic performance by installing a seismic isolation device in a pillar of the existing building.

  In recent years, seismic isolation devices have been installed on specific floors for various existing buildings such as reinforced concrete (RC) structures that have not undergone seismic isolation measures in order to reduce the damage caused by large earthquakes. Therefore, measures are being taken to seismically isolate the entire building or part of it.

When such an existing building is subjected to seismic isolation, it is necessary to cut the column once since it is made by newly inserting a seismic isolation device into the column on the specific floor.
10 and 11 show this type of seismic isolation method proposed previously by the present applicant in the following Patent Documents 1 and 2 and the like.

  In this seismic isolation method, first, square pillar-shaped reinforced concrete 31 is placed on the upper and lower outer peripheries of the range where the seismic isolation device for the column 30 is to be interposed, and between the three upper and lower reinforced concrete 31 surfaces. In addition, a fixing plate 33 is disposed on the other surface, and a prestress is introduced between the support material 32 and between the support plate 32 and the fixing plate 33 through a PC steel rod 34, and then both ends. Is fixed with a nut, and the upper and lower ends of the support member 33 are increased and pressed against the cast concrete 31.

  As described above, after the axial force acting on the column 30 is increased and temporarily supported by the support material 32 via the cast concrete 31, the seismic isolation device for the column 30 should be inserted from the opening S side formed on the one surface. Cut the site. Next, the upper and lower mounting bases of the seismic isolation device are respectively constructed on the opposite surfaces of the cut pillars 30, and the seismic isolation device is inserted and installed between the upper and lower mounting bases from the opening S side. By pulling out 34 and removing the support member 32 and the fixing plate 33, the seismic isolation for the existing pillar 30 is completed.

JP 2001-49873 A JP 2000-257273 A

  By the way, in the conventional seismic isolation method of the existing building, the load of the pillar 30 is supported by the support member 32 on the three faces of the pillar 30, and the pillar 30 is cut from the opening S side formed on the other face. Work such as construction of upper and lower mounting bases and insertion of seismic isolation devices. For this reason, the work space is narrowed, and it is necessary to perform the cutting of the pillar 30 and the removal of the cut portion, and the installation of the mounting base and the seismic isolation device from the one surface side. There was a problem.

  Further, since the load is supported by the support members 32 temporarily provided on the three surfaces of the column 30 and the load is not supported on the other surface where the opening S is formed, the support balance is poor. When the load is large, the pillar 30 may be inclined. Therefore, if the number of support members 32 is increased to cope with this, the number of PC steel bars 34 for increasing the number of PC members 34 and press-contacting them to the concrete 31 increases, and the labor and cost required for the work increase. There was also a problem.

  Further, since the PC steel bar 34 is used to press-contact the support member 32 against the additional cast concrete 31, it is difficult to avoid a reinforcing bar in the increased cast concrete 31 and provide a PC steel bar 34. There is also a problem that construction work becomes large because jacks for applying tension to the arm are required.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a seismic isolation method for an existing building that is excellent in workability and can shorten the work period and reduce the cost. It is what.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a construction method for installing a seismic isolation device in a pillar of an existing building, and an upper and lower portion of the column in which the seismic isolation device is to be inserted In addition to constructing reinforcement and formwork for increasing the outer perimeter of the steel, axial force transition steel plates arranged across the upper and lower parts are provided on the two opposing surfaces of the column, and then concrete is placed in the formwork. The upper and lower portions of the axial force transition steel sheet should be fixed to the reinforcing portion by connecting means, and then the seismic isolation device for the column should be interposed. The axial force transition steel plate is removed after cutting the range and inserting the seismic isolation device into the cutting site.

  The invention according to claim 2 is the invention according to claim 1, wherein the axial force transition steel sheet constitutes at least a part of the formwork, and a convex is formed on the inner surface of the part. It is characterized by that.

According to the invention described in any one of claims 1 and 2 , since the axial force transition steel plates are provided on the two opposite surfaces of the pillar, the opening is formed on the two surfaces adjacent thereto. For this reason, cutting of a pillar, carrying out of a cutting part, carrying in and attachment work of a seismic isolation device can be performed from said 2 side in which the above-mentioned opening is formed, and it is excellent in workability.

  Moreover, since the load of the column is supported by the axial force transition steel plates fixed to the two opposing surfaces of the column, the load can be temporarily supported stably.

  In this case, in the invention described in claim 2, the upper and lower portions are respectively increased, and a convex portion is formed on the inner surface of the mold component part of the axial force transition steel plate that constitutes a part of the cast concrete mold. Therefore, it is possible to increase the integrity after placing the cast-in-place concrete and enhance the stability of the load support.

  As a result, without using an expensive PC steel bar or a large jack as in the prior art, it is possible to increase the axial force transition steel plate with a lightweight small torque wrench or the like and firmly fix it to the reinforced portion of the concrete. It is possible to greatly reduce the labor and cost in construction.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure for describing one Embodiment of this invention, (a) is a cross-sectional view which shows the state which installed the post-construction anchor in the upper and lower parts of a pillar, (b) is a front view. FIG. 2 shows a state in which predetermined bar arrangement is performed on the upper and lower parts of the column in FIG. FIGS. 3A and 3B show a state in which connecting means and a mold are installed on the upper and lower portions of the column in FIG. 2, and FIG. It is a cross-sectional view of an essential part showing a state after the additional cast concrete is placed. 4 shows the connecting means of FIG. 4, wherein (a) is an exploded view and (b) is an assembly view. FIG. It is a figure for demonstrating the effect | action of the connection means of FIG. The state which cuts and removes a part of pillar after supporting the load of a pillar on an axial force transfer steel plate is shown, (a) is a front view, (b) is a side view. It is a side view which shows the state which installed the seismic isolation apparatus in the cut part of the pillar of FIG. It is a front view which shows the completion state which removed the axial force transfer steel plate of FIG. It is a front view which shows the state which supported the load of the column temporarily in the conventional seismic isolation method. It is a cross-sectional view of the main part of FIG.

Hereinafter, based on FIGS. 1-9, one Embodiment of the seismic isolation method of the existing building which concerns on this invention is described.
As shown in FIG. 1, this seismic isolation method is a method for interposing a seismic isolation device on a column 1 having a square cross section in an existing building. First, the seismic isolation device of the column 1 indicated by a dotted line in the figure is used. In order to form a reinforcing portion by placing additional cast concrete on the upper and lower portions 1a and 1b leaving the range H to be inserted, a roughening treatment is performed on the outer peripheral surface, and a post-construction anchor 2 is installed.

  Next, after the axial main reinforcement 3a and the hoop reinforcement 3b for the reinforcing part are installed around the upper and lower parts 1a and 1b, as shown in FIG. An axial force transition steel plate 4 straddling H is disposed, and its upper and lower portions 4a, 4b are installed as a part of a concrete formwork to be placed on the upper and lower portions 1a, 1b of the pillar 1. Further, conventional molds 5a and 5b are installed on the other outer circumferences of the upper and lower parts 1a and 1b. Thereby, the opening part S which the pillar 1 exposes is formed in two surfaces where the axial force transfer steel plate 4 is not arrange | positioned.

  Here, the said axial force transfer steel plate 4 is manufactured by the striped steel plate, for example, and as shown in FIGS. 4-6, the convex part 13 is formed in the inner surface side. Further, a rib 4d for buckling reinforcement is joined to the outer surface over the entire length in the vertical direction. In the present embodiment, six ribs 14 are provided in parallel in the horizontal direction at substantially equal intervals.

  And when constructing the said formwork, as shown to Fig.3 (a) in the up-and-down part (henceforth formwork) 4a and 4b beforehand, as shown in FIG. The connection means (refer FIG. 4 and FIG. 5) for making it press-contact with the reinforcement part formed by is assembled.

  The connecting means is inserted into the mold frames 4a and 4b through washers 6a from a plurality of (vertical 2 × horizontal 5 in the figure) holes respectively formed in the upper and lower portions 4a and 4b of the axial force transition steel plate 4. A high-strength bolt (bolt member) 6, a cap nut 7 that is disposed in the mold frames 4 a and 4 b and is screwed into the high-strength bolt 6 from one end side, and is screwed into the other end portion of the cap nut 7. Provided with an anchor bolt (anchor member) 8 and a ring-shaped elastic body 9 joined to a flange 7 a formed on one end of the cap nut 7.

In order to prevent cracking of the reinforced concrete, which will be described later, spiral reinforcing bars 10a are arranged on the outer periphery of each cap nut 7, and reinforcing bars 10b with fixing plates at both ends are horizontally provided at the end of the cap nut 7. Arrange the bars.
After completion of the above-mentioned formwork and bar arrangement construction, as shown in FIG. 4, by placing an additional cast concrete 11 in the formwork 4a, 4b, 5a, 5b, curing it for a predetermined period, and hardening it. A reinforcing portion 12 integrated with the pillar 1 is formed.

  Thus, after extending the reinforcement part 12 in the upper-lower part 1a, 1b of the range H which should interpose the seismic isolation apparatus of the pillar 1, as shown in FIG. 6, the high strength volt | bolt 6 is tightened. Then, since the cap nut 7 is prevented from moving in the axial direction by the anchor bolt 8, a tensile force is applied to the high strength bolt 6 and the cap nut 7, and the elastic member 9 is compressed by the reaction force to shift the axial force. The upper and lower portions 4 a and 4 b of the steel plate 4 are pressed against the reinforcing portion 12.

  At this time, because the convex portion 13 is formed on the surface of the upper and lower portions 4a and 4b facing the reinforcing portion 12, a large frictional force is generated between the upper and lower portions 4a and 4b and the reinforcing portion 12, The axial force transition steel plate 4 is firmly fixed to the reinforcing portion 12.

  Then, as shown in FIG. 7, the column 1 in the range H is cut and removed from the two openings S sandwiching the column 1 therebetween. Thereby, the load of the pillar 1 is supported by the axial force transition steel plate 4. In this state, as shown in FIG. 8, the upper and lower mounting bases 15 and 16 of the seismic isolation device are respectively constructed on the opposite surfaces of the cut pillar 1, and the upper and lower mounting bases 15 and 16 are formed from the opening S side. The seismic isolation device 17 is inserted into and installed.

  Then, as shown in FIG. 9, the high-strength bolt 6 is removed, the axial force transition steel plate 4 is removed, and the upper and lower mounting bases 15 and 16 are subjected to a fireproofing process, thereby making the existing pillar 1 seismic isolation. Is completed.

  As described above, according to the seismic isolation method for an existing building having the above-described structure, the upper and lower portions 4a and 4b are respectively added to the two opposing surfaces of the pillar 1 and constitute a part of the formwork of the cast concrete 11. As a result of the provision of the axial force transition steel plate 4, openings S are formed on the two surfaces adjacent thereto. For this reason, as shown in FIG. 7 and FIG. 8, the cutting of the pillar 1 and the removal of the cut portion 18, the installation of the upper and lower mounting bases 15 and 16, and the installation and installation of the seismic isolation device 17 It can be performed from the opening S side, and is excellent in workability.

  Moreover, since the load of the pillar 1 is supported by the axial force transition steel plate 4 fixed to the two opposing surfaces, the support force can be temporarily supported without causing a bias, and the axial force transition can be performed. The convex part 13 can be formed in the contact surface with the reinforcement part 12 of the steel plate 4, and integrity can be improved and the stability of load support can be improved.

  Further, the upper and lower portions 4a and 4b of the axial force transition steel plate 4 are cap nuts 7 with anchor bolts 8 embedded in the reinforcing portion 12, and the high strength bolt 6 screwed from the axial force transition steel plate 4 to the bag nut 7 And the elastic member 9 disposed between the axial force transition steel plate 4 and the cap nut 7, and after forming the reinforcing portion 12, the high strength bolt 6 is tightened to press and fix the reinforcing portion 12. Therefore, the above-mentioned fixing can be performed with a light and small torque wrench etc. without using an expensive PC steel bar or a large jack as in the prior art, thereby greatly reducing the labor and cost in construction. Can do.

  In the above embodiment, the anchor bolt 8 screwed into the cap nut 7 is used as the anchor member integrated with the cap nut 7, but the present invention is limited to this. Instead of this, various forms such as closing the tip opening of the cap nut 7 and joining an anchor to the outer peripheral surface of the cap nut 7 can be adopted.

1 pillar 1a, 1b top and bottom of pillar 4 axial force transfer steel plate 4a, 4b top and bottom part (formwork)
6 High strength bolt 7 Cap nut 8 Anchor bolt (anchor member)
DESCRIPTION OF SYMBOLS 9 Elastic member 11 Reinforced concrete 12 Reinforcement part 13 Convex part 17 Seismic isolation device H Range which installs a seismic isolation device S Opening part

Claims (2)

A method for installing seismic isolation devices on pillars of existing buildings,
In addition to constructing reinforcement and formwork for increasing the outer circumference of the upper and lower parts of the column in the range where the seismic isolation device should be inserted, it is arranged on the two opposing surfaces of the column across the upper and lower parts After forming a reinforcing part on the upper and lower parts by placing concrete in the formwork, and then fixing the upper and lower parts of the axial force transferring steel sheet to the reinforcing part by connecting means Then, after cutting the range of the pillar to be installed with the seismic isolation device, inserting the seismic isolation device into the cut site, and then removing the axial force transition steel plate, Seismic construction method.   2. The seismic isolation method for an existing building according to claim 1, wherein the axial force transition steel sheet constitutes at least a part of the formwork, and a convex is formed on an inner surface of the part. 3. .