JP5316897B2 - Seismic isolation method - Google Patents

Description

  The present invention relates to a seismic isolation method, and more particularly to a seismic isolation method for a solid foundation existing building.

  Conventionally, seismic isolation methods for existing buildings by seismic isolation retrofit are known (see, for example, Patent Documents 1 and 2). In this existing building seismic isolation method, an existing building is seismically isolated by dividing the existing building into a lower structure and an upper structure and installing a seismic isolation device such as laminated rubber between them.

  11 and 12 are schematic process diagrams of the seismic isolation method of Patent Document 1. FIG. As shown in FIG. 11A, the existing building 1 has a solid foundation 2, a lowest floor slab 3, and a pillar 4. The ground supporting the solid foundation 2 is excavated from around the existing building 1 to secure the work space 5. Next, as shown in (b), a pile body 6 is constructed by a deep foundation method at a position directly below each column 4. Next, as shown in (c), a support 7 made of a steel frame or the like is interposed between the pile body 6 and the solid foundation 2, and a column load is temporarily supported by the pile body 6 via the support 7.

  Then, as shown to Fig.12 (a), the whole lower ground of the solid foundation 2 is further excavated, the seismic isolation pit 8 is provided, and the top part of the pile body 6 is exposed. Next, as shown in (b), a bottom plate 9 is newly installed in the seismic isolation pit 8, and the tops of the pile bodies 6 are integrated by the bottom plate 9. Next, as shown in (c), the seismic isolation device 10 is installed on the bottom base 9 and the support 7 is removed, and the existing building 1 is isolated from the bottom base 9 via the seismic isolation device 10 and completed. Become.

Japanese Patent No. 3787814 JP 2007-85021 A

  By the way, like the above-mentioned conventional patent document 1, in the seismic isolation retrofit of the existing building whose foundation is a solid foundation, a working space for excavating the solid foundation and installing the seismic isolation device is created. In this case, prior to the installation of the seismic isolation device, a plurality of temporary support members are provided in the work space to temporarily support the solid foundation. At this time, since the solid foundation is a work space, a large bending stress is generated on the solid foundation due to the weight of the existing building. In particular, the solid foundations of existing buildings that are older than 50 years may be lower in bending strength than solid foundations constructed in recent years, such as being composed of single reinforcement concrete. It is difficult to evaluate the bending strength as a structure against stress. This made seismic isolation work difficult for existing buildings on solid foundations and increased construction costs. For this reason, the development of a simple and inexpensive seismic isolation method for existing buildings on solid foundations has been desired.

  This invention is made | formed in view of the above, Comprising: It aims at providing the simple and cheap seismic isolation method for the existing building of a solid foundation.

  In order to solve the above-described problems and achieve the object, the seismic isolation method according to claim 1 of the present invention is a seismic isolation method for an existing building provided on a solid foundation, After increasing the thickness to improve the bending strength against the loading load, a work space is formed under the thick solid foundation, and a seismic isolation device is installed in this work space to support the solid foundation. It is characterized by.

  Moreover, the seismic isolation method according to claim 2 of the present invention is the above-described method according to claim 1, wherein a part of the solid foundation is removed to form a space for a beam, and this space and the solid foundation upper surface are formed. After increasing the thickness of the solid foundation by increasing the thickness of the hardened material, a work space is formed by excavating the ground below the thick solid foundation, and a temporary support material is provided on the ground of the work space. Temporarily supporting the solid foundation, providing a new foundation, installing a seismic isolation device between the new foundation and the solid foundation, and removing the temporary support material.

  The seismic isolation method according to claim 3 of the present invention is characterized in that in claim 2 described above, the solid foundation is removed in a strip shape in plan view to form a space for a beam.

  The seismic isolation method according to claim 4 of the present invention is characterized in that, in claim 2 or 3 described above, reinforcing bars are arranged in the space for the beam.

  According to the present invention, there is provided a seismic isolation method for an existing building provided on a solid foundation, and after increasing the thickness of the solid foundation to improve the bending strength against the loading load, A work space is formed underneath, and a seismic isolation device is installed in this work space to support the above-mentioned solid foundation in isolation, so that the bending strength of the solid foundation is improved, and this solid foundation is temporarily supported to install the seismic isolation device. Workability at the time of installation is improved. For this reason, it has the effect that the seismic isolation work of the existing building which is a solid foundation can be implemented simply and inexpensively.

FIG. 1 is a schematic flowchart showing an embodiment of the seismic isolation method according to the present invention. FIG. 2 is a side cross-sectional view showing a process of the seismic isolation method according to the present invention, and is a view showing a state in which a part of the solid foundation is removed. FIG. 3 is a view showing a state in which beam reinforcing bars are constructed. FIG. 4 is a view showing a state where the thickness of the solid foundation is increased. FIG. 5 is a diagram showing a state in which the work space under the solid foundation is temporarily supported by the temporary support material. FIG. 6 is a view showing a state in which the solid foundation is temporarily supported by a temporary support material. FIG. 7 is a view showing a state in which a bottom plate is newly provided on the ground of the work space. FIG. 8 is a view showing a state where the seismic isolation device is installed. FIG. 9 is a plan sectional view of the solid foundation of FIG. FIG. 10 is an enlarged view of the solid foundation of FIG. FIG. 11 is a schematic process diagram (first half) of a conventional seismic isolation method. FIG. 12 is a schematic process diagram (second half) of a conventional seismic isolation method.

  Below, the Example of the seismic isolation method concerning this invention is described in detail based on drawing. Note that the present invention is not limited to the embodiments.

  As shown in FIGS. 1 and 10, the seismic isolation method according to the present invention is a seismic isolation method for an existing building 1 provided on a solid foundation 12, and the existing foundation 1 is increased in thickness. After improving the bending proof strength with respect to the weight of 1 (uploading load), a work space 24 is formed under the thickened solid foundation 12, and the seismic isolation device supports the solid foundation 12 in a seismic isolation manner in the work space 24. Is to be installed.

A specific construction procedure will be described with reference to FIGS.
First, prior to full-scale construction, reduce the ground contact pressure of the solid foundation. Specifically, the load on the solid foundation and the finishing load are removed to reduce the load as much as possible.

  As shown in the plan sectional views of FIGS. 2 and 9, the solid foundation 12 of the existing building 1 is cut and removed in a strip shape in plan view to form a space 14 for beams. The position to be cut and removed is a position avoiding the pillar 11 of the existing building 1. The strip-shaped cutting width B is preferably determined by the contact pressure of the solid foundation 12.

  Subsequently, as shown in FIG. 3, a beam reinforcement 16 (rebar) is constructed in a beam space 14 formed by cutting. The beam reinforcement 16 is integrated with the solid foundation 12 and an anchor (not shown). In addition, it is preferable to determine the specification of the beam reinforcement 16 in consideration of the jackup stress generated in the subsequent process in addition to the load acting after completion. Further, the slab reinforcement 28 is arranged on the upper surface side of the solid foundation 12.

  Next, as shown in FIG. 4, a reinforced concrete 18 (hardening material) is added as much as possible over the space 14 for the beam and the upper surface of the solid foundation 12, and a beam 20 is newly installed in the space 14 for the beam. Integrate with the existing solid foundation 12. In this way, the thickness of the solid foundation 12 as a whole is increased to improve the bending strength against the weight of the existing building 1.

  Next, as shown in FIGS. 5 and 10, the ground 22 below the thick foundation 12 is excavated from the periphery of the existing building 1 to form a work space 24 under the solid foundation 12. The size of the work space 24 is ensured to be large enough to carry out the installation work of the seismic isolation device 34 in the subsequent process.

  Next, as shown in FIG. 6, while digging up the working space 24, a temporary support member 30 is interposed between the ground 22 and the solid foundation beam 20, and the beam load is temporarily supported by the temporary support member 30. . In this case, the temporary support material 30 is provided by press-fitting a steel pipe pile into the ground 22 with a jack by, for example, an underpinning method. When the temporary support member 30 is installed, a beam load is temporarily received by the jack, the jack is removed, and the beam load is stored in the temporary support member 30.

  Next, as shown in FIG. 7, the entire lower ground of the solid foundation 12 is further excavated, and a bottom board 32 (new foundation) is newly installed on the ground 26 of the work space 24. The bottom 32 is supported by the ground while supporting the entire existing building 1 via the seismic isolation device 34 (see FIG. 8). It shall be of the structure provided.

  Finally, as shown in FIG. 8, a seismic isolation device 34 such as laminated rubber is installed between the newly installed bottom base 32 and the solid foundation beam 20, and the temporary support member 30 is removed. The entire existing building 1 is isolated from the bottom plate 32 through the base. In this way, the seismic isolation construction of the existing solid foundation building 1 is completed.

  By doing in this way, the bending strength of the solid foundation 12 is improved, and workability at the time of installing the seismic isolation device 34 by temporarily supporting the solid foundation 12 is enhanced. For this reason, it is possible to easily and inexpensively carry out seismic isolation work for existing buildings that have a solid foundation.

  In particular, since a solid foundation with an old age may have low bending strength, it is difficult to apply a conventional seismic isolation retrofit construction that forms a work space under the solid foundation as it is. However, according to the present invention, even in an existing building with a solid foundation that is older in age, the bending space of the solid foundation 12 is improved by increasing the thickness, and it is difficult to cause bending fracture, and the work space 24 is formed below this. Therefore, the workability is improved and the seismic isolation retrofit can be easily performed.

  Further, depending on the design of the newly installed beam 20 in the solid foundation 12, it is possible to increase the arrangement interval of the temporary support members 30. If the arrangement interval can be widened, the amount of the temporary support member 30 used can be reduced, and the temporary cost can be reduced.

  As described above, according to the present invention, there is a seismic isolation method for an existing building provided on a solid foundation, and after increasing the thickness of the solid foundation to improve the bending strength against an overload, A work space is formed under the thickened solid foundation, and a seismic isolation device is installed in this work space to provide seismic isolation support for the solid foundation, thus improving the bending strength of the solid foundation and temporarily supporting the solid foundation. This improves the workability when installing the seismic isolation device. For this reason, it is possible to easily and inexpensively carry out seismic isolation work for existing buildings that have a solid foundation.

  As described above, the seismic isolation method according to the present invention is useful for seismic isolation of an existing building which is a foundation with a solid foundation, and in particular, the seismic isolation work for an existing building with a solid foundation whose age is old. Suitable for simple and inexpensive implementation.

1 Existing building 12 Solid foundation 14 Space for beam 16 Beam reinforcement (rebar)
18 Concrete (hardening material)
20 Beams 22, 26 Ground 24 Work space 28 Slab reinforcement 30 Temporary support material 32 Bottom base (new foundation)
34 Seismic isolation device

Claims (4)

A seismic isolation method for existing buildings on solid foundations,
After the thickness of the solid foundation is increased to improve the bending strength against the loading load, a work space is formed under the thickened solid foundation, and the seismic isolation device supports the solid foundation in a seismic isolation manner in this work space. Seismic isolation method characterized by installing   A portion of the solid foundation is removed to form a space for the beam, and after thickening the solid foundation by striking a hardener over the space and the solid foundation upper surface, the thickened solid Excavation of the ground below the foundation to form a work space, a temporary support material is provided on the ground of this work space to temporarily support the solid foundation, a new foundation is provided, and the space between the new foundation and the solid foundation The seismic isolation method according to claim 1, wherein a seismic isolation device is installed to remove the temporary support material.   The seismic isolation method according to claim 2, wherein the solid foundation is removed in a strip shape in plan view to form a space for a beam.   The seismic isolation method according to claim 2 or 3, wherein reinforcing bars are arranged in the space for the beam.

Images