JP6534026B2 - Seismic isolation building and its construction method - Google Patents

Description

  The present invention relates to a seismic isolation building and its construction method.

Conventionally, as a base isolation building, there is known a base isolation structure provided with a base isolation layer in which a base isolation device is interposed in a basement floor (see, for example, Patent Document 1).
In Patent Document 1, the foundation of a building existing at the bottom of a basement floor is a seismic isolation method for an existing building having steps in the height direction, and a foundation in which a base isolation system is interposed in the basement floor at each height. It describes about the seismic isolation building of the existing building which provided the seismic isolation layer.

JP 2002-121904 A

  However, in the above-described conventional base isolation structure, it is general to have a foundation beam shape, and in order to provide a base isolation layer further underground, it is necessary to dig the ground deeply throughout the foundation of the building at the time of construction. As a result, there is a problem that the cost increases, the construction period becomes long, and the construction quality decreases.

  The present invention has been made in view of the above-mentioned problems, and it is possible to reduce the number of underground excavations, to reduce the cost and construction period for construction, and to provide a seismically isolated building capable of securing construction quality. The purpose is to provide the construction method.

In order to achieve the above object, in the seismic isolation building according to the present invention, the core base portion supporting the core portion of the building is more basic than the outer portion supporting the core outer peripheral portion of the building forming the outer peripheral portion of the core portion. A base isolation structure having a deep bottom, wherein a foundation pile is installed on the core foundation portion and the outer periphery foundation portion, a retaining wall provided as a earth retaining portion of the core foundation portion, and the outer periphery foundation It is provided in temporary concrete between soils connected to the upper end of the retaining wall and embedded in the connecting rebar and installed in the outer peripheral foundation, while functioning as a main installation by being embedded in a mat slab cast in a part a temporary beam reinforcing bars are embedded in the temporary earthen concrete and integrally through the connecting reinforcement, provided basic bottom of the core foundation, by being embedded in the mat slab is Da設in the core base part With a temporary steel columns that function as set, and the core isolator provided on the mat slab of the core base portion, and an intermediate isolator provided on the ground floor of steel of the core outer peripheral portion, the beam rebar And the connection reinforcing bars are arranged so as to surround a pile head of the foundation pile which is placed between the temporary beam and the retaining wall in the outer peripheral foundation portion .

Further, in the method of constructing a seismically isolated building according to the present invention, the core base portion supporting the core portion of the building has a base bottom more than the outer peripheral portion supporting the core outer peripheral portion of the building forming the outer peripheral portion of the core portion. It is a construction method of the base isolation structure of the structure which becomes deep, and the process of providing a retaining wall as the earth retaining portion of the core foundation portion and embedding the connecting rebar by placing concrete and placing it in the outer periphery foundation portion And a process of providing temporary concrete between soils which functions as a permanent structure by being buried in a mat slab, and temporary reinforcement by embedding the rebar beam integrally with the temporary concrete between soils by placing the concrete in the outer peripheral foundation portion. a step of providing the beam, a step of connecting a portion of the temporary earthen concrete to the upper end of the earth retaining wall, a temporary steel columns underlying a bottom of the core base portion is provided, the temporary steel columns before A step function as the set by embedding the mat slab is Da設the core base portion, a step of providing a core isolator on the mat slab of the core base portion, the ground floor of steel of the core outer peripheral portion Providing an intermediate seismic isolation device at the same time.

In the present invention, by connecting the temporary soil concrete installed in the bottom of the outer foundation to the upper end of the retaining wall provided in the core foundation, the temporary soil concrete functions as a back anchor for the retaining wall, and the retaining wall Can be supported by pulling in the opposite direction to the direction in which it falls, so that the retaining wall can be prevented from falling. Therefore, a cutting beam generally required to be provided on the retaining wall of the core foundation can be omitted, and the cost can be reduced.
And since earthwork and frame work of the core part can be constructed without receiving the influence of the cutting beam, the work of cutting and laying the cutting beam in the core foundation part becomes unnecessary, and the construction period can be shortened. it can. In addition, since the cutting beam can be omitted, the reinforcing bar of the seismic isolation base portion and the formwork can be applied in advance in the foundation bottom of the excavated core foundation portion.

  In addition, by placing a temporary steel frame column directly above the pile at the bottom of the core foundation, work to build a permanent steel column on the temporary steel column at the stage before putting concrete in the mat slab on the core foundation. You can start early. That is, since the earth work accompanying the concrete placing of the mat slab in the core foundation portion and the construction work of the steel frame on the temporary steel frame column can be simultaneously performed, the process can be shortened.

In addition, since a mat slab is cast on the outer periphery foundation portion and an intermediate seismic isolation device is provided on the steel frame of the ground floor of the core outer periphery portion, foundation beams and isolation are directly installed on the foundation excavated bottom of the outer periphery foundation portion. There is no need to provide a seismic device, the depth of the bottom of the foundation can be kept small, and the amount of soil excavated and the number of frames can be reduced.
And since the position of the foundation bottom of a perimeter foundation part becomes a shallow position, it becomes possible to change a foundation excavated bottom to the height more than a usual water surface. In that case, drainage of ground water becomes unnecessary, and there is no need to provide drainage equipment, and work can be performed on the upper side of the surface of ordinary water, and other construction can be performed in the absence of groundwater. Has the advantage of improving

  Further, in the seismic isolation building according to the present invention, it is preferable that the seismic isolation foundation of the core seismic isolation device is formed of precast concrete.

In this case, the installation time of the seismic isolation foundation of the core seismic isolation device can be shortened after the placement of the mat slab in the core foundation portion.
In addition, since the seismic isolation foundation is made of precast concrete, the construction accuracy can be improved as compared with the case of construction on site.

  Moreover, in the construction method of the seismic isolation building which concerns on this invention, it is preferable that the earth retaining part of the said outer periphery base part is constructed by ground improvement.

  In this case, it is possible to improve the ground surface of the outer peripheral foundation portion at the time of excavation and make it function as a soil formwork, so it is possible to omit pile retaining (parent pile lateral arrow plate) and cutting beams. The reduction can be achieved.

  According to the seismic isolation building of the present invention and the construction method thereof, the number of underground excavations can be reduced, and the cost and time required for construction can be reduced, by adopting a structure in which the seismic isolation base portion in the underground is reduced. , The construction quality can be secured.

It is a side view which shows the construction state of the seismic isolation building by embodiment of this invention. It is a side view which shows the construction state of temporary concrete between soils. It is a top view which shows the structure of the rebar embed | buried under temporary soil concrete. It is a side view which shows the installation state of temporary steel frame columns. It is a side view which shows the construction procedure of a seismic isolation building. It is a side view which shows the construction procedure of the base-isolated building following FIG. It is a side view which shows the construction procedure of the base-isolated building following FIG. It is a side view which shows the construction procedure of the base-isolated building following FIG. It is a side view which shows the construction procedure of the base-isolated building following FIG. It is a side view which shows the construction procedure of the base-isolated building following FIG.

  Hereinafter, a seismic isolation building and its construction method according to an embodiment of the present invention will be described based on the drawings.

  As shown in FIG. 1, the seismic isolation building 1 according to the present embodiment is a multi-story building, and has a core portion 1A in the central portion in a plan view, and a basement floor of the core portion 1A. The seismic isolation layer M2 is provided, and the intermediate seismic isolation layer M2 is provided on the ground floor portion of the core outer peripheral portion 1B excluding the core portion 1A.

In this seismic isolation building 1, the core foundation portion 2A supporting the core portion 1A and provided with the foundation seismic isolation layer M1 is dug down to a position where the foundation bottom is deeper than the peripheral foundation portion 2B of the portion supporting the core outer peripheral portion 1B. Structure. On the foundation bottom of each of the foundations 2A and 2B, a mat slab 3 constructed by placing concrete over the entire surface is provided, and the steel frame 4 of the seismic isolation building 1 (core section steel 4A via the mat slab 3) , Outer peripheral steel frame 4B) is built. A plurality of foundation piles 2, 2,... Are placed at appropriate positions on each of the foundation portions 2A, 2B.
Here, among the mat slabs 3, those to be applied to the core base portion 2A are indicated by reference numeral 3A, and those to be applied to the outer peripheral base portion 2B are indicated by reference numeral 3B.

The base seismic isolation layer M1 has a configuration in which the core seismic isolation device 7A is provided directly on the mat slab 3A installed on the core foundation portion 2A.
The intermediate seismic isolation layer M2 is configured such that the intermediate seismic isolation device 7B is provided on the steel frame beam 42 provided in the lowermost layer of the ground floor of the outer peripheral steel frame 4B built in the outer circumferential base portion 2B.

  In addition, the seismic isolation building 1 is a temporary foundation soil concrete 5 (see FIG. 2) that functions as a main facility by being buried in a mat slab 3B that is placed in the foundation bottom of the outer periphery foundation portion 2B, and the core foundation portion 2A. And a temporary steel frame column 6 which is provided at the bottom of the foundation and is embedded in a mat slab 3A which is installed in the core foundation portion 2A and which functions as a main facility.

  As shown in FIG. 2, in the outer peripheral base portion 2B, the lower portion 2Ba is formed in a partial range near the core base portion 2A. The lower portion 2Ba is set to be slightly lower than the base bottom of the outer peripheral base portion 2B. Although the depth from the foundation bottom of perimeter peripheral part 2B of board down part 2Ba is set up arbitrarily, it is decided according to the placement thickness of temporary concrete soil 5 mentioned above.

  The temporary earth-to-earth concrete 5 is placed in the lower part 2Ba of the outer peripheral foundation 2B, and connected so as to bury the upper end 21a of the retaining wall 21 of the core foundation 2A on which the core 1A is provided. The temporary soil concrete 5 functions as a back anchor of the retaining wall 21 by the temporary beam 5A in which the beam reinforcement 5a is embedded and the temporary soil concrete 5, as shown in FIGS. 2 and 3, and the internal reinforcements 5a and 5b The fall force of the retaining wall 21 is prevented by extending the force with which the retaining wall 21 tends to fall to the outside (the core base portion 2A side) by applying a tensile force to the beam reinforcing bar 5a via the connecting rebar 5b. It has an action.

The temporary steel frame column 6 provided in the core foundation portion 2A supports the steel frame column 41 closest to the core portion 1A of the core outer peripheral portion 1B of the seismic isolation building 1, as shown in FIGS. As described above, by being embedded and integrally provided in the mat slab 3A to be installed in the core foundation portion 2A, it becomes a part of the permanent installation of the seismic isolation building 1.
As temporary steel frame column 6, H steel material thinner than permanent steel frame column 41 is used, and the length dimension is set so as to be longer than the thickness dimension of mat slab 3A cast in core foundation part 2A. It is done.

Here, the concrete construction method of the seismic isolation building 1 is demonstrated based on drawing.
As shown in FIG. 5, before excavating (primary drilling) the ground of the foundation portion (core foundation portion 2A, outer periphery foundation portion 2B) of the seismic isolation building 1 shown in FIG. The retaining wall 21 is installed by placing the retaining wall 21 at, for example, the well-known SMW (Soil Mixing Wall) method. That is, the outer peripheral base portion 2B is formed by primary excavation. Then, after primary excavation, the foundation pile 2 is driven at an appropriate position within the plane range of the seismic isolation building 1 using, for example, an earth drill method.
In addition, ground improvement is performed and the earth retaining part which functions as a soil formwork which does not use mountain retaining is formed in the slope 22 formed in the outer periphery of a primary excavating part (peripheral foundation part 2B).

  Next, excavation of board lowering part 2Ba of perimeter foundation part 2B is performed. The lower part 2Ba is provided in a plane area including the pile head 2a of the foundation pile 2 which is constructed closest to the core foundation 2A. Then, a temporary soil concrete 5 (see FIG. 2) is cast over the entire surface of the board lowering portion 2Ba. Specifically, as shown in FIG. 3, temporary temporary soil-to-earth concrete 5 is constructed by assembling the beam reinforcing bars 5a and the connecting reinforcing bars 5b of the temporary beam 5A and placing concrete. In addition, the beam reinforcement 5a and the connection reinforcement 5b are arranged so as to surround the pile head 2a located in the lower portion 2Ba described above in a plan view. Thereby, the end 5c (refer FIG. 2) by the side of the core foundation 2A of the temporary soil concrete 5 is connected to the upper end 21a of the retaining wall 21 and functions as a back anchor of the retaining wall 21 as described above.

  Then, after the placement of the temporary soil concrete 5 is completed, secondary excavation for excavating the inner ground surrounded by the retaining wall 21 is performed to form the core foundation 2A deeper than the outer periphery foundation 2B.

Next, as shown in FIG. 6, in the outer peripheral base portion 2B, the outer peripheral steel frame 4B of the core outer peripheral portion 1B is built, and a reinforced concrete mat slab 3B is driven. In the present embodiment, the mat slab 3B (the mat slab 3A of the core base portion 2A is also the same) is divided into upper and lower two layers and sequentially cast (see FIG. 7). That is, the mat slab 3B of the first layer (lower layer) is constructed in FIG. 6, and the mat slab 3B of the second layer (upper layer) is constructed in FIG.
In addition, also at the time of secondary excavation shown in FIG. 5, construction may be carried out simultaneously with the construction of the steel frame 4 (outer periphery steel frame 4B) of the ground floor of the core outer periphery 1B.

  Next, a temporary steel frame column 6 is erected on the pile head 2a of the foundation pile 2 on the outer peripheral side of the core foundation portion 2A (see FIG. 4). Then, the steel frame column 41 of the outer periphery steel frame 4B to which the temporary steel frame column 6 is connected is previously built at the lower end, and the steel frame column 41 is connected to the outer periphery steel frame 4B built on the outer periphery foundation 2B. Cast a slab 3A. That is, as shown in FIGS. 6 and 7, the temporary steel frame column 6 connected to the steel frame column 41 is built before the placement of the mat slab 3A. A portion of the temporary steel frame column 6 is embedded by the mat slab 3A.

  Next, as shown in FIG. 8, the intermediate seismic isolation device 7B is installed on the steel frame beam 42 (the position of the steel frame column 41 in a plan view) of the outer peripheral steel frame 4B provided on the ground part of the core outer peripheral part 1B. The intermediate seismic isolation device 7B is interposed between the upper steel frame 4 and the intermediate seismic isolation device 7B.

  Furthermore, the core seismic isolation device 7A is installed on the mat slab 3A of the core portion 1A. The core seismic isolation device 7A fixes the seismic isolation foundation 71 made of precast concrete on the mat slab 3A by appropriate fixing means such as anchor bolts, and the core seismic isolation device 7A is set on the seismic isolation foundation 71 . Since the steel frame 4 (core portion steel frame 4A) of the core portion 1A is also installed on the core vibration isolation device 7A, the core vibration isolation device 7A is between the mat slab 3A and the core portion steel frame 4A (see FIG. 1). To be intervened.

Next, as shown in FIG. 9, mounting concrete 3C for connecting the mat slab 3A cast in the core foundation 2A and the mat slab 3B cast in the outer periphery foundation 2B is cast. . The mounting concrete 3C embeds the upper end portion of the temporary steel frame column 6 located in the core foundation portion 2A and the lower end portion of the steel frame column 41 connected to the temporary steel frame column 6 with each other. Provided along the entire circumference.
Then, at the same time, the upper outer peripheral steel frame 4B of the intermediate seismic isolation device 7B is built.

  Subsequently, as shown in FIG. 10, the core steel frame 4A of the core 1A is erected in the core foundation 2A, and the upper steel frame 4 is further erected in the core 1A and the core outer periphery 1B ( See Figure 1).

Next, the operation of the above-described seismic isolation building and its construction method will be described in detail based on the drawings.
As shown in FIG. 2, in the present embodiment, temporary temporary concrete soil concrete 5 placed on the foundation bottom of the outer circumferential foundation portion 2B is connected to the upper end 21a of the retaining wall 21 provided on the core foundation portion 2A. The concrete 5 between soils functions as a back anchor of the retaining wall 21 and can be supported in tension on the opposite side to the direction in which the retaining wall 21 falls, thereby preventing the retaining wall 21 from falling.
Therefore, a cutting beam generally required to be provided on the retaining wall 21 of the core foundation portion 2A can be omitted, and the cost can be reduced.
And since earthwork and frame work of core part 1A can be constructed without receiving the influence of cutting beams, the work of cutting and lifting the cutting beams in the core foundation part 2A becomes unnecessary, and the construction period is shortened. be able to. In addition, since the cutting beams can be omitted, the reinforcing bars and the formwork of the seismic isolation foundation can be applied in advance in the foundation bottom of the excavated core foundation 2A.

  In addition, by providing temporary steel frame columns 6 immediately above the piles in the foundation bottom of the core foundation portion 2A, the temporary steel frame columns 6 are pre-formed on the outer peripheral portion steel frame 4B before placing concrete of the mat slab 3A on the core foundation portion 2A. Since it is possible to connect to the steel frame column 41, the work of erecting a permanent steel column base on the temporary steel frame column 6 can be started early. That is, since it is possible to simultaneously carry out the earth work accompanying the concrete placing of the mat slab 3 in the core foundation portion 2A and the construction work of the steel frame 4 on the temporary steel frame column 6, the process can be shortened.

  Further, since the mat slab 3B is cast on the outer peripheral base portion 2B and the intermediate seismic isolation device 7B is provided on the outer peripheral steel frame 4B of the ground floor of the core outer peripheral portion 1B, the foundation excavated bottom of the outer peripheral base portion 2B There is no need to provide a foundation beam or seismic isolation device directly on the top, and the depth of the foundation excavated bottom can be kept small, and the amount of excavated soil and the number of frames can be reduced.

  Moreover, since the position of the bottom of the outer peripheral base portion 2B is a shallow position, it is possible to change the bottom of the ground for excavating the base to a height higher than the level of the normal water surface. In that case, drainage of ground water becomes unnecessary, and there is no need to provide drainage equipment, and work can be performed on the upper side of the surface of ordinary water, and other construction can be performed in the absence of groundwater. Has the advantage of improving

  Further, in the present embodiment, the earth retaining portion (the slope surface 22) of the outer periphery foundation portion 2B is constructed by ground improvement, and the ground surface 22 of the outer periphery foundation portion 2B is improved at the time of primary excavation, and is used as a soil formwork As it becomes possible to function, it is possible to omit a pile pin (parent pile lateral arrow plate) and a cutting beam, and to reduce the cost.

Further, in the present embodiment, since the seismic isolation foundation 71 of the core seismic isolation device 7A of the core portion 1A is formed of precast concrete, the core seismic isolation is performed after the placement of the mat slab 3A in the core foundation portion 2A. The installation time of the seismic isolation foundation 71 of the device 7A can be shortened.
Further, since the seismic isolation foundation 71 is made of precast concrete, the construction accuracy can be improved as compared with the case of construction at a site.

  As described above, in the seismic isolation building according to the present embodiment and the construction method thereof, the number of underground excavations is reduced by reducing the seismic isolation base portion in the underground, and the cost and construction period for construction are reduced. It is possible to secure the construction quality.

As mentioned above, although embodiment of the seismic isolation building by this invention and its construction method were described, this invention is not limited to said embodiment, It can change suitably in the range which does not deviate from the meaning.
For example, in the present embodiment, although the earth retaining portion (the slope surface 22) of the outer peripheral foundation portion is constructed by ground improvement, the present invention is not limited to this, and a general earth retaining wall is used It is also good.

  Moreover, in this embodiment, although what was formed with a product made from precast concrete is used as the base isolation base 71 of the core seismic isolation apparatus 7A, and it is set as the structure fixed on mat slab 3A of the core foundation part 2A, it is precast concrete It does not matter even if it is the structure by construction by site casting in place of production.

The depths of the core base portion 2A and the outer peripheral base portion 2B can be appropriately set according to the shape of the building and the conditions of the floor height.
In addition, it is possible to appropriately set the configuration such as the number, the shape, the specification, and the installation position of the core seismic isolation device 7A and the intermediate seismic isolation device 7B.

  In addition, without departing from the spirit of the present invention, it is possible to replace components in the above-described embodiment with known components as appropriate.

DESCRIPTION OF SYMBOLS 1 seismically isolated building 1A core part 1B core outer peripheral part 2 foundation pile 2A core foundation part 2B outer peripheral base part 2Ba board down part 3, 3A, 3B mat slab 4 steel frame 4A core part steel frame 4B outer peripheral part steel frame 5 temporary construction earth concrete 5A temporary beam 6 temporary steel frame column 7A core seismic isolation device 7B intermediate seismic isolation device 21 pile wall 22 slope 41 steel frame column 42 steel frame beam 71 seismic isolation foundation M1 foundation seismic isolation layer M2 intermediate seismic isolation layer

Claims (4)

It is a seismically isolated building in which the core base supporting the core of the building has a base bottom deeper than the outer base supporting the core outer periphery of the building forming the outer periphery of the core,
Foundation piles placed on the core foundation and the outer periphery foundation;
A retaining wall provided as a retaining portion for the core foundation portion;
Temporary soil concrete that is connected to the upper end of the retaining wall and is embedded with a connecting rebar, while functioning as a main installation by being embedded in a mat slab cast in the outer peripheral foundation portion
A temporary beam which is provided in the outer peripheral foundation portion and in which a beam reinforcing member is embedded integrally with the temporary soil concrete via the connection reinforcing rod;
A temporary steel frame pillar which is provided on the foundation bottom of the core foundation portion and which is functioned as a permanent installation by being embedded in a mat slab driven on the core foundation portion;
A core seismic isolation device provided on a mat slab of the core base portion;
An intermediate seismic isolation device provided on a steel frame on the ground floor of the core outer peripheral portion ;
The beam reinforcing bars and the connection reinforcing bars are arranged so as to surround a pile head of the foundation pile which is disposed between the temporary beam and the retaining wall in the outer peripheral foundation portion. Seismic isolation building.   The base isolation building according to claim 1, wherein the base isolation foundation of the core base isolation device is formed of precast concrete. A core foundation portion supporting a core portion of a building is a construction method of a seismic isolation building having a structure in which a foundation bottom is deeper than a peripheral foundation portion supporting a core outer peripheral portion of a building forming an outer peripheral portion of the core portion,
Placing a foundation pile on the core foundation portion and the outer periphery foundation portion;
Providing a retaining wall as a retaining portion of the core foundation portion;
Placing concrete reinforcing bars by placing concrete and placing temporary concrete between soils that functions as a main facility by being buried in a mat slab placed in the outer peripheral foundation portion;
A step of providing a temporary beam by embedding concrete in the outer peripheral foundation portion to embed a beam rebar integrally with the temporary soil concrete via the connection reinforcing bar;
Connecting a portion of the temporary soil concrete to the upper end of the retaining wall;
Providing a temporary steel frame column at the base bottom of the core base section, and embedding the temporary steel frame column in a mat slab driven in the core base section to function as a permanent installation;
Providing a core seismic isolation device on the mat slab of the core foundation;
Providing an intermediate seismic isolation device on the steel frame of the ground floor of the core outer peripheral portion;
I have a,
The beam reinforcing bars and the connection reinforcing bars are arranged so as to surround a pile head of the foundation pile which is installed between the temporary beam and the retaining wall in the outer peripheral foundation portion. Construction method of seismic isolation building.   The earth retaining part of the said outer periphery foundation part is constructed by ground improvement, The construction method of the seismic isolation building of Claim 3 characterized by the above-mentioned.

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