JP2008303587A - Top-down construction method for base-isolated building - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a top-down construction method for a base-isolated building, in which desired base isolation action can be expected by means of a base isolation device by preventing a head part of an underground steel column structure from displacing in the horizontal direction and preventing the generation of initial stress acting on the base isolation device. <P>SOLUTION: In this top-down construction method for the base-isolated building, an earth retaining wall 1 is constructed at an outer peripheral position of the base-isolated building B to be constructed, a plurality of underground steel column structures 3 for installing the base isolation device 2 on their head parts are constructed in the ground G below columns B1 of the base-isolated building B, then the ground G below the head parts of the underground steel column structures 3 is dug and the dug-up soil is removed, and a skeleton 6 of a lower part structural body is constructed below the base isolation device 2. After constructing a plurality of the underground steel column structures 3 into the ground G, the sections in the vicinity of the head parts of a plurality of the underground steel column structures 3 are mutually connected by position regulating members 5, and then the ground G below the head parts of a plurality of the underground steel column structures 3 is dug and the dug-up soil is removed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention constructs a retaining wall at the outer peripheral position of the seismic isolation building to be constructed, and has a plurality of built-up columns for installing a seismic isolation device on the head in the lower ground of the column of the seismic isolation building. It is related with the reverse striking method of the seismic isolation building which excavates the ground below the head of the said structure pillar, excavates it, and constructs the frame of a lower structure below the said seismic isolation apparatus.

  Conventionally, the reverse method of such a base-isolated building has been to excavate holes larger in diameter than the structural pillars at the locations where a plurality of structural pillars should be built, and to place concrete in each of these holes. The seismic pillar is constructed and inserted before it is hardened, and then the seismic isolation building planned to be installed on the seismic isolation device installed on the head of the structural pillar. There is known a construction method for constructing the lowermost frame and excavating the ground below the head of the structural pillar and discharging the soil (for example, see Patent Document 1).

Japanese Patent No. 2950325

  However, in the conventional method described in the above-mentioned patent document, the head side of each structural pillar is in a self-supporting state in the hole for the structural pillar, so it is exempted on the seismic isolation device installed on the head of the structural pillar. When constructing the lowermost frame of the seismic building, the head of the structural pillar may be displaced in the horizontal direction unexpectedly. If the lowermost frame of a base-isolated building is constructed with the head of the true column displaced in the horizontal direction, it is unnecessary for the seismic isolation device interposed between the lowermost frame and the head of the main column. Since the initial stress is applied, the seismic isolation effect of the seismic isolation device is adversely affected, and the desired seismic isolation function may not be expected.

  The present invention pays attention to such a conventional problem, and its purpose is to suppress the horizontal displacement of the head of the structure column, thereby suppressing the initial displacement acting on the seismic isolation device, An object of the present invention is to provide a reverse driving method for a base-isolated building that can be expected to have a base-isolating action as desired.

  A first characteristic configuration of the present invention is that a mountain retaining wall is constructed at an outer peripheral position of a seismic isolation building to be constructed, and a plurality of structural pillars for installing a seismic isolation device on its head are provided as the seismic isolation building. Of the seismic isolation building which is built in the lower ground of the pillar of the building, and then excavates and evacuates the ground below the head of the structural pillar, and constructs the frame of the lower structure below the seismic isolation device. In the reverse driving method, after the plurality of structural pillars are built in the ground, the vicinity of the heads of the plurality of structural pillars are connected to each other by a position regulating member, and then the plurality of structural pillars are connected. It is in the place where the ground below the head of the construction pillar is excavated and discharged.

According to the first characteristic configuration of the present invention, after the plurality of structural pillars are built in the lower ground of the pillars of the seismic isolation building, the positions near the heads of the plurality of structural pillars are positioned. For example, in the case of the conventional method described above, even if the head side of each structural pillar is in a self-supporting state in the hole for the structural pillar, each structural pillar is The horizontal displacement in the vicinity of the head is suppressed.
In addition, if the structural column is to be built directly in the lower ground of the seismic isolation building pillar without constructing the structural column, first, the position control members are located near the heads of the multiple structural columns. Are connected to each other, and then the ground below the heads of the plurality of structural pillars is excavated and evacuated. The displacement in the direction is suppressed.
Therefore, in any case, the horizontal displacement of the head of the stem column is suppressed, and as a result, the initial stress acting on the seismic isolation device is suppressed, and the seismic isolation operation as desired by the seismic isolation device. Can be expected.

  The 2nd characteristic structure of this invention exists in the place which connects the said position control member to the said retaining wall.

  According to the second characteristic configuration of the present invention, the position regulating member is connected not only to the vicinity of the heads of the plurality of structural pillars but also to the retaining wall constructed at the outer peripheral position of the seismic isolation building to be constructed. In addition, the horizontal displacement in the vicinity of the head of each structural pillar is further reliably suppressed, and the displacement of the retaining wall is also suppressed.

  A third characteristic configuration of the present invention is that the position regulating member is a floor board.

According to the third characteristic configuration of the present invention, since the position regulating member is a floor board, the floor board can be used as a working floor, and various operations are performed above and below the floor board, respectively. It is possible to proceed separately, and work efficiency can be improved.
In addition, you may leave the floor board after work, and may use it as a part of the frame of a seismic isolation building.

  A fourth characteristic configuration of the present invention is that the position regulating member is a beam.

  According to the fourth characteristic configuration of the present invention, since the position restricting member is a beam, it can be used as a part of the frame of the base-isolated building by leaving the beam, and the position restricting member is a temporary member. In some cases, the removal operation can be easily performed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a reverse construction method for a base-isolated building according to the present invention will be described with reference to the drawings.
In the reverse driving method of the present invention, first, as shown in FIG. 1, the retaining wall 1 is constructed so as to be positioned on the outer periphery of the base isolation building B in the ground G below the base isolation building B to be constructed. The retaining wall 1 is usually composed of a pillar pile made of concrete or a continuous wall, but can also be composed of other wall bodies.
Next, a plurality of structural pillars 3 for installing the seismic isolation device 2 on its head are built in the ground G below the column B1 of the seismic isolation building B to be constructed. The construction of the structural pillar 3 is performed by, for example, excavating a hole G1 for a structural pillar having a diameter larger than that of the structural pillar 3 at a position where the structural pillar 3 is to be built, and placing concrete in the hole G1. And then constructing the pedestal column 4 and inserting the pedestal column 3 into the pedestal column 4 before the pedestal column 4 is hardened. Build to be one. It should be noted that the construction pillar 3 can be inserted into the hole G1 either before or after the concrete placement.

Thereafter, as shown in FIG. 2, the ground G surrounded by the retaining wall 1 is excavated and soiled until at least the vicinity of the heads of the plurality of structural pillars 3 is exposed, and at least the plurality of structural pillars 3 are removed. The vicinity of the heads are connected to each other by the position restricting member 5. Preferably, in addition to the vicinity of the heads of the plurality of structural pillars 3, the retaining wall 1 is also connected to each other by the position restricting member 5.
The position restricting member 5 is preferably composed of a concrete slab, a floor plate made of various steel materials, a beam made of concrete or steel material, or the like, but can also be composed of a turnbuckle or the like.
The position restricting member 5 is arranged in a lattice shape in a plan view as shown in FIG. 3 to connect the vicinity of the head of each structural pillar 3 and the retaining wall 1 to each other, or the entire surface in a plan view. Further, it can be arranged in other modes.

As shown in FIG. 4, the seismic isolation device 2 is directly installed on the head of each structural pillar 3 with the vicinity of the heads of the plurality of structural pillars 3 connected by the position regulating member 5 in this way. As shown in FIG. 5, the ground G below the head of the stem 3 is excavated and soiled, and a foundation slab 6 as a frame of the lower structure is constructed in the retaining wall 1.
In FIG. 4, the seismic isolation device 2 is directly installed on the head of each structural pillar 3. However, as shown in FIG. 7, the upper end of each structural pillar 3 terminates in the position regulating member 5. In this way, the position restricting member 5 may be arranged, and the seismic isolation device 2 may be installed on the position restricting member 5 corresponding to the head of each structural pillar 3.
And as shown in FIG. 6, the lowermost frame B2 of the base isolation building B to be constructed is constructed on each base isolation device 2, and the base isolation building B is constructed thereon.
It should be noted that either the foundation slab 6 or the lowermost frame B2 can be constructed in advance or at the same time. In addition, as described above, the seismic isolation device 2 is installed after the construction column 3 is installed, for example, the seismic isolation device 2 is installed in advance on the head of each construction column 3. It is also possible to build the structural pillar 3 on which the seismic isolation device 2 is installed in the ground G.

[Another embodiment]
In the previous embodiment, when constructing the structural pillar 3, first, the structural pillar 4 is constructed in the hole G1 for the structural pillar, and the structural pillar 3 is inserted before the structural pillar 4 is cured. However, it is also possible to directly insert each of the structural pillars 3 into the ground G without constructing the structural pillars 4.
Further, the position restricting member 5 can be left as it is and used as a part of the frame of the seismic isolation building B, or it can be constituted by a temporary member and finally removed.
As the seismic isolation device 2, various types of seismic isolation devices are used, including various types of seismic isolation devices such as laminated rubber bearings, sliding bearings, and rolling bearings. be able to.

Cross-sectional view showing the stage where the structural pillar was constructed in the reverse casting method of the base-isolated building Sectional drawing which shows the stage which connected the construction pillar by the position control member The top view which shows the step which connected the construction pillar by the position control member Sectional view showing the stage where seismic isolation devices are installed on the true pillar Sectional view showing the stage where the foundation slab was built in the retaining wall Sectional view showing the stage of building a base-isolated building Sectional drawing which shows the step which installed the seismic isolation apparatus in the structural pillar in another embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mountain retaining wall 2 Seismic isolation device 3 True column 5 Position control member 6 Substructure frame B Seismic isolation building B1 Base isolation building pillar G Ground

Claims (4)

While constructing a retaining wall at the outer peripheral position of the seismic isolation building to be constructed, install a plurality of structural pillars for installing the seismic isolation device on the head in the lower ground of the column of the seismic isolation building, After that, excavating the ground below the head of the structural pillar and excavating the soil, the reverse construction method of the seismic isolation building that constructs the lower structure frame below the seismic isolation device,
After the plurality of structural pillars are built in the ground, the vicinity of the heads of the plurality of structural pillars are connected to each other by a position restricting member, and then from the heads of the plurality of structural pillars. A reverse-strike method for base-isolated buildings that excavate and excavate the ground below.   2. The seismic isolation building reverse striking method according to claim 1, wherein the position restricting member is connected to the mountain retaining wall.   3. The reverse driving method for a seismic isolation building according to claim 1, wherein the position regulating member is a floor board.   The seismic isolation building reverse driving method according to claim 1, wherein the position regulating member is a beam.

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