JP2001032570A - Construction of vibration isolation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the construction of effective vibration isolation in which an excellent vibration-isolation effect even in a soft ground and a liquefied ground is obtained. SOLUTION: In the construction of vibration isolation in which a building 5 is borne by bearing piles 2 (2a, 2b) through vibration isolation devices 4, raking piles 2b are adopted as at least parts of the bearing piles 2. The raking piles 2b are installed in an outward spread radial shape in a plan view as pile groups 8 in which at least three or more are paired. A rotary jacked steel-pipe pile pressed into a ground by obtaining propulsive force in the penetration direction by a blade 9 by rotating a steel pipe in which the blade 9 is mounted at a front end section is used as the raking pile 2b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic isolation structure for obtaining a seismic isolation effect by lengthening a building, and more particularly to a seismic isolation structure suitable for a building constructed on soft ground or liquefied ground.

[0002]

2. Description of the Related Art As is well known, seismic isolation structures have been widely adopted in recent years, in which the entire building is supported by seismic isolation devices such as laminated rubber to reduce the seismic response by prolonging the period. .

[0003]

By the way, when the seismic isolation structure is applied to soft ground or liquefied ground, a sufficient seismic isolation effect cannot be obtained as compared to the case where the seismic isolation structure is applied to solid ground. is assumed.

[0004] That is, when a building is provided on soft ground or liquefied ground, it is usual to provide a support pile for supporting the vertical load of the building. However, soft ground or liquefied ground has a horizontal rigidity during an earthquake. The supporting piles that are small and therefore mounted on such ground must be designed on the premise that they behave as cantilevers due to the inertia of the superstructure. And the supporting pile which behaves as such a cantilever moves in the same way as the superstructure in the event of an earthquake, and does not cause much relative displacement between them, so even if a seismic isolation device is interposed between them It may not be able to operate satisfactorily, and therefore it may not be possible to obtain a sufficient seismic isolation effect.

[0005] Such a problem can be solved by increasing the horizontal rigidity of the support pile. However, in this case, a large cross section of the support pile causes a significant increase in cost, and inherently supports a vertical load. It is also unreasonable to provide an excessive level of rigidity to the support piles that need to be done (thus requiring high axial stiffness, but not so much horizontal stiffness).

[0006] In view of the above circumstances, an object of the present invention is to provide an effective seismic isolation structure capable of obtaining an excellent seismic isolation effect even on soft ground or liquefied ground.

[0007]

According to a first aspect of the present invention, in a seismic isolation structure in which a building is supported by a supporting pile via a seismic isolation device, an oblique pile is adopted as at least a part of the supporting pile. It becomes.

According to a second aspect of the present invention, there is provided the seismic isolation structure according to the first aspect of the present invention, wherein the slanted piles are provided as a group pile having at least three or more slanted piles in a radially outwardly expanding shape in plan view. Things.

A third aspect of the present invention is the seismic isolation structure according to the first or second aspect of the present invention, wherein the inclined pile is formed by rotating a steel pipe having a tip provided with a blade, so that the blade penetrates in the penetration direction. It is made by using a rotary press-fit steel pipe pile that presses into the ground by obtaining force.

[0010]

1 and 2 are schematic diagrams of a base isolation structure according to an embodiment of the present invention. In the figure, reference numeral 1 denotes a soft ground, reference numeral 2 (2a, 2b) denotes a support pile, reference numeral 3 denotes a bottom plate constituting a seismic isolation pit, reference numeral 4 denotes laminated rubber as a seismic isolation device, and reference numeral 5 denotes a building. The support pile 2 reaches the support ground 6 and supports the vertical load of the building 5 via the base 3 and the seismic isolation device 4, and the one located at the outermost periphery of the building 5 as shown in the drawing is usually used. The vertical stake 2b is adopted as the vertical stake 2a.

The inclined piles 2b are installed with a slight inclination with respect to the vertical. In the present embodiment, at least three inclined piles 2b are provided inside the building 5 as shown in FIG. The pile heads are provided as a group pile 8 integrated with a footing 7 in such a manner that the pile heads are provided radially outwardly at equal intervals, and the footing 7
Are integrated with the bottom plate 3. Such a slanted pile 2b exhibits excellent horizontal rigidity as compared with a vertical pile having the same cross section, since the horizontal component of the axial strength is resistant to the horizontal load. And, since each group pile 8 is provided radially as one set of three slant piles 2b, this substantially constitutes a part of the space truss structure, and is arranged in the whole horizontal direction by the truss effect. In contrast, it exhibits high rigidity.

In this embodiment, a rotary press-fit steel pipe pile is used as each inclined pile 2b. The rotary press-fit steel pipe pile has a configuration in which a steel pipe provided with a blade 9 at its tip is rotated by an auger machine or the like to obtain a propulsive force in the press-fit direction by the blade 9 and press-fit into the ground. The pile can be constructed with no earth removal, and has excellent support force and pull-out resistance by the blades 9. In addition, by filling the steel pipe with concrete, a filled steel pipe concrete pile having more rigidity and strength can be obtained.

The group pile 8 includes four or more slant piles 2b.
Of course, it is also good. In addition, the above vertical pile 2
a may be omitted and all the support piles 2 may be replaced with the inclined piles 2b.

According to the above structure, the inclined pile 2b used as the support pile 2 naturally has a higher horizontal rigidity than the vertical pile 2a, so that the natural period of the pile structure including the base 3 is naturally shorter. The difference in the natural period from the building 5 supported by the seismic isolation device 4 and lengthened becomes remarkable, and therefore, during an earthquake, the seismic isolation device 10 operates reliably and the building 5
Can be efficiently and effectively obtained. Therefore, there is no need to excessively design the cross section of the normal vertical pile 2a in order to increase the rigidity, which is advantageous in terms of cost and easy to design.

[0015]

According to the first aspect of the present invention, in a seismic isolation structure in which a building is supported by a supporting pile via a seismic isolation device, an oblique pile is employed as at least a part of the supporting pile, so that the vertical section having the same cross section is used. Compared to piles, the horizontal rigidity can be naturally increased, and the natural period is naturally short, so that the difference in natural period with the building can be secured large, and therefore the response reduction effect of the seismic isolation device is efficient and effective It is particularly suitable for application to buildings constructed on soft ground or liquefied ground.

According to the second aspect of the present invention, since the group piles each including at least three or more slant piles are radially provided so as to extend outward in a plan view, the horizontal rigidity is uniformly increased in all horizontal directions. Can be.

According to a third aspect of the present invention, a rotary press-fit steel pipe pile is used as a slanted pile, in which a steel pipe provided with a blade at its tip is rotated to obtain a propulsive force in a penetrating direction by the blade and press-fit the ground. The sloped pile can be constructed without noise, no vibration, and no earth removal, as well as excellent supporting force and pull-out resistance by the blades, and more rigidity and strength by filling the steel pipe with concrete. It is also possible to make a filled steel pipe concrete pile excellent in quality.

[Brief description of the drawings]

FIG. 1 is an elevation view showing an outline of a base isolation structure according to a first embodiment of the present invention.

FIG. 2 is a plan view showing a configuration example of the group pile.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Soft ground 2 Support pile 2a Vertical pile 2b Oblique pile 3 Base 4 Seismic isolation device 5 Building 6 Support ground 7 Footing 8 Group pile

Claims (3)

[Claims] 1. A seismic isolation structure in which a building is supported by a supporting pile via a seismic isolation device, wherein a slanted pile is adopted as at least a part of the supporting pile. 2. The seismic isolation structure according to claim 1, wherein said slanted piles are provided as a group of at least three or more piles as a group and radially spread outward in plan view. . 3. The seismic isolation structure according to claim 1 or 2, wherein the slanted pile is pressed into the ground by rotating a steel pipe provided with a blade at a tip portion to obtain a propulsive force in a penetrating direction by the blade. A seismic isolation structure characterized by using a rotary press-fit steel pipe pile.