JP3064887B2 - Seismic isolation structure of pile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a seismic isolation structure for a pile supporting a structure.

[0002]

2. Description of the Related Art A pile foundation is one of the types of foundation adopted when a high-quality support layer is deep underground. By constructing an upper structure on a pile driven into the support layer, The weight of the structure can be stably supported by the support layer.

[0003] Such a pile tends to have a relatively weak point against horizontal force due to its structural characteristics, and in the event of an earthquake, a large horizontal force or bending moment acts on the pile head from the upper structure.
Therefore, when designing piles, sufficient consideration is given to seismic loads.

[0004]

However, when an extremely large earthquake is encountered, an excessive horizontal force or bending moment acts on the pile head, and unexpected situations such as breakage of the pile and collapse of the superstructure may occur. May be invited.

The present invention has been made in view of the above circumstances, and has as its object to provide a seismic isolation structure for a pile capable of preventing the pile from being destroyed by a horizontal force or a bending moment from an upper structure. Aim.

[0006]

According to a first aspect of the present invention, there is provided a pile seismic isolation structure according to the present invention, wherein a footing installed on a group pile is attached to the head of the group pile. The lower footing fixed to the lower footing and the upper footing disposed above the lower footing are formed separately, and a lower slide pedestal formed by erecting a band plate around a substantially circular bottom plate is attached to the upper end of the lower footing. At the lower end of the upper footing, an upper sliding pedestal having a band plate erected around a substantially circular top plate is attached, and the top plate of the upper sliding pedestal and the bottom plate of the lower sliding pedestal are used as sliding surfaces. A spherical rolling element is loaded between the lower slide pedestal and the upper slide pedestal so as to roll, and an outer peripheral surface of a band plate of the upper slide pedestal and a band plate of the lower slide pedestal. Ring-shaped damper with the inner peripheral surface of the In which is fitted into the wood.

[0007]

In the seismic isolation structure for a pile according to the first aspect of the present invention, the relative movement between the upper footing and the lower footing is allowed during an earthquake, and the seismic energy input from the ground to the upper structure and the pile head from the upper structure. The horizontal force and bending moment acting on the surface are greatly reduced. In addition, a damper member is disposed between the two pedestals, and during an earthquake, vibration energy of the upper structure is absorbed by the damper member.

[0009]

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a seismic isolation structure for a pile according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an overall view showing a seismic isolation structure for a pile according to this embodiment. As can be seen from the figure, the pile seismic isolation structure according to the present embodiment includes a pile-side sliding pedestal 2 attached to the head of the pile 1 and a footing-side sliding pedestal 4 attached to the lower surface of the footing 3. Between the pile-side sliding base 2 and the footing-side sliding base 4.
And a damper member 6 is disposed between them.

As can be clearly seen from the exploded perspective view of FIG. 2, the pile-side slide base 2 has a substantially circular bottom plate 1 on which the rolling elements 5 roll.
1, a foot plate 13 having a substantially circular top plate 13 on which the rolling element 5 rolls.
And a band plate 14 is provided upright. The upper surface of the bottom plate 11 and the lower surface of the top plate 13 are preferably coated with, for example, Teflon material so that the rolling friction of the rolling elements 5 is as small as possible.

As shown in FIG. 1, the pile-side sliding pedestal 2 secures the anchor bar 15 fixed to the lower surface of the bottom plate 11 and the main bar 16 of the pile 1 to the concrete 7 by fixing the same to the concrete 7.
Similarly, the footing-side slide pedestal 4 is provided with an anchor stud 17 fixed to the upper surface of the top plate 13.
Is firmly fixed to the footing 3 by fixing it to the concrete of the footing 3.

The damper member 6 is formed in a ring shape as shown in FIG. 2 using, for example, high-damping rubber, and has an outer peripheral surface of the band plate 14 of the footing-side slide pedestal 4 and the pile-side slide pedestal 2. Between the inner peripheral surface of the band plate 12 and the inner peripheral surface. In addition, it is possible to prevent water permeation to the vicinity of the rolling element 5 by forming the damper member 6 itself from a water-stopping material and providing a predetermined seal in a gap between the member 6 and both pedestals to form a sealed structure. Good.

The rolling element 5 rolls with the top plate 13 and the bottom plate 11 as sliding surfaces while transmitting an axial force between the footing-side sliding pedestal 4 and the pile-side sliding pedestal 2 to move in the horizontal direction. Can be insulated. Grease is preferably sealed in the footing-side slide pedestal 4 to prevent the rolling elements 5 from rusting.

In the seismic isolation structure for a pile according to the present embodiment, the pile-side sliding pedestal 2 attached to the head of the pile 1 and the footing-side sliding pedestal 4 attached to the lower surface of the footing 3. The pile 1 and the footing 3 are loaded with spherical rolling elements 5 regardless of the direction of vibration caused by the earthquake.
The seismic energy input from the ground to the superstructure and the horizontal force and bending moment acting on the pile head from the superstructure are greatly reduced.

Further, a ring-shaped damper member 6 is disposed between the two pedestals, and the vibration energy of the upper structure and the footing can be obtained as shown in FIG. 3 regardless of the vibration direction. Is absorbed by the damper member 6.

As described above, according to the seismic isolation structure for a pile of the present embodiment, the rolling elements are arranged between the head of the pile and the footing, so that the seismic energy input from the ground to the upper structure is greatly increased. The upper structure is seismically isolated, and the horizontal force and bending moment acting on the pile head from the upper structure are significantly reduced, thus preventing the pile from being damaged. Further, since the ring-shaped damper member is employed, the vibration of the upper structure can be attenuated in all vibration directions.

When footings are installed on so-called group piles, a structure as shown in FIG. 4 may be used instead of arranging rolling elements or the like on the head of each pile and the lower surface of the footing.

That is, the seismic isolation structure of the pile shown in FIG.
The footing 3 installed on the group pile 21 is divided into a lower footing 22 fixed to the head of the group pile 21 and an upper footing 23 disposed thereabove, and the upper end of the lower footing 22 and the upper footing 22 are formed. 23, a lower slide base 24 and an upper slide base 25 are respectively attached to the lower slide base 24 and the upper slide base 25.
And a damper member 6 is disposed between the pedestals.

The lower slide pedestal 24 has substantially the same configuration as the pile-side slide pedestal 2, and the anchor bar 15 fixed to the lower surface of the lower slide pedestal 22 is fixed in the concrete of the lower footing 22 so as to be fixed to the lower footing 22. It is fixed firmly. Similarly, the upper slide pedestal 25 has substantially the same configuration as the footing-side slide pedestal 4, and the anchor stud 17 fixed to the upper surface thereof is fixed in the concrete of the upper footing 23, so that the upper footing 23 is fixed to the upper footing 23. It is fixed firmly.

In the seismic isolation structure of such a pile, the relative movement between the upper footing 23 and the lower footing 22 is allowed during an earthquake, and the seismic energy input from the ground to the upper structure and the group pile 21 from the upper structure are removed. The horizontal force and bending moment acting on the head are greatly reduced, seismic isolation of the upper structure and prevention of damage to the group piles can be achieved, and vibration of the upper structure can be reduced by the ring-shaped damper member 6 It can be attenuated in the vibration direction.

[0023]

As described above, according to the seismic isolation structure for a pile according to the first aspect of the present invention, it is possible to prevent the group pile from being broken by a horizontal force or a bending moment from the upper structure. it can.

[0024]

[0025]

[Brief description of the drawings]

FIG. 1 is a side view showing a seismic isolation structure of a pile according to an embodiment.

FIG. 2 is an exploded perspective view of the same.

FIG. 3 is an explanatory view showing the operation of the seismic isolation structure of the pile according to the embodiment.

FIG. 4 is a side view showing a seismic isolation structure of a pile according to a modification of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pile 2 Pile side sliding pedestal 3 Footing 4 Footing side sliding pedestal 5 Rolling element 6 Damper member 21 Group pile 22 Lower footing 23 Upper footing 24 Lower sliding pedestal 25 Upper sliding pedestal

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) E02D 27/12 E02D 27/34 E04H 9/02 331

Claims (1)

(57) [Claims] 1. A footing installed on a group pile is divided into a lower footing fixed to the head of the group pile and an upper footing disposed above the lower part, and a substantially circular shape is formed at an upper end of the lower footing. Attach a lower slide pedestal with a band plate erected around the bottom plate and attach an upper slide pedestal with a band plate erected around a substantially circular top plate at the lower end of the upper footing. A spherical rolling element is loaded between the lower slide pedestal and the upper slide pedestal so as to roll with the top plate of the upper slide pedestal and the bottom plate of the lower slide pedestal as sliding surfaces, and A seismic isolation structure for a pile, wherein a ring-shaped damper member is fitted between the outer peripheral surface of the strip of the upper slide pedestal and the inner peripheral surface of the strip of the lower slide pedestal. .