JPH11269847A - Pier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the maximum bending moment acting on support legs by installing a floor framing of a pier on the heads of support legs through base isolation dampers. SOLUTION: A concrete floor framing 2 is supported by support legs 4 made of steel pipe piles 3 to constitute a pier 1. Longer beams 6a in the longitudinal direction and shorter beams 6b in the lateral direction are provided in the underface of the floor boards 5 so as to form a lattice, in the floor framing 2. The beams 6a, 6b are connected to the heads of the piles 3 driven in a support bed rock 8 through base isolation dampers 7. Circular steel plates and circular rubber layers are alternately overlaid for instance in the damper 7, and an upper end plate and a lower end plate larger than the steel plates are provided respectively. The upper end plate is fixed to the base of the beam 6a and the lower end plate is fixed to the base provided at the heads of the piles 3 with bolts. In this way, as a base isolation damper is forcibly deformed to absorb horizontal forces in an earthquake, a bending moment acting on the support legs can be remarkably reduced and the diameter of the support legs can be lessened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pier having a floor set supported by steel pipe piles or the like.

[0002]

2. Description of the Related Art As shown in FIG. 6, many conventional piers have a structure in which a floor set 22 is supported by pillars 21 such as steel pipe piles. The pier 20 has a structure that supports vertical loads with pillars 21 and also resists horizontal external force during an earthquake. Therefore, in the event of an earthquake, the floor set 22 and the pillar 2
The maximum bending moment occurs near the joint of No. 1 and at a position 1 / β from the sea floor, and the required pillar diameter is determined from this magnitude. The above β is calculated by the equation shown in FIG.

[0003]

The pier as described above is
Since the required pillar diameter is determined by the maximum bending moment acting on the pillar, the diameter must be increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to reduce the load on the pillar by reducing the maximum bending moment acting on the pillar, and to reduce the required pillar diameter. Is to be significantly reduced.

[0005]

According to a first aspect of the present invention, there is provided a pier having a floor set supported by pillars, wherein the floor set is connected to a pillar capital through a seismic isolation damper. It is characterized by being installed in the department.

According to the first aspect of the present invention, the seismic isolation damper is forcibly deformed during an earthquake to absorb horizontal force and greatly reduce the bending moment acting on the pillar.

According to a second aspect of the present invention, in the first aspect, the seismic isolation damper is formed by stacking a steel plate and a rubber plate alternately.

According to the invention of claim 2, the seismic isolation damper can be attached to the steel pipe pile head when constructing a new pier.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of a pier according to the present invention will be described in detail with reference to the drawings. 1 is a longitudinal sectional view of the pier, FIG. 2 is a sectional view taken along the line AA of FIG. 1, FIG.
FIG. 3 is a sectional view taken along line BB of FIG.

The pier 1 comprises a concrete floor set 2 supported by pillars 4 of a steel pipe pile 3. In the floor set 2, a long beam 6a in the long side direction and a short beam 6b in the short side direction are formed on the lower surface of the floor plate 5 in a lattice shape, and the steel pipe pile 3 Are joined through. The steel pipe piles 3 are arranged in three rows in a row of five and are piled on the support base 8.

The seismic isolation damper 7 is formed by laminating a circular steel plate 9 and a circular rubber layer 10 alternately, and is provided with upper and lower plates 11 and 12 larger than the steel plate 9 on the upper and lower surfaces, respectively. ing. And the upper end plate 11
Are fixed to the base 13 of the long beam 6a, and the lower end plate 12 is fixed to the base 14 of the pile head with bolts 15, respectively. The mounting location of the seismic isolation damper 7 is determined by the burden rate of the horizontal force during the earthquake.

When the earthquake occurs, the seismic isolation damper 7 mounted between the pile head and the floor set 2 absorbs the horizontal force by being forcibly deformed and reduces the load on the steel pipe pile 3.

FIG. 4B shows the maximum bending moment generated in the steel pipe pile 3 when the seismic response analysis is performed at the pier 1 shown in FIG. is there. According to this, the maximum bending moment from the pile head to 1 / β is reduced to about １ ／ as compared with a conventional pier (the pier 20 shown in FIG. 6 without the seismic isolation damper).

FIG. 5 shows the relationship between the natural period Tm and the response acceleration of the floor group, with the horizontal axis representing the natural period and the vertical axis representing the response acceleration of the floor group. According to this, when the natural acceleration of the conventional pier 20 (FIG. 6) is T = 0.6 seconds, the response acceleration of the floor group is about 600 gal,
The natural period of the pier 1 (FIG. 1) of the present invention is about 150 gal when T = 1.8 seconds, which is reduced to about 1/4. Therefore, in the pier 1 of the present invention, the penetrating force acting on the pile head from the floor set 2 is also reduced to about 1/4. From the above, the following effects of the present invention could be confirmed.

[0015]

According to the present invention, the seismic isolation damper is forcibly deformed in the event of an earthquake, thereby absorbing the horizontal force and greatly reducing the bending moment acting on the pillar, thereby reducing the diameter of the pillar.

When a new pier is constructed, the seismic isolation damper can be attached to the steel pipe pile head.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a pier.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3A is a cross-sectional view of a state where a seismic isolation damper is attached, and FIG. 3B is a cross-sectional view taken along line BB of FIG.

4A is a longitudinal sectional view of a pier, and FIG. 4B is a graph showing a maximum bending moment generated in a steel pipe pile.

FIG. 5 is a graph showing a relationship between a natural period and a response acceleration of a floor group.

FIG. 6 is a longitudinal sectional view of a conventional pier.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 20 Pier 2, 21 Floor set 3 Steel pipe pile 4, 22 Pillar 5 Floor plate 6a Long beam 6b Short beam 7 Seismic isolation damper 8 Support base 9 Steel plate 10 Rubber layer 11 Upper plate 12 Lower plate 13, 14 Base 15 Bolt

Claims (2)

[Claims] 1. A pier having a floor set supported by pillars, wherein the floor set is installed on a pillar head via a seismic isolation damper. 2. The pier according to claim 1, wherein the seismic isolation damper is constituted by laminating steel plates and rubber layers alternately.