JPH09142580A - Support structure of spherical tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the earthquake-resistance of a spherical tank to cope with a larger earthquake than the present earthquake-resistant standards. SOLUTION: A spherical tank 1 is supported by a plurality of support legs 2 erected at every distance on the installation face G of the spherical tank 1. A plurality of first wire fixing parts 11 are provided with a peripheral distance at the first level in the side face of the spherical tank 1 and also a plurality of second wire fixing parts 21 are provided at the second level. A plurality of supports 12 are erected on the installation face G at the horizontally outer side of the spherical tank and respective upper ends 12a of these supports are positioned nearly oppositely to the first wire fixing parts 11. The first wires 14 are stretched between the first wire fixing parts 11 and the upper ends of 12a of these supports 12 respectively and the second wires 23 are stretched between the second wire fixing parts 21 and the installation face G respectively.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a support structure for a spherical tank.

[0002]

As is well known, primary energy resources such as petroleum, LNG, and LPG are stored in storage tanks in order to secure a long-term stable supply. Storage tanks used in this type of field include aboveground tanks and underground tanks.

One of the forms of the aboveground tank is a spherical tank. The spherical tank 1 shown in FIG. 5 is generally a medium-capacity storage facility, and is supported by a plurality of support legs 2 standing upright along a virtual circle O on the installation surface G. A brace 4 is arranged between adjacent support legs 2 to enhance the integrity of the support legs 2 as a whole.

[0004]

By the way, in the support structure of the spherical tank shown in FIG. 5, a certain degree of seismic resistance is given by the integration of the support legs 2 by the braces 4. However, if there is a large earthquake that exceeds the current seismic resistance standard, for example, vertical seismic force acts on the supporting legs 2 due to vertical vibration, and lateral seismic force acts on lateral support. There is a possibility that the support leg 2 may be deformed.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a support structure for a spherical tank which improves the seismic resistance of the spherical tank.

[0006]

According to a first aspect of the present invention, there is provided a support structure for a spherical tank, wherein a plurality of first tanks are provided on a side surface of the spherical tank at a first height at intervals around a vertical axis of the spherical tank. One wire fixing part is provided and a plurality of second wire fixing parts are provided at a second height, and the second wire fixing parts are located on the installation surface in the horizontal direction outward of the spherical tank, and the upper ends of the two are fixed to the first position. A plurality of columns are erected so as to be substantially opposed to the wire fixing portion, the first wires are stretched between the first wire fixing portion and the upper ends of the respective columns, and each second wire fixing portion is provided. Between the installation surface and the installation surface in the vertical direction.
The wire is stretched.

In the support structure for a spherical tank according to claim 1, when the rolling due to the vibration of the ground is transmitted from the support structure for the spherical tank to the spherical tank, the spherical tank vibrates in the lateral direction. Has a shearing force in the direction parallel to the installation surface. Here, since the first wire is stretched in the direction of pulling the spherical tank radially outward from the periphery thereof, the shearing force acting on the supporting structure of the spherical tank is not limited to the supporting legs but also the first wire. Is also transmitted and distributed, and the shearing force acting on each support leg is reduced.

Further, the support column bends inside the imaginary circle when the first wire is pulled to the spherical tank side, but by returning due to the rigidity of the support column itself, it acts as a damper against the lateral vibration of the spherical tank. .

When the pitching due to an earthquake is transmitted from the support structure of the spherical tank to the spherical tank, the spherical tank vibrates in the vertical direction, so that a tensile force acts on the support structure of the spherical tank. Here, since the second wire is stretched in the direction of pulling the spherical tank toward the installation surface, the pulling force that acts on the support structure of the spherical tank is distributed not only to the support legs but also to the wire, and The tensile force acting on the supporting leg is reduced.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a support structure for a spherical tank according to the present invention will be described in detail with reference to FIGS. As shown in FIG. 1, the spherical tank 1 is supported by a plurality of support legs 2 standing upright on the installation surface G at equal intervals,
Braces 4 are provided so as to intersect between adjacent support legs 2.

As shown in FIG. 2, the grounding portion 2a of the support leg 2 is mounted on a base 5 embedded in the installation surface G and bolts 6 are mounted thereon.
It is fixed by. Further, one end 4a of the brace 4 is fixed to a plate 7 provided near the grounding portion 2a.

The supporting portion 2b of the supporting leg 2 is fixed to the outer shell of the spherical tank 1, as shown in FIG. Further, the other end 4b of the brace 4 is fixed to a plate 7 provided below the supporting portion 2b.

The side surface of the spherical tank 1 is shown in FIGS.
As shown in FIG. 7, the annular strip 10 is provided at a certain height (first height) along the circumferential direction below the supporting portion 2b of the supporting leg 2.
And the annular band plate 20 is disposed above the support portion 2b at a constant height (second height) along the circumferential direction. Both of these strips 10 and 20 are fixed to the surface of the spherical tank 1 by welding.

A plurality of first wire fixing portions 11 are provided on the strip plate 10 at equal intervals around the vertical axis of the spherical tank 1, and the strip plate 20 is also provided at equal intervals around the vertical axis of the spherical tank 1. The same number of second wire fixing portions 21 as the first wire fixing portions 11 are provided at intervals.

On the installation surface G, there are columns 12 that are located outside the spherical tank 1 in the horizontal direction, that is, outside the outline of the spherical tank 1 in the horizontal direction when viewed from above and have the same number of columns 12 as the first wire fixing portions 11. The spherical tank 1 is erected so that its upper end portion 12a faces the first wire fixing portion 11.

A wire fixing portion 13 is provided on the upper end portion 12a of the column 12, and a first wire 14 is stretched between the wire fixing portion 13 and the first wire fixing portion 11. The pillar 12 is set higher than the position where the strip 10 is arranged, and the first wire 14 is higher on the pillar 12 side.
It is arranged at a low inclination to the side of the strip 10.

The ground portion 12a of the column 12 is fixed to a base 5a embedded in the installation surface G. A wire fixing portion 22 is provided on the base 5a, and a second wire 23 is stretched between the wire fixing portion 22 and the second wire fixing portion 21. The second wire is arranged so as to be low on the base 5a side and highly inclined on the strip plate 20 side so as to intersect with the first wire.

In the support structure for a spherical tank constructed as described above, the first wire 14 together with the rigidity of the support column 12 urges the spherical tank 1 in the upward direction so that the second wire 23 Installs spherical tank 1 on surface G
The spherical tank 1 is supported while the load applied to the support leg 2 is reduced by urging each other in opposite directions in the vertical direction.

By the way, when the rolling due to an earthquake is transmitted from the support structure of the spherical tank to the spherical tank 1, the spherical tank 1
Oscillates laterally, so that a shearing force acts on the support structure of the spherical tank in a direction parallel to the installation surface G. Here, the first
Since the wire 14 is stretched in the direction of pulling the spherical tank 1 outward in the radial direction from the periphery thereof, the shearing force acting on the supporting structure of the spherical tank is applied not only to the support legs 2 but also to both sides in the vibration direction. The shearing force acting on the individual support legs 2 is also reduced by being transmitted and distributed to the first wire 14 located. Therefore, it is possible to prevent shearing, bending, and collapse of the support leg 2.

Moreover, the first wire 14 is the spherical tank 1.
When pulled to the side, the column 12 bends inside the imaginary circle O,
Since the pillar 12 itself returns due to its rigidity to act as a damper of the spherical tank 1, the lateral vibration of the spherical tank 1 can be absorbed.

Further, when the pitching due to an earthquake is transmitted from the spherical tank support structure to the spherical tank 1, the spherical tank 1 vibrates in the vertical direction, so that a tensile force acts on the spherical tank support structure. Here, the second wire 23 is the spherical tank 1
Is stretched in the direction of pulling toward the installation surface G, the tensile force that acts on the support structure of the spherical tank is transmitted not only to the support legs 2 but also to the second wires 23, and is distributed to the individual support legs 2. The working tensile force becomes small. Therefore, it is possible to prevent the support leg 2 from being divided or collapsed.

The support structure for the spherical tank described in the present embodiment is relatively simple in structure and does not require relocation or removal of each equipment of the spherical tank 1. Therefore, it should be installed on the existing spherical tank. Is also possible.

The dimensions of the strips 10 and 20 and the tensions applied to the first wire 14 and the second wire 23 respectively decrease the strength of the spherical tank 1 and the support legs 2 due to the weight of the strips 10 and 20. It is desirable to design in consideration of the above. Further, it is desirable that the rigidity of the column 12 is also appropriately set at the design stage so as to efficiently damp the vibration of the spherical tank.

[0024]

According to the support structure for a spherical tank of the present invention, since the first wire is stretched in the direction of pulling the spherical tank radially outward from the periphery thereof, the spherical tank can be damaged by an earthquake. The shearing force acting on the supporting structure is distributed not only to the supporting legs but also to the first wire, and the shearing forces acting on the individual supporting legs are reduced. Therefore, it is possible to prevent the supporting legs from shearing or collapsing and improve the seismic resistance of the supporting structure of the spherical tank. And the first
When the wire is pulled toward the spherical tank, the column bends inside the imaginary circle, but it returns due to the rigidity of the column itself and acts as a damper for the spherical tank, so it can absorb the lateral vibration of the spherical tank. it can. Further, since the second wire is stretched in the direction of pulling the spherical tank toward the installation surface, the tensile force that acts on the support structure of the spherical tank is transmitted not only to the support legs but also to the second wire, and is dispersed. The tensile force acting on each support leg is reduced. Therefore, it is possible to prevent the supporting legs from buckling or dividing and improve the earthquake resistance of the supporting structure of the spherical tank.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of a support structure for a spherical tank of the present invention.

FIG. 2 is a side view showing a grounding portion of a support leg.

FIG. 3 is a side view showing a joint portion of support legs.

FIG. 4 is a plan view of the support structure for the spherical tank shown in FIG. 1, viewed from above.

FIG. 5 is a perspective view showing an example of a conventional spherical tank.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spherical tank 2 Support leg 11 1st wire fixing | fixed part 12 Support | pillar 14 1st wire 21 2nd wire fixing | fixed part 23 2nd wire G Installation surface O Virtual circle

Claims (1)

[Claims] 1. A plurality of support legs are erected on an installation surface of the spherical tank along a virtual circle on the installation surface at intervals from each other, and the spherical tank is provided inside the support legs by the support legs. In a supporting structure for a spherical tank, which is supported, a plurality of first wire fixing portions are provided on a side surface of the spherical tank at a first height at intervals around a vertical axis of the spherical tank. A plurality of second wire fixing portions are provided at a second height, and the second wire fixing portions are located on the installation surface in a horizontal direction outward of the spherical tank, and upper ends of the second wire fixing portions are substantially opposed to the first wire fixing portion. A plurality of columns are erected, and the first wires are stretched between the first wire fixing portion and the upper ends of the columns, respectively, and the second wire fixing portions and the Install the second work in the vertical direction between the installation surface and The support structure of spherical tank, characterized in that Ya is stretched.