Seismic isolation structure of storage shed

Abstract

To propose a seismic isolation structure for a storage shelf and a cast iron support used for this, which makes it possible to reduce an earthquake damage with a simple mechanism for the movable storage shelf.SOLUTION: The present invention is a seismic isolation structure 1 for a storage shelf in which a cast iron support 3 is interposed between a column base part 23 of a support post 22 of the storage shelf 2 and a concrete floor surface 4. The support 3 is composed of a member having a triangular columnar shape and horizontally placed, a member having an U-shaped cross section and being horizontally placed so that the upper surface is open, or a member having a convex cross section and being inserted into the cavity part of the support post.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a seismic isolation structure for storage shelves. Structure It relates thereto.

Background Art

[0002] In recent years, there has been an increasing movement to consider and introduce disaster reduction measures such as seismic isolation and vibration control for buildings. Also, for equipment and facilities, development of earthquake countermeasure technologies has been promoted for the purpose of disaster reduction measures so that economic activities do not fall into dysfunction. However, many of the earthquake countermeasure technologies target high-performance and high-price equipment and facilities, and generally have high costs. Also, seismic isolation of buildings requires renovation work on the building's foundation, and it is difficult to adopt for existing facilities in use. In logistics facilities, in movable storage shelves frequently used for storing goods (for example, nesting racks and storage shelves used in an automatic conveyance system [floor conveyance robot, low-floor unmanned conveyance vehicle] that automatically conveys to a loading and unloading location by diving under the storage shelf), load drop countermeasures (for example, stretch wrapping, fall prevention stoppers, pallet anti-slip rubber, etc.) are implemented as needed. However, when the storage shelf encounters a strong earthquake with a seismic intensity of 5 or higher, there is a risk of earthquake damage where the stacked goods fall. Also, these storage shelves generally have a large aspect ratio (height-width ratio) to improve the storage efficiency of goods. Therefore, when the input acceleration of the earthquake increases, a phenomenon occurs where one side of the column base is lifted along with the rocking vibration, and there is a risk of earthquake damage such as the storage shelf tipping over or being damaged. Therefore, there is a need for a seismic isolation system applicable to existing facilities in logistics facilities that can reduce earthquake damage and achieve early restoration after an earthquake. For example, Patent Document 1 discloses a method for seismic isolation of a rack in which a new beam is horizontally installed at the lower part of a column for an existing rack, a seismic isolation device is installed between the new beam and the floor surface, and then the column is cut between the new beam and the floor surface. On the one hand, there are logistics facilities that can freely set the layout and the number of shelves by using these movable storage shelves. In such logistics facilities, it is necessary to maintain the standard form of the movable storage shelves, and processing such as cutting the legs of the columns cannot be performed as in the seismic isolation method of Patent Document 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention aims to propose a seismic isolation structure for a storage shelf that can reduce earthquake damage by a simple mechanism for a movable storage shelf. Structure as an issue.

Means for Solving the Problems

[0005] The present invention for solving the above problems is a seismic isolation structure for a storage shelf in which a cast iron bearing is interposed between the column foot of the column of the storage shelf and the concrete floor surface. The bearing has a coefficient of kinetic friction with respect to concrete of 0.3 or less, preferably 0.15 to 0.25, and when a horizontal force equal to or greater than a predetermined value acts during an earthquake, the storage shelf slides on the concrete floor surface. It is desirable that the bearing supports the column rotatably about an axis parallel to the concrete floor surface. The bearing used in such a seismic isolation structure of a storage shelf is It has a triangular cross-section formed by a rectangular lower surface and a pair of inclined surfaces extending upward from two opposite sides of the lower surface. Alternatively, It has a U-shaped cross-section formed by a rectangular base plate and a pair of opposite side plates rising from two opposite sides of the base plate with an interval into which the lower end of the column base can be inserted. . A U-shaped cross-section bearing is installed on the column foot of the column so as to cover the lower end surface of the column foot and the lower ends of the two opposing side surfaces. Further, when a groove having a triangular cross-section is formed in the column foot, a bearing having a substantially triangular prism outer shape is inserted into the groove. structure . In addition, when the column is composed of a cylindrical member, at least a part of the support is inserted into the cavity of the column. structure .

[0006] In the seismic isolation structure of such a storage shelf, since a cast iron support is provided between the column base and the concrete floor surface, it is possible to reduce the friction coefficient with the concrete floor surface. The cast iron support can reduce the friction coefficient with the concrete floor surface compared to steel due to the lubricating action of graphite contained in the cast iron. Therefore, even when a lateral force acts during an earthquake, the column base (support) slides on the concrete floor surface, suppressing the response of the storage shelf and thus reducing the fall of the load. In addition, when the storage shelf slides with respect to the seismic motion, the force during the earthquake can be absorbed, suppressing the overturning and damage of the storage shelf. Further, when the support rotatably supports the storage shelf, it is possible to prevent the column base from separating from the floor surface due to rocking vibration and slide the storage shelf while maintaining the posture of the storage shelf during an earthquake.

Advantages of the Invention

[0007] According to the seismic isolation structure of the storage shelf of the present invention, it is possible to reduce the earthquake damage of the movable storage shelf by a simple mechanism. Structure

Brief Description of the Drawings

[0008]

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Mode for Carrying Out the Invention

[0009] <First Embodiment> In this embodiment, a seismic isolation structure (seismic isolation structure 1) of a storage shelf is described for a movable storage shelf (among them, a positive nesting rack: a type with a loading part at the lower part) 2 used in a logistics warehouse, aiming to suppress earthquake damage such as the fall of loads from the storage shelf 2, the overturning of the storage shelf 2, and damage even when encountering a strong earthquake of seismic intensity 5 or higher. The seismic isolation structure 1 of the first embodiment interposes a support 3 between the column foot part 23 of the column 22 of the storage shelf 2 and the concrete floor surface 4. FIG. 1 is a perspective view showing the storage shelf 2 of this embodiment.

[0010] As shown in Fig. 1, the storage shed 2 includes a grid-shaped loading portion 21 and columns 22 to which the loading portion 21 is fixed. Fig. 2 is a view showing the storage shed 2, where (a) is a plan view, (b) is a cross-sectional view of the leg horizontal member 24, (c) is a front view, and (d) is a side view. As shown in Fig. 2(a), the loading portion 21 is formed in a grid shape by combining metal members. The loading portion 21 can also be constituted by a plate material having a rectangular shape in plan view. The columns 22 are respectively disposed at the four corners of the loading portion 21. The columns 22 are made of metal square tubes, and the loading portion 21 is fixed to the side surface at a position above the lower end (the lower tip), that is, at a predetermined interval from the lower end. That is, a gap is secured between the loading portion 21 and the concrete floor surface 4. As shown in Fig. 2(d), a leg horizontal member 24 that connects the columns 22 arranged front and back is fixed to the column feet portion 23 of the column 22. As shown in Fig. 2(b), the leg horizontal member 24 is made of a metal member having a triangular cross section. The inner angle of the leg horizontal member 24 is 90°. That is, the leg horizontal member 24 forms a groove having a triangular cross section with the concrete floor surface 4 side open. As shown in Fig. 2(c), in this embodiment, a support plate 25 is fixed to the corner portion between the loading portion 21 and the column 22. The leg horizontal member 24 is fixed to the column feet portion 23 by the support plate 25. Triangular notches are formed in the support plate 25 according to the position of the leg horizontal member 24. The leg horizontal member 24 is fixed in a state of being fitted into the notches of the support plate 25. Also, as shown in Fig. 2(d), an upper horizontal member 26 that connects the front and rear columns 22 is provided at the upper end portion of the column 22. The upper horizontal member 26 is made of an angle member having a triangular cross section that meshes with the leg horizontal member 24. The upper horizontal member 26 is provided so as to overlap with the leg horizontal member 24 in plan view, and when another storage shed 2 is stacked on the storage shed 2, it is inserted into the leg horizontal member 24 of the other storage shed 2. The front portion of the upper horizontal member 26 is supported by a receiving member 28 that projects from the side surfaces of the left and right columns 22, 22 arranged at the front portion of the storage shed 2, as shown in Fig. 2(c). Also, the rear portion of the upper horizontal member 26 is supported by a receiving girder 27 that is horizontally mounted on the left and right columns 22, 22 arranged at the rear portion of the storage shed 2, as shown in Fig. 1.

[0011] The support 3 is made of a cast iron member with a coefficient of kinetic friction against concrete placed on the concrete floor surface 4 of 0.3 or less, preferably 0.15 to 0.25 (see FIGS. 1 and 2(c)). FIG. 3 is a perspective view showing the support 3. As shown in FIG. 3, the support 3 has a rectangular lower surface 31 that abuts against the concrete floor surface 4 and a pair of inclined surfaces 32, 32 that extend upward from two opposite sides of the lower surface 31, presenting a triangular cross-sectional shape. That is, the support 3 of the present embodiment is configured by horizontally placing a triangular prism-shaped cast iron member. Holes 33 with a predetermined depth (18 mm in this embodiment) are formed in at least one of the inclined surfaces 32 of the support 3. Fixtures such as bolts and pins are attached to the holes 33. The angles of the corners of both inclined surfaces 32 of the support 3 (the apex angle of the support 3) are smaller than the inner angle of the leg horizontal member 24 (90° in this embodiment). In this embodiment, the angle of the upper end portion of the support 3 is 80°.

[0012] As shown in FIG. 4, the support 3 is inserted into the leg horizontal member 24 at the column leg portion 23 (below the column 22). FIG. 4 is an enlarged cross-sectional view showing the support 3 and the leg horizontal member 24. The support 3 is attached to the leg horizontal member 24 by inserting a fixture 5 that has penetrated one piece of the leg horizontal member 24 into the hole 33. A through hole 29 for inserting the fixture 5 is formed in the leg horizontal member 24. The inner diameter of the through hole 29 is larger than the outer diameter of the shaft portion of the fixture 5 and smaller than the outer diameter of the head portion of the fixture 5. When the fixture 5 is inserted through the through hole 29, a gap is formed between the outer surface of the shaft portion of the fixture 5 and the inner wall surface of the through hole 29.

[0013] According to the seismic isolation structure 1 of this embodiment, since the bearing 3 interposed between the column base portion 23 and the concrete floor surface 4 is made of cast iron, it is possible to reduce the friction coefficient with the concrete floor surface 4. The cast iron bearing 3 can reduce the dynamic friction coefficient with the concrete floor surface 4 to 0.3 or less compared to steel due to the lubricating action of graphite contained in the cast iron. When the cast iron bearing 3 wears due to sliding, wear powder containing a large amount of graphite is generated. And this wear powder functions as a lubricant by forming a film on the sliding surface. Therefore, even when a horizontal force equal to or greater than a predetermined value acts on the storage shelf 2 during an earthquake, the column base portion 23 (bearing 3) slides on the concrete floor surface 4, suppressing the response of the storage shelf 2 and thus preventing the load from falling. Also, due to the sliding of the storage shelf 2 against seismic motion, the force during an earthquake can be absorbed and the overturning of the storage shelf 2 can be suppressed. Further, since the angle of the apex angle of the bearing 3 is smaller than the inner angle of the leg horizontal member 24, it is possible to support the bearing 3 rotatably about its axis (an axis parallel to the concrete floor surface 4). Also, since the through hole 29 through which the fixture 5 formed in the leg horizontal member 24 is inserted has an inner diameter larger than the diameter of the shaft portion of the fixture 5, the bearing 3 is also rotatable about an axis orthogonal to the axis of the bearing 3. Thus, since the bearing 3 supports the storage shelf 2 rotatably, it is possible to prevent the column base portion 23 from separating from the concrete floor surface 4 due to rocking vibration and to slide the storage shelf 2 while maintaining the posture of the storage shelf 2 during an earthquake.

[0014] Here, FIGS. 5 and 6 show a modified example of the bearing 3. The bearing 3 is not limited to a solid member and may be a hollow member as shown in FIG. 5. Also, as shown in FIG. 6, the bearing 3 may be partially formed with recesses (grooves) 34. The recesses 34 of the bearing 3 are provided at both ends of the bearing 3 and at portions other than the locations where the holes 33 are formed. At this time, the lower surface 31 of the bearing 3 is rectangular to ensure a predetermined area. The depth, arrangement, number, etc. of the recesses 34 are not limited and are determined as appropriate.

[0015] <Second Embodiment> In the second embodiment, similar to the first embodiment, for the movable storage shelf (the storage shelf used in an automatic conveyance system [floor conveyance robot, low-floor unmanned conveyance vehicle] that automatically conveys to the loading and unloading location by diving under the lower part of the storage shelf) 2 used in a logistics warehouse, even when encountering a strong earthquake with a seismic intensity of 5 or higher, a seismic isolation structure 11 aimed at suppressing earthquake damage such as the fall of loads from the storage shelf 2, the overturning of the storage shelf 2, and damage will be described. The seismic isolation structure 11 of the embodiment is configured such that a bearing 6 is interposed between the column base portion 23 of the column 22 of the storage shelf 2 and the concrete floor surface 4. FIG. 7 is a perspective view showing the storage shelf 2 of the second embodiment.

[0016] As shown in FIG. 7, the storage shelf 2 includes a rectangular load placement portion 21 and columns 22 that support the load placement portion 21. The load placement portion 21 is made of a rectangular metal plate in plan view and is supported by the columns 22 at the four corners. In this embodiment, four stages of load placement portions 21 are provided at equal intervals vertically, but the number of stages of the load placement portions 21 and the intervals between the load placement portions 21 are not limited. The column 22 is made of a metal member having a U-shaped cross section. At the lower end of the column 22 of this embodiment, a leg member 23a (see FIG. 8(a)) having a bottom area larger than the cross section of the column 22 is provided. A part of the leg member 23a projects from the side surface of the column 22. An attachment plate 23b that abuts against the inner surface of the column base portion 23 of the column 22 is erected on the leg member 23a. Bolt holes 23c are formed in the attachment plate 23b at positions corresponding to the positions of through holes 29 formed in the column base portion 23. The lower end (column base portion 23 and leg member 23a) of the column 22 is inserted into the bearing 6.

[0017] FIG. 8 shows the support 6, where (a) is a plan view, (b) is a longitudinal sectional view, and (c) is a cross-sectional view. The support 6 is made of a cast iron member having a coefficient of kinetic friction against concrete placed on the concrete floor surface 4 of 0.3 or less, preferably 0.15 to 0.25 (see FIGS. 8(b) and (c)). As shown in FIGS. 8(a) to (c), the support 6 has a rectangular bottom plate 61 that abuts against the concrete floor surface 4 and a pair of opposing side plates 62, 62 that rise from two opposing sides of the bottom plate 61, presenting a U-shaped (concave-shaped) cross-section. That is, the support 6 is a columnar member with a U-shaped cross-section placed horizontally with its upper surface open. As shown in FIG. 8(c), the support 6 covers the lower end surface of the support column 22 (column foot portion 23) and the lower ends of the two opposing side surfaces with the bottom plate 61 and the pair of side plates 62, 62. The four supports 6 are arranged in the same direction, and the side plate 62 of one support 6 is parallel to the side plate 62 of the other support 6. A through-hole 63 is formed in the side plate 62. A fixture 5 such as a bolt or a pin is attached to the through-hole 63.

[0018] The support 6 is attached to the column foot portion 23 (support column 22) by screwing a fixture 5 that passes through the through-hole 63 in the side plate 62 and the through-hole 29 formed in the column foot portion 23 into the bolt hole 23c. At this time, the leg member 23a of the support column 22 is in a state of being placed on the upper surface of the bottom plate 61. The fixture 5 is installed so that its central axis is horizontal. Also, the through-hole 29 is larger than the outer diameter of the shaft portion of the fixture 5. Therefore, when the fixture 5 is inserted through the through-hole 29, a gap is formed between the outer surface of the shaft portion of the fixture 5 and the through-hole 29. The central axis of the fixture 5 arranged on one support 6 is parallel to the central axis of the fixture 5 arranged on the other support 6.

[0019] According to the seismic isolation structure 11 of the second embodiment, the same operational effects as those of the seismic isolation structure 1 of the first embodiment can be obtained. Here, a modified example of the support 6 is shown in FIG. 9. The support 6 is not limited to a member that covers only two surfaces facing the bottom surface of the column base portion 23, and may surround the entire circumference of the column base portion 23. That is, the support 6 may include a rectangular bottom plate 61 and rectangular tube-shaped side plates 62 extending upward from each side of the bottom plate 61.

[0020] <Third Embodiment> In the third embodiment, similar to the first embodiment, for a movable storage shelf (a storage shelf used in an automatic conveyance system [floor conveyance robot, low-floor unmanned conveyance vehicle] that automatically conveys to a loading / unloading location by diving under the lower part of the storage shelf) 2 used in a logistics warehouse, even when encountering a strong earthquake with a seismic intensity of 5 or higher, a seismic isolation structure 12 aimed at suppressing seismic damage such as the fall of loads from the storage shelf 2, the overturning of the storage shelf 2, and damage will be described. The seismic isolation structure 12 of the embodiment has a support 8 interposed between the column base portion 23 of the column 22 of the storage shelf 2 and the concrete floor surface 4. FIG. 10 is a perspective view showing the storage shelf 2 of the third embodiment.

[0021] As shown in FIG. 10, the storage shelf 2 includes a rectangular load placement portion 21 and columns 22 that support the load placement portion 21. The load placement portion 21 is made of a metal plate having a rectangular shape in plan view and is supported by the columns 22 at the four corners. In this embodiment, four stages of load placement portions 21 are provided at equal intervals vertically, but the number of stages of the load placement portions 21 and the intervals between the load placement portions 21 are not limited. The column 22 is made of a hollow rectangular tube-shaped (tubular) metal member. The lower end of the column 22 of this embodiment is open, and a part (upper part) of the support 8 is inserted therein.

[0022] Fig. 11 shows the support 8, where (a) is a plan view and (b) is a sectional view. The support 8 is made of a cast iron member with a coefficient of kinetic friction against the concrete placed on the concrete floor surface 4 of 0.3 or less, preferably 0.15 - 0.25. As shown in Figs. 11(a) and (b), the support 8 is composed of a rectangular bottom plate portion 81 that abuts against the concrete floor surface 4 and a prismatic fitting portion 82 that is fitted into the hollow portion of the support column 22 (column base portion 23). The bottom plate portion 81 and the fitting portion 82 are integrally formed. The fitting portion 82 has a cross-sectional shape smaller than that of the hollow portion of the support column 22. On the other hand, the bottom plate portion 81 has an outer shape larger than that of the support column 22, and in sectional view, both ends of the bottom plate portion 81 protrude from the side surfaces of the fitting portion 82. That is, the support 8 is convex-shaped in sectional view. A through-hole 83 is formed in the fitting portion 82. A fixture 5 such as a bolt is attached to the through-hole 83. By using the hole for installing the shelf board, the support 8 can be installed without drilling a hole in the column base portion 23. The support 8 is attached to the column base portion 23 by screwing a nut 51 onto the fixture 5 that passes through the through-hole 83 of the fitting portion 82 and the through-hole 29 formed in the column base portion 23. The support 8 can be made by individually creating a support mounting fitting with the bottom plate portion 81 made of cast iron and the fitting portion 82 made of steel, and joining them together with a dish bolt or the like to make them integral.

[0023] According to the seismic isolation structure 12 of the third embodiment, since the support 8 provided between the column base portion 23 and the concrete floor surface 4 is made of cast iron, the lubricating action of the graphite contained in the cast iron can reduce the coefficient of friction with the concrete floor surface 4. Therefore, even when a horizontal force above a predetermined value acts during an earthquake, the column base portion 23 (support 8) can slide on the concrete floor surface 4, suppressing the response of the storage shelf 2 and thus preventing the load from falling. Also, when the storage shelf 2 slides with respect to the seismic motion, the force during the earthquake can be absorbed, suppressing the overturning of the storage shelf 2.

[0024] Here, a modified example of the support 8 is shown in FIG. 12. As shown in FIGS. 12(a) and (b), the support 8 may form a gap between the side surface of the fitting portion 82 and the inner surface of the support column 22 by providing a taper 83 on the fitting portion 82 or the like. By doing so, the support 8 can also rotate about the axis of the fixture 5, preventing the column leg portion 23 of the support column 22 from separating from the concrete floor surface 4 due to rocking vibration, and enabling the storage shelf 2 to slide while maintaining the posture of the storage shelf 2 during an earthquake. Further, when the support column 22 is cylindrical, the fitting portion 82 may be formed in a cylindrical shape, and the cross-sectional shape of the fitting portion 82 is not limited.

[0025] Next, the results of the shaking table experiment conducted on the seismic isolation structure 1 of the first embodiment are shown. FIG. 13 shows a test body diagram of the shaking table experiment. The test body 10 was constructed by installing and stacking two storage shelves 2 on the concrete slab 41. A load placement portion 21 was formed at the upper end portion of the support column 22 on the upper storage shelf 2. That is, the test body 10 had three load placement portions 21. A weight 71 was placed on the lowermost load placement portion 21, and on the second stage (middle stage) and third stage (uppermost stage) load placement portions 21, 21, 10 cardboard boxes 73 stacked on a plastic pallet 72 were placed respectively. Here, the mass of the weight 71 was made the same as the total value of the total mass of the cardboard boxes 73 and the mass of the plastic pallet 72. As a comparative example, the same experiment was also conducted for the case without countermeasures where the support 3 was not provided. FIG. 14(a) shows the relationship between the input acceleration and time of the comparative example, (b) shows the relationship between the response acceleration and time at the third stage (uppermost stage) load placement portion 21 of the comparative example, FIG. 14(c) shows the relationship between the input acceleration and time of the example, and (d) shows the relationship between the response acceleration and time at the third stage (uppermost stage) load placement portion 21 of the example.

[0026] As shown in FIGS. 14(a) and (c), in both the comparative example and the example, the maximum value of the input acceleration was about 400 cm / s 2 On the other hand, as shown in FIG. 14(b), in the comparative example, the maximum value of the response acceleration at the uppermost load placement portion 21 was 2300 cm / s 2whereas in the Example, as shown in Fig. 14(d), the maximum value of the response acceleration at the uppermost load placement part 21 was 1500 cm / s 2 or so. Therefore, by adopting the seismic isolation structure 1, the response acceleration was significantly reduced (by about 35% compared with the Comparative Example). Also, in the Comparative Example, the cardboard (loaded goods) fell, whereas in the Example, the loaded goods did not fall. From the above results, according to the seismic isolation structure 1 of the present invention, seismic damage to the storage shelf can be reduced.

[0027] As described above, the embodiments according to the present invention have been explained. However, the present invention is not limited to the foregoing embodiments, and each of the above-described components can be appropriately changed without departing from the gist of the present invention. The seismic isolation structure of the present invention can be used, for example, for the column bases of movable storage shelves such as reverse nesting racks (type with load placement part at the upper part) or stationary storage shelves (pallet racks [weight shelves], single-item shelves [medium-capacity shelves], etc.), or for the rack column bases of bucket automated warehouses. Also, the material constituting the storage shelf 2 is not limited, and may be, for example, steel, stainless steel, aluminum alloy, or wooden materials.

Explanation of Reference Numerals

[0028] 1, 11, 12 Seismic isolation structure (seismic isolation structure of storage shelf) 2 Storage shelf 21 Load placement part 22 Support column 23 Column base 24 Foot horizontal member 25 Support plate 26 Upper horizontal member 27 Receiving girder 28 Receiving member 29 Through hole 3 Support 31 Lower surface 32 Inclined surface 33 Hole 4 Concrete floor surface 5 Fastener 6 Support 61 Bottom plate 62 Side plate 63 Through hole 8 Supports 81 Bottom Plate Portion 82 Fitting Portion

Claims

1. A seismic isolation structure for a storage shelf, wherein a cast iron support is interposed between the column base of the support column of the storage shelf and the concrete floor surface, the support supports the column rotatably about an axis parallel to the concrete floor surface, has a coefficient of kinetic friction with respect to concrete of 0.3 or less, and when a horizontal force equal to or greater than a predetermined value acts during an earthquake, the storage shelf slides on the concrete floor surface. A seismic isolation structure for a storage shelf, characterized in that.

2. A seismic isolation structure for a storage shelf, wherein a cast iron support is interposed between the column base of the support column of the storage shelf and the concrete floor surface, a groove having a triangular cross section is formed in the column base, the support has a triangular cross section formed by a rectangular lower surface in contact with the concrete floor surface and a pair of inclined surfaces extending upward from two opposite sides of the lower surface, is inserted into the groove, and has a coefficient of kinetic friction with respect to concrete of 0.3 or less. A seismic isolation structure for a storage shelf, characterized in that when a horizontal force equal to or greater than a predetermined value acts during an earthquake, the storage shelf slides on the concrete floor surface.

3. A seismic isolation structure for a storage shelf, wherein a cast iron support is interposed between the column base of the support column of the storage shelf and the concrete floor surface, the support has a U-shaped cross section having a bottom plate in contact with the concrete floor surface and a pair of opposing side plates, covers the lower end surface of the column base and the lower ends of the two opposing side surfaces, and has a coefficient of kinetic friction with respect to concrete of 0.3 or less. A seismic isolation structure for a storage shelf, characterized in that when a horizontal force equal to or greater than a predetermined value acts during an earthquake, the storage shelf slides on the concrete floor surface.

4. A seismic isolation structure for a storage shelf, wherein a cast iron support is interposed between the column base of the support column of the storage shelf and the concrete floor surface, the support has a coefficient of kinetic friction with respect to concrete of 0.3 or less, and when a horizontal force equal to or greater than a predetermined value acts during an earthquake, the storage shelf slides on the concrete floor surface, the column is composed of a cylindrical member, A seismic isolation structure for a storage shelf, characterized in that at least a part of the support is inserted into the cavity of the column.

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