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JP-7856523-B2 - Seismic isolation mechanism

JP7856523B2JP 7856523 B2JP7856523 B2JP 7856523B2JP-7856523-B2

Inventors

  • 劉 銘崇

Assignees

  • 清水建設株式会社

Dates

Publication Date
20260511
Application Date
20220809

Claims (4)

  1. It is provided between a lower structure and an upper structure that are capable of relative displacement in the horizontal direction, A lower guide portion is provided on the lower structure and has a lower sliding surface formed on its upper surface in a V-shape that protrudes downward along the first horizontal direction, An upper guide portion provided below the superstructure, having an upper sliding surface formed on its lower surface in an inverted V shape that is convex upward along a second horizontal direction perpendicular to the first horizontal direction, The device comprises a slider positioned between the lower sliding surface and the upper sliding surface, which is displaceable relative to the lower guide portion in the first horizontal direction along the lower sliding surface, and displaceable relative to the upper guide portion in the second horizontal direction along the upper sliding surface, The aforementioned slider is, A lower sliding part provided at the lower part and capable of sliding on the lower sliding surface, An upper sliding part provided at the top and capable of sliding on the upper sliding surface, A laminated rubber portion is provided between the lower sliding portion and the upper sliding portion and supports the lower sliding portion and the upper sliding portion so that they can move relative to each other in the horizontal direction. A lower shear force transmission section that transmits shear force from the lower sliding section to the laminated rubber section, It has an upper shear force transmission section that transmits shear force from the upper sliding section to the laminated rubber section, The laminated rubber portion is Laminated rubber body, A lower joining member is joined to the lower surface of the laminated rubber body and is capable of transmitting shear force to the laminated rubber body, The laminated rubber body has an upper joining member that is joined to the upper surface of the laminated rubber body and is capable of transmitting shear force to the laminated rubber body, The lower shear force transmission section is disc-shaped with its axis in the vertical direction, and is positioned between the lower sliding section and the lower joining member, transmitting shear force between the lower sliding section and the lower joining member via its outer circumferential surface. The upper shear force transmission section is disc-shaped with its axis in the vertical direction, and is positioned between the upper sliding section and the upper joining member. This seismic isolation mechanism transmits shear force between the upper sliding section and the upper joining member via its outer circumferential surface.
  2. The lower shear force transmission section is inserted into a circular hole formed in the lower sliding section at its lower end, and into a circular hole formed in the lower joining member at its upper end. The seismic isolation mechanism according to claim 1, wherein the upper shear force transmission portion is inserted into a circular hole formed in the upper sliding portion at its upper end and into a circular hole formed in the upper joining member at its lower end.
  3. The seismic isolation mechanism according to claim 1 or 2, wherein the maximum deformation of the laminated rubber body is 2.5 times or less the thickness of the rubber layer of the laminated rubber body.
  4. The coefficient of friction between the slider and the lower sliding surface, and the coefficient of friction between the slider and the upper sliding surface, are 0.15 or less. The seismic isolation mechanism according to claim 1 or 2 , wherein the shear modulus of the laminated rubber body is 0.4 N/ mm² or more and 0.8 N/mm² or less.

Description

This invention relates to a seismic isolation mechanism. The Great East Japan Earthquake caused extensive damage to logistics facilities such as rack warehouses. It was found that the damage was more due to the collapse and falling of goods stored in the rack structures than to damage to the rack structures themselves, which consist of multiple layers of racks. The conditions for cargo collapse and falling depend on whether the acceleration of the pallets storing the goods exceeds approximately 500 cm/ s² (hereinafter referred to as cargo sliding acceleration). In particular, high-rise automated rack warehouses with a height of 15m or more are prone to amplified acceleration due to earthquakes because they are independent structures with a high aspect ratio (ratio of the length in the height direction to the width direction of the structure). As a result, the cargo sliding acceleration near the top of the racks can significantly exceed 500 cm/ s² . In order to prevent cargo collapse and falling, it is important to reduce the acceleration near the top of the racks in automated rack warehouses. Patent Document 1 discloses a vibration damping structure in which TMDs (Tuned Mass Dampers) are installed on the racks as a structure to reduce acceleration in automated rack warehouses. Non-Patent Document 1 discloses a vibration damping structure in which mass dampers are installed on the racks. Such vibration damping structures are effective against seismic waves with predominantly long-period components, but in the case of seismic waves with predominantly short-period components such as pulses, tuned TMDs may not be very effective. Furthermore, they are insufficient to suppress the load sliding acceleration at the top of the automated rack warehouse to 500 cm/ s² or less, so a separate seismic isolation system is required. Patent Document 2 discloses a seismic isolation mechanism that uses rolling bearings, viscous dampers, and horizontal springs between the rack installation section and the warehouse floor. Such a seismic isolation mechanism, using a rigid horizontal spring in parallel with the rolling bearings, shortens the seismic period. Depending on the characteristics of the seismic waves, it may not be able to efficiently suppress the load sliding acceleration at the top of the automated rack warehouse, potentially resulting in insufficient seismic isolation. Furthermore, the device may be costly. Patent Document 3 discloses a vibration isolation and damping system that incorporates inclined sliding seismic isolation bearings and TMDs (Temperature Mass Diodes) into a rack. Such vibration isolation and damping systems, because they utilize TMDs, are only effective for racks where the weight and placement of the cargo do not fluctuate significantly (i.e., racks with a nearly constant structural period), and the equipment may occupy cargo storage space. Therefore, the applicant has proposed an inclined elastic sliding bearing that has the advantages of both inclined sliding bearings and laminated rubber as a seismic isolation mechanism to reduce the acceleration of structures (see Patent Document 4). The inclined elastic sliding bearing consists of a lower shoe, an upper shoe, and a slider provided between the lower shoe and the upper shoe. The slider consists of laminated rubber positioned in the center in the height direction, a lower sliding part provided below the laminated rubber, and an upper sliding part positioned above the laminated rubber. The outer periphery of the laminated rubber protrudes laterally beyond the sides of the lower sliding part and the upper sliding part, and is fixed to the lower sliding part and the upper sliding part with fasteners. The transmission of shear force between the lower sliding part and the upper sliding part and the laminated rubber occurs via the outer periphery of the laminated rubber. Patent Document 4 specifies a shear modulus G = 0.34 to 0.39 N/ mm² as a condition for adopting an inclined elastic sliding bearing in low-rise structures. Japanese Patent Publication No. 2014-141314Japanese Patent Publication No. 2016-056007Japanese Patent Publication No. 2018-131317Japanese Patent Publication No. 2019-138376 https://www.taisei.co.jp/giken/report/2013_46/paper/A046_032.pdf This figure shows an automated rack warehouse equipped with a seismic isolation mechanism according to an embodiment of the present invention.This is an overview of seismic isolation mechanisms.This is a view of the seismic isolation mechanism from above.This is a cross-sectional view taken along line A-A in Figure 3.This is a cross-sectional view taken along line B-B in Figure 3.This is an exploded perspective view of the slider.This is a perspective view of the slider.This diagram illustrates the restoration characteristics of the seismic isolation mechanism.This document includes a diagram illustrating the analytical model and a table showing the relationship between the height, mass, and stiffn