JP2011001756A - Base-isolated structure under foundation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base-isolated structure under a foundation, which applies base isolation to a building by causing a slip under the foundation during earthquakes, and which can effectively restrain the building from making a rotational motion during the earthquakes.SOLUTION: The concrete foundation 1 of the building is supported on ground 2 via a foamed resin plate 4; upper and lower slip sheets 5 and 5 put into the state of overlapping each other are interposed between the foamed resin plate 4 and the concrete foundation 1; and horizontal shaking caused by the earthquakes brings about the slip between the upper and lower slip sheets 5 and 5 of the base isolation, so as to apply the base isolation to the building.

Description

  The present invention relates to a base-isolated structure.

  A leveling layer made of concrete or mortar is formed on the ground, and a concrete foundation is supported on the leveling layer via a vinyl chloride sheet. Between the vinyl chloride sheet and the leveling layer due to rolling due to an earthquake, A base-isolated base structure has been proposed in which a building slips and the building is isolated from the base.

Japanese Patent Laid-Open No. 11-141183

  However, since both the leveling layer and the concrete foundation are hard, if the load-bearing wall of the building is subjected to a horizontal force due to the rolling due to the earthquake, the surface between the leveling layer and the concrete foundation in the force transmission process. There is a problem that the pressure varies, which causes a variation in resistance on the sliding surface, causing a rotational movement in the building and increasing the response displacement.

  In view of the above-described problems, the present invention effectively suppresses the rotational movement of a building during base isolation in a base-isolated structure that causes the building to slip by causing a slip beneath the base during an earthquake. It is an object to provide a seismic isolation structure under the foundation.

  The above problem is that the concrete foundation of the building is supported on the ground via the foamed resin plate, and the upper and lower sliding sheets in an overlapped state are interposed between the foamed resin plate and the concrete foundation, The problem is solved by a base-isolated structure, which is characterized in that the building is isolated from the base by sliding between the upper and lower sliding seats due to the rolling due to the earthquake.

  In this structure, when the building's load-bearing wall receives a horizontal force due to the rolling due to an earthquake, the surface pressure between the foamed resin plate and the concrete foundation is reduced by the spring action in the vertical direction of the foamed resin plate in the force transmission process. The variation is alleviated, the resistance force on the sliding surface between the upper and lower sliding sheets is made constant, and it is possible to effectively suppress the building from rotating during seismic isolation.

  Moreover, between the foamed resin plate and the concrete foundation, the upper and lower sliding sheets in an overlapped state are interposed, so that the building is made to squeeze by causing the sliding between the upper and lower sliding sheets, Smooth sliding can be realized, and the foamed resin plate can be prevented from being damaged by the concrete foundation.

  In addition, by adopting the foamed resin plate as described above, the vertical vibration caused by an earthquake or environmental vibration can be mitigated by the spring action in the vertical direction of the foamed resin plate.

  Since the present invention is as described above, in a base-isolated structure that causes the building to slip by causing a slip beneath the base during an earthquake, it effectively suppresses the rotational movement of the building during base isolation. be able to. In addition, the foamed resin plate is not damaged by the concrete foundation during the seismic isolation, and the pitching caused by the earthquake or environmental vibration can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional side view and FIG. (B) is an enlarged exploded side view of a part A in FIG. FIGS. 1A and 1B are cross-sectional front views showing a test body and a test apparatus for effect confirmation, and FIGS. 3C and 4D are graphs showing the results.

  Next, embodiments of the present invention will be described with reference to the drawings.

  In the base-isolated structure of the embodiment shown in FIG. 1, 1 is a concrete foundation of a building, 2 is the ground, and the ground 2 is provided with a leveling layer 3 made of gravel and crushed stone. The concrete foundation 1 is supported on the upper and lower sides of a foamed resin plate 4 made of foamed polypropylene, polystyrene foam, or the like. Sliding sheets 5 and 5 are interposed so that the building is quake-free due to slippage between the upper and lower sliding sheets 5 and 5 due to rolling due to the earthquake.

  The sliding sheets 5 and 5 are made of, for example, a fluororesin sheet, and the sliding sheets 5 and 5 are protected from moisture or the like on the upper surface side of the upper sliding sheet 5 and the lower surface side of the lower sliding sheet 5, respectively. Protective sheets 6 and 6 are provided as necessary.

  The thickness dimension of the foamed resin plate 4 is, for example, 50 mm, the total thickness dimension of the sheets 5, 5, 6, 6 is, for example, about 6 mm, and the thickness dimension of the footing portion of the concrete foundation 1 is, for example, 155 mm. It is.

  In the above base-isolated structure, when the bearing wall of the building receives a horizontal force due to the rolling due to the earthquake, the foamed resin plate 4 and the concrete foundation are caused by the spring action in the vertical direction of the foamed resin plate 4 in the force transmission process. 1 is alleviated, the resistance force on the sliding surface between the upper and lower sliding sheets 5 and 5 is made constant, and the building is effectively prevented from rotating during seismic isolation. be able to.

  In addition, the upper and lower sliding sheets 5 and 5 placed between the foamed resin plate 4 and the concrete foundation 1 are interposed, and the building is isolated by causing slippage between the upper and lower sliding sheets 5 and 5. Thus, smooth sliding can be realized, and the foamed resin plate 4 can be prevented from being damaged by the concrete foundation 1.

  In addition, by adopting the foamed resin plate 4 as described above, the vertical vibration caused by environmental vibrations such as earthquakes and traffic vibrations can be mitigated by the spring action of the foamed resin plate 4 in the vertical direction.

  Moreover, in this embodiment, since the leveling layer 3 consists of gravel and crushed stone, it can implement | achieve cost reduction and shortening of a construction period. The leveling layer 3 may be made of discarded concrete.

By the way,
As shown in FIG. 2 (a), the weight 12 is placed horizontally by the actuator 13 on a hard surface plate 10 on which a weight 12 is placed via a fluororesin-based sliding sheet 11 (test body A). The friction coefficient when reciprocating in the direction is measured by varying the weight of the weight 12, and
As shown in FIG. 2 (b), a weight 12 is placed on a hard surface plate 10 via a foamed resin plate 14 made of foamed polypropylene, and a fluororesin system is interposed between the weight 12 and the foamed resin plate 14. The friction coefficient when the weight 12 was reciprocated in the horizontal direction by the actuator 13 was measured with the weight of the weight 12 being varied. (C) The results shown in (d) were obtained.

2A and 2B, 15 is a load measuring device, 16 and 17 are displacement measuring meters, and 18 is an acceleration measuring device. 2 (C) and 2 (D), P is 9.64 kN / m ² .

  From the results shown in FIGS. 2 (a) and 2 (d), the average value of the friction coefficient is 0.137 and the variation of the friction coefficient is −35% to + 39% in the test body A, and the friction coefficient of the test body B is The average value is 0.2, the variation in the friction coefficient is -7% to + 8%, and the variation in the friction coefficient due to the difference in the surface pressure is reduced by using the foamed resin plate 14 as in the specimen B. I was able to confirm.

DESCRIPTION OF SYMBOLS 1 ... Concrete foundation 2 ... Ground 4 ... Foamed resin board 5 ... Sliding sheet

Claims (1)

  The concrete foundation of the building is supported on the ground via a foamed resin board, and upper and lower sliding sheets are placed between the foamed resin board and the concrete foundation, A seismic isolation structure under the foundation, characterized in that the building is seismically isolated by sliding between the upper and lower sliding seats.

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