JP2009243486A - Laminated support - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated support 10 supporting a load with no rubber layer buckled even during large deformation without deteriorating the super high damping performance of a rubber layer 1. <P>SOLUTION: In this laminated support 10, the rubber material of the rubber layer 1 has a shearing distortion half amplitude γmax wherein G (γmax) becomes equal to G (100%) corresponding to a 100% shearing distortion half amplitude not existing in an area exceeding 100% or existing in an area exceeding 250% even if it exists, when the gradient of a straight line connecting a point corresponding to the distortion of +γmax in the shearing distortion-shearing stress of a curve in a third cycle when inputting such vibration that the shearing distortion half amplitude is set to γmax, to a point corresponding to the distortion of -γmax. Thicknesses Ta of rigid plates 11 positioned at one side or both ends in a height direction are thicker than thicknesses Tb of rigid plates 12 positioned closer to the center in the height direction than the rigid plates 11. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a laminated support for supporting a structure such as a building.

  In order to reduce the excitation force acting on a structure such as a building due to an earthquake or the like, this structure is supported by a laminated support body in which a rubber layer and a rigid plate are laminated. Is a cross-sectional view showing such a laminated support in a state in which it is greatly sheared and deformed by a horizontal excitation force, in which a reference numeral 91 denotes a rubber layer, a reference numeral 92 denotes a rigid plate, and Reference numeral 90 represents the entire laminate, and such a laminate support 90 supports a vertical load, and the excitation force is structured by the elastic force of the rubber layer 91 with respect to the excitation force in the horizontal direction. Although it functions to suppress transmission to an object, in addition to such a function, it is demanded to attenuate the vibration energy by converting it into heat by the damping characteristic of the rubber layer 91. As a rubber material used for the rubber layer 91 , Those having a very high damping characteristics have been developed (e.g., see Patent Document 1.)

  On the other hand, the laminated support 90 receives a horizontal excitation force and undergoes a large shear deformation as shown in FIG. 1, but also supports a large vertical load at the same time. When a load is applied, the point of action of the downward vertical load F is the center C of the upper flange, whereas the upward vertical load F as a reaction force is shifted horizontally from the point C of the lower flange. Since it acts on the center D, a large bending moment acts on each point of the laminated support 90, and the height distribution of this bending moment is zero at the center in the height direction as shown in FIG. Increasingly, it increases at both ends.

Therefore, a large bending moment acts on the rubber layer 91 located in the vicinity of both ends, and in such a state, if the elastic modulus of the rubber layer is low, the rubber layer 91 will buckle and cannot support the load. The rubber characteristics of the rubber layer 91 are required.
JP 2007-126560 A

  However, the rubber material having a high damping characteristic described above is mainly composed of a synthetic rubber having a small elongation crystallinity, and a large amount of resin filler is used to develop a high damping characteristic. There is a problem in that the damping characteristics cannot be improved if an attempt is made to configure the laminated support body so as not to buckle.

  The present invention has been made in view of such problems, and can support a load without buckling the rubber layer even during large deformation without impairing the ultrahigh damping performance of the rubber layer. An object of the present invention is to provide a laminated support that can be used.

The invention according to claim 1 is a laminated support formed by alternately laminating rubber layers and rigid plates.
The rubber material of the rubber layer has a point corresponding to the strain of + γmax in the shear strain-shear stress curve diagram in the third cycle when a vibration is input such that the amplitude of the shear strain piece is γmax, and the strain of −γmax. When the slope of the straight line connecting the points corresponding to is defined as the equivalent shear modulus G (γmax), G (γmax) is equal to G (100%) corresponding to the shear strain piece amplitude of 100%. The half amplitude γmax does not exist in the region exceeding 100%, or even if it exists, it exists in the region exceeding 250%,
The thickness Ta of the rigid plate located on one or both height direction end sides is larger than the thickness Tb of the rigid plate located on the center side in the height direction than these rigid plates. is there.

The invention described in claim 2 is the invention described in claim 1, wherein m is an integer obtained by dividing the total number of rigid plates by 5 (if the divided value is not an integer, the decimal part is rounded up). The number of rigid plates at the end in the height direction is 1 to m per side, and the thickness of these rigid plates satisfies the formula (1). is there.

1.3 ≦ Ta / Tb ≦ 3.0 (1)

  A third aspect of the present invention is the laminated support according to the first or second aspect, wherein the rigid plate is made of a steel plate.

  The invention according to claim 4 is the laminated support according to any one of claims 1 to 3, wherein the rigid plate has a diameter of less than 5.0 with respect to the total thickness of the rubber layer.

  According to the laminated support of claim 1, the rubber material of the rubber layer has a shear strain piece amplitude γmax in which G (γmax) is equal to G (100%) corresponding to a shear strain piece amplitude of 100%, It satisfies the requirement that it does not exist in the region exceeding 100%, or exists in the region exceeding 250% even if it exists, so it can maintain extremely high attenuation characteristics, and it is hardened in exchange for this characteristic. For the weakness of being low and easy to buckle, the rigid plate on the side close to both ends is made thicker so that the rigid plate yields near both ends where the shear stress is highest. Generation of buckling of the rubber layer can be prevented.

  According to the laminated support of claim 2, the number of rigid plates on one or both height direction ends is set to 1 to m per side, and the thickness of these rigid plates is Since the expression (1) is satisfied, buckling of the rubber layer can be more reliably prevented.

  According to the laminated support body of the third aspect, since the rigid plate is a steel plate, the elastic modulus of the rigid plate can be increased and the occurrence of buckling can be more effectively prevented.

  According to the laminated support of claim 4, since the cross-sectional shape of the rubber layer is such that the diameter of the rigid plate with respect to the total thickness is less than 5.0, buckling of the rubber layer can be further reliably suppressed. .

  The laminated support of the embodiment according to the present invention will be described below with reference to the drawings. FIG. 3 is a cross-sectional view showing the laminated support of this embodiment in a state where no horizontal excitation force is acting, and FIG. 4 is a diagram showing a case where the laminated support is shear-deformed by the excitation force. It is sectional drawing shown in a state, and the lamination | stacking support body 10 is comprised by laminating | stacking the rubber layer 1 and the rigid boards 11 and 12 alternately, and while absorbing the exciting force which acts on a lamination | stacking in-plane direction, it is height. It functions to support loads acting in the direction (vertical direction).

  3 and 4, reference numeral 4 is a flange for attaching the laminated support 10, and reference numeral 5 is a cover rubber layer for protecting the rubber layer 1 and the rigid plates 11 and 12 from the atmosphere. Reference numeral 6 represents a structure supported by the laminated support 10.

  The rubber layer 1 of the laminated support 10 of the present invention is one of the great features in that it can effectively attenuate the external excitation force. At the same time, the present invention has a weak point that the shear elastic modulus at the time of high shear deformation is not sufficiently high (low hardening), and this weak point is addressed by improving the structure of the laminated support 10. In this respect, the present invention is based on the premise that the rubber material of the rubber layer 1 does not have a sufficiently high shear modulus at the time of high shear deformation, and this is one of the requirements constituting the present invention. It is.

  This requirement is expressed quantitatively as follows. In other words, this requirement corresponds to the point corresponding to the strain of + γmax in the shear strain-shear stress curve diagram in the third cycle when the vibration having the shear strain piece amplitude of γmax is input and the strain of −γmax. When the slope of the straight line connecting the points to be used is the equivalent shear modulus G (γmax), G (γmax) is equal to G (100%) corresponding to 100% shear strain piece amplitude. γmax does not exist in the region exceeding 100%, or even if it exists, it exists in the region exceeding 250%, and will be described in detail below.

  FIG. 5 schematically shows a shear strain-shear stress curve diagram of such a rubber material. The horizontal axis represents the shear strain γ and the vertical axis represents the shear stress τ. When vibration is input so that the amplitude of the shear strain piece becomes γmax, the curve 21 is drawn in the first cycle, and the curve changes in the second cycle, the third cycle, and in the shear strain-shear stress curve diagram. The straight line L connecting the point P1 corresponding to the + γmax strain and the point P2 corresponding to the −γmax strain of the curve 22 in the third cycle is taken, and the gradient tanφ of the straight line L is called an equivalent shear modulus G (γmax). And For example, the equivalent shear elastic modulus when the maximum strain γmax is 100% can be expressed as G (100%).

  FIG. 6 is a graph showing the relationship between the shear strain piece amplitude γmax on the horizontal axis and G (γmax) / G (100%) on the vertical axis. This graph shows a large shear strain amplitude. For example, curve 1 shows whether G (γmax) decreases as γmax increases, but γmax recovers around 200%. First, G (γmax) becomes equal to G (100%) when γmax is around 300%.

  Curve 2 does not recover until G (γmax) monotonously decreases and becomes equal to G (100%) as γmax increases.

  On the other hand, in curve 3, G (γmax) decreases as γmax increases, but begins to recover when γmax exceeds 150%, and before γmax reaches 250%, G (γmax) becomes G (100 %).

  In the above three examples, the curve 3 shows that the shear strain amplitude γmax where G (γmax) is G (100%) exists in the region of 100 to 250%, and is equivalent in the high strain region exceeding 250%. Since the shear modulus is larger than G (100%), the above requirement is not satisfied. However, in Curve 1 and Curve 2, the shear strain piece amplitude γmax where G (γmax) is G (100%) is 100 to 250%. Therefore, the above requirement is satisfied. The rubber materials exemplified in Curve 1 and Curve 2 may buckle if the equivalent shear modulus G (γmax) is lower than G (100%) even in a high strain region exceeding 250%. Therefore, it is an aim of the present invention to prevent buckling by giving structural measures to the laminated support having such a rubber material.

  Here, 250% was set as the lower limit value of the shear strain amplitude, which prescribes the high strain region, and is generally 100% as an index for defining the linearity of the rubber material of the rubber layer in the laminated support. This is because the spring ratio at 250% strain with respect to the strain is used.

  Examples of the rubber material exhibiting the above characteristics include low-elasticity rubber materials such as natural rubber-based laminated rubber having G (100%) of 0.4 MP.

Next, the second requirement that constitutes the present invention is a method for overcoming the problem that such a rubber material having excellent damping characteristics has low hardening, and this is one of the requirements of the present invention, as shown in FIGS. Alternatively, the thickness Ta of the rigid plates 11 (the rigid plates disposed in the region A in FIGS. 3 and 4) located on both height direction end sides is located on the center side in the height direction from these rigid plates 11. The thickness of the rigid plate 12 (the rigid plate arranged in the region B in FIGS. 3 and 4) is larger than the thickness Tb. Preferably, the number of rigid plates on the height direction end side is one side. It is preferable that the thickness of these rigid plates satisfies the formula (1).

1.3 ≦ Ta / Tb ≦ 3.0 (1)

  Here, the number of rigid plates is 1/5 or less of the total number, but when the value obtained by dividing the total number by 5 is not an integer, the upper limit of the number is determined by rounding up this value.

  The reason why the thickness Ta of the rigid plate 11 is made larger than the thickness Tb of the rigid plate 12 is as follows. That is, when the total height of the laminated support is fixed, in order to obtain a necessary amount of shear deformation, it is advantageous that the total thickness of the rubber layer is thick. For that purpose, it is preferable that the rigid plate is as thin as possible. On the other hand, as described above, the bending moment becomes maximum at the end portion and becomes smaller toward the center in the height direction. Therefore, the thickness of the rigid plate, which plays a dominant role in the bending moment, is also thinned at the end portion. This is because it is preferable to increase the thickness as it goes, and if the rigid plate at the end is thin, it tends to buckle.

  In addition, the number of rigid plates at the end with Ta as one or more and 1/5 or less of the total number is increased by increasing the thickness of the rigid plate near the center in the height direction. However, the effect is almost unchanged for a bending moment that is large at the end and small at the center, and that Ta / Tb is preferably set to 1.3 to 3.0 because Ta / Tb is less than 1.3. In this case, the effect of preventing buckling is not sufficient, and if this exceeds 3.0, the steel plate at the end becomes too thick and the seismic isolation effect by the rubber layer is sacrificed accordingly. Because it will be.

  In addition to increasing the thickness of the rigid plate at the end, it is also important to use a material with high rigidity as a countermeasure against the problem that high damping performance rubber has low hardening, for example, Considering the cost, it is preferable to use a steel plate.

  Furthermore, as a countermeasure to this problem, it is preferable that the rubber layer 1 has a shape that is not easily buckled. Quantitatively, FIG. 7 shows an enlarged cross-sectional view of a portion where the rubber layer and the rigid plate are laminated. As described above, the ratio of the diameter Dr of the rigid plate to the height Hr of the rubber layer 1 is preferably 5.0 or more.

  In the laminated support shown in FIG. 4, steel plates were used as the rigid plates, and three types of laminated supports having different thicknesses of the rigid plates were prepared, and these were used as Examples 1, 2 and Comparative Examples. . In the example, the same number of rigid plates on both ends were made thicker and the rest were made thinner. In the comparative example, all the rigid plates had the same thickness. Based on the test method of ISO22762 (Ultimate Shear Properties), a shear strain-shear stress curve diagram was drawn to investigate the occurrence of buckling.

  For Examples 1 and 2 and Comparative Example, the number of rigid plates (the number per end on the end side) for the height direction end side and the center side, the thickness of the rigid plate, and the occurrence of buckling The presence or absence of is shown in Table 1. Moreover, the shear strain-shear stress curve obtained at this time is shown in FIG. The test was carried out with a shear strain piece amplitude γmax of 350% at the maximum. This is because the overlap of the pressure receiving portions of the upper and lower flanges 4 (dimension D in FIG. 4) when the shear strain is 350% is zero. Because it becomes.

  The number of rigid plates was 28, the diameter was 225 mm, and the rubber layer had the same thickness of 2.2 mm for all samples. The total height (H dimension in FIG. 4) of the comparative laminated support having a uniform rigid plate thickness was 91.8 mm. As a rubber material, a natural rubber-based laminated rubber having G (100%) of 0.4 MPa and G (250%) / G (100%) of about 0.92 was used. The shear strain amplitude γmax at which G (γmax) of this rubber material becomes G (100%) was about 310%.

  As apparent from FIG. 8, the comparative example has a 330% strain and the shear elastic modulus turned negative, and it can be seen that buckling occurs at this point. On the other hand, Examples 1 and 2 do not cause such buckling reduction.

It is sectional drawing which shows the conventional laminated support body in the state to which the excitation force acted. It is a moment distribution diagram which shows distribution of the bending moment which acts on a laminated support body. It is sectional drawing which shows the lamination | stacking support body of embodiment which concerns on this invention in the state which the horizontal excitation force is not acting. It is sectional drawing which shows the lamination | stacking support body of embodiment which concerns on this invention in the state which carried out the exciting force and was greatly sheared and deformed. It is a figure which shows typically the shear strain-shear stress curve of a rubber material. FIG. 6 is a diagram schematically showing the relationship between shear strain piece amplitude γmax and G (γmax) / G (100%). It is sectional drawing which expands and shows the part which laminated | stacked the rubber layer and the rigid board. It is the shear strain-shear stress curve figure obtained by measuring about an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rubber layer 2 Rigid board 3 Laminated body 4 Flange 5 Cover rubber layer 6 Structure 10 Laminated support 11, 12 Rigid board

Claims (4)

In a laminated support formed by alternately laminating rubber layers and rigid plates,
The rubber material of the rubber layer has a point corresponding to the strain of + γmax in the shear strain-shear stress curve diagram in the third cycle when a vibration is input such that the amplitude of the shear strain piece is γmax, and the strain of −γmax. When the slope of the straight line connecting the points corresponding to is defined as the equivalent shear modulus G (γmax), G (γmax) is equal to G (100%) corresponding to the shear strain piece amplitude of 100%. The half amplitude γmax does not exist in the region exceeding 100%, or even if it exists, it exists in the region exceeding 250%,
A laminated support characterized in that the thickness Ta of the rigid plate located on one or both of the height direction ends is larger than the thickness Tb of the rigid plate located on the center side in the height direction from these rigid plates. When m is an integer obtained by dividing the total number of rigid plates by 5 (if the divided value is not an integer, the number after the decimal point is rounded up), the number of rigid plates at the end in the height direction is 1 per side. The laminated support according to claim 1, wherein the number is m or less and the thickness of the rigid plates satisfies the formula (1).

1.3 ≦ Ta / Tb ≦ 3.0 (1)
  The laminated support according to claim 1 or 2, wherein the rigid plate is made of a steel plate.   The laminated support according to any one of claims 1 to 3, wherein the diameter of the rigid plate with respect to the total thickness of the rubber layer is less than 5.0.

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