JP3633351B2 - Isolation structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vibration isolation structure configured to perform vibration isolation on a vibration isolation object provided on a base portion via a vibration isolation device disposed between them.
[0002]
[Prior art]
In general, a base-isolated building constructed as a middle or high-rise building has an isolation device interposed between the foundation and the building. As this vibration isolator, laminated rubber is generally used, but there are also a sliding bearing and a rolling bearing that smooth the horizontal movement of the building. By the way, when a rocking motion occurs in a base-isolated building, a pulling force is generated in the vibration isolator, but the conventional vibration isolator has no way of resisting such a pulling force, and the original vibration isolating effect. You will not be able to get.
[0003]
Therefore, in recent years, as disclosed in Japanese Patent Application Laid-Open No. 10-280729, there is provided a vibration isolating structure in which an anti-extraction device (tensile force compatible device) that resists an extraction force is provided between the foundation and the building. Proposed. In this pull-out prevention device, a lower guide rail and an upper guide rail that are arranged to face each other at a right angle are fixed to a foundation portion and a building side, and a pull-out restraining portion is provided between the lower guide rail and the upper guide rail. It is designed to be provided. This pull-out restraining part is movably connected along both guide rails to allow horizontal displacement in all directions of the building and to prevent the two guide rails from being separated from each other. It comes to stop.
[0004]
[Problems to be solved by the invention]
However, in such a conventional vibration isolating structure, the pull-out preventing device provided with the pull-out restraining portion resists the pulling force acting on the building, and the original vibration-isolating function of the vibration-isolating device such as laminated rubber is effective. It can be demonstrated to. However, in this pull-out prevention device, the upper and lower guide rails are provided to horizontally displace the pull-out restraining portion, so that the configuration is remarkably complicated and the construction cost increases. Will be.
[0005]
By the way, in order to resist the pulling force, it is only necessary to introduce a prestress to the spring member by interposing a spring member between the foundation and the building. PC steel bars and PC steel wires to be used will be used. However, when pre-stress is applied using these PC steel bars and PC steel wires, spring members are caused by expansion and contraction due to temperature changes of laminated rubber, height change due to creep, and horizontal deformation of the vibration isolator due to wind and earthquake. If the prestress load that has been set changes due to the elongation of the material, it is difficult not only to maintain the prestress at a constant level, but also when the spring member is considerably pulled and its restoring force becomes too great during an earthquake, etc. However, there is a problem that the horizontal movement of the building is restricted, and thus the behavior of the vibration isolator is restricted, and the function cannot be sufficiently extracted.
[0006]
Therefore, the present invention has been made in view of such a conventional problem, and a spring member that applies prestress between a base portion and a vibration isolation object has a load with small load fluctuations relative to the amount of expansion and contraction thereof. A pull-out resistance force is made constant by using a device with a fixed area, thereby simplifying the structure of the pull-out prevention device and preventing the pull-out prevention device from affecting the behavior of the vibration isolator. The object is to provide a vibration structure.
[0007]
[Means for Solving the Problems]
In order to achieve such an object, the vibration isolating structure of the present invention is configured such that the vibration isolating object 3 is supported on the base 1 via the vibration isolator 2 as shown in FIG. In the vibration isolating structure in which an anti-extraction device 4 that resists an extraction force acting on the anti-vibration device 2 is provided between the object 3 and the anti-extraction device 4, the load is constant with a small load variation with respect to the vertical displacement. It comprises using the spring member 5 provided with the area | region, The prestress which resists a drawing-out force was added between the base part 1 and the isolation object 3 within the load constant area | region of this spring member 5, It is characterized by the above-mentioned. .
[0008]
Therefore, according to this configuration, a pre-stress that resists the pulling force is added to the spring member 5 constituting the pull-out prevention device 4 within a constant load range in which the load variation with respect to the vertical displacement amount of the spring member 5 is small. Therefore, even when the distance between the base portion 1 and the vibration isolation object 3 changes due to the generation of the pulling force, it can be resisted by a substantially constant prestress. Therefore, not only when a pulling force acts on the vibration isolator 2, but also when a temperature expansion or contraction or creep occurs in the vibration isolator 2, or due to horizontal deformation of the vibration isolator 2 due to wind or earthquake, the spring member Even when 5 is stretched, the prestress introduced between the base portion 1 and the vibration isolation object 3 can be kept constant. In addition, as described above, even if the spring member 5 is considerably pulled during an earthquake or the like, the spring member 5 is stretched within the range of the constant load region, so that fluctuations in its restoring force can be suppressed. It is possible to prevent the original vibration isolation function of the vibration isolation device 2 from being deteriorated without restricting the horizontal movement of the vibration target 3 and thus restricting the behavior of the vibration isolation device 2. Further, since the pulling force acting on the vibration isolator 2 can be resisted by prestress applied to the spring member 5, the pull-out preventing device 4 is basically provided with the spring member 5, and the configuration thereof is remarkably simplified. be able to.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 2 to 7 show an embodiment of the vibration isolation structure of the present invention, FIG. 2 is an enlarged sectional view of a main part of the vibration isolation structure, FIG. 3 is an enlarged perspective view of a spring member, and FIG. 4 is a spring characteristic of the spring member. FIG. 5 is a front view of a support portion of a spring member used in the vibration isolation structure, FIG. 6 is a plan view of the support portion, and FIG. 7 is a state in which the vibration isolation device is deformed in the vertical direction and in the horizontal direction. It is explanatory drawing shown.
[0010]
The basic structure of the vibration isolation structure of the present invention is that the base object 10 supports the vibration isolation object 12 via the vibration isolation device 14, and the vibration isolation object is interposed between the base part 10 and the vibration isolation object 12. A pull-out prevention device 22 that resists a pull-out force acting on the device 14 is provided, and the pull-out prevention device 22 is configured by using a spring member 24 having a constant load region in which the load variation with respect to the vertical displacement amount is small. Then, a prestress that resists the pulling force is applied to the spring member 24 between the base portion 10 and the vibration isolation object 12 within the constant load region of the spring member 24.
[0011]
That is, the vibration isolation structure of the present invention is shown by way of example when applied to a building constructed as a middle or high-rise building, and as shown in FIG. 2, the foundation 10 and the building 12 as a vibration isolation object A laminated rubber 14 as a vibration isolator is disposed between the building 12 and the building 12 is supported by the foundation 10 through vibration isolation.
[0012]
The foundation portion 10 is constructed as RC by placing concrete on the excavation portion of the ground, and a mounting base 16 for the laminated rubber 14 projects from the upper surface thereof. In addition, the steel beam 18 provided at the lower end of the building 12 is supported on the laminated rubber 14. The steel beam 18 is formed of H-shaped steel, and the laminated rubber 14 is formed on the lower surface of the lower flange 18a. The support base 20 is vertically provided. On the other hand, as is generally known, the laminated rubber 14 is configured by attaching mounting plates 14b and 14c to upper and lower ends of a main body portion 14a in which rubber layers and steel plates are alternately laminated, and an upper mounting plate. 14 b is fixed to the support base 20, and the lower mounting plate 14 is fixed to the mounting base 16.
[0013]
A pull-out prevention device 22 is provided between the base portion 10 and the steel beam 18 in the vicinity of the laminated rubber 14. Although only one pull-out prevention device 22 is shown in the drawing, it is actually desirable to arrange it symmetrically in the extending direction of the steel beam 18 with the laminated rubber 14 as the center. For example, when the laminated rubber 14 is disposed in a straight portion of the steel beam 18, two pull-out preventing devices 22 are provided in the extending direction of the steel beam 18 with the laminated rubber 14 interposed therebetween, and the steel beam 18 is cross-shaped. In the case where the laminated rubber 14 is arranged at the intersection, the four pull-out prevention devices 22 are provided point-symmetrically along the cross-shaped steel beam 18.
[0014]
The pull-out preventing device 22 uses a spring member having a constant load region in which the load variation with respect to the vertical displacement amount is small. In this embodiment, a coil spring 24 is applied as the spring member as shown in FIG. A spring member having a constant load region has a restoring force characteristic that makes a force (load) substantially constant even when the spring member expands and contracts by a predetermined amount, and such a spring member can be designed.
[0015]
That is, such a coil spring 24 is set as a spring characteristic having a restoring force that becomes nonlinear with a large initial elastic gradient and a small second-order gradient, and as shown in FIG. 4, from a natural length (displacement δ = 0). In the initial stage where the load (P) is applied, it suddenly rises and the change range of the load (P) increases with respect to a certain amount of displacement (δ), but in the corresponding displacement region R, the slope of the load (P) is gentle. It becomes. That is, in the region R where the slope is gentle, the change width (ΔP) of the load (P) with respect to a certain amount of displacement (δ) is small, and this region R is used as the constant load region.
[0016]
The coil springs 24 are arranged in the vertical direction. PC steel bars 26 and 26a having appropriate lengths are connected to the upper and lower ends of the coil springs 24, and the PC steel bars 26 and 26a at both ends are respectively connected to ball seats. It attaches to the foundation 10 and the steel beam 18 via 28 and 28a. The lower ball seat portion 28a is attached downward to an anchor base 32 embedded and fixed to the base portion 10 via anchor bolts 30, and the upper ball seat portion 28 is fixed to the upper surface of the lower flange 18a of the steel beam 18. It is attached upward to the fixed base 32a. At this time, the upper end of the PC steel bar 26 is penetrated upward from an opening 18b formed in the lower flange 18a.
[0017]
The upper and lower ball seats 28 and 28a are of the same configuration and are used upside down. The ball seats 28 and 28a are connected to the rotating unit 34 as shown in FIGS. And a ball base 36. The rotating portion 34 has an insertion hole 34b formed in the center of the spherical convex portion 34a, and the end portions of the PC steel rods 26 and 26a are inserted into the insertion hole 34b and fixed by nuts 38. On the other hand, the spherical base 36 has a large-diameter opening 36b formed at the center of the spherical recess 36a that receives the spherical protrusion 34a of the rotating portion 34, and the spherical protrusion 34a is slidable in the spherical recess 36a. While being fitted, the PC steel bars 26 and 26a are penetrated through the opening 36b. A plurality of mounting holes 36c are formed in the peripheral edge portion of the ball seat base 36, and are fixed to the fixing bases 32 and 32a via bolts 40 inserted through the mounting holes 36c.
[0018]
The coil spring 24 is set so that prestress is introduced in the constant load region R by tightening and adjusting the nuts 38 of the ball seats 28 and 28a. With this prestress, the foundation 10 and the building 12 are set. It resists the pulling force acting between the two.
[0019]
With the above-described structure, in the vibration isolating structure of the present embodiment, when a pulling force acts on the building 12 and the vertical distance between the foundation 10 and the steel beam 18 is about to be widened, the pulling prevention is performed. The coil spring 24 of the device 22 resists this and prevents the building 12 from lifting. Since the pull-out preventing device 22 can resist the pull-out force due to the prestress introduced into the coil spring 24, the pull-out preventing device 22 may basically be provided with the coil spring 24, and the configuration thereof can be greatly simplified.
[0020]
In particular, in this pull-out prevention device 22, prestress that resists the pull-out force is applied to the coil spring 24 in the range of a constant load region in which the load fluctuation with respect to the vertical displacement amount is small. ), Even if expansion and contraction ΔLT or creep ΔLC due to temperature occurs in laminated rubber 14, the introduced prestress does not fluctuate, and the prestress initially set for the pulling force is appropriate. Can resist. Similarly, as shown in FIG. 5B, even when a considerable elongation ΔLH occurs in the coil spring 24 due to the earthquake, fluctuations in prestress can be suppressed and resistance to the pulling force can be appropriately resisted. .
[0021]
Further, even when the laminated rubber 14 is deformed in the horizontal direction during an earthquake or the like and the coil spring 24 is considerably pulled, the coil spring 24 expands within the range of the constant load region R, so that the fluctuation of the restoring force is small. The horizontal movement of the building 12 is constrained, and hence the behavior of the laminated rubber 14 is not restricted, and the original vibration-isolating function of the laminated rubber 14 can be prevented from being lowered.
[0022]
Here, in the case of horizontal deformation due to an earthquake, the coil spring 24 of the pull-out prevention device 22 is inclined with the horizontal deformation amount ΔLH as described above, and this inclination is the ball seat portion 28 as shown in FIG. , 28a. That is, when the tilting force is input to the ball seats 28 and 28a via the PC steel rods 26 and 26a, the rotating part 34 is accompanied by sliding between the spherical convex part 34a and the spherical concave part 36a. As shown in FIG. For this reason, at the time of horizontal deformation, the coil spring 24 can be expanded and contracted without bending deformation, and the original spring characteristic can be exhibited to prevent the vibration isolation performance of the laminated rubber 14 from being affected.
[0023]
By the way, in the said embodiment, although the case where the coil spring 24 was used as a spring member was disclosed, not only this but the spring provided with the spring characteristic provided with the constant load area | region with a small load fluctuation | variation with respect to an up-down direction displacement amount may be sufficient. For example, a disc spring has a spring characteristic with a constant load region, and this disc spring can be used as the spring member of the present invention.
[0024]
FIG. 8 shows another embodiment, in which the present invention is applied to a bridge 50. That is, in this embodiment, the bridge 50 as a vibration isolation object is supported by the bridge pier 54 as the foundation through the laminated rubber 52, and the pull-out prevention device 56 is provided between the bridge 50 and the pier 54. An isolation structure is constructed. Of course, even in this embodiment, the pull-out prevention device 56 uses the spring member 58 having a constant load region in which the load variation with respect to the vertical displacement amount is small, and within the constant load region of the spring member 58, the bridge 50 and A prestress that resists the pulling force is added between the bridge piers 54. Here, as the spring member 58, as disclosed in the above embodiment, a coil spring, a disc spring, or the like is used.
[0025]
Therefore, in this embodiment, even when a pulling force is applied to the laminated rubber 52 due to wind buffing, the pulling prevention device 56 resists this pulling force, whereby the vibration isolating function of the laminated rubber 52 is achieved. Can be prevented from being lowered.
[0026]
【The invention's effect】
As described above, in the vibration isolation structure of the present invention, even when the distance between the base portion and the vibration isolation object changes due to the generation of the pulling force, the pulling force is resisted by a substantially constant prestress. can do. In particular, even if temperature expansion or contraction or creep occurs in the vibration isolator, or if the spring member is stretched due to horizontal deformation of the vibration isolator due to wind or earthquake, the foundation and the object to be isolated Prestress introduced between objects can be kept constant. In addition, even if the spring member is pulled considerably along with the horizontal displacement of the vibration isolator during an earthquake, etc., the spring member expands within the range of a constant load, so that fluctuations in its restoring force can be suppressed, and The horizontal movement of the object is restrained, and hence the behavior of the vibration isolator is not restricted, and the original vibration isolating function of the vibration isolator can be prevented from being deteriorated. Further, since the pulling force acting on the vibration isolator can be resisted by prestress applied to the spring member, the pull-out preventing device may basically be provided with the spring member, and the configuration thereof can be greatly simplified.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a basic structure of a vibration isolation structure of the present invention.
FIG. 2 is an enlarged cross-sectional view of a main part showing an embodiment of the vibration isolation structure of the present invention.
FIG. 3 is an enlarged perspective view showing an example of a spring member used in the present invention.
FIG. 4 is a graph showing an example of spring characteristics of a spring member used in the present invention.
FIG. 5 is a front view showing an example of a support portion of a spring member used in the present invention.
FIG. 6 is a plan view showing an example of a support portion of a spring member used in the present invention.
FIG. 7 is an explanatory view showing a state where the vibration isolator used in the present invention is deformed in the vertical direction or in the horizontal direction.
FIG. 8 is a schematic configuration diagram showing another embodiment of the vibration isolation structure of the present invention.
[Explanation of symbols]
10 foundation 12 building (object to be isolated)
14 Laminated rubber (isolation device)
22 Pull-out prevention device 24 Coil spring (spring member)
50 bridge (object to be isolated)
52 Laminated rubber (object to be isolated)
54 Pier (foundation)
56 Pull-out prevention device 58 Spring member

Claims (1)

The base is supported by an isolation device via an isolation device, and an anti-extraction device is provided between the foundation and the isolation object to prevent extraction force acting on the isolation device. In the vibration structure,
The pull-out prevention device is configured by using a spring member having a constant load region in which the load variation with respect to the vertical displacement amount is small, and the pull-out force between the foundation portion and the isolation object is within the constant load region of the spring member. A vibration isolation structure characterized by the addition of prestressing resistance.

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