JP6169659B2 - Displacement limiting device used for seismic isolation structure and method of introducing pre-compression - Google Patents

Description

  The present invention is used in combination with a laminated rubber-based seismic isolation device in a base-isolated building structure, whether newly installed or existing, and a pre-compression is introduced to prevent damage due to excessive deformation of the laminated rubber-based seismic isolation device. The present invention relates to a displacement limiting device and a pre-compression introducing method.

  As a base-isolated building structure, the base structure and the top structure are separated, and a base isolation layer is formed between which the base isolation device is installed. Generally, seismic isolation devices are roughly divided into two devices, an isolator and a damper, and there are two types, a laminated rubber type and a sliding type. Some isolators also have a damper function. Sliding systems include sliding bearings and rolling bearings, but laminated rubber is often used as a seismic isolation device. This type of seismic isolation device is one in which thin rubber plates and steel plates are alternately laminated and bonded, and is flexible in the horizontal direction and has a seismic isolation function that returns to its original position even when deformed. However, it is hard in the vertical direction and can sufficiently support the load of the superstructure.

  A plurality of conventional techniques are known as laminated rubber-based seismic isolation devices. For example, as a first prior art, a laminated rubber body is formed by laminating a number of thin rubber layers and steel plates, and lead having a purity of 99.9% or more is filled and press-fitted into the hole in the center. That is, a plastic material core made of a rod-like superplastic metal that is fitted through the laminated rubber body in the center of the plane of the upper laminated rubber body is configured. The shape of the lead core is shown here for the conventional type having the same cross-sectional area over the entire height. Usually, a cylindrical shape is adopted. The lead core is sealed in rubber and a steel plate, and is in close contact with the lead and the rubber / steel plate by the action of a vertical load (see the description in FIG. 1 of Patent Document 1).

  According to this laminated rubber-based seismic isolation device, when a horizontal force acts during an earthquake, the laminated rubber body undergoes shear deformation in the horizontal direction as shown in the figure, and the blunt core also undergoes horizontal shear deformation due to the shear deformation of the laminated rubber body. To be forced. At this time, as shown in the figure, when the rubber material is natural rubber, the horizontal restoring force characteristic of the laminated rubber body shows an elastic rigidity with a substantially wire diameter up to a shear strain y = 250%, and then gradually hardens. It is said that it is a general characteristic to show a tendency to rupture and to break at around y = 400%.

  Further, as a second related art that is publicly known, it is for solving the problem of the seismic isolation device using a large laminated rubber, and there are disk-shaped connecting steel plates on both sides of the cylindrical laminated rubber. One or both of the fixed laminated rubber body and the connecting steel plates fixed to the plurality of laminated rubber bodies are connected steel plates provided with flanges, and the laminated rubber is provided so that the connecting steel plates provided with the flanges face each other. A plurality of members for connecting the flanges to form a multi-stage laminated rubber assembly, and a plurality of engaging means for engaging with about a half circumferential portion of each flange of the plurality of multi-stage laminated rubber assemblies having the connecting means. One or a plurality of connection stabilizers for connecting the flanges of the plurality of multi-stage laminated rubber assemblies when the multi-stage laminated rubber assembly is formed by the coupling means. Multi-stage A seismic isolation unit using the mounting steel plate secured to the upper and lower connecting steel layer rubber assembly, the laminated rubber composed of (see Patent Document 2).

  According to this seismic isolation unit, it is possible to take seismic isolation measures for large or huge structures using laminated rubber having a relatively small diameter, for example, about 70 cm in diameter and having excellent breaking performance. In addition, since it is possible to easily disassemble the connecting portion that connects a plurality of seismic isolation units, maintenance and maintenance management of the laminated rubber after construction becomes extremely easy. Compared with the production of large-sized laminated rubber, the manufacturing cost can be greatly reduced and the quality can be improved and made uniform, which is advantageous from the viewpoint of quality assurance. It can be planned.

JP 2003-21193 A JP 2003-343649 A

  However, the laminated rubber seismic isolation devices disclosed in the first and second prior arts are not only expensive, but are arranged at the column base positions via footings to support the vertical load of the building. . If the equipment is damaged or damaged due to over-deformation in the event of a secular deterioration of the rubber or a large earthquake that exceeds the design assumptions, it will be a large-scale construction to replace and the cost will be high. There is a problem that it takes.

  Moreover, in existing seismic isolation buildings, the earthquake assumed in the design at that time is lower than the current huge earthquake, so that the seismic isolation device itself is not only damaged due to excessive deformation of the seismic isolation device, but also the building is shaken. There is also a report that it cannot be used unless it is reinforced because it does not stop and over-displaces.

  Recently, it was discovered that seismic isolation devices with insufficient performance were used in existing buildings. In this case, the existing building cannot be used unless the defective seismic isolation device is replaced because it does not have the seismic isolation performance as designed. However, since existing buildings are not designed to be able to replace seismic isolation devices from the beginning, it is virtually impossible to replace all seismic isolation devices. The need for reinforcement of seismic performance is required as a real problem.

  Therefore, the present invention limits overdeformation of an existing (conventional) laminated rubber-based seismic isolation device even if it encounters a huge earthquake that is larger than expected in design or in an existing building where the seismic isolation performance is insufficient. An object of the present invention is to provide an inexpensive, simple and replaceable small displacement limiting device that prevents damage to the superstructure together with the seismic isolation device, and a manufacturing method related to the device.

As a specific means for achieving the above object, the present invention provides a base-isolated building structure in which a base-isolation device is interposed between a lower structure and an upper structure. A displacement limiting device installed between a lower structure and an upper structure and preventing damage due to excessive deformation of the seismic isolation device, the displacement limiting device comprising a main body portion and a base plate formed of an elastic body. A jack installed between the large beam connecting the footing of the upper structure and the mat slab or adjustment block of the lower structure, and between the large beam and the base plate, or between the mat slab or adjustment block and the base plate. By jacking up, the required pre-compression is introduced and maintained in the main body, and between the main body of the displacement limiting device and the upper structure or the lower structure. There is provided a displacement limiting device is characterized in that so as to produce the required frictional force.

  In the first invention, a required friction force is generated between the main body portion of the displacement limiting device and the upper structure or the lower structure by the pre-compression introduced into the elastic body; The body is one of hard rubber, natural rubber, synthetic rubber, and high damping rubber, and a mesh material made of PC wire or PC steel is a multi-stage laminated rubber; the mesh material is An additional requirement is to form a lattice or spiral.

According to a second aspect of the present invention, there is provided a seismic isolation building structure in which a seismic isolation device is interposed between the lower structure and the upper structure, and is installed between the lower structure and the upper structure. A pre-compression introducing method of a displacement limiting device for preventing damage due to excessive deformation of a seismic device, the displacement limiting device comprising a main body portion and a base plate formed of an elastic body, and connecting a large beam between the footings of the upper structure required to the main body by a placed between the mat slabs or adjustment block substructures, jacking up the installed jack between the between the girders and the base plate or mat slab or adjustment block and the base plate, The pre-compression is introduced, and the introduced pre-compression is maintained without loosening the jack. Pre compression method of introducing the displacement limiting device which is intended to provide.

The displacement limiting device according to the present invention has the following effects.
1. In an existing building, a predetermined frictional force is generated on the contact surface between the displacement limiting device and the superstructure (the underground beam) by installing the displacement limiting device to which the pre-compression of the present invention is introduced. The frictional force becomes a resistance force (restoring force) against the seismic force, restricts excessive deformation of the existing seismic isolation device, and can prevent the superstructure together with the seismic isolation device from being damaged or broken.
2. In a new building, the safety of a conventional seismic isolation device can be greatly enhanced by installing a displacement limiting device into which the pre-compression of the present invention is introduced. Or, in terms of design, the conventional expensive seismic isolation device can be reduced in size, and the overall cost can be reduced.
3. Since the displacement limiting device of the present invention solves the necessary method of introducing axial compression force, it can be installed in places where there is no axial force, and is cheaper and easier to construct than conventional seismic isolation devices. It becomes a simple and replaceable small device.
4. Since the displacement limiting device of the present invention does not serve to support the vertical load of the building, if it is designed to be broken before the conventional expensive seismic isolation device installed at the column base position to absorb the seismic energy The conventional seismic isolation device can be protected from the earthquake. Since the displacement limiting device of the present application is inexpensive and easy to install and replace, the displacement limiting device can be quickly recovered after a huge earthquake occurs.
5. The elastic material can greatly improve the tensile strength and elastic deformation performance of the elastic body by using laminated rubber that is synthesized by putting mesh material made of PC wire or PC steel wire into rubber. In addition, a shear deformation capability equal to or higher than that of a conventional natural laminated rubber-based seismic isolation device can be obtained, and a shear resistance (restoring force) due to the shear deformation of rubber can be increased. In terms of cost, the cost is lower than that of a laminated rubber formed by alternately stacking conventional steel plates and natural rubber.

In addition, by putting mesh material in the elastic material, it can be ensured that the pre-compression introduced in the vertical direction is securely held while the rubber is shearing in the horizontal direction. Will not be fluctuated or lost.
Furthermore, by making the mesh material spiral, there is no direction dependency compared to the lattice shape, the mesh streaks can work evenly against seismic forces in all directions, and the strength and deformation performance of the laminated rubber elastic material are full. Can be demonstrated.

It is the side view which showed schematically the principal part of the seismic isolation building structure provided with the displacement limiting apparatus which concerns on the 1st Embodiment of this invention. In the base-isolated building structure provided with the displacement limiting apparatus which concerns on the embodiment, it is the side view which showed schematically the displacement condition at the time of receiving an earthquake. It is the side view which showed schematically the principal part of the seismic isolation building structure provided with the modified example of the displacement limiting apparatus which concerns on the said 1st Embodiment. In the base-isolated building structure provided with the modification example of the displacement limiting apparatus which concerns on the embodiment, it is the side view which showed schematically the displacement condition when receiving an earthquake. BRIEF DESCRIPTION OF THE DRAWINGS The 1st Example of the preferable elastic body used for the displacement limiting device of this invention is shown, (1) is the top view shown schematically and (2) is the longitudinal cross-sectional view shown schematically. is there. The 2nd Example of the preferable elastic body used for the displacement limiting apparatus of this invention is shown, (1) is the top view shown schematically and (2) is the longitudinal cross-sectional view shown schematically. is there. It is a top view of the base-isolated building structure which showed the example of arrangement of the displacement limit device of the present invention roughly.

  The present invention will be described in detail based on a plurality of illustrated embodiments. First, the displacement limiting device according to the first embodiment in the base-isolated building structure shown in FIGS. In FIG. 1, as a base-isolated building structure, a laminated rubber type main base-isolation device 3 is arranged between the lower structure 1 and the upper structure 2, and the lower structure 1 is the head of a pile 5 driven into the ground 4. A mat slab 7 that covers the periphery of the head of the pile 5 and the upper surface of the ground 4 is formed. The superstructure 2 is provided with footings 9 that support the pillars 8 of the building, and is provided with a large beam (underground beam) 10 that connects between the respective footings 9, and a slab is formed on the upper surface of the large beam (underground beam) 10. 11 is formed. And the seismic isolation device 3 is installed between the pile foundation 6 of the pile head which is the lower structure 1 and the footing 9 which is the upper structure 2, and the mat slab 7 of the lower structure 1 and the girder of the upper structure 2 (underground Between the beam (10) is a pit as the seismic isolation layer A.

  Further, pre-compression is introduced at a required position of the pit formed in the seismic isolation layer A, and a displacement limiting device 12 for preventing damage and breakage due to excessive deformation of the laminated rubber type seismic isolation device 3 is disposed. . This displacement limiting device 12 is formed of a body portion 13 and a base plate 14 made of an elastic body, and a jack 15 having a required output is installed on the bottom surface of the base plate 14 with the top surface of the body portion 13 in contact with the bottom surface of the large beam 10. Then, an adjustment block 16 for adjusting the height is installed between the jack 15 and the mat slab 7 and adjusted to a required height. The required frictional force F is generated on the contact surface between the main body 13 of the displacement limiting device 12 and the large beam 10 by jacking up and introducing the pre-compression P into the main body 13 which is an elastic material.

  As shown in FIG. 2, this frictional force F resists to suppress the relative displacement generated between the upper structure 2 and the lower structure 1 at the time of a huge earthquake, and always tries to return to the original position. It becomes a resilience. This friction force F is the product of the friction coefficient k and the pre-compression P (F = k · P). By adjusting the friction coefficient k and the pre-compression P, the friction force F can be generated in accordance with a required magnitude.

  Therefore, in the existing building, if there is a possibility that the existing seismic isolation device 3 may cause excessive displacement in the seismic isolation layer A due to insufficient performance, the displacement limiting device 12 is installed to compensate for the lack of performance. I will do it. The number of installations and the frictional force F per unit are calculated from the necessary damping force (restoring force), and the required pre-compression P can be introduced by the jack 15. For example, if the damping force (restoring force) with which the performance of the existing seismic isolation device 3 is insufficient is 80 tons per unit, if four displacement limiting devices 12 are evenly arranged around the seismic isolation device 3 When the frictional force F required per piece is 20 tons and the friction coefficient k = 0.5, the pre-compression P is 20 tons.

  In the case of a new building, by installing the displacement limiting device 12 along with the seismic isolation device 3 installed on the leg of the column 8, the burden on the seismic isolation device 3 installed on the leg of the column 8 is reduced. The cost can be reduced by reducing the size. Moreover, the displacement limiting device 12 can be installed as a safety factor for the entire seismic isolation layer A, and the seismic isolation device 3 can be protected from the earthquake. Furthermore, if the displacement limiting device 12 is designed to be broken before the seismic isolation device 3, the seismic isolation device 3 can be prevented from being damaged. Since the displacement limiting device 12 is inexpensive and can be easily replaced, it can be quickly recovered after an earthquake.

  In addition, the adjustment block 16 is preferably made of steel or concrete with a hollow box cross section and the like, and is lightweight. Depending on the workability and exchangeability, the bolts 17 are fixed to the slab 7. The displacement limiting device 12 is formed of the main body 13 and the base plate 14, but is not limited to this. For example, the upper surface of the main body 13 is further appropriately matched with a required friction coefficient. A suitable material may be selected and attached to the upper surface as an upper surface plate. In short, it is preferable to attach the base plate 14 to at least the lower surface (jack attachment side) of the main body 13. And in order to introduce a precompression into the main-body part 13 equally, it is preferable to make the base plate 14 into the steel plate which has required rigidity.

The displacement limiting device 12 has a planar shape that is circular or approximate to a circular shape so as not to depend on direction, and can cope with deformation in all directions during an earthquake.
The jack 15 may be a hydraulic jack such as a small screw jack or a bolt jack. It is not particularly limited, and it is preferable to use one that satisfies a required output and that is lightweight and small. In the embodiment, one unit is installed at the center of the displacement limiting device 12, but the present invention is not limited to this. For example, a plurality of units may be installed at four corners.

In addition, after jacking up, the following two methods are used to maintain the pressing force.
First, leave the jack on. In this case, it is desirable that the gauge 18 is attached and the output is periodically measured and constantly managed. In particular, after the occurrence of the earthquake, it is desirable to check the fluctuation of the output and the presence or absence of the loss with the gauge 18.

Secondly, a support material, for example, a steel support, is used to hold the pressing force in the four corners of the base plate 14, and the jack installed in the center is loosened and removed. Thereafter, non-shrink mortar or the like is filled between the base plate 14 and the adjustment block 16 and cured, and the cured mortar retains a pressing force instead of the jack. The removed jack can be reused and the cost can be reduced.
About the above two methods, it is desirable to comprehensively judge by the situation of the building, construction location, equipment, etc., and to select and implement the method means.

Next, a modified example of the displacement limiting device 12 in the first embodiment shown in FIGS. 3 and 4 will be described. Since most parts of this modified example are the same as those of the first embodiment, the same parts are denoted by the same reference numerals, and detailed description thereof will be omitted.
In this modified embodiment, the upper surface of the main body 13 and the lower surface of the girder (underground beam) 10 are arranged so that the displacement limiting device 12 can follow the deformation of the seismic isolation layer A when the seismic isolation layer A is deformed during a huge earthquake. The slip prevention member 19 is attached to the center of the contact surface. This slip prevention member 19 is fixed and integrated in advance as a steel plate on the lower surface of the girder (underground beam) 10 so as to be positioned when the main body 13 is mounted, and the main body 13 is greatly deformed during an earthquake. In the event that a sliding phenomenon occurs on the contact surface between the displacement limiting device 12 and the large beam (underground beam) 10, a supporting pressure is generated on the side surface in contact with the slip prevention member 19 and the sliding occurs. Play a role to stop. In addition, it is better to form the shape of the base plate 14 attached to the lower surface of the main body portion 13 so as to be familiar with the jack 15.

Next, the elastic body used as the main body of the present invention will be described with reference to a plurality of examples.
First, the elastic body used as the main body 13 is preferably made of hard rubber, but may be any of natural rubber, synthetic rubber or high damping rubber. In order to reduce the cost, it is desirable to use rubber chips or rubber obtained by recycling waste tires.
Further, in order to increase the shear strength and shear deformation ability of the rubber elastic body, it is preferable to use a synthetic rubber obtained by mixing carbon fiber with the above rubber material.

  In the first embodiment shown in FIGS. 5 (1) and (2), as the elastic body of the main body 13, the rubber material is made of a PC steel strand such as a PC steel wire, a PC steel material, or a PC wire. It is preferable to use a laminated rubber formed of multi-stage mesh material 24 formed in the above. It is optimal to introduce the pre-compression P and use it as the displacement limiting device 12 because the PC steel material has high strength, but the present invention is not limited to this, and high strength steel bars or fiber bars may be used.

In addition, as shown in FIGS. 6 (1) and (2), the use of the rubber material is not changed, but the mesh material 24 is not a lattice but a spiral PC wire or steel rod. In the same manner as described above, the laminated rubber structure is formed in multiple stages.
In the case of the grid-like mesh material 24 according to the above-described embodiment, when the elastic material at the time of earthquake undergoes shear deformation, the corresponding stress is transmitted by the resultant force of the PC steel material in the X and Y directions by the seismic force. . In contrast, in the case of the spiral mesh material 24 formed of a thin PC wire, there is no direction dependency and the mesh streaks work equally in all directions, and the strength and deformation ability of the elastic material can be fully exhibited. Most effective.

Next, an arrangement example of the displacement limiting device 12 in the base-isolated building structure will be described with reference to the plan view shown in FIG.
In the base-isolated building structure, a footing 9 in which front, rear, left and right are connected by a large beam 10 is provided at a position where each pillar 8 is built, and the main base-isolation device 3 is provided between the footing 9 and the wrinkle foundation 6. Yes. The displacement limiting device 12 of the present invention is installed between the large beam 10 and the mat slab 7 that have no axial force other than the column 8 but that strongly supports the building. In this case, only two large beams 10 are connected to the footing 9 at the corner of the building, but three large beams 10 are connected to the footing 9 on the side surface, and 4 to the footing 9 inside the building. The large beams 10 of the books are connected.

  In this type of seismic isolation building structure, the conventional main seismic isolation device 3 is, for example, a natural laminated rubber seismic isolation device installed at the corner and a side plug containing lead plugs. It is a natural laminated rubber seismic isolation device, and a sliding bearing type seismic isolation device is installed in the center. Since the displacement limiting device 12 of the present invention is installed in a place where there is no axial force other than the column 8, at least two or more around the column 8 per main seismic isolation device 3 on the building plane. It is preferable to arrange the four equally. In this way, the number of the devices can be increased and distributed throughout the device, so that the device itself can be reduced in size and weight. Of course, the required number can be freely selected and arranged according to the structure of the building and the state of the seismic isolation device 3.

The embodiment described above is not intended to limit the structural requirements (main point) of the present invention, and various modifications can be made without departing from the spirit of the present invention.
For example, in the illustrated embodiment, the upper end of the main body portion 13 of the displacement limiting device 12 is in contact with the lower surface of the girder 10, and a jack 15 having a required output is installed on the lower surface of the base plate 14, and the jack 15, the mat slab 7, Although the adjustment block 16 for adjusting the height is installed between the two, the arrangement is not limited to this, and the arrangement state is completely reversed, for example, the main body of the displacement limiting device 12 on the mat slab 7. 13 may be installed, and the adjustment block 16 may be attached to the girder 10 with the jack 15 interposed therebetween. In short, it is only necessary to generate a required frictional force between the main body 13 of the displacement limiting device 12 and the lower structure 1. Also in the second embodiment, the required frictional force can be generated between the main body 13 of the displacement limiting device 12 and the lower structure 1 by changing in the same manner.
Moreover, a pre-compression can be given to the main-body part 13 using a spring instead of a jack. Although illustration is omitted, for example, a compression coil spring having a required elastic reaction force is used, and the compression coil spring is elastically deformed in advance by using a restraining means such as a wire, and the main body portion in a state where the elastic compression deformation is performed. Set together according to the mounting position of 13, and after setting is complete, by cutting the restraining wire and releasing the restraint, the required elastic reaction force is released and the required pre-compression is introduced into the main body 13; A required frictional force can be generated between the main body 13 of the displacement limiting device 12 and the upper structure 2 or the lower structure 1.
In addition, the required frictional force in the present application is preferably a static frictional force generated between the main body 13 of the displacement limiting device 12 and the upper structure 2 or the lower structure 1, but is not limited thereto and is necessary. Accordingly, there may be a dynamic friction force generated while sliding between the main body 13 and the upper structure 2 or the lower structure 1.

  In the displacement limiting device 12 according to the present invention, since the main body 13 of the displacement limiting device 12 is an elastic body, the horizontal resistance force (restoring force) of the displacement limiting device 12 during an earthquake is the friction force F and the elasticity of the elastic body. Although it is a resultant force with the reaction force (shearing force) due to shear deformation, the purpose is to provide a displacement limiting device 12 that is inexpensive and lightweight, so the main horizontal resistance force (restoring force) is borne by the friction force F The main body 13 only needs to follow the displacement of the seismic isolation layer A. In short, the conventional laminated rubber-based seismic isolation device 3 is required to have a function of supporting a vertical load and a function of absorbing energy while performing horizontal deformation, so that an expensive material is used. limited. On the other hand, the displacement limiting device 12 of the present invention reinforces or assists the seismic isolation performance of the conventional seismic isolation device 3, and therefore does not need a function of supporting a vertical load. Although only the deformation of the portion 13 and the energy absorption performance are required, since the requirement for the reaction force (shearing force) is relaxed, the material characteristics of the elastic body can be selected from a wide range of materials, so it is inexpensive. It becomes possible to provide. This is due to different performance requirements from the conventional laminated rubber-based seismic isolation device 3, but can be widely applied or used in new or existing seismic isolation building structures of this type.

DESCRIPTION OF SYMBOLS 1 Substructure 2 Superstructure 3 Main seismic isolation device 4 Ground 5 Pile 6 Wrap base 7 Mat slab 8 Column 9 Footing 10 Large beam (underground beam)
11 Slab 12 Displacement Limiting Device 13 Main Body 14 Base Plate 15 Jack 16 Adjustment Block 17 Mounting Bolt 18 Gauge 19 Detachment Member 24 Mesh Material A Seismic Isolation Layer P Pre-compression F Friction Force k Friction Coefficient

Claims (4)

In the seismic isolation building structure in which the seismic isolation device is interposed between the lower structure and the upper structure,
A displacement limiting device that is installed between the lower structure and the upper structure and prevents damage due to excessive deformation of the seismic isolation device,
The displacement limiting device is composed of a main body portion formed of an elastic body and a base plate, and is installed between a large beam connecting the footings of the upper structure and the mat slab or the adjustment block of the lower structure,
By jacking up a jack installed between the large beam and the base plate, or between the mat slab or the adjustment block and the base plate, the required pre-compression is introduced and maintained in the main body, and the main body of the displacement limiting device A displacement limiting device characterized in that a required frictional force is generated between the upper structure and the lower structure. The elastic body is one of hard rubber, natural rubber, synthetic rubber, and high damping rubber, and is characterized in that it is a laminated rubber formed of multi-stage mesh material made of PC wire or PC steel material. The displacement limiting device according to claim 1. The displacement limiting device according to claim 2, wherein the mesh material has a lattice shape or a spiral shape. In the seismic isolation building structure in which the seismic isolation device is interposed between the lower structure and the upper structure,
A pre-compression introduction method for a displacement limiting device that is installed between the lower structure and the upper structure and prevents damage due to excessive deformation of the seismic isolation device,
The displacement limiting device is composed of a main body portion formed of an elastic body and a base plate, and is installed between a large beam connecting the footings of the upper structure and the mat slab or the adjustment block of the lower structure,
The jack is installed between the large beam and the base plate, or between the mat slab or the adjusting block and the base plate, thereby introducing the necessary pre-compression into the main body, and without introducing the loose jack. A precompression introducing method for a displacement limiting device, characterized by maintaining the precompression.

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