JP7168501B2 - Seismic Isolation Damper and Seismic Isolation Structure of Building Foundation Using It - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vibration isolation damper embedded in the concrete of the raised portion of a raft foundation or continuous foundation that supports the foundation of a building, and a vibration isolation structure of the building foundation using the damper.

2. Description of the Related Art As a seismic isolation structure for a building that protects a continuous foundation of a building by generating a vibration damping effect, for example, the structure disclosed in Patent Document 1 below is known.

The vibration isolation structure disclosed in Patent Document 1 intervenes vibration isolation means between the foundation of the building and the base supported by the foundation, and furthermore, arranges a curved metal connection member on the side of the foundation riser. One end of the connecting member is fixed to the base, and the other end is fixed to the raised portion of the base.

A common method of supporting the foundation is to fix the foundation to the rising portion of the foundation via anchor bolts planted in the concrete of the rising portion of the foundation. is not allowed.

On the other hand, the vibration isolation structure of Patent Document 1 allows horizontal displacement of the base with respect to the base by interposing vibration isolation means between the base and the base. In addition, the connection member is deformed when relative displacement occurs between the foundation and the base, and by allowing the relative displacement, the connection state of the base with respect to the foundation is ensured, and the vibration isolation effect is exhibited. .

JP 2008-280818 A

The seismic isolation structure of Patent Literature 1 protects an upper structure such as a building supported by a foundation from an external load such as an earthquake on the premise that the foundation is sound.

A general building with a steel frame or wooden foundation is installed by connecting the foundation with anchor bolts on the foundation rise of a raft foundation or continuous foundation, and the foundation rise will be damaged if a large external load is applied. can be considered.

On the other hand, when the horizontal relative displacement of the foundation and the superstructure supported by the foundation is allowed, the external load received by the superstructure causes the horizontal relative displacement of the foundation and the superstructure. reduces the load that is absorbed by and transmitted to the foundation.

For this reason, according to the vibration isolation structure of Patent Document 1, the effect of protecting the rising portion of the foundation can be expected, but the vibration isolation structure of Patent Document 1 imparts a vibration isolation function to the rising portion of the foundation itself, such as a continuous foundation. Neither does it improve the resistance to the lateral load (lateral pressure) of the foundation rising portion.

The connecting member employed in the vibration isolation structure of Patent Document 1 is formed by bending a steel bar. If the upper structure is a small building such as a wooden house, such a connecting member can stably hold the upper structure moving relative to the foundation when an external load is applied.

However, if the superstructure is a building such as a building or house made of a steel frame or a light steel frame with a large dead weight, the connection member disclosed in Patent Document 1 cannot stably hold the superstructure that is relatively displaced. Have difficulty. Therefore, the connection between the rising portion of the foundation and the foundation must be made through the anchor bolts planted in the rising portion of the foundation.

In connection via anchor bolts planted in the foundation rising portion, the external load received by the upper structure becomes a lateral load via the anchor bolt and is transmitted to the foundation rising portion.

However, the rising part of the foundation of raft foundation and continuous foundation is generally reinforced by embedding the main reinforcing bars and rising reinforcing bars in concrete, and the superstructure is made of steel and is heavy. It becomes difficult to ensure sufficient strength against vertical and lateral loads.

Since the thickness between the inner and outer sides of the foundation riser is restricted, it is difficult to take measures to improve strength such as embedding stirrups.

For this reason, it has been desired to increase the resistance to the vertical load and lateral load of the foundation rising portion by adopting a structure that is not subject to construction regulations.

An object of the present invention is to meet the above requirements by providing a vibration isolation damper capable of imparting a vibration isolation function to the foundation rising portion itself, and a base isolation structure for a building foundation using the damper.

In order to solve the above problems, the present invention provides a vibration isolation damper that is used by being embedded in the concrete of the foundation rising portion of a raft foundation or continuous foundation.

The damper for vibration isolation has a concave curved portion in the center in the longitudinal direction, and straight portions extending in the longitudinal direction on both sides of the concave curved portion. , a plurality of round steel spring steel bending rods connected via a reverse bending portion curved in a direction opposite to the bending direction of the concave curved portion;
and a restraining ring that restrains the movement of the plurality of bending rods,
The straight part of the bending rod has a male thread for screwing a nut on the outer periphery, and the plurality of bending rods are arranged vertically along the surface of the imaginary cylinder that is concavely curved and constricted in the central part. placed in the direction of
The restraint ring is loosely fitted near the middle of the concave curved portions of the plurality of bending rods along the surface of the virtual cylinder.

The present invention also provides a seismic isolation structure for a building foundation configured by arranging the seismic isolation damper at a foundation rising portion.

In the vibration isolation structure, the vibration isolation damper fixes one straight portion of a plurality of bending rods to a base installed on the rising portion of the foundation of the building with a nut screwed to the male screw, Furthermore, the straight portion on the other side of the several bending rods is fixed to the support plate at the upper end of the steel bundle embedded in the concrete of the rising portion of the foundation with a nut screwed to the male screw. It is interposed between the bundle and the base. A height-adjustable steel bundle is used.

Preferably, the vibration isolation damper is composed of an even number of bent rods, and the even number of bent rods are arranged at a constant pitch in the circumferential direction. If the number of bending rods combined is an even number, preferably two or four, lateral loads applied in opposite directions can be received in a well-balanced manner.

The vibration isolation structure of the building foundation is applied to the raised portion of the raft foundation and continuous foundation constructed through the following steps.

The inventor of the present application has previously proposed a method of constructing a raft foundation for supporting a building of lightweight steel structure as follows.

The construction method is to place a light-weight steel frame foundation on top of the discarded concrete formed at the site where the foundation is installed, supported by steel bundles that can be adjusted in height, and adjust the level of the foundation (leveling). By implementing the above before placing the reinforcing reinforcing bars for the foundation base and the foundation rising part and placing the concrete, it is possible to easily adjust the level of the foundation and to arrange the reinforcement reinforcing bars based on the position of the foundation. This is for simplification.

According to this method, the steel bundles supporting the foundation are embedded in the concrete of the foundation riser to be installed later, which also serves as reinforcement for the foundation riser.

In addition, on the foundation, before reinforcing the foundation bottom plate and the foundation rising part, the lower end side is bent and attached to the foundation as a hook. By engaging a part of the main reinforcement, the foundation riser and the base are firmly connected, and the synergistic effect of these makes it possible to construct a foundation with excellent support stability for the base.

In the seismic isolation structure of the present invention, the base is placed at the installation location by supporting the base with a steel bundle and the seismic isolation damper having the other end fixed to the support plate at the upper end of the steel bundle. Then, before pouring the concrete for the rising part of the foundation, the level of the foundation is adjusted, after that, the reinforcing bars of the foundation are arranged, the formwork for the rising part of the foundation is installed, and ready-mixed concrete is poured into the formwork. It is built through the processes of curing and solidifying the finished concrete and removing the formwork.

When the concrete is poured into the formwork, the damper for vibration isolation is surrounded by a filling material that prevents the ready-mixed concrete from flowing in, so that it is not buried in the concrete of the rising part of the foundation.

In addition, the formwork includes spacers several centimeters thick to be attached to the bottom surface of the base, and ready-mixed concrete is poured into the formwork to form the upper surface of the concrete at the base rising portion and the lower surface of the base. A gap corresponding to the thickness of the spacer is formed between them to allow elastic deformation of the vibration isolation damper.

If the spacer is made of expanded polystyrene or the like that can be compressed with a small load, the portion where the spacer remains without being removed is also regarded as the gap.

The method proposed earlier by the inventor of the present application is for constructing a raft foundation. As a result, a vibration isolation function can be imparted to the base rising portion.

In the vibration isolation damper of the present invention, a plurality of bending rods made of spring round steel act as reinforcing members and springs to increase resistance to vertical loads and horizontal loads (lateral loads, etc.) at the base rising portion.

The multiple bending rods are bundled by a ring that is loosely fitted in the middle part of the concave curved part. performance.

The bending rods act as stiffeners to increase the strength of the foundation riser against vertical and horizontal loads.

In addition, when a downward external load is applied to the upper structure on the foundation, the bending rod bends (results in elastic deformation) and absorbs the load. part is prevented from being damaged.

Even when horizontal vibration or horizontal load is applied to the rising portion of the foundation, the bending rod bends and absorbs the vibration and load, thereby attenuating the load transmitted to the rising portion of the foundation. It prevents you from taking big damage such as buckling.

1 is a perspective view showing an example of a vibration isolation damper of the present invention; FIG. FIG. 2 is a front view of the vibration isolation damper of FIG. 1; FIG. 2 is a plan view of the vibration isolation damper of FIG. 1; FIG. 4 is a front view showing another example of the vibration isolation damper of the present invention; FIG. 5 is a plan view of the vibration isolation damper of FIG. 4; FIG. 4 is a perspective view showing a state in which a foundation supported by a foundation is supported by a support that combines a steel bundle and the vibration isolation damper of the present invention; FIG. 4 is a view showing a connection state between a support comprising a steel bundle and the vibration isolation damper of the present invention and a base. 1 is a cross-sectional view showing a part of an example of a building foundation employing a vibration isolation damper of the present invention; FIG. Fig. 2 is a perspective view showing a state in which a formwork for a foundation rising portion is installed in a foundation installation portion of a building; FIG. 3 is a side view showing a part of the foundation rising portion of the raft foundation employing the vibration isolation damper of the present invention;

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a vibration isolation damper of the present invention and a vibration isolation structure for a building foundation using the damper will be described below with reference to FIGS. 1 to 10 of the accompanying drawings.

As shown in FIGS. 1 to 3, the exemplary vibration isolation damper 1 is composed of four bending rods 2 bent into the same shape and one restraining ring 3. As shown in FIGS.

The bending rod 2 is made of round steel spring steel. Each bending rod 2 has a concave curved portion 2a in the longitudinal center. In addition, straight portions 2b and 2c extending in the longitudinal direction are provided on both sides of the concave curved portion 2a, and the concave curved portion 2a and the straight portions 2b and 2c are opposite to the curved direction of the concave curved portion. It continues through the reverse bending part 2d curved in the direction.

The four bending rods 2 are arranged along the surface of an imaginary cylinder VC (see FIGS. 1 and 2. This imaginary cylinder VC is upright) having a concave curved constriction at the center. They are arranged vertically while maintaining a constant pitch.

The straight portions 2b and 2c of the bending rod 2 are processed with external threads 4 for screwing nuts on the outer periphery thereof.

The restraint ring 3 is loosely fitted in the intermediate portion of the concave curved portions 2a of the four bending rods 2 along the outer circumference of the virtual cylinder VC. When the vibration isolation damper 1 receives a vertical compressive load, the concave curved portions 2a of the bent rods 2 tend to move away from each other. The restraint ring 3 stops its movement and maintains the bundling state of the four bending rods 2 .

In the illustrated vibration isolation damper 1, the bending rod 2 is made of spring steel (SUP10) with a diameter of 16 mm, and the restraint ring 3 is made of round steel with a diameter of 12 mm. The restraining ring 3 need not be spring steel. Also, the restraint ring 3 may be made by slicing a thick steel pipe.

Both the inner bending radius R1 of the bending shown in FIG. 2 of the concave curved portion 2a of the bending rod 2 and the outer bending radius R2 of the bending of the reverse bent portion 2d are 50 mm, the inner diameter d1 of the restraint ring 3 is 48 mm, and the outer The diameter d2 is 72 mm, the diameter of the circle S (see FIG. 3) inscribed by the concave curved portion 2a of each bent rod 2 is 16 mm, the length L of the straight portions 2b and 2c of the bent rod 2 is 42 mm, and the adjacent bent rods 2 is designed to have a center-to-center distance W (also see FIG. 3) of 60 mm, and the height H of the vibration isolation damper 1 is designed to be 220 mm, but this is only an example.

The thickness of the spring steel forming the bending rod 2 and the thickness of the round steel forming the restraint ring 3 are also not limited to the illustrated dimensions.

The vibration isolation damper 1 configured in this manner has the straight portion 2b on one side of the base installed on the rising portion of the foundation, and the straight portion 2c on the other side on the discarded concrete of the foundation. It is used by fixing with a nut to the support plate at the upper end of the steel bundle embedded in concrete.

The vibration isolation damper 1 shown in FIGS. 4 and 5 is composed of two bent rods 2 and a restraint ring 3. As shown in FIG. Thus, the vibration isolation damper 1 using two bending rods 2 also exhibits the function of reinforcing the rising portion of the foundation and the function of damping the load and vibration applied to the rising portion of the foundation.

FIGS. 6 to 10 show an example of a vibration isolation structure for a building foundation constructed by embedding the vibration isolation damper 1 of FIG. 1 in the concrete of the foundation rising portion.

In the illustrated seismic isolation structure, the straight portions 2b on one side of the four bending rods 2 of the seismic isolation damper 1 are, as shown in FIG. It is fixed by a nut 14 screwed onto the male screw 4 to a base 13 installed on the portion 12 .

The base 13 is formed of a steel frame (H-shaped steel) such as a lightweight steel frame. As shown in FIGS. One end of the vibration isolation damper 1 is fixed to the base 13 by pinching the flange 13a of the base with a plurality of nuts 14 screwed onto the male threads 4 on the outer periphery of the straight portion 2b.

Further, the straight portion 2c on the other side of the four bending rods 2 is fixed to the support plate 15a at the upper end of the steel bundle 15 by a nut 14 screwed onto the male screw 4. It is interposed between 15 and base 13 .

A height-adjustable steel bundle 15 is used. This steel bundle 15 is embedded in the concrete 12a of the foundation rising portion 12. As shown in FIG.

The foundation of the building employing the exemplary seismic isolation structure is constructed in the following manner.

As shown in FIGS. 6 to 9, the construction method is to place a foundation 13 composed of combined steel frames (in the figure, it is made of lightweight steel) on top of discarded concrete 16 formed in the foundation installation section at the site. An adjustable steel bundle 15 and a vibration isolation damper 1 having the other end fixed to a support plate 15a at the upper end of the steel bundle 15 are arranged to be supported by a support.

Then, level adjustment (leveling) of the foundation 13 is performed before the reinforcing bars of the foundation base 11 and the foundation rising portion 12 and concrete placement are performed.

Before and after the level adjustment, it is possible to suspend and attach a reinforcing bar hook to the base 13 as an anchor. Since the portion 12 and the base 13 are connected via the vibration isolation damper 1, the reinforcing bar hook may be omitted.

After the level adjustment of the foundation 13 is finished, the reinforcing bars 17 for reinforcing the foundation shown in FIG. 8 are arranged. The reinforcing bars 17 for reinforcing the foundation shown in FIG. 8 are composed of reinforcing bars 17a for reinforcing the base plate of the mat foundation and reinforcing bars 17b for reinforcing the rising portion of the foundation.

The reinforcing bar 17b for reinforcing the base rising portion in FIG. 8 is a combination of a main reinforcing bar _17b1 with double bar arrangement, a stirrup bar 17b2 with _double bar arrangement, and a rising reinforcing bar _17b3 arranged on the extension of the reinforcing bar 17a for reinforcing the bottom panel. It has become a thing. If necessary, reinforcement of the base rising part is done by adding abdominal muscles.

After going through the above steps, as shown in FIG. The formwork 18 is supported using a pipe support jack 19 or the like, if necessary.

When installing this formwork 18, a filling material 20 (see FIG. 10. This may be a square tube made of polystyrene foam or the like) for blocking the inflow of ready-mixed concrete is fitted inside the formwork 18, and each damper 1 for vibration isolation is installed. is surrounded by the filler 20.

In addition, the mold 18 includes a plate-like spacer 21 (also see FIG. 10) having a thickness of several cm (preferably about 2 to 3 cm), which is attached to the lower surface of the base 13. This spacer 21 is a plate made of polystyrene foam. ) is included, and elastic deformation of the vibration isolation damper 1 is allowed between the upper surface of the concrete 12a of the foundation rising portion 12 and the lower surface of the base 13 that is put into the formwork 18 and formed. A gap G corresponding to the thickness of the spacer is formed.

After the installation of the formwork 18 is completed, ready-mixed concrete is poured into the inside of the formwork 1. - 特許庁Then, the poured concrete is cured and solidified for several days, and after going through the process, the formwork 18 is removed to complete a slab foundation having a foundation rising portion of the vibration isolation structure.

FIG. 10 shows a part of the side surface of the foundation rising portion 12 of the raft foundation constructed as described above.

As can be seen from the figure, the base 13 is supported by the raised foundation portion 12 via the damper 1 for vibration isolation, and a spacer 21 is provided between the base 13 and the upper end of the concrete 12a of the raised foundation portion 12 for vibration isolation. A gap G is created to allow elastic deformation of the damper 1 (displacement of the base 13 downward due to the elastic deformation).

Further, at the place where the vibration isolation damper 1 is installed, the concrete 12a of the foundation rising portion 12 is notched, and the vibration isolation damper 1 is exposed.

If the filler 20 surrounding the vibration isolation damper 1 is a member made of foamed polystyrene, rubber blocks, or the like that can be compressed with a small load, the filler 20 can be used for vibration isolation. Since it does not interfere with the elastic deformation of the damper 1, it may be left between the base 13 and the concrete 12a of the foundation rising portion 12 without being removed. It can be used as a vent.

If the spacer 21 included in the formwork 18 is also a plate made of expanded polystyrene or rubber that can be compressed with a small load, the spacer 21 hinders the elastic deformation of the vibration isolation damper 1. Therefore, it may be left between the base 13 and the upper end of the concrete of the foundation rising portion without removing it. The area where the spacer 21 is left is also considered as a substantial gap G in the present invention.

In addition, the reference numeral 22 in FIG. 8 is crushed stone that the ground E of the foundation installation portion is excavated to a predetermined depth and is put into the excavation portion, the reference numeral 23 is a moisture-proof sheet covering the crushed stone 22, and the reference numeral 24 is the moisture-proof sheet 23. Concrete sheet cover that was constructed.

1 Vibration isolation damper 2 Bending rod 2a Concave curved parts 2b, 2c Straight part 2d Reverse bending part 3 Constraint ring 4 External screw 11 Foundation bottom plate 12 Foundation rising part 12a Concrete 13 Base 13a Steel frame (H-shaped steel) flange 14 Nut 15 Steel Bundle 15a Upper end support plate 16 Scrap concrete 17 Foundation reinforcing bar 17a Bottom reinforcing bar 17b Foundation rising portion reinforcing reinforcing bar 17b ₁ Main bar 17b ₂ Stirrup bar 17b ₃ Rising reinforcing bar 18 Formwork 19 Support jack 20 Filler 21 Spacer 22 Crushed stone 23 Moisture-proof sheet 24 Sheet cover R1 Inner bending radius R2 of concave bending portion Outer bending radius of reverse bending portion d1 Inner diameter of restraining ring d2 Outer diameter of restraining ring S Concave bending portion of bending rod Inscribed circle L Length of straight part H Height of vibration isolation damper VC Imaginary column G constricted in the center G Gap created between concrete and foundation E Ground of foundation installation part

Claims (4)

It has a concave curved portion (2a) in the center in the longitudinal direction, and straight portions (2b, 2c) extending in the longitudinal direction on both sides of the concave curved portion (2a). 2a) and said straight portions (2b, 2c) are connected to each other via a reverse bent portion (2d) curved in the direction opposite to the curved direction of said concave curved portion (2a). a bending rod (2) made of
a restraining ring (3) that restrains the movement of the plurality of bending rods (2),
The straight portions (2b, 2c) of the bending rods (2) have external threads (4) for screwing a nut on the outer periphery, and the plurality of bending rods (2) are curved concavely at the central portion. It is arranged vertically along the outer periphery of a constricted upright virtual cylinder (VC),
A vibration isolation damper in which the restraining ring (3) is loosely fitted near the middle of the concave curved portions (2a) of the plurality of bending rods (2) along the outer circumference of the virtual cylinder (VC). . 2. A vibration isolation damper according to claim 1, wherein an even number of said bending rods (2) are combined, and said bending rods are arranged at a constant pitch in the circumferential direction. The vibration isolation damper (1) according to claim 1 or 2 is configured by a nut (14) screwing a male screw (4) to a straight portion (2b) on one side of the plurality of bending rods (2). It is fixed to the base (13) installed on the foundation rising part (12) of the building foundation, and the straight part (2c) on the other side of the several bending rods (2) is screwed to the male screw (4). The height-adjustable steel bundle (15) embedded in the concrete (12a) of the foundation riser (12) is fixed to the support plate (15a) at the upper end of the base riser (12) with the nut (14). Interposed between the steel bundle (15) and the base (13),
The damper for vibration isolation (1) is installed in the concrete (12a) of the foundation rising portion (12).
is not embedded against
Seismic isolation of a building foundation in which a gap (G) that allows elastic deformation of the vibration isolation damper (1) is created between the concrete (12a) of the foundation rising portion (12) and the base (13). structure. 4. The seismic isolation structure of the building foundation according to claim 3, wherein the building foundation is a mat foundation or continuous foundation.

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