JP3811711B2 - Building seismic isolation structure - Google Patents

Description

  The present invention relates to a seismic isolation structure for a building such as a condominium or an office building. In particular, it relates to a seismic isolation structure for buildings that can control foundation construction costs at a relatively low cost. The present invention also relates to a seismic isolation structure for a building that can improve the maintainability of the seismic isolation device and the utilization of space in the building.

  A number of various structures and systems have been filed as conventional seismic isolation structures having seismic isolation support means between the foundation such as the ground and the building structure (for example, Patent Document 1, Patents). Literature 2, Patent Literature 3). As the seismic isolation bearing means used, there are a laminated rubber mold having a restoring force and a sliding / oscillating (rotating) sliding bearing mold.

  When a horizontal force (horizontal force) is applied between the building and the foundation during an earthquake, the laminated rubber-type seismic isolation means deforms in that direction and returns to its original shape when the force is released. Has properties. In this type of seismic isolation means, horizontal force acts on the pile head, so an underground beam (or a connecting structure having considerable rigidity) that connects the pile heads of adjacent foundation piles is required. Such underground beams are provided between the foundation footings by providing foundation footings on the pile heads.

On the other hand, as a rotary type (with a rotation mechanism) sliding support type seismic isolation means, one having a pin-supporting sliding mechanism is disclosed (for example, see Patent Document 4). The mechanism has upper and lower bonding members and a pin bonding portion that connects both the bonding members. And the slip board is arrange | positioned on the upper surface of an upper joining member, and the slip board which contacts this slip board is attached to the bottom face of a structure.
In this seismic isolation means, even if the foundation pile is inclined, the contact surface between the sliding plate of the upper joint and the sliding plate of the structure is maintained almost horizontal, so that the structure moves while maintaining the horizontal posture. For this reason, in principle, no horizontal force is applied between the foundation pile and the building, and the load on the pile head is small, so there is no need for underground beams to connect the pile heads of the foundation pile.
Furthermore, there is an advantage that the thickness (height) is thin as compared with the laminated rubber type seismic isolation means.

  Patent Document 1 proposes a combination of a sliding bearing and a restoring rubber (laminated rubber) as a seismic isolation bearing means. Specifically, slip-support type seismic isolation means are installed at the four corners of the building base and the lower part of the doorway, and restoration rubber-type seismic isolation means are installed at at least two of the four corners of the foundation. I am going to do it. And the material characteristic of restoration rubber is specified and the stability of seismic isolation performance is aimed at.

Patent Document 2 discloses a structure in which a seismic isolation shoe is interposed between a pillar driven into the ground and a pillar forming the skeleton of a building structure. As the seismic isolation shoe, a laminated integrated structure (laminated rubber type) of an elastic rubber body and a steel plate having a configuration capable of shifting in the lateral direction is used. Patent Document 3 discloses a structure in which a seismic isolation device is interposed between a lower end portion of a steel column and a foundation placed on an upper portion of a steel pipe pile driven into the ground. As the seismic isolation device, a laminated rubber type or sliding support type seismic isolation support means is used.
However, in these documents 2 and 3, the same kind of seismic isolation means is arranged in one building. In addition, there is no mention of how to install seismic isolation means on the foundation of the building.

Incidentally, the laminated rubber type seismic isolation means has the following problems.
In the case of the laminated rubber mold, as described above, an underground beam connecting adjacent pile heads is required. Providing such underground beams generally requires deep excavation of the ground, which requires cost and time for excavation work. Furthermore, since the thickness of the base isolation support means is relatively thick (high), in order to place the base isolation pile support means at the pile head of the foundation pile so that the first floor of the building is located almost at the ground level, It is necessary to deepen the excavation depth by the seismic isolation support means. On the other hand, when the seismic isolation support means is positioned at the ground level, the excavation depth is relatively shallow, but the height of the first floor is increased by the thickness of the seismic isolation support means and the thickness of the floor structure. This height is, for example, at least about 2000 mm from the ground level, which hinders the use of the building.

  On the other hand, in the case of the sliding support type with a rotation mechanism, it is not necessary to provide an underground beam for connecting the pile heads, so that the construction work can be simplified.

JP 2003-301625 A JP-A-6-136990 JP-A-9-256667 Japanese Patent Laid-Open No. 2004-44312

  An object of the present invention is to provide a seismic isolation structure for a building that can suppress the foundation construction cost relatively inexpensively by taking advantage of the above-described sliding support type seismic isolation support means with a rotating mechanism. Moreover, it aims at providing the seismic isolation structure of a building which can improve the maintainability of a seismic isolation apparatus, and the utilization of the space in a building.

The seismic isolation structure of a building related to the present invention is a seismic isolation structure that supports a building via a plurality of seismic isolation support means distributed on a foundation, and is installed in a corner portion of the building. The bearing means is a restoring bearing means having a restoring force, and the seismic isolation bearing means arranged in the central part of the building is a sliding bearing means with a rotating mechanism that does not have a restoring force. It is characterized by having rigidity to withstand lateral loads, and the foundation of the central portion has low rigidity.

  With such a structure, in the event of an earthquake, horizontal force and bending moment (a combination of both are referred to as lateral load) are applied to the foundation of the corner of the building, but lateral load is applied to the foundation of the center of the building. It hardly takes. In addition, the horizontal force necessary to displace each foundation pile at the same time during an earthquake is applied to the central foundation piles via soil concrete, etc., but this force is used to shake the building horizontally. It is much smaller than the force applied between the foundation of the corner of the building and the building.

  Therefore, the foundations at the four corners of the building may be rigid enough to withstand lateral loads, and the foundation at the central part may be low in rigidity. Therefore, it is only necessary to provide underground beams that connect foundation footings and pile heads only at the periphery of the corners of the building. As a result, the amount of ground excavation and excavation work time for installing the underground beam and the foundation footing can be reduced, and the construction work cost and material cost of the foundation structure can be reduced.

In the above invention, the restoration support means at the corner is disposed on a foundation footing or an underground beam connected to the foundation pile, and the sliding support means at the center is disposed at the pile head of the foundation pile. The space between the majority of the foundation piles in the center can be considered as a low rigidity foundation.

The low-rigidity foundation can simplify the construction work compared to the rigid foundation. For this reason, the cost of the entire construction work can be reduced by using a low-rigidity foundation between the majority of foundation piles. As the low-rigidity foundation, for example, a soil slab having a thickness of about 200 mm can be used.
In addition, the foundation footing and the underground beam are not clearly distinguished, and the foundation footing and the underground beam may be integrated and extend between the foundation piles.

  As a specific aspect of the present invention, the building is substantially rectangular in a plan view, and the foundation of the building is formed by hitting foundation piles at four corners of the building and at some points between the corners. The restoration support means are arranged at the four corners of the building, and the slide support means are arranged at a certain interval between the corners in the longitudinal direction of the building (center portion). On the side (short side) of the building, underground beams are provided. On the side (long side) in the longitudinal direction of the building, the corner is placed between the corner foundation pile and the foundation pile adjacent in the longitudinal direction. An underground beam with a lower beam back (beam height) is provided from the foundation pile to the adjacent foundation pile, and an underground beam is provided in the center of the long side to connect the adjacent foundation piles. Can not be.

In the present invention, the restoration support means at the corners and the sliding support means at the center are arranged on a concrete placement body that is directly arranged and distributed, and the majority of the center part. It can be assumed that a low-rigidity foundation is provided between the cast bodies.
If the ground is solid, a concrete foundation that is a foundation may be arranged directly instead of the foundation pile. In this case, it is not necessary to hit the foundation pile, so that the work for constructing the foundation can be simplified.

  As another specific aspect of the present invention, the building is substantially rectangular in a plan view, and the foundation of the building hits a concrete placing body that is a foundation directly at the four corners of the building and at some points between the corners. The restoration support means are arranged at the four corners of the building, and the slide support means are arranged at a certain interval between the corners in the longitudinal direction of the building (central part). It can be assumed that there are no underground beams connecting the adjacent direct foundations.

In the present invention, in the central part of the long side of the building, it is preferable that a beam having relatively high rigidity that receives a bending moment generated in the building by a horizontal force at the time of an earthquake is provided on the bottom floor. .
In the central part of the long side of the building, since the foundation is a low-rigidity foundation and seismic isolation means with a rotation mechanism is provided between the building and the foundation, a lateral load is applied to the beam on the bottom floor of the building during an earthquake. It takes. Therefore, by providing a beam having rigidity higher than that of the beam of the lowermost floor in the case of using normal seismic isolation support means (for example, laminated rubber type seismic isolation support means) on the lowermost floor, The rigidity of the entire building can be secured. This point will be specifically described later with reference to FIG.

In this invention, it is preferable that each said seismic isolation bearing means is arrange | positioned at the substantially ground level.
Since the seismic isolation support means is arranged almost at the ground level, it is not necessary to bury the means in the ground, and the amount of ground excavation can be reduced. In addition, the inspection and replacement of the seismic isolation support means can be performed relatively easily.

  In the present invention, the lowermost floor of the building has a relatively high height so that a space between the lowermost floor and the ground level can be used, and the floor structure of the lowermost floor extends in one direction. The main beam extends downward from the floor, and the main beam extending in the other direction can extend upward from the floor (reverse beam).

  If the seismic isolation support means is almost at the ground level, the height of the bottom floor of the building will be increased by the sum of the thickness of the means and the bottom beam. Therefore, this height is set as a desired dimension, and the space between the bottom floor and the ground is effectively used. For example, when the height of the bottom floor is about 1800 mm, it can be used as a parking space. And even in the area where the height of the building is limited by the shadow regulation, even when the first floor is a parking space and the building is a four-story building, the height of the entire building can be suppressed to 10 m or less.

  However, when it is used as a parking lot space, if the lowermost beam protrudes downward, the height of the beam is 1800 mm minus the height of the beam, and the vehicle collides. Therefore, in the direction orthogonal to the main entrance / exit direction of the vehicle (for example, the short side direction of the building), the lowermost beam is used as an inverted beam protruding upward from the floor so as not to obstruct the entrance / exit of the vehicle.

  In the present invention, the height of the bottom floor of the building can be about 1400 mm or less from the ground level. In other words, the height of the bottom floor is the sum of the height of the base isolation support means and the height of the bottom floor structure, but by using a thin base isolation support means, The height of the first floor can be lowered even when the support means is almost at the ground level. If the height of the first floor is about 400 mm, this step can be eliminated by using a slope or the like to the extent that there is no practical problem. Moreover, the amount of ground excavation can be reduced as much as possible.

Another seismic isolation structure related to the present invention is a seismic isolation structure that supports a building via a plurality of seismic isolation support means distributed on a foundation, and each of the seismic isolation support means is substantially at ground level. The main beam extending in one direction of the bottom floor structure of the building is projected downward from the floor, and the main beam extending in the other direction is upward from the floor. It is characterized by being overhanging (reverse beam).

  When the seismic isolation support means is arranged on the ground level, the height of the first floor of the building is inevitably high. Therefore, this height is used as a desired height, and the space between the first floor and the ground level is used as a parking lot or a storage. At this time, the beam on the first floor extending in the direction orthogonal to the direction of entry / exit of the vehicle is a reverse beam so that the beam does not prevent entry / exit of the vehicle.

Another seismic isolation structure related to the present invention is a seismic isolation structure that supports a building via a plurality of seismic isolation support means distributed on a foundation, and each of the seismic isolation support means is substantially at ground level. The floor of the lowermost floor of the building is provided with an underfloor space, the height of the floor of the lowermost floor of the building is about 1400 mm, and the entrance to the space is provided using the underfloor space as a maintenance space. You can also.

Another seismic isolation structure related to the present invention is a seismic isolation structure that supports a building via a plurality of seismic isolation support means distributed on a foundation, and each of the seismic isolation support means is substantially at ground level. It is possible to form another floor surface below one floor of the lowermost floor of the building, and the other floor surface may be on the ground level.

  In the building of the present invention, the height of the first floor is inevitably high, so that the underfloor space can be provided by using the height. If the floor height of the underfloor space is equal to or higher than the ground level, it is possible to prevent dew condensation in the building without hindering ventilation under the floor.

Another seismic isolation structure related to the present invention is a seismic isolation structure that supports a building via a plurality of seismic isolation support means distributed on a foundation, wherein the plurality of seismic isolation support means are restored. In the part where the adjacent support means is the restoration support means, the restoration support means having the force and the sliding support means with the rotation mechanism not having the restoration force are provided at the base portion between the two support means. In the part where the underground beam is provided and the adjacent support means is the sliding support means, the underground beam is not provided in the base portion between the two support means, and the adjacent support means is restored. In the part which is the support means and the slide support means, the beam back (the height of the beam) is formed on the foundation part between the two support means from the foundation under the restoration support means toward the foundation part under the slide support means. Underground beams that are low) are provided And it features.

  By setting it as such a structure, the space of the location which installs an underground beam and an underground beam can be reduced as much as possible.

  In the present invention, the building is substantially rectangular in a plan view, and the restoration support means is arranged at the four corners of the building and the central part of the side in the short direction, and the longitudinal side of the building is The sliding support means can be arranged in the central portion.

  If the size of the building is relatively large and the specified restoring force cannot be obtained by using only the four corners of the restoration support means, the restoration support means is also arranged in the center in the short direction and the seismic isolation function of the entire building is adjusted Shall be able to.

In the present invention, the surface of the portion of the foundation where the underground beam between the adjacent sliding support means is not provided is soil concrete, and at least a part of the underground beam has substantially the same thickness as the soil concrete. is a is, you shall amount and structure of internal reinforcement is strengthened.

  By adopting such a structure, it is possible to handle the moment applied to the restoration support means on the basis while making the beam back (height) of the underground beam as low as possible. Soil concrete refers to a concrete floor whose bottom surface is in direct contact with the soil (also referred to as a soil slab), and is strong enough to withstand standard loads on which people work and place objects. Have. By setting the thickness of the underground beam to the same level as the soil concrete, the amount of ground excavation for installing the underground beam can be reduced. In addition, since the thickness of the part of the underground beam and the concrete between the soils is equal, the shape of the cast concrete can be made into a substantially flat and simple shape, and the labor for the formwork and the like can be reduced.

  As is apparent from the above description, according to the present invention, it is possible to provide a seismic isolation structure for a building that can suppress foundation construction costs relatively inexpensively. Furthermore, it is possible to provide a building seismic isolation structure that can improve the maintainability of the seismic isolation device and the utilization of the space in the building.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram for explaining a seismic isolation structure for a building according to an embodiment of the present invention. FIG. 1 (A) is a plan view showing an arrangement state and a basic structure of seismic isolation means, and FIG. These are sectional drawings of a foundation structure and the 1st floor part of a building.
FIG. 2 is a diagram for explaining an example of the structure of the restoration support means that is the seismic isolation support means.
FIG. 3 is a diagram for explaining an example of the structure of the sliding support means with a rotation mechanism, which is a seismic isolation support means.
As shown in FIG. 1 (A), the building foundation 10 is a horizontally long, substantially square shape in a plan view. As shown in FIG. 1 (B), the building 1 is supported on the foundation structure 10 via seismic isolation support means 20 and 30. Moreover, the circumference | surroundings of the foundation structure 10 are covered with the outer peripheral wall 70 (refer FIG. 1 (B)).

  The foundation structure 10 has foundation piles 11 driven into the ground between the four corners of the building 1. In this example, four places (symbol 11a) at the corner of the building 1 and three places (symbol 11b) located at equal intervals between the longitudinal corners of the building 1 shown in the upper side of FIG. A total of ten foundation piles 11 are struck in three places (reference numeral 11b) located at equal intervals between the corners in the longitudinal direction shown in the lower side of FIG.

The seismic isolation support means is arranged between the pile head of the foundation pile 11 and the structure (main column) 2 of the building 1. The means includes a restoring bearing 20 having a restoring force and a sliding bearing 30 with a rotating mechanism having no restoring force.
The restoration bearings 20 are arranged on the pile heads (foundation footings 12, which will be described later in detail) of the foundation piles 11 a provided at the four corners of the building 1. On the other hand, the sliding bearing 30 with the rotation mechanism is disposed on the pile head of the foundation pile 11b provided in the central portion (a portion between the four corners) of the building 1. Further, as will be described in detail later, all the seismic isolation bearing means 20 and 30 are provided substantially at the ground level (GL).

  Foundation footings 12 are provided on the pile heads at the foundation piles 11a at the four corners of the building. The foundation footing 12 is a concrete block integrated with the pile to reinforce the pile head. The foundation footing 12 is embedded in the ground.

  As shown in FIG. 1 (A), the foundation footings 12 of the foundation piles 11a adjacent to each other in the short direction of the building among the foundation piles 11a at the four corners are connected by underground beams 13A that are rigid foundation beams. Has been. Further, the foundation pile 11a at the four corners and the foundation pile 11b adjacent in the longitudinal direction are also connected by an underground beam 13B which is a rigid foundation beam. However, as shown in FIG. 1 (B), the underground beam 13B is laterally extended from the foundation footing 12 of the corner foundation pile 11a toward the foundation pile 11b next to the middle between the foundation piles 11a-11b. The beam back (the height of the beam) is lowered while gradually tilting upward toward the ground level GL.

  Moreover, the pile heads of all the foundation piles 11 are pressed and fixed by the soil slab 15 laid on the ground. The soil slab 15 disperses the horizontal force to the pile head and causes the pile head to be displaced at the same time during an earthquake. As shown in FIG. 1 (B), the soil slab 15 has a constant thickness (about 200 mm in one example) along the underground beam 13B extending in the ground at the portion of the foundation pile 11a at both ends in the longitudinal direction of the building. It is laid. And in the part of the foundation pile 11b of the center part of a building, it is a fixed thickness (for example, about 200 mm) along the ground level.

  Since the restoration support means 20 is provided in the foundation pile 11a at the four corners of the building, bending stress (moment) is applied to the pile head during an earthquake. For this reason, the foundation piles 11a at the four corners are provided with underground beams 13A and 13B having rigidity. On the other hand, the foundation pile 11b at the center of the building is provided with the sliding support means 30 with a rotation mechanism that does not apply bending stress to the pile head, and therefore no beam for receiving this bending stress is provided (low rigidity foundation). ).

Next, the structure of the seismic isolation support means will be described.
The restoring bearing 20 shown in FIG. 2 has the property of deforming in the direction when a horizontal force is applied and returning to its original shape when the force is released. The support 20 is composed of a laminated rubber body 27 including upper and lower mounting plates 21 and 22 and an elastic body 24 such as a rubber plate and a rigid body 25 such as a steel plate, which are sandwiched between them. A rubber type is used. The upper mounting plate 21 is fixed to the lower surface of the base 3 provided at the lower end of the pillar 2 of the building, and the lower mounting plate 22 is fixed to the upper end surface of the foundation footing 12 provided at the pile head of the foundation pile 11a. .
In addition to the one shown in FIG. 2, any restoration bearing 20 may be used as long as it has the same performance.

  On the other hand, as the sliding bearing 30 with a rotation mechanism, what is called a BSL pile head seismic isolation method (Basho-uti pile Slider) as shown in FIG. 3 can be used. The sliding bearing 30 with a rotating mechanism includes a sliding receiving member 31 and a slider 41. The slip receiving material 31 is fixed to the lower surface of the base 3 provided at the lower end of the pillar 2 of the building. The slider 41 is fixed to the upper end surface of the foundation pile 11b.

  The slip receiving member 31 has a slip plate 32 made of a stainless steel plate or the like whose surface is coated with fluorine. The slip plate 32 is fixed to the lower surface of the pedestal 3 via the back plate 33 with anchor bolts 34.

  The slider 41 has a concave member 42 embedded and fixed in a pile head of the foundation pile 11b, and a convex member 43 fitted into the concave member 42. The convex member 43 has a convex portion 43a projecting downward, and a slip plate 44 made of a fluorine-coated stainless steel plate or the like is attached to the upper surface. In a normal state, the slip plate 44 and the slip plate 32 of the slip receiving member 31 are in contact with each other on a horizontal plane. A recess 42 a is formed on the upper surface of the recess 42. The center of the tip of the convex portion 43a of the convex member is in contact with the center of the bottom of the concave portion 42a of the concave member. Moreover, the bending diameter of the convex part 43a of a convex member is smaller than the bending diameter of the concave part 42a of a recessed part material. For this reason, a clearance is formed between the convex portion 43a and the concave portion 42a. The clearance is filled with a filling material 45 that can be deformed in compression and can be restored.

  With such a structure, the convex member 43 and the concave member 42 move like a ball joint, and the convex member 43 can rotate relative to the concave member 42. In other words, when the foundation pile 11 b is inclined due to the earthquake, the recessed member 42 provided on the foundation pile 11 b swings and rotates with respect to the protruding member 43. At this time, the clearance between the convex portion 43 a of the convex member and the concave portion 42 a of the concave member changes, but the displacement is absorbed by the filler 45 and is not transmitted to the convex member 43. Therefore, the contact surface of the slide plate 44 of the convex member 43 and the slide plate 32 of the slide receiving member 31 fixed to the pillar 2 of the building is substantially maintained in a normal horizontal state. That is, the building is kept almost horizontal.

  In this sliding bearing 30 with a rotation mechanism, the sliding support member 31 can slide in the horizontal direction with respect to the slider 41, that is, the column 2 can slide in the horizontal direction with respect to the foundation pile 11b, so that the lateral load is reduced. There is an advantage that it does not act on the pile head. Further, as can be seen from the figure, it is also advantageous that the thickness is considerably thinner than the laminated rubber type restoration support 20 (in an example, the distance between the base and the foundation pile is about 100 mm).

As shown in FIG. 1B, these seismic isolation bearing means 20 and 30 are disposed substantially at the ground level GL.
The sliding support 30 with the rotation mechanism having a relatively thin thickness is entirely disposed on the ground level GL. That is, the upper end of the foundation pile 11b provided with the sliding bearing 30 with the rotation mechanism protrudes slightly upward from the soil slab 15 (ground level GL). And the sliding bearing 30 with a rotation mechanism is installed in the upper end surface.

Since the restoration bearing 20 is thicker than the sliding bearing 30 with the rotation mechanism, the height of the upper surface of the restoration bearing 20 and the upper surface of the sliding bearing 30 with the rotation mechanism are set to the same horizontal plane in order to match the height of the base 3 of the column 2. Together, almost half of the restoration bearing 20 is buried in the ground. For this reason, the foundation footing 12 and the underground beams 13A and 13B of the foundation pile 11a on which the restoration support 20 is installed are buried in the ground. However, since the entire restoration support 20 is not buried in the ground, the ground excavation depth for embedding them can be made relatively small. In this example, there are four restoration supports 20 and only six underground beams 13A and 13B. Therefore, the amount of ground excavation and excavation work time for embedding them can be reduced.
In addition, in the periphery of the foundation pile 11a at the four corners of the building, the soil slab 15 is dug slightly from the ground level GL, and the seismic isolation pit 61 is formed.

  Thus, the ground excavation work can be simplified by arranging the seismic isolation bearing means 20 and 30 substantially at the ground level GL. Furthermore, by such arrangement, as described above, the height of the first floor of the building 1 becomes high, but by using the sliding bearing 30 with a thin rotating mechanism as a seismic isolation bearing means, As will be described in detail below, the height of the first floor (1FL) can be made as low as possible.

  The first floor 5 is provided on a beam 7 spanned between the bases 3 of the pillars 2 adjacent to each other in the longitudinal direction and the short direction of the building 1. The beam 7 has a shape projecting downward from the first floor 5. As described above, since all the seismic isolation bearing means 20 and 30 are substantially at the ground level GL, the first floor 5 is positioned above the ground level GL as shown in the figure. However, the height is about the sum of the thickness of the sliding bearing 30 with the rotation mechanism and the thickness of the first floor beam 7. As described above, the thickness of the restoring bearing 20 and the thickness of the first floor beam 7 are the same. The height can be considerably lower than the height (2000 mm in one example). In this example, the height 1FL of the first floor 5 can be set to a height of 1400 mm from the ground level GL.

The first floor beam 7 has a rigidity higher than that of the first floor beam when a normal seismic isolation support means (for example, a laminated rubber mold) is used. This point will be described with reference to FIG.
FIG. 7 is a diagram for explaining moments acting during an earthquake. FIG. 7A shows a case where a normal seismic isolation support means (laminated rubber type) is used, and FIG. When the bearing is used, FIG. 7C is a moment diagram of both.
In the event of an earthquake, if a vibration is transmitted from the ground, that is, the foundation pile P side, to the building ST side, the massive building ST remains in its original position due to inertia. Then, an eccentric load is generated between the building ST and the foundation pile P, and a moment is applied between them.

As shown in FIG. 7 (A), when the laminated rubber-type seismic isolation means Q1 is provided, during an earthquake, a moment is applied to the upper first floor beam B1 and the lower underground beam BG. . That is, the moment M1 is applied to the underground beam BG below the means Q1, and the moment M2 is applied to the first floor beam B1 above the means Q1. Moments M1 and M2 act in the same direction as shown in the upper diagram of FIG. 7C, and are almost half of the moment applied during an earthquake.
More specifically, the moment M1 applied to the underground floor beam BG is 1/2 of the product of W1 (load received from the building ST) and L (displacement, see the lower diagram in FIG. 7B), and W2 ( It is represented by the sum of products of the horizontal force generated in the seismic isolation support means Q1 and H2 (height from the cross-section core of the underground beam BG to the cross-section core of the seismic isolation support means Q1). On the other hand, the moment M2 applied to the first floor beam B1 is 1/2 of the product of W1 (load received from the building ST) and L (displacement, see the lower figure in FIG. 7B) and W2 (seismic isolation bearing). It is represented by the sum of the products of the horizontal force applied to the means Q1 and H1 (height from the cross-sectional core of the seismic isolation support means Q1 to the cross-sectional core of the first floor beam B1).

On the other hand, when a sliding support Q2 with a rotating mechanism is provided as shown in the upper diagram of FIG. 7B, during an earthquake, as shown in the lower diagram of FIG. No moment is applied to the foundation pile P, and the moment M3 is applied only to the first floor beam B1 above the means Q2. Here, the moment M3 is the entire moment applied during an earthquake, as shown in the lower diagram of FIG. This moment M3 is the product of W1 (load received from building ST) and L (displacement), W3 (horizontal force applied to seismic isolation means Q2) and H (first pile from foundation pile P (slab S)) (The height to the cross-section core of B1).
Therefore, the rigidity of the first-story beam B1 (symbol 7 in FIG. 1) is increased as compared with the case of using a normal seismic isolation means (for example, a laminated rubber type seismic isolation means) (in one example, the section coefficient is doubled). Degree), the rigidity of the entire building can be secured.

As described above, the building 1 is supported on the foundation structure 10 via the seismic isolation support means 20 and 30, and the foundation piles 11 are fixed to the rigid foundation beams (underground beams) 13A and 13B or low rigidity. By connecting with the foundation beam (soil slab) 15, it acts as follows during an earthquake.
During an earthquake, only the foundation pile 11a at the four corners of the building is subjected to a bending moment in the horizontal direction on the pile head, and the foundation foundation pile 11b in the center has a structure that does not apply a bending moment due to horizontal force to the pile head. . For example, when the above-described sliding bearing 30 with a rotation mechanism is used as all the seismic isolation bearing means, the sliding movement in the lateral direction of the building 1 is limited and restored to the original position only by the means. There is no good work. Therefore, by providing laminated rubber type seismic isolation bearing means 20 having restoring force at the four corners of the building 1, the restoring force to the original position is provided.

  Furthermore, the height of the first floor 5 can be made as low as possible (about 1400 mm), although the seismic isolation means 20 and 30 are provided almost at the ground level GL. If the height of the first floor is about 1400 mm, this step can be eliminated by using a slope or the like to the extent that there is no practical problem.

Next, an example of a building using this seismic isolation structure will be described.
4-6 is a figure explaining the example of the building provided with the seismic isolation structure of this invention.
The building shown in FIG. 4 uses a space between the ground level GL and the first floor as a maintenance space.
In this building, an entrance / exit 71 to the maintenance space is provided at an appropriate position on the outer peripheral wall 70 so that the inspector can easily enter and exit the maintenance space. In this case, since each of the seismic isolation support means 20 and 30 is substantially at the ground level GL, the seismic isolation support means 20 and 30 can be easily inspected and replaced. Further, if the piping facilities P are collected in this maintenance space, the inspection and maintenance of these piping facilities P can be performed efficiently.

The building shown in FIG. 5 uses the space between the ground level GL and the first floor as the under-floor space of the house.
In this building, a floor is formed below the first floor 5 and a space 80 between the floor and the first floor 5 is used as an underfloor space. This underfloor space 80 can be used as, for example, a living room or a storage space. In this case, since the floor surface of the space 80 can be above the ground level GL, the ventilation under the floor of the entire building is not hindered.

The building shown in FIG. 6 uses the space between the ground level GL and the bottom floor as a parking space.
In this building, the ground level GL is the first floor, the lowest floor 5 is the second floor, and the first floor is used as a parking lot. Here, by setting the height of the lowermost floor 5 to about 1800 mm, it is possible to easily take in and out the car on the first floor. Furthermore, the height of the entire building can be suppressed to 10 m or less even in a four-story building with the first floor as a parking space in an area where the height of the building is restricted by the shadow regulations.

  Furthermore, since the lowest floor 5 is raised, all the seismic isolation bearing means 20, 30 can be arranged on the ground level GL. For this reason, only the portions of the foundation footing 12 provided in the four corner foundation piles 11a and the underground beams 13A and 13B (see FIG. 1) need to excavate the ground greatly.

  Furthermore, the beam 7 at the lowest level (second floor) is set as beams 7a and 7b projecting downward in the direction of entering and exiting the vehicle (in this example, the longitudinal direction of the building), and in the direction orthogonal to the same direction (in this example) In the short direction of the building), beams (reverse beams) 7A and 7B project upward. In other words, even if the bottom floor 5 is about 1800 mm in height, if a beam that projects downward is provided, the height of the first floor will be lowered by the amount of this beam, and cars and people will hit the beam. An unexpected situation occurs. Therefore, the vehicle can be smoothly taken in and out by setting the reverse beams 7A and 7B in the direction orthogonal to the main direction in which the car and people enter and exit.

FIG. 8 is a diagram for explaining a seismic isolation structure for a building according to another embodiment of the present invention.
In this example, as a foundation structure of the building, a foundation 90 is directly struck on the ground between the four corners of the building 1 instead of the foundation pile 11 shown in FIG.

In this example, the direct foundation 90 is constituted by a foundation footing 12 that is solidified with a split stone 93 and placed on a discarded concrete 91 (50 to 100 mm).
When the ground on which the building is installed is solid, it is not necessary to hit the foundation pile 11 deep into the ground, and such a direct foundation may be provided.

FIG. 9 is a plan view showing an arrangement state of the seismic isolation means and a part of the foundation structure in the seismic isolation structure for a building according to another embodiment of the present invention.
FIG. 10 is a side view showing a short side of the building of FIG.
FIG. 11 is a bar arrangement diagram of a pile head on the short side of the building of FIG. 9.
12 is a side cross-sectional view in the short direction of the center of the building in FIG.
FIG. 13 is a bar arrangement diagram of a pile head at the center in the longitudinal direction of the building of FIG. 9.
FIG. 14 is a side view showing the longitudinal direction of the building of FIG.
FIG. 15 is a partially enlarged view of FIG.

Also in this example, the building 101 (see FIGS. 10, 12, and 14) is supported on the foundation structure 110 via the seismic isolation support means 20 and 30. However, in this example, each seismic isolation support means is provided in the depth below the ground level GL. The seismic isolation bearing means includes two types of a restoration bearing 20 having a restoring force and a sliding bearing 30 having no restoring force. As shown in FIG. 10, the restoration bearing 20 is disposed on the foundation piles 11 a at the four corners of the building 101 and the central part of the short side (two places in this example). The sliding bearing 30 is arrange | positioned on the foundation pile 11b of the center part of the longitudinal direction of the building 101, as shown in FIG.12 and FIG.14. As the restoration support 20, a laminated rubber type restoration support as shown in FIG. 2 can be used. Moreover, what is called a BSL pile head seismic isolation method as shown in FIG. 3 can be used for the sliding bearing 30. FIG.
In addition, the code | symbol similar to FIG. 1 is attached | subjected to the site | part which has the effect | action and structure similar to the building of FIG. 1, and description is abbreviate | omitted.

As shown in FIG. 10, in the short side (including the four corners) of the building 101, the foundation footing 12 is provided on the pile head of the foundation pile 11 a, and the restoration support 20 is arranged on the upper surface of the foundation footing 12. . The foundation footing 12 has a rectangular parallelepiped shape with a depth of 2000 mm from the ground level GL, a length of one side of 2800 mm, and a thickness (height) of 400 mm around the pile head of the foundation pile 11a. Are placed at 150 mm pitch in the X and Y directions, and concrete (Fc = 30 N / mm ² ) is placed. As shown in FIG. 11, a restoration bearing installation surface 12a (height 100 mm) that is one step higher than the surface of the foundation pile 11a on the upper surface of the foundation footing 12 is formed.

As shown in FIG. 10, the foundation footings 12 on the short side are connected by underground beams 13A. The underground beam 13A is formed by placing concrete reinforcement (Fc = 30 N / mm ² ) between the foundation footings 12 by reinforcing a reinforcing bar having a diameter of 16 mm at a pitch of 150 mm in the X and Y directions. Although the upper surface of the underground beam 13A is the same surface as the foundation footing 12 (depth of 2000 mm from the ground level GL), the thickness is as thin as 200 mm. At the connecting portion between the underground beam 13A and the foundation footing 12, the lower surface of the underground beam 13A is inclined downward toward the lower surface of the foundation footing 12.

With reference to FIG. 11, the part of the pile head of the short side of a building is further demonstrated.
As shown in FIG. 11, upper and lower reinforcing bars (diameter: 16 mm) 131, 132 extending in the short direction (Y direction) through the underground beam 13A (see FIG. 10, the underground beam 13B in FIG. 15 has the same structure). Pass through each foundation footing 12. By having such a structure, the function of smoothly transmitting a force such as a bending moment from the foundation footing 12 to the adjacent foundation footing 12 or from the foundation footing 12 to the foundation pile 11a, although the thickness is relatively thin. The characteristics of the underground beam having the are given to the underground beam 13A.
Further, a π-shaped reinforcing bar (diameter 16 mm) 133 is arranged on the restoration support installation surface 12a of the foundation footing 12.

As shown in FIG. 12, in the center of the building, the sliding bearing 30 is directly arranged on the pile head of the foundation pile 11b. And between the pile heads of the foundation pile 11b, the soil concrete 15 is laid. In this example, the interstitial concrete 15 has reinforcing bars having a diameter of 13 mm in a portion from the ground level GL to a depth of 1500 mm to a depth of 1300 mm at a pitch of 200 mm in the X direction and the Y direction, and concrete (Fc = 30 N / mm ² ).

With reference to FIG. 13, the part of the pile head in which the sliding bearing is arrange | positioned is further demonstrated.
As shown in the drawing, the reinforcing bars 141 and 142 extending in the Y direction of the soil concrete 15 do not penetrate the pile head and are stopped before reaching the pile head. Reinforcing bars 143 (diameter 13 mm, length 700 mm) are radially arranged around the center of the pile head at a pitch of 20 °. These reinforcing bars 143 extend from the pile head to the soil concrete 15 and have a function of preventing cracks. Due to such a structure, the interstitial concrete 15 does not have the characteristics of an underground beam that transmits a force such as a bending moment generated in the pile head portion.

As shown in FIG. 14, in the center part of the longitudinal direction of the building 101, the sliding support 30 is directly arrange | positioned at the pile head of the foundation pile 11b. As for the pile heads of these foundation piles 11b, the soil concrete 15 is cast similarly to the short direction of the center part of the building shown in FIG. In this example, the interstitial concrete 15 has reinforcing bars having a diameter of 13 mm in a portion from the ground level GL to a depth of 1500 mm to a depth of 1300 mm at a pitch of 200 mm in the X direction and the Y direction, and concrete (Fc = 30 N / mm ² ). Moreover, the pile head of the foundation pile 11b has the same structure as the bar arrangement shown in FIG.

On the other hand, in the corner portion in the longitudinal direction, the restoration bearing 20 arranged on the foundation footing 12 provided at the pile head of the foundation pile 11a and the pile head of the foundation pile 11b inside the foundation pile 11a are arranged directly. A sliding bearing 30 is adjacent. And between the foundation footing 12 provided in the pile head of the corner foundation pile 11a and the soil concrete 15 to which the pile head of the foundation pile 11b inside is fixed, the pile of the foundation pile 11b from the foundation footing 12 An underground beam 13B is provided in which the beam back is lowered toward the head. As shown in FIG. 15, the underground beam 13B is formed by placing reinforcing bars having a diameter of 16 mm in the X direction and the Y direction at intervals of 150 mm and placing concrete (Fc = 30 N / mm ² ).

  As shown in FIG. 14, the periphery of the foundation pile 11 a on the short side of the building is a seismic isolation pit 61 that is one step lower than the soil concrete 15. And the underground beam 13B is provided so that it may continue to the soil concrete 15 as shown in FIG. That is, the underground beam 13B extends from the foundation pile 11b to the end of the foundation footing 12 on the same surface (depth 1300mm from the ground level GL) as the upper surface of the soil concrete 15 and the lower surface is the foundation pile 11b and the foundation footing. Inclined downward at an angle of 30 ° from the approximate center of 12 toward the bottom surface of the foundation footing 12.

  The soil concrete 15 provided in the center of the building shown in FIGS. 12 and 14 has a depth of 1500 mm from the ground level GL and a thickness of 200 mm. On the other hand, the underground beam 13A connecting the foundation (foundation footing 12) of the restoration bearing 20 on the short side of the building shown in FIG. 10, and the foundation (foundation footing 12) and the sliding bearing of the restoration bearing 20 shown in FIG. A part of the underground beam 13B connecting 30 foundations (pile heads of the foundation pile 11b) has a depth from the ground level GL of 1800 mm and a thickness of 200 mm, like the soil concrete 15. However, the soil concrete 15 has reinforcing bars with a diameter of 13 mm arranged at intervals of 200 mm, whereas the underground beams 13A and 13B have reinforcing bars with a diameter of 16 mm arranged at intervals of 150 mm.

  Thus, although the underground beams 13A and 13B are as thin as the interstitial concrete 15, the diameter of the reinforcing bars is increased and the amount of the reinforcing bars is increased to increase the strength.

It is a figure explaining the base isolation structure of the building which concerns on embodiment of this invention, FIG. 1 (A) is a top view which shows the arrangement | positioning state and base structure of a base isolation means, FIG.1 (B) is base structure It is sectional drawing of the 1st floor part of a building. It is a figure explaining an example of the structure of the restoration support means which is a seismic isolation support means. It is a figure explaining an example of the structure of the slide support means with a rotation mechanism which is a seismic isolation support means. It is a figure explaining the example of the building provided with the seismic isolation structure of this invention. It is a figure explaining the example of the building provided with the seismic isolation structure of this invention. It is a figure explaining the example of the building provided with the seismic isolation structure of this invention. It is a figure for demonstrating the moment which acts at the time of an earthquake, when FIG. 7 (A) uses the normal seismic isolation bearing means (laminated rubber type), FIG. 7 (B) used the sliding bearing with a rotation mechanism. In this case, FIG. 7C is a moment diagram of both. It is a figure explaining the seismic isolation structure of the building which concerns on other embodiment of this invention. In the seismic isolation structure of the building which concerns on other embodiment of this invention, it is a top view which shows the arrangement | positioning state of a seismic isolation means, and a part of foundation structure. It is a side view which shows the short side of the building of FIG. FIG. 10 is a bar arrangement diagram of a short pile head of the building of FIG. 9. It is side surface sectional drawing of the transversal direction of the building center part of FIG. FIG. 10 is a bar arrangement diagram of a pile head at the center in the longitudinal direction of the building of FIG. 9. It is a side view which shows the longitudinal direction of the building of FIG. FIG. 15 is a partially enlarged view of FIG. 14.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,101 Building 2 Pillar 3 Pedestal 5 Floor 7a, 7b Beam 7A, 7B Reverse beam 10, 110 Foundation structure 11a, 11b Foundation pile 12 Foundation footing 13A, 13B Underground beam 15 Dirt slab (concrete soil)
DESCRIPTION OF SYMBOLS 20 Restoration support 21 Upper mounting plate 22 Lower mounting plate 24 Elastic body 25 Rigid body 27 Laminated rubber body 30 Sliding bearing with rotating mechanism 31 Sliding support material 32 Sliding plate 33 Back plate 34 Anchor bolt 41 Slider 42 Recessing material 43 Convex member 44 Sliding Board 45 Filling material 61 Seismic isolation pit 70 Outer peripheral wall 80 Underfloor space 90 Concrete casting body 91 Discarded concrete 93 Split rock 131, 132, 133, 141, 142, 143 Reinforcing bar

Claims (7)

A base-isolated structure that supports a building via a plurality of base-isolated support means distributed on a foundation, wherein the plurality of base-isolated support means have a restoring force having a restoring force, and no restoring force. Includes two types of sliding support means with rotating mechanism,
In the part where the adjacent support means is a restoration support means, an underground beam is provided in the base portion between the support means,
In the part where the adjacent support means is a slide support means, there is no underground beam in the base portion between the two support means,
The surface of the portion of the foundation where the underground beam between the adjacent sliding support means is not provided is soil concrete,
A seismic isolation structure for a building , wherein at least a part of the underground beam has substantially the same thickness as the soil concrete, but the amount and structure of internal reinforcing bars are reinforced . In the part where the adjacent supporting means are the restoring supporting means and the sliding supporting means, the base part between the two supporting means is directed from the foundation under the restoring supporting means to the base part under the sliding supporting means. 2. A base-isolated structure for a building according to claim 1, wherein an underground beam with a lower beam back (beam height) is provided . The building is substantially rectangular in plan view;
At the four corners of the building and the central part of the side in the short direction, the restoration support means are arranged,
The seismic isolation structure for a building according to claim 1 or 2 , wherein the sliding support means is arranged at the center of the longitudinal side of the building. In the central portion of the long side of the building, the bottom of the bed, according to claim 3, characterized in that the beam has a relatively high rigidity to undergo bending moment occurring in the building is provided by the horizontal force of an earthquake seismic isolation structure of the serial mounting of the building. The seismic isolation structure for a building according to any one of claims 1 to 4, wherein each of the seismic isolation support means is disposed substantially at a ground level. The lowermost floor of the building has a relatively high height, and the space between the lowermost floor and the ground level can be used,
The main beam extending in one direction with the floor structure at the lowermost level is protruding downward from the floor, and the main beam extending in the other direction is protruding upward from the floor (reverse beam). The seismic isolation structure for a building according to any one of claims 1 to 5, wherein: The building base isolation structure according to any one of claims 1 to 6, wherein a height of a floor at a lowermost level of the building is about 1400 mm or less from a ground level.

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