JP7653291B2 - Building structure - Google Patents

Description

The present invention relates to building structures.

Patent Document 1 discloses technology related to vibration-damping structures that have the function of absorbing vibration energy caused by external forces such as earthquakes internally, particularly vibration-damping structures suitable for use in high-rise structures. In this prior art, at least a portion of the walls in the portions that correspond to the antinodes of the multiple natural vibration modes of the structure are configured to be freely movable in the horizontal direction, the natural periods of these walls themselves are made to approximately match the natural periods of the respective vibration modes of the structural parts, and the walls are provided with a damping function that damps their own horizontal vibrations.

Patent Document 2 discloses a technology related to a structure for improving the earthquake resistance performance of a building. In this prior art, a seismic isolation layer equipped with seismic isolation devices such as laminated rubber is provided on any floor of a building, and the entire floor above the seismic isolation layer is supported by the seismic isolation devices, and a vibration control device such as a damper is installed at any position on the upper floor supported by the seismic isolation devices. The entire upper floor supported by the seismic isolation devices is divided into a lower floor section directly supported by the seismic isolation devices and a higher floor section connected above in a tower-like shape, and vibration control devices are installed only in the higher floor section.

Patent Document 3 discloses technology related to seismic isolation structures such as seismic isolated buildings. This prior art includes one seismic isolation structure and another seismic isolation structure that are each supported by a seismic isolation device and constructed independently, and the one seismic isolation structure and the other seismic isolation structure are connected by a vibration control device that includes a spring element and a damping element. In addition, the seismic isolation device that supports either the one seismic isolation structure or the other seismic isolation structure is a sliding support.

Patent Document 4 discloses technology related to seismic isolation structures. This prior art includes a core section and a main building section adjacent to the core section, and is configured with a multi-layer seismic isolation structure consisting of a base isolation layer provided at least in the lower part of the core section and the main building section, and an intermediate seismic isolation layer provided in the middle of the main building section, and a connected vibration control structure in which the core section and the main building section are connected by a vibration control device.

Japanese Patent Application Publication No. 01-165885 Japanese Patent Application Publication No. 11-117568 JP 2017-125324 A JP 2018-009442 A

In buildings with seismic isolation structures, if the input level of seismic motion exceeds expectations during a major earthquake, the deformation of the seismic isolation layer will increase, meaning the horizontal relative displacement of the building will increase, and there is a risk that the horizontal clearance will be exceeded and the building will collide with the retaining wall. Such collisions can be prevented by increasing the damping force of damping devices such as oil dampers installed in the seismic isolation layer and suppressing the deformation of the seismic isolation layer. However, suppressing the deformation of the seismic isolation layer increases the acceleration response of the building and reduces the seismic isolation effect.

In this way, there is a trade-off between suppressing deformation of the seismic isolation layer during an earthquake and reducing the building's response acceleration.

In view of the above, the present invention aims to reduce the response acceleration of a building while suppressing deformation of the seismic isolation layer during an earthquake.

The first aspect is a building structure having a first building part of a seismic isolation structure in which a first damping device is provided in the seismic isolation layer, and a second building part of a seismic isolation structure constructed at a distance from the first building part and joined to a node of a higher mode of the natural vibration mode of the first building part, in which a second damping device is provided in the seismic isolation layer, and the second building part has a rigidity such that deformation of the seismic isolation layer of the second building part in the higher mode is zero or nearly zero.

In the first aspect of the building structure, the second building section of the seismic isolation structure is joined to the joint of the higher mode of the first building of the seismic isolation structure. The second building section has a rigidity such that the deformation of the seismic isolation layer of the second building section in the higher mode is zero or approximately zero. Therefore, in the movement due to the higher mode, the second building section hardly deforms, so the deformation or velocity input to the second damping device is zero or approximately zero, and the damping force is also zero or approximately zero. As a result, the second damping device highly damps the first building section in the primary mode to suppress the deformation of the seismic isolation layer, and prevents overdamping in the higher mode to reduce the response acceleration. Therefore, it is possible to reduce the acceleration response of the first building section while suppressing the deformation of the seismic isolation layer of the first building section during an earthquake.

The second aspect is the building structure described in the first aspect, in which the second damping device has higher damping performance than the first damping device.

In the building structure of the second embodiment, the second damping device has higher damping performance than the first damping device, and therefore the second damping device provides higher damping and suppresses deformation of the seismic isolation layer for the primary mode of the first building section, compared to a case in which the second damping device has lower damping performance than the first damping device. In addition, the second damping device suppresses deformation of the seismic isolation layer and prevents overdamping for higher modes, thereby suppressing the response acceleration of the first building.

The third aspect is a building structure having a first building section of a seismic isolation structure in which a first damping device is provided in the seismic isolation layer, and a second building section constructed at a distance from the first building section and joined via a second damping device to a node of a higher mode of the natural vibration mode of the first building section, and the second building section has a rigidity at the joint with the first building section such that the relative displacement between the first building section and the second building section in the higher mode is zero or approximately zero.

In the third aspect of the building structure, the second building section is joined to the higher mode joint of the first building section of the seismic isolation structure via the second damping device. The second building section has a rigidity at the joint with the first building section such that the relative displacement between the first building section and the second building section in the higher mode is zero or approximately zero. Therefore, in the movement due to the higher mode, the second building section is hardly deformed, so the deformation or velocity input to the second damping device is zero or approximately zero, and the damping force is also zero or approximately zero. As a result, the second damping device provides high damping for the first mode of the first building section to suppress deformation of the seismic isolation layer, and prevents overdamping for the higher mode to reduce the response acceleration. Therefore, it is possible to reduce the acceleration response of the first building section while suppressing deformation of the seismic isolation layer of the first building section during an earthquake.

The fourth aspect is the building structure described in the third aspect, in which the second damping device has higher damping performance than the first damping device.

In the building structure of the fourth aspect, the second damping device has higher damping performance than the first damping device, so the second damping device provides higher damping for the primary mode of the first building section and suppresses deformation of the seismic isolation layer. It also suppresses deformation of the seismic isolation layer and prevents overdamping for higher modes, suppressing the response acceleration of the first building.

The present invention makes it possible to reduce the response acceleration of a building while suppressing deformation of the seismic isolation layer during an earthquake.

1A is a cross-sectional view taken along line 1A-1A in FIG. 1B, which is a schematic diagram showing a seismic isolation structure to which the building structure of the first embodiment is applied, and FIG. 1B is a cross-sectional view taken along line 1B-1B in FIG. 2 is a graph showing a primary mode displacement of a natural vibration mode of a main frame part in the seismic isolation structure of FIG. 1 . 2 is a graph showing a secondary mode displacement of the natural vibration mode of the main frame of the seismic isolation structure of FIG. 1 . 2A is a diagram of an analytical model of a comparative example, and FIG. 2B is a diagram of an analytical model of the seismic isolation structure of FIG. 1 . 5 is a graph of an acceleration transfer function and a graph of a displacement transfer function analyzed using the analytical model of FIG. 4(A) and the analytical model of FIG. 4(B). 2 is a cross-sectional view corresponding to FIG. 1 , which shows a schematic illustration of a seismic isolation structure to which a building structure according to a first modified example of the first embodiment is applied. 1 , and FIG. 2 is a cross-sectional view corresponding to FIG. 1 , which shows a seismic isolation structure to which a building structure according to a second modified example of the first embodiment is applied. (A) is a graph showing the third mode displacement corresponding to Figure 3 in a seismically isolated structure to which a building structure of the third modified example of the first embodiment of (B) is applied, and (B) is a cross-sectional view corresponding to Figure 1 which shows a schematic diagram of the seismically isolated structure of the third modified example. 1A is a graph showing a second mode displacement corresponding to FIG. 3 in a structure to which the building structure of the second embodiment of FIG. 1B is applied, and FIG. 1B is a cross-sectional view corresponding to FIG. 1 that shows a schematic view of the structure of the second embodiment. 1A is a graph showing a secondary mode displacement corresponding to FIG. 3 in a structure to which a building structure according to a modified example of the second embodiment of FIG. 2B is applied, and FIG. 1B is a cross-sectional view corresponding to FIG. 1 that shows a schematic diagram of the structure according to the modified example. 1A is a cross-sectional view corresponding to FIG. 1A taken along line 11A-11A in FIG. 1B, which shows a schematic illustration of a seismic isolation structure to which a fourth variant of the first embodiment has been applied, and FIG. 1B is a cross-sectional view corresponding to FIG. 1B taken along line 11B-11B in FIG. 1A is a cross-sectional view corresponding to FIG. 1A taken along line 12A-12A in FIG. 1B, which shows a schematic illustration of a seismic isolation structure to which the fifth variant of the first embodiment has been applied, and FIG. 1B is a cross-sectional view corresponding to FIG. 1B taken along line 12B-12B in FIG.

First Embodiment
A seismic isolation structure to which the building structure of the first embodiment is applied will be described. In each drawing, hatching showing a cross section is omitted to avoid the drawing becoming complicated.

[structure]
First, the structure of the seismic isolation structure will be described.

The seismic isolation structure 10 to which the building structure 100 of this embodiment shown in FIG. 1(B) is applied is configured with a building body 30 as an example of an upper structure and a seismic isolation pit section 20 as an example of a lower structure, and is a structure with a base isolation structure with a seismic isolation layer 50 between the building body 30 and the base plate 22 of the seismic isolation pit section 20. The seismic isolation pit section 20 is configured with a base plate 22 and a retaining wall 24 provided on the outer periphery of the base plate 22.

The building structure 100 is composed of a seismic isolation layer 50, a first seismic isolation bearing 150, a first damping device 152, a second seismic isolation bearing 160, a second damping device 162, a main frame section 120 as an example of a first building section, and a core section 110.

The building body 30 is composed of a main frame section 120 as an example of a first building section, and a core section 110 as an example of a second building section. It has greater horizontal rigidity than the main frame section 120, but is not limited to this. In this embodiment, the core section 110 is provided with shared facilities such as stairs, elevator shafts, and pipe spaces, but is not limited to this.

The main frame section 120 has a void section 122 in the center of the lower part of the building (see also Figure 1 (A)). The core section 110 is constructed in the void section 122 with a distance L between it and the main frame section 120, and the upper end section 112 is rigidly connected to the upper end 124 of the void section 122.

Note that "the core section 110 is constructed with a gap between it and the main frame section 120 within the void section 122" means that "the core section 110 and the main frame section 120 are insulated from each other in structural calculations except at the upper end 124 of the void section 122," and the two may be connected by an expansion joint or the like at a point other than the upper end 124.

The upper end 124 of the void section 122 is a node FA that coincides or approximately coincides with the position of node F2 (see Figures 2 and 3) of the secondary mode of the natural vibration mode in the main frame section 120. Therefore, the core section 110 is rigidly connected to the node FA that coincides or approximately coincides with the position of node F2 of the secondary mode in the main frame section 120.

In the seismic isolation layer 50, a first seismic isolation bearing 150, a second seismic isolation bearing 160, a first damping device 152, and a second damping device 162 are installed. The first seismic isolation bearing 150 and the first damping device 152 are installed directly below the main frame section 120, and the second seismic isolation bearing 160 and the second damping device 162 are installed directly below the core section 110.

The portion of the seismic isolation layer 50 where the first seismic isolation bearing 150 and the first damping device 152 are installed directly below the main frame section 120 is referred to as the first seismic isolation layer 52, and the portion where the second seismic isolation bearing 160 and the second damping device 162 are installed directly below the core section 110 is referred to as the second seismic isolation layer 54.

The core section 110 has a rigidity such that the deformation of the second seismic isolation layer 54 of the core section 110 in the secondary mode is zero or nearly zero. In addition, the second damping device 162 has a higher damping performance than the first damping device 152.

In addition, "damping performance" refers to the damping coefficient in the case of velocity-dependent damping devices such as oil dampers and viscous dampers, and refers to the area traced by the hysteresis up to a certain deformation in the case of displacement-dependent damping devices such as hysteresis dampers. This also applies to the following descriptions.

The main frame section 120 is supported by a first seismic isolation bearing 150, and the core section 110 is supported by a second seismic isolation bearing 160. The rigidity of the second seismic isolation bearing 160 is set to be smaller than the rigidity of the first seismic isolation bearing 150, but is not limited to this.

When the first seismic isolation bearing 150 and the second seismic isolation bearing 160 are each composed of multiple seismic isolation bearings, the total stiffness of the multiple seismic isolation bearings that compose the second seismic isolation bearing 160 is set to be smaller than the total stiffness of the multiple seismic isolation bearings that compose the second seismic isolation bearing 160. From another perspective, the stiffness of the second seismic isolation layer 54 is set to be smaller than the stiffness of the first seismic isolation layer 52.

In this embodiment, the first seismic isolation bearing 150 is composed of multiple laminated rubber bearings, and the second seismic isolation bearing 160 is composed of multiple sliding bearings, but this is not limited to this.

The first damping device 152 is connected to the base plate 22 and the bottom 128 of the main frame section 120, and the second damping device 162 is connected to the base plate 22 and the bottom 118 of the core section 110. The second damping device 162 has higher damping performance than the first damping device 152, but is not limited to this.

In addition, when the first damping device 152 and the second damping device 162 are composed of damping devices such as multiple dampers, the total damping performance of the multiple damping devices that compose the second damping device 162 is set to be higher than the total damping performance of the second damping device 162.

In this embodiment, the damping performance of the second damping device 162 is set to be higher than the damping performance of the first damping device 152 by adjusting the number of damping devices, such as oil dampers, that constitute the first damping device 152 and the second damping device 162, but this is not limited to the above.

Now, we will explain the graphs in Figures 2 and 3.

Figure 2 shows the horizontal displacement of the main frame section 120 and the core section 110 in the primary mode of the natural vibration mode of the main frame section 120. Figure 3 shows the horizontal displacement of the main frame section 120 and the core section 110 in the secondary mode of the natural vibration mode of the main frame section 120.

Figure 2 shows that the core section 110 is rigidly connected to node FA (see upper end 124 in Figure 1 ) which coincides or nearly coincides with node F2 of the secondary mode of the natural vibration mode of the main frame section 120.

Figure 3 shows that the horizontal displacement of the core section 110 in the secondary mode of the natural vibration mode of the main frame section 120 is zero.

The specifications of the analytical model in Figure 4(B), which was used to calculate the graphs in Figures 2 and 3, are as follows:

In the analysis model shown in Figure 4 (B), the main frame section 120 is a 30-mass model, with the mass of each story being 2000t, the floor height of each story being 4m, the natural period when the foundation is fixed being 2.4s, and the rigidity distribution being a trapezoidal distribution in which the rigidity of the top story is 0.3 times that of the first story. In addition, the core section 110 is assumed to have 0.5 times the mass and 5.0 times the rigidity of the main frame section 120, and is connected at the 18th story of the main frame section 120.

The first seismic isolation bearing 150 (first seismic isolation layer 52) was given a rigidity such that the natural period would be 6.0 s when the main frame section 120 and the core section 110 were assumed to be one mass point, and an extremely small rigidity was given to the second seismic isolation bearing 160 (second seismic isolation layer 54).

The results of the analysis using the analytical model will be discussed later.

[Action and Effect]
Next, the operation and effects of this embodiment will be described.

The core portion 110 of the seismic isolation structure 10 to which the building structure 100 of this embodiment is applied is joined to a node portion FA that coincides or nearly coincides with a node F2 of the secondary mode of the natural vibration mode in the main frame portion 120. The core portion 110 also has a rigidity such that the deformation of the second seismic isolation layer 54 of the core portion 110 in the secondary mode is zero or nearly zero. Therefore, in the movement due to the secondary mode during an earthquake, the core portion 110 hardly deforms, so the deformation or velocity input to the second damping device 162 is zero or nearly zero, and the damping force is also zero or nearly zero.

As a result, as shown in FIG. 2, the second damping device 162 provides high damping for the first mode to suppress deformation of the seismic isolation layer 50, i.e., suppresses the horizontal relative displacement of the main frame section 120, and prevents collision with the retaining wall 24. On the other hand, as shown in FIG. 3, the second damping device 162 prevents overdamping for the second mode, increases the displacement of the main frame section 120, and reduces the response acceleration. Therefore, it is possible to reduce the acceleration response of the main frame section 120 while suppressing excessive deformation of the seismic isolation layer 50 during earthquakes, particularly large earthquakes.

In addition, since the second damping device 162 has higher damping performance than the first damping device 152, the second damping device 162 provides higher damping for the primary mode of the main frame section 120, thereby suppressing deformation of the seismic isolation layer 50.

(Analysis results of the analysis model)
Next, the analysis results of the analysis model will be described.

Figure 4 (A) is an analytical model of a comparative example of a base isolation structure. The upper structure of the comparative example is a 30-mass model, similar to the analytical model of the base isolation structure 10 of this embodiment to which the building structure 100 is applied (see Figure 4 (B)), with the mass of each story being 2000t, the floor height being 4m, and the natural period when the foundation is fixed being 2.4s. The stiffness distribution of the upper structure is a trapezoidal distribution in which the stiffness of the top layer is 0.3 times that of the bottom layer, and the damping constant of the main frame section 120 is 1.5%. The natural period of the base isolation layer is 6.0s when the upper structure is assumed to be a single mass, and the damping constant h at this time is used as a parameter.

Figure 4 (B) shows an analytical model of the seismic isolation structure 10 of this embodiment to which the building structure 100 is applied as described above.

A damping constant h that is 10% of the damping constant was added to the first seismic isolation bearing 150 (first seismic isolation layer 52) of the main frame section 120, and the remaining amount was added to the second seismic isolation bearing 160 (second seismic isolation layer 54) of the core section 110. The stiffness of the second seismic isolation bearing 160 (second seismic isolation layer 54) of the core section 110 was set to an extremely small value.

Figure 5 shows the acceleration transfer function (top absolute acceleration/ground acceleration) and displacement transfer function (deformation of seismic isolation layer/ground displacement) in the comparative example analysis model and the analysis model to which building structure 100 is applied. It also shows the results of analysis when the damping constant is 20% (h = 20%), 40% (h = 40%), and 60% (h = 60%).

The damping coefficient of the main frame section 120 can be calculated for each story using the damping constant h of the main frame section 120 itself excluding the first damping device 152, using the following formula:

ci = 2hki/ω
ci: damping coefficient of the i-th floor h: damping constant of the main frame (h = 1.5% in this example)
ki: stiffness of the i-th story of the main frame ω: primary circular frequency of the main frame (2π/T (T is the natural period when the foundation is fixed))
i: Main frame floor

The damping coefficient of the first damping device 152 installed in the first seismic isolation layer 52 can be calculated using the following formula. In this study, the same value as the damping coefficient calculated for the comparative example is also given to the analysis model of the seismic isolation structure 10.

c = 2hk/ω
k: stiffness of the seismic isolation layer ω: primary circular frequency of the seismic isolation structure (period when the upper structure is assumed to be one mass point)

The aforementioned "damping coefficient that is 10% of the damping constant" is a value calculated using the above formula with h = 0.1, and this is added to the first damping device 152 of the first seismic isolation layer 52 of the main frame section 120. Also, if the overall damping constant h is 60%,

h=0.6-0.1
= 0.5

This damping constant h adds a damping coefficient of 50% to the second damping device 162 of the second seismic isolation layer 54 of the core section 110.

As can be seen from FIG. 5, the analytical model of the comparative example and the analytical model of the seismic isolation structure 10 to which the building structure 100 is applied are given the same damping coefficient, so the damping constant of the analytical model of the seismic isolation structure 10 is smaller than that of the analytical model of the comparative example.

Therefore, at h = 20%, the analysis model of the seismic isolation structure 10 has slightly larger peaks in the first mode for both the acceleration transfer function and the displacement transfer function.

However, the amount of deformation input to the second damping device 162 is greater in the analytical model of the seismic isolation structure 10 than in the analytical model of the comparative example, so the effect is amplified, and at h = 40% and h = 60%, the primary peaks of both the acceleration transfer function and the displacement transfer function are smaller than those in the analytical model.

In addition, in the analytical model of the comparative example, the secondary peak of the acceleration transfer function tends to increase with an increase in the damping constant h. In contrast, in the analytical model of the seismic isolation structure 10, the degree of increase in the secondary peak of the acceleration transfer function due to an increase in the damping constant h is suppressed, and the amplitude in the frequency band around the secondary peak is smaller than in the comparative example.

In addition, the displacement transfer function of the analysis model to which the seismic isolation structure 10 of this embodiment is applied increases in the high frequency range, but a separate earthquake response analysis has confirmed that the deformation of the first seismic isolation layer 52 of the main frame section 120 does not increase, and that the displacement response reduction effect is greater than that of the comparative example analysis model.

[Modification]
Next, modified examples of this embodiment will be described. Note that in the drawings of each modified example, hatching indicating a cross section is omitted to avoid the drawings becoming complicated.

(First Modification)
The seismic isolation structure 11 to which the first modified building structure 101 shown in Figure 6 is applied is composed of a building main body 31 as an example of an upper structure and a seismic isolation pit section 20 as an example of a lower structure, and is a structure with a base isolation structure having a seismic isolation layer 50 composed of a first seismic isolation layer 52 and a second seismic isolation layer 54 between the building main body 31 and the base 22 of the seismic isolation pit section 20.

The building body 31 is composed of a main frame section 121 as an example of a first building section, and a core section 111 as an example of a second building section. The core section 111 has greater horizontal rigidity than the main frame section 121, but is not limited to this. The main frame section 121 has a void section 122 in the center of the lower part of the building. The core section 111 is constructed within the void section 122 with a distance L between it and the main frame section 121, and the middle section 113 is rigidly connected to the upper end 124 of the void section 122.

Furthermore, the core section 111 is constructed up to the top floor of the main frame section 121, and is rigidly connected to the main frame section 121 from the top end 124 to the top floor. In other words, the core section 111 is rigidly connected to the main frame section 121 from the middle section 113 to the top end section 114.

The core section 111 may be connected to the main frame section 121 by an expansion joint or the like, other than between the middle section 113 and the upper end section 114.

In this modified example, the seismic isolation structure 11 has the core portion 111 joined to a node portion FA that coincides or nearly coincides with a node F2 of the secondary mode of the natural vibration mode of the main frame portion 121. The core portion 111 also has a rigidity such that the deformation of the second seismic isolation layer 54 of the core portion 111 in the secondary mode is zero or nearly zero.

This makes it possible to reduce the acceleration response of the main frame section 121 while suppressing excessive deformation of the seismic isolation layer 50 during an earthquake, particularly a major earthquake.

The core section 111 is rigidly joined to the main frame section 121 from the middle section 113 to the upper end section 114. This suppresses the displacement of the core section 111, and makes it possible to narrow the distance L between the main frame section 121 and the core section 111 within the void section 122.

(Second Modification)
The seismic isolation structure 12 to which the second modified building structure 102 shown in Figure 7 is applied is composed of a building main body 32 as an example of an upper structure and a seismic isolation pit portion 20 as an example of a lower structure, and is a structure with a base isolation structure having a seismic isolation layer 50 composed of a first seismic isolation layer 52 and a second seismic isolation layer 54 between the building main body 32 and the base 22 of the seismic isolation pit portion 20.

The building body 32 has a truss structure 190 provided on the upper end 124 of the void 122 in the main frame section 123. The upper end 112 of the core section 110 is rigidly joined to the truss structure 190.

In this modified example, the core portion 110 of the seismic isolation structure 12 is joined to a node FA that coincides or nearly coincides with a node F2 of the secondary mode of the natural vibration mode of the main frame portion 123. The core portion 110 also has a rigidity such that the deformation of the second seismic isolation layer 54 of the core portion 110 in the secondary mode is zero or nearly zero.

This makes it possible to reduce the acceleration response of the main frame section 123 while suppressing excessive deformation of the seismic isolation layer 50 during an earthquake, particularly a major earthquake.

The upper end of the core section 110 is rigidly connected to a truss structure 190 provided on the main frame section 123. This suppresses the displacement of the core section 110, and makes it possible to narrow the distance L between the main frame section 123 and the core section 110 within the void section 122.

(Third Modification)
The seismic isolation structure 13 to which the third modified building structure 103 shown in Figure 8 (B) is applied is composed of a building main body 33 as an example of an upper structure and a seismic isolation pit section 20 as an example of a lower structure, and is a structure with a base isolation structure having a seismic isolation layer 50 composed of a first seismic isolation layer 52 and a second seismic isolation layer 54 between the building main body 33 and the base 22 of the seismic isolation pit section 20.

The building body 33 is composed of a main frame section 220 as an example of a first building section, and a core section 210 as an example of a second building section. The core section 210 has greater horizontal rigidity than the main frame section 220, but is not limited to this. The main frame section 220 has a void section 222 in the center of the lower part of the building. The core section 210 is constructed with a distance L between it and the main frame section 220 within the void section 222, and the upper end section 212 is rigidly joined to the upper end 224 of the void section 222.

The core section 210 may be connected to the main frame section 220 at a point other than the upper end section 212 by an expansion joint or the like.

The upper end 224 of the void section 222 is a node FB that coincides or nearly coincides with the position of node F3 (see FIG. 8A) in the tertiary mode of the natural vibration mode of the main frame section 220. Therefore, the core section 210 is rigidly connected to the main frame section 220 at node FB that coincides or nearly coincides with node F3 in the tertiary mode.

In this modified example, the core portion 210 of the seismic isolation structure 13 is joined to a node portion FB that coincides or nearly coincides with a node F3 of the tertiary mode of the natural vibration mode of the main frame portion 220. In addition, the core portion 210 has a rigidity such that the deformation of the second seismic isolation layer 54 of the core portion 210 in the tertiary mode is zero or nearly zero.

This makes it possible to reduce the acceleration response of the main frame section 220 while suppressing excessive deformation of the seismic isolation layer 50 during an earthquake, particularly a major earthquake.

In addition, since the core section 210 is rigidly joined to the node FB that coincides or nearly coincides with the node F3 of the third mode of the main frame section 220, the stiffness of the core section 210 is reduced. Therefore, it is easy to increase the horizontal rigidity of the core section 210.

(Fourth Modification)
The seismic isolation structure 14 to which the fourth modified building structure 104 shown in Figure 11 (B) is applied is composed of a building main body 34 as an example of an upper structure and a seismic isolation pit section 20 as an example of a lower structure, and is a structure with a base isolation structure having a seismic isolation layer 50 composed of a first seismic isolation layer 52 and a second seismic isolation layer 54 between the building main body 34 and the base 22 of the seismic isolation pit section 20.

The building body 34 is composed of a main frame section 240 as an example of a first building section, and a core section 230 as an example of a second building section. The core section 230 has greater horizontal rigidity than the main frame section 220, but is not limited to this. The main frame section 240 has a recess 242 in the lower part of the building (see also FIG. 11(A)). The core section 230 is constructed within the recess 242 with a distance L between it and the main frame section 220, and the upper end section 232 is rigidly joined to the upper end 244 of the recess 242.

The core section 230 may be connected to the main frame section 240 at a point other than the upper end section 232 by an expansion joint or the like.

The upper end 244 of the recess 242 is a node FA that coincides or approximately coincides with the position of node F2 in the secondary mode of the natural vibration mode of the main frame 240. Therefore, the core 230 is rigidly joined to the main frame 240 at node FA that coincides or approximately coincides with node F2 in the secondary mode.

In this modified example, the core portion 230 of the seismic isolation structure 14 is joined to a node FA that coincides or nearly coincides with a node F2 of the secondary mode of the natural vibration mode of the main frame portion 240. The core portion 230 is also designed to have a rigidity such that the deformation of the second seismic isolation layer 54 of the core portion 230 in the secondary mode is zero or nearly zero.

This makes it possible to reduce the acceleration response of the main frame section 240 while suppressing excessive deformation of the seismic isolation layer 50 during an earthquake, particularly a major earthquake.

(Fifth Modification)
The seismic isolation structure 15 to which the building structure 105 of the fifth modified example shown in Figure 12 (B) is applied is composed of a building main body 35 as an example of an upper structure and a seismic isolation pit section 20 as an example of a lower structure, and is a structure with a base isolation structure having a seismic isolation layer 50 composed of a first seismic isolation layer 52 and a second seismic isolation layer 54 between the building main body 35 and the base 22 of the seismic isolation pit section 20.

The building body 35 is composed of a high-rise section 260 as an example of a first building section, and a low-rise section 250 as an example of a second building section. The low-rise section 250 has greater horizontal rigidity than the high-rise section 260, but is not limited to this. The low-rise section 250 is set back relative to the high-rise section 260 and constructed with a distance L between it and the high-rise section 260 (see also FIG. 12(A)), and a protruding section 254 protruding from an upper end section 252 is rigidly joined to a joint section 262 of the high-rise section 260.

The low-rise section 250 may be connected to the high-rise section 260 by an expansion joint or the like at a point other than the protruding section 254.

The joint 262 of the high rise section 260 is a node FA that coincides or nearly coincides with the position of node F2 in the secondary mode of the natural vibration mode of the high rise section 260. Therefore, the low rise section 250 is rigidly joined to the high rise section 260 at a node FA that coincides or nearly coincides with node F2 in the secondary mode.

In this modified example, the low-rise section 250 of the seismic isolation structure 15 is joined to a node FA that coincides or nearly coincides with a node F2 of the secondary mode of the natural vibration mode of the high-rise section 260. In addition, the low-rise section 250 has a rigidity such that the deformation of the second seismic isolation layer 54 of the low-rise section 250 in the secondary mode is zero or nearly zero.

This makes it possible to reduce the acceleration response of the upper section 260 while suppressing excessive deformation of the seismic isolation layer 50 during an earthquake, particularly a major earthquake.

In addition, the building body 35 in this modified example is configured to have a main frame section and a core section that has greater horizontal rigidity than the main frame section, and the core section may be constructed with a setback relative to the main frame section.

Second Embodiment
Next, a seismic isolation structure to which the building structure of the second embodiment is applied will be described. The same members as those in the first embodiment are given the same reference numerals, and duplicated descriptions will be omitted or simplified. In addition, in each drawing of the second embodiment and its modified examples, hatching showing cross sections is omitted to avoid cluttering the drawings.

[structure]
First, the structure of the seismic isolation structure will be described.

As shown in FIG. 9(B), the structure 16 to which the building structure 300 of this embodiment is applied has a first building section 320, a second building section 310, and a seismic isolation pit section 20. The first building section 320 is a base isolation structure that has a seismic isolation layer 55 between it and the base 22 of the seismic isolation pit section 20. The first building section 320 also has a void section 322 in the center of the lower part of the building.

The second building section 310 is constructed in the open void section 322 with a distance L between it and the first building section 320. The second building section 310 is a non-earthquake-isolated building constructed on a base 22. The upper end 312 of the second building section 310 is connected to the upper end 324 of the open void section 322 via the second damping device 162.

The upper end 324 of the void section 322 is a node FA that coincides or nearly coincides with the position of node F2 (see FIG. 9A) in the secondary mode of the natural vibration mode of the first building section 320. Therefore, the first building section 320 is connected to the second building section 310 via the second damping device 162 at node FA that coincides or nearly coincides with node F2 in the secondary mode.

In this embodiment, a second seismic isolation bearing 160 is provided between the upper end 312 of the second building section 310 and the upper end 324 of the open void section 322. However, the second seismic isolation bearing 160 does not necessarily have to be provided.

The second building section 310 may also be connected to the first building section 320 by an expansion joint or the like.

The second damping device 162 provided at the connection between the joint FA of the first building section 320 of the structure 16 and the second building section 310 has higher damping performance than the first damping device 152, but is not limited to this.

The second building section 310 has a rigidity at the joint with the first building section 320 such that the relative displacement between the first building section 320 and the second building section 310 in the secondary mode is zero or approximately zero. In addition, the second damping device 162 has a higher damping performance than the first damping device 152.

[Action and Effect]
Next, the operation and effects of this embodiment will be described.

The second building section 310 is joined via the second damping device 162 to a node FA that coincides or nearly coincides with a node F2 of the secondary mode of the natural vibration mode of the first building section 320 of the structure 16 to which the building structure 300 is applied. In addition, the second building section 310 has a rigidity at the joint with the first building section 320 such that the relative displacement between the first building section 320 and the second building section 310 in the secondary mode is zero or nearly zero. Therefore, in the movement due to the secondary mode during an earthquake, there is almost no relative displacement between the first building section 320 and the second building section 310, so the deformation or velocity input to the second damping device 162 is zero or nearly zero, and the damping force is also zero or nearly zero.

As a result, the second damping device 162 provides high damping for the primary mode to suppress deformation of the seismic isolation layer 55, and prevents overdamping for the secondary mode, increasing the displacement of the first building section 320 and reducing the response acceleration. Therefore, it is possible to reduce the acceleration response of the first building section 320 while suppressing excessive deformation of the seismic isolation layer 55 during an earthquake, particularly a major earthquake.

In addition, since the second damping device 162 has higher damping performance than the first damping device 152, the second damping device 162 provides higher damping for the primary mode of the main frame section 120, thereby suppressing deformation of the seismic isolation layer 55.

[Modification]
Next, a modification of this embodiment will be described.

The structure 17 to which the modified building structure 302 shown in FIG. 10(B) is applied includes a seismic isolation pit section 20, a first building section 321, and a second building section 311. The first building section 321 is a building with a base isolation structure that includes a seismic isolation layer 56 between the base plate 22 of the seismic isolation pit section 20 and the first building section 321.

The second building section 311 is constructed adjacent to the first building section 321 with a distance L therebetween. The second building section 311 is a non-seismic building constructed on a base plate 22. The upper end section 313 of the second building section 311 is connected to the first building section 321 via a second damping device 162.

The portion of the first building section 321 that is connected to the second building section 311 via the second damping device 162 is a node FA that coincides or approximately coincides with the position of node F2 (see FIG. 10(A)) in the secondary mode of the natural vibration mode of the first building section 321.

The second building section 311 may be connected to the first building section 321 by an expansion joint or the like.

The second building section 311 has a rigidity at the joint with the first building section 321 such that the relative displacement between the first building section 321 and the second building section 311 in the secondary mode is zero or approximately zero.

The second damping device 162 therefore provides high damping for the primary mode to suppress deformation of the seismic isolation layer 56, and prevents overdamping for the secondary mode, increasing the displacement of the first building section 321 and reducing the response acceleration. This makes it possible to reduce the acceleration response of the first building section 321 while suppressing excessive deformation of the seismic isolation layer 56 during earthquakes, particularly large earthquakes.

＜Other＞
The present invention is not limited to the above embodiment.

For example, in the above embodiment and modified example, the second building section (core section 110, 111, 210, 230, low-rise section 250, second building section 310, 311) is connected to nodes FA and FB that coincide or nearly coincide with node F2 of the second-order mode or node F3 of the third-order mode of the natural vibration mode of the first building section (main frame section 120, 121, 123, 220, 240, high-rise section 260, first building section 320, 321) via a rigid joint or a second damping device 162, but this is not limited to this. A similar structure may be used for the fourth or higher order modes of the natural vibration mode of the first building section.

For example, in the first embodiment and its modified examples described above, the second building section (core sections 110, 111, 210, 230, low-rise section 250) was supported by the second seismic isolation bearing 160, but this is not limited thereto, and the structure may not include the second seismic isolation bearing 160.

For example, in the first embodiment and its modified examples described above, the first building section (main frame sections 120, 121, 123, 210, 220) and the second building section (core sections 110, 111, 210) were both of the foundation seismic isolation structure, but this is not limited to this, and the first building section and the second building section may be of an intermediate seismic isolation structure, or one of the two may be of a foundation seismic isolation structure and the other of the two may be of an intermediate seismic isolation structure.

In addition, for example, in the second embodiment and its modified example described above, the first building sections 320, 321 have a foundation seismic isolation structure, but this is not limited to this and may also be an intermediate seismic isolation structure.

Furthermore, the present invention may be implemented in various forms without departing from the spirit of the invention. Multiple embodiments and modifications may be implemented in combination as appropriate.

50 Seismic isolation layer 55 Seismic isolation layer 56 Seismic isolation layer 100 Building structure 101 Building structure 102 Building structure 103 Building structure 104 Building structure 105 Building structure 110 Core portion (an example of a second building portion)
111 Core section (an example of the second building section)
120 Main frame section (an example of the first building section)
121 Main frame section (an example of the first building section)
123 Main frame (example of the first building section)
150 First seismic isolation bearing 152 First damping device 160 Second seismic isolation bearing 162 Second damping device 210 Core portion (an example of a second building portion)
220 Main frame section (an example of the first building section)
230 Core section (an example of the second building section)
240 Main frame (an example of the first building section)
250 Low-rise section (example of the second building section)
260 High-rise section (example of the first building section)
300 Building structure 302 Building structure 310 Second building section 311 Second building section 320 First building section 321 First building section

Claims (4)

a first building portion of a seismic isolation structure constructed on a first seismic isolation layer configured by installing a first seismic isolation bearing and a first damping device on a substructure;
A second building part of a seismic isolation structure constructed at a distance from the first building part on a second seismic isolation layer constituted by installing a second seismic isolation bearing and a second damping device on the lower structure;
Equipped with
The rigidity of the second seismic isolation bearing is set to approximately 0,
The second building section is rigidly connected to a node section which is a node of a higher mode of a natural vibration mode of the first building section,
The horizontal rigidity of the second building section is set so that the horizontal deformation amount of the second seismic isolation layer in the higher mode is 0 or approximately 0.
Building structure. The second seismic isolation bearing is a sliding bearing,
The second damping device has a higher damping performance than the first damping device.
2. The building structure of claim 1. a first building portion having a seismic isolation structure constructed on a seismic isolation layer constituted by a first seismic isolation bearing and a first damping device installed in a substructure;
A second building section of a non-seismic isolation structure rigidly connected to the lower structure and constructed at a distance from the first building section ;
Equipped with
The second building section has an upper end connected to a node section that is a node of a higher mode of a natural vibration mode of the first building section by a second damping device ,
The horizontal rigidity of the second building section is set so that the horizontal displacement of the second building section in the higher mode is 0 or approximately 0 from the lower end to the upper end of the second building section.
Building structure. The second damping device has a higher damping performance than the first damping device.
4. The building structure of claim 3.