JP3677701B2 - Damping structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vibration control structure that includes a mechanism for suppressing a vibration response due to an earthquake or the like, and is particularly preferably constructed on a soft ground.
[0002]
[Prior art]
As is well known, various basic methods for constructing a structure on soft ground have been realized in recent years. As an example, the structure 1 is mounted on the ground 2 as shown in FIG. The construction method to build is mentioned.
[0003]
In FIG. 10A, the structure 1 includes a lower structure 3 constructed in the ground 2 and an upper structure 4 supported by the lower structure 3.
The lower structure 4 includes a ground improvement body 8 formed by solidifying a part of the surface layer ground 7 located on the support ground 6 in the ground 2 by performing a deep foundation mixing process, and the support ground 6. The base pile 9 is placed in the surface ground 7 so that at least the lower end thereof reaches.
[0004]
FIG. 10B is a diagram showing a horizontal section of the lower structure 3. As shown in the figure, the ground improvement body 8 is formed near the center below the upper structure 4 in the surface ground 7. The foundation pile 9 is driven around it.
[0005]
As shown in FIG. 10, when the structure 1 is constructed, the ground improvement body 8 can suppress the deformation and secular deformation of the surface ground 7 and thereby the stress acting on the foundation pile 9. Thus, the structure 1 can be stabilized.
[0006]
[Problems to be solved by the invention]
In the structure 1 described above, the ground improvement body 8 is formed for the purpose of suppressing the deformation of the ground 2, whereby the upper structure 4 is connected via the ground improvement body 8. During the earthquake, the vibration response of the upper structure 4 is not suppressed, and it is difficult to maintain the safety of the upper structure 4.
[0007]
In view of the above circumstances, the present invention provides a vibration damping structure that maintains the stability of the structure even on soft ground, and also maintains the safety of the upper structure during an earthquake. Is the purpose.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the following means are employed in the present invention.
The vibration damping structure according to claim 1 comprises a lower structure constructed on a support ground in the ground, and an upper structure supported by the lower structure,
The lower structure has a lower end abutting against the support ground, and an upper end fixed to the upper structure to support a central portion of the upper structure, and an upper end of the lower structure It is configured to include a peripheral structure of the upper structure and an underground structure connected via a damper,
The lower end of the support structure, when seen in sectional side view with at least one vertical plane, when the support structure and the upper structure is vibrated, has two points spaced apart in a horizontal direction as a fulcrum alternately It is assumed
The support structure is composed of a ground improvement body obtained by consolidating a part of the surface ground located on the support ground, and a horizontal sectional area at a lower end portion of the ground improvement body is larger than a horizontal sectional area at an upper end portion. The lower end edge of the ground improvement body abuts on the support ground and serves as the fulcrum, thereby locking the support structure and the upper structure when the vibration is caused to operate the damper; It is characterized by being.
[0009]
In this vibration damping structure, when horizontal vibration is applied during an earthquake, the two points at the lower end of the ground improvement body as a support structure are alternately supported as supporting points. The upper structure and the support structure are locked together. Moreover, the vibration energy accompanying this rocking is absorbed by the damper interposed between the upper structure and the underground structure. Moreover, since the ground improvement body is used as the support structure, in this vibration damping structure, the deformation of the surface layer ground caused by the earthquake and the secular change is suppressed by the ground improvement body.
[0010]
The damping structure according to claim 2 is placed in the ground so that the lower end of the damping structure as the supporting structure in the damping structure according to claim 1 reaches the supporting ground. The support pile is provided, and the lower end portion of the support pile serves as the fulcrum so that the damper is operated by locking them when the support structure and the upper structure are vibrated. It is characterized by.
[0011]
In this vibration damping structure, the placement position of the support pile is the position of the fulcrum when the support structure and the upper structure are rocking deformed.
[0012]
A vibration damping structure according to claim 3 is the vibration damping structure according to claim 1 or 2, wherein the underground structure is composed of a foundation pile placed in the ground. To do.
[0013]
Since the above structure is adopted, in this vibration damping structure, even when the support structure and the upper structure are locked, the underground structure is not displaced in the vertical direction. The damper interposed between the middle structure and the upper structure can absorb the vibration energy due to the rocking well.
[0016]
The vibration damping structure according to claim 4 is the vibration damping structure according to any one of claims 1 to 3 , wherein the support structure is a plan view of a lower part of the upper structure. While being provided in the fixed area | region, the said underground structure is provided in the circumference | surroundings of the said support structure.
[0017]
In this vibration damping structure, since the support structure is provided in a certain region, it is possible to easily cause locking in the support structure and the upper structure.
[0018]
A vibration damping structure according to a fifth aspect is the vibration damping structure according to any one of the first to fourth aspects, wherein the damper is an oil damper.
In this vibration damping structure, vibration energy when the system composed of the support structure and the upper structure is locked can be efficiently absorbed.
[0019]
A vibration damping structure according to claim 6 is the vibration damping structure according to any one of claims 1 to 5 , wherein the upper structure is interposed between the upper structure and the underground structure. A jack for adjusting the vertical position of at least a part of the structure is provided.
[0020]
In this vibration damping structure, when a part of the upper structure is displaced in the vertical direction due to subsidence or the like after the earthquake, the displacement can be corrected by driving the jack.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a vibration damping structure 13 constructed on the ground 11. The damping structure 13 includes a lower structure 15 built in the ground and an upper structure 16 supported by the lower structure 15.
[0022]
The lower structure 15 includes a ground improvement body (support structure) 19 formed on the support ground 18 in the ground 11, and a foundation pile (underground structure) 20 placed around the ground improvement body 19, 20... The ground improvement body 19 is formed by mixing a stabilizing material such as lime or cement with the surface layer ground 21 located on the support ground 18 and further agitating them to solidify a part of the surface layer ground 21. The foundation piles 20, 20,... Are support piles placed in the surface layer ground 21 so that the lower ends thereof reach the support ground 18.
[0023]
As shown in the drawing, the ground improvement body 19 is configured to support the foundation beam 22 of the upper structure 16 at the upper end portion 19a and to contact the support ground 18 at the lower end portion 19b. Further, the lower end portion 19b of the ground improvement body 19 is formed so as to protrude downward from the main body portion 19c, and the cross-sectional area in the horizontal plane is smaller than the cross-sectional area in the horizontal plane in the upper end portion 19a. It is configured.
[0024]
Further, the ground improvement body 19 and the foundation piles 20, 20,... Are integrally configured to support the foundation beam 22 of the upper structure 16, and the upper structure standing on the foundation beam 22. Among the pillars 23, 23,... On the first floor of 16, a damper portion 25 is provided between the lower end 23 a and the foundation pile 20 for those located above the foundation piles 20, 20,. .
[0025]
FIG. 2 is a diagram showing a horizontal cross section of the lower structure 15. As shown in FIG. 2, the ground improvement body 19 is formed in a certain region near the center below the upper structure 16, and the foundation piles 20, 20,... Are driven around the ground improvement body 19. Yes.
[0026]
FIG. 3 is a diagram showing the state of the damper portion 25 and the vicinity thereof. As shown in the drawing, the foundation pile 20 has an upper end 20a connected to an intersection 26 of the foundation beams 22, 22, and the foundation beams 22, 22 and a floor slab 27 provided above the foundation beams. It is set as the structure supported from the downward direction. Moreover, the damper part 25 is comprised by the oil dampers 30 and 30 which connect between the floor slab 27 fixed to the upper end part 20a side of the foundation pile 20, and the lower end part 23a of the pillar 23 located above it. Yes. Further, a clearance 31 is provided between the floor slab 27 and the lower end portion 23 a of the column 23.
[0027]
Each oil damper 30 includes a cylinder 30a filled with oil inside and a piston rod 30b inserted into the cylinder 30a. The cylinder 30a is fixed to the floor slab 27 side, and the piston rod 30b. Is fixed to the lower end 23 a of the column 23. Further, these oil dampers 30 and 30 do not support the vertical load acting on the column 23, and allow the lower end portion 23a and the floor slab 27 to allow relative displacement in the vertical direction and restrict relative displacement in the horizontal direction. It is set as the structure connected to. In other words, the pillar 23, the foundation beam 22, and the foundation pile 20 are cut off at the damper portion 25, and the load of the upper structure 16 is transmitted downward only to the pillar 23 where the damper portion 25 is not provided. . Therefore, the load of the upper structure 16 is mainly supported by the ground improvement body 19.
[0028]
The above is the main configuration of the present embodiment. Next, the operation of the damping structure 13 during an earthquake will be described.
As shown in FIG. 1, the ground improvement body 19 has a lower end portion 19b whose horizontal cross-sectional area is smaller than the upper end portion 19a and the main body portion 19c, and protrudes downward from the main body portion 19c. It is set as the structure contact | abutted. In the ground improvement body 19, when the moment about the axis orthogonal to the cross section shown in FIG. Since it is proportional to the width dimension L, by narrowing the horizontal cross-sectional area of the lower end portion 19b in this way, the ground improvement body 19 can be lifted from the support ground 18 when a large-scale earthquake occurs.
[0029]
FIG. 4 is a graph showing the relationship between the moment M and the rotation angle R at the lower end 19 b of the ground improvement body 19. The moment when the ground improvement body 19 is lifted up is expressed as WL / when the sum of the masses of the ground improvement body 19 and the upper structure 16 that is considered to be displaced together with the ground improvement body 19 is W. Therefore, when the moment M exceeds WL / 6, the ground improvement body 19 is lifted from the support ground 18. When the ground improvement body 19 is lifted from the support ground 18, the reaction force that the ground improvement body 19 receives from the support ground 18 is greatly reduced. As shown in FIG. Will increase the rotation angle R.
[0030]
In this way, when the rotation of the lower end portion 19 b of the ground improvement body 19 increases, the upper structure 16 supported from the ground improvement body 19 also vibrates together with the ground improvement body 19. However, since the movable direction of the upper structure 16 is limited by the oil damper 30 attached to the lower end portion 23a of the column 23 as described above, as a result, the upper structure 16 and the ground improvement body 19 As a result, as shown in FIG. 5, rocking vibration occurs such that the lower end edges 19 d and 19 d of the ground improvement body 19 are alternately used as fulcrums.
[0031]
FIG. 5 shows a situation when rocking occurs in the upper structure 16 and the ground improvement body 19. In the figure, the vibration direction of the rocking is indicated by an arrow, and the upper part before the rocking occurs. The outline of the positions of the structure 16 and the lower structure 15 is indicated by a two-dot chain line.
[0032]
As shown in the figure, when the ground improvement body 19 is rocked, the foundation beam 22 is restrained by the foundation piles 20, 20,... And the surface ground 21 at a position away from the ground improvement body 19. Therefore, in this portion, there is only a slight displacement in the vertical direction.
[0033]
On the other hand, since the upper structure 16 is largely displaced in the vertical direction at a position away from the ground improvement body 19, naturally, the upper structure 16 and the foundation beam 22 are repeatedly separated and approached in the damper portion 25. Thus, the oil damper 30 acts to absorb the vibration energy of the upper structure 16.
[0034]
At this time, the clearance 31 functions to allow relative displacement between the floor slab 27 and the column 23. However, when the displacement of the upper structure 16 becomes excessive, the clearance between the floor slab 27 and the column 23 is reduced. Abut against each other and serve as a stopper, thereby preventing the upper structure 16 from being broken or overturned.
[0035]
As described above, the damping structure 13 is configured to positively lock the upper structure 16 and the ground improvement body 19 when horizontal vibration is applied during an earthquake. The entire 16 vibrates as a rigid body, and stresses more than necessary are not applied to the pillars and beams inside. Furthermore, since the vibration energy at this time is efficiently damped by the oil damper 30, the damping structure 13 can maintain safety during an earthquake.
[0036]
Moreover, in the damping structure 13, the ground improvement body 19 suppresses the deformation of the surface layer ground 21 due to an earthquake or a secular change, and stability is maintained.
[0037]
Further, in the damping structure 13, since the lower structure 15 includes the foundation piles 20, 20,..., Even when the upper structure 16 and the ground improvement body 19 vibrate, the foundation pile. Are not displaced, and the oil damper 30 interposed between the foundation piles 20, 20,... And the upper structure 16 can absorb vibration energy due to rocking well. Therefore, the safety of the vibration damping structure 13 is improved.
[0038]
In the lower structure 15, as shown in FIG. 2, the ground improvement body 19 is configured to be provided in a certain area when the lower portion of the upper structure 16 is viewed in plan view. By limiting the position of the contact portion between 19 and the support ground 18, the lower end portion 19 b of the ground improvement body 19 can be easily lifted from the support ground 18 and the ground improvement body 19 can be easily locked.
[0039]
Further, the foundation pile 20 is configured to be disposed around the ground improvement body 19, and the upper structure 16 and the ground improvement body 19 are rocked with the lower end edges 19 d and 19 d of the ground improvement body 19 as fulcrums. The position of the foundation pile 20 will be separated from the fulcrum. Therefore, in this case, the upper structure 16 repeats a large approach and separation in the vertical direction with respect to the foundation pile 20, whereby the oil damper interposed between the foundation pile 20 and the upper structure 16. 30, 30,... Can exhibit a great damping effect.
[0040]
Furthermore, in the damping structure 13, since the oil dampers 30, 30,... Are used as dampers for damping the vibrations of the upper structure 16 and the ground improvement body 19, the upper structure 16 and the ground improvement body 19 are used. Vibration is absorbed well, and the vibration damping performance of hardness is realized.
[0041]
In addition, in the said embodiment, as long as it is in the range which does not deviate from the main point of this invention, you may make it employ | adopt another structure about the structure of each part of the damping structure 13, etc. FIG.
[0042]
For example, as shown in FIG. 6, as the foundation pile 20 in the above embodiment, a friction pile whose lower end portion 20b does not reach the support ground 18 may be used instead of the support pile. Also in this case, at the time of an earthquake, the ground improvement body 19 and the upper structure 16 are locked together, and the same operation and effect as in the above embodiment can be obtained.
[0043]
Moreover, in the damping structure 13 shown in FIG. 6, it is suitable to comprise the damper part 25 and its vicinity as shown in FIG.
In FIG. 7, the foundation pile 20 is configured to pass through the foundation beam 22 and the floor slab 27 of the upper structure 16, and the upper end portion 20 a thereof is located above the foundation beam 22 and the floor slab 27. It is configured. Further, oil dampers 30 and 30 are provided between the upper end portion 20 a of the foundation pile 20 and the pillar 23, and hydraulic jacks (jacks) 33 and 33 are provided between the upper end portion 20 a and the floor slab 27. Is intervening.
[0044]
In the damping structure 13 shown in FIG. 6 and FIG. 7, since the foundation pile 20 is comprised from the friction pile, some foundation piles 20, 20, ... and the foundation supported by these foundation piles 20 are supported. As shown in FIG. 8, a part of the beams 22 is expected to be displaced downward with local settlement of the surface ground 21 due to the earthquake. In such a case, the inclination generated in the foundation beam 22 is corrected by driving the hydraulic jacks 33, 33 and taking the reaction force from the foundation piles 20, 20,. The position will be kept appropriate.
[0045]
In this way, by interposing the hydraulic jack 33 between the foundation pile 20 and the upper structure 16, even when a part of the foundation beam 22 is inclined due to the settlement of the surface ground 21, the inclination is reduced. It can correct | amend and can maintain the upper structure 16 in a healthy state. Furthermore, by correcting the position of the foundation beam 22 and making the relative position with the upper structure 16 appropriate in this way, it is possible to prevent the stroke limit of the oil damper 30 from being affected by an earthquake. Thus, the damping function of the damping structure 13 can be maintained even after an earthquake.
[0046]
Further, FIG. 9 shows support piles 35 and 35 that are placed in the ground so that the lower end portion 35a reaches the support ground 18 instead of the ground improvement body 19 used in the above-described embodiment and its surroundings. It is an example at the time of using the friction pile 36 provided in. In this case, the support piles 35 and 35 are integrated with the upper structure 16, and the lower ends 35a and 35a of the support pile 35 are alternately locked as fulcrums. Can be expected.
[0047]
Thus, by using the support pile 35 and the friction pile 36 instead of the ground improvement body 19, the mass of the lower structure 15 can be reduced and the damping function of the damping structure 13 can be enhanced.
[0048]
Further, in this case, since the placement position of the support pile 35 becomes the position of the fulcrum at the time of locking, the position of the fulcrum at the time of locking can be accurately known, and the vibration damping performance of the vibration damping structure 13 is previously Can grasp. In addition, the damping performance of the damping structure 13 can be adjusted by adjusting the placement position of the support pile 35.
[0049]
Further, the shape of the ground improvement body 19 in the above embodiment is not necessarily the one shown in FIG. 1, and the horizontal cross-sectional area of the contact portion between the lower end portion 19b and the supporting ground 18 is compared with that of the main body portion 19c. Anything that is small is acceptable. Therefore, for example, the ground improvement body 19 may be shaped like an inverted truncated pyramid.
[0050]
【The invention's effect】
As described above, the vibration damping structure according to claim 1 includes the upper structure and the support structure including the support structure and the underground structure. In the meantime, a damper is provided, and the lower end portion of the support structure is in contact with the support ground, and has two points that alternately serve as fulcrums when the support structure and the upper structure vibrate. It is said. Since the vibration damping structure of the present invention has such a configuration, when horizontal vibration acts during an earthquake, the upper structure and the support structure are actively locked, and the vibration energy is attenuated by the damper. Therefore, in the event of an earthquake, the stress inside the upper structure will not be applied to the columns and beams inside the upper structure, and the safety inside the upper structure will be maintained. . In particular, since the support structure is formed by a ground improvement body that is a part of the surface layer solidified, deformation of the surface layer due to an earthquake or secular change is suppressed, and the stability of the structure is maintained. It becomes.
[0051]
According to the vibration damping structure according to claim 2, since the support structure is composed of support piles that are placed in the ground so that the lower end of the support structure reaches the support ground, the mass of the lower structure Can be reduced and the damping function of the damping structure can be enhanced. Also, in this case, the placement position of the support pile as the support structure is the fulcrum when the upper structure and the support structure are locked, so the behavior of the support structure during an earthquake can be clarified. As a result, the vibration damping performance of the vibration damping structure can be grasped in advance. Moreover, the damping performance of the damping structure can be adjusted by adjusting the placement position of the supporting pile as the supporting structure.
[0052]
According to the damping structure according to claim 3, since the underground structure is composed of the foundation pile, the underground structure is displaced even when the upper structure and the support structure are locked. Therefore, at the time of an earthquake, the underground structure and the upper structure are repeatedly approached and separated from each other, and thereby, the damper interposed between the underground structure and the upper structure causes the locking. It becomes possible to absorb the vibration energy of the upper structure satisfactorily.
[0054]
In the vibration damping structure according to claim 4, when the lower part of the upper structure is viewed in plan, the support structure is provided in a certain region, so that the support structure and the support ground come into contact with each other. By limiting the position of the location, the lower end of the support structure can be easily lifted from the support ground, and when the support structure is locked, a large rotation angle can be obtained with a small moment. Further, in this vibration damping structure, since the underground structure is arranged around the support structure, the upper structure and the support structure are provided with a part of the lower end portion of the support structure as a fulcrum. When locked, the position of the underground structure is separated from the fulcrum, so the upper structure repeats a large approach and separation in the vertical direction with respect to the underground structure. It is possible to obtain a great vibration damping effect.
[0055]
In the vibration damping structure according to the fifth aspect , since the oil damper is used as the damper, the vibrations of the upper structure and the support structure are favorably absorbed, and the vibration damping performance of the vibration damping structure is improved. It is done.
[0056]
In the vibration damping structure according to claim 6 , since the jack is interposed between the underground structure and the upper structure, even when a part of the upper structure is inclined due to the settlement of the surface ground The inclination generated in the upper structure by taking the reaction force from the underground structure can be corrected. This not only helps to maintain the soundness of the superstructure after the earthquake, but also prevents the impact of the earthquake on the limit of the damper stroke and keeps the damping function after the earthquake properly. it can.
[Brief description of the drawings]
FIG. 1 is an elevational sectional view of a vibration damping structure schematically showing an embodiment of the present invention.
FIG. 2 is a plan sectional view showing a state below an upper structure in the vibration damping structure shown in FIG. 1;
3 is an elevational sectional view showing a state of a damper portion and its vicinity in the vibration damping structure shown in FIG. 1. FIG.
FIG. 4 is a graph showing the relationship between the moment and the rotation angle at the lower end of the ground improvement body, showing the action of the vibration damping structure of the present invention during an earthquake.
FIG. 5 is an elevational sectional view for illustrating the action of the vibration damping structure of the present invention during an earthquake.
FIG. 6 is an elevational sectional view of a vibration damping structure schematically showing another embodiment of the present invention.
7 is a vertical sectional view showing a state of a damper portion and its vicinity in the vibration damping structure shown in FIG . 6 ;
FIG. 8 is a diagram for illustrating the action at the time of land subsidence in the vibration control structure shown in FIG . 6;
FIG.
FIG. 9 is an elevational sectional view of a vibration damping structure schematically showing another embodiment of the present invention.
The
FIGS. 10A and 10B are views for showing a conventional technique of the present invention, in which FIG. 10A is an elevational sectional view showing a structure according to the conventional technique, and FIG. It is a plane sectional view for showing a lower structure.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Ground 13 Damping structure 15 Lower structure 16 Upper structure 18 Support ground 19 Ground improvement body (support structure)
19a upper end part 19b lower end part 19c body part 20 foundation pile (underground structure)
20a Upper end portion 21 Surface ground 25 Damper portion 30 Oil damper 33 Hydraulic jack
35 Support pile (support structure)
35a lower end

Claims (6)

Comprising a lower structure constructed on a support ground in the ground, and an upper structure supported by the lower structure;
The lower structure has a lower end abutting against the support ground, and an upper end fixed to the upper structure to support a central portion of the upper structure, and an upper end of the lower structure It is configured to include a peripheral structure of the upper structure and an underground structure connected via a damper,
The lower end of the support structure, when seen in sectional side view with at least one vertical plane, when the support structure and the upper structure is vibrated, has two points spaced apart in a horizontal direction as a fulcrum alternately It is supposed to
The support structure is composed of a ground improvement body obtained by consolidating a part of the surface ground located on the support ground, and a horizontal sectional area at a lower end portion of the ground improvement body is higher than a horizontal sectional area at an upper end portion. The lower end edge of the ground improvement body abuts on the support ground and serves as the fulcrum so that the support structure and the upper structure are locked when the support structure and the upper structure are vibrated to operate the damper; Damping structure characterized by being made. Comprising a lower structure constructed on a support ground in the ground, and an upper structure supported by the lower structure;
The lower structure has a lower end abutting against the support ground, and an upper end fixed to the upper structure to support a central portion of the upper structure, and an upper end of the lower structure It is configured to include a peripheral structure of the upper structure and an underground structure connected via a damper,
The lower end of the support structure, when seen in sectional side view with at least one vertical plane, when the support structure and the upper structure is vibrated, has two points spaced apart in a horizontal direction as a fulcrum alternately It is supposed to
The support structure includes a support pile placed in the ground so that a lower end portion thereof reaches the support ground, and the lower end portion of the support pile serves as the fulcrum, so that the support structure and A vibration damping structure characterized in that the damper is operated by locking them when the upper structure vibrates .   3. The vibration damping structure according to claim 1, wherein the underground structure includes a foundation pile placed in the ground. 4. 4. The vibration damping structure according to claim 1 , wherein the support structure is provided in a certain region when the lower portion of the upper structure is viewed in plan, and the underground structure A damping structure characterized in that a body is provided around the support structure 5. The vibration damping structure according to claim 1 , wherein the damper is an oil damper. 6. 6. The vibration damping structure according to claim 1 , wherein a vertical position of at least a part of the upper structure is adjusted between the upper structure and the underground structure. A damping structure characterized in that a jack is provided.

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