JP4431808B2 - Seismic isolation structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a seismic isolation structure that provides seismic isolation support for a high-rise upper structure, such as a bridge pier, a business building, an office building, and an apartment building.
[0002]
[Problems to be solved by the invention]
Various technologies have been proposed for isolating the upper structure by interposing the seismic isolation device between the upper structure and the lower structure such as the foundation. As the seismic isolation device, a rigid layer and rubber are usually used. A laminated rubber obtained by alternately laminating layers is used, and the rubber layer of the laminated rubber is integrated by vulcanization bonding to a steel plate constituting the rigid layer.
[0003]
In such a laminated rubber, since the load in the vertical direction (stacking direction) of the superstructure is applied to the laminated rubber, the steel plate is not subjected to lateral displacement due to an earthquake or wind, that is, in horizontal shear strain. And the rubber layer is not separated from each other, and the steel plate and the rubber layer are not separated, and the steel plate and the rubber layer that can withstand such lateral displacement force are not Obtaining mutual adhesion is not that difficult.
[0004]
By the way, a rotation moment in the fall direction (this is called a fall direction rotation moment in the present invention) also occurs in the superstructure due to an earthquake or wind pressure, but the aspect ratio (height / width ratio) is usually small. In the lower superstructure, the direction of the rotation moment in the reverse direction is opposite, and the rotation moment caused by its weight (this is called the return direction rotation moment in the present invention) cancels the rotation direction rotation moment, and the lower surface of the upper structure Although lifting on one side is prevented, in the upper structure with a large aspect ratio, which is usually high, the rotational torque in the fall direction is relatively larger than the rotational torque in the return direction, and the lower surface of the upper structure One side tries to float up. The magnitude of this rotational torque in the overturning direction is determined by the magnitude of the seismic acceleration or the magnitude of the wind pressure in addition to the magnitude of the aspect ratio. One side tries to float up.
[0005]
In the case of a superstructure with a large aspect ratio that does not use laminated rubber, this lifting force is received by anchor bolts, etc., to prevent the bottom side of the superstructure from lifting, but a superstructure with a large aspect ratio. When an object is to be seismically isolated with laminated rubber, the lifting force cannot be prevented by receiving the lifting force with an anchor bolt or the like, and the lifting force must be received with the laminated rubber. The adhesive strength between the steel plate and the rubber layer and the strength of the rubber layer in the laminated rubber that can withstand the almost vertical pulling force based on the lifting are required.
[0006]
And as the aspect ratio increases even with a small earthquake acceleration or low wind pressure, the vertical pulling force increases. Therefore, the adhesive force between the steel sheet and the rubber layer and the rubber layer enough to withstand such vertical pulling force. It is difficult to obtain a high strength, and usually, a superstructure having a high aspect ratio of 3 or more is formed by alternately laminating steel plates and rubber layers despite having extremely excellent characteristics. There is not much effort to seismically isolate with laminated rubber.
[0007]
In addition, regardless of the aspect ratio of the upper structure, the rubber layer of the laminated rubber may be compressed in the lamination direction due to the overturning rotational moment applied to the upper structure, which may cause the upper structure to lock. If such locking occurs and continues for a long time, the upper structure may be damaged, such as cracks, and the residents such as apartments may feel uneasy and uncomfortable.
[0008]
The present invention has been made in view of the above points, and the object of the present invention is to reduce the load of the lifting force of the superstructure on the seismic isolation device based on the falling direction rotational moment, It is intended to provide a seismic isolation structure that can reduce the tensile force in the stacking direction applied to the structure and, in addition, reduce the locking of the upper structure, and even if the locking occurs, can quickly attenuate it. .
[0009]
[Means for Solving the Problems]
The seismic isolation structure according to the first aspect of the present invention includes a pair of struts juxtaposed in a direction orthogonal to the bridge axis direction, and an upper and a lower lateral that bridge the pair of struts in a direction orthogonal to the bridge axis direction. A bridge pier as an upper structure having a member, a foundation or foundation as a lower structure, and a pier on the foundation or foundation interposed between the lower surface of each column of the pier and the upper surface of the foundation or foundation. In order to provide seismic isolation support, rigid layers and rubber layers are alternately stacked in the vertical direction, the upper end surface in the stacking direction is fixed to the lower surface of the column, and the lower end surface in the stacking direction is fixed to the upper surface of the base or foundation A pair of seismic isolation devices equipped with laminated rubber, one end part is connected to each column of the pier, and the other end part is rotatably connected to the foundation or foundation, respectively, and the bridge axis direction of the pier on the foundation or foundation Expansion and contraction to attenuate rocking in the direction perpendicular to A pair of existing dampers, and the dampers generate resistance to resist lifting from the base or foundation of the pier, and expand and contract during pier locking to absorb the rocking energy of the pier. It has become.
[0010]
According to the seismic isolation structure of the first aspect, the damper that connects the upper structure and the lower structure generates a resistance force against the lifting of the upper structure from the lower structure, and the upper structure Because the locking energy is absorbed by expanding and contracting in locking, a part of the lifting force of the superstructure based on the overturning direction rotational moment can be borne by the damper, and thus, the relief based on the overturning direction rotational moment can be applied. The pulling force in the stacking direction applied to the seismic device can be reduced, and even if the upper structure is locked, it can be quickly attenuated by the damper.
[0011]
The superstructure is a high-rise superstructure, and preferably has an aspect ratio of 3 or more, and can be exemplified by a business building, an office building, or an apartment building. Although what has the height more than a meter can be mentioned, it is not specifically limited to these.
[0012]
As the seismic isolation device, it is preferable to include one having a laminated rubber in which rigid layers and rubber layers are alternately laminated in the vertical direction as described above. (Lead struts) may be embedded. In short, the upper structure can exhibit a seismic isolation function, but may be any seismic isolation device including a laminated rubber that causes rocking.
[0013]
In a preferred example, the damper has a friction damping history characteristic, and also includes a cylinder, a piston that defines an interior of the cylinder in two chambers, and an orifice that communicates the two chambers with each other, and a cylinder A cylinder, a cylinder, a rod having an enormous portion inside the cylinder, and penetrating both ends of the cylinder, and an inside of the cylinder And lead filled.
[0014]
In the present invention, examples of the substructure may include the above-described foundation or foundation formed on the ground, but other structures may be used as a reference.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention and its embodiments will be described in more detail with reference to preferred examples shown in the drawings. The present invention is not limited to this example.
[0016]
1 and 2, the seismic isolation structure 1 of this example is interposed between a bridge pier 2 as an upper structure, a foundation 3 as a lower structure, and a pier 2 and a foundation 3, so that the foundation 3 A laminated rubber 4 serving as a seismic isolation device for supporting the pier 2 in a seismic isolation manner, a first end 5 is connected to the pier 2, and the other end 6 is rotatably connected to the foundation 3. And a damper 7 that can be expanded and contracted in the A direction for attenuating rocking in the R direction, which is a direction orthogonal to the bridge axis direction.
[0017]
The pier 2 of this example has a height of 6 meters or more, an aspect ratio of 3 or more, and a pair of support columns 11 juxtaposed in a direction orthogonal to the bridge axis direction, and the support columns 11 in the direction of the bridge axis. The upper and lower lateral members 12 and 13 and the braces 14 and 15 that bridge each other in the direction orthogonal to the upper side support the bridge girder 16 placed on the upper side. An attachment member 17 for rotatably connecting one end portion 5 of the damper 7 is fixed to each of the pair of struts 11 by welding or anchor bolts.
[0018]
The concrete foundation 3 is fixed to a ground (not shown) by a pile or the like and is installed on the ground. An attachment member 18 for rotatably connecting the other end 6 of the damper 7 to the foundation 3. Are fixed by anchor bolts or the like.
[0019]
Each of the laminated rubber 4 provided on each of the pair of support columns 11 includes a laminated rubber main body 21 and upper and lower attachment plates 22 and 23 attached to the upper and lower surfaces of the laminated rubber main body 21. The rubber body 21 is formed by alternately laminating steel plates and rubber layers constituting a rigid layer in the vertical direction. The steel plates and the rubber layers are bonded to each other by vulcanizing and bonding the rubber layers to the steel plates. Each of the upper and lower mounting plates 22 and 23 is vulcanized and bonded to the rubber layer of the laminated rubber body 21, or together with this, bolts are attached to the uppermost and lowermost steel plates of the laminated rubber body 21. And so on. Each of the laminated rubbers 4 is fixed to the upper surface 25 of the foundation 3 with the lower surface 24 of the lower mounting plate 23 via an anchor bolt or the like. The upper surface 26 of the upper mounting plate 22 is fixed to the lower end surface 27 of the corresponding column 11. Each laminated rubber 4 is interposed between the lower surface of each column 11 and the upper surface 25 of the foundation 3 to support the pier 2 on the foundation 3 in a seismic isolation manner. As described above, the rigid layers and the rubber layers are alternately stacked in the vertical direction, and the upper end surface in the stacking direction is fixed to the lower surface of the support column 11 and the lower end surface in the stacking direction is fixed to the upper surface 25 of the foundation 3.
[0020]
Each of the dampers 7 provided on each of the pair of support columns 11 includes a cylinder 33 whose both end faces are closed by a closing member 31 and a closing part 32 as a closing part, and the inside of the cylinder 33 is defined in two chambers 34 and 35. In addition, a piston 37 having an orifice 36 communicating with the two chambers 34 and 35, a silicon-based fluid 38 filled in the two chambers 34 and 35, and the closing member 31 and the closing portion 32 are slid in the A direction. The piston rod 39 is fixed to the one end of the cylinder 33, and the mounting member 41 is fixed to one end of the piston rod 39. The attachment member 41 is rotatably connected to the attachment member 17 via the shaft member 42, and the attachment member 41 is rotatably connected to the attachment member 18 via the shaft member 43. Are, thus, the damper 7, the post 11 of one end portion 5 is pier 2, the other end 6 is pivotally connected to the respective R direction to the base 3.
[0021]
Each of the dampers 7 expands and contracts in the A direction, so that the piston 37 is moved in the A direction inside the cylinder 33. By this movement, the fluid 38 enters and exits the two chambers 34 and 35 through the orifice 36. As shown by the curve 50, the friction damping history characteristic is equivalently exhibited. For example, the friction damping history of the initial tension and elongation shows a tensile force of a certain level or more as shown by the curve 51. In addition, elongation is only occurring for the first time. In addition, each of the dampers 7 has a rotation direction rotation moment so that a tensile force greater than the maximum tensile strength in the stacking direction is not applied to the corresponding laminated rubber 4 when an R direction rotation direction rotation moment is generated on the pier 2. It is designed to receive the pulling force based on.
[0022]
In the above example, assuming that the swing of the pier 2 occurs only in the R direction, the one end 5 and the other end 6 of the damper 7 are respectively turned around the pier 2 and the foundation 3 via the shaft members 42 and 43, respectively. If the bridge pier 2 swings in the direction perpendicular to the plane of FIG. 1 including the R direction, that is, also in the bridge axis direction, the one end 5 and the other end of the damper 7 are connected. 6 may be rotatably connected to the pier 2 and the foundation 3 via ball joints or the like.
[0023]
In the seismic isolation structure 1 described above, the bridge pier 2 is supported on the foundation 3 via the laminated rubber 4, and when the foundation 3 vibrates in the horizontal direction due to the earthquake, the laminated rubber 4 is sheared elastically deformed in the horizontal direction. Thus, the transmission of the horizontal vibration of the foundation 3 to the pier 2 is reduced, and the earthquake vibration is isolated.
[0024]
In the seismic isolation structure 1, when an R orienting rotation moment in the R direction is generated on the pier 2 due to an earthquake or a wind, the damper 7 resists lifting of the pier 2 from the foundation 3 based on the overturning direction rotation moment. To prevent the bridge pier 2 from swinging in the R direction.
[0025]
Further, in the seismic isolation structure 1, the rubber layer 4 is elastically expanded and contracted in the stacking direction, and a large turning direction rotational moment is applied to the pier 2 so as to expand and contract the damper 7 in the A direction. When the rocking occurs, the rocking energy is absorbed by the frictional damping history characteristic of the damper 7 as shown by the curve 50 so that the rocking is attenuated early.
[0026]
As described above, according to the seismic isolation structure 1, the damper 7 that connects the pier 2 and the foundation 3 generates a resistance force against the lifting of the pier 2 from the foundation 3, and the pier 2 is locked in the R direction. Since the rocking energy is absorbed by expanding and contracting in the A direction, a part of the lifting force of the bridge pier 2 based on the overturning direction rotational moment can be borne by the damper 7, and thus based on the overturning direction rotational moment. The pulling force in the laminating direction applied to the laminated rubber 4 can be reduced, and even if the pier 2 is locked, it can be attenuated early by the damper 7.
[0027]
In the seismic isolation structure 1 described above, the damper 7 including the piston 37 formed with the orifice 36 and the fluid 38 filled in the two chambers 34 and 35 is used. Such a damper 61 may be used. The damper 61 penetrates the cylinder 33, the closing member 31 and the closing portion 32 slidably in the A direction, and has a rod 63 having a huge portion 62 inside the cylinder 33 and the inside of the cylinder 33. Lead 64, the attachment member 40 fixed to the cylinder 33, and the attachment member 41 fixed to one end of the rod 63. The other end portion 6 is connected to the pier 2 so as to be freely rotatable.
[0028]
As the damper 61 expands and contracts in the A direction, the enormous portion 62 of the rod 63 is moved in the A direction inside the cylinder 33, and the lead 64 flows inside the cylinder 33 due to this movement, so that the curve 50 in FIG. As shown in the curve 51, for example, the friction damping history of the initial tension and elongation is not increased until a certain amount of tensile force is applied. Has come to occur. Similarly to the damper 7, the damper 61 is configured so that when a falling rotational moment in the R direction is generated on the pier 2, the corresponding laminated rubber 4 is not applied with a tensile force exceeding the maximum tensile strength in the lamination direction. It is designed to receive the tensile force based on the rotation moment in the falling direction.
[0029]
Even in the seismic isolation structure 1 using such a damper 61, a part of the lifting force of the pier 2 based on the overturning direction rotational moment can be borne by the damper 61, and thus added to the laminated rubber 4 based on the overturning direction rotational moment. The tensile force in the stacking direction can be reduced, and even if the pier 2 is locked, it can be attenuated early by the damper 61.
[0030]
【The invention's effect】
According to the present invention, it is possible to reduce the load of the lifting force of the upper structure on the seismic isolation device based on the falling direction rotational moment, to reduce the tensile force in the stacking direction applied to the seismic isolation device, and in addition to the upper structure It is possible to provide a seismic isolation structure that can reduce the rocking of the vehicle and can attenuate the rocking at an early stage even if the rocking occurs.
[Brief description of the drawings]
FIG. 1 is a front view of an example of a preferred embodiment of the present invention.
FIG. 2 is a cross-sectional view of the example damper shown in FIG. 1;
FIG. 3 is a characteristic curve diagram of an extension amount and a contraction amount-tensile force and a contraction force of the damper of the example shown in FIG. 1;
FIG. 4 is a front view of another example of a preferred embodiment of the present invention.
[Explanation of symbols]
1 Seismic isolation structure 2 Bridge pier 3 Foundation 4 Laminated rubber 7 Damper

Claims (3)

  A pair of struts juxtaposed in a direction orthogonal to the bridge axis direction, a bridge pier as an upper structure comprising an upper part and a lower lateral member that bridge the pair of struts in a direction orthogonal to the bridge axis direction; A rigid layer and a rubber layer are interposed between the lower surface of the foundation or foundation as a substructure and the lower surface of each support of the pier and the upper surface of the foundation or foundation so that the pier is isolated from the base or the foundation. A pair of seismic isolation devices that are laminated alternately in the vertical direction and have laminated rubber in which the upper end surface in the laminating direction is fixed to the lower surface of the support and the lower end surface in the laminating direction is fixed to the upper surface of the base or foundation; A pair of telescopic members, one end of which is pivotally connected to each support of the bridge pier and the other end is pivotally connected to the foundation or foundation, respectively, to attenuate rocking in the direction perpendicular to the bridge axis direction of the bridge pier on the foundation or foundation. Equipped with a damper The damper is configured to generate a resistance force against the floating of the base or foundation of piers, seismic isolation structure expands and contracts in the locking piers adapted to absorb locking energy of the piers.   The damper is composed of a cylinder, a piston that defines the inside of the cylinder in two chambers and an orifice that communicates the two chambers with each other, a fluid that fills the two chambers inside the cylinder, and the piston. The seismic isolation structure according to claim 1, further comprising: a piston rod penetrating the both-end closed portion of the cylinder.   The damper includes a cylinder, a huge portion inside the cylinder, a rod penetrating the both-end closed portion of the cylinder, and lead filled in the cylinder. The seismic isolation structure described in 1.

Images