JP2001182371A - Installation method for seismic isolator to base isolation steel tower and existing steel tower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an installation method for a base isolation type steel tower and existing steel tower capable of effectively improving the resistance against earthquake even for an existing steel tower. SOLUTION: A seismic isolator 10 is installed between each leg portion 5 of a steel tower 2 and a roof top of a building 1, each isolation device 10 is constituted with a slide mechanism 13 permitting the relative displacement in almost horizontal direction for the upper plate member 11 and the lower plate member 12, a vibration absorption and restoring mechanism 14 for lengthening the period of steel tower by giving a vibration and absorption mechanism absorbing the displacement energy and the restoring force, and further an upper displacement restricting mechanism which restricts the separation of more than a predetermined setting in up-down direction between the upper plate member 11 and the lower plate member 12. Moreover, the upper plate member 11 side and the lower plate member 12 side are connected each other by a shear pin 42 which does not cause a rupture until a force higher than the predetermined set value acts in the horizontal direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic isolation type tower suitable for application to, for example, a tower provided for communication or the like and a method of installing a seismic isolation device on an existing tower.

[0002]

2. Description of the Related Art In recent years, in buildings such as buildings, various types of seismic isolation devices and vibration damping devices have been incorporated in order to enhance the seismic performance, and the building itself has a seismic isolation / damping structure. The techniques used are often used.

[0003] By the way, in fact, a steel tower provided with a seismic isolation device or the like like the above-mentioned building has not been found in a steel tower provided for communication or the like.

[0004]

However, it is needless to say that it is desirable to improve the seismic performance of a steel tower as in the case of a building or the like. In particular, as shown in FIG. 12, in the tower 2 installed on the roof of the building 1 or the like, when the natural frequency of the building 1 and the natural frequency of the tower 2 are close to each other, the vibration generated in the building 1 when an earthquake occurs. Can amplify the vibration of the rooftop tower 2 and cause the vibration at the tower top 2a to have a very large amplitude. For this reason,
As described above, in the steel tower 2 installed on the roof of the building 1 or the like, it is desirable to immediately take measures for improving the earthquake resistance.

[0005] By the way, in order to improve the seismic performance of a steel tower, it is conceivable to incorporate a seismic isolation device into the steel tower as in the case of a building, but there are circumstances different from a building in a steel tower. First, the tower is, for example, 50m-100m
Etc., but the weight is less than 100 tons and most of them are lightweight. For this reason, in the event of a strong earthquake or typhoon, a force greater than its own weight acts on each leg in response to an external force trying to defeat the tower, and a force is generated to pull the leg upward. For this reason, even if various devices and the like are to be incorporated into the legs of a steel tower, simply incorporating a seismic isolation device such as a laminated rubber that has been conventionally applied to buildings and the like cannot withstand the force.

Further, as shown in FIG. 13, similarly to the conventional countermeasures for buildings and the like, a so-called tuned mass damper (hereinafter abbreviated as “TMD”).
Although it is conceivable to incorporate 3 or the like into the top of the tower 2,
The MD 3 is provided with a weight for canceling the vibration of the steel tower 2 due to an earthquake or the like. For example, in the case of a steel tower of about 50 to 100 m, this weight has a weight of about 10 t. It is known that an acceleration of about 2 G acts upon an earthquake or the like, and a very large force acts on the steel tower 2 by such a weight. However, as is well known, most of the steel towers 2 have a truss structure, so that the necessary minimum strength is secured and the weight of the steel tower 2 itself is reduced. On the other hand, as described above, TM
When D3 or the like is installed at the top of the tower, the strength of the tower 2 itself must be improved so as to withstand a large force acting upon the occurrence of an earthquake. As a result, the weight of the tower 2 increases, and the cost increases. There is a problem of inviting.

[0007] In addition, even for existing steel towers, it is the same that improvement in seismic performance is desired. However, it can easily be imagined that the construction itself is difficult even if the seismic isolation device is installed at the base of the tower. The present invention has been made in consideration of the above points, and a method of installing a seismic isolation type tower capable of effectively improving seismic resistance even with an existing steel tower and a seismic isolation device on the existing steel tower The task is to provide

[0008]

Means for Solving the Problems The invention according to claim 1
A seismic isolation device is interposed between each leg of the tower having a plurality of legs and a lower structure supporting the tower, and the seismic isolation device is fixed to the leg side. An upper base member, a lower base member fixed to the lower structure side, and a lower base member provided between the upper base member side and the lower base member side. A vibration absorbing mechanism that absorbs energy, a restoring mechanism that gives restoring force to lengthen the period of the tower, and an upper displacement restraining mechanism that restrains the upper base member and the lower base member from being separated from each other by a predetermined value or more in a vertical direction. And is provided.

As a result, during an earthquake or the like, for example, a relative displacement in a substantially horizontal direction occurs due to vibration between a lower structure such as a foundation or a building supporting a tower and each leg of the tower, and when the cycle of the tower becomes longer, In addition, the tower does not follow the movement of the lower structure, and the vibration of the tower can be suppressed. At the same time, the relative displacement energy is absorbed by the vibration absorbing mechanism, and the vibration of the tower can be further reduced. In addition,
Although the pulling force of each leg during an earthquake is reduced by reducing the tower vibration, the upper displacement member restrains the upper base member and the lower base member from separating from each other by a predetermined value or more in the vertical direction. Even in the case of a powerful earthquake, each leg does not rise. This also makes it possible to withstand a force in the direction in which each leg is pulled out even in a strong typhoon or the like.

The invention according to claim 2 is characterized in that the vibration absorbing mechanism and the restoring mechanism connect the upper base member and the lower base member so as to be relatively movable in a substantially horizontal direction; A viscous or hysteretic damper member provided between the upper base member and the lower base member, the damper member exhibiting a damping force with respect to the relative displacement in the substantially horizontal direction, provided between the upper base member and the lower base member. And a restoring force applying member that applies a restoring force to the relative displacement and lengthens the period of the tower.

As described above, the upper base member and the lower base member are connected by the slide mechanism so as to be relatively movable in a substantially horizontal direction, and when an earthquake or the like occurs, the relative displacement of both is attenuated by the damper member. By, for example, applying a restoring force with a restoring force applying member made of an elastic material such as a spring, the tower cycle can be adjusted to a longer cycle side.
Both can be restored to their original positions after the earthquake.

The invention according to claim 3 is characterized in that the slide mechanism is constituted by a slide bearing, and a damping force for a relative displacement between the upper base member and the lower base member is applied by a frictional force. And

According to a fourth aspect of the present invention, in the seismic isolation type tower according to the second aspect, as the upward displacement restraining mechanism, the sliding mechanism includes an upper sliding member on the upper base member side and the upper sliding member. A lower slide member on the side of the lower base member connected to the member so as to be slidable in a substantially horizontal direction, and a lateral slide is applied to one of the upper slide member and the lower slide member. A projecting engagement projection is provided, and on the other hand,
It is characterized in that an engaging concave portion for engaging with the engaging convex portion is provided.

The vertical displacement of the upper slide member and the lower slide member is restrained by engaging the engagement protrusion projecting laterally into the engagement recess.

According to a fifth aspect of the present invention, the vibration absorbing mechanism and the restoring mechanism are provided between the upper base member and the lower base member, a rigid plate made of a metal material and an absorbing layer made of a viscoelastic material. Are alternately stacked over a plurality of upper and lower layers.

As described above, seismic isolation performance can be imparted to a steel tower by using a so-called laminated rubber or the like as the vibration absorbing mechanism.

According to a sixth aspect of the present invention, as the upper displacement restraining mechanism, an upper portion extending toward the lower base member toward the upper base member and restraining the upward displacement of the upper base member is provided. It is characterized in that a displacement restraining member is provided.

With such an upper displacement restricting member, the upper and lower slide members are restricted from being displaced in the vertical direction.

According to a seventh aspect of the present invention, the upper base member side and the lower base member side are connected to each other by a horizontal displacement restraining member that does not break until a predetermined horizontal force is applied. Characterized in that the relative displacement in the substantially horizontal direction is restricted.

Thus, in a normal state, that is, in a state where the force acting on the horizontal displacement restraining member does not break below a predetermined set value, the upper base member side and the lower base member side are connected to each other by the horizontal displacement restraining member. As a result, a rigid structure is obtained in which the relative displacement between the two is restricted. In other words, the seismic isolation device is rigid and does not operate in a strong wind or an earthquake with a strength lower than the assumed strength. When the force acting on the horizontal displacement restraining member becomes equal to or greater than a predetermined value due to the relative displacement between the upper base member side and the lower base member side due to a strong earthquake or the like, the horizontal displacement restraining member Breaks. Thereby, the restraint in the horizontal direction between the upper base member side and the lower base member side is released, the relative displacement of both is permitted, and the vibration of the steel tower is suppressed by the seismic isolation device.

The invention according to claim 8 is characterized in that a leg connecting member for connecting the plurality of legs to each other is provided.

This makes it possible to suppress the relative displacement between a plurality of legs during an earthquake, when installing a seismic isolation device, or the like.

The invention according to claim 9 is characterized in that the tower is installed on a building as the lower structure.

As described above, by applying the present invention to a tower installed on a building, vibration of the tower on the building can be effectively suppressed.

According to a tenth aspect of the present invention, there is provided a method for installing a seismic isolation device on each of a plurality of legs of an existing steel tower, wherein a flange member projecting outward is attached to a lower end of the legs. After that, a temporary support jack is installed between the lower structure supporting the tower and the flange member, and subsequently, a portion below the flange member is cut off at the leg portion, and the flange member and the lower structure are cut off. In this case, the seismic isolation device according to any one of claims 1 to 9 is inserted, and then the temporary support jack is removed.

Thus, the above-mentioned seismic isolation device can be installed even on an existing steel tower, and as a result, the earthquake resistance of the steel tower can be effectively improved.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a seismic isolation type tower according to the present invention and a method of installing a seismic isolation device on an existing tower will be described below with reference to FIGS. here,
The present invention will be described using an example in which the present invention is applied to an existing steel tower installed on a building, for example. In the following description, portions common to FIGS. 12 and 13 shown as conventional examples are denoted by the same reference numerals.

FIG. 1 and FIG. 2 show a completed state of a seismic isolation type steel tower constructed by applying the method of installing a seismic isolation device to an existing steel tower according to the present invention. In this figure, reference numeral 1 denotes a building (lower structure, building), 2 denotes a tower installed on the roof of the building 1 and has a height of, for example, about 50 to 100 m, 5 denotes a leg of the tower 2, and 10 denotes a tower 2 This is a seismic isolation device installed between the building and the roof of Building 1.

Here, the steel tower 2 has a plurality of legs 5, for example, four legs, and the seismic isolation device 10 includes a lower end flange (flange member) 6 provided at each lower end of the legs 5.
(See FIG. 2) and the roof surface of the building 1. And as shown in FIG. 1, these legs 5
At its lower end, horizontal connecting members (leg connecting members) 7,
Are connected to each other by 7,.

As shown in FIG. 2, each seismic isolation device 10
An upper plate member (upper base member) 11 integrally fixed to the lower surface of the lower end flange 6 of the leg portion 5, a lower plate member (lower base member) 12 integrally fixed to the roof of the building 1 with anchor bolts or the like; These upper plate members 1
1 and a lower plate member 12, a slide mechanism 13, a vibration absorbing / restoring mechanism (vibration absorbing mechanism, restoring mechanism) 14, and a trigger mechanism 15.

As shown in FIG. 3, the slide mechanism 13
It is composed of two sets of slide rails 20X and 20Y that are slidable in two mutually perpendicular XY directions. The slide rails 20X, 20Y are respectively composed of a pair of bases 21X, 21Y parallel to each other and bases 21X, 21Y.
Rail member (lower slide member) 22X, rail member (upper slide member) 2 laid on each of 1Y
2Y. And each rail member 22
X and 22Y are provided with slide saddles 23X and 23Y, respectively, so as to be slidable. Here, the rail members 22X, 22Y and the slide saddles 23X, 23
6 shows an engagement structure with Y. As shown in FIG. 4, the slide saddle 23 </ b> X is covered with the rail member 22 </ b> X.
A concave groove 24 is formed on the lower surface side. This groove 24
Between bearing and slide saddle 23X, bearing ball train 2
5 is held, and thereby, the slide saddle 23
X can move smoothly along the rail member 22X.

Further, as an upward displacement restraining mechanism for restraining the displacement in the vertical direction, engaging recesses 26 having a substantially arc-shaped cross section are continuously formed on both side surfaces of the rail member 22X. Engaging projections 27, 27 having a substantially arc-shaped cross section corresponding to the engagement recesses 26, 26 are continuously formed on both inner side surfaces of the concave groove 24 of 23X. The engagement recesses 26, 26 and the engagement protrusions 27, 27 are engaged with each other, whereby the rail member 22X and the slide saddle 23 are engaged.
X has a structure in which displacement in the vertical direction is firmly restrained. Although FIG. 4 is a cross-sectional view in the direction showing the engagement portion between the rail member 22X in the X direction and the slide saddle 23X, the engagement structure between the rail member 22Y in the Y direction and the slide saddle 23Y is also described. The engagement structure is the same as that in the X direction, and the description is omitted here.

The base 21Y of the Y-direction slide rail 20Y is integrally fixed to the upper surface of each slide saddle 23X of the X-direction slide rail 20X. Further, a saddle plate 28 is integrally provided on the upper surface of each slide saddle 23Y of the slide rail 20Y in the Y direction. Such a slide mechanism 13
The bases 21X and 21X of the slide rail 20X are integrally fixed to the lower plate member 12, and the saddle plate 28
Are integrally fixed to the upper plate member 11. Accordingly, in the slide mechanism 13 including the XY two-direction slide rails 20X and 20Y, the upper plate member 11 and the lower plate member 12 can be relatively moved in any direction in a substantially horizontal plane, and can be displaced in the vertical direction. On the other hand, it is configured to be tightly restrained.

As shown in FIG. 2, the vibration absorbing / restoring mechanism 14 includes an upper plate member 11 and a lower plate member 12.
, A damper member 30 such as a hydraulic damper provided on each of four outer peripheral portions of the slide mechanism 13.
And a spring member such as a coil spring (restoring force applying member)
31. The damper member 30 and the spring member 31 are provided between an upper bracket 32 projecting downward from a lower surface of the upper plate member 11 and a lower bracket 33 projecting upward from the lower plate member 12, respectively. A total of four sets of damper members 30 and spring members 31 arranged on four sides of the slide mechanism 13 are such that two sets effectively act on displacement in the X direction and two sets on the substantially horizontal direction in the Y direction. I have.

In such a vibration absorbing mechanism 13, the upper plate member 11 and the lower plate member 12 are displaced in a direction in which the upper bracket 32 and the lower bracket 33 approach and separate from each other due to the relative displacement between the upper plate member 11 and the lower plate member 12 in a substantially horizontal direction. Sometimes, the damper member 30 absorbs the displacement energy, the spring member 31 lengthens the period of the tower, and provides a restoring force for returning the upper bracket 32 and the lower bracket 33 to their original positions after the earthquake. I do. Thereby, the relative displacement in the substantially horizontal direction between the upper bracket 32 and the lower bracket 33, in other words, the upper plate member 11 and the lower plate member 12 is effectively controlled.

The trigger mechanism 15 includes the upper plate member 1
An upper bracket 40 integrally attached to the outer surface of the lower plate member 1 and extending downward, a lower bracket 41 integrally provided on the outer surface of the lower plate member 12 and protruding, and the upper bracket 40 and the lower bracket 41 are combined. And a shear pin (horizontal displacement restricting member) 42 to be connected. The shear pin 42 has a predetermined strength set in advance in the shear direction, and
0 and the lower bracket 41 are connected to each other by being horizontally inserted into insertion holes (not shown) formed in the lower bracket 41, respectively.

The upper plate member 1 is attached to the shear pin 42.
1 and the lower plate member 12 attempt to displace in a substantially horizontal direction, the upper bracket 40 and the lower bracket 4
1 causes a substantially horizontal shear force to act. Then
The shear pin 42 does not break until the acting shear force reaches a predetermined value. In this state, the upper bracket 40 and the lower bracket 41 are restrained, that is, the relative movement between the upper plate member 11 and the lower plate member 12 is restrained, The seismic isolation device 10 is in a rigid (fixed) state. When the shear force acting on the shear pin 42 becomes equal to or more than a predetermined value, the shear pin 42 is broken, and as a result, the restraint of the upper bracket 40 and the lower bracket 41 is released, and the upper plate member 1
1 and the lower plate member 12 can be relatively displaced in a substantially horizontal direction by the slide mechanism 13.

In the present embodiment, such a trigger mechanism 15 is provided on two mutually adjacent side surfaces of the seismic isolation device 10, whereby it is possible to exert its restraining force in the two XY directions. ing. It should be noted that by setting the shear pin of the trigger mechanism vertically, it is also possible to exert binding force in two directions of XY with one.

In the normal state, the steel tower 2 in which the seismic isolation device 10 having such a structure is installed on each leg 5 is in a rigid state in which the horizontal displacement is restricted by the trigger mechanism 15. As a result, it is fixed to the building 1 even against strong winds. When a shear force of a predetermined value or more acts on the shear pin 42 of each trigger mechanism 15 due to a strong earthquake or the like, the shear pin 42 breaks,
The restriction between the upper plate member 11 and the lower plate member 12 is released. Then, in the seismic isolation device 10,
A substantially horizontal relative displacement occurs between the building 1 side vibrated by the earthquake and each leg 5 side of the steel tower 2, and the vibration energy is attenuated and absorbed by the damper member 30 of the vibration absorbing / restoring mechanism 14. As a result, vibration of the tower 2 can be effectively suppressed. At this time, even if the original natural period of the tower 2 is close to the natural period of the building 1, the natural period of the tower 2 is extended by the spring member 31,
A phase difference of about 180 ° occurs between the swing of the building 1 and the swing of the tower 2, and the swing of the tower 2 does not follow the swing of the building 1. At this time, the displacement in the vertical direction is restrained by the engagement between the engaging concave portions 26, 26 of the slide mechanism 13 and the engaging convex portions 27, 27, and the force is such that the leg 5 of the steel tower 2 rises. It is possible to withstand strong against. Further, since the plurality of legs 5 of the steel tower 2 are connected to each other by the horizontal connecting members 7, 7,..., The legs 5, 5,. Further, the plurality of legs 5 can be integrally displaced.

FIGS. 5 and 6 show the results of an earthquake response analysis for comparison between the steel tower 2 incorporating the seismic isolation device 10 having the above-described configuration and a conventional steel tower. is there. Here, "No countermeasure" indicates a model of a tower (see FIG. 12) for which no countermeasure was taken.
The model referred to as “TMD” is a model in which the TMD is installed on the top of the tower (see FIG. 13), and the model referred to as “seismic isolation (measures by)” is a tower incorporating the seismic isolation device 10 described above. 2 is a model. The specifications of the tower itself are common in each model, height: 46.8 m, top width:
5.5 m, base opening: 14.4 m, weight: 154 t. The building (building) on which the steel tower is built on the roof has a height of 12.3 m and a weight of 2650 t. Also,
The “TMD” model is a model in which a mass having a weight of 10 t is installed.

As a result of the natural vibration analysis of each of the three models as described above, "no countermeasures" were obtained: primary frequency = 1.402 Hz, secondary frequency = 1.679 Hz "TMD": primary vibration Number = 0.757 Hz, Secondary frequency = 1.340 Hz “Seismic isolation”: Primary frequency = 0.327 Hz, Secondary frequency = 1.677 Hz. In addition, the seismic response analysis includes El Centro NS waves,
Maximum input acceleration: 510.8 Gal (50 cm / s),
Input position: building base
As shown in each figure.

As shown in the graph of FIG. 5, in the seismic isolation type tower 2, the horizontal relative displacement at the tower top height due to external force is reduced to about 1/4 as compared with the case of the tower with TMD. In addition, as shown in the graph of FIG. 6, it can be seen that the absolute acceleration accompanying the vibration in the tower 2 is reduced to about 1/3 as compared with the case of the tower with TMD. Thus, it is clear that the tower 2 provided with the seismic isolation device 10 has the effect of significantly reducing the amplitude and significantly reducing the inertial force acting on the tower during an earthquake, that is, the seismic force.

In addition, the reaction force acting on the base of the tower at that time is, as shown in Table 1, in the tower 2 provided with the seismic isolation device 10, the horizontal reaction force per one leg 5 is: TMD
The vertical reaction force per leg 5 is reduced to about 1/8 compared to the tower with TMD, and about 1/8 compared to the tower with TMD.

[0044]

[Table 1]

In addition, the maximum amplitude of the "TMD" model was 49 cm (maximum acceleration: 2116 Gal), and the maximum relative displacement of the "seismic isolation" model was 17 cm.

By the way, in order to install the seismic isolation device 10 as described above on an existing steel tower 2, first, as shown in FIG. Building 1
A lower end flange 6 that protrudes outward is integrally attached to a position at a predetermined height from the roof top surface by welding or the like. Note 8
Is a reinforcing web of the lower end flange 6. Next, a plurality of temporary support jacks 50 are arranged between the outer peripheral portion of the lower end flange 6 and the roof surface of the building 1, and each is extended to support the lower end flange 6.

Subsequently, as shown in FIG.
Of the leg portion 5, a portion 5 a below the lower end flange 6 is cut off. Then, as shown in FIG. 7 (c), after inserting and installing the seismic isolation device 10 in the cut off portion, each temporary support jack 50 is contracted, and the load of the lower end flange 6 is applied to the upper plate member 11 of the seismic isolation device 10. Multiply. After a while, FIG. 7 (d)
As shown in (2), by removing each temporary support jack 50, the installation of the seismic isolation device 10 on the leg 5 is completed.

The seismic isolation device 10 is constructed by sequentially or simultaneously installing the seismic isolation devices 10 on the legs 5 in the above-described manner.

In the seismic isolation type tower 2 described above, when an earthquake occurs,
When the vibration causes a substantially horizontal relative displacement between each leg 5 of the tower 2 and the roof of the building 1, the period of the tower is extended by the restoration mechanism, and the tower does not follow the swing of the building. Further, the relative displacement energy is absorbed by the vibration absorbing / restoring mechanism 14, and the vibration of the steel tower 2 can be further reduced. As a result, the seismic performance of the tower 2 installed on the building 1 can be effectively improved, and the reaction force acting on the building 1 from the tower 2 can be reduced.

Further, the upper plate member 11 and the lower plate member 1 are moved by the upper displacement restricting mechanism provided by the engagement between the engaging concave portion 26 and the engaging convex portion 27 provided in the slide mechanism 13.
2 is restrained in the vertical direction from being separated by a predetermined value or more, whereby it is possible to withstand a force in the direction of pulling out each leg 5 acting upon a strong earthquake or typhoon. . As a result, it is possible to prevent the leg portion 5 of the steel tower 2 from being lifted up due to the vertical displacement of the seismic isolation device 10.

In addition, since the upper plate member 11 and the lower plate member 12 are connected to each other by the shear pin 42, the seismic isolation device 10 can be moved in the horizontal direction in a strong wind or an earthquake having a strength less than the assumed strength. And the seismic isolation device does not operate. Then, when the shear pin 42 breaks due to a force greater than a predetermined set value due to a strong earthquake or the like, the restraint in the horizontal direction between the upper plate member 11 and the lower plate member 12 is released, and both of them are released. Relative displacement is allowed, and the tower period becomes longer. At the same time, the vibration absorbing / restoring mechanism 14 exerts a damping force for suppressing the vibration of the tower 2. Providing the sheer pin 42 in this manner is effective for a strong earthquake, and can prevent the movement of the steel tower 2 mainly during a strong wind such as a typhoon.

Further, since the legs 5 of the tower 2 are connected to each other by the horizontal connecting member 7, the relative displacement of the legs 5 can be suppressed at the time of an earthquake or when the seismic isolation device is installed. Rigidity can be increased.

In the above-described method of installing the seismic isolation device 10 on the existing steel tower 2, the lower end flange 6 is attached to the lower end of the leg 5.
After installing the temporary support jack 50, the lower part of the lower portion of the lower flange 6 is cut off the leg 5 and the seismic isolation device 10 is inserted therein, and then the temporary support jack 50 is removed. I did it. Thus, the seismic isolation device 10 can be installed on the existing steel tower 2 by easy modification, and as a result, the earthquake resistance of the steel tower 2 can be effectively improved.

[Other Embodiments] Next, another embodiment of the seismic isolation type steel tower 2 according to the present invention will be described. The following shows an example in which each part of the seismic isolation device 10 described above is in another form. Therefore, other configurations, construction methods, and the like not mentioned in the following description are the same as those in the above embodiment.

A slide mechanism 61 shown in FIG. 8 is provided in place of the slide mechanism 13. The slide mechanism 61 includes two sets of slide rails (lower slide members) 62 extending in two mutually orthogonal XY directions.
X and a slide rail (upper slide member) 62Y. These slide rails 62X, 62
Y has a predetermined length in each of the X direction and the Y direction,
Guide grooves 62Xa and 62Ya are provided on the upper surface, and projecting portions 62Xb and 62Y projecting laterally on both sides of the upper end.
b are formed continuously in the respective extending directions. The lower surface of the slide rail 62X in the X direction is integrally fixed to the lower plate member 12. On the bottom surface of the guide groove 62Xa, for example, a flexion absorbing member 64X such as “chloroprene rubber” is laid to absorb flexure such as installation accuracy. A projection 65 is formed below the slide rail 62Y in the Y direction and is located in the guide groove 62Xa of the slide rail 62X. A sliding bearing 66X is provided on the lower surface of the convex portion 65, and the sliding bearing 66X
By sliding on the slide rail 4X, the slide rail 62Y is guided by the guide groove 62Xa of the slide rail 62X and is slidable in the X direction. Further, on both lower sides of the slide rail 62Y, a cross-sectional view L
A character-shaped locking claw (upper displacement restricting member) 67 is provided,
The tip portion is a projecting portion 62Xb of the slide rail 62X.
Is located below or at a predetermined clearance. This restricts the relative movement of the slide rail 62Y upward with respect to the slide rail 62X.

A deflection absorbing member 64Y is laid on the bottom surface of the guide groove 62Ya of the slide rail 62Y in the Y direction. Further, in the guide groove 62Ya, a plate-shaped rail plate 68 is provided on the flexure absorbing member 64Y. A saddle plate 69 integrally fixed to the lower surface of the upper plate member 11 is provided above the slide rail 62Y.
Are arranged. The saddle plate 69 is provided with a sliding bearing 66Y on its lower surface, so that it can slide on the rail plate 68 in the direction in which the slide rail 62Y extends. Further, locking claws (upper displacement restricting members) 69a each having an L-shaped cross section are provided on both sides of the lower surface of the saddle plate 69, and the distal ends of the locking claws 69a are provided below the projecting portions 62Yb of the slide rails 62Y. Contact or at a predetermined clearance. Thus, the upward movement of the saddle plate 69 with respect to the slide rail 62Y is restricted.

With the slide mechanism 61 having such a structure, the upper plate member 11 (on the tower 2 side) and the lower plate member 12 (on the roof side of the building 1) can be relatively displaced in a substantially horizontal direction, and The overhang portions 62Xb, 62Yb and the locking claws 67, 69a restrain the relative displacement in the vertical direction. Therefore, the slide mechanism 6
1 is provided in place of the slide mechanism 13 (see FIG. 3),
Further, similarly to the above, by providing the vibration absorbing / restoring mechanism 14 and the trigger mechanism 15 (see FIG. 2),
The same effect as described above can be obtained.

Next, a laminated rubber (vibration absorption mechanism, slide mechanism) 70 shown in FIG. 9 is provided in place of the slide mechanism 13 and the vibration absorption / restoration mechanism 14. The laminated rubber 70 includes a rigid plate 73 made of a metal material, for example, lead, and a viscoelastic material between an upper plate 71 and a lower plate 72.
For example, an absorption layer 74 made of a rubber-based material or the like is alternately stacked over a plurality of upper and lower layers. Here, the materials of the plywood 73 and the absorbent layer 74 are only examples, and various known laminated rubber devices can be used.

In such a laminated rubber 70, the elasticity of the absorption layer 74 causes the upper plate 71 fixed to the upper plate member 11 via the joint member 75 and the lower plate 72 fixed to the lower plate member 12. Are relatively displaceable in a substantially horizontal direction, and have a function of a slide mechanism and a function of a restoration mechanism. Further, by using a high damping rubber for the laminated rubber or using a rubber in which lead is inserted, the vibration absorbing performance is also exhibited.

Further, the vertical displacement of the laminated rubber 70 is restrained by a locking claw (upper displacement restraining member) 76. The locking claw 76 is provided on the lower plate member 1.
2 and is extended upward, and its tip portion 76a
Is provided on the upper surface of the upper plate 71 of the laminated rubber 70. Thereby, the displacement of the upper plate 71 in the direction away from the lower plate 72 in the upward direction is restrained, and the lifting of the leg 5 of the steel tower 2 can be prevented. The use of such a laminated rubber 70 can also impart seismic isolation performance to the steel tower 2. And by providing the trigger mechanism 15 (see FIG. 2), the same effect as described above can be obtained.

The trigger mechanism 1 shown in FIG.
The trigger mechanism 80 shown here is integrally provided on the outer surface of the upper plate member 11 and extends downward and integrally with the outer surface of the lower plate member 12. A lower bracket 82 is provided and projected, and a shear pin (horizontal displacement restraining member) 83 connecting the upper bracket 81 and the lower bracket 82 is provided. This sheer pin 83
Has a predetermined strength set in advance in the shearing direction, and is connected vertically by being inserted vertically into insertion holes (not shown) formed in the upper bracket 81 and the lower bracket 82, respectively. I do. Thereby, the relative displacement of the upper bracket 81 and the lower bracket 82 in an arbitrary direction in a substantially horizontal plane with one shear pin 83 is improved.
It is designed to exert binding power. As a result, unlike the conventional trigger mechanism 15, there is no need to prepare for each of the X direction and the Y direction.

In such a trigger mechanism 80, when the upper plate member 11 and the lower plate member 12 are about to be displaced in a substantially horizontal direction, the shear pin 83 is broken until the applied shear force reaches a predetermined value. However, in this state, the relative movement between the upper plate member 11 and the lower plate member 12 is restricted, and the seismic isolation device 10 is in a rigid (fixed) state. When the shearing force acting on the shear pin 83 becomes equal to or more than a predetermined value, the shear pin 83 breaks, and as a result, the upper plate member 11 and the lower plate member 12 are substantially moved by the slide mechanism 13 shown in FIG. Relative displacement is enabled in the horizontal direction, and the displacement is suppressed by the vibration absorbing / restoring mechanism 14.

FIG. 11 shows still another embodiment of the trigger mechanism.
Here, an upper bracket 91 integrally attached to the lower surface of the upper plate member 11 and extending downward, a lower bracket 92 integrally provided on the upper surface of the lower plate member 12 and protruding, the upper bracket 91 and the lower bracket Shear pin (horizontal displacement restraining member) connecting to 92
93. Here, the upper bracket 9
The first bracket 1 and the lower bracket 92 are in a state where their tip portions face each other, and through holes 91a and 92a through which the shear pin 93 is inserted are formed therein. The base end 93a of the shear pin 93 is integrally fixed to the lower surface of the upper plate member 12, and is inserted through the insertion holes 91a and 92a. Then, the tip 93 of the shear pin 93
b has a larger diameter than the insertion holes 91a and 92a.

The shear pin 93 is attached to the upper bracket 9
When the first bracket 1 and the lower bracket 92 are to be relatively displaced in an arbitrary direction in a substantially horizontal plane, the shear force generated by the tips of the upper bracket 91 and the lower bracket 92 or the force in the direction in which the shear pin 93 is pulled out is opposed to the above. It exerts a restraining force against displacement. In this state, the seismic isolation device 10 is in a rigid (fixed) state.
Then, when the shearing force or the tensile force acting on the shear pin 93 exceeds a predetermined value, the shear pin 93 breaks, and as a result, the upper plate member 1 shown in FIGS.
1 and the lower plate member 12 can be relatively displaced in a substantially horizontal direction by the slide mechanism 13, and the displacement can be suppressed by the vibration absorbing / restoring mechanism 14. In addition,
Such a shear pin 93 can also function as an upper displacement restricting mechanism that restricts the upper plate member 11 and the lower plate member 12 from being displaced in the direction in which they are vertically separated.

In the above embodiment, the slide mechanisms 13 and 61, the vibration absorbing / restoring mechanism 14, the trigger mechanisms 15, 80 and 90, the laminated rubber 70, and the like can perform their required functions. Alternatively, the configuration may be appropriately changed to another configuration, or the above-described configuration may be used in combination. . Further, as an upward displacement restricting mechanism for restricting the vertical displacement of the seismic isolation device 10, for example, in FIG. 4, the engaging concave portions 26, 26 and the engaging convex portions 27, 27 are provided, but the cross-sectional shape thereof is changed. For example, it may be substantially V-shaped, and the engagement recess 26 may be formed in the slide saddle 23.
X, 23Y side, and the engaging projection 27 is formed on the rail member 22.
It may be formed on the X, 22Y side. FIG.
Alternatively, the seismic isolation device 1 is not limited to the form shown in FIG.
If the vertical displacement of 0 can be constrained, for example,
An upward displacement restraint mechanism may be provided separately from the slide mechanisms 13 and 61.

In the above embodiment, the existing tower 2
The example of newly installing the seismic isolation device 10 for
Of course, the present invention can be applied to a case where a steel tower 2 is newly installed. In this case, after building the building 1, the seismic isolation device 10 may be installed, and the steel tower 2 may be built thereon. In addition, the example in which the steel tower 2 is constructed on the building 1 has been described. However, the present invention is not limited to this, and the steel tower 2 may be installed on a building structure other than the building 1 or on the ground. In addition, the height, weight, structure, and the like of the steel tower 2 itself may be any, and are not limited to the configurations, numerical values, and the like described in the above embodiment.

Other than this, any configuration may be adopted as long as it does not deviate from the gist of the present invention, and it is needless to say that the above-described configurations may be appropriately selectively combined. No.

[0068]

As described above, according to the first aspect,
According to the seismic isolation type tower, a substantially horizontal relative displacement occurs between each leg of the tower and the lower structure due to vibration of a lower structure such as a foundation or a building supporting the tower, for example, during an earthquake,
When the tower period becomes longer, the tower does not follow the movement of the substructure, and vibration of the tower can be suppressed. At the same time, the energy of the relative displacement is absorbed by the vibration absorbing mechanism, and the vibration of the tower can be further reduced. As a result, the seismic performance of the tower can be improved. Although the pulling force of each leg during an earthquake is reduced by reducing the tower vibration, the upper displacement member restrains the upper base member and the lower base member from being separated from each other by a predetermined value or more in the vertical direction by the upper displacement restraining mechanism. Therefore, even in the case of a strong earthquake, each leg does not rise. In addition, this makes it possible to withstand a force in a direction in which each leg is lifted even during a strong typhoon or the like. As a result, it is possible to prevent the tower from being damaged.

According to the seismic isolation type tower according to the second aspect, the upper base member and the lower base member are connected to each other by a slide mechanism so as to be relatively movable in a substantially horizontal direction. While the relative displacement is attenuated by the damper member and the restoring force is applied by a restoring force applying member made of, for example, an elastic material such as a spring, the period of the tower can be adjusted to a longer period side. By restoring to the position, seismic isolation function can be provided.

According to the third aspect of the present invention, the slide mechanism is constituted by a slide bearing, and a damping force for a relative displacement between the upper base member and the lower base member can be given by a frictional force.

According to the seismic isolation type tower according to the fourth aspect, by engaging the engaging projection projecting laterally with the engaging recess, the upper slide member and the lower slide member can be vertically moved. Displacement can be constrained. Thus, it is possible to prevent the legs of the tower from being lifted up due to the vertical displacement of the seismic isolation device.

According to the seismic isolation type steel tower of claim 5, the seismic isolation performance can be imparted to the steel tower by using a so-called laminated rubber or the like as the vibration absorbing mechanism.

According to the seismic isolation type tower according to the sixth aspect, for example, the vertical displacement of the upper slide member and the lower slide member can be restrained by the upper displacement restraint member in the form of a claw. it can.

According to the seismic isolation type tower according to the seventh aspect, in the case of a strong wind or an earthquake having a strength less than the assumed strength, the upper base member side and the lower base member side are connected to each other by the horizontal displacement restraining member, The seismic isolation device becomes rigid and does not operate. When a horizontal displacement restraint member breaks due to a force greater than a predetermined set value due to a strong earthquake or the like,
The restraint in the horizontal direction between the upper base member side and the lower base member side is released, the relative displacement of both sides is allowed, and the vibration of the steel tower can be suppressed by the seismic isolation device. By providing the horizontal displacement restraining member in this way, it is possible to suppress the operation mainly in a strong wind and to provide a seismic isolation device effective only for a strong earthquake.

According to the seismic isolation type tower according to the eighth aspect, the relative displacement between the plurality of legs can be suppressed during an earthquake or the like, and the rigidity of the tower can be increased.

According to the quake-absorbing type tower according to the ninth aspect, by applying the present invention to the tower installed on the building, the vibration of the tower on the building can be effectively suppressed.

According to the method for installing a seismic isolation device on an existing steel tower according to claim 10, a temporary support jack is installed after a flange member is attached to a lower end portion of a leg, and subsequently, a temporary support jack is installed below the flange member. The leg was cut off from the portion, and the seismic isolation device according to any one of claims 1 to 8 was inserted therein, and then the temporary support jack was removed. Thereby, the above-mentioned seismic isolation device can be installed also on the existing steel tower, and as a result, the earthquake resistance of the steel tower can be effectively improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a leg portion of a steel tower to which a method of installing a seismic isolation device on an existing steel tower and an existing steel tower according to the present invention is applied.

FIG. 2 is a side view and a plan sectional view showing a seismic isolation device installed on a leg of the tower.

FIG. 3 is a perspective view showing a slide mechanism constituting the seismic isolation device.

FIG. 4 is a sectional view showing the slide mechanism.

FIG. 5 is a diagram showing a seismic response analysis result of the tower, showing a relative displacement distribution acting on the tower.

FIG. 6 is a diagram showing an absolute acceleration distribution acting on the tower.

FIG. 7 is a process chart showing a method of installing a seismic isolation device on the existing steel tower.

FIG. 8 is a sectional view showing another embodiment of the slide mechanism.

FIG. 9 is a side view showing another form of the vibration absorbing mechanism and the upward displacement restraining mechanism constituting the seismic isolation device.

FIG. 10 is a view showing another embodiment of the horizontal displacement restricting member provided in the seismic isolation device.

FIG. 11 is a view showing still another embodiment of the horizontal displacement restricting member provided in the seismic isolation device.

FIG. 12 is a diagram showing an installation state of a conventional steel tower.

FIG. 13 is a diagram showing an installation state of a steel tower provided with a TMD.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Building (lower structure, building) 2 Steel tower 5 Leg 6 Lower flange (flange member) 7 Horizontal connecting material (leg connecting member) 10 Seismic isolation device 11 Upper plate member (upper base member) 12 Lower plate member (lower base) 13, 61 Slide mechanism 14 Vibration absorbing / restoring mechanism (vibration absorbing mechanism, restoring mechanism) 22X, 62X Rail member (lower sliding member) 22Y, 62Y Rail member (upper sliding member) 26 Engaging recess 27 Engaging convex Reference Signs List 30 damper member 31 spring member (restoring force applying member) 42, 83, 93 shear pin (horizontal displacement restricting member) 50 temporary support jack 67, 69a, 76 locking claw (upper displacement restricting member) 70 laminated rubber (vibration absorbing mechanism, Slide mechanism) 73 Rigid plate 74 Absorbing layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuo Ogi 4--22 Kannon Shinmachi, Nishi-ku, Hiroshima-shi, Hiroshima Mitsubishi Heavy Industries, Ltd. Hiroshima Works (72) Inventor Hideaki Harada 4-chome Kannon-Shimmachi, Nishi-ku, Hiroshima-shi, Hiroshima No. 6-22 Mitsubishi Heavy Industries, Ltd. Hiroshima Research Laboratory F-term (reference) 2E176 AA00 AA11 BB28

Claims (10)

[Claims] 1. A seismic isolation device is interposed between each leg of a tower having a plurality of legs and a lower structure that supports the tower, respectively. An upper base member fixed to the lower structure member; a lower base member fixed to the lower structure side; provided between the upper base member side and the lower base member side; On the other hand,
A vibration absorbing mechanism for absorbing vibration energy, a restoring mechanism for providing a restoring force to lengthen the period of the tower, and an upper displacement constraint for restraining the upper base member and the lower base member from separating from each other by a predetermined value or more in a vertical direction. A seismic isolation tower characterized by having a mechanism. 2. A sliding mechanism, wherein the vibration absorbing mechanism and the restoring mechanism connect the upper base member and the lower base member so as to be relatively movable in a substantially horizontal direction, and between the upper base member and the lower base member. A viscous or hysteretic damper member that is provided and exerts a damping force on the relative displacement in both substantially horizontal directions, and is provided between the upper base member and the lower base member, and The seismic isolation type tower according to claim 1, further comprising a restoring force applying member that applies a restoring force and lengthens a period of the tower. 3. The slide mechanism according to claim 2, wherein the slide mechanism is constituted by a slide bearing, and a damping force for a relative displacement between the upper base member and the lower base member is applied by a frictional force. Seismic isolation tower. 4. The seismic isolation type tower according to claim 2, wherein
As the upper displacement restricting mechanism, the slide mechanism is connected to an upper slide member on the upper base member side and a lower slide member on the lower base member side slidably movable in a substantially horizontal direction with respect to the upper slide member. And one of the upper slide member and the lower slide member is provided with an engagement protrusion protruding laterally, and the other engages with the engagement protrusion. A seismic isolation type tower with a joint recess. 5. The apparatus according to claim 1, wherein the vibration absorbing mechanism and the restoring mechanism comprise a rigid plate made of a metal material and an absorbing layer made of a viscoelastic material between the upper base member and the lower base member. The seismic isolation type tower according to claim 1, wherein the tower is configured to be alternately stacked. 6. An upper displacement restricting member is provided on the lower base member side as the upper displacement restricting mechanism, the upper displacement restricting member extending toward the upper base member side and restricting upward displacement of the upper base member. The seismic isolation tower according to any one of claims 1 to 5, wherein: 7. The upper base member side and the lower base member side are connected to each other by a horizontal displacement restraining member that does not break until a predetermined set value of a substantially horizontal force is applied, and the upper base member side and the lower base member side are relatively opposed to each other. The seismic isolation tower according to any one of claims 1 to 6, wherein the displacement is restricted. 8. The seismic isolation tower according to claim 1, further comprising a leg connecting member for connecting the plurality of legs to each other. 9. The tower according to claim 1, wherein the tower is installed on a building as the lower structure.
The seismic isolation tower according to any one of items 1 to 8. 10. A method for installing a seismic isolation device on each of a plurality of legs of an existing tower, comprising: attaching a flange member projecting outward to a lower end of the legs; A temporary support jack is installed between the supporting lower structure and the flange member.Subsequently, a portion below the flange member is cut off at the leg portion, and between the flange member and the lower structure,
10. A method for installing a seismic isolation device on an existing steel tower, comprising inserting the seismic isolation device according to any one of claims 1 to 9, and then removing the temporary support jack.