JPH0666048A - Damping structure stack - Google Patents

Abstract

PURPOSE:To secure the seismic safety of a stack in case it is built upon the substructure having a high rigidity. CONSTITUTION:A damping stack is composed of a barrel 2 and a truss structure steel tower 3 coupled with the barrel 2 through a floor plate 5 located a certain distance apart in the height direction. The floor plate 5 is connected with either of the barrel 2 while steel tower 3 and separated from the other, and a damper 4 is installed between the floor plate 5 on the separated side and the steel tower 3 or the barrel 2 so as to damp the vibrations of the two parties when they are in relative displacement. Thereby the damper 4 exerts the damping ability due to difference in the vibratory traits of the barrel 2 and steel tower 3, damps the vibrations of the two parties, and secures the seismic safety on the structure presenting a high rigidity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping structure stack in which the stack itself has a function of damping vibration.

[0002]

A stack installed in a thermal power plant, a nuclear power plant or the like is composed of a cylindrical body of a main body and a steel tower surrounding the body, and the steel tower is installed at a stop floor position of an elevator. The structural safety of the barrel is secured by being connected to the barrel through the floor plate for landings, but for example, when attached to a boiling water nuclear power plant,
When built on a high-rigidity concrete structure, the response acceleration of a relatively low-rigidity stack is extremely large during an earthquake, and the vibration increases. A means for reducing vibration is needed again.

The present invention has been made by paying attention to the problem of vibration during an earthquake, which is encountered when the stack is constructed on a highly rigid substructure. An attempt is made to propose a stack having a structure for damping the vibration by itself. To do.

[0004]

According to the present invention, one side of a floor plate for connecting a tubular body and a steel tower is separated from the tubular body or the steel tower, and vibration is generated between the tubular body and the steel tower, which are separated from each other, when the two are relatively displaced. A damper is installed to dampen, and the difference between the vibration characteristics of the cylinder and the steel tower is utilized to allow the damper to exert its damping capacity to dampen both vibrations, causing a stack earthquake on a highly rigid structure such as a concrete structure. Secure the safety of time.

The floorboards are installed between the barrel and the steel tower at intervals in the height direction of the stack, and one side of the floorboard is connected to either one of the barrel and the steel tower, and at the same time, it is separated from the other and the separated side. A damper is installed between the floorboard and the steel tower, or between the floorboard and the barrel.

The damper absorbs the vibration energy of both the floor plate and the steel tower or the relative displacement between the floor plate and the cylinder based on the difference between the natural frequencies and the vibration modes of the cylinder and the steel tower, or attenuates the vibration of the stack. .

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing an embodiment.

As shown in FIG. 1, the stack 1 of the present invention includes a cylinder body 2 and a cylinder surrounding the circumference of the cylinder body 2 with a landing floor plate 5 installed at each floor at intervals in the height direction. It is composed of a truss structure steel tower 3 connected to the body 2, and a damper 4 installed between the cylinder body 2 at a certain floor plate 5 position and the steel tower 3 attenuates vibration during an earthquake.

The floor board 5 is installed on each floor of the stack 1, but the damper 4 is installed on the floor board 5 of a necessary floor where the damping effect of the entire stack 1 is high. In terms of damping efficiency, it is sufficient to install the damper 4 at least at the top position and the intermediate floor position of the stack 1 as described later.

FIG. 2 shows a cross section of FIG. 1 on the floor where the damper 4 is installed. The floor plate 5 is connected to an overhanging member 7 and a supporting member 8 which will be described later and overhang from the outer circumference of the tubular body 2. the cylindrical body 2 by the horizontal braces 3 ₃ which is laid in the horizontal member 3 ₂ and horizontal members 3 _2, 3 between ₂ to be installed between the main pillar 3 _1, 3 ₁ of tower 3
The steel towers 3 are respectively supported by being connected to.
The floor plate 5 on the floor on which the damper 4 is installed is connected to either one of the barrel 2 and the steel tower 3, and is separated from the side by installing the damper 4 on the other side.

In the embodiment shown in FIG. 2, the floor plate 5 is connected to the steel tower 3 and separated from the barrel 2. In this case, the floor plate 5 is a sectional view on the barrel 2 side in FIG. As shown in, the damper 4 separates the cylinder body 2 so that the cylinder body 2 can be displaced relative thereto. As shown in FIG. 3, the damper 4 is installed so as to straddle between a support member 6 that is integrated with the edge of the floor plate 5 on the side of the barrel 2 and an overhanging member 7 that extends from the barrel 2 to the side of the floor plate 5 and is fixed. It Even when the floor plate 5 is connected to the tubular body 2 and separated from the steel tower 3, the engagement of the floor plate 5 with the steel tower 3 is the same as in FIG. 3, and in that case, the damper 4 includes the floor plate 5 and the steel tower 3.
It is installed between and is connected to a suitable member such as the horizontal member 3 ₂ or the horizontal brace 3 ₃ or the overhang member 7. In this case, the floor plate 5 is supported by the barrel 2 by being connected to the overhanging member 7 and the supporting member 8 as described above.

FIG. 3 shows an example of using an elastic-plastic elasto-plastic damper of the type in which the damper 4 bears a horizontal force during relative movement between the barrel 2 and the tower 3 and yields by a bending moment. However, since the elasto-plastic damper of the embodiment functions with respect to the external force at the time of relative movement in the direction orthogonal to the axis, the axis is installed in the direction perpendicular to the surface of the floor plate 5. Further, since the damper 4 shown in the figure has a cantilevered shape for bearing an external force, the base side having a large cross section is fixed to the support member 6, and the spherical head side is the extension member 7 between the barrel 2 and the steel tower 3. It is connected in a state in which rotational deformation due to relative movement is allowed.

The damper 4 used in the present invention only needs to generate a damping force when the cylindrical body 2 and the steel tower 3 move relative to each other, that is, relative movement in a horizontal plane. Not limited to the third embodiment, a viscous damper, a viscoelastic damper, or the like may be used instead. The viscous damper and the viscoelastic damper are also installed on the side of the barrel 2 so as to straddle the floor plate 5 by utilizing the projecting member 7 and the supporting member 8 which are provided on the outer periphery of the viscous damper.

The portion of the floor plate 5 other than the installation location of the damper 4 on the side where the damper 4 is installed is shown in FIG. 4 which is a sectional view taken along the line yy of FIG. It is supported by this in a relatively movable state. In the embodiment in which the damper 4 is installed on the cylinder body 2 side, the floor plate 5 is sandwiched between the support members 8 fixed to the cylinder body 2 to be connected thereto.
By interposing the low friction materials 9 and 9 between both sides of the floor plate 5 and the supporting members 8 and 8, relative movement without resistance between the floor plate 5 and the barrel 2 is generated, and the two are substantially separated. Even when the damper 4 is connected to the steel tower 3 side, the floor plate 5 and the steel tower 3 are separated in the same manner as in FIG.

Here, the damping effect of the damper 4 of the stack 1 according to the present invention will be described. The stack 1 is inserted between the two bending shear rods corresponding to the barrel 2 and the tower 3, and the dash corresponding to the damper 4 is inserted between the two. Confirm based on the analytical model shown in FIG. 5 replaced with a pot (viscous damper). In the figure, the numbers circled are mass point numbers, and the numbers not enclosed are member (layer) numbers.

In the basic model, the dashpots are installed at the top, middle and lower parts of the stack 1, but the damper 4 installed at the bottom has a small deformation and gives the primary vibration mode of the entire stack 1. Since the effect is small, seismic response analysis was performed for the following three cases including the case where the damper 4 at the bottom was absent. (1) Basic (without damper): When the barrel and the steel tower are connected by a rigid spring at the top, middle and lower positions. (2) Three dampers: When the rigid spring in (1) is replaced with a viscous damper. (3) 2 dampers: In the case of (2), the bottom damper is removed.

The input wave is a floor response waveform at the base level of the stack 1 obtained by a commonly used design earthquake motion, and its acceleration response spectrum is shown in FIG. In addition to the natural period of the stack 1 as a whole, the same figure also shows the natural period of the barrel 2 and the tower 3 alone.

In the stack 1, since the stimuli of the first to third order vibration modes are large, if the optimum value of the damping coefficient of the stack 1 is set from the relationship between the damping coefficient of the third order and the damping coefficient of the dashpot. Often, as shown in FIG. 7, the damping constant up to the third order varies depending on the value of the damping coefficient. However, when the damping constants of the second and third orders are relatively large immediately before the value of the first order damping constant decreases. Attenuation coefficient value (C = 0.2 tonf / kine)
Was adopted in the seismic response analysis model.

The maximum response acceleration for each of the tower 3 and barrel 2 obtained from the seismic response analysis for the above three cases,
Distribution of maximum response displacement and maximum response shear force
Shown in 13. In the figure, ●-● is the case of (1) above, and △-△ is
The case of (2) shows the case of ○-○ is (3).

From these figures, there is almost no difference between the response values in the cases of (2) and (3). In both cases, the acceleration and displacement at the top of the steel tower 3 is about 60% compared to the case of (1). It can be seen that the base shear is reduced by about 55%, the acceleration at the top of the barrel 2 is reduced by 75%, the displacement is reduced by 60%, and the base shear is reduced by 50%.

The above is the result of examination when the damper 4 is a viscous damper, but the same result is obtained when the damper 4 is an elasto-plastic damper. From these results, the damper 4 is positioned at the top of the stack 1 and at the intermediate position. It can be understood that the vibration can be efficiently damped only by installing it in a place, and at the same time, the rational design of the stack 1 becomes possible.

[0022]

The present invention is as described above, and one side of the floor plate that connects the tubular body and the steel tower is separated from the tubular body or the steel tower, and at the time of relative displacement between the tubular body and the steel tower separated from each other. Since a damper that damps vibration is installed and the damping capacity of the damper is exerted by utilizing the difference in vibration characteristics between the barrel and the steel tower, it is a highly rigid concrete structure that dampens both vibrations during an earthquake. The safety of the stack above can be ensured.

[Brief description of drawings]

FIG. 1 is an elevational view showing a stack of the present invention.

FIG. 2 is a sectional view of FIG. 1 on a floor where a damper is installed.

FIG. 3 is a sectional view taken along line xx of FIG.

FIG. 4 is a sectional view taken along line yy of FIG.

FIG. 5 is a model diagram for seismic response analysis of a stack.

FIG. 6 is an acceleration response spectrum diagram of a stack input wave.

FIG. 7 is a graph showing a relationship between a damping coefficient and a damping constant.

FIG. 8 is a graph showing response acceleration of a steel tower.

FIG. 9 is a graph showing the response acceleration of the barrel.

FIG. 10 is a graph showing a response displacement of a steel tower.

FIG. 11 is a graph showing a response displacement of a barrel.

FIG. 12 is a graph showing a response shear force of a steel tower.

FIG. 13 is a graph showing the response shear force of the barrel.

[Explanation of symbols]

1 …… Stack, 2 …… Cylinder, 3 …… Steel tower, 3 ₁ …… Main pillar, 3 ₂ …… Horizontal material, 3 ₃ …… Horizontal brace, 4 …… Damper, 5 …… Floor plate, 6 …… Support member, 7 ... Overhang member, 8
…… Supporting member, 9 …… Low friction material.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobuyuki Miyagawa 1-2-7 Moto-Akasaka, Minato-ku, Tokyo Kashima Construction Co., Ltd. No. 30 TEPCO Atomic Energy Research Institute (72) Inventor Kiyoshi Nakamura 2-30 No. 30 Kanda Jinbocho, Chiyoda-ku, Tokyo TEPCO Atomic Energy Research Institute

Claims (1)

[Claims] 1. A stack comprising a tubular body and a truss-structured steel tower that is connected to the tubular body through floor plates that surround the periphery of the tubular body and are installed at intervals in the height direction. Is connected to either one of the barrel and the steel tower and is separated from the other, and damps the vibration of both sides between the floor plate and the steel tower on the separated side or between the barrel and the relative displacement between them. Damping structure stack with a damper installed.