JP2710733B2 - Damping structure stack - Google Patents

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 having a function of damping vibration in the stack itself.

[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 cylinder body is secured by being connected to the cylinder body via a floor slab for landing, for example, when attached to a boiling water type nuclear power plant,
When building on a high-rigidity concrete structure, the response acceleration during earthquakes of the relatively low-rigidity stack is very large, and vibration increases. A means for reducing vibration is needed again.

[0003] The present invention has been made in view of the problem of vibration during an earthquake which is encountered when the stack is built on a high rigidity substructure, and attempts to propose a stack having a structure for damping vibration by itself. Is what you do.

[0004]

According to the present invention, one side of a floor slab for connecting a tubular body and a steel tower is separated from the tubular body or the steel tower, and the floor slab and the tubular body on the separated side are separated from each other or the floor. An elasto-plastic damper is installed between the slab and the tower to attenuate vibrations when the horizontal displacement between them is relatively large, and the elasto-plastic damper uses the difference in vibration characteristics between the tubular body and the tower to exhibit the damping ability. Damping the vibration of the stack and securing the safety of the stack on a highly rigid structure such as a concrete structure during an earthquake.

The floor slab is connected to one of the tubular body and the steel tower and separated from the other. The tubular body or the floor slab separated from the steel tower, that is, the floor slab on which the elasto-plastic damper is installed is mounted on the tubular body. Or, it is supported by a tubular body or a steel tower so as to be movable relative to the steel tower in the horizontal direction. The floor slab is supported by both the tower or tube connected to it and the tube or tube separated from it.

The elasto-plastic damper is in the form of a rotating body whose cross-sectional area increases from both ends in the axial direction to the center, and is installed between the floor slab and the cylinder, or between the floor slab and the steel tower, with the shaft facing vertically. Is done. Both ends in the axial direction are rotatably connected to a tubular body or a steel tower, and a central portion in the axial direction is fixed to a floor slab. Due to this mounting state, the elasto-plastic damper functions as a free-standing cantilever beam at any relative horizontal displacement between the tubular body and the steel tower.

[0007] Since the elasto-plastic damper is installed by using a floor slab connecting the tubular body and the tower, it does not require a scale as large as being directly installed between the tubular body and the tower, and the weight of the entire stack is reduced. The effect on weight is small. In addition, since it is accommodated in the height direction with respect to the cylindrical body and the steel tower, there is no need to take up space on the floor, within the floor slab, and the flat area of the floor slab is not reduced.

The elasto-plastic damper absorbs both vibration energy at the time of relative displacement between the floor slab and the tower or between the floor slab and the cylinder based on the difference between the natural frequencies and the vibration modes of the tube body and the tower, and the stacking of the stack. Damping vibration.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A stack 1 according to the present invention has a structure as shown in FIG.
Surrounds the cylindrical body 2 and its surroundings, and is spaced apart in the height direction,
It consists of a truss-structured tower 3 connected to the barrel 2 via a landing deck 5 for each floor, and is installed between the deck 5 and the barrel 2 or between the deck 5 and the tower 3. The vibration during an earthquake is attenuated by an elastic-plastic damper (hereinafter referred to as a damper) 4.

The floor slabs 5 are installed on each floor of the stack 1, and the dampers 4 are installed on the required floor slabs 5 having a high damping effect as the whole stack 1. In terms of the damping efficiency, it is sufficient to install the damper 4 at least at the top position and the middle floor position of the stack 1 as described later.

FIG. 2 is a cross-sectional view of FIG. 1 at the floor where the damper 4 is installed. As shown here, the floor slab 5 projects from the outer periphery of the cylindrical body 2. the tubular body 2 by being connected, is connected to the main pillar 3 _1, 3 horizontal member 3 which is installed between _{1 2} and horizontal members 3 _2, 3 horizontal braces 3 ₃ which is installed between _two towers 3 Thereby, it is respectively supported by the steel tower 3. The floor slab 5 of the floor where the damper 4 is installed is connected to one of the tubular body 2 and the steel tower 3, and is separated from the other side by installing the damper 4 on the other side, and is relatively movable in the horizontal direction. Supported by

FIG. 2 shows a case where the floor slab 5 is connected to the steel tower 3 and separated from the tubular body 2. In this case, the floor slab 5 is shown in FIG. 3 which is a sectional view of the tubular body 2 side in FIG. Thus, the cylinder body 2 is separated by the damper 4 so as to be relatively displaceable.

As shown in FIG. 3, the damper 4 includes a supporting member 6 integrated with the edge of the floor slab 5 on the side of the cylinder 2, and
It is installed so as to straddle between the projecting members 7 which are projected and fixed to the side. When the floor slab 5 is connected to the tubular body 2 and separated from the steel tower 3, the arrangement of the floor slab 5 with the steel tower 3 is the same as in FIG. In that case, the damper 4 is disposed between the floor slab 5 and pylon 3, is connected to a suitable member such as the horizontal member 3 ₂ or horizontal braces 3 ₃ or projecting member 7,,, slab 5 of the street, It is supported by the tubular body 2 by being connected to the overhang member 7 and the support member 8.

The damper 4 is in the form of a rotating body whose cross-sectional area increases from both ends in the axial direction to the central portion. As shown in FIG. 3, the damper 4 is installed so that the shaft is oriented vertically, and both ends in the axial direction are cylindrical bodies. 2, and is rotatably connected to the steel tower 3, and the central portion in the axial direction is fixed to the floor slab 5. In the case of FIG. 3 in which the floor slab 5 is separated from the cylindrical body 2, both end portions of the spherical shape are connected to the overhanging member 7 so as to allow rotational deformation accompanying the relative movement between the cylindrical body 2 and the steel tower 3, and the central portion is formed. Are fixed to the support member 6.

The portion of the floor slab 5 other than the installation location of the damper 4 on the side where the damper 4 is installed is attached to the cylindrical body 2 or the steel tower 3 as shown in FIG. The tube body 2 or the tower 3 can be moved relative to the horizontal direction.
Supported by In the embodiment in which the damper 4 is installed on the side of the tubular body 2, the floor slab 5 is connected to the supporting members 8, 8 fixed to the tubular body 2 by being sandwiched between the supporting members 8, 8, and both sides of the floor slab 5 and the supporting members 8, 8 By interposing the low friction materials 9, 9 between them, relative movement without resistance is generated between the floor slab 5 and the tubular body 2, and both are substantially separated. Also when the damper 4 is connected to the tower 3 side, the floor slab 5 and the tower 3 are separated in the same manner as in FIG.

Here, the damping effect of the damper 4 of the stack 1 of the present invention will be described. The stack 1 is provided with two bending / shearing rods corresponding to the cylindrical body 2 and the steel tower 3 and a dash corresponding to the damper 4 inserted between the two. It is confirmed based on the analysis model shown in FIG. 5 replaced with a pot (viscous damper). In the figure, the numbers encircled by o represent the mass point numbers, and the numbers not enclosed represent the member (layer) numbers.

In the basic model, dashpots are installed at the top, middle, and lower portions of the stack 1. However, the deformation of the damper 4 installed at the lowermost portion is small, and the dashpot is applied to the primary vibration mode of the entire stack 1. Since the influence is small, the seismic response analysis was performed for the following three cases including the case where the lowermost damper 4 was not present. (1) Basic (without damper): When the tubular body and the tower are connected by rigid springs at the top, middle and lower positions.

(2) Three dampers: When the rigid spring of (1) is replaced with a viscous damper. (3) Two dampers: When the lowermost damper in (2) is removed.

The input wave is a floor response waveform at the base level of the stack 1 obtained by a generally used design seismic motion, and its acceleration response spectrum is shown in FIG. The figure also shows the natural period of the cylindrical body 2 and the steel tower 3 alone, in addition to the natural period of the entire stack 1.

Since the first to third order vibration modes of the stack 1 are highly stimulating, if the optimal value of the damping coefficient of the stack 1 is set from the relationship between the damping coefficient up to the third order and the damping coefficient of the dashpot. As shown in FIG. 7, the attenuation constant up to the third order varies depending on the value of the attenuation coefficient. However, when the second-order and third-order attenuation constants are relatively large immediately before the first-order attenuation constant decreases. Damping coefficient value (C = 0.2tonf / kine)
Was adopted in the seismic response analysis model.

The response maximum acceleration for each of the tower 3 and the cylinder 2 obtained from the seismic response analysis for the above three cases,
Fig. 8 to Fig. 8 show the distribution of the maximum response displacement and maximum response shear force.
See Figure 13. In the figure, ●-● indicates the case of (1) above, and △-△ indicates
The case of (2) shows the case where ○-○ is (3).

From these figures, there is almost no difference between the response values in the cases (2) and (3). In each case, the acceleration and displacement at the top of the tower 3 are about 60% as compared with the case (1). It can be seen that the base shear is reduced by about 55%, the acceleration at the top of the cylinder body 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 the examination in the case where the damper 4 is a viscous damper. Similar results are obtained in the case where the damper 4 is an elasto-plastic damper. From these results, the damper 4 is connected to the vicinity of the top of the stack 1 and the intermediate position. It can be seen that the vibration can be efficiently attenuated only by installing the stack 1, and at the same time, the stack 1 can be reasonably designed.

[0024]

According to the present invention, an elasto-plastic damper for separating one side of a floor slab connecting a tubular body and a steel tower from the tubular body or the steel tower and attenuating vibration between the separated tubular body and the steel tower upon relative displacement between the two. In order to make the elasto-plastic damper exhibit the damping ability by installing and using the difference in the vibration properties of the tubular body and the tower,
Both vibrations during an earthquake are damped, and the safety of the stack on a concrete structure having high rigidity can be ensured.

In particular, since the elasto-plastic damper is installed by using a floor slab connecting the tubular body and the steel tower, the elasto-plastic damper does not need to be as large as the case where it is directly installed between the tubular body and the steel tower. , Has a small effect on the weight of the entire stack. Further, since the elasto-plastic damper is accommodated in the height direction with respect to the tubular body and the steel tower, it does not take up space on the floor and in the floor slab, and does not reduce the plane area of the floor slab.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view of FIG. 1 at an installation floor of an elastic-plastic damper.

FIG. 3 is a sectional view taken along line xx of FIG. 2;

FIG. 4 is a sectional view taken along line yy of FIG. 2;

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 an attenuation coefficient and an attenuation constant.

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

FIG. 9 is a graph showing a response acceleration of a tubular body.

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

FIG. 11 is a graph showing a response displacement of a tubular body.

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

FIG. 13 is a graph showing a response shear force of a tubular body.

[Explanation of symbols]

1 ... stack, 2 ... tubular body, 3 ... steel tower, 3 ₁ ... main pillar, 3 ₂ ... horizontal material, 3 ₃ ... horizontal brace, 4 ... elastic-plastic damper, 5 ... floor slab, 6 support member, 7 overhang member, 8 support member, 9 low friction material.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Nobuyuki Miyagawa 1-2-7 Moto-Akasaka, Minato-ku, Tokyo Kashima Construction Co., Ltd. (72) Hideki Morishita 2-2-2 Kanda Jimbocho, Chiyoda-ku, Tokyo No. 30 Within the Tokyo Electric Power Company Nuclear Research Laboratory (72) Inventor Kiyoshi Nakamura 2-3-2 Kanda Jimbocho, Chiyoda-ku, Tokyo Tokyo Electric Power Company Nuclear Research Laboratory (56) Reference JP-A-2-101267 (JP, A JP-A-4-119231 (JP, A) JP-A 62-199468 (JP, U) JP-B 50-22730 (JP, B2) JP-B 55-24546 (JP, B2)

Claims (1)

(57) [Claims] 1. A stack comprising a tubular body and a truss-structured tower surrounding the periphery thereof and connected to the tubular body via a floor slab installed at an interval in a height direction, The slab is connected to one of the tubular body and the tower and separated from the other, and the relative horizontal displacement between the separated floor slab and the tubular body or between the deck and the tower, An elasto-plastic damper is sometimes installed to attenuate both vibrations, and the floor slab is supported by the tubular body or the tower so that it can move relative to the tubular body with the elasto-plastic damper or the tower horizontally. The elasto-plastic damper has the shape of a rotating body whose cross-sectional area increases from both ends in the axial direction to the center. The shaft faces in the vertical direction, and both ends in the axial direction are rotatably connected to a cylinder or a steel tower. , A damping structure stack whose axial center is fixed to the floor slab.