JPH09310530A - Control structure for long frequency - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the transmission of the acceleration and the horizontal displacement to the upper layer in an earthquake, by forming the horizontal rigidity of the lower layer as a soft structure and installing a vibration-control device and giving a control force proportional to the product of the rigidity of the lower layer and the displacement at the earthquake to the structure by the vibration-control device. SOLUTION: An actuator 2 is installed at the head of a brace of the first layer of a structure 1. In this case, the horizontal deformation brought in the first layer at an earthquake and the control force proportional to the rigidity act in the increasing direction of the deformation, in the actuator 2. Accordingly, the horizontal rigidity of the first layer is decreased as much as the deformation and the control force. The vibrational period becomes longer than the proper period of the structure 1 and the earthquake acceleration input to the upper layer is reduced. Since the rigidity of the layer on which an control force acts is made to form a soft structure, the vibration-control device necessary for energy is limited to only one layer. In this way, the supply of energy and keeping of the installation space can be easily executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a structure in which the horizontal rigidity of a low layer of a structure is a flexible structure, an actuator is provided in the layer, and a control force proportional to the product of the deformation and the rigidity of the layer during an earthquake is applied in the direction of deformation. It causes the rigidity of the structure to decrease,
The present invention relates to a structure in which the acceleration of the immediately upper layer during an earthquake is reduced and the seismic input response to the upper layer is reduced by lengthening the vibration period of the structure.

[0002]

2. Description of the Related Art In the event of an earthquake, the acceleration and horizontal displacement to the upper layers are compared to the case where a vibration control device is uniformly attached to columns and beam frames of each layer of a structure. An active vibration control structure that reduces transmission has already been applied for in Japanese Patent Application No. 8-55853.

According to Japanese Patent Application No. 8-55853, the horizontal rigidity of the lower layer of the structure (for example, the first layer) is flexible, and the vibration control devices (for example, actuators) are provided on the columns and beam frames, and the upper layers A vibration control device (for example, variable damping device) is arranged in a pillar or beam frame, and the vibration amount of the upper layer (for example, the second layer) of the lower layer is controlled by the vibration control device for the lower layer (for example, the first layer).
It is an active vibration control structure that suppresses the horizontal acceleration and the acceleration that is returned to the upper layers.

The present invention is derived from the invention of Japanese Patent Application No. 8-55853, in which the horizontal rigidity of the lower layer of the structure is a flexible structure, and the seismic control device is provided on the pillar or beam frame to prevent horizontal movement during an earthquake. A control force proportional to the deformation and rigidity is applied to the displacement direction of the structure,
The problem is to reduce the seismic input response of the upper layer by making the structure vibrate longer than the period.

[0005]

[Means for Solving the Problems] A structure with a long-period control, in which the horizontal rigidity of the lower layer of the structure is a flexible structure, and a damping device is provided in the lower layer, and the product of the deformation and the rigidity of the layer is obtained during an earthquake. The purpose is to be a long-period control structure characterized in that a proportional control force is applied in a direction in which deformation is increased to reduce horizontal rigidity and the period is made longer than the vibration period of the structure. To do.

The low layer is, for example, the first layer, and an actuator or a variable damping device can be used as the vibration control device.

As a means for making the horizontal rigidity of the first layer a flexible structure, the bending rigidity of the columns of the first layer is reduced within a range in which the vertical force can be supported. For example, in the case of a box column, the bending rigidity can be reduced without reducing the vertical supporting force as a solid cross section. However, a supporting device is installed to avoid the risk of buckling.

The control force F is expressed by F = -αK × X (t). Here, α is a constant represented by 0 <α ≦ 1, K is the horizontal rigidity of the first layer, X (t) is the interlayer deformation t occurring in the layer at the time of an earthquake, and t is the elapsed time.

Here, the larger the value of α, the greater the control effect.

Next, an example of analysis when an earthquake of El Centro 100 Gal acts on a 9-story steel structure will be shown. FIG.
[Fig. 4] is a graph comparing input accelerations of respective layers.

FIG. 3 is a graph comparing the interlayer deformation of each layer.

As can be seen from FIG. 2, when a control force is applied, the acceleration input on the upper floors is small and α is large,
The response acceleration is small.

As can be seen from FIG. 3, the horizontal deformation of the first layer is larger when a control force is applied, but in the upper floors, the interlayer displacement is generally smaller as α is larger.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention.

The actuator 2 is installed on the head 3 of the brace of the first layer of the structure 1. The horizontal deformation of the first layer at the time of the earthquake and the control force proportional to the rigidity are applied to the actuator in the direction of increasing the deformation, and the horizontal rigidity of the first layer is reduced accordingly. Therefore, the vibration period becomes longer than the natural period of the structure when no control force is applied, and the seismic acceleration input to the upper layer can be reduced. Needless to say, a variable damping device may be used instead of the actuator.

[0017]

The lower layer of the structure (for example, the first layer) has a horizontal rigidity that is softer than that of the other layers, and a vibration control device (actuator or the like) is installed in the layer, and the vibration control device lowers the rigidity of the lower layer. By applying a control force proportional to the product of the displacement at the time of the earthquake and the displacement at the time of the earthquake, the acceleration of the second layer is reduced during the earthquake and the transmission of the acceleration to the upper layer is reduced.

Further, since the layer for exerting the control force has a flexible structure, the energy required for control can be suppressed to a small level, and the energy control device is restricted to only one layer. It is possible to easily supply the space and secure the installation space.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram comparing input accelerations of respective layers in a graph.

FIG. 3 is a graph comparing the interlayer deformation of each layer.

[Explanation of symbols]

1 ... High-rise structure, 2 ... Actuator, 3 ... Brace head

Claims (1)

[Claims] 1. A long-period control structure, wherein the horizontal rigidity of the lower layer of the structure is a flexible structure, a damping device is provided in the lower layer, and control is proportional to the product of deformation and rigidity of the layer during an earthquake. A long-period control structure, wherein a force is applied in a direction in which deformation is increased to reduce horizontal rigidity, and the period is made longer than the vibration period of the structure.