JPH11230252A - Earthquak mitigating method for structure and variable damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the vibrational response of a structure more effectively at an earthquake or like by switching the damping coefficient of a variable damper so that the vibration of an additional aseismatic element such as a brace is employed or increased for higher damping force. SOLUTION: On receiving information, or oil pressures P1 and P2 in hydraulic chambers 5a and 5b defined in left and right and a relative displacement δ1 of a piston 3 to a cylinder 2 inside a variable damper, a controller 8 feeds a control command to a flow control valve 7 depending on these data. The variable damper is disposed between a framework and an additional aseismatic element such as a brace to use the relative vibration of the additional aseismatic element with respect to the framework. The damping coefficient C of the variable damper is controlled such that its damping force is increased while the vibration of the additional aseismatic element is increased. In parallel to the flow control valve 7 of the variable damper, a relief valve 10 is arranged to prevent the additional aseismatic element from suffering an excessive force when the damping coefficient is changed over from the minimum value Cmin to the maximum value Cmax .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure damping method for reducing the response of a structure during an earthquake or the like and a variable damping device used in the method.

[0002]

2. Description of the Related Art A vibration damping system in which a variable damping device (see, for example, Japanese Patent Publication No. 7-45781) for changing a damping device is installed in a beam-column structure of a structure through an additional seismic element such as a brace is known. is there.

[0003] Various vibration control methods using such a vibration control system have been considered. For example, Tokiko 7-47896
And Japanese Patent No. 2513297.

[0004]

In these examples, a variable damping device 1 is installed between a column 11, a beam 12 and a brace 13 as an additional seismic element which constitute a frame shown in FIG. ) And a vibration model (M is the mass of the beam-column structure, K
₁ is the rigidity of the beam-column structure, m is the mass of the added seismic element, K ₂
Is the rigidity of the additional seismic element, C is the damping coefficient of the variable damper,
δ ₁ is the displacement between the cylinder and rod of the variable damper, δ ₂
Is the displacement of the additional seismic resistance element, and δ is the layer displacement of the beam-column structure) by controlling the damping coefficient C of the variable damping device 1 when a vibration external force such as an earthquake is input to the structure. Although the damping force is applied to the frame to reduce the response of the beam-to-column structure, and ultimately the entire structure, the response is mainly controlled based on the response of the beam-to-column structure. It cannot exceed the range of structural restrictions shown.

The present invention increases the damping force by switching the damping coefficient of a variable damping device so as to utilize and increase the vibration of an additional seismic element such as a brace during an earthquake or the like, thereby increasing the damping force and reducing the response of the structure more effectively. It is an object of the present invention to provide a vibration control method capable of performing the vibration control and a variable damping device used in the vibration control method.

[0006]

According to a first aspect of the present invention, an additional seismic element is provided in a column-beam frame of a structure, and a variable damping device is installed between the column-beam frame and the additional seismic element. By controlling the damping coefficient of the variable damping device based on the response of the beam-column structure when an external force such as an earthquake is input to the object,
In a vibration damping method for a structure in which a damping force is applied to a beam-column structure to reduce a response of the structure, a relative vibration of the additional earthquake-resistant element with respect to the beam-column frame is used, and the vibration of the additional earthquake-resistant element is reduced. The damping coefficient of the variable damping device is controlled so as to increase the damping force of the variable damping device while increasing the damping force.

[0007] In other words, a variable damping device is installed between an additional seismic element such as a stud and a column having a low rigidity, and the vibration of the additional seismic element is used in the control thereof. The purpose of this invention is to reduce the response of a structure by storing and consuming more energy of the external force due to vibration or the like in the additional seismic element.

According to a second aspect of the present invention, in the vibration damping method according to the first aspect, the structure of the oil-sealed variable damping device is limited, and a cylinder connected to one of a beam-column frame and an additional seismic element is provided. Reciprocating within, a piston having a rod connected to the other of the beam-column frame and the additional seismic element, a hydraulic chamber formed on both sides of the piston, and a flow path connecting the two hydraulic chambers, In this case, a variable damping device having a flow control valve provided in the flow path and control means for controlling an opening of the flow control valve is used.

A third aspect of the present invention further restricts the configuration of the variable damping device, and is a case where a variable damping device according to a fourth aspect described below is applied to the vibration damping method according to the second aspect.

[0010] The variable damping device according to claim 4 of the present application includes a cylinder connected to one of the beam-column frame and the additional seismic element,
A piston having a rod that reciprocates in the cylinder and is connected to the other of the beam-column frame and the additional seismic element, a hydraulic chamber formed on both sides of the piston, and a flow path connecting the two hydraulic chambers And a flow control valve provided in the flow path,
A variable damping device having control means for controlling the opening degree of the flow control valve, wherein the control means controls the opening degree of the flow control valve to reduce the damping coefficient C to a minimum value C _min and a maximum value C _min.
is switchable between the _max, the two hydraulic each of the chamber pressure P ₁ (t), the hydraulic gauge is attached to measure P ₂ (t), further relative displacement of the cylinder and the rod δ A displacement meter for determining ₁ is provided, and the control means sets the damping coefficient C in the initial state to a maximum value _Cmax , and the following equation or equation: (dδ (t) / dt) · δ ₂ (t) <0 If (dδ (t) / dt) · (dδ (t−Δt) / dt) is satisfied, the value is switched to the minimum value C _min , and then the following equation: | dδ ₁ (t) / dt | <V _{0 Are} switched to the maximum value _Cmax when... Are satisfied, and then set so as to maintain the maximum value _Cmax until the expression or the expression is satisfied.

However, when C = _Cmax , dδ (t) / dt = d (δ ₁ (t) + δ ₂ (t)) / dt ... δ ₂ (t) = F (t) / K ₂ . Here, δ ₁ is the relative displacement between the cylinder and the rod of the variable damper, δ ₂ is the displacement of the additional seismic element at the variable damper installation position, and F is the damping force generated by the variable damper (F (t) = A
_{· (P 1 (t) -P} 2 (t)), A is the piston area, P
₁ (t) and P ₂ (t) are the hydraulic pressures in the hydraulic chambers on both sides of the piston, K ₂
Is the rigidity of the added seismic element.

In the structure equipped with this variable damping device, the system (device, control, control) is provided in a state where a damping force limiting mechanism is provided as shown in the equation to avoid the impact force at the time of switching to _Cmax . , in order to compensate for the time delay of the communication) it can be addressed by setting greatly according to V ₀ to it.

According to a fifth aspect of the present invention, in the variable damping device according to the fourth aspect, when the damping coefficient switches from the minimum value C _min to the maximum value C _max , the damping force F generated by the variable damping device increases beyond a set value. In this case, a case where a relief valve is provided in the flow path together with the flow control valve is limited.

[0014]

FIG. 1 shows an outline of an oil-sealed variable damping device 1 according to an embodiment of the present invention.
The main components are provided in a cylinder 2, a piston 3, a piston rod 4, hydraulic chambers 5a and 5b formed on the left and right sides of the piston 3 in the cylinder 2, and a flow path 6 connecting the two hydraulic chambers 5a and 5b. It has a flow control valve 7 and a controller 8 as control means for controlling the opening of the flow control valve 7.

A hydraulic pressure gauge 9 is provided in both hydraulic chambers 5a and 5b.
a, 9b are provided, and these oil pressure gauges 9a, 9b
Information of the hydraulic pressures P ₁ and P ₂ measured by the pressure sensor and the relative displacement δ ₁ of the cylinder 2 and the piston 3 measured by the displacement meter (not shown) are sent to the controller 8, and based on the information, the controller 8 Sends a control command to the flow control valve 7.

The flow control valve 7 has a maximum damping coefficient C _max when the opening degree command is fully closed, and a minimum damping coefficient C when the opening degree command is fully opened.
Give _min to the device.

In this example, a relief valve 10 is provided in parallel with the flow control valve 7 to prevent damage due to an impact force that occurs when the damping coefficient switches from _Cmin to _Cmax. The mechanism is such that the damping force F does not increase more than a certain value so as not to occur.

FIG. 2 shows the load between the layers in the steady state of the vibration control method using such a damping force F limiting mechanism.
It shows a deformation relationship. In this example, the limit value _Fmax of the damping force F is matched with F in FIG. 8 which is subject to structural constraints, but has a load-deformation relationship between layers that can achieve energy absorption exceeding the structural constraints. .

An example of a simulation analysis by setting a vibration model of one unit shown in FIG. 7B is shown below. Here specifications used was, M = 9800t, m = 9.8t , K 1 = 4t / cm, K 2 = 1t / cm, C max = 1000t / kine, C min = 0t / kine, F max = 10t , and the therefore the rigidity ratio is _{N = K 2 / K 1 =} 0.25,
Natural period only by K ₁ is about 10 seconds.

A sine wave having a natural period of 10 seconds and a maximum acceleration of 1 cm / sec ² is input to this vibration system for 50 seconds.

The displacement δ, velocity dδ / dt,
FIG. 3 (a) shows a control state based on the time history waveform of the damping force F.

The maximum displacement is about 4 cm, which is reduced to about 1/7 as compared with the displacement of 28 cm shown in FIG.

FIG. 4 shows the load-deformation relationship of the layers. This can be confirmed to have a load-deformation relationship substantially as shown in FIG.

The present invention is also effective when the rigidity ratio N is small, at which a large response reduction effect cannot be obtained by the ordinary control method.

For example, FIG. 5A shows a rigidity ratio N = 0.05.
Shows the time history waveforms of displacement, velocity, and damping force when this vibration control method is applied. Comparing this with the displacement of 24 cm in the case of the optimal passive damper shown in FIG. 5 (b), it can be seen that the displacement can be further reduced to about 12 cm by this control, which is about 12 cm.

FIG. 6 shows a case where the variable damping device 1 is installed on the stud 14 as an example of the installation of the variable damping device 1 when the rigidity ratio is small. As in this example, in the present invention, since the rigidity ratio is small, a sufficient effect can be exerted even in an installation method in which the effect cannot be expected, so that the degree of freedom in installing the vibration damping device is increased.

[0027]

According to the present invention, a variable damping device is installed in a beam-column structure, and more energy is stored and consumed in additional seismic elements such as braces, so that the response of the beam-column frame as a main frame can be reduced. .

Since the variable damping device controls the opening degree of the valve, it can be driven by a small amount of energy, and becomes an energy-saving vibration control structure.

This is particularly effective when the rigidity of the additional seismic element is smaller than the rigidity of the beam-column frame.

Further, by providing a limit value of the damping force, it is possible to prevent an impact from occurring at the time of variable damping switching.

[Brief description of the drawings]

FIG. 1 is a diagram showing an outline of a variable attenuation device according to an embodiment of the present invention.

FIG. 2 is a graph showing an outline of a load-deformation relationship in the vibration control method of the present invention.

3A is a graph showing a state of control based on a time history waveform of a displacement δ, a velocity dδ / dt, and a damping force F in a simulation of the vibration control method of the present invention, and FIG. 6 is a graph showing a time history waveform of a displacement δ.

FIG. 4 is a graph showing a load-deformation relationship of a layer in the simulation of FIG. 3;

FIG. 5 shows the results of a simulation in the case where the rigidity of the additional seismic element is small. FIG. 5 (a) shows the time of displacement δ, velocity dδ / dt, and damping force F according to the vibration control method of the present invention. 7B is a graph showing a state of control using a history waveform, and FIG. 7B is a graph showing a time history waveform of a displacement δ when an optimal passive damper is installed.

FIG. 6 is a schematic view showing a case where a variable damping device is installed between a beam-column frame and a stud as an example of an additional seismic element having low rigidity.

FIG. 7 (a) is a diagram showing a general beam-column frame provided with a variable damping device, and FIG. 7 (b) is a vibration model diagram thereof.

FIG. 8 is a graph showing an outline of a load-deformation relationship under a structural constraint in a conventional vibration damping method using a variable damping device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Variable damping device, 2 ... Cylinder, 3 ... Piston, 4 ...
Piston rod, 5a, 5b ... hydraulic chamber, 6 ... flow path, 7 ...
Flow control valve, 8 ... controller, 9a, 9b ... oil pressure gauge,
10 relief valve, 11 pillar, 12 beam, 13 brace, 14 stud

Claims (5)

[Claims] An additional seismic element is provided in a column-beam frame of a structure, a variable damping device is installed between the column-beam frame and the additional seismic element, and a beam-column when an external vibration force such as an earthquake is input to the structure. By controlling the damping coefficient of the variable damping device based on the response of the frame, etc., the damping force is applied to the beam-column frame to reduce the response of the structure. A structure, wherein the damping coefficient of the variable damping device is controlled so as to increase the damping force of the variable damping device while increasing the vibration of the additional seismic element using the relative vibration with respect to the column-beam frame. How to control the vibration. 2. The variable damping device according to claim 1, wherein the variable damping device is a cylinder connected to one of the column-beam frame and the additional seismic element, and reciprocates in the cylinder to be connected to the other of the column-beam frame and the additional seismic element. A piston having a rod, hydraulic chambers formed on both sides of the piston, a flow path connecting the two hydraulic chambers, a flow control valve provided in the flow path, and an opening degree of the flow control valve. The method of controlling a structure according to claim 1, further comprising control means for controlling. 3. The variable damping device controls a damping coefficient C to a minimum value C _min and a maximum value C by controlling an opening of the flow control valve.
_{The maximum} damping coefficient C of the variable damping device is defined as a maximum value _Cmax , and the following equation or equation: (dδ (t) / dt) · δ ₂ (t) < 0 satisfies (dδ (t) / dt) · (dδ (t−Δt) / dt)..., Then switches to the minimum value C _min , and then the following equation: | dδ ₁ (t) / dt | <V 3. The method according to claim 2, further comprising switching to the maximum value _Cmax when ₀ ... Is satisfied, and then maintaining the maximum value _Cmax until the expression or the expression is satisfied. However, in the state of C = _Cmax , dδ (t) / dt = d (δ ₁ (t) + δ ₂ (t)) / dt ... δ ₂ (t) = F (t) / K ₂ δ ₁ is the relative displacement between the cylinder and the rod of the variable damper, δ ₂ is the displacement of the additional seismic element at the position where the variable damper is installed, and F is the damping force generated by the variable damper (F (t) = A · (P
_{1 (t) -P 2 (t} )), A is the piston _{area, P 1 (t), P} 2 (t) is a piston on both sides of the hydraulic chamber of the hydraulic, K ₂ is the stiffness of the additional seismic elements. 4. A cylinder coupled to one of the beam-column frame and the additional seismic element, a piston having a rod reciprocating in the cylinder and coupled to the other of the column-beam frame and the additional seismic element, A hydraulic chamber formed on both sides of the piston, a flow path connecting the two hydraulic chambers, a flow control valve provided in the flow path, and control means for controlling an opening of the flow control valve. In the variable damping device, the damping coefficient C can be switched between a minimum value C _min and a maximum value C _max by controlling the opening degree of the flow control valve by the control means. An oil pressure gauge for measuring ₁ (t) and P ₂ (t) is provided, and a displacement gauge for obtaining a relative displacement δ ₁ between the cylinder and the rod is provided. The coefficient C is defined as a maximum value _Cmax , and the following equation or Formula If (dδ (t) / dt) · δ 2 (t) <0 ... (dδ (t) / dt) · (dδ (t-Δt) / dt) ... satisfied, the minimum value C _min switching, then the following _{equation, | dδ 1 (t) /} dt | <V 0 ... switched to the maximum value C _max in a state to be satisfied, then maintain the maximum value C _max to formula or formula is satisfied A variable damping device characterized by being set as follows. However,
Under the condition of C = _Cmax , dδ (t) / dt = d (δ ₁ (t) + δ ₂ (t)) / dt ... δ ₂ (t) = F (t) / K ₂ where δ ₁ Is the relative displacement between the cylinder and the rod of the variable damper, δ ₂ is the displacement of the additional seismic element at the position where the variable damper is installed, and F is the damping force generated by the variable damper (F (t) = A · (P
_{1 (t) -P 2 (t} )), A is the piston _{area, P 1 (t), P} 2 (t) is a piston on both sides of the hydraulic chamber of the hydraulic, K ₂ is the stiffness of the additional seismic elements. 5. The damping coefficient changes from a minimum value C _min to a maximum value C _min.
5. The variable damping device according to claim 4, wherein a relief valve is provided in the flow path together with the flow control valve so that the damping force F generated by the variable damping device does not increase beyond a set value when switching to _max. .