JPH0370071B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to an axially variable rigidity material used in a building frame with a vibration-damping structure, in which the stiffness of the member changes in response to external forces such as earthquakes and wind that are input to the building. This changes the rigidity to cope with earthquakes, etc.

[Conventional technology]

Conventionally, in the seismic design of high-rise buildings and important structures, dynamic design has been performed to check safety by calculating the ground movement and building response during an earthquake.

Earthquake resistance methods include seismic isolation or attenuation construction methods in which laminated rubber bearings or dampers are interposed between the building and the foundation, methods that consume earthquake energy by destroying non-main building components, walls or columns. There is a method to adjust the rigidity of the building to the optimum level by creating slits in the building.

By the way, confirmation of the safety of buildings designed using current seismic design methods in the event of an earthquake is based on the basic idea that the energy absorbed by the hysteresis characteristics associated with plasticization of the structure exceeds the seismic energy acting on the structure. However, this has the problem of reliability regarding the history loop characteristics.

In addition, all conventional methods provide a passive seismic structure against natural external forces such as earthquakes and wind, and because buildings have a specific natural frequency, they do not allow resonance phenomena to occur against uncertain inputs such as earthquakes. You can't avoid it.

In contrast, in Japanese Patent Application No. 61-112026 (Japanese Unexamined Patent Publication No. 62-268479), the applicant proposed a method based on the judgment of a response prediction system based on the detected seismic motion, rather than the passive seismic method described above. We are proposing a vibration damping method that changes the rigidity of the building itself to bring it out of the resonance region or into a state with less resonance, thereby ensuring the safety of the building, its equipment, residents, etc.

In the above seismic control method, a control device is installed in all or part of columns, beams, braces, walls, and their joints, or between a building and the foundation or an adjacent building, so that the connection state can be changed according to computer commands. , Damping the building is done as follows.

The occurrence of an earthquake is detected by earthquake sensing devices placed in both narrow and wide areas around buildings, and the observation data is transmitted to a computer via wired and wireless communication networks. Wide-area earthquake sensing equipment connects seismometers at existing earthquake observation points or specially installed equipment using micro-wires or telephone lines. In addition, narrow-area earthquake sensing devices consist of seismometers installed around buildings or in the surrounding ground, and vibration sensors installed at the base of buildings or inside buildings, and the effects of wind force etc. are detected by vibration sensors inside buildings.

For detected earthquakes, a computer determines the scale of the earthquake, analyzes frequency characteristics, predicts the amount of response, etc., and determines whether or not to control the vibration of the building, and if so, the amount of control to avoid resonance. The judgment is made based on the one that provides the optimum stiffness (natural frequency) with a small amount of seismic response.

The commands from the computer are transmitted to the control devices in each part of the building, and the control devices are operated so that the stiffness of the building reaches the optimal stiffness based on the computer's predictions. The connection state can be adjusted by turning the fixed state and uncoupled state on and off using hydraulic mechanisms, electromagnets, etc., and in addition to the fixed state and disconnected state,
It is conceivable to use a hydraulic mechanism or a special alloy to adjust the introduction of tension force and fixation at an arbitrary position.

In addition, vibration sensors placed inside the building will
The amount of response in each part of the building as well as the actual vibration when controlled can be detected, and this can be fed back to correct the amount of control.

[Purpose of the invention]

The axially variable rigidity material of the building frame of the present invention is used for braces, columns, etc. in the above-mentioned vibration control method to change the axial rigidity and cope with earthquakes, etc. . Note that the present invention is not limited to use in the above-mentioned vibration damping method, but can also be used to improve the above-mentioned method, or simply to change rigidity.

[Structure of the invention]

This invention will be explained below using the dynamic model shown in FIG.

As shown in FIG. 2, the variable rigidity material A of the present invention has a dogleg-shaped main member 1, 2 which has a common point receiving axial force N (indicated by pins 4a, 4b in the figure), and a pin 5a between each. , 5b, and pins 5a, 5
The material axis of the connecting member 3 is perpendicular to the direction of the axial force N, and can be expanded and contracted by a drive device 6 that applies force in this direction. Member 1a constituting main members 1 and 2,
The cross sections of the members 1b, 2a, 2b and the members 3a, 3b constituting the connecting member 3 are determined so as to have basic axial rigidity capable of resisting the axial force N as a stable structure.

The basic rigidity as an axial force resistance material is determined by the angle θ (axial direction and main members 1 and 2) of bending into a dogleg shape when at rest.
It can be selected depending on the angle formed by the members constituting the connecting member 3) and the basic rigidity of the connecting member 3. That is, even when the braking force of the drive device 6 of the connecting member 3 is not considered, the basic rigidity can be arbitrarily changed by θ.

As the drive device 6, a hydraulic actuator with a servo valve, a digital hydraulic actuator using an electric pulse motor, or a ball screw is used, and the bolt is rotated by the electric servo motor to perform the connection. An electromagnetic linear motor or the like can be considered as a device that changes the distance between the members 3a and 3b of the member 3a, and other devices that require small power. It is effective to apply the control force P by these drive devices 6 when it is desired to change the rigidity from time to time, such as to avoid a resonance phenomenon of the building due to an earthquake. In other words, the drive device 6 can be automatically controlled based on a computer control program, and the natural period of the building as a whole can be adjusted by changing the rigidity, connection state, etc. of members in each part of the building in response to external vibrational forces such as earthquakes. Resonance can be avoided by changing the

Regarding the basic rigidity of the connecting member 3, if necessary, a coil spring or the like may be interposed in parallel with the drive device 6 to ensure a predetermined rigidity even when the drive device 6 does not operate.

[Effect]

As mentioned above, when θ is selected, the basic stiffness Ko is uniquely determined so that the deformation in the direction of the axial force N is proportional to the axial force, but the control force P by the drive device 6 provided on the connecting member 3 changes the basic stiffness Ko. It is something that can be changed. That is, by further adding or subtracting the control force P to the expansion and contraction of the connecting member 3 due to the member stress of the connecting member 3 determined geometrically by the axial force N, the dogleg-shaped main member 1 is , 2 intermediate pin 5
The deformation in the direction of the axial force N can be changed by increasing or decreasing the deformation in the direction perpendicular to the direction of the axial force N at the joint a, 5b.

The basic stiffness Ko in the direction of action of the axial force N uniquely determines the relationship between the axial force N and the deformation δ in the direction of action of the axial force, as shown in equation (1) below (see Figure 3 a).
When the control force P is applied to the connecting member 3 (see Fig. 3b), the change can be changed by △δ, which is the same as changing the stiffness K as shown in equation (2) below. Become.

Ko=N/δ...(1) K=N/δ+△δ……(2) 〔Example〕 Next, the illustrated embodiment will be described.

FIGS. 1a to 1c show an example of the structure of the variable rigidity material A. FIG. Opposing dog-shaped main members 1 and 2
The members 1a, 1b and the members 2a, 2b are respectively joined by pins 5a, 5b, and both ends receiving axial force are joined by a common pin 4a, 4b. In this embodiment, the cross section of each member 1a, 1b, 2a, 2b is the first
Although it has an H-shaped cross section as shown in Figure c, it is not necessary to be limited to this.

A connecting member 3 connects the joint between the pins 5a and 5b. The connecting member 3 is, for example, a first
As shown in FIG.
By rotating the bolt 7 by the nut 8 fixed to the member 3a, the member 3a moves away from or approaches the other member 3b,
A control force P acts. In this way, the motor 6a
A control force can be obtained by converting the rotation of the bolt 7 into a linear motion of the bolt 7 and applying acceleration to the doglegged main members 1 and 2. The above-mentioned bolt 7 and nut 8 can be connected using a ball screw (a device in which the male and female screws are aligned in the same position, a ball is inserted into the groove created by the screw, and a return groove is provided so that the ball can circulate). If a replacement structure is used, that is, a ball screw is used for the threaded part of the members corresponding to the bolt and nut, friction can be reduced and driving efficiency can be increased. 9 in the figure is a stopper. FIG. 1d shows an example in which a hydraulic cylinder 6b having a servo valve is used instead of the electric servo motor 6a, and can be directly controlled by hydraulic pressure.

As an example, if we consider the case where the power N is a tensile force,
By operating the drive device 6 and exerting a control force in a direction that narrows the distance between the pins 5a and 5b, the rigidity K becomes smaller according to the above-mentioned equation (2). Conversely, pin 5
By applying the control force in a direction that increases the distance between a and 5b, Δδ in equation (2) becomes a negative value, and the rigidity K increases. Even when the axial force N is a compressive force, the change in stiffness K can be determined from equation (2).

Figure 4 shows an example in which variable stiffness material A is applied to a brace, and Figure 5 shows an example in which it is used on both sides of a long-term axial force column 10 on the lowest floor of a building, and used as a resistance column against overturning moment during an earthquake. . The rigidity K of the variable rigidity member A is controlled by the control force generated by the operation of the drive device 6.
changes, and resonance can be avoided. 11 in the diagram
Shear walls or braces.

In Figures 6a to 6c, the capitals and bases of columns are connected with pins on the lowest floor of a building, and the variable rigidity material A of the present invention is used as a brace. If the basic stiffness of the connecting member is made extremely small, the horizontal stiffness of the lowest layer is determined by the control force. The rigidity of the braces should be high against lateral forces such as wind that enter from the building side (No. 6)
(see figure a). In addition, the control force is adjusted so that the rigidity of the brace becomes low against earthquakes and other forces that enter from the ground (see Figures 6b and 6c). In other words, it becomes a seismic isolation device.

The above mechanism is basically the same as long as the column is used in a normal building, instead of using a pin connection at the joint, the horizontal rigidity of the column increases slightly even if the joint is rigidly connected. Rigid joints are advantageous in terms of economy and workability, as they facilitate assembly when manufacturing and erecting steel frames. In addition, use as a seismic isolation device, etc.
For large deformations due to free vibrations that occur when used gently, the control force provided by the drive device 6 can be used as a damper to cancel out the vibrations.

[Effects of the Invention] By applying a control force in a direction perpendicular to the axial force at the pin joint position in the middle of the dogleg-shaped main member, the rigidity as an axial force resisting material can be changed.

By controlling changes in the rigidity of variable-rigidity materials used in building frames using computers, etc., it is possible to vary the natural period of the building according to individual seismic characteristics, thereby suppressing large deformations of the building due to resonance phenomena.

By using a computer-based vibration control method, a comfortable living space with no resonance and less shaking can be created.

[Brief explanation of drawings]

Figures 1 a to d show an embodiment of the present invention, and Figures 1 a, b, and c are front views, and -
Sectional view, and - Sectional view, Figure 1 d -
2 is an explanatory diagram showing a dynamic model; FIGS. 3 a and b are explanatory diagrams showing the relationship of deformation; FIG. 4 is a front view showing an example of application to a brace; FIG. 5 is a front view showing an example of application to a moment resistance column, and FIGS. 6a, b, and c are front views showing the effect when applied to a brace on the lowest floor of a building. A...Variable rigidity material, 1, 2...Main member, 3...
Connection member, 4a, 4b, 5a, 5b...pin, 6
...Drive device, 6a...Motor, 6b...Hydraulic cylinder, 7...Bolt, 8...Nut, 9...
...Stopper, 10...Long-term axial force column, 11...
Shear walls or braces.

Claims (1)

[Scope of Claims] 1. Pin joints are formed between mutually opposing dogleg-shaped main members that share a common point of receiving axial force at the ends of both materials, and the pin joint positions can be expanded and contracted by the operation of a drive device. An axially variable rigidity member, characterized in that the material is connected by a connecting member having a shape, and by expanding and contracting the connecting member, it is possible to introduce a control force in a direction perpendicular to the axial force. 2. The connecting member is 2 connected via a drive device.
The axially variable rigidity member according to claim 1, wherein the axially variable rigidity member is made of a member, and the distance between the two members is controllable by the operation of the drive device. 3. The axially variable rigidity member according to claim 1 or 2, wherein the drive device is a hydraulic cylinder having a servo mechanism. 4. The axially variable rigidity member according to claim 1 or 2, wherein the drive device is an electric or hydraulic stepping cylinder.