JPH0413516B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a variable rigidity device used in a building frame with a vibration damping structure, which adjusts the rigidity of the building frame according to external forces such as earthquakes and wind input to the building. This is to change the environment and deal 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 seismic attenuation structures 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 There are methods such as creating slits in pillars, etc. to adjust the rigidity of the building to its optimum level.

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 earthquake-resistant structure against natural external forces such as earthquakes and wind, and because buildings have a specific natural frequency, they cannot resist resonance development against uncertain inputs such as earthquakes. You can't avoid it.

In contrast, in Japanese Patent Application No. 61-112026 (Japanese Patent Application 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 resistance 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 variable rigidity device for a building frame of the present invention is used in the above-mentioned vibration control method within the column and beam structure, floor slab structure, etc., and by freely controlling the deformation of the frame during an earthquake, it can improve the structure of the building. The purpose of this is to reduce the response of earthquakes and prevent earthquake disasters in buildings, as well as protect people and machinery inside from discomfort caused by earthquakes, vibration disturbances, etc.

[Structure of the invention]

Hereinafter, an overview of the present invention will be explained using reference numerals in the drawings corresponding to the embodiments.

This invention uses wires such as steel cables, PC steel wires, and piano wires, or cable members 3a such as chains, ropes, and belts as braces 3 that connect two points in the structure, and uses a tension device 5 to tighten the cable members 3a. The tension of the structure can be adjusted to freely control the deformation of the structure during an earthquake.

Furthermore, in the variable rigidity device of the present invention, in addition to the cable member 3a as the brace 3 and the tension device 5, a buffer 4 is interposed between the cable member 3a and at least one of the two points in the structural surface described above. There is.

By adjusting the tension of the cable member 3a with the tension device 5, a predetermined tension can be applied to the brace 3 in its axial direction. Further, the buffer 4 has a predetermined stroke in the axial direction as the brace 3, and the damper function of the buffer 4 allows the brace 3 to work as a damper brace.
When the rigidity is suddenly changed, the buffer 4 can function as an original shock absorber. Batsuhua 4
A spring type type or a hydraulic type type can be used, but the type is not particularly limited.

The rope-like member 3a constituting the brace 3 is a loop-like member, and if one end is hung on the buffer 4 and the other end is hung on the pulley 7, the rope-like member 3a
It is possible to reduce the frictional force, etc. that acts on the

The buffer 4 and pulley 7 are attached to the column-beam joint, or to the gusset plate 6 or the like provided at the column 1 position in the case of a floor slab structure. The tensioning device 5 can also be attached to the gusset plate 6 or the like, but it may also be separated and attached separately.

[Function] The cable member 3a of the brace 3 is prestressed by the amount of deformation of the spring, etc. of the buffer 4 by setting the buffer 4 under tension so as to push in only half of its stroke (see Fig. 1). has been introduced into the cable member 3a, and the brace 3 can bear the corresponding compressive force. That is, the stiffness of the brace 3 is low in both compression and tension directions due to the spring of the buffer 4, etc., and the relationship between load and deformation in the brace 3 becomes linear. Note that the stroke of the buffer 4 is 2 in the structural plane connected by the brace 3.
The allowable displacement between points, that is, the allowable compressive deformation of the brace 3 when viewed as a frame component (in the case of the cable member 3a, tension force due to prestress is introduced) and the allowable tensile deformation. The total shall be greater than or equal to the total.

The cord-like member 3a of the brace 3 is tightened by the tensioning device 5.
By tensioning the springs, etc. of the buffer 4, it is possible to make them completely adhere to each other (see Fig. 2).
At this time, the rigidity of the brace 3 against tension is the rigidity of only the cable member 3a, resulting in a brace with high rigidity against tension. On the other hand, compression remains as described above. FIG. 7 shows the relationship between the load applied to the brace 3 and the deformation at this time.

Due to the damper function of buffer 4, in the above state, it acts as a brace and damper with low rigidity in both tension and compression, and in state, it acts as a brace and damper with high rigidity in tension.
During compression, it acts as a brace and damper with low rigidity.

Shock that occurs when the stiffness suddenly changes due to the tensioning device 5 (particularly the shock caused by the force that is released as soon as the force borne by the high stiffness is transferred to the low stiffness)
can be absorbed by the buffer 4's original function as a buffer.

〔Example〕

Next, the illustrated embodiment will be described.

FIGS. 1 to 3 show examples in which the variable rigidity device of the present invention is applied to a column and beam structure.

In this embodiment, gusset plates 6 are provided at diagonal positions within the structural surface of the column and beam, and a pulley 7 is attached to one side, and a buffer 4 and tension device 5 are attached to the other side, and the pulley 7 and buffer 4 are connected to each other as a loop-shaped cable member. ,
A brace 3 is constructed by spanning the wire 3a.

The tension device 5 rotates the bundle material 5a by operating the motor 8, expands the gap between the loop-shaped wires 3a at both ends of the bundle material 5a, tensions the wire 3a, and returns the bundle material 5a. This allows the tension to be released. The bundle material 5a rotates around a rotating shaft 9 attached to the gusset plate 6, and as shown in FIG.
When a and the brace 3 are in series, there is no tension from the tensioning device 5, and when the bundle 5a is perpendicular to the brace 3 as shown in FIG. 2, the maximum tension is introduced.

The buffer 4 may be of a hydraulic type or of various other types, but for convenience of explanation, it will be described below as a spring as shown in the drawings. Note that other formats can be considered in the same way. As shown in FIG. 1, when there is no tension from the tension device 5, the spring of the buffer 4 is compressed in advance, and the wire 3a of the brace 3 is in a neutral state with respect to the forces in the tension and compression directions, that is, a certain amount of tension is applied to the wire 3a of the brace 3. Leave it in a state where it is introduced as prestress. At this time, the rigidity of the brace 3 has the rigidity of the series spring of the wire 3a and the buffer 4.

In a tense state as shown in Figure 2, the buffer 4
The springs are in close contact with each other, and the stiffness of the brace 3 against compression remains the same as that of the series spring of the wire 3a and the buffer 4, but against tension, the stiffness of the wire 3a alone becomes high, resulting in high rigidity. In addition, in the mechanism for pushing out or returning the distance between the loop-shaped wires 3a, even if the resistance to pushing out is large during tension and it is difficult to change the rigidity instantaneously, when the structure is vibrating, The force acting on brace 3 is then transferred to compression,
The action of pushing and spreading becomes easier, and the rigidity remains unchanged for the next tension. FIG. 6 shows this relationship.

The embodiments shown in FIGS. 4 and 5 have hydraulic or pneumatic cylinders 10, 11 instead of the tensioning device 5 by rotating the bundle material 5a in the above-described embodiment.
was used as a tension device. Further, in the above embodiment, the wire 3a is stretched by expanding the interval between the loop-shaped wires 3a, but it is also possible to tighten the wire 3a by simply pulling the end of the wire without using the loop-shaped wire. It can be something that makes you nervous. In that case, in order to compress the spring of the buffer 4 in advance and make it in a neutral state against both tension and compression forces, apply tension equal to the prestress using the tension device, and then introduce or release the tension based on that tension. will be carried out.

Furthermore, although the above is a case of one-sided braces, by providing two braces 3 that intersect within the structural plane (see FIG. 10), the rigidity change pattern of the frame becomes as shown in FIG. 8. In other words, when there is no tension from the tensioning device 5, the load and displacement have a linear relationship, which is the sum of the rigidity of the frame and the aforementioned spring rigidity, and when tension is applied and the spring rigidity stops working, the brace This is a combination of the high rigidity of the wire 3a itself and the rigidity of the frame.

Moreover, if the interval between the loop-shaped wires 3a is expanded, the bundle material 5a or the cylinders 10, 11
A component force equivalent to the brace tensile force is applied to the components, but since the angle of the brace 3 due to these is gentle, the component force is sufficiently small and only needs to be strong enough to resist it. In the embodiment shown in FIG. 9, a pulley or pin 12 is provided on the gusset plate 6 so that the angle .theta. on both sides of the bundle material 5a due to the spreading of the wire 3a is made equal. Further, in this embodiment, the tensioning device 5 is provided not on the buffer 4 side but on the pulley 7 side.

The above has been explained in relation to the structural surface surrounded by the beams 2 of a pair of columns 1, but when applied to a multi-story building as shown in Fig. 10, a large number of this device are arranged, and Stiffness can be changed.

[Effects of the Invention] By combining the brace constituted by the cable member and the tension device, deformation of the frame during an earthquake can be controlled.

When tension force is not introduced or increased, the damper function of the buffer acts as a brace and damper with low stiffness during both tension and compression, and when tension force is introduced or increased, it acts as a brace and damper with low stiffness during tension. When compressed, it acts as a brace and damper with low rigidity.

The shock that occurs when the stiffness suddenly changes due to the tensioning device,
In particular, the shock caused by the force released as soon as the force borne by the high rigidity is transferred to the low rigidity can be absorbed by the buffer's original function as a shock absorber.

A tensioning device controlled by a computer or the like changes the stiffness of the braces, making it possible to control the deformation of the entire building according to individual seismic characteristics.
This increases the safety of the building and creates a comfortable living space with less shaking.

[Brief explanation of drawings]

Figures 1 and 2 are front views showing one embodiment of the present invention, Figure 3 is a side view of the tensioning device, and Figure 4 is a side view of the tensioning device.
5 and 5 are front views showing modified examples of the tensioning device, FIG. 6 is a graph for explaining the action of the device of the present invention, and FIGS. 7 and 8 are loads acting on the brace and deformation of the brace. FIG. 9 is a front view showing another embodiment of the present invention, and FIG. 10 is a front view showing an example of application to a multi-story building. 1...Column, 2...Beam, 3...Brace, 3a...
...wire, 4...batshua, 5...tension device,
6...Gusset plate, 7...Pulley, 8...
...Motor, 9...Rotating shaft, 10...Cylinder, 11...Cylinder, 12...Pin.

Claims (1)

[Scope of Claims] 1. A cable-like member as a brace connecting two points in the structural plane, a tensioning device for applying a predetermined tension in the axial direction as a brace of the cable-like member, and at least one of the two points. 1. A variable rigidity device for a building frame, characterized in that the device comprises a buffer interposed between the cable member and the cable member and having a predetermined stroke in the axial direction as a brace for the cable member. 2 The stroke of the buffer is
The variable rigidity device for a building frame according to claim 1, wherein the distance between the points is greater than or equal to the allowable displacement amount. 3. The variable rigidity device for a building frame according to claim 1 or 2, wherein the cable member is a steel cable. 4. The variable rigidity device for a building frame according to claim 1 or 2, wherein the cable member is a chain. 5 Claim 1 in which the cable member is a rope
The variable rigidity device for a building frame according to item 1 or 2. 6 Claim 1 in which the rope member is a belt
The variable rigidity device for a building frame according to item 1 or 2.