JPH0686774B2 - Variable bending stiffness device for structures - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a variable bending rigidity device used for a seismic control structure, and a frame, particularly a column, according to an external force such as an earthquake or wind input to the structure. The expansion and contraction rigidity of the is changed to cope with earthquakes, etc., and it is suitable for vibration damping of so-called pencil buildings, steel towers, etc., which are mainly fine structures with high bending deformation.

[Conventional technology]

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

Seismic resistant methods include seismic isolation or damping methods in which laminated rubber bearings and dampers are interposed between the building and foundation, methods of consuming seismic energy by destroying non-major components of building components, walls or columns. Slits etc. are provided,
There is a method to adjust the building to the optimum rigidity.

By the way, the confirmation of the safety of a building designed by the current seismic design method during an earthquake is based on the basic idea that the absorbed energy due to the hysteresis characteristic accompanied by plasticization of the structure exceeds the earthquake energy acting on the structure. However, this has a reliability problem with respect to the history loop characteristic.

In addition, all of the conventional methods provide a passive seismic resistant structure against natural external forces such as earthquakes and winds, and because the building has a specific natural frequency, resonance phenomena are generated in response to uncertain inputs such as earthquakes. You cannot avoid it.

On the other hand, the applicant has filed Japanese Patent Application No. 61-112026 (Japanese Patent Laid-Open No. 62-26).
8479 gazette), the rigidity of the building itself is actively changed based on the judgment of the response prediction system based on the detected seismic motion instead of the passive seismic resistance method as described above. We have proposed a seismic control method for the safety of the building, the equipment inside the building, and the residents.

In the above seismic control method, a control device whose connection state is changed by a computer command is installed between all or part of columns, beams, braces, walls and their joints, or between the building and the foundation or an adjacent building. , Damping the building is done as follows.

An earthquake detector is used to detect the occurrence of an earthquake in a narrow area and a wide area around the building, and the observation data is transmitted to a computer via a wired or wireless communication network. The wide area seismic detector is connected to the seismograph at the existing seismic observation point or a specially installed seismometer by a micro line or a telephone line. The narrow-area seismic sensing device is composed of a seismograph installed around the building or in the surrounding ground, and a vibration sensor installed in the building base or inside the building. The influence of wind force is detected by the vibration sensor inside the building.

Regarding the detected earthquake, the computer determines the scale of the earthquake, analyzes the frequency characteristics, predicts the response amount, etc., bypasses the resonance regarding whether or not to control the building vibration, and the control amount when it should be controlled, It is judged that it gives the optimum stiffness (natural frequency) with a small amount of seismic response.

The computer command is transmitted to the control device of each part of the building, and the control device is operated so that the rigidity of the building becomes the optimum rigidity based on the prediction of the computer. For adjusting the connected state, the fixed state and the released state are adjusted by turning on and off with a hydraulic mechanism, electromagnet, etc., and the hydraulic mechanism is used for the outside of the fixed state, the released state, the introduction of tension force and the fixing at any position. Alternatively, a special alloy or the like may be used for adjustment.

Further, the vibration sensor arranged in the building can detect the response amount in each part of the building and the actual vibration when the control is performed, and by feeding back this, the control amount can be corrected.

[Problems to be Solved by the Invention]

By the way, the deformation of the structure has a shear deformation component and a bending rigidity component, and the conventionally considered variable rigidity device is mainly effective for the former deformation. However, the height is higher than the width of the building, like the so-called pencil building and steel tower,
In a slender structure, the latter flexural rigidity component is predominant, so suppressing this bending deformation is important for damping the structure.

The present invention is intended to improve the safety of the structure in the event of an earthquake by controlling this bending rigidity component.

[Means for Solving the Problems]

The outline of the present invention will be described below with reference to FIGS. 1 and 2.

The variable bending stiffness apparatus of the present invention is provided with a shaft member 4 between upper and lower support beams 5 projecting from a column 1 of a structure, along the column 1, substantially parallel to the column 1, and the shaft member 4 and the support beam 5. The jack 6 is interposed in at least one of the joints with the, and the shaft member 4 is expanded and contracted by the jack 6 with respect to the pillar 1 so that the expansion and contraction rigidity of the pillar 1 can be supplementarily changed.

That is, by operating the jack 6 at the time of an earthquake or the like, the effect of the shaft member 4 on the expansion and contraction rigidity of the column 1 is controlled, and the rigidity of the entire structure is controlled by controlling the bending rigidity component to suppress the response. It is what

The shaft member 4 is a member for restraining deformation of the pillar 1, and is not limited to a pillar material such as a steel pipe, shaped steel, etc. that resists both compression and tension. A wire such as a wire that resists only tension may be used.

[Action]

When an earthquake etc. acts on a tall building as shown in Fig. 9,
Bending deformation as shown in Fig. 10 occurs, the pillar 1 on one side of the building expands, and the pillar 1 on the opposite side contracts.

In the present invention, by expanding and contracting the shaft member 4 provided substantially parallel to the pillar 1, it is possible to restrain the expansion and contraction of the pillar 1 on both sides as shown in FIG.

That is, for bending deformation as shown in FIG. 10, by extending the shaft member 4 with respect to the column 1 on the right side of the figure, the column 1
The contraction of the column 1 can be restricted, and the extension of the column 1 can be restricted by contracting the shaft member 4 for the column 1 on the left side in the drawing.
With respect to the deformation in the opposite direction, the deformation can be restrained by the reverse operation.

〔Example〕

 Next, the illustrated embodiment will be described.

FIG. 3 and FIG. 4 show concrete examples,
At the height of the beam 2 in the building, the support beam 5 is projected to the outside of the pillar 1, and the shaft member 4 made of steel pipe is installed between the upper and lower support beams 5 via the hydraulic jack 6.

When a compressive force acts on the column 1 due to the bending deformation component acting on the structure, the hydraulic jack 6 is extended to push the upper and lower support beams 5 via the shaft member 4 along the column 1. A spreading force is applied, a part of the compressive force acting on the column 1 is canceled by the bending deformation component, and the contraction of the column 1 can be suppressed. Further, when the tensile force acts on the column 1, the hydraulic jack 6 is returned, so that a part of the tensile force acting on the column 1 is offset and the extension of the column 1 can be suppressed. The control of the hydraulic jack 6 is performed by a computer or the like, and resonance and excessive deformation are prevented from occurring depending on the vibration wave input momentarily and the deformation state of the structure.

FIG. 5 shows an arrangement example of the shaft member 4 in a horizontal section. For bending moment, it is efficient to install the shaft member 4 on the pillar 1 along the outer periphery of the building as shown in the figure. Is. Similarly, in the case of a steel tower or the like, it is preferable to dispose the shaft member in the column portion along the outer circumference.

For which shaft member 4 is effective or not,
The computer determines the periodic component of the earthquake motion and the state of the building, and then issues a variable stiffness command.

6 to 8 show an example of a method of installing the shaft member. First, the support beam 5 is provided in a cantilever form on the outer periphery of the building (see FIG. 6). Next, the drive device such as the hydraulic jack 6 is set on the lower support beam 5 (see FIG. 7). Finally, the shaft member 4 is sandwiched between the hydraulic jack 6 and the upper support beam 5 to complete the setting.

An example of the control procedure in the basic control system is as follows.

Seismic motion detection Seismic motion analysis Variable bending stiffness command Variable bending stiffness device operation Building bending stiffness change In reducing the building response by de-resonating with the earthquake motion, in the case of a building cycle that deviates from the dominant period component of the earthquake motion Select rigidity and issue a command.

Regarding this, specifically, as shown in FIGS. 12 and 13, two orthogonal directions (X and Y directions) are independently controlled. That is, the optimum rigidity is selected for each direction, and the hydraulic jack and other drive devices are operated accordingly. Figures 12 and 13 correspond to the plane section of a floor of the building, and the components in the X direction of the earthquake motion are shown in Figure 12.
X _1, bending by to twist the shaft member of X ₂ rows moment M _X
To increase the rotational rigidity. Similarly in the Y direction, the shaft members in the Y ₁ and Y ₂ rows in FIG. 13 are effective to increase the resistance to the bending moment M _Y and increase the rotational rigidity.

[Advantages of the Invention] Since the bending deformation component generated in a structure due to a horizontal external force such as an earthquake can be suppressed by the control of the shaft member along the column, excessive deformation of the structure is prevented particularly in a tall building. However, the safety of the building can be improved.

As with other vibration damping construction methods, the rigidity of the entire structure can be changed according to the external vibration force, resonance can be avoided, and the effect of an earthquake or the like can be minimized.

Since the control is performed by the shaft member along the pillar, the correspondence with the pillar to be controlled is clear and efficient control is possible.

[Brief description of drawings]

FIG. 1 is a schematic view showing the basic concept of the present invention, FIG. 2 is a schematic view showing a conventional way of thinking in a vibration control structure, FIG. 3 is a side view showing a concrete embodiment, and FIG. FIG. 5 and FIG. 5 are horizontal sectional views showing an example of the plane arrangement of the shaft member, and FIG.
Figures to 8 are side views showing the installation procedure of the apparatus, and Figures 9 to
FIG. 11 is a schematic view for explaining the operation, FIGS. 12 and 13
The figure is a perspective view for explaining two-way control. 1 ... Pillar, 2 ... Beam, 3 ... Brace, 4 ... Shaft member,
5 ... Support beam, 6 ... Jack

Claims (1)

[Claims] 1. An upper and lower support beam projecting from a column of a structure, a shaft member installed between the support beams in a direction substantially parallel to the column to supplementally change the expansion and contraction rigidity of the column, and the shaft member. And at least one of the joints between the supporting beam and the supporting beam, and is composed of a jack that is expandable and contractible in the longitudinal direction of the shaft member
A variable bending rigidity device for a structure, wherein the degree of effect of the shaft member with respect to the expansion and contraction rigidity of the column can be controlled by operating the jack.