JPH0517914A - Preventing device for falling of bridge used as damper in common - Google Patents

Abstract

PURPOSE:To reduce the response of a bridge in the case of occurrence of an earthquake by providing the outer periphery of the end of a post protrusively provided from a lower structure in an upper structure with a hollow rubber member concentrically to the post at a space between them. CONSTITUTION:The tip of a round steel post 3 protrusively provided from a lower structure 1 is inserted into a cylindrical steel sleeve 4 buriedly fixed to the lower face of an upper structure 2. A fender type hollow rubber member 5 is provided at a fixed space to the post 3, and fixed to the inner peripheral wall of the steel sleeve 4 to form a preventing device for the falling of bridge used as a damper in common. A hysteresis curve of the above device has a part being constant in reaction force. Thus a bridge hardly suffers shock during earthquake, and its displacement can therefore be checked for preventing the bridge from falling, and its vibration can be reduced by the attenuation of hysteresis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a fall bridge prevention device.

[0002]

2. Description of the Related Art FIGS. 12 and 13 show a conventional bridge prevention device, which is a round steel support column d projecting from a cylindrical steel shell c fixed in the lower end of a substructure a to a superstructure b. On the outer periphery of
A hard elastic body e is attached to the inner peripheral wall of the steel shell c at a constant interval concentrically with the pillar d, and the pillar hits the hard elastic body at the time of a large earthquake to stop the displacement and prevent the bridge from falling. ing.

[0003]

In the above-mentioned conventional device, since the coefficient of restitution of the hard elastic body is large, a large impact force is generated when the support column collides during a large earthquake. Further, since the conventional device does not have a spring function or a damper function, a horizontal spring or a damper is additionally required.

The present invention has been proposed in view of the above problems of the prior art, and its object is to provide a bridge prevention device having a damper function for reducing the response of the bridge at the time of an earthquake. There is a point to do.

[0005]

In order to achieve the above-mentioned object, a damper-combined bridge prevention device according to the present invention is concentric with the pillar on the outer periphery of the pillar projecting from the substructure in the superstructure. Hollow rubber is arranged at regular intervals. According to the invention of claim 2, each of the hollow rubbers has a plurality of cylindrical hollow portions filled with a viscous fluid, and the hollow rubbers are arranged between the adjacent hollow portions or outside the hollow rubber and the hollow portion. And a conduit with an orifice is connected to the tank.

Further, the invention of claim 3 is the invention of claim 2, wherein a plurality of independent hollow hollow rubbers arranged concentrically with the support columns each have a space filled with a viscous fluid. It is made of rubber.

[0007]

According to the present invention, the elastic body is provided on the outer periphery of the end of the strut projecting from the substructure in the superstructure so as to be arranged concentrically with the strut and spaced from the conventional rubber. By using hollow rubber instead of the hard elastic body, the hysteresis curve diagram shown in FIG. 3 is obtained. Therefore, this hysteresis curve has a portion where the reaction force is constant, and the displacement can be stopped by a relatively small reaction force due to energy absorption, and hysteresis damping can be expected. If it still does not stop, it stops at the hardening part to prevent the bridge from falling and it is relatively easy to obtain the cushioning material having the desired hysteretic characteristics.

According to the second and third aspects of the present invention, between the hollow cylindrical hollow portions filled with the viscous fluid,
Alternatively, when a viscous fluid flows from the compressed cavity to an adjacent cavity or an external tank, a conduit with an orifice is installed between the cavity and the tank disposed outside the hollow rubber. A viscous resistance is generated by the effect of, and a damping effect is obtained. Further, this viscous resistance is set independently of the rubber material by changing the performance of the orifice, so that the damping constant can be arbitrarily determined without changing the elastic coefficient so much.

[0009]

1 and 2 show a first embodiment of the present invention, in which 1 is a substructure, 2 is a superstructure, and the tip of a round steel column 3 protruding from the substructure 1 is The cylindrical steel shell 4 is embedded and fixed on the lower surface of the superstructure 2, and is projected into the cylindrical steel shell 4. Thus, a fender-type hollow rubber 5 is arranged at a predetermined distance from the pillar 3, and is fixed to the inner peripheral wall of the steel shell 4. In the figure, 6 is a rubber pad.

Since the illustrated embodiment is constructed as described above, its history curve is as shown in FIG. 3, and there is a portion where the reaction force is constant as described above, and a relatively small reaction force due to energy absorption. Displacement can be stopped without much impact and vibration can be reduced by hysteresis damping. 4 and 5 show a second embodiment of the present invention, in which a horizontal spring 7 made of rubber or the like is arranged on the upper part of the support column 3, one end of the spring 7 is mounted on the support column 3, and the other end is mounted on the steel shell 4. Mounted. In the figure, the same parts as those in the above embodiment are designated by the same reference numerals.

FIGS. 6 and 7 show a third embodiment of the present invention in which a viscous fluid 8 is used instead of the fender type hollow rubber.
A hollow rubber 5 is used in which a plurality of cylindrical cavities 5a filled with are arranged concentrically with the support column 3, and adjacent cavities 5a are connected by a conduit tube 9 with an orifice. Since the illustrated embodiment is configured as described above, when viscous fluid flows from the compressed cylindrical hollow portion 5a to the adjacent cylindrical hollow portion 5a during an earthquake or the like, viscous resistance is generated by the orifice. A damping effect is obtained. Further, this viscous resistance can be set independently of the rubber material by changing the performance of the orifice, so that the damping constant can be arbitrarily determined without changing the elastic coefficient so much.

FIG. 8 and FIG. 9 show a fourth embodiment of the present invention, in which the hollow rubber 5 is concentrically formed with a cylindrical cavity 5a filled with a plurality of viscous fluids 8 as in the case of the third embodiment. A conduit pipe 9 with an orifice is connected between each of the hollow portions 5a and an external tank 10 arranged on the outer circumference of the steel shell 4.
The viscous fluid 8 in the hollow portion 5a is configured to escape to the tank 10. In the figure, the same parts as those in the above embodiment are designated by the same reference numerals.

FIG. 10 and FIG. 11 show a fifth embodiment of the present invention, in which hollow rubber 5 concentrically with the pillar 3 and independent from each other is provided.
The hollow rubber 5 is filled with a viscous fluid 8 and an external tank 10 is provided around the outer circumference of the steel shell 4.
A conduit tube 9 with an orifice is connected between the and. In the above embodiment, the viscous liquid 8 is pushed back into the hollow rubber 5 through the pressurizing connection port 11 of the tank 10 on the side that has been crushed by the displacement after the earthquake is completed, so that the superstructure 2 is not damaged before the earthquake. A function for returning to the state can be added.

[0014]

As described above, according to the damper / falling bridge prevention device of the present invention, the hollow rubber is arranged in the upper work at a space concentric with the pillar projecting from the lower work. Displacement can be stopped without receiving much impact in the event of an earthquake or the like, a bridge can be prevented, vibration can be reduced by hysteresis damping, and necessary hysteresis characteristics can be set relatively easily.

Further, by installing a spring of rubber or the like, the horizontal spring is also used, and the damping effect can be further enhanced. According to the invention of claim 2, a plurality of cylindrical cavities provided in the hollow rubber are filled with the viscous liquid, and the viscous liquid is filled between adjacent cavities, or between the cavities and a tank disposed outside the hollow rubber. By connecting the conducting tube with an orifice in between, vibration is reduced by viscous damping caused by the orifice provided in the conducting tube, and the damping constant can be set independently of the elastic coefficient of rubber.

According to a third aspect of the present invention, concentric with the pillar,
By disposing a plurality of independent hollow rubbers each having a space filled with a viscous fluid inside, it is possible to have a function of returning the superstructure to the state before the earthquake.

[Brief description of drawings]

FIG. 1 is a first embodiment of a damper combined bridge prevention device according to the present invention.
It is a longitudinal section showing an example.

2 is a cross-sectional plan view of FIG.

FIG. 3 is a history curve diagram of the combined bridge prevention device for the damper.

FIG. 4 is a vertical sectional view showing a second embodiment of the present invention.

5 is a cross-sectional plan view of FIG.

FIG. 6 is a vertical sectional view showing a third embodiment of the present invention.

7 is a cross-sectional plan view of FIG.

FIG. 8 is a vertical sectional view showing a fourth embodiment of the present invention.

9 is a cross-sectional plan view of FIG.

FIG. 10 is a vertical sectional view showing a fifth embodiment of the present invention.

11 is a cross-sectional plan view of FIG.

FIG. 12 is a vertical cross-sectional view of a conventional bridge prevention device.

13 is a cross-sectional plan view of FIG.

[Explanation of symbols]

1 substructure 2 superstructure 3 props 4 steel shell 5 hollow rubber 5a Cylindrical cavity 6 rubber pad 7 Horizontal spring 8 Viscoelasticity 9 Conductive tube with orifice 10 tanks

Claims (3)

[Claims] 1. A damper-combined bridge, wherein hollow rubber is arranged on the outer circumference of the end of a pillar projecting from a substructure in the superstructure, with a concentric space between the pillar and the pillar. Prevention device. 2. The hollow rubber has a plurality of cylindrical hollow portions each filled with a viscous fluid, and a tank disposed between adjacent hollow portions or outside the hollow rubber and the hollow portions. The device for preventing collapse of a bridge also as a damper according to claim 1, wherein a conduit with an orifice is connected between them. 3. The damper-combined falling bridge according to claim 2, wherein the hollow rubber arranged concentrically with the pillar is composed of a plurality of independent hollow rubbers each having a space filled with a viscous fluid. Prevention device.