JP3842399B2 - Girder fall prevention device for bridge - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for preventing a girder from falling from a pier due to an earthquake in a bridge.
[0002]
[Prior art]
As a structure to prevent bridge girders from dropping on highways and railways due to earthquake vibration, before the Hyogoken-Nanbu Earthquake, girders are connected with a technology using a reinforcing plate and metal pins, or with a chain or cable. There was a technology to connect between them.
[0003]
[Problems to be solved by the invention]
However, the conventional technology was installed to prevent the girder from falling over the girder hanging part on the top of the pier where the girder is placed. Was completely blocked, which became a major obstacle to the subsequent recovery activities.
[0004]
Also, if the cause of the phenomenon of girder dropping due to an earthquake is assumed to be seismic force and seismic energy, a buffer material for mitigating the generated seismic force is effective against the seismic force. The technology of the buffer pin which utilized the damper function of rubber and the buffer pin which covered the outer periphery of the pin with rubber has been developed, and its performance has been proved and put into practical use by the impact test using the connecting part and the connecting part.
[0005]
On the other hand, a member capable of absorbing as much energy as possible against earthquake energy is effective. Therefore, a material in which a fibrous body is laminated and embedded in rubber is provided as a buffer material for the above-mentioned buffer chain or pin. Laminates have been proposed that use and increase the total amount of absorbed energy by breaking the fibrous body.
However, since the seismic energy is enormous, these cushioning materials and laminates have insufficient energy absorption, and it is considered that the girders move over the girder and fall.
[0006]
[Means for Solving the Problems]
In view of the above, the present invention provides an elastic buffer body having a substantially triangular plate-like cross-sectional shape to a girder part where a girder is attached to a girder part on the upper surface of the pier via a support body. It is characterized in that it is arranged in at least one row so that the inclined surface faces the support body in the bridge axis direction and the direction orthogonal thereto, and further, the fibrous body is laminated inside the buffer body.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
First Embodiment FIG. 1 is a plan view, FIGS. 2 to 5 are explanatory views showing an operating state, FIG. 6 is a sectional view of a shock absorber, and in the figure, 1 is a girder on the upper surface of the pier, 2 is Girder 3 is a support for supporting girder 2 to girder 1 and generally elastic body 4 such as rubber or synthetic resin is attached to girder 2 and girder 1 by means of bolts or the like via iron plate 5. It is stuck. Therefore, the girder 2 is placed and fixed to the girder hanging portion 1 via the support body 3.
[0008]
Reference numeral 6 denotes a buffer, which is made of a plate-like elastic body having a substantially triangular cross-sectional shape. In the elastic body 7 such as rubber or synthetic resin, a woven fabric or a non-woven fabric made of natural fibers, synthetic fibers, or the like, or metal. The fiber body 8 made of a net or the like is laminated and embedded so as to be fully integrated, and a rigid body 9 such as an iron plate is embedded in the lower part as necessary.
Note that the cross-sectional shape is a substantially triangular shape having the inclined surface 10 as described above, and may be a shape in which a flat portion 11 is formed at the upper end as shown in FIGS. 7 and 8, and the inclined surface 10 is concave or The surface may be curved convexly, and the surface may be not a smooth surface but a non-slip surface such as a stepped shape. Further, the upper surface may be covered with a rigid body such as an iron plate.
[0009]
The above-described fiber body 8 may be laminated in any direction such as a state parallel to the bottom surface, a state parallel to the surface, or a state perpendicular to the bottom surface. Furthermore, in the structure of a light beam such as a pedestrian bridge, a structure of a single elastic body without the fiber body 8 may be used.
The buffer body 6 may be fixed to the girder 1 by using a fixing tool such as a bolt. Further, as shown in FIG. Any fixing structure such as a structure in which the engaging recess is fitted and locked to the locking recess may be used.
[0010]
As shown in FIG. 1, the buffer body 6 configured as described above is arranged in a line or a plurality of lines so that the inclined surface faces the support body 3 in the bridge axis direction of the girder 1 around the support body 3 and in the direction orthogonal thereto. Between the support body 3 and the buffer body 6 and between the buffer body 6 and the buffer body 6, a buffer plate 13 in which a fiber body is laminated and embedded in an elastic body is provided as necessary in the same manner as the structure of the buffer body 6. If placed, there is a buffering effect. Of course, the buffer bodies 6 may be continuously arranged without the buffer plate 13 interposed.
[0011]
As described above, when the buffer body 6 is arranged around the support body 3 of the girder hanging portion 1, when the earthquake occurs and the support body 3 is sheared and broken, the girder 2 is placed on the buffer plate 13 as shown in FIG. Alternatively, if the girder 2 falls on the shock absorber 6 and further moves due to the aftershock, it moves with the inclined surface of the shock absorber 6 facing upward and destroys the internal fiber body 8, and the movement is still promoted. In this case, the girder 2 falls on the next buffer plate 13 or the buffer body 6 as shown in FIG.
[0012]
Energy absorption in this case is (1) elastic strain energy of the buffer body (6), (2) breaking energy of the fiber body (8), and (3) potential energy falling from the buffer body. As shown in FIG. 9, the present invention is characterized in that this energy attenuation is high, and the falling potential energy is a huge energy attenuation represented by Eh = W · h.
[0013]
By the attenuation of these energies, it is possible to prevent the girder that the support body 3 has sheared and broken from falling from the pier.
Therefore, arranging the buffer bodies 6 continuously has a large energy attenuation effect, and the possibility that the girder falls from the girder portion on the upper surface of the pier is reduced. However, there is a structural limitation in enlarging the girder part, and the installation amount of the buffer body 6 depends on the size of the girder part and the size of the buffer body 6 depending on the inclination angle and height of the inclined surface of the buffer body 6. It depends on.
[0014]
Although not related to the configuration of the present invention, the safety of the girder dropping is further enhanced if a locking portion made of a rigid body such as concrete is formed around the girder hanging portion.
Second Embodiment In this embodiment, as shown in FIG. 10, the buffer plate 13 is formed integrally with the buffer body 6, and the length of the buffer plate 13 is the inclination angle of the inclined surface of the buffer body 6. It depends on the size of the buffer body 6 depending on the height.
[0015]
Third Embodiment In this embodiment, a buffer body 6 is formed so as to surround the support body 3 of the girder part. The buffer body 6 is formed in a square shape as shown in FIG. 11 or in a circular shape as shown in FIG. Any shape may be used.
According to such a configuration, it is possible to cope with any direction and the attachment work is facilitated.
[0016]
【The invention's effect】
According to the present invention described in detail above, a shock absorber made of a plate-like elastic body having a substantially triangular cross-section in a girder part where a girder is attached to a girder part on the upper surface of a pier via a support body, When the girder moves due to the occurrence of an earthquake and shear breakage of the support body by arranging one or more rows so that the inclined surface faces the support body in the bridge axis direction and the direction perpendicular to it The girder end moves with the inclined surface of the shock absorber facing upward while attenuating the earthquake energy due to the elastic strain energy of the shock absorber. By attenuating, it has the effect of preventing the girder from falling off the pier.
[0017]
Furthermore, in the structure in which the fibrous body is laminated inside the buffer body, the seismic energy can be further attenuated by the breaking energy of the fibrous body, and an effect that a further attenuation effect can be expected.
[Brief description of the drawings]
FIG. 1 is a plan view showing a first embodiment. FIG. 2 is an explanatory diagram showing an operating state. FIG. 3 is an explanatory diagram showing an operating state. FIG. 4 is an explanatory diagram showing an operating state. FIG. 6 is a cross-sectional view of a shock absorber. FIG. 7 is a cross-sectional view of another shock absorber. FIG. 8 is a cross-sectional view of another shock absorber. FIG. 9 is a graph showing energy attenuation. FIG. 11 is a plan view of a buffer body showing a third embodiment. FIG. 12 is a plan view of a buffer body showing a third embodiment. Explanation of]
DESCRIPTION OF SYMBOLS 1 Girder part 2 Girder 3 Support body 6 Buffer body 7 Elastic body 8 Fiber body 9 Rigid body 10 Inclined surface 11 Flat part 12 Locking part 13 Buffer plate

Claims (5)

In the girder part where the girder is attached to the girder part on the upper surface of the pier via a support body, a shock absorber made of an elastic body having a substantially triangular cross-sectional shape, the axial direction of the bridge around the support body and the same A girder drop prevention device for a bridge, wherein the girder drop prevention device is arranged in at least one row so that an inclined surface faces a support body in a direction perpendicular to the bearing. The girder drop prevention device according to claim 1, wherein a fibrous body is laminated inside the buffer body. The girder fall prevention device for a bridge according to claim 1, wherein a buffer plate is disposed at a front portion of the buffer body on the support body side. 2. The girder falling prevention device for a bridge according to claim 1, wherein a buffer body is arranged so as to surround the support body of the girder hanging portion. The girder drop prevention device according to claim 1, wherein the upper surface of the buffer body is covered with a rigid plate.

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