JP6767183B2 - Seismic structures and methods for improving seismic resistance - Google Patents

Description

The present invention relates to seismic structures and methods for improving seismic resistance, and more particularly to seismic structures and methods for improving seismic resistance that are applicable to piers that support bridge girders.

As shown in FIG. 4, the river bridge or the like is composed of a bridge girder 2, a bridge 3 (3A, 3B) and a pier 4 supporting the bridge girder 2, and movable bearings 5A and 5C are provided between the bridge girder 2 and the pier 3. There are many structures that are arranged and a fixed bearing 5B is provided between the bridge girder 2 and the pier 4. Such bridge 2 1 In order to ensure the earthquake resistance, it is necessary to apply the seismic reinforcement abutment 3 and pier 4, for example, in the river bridge, increasing the cross-sectional shape of the piers 4 from constraints Kawaseki inhibition rate In some cases, it was difficult to seismically reinforce the pier 4 due to problems such as the inability to do so and the possibility that the construction period would be limited and the construction would be complicated because the bridge pier 4 was installed in the river. In addition, there was a similar problem with sabo river bridges and mountain bridges.

Therefore, as in the bridge 31 shown in FIG. 5, it is conceivable to replace the movable bearings 5A and 5C and the fixed bearings 5B shown in FIG. 4 with seismic isolation bearings 6 such as laminated rubber to satisfy the seismic resistance.

However, since the abutment 3 shown in FIG. 5 receives a larger earth pressure on the back soil side, the seismic resistance is not easily impaired by the inertial force (passive earth pressure direction) from the front surface of the abutment 3, but the back soil. Since the earth pressure cannot be received against the inertial force from the side (in the direction of the main earth pressure), there is a concern that the earthquake resistance will be impaired. In the bridge 31 shown in FIG. 5, in the event of an earthquake or the like, as shown in FIG. 6, the seismic isolation bearings 6 (6A, 6B) installed on the abutment 3 are in either the starting point side or the ending point side (either left or right). Since it also deforms in the direction), the inertial force is also transmitted in the driving soil pressure direction (right direction for the pier 3A, left direction for the pier 3B), and there is a risk that the seismic resistance of the pier 3 cannot be satisfied. ..

Therefore, the present invention has been made in view of the problems in the seismic structure of the existing bridge, etc., so that the inertial force acting in the direction of the driving soil pressure acting on the pier in the event of an earthquake or the like is minimized. It is an object of the present invention to provide a seismic structure and a method for improving seismic resistance, which is easy to construct and has excellent economic efficiency, without reinforcing piers and abutments as much as possible.

In order to achieve the above objectives, in the past, when the support structure was installed, the stress acting on the support structure in the direction of the main earth pressure and the stress in the direction of the passive earth pressure were balanced. The seismic structure according to the present invention includes an upper structure and the above structure so that the stress applied to the support structure on the passive earth pressure direction side becomes larger than the stress on the main earth pressure direction side when the support structure is installed. It is characterized in that an elastic support or an elastic device that has been elastically deformed in advance on the passive earth pressure direction side of the support structure is provided between the support structure that receives the earth pressure while supporting the structure. As the elastic bearing or the elastic device, a bearing or a damper capable of applying an elastic force conventionally used can be used.

According to the present invention, the elastic bearing or the elastic device is elastically deformed in the passive soil pressure direction side of the support structure in advance, so that the force applied to the support structure in the main soil pressure direction at the time of an earthquake can be suppressed to a small extent. Since the force in the passive soil pressure direction, which has a large load bearing capacity, can be increased, the cross-sectional shape of the support structure can be increased, and the seismic resistance can be improved without separately performing seismic reinforcement. However, even in the case of an existing bearing, it can be used as it is by simply replacing or attaching it to an elastic bearing or an elastic device, so that the construction is easy and the economy is excellent.

In the seismic structure, the support structure can be a pier that supports a bridge, a dam, or a bridge girder of a movable weir. Further, the elastic bearing may be a laminated rubber bearing having no damping performance or a seismic isolation bearing having damping performance, or the elastic device may be a cylinder, a rod arranged in the cylinder, the cylinder and a rod. It may be provided with an elastic body interposed between the and, and may have or have no damping performance. Further, a rubber bearing with a lead plug or a high damping rubber bearing can be used for the seismic isolation bearing, and a laminated rubber, a seismic isolation rubber, a coil spring or the like can be used for the elastic body of the elastic device. ..

Further, the present invention is a method for improving earthquake resistance, in which a support structure that receives soil pressure while supporting the upper structure is provided, and elastic support or elasticity is provided between the upper structure and the support structure. An apparatus is interposed, and the elastic support or the elastic device is elastically deformed in advance toward the passive soil pressure direction of the support structure.

According to the present invention, the elastic support or the elastic device is elastically deformed in the passive earth pressure direction side of the support structure in advance, so that the force applied to the support structure in the main earth pressure direction at the time of an earthquake can be suppressed to a small extent. Since the force in the passive earth pressure direction, which has a large load bearing capacity, can be increased, the cross-sectional shape of the support structure can be increased, and the seismic resistance can be improved without separately performing seismic reinforcement. However, even if it already exists, it can be used as it is by simply replacing or attaching it to an elastic support or an elastic device, so that construction is easy and it is excellent in economy.

In the seismic resistance improving method, the support structure may be a pier that supports a bridge, a dam, or a bridge girder of a movable weir. Further, the elastic bearing may be a laminated rubber bearing having no damping performance or a seismic isolation bearing having damping performance, or the elastic device may be a cylinder, a rod arranged in the cylinder, the cylinder and a rod. It may be provided with an elastic body interposed between the and, and may have or have no damping performance. Further, a rubber bearing with a lead plug or a high damping rubber bearing can be used for the seismic isolation bearing, and a laminated rubber, a seismic isolation rubber, a coil spring or the like can be used for the elastic body of the elastic device. ..

As described above, according to the present invention, it is possible to provide a seismic structure that is easy to construct and has excellent economic efficiency and a method for improving seismic resistance without reinforcing support structures such as piers and abutments as much as possible. it can.

It is a schematic diagram which shows the seismic structure which concerns on this invention, and the bridge which applied the seismic resistance improvement method. It is the schematic for demonstrating the operation of the bridge of FIG. It is a figure which shows an example of the elastic apparatus used for the seismic structure which concerns on this invention, (a) is a vertical sectional view, (b) is a sectional view taken along line AA of (a). It is a schematic diagram which shows an example of an existing bridge. It is a schematic diagram which shows another example of an existing bridge. It is the schematic which shows the state after the abutment and a pier shown in FIG. 5 are horizontally displaced.

Next, a mode for carrying out the present invention will be described in detail with reference to the drawings. In the following description, a case where the seismic structure according to the present invention is used for an abutment such as a river bridge will be illustrated.

FIG. 1 shows an embodiment of a bridge having a seismic structure (pier) according to the present invention, in which the bridge 1 has a bridge girder 2 and a bridge girder similar to the existing bridges 31 shown in FIGS. 5 and 6. A bridge 3 (3A, 3B) and a pier 4 for supporting 2 are provided, and a laminated rubber bearing 7 (7A to 7C) is further provided.

Laminated rubber bearings 7 (7A to 7C) are generally used. For example, rubber and steel plates are laminated and vulcanized and bonded to increase the rigidity in the vertical direction and decrease the rigidity in the horizontal direction. It is a thing. The laminated rubber bearings 7A and 7B are installed on the abutments 3A and 3B in a state of being shear-deformed in advance in the passive earth pressure direction of the abutments 3A and 3B, and are installed on the pier 4 without applying shear deformation. The passive earth pressure direction is the left direction at the pier 3A and the right direction at the pier 3B. The laminated rubber bearings 7A and 7B may be shear-deformed before being installed on the abutments 3A and 3B, and the laminated rubber bearings 7A and 7B may be shear-deformed after being installed on the abutments 3A and 3B.

In the bridge 1 having the above configuration, the laminated rubber bearings 7A and 7B are shear-deformed in advance in the passive earth pressure direction of the abutments 3A and 3B, so that a force in the passive earth pressure direction is normally applied to the abutments 3A and 3B. It is balanced in a state of being. Then, in the event of an earthquake or the like, for example, even if the abutment 3 and the pier 4 move relative to the left with respect to the bridge girder 2, the inertial force in the main earth pressure direction does not increase for the abutment 3A, and the abutment 3B Since it is possible to bear a large inertial force in the passive earth pressure direction, the seismic resistance of the pier 3 can be satisfied.

As described above, due to the preliminary shear deformation of the laminated rubber bearing 7, the abutment 3 is hung on the abutment 3 by utilizing the characteristic that the abutment 3 is weak against the force in the main earth pressure direction and strong against the force in the passive earth pressure direction. Since the force in the main earth pressure direction can be suppressed to a small value and the force in the passive earth pressure direction can be increased accordingly, the cross-sectional shape of the abutment 3 and the pier 4 can be increased, and the seismic resistance is improved without separately performing seismic reinforcement. Can be made to. Further, even when the bridge 1 already exists, the bridge pedestal 3 and the pier 4 can be used as they are by simply replacing the bridge 1 with the laminated rubber bearing 7.

In addition, instead of the laminated rubber bearing 7, a seismic isolation bearing having damping performance is used, and the same effect can be obtained by imparting the above-mentioned preliminary elastic deformation.

Further, instead of the laminated rubber bearing 7, the following elastic device can be used.

As shown in FIG. 3, the elastic device 11 is arranged between the bridge girder 2 and the abutment 3A in the horizontal direction, and one end is fixed to the abutment 3A and one end is fixed to the bridge girder 2. It is composed of a tubular member 13 and a tubular elastic body 14 whose inner peripheral surface is fixed to the outer peripheral surface of the long member 12 and whose outer peripheral surface is fixed to the inner peripheral surface of the tubular member 13 in the passive earth pressure direction (passive earth pressure direction). It is elastically deformed to the right) side in FIG. 3A. The tubular member 13 may be either a cylinder or a square cylinder. The elastic body 14 is composed of a rubber 14a and a plurality of concentric cylindrical steel plates 14b.

On the other hand, although not shown, the other abutment 3B is also provided with an elastic device 11 having the above configuration, and the elastic body 14 of the abutment 3B is also elastically deformed in the passive earth pressure direction side in advance. Further, the pier 4 is provided with the laminated rubber bearing 7C shown in FIG. 1 without applying shear deformation, and the pier 3 (3A, 3B) and the pier 4 support the bridge girder 2. The elastic body 14 of the elastic device 11 can be shear-deformed before or after being installed on the abutments 3A and 3B.

Even in a bridge having the above configuration, even if the abutment 3 and the pier 4 move relative to the left with respect to the bridge girder 2 in the event of an earthquake or the like, the abutment 3A to which the elastic device 11 is arranged has the main earth pressure. Since the force in the direction (rightward in FIG. 3A) does not increase and a large inertial force can be applied in the passive earth pressure direction, the seismic resistance of the pier 3A can be satisfied. Further, a force acts on the abutment 3B in the same manner, and the seismic resistance of the abutment 3B can be satisfied.

Further, although not shown, one of the abutments 3B may be a fixed bearing without the elastic device 11. In this case, normally, the fixed bearing of the pier 3B receives the pressing force from the elastic device 11 of the pier 3A via the bridge girder 2, and the fixed bearing of the pier 3B is balanced with the force in the passive earth pressure direction applied. Therefore, the situation is almost the same as the basic configuration shown in FIG. 1, and the earthquake resistance of the piers 3A and 3B can be satisfied.

It should be noted that the elastic device 11 to which the preliminary elastic deformation is applied as described above is not installed in place of the laminated rubber bearing 7, but the bridge 31 having the existing bearings 6 (6A to 6C) shown in FIG. The same effect can be obtained even if it is installed between the bridge girder 2 and the bridge stands 3A and 3B.

Further, instead of the elastic device 11, different types of elastic devices can be used, and elastic devices having damping performance and elastic devices having independent configurations can be installed in combination.

Further, as the installation target of the elastic bearing and the elastic device, in addition to the pier of the bridge, the pier of the bridge girder of the dam or the movable weir can be mentioned.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments described above, and various modifications and applications are possible without departing from the gist of the present invention. ..

1 Bridge 2 Bridge girder 3 (3A, 3B) Abutment 4 Pier 7 (7A-7C) Laminated rubber bearing 11 Elastic device 12 Long member 13 Cylinder member 14 Elastic body 14a Rubber 14b Steel plate

Claims (12)

A support structure that receives earth pressure while supporting the upper structure,
The passive soil pressure of the support structure between the upper structure and the support structure so that the stress on the passive soil pressure direction side of the support structure is larger than the stress on the main driving soil pressure direction side. A seismic structure characterized by providing an elastic support or an elastic device elastically deformed in advance on the directional side. The seismic structure according to claim 1, wherein the support structure is a pier that supports a bridge, a dam, or a bridge girder of a movable weir. The seismic structure according to claim 1 or 2, wherein the elastic bearing is a laminated rubber bearing having no damping performance. The seismic structure according to claim 1 or 2, wherein the elastic bearing is a seismic isolation bearing having damping performance. The elastic device includes a cylinder, a rod arranged in the cylinder, and an elastic body interposed between the cylinder and the rod, and has no damping performance. Seismic structures described in. The elastic device according to claim 1 or 2, further comprising a cylinder, a rod arranged in the cylinder, and an elastic body interposed between the cylinder and the rod, and having a damping performance. Seismic structure. A support structure that receives earth pressure while supporting the upper structure is provided.
An elastic support or an elastic device is interposed between the upper structure and the support structure so that the stress on the passive earth pressure direction received by the support structure is larger than the stress on the main earth pressure direction. A method for improving earthquake resistance, which comprises elastically deforming the elastic support or elastic device in the passive earth pressure direction side of the support structure in advance. The seismic resistance improving method according to claim 7, wherein the support structure is a pier that supports a bridge, a dam, or a bridge girder of a movable weir. The method for improving seismic resistance according to claim 7 or 8, wherein the elastic bearing is a laminated rubber bearing having no damping performance. The method for improving seismic resistance according to claim 7 or 8, wherein the elastic bearing is a seismic isolation bearing having damping performance. Claim 7 or 8 is characterized in that the elastic device includes a cylinder, a rod arranged in the cylinder, and an elastic body interposed between the cylinder and the rod, and does not have damping performance. Seismic resistance improvement method described in. The 7 or 8 claim, wherein the elastic device includes a cylinder, a rod arranged in the cylinder, and an elastic body interposed between the cylinder and the rod, and has damping performance. How to improve earthquake resistance.

Images