JP5266681B2 - Seismic isolation method for bridges and bridges - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bridge which enables a person, a vehicle, etc. to easily and stably stop on a bridge girder in either of the case of the occurrence of a big earthquake and the ordinary case of the nonoccurrence of the big earthquake, and a base-isolating method for the bridge. <P>SOLUTION: This bridge 1 comprises a bridge pier supporting member 40 which is installed on a footing 30 fixed to ground G so as to support a bridge pier 20 in a horizontally and relatively movable manner, and a bridge girder supporting member 60 which is provided on the bridge pier 20 so as to support the bridge girder 10 in a horizontally and relatively movable manner. Until the bridge girder supporting member 60 undergoes an earthquake motion at a predetermined level or above, it allows the relative displacement of the bridge girder 10 with respect to the bridge pier 20. Until the bridge pier supporting member 40 undergoes the earthquake motion at the predetermined level or above, it regulates the relative displacement of the bridge pier 20 with respect to the footing 30. When and after the bridge girder supporting member 60 undergoes the earthquake motion at the predetermined level or above, it regulates the relative displacement of the bridge girder 10 with respect to the bridge pier 20. When and after the bridge pier supporting member 40 undergoes the earthquake motion at the predetermined level or above, it allows the relative displacement of the bridge pier 20 with respect to the footing 30. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a bridge and a seismic isolation method for the bridge.

Seismic isolation devices are widely used to protect buildings and ordinary houses from earthquakes. Recently, application to a bridge has also been studied. For example, in Patent Document 1, a seismic isolation device is interposed between a footing fixed to the ground and a bridge pier, and the horizontal direction between the footing and the pier is determined. The bridge which enabled the relative movement is disclosed (refer patent document 1).
JP 2004-293157 A

  On the other hand, other bridges have been studied in which a seismic isolation device is interposed between the bridge girder and the pier, and the bridge girder and the pier can be relatively moved in the horizontal direction.

  However, in the former bridge of Patent Document 1, since a seismic isolation device is not interposed between the bridge girder and the pier, the bridge girder and the pier are substantially integrated. Therefore, the bridge girder substantially vibrates horizontally not only by the wind hitting the bridge girder but also by the wind hitting the pier, that is, the frequency of occurrence of horizontal vibration of the bridge girder during normal time increases.

  In the latter bridge, the bridge girder is isolated but the pier is not isolated, so there is a risk of damage to the pier when a large earthquake occurs.

  Therefore, both of these two types of seismic isolation devices are provided, that is, both between the footing 30 and the pier 20 and between the pier 20 and the bridge girder 10 as shown in the side view of the bridge 1a in FIG. It can be considered that the seismic isolation devices 40a and 60a are provided in the base, and if this is done, it is possible to avoid the problem of increasing the frequency of occurrence of horizontal vibration of the bridge girder 10 and the problem of damage to the pier 20 during a large earthquake.

  However, in the case where the two types of seismic isolation devices 40a and 60a are provided side by side, both the bridge girder 10 and the pier 20 are horizontally vibrated by the seismic isolation device 40a and the seismic isolation device 60a, respectively. In addition to the relative vibration of the bridge girder 10 with respect to the pier 20, the relative vibration of the pier 20 with respect to the footing 30 is also superimposed on 10. That is, the substantial maximum amplitude of the bridge girder 10 is the sum of the maximum amplitude of the bridge girder 10 with respect to the pier 20 and the maximum amplitude of the pier 20 with respect to the footing 30. Therefore, the bridge girder 10 may vibrate with a large amplitude due to wind or the like even during normal times, and it may be difficult for a person or a vehicle to pass over the bridge girder 10 or even to stay there.

  On the other hand, when earthquake motion is input to the bridge 1a when a large earthquake occurs, the bridge 1a vibrates in units of the bridge girder 10, that is, the mass of vibration is only the bridge girder 10 and its inertial mass is small. The bridge girder 10 vibrates in a short cycle, and in the worst case, the bridge girder may drop off from the pier. As a result, people and vehicles that have encountered a large earthquake on the bridge girder 10 It will be difficult to stay on top of 10 stably.

  The present invention has been made in view of such conventional problems. Bridges and bridge exemptions are easy for people, vehicles, etc. to stay stably on bridge girders both in the event of a major earthquake and in the absence of a major earthquake. The purpose is to provide a seismic method.

In order to achieve this object, the invention shown in claim 1
A bridge pier support member provided on a footing fixed to the ground and supporting the pier in a horizontal direction so as to be relatively movable; and a bridge girder support member provided on the pier and supporting the bridge girder in a horizontal direction so as to be relatively movable. A bridge,
The bridge girder support member allows relative movement of the bridge girder with respect to the pier, and the pier support member regulates relative movement of the pier with respect to the footing until it receives earthquake motion of a predetermined level or more.
The bridge girder support member restricts the relative movement of the bridge girder with respect to the pier, and the pier support member allows the relative movement of the pier with respect to the footing after receiving the earthquake motion of the predetermined level or more. Features.

  According to the first aspect of the present invention, it is easy for people, vehicles, and the like to stay stably on the bridge girder both in the event of a major earthquake and in the normal time without a major earthquake.

  Details are as follows. The bridge girder moves relative to the pier, but the pier does not move relative to the footing until seismic motion above a predetermined level. Therefore, in normal times, the bridge pier does not vibrate, and only the bridge girder vibrates. In other words, the maximum amplitude of vibration of the bridge girder supported by the pier is reduced by the amount that the pier does not vibrate, and as a result, vibration of the bridge girder is suppressed during normal times, and people and vehicles are likely to remain stable on the bridge girder. Become.

  On the other hand, the bridge pier moves relative to the footing after receiving earthquake motion of a predetermined level or more, but the bridge girder does not move relative to the pier. Therefore, during and after the occurrence of a major earthquake, the bridge girder and pier are connected and integrated to behave as if they were one large mass point and vibrate. Also, dropping of the bridge girder from the pier is effectively prevented. As a result, it becomes easy for people and vehicles to stay stably on the bridge girder.

The invention according to claim 2 is the bridge according to claim 1,
A plurality of the piers are arranged along the girder length direction of the bridge girder, and a pair of the piers adjacent to each other in the girder length direction are sequentially supported by the corresponding bridge girder.
After receiving the earthquake motion of the predetermined level or more, the relative movement of the bridge girder with respect to the pier is restricted for all bridge girder.

  According to the second aspect of the present invention, after receiving the earthquake motion of the predetermined level or higher, all bridge girders of the bridge are restricted from moving relative to the pier, that is, all the bridge girders are fixed to the pier. All bridge piers are connected and integrated through each bridge girder. Therefore, the bridges vibrate because all these bridge girders and piers behave as if they were connected and integrated, and as a result, it is possible to maximize the vibration of the bridge girders.

The invention shown in claim 3
A bridge pier support member provided on a footing fixed to the ground and supporting the pier in a horizontal direction so as to be relatively movable; and a bridge girder support member provided on the pier and supporting the bridge girder in a horizontal direction so as to be relatively movable. A seismic isolation method for the bridge
The bridge girder support member allows relative movement of the bridge girder with respect to the pier, and the pier support member regulates relative movement of the pier with respect to the footing until it receives earthquake motion of a predetermined level or more.
The bridge girder support member restricts the relative movement of the bridge girder with respect to the pier, and the pier support member allows the relative movement of the pier with respect to the footing after receiving the earthquake motion of the predetermined level or more. Seismic isolation method for the bridge.

  According to the third aspect of the present invention, the same effect as that of the first aspect can be obtained.

  According to the bridge and the bridge seismic isolation method of the present invention, it is easy for people, vehicles, and the like to stay on the bridge girder stably both in the event of a large earthquake and in the normal time without a large earthquake.

=== Seismic isolation method for bridge 1 and bridge 1 according to the present embodiment ===
<<< Overall configuration of Bridge 1 >>>
FIG. 2 is a side view of the bridge 1 according to the present embodiment. This bridge 1 is a continuous viaduct. That is, a plurality of bridge piers 20 are arranged side by side along the girder length direction of the bridge girder 10, and the corresponding bridge girder 10 is bridged between the bridge piers 20, 20 adjacent to each other in the girder length direction. Thus, one viaduct 1 in which a plurality of bridge girders 10 are connected in the girder length direction is formed.

  Each bridge pier 20 is supported by a footing 30 in the ground G via a horizontal pier base isolation device 40. Pile 32 is integrally provided at the lower part of each footing 30, and these footing 30 and pile 32 function as the foundation of bridge 1. The pier 20 and the footing 30 are made of concrete such as RC (steel reinforced concrete) or SRC (steel reinforced concrete), respectively, and the pile 32 is made of prestressed concrete or steel. The bridge pier horizontal seismic isolation device 40 is a support member for supporting the pier 20 so as to be relatively movable in the horizontal direction with respect to the footing 30, whereby the pier 20 is horizontally isolated. The pier horizontal seismic isolation device 40 will be described later.

  Each bridge girder 10 is supported at both ends via the bridge girder horizontal seismic isolation device 60 on the upper surface of the piers 20 and 20 adjacent to each other in the girder length direction. The bridge girder 10 is also made of concrete such as RC or SRC. The bridge girder horizontal seismic isolation device 60 is a support member that supports the corresponding ends 10a and 10b of the bridge girder 10 with respect to the pier 20 so as to be relatively movable in the horizontal direction, and is provided for each of the ends 10a and 10b of the bridge girder 10. Thus, each bridge girder 10 is horizontally isolated. This bridge girder horizontal seismic isolation device 60 will also be described later.

<<< Horizontal seismic isolation device 40 for bridge piers >>>
3A to 3C are explanatory views of the horizontal pier seismic isolation device 40 for piers. 3A is a cross-sectional view of the pier 20, and FIGS. 3B and 3C are a BB cross-sectional view and a CC cross-sectional view, respectively, in FIG. 3A.

  The bridge pier horizontal seismic isolation device 40 is provided on the footing 30 and includes a sliding support member 42 that supports the pier 20 so as to be relatively movable in the horizontal direction. The main body 42 includes a return spring 46 and a first stopper. 50 and added.

  The sliding support member 42 includes a lower sliding plate 43 made of a Teflon plate fixed to the upper surface of the footing 30 and an upper sliding plate 44 made of a stainless steel plate fixed to the lower surface of the pier 20. The upper slidable plate 44 and the lower slidable plate 43 slide in the horizontal direction with their sliding surfaces in contact with each other, so that the pier 20 is supported so as to be movable relative to the footing 30 in the horizontal direction. .

  The restoring spring 46 is for restoring the pier 20 that has moved relative to the footing 30 in the horizontal direction. The restoring spring 60 is, for example, laminated rubber, and is provided across the pier 20 and the footing 30 on the side of the pier 20 to connect them.

  The first stopper 50 prevents the above-mentioned sliding support member 42 from functioning until it receives an earthquake motion of level 2 or higher. That is, the relative movement between the pier 20 and the footing 30 is restricted until a level 2 or higher earthquake motion is received, and after the level 2 or higher earthquake motion is received, the relative movement is allowed. By the way, level 2 ground motion here means “level 2 ground motion” as shown in “Road Bridge Specification (V Seismic Design) / Description” (Japan Road Association), etc. is there.

  As shown in FIG. 3C, the first stopper 50 having such a function includes a bracket 51 fixed to the side of the pier 20, and a bracket 52 fixed to the side of the footing 30 corresponding to the bracket 51. It has. The horizontal flanges 51a and 52a of the brackets 51 and 52 that are opposed to each other are formed with through holes for passing the shear pins 53 in the vertical direction, respectively. A retaining member 54, 54 such as a nut is provided to prevent the shear pin 53 from falling off.

  If such first stoppers 50 are installed in at least two places, the pier 20 and the footing 30 are restrained in a substantially completely non-relative state where not only translational movement but also rotational movement is impossible. Become. Therefore, in this example, the first stoppers 50 are provided at four locations around the pier 20 and the footing 30 as shown in FIG. 3A.

  Here, the shear strength of the shear pins 53 is set so as not to be broken by an earthquake motion of level 2 or less, but when the earthquake motion of level 2 is received, all four shear pins 53 are broken.

  Therefore, until the seismic motion of level 2 or higher is received, the shear pin 53 is not broken and the relative movement between the pier 20 and the footing 30 is restricted. On the other hand, after receiving the earthquake motion of level 2 or higher, the shear pin 53 is broken and the first stopper 50 does not function, and the sliding support member 42 functions accordingly, and the pier 20 and the footing 30 are Relative movement is allowed. That is, at the time of receiving a ground motion of level 2 or higher and after that, the pier 20 is cut so as to be relatively movable from the ground G on the footing 30 side, thereby suppressing the input of the ground motion of level 2 or higher to the pier 20. Thus, damage and collapse of the pier 20 are effectively prevented.

<<< Horizontal seismic isolation device 60 for bridge girders >>>
4A to 4C are explanatory views of the horizontal seismic isolation device 60 for bridge girders. 4A is a plan view of the pier 20 and the bridge girder 10, FIG. 4B is a side view thereof, and FIG. 4C is a cross-sectional view taken along the line CC in FIG. 4A.

  The horizontal seismic isolation device 60 for a bridge girder is provided on the pier 20 and includes as a main body a sliding support member 62 that supports the end portions 10a and 10b in the girder length direction of the bridge girder 10 so as to be relatively movable in the horizontal direction. 62, a restoring spring 66 and a second stopper 70 are additionally provided.

  The sliding support member 62 is made of a lower sliding plate 63 made of a Teflon plate fixed to the upper surface 20a of the pier 20 and a stainless steel plate fixed to the lower surface of each end portion 10a, 10b in the girder length direction of the bridge girder 10. And an upper sliding plate 64. The upper sliding plate 64 and the lower sliding plate 63 slide in the horizontal direction with their sliding surfaces in contact with each other, so that the end portions 10a and 10b of the bridge girder 10 are relative to the pier 20 in the horizontal direction. It is supported movably.

  The restoring spring 66 is used to restore the ends 10 a and 10 b of the bridge girder 10 that has moved relative to the pier 20 in the horizontal direction. The restoring spring 66 is, for example, laminated rubber, and is provided on the side of the bridge girder 10 so as to straddle the bridge girder 10 and the bridge pier 20 so as to connect them.

  The second stopper 70 is a device that prevents the sliding support member 62 from functioning after receiving an earthquake motion of level 2 or higher. That is, the relative movement between the end portions 10a and 10b of the bridge girder 10 and the pier 20 is allowed until an earthquake motion of level 2 or higher, but the relative movement is restricted after receiving the earthquake motion of level 2 or higher. .

  As shown in FIGS. 4A and 4B, the second stopper 70 having such a function is arranged on the upper side based on a seismic motion sensor (not shown) such as a three-dimensional displacement meter that detects seismic motion and a detection signal of the seismic motion sensor. A relative movement control mechanism 72 that controls the relative movement between the sliding plate 64 and the lower sliding plate 63 is provided.

  The relative movement control mechanism 72 is a clutch mechanism, for example, and has a pair of friction plates 73a and 73b facing each other as shown in FIG. 4B. One friction plate 73a is provided on the pier 20 side, the other friction plate 73b is provided on the bridge girder 10 side, and one of the friction plates 73a and 73b is hydraulically An actuator 74 such as a cylinder is provided so as to be able to contact and separate from the other friction plate 73a.

  5A, when the friction plates 73a and 73b are separated from each other, relative movement between the upper sliding plate 64 and the lower sliding plate 63 is allowed, and the end portions 10a and 10b of the bridge girder 10 are separated from the pier 20. As a result, the relative movement of the ends 10a and 10b of the bridge girder 10 with respect to the bridge pier 20 is allowed. On the other hand, when the friction plates 73a and 73b come into contact with each other as shown in FIG. Relative movement with the lower sliding plate 63 is restricted and the ends 10a and 10b of the bridge girder 10 are connected to the pier 20 and, as a result, relative movement of these ends 10a and 10b with respect to the pier 20 is restricted.

  By the way, the seismic motion detection unit in the seismic motion sensor is fixed to the footing 30 or the ground G in the vicinity of the footing 30, and the seismic motion detection signal output from the sensing unit is a computer (not shown) via a signal line. ). Then, the computer controls the operation of the actuator 74 based on this detection signal.

  That is, until the detection signal of seismic motion of level 2 or higher is input from the sensing unit to the computer, as shown in FIG. 5A, the pair of friction plates 73a and 73b are maintained apart from each other. 74 is controlled, so that the relative movement of the ends 10 a and 10 b of the bridge girder 10 with respect to the pier 20 is allowed. However, when a seismic motion detection signal of level 2 or higher is input, the computer controls the actuator 74 to bring the friction plates 73a and 73b into contact with each other as shown in FIG. The relative movement of the ends 10a and 10b of the bridge girder 10 with respect to the pier 20 is restricted. Incidentally, the computer has a CPU, a memory, etc., and the CPU that reads the control program stored in the memory controls the motor, etc., that is the drive source of the actuator 74 based on the control program, The above operation is executed.

<<<< About the effect of horizontal seismic isolation device 40 for bridge piers and horizontal seismic isolation device 60 for bridge girders >>
If such a horizontal seismic isolation device 40 for bridge piers and a horizontal seismic isolation device 60 for bridge girders are provided, the occurrence of a large earthquake (here, it is assumed that a ground motion of level 2 or higher) occurs and It becomes easy for a person, a vehicle, etc. to remain stably on the bridge girder 10 in any normal time. Details are as follows.

  First, as shown in FIG. 6A, the bridge girder horizontal seismic isolation device 60 allows relative movement in the horizontal direction between the bridge girder 10 and the bridge pier 20 until the level 2 or higher earthquake motion is received. In the seismic isolation device 40, the horizontal relative movement between the bridge pier 20 and the footing 30 is restricted. That is, the bridge girder 10 moves relative to the pier 20 in the horizontal direction, but the pier 20 does not move relative to the footing 30 in the horizontal direction.

  Therefore, in the normal time when there is no earthquake motion of level 2 or higher, the bridge pier 20 is not subjected to horizontal vibration, and only the bridge girder 10 is horizontally vibrated, so that the bridge girder 10 is horizontally isolated. For this reason, during this horizontal seismic isolation, the maximum amplitude of the horizontal vibration of the bridge girder 10 supported by the pier 20 is reduced by the amount that the pier 20 does not vibrate horizontally. As a result, the horizontal vibration of the bridge girder 10 is reduced during normal times. It is suppressed, and it becomes easy for a person and a vehicle to stay on bridge girder 10 stably.

  On the other hand, after receiving an earthquake motion of level 2 or higher, the state is switched to the opposite state. That is, as shown in FIG. 6B, the horizontal seismic isolation device 40 for bridge piers allows relative movement in the horizontal direction between the pier 20 and the bridge girder 10, but the bridge girder 10 in the horizontal seismic isolation device 60 for bridge girder. And the horizontal relative movement of the pier 20 are restricted. In other words, the pier 20 moves relative to the footing 30 in the horizontal direction, but the bridge girder 10 does not move relative to the pier 20 in the horizontal direction.

  Therefore, at the time of the occurrence of the large earthquake and thereafter, all the bridge girders 10 and the piers 20 are connected and integrated to behave like one large mass point and vibrate on the footing 30. As a result, it becomes easier for people and vehicles to stay on the bridge girder 10 stably. Moreover, since the drop-off of the bridge girder 10 from the bridge pier 20 is effectively prevented, people and vehicles can easily stay on the bridge girder 10 stably.

  By the way, the bridge girder horizontal seismic isolation device 60 provided with the second stopper 70 also has an effect that the bridge girder 10 can easily pass after receiving a level 2 or higher earthquake motion.

  That is, when a large level 2 earthquake motion is input to the viaduct 1, the ends 10 a and 10 b of the bridge girder 10 usually move greatly in the girder length direction with respect to the pier 20. Then, a large gap S is formed between the end 10a of the bridge girder 10 and the end 10b of the bridge girder 10 adjacent to the end 10a of the bridge pier 20 in the girder length direction. As a result, the viaduct 1 passes through. It becomes difficult to do.

  In this regard, if the second stopper 70 is provided, the second stopper 70 is connected to the ends 10a and 10b of the bridge girder 10 and the pier 20 as shown in FIG. Is restricted, so that the expansion of the gap S between the end portion 10a and the end portion 10b adjacent to each other in the girder length direction is suppressed, and as a result, the viaduct 1 is subjected to seismic motion of level 2 or higher. It will be easy to pass.

=== Modification ===
7 to 8B are explanatory views of a first modification of the above-described embodiment. FIG. 7 shows a side view of the bridge 1 ′ according to the first modification, and FIGS. 8A and 8B show enlarged views of the upper portion of the pier 20 respectively.

  This first modification is different from the above-described embodiment in the following two points, particularly regarding the bridge girder horizontal seismic isolation device 60.

  First, as a first difference, in the above-described embodiment, the both ends 10a and 10b of the bridge girder 10 in the girder length direction are supported by the pier 20 so as to be relatively movable in an arbitrary direction in the horizontal direction. In the first modification, as shown in FIG. 7, the front end portion 10a of the bridge beam 10 in the direction of the beam length is a so-called rotation support member 80 (a support member that restricts relative movement without transmitting moment). ) Is supported by the pier 20 so as not to move relative to the bridge pier 20, while the rear end portion 10 b is moved in the longitudinal direction by a so-called moving support member 90 (a support member that allows relative movement in a predetermined direction without transmitting moment). Only supported by the pier 20 so as to be relatively movable.

  Further, as a second difference, in the second stopper 70 of the above-described embodiment, the end portions 10a and 10b of the bridge girder 10 and the bridge pier 20 are cut off by operating the clutch mechanism 72 based on the seismic motion sensor. In the second stopper 95 of this first modification, the rear end portion 10b of the bridge girder 10 and the pier 20 are connected from the edge cut state to the connected state without using the seismic motion sensor or the clutch mechanism 72. (See FIGS. 8A and 8B).

  Except for these two differences, the second embodiment is the same as the above embodiment, and therefore, the same components are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 8A, the rotation support member 80 that supports the front end portion 10 a of the bridge girder 10 includes, for example, a bracket 81 fixed to the front end portion 10 a and a bracket 82 fixed to the pier 20. . Each of the brackets 81 and 82 is formed with a through hole extending in the direction of the width of the beam, and the connecting pin 83 is inserted into the through hole so that the end 10a is relative to the pier 20. It is linked immovably.

  On the other hand, as shown in FIG. 8A, the movement support member 90 that supports the rear end portion 10b of the bridge girder 10 includes a rotation support member 80 having the same configuration as described above, and in addition, a sliding support member 90 is provided at the lower portion thereof. A support member 62 and a guide member (not shown) are provided. The sliding support member 62 has the same configuration as described above, that is, from a lower sliding plate 63 made of a Teflon plate fixed to the upper surface 20a of the pier 20 and a stainless plate fixed to the lower surface of the rotation support member 80. And an upper sliding plate 64. On the other hand, the guide member is a pair of structural steel members and the like that are linearly arranged along the girder length direction on both sides in the girder width direction of the sliding support member 62 on the upper surface 20a of the pier 20 and the like. The upper sliding plate 64 of the sliding support member 62 is restricted so that it cannot move in the width direction. Therefore, when the upper sliding plate 64 and the lower sliding plate 63 slide in the girder length direction while abutting the sliding surfaces, the rear end portion 10b of the bridge girder 10 is relative to the pier 20 in the girder length direction. Only movement is allowed. Although not shown in FIGS. 8A and 8B, a reversion spring 66 is provided at the rear end portion 10b of the bridge girder 10 as in the above-described embodiment.

  Here, since only the rear end portion 10b of the bridge girder 10 can be moved relative to the pier 20 as a matter of course, the second stopper 95 is provided for the front end portion 10a fixed to the pier 20. However, it is provided only for the rear end portion 10b that is allowed to move relative to the pier 20. The second stopper 95 allows the relative movement in the girder length direction between the rear end portion 10b and the pier 20 until receiving a ground motion of level 2 or higher, but after receiving a ground motion of level 2 or higher. And restricting the relative movement.

  As a specific configuration of the second stopper 95, for example, as shown in FIG. 8A, a bracket 96 fixed to the rear end portion 10b of the bridge girder 10 and a bracket 96 are inserted into a through hole penetrating vertically. The pin member 97 whose lower end is in contact with and supported by the upper surface 20a of the pier 20 and the pit formed in the upper surface 20a of the pier 20 at a position corresponding to the allowable limit of relative movement of the rear end portion 10b of the bridge girder 10 98 can be exemplified. The allowable limit of relative movement is an assumed displacement amount between the bridge pier 20 and the bridge girder 10 that may occur when subjected to level 2 earthquake motion, and is calculated by an appropriate calculation method.

  According to such a configuration, when the rear end portion 10b of the bridge girder 10 moves relative to the pier 20 until the relative movement amount of the allowable limit is reached, the pin member 97 is connected to the pier as shown in FIG. 8A. 20 is supported on the upper surface 20a of the bridge girder by sliding the lower end portion thereof, and moves relative to the pier 20 together with the rear end portion 10b of the bridge girder 10. When the relative movement amount reaches the allowable limit, as shown in FIG. The pin member 97 falls into the drop hole 98 formed at that position, and the lower part of the pin member 97 is caught in the drop hole 98. At this time, the upper part of the pin member 97 is inserted into the through hole of the bracket 96. Yes. Therefore, the pin member 97 is engaged with both the bracket 96 and the drop hole 98, and the rear end portion 10b of the bridge girder 10 is restricted from further relative movement.

  9A and 9B are side views of a modified example of the second stopper 95 described above. In the second stopper 95 described above, as shown in FIG. 8B, the pin member 97 is directly engaged with both the rear end portion 10 b and the pier 20 of the bridge girder 10, whereby the rear end portion 10 b is relatively moved with respect to the pier 20. 9A and 9B, in the second stopper 100 of the modified example of FIGS. 9A and 9B, both the rear end portion 10b of the bridge girder 10 and the front end portion 10a of the bridge girder 10 adjacent to the rear end of the rear end portion 10b. The second stopper 100 is engaged with the rear end portion 10b to connect the rear end portion 10b and the front end portion 10a to prevent the separation, and in addition to preventing the separation, the front end portion 10a further supports the rotation. By utilizing the fact that the member 80 cannot move relative to the pier 20, the relative movement of the rear end 10 b relative to the pier 20 is indirectly restricted.

  Specifically, as shown in FIG. 9A, when the relative movement amount of the rear end portion 10b is within an allowable limit, the rear end portion 10b of the bridge girder 10 and the front end portion 10a of the bridge girder 10 adjacent to the rear thereof are straddled. Thus, both end portions 100a and 100b of the second stopper 100 are stretched and supported. That is, both end portions 100a and 100b in the girder length direction of the second stopper 100 are placed and supported on the cradle 102 of the rear end portion 10b of the bridge girder 10 and the cradle 102 of the front end portion 10a of the bridge girder 10, respectively. Yes. The rear end portion 10b of the bridge girder 10 and the front end portion 10a of the bridge girder 10 are respectively provided with concave portions 104, 104 facing upward, respectively, at positions below the second stopper 100, and the second A pair of convex portions 106 and 106 are formed on the lower surface of the stopper 100 so as to correspond to the pair of concave portions 104 and 104.

  Accordingly, when the rear end portion 10b relatively moves and reaches the relative movement amount of the allowable limit, the rear end portion 100b and the front end portion 100a of the second stopper 100 are detached from the cradles 102 and 102 and fall downward. . When the relative movement amount of the rear end portion 10b returns to the vicinity of the original zero in the process in which the rear end portion 10b vibrates in the digit length direction due to seismic motion or the like, as shown in FIG. 9B, the second stopper The convex portions 106 and 106 of 100 are fitted into the concave portions 104 and 104 of the rear end portion 10b and the front end portion 10a, respectively, so that the rear end portion 10b of the bridge girder 10 and the front end portion 10a of the bridge girder 10 are connected. However, since the front end portion 10a is restricted by the rotation support member 80 so as not to be relatively movable in the girder length direction, the rear end is passed through the rotation support member 80. The relative movement of the portion 10b with respect to the pier 20 is indirectly restricted.

  Incidentally, examples of the shape of the concave portion 104 and the convex portion 106 include a conical shape and a triangular prism shape with the top portion facing downward.

=== Other Embodiments ===
As mentioned above, although embodiment of this invention was described, this invention is not limited to this embodiment, The deformation | transformation as shown below is possible in the range which does not deviate from the summary.

(A) In the above-described embodiment, the sliding support members 42 and 62 are used as the main body of the horizontal isolation device 40 for the bridge pier and the horizontal isolation device 60 for the bridge girder. However, the present invention is not limited to this, so-called rolling support. A member (including a plate member and a roller member such as a roller member such as a sphere or a cylinder that rolls in contact with the horizontal surface of the plate member) may be used.

(B) In the above-described embodiment, the continuous viaduct 1 is illustrated as an example of the bridge, but the present invention is not limited to this. That is, a plurality of bridge girders 10 are not continuous but may be a single bridge girder 10 or may be an ordinary bridge passed over a river instead of a road or railroad.

It is a side view of the bridge 1a with which two types of seismic isolation apparatuses 40a and 60a were attached. It is a side view of the bridge 1 which concerns on this embodiment. 3A to 3C are explanatory views of the horizontal pier seismic isolation device 40 for piers. 4A to 4C are explanatory views of the horizontal seismic isolation device 60 for bridge girders. 5A and 5B are explanatory diagrams of the second stopper 70. FIG. 6A is a diagram showing a state of the bridge 1 in a normal time without a seismic motion of level 2 or higher, and FIG. 6B is a diagram showing a state of the bridge 1 after receiving a seismic motion of level 2 or higher. It is bridge 1 'explanatory drawing of a 1st modification. 8A and 8B are side views of the upper part of the pier 20 of the bridge 1 'of the first modified example. 9A and 9B are side views of a further modified example of the second stopper according to the above-described first modified example.

Explanation of symbols

1 bridge, 10 bridge girder, 10a end, 10b end, 20 pier, 20a upper surface,
30 footings, 32 piles, 40 horizontal seismic isolation devices for bridge piers (pier support members),
42 Sliding bearing member, 43 Lower sliding plate, 44 Upper sliding plate, 46 Reversing spring,
50 First stopper, 51 Bracket, 51a Flange,
52 bracket, 52a flange, 53 shear pin, 54 retaining member,
60 Horizontal seismic isolation device for bridge girder (bridge girder bearing member), 62 Sliding bearing member,
63 Lower sliding plate, 64 Upper sliding plate, 66 Reverse spring, 70 Second stopper,
72 Relative movement control mechanism, 73a friction plate, 73b friction plate,
74 Actuator, 80 Rotation support member, 81 Bracket,
82 bracket, 83 connecting pin, 90 moving support member, 95 second stopper,
96 bracket, 97 pin member, 98 pit, 100 second stopper,
100a front end, 100b rear end, 102 cradle, 104 recess,
106 Convex part, G ground

Claims (3)

A bridge pier support member provided on a footing fixed to the ground and supporting the pier in a horizontal direction so as to be relatively movable; and a bridge girder support member provided on the pier and supporting the bridge girder in a horizontal direction so as to be relatively movable. A bridge,
The bridge girder support member allows relative movement of the bridge girder with respect to the pier, and the pier support member regulates relative movement of the pier with respect to the footing until it receives earthquake motion of a predetermined level or more.
The bridge girder support member restricts the relative movement of the bridge girder with respect to the pier, and the pier support member allows the relative movement of the pier with respect to the footing after receiving the earthquake motion of the predetermined level or more. Characteristic bridge. The bridge according to claim 1,
A plurality of the piers are arranged along the girder length direction of the bridge girder, and a pair of the piers adjacent to each other in the girder length direction are sequentially supported by the corresponding bridge girder.
After receiving the earthquake motion of the predetermined level or higher, the relative movement of the bridge girder with respect to the pier is restricted for all bridge girder. A bridge pier support member provided on a footing fixed to the ground and supporting the pier in a horizontal direction so as to be relatively movable; and a bridge girder support member provided on the pier and supporting the bridge girder in a horizontal direction so as to be relatively movable. A seismic isolation method for the bridge
The bridge girder support member allows relative movement of the bridge girder with respect to the pier, and the pier support member regulates relative movement of the pier with respect to the footing until it receives earthquake motion of a predetermined level or more.
The bridge girder support member restricts the relative movement of the bridge girder with respect to the pier, and the pier support member allows the relative movement of the pier with respect to the footing after receiving the earthquake motion of the predetermined level or more. Seismic isolation method for the bridge.