JP7756364B2 - Cushioning material - Google Patents

Description

The present invention relates to a buffer material, particularly a buffer material attached to a horizontal movement suppression member that suppresses the horizontal movement of a bridge girder.

To prevent bridges from collapsing, horizontal movement suppression members that suppress horizontal movement of the bridge girders are sometimes attached to the bridge piers. In this case, shock absorbers are attached to the horizontal movement suppression members to reduce the impact when the bridge girders collide with the horizontal movement suppression members.

Generally, a stepped through hole is formed on the surface of the buffer facing the bridge girder in a direction perpendicular to this surface, and the buffer material is attached by inserting a bolt through this through hole and screwing a nut onto it.

Patent Document 1 also describes how a buffer is attached to a bridge fall prevention wall (a horizontal movement suppression member) by embedding multiple mounting pieces with protruding upper and lower ends into the buffer so that they are flush with the mounting surface of the buffer, and then inserting anchor bolts into through-holes formed in each protruding end.

Patent Document 2 describes a method of installing a shock-absorbing rubber (buffer) on a concrete wall by embedding and adhesively fixing a bolt in the shock-absorbing rubber (buffer), attaching a mounting steel plate to the protruding upper end of the bolt using a nut, inserting the bolt into a through-hole formed in the mounting steel plate, and fixing the bolt to the concrete wall (horizontal movement suppression member).

Patent No. 3599906 JP 2012-251411 A

However, the gap between the buffers attached to the horizontal movement suppression members and the bridge girder is set to a distance that allows horizontal movement of the bridge girder, and is extremely narrow. This makes it nearly impossible to attach buffers to horizontal movement suppression members installed on bridge piers. As a result, horizontal movement suppression members with buffers already attached were installed on bridge piers. However, when replacing buffers due to deterioration over time or damage from earthquakes, the horizontal movement suppression members had to be removed from the piers, making the process of replacing the buffers complicated.

In light of the above, the present invention aims to provide a cushioning material that can simplify replacement work.

The cushioning material of the present invention is attached to a horizontal movement suppression member placed on a bridge pier, with a horizontal gap between it and the bridge girder. It is characterized by comprising a cushioning body formed with multiple through holes that penetrate in the vertical direction, multiple insertion members inserted into the through holes, locking members fixed to the portions of the multiple insertion members that protrude from the upper end of the cushioning body and move downward to removably lock onto the horizontal movement suppression member, and anti-detachment members fixed to the portions of the multiple insertion members that protrude from the lower end of the cushioning body and prevent each of the insertion members from falling out of the through holes.

With the cushioning material of the present invention, the locking member is locked to the horizontal movement suppression member by moving the cushioning material downward. Therefore, the cushioning material can be attached to the horizontal movement suppression member by moving the cushioning material, which is positioned above the horizontal movement suppression member at a predetermined position, downward. Therefore, unlike conventional methods that require horizontal work from the bridge girder toward the surface of the horizontal movement suppression member facing the bridge girder when attaching the cushioning material to the horizontal movement suppression member, it is now possible to attach the cushioning material to a horizontal movement suppression member installed on a bridge pier. Furthermore, because the cushioning material can be removed from a horizontal movement suppression member installed on a bridge pier, the work of replacing the cushioning material can also be simplified.

Furthermore, a locking member is fixed to the upper end of the insertion member, and a fall-prevention member is fixed to the lower end, so it is possible to reliably prevent the insertion member from falling off the buffer. Note that "moving downward" does not strictly mean moving downward in the vertical direction, but also includes movement in directions including diagonally downward.

In the cushioning material of the present invention, it is preferable that male threads are formed on the portions of the multiple insertion members that protrude from the lower end of the cushioning body, and that the anti-detachment members are fixed to the multiple male threads using nuts, respectively.

In this case, deformation of the buffer body can be more effectively prevented than when a fall-off prevention member is fixed to each insertion member. Furthermore, since the fastening is done using a nut, the fastening process is simple and it is easy to adjust the degree of tightening to the buffer body.

Furthermore, in the cushioning material of the present invention, it is preferable that male threads are formed on the portions of the multiple insertion members that protrude from the upper end of the cushioning body, and that the locking members are each fixed to the male threads using a nut.

In this case, the attachment is done using a nut, which simplifies the attachment process and makes it easy to adjust the degree of tightening relative to the buffer.

Furthermore, in the cushioning material of the present invention, for example, the locking members each have a hook-shaped portion, and the horizontal movement suppression members each have a portion at their upper part that engages with the hook-shaped portion.

1 is an explanatory diagram showing a bridge collapse prevention structure using a buffer material according to an embodiment of the present invention. Schematic longitudinal cross-section of a bridge collapse prevention structure. FIG. 10 is a schematic side view showing a state in which a buffer material is attached to the horizontal movement suppression member.

A horizontal movement suppression cushioning material 10 (hereinafter simply referred to as cushioning material 10) according to an embodiment of the present invention will be described with reference to Figures 1 to 3. Note that Figures 1 to 3 are diagrams for schematically explaining this embodiment, and the dimensions have been exaggerated.

The buffer material 10 is attached to a horizontal movement suppression member 20 installed on a bridge pier B with the aim of isolating bridge girder A, such as the main girder of a bridge such as an elevated bridge, and preventing the bridge from collapsing. The horizontal movement suppression member 20 suppresses the horizontal movement of bridge girder A, and the buffer material 10 is installed with a specified gap between it and bridge girder A. The buffer material 10 suppresses the impact when bridge girder A collides with the horizontal movement suppression member 20.

The horizontal movement suppression member 20 comprises a base bracket 21 fixed to the pier B and a buffer bracket 22 to which the buffer material 10 is attached.

The base bracket 21 is a box-shaped structure made by welding or other methods to a rectangular steel plate, with the side opposite the fixed side open and reinforced with multiple reinforcing plates. The base bracket 21 is fixed, for example, using nuts to a number of anchors that are pre-installed or later installed on a concrete pier B (not shown).

The buffer bracket 22 is formed by welding or other methods to a rectangular plate made of steel or the like. The buffer bracket 22 is fixed by welding or other methods to the upper plate 21a that forms the upper part of the base bracket 21. The buffer bracket 22 has a rectangular mounting plate 22a with a surface that contacts the buffer material 10. This mounting plate 22a and the upper plate 21a of the base bracket 21 are then connected by welding or other methods with a plurality of plate-shaped reinforcing plates 22b.

The cushioning material 10 includes a cushioning body 11, an insertion member 12, a locking member 13, and a fall prevention member 14.

The buffer 11 has a rectangular flat surface 11a that makes surface contact with the mounting plate 22a of the buffer bracket 22, and a flat surface 11b that is parallel to the flat surface 11a and faces the surface of the bridge girder A across a specified gap, and has an overall roughly rectangular plate shape.

The buffer 11 has multiple through-holes 11c that penetrate vertically when installed on the horizontal movement suppression member 20. Apart from the through-holes 11c, the buffer 11 may be the same as a conventional buffer, and may be made of, for example, rubber.

The insertion members 12 are inserted through the through holes 11c formed in the buffer body 11. The upper end 12a of the insertion members 12 protrudes upward from the upper end of the buffer body 11, and the lower end 12b of the insertion members 12 protrudes downward from the lower end of the buffer body 11. Male threads are formed on the upper end 12a and lower end 12b. The insertion members 12 may also be cut bolts (long-threaded bolts) with male threads formed along their entire length.

The locking member 13 is made by bending a rectangular piece of metal such as steel. The locking member 13 is configured so that by moving the buffer material 10 downward, the buffer material 10 can be locked to the horizontal movement suppression member 20, more specifically, to the upper end of the mounting member 22a of the buffer material bracket 22. The locking member 13 is also configured so that by moving the buffer material 10 locked to the horizontal movement suppression member 20 upward, the buffer material 10 can be removed from the locked horizontal movement suppression member 20.

The locking member 13 has a first piece 13b extending horizontally and having a through hole 13a formed therein, through which the upper end 12a of the inserting member 12 passes. With the underside of this first piece 13b abutting the upper end surface of the buffer body 11, the locking member 13 is fixed to the inserting member 12 by a nut 15 that threads onto the upper end 12a of the inserting member 12. In this way, by fixing the first piece 13b of the locking member 13 by the nut 15, the inserting member 12 is prevented from slipping out upward through the through hole 11c.

The locking member 13 further has a second piece 13c that extends upward from the first piece 13b. This second piece 13c is formed so that when the locking member 13 is fixed to the insertion member 12 with the nut 15, the surface of the mounting member 22a of the horizontal movement suppression member 20 facing the bridge girder A is flush or nearly flush with the surface 11a of the buffer body 11.

The locking member 13 further has a third piece 13d that continues from the second piece 13c and extends rearward toward the front bridge girder B. This third piece 13d is set to a length slightly longer than the thickness of the mounting plate 22a of the buffer bracket 22 to which the locking member 13 is hooked.

The locking member 13 further has a fourth piece 13e that extends downward from the third piece 13d. This fourth piece 13e is formed so that when the locking member 13 is fixed to the insertion member 12 with the nut 15, the surface of the fourth piece 13e facing the horizontal movement suppression member 20 is flush or nearly flush with the surface 11b of the buffer 11. In this way, the second to fourth pieces 13c to 13e are formed in a hook shape that surrounds the upper end of the mounting plate 22a of the buffer bracket 22. The upper end of the mounting plate 22a is linear, but is shaped to engage with this hook-shaped portion.

The anti-slip member 14 is a long, narrow rectangular piece made of steel or other material, with a width equal to or narrower than the thickness of the buffer body 11. The anti-slip member 14 has multiple through holes 14a formed in it, each corresponding to the position of the through holes 11c formed in the buffer body 11. The lower end portions 12b of the insertion members 12 are inserted into the respective through holes 14a, and the nuts 16 are threaded onto the lower end portions 12b, thereby fixing the anti-slip member 14 in contact with the lower end surface of the buffer body 11.

This prevents the insertion member 12 from slipping out upward through the through-hole 13a, and more effectively prevents deformation of the buffer 11 by the nut 16 than when the anti-fall-off member 14 is not present. The anti-fall-off members 14 may correspond to all of the through-holes 11c formed in the buffer 11, or multiple anti-fall-off members may be present in one buffer 10, with each anti-fall-off member corresponding to a portion of the through-holes 11c formed in the buffer 11. Alternatively, the anti-fall-off members may correspond to individual through-holes 11c, like washers.

The upper end surface of the buffer 11 may also be provided with a fall prevention member 14. In this case, the locking member 13 may be positioned on the upper surface of the fall prevention member 14. The fall prevention member 14 and the locking member 13 may also be integrated, i.e., the first piece 13b of the locking member 13 may be replaced with the fall prevention member 14. Furthermore, the end of the first piece 13b and the fall prevention member 14 facing the surface of the bridge girder A is set back a predetermined distance from the flat surface 11b of the buffer 11 so that they are not subjected to impact when the bridge girder A and the buffer 11 collide. This predetermined distance is set to be greater than or equal to the maximum deformation that can occur in the buffer 11 when the bridge girder A and the buffer 11 collide.

The following describes how to construct a bridge collapse prevention structure using the above-mentioned buffer material 10.

In this construction method, first, the horizontal movement suppression member 20 is installed at a predetermined position on the pier B.

Then, between the bridge girder A and the horizontal movement suppression member 20, the buffer material 10 is pushed back to the specified position while keeping the locking member 13 positioned above the upper end of the buffer material bracket 22.

Then, in this state, the buffer material 10 is moved downward so that the locking members 13 hook onto the upper end of the mounting plate 22a of the buffer material bracket 22. As a result, the second to fourth pieces 13c to 13e of each locking member 13 surround the upper end of the mounting plate 22a, and the buffer material 10 is attached to the horizontal movement suppression member 20. Note that between the bridge girder A and the upper end of the mounting plate 22a, which is the upper end of the horizontal movement suppression member 20, there is a gap in the vertical direction that allows at least the locking members 13 to move toward the center (hereinafter referred to as the rearward direction) with respect to the axial cross section of the bridge girder A.

In this installed state, the cushioning material 10 can move forward or backward, but is restricted by the reinforcing plate 22b. The position of the reinforcing plate 22b may also be determined so that the cushioning material 10 cannot move.

As explained above, when the horizontal movement suppression member 20 is installed on the pier B, the buffer material 10 is not attached to the horizontal movement suppression member 20. Therefore, compared to the conventional case in which the horizontal movement suppression member with the buffer material attached is installed on the pier B, the gap between the horizontal movement suppression member 20 and the bridge girder A is wider, which makes it possible to simplify the work of installing the horizontal movement suppression member 20.

In addition, the buffer material 10 can be removed from the horizontal movement suppression member 20 by moving the buffer material 10 upward and then moving it toward the front. In this way, the buffer material 10 can be freely attached and detached to the horizontal movement suppression member 20 installed on the pier B. This makes it easier to replace the buffer material 10 compared to conventional methods where the horizontal movement suppression member had to be removed from the pier B when replacing the buffer material.

The present invention is not limited to the cushioning material 10 described above and can be modified as appropriate. For example, the specific configuration of each component of the cushioning material 10 and the horizontal movement suppression member 20 is not limited to that described above. For example, the shape of the locking member 13 is not limited to that described above as long as it can be removed from the horizontal movement suppression member 20 by moving it downward, and it may have a rounded hook shape, for example.

We have also explained a case in which the buffer material 10 can be removed simply by moving it upward from the horizontal movement suppression member 20 installed on the pier B. However, this is not limited to this. For example, the buffer material 10 may be moved while the locking member 13 remains hooked to the upper end of the mounting plate 22a, so that the upward movement of the buffer material 10 is suppressed by a suppression member (not shown). Furthermore, the base bracket 21 of the horizontal movement suppression member 20 may be a flat plate that is placed on the pier B and secured in place by a number of anchors.

10... Horizontal movement suppression buffer material, buffer material, 11... buffer body, 11a, 11b... flat surface, 11c... through hole, 12... insertion member, 12a... upper end (portion protruding from the upper end of the buffer body), 12b... lower end (portion protruding from the lower end of the buffer body), 13... locking member, 13a... through hole, 13b... first piece, 13c... second piece, 13d... third piece, 13e... fourth piece, 14... anti-fall member, 14a... through hole, 15, 16... nut, 20... horizontal movement suppression member, 21... base bracket, 21a... upper plate, 22... buffer material bracket, 22a... mounting plate, 22b... reinforcing plate, A... bridge girder, B... bridge pier

Claims (3)

A buffer material that is replaceably attached to a horizontal movement suppression member arranged on a bridge pier with a horizontal gap between the bridge girder and the buffer material,
the horizontal movement suppression member includes a buffer bracket including a mounting plate having a surface against which the buffer material abuts;
The buffer material is a plate-shaped buffer body having a flat surface that is in surface contact with the mounting plate and a flat surface that is parallel to the flat surface and faces the surface of the bridge girder across a predetermined gap, and having a plurality of through holes that penetrate in the vertical direction;
a plurality of long threaded bolts inserted into the through holes, respectively;
a locking member that is fixed to each of the portions of the plurality of long-threaded bolts that protrude from the upper end of the buffer body and that is removably locked to the mounting plate when the buffer body moves downward , the locking member comprising: a first piece extending horizontally and having a through hole through which the upper end of the long-threaded bolt is inserted; a second piece extending upward from the first piece; a third piece extending rearward from the second piece relative to the front bridge girder; and a fourth piece extending downward from the third piece ;
and a fall prevention member fixed to each of the plurality of long-threaded bolts at a portion protruding from the lower end of the buffer body, to prevent each of the long-threaded bolts from falling out of the through hole. The cushioning material according to claim 1, characterized in that the portions of the plurality of long-threaded bolts that protrude from the lower end of the cushioning body are each formed with a male thread, and the anti-fall-out member is fixed to each of the plurality of male threads using a nut. The cushioning material according to claim 1 or 2, characterized in that the portions of the plurality of long-threaded bolts that protrude from the upper end of the cushioning body are each formed with a male thread, and the locking members are each fixed to the male thread using a nut.