Bridge collapse prevention device

Abstract

To provide an inexpensive bridge fall prevention device having readiness, no temperature dependency, etc., high impact absorption performance, easy maintenance and management, and simple structure.SOLUTION: A bridge fall prevention device S1 is provided with a first support member 10 to be attached to a bridge abutment P (lower structure), and a second support member 20 to be attached to a bridge girder G (upper structure) provided opposite to the first support member 10. The first support member 10 and the second support member 20 are rotatable to a PC steel bar 31 and are slidably and separably joined in the horizontal direction. An interposing plate 30 (interposing member) is provided between the first support member 10 and the second support member 20 in a state in which clamping force is imparted by the PC steel bar 31.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a bridge fall prevention device for preventing a bridge girder from falling.

Background Art

[0002] In bridges, in order to prevent the bridge girder (superstructure) from falling off the abutment and pier (substructure) during an earthquake, a bridge fall prevention device that connects the bridge girder and the abutment or the like is provided.

[0003] By the way, in a conventional bridge fall prevention device, when an excessive external force due to an earthquake force or the like is applied, a large impact force may act, and there has been a concern about damage or the like. As a countermeasure therefor, for example, a bridge fall prevention device with a three-dimensional bracket is known in which both ends of a damper using a viscous body are connected between a bridge girder and an abutment or the like via brackets (Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in a conventional bridge fall prevention device, since an oil damper is usually used, it has the following problems. That is, since the oil damper has a structure that absorbs energy by moving the oil sealed inside, it takes time to operate and has a problem of temperature dependence. In addition to the original mechanism of the bridge fall prevention device, it is necessary to provide an oil damper, so the structure is complicated and the entire device is enlarged, and the manufacturing cost has to be high, and maintenance management including inspection is also complicated.

[0006] From such a perspective, an object of the present invention is to provide a bridge-fall prevention device that has instant responsiveness, has no temperature dependence, etc., has high shock absorption performance, is easy to maintain, has a simple structure, and is inexpensive.

Means for Solving the Problems

[0007] The bridge-fall prevention device of the present invention for solving the above problems has a first support member for attaching to one of the upper structure or the lower structure, and a second support member provided opposite to the first support member for attaching to the other of the lower structure or the upper structure, and the first support member and the second support member are Via a fastening means that penetrates the first support member and the second support member slidable capable joined and is capable of approaching and separating within the range of the long hole formed in the second support member, configured to generate a frictional force corresponding to the relative displacement between the first support member and the second support member frictional and provided with frictional force generating means The frictional force generating means includes an interposed member having a central hole through which the fastening means penetrates and interposed between the first support member and the second support member. An impact absorbing member is provided on a part of the contact surface of the first support member or the second support member with the interposed member. By sandwiching the first support member and the second support member with a predetermined clamping force via the fastening means, the frictional force is generated between the first support member, the second support member, and the interposed member .

[0008] The bridge fall prevention device of the present invention for solving the above problems has a first support member for attaching to one of an upper structure or a lower structure, and a second support member provided opposite to the first support member for attaching to the other of the lower structure or the upper structure. The first support member and the second support member are slidably joined via a fastening means that penetrates the first support member and the second support member, and are capable of approaching and separating within the range of the long hole formed in the second support member. Frictional force generating means for generating a frictional force corresponding to the relative displacement between the first support member and the second support member is provided, and an impact absorbing member is provided on the attachment surface of at least one of the first support member and the second support member with the upper structure or the lower structure It may be configured as such.

[0009] Further, in the bridge-fall prevention device of the present invention, According to claim 2 the frictional force generating means may be configured to generate the frictional force between the first support member and the second support member by sandwiching the first support member and the second support member with a predetermined clamping force.

[0010] Further, in the bridge-fall prevention device of the present invention, According to claim 2 the frictional force generating means on the may be configured to be the first support member and the second support member sliding surface of, frictional force enhancing means is provided as described above.

[0011] Further, in the bridge-fall prevention device of the present invention, According to claim 2 in The frictional force generating means includes an interposed member having a central hole through which the fastening means penetrates and interposed between the first support member and the second support member. By sandwiching the first support member and the second support member with a predetermined clamping force via the fastening means, the frictional force is generated between the first support member, the second support member, and the interposed member it may be configured as such.

[0012] Further, in the bridge-fall prevention device of the present invention, A plurality of the interposed members are arranged in series or juxtaposed with a predetermined interval in the longitudinal direction of the first support member and the second support member it may be configured as such.

[0013] Further, in the bridge-falling prevention device of the present invention, The first support member has a base plate and side plates provided in the longitudinal direction at intervals in the width direction perpendicular to the base plate. The second support member includes a central plate provided in the longitudinal direction between the side plates, end plates provided at the ends of the central plate, and the shock absorbing members provided on the end plates. The hole of the fastening means that penetrates the side plates and also penetrates the central plate is formed as the long hole in the longitudinal direction. it may be configured as follows.

[0014] Further, in the bridge-falling prevention device of the present invention, A plurality of the central plates are provided side by side in the width direction and are provided at positions between the side plates. The interposed member is disposed between the central plate and the side plates. it may be configured as follows.

[0015] Further, in the bridge-falling prevention device of the present invention, The central plate, the side plates, and the modification member If it is configured to be arranged in parallel in the interval direction, the deformation performance in the width direction of the intervening member can be effectively suppressed, and the friction force generation effect can be improved, which is preferable.

[0016] Further, in the bridge-falling prevention device of the present invention, the friction force generation range of the friction force generation means is configured to be larger than the displacement range of the first support member and the second support member, so that the friction force generation means can be prevented from being damaged before the bridge-falling prevention function is lost, which is preferable. Further, in the bridge-falling prevention device of the present invention, the friction force generation means includes a first metal surface formed of a metal material different from the first support member provided on the sliding surface of the first support member, and a second metal surface formed of a metal material different from the second support member provided on the sliding surface of the second support member, and the first metal surface and the second metal surface may be formed of a metal-based sliding material of metal materials having different component compositions.

[0017] According to the present invention, since the friction force generation means is provided, friction force is generated according to the relative displacement of the first support member and the second support member, and when an external force such as an earthquake force acts, the operation of the bridge-falling prevention device is made gentle, and when the first support member and the second support member are displaced, the external force can be absorbed and attenuated by the friction force. Therefore, since it can be configured as a device that prevents bridge collapse while absorbing seismic energy, it is possible to prevent sudden impact force from acting on the present bridge-falling prevention device and causing damage to the bridge girder or abutment.

[0018] According to the Road Bridge Design Manual, in principle, a fall prevention structure and a displacement limiting structure should not be used in combination to avoid the loss of one function leading to the loss of the other function and to ensure each function. However, the Road Bridge Design Manual has an exception provision stating that when a structure that can ensure both functions independently is adopted, these may be used in combination. Since the present fall prevention device has a structure that can ensure the functions of the fall prevention structure and the displacement limiting structure independently, there is no problem.

Advantages of the Invention

[0019] According to the fall prevention device of the present invention, it has immediate responsiveness, has no temperature dependence, etc., has high impact absorption performance, is easy to maintain, and can have a simple structure and low cost.

Brief Description of the Drawings

[0020]

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Mode for Carrying Out the Invention

[0021] Hereinafter, with reference to the drawings, an embodiment of the bridge-fall prevention device S1 of the present invention (hereinafter referred to as "the present bridge-fall prevention device") will be described in detail. In the description of the drawings, the same reference numerals are given to the same elements, and duplicate descriptions are omitted.

[0022] (Configuration of the present bridge-fall prevention device) The present bridge-fall prevention device S1 is provided between the bridge girder G of the bridge B (first embodiment) and the abutment P, and is used to prevent the bridge girder G from falling by connecting the bridge girder G and the abutment P, and is provided at a plurality of predetermined locations. In the present embodiment shown in FIGS. 1 and 2, the present bridge-fall prevention device S1 is provided between the concrete wall G1 protruding from the lower surface near the support portion J at the end of the bridge girder G and the opposing upper side surface of the abutment P. And regarding the locations where it is attached by the anchor bolts 41 at the attachment portions 15 and 25 of the first support member 10 and the second support member 20 described later, examples are shown here.

[0023] First, the configuration of the present bridge-fall prevention device S1 will be described. As shown in FIGS. 3 and 4, the present bridge-falling prevention device S1 mainly includes a first support member 10, a second support member 20 provided to face the first support member 10 in the horizontal direction (X direction), an interposed plate 30 (interposed member) which is a frictional force generating means, and a PC steel bar 31 (tightening means).

[0024] The first support member 10 includes a base plate 11 formed in the width direction (Y direction), two side plates 12 provided in a direction perpendicular to the base plate 11, and a mounting portion 15 provided on the base plate 11. The two side plates 12 are formed at intervals from each other in the direction (X direction) perpendicular to the base plate 11. From the central portions of the side plates 12 on both sides, steel bar insertion holes 12a for inserting the PC steel bar 31 are formed at positions slightly separated from the opposite side (hereinafter referred to as the "tip side") of the base plate 11. In addition, bolt small holes 12b for inserting the mounting bolts 32 of the interposed plate 30 are formed at equal interval positions with the steel bar insertion holes 12a as the center on the side plates 12, and bolt holes 12c for inserting the side fixing bolts 33 are formed on the base end side.

[0025] The second support member 20 includes a central plate 22 in the longitudinal direction, an end plate 21 provided at the end of the central plate 22 on the side of the first support member 10, and a mounting portion 25 provided at the end of the central plate 22. A long hole 22a is formed in the longitudinal direction at the center of the central plate 22, and an impact absorber 23 (impact absorbing member) is provided on the contact surface with the interposed plate 30 inside the end plate 21 (hereinafter, the T-shaped member formed by the end plate 21, the central plate 22, and the impact absorber 23 may be referred to as the "T-shaped part 24"). Note that the first support member 10 and the second support member 20 are formed of steel plates of the same steel type.

[0026] In addition, the mounting portions 15 and 25 of the first support member 10 and the second support member 20 are formed in the same shape as an example. The mounting portion 15 of the first support member 10 is formed by a vertical plate 16 and horizontal plates 17 that are horizontally arranged at predetermined intervals in the height direction of the vertical plate 16. And a central hole 17a is formed in the central portion of each horizontal plate 17. A base plate 11 is fixed between the two horizontal plates 17. Also, a cylinder 18 is inserted into the central hole 17a, and a pin 19 is inserted into the cylinder 18.

[0027] Also, the mounting portion 25 of the second support member 20 is formed by a vertical plate 26 and horizontal plates 27 that are horizontally arranged at predetermined intervals in the height direction of the vertical plate 26. And a central hole 27a is formed in the central portion of each horizontal plate 27. An end portion of the central plate 22 is fixed between the two horizontal plates 27. Also, a cylinder 28 is inserted into the central hole 27a, and a pin 29 is inserted into the cylinder 28.

[0028] The interposed plate 30 is a steel plate having a substantially square shape. This interposed plate 30 is coated in a circular range, for example, with polytetrafluoroethylene (PTFE) at the central portion of one surface, forming a circular coating portion 30a. Also, a central hole 30b for inserting a PC steel bar 31 is formed at the center of this circular coating portion 30a. The diameter of the circular coating portion 30a is formed to be longer compared to the length of the long hole 22a of the central plate 22 of the second support member 20, and the friction generating range (operating range) of the friction generating means is larger compared to the displacement ranges of the first support member 10 and the second support member 20.

[0029] The interposed plate 30 is disposed opposite to the side plate 12 such that one end thereof is substantially aligned with the tip side of each side plate 12. Further, the interposed plate 30 is disposed such that the circular coating portion 30a faces the central plate 22 through the central plate 22. The interposed plate 30 is integrally attached to the side plate 12 by inserting mounting bolts 32 that communicate with four bolt small holes 12b of the side plate 12. The second support member 20 is provided such that when the side plates 12 or the central plate 22 of both the first support members 10 are located at the moving ends, the end face of the end plate 21 absorbs an impact and comes into contact therewith.

[0030] Further, the positions of the steel bar insertion holes 12a in the side plates 12 of the first support member 10, the central holes 30b in each intermediate plate 30, and the long holes 22a in the central plate 22 of the second support member 20 are made to coincide, and a PC steel bar 31 is inserted through each hole. Then, by fastening with a predetermined tension using the PC steel bar 31, the first support member 10 and the second support member 20 are joined via the intermediate plate 30. Further, side fixing bolts 33 are inserted through the bolt holes 12c in the two side plates 12, and a clamping force is applied between the two side plates 12. Note that reference numeral 14 indicates a backing plate interposed between the head of the side fixing bolt 33 and the side plate 12 for fastening the side fixing bolt 33 to the side plate 12.

[0031] With the above configuration, the side plate 12 of the first support member 10 and the central plate 22 of the second support member 20 are supported so as to be rotatable with respect to the PC steel bar 31 which is a horizontal rotation axis, and are slidable and separable in the horizontal direction within the range of the long holes 22a formed in the central plate 22 of the second support member 20. Note that the coefficient of kinetic friction of the circular covering portion 30a of the intermediate plate 30 is smaller than the coefficient of kinetic friction of the central plate 22 of the second support member 20. However, due to the tension of the PC steel bar 31, the side plate 12, the intermediate plate 30, and the central plate 22 are clamped, and a predetermined clamping force is applied to the intermediate plate 30. Therefore, when the side plate 12 of the first support member 10 and the central plate 22 of the second support member 20 are displaced, a frictional force of a predetermined magnitude is generated. Further, the range of the region where the circular covering portion 30a is formed is wider than the range of the region of the long holes 22a.

[0032] (Operation and Effect of this Bridge Fall Prevention Device) Subsequently, the operation of this bridge fall prevention device S1 will be described. For example, when seismic forces (external forces) act on the bridge girder G and the abutment P during an earthquake, displacements will occur in the bridge girder G and the abutment P according to the magnitude and direction of the seismic forces. At this time, this bridge-fall prevention device S1 rotates by vertically displacing the side plate 12 of the first support member 10 and the central plate 22 of the second support member 20 with the center of the PC steel bar 31 as the rotation center (Fig. 5). Further, this bridge-fall prevention device S1 separates the side plate 12 of the first support member 10 and the central plate 22 of the second support member 20 in the horizontal direction within the range of the long hole 22a of the central plate 22 of the second support member 20, thereby displacing following the seismic forces and preventing the bridge girder G from falling off the abutment P (Figs. 6 and 7).

[0033] At this time, in this bridge-fall prevention device S1, the intermediate plate 30 is clamped by the axial force of the PC steel bar 31, and the movement of the intermediate plate 30 at the circular covering portion 30a, which serves as a sliding surface (contact surface) with the central plate 22 of the second support member 20, is restricted. Therefore, in this bridge-fall prevention device S1, when the central plate 22 of the second support member 20 is displaced, frictional force is generated through the circular covering portion 30a, and this frictional force can absorb and attenuate the impact force acting on this bridge-fall prevention device S1 due to the seismic forces.

[0034] Thus, according to this bridge-fall prevention device S1, friction force generating means as a damping mechanism that generates friction force by the action of the intermediate plate 30 provided with the circular covering portion 30a and the PC steel bar 31 is provided according to the relative displacement between the first support member 10 and the second support member 20. Therefore, when an external force such as a seismic force occurs and this bridge-fall prevention device S1 operates and the first support member 10 and the second support member 20 are displaced, the external force can be attenuated by the frictional force, and it is possible to prevent a sudden impact force from acting on this bridge-fall prevention device S1. Therefore, a simple and inexpensive structure can be realized, and compared with the conventional bridge-fall prevention device using a damper, it has excellent responsiveness, a structure that does not have temperature dependence, and it is possible to enhance the impact absorption performance.

[0035] FIG. 8 is a graph showing the relationship between the displacement amount of the present bridge-falling prevention device S1 and the impact force acting on a bridge (such as a bridge girder or a bridge abutment, etc.). According to this figure, in the case of a bridge-falling prevention device without a frictional force generating means, when the displacement amount reaches the assumed limit, the impact force acts suddenly. On the other hand, in the case of the present bridge-falling prevention device S1, since the impact force acts gently, it is understood that damage to the bridge can be effectively prevented.

[0036] Also, in the present bridge-falling prevention device S1, an impact absorber 23 is provided on the contact surface of the end of the interposed plate 30 inside the end plate 21 of the second support member 20. Therefore, even when the first support member 10 and the second support member 20 separate within the assumed limit range, the action of the impact absorber 23 can effectively prevent an impact force from acting on the present bridge-falling prevention device S1, and damage to it can be prevented (FIG. 8).

[0037] Also, in the present bridge-falling prevention device S1, the diameter of the circular covering portion 30a is formed to be longer than the length of the long hole 22a of the central plate 22 of the second support member 20. Therefore, in the present bridge-falling prevention device S1, the frictional force generation range (operating range) of the frictional force generating means is larger than the displacement range of the first support member 10 and the second support member 20. By configuring it in this way, in the present bridge-falling prevention device S1, without complicating the member configuration and without incurring excessive manufacturing costs, the friction damping effect can be made to affect even after the bridge-falling prevention function is lost, the action of the frictional force generating means can be continued for a long time, and damage can be prevented.

[0038] (Other embodiments of the present bridge-falling prevention device, etc.) The embodiments according to the present invention have been described above. However, the present invention is not limited to the foregoing embodiments, and each of the above-described components can be appropriately changed without departing from the spirit of the present invention.

[0039] For example, either the first support member or the second support member may be attached to the upper structure or the lower structure, and the other may be attached to the lower structure or the upper structure, as long as it is interposed between the upper structure and the lower structure.

[0040] Regarding this point, in the above embodiment, the present bridge-falling prevention device S1 has been described by taking as an example the case where the attachment portion 15 of the first support member 10 is attached to the abutment P of the first embodiment and the attachment portion 25 of the second support member 20 is attached to the bridge girder G. However, when applying the present bridge-falling prevention device S1 to the bridge BB of the second embodiment having a space between the floor slab GG2 and the lateral girder GG1 at the end (FIGS. 9 and 10), the attachment portion 25 of the second support member 20 can be attached to the end of the abutment PP, and the attachment portion 15 of the first support member 10 can also be attached to the lateral girder GG1. That is, in the bridge BB of the second embodiment, the attachment portion 25 of the second support member 20 may be attached to the concrete wall portion PP1 protruding from the upper portion of the abutment PP, and the attachment portion 15 of the first support member 10 may be attached to the lower end portion inside the lateral girder GG1.

[0041] In addition, for the first support member, the second support member, the frictional force generating means, the frictional force enhancing means, and the shock absorbing member described in the claims, as long as they have a basic configuration and exhibit their functions and effects, various components can be used, and their forms (shape, dimensions, material, etc.) can be determined as appropriate.

[0042] In particular, the first support member and the second support member may be configured to be rotatably supported with respect to a horizontal rotation axis by the action of an external force caused by an earthquake force or the like, and to be appropriately displaceable so as to be able to approach and separate in the horizontal direction. The displacement form, displacement amount, etc. can be determined as appropriate according to the magnitude of the assumed external force. Note that the first support member and the second support member can also be configured to rotate in any direction by using a universal joint. In addition, the first support member and the second support member can be configured to be slidable while being in direct contact with each other, or can be configured to be slidable indirectly via an intermediate member as in the present embodiment.

[0043] Moreover, the frictional force generating means may be any means that generates a frictional force corresponding to the relative displacement of the first support member and the second support member in any direction. Regarding the first support member and the second support member, various means can be used, such as using a member with a large coefficient of kinetic friction, or coating at least one of them with an appropriate material, and interposing an intermediate member between the first support member and the second support member. In particular, it is also preferable to provide a frictional force enhancing means such as forming a rough surface or a plurality of uneven portions on the sliding surface of the first support member or the second support member.

[0044] Note that the bridge-falling prevention devices according to the second to sixth embodiments will be described below with reference to FIGS. 11 to 17. Members having the same configuration already described in the embodiments shown below are denoted by the same reference numerals as those of the bridge-falling prevention device according to the first embodiment, and the description thereof will be omitted as appropriate. As shown in the present bridge-falling prevention device S2 of the second embodiment (FIG. 11), a configuration may be adopted in which the intermediate plates 30 (intermediate members) and the PC steel bars 31 (tightening means), which are a plurality of frictional force generating means, are continuously arranged in the longitudinal direction of the side plate 212 of the first support member 210 (a configuration in which they are arranged side by side without a gap between adjacent intermediate plates 30). (Reference numeral 222a indicates a long hole formed at a predetermined position in the center plate 222 of the second support member 220). By adopting the above configuration, the deformation in the longitudinal direction of the intermediate plate 30 can be effectively suppressed, and the frictional force generating effect can be improved.

[0045] Furthermore, a configuration may be adopted in which a plurality of frictional force generating means are arranged side by side in the spacing direction between the first support member and the second support member. For example, as shown in the present bridge-falling prevention device S3 of the third embodiment (FIG. 12), a case will be described in which a plurality of intervening plates 330 are provided in the width direction of the first support member 310 and the second support member 320.

[0046] In this case, between two side plates 312 corresponding to the side plates 12 on both sides of the first support member 10 in the main bridge girder falling prevention device S1 of the first embodiment, a central plate 313 is provided (reference numeral 311 indicates a base plate). Also, two T-shaped portions 324 having the same structure as the T-shaped portion 24 constituting the second support member 20 (reference numerals 321 indicate end plates and 323 indicate shock absorbers 323 respectively) extend from the attachment portion 325.

[0047] And each T-shaped portion 324 is inserted between each side plate 312 and the central plate 313 of the first support member 310 so as to be slidable. Also, between the side plate 312 of each first support member 310 and the central plate 322 of the second support member 320, and between the central plate 313 of each first support member 310 and the central plate 322 of the second support member 320, a total of four intervening plates 330 are interposed, whereby the intervening plates 330 are arranged side by side in the width direction between the first support member 310 and the second support member 320 (reference numeral 331 is a PC steel bar for imparting a clamping force to each member, and 322a respectively indicates a long hole formed in the central plate 322). With the above configuration, when the circular covering portions 330a of the intervening plates 330 slide with the central plates 313 and 322, frictional force is generated through the circular covering portions 330a.

[0048] Note that the structures of the attachment portions 315 and 325 of the first support member 310 and the second support member 320 are the same as the structures of the attachment portions 15 and 25 in the present bridge-falling prevention device S1 of the first embodiment. Also, regarding the intervening plates, they can be formed by dividing them into appropriate dimensions such as having a laminated structure, arranging a plurality of them, or having the whole covered with a covering material. Further, the circular covering portions 30a and 330a may be covered so as to have a rectangular or elliptical shape or the like.. Also In addition, the method of forming the circular covering portions 30a and 330a can be to combine metals and resins with different performances, such as combining stainless steel (SUS) with tetrafluoroethylene resin (PTFE) and polyamide, combining steel materials with different properties, and combining high-strength brass steel with stainless steel, PEEK with stainless steel, PBN with stainless steel, etc. Various combinations of constituent materials can be used. Thus, according to the present bridge-falling prevention device S3 of the third embodiment, deformation in the width direction of the interposed plate 330 can be effectively suppressed, and the friction force generation effect can be improved.

[0049] In addition, in order to enable the stable operation of the friction force generation means, it is desirable to make the dynamic friction coefficient constant. However, it is not always necessary to use a material with a larger dynamic friction coefficient for the interposed member than the first support member or the second support member. As in the above embodiment, in order to facilitate control, when a material with a smaller dynamic friction coefficient than the first support member and the second support member is used for the interposed member, it is possible to cope by setting the magnitude of the generated friction force by applying an appropriate clamping force.

[0050] In addition, the mounting position, the number of mountings, the mounting method, etc. of the present bridge-falling prevention device can be appropriately determined according to the form of the bridge to which it is mounted.

[0051] In addition, for the impact absorbing member provided on a part of the contact surface between the interposed member and the first support member or the second support member, and on the mounting surface between at least one of the first support member and the second support member and the superstructure or the substructure, it can also be configured as a member with a desired material and shape, such as various elastic bodies (low-rebound rubber, polyurethane, etc.).

[0052] Regarding this point, for example, as shown in the present bridge-falling prevention device S4 of the fourth embodiment (FIG. 13), a configuration can also be adopted in which shock absorbers 42 are interposed between the attachment portions 15 and 25 of the first support member 10 and the second support member 20 and the bridge girder G and the abutment P. By adopting the above configuration, it becomes possible to effectively prevent an impact force from acting on the present bridge-falling prevention device S4 due to the action of the shock absorbers 42, and damage thereto can be prevented (FIG. 8).

[0053] Furthermore, as shown in FIG. 14 regarding the fifth embodiment, the present bridge-falling prevention device S5 may be configured such that one end 30B1 of the interposed plate 30B is formed in an arc shape. Also, the present bridge-falling prevention device S5 may be configured such that stainless steel plates 20b, 20b, which are metal-based sliding members formed in a planar shape at positions facing the circular covering portions 30a, 30a on the front and back surfaces of the second support member 20, are attached as mating plate members of the circular covering portions 30a, 30a of the metal-based manual member. That is, the stainless steel plates 20b and the circular covering portions 30a of the interposed plate 30 may be formed of different metal-based sliding members so as to face each other to form a sliding surface. By forming one end 30B1 of the interposed plate 30B in an arc shape, even when the first support member 10 and the second support member 20 are in a state of having moved from the initial state as shown in FIG. 6, for example, the shock absorbers 23 can abut evenly against one end 30B1 of the interposed plate 30B. Also, it is more preferable that the shock absorbers 23 and the end plates 21 are formed in an arc shape in accordance with the shape of one end 30B1 of the interposed plate 30B. Furthermore, by forming the sliding surface as a friction generating means with metal-based sliding members having different component compositions, seizure during sliding can be eliminated.

[0054] Next, the sixth embodiment will be described with reference to FIGS. 15 to 17. In this bridge-fall prevention device S6, as the frictional force generating means, a covering portion 30c which is a first metal surface formed of a metal material having a component composition different from that of the first support member 10 provided on the sliding surface of the first support member 10, and a mating plate member which is a second metal surface formed of a metal material having a component composition different from that of the second support member 20 provided on the sliding surface of the second support member 20 are formed together with the PC steel bar 31. And, in this bridge-fall prevention device S6, the shape of the intervening plate 30C is formed such that one end 30C1 is arc-shaped and the other end is rectangular in plan view. Here, the covering portions 30c, 30c may be configured to be rectangular in plan view. These covering portions 30c, 30c are formed of a metal sliding material and are installed on one side and the other side with the long hole 22a interposed therebetween. That is, the covering portions 30c, 30c are arranged such that there are two on one intervening plate 30 and two on the other intervening plate 30C. Further, on the front and back surfaces of the second member 20 facing the covering portions 30c, 30c, a mating plate member which is a metal material having good seizure resistance, affinity, etc. with respect to the metal sliding material, for example, a metal sliding material such as a stainless steel plate 20c, is preferably set.

[0055] As the metallic sliding materials in the covering parts 30c, 30c, a fixed lubricant dispersion type sintered material, a copper-based powder sintered material, etc. can be used. The covering parts 30c, 30c are connected to the interposed plates 30C, 30C as sliding surfaces by welding or sintering. The covering parts 30c, 30c are formed in a rectangular shape, so they are easy to handle because they can be prepared by linearly cutting thin plates at regular intervals as compared with the case of forming them in a circular shape. Note that the covering parts 30c, 30c are formed of a metallic material having a different composition from the metallic material used for the interposed plates 30C, 30C. Also, the stainless steel plate 20c is formed of a metallic material having a different composition from the metallic material of the end plate 21 of the second support member 20. That is, since the covering parts 30c, 30c and the interposed plates 30C, 30C have different roles, it is preferable to select a metallic material having a component composition suitable for that role. Similarly, for the end plate 21 of the second support member 20 and a mating plate material such as the stainless steel plate 20c, since they have different roles, it is preferable to select a metallic material having a component composition suitable for that role. Note that the metallic materials having different component compositions refer not only to those having different contained components, but also to metallic materials whose functions change due to different contents even though they are metallic materials having the same contained components.

[0056] Note that the metallic sliding material can also be applied to the first embodiment and the fourth embodiment already described. Also, although the covering parts 30c, 30c have been described as rectangular, if they are in a shape that can be used as a sliding surface, such as a trapezoid, a parallelogram, an arc shape, an oval shape, etc., they can be used in a configuration where two are installed with the long hole 22a sandwiched between one interposed plate 30C. Further, as described in the first embodiment, in the case of forming a circular covering part 30a with a long hole corresponding to the long hole 22a in the center and installing one on one interposed plate 30C, the outer shape thereof may be made similar to that of the interposed plate 30.

Explanation of Reference Numerals

[0057] S1~S6 Fall prevention device B, BB Bridge G, GG Bridge girder P, PP Abutment 10, 210, 310 First support member 11,311 Base plate 12,212,312 Side plate 313 Central plate 15 Mounting part 20,220,320 Second support member 20b,20c Stainless steel plate (second metal surface: friction generating means) 21,321 End plate 22,222,322 Central plate 322 Side plate 22a,222a,322a Long hole 23,42 Shock absorber (shock absorbing member) 25 Mounting part 30,330 Interposed plate (interposed member: friction generating means) 30a,330a Circular covering part 30c Covering part (first metal surface: friction generating means) 31,331 PC steel bar (tightening means: friction generating means)

Claims

1. a first support member for attachment to one of an upper structure or a lower structure; a second support member provided opposite to the first support member for attachment to the other of the lower structure or the upper structure, and the first support member and the second support member are slidably joined via a fastening means penetrating through the first support member and the second support member, and are separable within the range of a long hole formed in the second support member; friction force generating means for generating a friction force corresponding to a relative displacement between the first support member and the second support member is provided; the friction force generating means includes an interposed member having a central hole interposed between the first support member and the second support member and through which the fastening means penetrates; an impact absorbing member is provided on a part of a contact surface of the first support member or the second support member with the interposed member; a structure in which the friction force is generated between the first support member, the second support member, and the interposed member by clamping the first support member and the second support member with a predetermined clamping force via the fastening means. A bridge fall prevention device characterized by this.

2. a first support member for attachment to one of an upper structure or a lower structure; a second support member provided opposite to the first support member for attachment to the other of the lower structure or the upper structure, and the first support member and the second support member are slidably joined via a fastening means penetrating through the first support member and the second support member, and are separable within the range of a long hole formed in the second support member; friction force generating means for generating a friction force corresponding to a relative displacement between the first support member and the second support member is provided; an impact absorbing member is provided on an attachment surface of at least one of the first support member and the second support member with the upper structure or the lower structure. A bridge fall prevention device characterized by this.

3. The friction force generating means is configured such that friction force enhancing means is provided on a sliding surface of the first support member and the second support member. The bridge fall prevention device according to claim 2, characterized by this.

4. The friction force generating means is configured such that the friction force is generated between the first support member and the second support member by clamping the first support member and the second support member with a predetermined clamping force. The bridge fall prevention device according to claim 2, characterized by this.

5. ​ ​ ​ The frictional force generating means includes an interposed member having a central hole interposed between the first support member and the second support member and through which the fastening means passes. The bridge-falling prevention device according to claim 2, characterized in that by sandwiching the first support member and the second support member with a predetermined clamping force via the fastening means, a frictional force is generated between the first support member, the second support member, and the interposed member.

6. A plurality of the interposed members The bridge-falling prevention device according to claim 1 or claim 5, characterized in that they are arranged in series or arranged side by side with a predetermined interval in the longitudinal direction of the first support member and the second support member.

7. The first support member has a base plate and side plates provided in the longitudinal direction at intervals in the width direction perpendicular to the base plate. The second support member includes a central plate provided in the longitudinal direction between the side plates, an end plate provided at an end of the central plate, and the shock-absorbing member provided on the end plate. The bridge-falling prevention device according to claim 1 or claim 2, characterized in that the central plate penetrates the side plates and the holes of the fastening means penetrating the central plate are formed as elongated holes in the longitudinal direction.

8. A plurality of the central plates are provided side by side in the width direction and are provided at positions between the side plates. The bridge-falling prevention device according to claim 7, which cites claim 1, characterized in that the interposed member is disposed between the central plate and the side plate.

9. The bridge-falling prevention device according to any one of claims 1 to 8, characterized in that the frictional force generation range of the frictional force generating means is larger than the displacement range of the first support member and the second support member.

10. The frictional force generating means includes a first metal surface formed of a metal material different from that of the first support member provided on the sliding surface of the first support member, and a second metal surface formed of a metal material different from that of the second support member provided on the sliding surface of the second support member. The bridge-falling prevention device according to any one of claims 1 to 9, characterized in that the first metal surface and the second metal surface are formed of metal-based sliding materials made of metal materials having different component compositions. ​

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