JP4468212B2 - Fall bridge prevention device - Google Patents

Description

  The present invention relates to an apparatus for preventing a bridge provided on a road or a railroad from falling, and more particularly to an apparatus for preventing a bridge from falling from a bridge as a support portion when an earthquake occurs.

Normally, when bridges such as road bridges and railway bridges are subjected to a large horizontal force on their piers and abutments due to earthquakes, etc., not only bridge supports such as piers and abutments are damaged, but they also vibrate and the bridge girder becomes abutment. It will cause the damage of falling from or falling over. As a bridge prevention device for preventing such a bridge girder from dropping, an apparatus in which a bridge girder on the abutment or a bridge girder and the abutment are coupled by a chain, a cable, a steel rod, or the like is used.
JP 2002-97607 A JP 2004-36337 A

  None of the conventional fallen bridge prevention devices, including those described above, has a problem that the appearance is impaired when attached to a bridge because the appearance is not smart.

  In addition, the conventional bridge protection device is designed to expand and contract at all times to absorb the displacement, and to exert a function to prevent the bridge from falling in the event of a large earthquake. Therefore, rubber is used as a cushioning material to absorb the impact during an earthquake. Although it is often used, since the falling bridge prevention device installed between the bridge girders or between the abutment and the bridge girders cannot take a large diameter, the rubber as the cushioning material has a small area and its cushioning effect is small. Moreover, although it has a function to prevent a fallen bridge at the time of the L2 earthquake, there is no one provided with a displacement limiting structure at the time of the L1 earthquake.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a falling bridge prevention device capable of a compact design that does not impair the beauty of the bridge, and with a compact structure. The present invention is to provide a fallen bridge prevention device having a large buffering effect and having a displacement limiting structure at the time of the L1 earthquake.

  The falling bridge prevention device according to the first aspect of the present invention is a falling bridge prevention device stretched between a bracket attached to the bridge girder and a bracket attached to the bridge girder or an adjacent bridge girder. And a movable side member and a fixed side member attached to both ends thereof, and these members attach a clevis to one end of a pipe and connect the clevis to a bracket via a cross joint. In addition, a sleeve for connecting a long member to the other end of the pipe is attached. In the movable side member, the end of the long member is inserted into the sleeve in a stretchable state against the spring force. In the fixed side member, the end of the long member is fixed to the sleeve.

According to a second aspect of the present invention, there is provided the fallen bridge preventing device according to the first aspect, wherein the end of the long member inserted through the sleeve protrudes from the sleeve in the pipe in the movable side member. A stopper is fixed to the tip of the protruding portion, an intermediate ring is loosely fitted to the sleeve side via a buffer rubber, and a holding member is loosely fitted to the stopper side. The intermediate ring and the holding member The coil spring which surrounds a long member is arrange | positioned between these.

According to a third aspect of the present invention, there is provided the fallen bridge prevention device according to the first aspect, wherein the end of the long member inserted through the sleeve projects from the sleeve in the pipe in the movable side member. A stopper is fixed to the tip of the protruding portion, an intermediate ring is loosely fitted on the sleeve side via a cylindrical wedge, and a holding member is loosely fitted on the stopper side. A coil spring that surrounds the long member is disposed between the holding members, and an enlarged portion for inserting a wedge is formed on the inner diameter side of the sleeve, and a tapered surface is formed at the bottom of the enlarged portion. The taper surface is characterized by matching with the taper formed near the tip of the wedge .

According to a fourth aspect of the present invention, there is provided the fallen bridge prevention device according to the first aspect, wherein the end of the long member inserted through the sleeve protrudes from the sleeve in the pipe in the movable side member. A stopper is fixed to the tip of the protruding portion, an intermediate ring is loosely fitted to the sleeve side via a stopper pipe, and a stopper member is loosely fitted to the stopper side. The intermediate ring and the stopper member A coil spring that surrounds the long member is disposed between them, and in the stopper pipe, a cylindrical wedge is disposed so as to surround the long member, and a wedge is provided on the inner diameter side of the sleeve. An enlarged portion for insertion is formed, and a tapered surface is formed at the bottom of the enlarged portion, and this tapered surface matches the taper formed near the tip of the wedge, Ring A is provided around the lip portion overlapping the end face in the axial direction of the stopper pipe is formed notch in the base portion of the lip portion, the stopper pipe is in contact with the lip portion of the intermediate ring It is characterized by that.

  The fallen bridge prevention device according to the first aspect of the present invention uses a pipe for the movable side member and the fixed side member that are attached to both ends of the long member for connection, so that various functions such as an expansion / contraction function are provided. It can be housed in the structure, so that the structure to perform these functions can be protected from rust and damage, and at the same time, the combination of clevis and cruciform joint enables a compact design of a joint that can move in all directions. Therefore, the configuration of the entire apparatus becomes compact.

According to a second aspect of the present invention, there is provided the fallen bridge preventing device according to the first aspect, wherein the end of the long member inserted through the sleeve protrudes from the sleeve in the pipe in the movable side member. A stopper is fixed to the tip of the protruding portion, an intermediate ring is loosely fitted to the sleeve side via a buffer rubber, and a holding member is loosely fitted to the stopper side. The intermediate ring and the holding member In addition to the above effects, a shock is absorbed by the compression deformation of the coil springs and the elastic action of the shock absorbing rubber, and a large shock absorbing effect is obtained. There is an effect that can be demonstrated.

According to a third aspect of the present invention, there is provided the fallen bridge prevention device according to the first aspect, wherein the end of the long member inserted through the sleeve projects from the sleeve in the pipe in the movable side member. A stopper is fixed to the tip of the protruding portion, an intermediate ring is loosely fitted on the sleeve side via a cylindrical wedge, and a holding member is loosely fitted on the stopper side. A coil spring that surrounds the long member is disposed between the holding members, and an enlarged portion for inserting a wedge is formed on the inner diameter side of the sleeve, and a tapered surface is formed at the bottom of the enlarged portion. and, since the tapered surface is characterized in that meets the taper formed in the vicinity of the tip of the wedge, in addition to the above effects, while from beyond the live loads up to the girder, energy It is absorbed, an effect that can be exhibited significant buffering effect.

According to a fourth aspect of the present invention, there is provided the fallen bridge prevention device according to the first aspect, wherein the end of the long member inserted through the sleeve protrudes from the sleeve in the pipe in the movable side member. A stopper is fixed to the tip of the protruding portion, an intermediate ring is loosely fitted to the sleeve side via a stopper pipe, and a stopper member is loosely fitted to the stopper side. The intermediate ring and the stopper member A coil spring that surrounds the long member is disposed between them, and in the stopper pipe, a cylindrical wedge is disposed so as to surround the long member, and a wedge is provided on the inner diameter side of the sleeve. An enlarged portion for insertion is formed, and a tapered surface is formed at the bottom of the enlarged portion, and this tapered surface matches the taper formed near the tip of the wedge, Ring A is provided around the lip portion overlapping the end face in the axial direction of the stopper pipe is formed notch in the base portion of the lip portion, the stopper pipe is in contact with the lip portion of the intermediate ring Therefore, in addition to the above effect, energy is absorbed from the time when the breaking load determined by the displacement limiting structure is exceeded to the falling bridge, and there is an effect that a large buffering effect can be exhibited.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an explanatory view showing a bridge to which a falling bridge prevention device of the present invention is applied, FIG. 2 is a sectional view showing a fixed side member and a movable side member of the falling bridge prevention device according to the first embodiment of the present invention, and FIG. It is sectional drawing which shows a part of movable side member in 2 in an orthogonal direction.

  As shown in FIG. 1, this falling bridge prevention device is stretched between a bracket 1b attached to a bridge girder 1 and a bracket 2b attached to an abutment 2 that supports the bridge girder 1. The connecting cable 3 as a long member, a movable side member 4 and a fixed side member 5 attached to both ends thereof. In the illustrated example, the movable side member 4 is attached to the abutment 2, and the fixed side member 5 is attached to the bridge girder 1.

  As shown in FIG. 2, the connecting cable 3 used in this falling bridge prevention device is composed of a PC strand 3a and a steel apartment 3b into which both ends are inserted and fixed, and a male screw is provided at the end of the apartment 3b. The part 3c is formed. When the acting load is small, a steel rod can be used as the long member for connection. However, since the illustrated falling bridge prevention device assumes that a large load is applied, such a connection cable 3 is used. Used.

  As shown in FIGS. 2 and 3, the movable member 4 has a clevis 12 attached to one end of a steel pipe 11 by welding, and the clevis 12 is connected to the bracket 2 b via a cross joint 13. . Here, the cross joint 13 is made of weldable cast steel. For this reason, since the cross-shaped perforated plates 13a and 13b and the round intermediate plate 13c can be formed smoothly and integrally with a corner, the force flow can be transmitted smoothly unlike the welded structure, so that the tensile strength is high. It is expensive. The clevis 12 is also made of cast steel, and the combination of the clevis 12 made of cast steel and the cross joint 13 enables a compact design of the joint that can move in all directions.

  A sleeve 14 for connecting the connecting cable 3 is screwed to the other end of the pipe 11 of the movable member 4. The connecting cable 3 is inserted into the sleeve 14, and an end protrudes from the sleeve 14 in the pipe 11, and a nut serving as a stopper 15 is screwed into the male screw portion 3 c at the tip of the connecting cable 3. And while the intermediate ring 17 is loosely fitted to the sleeve 14 side via the buffer rubber 16, and the holding member 18 is loosely fitted to the stopper 15 side, between the intermediate ring 17 and the holding member 18, A coil spring 19 surrounding the condominium 3b of the connecting cable 3 is disposed. Thereby, on the movable side member 4 side, the end portion of the connection cable 3 is inserted into the sleeve 14 in a state where the end portion of the connection cable 3 can be expanded and contracted against the spring force. In the figure, 11a is a drain hole.

  As shown in FIG. 2, the fixed side member 5 has a clevis 22 attached to one end of a steel pipe 21 by welding, and the clevis 22 is connected to the bracket 1 b of the bridge girder 1 through a cross joint 23. That is, the mounting structure of the fixed side member 5 to the bracket 1 b is the same as that of the movable side member 4.

  A sleeve 24 for connecting the connecting cable 3 is screwed to the other end of the pipe 21 of the stationary member 5. The connecting cable 3 is fixed by a nut 25 in a state where the male screw portion 3 c at the end is screwed into the screw hole of the sleeve 24. As a result, the end of the connecting cable 3 is fixed to the sleeve 24 on the fixed member 5 side. In the figure, 21a is a drain hole.

  FIG. 4 is a load-displacement diagram (P-δ diagram) showing the mechanical characteristics of the falling bridge prevention device including the movable side member shown in FIG. In FIG. 4, Pu represents a breaking load, Py represents a yield load, and Rd represents a dead load reaction force. In the design of the falling bridge prevention structure, a horizontal force equivalent to 1.5 times the dead load reaction force is designed so that the upper structure can be supported even under special conditions such as when the upper structure deviates. Specified as seismic force (Japan Road Association, “Road Bridge Specification / Explanation, Earthquake Resistant Design”, published in March 2002, p.237-276 “16.3 Fall Bridge Prevention Structure” reference).

  As shown in FIG. 4, when the bridge girder 1 and the abutment 2 cause a slight relative displacement during normal use in which a live load is applied, the relative displacement is accompanied by the movement of the stopper 15 and the holding member 18. Absorbed by the expansion and contraction within the elastic deformation of the coil spring 19, a large load does not act on the connecting cable 3 and the intermediate ring 17.

  However, when a large earthquake occurs and the relative displacement between the bridge girder 1 and the abutment 2 increases, the impact is absorbed by the compression deformation of the coil spring 19 and the elastic deformation of the buffer rubber 16, but the yield load Py is exceeded and the breaking load Pu is reached. In the meantime, the connecting state of the bridge girder 1 and the abutment 2 is maintained by the connecting cable 3, and the bridge girder is prevented from falling from the abutment.

FIG. 5 is a cross-sectional view showing a movable side member of the falling bridge prevention device according to the second embodiment of the present invention. FIG. 5 shows only the main portion of the movable side member, configurations other than that shown is the same as the bridge collapse preventing device shown in FIGS.

One end side of the movable side member 4, although not shown, in the same manner as shown in FIGS. 2 and 3, attached by welding clevis at one end of the steel pipe 31, via the cross joint and the clevis Are connected to the bracket 2b.

On the other hand, the other end of the pipe 31 of the movable side member 4, as shown in FIG. 5, the flanged sleeve 32 for connecting the connecting cable 3 is attached by screwing. The connecting cable 3 is inserted into the sleeve 32, and an end portion of the connecting cable 3 protrudes greatly from the sleeve 32 in the pipe 31, and a nut serving as a stopper 33 is screwed into the male screw portion 3c at the tip of the connecting cable 3. . The intermediate ring 35 is loosely fitted on the sleeve 32 side via the cylindrical wedge 34, and the holding member 36 is loosely fitted on the stopper 33 side. The coil spring 37 surrounding the condominium 3b of the connecting cable 3 is disposed. Further, an enlarged portion 32a for inserting the wedge 34 is formed on the inner diameter side of the sleeve 32, and a tapered surface 32b is formed on the bottom of the enlarged portion 32a. The tapered surface 32b is near the tip of the wedge 34. It is designed to match the taper formed.

Figure 6 is a load representing the dynamic characteristics of the bridge collapse preventing device including a movable side member shown in FIG. 5 - is a displacement diagram (P-[delta] diagram). In FIG. 6, Pu represents a breaking load, Py represents a yield load, and Rd represents a dead load reaction force.

  As shown in FIG. 6, when the bridge girder 1 and the abutment 2 cause a slight relative displacement during normal use in which a live load is applied, the relative displacement is accompanied by the movement of the stopper 33 and the holding member 36. Absorbed by the expansion and contraction in the expansion and contraction of the coil spring 37, a large load does not act on the connection cable 3 and the intermediate ring 35.

  However, when a large earthquake occurs and the relative displacement between the bridge girder 1 and the abutment 2 is increased, and the coil spring 37 is compressed and deformed, and the stopper 33 and the holding member 36 abut against the intermediate ring 35, the relative displacement further increases. become unable. In this state, when the load is further applied to the connection cable 3 and reaches the wedge pressure input, the wedge 34 pushed by the intermediate ring 35 slides on the taper surface 32 b of the sleeve 32 and enters the gap between the connection cable 3 and the sleeve 32. It will be press-fitted, and impact energy is absorbed during this press-fitting (shaded area). Then, the intermediate ring 35 is stopped in contact with the sleeve 32, and the connecting state of the bridge girder 1 and the abutment 2 is maintained by the connecting cable 3 at this stop position until the intermediate load 35 exceeds the yield load Py and reaches the breaking load Pu. The bridge girder 1 is prevented from falling from the abutment 2.

  As described above, the falling bridge prevention device according to the second embodiment incorporates an energy absorption structure that operates when the live load exceeds the movable side member 4. The damping force at the time of press-fitting can be freely set by the shape of the meshing portion between the sleeve 32 and the wedge 34.

FIG. 7 is a cross-sectional view showing a movable side member of the falling bridge prevention device according to the third embodiment of the present invention. The 7 shows only the main portion of the movable side member, configurations other than that shown is the same as the bridge collapse preventing device shown in FIGS.

One end side of the movable side member 4 is not shown, in the same manner as shown in FIG. 2 and FIG. 3, attached by welding clevis at one end of the steel pipe 41, via the cross joint and the clevis Are connected to the bracket 2b.

On the other hand, the other end of the pipe 41 of the movable side member 4, as shown in FIG. 7, the flanged sleeve 42 for connecting the connecting cable 3 is attached by screwing. The connecting cable 3 is inserted into the sleeve 42, and an end portion of the connecting cable 3 protrudes greatly from the sleeve 42 in the pipe 41. A nut serving as a stopper 43 is screwed into the male screw portion 3c at the tip of the connecting cable 3. . The intermediate ring 45 is loosely fitted to the sleeve 42 via the stopper pipe 44 and the stopper member 46 is loosely fitted to the stopper 43 side. A coil spring 47 surrounding the condominium 3b of the connecting cable 3 is disposed. Further, in the stopper pipe 44, a cylindrical wedge 48 is disposed so as to surround the connecting cable 3. An enlarged portion 42 a for inserting the wedge 48 is formed on the inner diameter side of the sleeve 42, and a tapered surface 42 b is formed on the bottom of the enlarged portion 42 a, and the tapered surface 42 b is near the tip of the wedge 48. It is designed to match the taper formed.

  As shown in a partially enlarged view of FIG. 8, the intermediate ring 45 is provided with a lip portion 45 a that overlaps the end surface of the stopper pipe 44 in the axial direction, and the lip portion 45 a of the intermediate ring 45 is provided with a stopper. The pipe 44 comes into contact. A notch 45b is formed at the base of the lip 45a. Therefore, when the intermediate ring 45 is pushed toward the sleeve 42 and a load of a certain level or more is applied to the lip portion 45a, the lip portion 45a is broken by shear. The breaking load can be set by the size of the cross-sectional area in the shear direction in consideration of the notch 45b of the lip portion 45a.

  FIG. 9 is a load-displacement diagram (P-δ diagram) showing the mechanical characteristics of the falling-bridge preventing device including the movable-side member shown in FIG. In FIG. 9, Pu represents the breaking load, Py represents the yield load, Rd represents the dead load reaction force, 3KhRd (Kh: design horizontal seismic intensity corresponding to level 1 ground motion) is the displacement limiting load, and design of the displacement limiting structure Design seismic force used for

  As shown in FIG. 9, when the bridge girder 1 and the abutment 2 are slightly displaced during normal use, this relative displacement is caused by the expansion and contraction of the coil spring 47 accompanying the movement of the stopper 43 and the stopper member 46. And a large load does not act on the connecting cable 3 and the intermediate ring 45.

  However, when the bridge girder 1 and the abutment 2 move greatly due to a large earthquake, the coil spring 47 is compressed and deformed so that the stopper 43 and the stopper member 46 abut against the intermediate ring 45 and cannot be relatively displaced. In this state, a load is further applied to the connecting cable 3, and when the load reaches a certain load, the load is lost and the lip portion 45 a of the intermediate ring 45 is sheared and broken.

  When the lip portion 45 a is sheared and broken, the intermediate ring 45 hits the wedge 48 and is pushed. As the relative displacement between the bridge girder 1 and the abutment 2 increases thereafter, a load acts on the connecting cable 3 to reach the wedge pressure input, so that the wedge 48 pushed by the intermediate ring 45 becomes the tapered surface of the sleeve 42. 42b is slid into the gap between the connecting cable 3 and the sleeve 42, and impact energy is absorbed during the press-fitting (shaded portion). Then, the intermediate ring 45 is stopped in a state where it hits the sleeve 42, and the connecting state of the bridge girder 1 and the abutment 2 is maintained by the connecting cable 3 at this stop position, and until the breaking load Pu is reached beyond the yield load Py. The bridge girder 1 is prevented from falling from the abutment 2.

  As described above, the falling bridge prevention device according to the third embodiment incorporates the movable member 4 with a displacement limiting structure and an energy absorbing structure that operate when a live load is exceeded. The displacement limiting structure can easily set the breaking load by determining the size of the cross-sectional area in the shear direction in consideration of the notch 45b of the lip portion 45a in the intermediate ring 45. Further, the damping force at the time of press-fitting can be freely set by the shape of the meshing portion between the sleeve 42 and the wedge 48.

  The embodiment of the present invention has been described in detail above. However, the fallen bridge prevention device according to the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. It is natural that it is possible.

  For example, in the above example, the clevis is attached to the pipe by welding, but similarly to the sleeve, the clevis may be threaded, the pipe may be cut, and both may be screwed together.

It is explanatory drawing which shows the bridge to which the falling bridge prevention apparatus of this invention is applied. It is sectional drawing which shows the fixed side member and movable side member of the fallen bridge prevention apparatus which concern on the 1st Embodiment of this invention. It is sectional drawing which shows a part of movable side member in FIG. 2 in an orthogonal direction. FIG. 3 is a load-displacement diagram (P-δ diagram) showing mechanical characteristics of the falling bridge prevention device including the movable side member shown in FIG. 2. It is sectional drawing which shows the movable side member of the falling bridge prevention apparatus which concerns on the 2nd form of this invention in the principal part. Load representing the dynamic characteristics of the bridge collapse preventing device including a movable side member shown in FIG. 5 - is a displacement diagram (P-[delta] diagram). It is sectional drawing which shows the movable side member of the falling bridge prevention apparatus which concerns on the 3rd form of this invention in the principal part. FIG. 8 is a partially enlarged view of FIG. 7. Load representing the dynamic characteristics of the bridge collapse preventing device including a movable side member shown in FIG. 7 - is a displacement diagram (P-[delta] diagram).

DESCRIPTION OF SYMBOLS 1 Bridge girder 1b Bracket 2 Abutment 2b Bracket 3 Connecting cable 3a PC strand 3b Mansion 3c Male screw part 4 Movable side member 5 Fixed side member 11 Pipe 11a Drain hole 12 Clevis 13 Cross joint 13a, 13b Perforated plate 13c Intermediate plate 14 Sleeve 15 Stopper 16 Buffer Rubber 17 Intermediate Ring 18 Holding Member 19 Coil Spring 21 Pipe 21a Drain Hole 22 Clevis 23 Cross Joint 24 Sleeve 25 Nut 31 Pipe 32 Sleeve 32a Enlarged Part 32b Tapered Surface 33 Stopper 34 Wedge 35 Intermediate Ring 36 Holding Member 37 Coil spring 41 Pipe 42 Stopper 43 Stopper 44 Stopper pipe 45 Intermediate ring 45a Lip part 45b Notch 46 Stopping member 47 Coil spring 48 Wedge

Claims (4)

  A falling bridge prevention device stretched between a bracket attached to a bridge girder and a bridge abutment for supporting this bridge girder or a bracket attached to an adjacent bridge girder, and is attached to a long member for connection and both ends thereof It consists of a movable side member and a fixed side member. These members attach a clevis to one end of a pipe, connect this clevis to a bracket via a cross joint, and connect a long member to the other end of the pipe. In the movable side member, the end of the long member is inserted into the sleeve in a state where it can be expanded and contracted against the spring force, and in the fixed side member, the end of the long member The fallen bridge prevention device characterized by being fixed to the sleeve. In the fallen bridge prevention device according to claim 1, in the movable side member, the end of the long member inserted through the sleeve protrudes from the sleeve in the pipe, and a stopper is fixed to the tip of the protruding portion. The intermediate ring is loosely fitted on the sleeve side via a buffer rubber, and the holding member is loosely fitted on the stopper side, and a coil spring surrounding the long member is disposed between the intermediate ring and the holding member. The fallen bridge prevention device characterized by being made. In the fallen bridge prevention device according to claim 1, in the movable side member, the end of the long member inserted through the sleeve protrudes from the sleeve in the pipe, and a stopper is fixed to the tip of the protruding portion. The intermediate ring is loosely fitted on the sleeve side via a cylindrical wedge, and the holding member is loosely fitted on the stopper side. The coil spring surrounds the long member between the intermediate ring and the holding member. An enlarged portion for inserting a wedge is formed on the inner diameter side of the sleeve, and a tapered surface is formed at the bottom of the enlarged portion, and this tapered surface is formed near the tip of the wedge. A falling bridge prevention device characterized by conforming to the taper . In the fallen bridge prevention device according to claim 1, in the movable side member, the end of the long member inserted through the sleeve protrudes from the sleeve in the pipe, and a stopper is fixed to the tip of the protruding portion. The intermediate ring is loosely fitted on the sleeve side via the stopper pipe, and the stopper member is loosely fitted on the stopper side, and a coil spring surrounding the long member is disposed between the intermediate ring and the stopper member. Furthermore, in the stopper pipe, a cylindrical wedge is arranged so as to surround the long member, and an enlarged portion for inserting the wedge is formed on the inner diameter side of the sleeve. A taper surface is formed at the bottom, and this taper surface matches the taper formed near the tip of the wedge, and the intermediate ring is axially aligned with the end surface of the stopper pipe. Lip portions mutually becomes is provided around, and a notch is formed in the base portion of the lip portion, girder prevention apparatus characterized by stopper pipe is in contact with the lip portion of the intermediate ring.

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