JP2021067078A - Bridge fall prevention structure - Google Patents

Abstract

To provide a bridge fall prevention structure that can prevent a girder from falling off by using the upper surface side of the girder without deteriorating the original performance of the bridge.SOLUTION: A bridge fall prevention structure of a bridge 1 for preventing the falling off of an adjustment girder 2 whose end is installed at a girder receiving part 33 of adjacent viaducts 3, 3 includes: a beam member 4 installed on an upper surface 21 of the adjustment girder 2 and having an overhang part 42 projecting from an end edge 22 of the adjustment girder 2 in a bridge axial direction Y; and an anchor member 5 for attaching the beam member 4 to the adjustment girder 2 without restraining the expansion and contraction of the beam member 4 in the longitudinal direction. A plurality of beam members 4 is provided at intervals in the direction orthogonal to the bridge axis of the adjustment girder 2, and a plurality of anchor members 5 is provided at intervals in the longitudinal direction of the beam members 4.SELECTED DRAWING: Figure 1

Description

The present invention relates to a bridge collapse prevention structure for preventing a girder such as a bridge girder having an end installed on an upper portion of an adjacent structure such as a pier, a bridge, or a viaduct from falling off.

As disclosed in Patent Document 1, a structure is known that prevents the bridge collapse of the bridge girder due to the shaking of an earthquake. Specifically, by connecting the upper side surface of the pier and the lower surface side of the bridge girder with a bridge collapse prevention device composed of a belt bent by a deflection bracket, it is possible to prevent the bridge collapse even if the bridge girder moves significantly laterally. It has a structure.

Japanese Unexamined Patent Publication No. 2016-23534

However, there are cases where a new bridge collapse prevention device or the like cannot be installed in the space under the girder of a bridge such as a viaduct because the intersecting roads pass through it or a store is set up and effectively used.

Therefore, an object of the present invention is to provide a bridge collapse prevention structure for a bridge that does not deteriorate the original performance of the bridge and can prevent the girder from falling off by using the upper surface side of the girder. It is said.

In order to achieve the above object, the bridge fall prevention structure of the present invention is a bridge fall prevention structure for preventing a girder having an end installed on the upper part of an adjacent structure from falling off, and the girder. A beam member installed on the upper surface of the portion and partially projecting from the edge of the girder portion in the bridge axial direction, and the beam member attached to the girder portion without restraining expansion and contraction in the longitudinal direction of the beam member. A plurality of the beam members are provided at intervals in the direction perpendicular to the bridge axis of the girder, and a plurality of the connecting members are provided at intervals in the longitudinal direction of the beam members. It is a feature.

Here, it is preferable that the overhanging portion of the beam member overhanging from the edge of the girder portion is placed in a state in which movement in the horizontal plane is not restricted. Further, the connecting member may be arranged so as to straddle the beam member, and the end portions on both sides may be inserted into the inside of the girder portion.

Further, the beam member may be formed longer than the girder portion and may be configured to project from both end edges of the girder portion in the bridge axis direction. On the other hand, the beam member may be configured such that separate bodies are projected from the edge portions on both sides of the girder portion in the bridge axis direction.

In the bridge collapse prevention structure of the bridge of the present invention configured in this way, a part of the beam member installed on the upper surface of the girder and attached to the girder by the connecting member is projected from the edge in the bridge axial direction. There is. Further, this beam member is attached to the girder portion without being restricted from expanding and contracting in the longitudinal direction.

With such a beam member mounting structure, even if the beam member expands and contracts, the force is not transmitted to the girder portion, so that it is possible to prevent the original performance of the bridge from deteriorating. Further, since the upper surface side of the girder portion is used, it is possible to prevent the girder portion from falling off even when the space under the girder is used.

Here, if the overhanging portion of the beam member is placed in a state where the movement in the horizontal plane is not restricted, even if a force in the direction intersecting the bridge axis acts on the beam member during an earthquake, the structure adjacent to the beam member is caused by the force acting on the beam member. It is possible to prevent damage to the body and the girder itself.

Further, by arranging the connecting member across the beam member so that the ends on both sides are inserted into the girder portion, the beam member can be easily fixed to the girder portion. Become. In particular, if the end portion of the connecting material is fixed with a post-construction anchor, the construction can be performed only from the upper surface side of the girder portion.

Further, by using the beam member formed longer than the girder portion, a part of the beam member can be easily projected from the end edges on both sides of the girder portion. On the other hand, if a separate beam member is projected from the edge on both sides of the girder, it is possible to omit the installation of the beam member at the center of the girder, and the material cost can be reduced. ..

It is a vertical cross-sectional view for demonstrating the structure of the bridge collapse prevention structure of the bridge of this embodiment. It is sectional drawing for demonstrating the structure of the bridge collapse prevention structure of the bridge of this embodiment. It is explanatory drawing which showed the situation that the edge of an adjustment girder comes off from a girder receiving part at the time of an earthquake. It is explanatory drawing which showed typically the bending moment distribution which occurs when both sides of an adjustment girder are supported only by a beam member. It is explanatory drawing which showed typically the range of the shearing force acting on the adjustment girder by attaching a beam member. It is explanatory drawing which illustrated the specific structure of the beam member. It is a top view explaining the arrangement example of a beam member and an anchor material. It is a vertical sectional view for demonstrating the structure of the bridge collapse prevention structure of the bridge of Example 1. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a vertical cross-sectional view showing the bridge axis direction Y as the left-right direction on the paper surface in order to explain the configuration of the bridge collapse prevention structure of the bridge according to the present embodiment. Further, FIG. 2 is a cross-sectional view showing the bridge axis orthogonal direction X as the left-right direction on the paper surface.

Some bridges are composed of substructures such as abutments and piers and superstructures such as bridge girders. Further, as a bridge, a viaduct such as a rigid frame viaduct or a wall viaduct is known. The bridge collapse prevention structure of the bridge of the present embodiment is applied to a bridge having a girder portion in which an end portion is installed at an upper portion of a structure such as a substructure or a viaduct.

The bridge 1 illustrated in FIG. 1 shows a configuration in which an adjusting girder 2 serving as a girder is bridged between the viaducts 3 and 3 arranged at intervals in the bridge axis direction Y. The viaduct 3 has a rigid frame structure in which the end portion of the slab portion 31 and the upper end portion of the column portion 32 are rigidly joined.

A girder receiving portion 33 is provided on the upper portion of the side surface of the pillar portion 32 of the viaduct 3 orthogonal to the bridge axis direction Y. On the side surfaces of the column portions 32, 32 of the viaducts 3, 3 facing each other in the bridge axis direction Y, girder receiving portions 33, 33 are provided at the same height position, respectively.

Then, the end edges 22 and 22 of the adjusting girder 2 in the bridge axis direction Y are mounted on the pair of girder receiving portions 33 and 33 facing each other. At least one end edge 22 of the adjusting girder 2 is placed in a state where the displacement in the bridge axis direction Y is not constrained with respect to the bearing (not shown) of the girder receiving portion 33.

FIG. 1 schematically shows a state in which there is a gap between the upper surface 21 of the adjusting girder 2 and the upper surface 311 of the viaduct 3. Further, the upper surface 311 of the viaduct 3 is arranged adjacent to the edge 22 of the adjusting girder 2.

The adjusting girder 2 includes, for example, as illustrated in FIG. 2, a main beam portion 25, 25 provided at intervals in the direction X orthogonal to the bridge axis, a central floor slab portion 23 connecting the main beam portions 25, 25, and the central floor slab portion 23. It includes overhanging floor slabs 24 and 24 that project from the main beams 25 and 25 in the direction X orthogonal to the bridge axis, respectively. Such an adjusting girder 2 is manufactured of reinforced concrete (RC), prestressed concrete (PC), PRC (Prestressed Reinforced Concrete), steel material, or the like.

When the bridge 1 is a railway bridge, a track R extending in the bridge axis direction Y is laid on the upper surface 21 of the adjusting girder 2. The bridge collapse prevention structure of the bridge of the present embodiment is provided on the upper surface 21 of the adjusting girder 2 at a position that does not hinder the track R, the traveling railroad vehicle, or the like.

The bridge collapse prevention structure of the bridge of the present embodiment serves as a connecting member for attaching the beam member 4 to the adjusting girder 2 and the beam member 4 extending in the bridge axial direction Y and installed on the upper surface 21 of the adjusting girder 2. It includes an anchor material 5. In the beam member 4, a girder side portion 41 mounted on the upper surface 21 of the adjusting girder 2 and an overhanging portion 42 projecting from the end edge 22 toward the upper surface 311 of the viaduct 3 are integrally formed in a long shape. To.

The beam member 4 can be formed of, for example, a shaped steel such as an H-shaped steel or an I-shaped steel, or a steel material such as a rail or a steel frame. A plurality of beam members 4 are installed on the upper surface 21 of the adjusting girder 2 at intervals in the direction X orthogonal to the bridge axis. For example, as shown in FIG. 2, the beam members 4 and 4 are located on the overhanging floor slabs 24 and 24 symmetrical with respect to the line (bridge axis) passing through the center of the adjustment girder 2 in the direction X orthogonal to the bridge axis. 4 is arranged.

Further, the beam member 4 is attached to the adjusting girder 2 to which expansion and contraction and displacement are allowed without applying an extra force. That is, with respect to the adjusting girder 2, a plurality of anchor members 5 provided at intervals in the longitudinal direction of the girder side portion 41 of the beam member 4 so as not to restrain the expansion and contraction of the beam member 4 in the longitudinal direction. Installation is done.

The anchor member 5 is arranged so as to straddle the beam member 4, and the ends 51 and 51 on both sides are inserted into the adjusting girder 2. For example, an anchor material 5 formed into a front-view horseshoe shape (inverted U-shape) by a deformed reinforcing bar or a steel rod is put on the beam member 4, and the ends 51 and 51 are embedded inside the overhanging floor slab 24. After injecting organic adhesive or cement-based solidifying material, fix it with a construction anchor. The method of fixing the end portion 51 is not limited to this, and for example, the end portion 51 is inserted from the lower surface of the overhanging floor slab portion 24 until the tip of the end portion 51 protrudes into a steel plate applied to the lower surface of the floor slab. The tip may be joined and fixed.

A slight gap is provided between the anchor member 5 and the beam member 4, or even if they are in contact with each other, they are in close contact with each other in a pressed state so as to prevent expansion and contraction in the longitudinal direction due to a temperature change of the beam member 4. Make the mounting relationship so that it does not become.

On the other hand, on the upper surface 311 of the viaduct 3, the overhanging portion 42 of the beam member 4 is placed in a state where the movement in the horizontal plane is not restricted. For example, the overhanging portion 42 is placed only on the upper surface 311 of the slab portion 31 of the viaduct 3, and no fixing is performed.

FIG. 3 is a schematic view for explaining a situation in which the edge 22 of the adjusting girder 2 comes off from the girder receiving portion 33 of the adjacent viaduct 3 at the time of an earthquake. When a large earthquake occurs and the bridge 1 and the viaduct 3 are shaken greatly, the girder receiving portion 33 and the end edge 22 of the adjusting girder 2 just placed therein may show a movement of separating from each other.

That is, since the edge 22 of the adjusting girder 2 is not connected to the girder receiving portion 33, if the viaduct 3 and the adjusting girder 2 behave differently due to a large-scale earthquake, the range on the girder receiving portion 33 is exceeded. The edge 22 may move relatively to the position, and the adjusting girder 2 may come off from the girder receiving portion 33.

At this time, if no measures are taken to prevent the collapse of the bridge, the adjusting girder 2 will fall off and the bridge 1 will be in a state of collapse. On the other hand, if the overhanging portion 42 projects from the edge 22 of the adjusting girder 2 in the bridge axis direction Y and is placed on the upper surface 311 of the viaduct 3, the edge 22 of the adjusting girder 2 receives the girder. Even if it goes out of the range of the part 33, the bridge collapse can be prevented.

In the bridge collapse prevention structure of the bridge of the present embodiment, if even a part of the beam member 4 is caught on the upper surface 311 of the viaduct 3, the bridge collapse can be prevented. On the other hand, as shown in FIG. 4, it is considered that the maximum stress is generated in the beam member 4 when the beam members 4 and 4 on both sides of the adjusting girder 2 are in a suspended support state.

That is, FIG. 4 shows a state in which both sides of the adjusting girder 2 are supported only by the beam members 4 and 4, and all the loads acting on the adjusting girder 2 are received by the beam members 4 and 4 on both sides. On the left side of FIG. 4, the bending moment distribution M generated in the beam member 4 at this time is schematically shown.

Since it can be assumed that the beam member 4 is in a state of a cantilever whose end is fixed to the adjusting girder 2 by a plurality of anchor members 5, it is considered that the bending is maximized at the position of the anchor member 5 closest to the viaduct 3. ..

Therefore, the specific configuration of the bridge collapse prevention structure of the bridge of the present embodiment will be verified. For example, an adjustment girder 2 having a length L1 in the bridge axis direction Y of 20 m (see FIG. 7) and a width L3 in the bridge axis orthogonal direction X of 11 m and a weight of about 5700 kN (8500 kN including the influence of impact) is provided at the edge 22. A case of being supported by a total of four beam members 4 arranged on both sides of the bridge axis orthogonal direction X will be verified.

First, the bending of the beam member 4 and the check of the shearing force are performed at the position where the maximum bending moment acts (see FIG. 4). Here, it is assumed that the arm length (distance between the outermost anchor member 5 and the upper surface 311 of the viaduct 3) of the cantilever-shaped beam member 4 is 1 m.

As shown in FIG. 6, the beam member 4 uses H-shaped steel in which the parallel upper flange 431 and the lower flange 433 are connected by the web 432, and resists bending in the entire cross section. The web 432 shall resist shearing. As a result of the verification, it was verified that the H-section steel used as the beam member 4 should have a cross-sectional shape having a beam height B2 of 900 mm or more and a width B1 of 300 mm or more.

In order to suppress the beam height B2 of the H-shaped steel, the number of beam members 4 arranged in one adjusting girder 2 may be increased. For example, in the above verification, the number of beam members 4 arranged on one end edge 22 is set to 2, but by dispersing the number of beam members 4 to 3 or more, the load per beam is reduced and the beam height B2 is suppressed. You will be able to do it.

Subsequently, the bending shear force of the overhanging floor slab 24 is checked. As shown in FIG. 5, when the beam member 4 is attached to the overhanging floor slab 24, it must be able to resist the load acting through the beam member 4 by the shear strength of the resistance shearing surface 241. Here, the thickness D1 of the base of the overhanging floor slab 24 is 300 mm, the overhang amount D2 is 1050 mm, and the distance D3 between the base of the overhanging floor slab 24 and the beam member 4 is 300 mm (see FIG. 6). ..

In order to increase the area of the resistance shear surface 241 and increase the shear strength, the length L2 (see FIG. 7) of the girder side portion 41 of the beam member 4 may be lengthened. The length of the girder side portion 41 calculated by checking the bending shear force was 9 m or more. If the beam member 4 can be installed on the main beam portion 25, the required length of the girder side portion 41 can be significantly shortened.

Subsequently, the anchor material 5 for attaching the beam member 4 having the girder side portion 41 having a length of 9 m or more to the adjusting girder 2 is verified. Here, if the rigidity of the beam member 4 is high, it can be assumed that the load acts evenly on the plurality of anchor members 5.

As the anchor material 5, a deformed reinforcing bar having a reinforcing bar diameter D13 is used, and the effective embedding length is 170 mm. Designed per end 51 of the anchor material 5 in consideration of reduction of proximity arrangement Assuming that the axial tensile strength is 40 kN, it is necessary to arrange the anchor material 5 in 27 rows or more (pitch is about 330 mm) with respect to the girder side 41 of 9 m. The result was that there was. If the anchor materials 5 are arranged densely, the tensile proof stress will be lowered, and the design should be made in consideration of this point.

FIG. 7 is a plan view illustrating an arrangement example of the beam member 4 and the anchor member 5 reflecting the result of the inspection. The beam members 4 arranged at the four corners of the adjusting girder 2 having a length L1 of 20 m and a width L3 of 11 m have a length L2 of the girder side 41 of 9 m, and the pitch of the anchor material 5 for attaching them is about. It should be 330 mm. In short, the arrangement of the beam member can be omitted at the central portion of the adjusting girder 2.

Next, a method of constructing a bridge collapse prevention structure for the bridge of the present embodiment will be described.
This bridge collapse prevention structure can be provided on both the new bridge and the existing bridge 1. In this embodiment, a bridge collapse prevention structure provided to prevent the adjusting girder 2 of the existing bridge 1 from falling off will be described.

Further, in the bridge 1 provided with the bridge collapse prevention structure of the bridge of the present embodiment, an intersecting road may pass through the space below the slab portion 31 of the adjusting girder 2 and the viaduct 3, or a building such as a store may be provided. It can be applied even if it is effectively used.

First, the number of beam members 4 required for the design is conveyed to one adjusting girder 2 through the upper surfaces 311, 21 of the bridge 1. The installation location of the beam member 4 is not limited to the overhanging floor slab 24, and may be any place such as on the central floor slab 23 that does not interfere with the service of the bridge 1.

Further, the material, standard, length, etc. of the beam member 4 are obtained in advance by design or the like as described above. The length of the girder side portion 41 is determined based on the verification result of the bending shear force of the overhanging floor slab portion 24, but the length of the overhanging portion 42 is determined by the expected edge of the adjusting girder 2. The maximum distance between 22 and the upper surface 311 of the viaduct 3 can be set to a length obtained by adding an extra length sufficient to secure catching.

The beam member 4 conveyed to the top of the adjusting girder 2 is arranged at a position determined by design, such as the upper surface 21 of the overhanging floor slab 24, in a direction parallel to the bridge axis direction Y. At this time, the length corresponding to the girder side portion 41 of the beam member 4 is installed on the upper surface 21 of the overhanging floor slab portion 24, and the overhanging portion 42 is installed on the upper surface 311 of the viaduct 3. This completes the installation work for the overhanging portion 42 of the beam member 4.

On the other hand, with respect to the girder side portion 41 of the beam member 4, the anchor material 5 to be the post-construction anchor is arranged according to the pitch determined by the design. The anchor material 5 formed into a U shape by bending is put on the beam member 4 from above with the ends 51 and 51 facing downward. Then, the end portions 51, 51 of the anchor material 5 are inserted into holes drilled in the upper surfaces 21 on both sides of the beam member 4, and the organic adhesive is injected into the gap between the holes and the end portions 51.

A number of anchor members 5 determined by design is installed on one girder side portion 41. Such installation work of the beam member 4 and connection work by the anchor material 5 are carried out at the four corners of the adjusting girder 2, respectively.

Next, the operation of the bridge collapse prevention structure of the bridge of the present embodiment will be described.
In the bridge collapse prevention structure of the bridge of the present embodiment configured as described above, a part of the beam member 4 installed on the upper surface 21 of the adjusting girder 2 and attached to the adjusting girder 2 by the anchor member 5 is formed in the bridge axial direction Y. Overhangs from the edge 22 of the. Further, the beam member 4 is attached to the adjusting girder 2 without being restricted from expanding and contracting in the longitudinal direction.

With such a mounting structure of the beam member 4, even if the beam member 4 expands and contracts due to a temperature change or the like, the force is not transmitted to the adjusting girder 2, so that a force that was not planned at the time of design is applied to the adjusting girder. It is possible to prevent the original performance of the bridge 1 from being deteriorated by acting on the bridge 1.

In addition, since the upper surface 21 side of the adjustment girder 2 is used, even if a store or the like is built and used in the space under the girder, the adjustment girder 2 is prevented from falling off without being removed or repaired. You will be able to do it. In short, the bridge collapse prevention structure can be constructed while the space below the existing bridge 1 is still in service.

Further, since the overhanging portion 42 of the beam member 4 is placed on the upper surface 311 of the adjacent viaduct 3 in a state where the movement in the horizontal plane is not restricted, the force in the direction intersecting the bridge axis during an earthquake is applied to the beam member 4 and the beam member 4. Even if it acts on the adjusting girder 2, the force is not transmitted to the viaduct 3 via the beam member 4, and the viaduct 3 and the adjusting girder 2 are prevented from being damaged due to the installation of the beam member 4. Can be done.

Further, by arranging the anchor member 5 across the beam member 4 so that the end portions 51, 51 on both sides are inserted into the adjusting girder 2, the beam member 4 can be easily relative to the adjusting girder 2. Can be fixed. In particular, if the end portion 51 of the anchor material 5 is fixed by the post-construction anchor, the bridge collapse prevention structure can be constructed only by the work from the upper surface 21 side of the adjusting girder 2.

Further, when the fixing force by the adhesive is insufficient, the end portion 51 of the anchor material 5 is penetrated, and a steel plate, a nut, or the like is fixed to the end portion 51 protruding toward the lower surface side of the adjusting girder 2. It becomes possible to secure high fixing power.

Further, if the beam members 4 and 4 which are separate bodies are projected from the end edges 22 and 22 on both sides of the adjusting girder 2, the installation can be omitted at the center of the adjusting girder 2 and the material cost is reduced. It can be reduced.

By providing the existing bridge 1 with a bridge collapse prevention structure afterwards in this way, it is possible to prevent the adjusting girder 2 from falling off and minimize the functional deterioration of the bridge 1 due to the earthquake. That is, in the bridge 1, if the adjusting girder 2 falls off from the girder receiving portion 33 and a step is generated between the upper surface 311 of the viaduct 3 and the upper surface 21 of the adjusting girder 2, if it is a road bridge, it becomes an obstacle for automobiles to pass. Or, if it is a railway bridge, the rails may be deformed, which may eventually cut off the transportation network. On the other hand, by providing the bridge collapse prevention structure of the bridge of the present embodiment, even if an unexpected large-scale earthquake occurs, the lifeline can be maintained and contribute to early recovery.

Hereinafter, a bridge collapse prevention structure of a bridge having a form different from that of the above-described embodiment will be described with reference to FIG. The same or equivalent parts as those described in the above-described embodiment will be described using the same terms or the same reference numerals.

The bridge collapse prevention structure of the bridge of the first embodiment is applied to the bridge 1A having a relatively short girder portion. In the bridge 1A shown in FIG. 8, for example, the length of the adjusting girder 2A, which is the girder portion bridged between the viaducts 3 and 3, in the bridge axis direction Y is about 10 m.

The bridge collapse prevention structure of the bridge of the first embodiment is a connecting member for attaching the beam member 4A to the adjusting girder 2A and the beam member 4A extending in the bridge axial direction Y and installed on the upper surface 21 of the adjusting girder 2A. It includes an anchor material 5.

The beam member 4A is projected from the girder side portion 41A mounted on the upper surface 21 of the adjusting girder 2A and the upper surfaces 311, 311 of the adjacent viaducts 3 and 3 from the end edges 22 and 22 on both sides, respectively. The portions 42A and 42A are integrally formed in a long shape.

In short, the girder side portion 41A of the beam member 4A of the first embodiment has a length in the bridge axial direction Y approximately the same as the length of the adjusting girder 2A, and projects from both ends of the girder side portion 41 in the bridge axial direction Y. It is possible to prevent the adjusting girder 2A from falling off by catching the overhanging portions 42A and 42A.

In the case of the bridge collapse prevention structure of the bridge of the first embodiment configured in this way, by using the beam member 4A formed longer than the adjusting girder 2A, it is easy to start from the end edges 22 and 22 on both sides of the adjusting girder 2A. The overhanging portions 42A and 42A, which are a part of the beam member 4A, can be overhanging.
Since other configurations and actions and effects are substantially the same as those of the above-described embodiment, description thereof will be omitted.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to the embodiments and examples, and design changes are made to the extent that the gist of the present invention is not deviated. Is included in the present invention.

For example, bridges 1 and 1A provided with viaducts 3 and 3 as adjacent structures described in the above-described embodiment and the first embodiment are examples, and the present invention is not limited to these, such as bridge piers, piers, and bridge girders. The present invention can be applied to a bridge having another form of substructure or superstructure.

Further, in the above-described embodiment and the first embodiment, the case where the existing bridges 1 and 1A are reinforced has been described, but the present invention is not limited to this, and the bridge collapse prevention structure of the present invention is simultaneously applied when constructing a new bridge. It can also be provided.

Further, the number, cross-sectional shape, and required length of the beam members 4 and 4A arranged on the one adjusting girder 2 described in the above-described embodiment and the first embodiment are examples, and the present invention is not limited thereto. However, the number of beam members to be arranged can be arbitrarily set according to the space where the upper surface of the girder can be installed. Further, the structure may be such that only a part of the beam member is projected from one end edge of the girder portion.

1: Bridge 2: Adjustment girder (girder part)
21: Top surface 22: Edge edge 3: Viaduct (adjacent structure)
33: Girder receiving part (upper part)
4: Beam member 41: Girder side 42: Overhang 5: Anchor material (connecting material)
51: End 1A: Bridge 2A: Adjustment girder 4A: Beam member 41A: Girder side 42A: Overhang X: Bridge axis orthogonal direction Y: Bridge axis direction

Claims (5)

It is a bridge collapse prevention structure for bridges to prevent the girders whose ends are installed on the upper part of the adjacent structure from falling off.
A beam member installed on the upper surface of the girder and partially projecting from the edge of the girder in the bridge axis direction.
A connecting member for attaching the beam member to the girder without restraining the expansion and contraction of the beam member in the longitudinal direction is provided.
A bridge collapse prevention structure for a bridge, characterized in that a plurality of the beam members are provided at intervals in the direction orthogonal to the bridge axis of the girder, and a plurality of the connecting members are provided at intervals in the longitudinal direction of the beam members. .. The bridge collapse prevention structure for a bridge according to claim 1, wherein the overhanging portion of the beam member overhanging from the edge of the girder portion is placed in a state in which movement in a horizontal plane is not restricted. .. The bridge collapse prevention structure for a bridge according to claim 1 or 2, wherein the connecting member is arranged so as to straddle the beam member and both end portions are inserted inside the girder portion. The invention according to any one of claims 1 to 3, wherein the beam member is formed longer than the girder portion and projects from both end edges of the girder portion in the bridge axis direction. Bridge collapse prevention structure. The bridge collapse prevention structure for a bridge according to any one of claims 1 to 3, wherein separate bodies of the beam member project from both end edges of the girder portion in the bridge axial direction. ..

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