JP7460514B2 - Viaduct or bridge corner bend prevention device - Google Patents

Description

Article 30, Paragraph 2 of the Patent Act applies Railway Engineering Symposium Proceedings No. 24 Published on July 6, 2020

The present invention relates to a corner bending prevention device mainly used for seismic reinforcement of railway girder viaducts, bridges, etc.

On viaducts and bridges, different types of structures are installed along the bridge axis depending on the supporting ground and the traffic conditions on the ground. In such viaducts and bridges, unequal displacements such as misalignment and bent corners can occur between adjacent structures during an earthquake. For example, misalignment is likely to occur in overhanging rigid frame viaducts, while bends are likely to occur in girder viaducts and girder bridges, including Gerber rigid frame viaducts, due to the different vibration characteristics between adjacent structures. Suppressing these unequal displacements that occur during earthquakes is important to ensure the safety of train and vehicle operation.

In existing railway structures, rigid-frame viaducts are usually installed where there are no intersections such as roads, and bridge girders using rigid-frame abutments or piers are installed where there are intersections. Figure 1 shows an example of an adjustable girder rigid-frame viaduct (overbridge) structure 1 around the intersection with the road. The viaduct structure 1 has an adjustment girder 13 at the connection between the bridge girder 11 on the road and the rigid-frame viaduct 12. The bridge girder 11 is supported by rigid-frame abutments 14 at both ends in the front-rear direction of the bridge axis, and the rigid-frame abutments 14 supporting the bridge girder 11 on the road have a different structural form from the rigid-frame viaduct 12. In addition, the bridge girder 11 and the adjustment girder 13 have a large weight difference. In other words, at the intersection with the road, the structure changes from the rigid-frame viaduct 12 to the rigid-frame abutments 14, resulting in different vibration characteristics, which causes a phase difference in the response displacement during an earthquake, and as shown in Figure 1, corner bending 10, which is an angle deviation around the vertical axis, is likely to occur.

Conventional methods to prevent corner bending of existing railway structures include adjusting the vibration characteristics of adjacent structures and installing devices that physically suppress unequal displacement.

As a method for adjusting vibration properties between adjacent structures, Non-Patent Document 1 discloses a method of providing damper braces. As for a device for physically suppressing corner bending, a corner bending prevention device has been developed that connects adjacent structures in the track direction using steel members, as disclosed in Non-Patent Document 2. This is a corner bending prevention device installed on the fixed bearing side of a rigid-frame viaduct, and its effectiveness has been partially verified through experiments and numerical analysis for railway rigid-frame viaducts.

Further, Patent Document 1 discloses a corner bending prevention device that is applied to a connection location between an adjustment girder and a rigid-frame viaduct that are connected via a fixed support.

JP 2011-17192 A

Naoyuki Kita, Koji Yoshida, Motoyuki Okano, Masaki Seki: Practical application of compression damper brace method for railway RC rigid frame viaducts, Journal of the Japan Society of Civil Engineers, Vol. 63, No. 3, pp. 277-286, March 2007. Naoki Maruyama, Masamichi Sogabe, Yukihiro Tanimura, Kazuhiro Harada, Toshiyuki Kuroiwa, Ryota Kasakura: Performance Evaluation of Corner Bending Prevention Devices for Railway Viaducts, Journal of Railway Mechanics, pp.162-169, 2009

However, the method of installing dampers and braces as described in Non-Patent Document 1 requires that sufficient space be secured for installation, and places where it can be installed are limited.

In addition, the corner bending prevention device described in Non-Patent Document 2 is installed on the top surface of a cantilever slab, and there are problems with installation, such as limited installation space on ballasted tracks and difficulty in installation during the day.

The corner bending prevention device described in Patent Document 1 is only applicable to fixed supports, and in this case, although it has some effect on the entire viaduct, because it is not installed directly on the girders on the movable supports, the problem of corner bending on the movable supports becoming relatively large arises.

As described above, in either case, there is a problem that the scope of applicability is limited, and there is a demand for a corner-break prevention device that can be installed without interfering with the running of trains on the track and that can be applied to railway rigid-frame bridge abutments, etc., where corner bending is prominent.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a corner bending prevention device that has a wide range of applications in terms of installation space and workability, and can prevent corner bending of viaducts and bridges. shall be.

In order to solve the above problems, the present invention provides a corner bending prevention device that is installed across structures installed adjacent to each other in the axial direction of a viaduct or a bridge, wherein the The base plate includes two base plates arranged at opposite ends, a connecting member that connects the base plates, and an anchor bolt that fixes the base plate to the structure, and the base plate is connected to the structure without using a support member. The two structures directly adjacent to each other and the corner bending prevention device are arranged directly at the end of the structure and are arranged in series in the axial direction of the bridge.

The corner bending prevention device may include a bracket that connects the two base plates and the connecting member.

When the corner bending prevention device is installed on the movable bearing side of a viaduct or bridge, a clearance is provided that can accommodate displacement of the structure in the bridge axis direction. In this case, the clearance may be provided by making the bolt hole for the anchor bolt formed in one of the base plates a long hole in the bridge axis direction. Alternatively, the clearance may be provided by connecting the connecting member and one of the base plates with a gap in the bridge axis direction at the connecting portion.

It is preferable that the yield strength Py of the connecting member in the tensile direction satisfies the formula (1) , and the rotational strength My is obtained by a simulation in which the structure is modeled, and is the rotational strength when the amount of corner bending of the structure becomes a certain value or less . In this case, it is preferable that the rotational strength My is 4000 kN·m or more.
Py=My/2L (1)
My: Rotational strength required to prevent the structure from bending. L: Distance from the center of the structure to the bending prevention device.

When the connecting member is attached at a position 4.5 m from the center of a structure having an overpass , the horizontal resistance strength of the connecting member in the bridge axis direction is preferably 400 kN or more. In addition, the total shear resistance of the anchor bolts is preferably greater than the horizontal resistance strength of the connecting member.

Further, according to the present invention, the corner bending prevention device can be installed outside the track of a structure such as a viaduct or a bridge.

According to the present invention, it is possible to connect adjacent structures with a simple configuration, suppress the vibration of each structurally different structure with its own unique period during an earthquake, and physically suppress the relative displacement between adjacent structures. Moreover, since it can be installed on the underside or side of an elevated bridge or bridge, it does not require a large space, and can be installed without interfering with the movement of trains or other vehicles on the tracks above the bridge.

FIG. 1 is a perspective view showing an example of an elevated bridge structure. FIG. 2 is a plan view of a corner bending prevention device as an example of an embodiment of the present invention, in which (a) is for a fixed support, and (b) is for a movable support. 1A and 1B are side views of a corner bending prevention device as a different example of an embodiment of the present invention, in which FIG. FIG. 3 is a perspective view showing an installation example of the corner bending prevention device shown in FIG. 2; 3 is a perspective view showing a different installation example of the corner bending prevention device shown in FIG. 2. FIG. 3 is a perspective view showing yet another example of installation of the corner bending prevention device shown in FIG. 2; 4A and 4B are perspective views showing examples of installation of the corner bending prevention device shown in FIG. 3, in which FIG. 4A shows an example of installation on a rigid frame abutment, and FIG. 4B shows an example of installation on a wall-type pier. FIG. 1 is a diagram showing an example of analytical modeling of a viaduct structure. 5A and 5B are graphs modeling the behavior of a corner bending prevention device, where (a) is for a corner bending prevention device for a fixed support, and (b) is for a corner bending prevention device for a movable support. 13 is a graph showing a simulation result showing the relationship between rotational strength and corner bending. It is a graph of simulation results showing the relationship between the tensile strength of the corner folding prevention device and the corner folding occurrence ratio.

The following describes an embodiment of the present invention with reference to the drawings. In this specification and the drawings, elements having substantially the same functional configuration are designated by the same reference numerals to avoid redundant description.

The corner bending prevention device 2 according to an embodiment of the present invention can be installed from outside the track of a viaduct or bridge, which addresses the problems of the above-mentioned conventional technology, which was installed on the top surface of a cantilever slab. Figure 2(a) shows a corner bending prevention device 2 as an example of an embodiment of the present invention. The corner bending prevention device 2 is installed, for example, across the bridge girder 11 on the road and the adjustment girder 13 in the viaduct structure 1 shown in Figure 1, and is used to prevent corner bending 10. In the following description, the rigid frame viaduct 12, adjustment girder 13, rigid frame abutment 14, etc. are collectively referred to as the structure 9.

The corner bending prevention device 2 has two flat base plates 21, 21, a connecting member 22 that connects the base plates 21, 21 together, and an anchor bolt 23 for fixing the base plates 21, 21 to the structure 9. The base plate 21 has a bolt hole 31 for inserting the anchor bolt 23. The anchor bolt 23 can be any of a variety of general post-installed anchors, but considering the effects of vibration, etc., an adhesive anchor is preferable. The connecting member 22 is made of a material having a predetermined cross-sectional performance, which will be described later, such as an H-shaped steel, and is fixed to the base plates 21, 21 by, for example, welding, etc.

The corner bending prevention device 2 shown in Figure 2(a) is an example of a case where it is used on the fixed support side. When it is used on the movable support side, as shown in Figure 2(b), a device that provides clearance (gap) so that the distance between the base plates 21, 21 can be changed when the distance between adjacent structures 9 changes is used. That is, in the example of Figure 2(b), the bolt hole 31 in one of the base plates 21 is a long hole that is long in the bridge axis direction, and can respond to cases where the adjacent structures 9 are horizontally displaced and the distance changes. This is effective in not restricting the expansion and contraction of structural members due to temperature changes, etc. in the movable support.

FIG. 3 shows a different embodiment of the corner bending prevention device 2, in which two flat base plates 21, 21 and a connecting member 22 are connected via brackets 24, respectively. The bracket 24 has surfaces that contact the base plate 21 and the flange 32 of the connecting member 22, respectively, and the bracket 24 and the connecting member 22 are connected with bolts 25. Alternatively, the base plate 21 and the bracket 24 may be integrally molded. FIG. 3(a) is an example of a case where it is used on a fixed bearing side, and when the horizontal distance is variable such as with a movable bearing, as shown in FIG. 3(b), the connecting member 22 and the bracket 24 are used. By connecting them with bolts 6 with a gap provided in the bridge axis direction between them, there is a clearance that can cope with changes in the spacing between the structures 9 due to changes in temperature or the like.

4 to 7 show examples of installation of the corner fold prevention device 2 shown in FIG. 2 or 3. As mentioned above, the corner bending prevention device 2 according to the embodiment of the present invention is characterized in that it can be installed from outside the track of a viaduct or bridge.

Figure 4 shows an example of the installation of the corner bending prevention device 2 in Figure 2. The corner bending prevention device 2 is installed across the tips of adjacent cantilever slabs 41, and the base plate 21 is abutted against the underside of the cantilever slab 41 of the viaduct or bridge structure 9. In this example, first, holes for anchor bolts 23 are formed in the position on the underside of the cantilever slab 41 where the base plate 21 is to be attached, in line with the bolt holes 31 of the base plate 21. Then, by abutting the base plate 21 at a predetermined position and driving in the anchor bolts 23, the two base plates 21, 21 are fixed to the undersides of the adjacent cantilever slabs 41, respectively, and the corner bending prevention device 2 and the structure 9 are integrated. This suppresses the phase difference between the adjacent structures 9 and prevents corner bending. For example, in the case of a girder with a small number of main girders, the overhang length of the cantilever slab 41 is relatively large, so in many cases it is possible to secure space to connect the undersides of the cantilever slabs 41 of adjacent girders, and the construction method shown in Figure 4 is useful. Thus, according to this embodiment, by attaching the corner bending prevention device 2 to the underside of the viaduct structure, construction can be carried out during the day without affecting the viaduct track.

Figure 5 shows a different installation example of the corner bending prevention device 2 of Figure 2, where the corner bending prevention device 2 is installed across the main beams 42 of adjacent cantilever slabs 41. In the example of Figure 5, holes for anchor bolts 23 are formed in alignment with the bolt holes 31 of the base plate 21 at the position where the base plate 21 is attached on the side of the main beam 42 of the structure 9. Then, by abutting the base plate 21 at a predetermined position and driving in the anchor bolt 23, the two base plates 21, 21 are fixed to the side of the main beam 42, respectively, and the corner bending prevention device 2 and the structure 9 are integrated.

FIG. 6 shows a further different installation example of the corner fold prevention device 2 shown in FIG. 1, in which the corner fold prevention device 2 is installed across the ground coverings 43 of adjacent cantilever slabs 41. In the example of FIG. 6, holes for anchor bolts 23 are formed on the outer surface of the ground cover 43 at positions where the base plate 21 is attached, in alignment with the bolt holes 13 of the base plate 21. Then, by abutting the base plate 21 at a predetermined position and driving the anchor bolt 23, the two base plates 21, 21 are respectively fixed to the outer surface of the ground covering 43, and the corner bending prevention device 2 and the structure 9 are integrated. be converted into In many elevated structures, the ground covering 43 is continuous at the tip of the cantilever slab 41, so it is possible to construct the ground covering 43 in this way.

Figure 7 shows an example of installation where the base plates 21, 21 are attached to different structural members. Figure 7(a) shows a case where one is attached to the underside of the main beam 42 and the other to the side of the girder 44 of the rigid frame abutment 14, and Figure 7(b) shows a case where one is attached to the underside of the cantilever slab 41 and the other to the body of the wall-type pier 15. In the case of the rigid frame abutment 14 and the body of the wall-type pier 15, the installation location is considered to have a relatively large degree of freedom, so the installation position in the paired superstructure is assumed to be the cantilever slab 41 or the main beam 42. In this case, since the installation directions of the two base plates 21, 21 are different, the base plate 21 and the connecting member 22 are connected via a bracket 24 of a shape corresponding to the installation directions. In the case of Figure 7, it is also possible to perform the installation without affecting the viaduct track.

In the embodiment shown in Figures 4 to 7, the corner bending prevention device 2 can be applied whether or not there is clearance.

As described above, according to the present invention, the corner bending prevention device 2 for railway viaducts and bridges can be installed without construction on the track. In each of the above embodiments, it is preferable to provide a means, such as a net or chain, to prevent the corner bending prevention device 2 from falling downward when it is damaged during an earthquake or the like.

Next, we will explain the specifications required to apply the corner bending prevention device 2 of the present invention to railway rigid frame abutments and railway piers.

As shown in Figure 1, a numerical analysis was performed using a model of a typical group of structures of an overhead bridge consisting of a rigid-frame railway viaduct 12, PC girder (bridge girder 11), rigid-frame abutment 14, and adjustment girder 13, and the analysis results quantitatively clarified the specifications of the corner bending prevention device 2 and its corner bending suppression effect. This allowed us to determine the optimal specifications of the corner bending prevention device 2 that can be applied to structures such as viaducts and bridges that include rigid-frame abutments 14.

FIG. 8 shows an example of modeling of the viaduct structure 1. A rigid-frame abutment RA is installed at a position spanning the central road, and a rigid-frame viaduct R is installed before and behind it in the bridge axis direction. F in FIG. 8 represents a fixed bearing, and M represents a movable bearing. This model is a typical pattern for elevated structures.

The behavior of the corner bending prevention device 2 was modeled as shown in Figure 9, which shows the relationship between horizontal displacement δ and horizontal force P. Figure 9(a) shows the behavior model for the corner bending prevention device without a clearance, while Figure 9(b) shows the behavior model for the case with a clearance.

The effectiveness of the corner-break prevention device 2 varies depending on the installation position perpendicular to the bridge axis from the center of the structure 9, but it has been found that if the corner-break prevention device 2 has a certain degree of rotational rigidity, its effectiveness can be grasped by the rotational strength (yield moment) My of the corner-break prevention device 2.
My = 2Py × L ... (1')
Py: Yield strength in the tensile direction of the connecting member of the corner bending prevention device L: Distance from the center of the structure to the corner bending prevention device

Figure 10 shows the results of a simulation in which an anti-corner bending device 2 that exhibits the behavior shown in Figure 9 is used in the viaduct structure shown in Figure 8, and a seismic wave is applied to perform a response analysis. From Figure 10, it can be seen that the decrease in the amount of corner bending reaches a plateau when the rotational strength My is about 4000 kN·m, and even if the rotational strength My is further increased, the corner bending prevention effect hardly increases. In other words, the corner bending prevention device 2 according to the embodiment of the present invention only needs to have a predetermined rotational strength calculated from the yield strength Py of the connecting member 22 and the distance L from the center of the structure to the corner bending prevention device 2, and assuming that the device exhibits behavior like the model in Figure 9, the effect of the corner bending prevention device 2 can be efficiently demonstrated with a rotational strength My of, for example, about 4000 kN·m. This makes it possible to easily change the design using formula (1') when the construction position of the corner bending prevention device 2 is changed for some reason or when it is diverted to a structure with approximately the same structure.

A specific example of the specifications of the corner bending prevention device 2 will be explained. For example, if the distance L from the center of the structure to the corner bending prevention device 2 is 4.5 m when constructed in the position shown in FIG. The proof strength (load) Py is
Py=My/2L...(1)
My: Rotational strength required to suppress corner bending of the structure L: Obtained from the distance from the center of the structure to the corner bending prevention device. In addition, FIG. 11 shows the results obtained by simulation of the corner fold ratio in the case of no reinforcement and in the case of reinforcement with the corner fold prevention device 2 having rotational strength. From FIG. 11, it can be seen that when the tensile yield strength (load) Py of the connecting member 22 of the corner fold prevention device 2 is around 400 kN, the corner fold occurrence rate decreases significantly, and even if the yield strength Py exceeds 400 kN, the corner fold prevention effect does not change. It turns out that there isn't. In other words, when the yield strength Py is 400 kN, the effect of the corner bending prevention device can be efficiently exhibited. As an example of the connecting member 22 whose yield strength (load) Py corresponds to about 400 kN, H-beam steel of H-100×100 (SS400) can be used. In addition to steel, the material of the connecting member 22 may be CFT, for example, as long as it has the required strength.

Additionally, if a member other than the connecting member 22 yields when a large horizontal force such as an earthquake is applied, it is assumed that the load-displacement relationship will become complicated, and if the slab of the viaduct or bridge structure is destroyed, it will be difficult to repair. Therefore, it is preferable that the corner bending prevention device 2 is designed so that the base plate 21 and the anchor bolt 23 do not yield before the connecting member 22.

That is, the cross-sectional area and number of the anchor bolts 23 are designed so that the total shear strength of the anchor bolts 23 is greater than the tensile strength of the connecting member 22. The tensile strength of the anchor bolts 23 only needs to be sufficient to support the weight of the corner bending prevention device 2. When the connecting member 22 and the bracket 24 are connected by the bolts 25, the cross-sectional area and number of the bolts 25 are designed so that the tensile strength of the bolts 25 is not less than the tensile strength of the connecting member 22. The plate thickness of the base plate 21 and the bracket 24 may be determined based on the strength design of a normal steel structure. In the present invention, the base plate 21, the bracket 24, the bolts 25, etc. are preferably made of steel, but this does not exclude other materials having the same characteristics and strength as the steel.

As described above, the corner bending prevention device according to the embodiment of the present invention can prevent structurally different structures such as railway viaducts and bridges from vibrating at different natural periods during an earthquake, and can physically suppress the relative displacement between adjacent structures, thereby preventing corner bending between adjacent structures and improving the running performance of trains, etc.

Moreover, it can also be applied to overhead bridges where corner bending is prominent, and can be attached to the underside or side of a structure, allowing for a great deal of freedom in installation location. This means that construction work can be carried out during the day without affecting the viaduct tracks or interfering with train and other traffic.

In addition, by clarifying the strength and corner-break prevention effect required for the components of the corner-break prevention device 2, reinforcement measures for viaducts and bridges will be promoted.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to such examples. It is clear that those skilled in the art can come up with various changes or modifications within the scope of the technical idea described in the claims, and these naturally fall within the technical scope of the present invention. It is understood that it belongs to

INDUSTRIAL APPLICABILITY The present invention is useful as a corner bending prevention device for structures adjacent in the axial direction of a bridge, such as viaducts and bridges, where the types of structures are different.

Reference Signs List 1 Viaduct structure 2 Corner bending prevention device 9 Structure 10 Corner bending 11 Bridge girder 12 Rigid frame viaduct 13 Adjustment girder 14 Rigid frame abutment 15 Wall-type bridge pier 21 Base plate 22 Connecting member 23 Anchor bolt 24 Bracket 25 Bolt 31 Bolt hole 32 Flange 41 Cantilever slab 42 Main beam 43 Ground cover 44 Girder

Claims (10)

An angle bending prevention device that is installed across structures that are adjacent to each other in the bridge axis direction on a viaduct or bridge,
Two base plates are disposed at the ends of the adjacent structures facing each other;
A connecting member that connects the base plates to each other;
and an anchor bolt for fixing the base plate to the structure.
The base plate is disposed directly on the end of the structure without a support member;
A corner bending prevention device for a viaduct or bridge, characterized in that two adjacent structures and the corner bending prevention device are arranged in series in the bridge axis direction. The corner bending prevention device for a viaduct or bridge according to claim 1, further comprising a bracket that connects the two base plates and the connecting member. The corner bending prevention device for a viaduct or bridge according to claim 1 or 2, characterized in that a clearance is provided that can accommodate displacement of the structure in the bridge axis direction. The corner bending prevention device for viaducts or bridges described in claim 3, characterized in that the clearance is provided by making the bolt hole for the anchor bolt formed in one of the base plates a long hole in the bridge axis direction. The corner bending prevention device for viaducts or bridges described in claim 3, characterized in that the connection portion between the connecting member and one of the base plates is connected with a gap in the bridge axis direction, thereby providing the clearance. The yield strength Py of the connecting member in the tensile direction satisfies formula (1),
The rotational resistance My is obtained by a simulation in which the structure is modeled, and is the rotational resistance when the amount of bending of the structure becomes equal to or less than a certain value. The corner bending prevention device for a viaduct or bridge according to any one of claims 1 to 5.
Py=My/2L (1)
My: Rotational strength required to prevent the structure from bending. L: Distance from the center of the structure to the bending prevention device. The corner bending prevention device for a viaduct or bridge according to claim 6, wherein the rotational strength My is 4000 kN·m or more. Any one of claims 1 to 7, wherein when installed at a position 4.5 m from the center of a structure having an overpass, the connecting member has a horizontal proof stress of 400 kN or more in the axial direction of the bridge. The corner bending prevention device for viaducts or bridges according to item 1. The corner bending prevention device for viaducts or bridges described in any one of claims 1 to 8, characterized in that the total shear strength of the anchor bolts is greater than the horizontal strength of the connecting member. A method for preventing corner bending of a viaduct or bridge, comprising installing the corner bending prevention device according to any one of claims 1 to 9 on the outside of a track of the viaduct or bridge structure.

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