JP3676112B2 - Viaduct substructure and design method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a viaduct substructure mainly used for roads, railways, and the like, and a design method thereof.
[0002]
[Prior art]
Bridges such as roads and railroads include so-called viaducts that are continuously built in urban areas, in addition to narrowly-defined bridges that cross rivers and straits. Such viaducts are constructed continuously in space on roads, railroads or rivers from the viewpoint of efficient land use, and when roads and roads or roads and railroads intersect on a plane, By making either of these viaducts, it is possible to eliminate traffic congestion.
[0003]
Here, when a viaduct is constructed on a road or railway in service, the following problems arise.
[0004]
That is, the foundation beam 1 is indispensable as shown in FIG. 9 in order to ensure the horizontal rigidity in the direction orthogonal to the bridge axis in the substructure of the viaduct of roads and railways. Therefore, as shown in FIG. 10 (a), for example, when the track 2 is in service as a business route, in order to construct a viaduct on the track site and move the business route to the elevated, first, FIG. 10 (b) As shown in Fig. 2, the track 2 is temporarily moved as a temporary track 3 to the side of the viaduct construction planned space, and then the viaduct 3 is used as a business route during the construction period, and the viaduct substructure having the foundation beam 1 is used. Build 4. After the viaduct substructure 4 is completed, the temporary track 3 is generally removed and the track 6 newly laid on the viaduct superstructure 5 is used as a business route. .
[0005]
[Problems to be solved by the invention]
However, in such a procedure, a land for laying the temporary track 3 must be secured on the side of the viaduct during the construction period, and the private house is approaching, not only the problem of land acquisition cost In such a densely populated area, it has become a problem that it is extremely difficult to make railroads and roads elevated.
[0006]
In addition, when designing and constructing the substructure of a railway viaduct, the safety of the vehicle as well as the soundness of the viaduct itself at the time of an earthquake must be fully considered. When encountering a huge earthquake, there was some concern with the conventional viaduct whether or not the safety of the traveling vehicle could be ensured.
[0007]
The present invention has been made in consideration of the above-described circumstances, and is a viaduct that can be used to move an existing road or railroad to an elevated without using an extra land acquisition while still being used as it is. It aims at providing the substructure of.
[0008]
Another object of the present invention is to provide a substructure for a railway viaduct and a method for designing the same, which can ensure the safety of a vehicle traveling on the viaduct even when a major earthquake is encountered. To do.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the viaduct substructure according to the present invention is spanned between a pair of columnar piers erected at opposite positions and the top of the columnar piers as described in claim 1. A brace material having an inverted V shape is disposed in an in-plane space including the pair of columnar piers and the beam, and the vicinity of the top of the brace material is joined to the vicinity of the center of the beam. By joining both ends in the vicinity of the intermediate height position of the pair of columnar piers, the deformation of the ramen structure when a horizontal force is applied is orthogonal to the bridge axis of the brace material without installing a foundation beam. It is configured so that it can be suppressed by the rigidity in the horizontal direction.
[0010]
In addition, the underpass structure of the viaduct according to the present invention forms a ramen structure from a columnar pier erected in parallel with the bridge axis and a beam spanned on the top of the columnar pier and is adjacent to the columnar pier. By placing a pair of matching columnar piers and a brace material having an inverted V shape in the in-plane space including the beam, the foundation beam can be installed to deform the ramen structure when a horizontal force acts in the direction of the bridge axis. At least, the brace material can be restrained by the rigidity in the bridge axis direction.
[0011]
In the viaduct substructure according to the present invention, a predetermined energy absorbing damper is interposed between the vicinity of the top of the brace material and the beam.
[0012]
In addition, the substructure of the railway viaduct according to the present invention includes a pair of columnar piers erected at positions facing each other and a beam spanned on the top of the columnar pier as described in claim 4. A brace material having an inverted V shape is disposed in an in-plane space including the pair of columnar piers and the beam, and the vicinity of the top portion of the brace material is interposed through a predetermined energy absorbing damper. It is a substructure of a railway viaduct that is joined in the vicinity of the center and both ends are joined in the vicinity of the intermediate height position of the pair of columnar piers, and the natural frequency of the railway viaduct in the direction perpendicular to the bridge axis is 2 Hz. It is comprised so that it may become the above.
[0013]
In addition, the substructure of the railway viaduct according to the present invention includes a pair of columnar piers erected at positions facing each other and a beam spanned on the top of the columnar pier as described in claim 5. A brace material having an inverted V shape is disposed in an in-plane space including the pair of columnar piers and the beam, and the vicinity of the top portion of the brace material is interposed through a predetermined energy absorbing damper. It is a substructure of a railway viaduct that is joined in the vicinity of the center and both ends are joined in the vicinity of the middle height position of the pair of columnar piers, and the excitation frequency at the track laying position of the railway viaduct and the vibration frequency Create a graph by superimposing a driving safety limit curve that divides a safety region and a derailment region related to driving safety on a group of curves obtained for each excitation acceleration and the relationship with the lateral displacement amplitude of the track. design The vibration frequency of the travel safety limit curve corresponding to the vibration acceleration is determined, and the natural frequency in the direction perpendicular to the bridge axis of the railway viaduct is designed to be equal to or higher than the vibration frequency. .
In addition, the design method of the substructure of the railway viaduct according to the present invention is spanned between a pair of columnar piers erected at positions facing each other and the top of the columnar piers as described in claim 6. A brace material having an inverted V shape is disposed in an in-plane space including the pair of columnar piers and the beam, and the vicinity of the top of the brace material is interposed via a predetermined energy absorbing damper. A method for designing a substructure of a railway viaduct that is joined to the vicinity of the center of the beam and has both ends joined to the vicinity of an intermediate height position of the pair of columnar piers, at a track laying position of the viaduct for the railway A graph was created by superimposing a driving safety limit curve that divides a safety area and a derailment area related to driving safety on a group of curves obtained by determining the relationship between the excitation frequency and the lateral displacement amplitude of the track for each excitation acceleration. , Using the graph, the vibration frequency of the travel safety limit curve corresponding to the design vibration acceleration is obtained, and the natural frequency in the direction perpendicular to the bridge axis of the railway viaduct is equal to or higher than the vibration frequency. It is something to design.
[0014]
In the viaduct substructure of the present invention according to claim 1, a brace material having an inverted V shape is disposed in an in-plane space including a pair of columnar piers and beams, and the brace material is orthogonal to the bridge axis. Since the rigidity in the horizontal direction is ensured, the deformation of the ramen structure when a horizontal force acts in the direction is sufficiently suppressed without installing a foundation beam. Also, since the vicinity of the top of the brace material is joined to the vicinity of the center of the beam, and both ends are joined to each other near the middle height position of the pair of columnar piers, a large space is created below the brace material, as a road or railway It can be used effectively.
[0015]
Further, in the substructure of the viaduct according to claim 2, since the rigidity in the bridge axis direction is ensured by the brace material, the deformation of the ramen structure when a horizontal force is applied in the direction does not install the foundation beam. Both are sufficiently suppressed.
[0016]
The viaduct referred to in the present invention is a concept including a viaduct for railways, a viaduct for roads, etc., and its use is arbitrary.
[0017]
Here, the vicinity of the top of the brace material having an inverted V shape may be directly joined to the vicinity of the center of the beam, but if a predetermined energy absorbing damper is interposed between them, the vibration energy at the time of the earthquake is reduced. It can be absorbed by the energy absorbing damper and the shaking of the viaduct can be quickly converged.
[0018]
In addition, as a structural form which comprises a ramen structure, not only reinforced concrete structure but steel structure, steel frame reinforced concrete structure, etc. are included. Further, the structure, material type, or arrangement method of the brace material is arbitrary, and may resist both directions of compression and tension, or may resist only in the tension direction. Moreover, as the material, steel frame material, PC steel wire or the like can be used.
[0019]
In the substructure of the railway viaduct of the present invention according to claim 4, the energy absorption damper interposed between the ramen structure and the brace material against the vibration of the earthquake motion along the direction orthogonal to the bridge axis has its vibration energy. Absorbs and quickly converges the shaking of the railway viaduct. In particular, since the natural frequency of the railway viaduct in the direction perpendicular to the bridge axis is 2 Hz or more, the rolling of the railway viaduct is effectively suppressed, and the running safety of the vehicle traveling on the viaduct is suppressed. Is greatly improved. In addition, what is necessary is just to determine the magnitude | size about the cross section of the ramen structure which comprises a lower structure, a brace material, etc. by vibration analysis or a vibration experiment using a vibrator.
[0020]
On the other hand, the energy of the input earthquake motion is consumed in the form of hysteresis damping, viscous damping, etc. of the energy absorption damper, and the ramen structure and brace material, which are the main structures of the underpass of the railway viaduct, are hardly damaged and are healthy. Maintain sex. Therefore, after the earthquake, the use of the railway viaduct can be continued as before by replacing the energy absorbing damper with a new one.
[0021]
The substructure of the railway viaduct according to claims 5 and 6 and the design method thereof include a pair of columnar piers erected at positions facing each other and a beam bridged on the top of the columnar pier. A brace material having an inverted V shape is disposed in an in-plane space including the pair of columnar piers and the beam, and the vicinity of the top portion of the brace material is interposed through a predetermined energy absorbing damper. It is a substructure of a railway viaduct that is joined in the vicinity of the center and both ends are joined in the vicinity of the intermediate height position of the pair of columnar piers. The substructure is designed according to the following procedure.
[0022]
That is, first, the safety area and the derailment area related to driving safety are divided into a group of curves obtained by determining the relationship between the excitation frequency at the track laying position of the railway viaduct and the lateral displacement amplitude of the track for each excitation acceleration. Create a graph that overlays the driving safety limit curves.
[0023]
Next, the vibration frequency of the traveling safety limit curve corresponding to the designed vibration acceleration is obtained using such a graph.
[0024]
Next, the lower structure is determined so that the natural frequency in the direction perpendicular to the bridge axis of the railway viaduct is equal to or higher than the excitation frequency.
[0025]
If it does in this way, within the range of the design excitation acceleration, the running safety of vehicles which run on a viaduct for railways is certainly guaranteed.
[0026]
In order to design the substructure so that the natural frequency in the direction perpendicular to the bridge axis of the railway viaduct is equal to or higher than the vibration frequency obtained from the above graph, the ramen structure, A method of determining the cross-section of the brace material or the like by vibration analysis or a vibration experiment using a vibrator is considered.
[0027]
In addition, in the substructure of the railway viaduct according to claims 4 and 5, how to construct the energy absorbing damper is arbitrary, but for example, a hysteresis damping type composed of ultra mild steel or slit steel sheet It can be a member. The material of which the ramen structure and brace material are composed is arbitrary, and the brace material can be composed of, for example, PC steel wire, but the ramen structure is generally composed of reinforced concrete and the brace material is composed of steel frame. It is a form.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a viaduct substructure and a design method thereof according to the present invention will be described below with reference to the accompanying drawings. Note that components that are substantially the same as those of the prior art are assigned the same reference numerals, and descriptions thereof are omitted.
[0029]
(First embodiment)
[0030]
FIG. 1 is a front view of the viaduct substructure according to the present embodiment as viewed from the bridge axis direction. As can be seen in the figure, the viaduct substructure 10 according to the present embodiment includes a pair of columnar piers 11 and 11 erected at positions facing each other, and a beam 12 spanning the top of the columnar pier. A brace material 14 having an inverted V shape is disposed in an in-plane space including a pair of columnar piers 11, 11 and a beam 12. Here, the columnar pier 11 is erected on a footing 17 provided on the pile 16 after driving the pile 16.
[0031]
The ramen structure 13 including the pair of columnar piers 11 and 11 and the beam 12 bridged over the top of the columnar pier may be, for example, a reinforced concrete structure, and the brace member 14 may be, for example, a steel frame structure.
[0032]
The brace material 14 is joined to the vicinity of the center of the beam 12 in the vicinity of the top portion thereof, and both ends thereof are joined to the vicinity of the intermediate height position of the pair of columnar piers 11 and 11, respectively. In the vicinity of the top, it is joined to the beam 12 via an energy absorbing damper 15.
[0033]
The energy absorption damper 15 can be configured by inserting a large number of slits in a normal thin steel plate, or can be configured by using an extremely mild steel. The energy absorbing damper 15 is preferably detachably attached between the brace material 14 and the beam 12 so that it can be replaced during maintenance.
[0034]
In order to construct the viaduct substructure 10 according to this embodiment, first, columnar piers 11 and 11 are erected on both sides of the track 2 in service as a business route, and a beam 12 is bridged near the top. A ramen structure 13 is constructed. Next, the brace member 14 and the energy absorbing damper 15 are attached to the ramen structure 13 to complete the viaduct substructure 10.
[0035]
Here, since it is not necessary to construct a foundation beam for connecting the leg portions of the columnar piers 11, it is not necessary to replace the track 2 during the construction period.
[0036]
If the viaduct lower structure 10 is constructed, the upper structure 5 composed of a bridge girder, floor slab, etc. is bridged in the bridge axis direction, and then the track 6 is laid on the upper structure. Then, the track 2 is removed and the business route is moved to the track 6. About the site | part after removing the track | orbit 2, it can be diverted, for example to a parking lot.
[0037]
In the viaduct substructure 10 according to the present embodiment, a brace material 14 is disposed in an in-plane space including a pair of columnar piers 11 and 11 and a beam 12, and the brace material is used in a horizontal direction perpendicular to the bridge axis. Since rigidity is ensured, deformation of the ramen structure 13 when a horizontal force acts in this direction is sufficiently suppressed without installing a foundation beam.
[0038]
As described above, according to the viaduct substructure 10 according to the present embodiment, the brace material 14 can sufficiently ensure the rigidity in the horizontal direction perpendicular to the bridge axis, which is indispensable in the conventional viaduct. It is possible to omit the foundation beam.
[0039]
Therefore, conventionally, in order to construct the foundation beam, it is necessary to secure the site on the side of the viaduct substructure 4 and lay the track 3 on the site to change the track. In addition to this problem, viaduct construction was extremely difficult in densely populated areas where private houses are approaching, but according to this embodiment, the foundation beam can be omitted, so the construction of the viaduct is to be performed. Therefore, it is not necessary to change the track, and land acquisition on the side of the viaduct will be unnecessary. Therefore, it is possible to construct the viaduct substructure at a much shorter construction period and at a lower cost than before, and it is also possible to construct a viaduct even in a densely populated area where private houses are approaching the viaduct side. .
[0040]
In addition, since the horizontal rigidity of the entire lower structure 10 can be adjusted by changing the thickness, width, or material of the brace material 14, the viaduct substructure is excellent in earthquake resistance considering the frequency characteristics of seismic waves. 10 can be constructed.
[0041]
Further, according to the present embodiment, the vicinity of the top of the brace material 14 having an inverted V shape is joined to the vicinity of the center of the beam 12, and both ends are joined to the vicinity of the intermediate height position between the pair of columnar piers 11 and 11, respectively. Therefore, a large space can be secured below the brace material 14.
[0042]
Accordingly, in this embodiment, the track 2 is removed. However, if there is no problem with traffic crossing the plane, the track 2 can be used as a business route without being removed, or the track 2 can be removed. After that, it can be used as a road.
[0043]
In addition, according to the present embodiment, the vicinity of the top of the brace material 14 having an inverted V shape is joined to the beam 12 via the energy absorption damper 15, so that the vibration energy at the time of the earthquake is absorbed by the energy absorption damper 15, It becomes possible to quickly converge the shaking of the viaduct in the direction perpendicular to the bridge axis.
[0044]
In the present embodiment, the superstructure 5 of the viaduct has not been described in detail, but the structure type is arbitrary, and not only a conventional (ramen type) superstructure using a heavy concrete slab, but also a hollow bridge girder. , Using light weight material for the handrail, supporting the track with a predetermined elastic support without using heavy ballast, double line, double line, etc. that only support the single line of the railway As a matter of course, the desired number of bridges (for example, the superstructure described in the specification of Japanese Patent Application No. 9-312039) is also an object.
[0045]
Further, in this embodiment, the hysteresis damping type is used as the energy absorption damper, but the present invention is not limited to this type, and it is also possible to use a viscous damping type or friction damping type.
[0046]
(Second Embodiment)
[0047]
Next, a second embodiment will be described. Note that components that are substantially the same as those of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0048]
FIG. 2 is a side view of the viaduct substructure according to the second embodiment viewed from a direction perpendicular to the bridge axis. As can be seen in the figure, the viaduct substructure 21 according to the present embodiment is bridged over a number of columnar piers 22 standing at predetermined intervals so as to be parallel to the bridge axis and the top of the columnar piers. A braided material 24 having an inverted V shape is disposed in an in-plane space including a pair of adjacent columnar piers 22 and 22 and the beam 23 among the columnar piers 22. Here, the columnar pier 22 is erected on the footing 17 provided on the pile 16 after driving the pile 16.
[0049]
The ramen structure including the columnar pier 22 and the beam 23 bridged over the top of the columnar pier may be a reinforced concrete structure, and the brace member 24 may be a steel structure, for example.
[0050]
A brace material 24 having an inverted V shape is joined to the vicinity of the center of the beam 23 via an energy absorbing damper 25 and both lower ends thereof are joined to the vicinity of the lower end of the columnar pier 22. Since the energy absorption damper 25 has the same configuration as the energy absorption damper 15, the description thereof is omitted here.
[0051]
In the viaduct substructure 21 according to the present embodiment, the brace material 24 is disposed in the in-plane space including the adjacent columnar piers 22 and 22 and the beam 23, and the brace material ensures rigidity in the bridge axis direction. Therefore, the deformation of the ramen structure when a horizontal force is applied in the direction is sufficiently suppressed without installing a foundation beam.
[0052]
As described above, according to the viaduct substructure 21 according to the present embodiment, it is possible to sufficiently ensure the rigidity in the bridge axis direction by the brace material 24. Omitting it enables rapid construction and cost reduction. In addition, since the horizontal rigidity of the entire lower structure 21 can be adjusted by changing the thickness, width, or material of the brace material 24, the viaduct substructure having excellent earthquake resistance in consideration of the frequency characteristics of seismic waves and the like. 21 can be constructed.
[0053]
In addition, according to the present embodiment, the vicinity of the top of the brace material 24 having an inverted V shape is joined to the beam 23 via the energy absorbing damper 25, so that the vibration energy at the time of the earthquake is absorbed by the energy absorbing damper 25, It is possible to quickly converge the shaking of the viaduct in the bridge axis direction.
[0054]
(Third embodiment)
[0055]
Next, the substructure of the railway viaduct according to the third embodiment will be described. Note that components that are substantially the same as those of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0056]
FIG. 3 is a front view of the lower structure 30 of the railway viaduct according to the present embodiment as viewed from the bridge axis direction. As can be seen in the figure, the railroad viaduct substructure 30 according to this embodiment is also a pair of columnar piers 31 erected at positions facing each other, like the viaduct substructure 10 according to the first embodiment. , 31 and a beam 32 bridged over the top of the columnar pier, a ramen structure 33 is formed, and a brace member 34 having an inverted V shape is formed in an in-plane space including the pair of columnar piers 31, 31 and the beam 32. It is arranged.
[0057]
The ramen structure 33 including the pair of columnar piers 31 and 31 and the beam 32 bridged over the top of the columnar pier can be a reinforced concrete structure, for example, and the brace member 34 can be a steel frame structure, for example.
[0058]
The brace member 34 is joined to the vicinity of the center of the beam 32 via the energy absorbing damper 35 in the vicinity of the top portion thereof, and both ends thereof are joined to the vicinity of the intermediate height position between the pair of columnar piers 31 and 31. is there.
[0059]
The energy absorbing damper 35 can be configured by inserting a large number of slits in a normal thin steel plate, or can be configured by using an extremely mild steel. The energy absorbing damper 35 is preferably detachably attached between the brace member 34 and the beam 32 so that it can be replaced during maintenance.
[0060]
Here, the lower structure 30 of the railway viaduct 37 according to the present embodiment has a ramen structure so that the natural frequency in the direction perpendicular to the bridge axis of the railway viaduct 37 including the lower structure and the upper structure 5 is 2 Hz or more. 33, the cross-section and material of the brace material 34 and the energy absorbing damper 35 are determined. In determining these cross-sections, etc., it may be determined by analysis, for example, or a vibration test is performed by installing a vibrator on the railway viaduct 37 or its experimental model, and the viaduct or its experimental model is actually Alternatively, the cross-section of each member described above may be determined so as to resonate at 2 Hz or higher.
[0061]
Here, in determining the cross sections and materials of the ramen structure 33, the brace material 34, and the energy absorbing damper 35, as shown in the restoring force characteristics of FIG. ₁ ) The energy absorption damper 35 yields (after point A in the figure) when it encounters a massive earthquake that is deformed within the range of In order to efficiently absorb the seismic energy, the maximum value of each member is θ in FIG. ₁ And θ ₂ It is better to assume that it falls between.
[0062]
That is, on the assumption that the lower structure 30 vibrates in a state where the rigidity is lower than the initial rigidity, each of the lower structures constituting the lower structure so that the natural frequency in the direction perpendicular to the bridge axis of the railway viaduct 37 is 2 Hz or more. It is preferable to determine the cross section of the member. If the cross section is set in this way, the initial rigidity (O to θ in FIG. ₁ ) Greater than 2 Hz is maintained for earthquakes that are deformed within the range of
[0063]
The overall restoring force characteristic of the lower structure 30 is a curve that continues from the origin O to B, C, and D, as can be seen in FIG. 4, but in terms of design, the restoring force that continues from the origin O to C and D. It may be regarded as a characteristic. In this case, the rigidity P extending from the origin O to C ₂ / Θ ₂ Can be thought of as equivalent stiffness considering the actual hysteresis behavior when a huge earthquake is assumed.
[0064]
In the lower structure 30 of the railway viaduct 37 according to the present embodiment, the rolling of the viaduct is suppressed by designing the natural frequency in the direction orthogonal to the bridge axis of the railway viaduct 37 to be 2 Hz or more. The traveling safety of the vehicle traveling on the vehicle is greatly improved.
[0065]
5 and 6 are analysis results showing the operational effects of the lower structure 30 of the railway viaduct 37 according to the present embodiment, and the contents thereof will be described below.
[0066]
First, FIG. 5 shows the relationship between the vibration frequency at the track laying position of the railway viaduct 37 and the lateral displacement amplitude of the track for each vibration acceleration to obtain a group of curves 41, while each vibration frequency. Investigate how the driving safety of the vehicle changes depending on the magnitude of the lateral displacement amplitude. Plot ○ if it is safe, x if it is derailed, then ○ is distributed. This is a graph in which a curve is drawn at a boundary portion between a safety region and a derailment region where x is distributed, this is defined as a traveling safety limit curve 42 and superimposed on a curve group 41. In examining the running safety, the running speed was set to 100 km / h.
[0067]
From this graph, it is difficult to ensure traveling safety even with an acceleration of about 500 gal at an excitation frequency of 1 Hz or less, but traveling safety can be ensured at an excitation frequency of 1.5 Hz. It can be seen that the upper limit of acceleration increases to about 900 gal, and the upper limit is further about 1400 gal at the excitation frequency of 2 Hz.
[0068]
Therefore, if a relatively large earthquake with a value on the ground surface of about 300 gal is targeted, the natural frequency of the railway viaduct 37 should be set to about 1.5 Hz even if amplification from the ground surface is taken into account. For example, the safety of the vehicle traveling on the railway viaduct is ensured.
[0069]
In addition, even if the target is a huge earthquake of a direct type with a value on the ground surface exceeding 800 gal, if the natural frequency of the railway viaduct 37 is set to about 2 Hz or more, the vehicle travels. It can be seen that sufficient stability can be secured.
[0070]
Next, FIG. 6 shows the analysis results of examining the relationship between the natural frequency of the viaduct and the derailment coefficient (Q / P) using two actual seismic waves (maximum acceleration: 300 gal) for each of the three types of ground. It is a graph. Here, Q represents the horizontal force applied to the track from the chassis of the traveling vehicle, P represents the dynamic wheel load applied from the chassis to the track, and the greater the Q / P, the lower the traveling stability. The traveling speed was 260 km / h.
[0071]
From this graph, it can be seen that the derailment coefficient is large at around 1 Hz, whereas the derailment coefficient is relatively small at 2 Hz and above, and the driving safety is improved.
[0072]
As described above, according to the lower structure 30 of the railway viaduct 37 according to the present embodiment, the brace material disposed in the ramen structure 33 and its in-plane space and connected to the ramen structure via the energy absorbing damper 35. 34, the energy absorption damper 35 interposed between the ramen structure 33 and the brace material 34 absorbs the vibration energy against the vibration of the earthquake motion along the direction orthogonal to the bridge axis. The shaking of the commercial viaduct 37 is quickly converged.
[0073]
On the other hand, the energy of the input seismic motion is consumed as the hysteresis attenuation of the energy absorbing damper 35, and the ramen structure 33 and the brace material 34, which are the main structures of the lower structure 30 of the railway viaduct 37, are hardly damaged and are sound. To maintain. Therefore, after the earthquake, the use of the railway viaduct 37 can be continued as before by replacing the energy absorbing damper 35 with a new one.
[0074]
Further, according to the lower structure 30 of the railway viaduct 37 according to the present embodiment, it is possible to design a displacement centering on the deformation performance of the energy absorbing damper 35, and a design method that depends on the complex RC deformation performance as in the prior art. A more rational design is possible.
[0075]
Further, according to the lower structure 30 of the railway viaduct 37 according to the present embodiment, the residual deformation due to the earthquake of the ramen structure 33 can be restored by taking the reaction force from the brace material 34, and the damage at the time of the earthquake Control can be easily performed.
[0076]
In addition, according to the lower structure 30 of the railway viaduct 37 according to the present embodiment, since the natural frequency in the direction perpendicular to the bridge axis of the railway viaduct is 2 Hz or more, However, the rolling safety of the railway viaduct 37 can be suppressed and the traveling safety of the vehicle traveling on it can be ensured.
[0077]
In the present embodiment, the lower structure 30 has a single layer structure, but it is needless to say that the lower structure 30 may have a multilayer structure.
[0078]
Further, in this embodiment, the hysteresis damping type is used as the energy absorption damper, but the present invention is not limited to this type, and it is also possible to use a viscous damping type or friction damping type.
[0079]
(Fourth embodiment)
[0080]
Next, a fourth embodiment will be described. Note that components that are substantially the same as those of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0081]
The lower structure of the railway viaduct according to this embodiment is the same as the lower structure 30 of the railway viaduct 37 shown in FIG. 3, but in this embodiment, the lower structure 30 is constructed according to the design flowchart shown in FIG. It is.
[0082]
That is, in designing the substructure 30 of the railway viaduct 37 according to this embodiment, first, the relationship between the vibration frequency at the track laying position of the railway viaduct 37 and the lateral displacement amplitude of the railway is excited. A graph is created as shown in FIG. 5 by superimposing a travel safety limit curve that divides a safety region related to travel safety and a derailment region on a group of curves obtained for each acceleration (step 101). Since the driving safety limit curve is the same as the concept described in the third embodiment, the description thereof is omitted here.
[0083]
Next, the vibration frequency of the traveling safety limit curve corresponding to the designed vibration acceleration is obtained using such a graph (step 102). The graph of FIG. 8 shows a method of reading that the excitation frequency is about 1.6 Hz when the design excitation acceleration is 1000 gal.
[0084]
Next, the substructure 30 is designed so that the natural frequency in the direction orthogonal to the bridge axis of the railway viaduct 37 is the excitation frequency obtained in step 102, or 1.6 Hz or more in the above example (step 103). .
[0085]
The method for determining the cross section of the ramen structure 33, the brace material 34, and the energy absorbing damper 35 when designing the lower structure 30 may be determined, for example, by analysis, or may be an exciter in a railway viaduct 37 or its experimental model The section of each member described above may be determined so that the viaduct or the experimental model actually resonates at 2 Hz or more. The handling of the earthquake scale and restoring force characteristics when performing the cross-sectional design is substantially the same as in the third embodiment, and thus the description thereof is omitted here.
[0086]
In this way, if the lower structure 30 is designed so that the natural frequency in the direction orthogonal to the bridge axis of the railway viaduct 37 is 1.6 Hz or more in the above example, within the range of the design excitation acceleration, In the case of the above example, at 1000 gal, as can be seen in FIG. 8, the excitation acceleration is below the travel safety limit curve, and the travel safety of the vehicle traveling on the railway viaduct 37 is ensured.
[0087]
As described above, according to the lower structure 30 of the railway viaduct 37 according to the present embodiment, the natural frequency of the railway viaduct in the direction orthogonal to the bridge axis is a value corresponding to the design excitation acceleration. Therefore, with respect to an earthquake corresponding to the designed acceleration, it is possible to suppress the rolling of the railway viaduct 37 and ensure the traveling safety of the vehicle traveling on it.
[0088]
In the present embodiment, the case where the excitation acceleration on the raceway surface is 1000 gal was taken as an example. However, when the design acceleration is more severe, for example, 1500 gal, as shown in FIG. The frequency may be set to about 2.2 Hz, and conversely if it is about 900 gal, it may be set to about 1.5 Hz.
[0089]
【The invention's effect】
As described above, according to the viaduct substructure according to the first aspect of the present invention, it is possible to sufficiently ensure the rigidity in the horizontal direction perpendicular to the bridge axis by the brace material. In the conventional viaduct substructure, It becomes possible to omit the foundation beam which was indispensable.
[0090]
Accordingly, it is not necessary to change the track for the construction of the viaduct, and the land acquisition on the side of the viaduct is not necessary. Therefore, it is possible to construct the viaduct substructure at a much shorter construction period and at a lower cost than before, and it is also possible to construct a viaduct even in a densely populated area where private houses are approaching the viaduct side. . In addition, a large space is created below the brace material, which can be effectively used as a road or a railway.
[0091]
In addition, according to the viaduct substructure according to the invention of claim 2, it is possible to sufficiently ensure the rigidity in the bridge axis direction by the brace material, and the foundation beam, which is indispensable in the conventional viaduct, is omitted rapidly. Construction and cost reduction are possible. In addition, since the horizontal rigidity of the entire substructure can be adjusted by changing the thickness, width, or material of the brace material, a highly bridged substructure with excellent earthquake resistance that takes into account the frequency characteristics of seismic waves, etc. It becomes possible to do.
[0092]
Moreover, according to the viaduct substructure according to the invention of claim 3, the vibration energy at the time of earthquake is absorbed by the energy absorption damper, and the vibration of the viaduct in the direction perpendicular to the bridge axis or in the bridge axis direction is quickly converged. There is also an effect that is possible.
[0093]
Further, according to the substructure of the viaduct of the present invention according to claim 4, the energy absorption interposed between the ramen structure and the brace material against the vibration of the earthquake motion along the direction orthogonal to the bridge axis. The member absorbs the vibration energy and quickly converges the vibration of the viaduct, and in particular, the substructure is constructed so that the natural frequency in the direction perpendicular to the bridge axis is 2 Hz or more. It is possible to effectively suppress the shaking and greatly improve the traveling safety of the vehicle traveling on the viaduct.
[0094]
On the other hand, the energy of the input seismic motion is consumed as hysteresis damping and viscous damping of the energy absorption damper, so the earthquake resistance is remarkably improved, and the main structure of the viaduct substructure, the ramen structure and brace material, is hardly damaged. Maintain soundness without being affected. Therefore, after the earthquake, the use of the railway viaduct can be continued as before by replacing the energy absorbing damper with a new one. In addition, a displacement design centering on the deformation performance of the energy absorbing damper is possible, and a more rational design is possible than a conventional design method that relies on a complicated RC deformation performance. Furthermore, by taking a reaction force from the brace material, it becomes possible to restore the residual deformation due to the earthquake of the ramen structure, and it is possible to easily control the damage during the earthquake.
[0095]
Further, according to the railroad viaduct substructure and the design method thereof according to the fifth and sixth aspects of the present invention, in addition to the function and effect of the fourth aspect, the railroad viaduct for the earthquake corresponding to the design acceleration is provided. There is also an effect that it is possible to reliably ensure traveling safety of a vehicle traveling on the vehicle while suppressing roll.
[0096]
[Brief description of the drawings]
FIG. 1 is a front view of a substructure of a viaduct according to a first embodiment viewed from a bridge axis direction.
FIG. 2 is a side view of the viaduct substructure according to the second embodiment viewed from a direction perpendicular to the bridge axis.
FIG. 3 is a cross-sectional view of a lower structure of a railway viaduct according to a third embodiment as viewed from the bridge axis direction.
FIG. 4 is a graph showing restoring force characteristics of the lower structure.
FIG. 5 is a graph showing the effect of the substructure of the railway viaduct according to the third embodiment.
FIG. 6 is a graph showing the effect of the substructure of the railway viaduct according to the third embodiment.
FIG. 7 is a design flowchart for designing a railway viaduct substructure according to a fourth embodiment.
FIG. 8 is a graph showing how to determine an excitation frequency of a traveling safety limit curve corresponding to a design excitation acceleration.
FIG. 9 is a front view of a lower structure of a viaduct according to the prior art as viewed from a bridge axis direction.
FIG. 10 is a construction diagram showing a procedure for constructing a viaduct substructure in the prior art.
[Explanation of symbols]
1 Foundation beam
2 orbit
5 Superstructure of viaduct
10, 21 Substructure of viaduct
11, 22 Columnar pier
12, 23 beams
13 Ramen structure
14, 24 Brace material
15, 25 Energy absorption damper
30 Viaduct substructure
31 Columnar Pier
32 beams
33 Ramen structure
34 Brace material
35 Energy absorption damper
37 Viaduct for railway

Claims (6)

  A ramen structure is formed from a pair of columnar piers erected at positions facing each other and a beam spanned on the top of the columnar pier, and an inverted V is formed in an in-plane space including the pair of columnar piers and the beam. A horizontal force is applied by arranging a brace material having a letter shape, joining the vicinity of the top of the brace material to the vicinity of the center of the beam, and joining both ends to the vicinity of the intermediate height position of the pair of columnar piers. A viaduct substructure which is configured so that deformation of the rigid frame structure can be suppressed by horizontal rigidity perpendicular to the bridge axis of the brace material without installing a foundation beam.   A ramen structure is formed from a columnar pier standing parallel to the bridge axis and a beam spanned on the top of the columnar pier, and among the columnar piers, an in-plane including a pair of adjacent columnar piers and the beam By arranging a brace material having an inverted V shape in the space, the brace material rigidity in the bridge axis direction of the brace material can be changed without installing a foundation beam when horizontal force in the bridge axis direction is applied. A viaduct substructure, characterized in that it can be suppressed.   The viaduct substructure according to claim 1 or 2, wherein a predetermined energy absorbing damper is interposed between the vicinity of the top of the brace material and the beam.   A ramen structure is formed from a pair of columnar piers erected at positions facing each other and a beam spanned on the top of the columnar pier, and an inverted V is formed in an in-plane space including the pair of columnar piers and the beam. A brace material having a letter shape is arranged, and the vicinity of the top of the brace material is joined to the vicinity of the center of the beam via a predetermined energy absorbing damper, and both ends are joined to the middle height position of the pair of columnar piers. A railroad viaduct substructure, wherein the railroad viaduct has a natural frequency in the direction orthogonal to the bridge axis of 2 Hz or more.   A ramen structure is formed from a pair of columnar piers erected at positions facing each other and a beam spanned on the top of the columnar pier, and an inverted V is formed in an in-plane space including the pair of columnar piers and the beam. A brace material having a letter shape is arranged, and the vicinity of the top of the brace material is joined to the vicinity of the center of the beam via a predetermined energy absorbing damper, and both ends are joined to the middle height position of the pair of columnar piers. The railroad viaduct substructure is a running safety curve group obtained by determining the relationship between the excitation frequency at the track laying position of the railroad viaduct and the lateral displacement amplitude of the track for each excitation acceleration. A driving safety limit curve that separates the safety area and the derailment area related to the performance is created, and the vibration frequency of the driving safety limit curve corresponding to the design excitation acceleration is obtained using the graph, Above Substructure railway viaduct, characterized in that the natural frequency of the bridge axis direction perpendicular viaduct for road is designed to be the pressurized oscillating frequency or more.   A ramen structure is formed from a pair of columnar piers erected at positions facing each other and a beam spanned on the top of the columnar pier, and an inverted V is formed in an in-plane space including the pair of columnar piers and the beam. A brace material having a letter shape is arranged, and the vicinity of the top of the brace material is joined to the vicinity of the center of the beam via a predetermined energy absorbing damper, and both ends are joined to the middle height position of the pair of columnar piers. A method for designing a substructure of a railway viaduct, comprising: a group of curves obtained by determining, for each excitation acceleration, a relationship between an excitation frequency at a track laying position of the railway viaduct and a lateral displacement amplitude of the track Is created by superimposing a travel safety limit curve that divides a safety region and a derailment region relating to travel safety, and using the graph, the vibration frequency of the travel safety limit curve corresponding to the design acceleration is designed. The Because, the design method of the lower structure of the railroad viaduct the natural frequency of the bridge axis perpendicular direction of the railway viaducts is characterized in that it designed to be the pressurized oscillating frequency or more.

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