JP2004092269A - Prevention structure for bridge fall and uplift in cable-stayed bridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize the prevention for bridge fall and uplift in the end supporting point section of a cable-stayed bridge without increasing weight of steel materials in a simple work. <P>SOLUTION: A cable insertion hole 20 with a middle section curved in an approximately circular arc-shape is so formed in the end cross beam 18 of a bridge girder 14 that both end sections thereof are opened in the lower surface 18a of the end cross beam 18 and the outside 18d in the direction of the bridge axis. An earthquake resistant cable 22 is inserted and placed in the cable insertion hole 20, and one end section 22a thereof is fixed to a vertical wall section 16A of an abutment 16 and, at the same time, the other end section 22b is fixed to a parapet section 16B of the abutment 16. Accordingly, reaction force of the parapet section 16B fixing the other end section 22b of the earthquake resistant cable 22 thereto is resisted to external force for the bridge girder 14 attributed to the bridge fall to make relative displacement inward in the direction of the bridge axis. Reaction force of the vertical wall section 16A fixing one end section 22a of the earthquake resistant cable 22 thereto is resisted to upper lift force acting on the bridge girder 14 attributed to the uplift. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a structure for preventing falling and lifting of a cable stayed bridge, that is, a structure for preventing a bridge girder from dropping from an abutment and lifting at an end fulcrum of a cable stayed bridge.
[0002]
In the specification of the present application, the concept of "cable-stayed bridge" includes not only an ordinary cable-stayed bridge but also an extra-dosed bridge.
[0003]
[Prior art]
Because a cable-stayed bridge is a suspended structure, an upward lift is likely to be generated on the bridge girder at the end fulcrum during a large-scale earthquake. If the upward lift is large, the bridge girder may rise from the abutment. Therefore, it is desirable to provide a lifting prevention structure at the end fulcrum of the cable stayed bridge.
[0004]
By the way, a bridge prevention structure for preventing a bridge from being dropped is often provided at an end fulcrum of the bridge. For example, Patent Literature 1 describes a fall prevention structure including a connecting member that connects an end cross beam and a chest wall of an abutment.
[0005]
If such a bridge prevention structure is provided, it is possible to expect a certain effect of lifting, but since the connecting member extends in the bridge axis direction, it acts on the end fulcrum of the cable stayed bridge. It is difficult to resist the large lifting forces that occur.
[0006]
On the other hand, if a structure in which the connecting members are arranged so as to extend in the vertical direction and connect the end cross beams and the vertical wall portion of the abutment is adopted as the lifting prevention structure, it acts on the end fulcrum portion of the cable stayed bridge. It is possible to resist a large lifting force.
[0007]
[Patent Document 1]
JP-A-2001-64914 (page 3, FIG. 1)
[Problems to be solved by the invention]
However, in such a case, since it is necessary to provide a lifting prevention structure separately from the falling bridge prevention structure, there is a problem that the work is troublesome and the weight of the steel material is increased.
[0008]
In particular, the end girder is difficult to secure the installation space for the fall prevention structure and the rise prevention structure because the structure tends to be complicated to fix the outer cable, etc., and the construction is troublesome. Problem.
[0009]
The present invention has been made in view of such circumstances, and can prevent the falling bridge and the lifting at the end fulcrum portion of the cable-stayed bridge with a simple construction without increasing the weight of the steel material. It is an object of the present invention to provide a structure for preventing falling and lifting of a cable stayed bridge.
[0010]
[Means for Solving the Problems]
The present invention is intended to achieve the above object by using a predetermined earthquake-resistant cable and devising a structure for inserting and arranging the cable.
[0011]
That is, the structure for preventing falling and lifting in the cable stayed bridge according to the present invention is as follows:
A structure for preventing a bridge girder from falling from an abutment and floating at an end fulcrum of a cable-stayed bridge,
A cable insertion hole having an intermediate portion curved in a substantially arc shape is formed in the end cross girder of the bridge girder so as to open both ends of the cable insertion hole to the lower surface of the end girder and the outer surface in the bridge axis direction. And
A predetermined earthquake-resistant cable is inserted and arranged in this cable insertion hole,
One end of the seismic cable is fixed to the vertical wall of the abutment, and the other end of the seismic cable is fixed to the parapet of the abutment.
[0012]
The above-mentioned “cable insertion hole” has a cross-sectional shape or an inside of the end cross beam if the middle portion is curved in a substantially arc shape and both ends are open to the lower surface of the end cross beam and the outer surface in the bridge axis direction. There are no particular restrictions on the specific configuration such as the formation position and the number of formations.
[0013]
The “predetermined earthquake-resistant cable” is not particularly limited in its material, cross-sectional shape, etc., as long as it has sufficient tensile strength to prevent the bridge girder from falling and floating.
[0014]
Operation and Effect of the Invention
As shown in the above configuration, the structure for preventing falling and lifting of the cable-stayed bridge according to the present invention includes a cable insertion hole whose middle portion is curved in a substantially arc shape in an end horizontal girder of the bridge girder, and the both ends of the cable girder are horizontal. It is formed so as to open to the lower surface of the girder and the outer surface in the bridge axis direction, and an earthquake-resistant cable is inserted and arranged in this cable insertion hole, one end of which is fixed to the vertical wall portion of the abutment. Since the other end is fixed to the chest wall of the abutment, the following operation and effect can be obtained.
[0015]
In other words, the external force that causes the bridge girder to relatively displace the bridge girder inward in the bridge axis direction can be resisted by the reaction force of the chest wall where the other end of the seismic cable is fixed, and The upward lift acting on the bridge girder, which causes the bridge girder, can be resisted by the reaction force of the vertical wall to which one end of the seismic cable is fixed.
[0016]
And simply by inserting the seismic cable inside the end cross beam, the bridge prevention function and the lifting prevention function can be obtained at the same time, so the bridge prevention structure and the lifting prevention structure are separately provided. Compared with the case, the construction can be simplified, and the weight of the steel material can be reduced.
[0017]
As described above, according to the present invention, it is possible to prevent the bridge from falling and the floating at the end fulcrum portion of the cable-stayed bridge without increasing the weight of the steel material and by simple construction. Thus, the construction cost can be reduced.
[0018]
In the above configuration, the earthquake-resistant cable includes a first cable having one end fixed to the vertical wall portion and the other end fixed to the outer surface of the cross beam in the bridge axis direction, and one end connected to the other end of the first cable. If the second cable is connected and fixed and the other end is fixed to the outer surface of the chest wall in the bridge axis direction, the second cable is constructed after the construction of the first cable is completed. Therefore, the handling of the earthquake-resistant cable is facilitated, so that the workability can be further improved.
[0019]
In the above configuration, as described above, the specific configuration of the cable insertion hole is not particularly limited. However, the portion near the lower surface of the end cross beam in the cable insertion hole is directed toward the lower surface of the end cross beam on both sides in the bridge axis direction. If the bridge girder is relatively displaced to some extent in the bridge axis direction, the seismic cable will be damaged by the shearing action between the end girder and the vertical wall or the interference between the seismic cable and the end girder. It is possible to eliminate the risk of doing so.
[0020]
Further, in the above configuration, if the middle portion of the cable insertion hole is formed of a metal tube buried in the end cross beam, most of the load acting on the wall surface of the cable insertion hole from the seismic cable can be received by the metal tube. Thus, the insertion support strength for the earthquake-resistant cable can be increased. In addition, with such a configuration, concrete can be cast in the lateral girder in a state where the earthquake-resistant cable has been inserted and arranged in the cable insertion hole in advance, and the workability can be further improved.
[0021]
In this case, if the metal pipe is configured such that the half pipes divided into two in the direction orthogonal to the bridge axis are joined to each other, both ends of the earthquake-resistant cable are formed with a diameter larger than that of the general part therebetween. Also in this case, the seismic cable can be easily inserted into the metal tube by joining the general portion while sandwiching the general portion with the half-pipe from both sides.
[0022]
In addition, if an elastic ring is attached to the inner peripheral surface of the lower end opening of the metal pipe, even if the bridge girder is displaced to some extent in the bridge axis direction, the seismic cable will not contact the lower end opening of the metal pipe. It can be prevented from being easily damaged by contact.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0024]
FIG. 1 is a cross-sectional view at right angles to the bridge axis, showing a structure for preventing falling and lifting of a cable-stayed bridge according to an embodiment of the present invention, and FIG. 2 is a detailed cross-sectional view taken along line II-II of FIG. FIG. 1 is a cross-sectional view taken along a line II in FIG.
[0025]
As shown in these drawings, the falling bridge and lifting prevention structure according to the embodiment is a structure for preventing the bridge girder 14 from dropping from the abutment 16 and lifting at the end fulcrum of the cable stayed bridge 10.
[0026]
As shown in FIG. 1, the bridge girder 14 is supported on an abutment 16 via a pair of seismic isolation bearings 12 at an end cross girder 18 located at the end fulcrum. Each of the seismic isolation bearings 12 is disposed so as to be sandwiched between the lower surface 18 a of the end cross beam 18 and the upper surface 16 a of the vertical wall portion 16 of the abutment 16.
[0027]
A structure is provided between the seismic isolation bearings 12 to prevent the bridge girder 14 from being displaced relative to the abutment 16 in a direction orthogonal to the bridge axis. That is, at the center of the lower surface 18a of the end cross beam 18 in the direction perpendicular to the bridge axis, a projection 18b for preventing displacement is formed which protrudes downward. On the upper surface 16a of the vertical wall portion 16A of the abutment 16, a pair of displacement prevention protrusions 16b are formed so as to sandwich the displacement prevention protrusion 18b from both sides in the direction orthogonal to the bridge axis. In addition, a manhole 18c is formed above the prevention protrusion 18b at the center of the end cross beam 18 in the direction orthogonal to the bridge axis.
[0028]
In the structure for preventing falling and lifting according to the present embodiment, an earthquake-resistant cable 22 is inserted and arranged in each of the cable insertion holes 20 formed at four locations of the end cross beams 18. Two of these four cable insertion holes 20 are provided at each position of the pair of projections 16b for preventing displacement.
[0029]
As shown in FIG. 2, each cable insertion hole 20 is formed such that an intermediate portion thereof is curved in a substantially arc shape, and both ends thereof are opened at the lower surface 18 a of the end cross beam 18 and the outer surface 18 d in the bridge axis direction. It is formed so that.
[0030]
One end 22a of the seismic cable 22 inserted into each of the cable insertion holes 20 is fixed to the vertical wall 16A of the abutment 16, and the other end 22b is fixed to the chest wall 16B of the abutment. At this time, in each of the earthquake-resistant cables 22, a first cable 22A and a second cable 22B are connected and fixed to each other in a series arrangement. FIG. 3 is a diagram illustrating a state where the construction of the first cable 22A has been completed and the construction of the second cable 22B has not been performed yet.
[0031]
As shown in FIG. 3, the first cable 22A has a configuration in which one end 22Aa is fixed to the vertical wall portion 16A and the other end 22Ab is fixed to the bridge shaft direction outer surface 18d of the end cross beam 18. Has become. On the other hand, the second cable 22B has one end 22Ba connected and fixed to the other end 22Ab of the first cable 22A, and the other end 22Bb fixed to the bridge shaft direction outer surface 16c of the chest wall 16B.
[0032]
An intermediate portion of the cable insertion hole 20 is constituted by a metal tube 24 buried in the end cross beam 18.
[0033]
The metal tube 24 is a steel member formed so as to be curved in a quarter arc shape. Half tubes 24A and 24B divided into two in the direction orthogonal to the bridge axis are joined to each other by a plurality of bolts 26. It has been. An elastic ring 28 made of chloroprene sponge is mounted on the inner peripheral surface of the lower end opening 24a of the metal tube 24.
[0034]
Below the lower end opening 24a of the metal tube 24, there is provided a steel box removing member 30 extending to the lower surface 18a of the end cross beam 18 so as to be connected to the lower end opening 24a. The box removing member 30 has a rectangular horizontal cross section and a trapezoidal side cross section. Thus, the portion of the cable insertion hole 20 near the lower surface of the end cross beam 18 is formed so as to expand toward both sides in the bridge axis direction toward the lower surface 18a of the end cross beam 18.
[0035]
On the other hand, an anchor plate 32 with a steel pipe is provided outside the upper end opening of the metal pipe 24 in the direction of the bridge axis so as to be connected to the upper end opening and extends to the outer surface 18d of the end cross beam 18 in the bridge axis direction. I have.
[0036]
The cable insertion hole 20 is formed by laying concrete on the end cross beam 18 in a state where the metal pipe 24, the box punching member 30, and the steel plate anchor plate 32 are arranged in series. . At this time, a reinforcing spiral reinforcing bar 34 is buried around the metal tube 24, and a reinforcing reinforcing bar 36 is buried around the anchor plate 32 with the steel tube. Further, this concrete casting is performed in a state where the first cable 22A is inserted and arranged in the cable insertion hole 20 in advance.
[0037]
The first cable 22A is formed to be relatively long, and each end 22Aa, 22Ab is formed of a threaded steel apartment. On the other hand, the second cable 22B is formed to be relatively short, and each end 22Ba, 22Bb is also formed of a threaded steel apartment.
[0038]
At a position below the lower end opening 24a of the metal tube 24 in the vertical wall portion 16A, a trumpet sheath 38 that opens on the upper surface 16a of the vertical wall portion 16A (the position preventing protrusion 16b) is connected to the trumpet sheath 38. Anchor plate 40 with a steel pipe arranged so as to be fixed, a nut 42 fixed to the lower end of the anchor plate 40 with a steel pipe, and a steel plate fixed to the anchor plate 40 with a steel pipe so as to cover the nut 42 The cap 44 and the cap 44 are embedded so as to extend in the vertical direction, and a reinforcing reinforcing bar 46 is embedded around the anchor plate 40 with the steel pipe.
[0039]
Then, the fixing of the first cable 22A to the vertical wall 16A at the one end 22Aa is performed by inserting the one end 22Aa of the first cable 22A into the steel plate anchor plate 40 via the trumpet sheath 38 and tightening the nut 42 with the screw. This is done by fixing.
[0040]
On the other hand, in order to fix the end cross beam 18 at the other end 22Ab of the first cable 22A to the outer surface 18d in the bridge axis direction, a nut 48 is attached to the other end 22Ab of the first cable 22A protruding from the outer surface 18d in the bridge axis direction. Then, the nut 48 is screwed and fixed to the anchor plate 32 with steel pipe.
[0041]
A trumpet sheath 52 that opens in the bridge axis direction inner surface of the chest wall portion 16B and a guide pipe that is arranged so as to be connected to the trumpet sheath 52 are provided on the chest wall portion 16B at a position outside the bridge plate-attached anchor plate 32 in the bridge axis direction. 54 are embedded so as to extend in the bridge axis direction, and a reinforcing reinforcing bar 56 is embedded around the guide pipe 54.
[0042]
The connection and fixing of the first cable 22A to the other end 22Ab of the first cable 22A at the one end 22Ba of the second cable 22B is performed by connecting the connecting tool 58 having a thread formed on the inner peripheral surface to the other end 22Ab of the first cable 22A. And one end 22Ba of the second cable 22B. An elastic sheath 50 that covers the earthquake-resistant cable 22 is provided between the end cross beam 18 and the chest wall 16B.
[0043]
On the other hand, the other end 22Bb of the second cable 22B is fixed to the chest wall 16B at the other end 22Bb by inserting the other end 22Bb of the second cable 22B into the guide pipe 54 via the trumpet sheath 52 and connecting the bridge shaft of the chest wall 16B. This is performed by projecting from the directional outer surface 16c, attaching a nut 62 to the other end portion 22Bb via a spring 60, and screwing the nut 62 to the bridge shaft directional outer surface 16c. At this time, a buffer 64 made of a buffer packing and a support plate is interposed between the spring 60 and the chest wall 16B, and a stop plate 66 is interposed between the spring 60 and the nut 62. It has become. A steel cap 68 that covers the other end 22Bb of the second cable 22B is attached to the bridge axial direction outer surface 16c of the chest wall 16B.
[0044]
FIG. 4 is a view showing a state in which the bridge girder 14 is displaced inward in the bridge axis direction with respect to the abutment 16.
[0045]
As shown in the drawing, when the bridge girder 14 is relatively displaced inward in the bridge axis direction, a tensile load accompanying the relative displacement acts on the second cable 22B of the earthquake-resistant cable 22. Absorbed by deformation.
[0046]
On the other hand, when the bridge girder 14 is relatively displaced inward in the bridge axis direction, the portion of the first cable 22A of the earthquake-resistant cable 22 between the lower end opening 24a of the metal tube 24 and the anchor plate 40 with the steel tube is perpendicular to the vertical direction. As a result, a tensile load acts on the first cable 22A. At this time, since the nut 48 attached to the other end 22Ab of the first cable 22A is in contact with the outer surface 18d of the end cross beam 18 in the bridge axis direction, the tensile load acting on the first cable 22A is Although it is not absorbed by the compressive deformation, the tensile load acting on the first cable 22A at this time is relatively small, so that no further trouble occurs.
[0047]
When the bridge girder 14 is further displaced inward in the bridge axis direction with respect to the abutment 16 and the amount of elastic compressive deformation of the spring 60 reaches the limit, a large tensile load acts on the entire length of the earthquake-resistant cable 22. At this time, the further displacement of the bridge girder 14 is restricted by the reaction force of the chest wall portion 16B, thereby preventing the bridge girder 14 from dropping from the abutment 16 beforehand.
[0048]
As described above, due to the relative displacement of the bridge girder 14 inward in the bridge axis direction, the portion between the lower end opening 24a of the metal pipe 24 and the steel plate anchor plate 40 in the first pipe 22A is perpendicular to the vertical direction. Although it is inclined, the portion near the lower surface of the end cross beam 18 in the cable insertion hole 20 is formed so as to expand on both sides in the bridge axis direction toward the lower surface 18a of the end cross beam 18 by the box punching member 30. There is no risk that the first cable 22A will be damaged due to interference with the box removing member 30, and that the first cable 22A will not be damaged due to the shearing action between the end cross beam 18 and the vertical wall portion 16A. . In addition, since the elastic ring 28 is attached to the inner peripheral surface of the lower end opening 24a of the metal tube 24, there is no possibility that the first cable 22A abuts on the lower end opening 24a of the metal tube 24 and is damaged. .
[0049]
Even if the first cable 22A is inclined with respect to the vertical direction in this way, the abutment between the first cable 22A and the vertical wall portion 16A takes a predetermined length due to the trumpet sheath 38 provided on the vertical wall portion 16A. Since this is performed, there is no possibility that the first cable 22A is damaged by interference with the vertical wall portion 16A.
[0050]
On the other hand, when an upward lift is applied to the bridge girder 14, a large tensile load is applied to the first cable 22A, and the lift of the bridge girder 14 is regulated by the reaction force of the vertical wall 16A to which one end 22Aa is fixed. At this time, even if the bridge girder 14 is slightly displaced upward, a clearance is secured between the second cable 22B and the chest wall 16B by the trumpet sheath 52 provided on the chest wall 16B. Is not likely to be damaged by interference with the chest wall portion 16B.
[0051]
As described in detail above, in the present embodiment, the cable insertion hole 20 whose middle portion is curved in a substantially arc shape is provided in the end cross girder 18 of the bridge girder 14, and the lower end 18 a of the end cross girder 18 at both ends thereof. An anti-seismic cable 22 is inserted through the cable insertion hole 20, and one end 22 a thereof is fixed to the vertical wall portion 16 A of the abutment 16. Further, since the other end 22b is fixed to the chest wall 16B of the abutment 16, the following operation and effect can be obtained.
[0052]
In other words, the external force that causes the bridge girder 14 to be relatively displaced inward in the bridge axis direction, which causes the falling bridge, can be resisted by the reaction force of the chest wall 16B to which the other end 22b of the seismic cable 22 is fixed. In addition, the vertical lift 16A to which the one end 22a of the seismic cable 22 is fixed can be resisted against the upward lift acting on the bridge girder 14 which causes the lifting.
[0053]
By simply inserting the seismic cable 22 in the end cross beam 18 in this manner, the bridge prevention function and the lifting prevention function can be obtained at the same time. Therefore, the bridge prevention structure and the lifting prevention structure are provided separately. As compared with the case of the above, the construction can be simplified, and the weight of the steel material can be reduced. Thus, the construction cost can be reduced.
[0054]
In particular, in the present embodiment, the earthquake-resistant cable 22 includes a first cable 22A having one end 22Aa fixed to the vertical wall portion 16A and the other end 22Ab fixed to the bridge axis direction outer surface 18d of the end cross beam 18; One end 22B is connected and fixed to the other end 22Ab of the first cable 22A, and the second cable 22B has the other end 22Bb fixed to the bridge shaft direction outer surface 16Ba of the chest wall 16B. After completing the construction of the first cable 22A, the construction of the second cable 22B can be performed. Therefore, the handling of the earthquake-resistant cable 22 is facilitated, and the workability can be further improved.
[0055]
In the present embodiment, the portion near the lower surface of the end cross beam 18 in the cable insertion hole 20 is formed by the box punching member 30 so as to expand on both sides in the bridge axis direction toward the lower surface 18a of the end cross beam 18. Even when the bridge girder 14 is relatively displaced in the bridge axis direction to some extent, the seismic cable 22 is damaged by the shearing action between the end cross girder 18 and the vertical wall portion 16A or the interference action between the seismic cable 22 and the end cross girder 18. It is possible to eliminate the risk of being lost.
[0056]
Further, in the present embodiment, since the middle portion of the cable insertion hole 20 is constituted by the metal tube 24 buried in the end cross beam 18, the load acting on the wall surface of the cable insertion hole 20 from the seismic cable 22 is reduced. Most can be received by the metal tube 24, which can increase the insertion support strength for the earthquake-resistant cable 22. Moreover, with this configuration, concrete can be cast on the end cross beams 18 in a state where the earthquake-resistant cable 22 has been inserted and arranged in the cable insertion hole 20 in advance, thereby further improving workability. Can be.
[0057]
Since the metal tube 24 is formed by joining the half tubes 24A and 24B divided into two in the direction orthogonal to the bridge axis, both ends 22Aa and 22Ab of the first cable 22A have a larger diameter than the general portion therebetween. However, the first cable 22A can be inserted into the metal tube 24 by joining the general portion while sandwiching the general portion between the half tubes 24A and 24B.
[0058]
In addition, since the elastic ring 28 is attached to the inner peripheral surface of the lower end opening 24a of the metal tube 24, even when the bridge girder 14 is relatively displaced to some extent in the bridge axis direction, the anti-seismic cable 22 is connected to the metal tube 24. It is possible to prevent the lower end opening 24a from being easily damaged by contact with the lower end opening 24a.
[0059]
In the present embodiment, the earthquake-resistant cable 22 has a configuration in which the first cable 22A and the second cable 22B are connected and fixed from the viewpoint of further improving the workability. Of course, it may be done.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view orthogonal to a bridge axis, showing a structure for preventing a bridge from being lifted and rising in a cable-stayed bridge according to an embodiment of the present invention. FIG. 2 is a detailed cross-sectional view taken along the line II-II of FIG. FIG. 4 is a view similar to FIG. 2 showing the lifting prevention structure in a state where the construction of the first cable has been completed and the construction of the second cable has not yet been performed. FIG. 4 shows the falling bridge and the lifting prevention structure. Diagram similar to FIG. 2 showing a state of relative displacement inward in the axial direction.
DESCRIPTION OF SYMBOLS 10 Cable-stayed bridge 12 Seismic isolation bearing 14 Bridge girder 16 Abutment 16A Vertical wall part 16B Parapet wall part 16a Upper surface 16b Displacement prevention protrusion 16c Bridge axial direction outer surface 18 End girder 18a Lower surface 18b Displacement prevention protrusion 18c Manhole 18d Bridge Axial outer surface 20 Cable insertion hole 22 Seismic cable 22A First cable 22B Second cable 22a, 22Aa, 22Aa One end 22b, 22Ab, 22Bb The other end 24 Metal tube 24A, 24B Half tube 24a Lower end opening 26 Bolt 28 Elasticity Ring 30 Box removal member 32, 40 Anchor plate with steel pipe 34 Reinforced spiral rebar 36, 46, 56 Reinforcing rebar 38, 52 Trumpet sheath 42, 48, 62 Nut 44, 68 Steel cap 50 Telescopic sheath 54 Guide pipe 58 Connector 60 Spring 64 Buffer 66 Stopper Over door

Claims (6)

A structure for preventing a bridge girder from falling from an abutment and floating at an end fulcrum of a cable-stayed bridge,
A cable insertion hole having an intermediate portion curved in a substantially arc shape is formed in the end cross girder of the bridge girder so as to open both ends of the cable insertion hole to the lower surface of the end girder and the outer surface in the bridge axis direction. And
A predetermined earthquake-resistant cable is inserted and arranged in this cable insertion hole,
An end of the seismic cable is fixed to the vertical wall of the abutment, and the other end of the seismic cable is fixed to the parapet of the abutment. Prevention structure. A first cable having one end fixed to the vertical wall portion and the other end fixed to the outer surface of the cross beam in the bridge axis direction; and one end connected to the other end of the first cable. The cable-stayed bridge according to claim 1, further comprising a second cable fixedly connected and having a second end fixed to the outer surface of the chest wall in the bridge axis direction. The oblique portion according to claim 1 or 2, wherein a portion of the cable insertion hole near a lower surface of the end cross beam is formed so as to expand on both sides in the bridge axis direction toward the lower surface of the end cross beam. Prevention of falling bridges and uplifts on the stayed bridge. 4. The structure for preventing a cable-stayed bridge from falling and lifting according to any one of claims 1 to 3, wherein an intermediate portion of the cable insertion hole is formed of a metal tube embedded in the end cross beam. 5. The structure for preventing falling and lifting of a cable-stayed bridge according to claim 4, wherein said metal pipe is divided into two half-split pipes in the direction orthogonal to the bridge axis. The structure for preventing falling and rising of a cable-stayed bridge according to claim 4 or 5, wherein an elastic ring is attached to an inner peripheral surface of a lower end opening of the metal tube.

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