JP3913647B2 - Falling bridge and floating prevention structure in cable-stayed bridge - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a falling bridge and a floating prevention structure in a cable-stayed bridge, that is, a structure for preventing the bridge girder from falling off the abutment and floating at the end fulcrum portion of the cable-stayed bridge.
[0002]
In the present specification, the concept of “cable stayed bridge” includes not only ordinary cable stayed bridges but also extradosed bridges.
[0003]
[Prior art]
The cable-stayed bridge is a suspended structure, so when a large-scale earthquake occurs, it is easy for lift force to occur at the bridge girder at the end fulcrum. When the lifting force is large, the bridge girder may be lifted from the abutment. Therefore, it is desirable to provide a floating prevention structure at the end fulcrum portion of the cable-stayed bridge.
[0004]
By the way, the end fulcrum portion of the bridge is often provided with a fall prevention structure for preventing a fall bridge. For example, “Patent Document 1” describes a falling bridge prevention structure including a connecting member that connects an end cross beam and a chest wall of an abutment.
[0005]
When such a fall-bridge prevention structure is provided, it is possible to expect a little lift-up prevention effect, but the connecting member extends in the bridge axis direction, so that it acts on the end fulcrum of the cable-stayed bridge. It is difficult to resist the large uplift force.
[0006]
On the other hand, if the structure that connects the end cross girder and the abutment wall is adopted as a structure to prevent the lift from extending in the vertical direction, it acts on the end fulcrum of the cable-stayed bridge. It is possible to resist a large lifting force.
[0007]
[Patent Document 1]
JP 2001-64914 A (page 3, FIG. 1)
[Problems to be solved by the invention]
However, in this case, there is a problem that it is necessary to provide a lifting prevention structure separately from the falling bridge prevention structure, which requires troublesome construction and increases the weight of the steel material.
[0008]
In particular, the structure of the end cross girders is likely to be complicated due to the fixing of the outer cable, etc., so it is not easy to secure the installation space for the falling bridge prevention structure and the lifting prevention structure, and the construction thereof becomes troublesome. There is a problem that.
[0009]
The present invention has been made in view of such circumstances, and can prevent the falling bridge and the floating prevention at the end fulcrum of the cable-stayed bridge without increasing the weight of the steel material and by simple construction. An object of the present invention is to provide a structure for preventing falling and lifting of cable-stayed bridges.
[0010]
[Means for Solving the Problems]
In the present invention, a predetermined seismic cable is used and the insertion and arrangement structure is devised to achieve the above object.
[0011]
That is, the falling bridge and the floating prevention structure in the cable stayed bridge according to the present invention are:
A structure for preventing the bridge girder from falling off the abutment and floating at the end fulcrum of the cable stayed bridge,
A cable insertion hole whose middle part is curved in a substantially arc shape is formed in the end cross girder of the bridge girder so that both ends of the cable insertion hole are opened to the lower surface of the end cross girder and the outer surface in the bridge axial direction. And
A predetermined seismic cable is inserted into this cable insertion hole,
One end of the seismic cable is fixed to the abutment wall of the abutment, and the other end of the seismic cable is fixed to the chest wall of the abutment.
[0012]
The above-mentioned “cable insertion hole” has a cross-sectional shape or an inside of the end cross beam as long as 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]
As long as the “predetermined earthquake resistant cable” has sufficient tensile strength to prevent the bridge girder from dropping and lifting, the specific configuration such as the material and the cross-sectional shape thereof is not particularly limited.
[0014]
[Effects of the invention]
As shown in the above configuration, in the cable-stayed bridge according to the present invention, the falling bridge and the floating prevention structure include a cable insertion hole whose middle portion is curved in a substantially arc shape in the end girder of the bridge girder. It is formed so as to open to the lower surface of the girder and the outer surface in the bridge axial direction, and an earthquake-resistant cable is inserted into this cable insertion hole, and one end of the cable is fixed to the wall of the abutment Since the other end is fixed to the chest wall of the abutment, the following effects can be obtained.
[0015]
That is, the external force that causes the bridge girder to be displaced relatively inward in the axial direction of the bridge can be resisted by the reaction force of the chest wall to which the other end of the seismic cable is anchored. It is possible to resist the lifting force acting on the bridge girder that is caused by the reaction force of the anchor wall portion to which one end of the earthquake-resistant cable is fixed.
[0016]
And, just by inserting and arranging the earthquake-resistant cable in the end cross girder in this way, it is possible to obtain the fall prevention function and the rise prevention function at the same time, so the fall prevention structure and the rise prevention structure are provided separately. As 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 falling bridge and the floating prevention at the end fulcrum portion of the cable-stayed bridge without increasing the weight of the steel material and by simple construction. And thereby, construction cost can be reduced.
[0018]
In the above-described configuration, the seismic cable includes a first cable having one end fixed to the anchor wall and the other end fixed to the outer surface of the end cross beam in the bridge axis direction, and one end to the other end of the first cable. If the second cable having the other end fixed to the outer surface in the bridge axis direction of the chest wall portion is connected and fixed, the second cable is installed after the first cable is completed. Therefore, the handling of the earthquake-resistant cable becomes easy, and thereby the workability can be further improved.
[0019]
In the above configuration, the specific configuration of the cable insertion hole is not particularly limited, as described above, but the portion near the lower surface of the end cross beam in the cable insertion hole faces both sides in the bridge axis direction toward the lower surface of the end cross beam. If the bridge girder is formed so as to spread out, even if the bridge girder is relatively displaced in the direction of the bridge axis, the seismic cable is damaged by the shearing action between the end cross girder and the anchor wall or by the interference action between the seismic cable and the end cross girder The risk of doing so can be eliminated.
[0020]
Also, in the above configuration, if the middle part of the cable insertion hole is made of a metal tube embedded in the end cross beam, most of the load acting on the wall surface of the cable insertion hole can be received from the earthquake resistant cable by the metal tube. In addition, the insertion support strength for the earthquake resistant cable can be increased. In addition, by configuring in this way, it is possible to perform the concrete placement of the end cross girders in a state in which the earthquake-proof cable is inserted and disposed in the cable insertion hole in advance, and thereby the workability can be further improved.
[0021]
In this case, if the metal pipe has a structure in which the half pipes divided into two in the direction perpendicular to the bridge axis are joined to each other, both ends of the earthquake-resistant cable are formed with a larger diameter than the general part therebetween. Even in such a case, the seismic cable can be easily inserted into the metal pipe by joining the general part with the half pipe sandwiched from both sides.
[0022]
In addition, if the elastic ring is attached to the inner peripheral surface of the lower end opening of the metal pipe, the seismic cable contacts the lower end opening of the metal pipe even when the bridge girder is displaced to some extent in the direction of the bridge axis. It is possible to prevent the contact and easy damage.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0024]
FIG. 1 is a cross-sectional view orthogonal to a bridge axis showing a falling bridge and a floating prevention structure in a cable-stayed bridge according to an embodiment of the present invention, and FIG. 2 is a detailed cross-sectional view taken along the line II-II in FIG. 1 is a cross-sectional view taken along the line II in FIG.
[0025]
As shown in these drawings, the falling bridge and the floating prevention structure according to the embodiment is a structure for preventing the bridge girder 14 from dropping from the abutment 16 and floating at the end fulcrum portion of the cable-stayed bridge 10.
[0026]
As shown in FIG. 1, the bridge girder 14 is supported by the abutment 16 via a pair of seismic isolation bearings 12 at an end cross girder 18 located at the end fulcrum portion. 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 bridge wall 16 of the abutment 16.
[0027]
A structure for preventing the bridge girder 14 from being displaced in a direction perpendicular to the bridge axis with respect to the abutment 16 is provided between the two seismic isolation bearings 12. That is, a misalignment preventing projection 18b that protrudes downward is formed at the center of the lower surface 18a of the end cross beam 18 in the direction perpendicular to the bridge axis. In addition, a pair of misalignment preventing projections 16b are formed on the upper surface 16a of the anchor wall 16A of the abutment 16 so as to sandwich the misalignment preventing projections 18b from both sides in the direction perpendicular to the bridge axis. A manhole 18c is formed in the upper part of the protrusion 18b for prevention in the central part of the end cross beam 18 in the direction perpendicular to the bridge axis.
[0028]
In the falling bridge and the floating prevention structure according to the present embodiment, the earthquake-resistant cable 22 is inserted and arranged in each of the cable insertion holes 20 formed at the four positions of the end cross beam 18. Two of these four cable insertion holes 20 are provided at each position of the pair of misalignment prevention protrusions 16b.
[0029]
As shown in FIG. 2, each cable insertion hole 20 is formed so that the middle portion thereof is curved in a substantially arc shape, and both end portions thereof are opened to the lower surface 18a of the end cross beam 18 and the bridge axial direction outer surface 18d. It is formed to do.
[0030]
One end portion 22a of the seismic cable 22 inserted and arranged in each cable insertion hole 20 is fixed to the heel wall portion 16A of the abutment 16, and the other end portion 22b is fixed to the chest wall portion 16B of the abutment. At this time, each of the seismic cables 22 has the first cable 22A and the second cable 22B connected and fixed to each other in series. FIG. 3 is a diagram illustrating a state in which the construction of the first cable 22A is completed and the construction of the second cable 22B is not yet performed.
[0031]
As shown in FIG. 3, the first cable 22A has a configuration in which one end 22Aa is fixed to the wall 16A and the other end 22Ab is fixed to the bridge axial direction outer surface 18d of the end cross beam 18. It has become. On the other hand, one end 22Ba of the second cable 22B is connected and fixed to the other end 22Ab of the first cable 22A, and the other end 22Bb is fixed to the outer surface 16c in the bridge axis direction of the chest wall 16B.
[0032]
An intermediate portion of the cable insertion hole 20 is composed of a metal tube 24 embedded in the end cross beam 18.
[0033]
The metal tube 24 is a steel member formed to be curved in a quarter arc shape, and the 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 done. An elastic ring 28 made of chloroprene sponge is attached to 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, a steel boxing 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 is provided. The boxing member 30 has a rectangular horizontal cross section and a trapezoidal side cross section. Thereby, the lower surface vicinity part of the end cross beam 18 in the cable insertion hole 20 is formed so as to spread toward the lower surface 18a of the end cross beam 18 on both sides in the bridge axis direction.
[0035]
On the other hand, an anchor plate 32 with a steel pipe is provided on the outer side in the bridge axis direction of the upper end opening of the metal pipe 24 and extends to the bridge axis direction outer surface 18d of the end cross beam 18 so as to be connected to the upper end opening. Yes.
[0036]
And the cable penetration hole 20 is formed by performing concrete placement of the end cross girder 18 in the state where these metal pipe 24, box extraction member 30, and anchor plate 32 with a steel pipe are arranged in series. . At that time, a reinforcing spiral reinforcing bar 34 is embedded around the metal tube 24, and a reinforcing reinforcing bar 36 is embedded around the anchor plate 32 with steel pipe. Further, the concrete placement 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 steel apartment with a thread. On the other hand, the 2nd cable 22B is formed in comparatively short length, and each end part 22Ba and 22Bb is also comprised by the steel condominium with a thread.
[0038]
A trumpet sheath 38 that opens to the upper surface 16a of the heel wall portion 16A (the misalignment prevention projection portion 16b) is connected to the trumpet sheath 38 at a position below the lower end opening portion 24a of the metal tube 24 in the heel wall portion 16A. The steel pipe anchor plate 40 arranged as described above, the nut 42 fixed to the lower end of the steel pipe anchor plate 40, and the steel pipe fixed to the steel pipe anchor plate 40 so as to cover the nut 42 A cap 44 is embedded so as to extend in the vertical direction, and a reinforcing steel bar 46 is embedded around the anchor plate 40 with steel pipe.
[0039]
The fixing of the first cable 22A to the flange wall portion 16A at the one end portion 22Aa is performed by inserting the one end portion 22Aa of the first cable 22A into the anchor plate 40 with a steel pipe via the trumpet sheath 38 and screwing the nut 42 to the nut 42. It is done by fixing.
[0040]
On the other hand, fixing the end cross beam 18 to the outer surface 18d in the bridge axial direction at the other end 22Ab of the first cable 22A attaches a nut 48 to the other end 22Ab of the first cable 22A protruding from the outer surface 18d in the bridge axial direction. The nut 48 is fixed to the anchor plate 32 with steel pipe by screwing.
[0041]
A trumpet sheath 52 that opens to the inner surface in the bridge axis direction of the chest wall portion 16B and a guide pipe that is arranged so as to be connected to the trumpet sheath 52 are located at an outer position in the bridge axis direction of the anchor plate 32 with steel pipe in the chest wall portion 16B. 54 is embedded so as to extend in the direction of the bridge axis, and reinforcing reinforcing bars 56 are embedded around the guide pipe 54.
[0042]
Then, the connection and fixing of the first cable 22A to the other end 22Ab of the first cable 22B at the one end 22Ba of the second cable 22B is performed by connecting the connector 58 having a thread formed on the inner peripheral surface to the other end 22Ab of the first cable 22A. And one end portion 22Ba of the second cable 22B. In addition, the expansion-contraction sheath 50 which covers the earthquake-resistant cable 22 is provided between the end cross beam 18 and the chest wall part 16B.
[0043]
On the other hand, fixing to the chest wall portion 16B at the other end portion 22Bb of the second cable 22B is performed by inserting the other end portion 22Bb of the second cable 22B into the guide pipe 54 via the trumpet sheath 52 to bridge the chest wall portion 16B. This is performed by projecting from the outer surface 16c in the direction, attaching a nut 62 to the other end 22Bb via a spring 60, and screwing and fixing the nut 62 to the outer surface 16c in the bridge axis direction. At that time, a shock absorber 64 including a shock absorbing packing and a pressure bearing plate is interposed between the spring 60 and the chest wall portion 16B, and a stopper plate 66 is interposed between the spring 60 and the nut 62. It has become. And the steel cap 68 which covers the other end part 22Bb of the 2nd cable 22B is attached to the bridge-axis direction outer surface 16c of the chest wall part 16B.
[0044]
FIG. 4 is a diagram illustrating 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 figure, when the bridge girder 14 is relatively displaced inward in the bridge axial direction, a tensile load due to the relative displacement acts on the second cable 22B of the earthquake-resistant cable 22, and this tensile load is elastically compressed by the spring 60. Absorbed by deformation.
[0046]
On the other hand, in the first cable 22A of the earthquake-resistant cable 22, when the bridge girder 14 is relatively displaced inward in the bridge axial direction, the portion between the lower end opening 24a of the metal pipe 24 and the anchor plate 40 with steel pipe is perpendicular to the vertical direction. Accordingly, a tensile load acts on the first cable 22A. At that time, since the nut 48 attached to the other end portion 22Ab of the first cable 22A is in contact with the bridge axial direction outer surface 18d of the end cross beam 18, the tensile load acting on the first cable 22A is elastic of the spring 60. 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 other trouble occurs.
[0047]
When the bridge girder 14 is further displaced inward in the bridge axial direction with respect to the abutment 16 and the amount of elastic compression 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 beam 14 is restricted by the reaction force of the chest wall portion 16B, thereby preventing the bridge beam 14 from dropping from the abutment 16 in advance.
[0048]
As described above, due to the relative displacement of the bridge girder 14 inward in the bridge axis direction, the first cable 22A has a portion between the lower end opening 24a of the metal pipe 24 and the anchor plate 40 with steel pipe with respect to the vertical direction. Although it is in an inclined state, the portion near the lower surface of the end cross beam 18 in the cable insertion hole 20 is formed so as to spread on both sides in the bridge axis direction toward the lower surface 18a of the end cross beam 18 by the box removing member 30. There is no possibility that the first cable 22A will be damaged by interference with the box removing member 30, and there is no possibility that the first cable 22A will be damaged by the shearing action between the end cross beam 18 and the 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 contacts 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 contact between the first cable 22A and the heel wall portion 16A extends over a predetermined length by the trumpet sheath 38 provided on the heel wall portion 16A. Since this is done, there is no possibility that the first cable 22A will be damaged due to interference with the wall 16A.
[0050]
On the other hand, when a lifting force is applied to the bridge girder 14, a large tensile load is applied to the first cable 22A, and the lifting of the bridge girder 14 is restricted by the reaction force of the wall portion 16A to which the one end 22Aa is fixed. At this time, even if the bridge girder 14 is slightly displaced upward, the trumpet sheath 52 provided on the chest wall portion 16B secures a clearance between the second cable 22B and the chest wall portion 16B. However, there is no risk of damage due to 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 beam 18 of the bridge beam 14, and both ends thereof are provided on the lower surface 18 a of the end cross beam 18 and It is formed so as to open to the outer surface 18d in the bridge axis direction, and a seismic cable 22 is inserted into the cable insertion hole 20, and one end 22a thereof is fixed to the wall 16A of the abutment 16. In addition, since the other end 22b is fixed to the chest wall 16B of the abutment 16, the following operational effects can be obtained.
[0052]
In other words, the external force that causes the bridge girder 14 to be relatively displaced inward in the axial direction of the bridge, which causes a falling bridge, can be resisted by the reaction force of the chest wall portion 16B to which the other end portion 22b of the seismic cable 22 is fixed. Moreover, it is possible to resist the lifting force acting on the bridge girder 14 that causes the lift by the reaction force of the anchor wall portion 16A to which the one end portion 22a of the earthquake-resistant cable 22 is fixed.
[0053]
And, since the anti-falling bridge function and the anti-lifting function can be obtained at the same time simply by inserting the seismic cable 22 into the end cross beam 18 in this way, the anti-falling bridge structure and the anti-lifting structure are provided separately. Compared with the case where it is made, construction can be simplified and the steel material weight can be reduced. And thereby, construction cost can be reduced.
[0054]
In particular, in this embodiment, the seismic cable 22 includes a first cable 22A in which one end 22Aa is fixed to the anchor wall portion 16A and the other end 22Ab is fixed to the bridge shaft direction outer surface 18d of the end cross beam 18; Since one end 22B is connected and fixed to the other end 22Ab of the first cable 22A, and the other end 22Bb is fixed to the outer surface 16Ba in the bridge axis direction of the chest wall 16B, the second cable 22B is formed. The construction of the second cable 22B can be performed after the construction of the first cable 22A is completed. Therefore, handling of the earthquake-resistant cable 22 becomes easy, and thereby 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 so as to spread on both sides in the bridge axis direction toward the lower surface 18a of the end cross beam 18 by the box removing member 30. Even when the bridge girder 14 is relatively displaced in the direction of the bridge axis, the earthquake-resistant cable 22 is damaged by the shearing action between the end cross-girder 18 and the anchor wall 16A or the interference action between the earthquake-resistant cable 22 and the end cross-girder 18. The risk of being lost can be eliminated.
[0056]
Moreover, in this embodiment, since the intermediate part of the cable penetration hole 20 is comprised by the metal pipe 24 embed | buried in the end cross beam 18, the load which acts on the wall surface of the cable penetration hole 20 from the earthquake-resistant cable 22 is comprised. The majority can be received by the metal tube 24, thereby increasing the insertion support strength for the seismic cable 22. Moreover, by configuring in this way, it is possible to perform the concrete placement of the end cross beam 18 with the earthquake-resistant cable 22 inserted in the cable insertion hole 20 in advance, thereby further improving the workability. Can do.
[0057]
Since the metal pipe 24 is formed by joining the half pipes 24A and 24B divided into two in the direction perpendicular to the bridge axis, both end portions 22Aa and 22Ab of the first cable 22A have a larger diameter than the general portion therebetween. The first cable 22 </ b> A can be inserted into the metal tube 24 by joining the general portion with the half tubes 24 </ b> A and 24 </ b> B sandwiched from both sides.
[0058]
Since the elastic ring 28 is attached to the inner peripheral surface of the lower end opening 24a of the metal tube 24, the seismic cable 22 is connected to the metal tube 24 even when the bridge girder 14 is relatively displaced in the bridge axis direction. It can be prevented in advance that the contact with the lower end opening 24a is likely to cause damage.
[0059]
In the present embodiment, the seismic 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, but this is constituted by a single cable. Of course, you may do it.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view orthogonal to a bridge axis showing a falling bridge and a floating prevention structure in a cable-stayed bridge according to an embodiment of the present invention. FIG. 2 is a detailed sectional view taken along line II-II in FIG. Fig. 4 is a view similar to Fig. 2 showing the lifting prevention structure when the construction of the first cable has been completed and the construction of the second cable has not yet been performed. The same figure as Fig. 2 showing the relative displacement inward in the axial direction.
DESCRIPTION OF SYMBOLS 10 Cable-stayed bridge 12 Seismic isolation bearing 14 Bridge girder 16 Abutment 16A Anchor wall part 16B Chest wall part 16a Upper surface 16b Position shift prevention protrusion 16c Bridge axial direction outer surface 18 End cross beam 18a Lower surface 18b Position shift prevention protrusion 18c Manhole 18d Bridge Axial outer surface 20 Cable insertion hole 22 Earthquake-resistant cable 22A First cable 22B Second cables 22a, 22Aa, 22Aa One end 22b, 22Ab, 22Bb Other end 24 Metal tube 24A, 24B Half-split tube 24a Lower end opening 26 Bolt 28 Elasticity Ring 30 Unboxing member 32, 40 Anchor plate with steel pipe 34 Reinforcement spiral rebar 36, 46, 56 Reinforcement rebar 38, 52 Trumpet sheath 42, 48, 62 Nut 44, 68 Steel cap 50 Expandable sheath 54 Guide pipe 58 Connector 60 Spring 64 Buffer 66 Stopper Over door

Claims (6)

A structure for preventing the bridge girder from falling off the abutment and floating at the end fulcrum of the cable stayed bridge,
A cable insertion hole whose middle part is curved in a substantially arc shape is formed in the end cross girder of the bridge girder so that both ends of the cable insertion hole are opened to the lower surface of the end cross girder and the outer surface in the bridge axial direction. And
A predetermined seismic cable is inserted into this cable insertion hole,
One end of the seismic cable is anchored to the abutment wall of the abutment, and the other end of the seismic cable is anchored to the chest wall of the abutment. Prevention structure. The seismic cable includes a first cable having one end fixed to the anchor wall and the other end fixed to the outer surface of the end cross beam in the bridge axis direction, and one end to the other end of the first cable. 2. The structure for preventing falling and floating in a cable-stayed bridge according to claim 1, comprising: a second cable having a second end fixed to the outer surface of the chest wall in the bridge axial direction. 3. The oblique line according to claim 1, wherein a portion of the cable insertion hole near the lower surface of the end cross beam is formed so as to spread on both sides in the bridge axis direction toward the lower surface of the end cross beam. Falling bridge and lifting prevention structure in Zhang Bridge. The falling bridge and the floating prevention structure in the cable-stayed bridge according to any one of claims 1 to 3, wherein an intermediate portion of the cable insertion hole is formed of a metal pipe embedded in the end cross beam. 5. The structure for preventing falling and lifting in a cable-stayed bridge according to claim 4, wherein the metal pipe is formed by joining two half-split pipes divided in a direction perpendicular to the bridge axis. 6. The falling bridge and floating prevention structure for a cable-stayed bridge according to claim 4, wherein an elastic ring is attached to an inner peripheral surface of a lower end opening of the metal pipe.

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