JP2007126909A - Demolition and removal method of arch bridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform work of demolishing an arch bridge and removing it from the constructed location in a short time at a low cost. <P>SOLUTION: After breaking up part of a stiffening girder and vertical members, an arch rib 16 is cut at a part near its one end, and a support tool 108 rotatable around a vertical axis Ax is installed near an arch abutment 14L located at the one end, to support the arch rib 16 by the support tool 108. An outer cable 114 is then arranged above the arch rib 16, and its tip part is anchored to a part near the other end of the arch rib 16, while its base end is anchored to an anchor tool 102 installed in a predetermined position on the one end side. After tensing the outer cable 114, the arch rib 16 is cut on the other end side rather than the tip anchored position of the outer cable 114. The arch rib 16 is then turned around the vertical axis Ax into the vicinity of the inclined ground 4L on the one end side. Installation of timbering is thereby dispensed with. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for dismantling and removing an arch bridge in which the arch bridge is dismantled and removed from the installation position.

  The dismantling / removal work of the arch bridge is performed with the aging of the arch bridge, or when the arch bridge is constructed as an overpass, it is performed with the widening work of the main road.

  In this dismantling and removal work, a method is generally employed in which a support work is installed and the arch bridge is cut at a plurality of locations, and then these are removed from the installation position using a large crane or the like.

  In “Patent Document 1”, the stiffening girder and the vertical member of the arch bridge are dismantled and removed, and then a gate-type steel tower is installed on the arch abut located at both ends of the arch rib, and the arch rib is slanted from both sides. A method is also described in which a part of the arch rib is temporarily suspended by a truck crane, the arch rib is cut, and the temporarily suspended part is removed from the installation position by the truck crane.

JP 2005-83186 A

  When dismantling the arch rib, the arch rib is structurally very unstable, unlike when the arch rib is in a completed state. For this reason, the same construction material as the time of construction of an arch rib is needed, and there exists a problem that the cost of demolition removal more than the construction cost of a new bridge will be needed depending on the demolition removal conditions of an arch bridge.

  In the conventional general dismantling and removal method described above, when the arch bridge is a mountain bridge, the installation cost of the support work is increased and a large crane is required, and the arch bridge is an overpass bridge. In this case, there is a problem that the main road is closed for a long time and a special removal work vehicle is required.

  The dismantling / removal method described in the above-mentioned “Patent Document 1” is the dismantling / removal of the arch ribs in the reverse procedure to the construction of the arch ribs by the slanting hanging construction method. There is a problem that the removal cost becomes necessary.

  The present invention has been made in view of such circumstances, and provides a method for dismantling and removing an arch bridge that can disassemble the arch bridge and remove it from the installation position in a short time and at a low cost. It is intended to do.

  According to the present invention, the arch rib is swung around a predetermined vertical axis so that the arch rib is removed from the installation position, and the above object is achieved by applying a predetermined device to realize this. Is.

That is, the method for dismantling and removing the arch bridge according to the present invention is as follows.
In the dismantling and removal method of the arch bridge that dismantles the arch bridge and removes it from the installation position,
After dismantling at least part of the stiffening girders and vertical members of the arch bridge,
The arch bridge of the arch bridge is cut at a portion near one end of the arch rib, and a support jig that is rotatable around a vertical axis is installed near the arch abut located at the one end. To support the arch rib,
Next, an outer cable is disposed above the arch rib, and the distal end portion of the outer cable is fixed to the vicinity of the other end portion of the arch rib, and the base end portion of the outer cable is set at a predetermined position on the one end side. After fixing the fixing cable installed in the fixing cable and tensioning the outer cable, the arch rib is cut on the other end side from the fixing position of the front end portion of the outer cable,
Thereafter, the arch rib is turned around the vertical axis to the vicinity of the ground on the one end portion side.

  The dismantling of the above-mentioned “stiffening girders and vertical members” may be performed on all of them, or may be performed only on a part thereof. In the latter case, the specific part to be disassembled is not particularly limited as long as it does not interfere with the turning of the arch rib.

  The “fixing jig” is installed at a predetermined position on one end side of the arch rib, but the specific configuration is particularly limited as long as it can fix the base end portion of the outer cable. Further, the specific position of the “predetermined position” is not particularly limited.

  The “turning” around the vertical axis of the arch rib is not particularly limited as long as the turning is performed to the vicinity of the ground on one end side of the arch rib.

  As shown in the above configuration, the method of dismantling and removing the arch bridge according to the present invention includes disassembling at least a part of the stiffening girder of the arch bridge and the vertical member, and then cutting the arch rib at a portion near one end thereof. A support jig that can rotate around the vertical axis is installed near the arch abutment located at one end, and the arch rib is supported by this support jig. Next, an external cable is placed above the arch rib. The distal end portion is fixed to the vicinity of the other end portion of the arch rib, the proximal end portion is fixed to a fixing jig installed at a predetermined position on the one end portion side, and the outer cable is tensioned. Thereafter, the arch rib is cut at the other end side from the fixing position of the front end portion of the outer cable, and then the arch rib is swung around the vertical axis to the ground near the one end side. Since it way, it is possible to obtain the following effects.

  That is, since the arch rib is turned around the vertical axis to be removed from the installation position, it is possible to eliminate the need for a support work. As a result, the cost of dismantling and removing the arch bridge can be greatly reduced and the time required for dismantling and removal can be greatly shortened as compared with the conventional dismantling and removing method.

  Moreover, since the arch function is maintained even after the arch rib is cut due to the tensioned arrangement of the outer cable, it can be maintained in a structurally stable state during the turning of the arch rib. Thereby, the safety of the dismantling and removal work can be ensured.

  As described above, according to the present invention, the work of dismantling the arch bridge and removing it from the installation position can be performed in a short period of time and at a low cost while ensuring safety.

  Moreover, in the present invention, it is possible to remove the arch bridge from this erection position while minimizing the dismantling work at the erection position, so the demolition and removal work is hardly affected by the conditions directly under the arch bridge. It can be performed. As a result, when the arch bridge is an overpass, it is possible to significantly reduce the period of closing the main road compared to the conventional art.

  In the above configuration, among the stiffening girder and the vertical member of the arch bridge, the vertical member arranged on the arch abut on the one end side and the abutment on the one end side from the vicinity of the upper end of the vertical member in the stiffening girder If the fixing jig is installed in the vicinity of the upper end surface of the vertical member on the upper surface of the stiffening girder, the above-mentioned fixing jig is installed. The need to build a new structure can be eliminated. As a result, the cost for dismantling and removing the arch bridge can be further reduced, and the time required for dismantling and removal can be further shortened. Moreover, in this case, the fixing jig can be installed in the vicinity of the vertical axis that is the turning center of the arch rib, so that the outer cable is maintained in the desired tensioned state during the turning of the arch rib. Is easily possible.

  In the above configuration, among the vertical members of the arch bridge, the lower end portion of the vertical member arranged in the vicinity of the other end portion of the arch rib is left without being dismantled, and the distal end portion of the outer cable is attached to the lower end portion of the vertical member. By fixing, the tip of the outer cable can be fixed reliably and easily, and the cost of dismantling and removal due to the newly installed fixing portion can be suppressed.

  In the above configuration, among the vertical members of the arch bridge, leave the vertical member disposed between one end of the arch rib and the center thereof without dismantling, and install a pyrone on the upper end of the vertical member. If the outer cable is locked to the upper end of the pyrone, the tension of the outer cable can be arranged with the outer cable deflected so that the arch function of the arch rib can be more reliably maintained. it can.

  In the above configuration, if the fixing jig is formed with a groove or hole for inserting an outer cable that expands in a trumpet shape in a horizontal plane, a local overload is applied to the outer cable when the arch rib is swung. The risk of spending is eliminated.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a side view showing an arch bridge 10 to which the method for dismantling and removing an arch bridge according to an embodiment of the present invention is viewed from the direction orthogonal to the bridge axis.

  As shown in the figure, the arch bridge 10 is an upper concrete arch bridge having a bridge length of about 80 to 90 m and an arch span length of about 50 to 60 m, and straddles the main road 2. It is built as a bridge.

  That is, this arch bridge 10 is between a pair of arch abutments 14L, 14R installed on the upper end surfaces of a pair of deep foundations 12L, 12R embedded in inclined grounds 4L, 4R on both sides of the main road 2. While the arch ribs 16 are installed, six vertical members 18L1, 18L2, 18L3, 18R1, 18R2, 18R3 are arranged at predetermined intervals in the bridge axis direction on the upper surfaces of the arch abutments 14L, 14R and the arch ribs 16, respectively. The six vertical members 18L1, 18L2, 18L3, 18R1, 18R2, and 18R3 have a configuration in which a stiffening girder 20 constituting an upper floor slab is disposed on the upper end surface. The both ends of the stiffening girder 20 in the direction of the bridge axis are supported by a pair of abutments 22L and 22R installed on the upper sides of the inclined grounds 4L and 4R on both sides of the main road 2.

  At this time, in the arch bridge 10, the stiffening girder 20 extends so as to incline slightly downward from the left abutment 22L toward the right abutment 22R in FIG. 14L and 14R are arranged such that the right arch abutment 14R is located slightly below the left arch abutment 14L.

  Of the six vertical members 18L1, 18L2, 18L3, 18R1, 18R2, and 18R3, the vertical member 18L1 is disposed on the arch abutment 14L on one end side (left end portion side in the figure) of the arch rib 16, and the vertical member 18L2 is disposed in the vicinity of one end of the arch rib 16, and the vertical member 18L3 is disposed closer to the center of the arch rib 16 than the vertical member 18L2, while the vertical member 18R1 is disposed in addition to the arch rib 16. Arranged on the arch abutment 14R on the end side (right end side in the figure), the vertical member 18R2 is disposed in the vicinity of the other end of the arch rib 16, and the vertical member 18R3 is disposed on the vertical member 18R2. It is arrange | positioned rather than the center part of the arch rib 16 rather than.

  Next, a method for dismantling the arch bridge 10 and removing it from the installation position will be described.

  FIGS. 2-6 is a side view which shows the process (STEP1-5) of this dismantling removal method, and FIG. 7 is a top view which shows the last process (STEP6).

  First, as shown in FIG. 2, among the stiffening girder 20 of the arch bridge 10 and the six vertical members 18L1, 18L2, 18L3, 18R1, 18R2, and 18R3, a portion indicated by a broken line in the figure is disassembled.

  That is, for the three vertical members 18L1, 18L2, and 18L3 located on the left side, the vertical member 18L2 between them is disassembled while leaving the vertical member 18L1 and the vertical member 18L3 near the center of the arch rib 16 left. On the other hand, for the three vertical members 18R1, 18R2, and 18R3 positioned on the right side, the vertical member 18R1 and the vertical member 18R3 near the center of the arch rib 16 are disassembled and other than the lower end 18R2a of the vertical member 18R2 positioned therebetween. The part of is dismantled.

  Moreover, about the left side part of the arch rib 16 in the stiffening girder 20, the part from the center part vicinity to the slightly right side of the vertical material 18L1 on the arch abutment 14L is dismantled. On the other hand, as for the right part of the arch rib 16 in the stiffening girder 20, the part from the vicinity of the center to the right end is dismantled. Thereby, in the stiffening girder 20, the portion integrated with the central portion of the arch rib 16 is left as the central remaining portion 20a, and the portion from the right side to the left end portion of the vertical member 18L1 on the arch abutment 14L is left-side remaining portion. Leave as 20b.

  Next, as shown in FIG. 3, the fixing jig 102 is installed in the vicinity of the upper end surface of the vertical member 18L1 on the upper surface of the left-side remaining portion 20b of the stiffening girder 20, and the upper end portion of the vertical member 18L3 and the stiffening member are fixed. Pilons 104 and 106 are respectively installed on the right end of the upper surface of the central remaining portion 20a of the girder 20. At that time, the pyrone 104 installed at the upper end of the vertical member 18L3 is taller than the pyrone 106 installed at the upper right end of the central remaining portion 20a of the stiffening girder 20.

  Next, as shown in FIG. 4, the arch rib 16 is cut in the vicinity of one end portion thereof, and in the vicinity of the arch abutment 14 </ b> L located at one end portion of the arch rib 16, the support treatment is rotatable around the vertical axis Ax. The tool 108 is installed so that the arch rib 16 is supported by the support jig 108. The support jig 108 is disposed between the ground side block 110 installed on the inclined ground 4L so as to be adjacent to the right side of the arch abut 14L and the rib side block 112 fixed to the cut surface of the arch rib 16. .

  Next, as shown in FIG. 5, the outer cable 114 is disposed above the arch rib 16, and the distal end portion of the outer cable 114 is fixed to the lower end portion 18R2a of the vertical member 18R2, and the proximal end of the outer cable 114 is fixed. The portion is fixed to the fixing jig 102. Further, a plurality of ground anchors 116 are driven into the back surface portion of the abutment 22L in the inclined ground 4L, and these ground anchors 116 are passed through the fixing jig 102, the left side remaining portion 20b of the stiffening girder 20 and the abutment 22L. The tension of the outer cable 114 is resisted.

  Next, as shown in FIG. 6, after tensioning the outer cable 114, the arch rib 16 is cut on the other end side of the vertical member 18R2. At this time, this cutting position is set at a position close to the other end portion of the arch rib 16 so that the remaining cutting portion 16a on the other end side of the arch rib 16 can be easily disassembled.

  Finally, as shown in FIG. 7, the arch rib 16 is turned about 90 ° around the vertical axis Ax to the vicinity of the inclined ground 4L.

  This turning is performed by locking the tip of the wire 118 to the cutting edge on the other end side of the arch rib 16 and winding the wire 118 from the inclined ground 4L side. This winding is performed by driving a winch (not shown) installed at a certain distance from the arch bridge 10 in the direction orthogonal to the bridge axis on the inclined ground 4L.

  When the arch rib 16 is turned in this manner, the vertical member 18L1 is eliminated from the possibility that the vertical member 18L1 falls due to the moment load acting on the fixing jig 102 from the arch rib 16 via the outer cable 114. The stay 120 is installed in advance on the side surface on the turning side.

  The turning of the arch rib 16 is performed with the main road 2 temporarily closed (for example, at night).

  Thereafter, in the inclined ground 4L, the arch rib 16 swung to the vicinity of the inclined ground 4L is disassembled, and the left side portion 20b of the vertical member 18L1 and the stiffening girder 20 is disassembled, and the arch rib 16 is cut in the inclined ground 4R. The remaining part 16a is disassembled.

  8 is a detailed view of a portion VIII of FIG. 6, FIG. 9 is a detailed view of a portion IX of FIG. 6, and FIG. 10 is a detailed view of a portion X of FIG.

  As shown in FIGS. 8 and 10, the fixing jig 102 is installed on the upper surface of the left-side remaining portion 20 b of the stiffening girder 20 by connecting the fixing jig 102 to a plurality of PC steel bars 124 via wedge-shaped spacers 122. By tightening and fixing to the left remaining portion 20b.

  The fixing jig 102 is formed with an outer cable insertion hole 102a that expands in a trumpet shape in a horizontal plane. Then, the fixing jig 102 is installed so that the end surface of the outer cable insertion hole 102a on the large-diameter opening side is directed to the approximate center of the turning angle range of the arch rib 16.

  Further, a jack 126 is attached to the end surface of the fixing cable 102 on the small diameter opening side of the outer cable insertion hole 102a, and the tension force of the outer cable 114 is introduced using the jack 126. A deflection pipe 128 for inserting the outer cable 114 is attached to the upper end of the pyrone 104 installed at the upper end of the vertical member 18L3. A deflection tube similar to the deflection tube 128 is also attached to the upper end of the pyrone 106.

  As shown in FIG. 8, the support jig 108 having a pin support structure is used, and its lower structure part is fixed to the ground side block 110 with a plurality of anchor bolts 130, and the upper structure part is provided with a plurality of structure parts. It is fixed to the rib side block 112 with the embedded bolt 132.

  As shown in FIG. 9, the fixing of the distal end portion of the outer cable 114 to the lower end portion 18R2a of the vertical member 18R2 forms a wedge-shaped notch portion 18R2a1 on the right side surface of the lower end portion 18R2a, and this notch portion 18R2a1. An outer cable insertion hole 18R2a2 that is open to the arch rib 16 is formed substantially in parallel with the arch axis of the arch rib 16, and the outer cable 114 is inserted into the outer cable insertion hole 18R2a2 using the fixing tool 134. .

  As described above in detail, the method for dismantling and removing the arch bridge according to the present embodiment disassembles part of the stiffening girder 20 of the arch bridge 10 and the vertical members 18L1, 18L2, 18L3, 18R1, 18R2, and 18R3. Thereafter, the arch rib 16 is cut at a portion in the vicinity of one end thereof, and a support jig 108 that is rotatable around the vertical axis Ax is installed in the vicinity of the arch abutment 14L located at the one end. Then, the arch rib 16 is supported by the outer cable 114. Next, the outer cable 114 is disposed above the arch rib 16, the distal end thereof is fixed to the vicinity of the other end of the arch rib 16, and the proximal end thereof is fixed to the one end. After fixing to the fixing jig 102 installed at a predetermined position on the side and tensioning the outer cable 114, the arch rib 16 is attached to the outer cable 11. Since the arch rib 16 is turned to the vicinity of the inclined ground 4L on the one end side around the vertical axis Ax, the cutting is performed on the other end side with respect to the fixing position of the tip end portion of the head. Advantageous effects can be obtained.

  That is, since the arch rib 16 is turned around the vertical axis Ax to be removed from the installation position, it is not necessary to install a support work. As a result, the cost of dismantling / removing the arch bridge 10 can be greatly reduced and the time required for dismantling / removing can be greatly shortened as compared with the conventional dismantling / removing method.

  Moreover, since the arch function is maintained even after the arch rib 16 is cut due to the tensioned arrangement of the outer cable 114, the arch rib 16 can be maintained in a structurally stable state during the turning. Thereby, the safety of the dismantling and removal work can be ensured.

  As described above, according to the present embodiment, the work of dismantling the arch bridge 10 and removing it from the installation position can be performed in a short period and at a low cost while ensuring safety.

  Moreover, in the present embodiment, the dismantling work at the erection position can be minimized and the arch bridge 10 can be removed from the erection position, so that it is hardly affected by the conditions immediately below the arch bridge 10. Dismantling and removal work can be performed. And thereby, when the arch bridge 10 is an overpass like this embodiment, the road stop period of the main road 2 can be shortened significantly compared with the past.

  In the present embodiment, among the stiffening girder 20 of the arch bridge 10 and the vertical members 18L1, 18L2, 18L3, 18R1, 18R2, and 18R3, the vertical member 18L1 and the auxiliary member arranged on the arch abutment 14L on the one end side. The portion from the vicinity of the upper end of the vertical member 18L1 in the rigid girder 20 to the abutment 22L on the one end side is left without being disassembled, and the top of the vertical member 18L1 on the upper surface of the left-side remaining portion 20b of the stiffening girder 20 is left. Since the fixing jig 102 is installed in the vicinity of the end face, it is possible to eliminate the need to construct a new structure for the installation of the fixing jig 102. As a result, the cost of dismantling and removing the arch bridge 10 can be further reduced, and the time required for the dismantling and removing can be further shortened. In addition, by doing so, the fixing jig 102 can be installed in the vicinity of the vertical axis Ax serving as the turning center of the arch rib 16, so that the outer cable 114 is placed in the desired tension arrangement while the arch rib 16 is turning. It can be easily maintained in a state.

  Further, in the present embodiment, the lower end portion 18R2a of the vertical member 18R2 disposed in the vicinity of the other end portion of the arch rib 16 is left without being disassembled, and the distal end portion of the outer cable 114 is fixed to the lower end portion 18R2a. Therefore, the front end portion of the outer cable 114 can be fixed reliably and easily, and the cost of dismantling and removal due to the newly installed fixing portion can be suppressed.

  In the present embodiment, the vertical member 18R3 disposed at a position near the central portion between the one end portion of the arch rib 16 and the central portion thereof is left without being disassembled, and the upper end portion of the vertical member 18R3 is left. Since the pyrone 104 is installed and the outer cable 114 is locked to the upper end portion of the pyrone 104, the tension arrangement of the outer cable 114 can be more reliably achieved to maintain the arch function of the arch rib 16. This can be performed with the outer cable 114 deflected.

  At this time, in the present embodiment, the pyrone 106 is also installed at the upper right end portion of the central remaining portion 20a of the stiffening girder 20, and the pyrone 104 is installed at the upper end portion of the vertical member 18L3. Accordingly, since a tall one is used, the tensioning of the outer cable 114 can be performed in a state more suitable for maintaining the arch function.

  Furthermore, in the present embodiment, the fixing jig 102 is formed with an outer cable insertion hole 102a that expands in a trumpet shape in a horizontal plane, so that when the arch rib 16 is turned, the outer cable 114 is The possibility of applying a local overload can be eliminated.

  By the way, in the said embodiment, although the vertical axis line Ax at the time of turning the arch rib 16 was demonstrated in the vicinity of the arch abutment 14L located in the one end part side, instead of doing in this way, vertical It is also possible to position the axis Ax in the vicinity of the arch abutment 14R located on the other end portion side of the arch rib 16, and even in this case, the same effect as the above embodiment can be obtained.

  Moreover, in the said embodiment, although the case where the arch bridge 10 used as the application object of the demolition removal method was an arch bridge from which the height of the both ends of the arch rib 16 differed, the demolition removal method of the said embodiment was demonstrated. Of course, the arch rib 16 can be applied to an arch bridge having the same height at both ends.

  Furthermore, in the said embodiment, although the case where the arch bridge used as the application object of the demolition removal method was a concrete arch bridge, it applied similarly to steel arch bridges.

The side view which shows the arch bridge used as the application object of the demolition removal method of the arch bridge which concerns on one Embodiment of this invention in the state seen from the bridge-axis orthogonal direction Side view showing the process (STEP 1) of the dismantling and removal method Side view showing the process (STEP 2) of the dismantling and removal method Side view showing the process (STEP 3) of the dismantling and removal method Side view showing the process (STEP 4) of the dismantling and removal method Side view showing the process (STEP 5) of the dismantling and removal method The top view which shows the process (STEP6) of the said dismantling removal method Detailed view of section VIII in FIG. Detailed view of part IX in FIG. Detailed view of part X in FIG.

Explanation of symbols

Two main roads 4L, 4R Inclined ground 10 Arch bridge 12L, 12R Deep foundation 14L, 14R Archabat 16 Arch rib 16a Remaining cut portion 18L1, 18L2, 18L3, 18R1, 18R2, 18R3 Vertical material 18R2a Lower end portion 18R2a1 Notch portion 2 Insertion hole 20 Stiffening girder 20a Center remaining part 20b Left side remaining part 22L, 22R Abutment 102 Fixing jig 102a Outer cable insertion hole 104, 106 Pilon 108 Bearing jig 110 Ground side block 112 Rib side block 114 Outer cable 116 Ground anchor 118 Wire 120 Stay 122 Spacer 124 PC Steel Bar 126 Jack 128 Deflection Pipe 130 Anchor Bolt 132 Embedded Bolt 134 Fixing Tool Ax Vertical Axis

Claims (5)

In the dismantling and removal method of the arch bridge that dismantles the arch bridge and removes it from the installation position,
After dismantling at least part of the stiffening girders and vertical members of the arch bridge,
The arch bridge of the arch bridge is cut at a portion near one end of the arch rib, and a support jig that is rotatable around a vertical axis is installed near the arch abut located at the one end. To support the arch rib,
Next, an outer cable is disposed above the arch rib, and the distal end portion of the outer cable is fixed to the vicinity of the other end portion of the arch rib, and the base end portion of the outer cable is set at a predetermined position on the one end side. After fixing the fixing cable installed in the fixing cable and tensioning the outer cable, the arch rib is cut on the other end side from the fixing position of the front end portion of the outer cable,
Thereafter, the arch rib is turned to the vicinity of the ground on the one end side around the vertical axis, and the arch bridge is dismantled and removed. Of the stiffening girder and the vertical member of the arch bridge, the vertical material disposed on the arch abut on the one end side and the portion of the stiffening girder from the vicinity of the upper end of the vertical material to the abutment on the one end side Leave without dismantling,
2. The method for dismantling and removing an arch bridge according to claim 1, wherein the fixing jig is installed in the vicinity of the upper end surface of the vertical member on the upper surface of the stiffening girder. Of the vertical material of the arch bridge, leave the lower end of the vertical material arranged in the vicinity of the other end of the arch rib without dismantling,
The method for dismantling and removing an arch bridge according to claim 1 or 2, wherein a front end portion of the outer cable is fixed to a lower end portion of the vertical member. Of the vertical material of the arch bridge, leave the vertical material arranged between one end of the arch rib and the central part of the arch rib without dismantling,
4. A method for dismantling and removing an arch bridge according to any one of claims 1 to 3, wherein a pyrone is installed at the upper end of the vertical member, and the outer cable is locked to the upper end of the pyrone.   The method for dismantling and removing the arch bridge according to any one of claims 1 to 4, wherein a groove or a hole for inserting an outer cable extending in a trumpet shape in a horizontal plane is formed in the fixing jig.

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