Suspension structure erection method of suspension bridge and suspension structure erection device

Abstract

Provided are a suspension structure erection method of a suspension bridge capable of reducing the weight of an erection device body, and a suspension structure erection device.　In the present invention, a main cable 3 is connected to the upper end side of a suspension member 40, which is supported by an erection device body 20, while a suspension structure 5, prior to erection, is connected to the lower end side of the suspension member 40, thereby enabling the suspension structure 5 to be lifted to an erection position by the suspension member 40. Therefore, a load of the suspension structure 5, which is a heavy object, is not applied to the erection device body 20, and accordingly, the strength of the erection device body 20 can be reduced. Since the suspension member 40, which is supported by the erection device body 20, is configured to be moved by the support mechanism 50 to a predetermined position in the direction perpendicular to the bridge axis, so as to avoid contact with a hanger cable 4, the suspension member 40 does not come into contact with the hanger cable 4 during the movement in the bridge axis direction, and can pass along the side of the hanger cable 4 without hindrance.

Description

Method and device for erecting a suspended structure for a suspension bridge

[0001] The present invention relates to a method and device for erecting a suspended structure for a suspension bridge, for hoisting and erecting a suspended structure such as a stiffening girder in a suspension bridge to be erected over a river, a strait, or the like.

[0002] Generally, a suspension bridge erected over a river, strait, etc. is composed of a number of main towers spaced apart in the bridge axis direction, a main cable stretched between the main towers, a number of hanger cables spaced apart in the bridge axis direction, and a suspension structure such as a steel beam suspended from the main cable by each hanger cable.

[0003] When erecting such a suspension bridge, a main cable is stretched between the main towers, and then multiple suspension structures divided in the bridge axis direction are transported on water below the main cable using a barge or similar, and the suspension structures are then lifted to their erection position using an erection device installed on the main cable (see, for example, Patent Documents 1 and 2).

[0004] In addition, the erection device has an erection device main body that extends perpendicular to the bridge axis across main cables arranged on both ends perpendicular to the bridge axis, and is configured to lift suspended structures using hanging materials suspended from the erection device main body, and by running on the main cables, moves in the bridge axis direction to lift other suspended structures.

[0005] JP-A No. 50-9938 JP-A No. 60-88705

[0006] In the above-mentioned erection device, when the device moves in the bridge axis direction along the main cable, the hanging material suspended from the device body is positioned at a position offset perpendicular to the bridge axis relative to the main cable so that it does not interfere with the hanger cable, and therefore the hanging load of the suspended structure is transmitted to the main cable via the device body.

[0007] As a result, in the erection device body, the loading point, where the suspended structure is suspended, and the reaction support point located on the main cable are separated in the direction perpendicular to the bridge axis, so a bending moment due to the suspended load of the suspended structure occurs in the erection device body. For this reason, it is necessary to increase the bending strength of the erection device body, but in order to increase the strength, the erection device body must be made larger, which increases the weight of the erection device body accordingly.

[0008] In other words, an increase in the weight of the erection device itself affects the required capacity of the equipment used to set up and move the erection device, such as the tower-top crane used to assemble and dismantle the erection device, and the tower-top winch used to move the erection device along the main cable.In particular, for suspension bridges where the spacing between the main cables is wide, the erection device itself becomes even larger and heavier, which can cause problems such as restrictions on the equipment capacity for the entire suspension bridge erection work.

[0009] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a method and device for erecting a suspended structure for a suspension bridge that can reduce the weight of the main body of the erection device.

[0010] In order to achieve the above-mentioned object, the present invention provides a method for erecting a suspended structure for a suspension bridge, which comprises main cables arranged on both sides of the suspension bridge in the direction perpendicular to the bridge axis, a plurality of hanger cables arranged at intervals in the direction of the bridge axis, and a suspended structure suspended from the main cables by each hanger cable. The method comprises using an erection device body formed to extend across each of the main cables in the direction perpendicular to the bridge axis, and which is installed on the main cables to be movable in the direction of the bridge axis, and connecting the upper ends of the suspension members supported by the erection device body to the main cables, and The suspension structure before installation is connected to the lower end of the member, and the suspension structure is lifted up to the installation position using the suspension member. After connecting the suspension structure to the hanger cable suspended from the main cable, the connection between the lower end of the suspension member and the suspension structure is released, and the connection between the upper end of the suspension member and the main cable is released. The suspension member supported by the main body of the installation device is moved to a predetermined position perpendicular to the bridge axis where contact with the hanger cable can be avoided when moving in the bridge axis direction, and the installation device supporting the suspension member is moved along the main cable to the installation position of the next suspension structure.

[0011] Furthermore, in order to achieve the above-mentioned object, the present invention provides a suspension structure erection device for erecting a suspension bridge suspension structure comprising main cables arranged on both sides of the suspension bridge in the direction perpendicular to the bridge axis, a plurality of hanger cables arranged at intervals in the bridge axis direction, and a suspension structure suspended from the main cables by each hanger cable, the device comprises an erection device main body formed to extend across each of the main cables in the direction perpendicular to the bridge axis and installed on the main cables so as to be movable in the bridge axis direction, a suspension member whose upper end is detachably connected to the main cable and whose lower end can be connected to a suspension structure, and a support mechanism which supports the upper end of the suspension member and which can move the suspension member in the direction perpendicular to the bridge axis when it is released from connection with the main cable to a position where it can avoid contact with the hanger cables when moved in the bridge axis direction.

[0012] As a result, the upper end of the suspension member supported by the erection device main body is connected to the main cable, and the suspended structure before installation is connected to the lower end of the suspension member, so the load of the heavy suspended structure is not applied to the erection device main body, and the strength of the erection device main body can be reduced accordingly. Also, after the hanger cable suspended from the main cable is connected to the suspended structure, the connection between the lower end of the suspension member and the suspended structure is released, and the connection between the upper end of the suspension member and the main cable is released, and the suspension member supported by the erection device main body is moved to a predetermined position perpendicular to the bridge axis where it can avoid contact with the hanger cable. Therefore, when the erection device supporting the suspension member is moved along the main cable to the installation position of the next suspended structure, the suspension member does not come into contact with the hanger cable and passes next to the hanger cable without hindrance.

[0013] Furthermore, in order to achieve the above-mentioned object, the present invention provides a method for erecting a suspension structure for a suspension bridge, which includes main cables arranged on both sides of the suspension bridge in the direction perpendicular to the bridge axis, multiple hanger cables arranged at intervals in the direction of the bridge axis, and a suspension structure suspended from the main cables by each hanger cable, the method comprising the steps of: using an erection device body formed to extend across each of the main cables in the direction perpendicular to the bridge axis; and installing an erection device that is freely movable in the direction of the bridge axis on the main cables; and placing a pair of first suspension members, the upper ends of which are connected to the end sides of the erection device body in the direction perpendicular to the bridge axis, on both sides of the main cables in the direction perpendicular to the bridge axis; The suspended structure before installation is connected to second suspension members that are connected to the lower end of each first suspension member and extend perpendicular to the bridge axis, and the suspension structure is lifted to the installation position using each suspension member. After connecting the hanger cable suspended from the main cable to the suspended structure, the connection between the lower end of the first suspension member on the outside in the perpendicular direction to the bridge axis and the second suspension member is released, and the second suspension member connected to the first suspension member on the inside in the perpendicular direction to the bridge axis is moved inward in the perpendicular direction to the bridge axis to a position where contact with the hanger cable can be avoided when moving in the bridge axis direction, and the installation device with each suspension member connected is moved along the main cable to the installation position of the next suspended structure.

[0014] In order to achieve the above object, the present invention provides a suspension structure erection device for erecting a suspension bridge comprising main cables arranged on both sides of the suspension bridge in the direction perpendicular to the bridge axis, a plurality of hanger cables arranged at intervals in the direction of the bridge axis, and a suspension structure suspended from the main cables by each hanger cable, the device comprising: an erection device main body formed to extend across each of the main cables in the direction perpendicular to the bridge axis and installed on the main cables to be movable in the direction of the bridge axis; The device comprises a pair of first suspension members arranged on both sides, with their upper ends connected to the end sides of the installation device main body in the direction perpendicular to the bridge axis, and second suspension members connected to the lower ends of each first suspension member and formed to extend in the direction perpendicular to the bridge axis, to which the suspension structure is connected before installation.The second suspension member is disconnected from the lower end side of the first suspension member on the outside in the direction perpendicular to the bridge axis, and is connected to the suspension member on the inside in the direction perpendicular to the bridge axis, and is configured to be movable inward in the direction perpendicular to the bridge axis to a position where it can avoid contact with the hanger cable when moving in the bridge axis direction.

[0015] As a result, a pair of first suspension members, whose upper ends are connected to the end sides of the installation device main body in the direction perpendicular to the bridge axis, are positioned on both sides of the main cable in the direction perpendicular to the bridge axis, and the suspension structure before installation is connected to second suspension members that are connected to the lower ends of each first suspension member and extend in the direction perpendicular to the bridge axis.As a result, the load of the heavy suspension structure is not applied to the central side of the installation device main body in the direction perpendicular to the bridge axis, and the strength of the central side of the installation device main body in the direction perpendicular to the bridge axis can be reduced accordingly. Furthermore, after the hanger cable suspended from the main cable is connected to the suspended structure, the connection between the lower end of the first suspension member on the outside in the direction perpendicular to the bridge axis and the second suspension member is released, and the second suspension member connected to the first suspension member on the inside in the direction perpendicular to the bridge axis is moved inward in the direction perpendicular to the bridge axis to a position where it can avoid contact with the hanger cable when moving in the bridge axis direction.Therefore, when the erection device hanging each suspension member is moved along the main cable to the erection position of the next suspended structure, each suspension member does not come into contact with the hanger cable and passes alongside the hanger cable without hindrance.

[0016] According to the present invention, the load of the heavy suspended structure is not applied to the erection device body or the center in the direction perpendicular to the bridge axis. Therefore, unlike conventional methods, the bending moment caused by the suspended load of the suspended structure is not generated on the erection device body, and the strength of the erection device body can be correspondingly reduced. This simplifies the structure of the erection device body and significantly reduces its weight. This reduces the required capacity of equipment used to install and move the erection device, such as the tower-top crane used to assemble and disassemble the erection device body and the tower-top winch used to move the erection device along the main cable, thereby improving workability and reducing costs. In particular, the weight of the erection device body can be reduced even when the main cables are spaced widely apart, making this extremely advantageous for erecting such wide suspension bridges. Furthermore, when the erection device supporting the suspension members is moved along the main cable to the next suspension structure installation position, the suspension members do not come into contact with the hanger cables and can pass alongside the hanger cables without any hindrance. Therefore, the erection device can be easily moved along the main cable without the suspension members interfering with the hanger cables.

[0017] Schematic side view of a suspension bridge showing a first embodiment of the present invention. Schematic front view of a suspension bridge. Front view of essential parts of a suspended structure erection device. Side view of a suspended structure erection device. Side view of a suspended structure erection device showing the suspended structure erection process. Side view of a suspended structure erection device showing the suspended structure erection process. Front view of essential parts of a suspended structure erection device showing the suspended structure erection process. Side view of a suspended structure erection device showing the suspended structure erection process. Front view of essential parts of a suspended structure erection device showing the suspended structure erection process. Plan view of the second suspension member Plan view of the second suspension member showing the movable part extended Side view of the suspended structure erection device showing the suspended structure erection process Side view of the suspended structure erection device showing the suspended structure erection process Front view of the main part of the suspended structure erection device showing the suspended structure erection process Side view of the suspended structure erection device showing the suspended structure erection process Front view of the main part of the suspended structure erection device showing the suspended structure erection process Front view of the main part of the suspended structure erection device showing the suspended structure erection process Side view of the suspended structure erection device showing the suspended structure erection process

[0018] 1 to 9 show a first embodiment of the present invention, which shows a method and apparatus for erecting a suspended structure of a suspension bridge by hoisting the structure.

[0019] The suspension bridge 1 shown in the figure is equipped with a main cable 3 stretched across main towers 2, and is configured to suspend a suspended structure 5 consisting of a steel girder or the like by a plurality of hanger cables 4 connected to the main cable 3. In this embodiment, one main cable 3 is provided on each end in the direction perpendicular to the bridge axis, and two hanger cables 4 are used at each suspension position.

[0020] Each main cable 3 is arranged at one end and the other end perpendicular to the bridge axis, and a plurality of annular hanging fittings 6 are attached to each main cable 3 to hang each hanger cable 4. The hanging fittings 6 are also provided with connecting parts 6a to which the upper ends of the hanger cables 4 are connected.

[0021] Each hanger cable 4 is provided with connecting portions 4 a and 4 b at the upper and lower ends, respectively, and the connecting portion 4 b on the lower end side is adapted to be connected to the suspended structure 5 side.

[0022] The suspended structure 5 has a first connecting part 5a to which the lower end of the hanger cable 4 is connected, and a second connecting part 5b to which the suspended structure erection device 10 described later is connected, and two first connecting parts 5a are provided at one hanging position of the hanger cable 4, and a second connecting part 5b is provided between each of the first connecting parts 5a.

[0023] The erection device 10 used in the suspended structure erection method of this embodiment comprises an erection device main body 20 formed to extend in a direction perpendicular to the bridge axis, a pair of running units 30 that support the erection device main body 20 and are capable of running on the main cable 3, a hanging member 40 that is detachably connected at its upper end to the main cable 3 and to which a suspended structure 5 can be connected at its lower end, and a support mechanism 50 that supports the upper end of the hanging member 40 and is capable of moving the hanging member 40 in a direction perpendicular to the bridge axis to a position where it can avoid contact with the hanger cable 4 when moved in the bridge axis direction after being released from connection to the main cable 3, and is configured to be installed across each main cable 3 on both sides in the direction perpendicular to the bridge axis as shown in Figure 2.

[0024] The erection device main body 20 is made of beam-like members with a truss structure, and is formed so that the width and height dimensions at both longitudinal ends are smaller than those at the longitudinal center, and is rotatably supported by each traveling unit 30. Furthermore, at both longitudinal ends of the erection device main body 20, connecting parts 21 to which the support mechanisms 50 are connected are provided, and each connecting part 21 is formed to extend downward from the erection device main body 20.

[0025] The traveling unit 30 includes a unit body 31 disposed on the main cable 3, and wheels 32 that engage with the main cable 3 are provided on the underside of the unit body 31 at multiple locations in the longitudinal direction of the unit body 31. In addition, a support member 33 that supports the installation device body 20 is provided on the upper surface of the unit body 31. The support member 33 is composed of a beam portion 33a extending in the longitudinal direction of the unit body 31 and a pair of legs 33b extending diagonally downward from both ends of the beam portion 33a in the longitudinal direction, and by connecting the lower surface of the beam portion 33a to the upper surface of the installation device body 20 via a pivot support portion 33c, the installation device body 20 is supported so that it is always horizontal due to its own weight.

[0026] The suspension member 40 comprises a suspension fitting 41 attached to the main cable 3, a strand jack 42 detachably suspended from the suspension fitting 41, and a strand 43 that lifts the suspended structure 5 with the strand jack 42.

[0027] The hanging bracket 41 is an annular member attached to the outer circumferential surface of the main cable 3 and has a connecting portion 41 a extending downward from the main cable 3 .

[0028] The strand jack 42 is a well-known jack device used for lifting and lowering heavy loads, and has a well-known configuration in which one of a pair of upper and lower clamp mechanisms (not shown) capable of gripping the strand 43 is moved up and down by a hydraulic device, thereby repeatedly gripping and releasing the strand 43 and continuously paying out and repaying the strand 43. In addition, a connecting part 42a is provided at the upper end of the strand jack 42 for detachably connecting to the connecting part 41a of the lifting fitting 41.

[0029] The strand 43 is made up of a plurality of PC steel wires, and its lower end is provided with a connecting portion 43a that is connected to the suspended structure 5. The upper end of the strand 43 is adapted to be wound around a winding portion 44 consisting of a well-known strand winding device, and the winding portion 44 is arranged on the upper surface of the unit body 31 so as to be located above the main cable 3. In this case, the upper end of the strand 43 is arranged along a support member 51 of a support mechanism 50 (described later), and is wound around the winding portion 44 via the upper surface of the installation device body 20.

[0030] The support mechanism 50 has a support member 51 whose one end is rotatably connected to the erection device main body 20, and a hydraulic jack 52 as a driving means for rotating the support member 51, and the other end of the support member 51 is rotatably connected to the upper end side of the hanging member 40.

[0031] The support member 51 is bent in an L-shape, and one end thereof is connected to the underside of the installation device main body 20 via a pivoting support part 51a. In this case, the pivoting support part 51a is disposed between the connecting part 21 of the installation device main body 20 and the main cable 3. The other end of the support member 51 is formed to extend toward the main cable 3, and its tip is connected to the connecting part 42a on the upper end side of the strand jack 42.

[0032] The hydraulic jack 52 is a well-known clevis jack, with one end rotatably connected to the lower end of the connecting portion 21 of the erection device main body 20 and the other end rotatably connected to the L-shaped bent portion of the support member 51. The hydraulic jack 52 extends and contracts in the longitudinal direction, thereby rotating the support member 51 around the rotation support portion 51a on one end side of the support member 51 as a fulcrum.

[0033] Next, the method for erecting a suspended structure according to this embodiment will be described with reference to Figures 5 to 9. The figures show the process of erecting one of the stiffening girders divided into multiple parts in the bridge axis direction as the suspended structure 5.

[0034] First, as shown in Figure 5, two erection devices 10 are placed on the main cable 3 at a distance from each other in the bridge axis direction, and the traveling units 30 are connected to each other by wires 11. In this case, one of the erection devices 10 is connected to a tower top winch (not shown) via a wire 12, and the tower top winch moves each erection device 10 along the main cable 3. In addition, hanger cables 4 are suspended from each of the hoisting fittings 6 of the main cable 3.

[0035] Here, the suspended structure 5 is transported below the installation position by a work vessel such as a barge (not shown), and the suspension members 40 of each erection device 10 are connected to the suspended structure 5 at two locations in the bridge axis direction and two locations perpendicular to the bridge axis. At this time, the connecting portion 42a of the strand jack 42 of each suspension member 40 is connected to the connecting portion 41a on the main cable 3 side, and the connecting portion 43a of the strand 43 is connected to the second connecting portion 5b of the suspended structure 5.

[0036] Next, the strand 43 is pulled up by the strand jacks 42 of each suspension member 40, thereby lifting the suspended structure 5 to the height of the installation position. At that time, to avoid contact with the existing suspended structure 5, the suspended structure 5 is lifted by being displaced a distance S in the bridge axis direction relative to the end face of the existing suspended structure 5. Meanwhile, the load of the suspended structure 5 is applied to the main cable 3 via the lifting fittings 41 to which the upper ends of the strand jacks 42 are connected, so the load of the suspended structure 5 is not applied to the installation device main body 20. Furthermore, when lifting the suspended structure 5, the upper end side of the strand 43 unwound from the strand jack 42 is wound up by the winding section 44.

[0037] Next, the lower end of each hanger cable 4 is connected to each first connecting portion 5a of the suspended structure 5, and then the connection between the lower end of the strand 43 of the suspension member 40 and the second connecting portion 5b of the suspended structure 5 is released as shown in Figure 6. This causes the suspended structure 5 to be supported by each hanger cable 4.

[0038] Next, as shown in Figure 7, the connection between the connecting portion 42a of the strand jack 42 of the suspension member 40 and the connecting portion 41a of the suspension fitting 41 is released. This work is performed by a worker on a scaffold (not shown) located below the main cable 3. Next, the strand jack 42 of the suspension member 40 is moved to a predetermined position perpendicular to the bridge axis by the support mechanism 50. That is, by rotating the support member 51 by the hydraulic jack 52 of the support mechanism 50, the strand jack 42 supported on the other end of the support member 51 is moved to a position where it can avoid contact with the hanger cable 4 when moving in the bridge axis direction, as described below.

[0039] Thereafter, as shown in Fig. 8, each erection device 10 is pulled by the wire 12 to move it to the next erection position along the main cable 3. At that time, the strand jacks 42 of the suspending members 40 have been moved by the support mechanisms 50 to positions where they can avoid contact with the hanger cables 4, so that the suspending members 40 supported by the support mechanisms 50 pass beside the hanger cables 4, as shown in Fig. 9.

[0040] As described above, according to this embodiment, the upper ends of the suspension members 40 supported by the installation device main body 20 are connected to the main cables 3, and the pre-installation suspended structure 5 is connected to the lower ends of the suspension members 40, and the suspended structure 5 is lifted up to the installation position by the suspension members 40, so that the load of the suspended structure 5, which is a heavy object, is not applied to the installation device main body 20, and the strength of the installation device main body 20 can be reduced accordingly. In other words, since the installation device main body 20 only needs to have strength against the loads of the strand jacks 42 and strands 43 of the suspension members 40, no bending moment due to the suspension load of the suspended structure is generated in the installation device main body as in the conventional case, and the structure of the installation device main body 20 can be simplified and significantly lighter. This reduces the required capacity of the equipment used to install and move the erection device 10, such as the tower-top crane used to assemble and dismantle the erection device main body 20 and the tower-top winch used to move the erection device 10 along the main cables 3, thereby improving workability and reducing costs. In particular, even when the spacing between the main cables 3 is wide, the weight of the erection device main body 20 can be kept down, making it extremely advantageous for erecting such wide suspension bridges.

[0041] Furthermore, after connecting the hanger cables 4 suspended from the main cables 3 to the suspended structure 5, the connection between the lower ends of the hanging members 40 and the suspended structure 5 is released, and the connection between the upper ends of the hanging members 40 and the main cables 3 is released, and the hanging members 40 supported by the erection device main body 20 are moved by the support mechanism 50 to a predetermined position perpendicular to the bridge axis where contact with the hanger cables 4 can be avoided. Therefore, when the erection device 10 supporting the hanging members 40 is moved along the main cables to the erection position of the next suspended structure, the hanging members 40 do not come into contact with the hanger cables 4 and can pass by the sides of the hanger cables 4 without hindrance. As a result, even in an erection method in which the suspended structure 5 is lifted by the hanging members 40 connected to the main cables 3, the erection device 10 can be easily moved along the main cables 3 without the hanging members 40 interfering with the hanger cables 4.

[0042] In this case, the support mechanism 50 is composed of a support member 51 whose one end is rotatably connected to the erection device main body 20, and a hydraulic jack 52 that rotates the support member 51, and the upper end of the suspension member 40 is connected to the other end of the support member 51.Therefore, by rotating the support member 51, the suspension member 40 can be easily moved in a direction perpendicular to the bridge axis, making it easy to relocate the erection device 10.

[0043] Furthermore, the suspension member 40 is constructed of a strand jack 42 that feeds and retracts a strand 43 whose lower end is connected to the suspended structure 5, and the upper end of the strand jack 42 is configured to be detachable from the main cable 3 side, so that the suspended structure 5 can be easily lifted by the strand jack 42 connected to the main cable 3 side.

[0044] In this case, the winding section 44 that winds up the upper end of the strand 43 is positioned above the main cable 3, so the weight of the winding section 44 is not added to the installation device main body 20, which has the advantage that the required strength of the installation device main body 20 is not increased by the winding section 44.

[0045] Furthermore, the erection device 10 is equipped with a running unit 30 that can travel on the main cable 3, and the running unit 30 supports the erection device main body 20 so that it can rotate freely around a horizontal axis extending perpendicular to the bridge axis, so that the erection device main body 20 can be rotatably supported on the running unit 30 so that it is always horizontal due to its own weight, and the support member 51 attached to the erection device main body 20 can always be kept vertical even if the erection device 10 tilts depending on the position of the main cable 3 along the length. This allows the support member 51 to rotate on a vertical plane, so that no horizontal force is applied to the support member 51, and the support member 51 can always rotate smoothly.

[0046] In addition, the above embodiment shows a support mechanism 50 that rotates the support member 51, but the support member may be slid to move the suspension member 40 in a direction perpendicular to the bridge axis.

[0047] 10 to 19 show a second embodiment of the present invention, in which the same components as those in the first embodiment are denoted by the same reference numerals.

[0048] The erection device 60 used in the method for erecting a suspended structure of this embodiment comprises an erection device main body 70 formed to extend in a direction perpendicular to the bridge axis, a pair of traveling units 80 that support the erection device main body 70 and are capable of traveling on the main cable 3, a pair of first suspension members 90 that are arranged on both sides of the main cable 3 in the direction perpendicular to the bridge axis and each have their upper ends connected to the erection device main body 60, second suspension members 100 that are connected to the lower ends of each first suspension member 90 and to which the suspended structure 5 is connected before erection, and connecting members 110 that connect the second suspension members 100 that are arranged on each side of the main cable 3 on both sides of the suspension bridge 1 in the direction perpendicular to the bridge axis, and are configured to be installed across each of the main cables 3 on both sides in the direction perpendicular to the bridge axis, similar to the erection device 10 of the first embodiment shown in Figure 2.

[0049] The erection device main body 70 is composed of end beams 71 respectively positioned above each main cable 3, and central beams 72 of a truss structure extending perpendicular to the bridge axis between the end beams 71, and the end beams 71 are formed so that the center of the longitudinal direction is higher than the opposite ends. Connecting portions 71a to which the upper ends of the first suspension members 90 are connected are provided on both longitudinal ends of the end beams 71, and the center of the longitudinal direction of the end beams 71 is rotatably connected to the traveling unit 80.

[0050] The traveling unit 80 includes a unit body 81 disposed on the main cable 3, and wheels 82 that engage with the main cable 3 are provided on the underside of the unit body 81 at multiple locations in the longitudinal direction of the unit body 81. In addition, a rotation support part 81a to which the end side beam part 71 of the erection device body 70 is rotatably connected is provided on the upper surface of the unit body 81, and the erection device body 70 is supported by the rotation support part 81a so that it is always horizontal due to its own weight.

[0051] Each first suspension member 90 consists of a strand jack 91 that is suspended from the end side beam portion 71 of the erection device main body 70 so that it can rotate freely in a direction perpendicular to the bridge axis, and a strand 92 that lifts the suspended structure 5 using the strand jack 91, and is arranged so that the distances from the main cable 3 are equal to each other.

[0052] The strand jack 91 is a well-known jack device used for lifting and lowering heavy objects, and has a well-known configuration in which one of a pair of upper and lower clamp mechanisms (not shown) capable of gripping the strand 92 is moved up and down by a hydraulic device, thereby repeatedly gripping and releasing the strand 92 and continuously paying out and repaying the strand 92. The upper end of the strand jack 91 is connected to the connecting part 71a of the erection device main body 70 so as to be rotatable perpendicular to the bridge axis.

[0053] The strand 92 is made up of a plurality of PC steel wires, and at its lower end is provided a connecting portion 92a that is connected to the suspended structure 5. The upper end of the strand 92 is adapted to be wound around a winding portion 93 made up of a well-known strand winding device, and the winding portion 93 is arranged on the top surface of the unit body 81 so as to be positioned above the main cable 3.

[0054] The second suspension member 100 is made of a beam-shaped steel material extending in the direction perpendicular to the bridge axis, and is provided with connecting parts 101 on both longitudinal ends to which the lower ends of the strands 92 are connected, and with a connecting part 102 in the longitudinal center to which it is connected to the suspended structure 5. The second suspension member 100 is also provided with a pair of widthwise movable parts 103, one end of which is rotatably connected to one longitudinal end side of the second suspension member 100 (the inner side in the direction perpendicular to the bridge axis of the suspension bridge 1), and is configured so that the center of gravity G of the second suspension member 100 can be moved in the direction perpendicular to the bridge axis by rotating the movable parts 103 and extending them inward in the direction perpendicular to the bridge axis of the suspension bridge 1. In this case, a weight 103a is provided on the other end of each movable part 103, and when each movable part 103 is extended, the center of gravity G of the second suspension member 100 moves below the connection part 101 with the first suspension member 90 on the inside in the direction perpendicular to the bridge axis.

[0055] The connecting member 110 consists of a strand jack 111 connected at one end to one of the second suspension members 100 in the direction perpendicular to the bridge axis, and a strand 112 connected at one end to the other second suspension member 100 in the direction perpendicular to the bridge axis, and the strand jack 111 is used to pull the second suspension members 100 together. In this case, the strand jack 111 is connected to the connecting part 101 on the inside of one of the second suspension members 100 in the direction perpendicular to the bridge axis, and the strand 112 is connected to the connecting part 101 on the inside of the other second suspension member 100 in the direction perpendicular to the bridge axis.

[0056] Next, the method for erecting a suspended structure according to this embodiment will be described with reference to Figures 13 to 19. The figures show the process of erecting one of the stiffening girders divided into multiple parts in the bridge axis direction as the suspended structure 5.

[0057] First, as shown in Figure 13, two erection devices 60 are placed on the main cable 3 at a distance from each other in the bridge axis direction, and the traveling units 80 are connected to each other by wires 61. In this case, one of the erection devices 60 is connected to a tower top winch (not shown) via a wire 62, and the tower top winch moves each erection device 60 along the main cable 3. In addition, hanger cables 4 are suspended from each of the hoisting fittings 6 on the main cable 3.

[0058] Here, the suspended structure 5 is transported below the installation position by a work vessel such as a barge (not shown), and each first suspension member 90 of each erection device 60 is connected to the suspended structure 5 at two locations in the bridge axis direction and two locations perpendicular to the bridge axis. At this time, each first suspension member 90 is connected by connecting portion 92a of the strand 92 to the second connecting portion 5b of the suspended structure 5.

[0059] 13 and 14 , the strands 92 are pulled up by the strand jacks 91 of each first suspension member 90, thereby lifting the suspended structure 5 to the height of the installation position. At this time, to avoid contact with the existing suspended structure 5, the suspended structure 5 is lifted by being displaced a distance S in the bridge axis direction relative to the end face of the existing suspended structure 5. Meanwhile, the load of the suspended structure 5 is applied to the main cable 3 from each first suspension member 90 via the end side beams 71 of the erection device main body 70 and the traveling units 80, and therefore the load of the suspended structure 5 is not applied to the central side beams 72 of the erection device main body 70. In other words, the load of the suspended structure 5 is applied to the end side beams 71 from the connecting parts 71 a with each first suspension member 90, and therefore the bending moment due to the load of the suspended structure 5 occurs only between the connecting parts 71 a of the end side beams 71. Furthermore, when the suspended structure 5 is lifted, the upper end of the strand 92 unwound from the strand jack 91 is wound up by the winding section 93 .

[0060] Next, after connecting the lower end of each hanger cable 4 to each first connecting part 5a of the suspended structure 5, the movable part 103 of the second suspension member 100 is extended inward in the direction perpendicular to the bridge axis as shown in Figure 15, and the connection between the lower end of the first suspension member 90 on the outside in the direction perpendicular to the bridge axis and connecting part 101 of the second suspension member 100 is released, and the connection between connecting part 102 of the second suspension member 100 and the second connecting part 5b of the suspended structure 5 is released. As a result, the suspended structure 5 is suspended by each hanger cable 4 as shown in Figure 16. At this time, the second suspension member 100 is suspended by one of the first suspension members 90 only at the connecting part 101 on the inside perpendicular to the bridge axis, but because the extension of the movable part 103 moves the center of gravity G to the connecting position with one of the first suspension members 90, the second suspension member 100 is kept horizontal without tilting with the connecting part 101 with the first suspension member 90 as a fulcrum.

[0061] Next, as shown in Figures 17 and 18, the strand jacks 111 of the connecting members 110 pull the second suspension members 100 on both sides perpendicular to the bridge axis together, thereby moving each second suspension member 100 suspended from the first suspension member 90 inward in the direction perpendicular to the bridge axis to a position where it can avoid contact with the hanger cable 4 when moving in the bridge axis direction as described below.

[0062] 19, each installation device 60 is pulled by the wire 62 to move it to the next installation position along the main cable 3. At that time, since the second suspension member 100 has been moved to a position where it can avoid contact with the hanger cable 4, each of the first suspension member 90 and the second suspension member 100 passes beside the hanger cable 4.

[0063] Thus, according to this embodiment, a pair of first suspension members 90, each connected at its upper end to the end side beam portion 71 of the erection device main body 70, are positioned on both sides of the main cable 3 in the direction perpendicular to the bridge axis, and the suspended structure 5 before erection is connected to a second suspension member 100 connected to the lower end of each first suspension member 90 and extending in the direction perpendicular to the bridge axis, and the suspended structure 5 is lifted up to the erection position by each suspension member 90, 100.As a result, the load of the suspended structure 5, which is a heavy object, is not applied to the central side beam portion 72 of the erection device main body 70, and the strength of the central side beam portion 72 of the erection device main body 70 can be reduced accordingly.

[0064] That is, since only the end beam portions 71 of the erection device main body 70 need to have the strength to withstand the load of the suspended structure 5, bending moment due to the suspension load of the suspended structure does not occur in the entire erection device main body 70 as in the past, and the structure of the erection device main body 70 can be simplified and significantly reduced in weight. This reduces the required capacity of the equipment used to install and move the erection device 60, such as the tower-top crane used to assemble and dismantle the erection device main body 70 and the tower-top winch used to move the erection device 60 along the main cables 3, thereby improving workability and reducing costs. In particular, since the weight of the erection device main body 70 can be suppressed even when the spacing between the main cables 3 is wide, this is extremely advantageous in erecting such wide suspension bridges.

[0065] Furthermore, after connecting the hanger cable 4 suspended from the main cable 3 to the suspended structure 5, the connection between the lower end of the first suspension member 90 on the outside in the direction perpendicular to the bridge axis and the second suspension member 100 is released, and the second suspension member 100 connected to the first suspension member 90 on the inside in the direction perpendicular to the bridge axis is moved inward in the direction perpendicular to the bridge axis to a position where contact with the hanger cable 4 can be avoided when moving in the bridge axis direction.Therefore, when the erection device 60 suspending each suspension member 90, 100 is moved along the main cable to the erection position of the next suspended structure, each suspension member 90, 100 does not come into contact with the hanger cable 4 and can pass alongside the hanger cable 4 without hindrance. As a result, even in an installation method such as this embodiment in which the suspended structure 5 is lifted by a second suspension member 100 whose both longitudinal ends are connected to a pair of first suspension members 90 arranged on both sides of the main cable 3, the installation device 60 can be easily moved along the main cable 3 without the second suspension member 100 interfering with the hanger cable 4.

[0066] In this case, after connecting the hanger cable 4 and the suspended structure 5, the movable part 103, which is a component of the second suspension member 100, is shifted inward in the direction perpendicular to the bridge axis, thereby moving the center of gravity G of the second suspension member 100 to the connection position with the first suspension member 90 on the inside in the direction perpendicular to the bridge axis, and the connection between the lower end side of the first suspension member 90 on the outside in the direction perpendicular to the bridge axis and the second suspension member 100 is released.Therefore, after the connection between the second suspension member 100 and the other first suspension member 90 is released, the second suspension member 100 does not tilt, and the erection device 60 can be moved smoothly along the main cable 3 while maintaining the second suspension member 100 in a horizontal position.

[0067] Furthermore, the second suspension members 100 arranged on the main cable 3 sides of the suspension bridge 1 on both sides in the direction perpendicular to the bridge axis are connected by connecting members 110, and the second suspension members 100 are moved inward in the direction perpendicular to the bridge axis by pulling the second suspension members 100 together with the connecting members 110. Therefore, the left and right second suspension members 100 can be moved simultaneously with one connecting member 110, allowing work to be carried out efficiently.

[0068] Furthermore, since the first suspension member 90 is constructed of a strand jack 91 that pays out and repays a strand 92 whose lower end is connected to the suspended structure 5, the suspended structure 5 can be easily lifted by the strand jack 92.

[0069] In this case, the winding section 93 that winds up the upper end of the strand 92 is positioned above the main cable 3 and is provided on the running unit 80 on the main cable 3, so the weight of the winding section 93 is not added to the erection device main body 70, which has the advantage that the required strength of the erection device main body 70 is not increased by the winding section 93.

[0070] Furthermore, the erection device 60 is equipped with a running unit 80 that can travel on the main cable 3, and the running unit 80 supports the erection device main body 70 so that it can rotate freely around a horizontal axis extending perpendicular to the bridge axis. Therefore, the erection device main body 70 can be rotatably supported on the running unit 80 so that it is always horizontal due to its own weight, and the first suspension member 90 connected to the erection device main body 70 can always be kept vertical even if the erection device 60 tilts depending on the position along the length of the main cable 3. This allows the first suspension member 90 on the inside in the direction perpendicular to the bridge axis to rotate on a vertical plane, so that no horizontal force is applied to the first suspension member 90, allowing the first suspension member 90 to always rotate smoothly.

[0071] In the second embodiment, a pair of movable parts 103 are rotatably attached to the second hanging member 100, but the center of gravity may also be moved by a movable part that is slidably attached to the second hanging member 100.

[0072] Furthermore, in the first and second embodiments, one main cable 3 is provided on each end of the bridge in the direction perpendicular to the bridge axis, and two hanger cables 4 are used at each suspension position, but it is also possible to provide two main cables 3 on each end of the bridge in the direction perpendicular to the bridge axis, or to use one hanger cable 4 at each suspension position.

[0073] The first and second embodiments are examples of the present invention, and the present invention is not limited to those described in the above embodiments.

[0074] 1...Suspension bridge, 3...Main cable, 4...Hanger cable, 5...Suspension structure, 10...Erection device, 20...Erection device main body, 30...Traveling unit, 40...Suspension member, 42...Strand jack, 43...Strand, 44...Winding device, 50...Support mechanism, 51...Support member, 52...Hydraulic jack, 60...Erection device, 70...Erection device main body, 80...Traveling unit, 90...First suspension member, 91...Strand jack, 92...Strand, 93...Winding device, 100...Second suspension member, 103...Moving part, 110...Connecting member.

Claims

1. A method for erecting a suspension structure for a suspension bridge, comprising main cables arranged on both sides of the suspension bridge in the direction perpendicular to the bridge axis, multiple hanger cables arranged at intervals in the bridge axis direction, and a suspension structure suspended from the main cables by each hanger cable, the method comprising the steps of: using an erection device having an erection device main body formed to extend across each of the main cables in the direction perpendicular to the bridge axis, and being installed on the main cables so as to be movable in the direction of the bridge axis; connecting the upper ends of the suspension members supported by the erection device main body to the main cables, and connecting the suspension structure before erection to the lower ends of the suspension members; lifting the suspension structure to the erection position using the suspension members, and connecting the hanger cables suspended from the main cables to the suspension structure; releasing the connection between the lower ends of the suspension members and the suspension structure, and releasing the connection between the upper ends of the suspension members and the main cables; moving the suspension members supported by the erection device main body in the direction perpendicular to the bridge axis to a position where contact with the hanger cables can be avoided when moving in the bridge axis direction; A method for erecting a suspended structure for a suspension bridge, characterized by moving an erection device supporting a suspension member along a main cable to an erection position for the next suspended structure.

2. A method for erecting a suspended structure for a suspension bridge as described in claim 1, characterized in that the suspension member is moved in a direction perpendicular to the bridge axis by rotating a support member whose one end is rotatably connected to the erection device main body and whose other end is connected to the upper end of the suspension member.

3. A suspension structure erection device for erecting a suspension bridge suspension structure comprising main cables arranged on both sides of the suspension bridge in the direction perpendicular to the bridge axis, multiple hanger cables arranged at intervals in the direction of the bridge axis, and a suspension structure suspended from the main cables by each hanger cable, characterized by comprising: an erection device main body formed to extend across each of the main cables in the direction perpendicular to the bridge axis and installed on the main cables so as to be movable in the direction of the bridge axis; a suspension member whose upper end is detachably connected to the main cable and whose lower end can be connected to a suspension structure; and a support mechanism that supports the upper end of the suspension member and can move the suspension member in the direction perpendicular to the bridge axis when it has been released from connection with the main cable to a position where it can avoid contact with the hanger cables when moving in the direction of the bridge axis.

4. The suspension bridge suspended structure erection device according to claim 3, characterized in that the support mechanism has a support member rotatably connected at one end to the erection device main body, and a drive means for rotating the support member, and the upper end of the suspension member is connected to the other end of the support member.

5. The suspension bridge suspension structure erection device according to claim 3, characterized in that the suspension member is made up of a strand jack whose lower end feeds and retracts the strand connected to the suspension structure, and the upper end of the strand jack is configured to be detachable from the main cable side.

6. A method for erecting a suspension structure for a suspension bridge comprising main cables arranged on both sides of the suspension bridge in the direction perpendicular to the bridge axis, multiple hanger cables arranged at intervals in the direction of the bridge axis, and a suspension structure suspended from the main cables by each hanger cable, comprising the steps of: using an erection device having an erection device body formed to extend across each of the main cables in the direction perpendicular to the bridge axis and movably installed on the main cables in the direction of the bridge axis; arranging a pair of first suspension members, the upper ends of which are connected to the end sides of the erection device body in the direction perpendicular to the bridge axis, on both sides of the main cables in the direction perpendicular to the bridge axis; connecting the suspension structure before erection to second suspension members connected to the lower ends of each first suspension member and extending in the direction perpendicular to the bridge axis; lifting the suspension structure to the erection position using each suspension member; connecting the hanger cables suspended from the main cables to the suspension structure; releasing the connection between the lower end of the first suspension member on the outer side in the direction perpendicular to the bridge axis and the second suspension member; A method for erecting a suspended structure on a suspension bridge, characterized by: moving a second suspension member connected to a first suspension member on the inside in the direction perpendicular to the bridge axis inward in the direction perpendicular to the bridge axis to a position where contact with the hanger cable can be avoided when moving in the direction of the bridge axis; and moving the erection device to which each suspension member is connected along the main cable to the erection position of the next suspended structure.

7. A method for erecting a suspension structure on a suspension bridge as described in claim 6, characterized in that after connecting the hanger cable and the suspension structure, some components of the second suspension member are offset inward in the direction perpendicular to the bridge axis, thereby moving the center of gravity of the second suspension member to the connection position with the first suspension member on the inside in the direction perpendicular to the bridge axis, and releasing the connection between the lower end of the first suspension member on the outside in the direction perpendicular to the bridge axis and the second suspension member.

8. A method for erecting a suspended structure for a suspension bridge as described in claim 6, characterized in that the second suspension members arranged on the main cable sides of both sides of the suspension bridge in the direction perpendicular to the bridge axis are connected by a connecting member, and the second suspension members are moved inward in the direction perpendicular to the bridge axis by pulling the second suspension members together using the connecting members.

9. A suspension structure erection device for erecting a suspension bridge structure comprising main cables arranged on both sides of the suspension bridge in the direction perpendicular to the bridge axis, multiple hanger cables arranged at intervals in the bridge axis direction, and a suspension structure suspended from the main cables by each hanger cable, comprising: an erection device main body formed to extend across each of the main cables in the direction perpendicular to the bridge axis and installed on the main cables so as to be movable in the direction of the bridge axis; a pair of first suspension members arranged on both sides of the main cables in the direction perpendicular to the bridge axis, with their upper ends connected to the end sides of the erection device main body in the direction perpendicular to the bridge axis; and second suspension members connected to the lower ends of each first suspension member and formed to extend in the direction perpendicular to the bridge axis, to which the suspension structure is connected before erection; the second suspension member, which is released from the lower end side of the first suspension member on the outer side in the direction perpendicular to the bridge axis and is connected to the suspension member on the inner side in the direction perpendicular to the bridge axis, is configured to be movable inward in the direction perpendicular to the bridge axis to a position where it can avoid contact with the hanger cables when moving in the bridge axis direction. A suspension bridge suspension structure erection device characterized by the above.

10. A suspension bridge suspension structure erection device as described in claim 9, characterized in that the second suspension member is configured so that its center of gravity can be moved to a connection position with the first suspension member on the inside in the direction perpendicular to the bridge axis by displacing some of its components inward in the direction perpendicular to the bridge axis.

11. A suspension bridge suspension structure erection device as described in claim 10, characterized in that the second suspension member has a movable part that is rotatably connected to the end on the inside in the direction perpendicular to the bridge axis, and is configured so that the center of gravity can be moved inward in the direction perpendicular to the bridge axis by rotating the movable part and extending it toward the inside in the direction perpendicular to the bridge axis.

12. A suspension bridge suspension structure erection device as described in claim 9, characterized in that it is provided with connecting members that connect the second suspension members arranged on the main cable sides on both sides of the suspension bridge in the direction perpendicular to the bridge axis, and the connecting members are formed so as to move the second suspension members inward in the direction perpendicular to the bridge axis by pulling the second suspension members together.

13. The suspension bridge suspension structure erection device according to claim 9, characterized in that each of the first suspension members is a strand jack that feeds and rewinds a strand whose lower end is connected to the suspension structure.

14. A suspension bridge suspension structure erection device as claimed in claim 5 or 13, characterized in that the winding section that winds up the upper end of the strand is located above the main cable.

15. A suspension bridge suspension structure erection device as claimed in claim 3 or 9, characterized in that it is provided with a running unit capable of running on the main cable, and is configured so that the erection device main body is supported by the running unit so as to be rotatable around a horizontal axis extending perpendicular to the bridge axis.

Images