Method of erecting main girder between two existing main girders

Abstract

To provide a method of erecting a main girder including a plurality of main girder members connected to each other in a bridge axis direction between two existing main girders facing each other in a bridge width direction, in which a large work site is not required in an earthwork part on the back side of a bridge abutment with high safety.SOLUTION: A main girder member 12 is lifted from below an existing main girder 2 to a space between the two existing main girders 2. The lifted main girder member 12 is carried to the erection position in the bridge axial direction by a carrying truck 27. The main girder member 12 is temporarily supported by a device including temporary support devices 38, 39 supported by the existing main girder 2. The main girder members are connected to each other. The main girder members 12 connected to each other are switched from being temporarily supported by temporary support devices 38, 39 to support by a bearing 50 disposed on a lower structure 9.SELECTED DRAWING: Figure 17

Description

[Technical field]

[0001] The present invention relates to a method for erecting a main girder between two existing main girders facing each other in the width direction. [Background technology]

[0002] Regarding the erection of the main girders of a bridge, when a part below the installation location of the main girders is a river or another road, etc., and assembly work cannot be performed, the hand-stretching launching method, for example, is known (for example, Patent Document 1). The hand-stretching launching method is a method in which a hand-stretching machine and a part of the main girder that is connected to the hand-stretching machine are assembled in a work yard, and these are sent out using a launching device with the hand-stretching machine at the front, and when the hand-stretching machine reaches an intermediate bend that is a bridge pier or a temporary bridge pier, the main girder is added in the work yard, and the launching and addition are repeated, and when the main girder reaches the target position, the hand-stretching machine and the launching device are dismantled, and the main girder is placed on the support. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-176488 A Summary of the Invention [Problem to be solved by the invention]

[0004] In road bridges, two bridges are sometimes placed in parallel so that they can be used by vehicles going in opposite directions. When performing deck replacement work on two such bridges, it is possible to install a bridge girder between the two bridges and create a new road. While the deck replacement work on one bridge is being performed, vehicles can pass over the deck of the other bridge and the deck on the newly installed bridge girder, and while the deck replacement work on the other bridge is being performed, vehicles can pass over the deck of one bridge after the deck replacement and the deck on the newly installed bridge girder, so that the deck replacement work can be performed without or with minimal restrictions on vehicle traffic.

[0005] The hand-stretching launching method is considered as a construction method for erecting the main girder between two existing bridges. However, the space between the two existing bridges is too narrow to install a launching device, and it cannot be used as a work yard. For this reason, it is necessary to set up a work yard in the earthwork section behind the abutment. The hand-stretching machine and the main girder will be launched in the bridge axis direction at a position higher than the road surface, which will give a feeling of oppression to passengers of vehicles traveling on the existing bridge. In addition, after the launch is completed, the main girder will be lowered to a height supported by the bearings, and a safety measure will be required. Furthermore, it will be necessary to assemble the hand-stretching machine and install an intermediate bent, which is a temporary bridge pier to support the hand-stretching machine, which may extend the construction period.

[0006] In view of the above background, the present invention aims to provide a method for erecting a main girder, which includes multiple main girder members connected to each other in the bridge axis direction, between two existing main girders facing each other in the width direction, which does not require a large working site in the earthwork section behind the abutment and is highly safe. [Means for solving the problem]

[0007] In order to solve the above problem, one aspect of the present invention is a method for erecting a new main girder (10) including a plurality of main girder members (12) connected to each other in the bridge axis direction between two existing main girders (2) facing each other in the bridge width direction, the method comprising the steps of: lifting the main girder member from below the existing main girders to between the two existing main girders at a lifting position (14); transporting the lifted main girder member along the bridge axis direction to an erection position by a transporting device (25) attached to the two existing main girders; temporarily supporting the main girder member transported to the erection position by a device including temporary support devices (38, 39) supported on the existing main girders; connecting the main girder members transported to the erection position to each other; and switching the support of the connected main girder members from temporary support by the temporary support devices to support by bearings (50) arranged in the substructure (9) of the bridge.

[0008] According to this method, a part of the lower part of the existing bridge girder is used as a work space, so a large work site is not required for the earthwork section behind the abutment. In addition, the vertical movement distance of the main girder member after being transported to the erection position in the bridge axis direction is short, so safety is high. Compared to the case of using the hand-stretching method, the temporary facilities are small, and the construction period is shortened.

[0009] In the above aspect, the connecting step may include a step of connecting adjacent main girder members to each other to form a block connector (51) for each block including two or more main girder members (12) before the temporary supporting step, and a step of connecting adjacent block connectors to each other after the temporary supporting step and before the switching step.

[0010] According to this aspect, the multiple main girder members are temporarily supported by the temporary support devices as a block connection body for each block, thereby suppressing an increase in the number of temporary support devices.

[0011] In the above aspect, the temporary support devices (38, 39) may be configured to enable adjustment of the height of the main girder member (12), and the step of connecting the block connectors (51) to each other may include a step of pin-joining adjacent block connectors to each other, a step of adjusting the heights of the block connectors, and a step of finally tightening the pin-joined block connectors to each other after the step of adjusting the height.

[0012] According to this aspect, since the block connected bodies are in a pin-jointed state before being fully fastened to each other, the height of the block connected bodies can be easily adjusted by the temporary support device.

[0013] In the above aspect, the temporary support device (38, 39) may include a temporary support stand (38) that is attached to the existing main girder (2) and temporarily supports the main girder member (12) from below.

[0014] According to this aspect, since the temporary support frame supports the main girder member from below, the support of the main girder member can be safely and easily transferred from the transport cart to the temporary support frame.

[0015] In the above-mentioned aspect, the transporting device (25) may include a rail (26) supported on the existing main girder (2) and a transport cart (27) that runs on the rail and holds the main girder member (12).

[0016] According to this aspect, the main girder members are transported by the transport cart running on the rails, so that vertical displacement of the main girder members during transportation is suppressed.

[0017] In the above aspect, the temporary support devices (38, 39) may include a temporary support stand (39) that travels on the rails (26) and temporarily supports the main girder member (12) from above.

[0018] According to this aspect, the temporary support frame runs on a common rail with the transport cart, making it easy to position the temporary support frame on the existing main girder so as not to impede the travel of the transport cart.

[0019] In the above embodiment, the two existing main girders (2) may be main girders of different existing bridges (1).

[0020] According to this aspect, even if there are users of the existing bridge, the main girder members move in the bridge axis direction at approximately the same height as the existing main girders, making them difficult to see by users of the existing bridge and thus not giving users of the existing bridge a feeling of oppression. Effect of the Invention

[0021] According to the above aspects, in a method for erecting a new main girder including multiple main girder members connected to each other in the bridge axis direction between two existing main girders facing each other in the width direction, a highly safe method can be provided that does not require a large work site for the earthwork section behind the abutment. Furthermore, in an aspect in which a new main girder is erected between two existing bridges facing each other in the bridge width direction, a main girder erection method that does not give a feeling of oppression to users of the existing bridge can be provided. [Brief description of the drawings]

[0022] [Figure 1] Fig. 1 is a perspective view showing a bridge according to an embodiment (A: before construction, B: after construction) [Diagram 2] FIG. 1 is an explanatory diagram showing an installation method according to an embodiment (a diagram showing an overall image); [Diagram 3] FIG. 1 is an explanatory diagram showing an installation method according to an embodiment (installation of a temporary support stand); [Figure 4] An explanatory diagram showing the installation method according to the embodiment (transportation of the first main girder member) [Diagram 5] An explanatory diagram showing the installation method according to the embodiment (transportation of the second main girder member) [Figure 6] An explanatory diagram showing the installation method according to the embodiment (connection of the main girder members in the first block) [Figure 7] FIG. 1 is an explanatory diagram showing an installation method according to an embodiment (supported by a temporary support stand); [Figure 8] An explanatory diagram showing the installation method according to the embodiment (support by temporary support frame, transportation of main girder members of the second block) [Figure 9] An explanatory diagram showing the installation method according to the embodiment (connection of the main girder members in the second block, pin joints between block connectors) [Figure 10] An explanatory diagram showing the installation method according to the embodiment (after transportation for one span) [Figure 11] An explanatory diagram showing the installation method according to the embodiment (final tightening between blocks) [Figure 12] FIG. 1 is an explanatory diagram showing an installation method according to an embodiment (jacking up). [Figure 13]FIG. 1 is an explanatory diagram showing an installation method according to an embodiment (jacking down). [Figure 14] FIG. 1 shows a gate-type lifting equipment according to an embodiment (A: view from the bridge axis direction, B: view from the bridge width direction) [Figure 15] A diagram showing a transport device according to an embodiment (A: view from the bridge axis direction, B: view from the bridge width direction (illustration of the existing bridge in the foreground is omitted)) [Figure 16] FIG. 1 is a diagram showing a temporary support device according to an embodiment (as viewed from the bridge axis direction); [Figure 17] FIG. 5 is a schematic perspective view showing an installation method according to the embodiment (a perspective view of a part of FIG. 4); DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, an installation method according to an embodiment will be described with reference to the drawings.

[0024] This embodiment is applied to a case where there are two existing bridge superstructures 1 facing each other in the bridge width direction, as shown in FIG. 1(A). Each of the existing bridge superstructures 1 includes a plurality of existing main girders 2, 3 (among the plurality of main girders of each existing bridge superstructure 1, the one arranged closest to the other existing bridge superstructure 1 is indicated by the reference symbol "2", and the others are indicated by the reference symbol "3"), a cross girder 4 and a paired structure 5 connecting the plurality of existing main girders 2, 3 to each other, a deck 6 provided on the existing main girders 2, 3, a pavement layer 7 provided on the deck 6, and a guard fence 8. The existing main girders 2, 3 include I-shaped steel. Therefore, the two existing main girders 2 are arranged adjacent to each other with a space between them in the bridge width direction. The deck 6 is formed of concrete, and the pavement layer 7 is formed of asphalt. The distance between the two existing main girders 2 in the bridge width direction is preferably greater than the distance between existing main girders 2, 3 arranged adjacent to each other within a single existing bridge superstructure.

[0025] As shown in FIG. 1(B), a new main girder 10 is erected between two existing main girders 2 facing each other. In the illustrated example, the new main girder 10 is a steel box girder, but it may be a steel girder of another shape such as an I-shape, or may be a concrete girder. After erecting the new main girder 10, a cross girder 4 is provided between the new main girder 10 and the existing main girder 2, and the deck 6 laid on the new main girder 10 is used to replace the deck 6 of the existing bridge superstructure 1. After the replacement work is completed, a protective fence 11 that serves as a central median is installed on the new main girder 10, and the left and right parts of the fence may be used as a roadside strip or a roadway.

[0026] As shown in FIG. 2, the two existing bridge superstructures 1 are erected on a common substructure 9 including piers and abutments. Therefore, as shown in FIG. 17, the substructure 9 extends between the two existing bridge superstructures 1. As shown in FIG. 1 and FIG. 2, the new main girder 10 includes a plurality of main girder members 12 connected to each other in the bridge axis direction. The main girder members 12 are manufactured in a factory and then transported by a trailer 13 or the like to a lifting position 14 provided below the existing bridge superstructure 1. Only one lifting position 14 is required, and the main girder member 12 lifted up to between the two existing main girders 2 here is moved in the bridge axis direction and transported to the erection position. In FIG. 2, the main girder member 12 is lifted on the right side of the paper and transported toward the left side of the paper, and the new main girder 10 is constructed in order from the left side of the paper.

[0027] The erection of the new main girder 10 includes hoisting the main girder members 12, transporting the main girder members 12 along the bridge axis direction, connecting and temporarily supporting the main girder members 12, and switching from temporary support of the main girder members 12 to support by bearings 50 (see Figure 13). The erection of the new main girder 10 is carried out by repeating construction from an already constructed portion of one substructure 9 or new main girder 10 onto the other substructure 9 or beyond it by a specified distance (hereinafter referred to as the "construction unit section").

[0028] The main girder member 12 is lifted by a portal-type lifting equipment 15 shown in FIG. 14. The sides of the two existing bridge superstructures 1 facing each other in the bridge width direction are used for the erection work of the new main girder 10. For this reason, the existing guard fence 8 (see FIG. 1) is removed from these sides, and a guard fence 16 for vehicles, such as a wall railing, is installed on the inside of each existing bridge superstructure 1 in the bridge width direction. A work enclosure 17 is installed on the guard fence 16, including a single pipe (not shown) attached to the guard fence 16 so as to extend upward, and a mesh sheet (not shown) attached to the single pipe. In this way, a work space is provided on the deck 6 on the outside of the guard fence 16 in the bridge width direction.

[0029] The portal-type lifting equipment 15 is installed in the working space of the deck 6 so as to straddle the two existing main girders 2. The portal-type lifting equipment 15 includes a base member 18 arranged on the deck 6 of each existing bridge superstructure 1 and extending in the bridge axis direction, two support members 19 erected on each base member 18, two first beam members 20 bridged between the upper ends of the two support members 19 adjacent to each other in the bridge width direction, two second beam members 21 bridged between the centers of the two first beam members 20 in the bridge width direction, two third beam members 22 bridged between the two second beam members 21 and arranged to extend in the bridge width direction while being spaced apart from each other in the bridge axis direction, and an electric chain block 23 attached to each of the third beam members 22. The base member 18 and the first to third beam members 20, 21, 22 are made of H-shaped steel, and the support member 19 is made of square bent steel. The electric chain block 23 engages with a hoist 24 attached to the upper part of the main girder member 12 to hoist the main girder member 12. The portal lifting equipment 15 may further include a connecting member 54 that connects the vertical middle parts of the two support members 19 aligned in the bridge axis direction to each other.

[0030] Fig. 15 shows a transport device 25 for transporting the main girder member 12 hoisted by the portal hoisting equipment 15 (see Fig. 14) along the bridge axis direction. The transport device 25 includes rails 26 installed in the working space of the deck 6 of each existing bridge superstructure 1 so as to extend in the bridge axis direction, and a transport cart 27 arranged to straddle the two existing main girders 2 and run on the pair of rails 26. The main girder member 12 hoisted by the portal hoisting equipment 15 is transferred to the transport cart 27 together with the hoist balance 24.

[0031] The rail 26 preferably includes an H-shaped steel 26a placed on the deck 6 and a rail material 26b (for example, a light rail (22 kg rail) specified in JIS E1103) fixed to the upper surface of the H-shaped steel 26a (see Figure 14).

[0032] The transport cart 27 includes wheels 28 that run on the rails 26, a chassis 29 that rotatably supports the wheels 28, a drive unit 30 that is placed on the chassis 29 and drives the wheels 28, a control unit 31 that is placed on the chassis 29 and controls the drive unit 30, and a hoisting bracket 32 ​​attached to the chassis 29. The transport cart 27 is a self-propelled cart.

[0033] The wheels 28 are arranged at the four corners of the chassis 29 in a plan view, with two wheels provided at each corner, one at the front and one at the rear (aligned in the bridge axis direction).

[0034] The chassis 29 includes two lower beam members 33 arranged on the wheels 28 facing each other in the bridge width direction and extending in the bridge width direction, two upper beam members 34 bridged between the two lower beam members near the center in the bridge width direction, a collapse prevention member 35 bridged between the two upper beam members 34, and a tie member 36 bridged in the vicinity of the wheels 28 at two corners arranged apart in the bridge axis direction. The lower beam member 33, the upper beam member 34, and the tie member 36 are made of H-shaped steel. The upper beam member 34 is connected to the lower beam member 33 via an adjustment member 37 including a spherical joint that can rotate in all directions, and the collapse prevention member 35 suppresses the independent displacement of the two upper beam members 34 relative to the lower beam member 33, and is made of a steel bar.

[0035] The driving unit 30 includes a generator and drives the wheels 28 at two corners located on one side in the bridge axis direction among the four corners. The wheels 28 at the other corner on the other side in the bridge axis direction are driven wheels.

[0036] The control unit 31 includes a computer that controls the drive unit 30. The control unit 31 may include an operator operated by an operator in addition to or instead of the computer.

[0037] The hoisting fittings 32 are attached to the upper beam members 34, and are provided in pairs so as to be aligned in the bridge width direction and spaced apart from each other in the bridge axis direction. The hoisting fittings 32 engage with the hoist balance 24 connected to the upper surface of the main girder member 12, whereby the main girder member 12 is held on the transport cart 27. In this state, the transport cart 27 travels on the rails 26, whereby the main girder member 12 is transported in the bridge axis direction while being maintained at approximately the same height as the existing main girder 2.

[0038] The main girder member 12 transported by the transport device 25 to the installation position, which is the position where the main girder member 12 is to be installed or a position nearby, is supported by a temporary support frame 38 and a temporary support frame 39 shown in Fig. 16. The temporary support frame 38 and the temporary support frame 39 are collectively referred to as temporary support devices 38, 39.

[0039] The temporary support frame 38 is provided so as to straddle the two existing main girders 2 at the lower side, and temporarily supports the main girder member 12 from below. The temporary support frame 38 includes a fixing member 40 fixed to the lower flange of each of the two existing main girders 2 by a fastener (not shown), a frame beam member 41 extending in the bridge width direction and connected to the lower surface of the corresponding fixing member 40 at both ends in the bridge width direction, a jack 42 fixed to the upper surface of the frame beam member 41, and a main girder support member 43 attached to the upper surface of the jack 42 so as to extend in the bridge width direction, on which the main girder member 12 is placed. The frame beam member 41 and the main girder support member 43 are made of H-shaped steel. Both ends in the bridge width direction of the frame beam member 41 are connected to the fixing member 40 via a pin joint 44 that can rotate around the bridge axis direction.

[0040] The temporary support frame 39 is provided so as to straddle the two existing main girders 2 at the top, and temporarily supports the main girder member 12 from above. The temporary support frame 39 includes a pair of wheels 45 that run on the two rails 26, two support parts 46 that rotatably support the corresponding wheels 45, a frame beam member 47 that is spanned between the two support parts 46 and extends in the bridge width direction, and a hoisting bracket 49 that is attached to the frame beam member 47 via a height adjustment device 48 and engages with the hoisting balance 24 to which the main girder member 12 is attached. The frame beam member 47 is made of H-shaped steel. The height adjustment device 48 can adjust the vertical position of the hoisting bracket 49 relative to the frame beam member 47, and includes a center hole jack and a ram chair. The temporary support frame 39 is supported by the existing main girder 2 via the rail 26 and the deck 6.

[0041] Figures 3 to 13 show the left span in Figure 2, with the illustration of the one of the two existing bridge superstructures 1 located on the near side of the page omitted, and Figure 17 is a perspective view of part of Figure 4. Below, with reference to Figures 2 to 13 and Figure 17, the procedure for erecting a new main girder 10 (see Figure 1) in one construction unit section will be explained.

[0042] Workers set up multiple temporary support cradles 38 in one construction unit section (Figure 3). Multiple temporary support cradles 39 are stocked together near the end of the construction unit section opposite the side where the portal lifting equipment 15 (see Figure 2) is placed.

[0043] Next, the worker uses the portal lifting equipment 15 to lift the main girder member 12 up to between the two existing main girders 2 (see the right side of the paper in FIG. 2). The lifted main girder member 12 is placed at a position slightly higher than the height of the newly installed main girder 10 (see FIG. 1) when the installation is completed. The worker transfers the lifted main girder member 12 to the transport cart 27 and transports the main girder member 12 to the installation position using the transport cart 27. Two transport carts 27 are prepared. First, the worker transports the first main girder member 12, which is located at the end of the construction unit section opposite the installation position of the portal lifting equipment 15, to the installation position using the first transport cart 27 (FIGS. 4 and 17), and then transports the adjacent second main girder member 12 to the installation position using the second transport cart 27 (FIG. 5). Once the two main girder components 12 have been transported to the installation location, workers connect (finally tighten) these two main girder components 12 while suspended from the transport cart 27 using fastening members (not shown) to form a block connector 51 (Figure 6).

[0044] Next, the worker lowers the block connected body 51 from the transport cart 27 and places it on the temporary support frame 38, releases the engagement of the transport cart 27 with the block connected body 51, and moves the two transport carts 27 toward the installation location of the portal lifting equipment 15 (FIG. 7). The block connected body 51 is temporarily supported by the temporary support frame 38 near both ends in the bridge axis direction. In the block connected body 51 shown in FIG. 7, one end in the bridge axis direction is located on the substructure 9, so this one end is temporarily supported by the support 50 arranged on the substructure 9 instead of the temporary support frame 38. Next, the worker moves the temporary support frame 39 and uses the two temporary support frames 39 to suspend the block connected body 51 via the hoist 24 (FIG. 8). Therefore, the block connected body 51 is temporarily supported by the temporary support frame 39 in addition to the temporary support frame 38. It is preferable that the temporary support cradles 39 temporarily support the block connected bodies 51 at a position offset in the bridge axis direction from the temporary receiving cradles 38. The temporary support cradles 39 move on the rails 26 and cannot move over other temporary support cradles 39, so among the stocked temporary support cradles 39, those arranged on the opposite side to the transport cart 27 are used to temporarily support the block connected bodies 51 in order, and unused temporary support cradles 39 are placed between the used temporary support cradles 39 and the transport cart 27.

[0045] As described above, the two main girder members 12 are treated as one block, and the processes of lifting and transporting the main girder members 12, connecting the two main girder members 12 to each other, and temporarily supporting the block connected body 51 including the two main girder members 12 are repeated (Figs. 9 and 10). Adjacent block connected bodies 51 are temporarily connected at the upper edges of the adjacent ends in the bridge axis direction by pin joints that are rotatable around an axis in the bridge width direction.

[0046] Once the block connectors 51 have been placed throughout the entire construction unit section, workers use the jacks 42 (see Figure 16) on the temporary support stand 38 and the height adjustment devices 48 (see Figure 16) on the temporary support stand 39 to adjust the height of the block connectors 51, and connect adjacent block connectors 51 to each other with fasteners (not shown) to form a section connector 52 (Figure 11) in which all of the main girder members 12 within the construction unit section are fully fastened to each other.

[0047] Thereafter, the worker jacks up the section connector 52 using the jack 53 placed on the upper surface of the substructure 9, and releases the temporary support of the section connector 52 by the temporary support frame 38 and the temporary support frame 39 (FIG. 12). Next, the worker jacks down the section connector 52 using the jack 53 so that it is supported by the supports 50 (FIG. 13). The worker removes the temporary support frame 38, moves the temporary support frame 39 along the rails 26, and connects the newly installed section connector 52 to the existing section connector 52, if there is another existing section connector 52. By repeating the construction of the section connectors 52 as described above, the new main girder 10 (see FIG. 1) is erected.

[0048] The effects of the erection method according to the embodiment will be described. The erection method according to the embodiment uses a part of the lower part of the existing bridge superstructure 1 as a work space, so that a large work site is not required for the earthwork part behind the abutment.

[0049] The main girder members 12 are transported by a transport cart 27 running on rails 26 supported on the existing main girders 2 via the deck 6, so vertical displacement of the main girder members 12 during transportation is suppressed. Since the main girder members 12 move in the bridge axis direction at approximately the same height as the existing main girders 2, they are difficult to see from users of the existing bridge superstructure 1 and do not give users of the existing bridge superstructure 1 a feeling of oppression.

[0050] The vertical movement distance of the section connector 52 including the main girder member 12 after it has been moved to the position to be erected in the bridge axis direction is smaller than when the hand-stretching launching method is used and the section connector 52 is launched from the rear face of the abutment, so the safety of the work is high. Also, compared to the hand-stretching launching method, no large-scale temporary facilities such as a hand-stretching machine or intermediate vents are required, so the temporary facilities can be smaller and the construction period can be shortened.

[0051] The main girder member 12 is temporarily supported by the temporary support devices 38, 39 as a block connected body 51 for each block, thereby suppressing an increase in the number of temporary support devices 38, 39.

[0052] Since the block connectors 51 are in a pin-jointed state before being fully tightened together, the height of the block connectors 51 can be easily adjusted by the jack 42 of the temporary receiving stand 38 and the height adjustment device 48 of the temporary supporting stand 39.

[0053] Since the temporary support stand 38 supports the block connected body 51 including the main girder member 12 from below, the support of the block connected body 51 can be transferred from the transport cart 27 to the temporary support stand 38 safely and easily.

[0054] Since the block connector 51 or the section connector 52 is temporarily supported from below by the temporary support stand 38 and from above by the temporary support stand 39, it is more stable than if it were temporarily supported by only one of the temporary support stand 38 or the temporary support stand 39.

[0055] Since the temporary support platform 39 runs on the same rails 26 as the transport cart 27 , it is easy to position the temporary support platform 39 on the deck 6 so as not to impede the travel of the transport cart 27 .

[0056] By the temporary support frame 39 temporarily supporting the block connector 51 at a position offset in the bridge axis direction from the temporary receiving frame 38, the block connector 51 is stabilized and the height of the block connector 51 can be easily adjusted.

[0057] Although the description of the specific embodiment is finished above, the present invention is not limited to the above embodiment and modified examples, and can be widely modified and implemented. The existing main girder 2 may be two main girders already installed in a bridge to be newly installed, and the new main girder 10 may be a main girder arranged between the two main girders already installed. For example, when it is necessary to shorten the installation period of the bents under the girders due to process constraints, the two main girders are installed in advance by a conventional construction method using the bents, and then the bents are removed and the new main girder 10 is installed between the two main girders by the present invention. In addition, the present invention may be applied to the widening construction of two existing bridge superstructures 1, instead of the deck replacement construction of two existing bridge superstructures 1.

[0058] As the temporary support devices 38, 39, only one of the temporary support frame 38 and the temporary support frame 39 may be used. The temporary support frame 39 may be fixed to the deck 6 or the existing main girder 2 instead of running on the rails 26.

[0059] The number of main girder members 12 constituting one block may be three or more, and the main girder members 12 may be supported by the temporary support devices 38, 39 one by one, rather than by block.

[0060] The section connector 52 may be transferred from the temporary support devices 38, 39 to the support 50 by using the jack 42 of the temporary support stand 38 or the height adjustment device 48 of the temporary support stand 39 (see FIG. 16) instead of or in addition to the jack 53 arranged on the substructure 9. In this case, the temporary support by the temporary support stand 38 and the temporary support stand 39 is released after the section connector 52 is placed on the support 50. Also, the temporary support by the temporary support stand 38 and the temporary support stand 39 may be released after the section connector 52 is connected to another section connector 52 that has already been installed. [Explanation of symbols]

[0061] 1: Existing bridge superstructure 2: Existing main girder 6: Floor slab 9: Substructure 10: New main girder 12: Main girder member 14: Lifting position 15: Gate-type lifting equipment 25: Transport device 26: Rail 27: Transport cart 38: Temporary support stand (temporary support device) 39: Temporary support stand (temporary support device) 44: Pin joint 50:Support 51: Block connection body 52: Interval Concatenation 53: Jack

Claims

1. A method for erecting a new main girder including a plurality of main girder members connected to each other in a bridge axis direction between two existing main girders facing each other in a bridge width direction, comprising: At a lifting position, lifting the main girder member from below the existing main girder to between the two existing main girders; A step of transporting the lifted main girder member along the bridge axis direction to an erection position by a transport device attached to the two existing main girders; A step of temporarily supporting the main girder member transported to the installation position by an apparatus including a temporary support device supported on the existing main girder; connecting the main girder members transported to the installation position to each other; and switching the interconnected main girder members from temporary support by the temporary support device to support by bearings disposed in the bridge substructure.

2. The step of connecting includes: a step of forming a block connected body by connecting adjacent main girder members to each other for each block including two or more main girder members before the temporary supporting step; The method according to claim 1 , further comprising the step of: connecting the adjacent block connectors to each other after the temporary supporting step and before the switching step.

3. The temporary support device is configured to be able to adjust the height of the main girder member, The step of connecting the block connectors to each other includes: a step of pin-joining the adjacent block connections to each other; adjusting the height of the block connector; The method of claim 2 , further comprising the step of tightening the pin-jointed block connections together after the step of adjusting the height.

4. The method according to claim 1 , wherein the temporary support device includes a temporary support stand that is attached to the existing main girder and temporarily supports the main girder member from below.

5. The conveying device is A rail supported on the existing main girder; and a transport car running on the rails and holding the main girder members.

6. The method according to claim 5 , wherein the temporary support device includes a temporary support stand that travels on the rail and temporarily supports the main girder member from above.

7. The method according to any one of claims 1 to 6, wherein the two existing main girders are main girders of different existing bridges.

Images