A method for reverse construction of a continuous steel truss web-plate truss double-layer composite rotating bridge

Abstract

This invention discloses a reverse construction method for a continuous steel truss web-plate truss double-layer composite rotating bridge. The method involves first erecting a support platform parallel to the railway direction to assemble all the steel structures, then sequentially pouring and tensioning the steel strands of the concrete beam segments, followed by dismantling the support platform and installing temporary steel supports for the rotation construction. This invention enables the safe and efficient hoisting and installation of the upper-layer giant steel truss web-plate truss composite structure, thus successfully completing the construction of the entire continuous steel truss web-plate truss double-layer composite rotating bridge spanning the railway. Simultaneously, by connecting the cast-in-place support formwork to the upper-layer steel truss structure, the reverse beam support function of the upper-layer steel truss is fully utilized during the pouring of the lower-layer concrete beams.

Description

Technical Field

[0001] This invention relates to the field of construction technology for rotating bridges, and in particular to a reverse construction method for a continuous steel truss web-plate truss double-layer combined rotating bridge. Background Technology

[0002] Bridge plane rotation construction technology is a new bridge construction process that has emerged in recent years. Because its rotation construction relies on the structure itself to rotate into place, it has minimal impact on the normal traffic flow of existing traffic routes under the bridge. Therefore, it is frequently used in the construction of highway bridges crossing existing railways. However, all the plane rotation bridges that have been built or are under construction at home and abroad are T-shaped single-layer rotation bridge structures. In order to reduce land acquisition and demolition and save land and bridge construction costs, for the new design of a continuous steel truss web-plate truss double-layer combined rotation bridge structure for this project, what new construction technologies should be adopted, especially given the severe limitation of construction site on the side near the existing railway line, and how to design the construction plan for this rotation bridge? These are urgent problems that all bridge construction project personnel need to solve.

[0003] When building bridges on the ground, construction usually proceeds sequentially from the foundation and lower levels to higher levels. During the construction process, the lower structure often serves as a support platform for the construction of the upper structure. However, for the new design of a continuous steel truss-plate truss double-layer composite rotating bridge structure that crosses a railway, especially when there is no crane space available on the side near the existing railway, if the lower T-shaped concrete bridge deck is poured first, the hoisting and construction of the upper steel truss and steel bridge deck on the side near the existing railway will become very difficult. The existing crawler crane technology will be unable to achieve hoisting and construction over large horizontal distances. Summary of the Invention

[0004] To overcome the above-mentioned technical difficulties, the present invention provides a method for reverse construction of a continuous steel truss web-plate truss double-layer composite rotating bridge. The method involves first erecting a support platform parallel to the railway direction to assemble all the steel structures, then pouring and tensioning the steel strands of the concrete beam segments in sections, and finally dismantling the support and installing temporary steel supports for the rotation construction.

[0005] A continuous steel truss web-plate truss double-layer composite rotating bridge: adopts a T-shaped long cantilever continuous steel truss web-plate truss composite structure, arranged in a continuous span; the lower layer adopts ribbed concrete beams, and the upper layer adopts steel truss beams; a total of 3 main trusses are arranged in the transverse direction, and the longitudinal direction is a Warren-type main truss.

[0006] The main construction process of the reverse construction method for the double-layer combined rotating bridge includes:

[0007] (1) On the construction site on the side parallel to the existing railway direction, first carry out the construction of bored piles, the foundation pit protection works of the bridge pier foundation, the bridge pile foundation and the lower abutment, the backfilling construction from the foundation pit to the top of the abutment, install the rotation system, pour the upper abutment of the main pier and construct the bridge pier cap beam, and at the same time construct the foundation of the side pier and the bridge pier and cap beam.

[0008] (2) Level the construction site, harden the support foundation and material storage area; in the early stage of construction, all soft soil and silt in the site are excavated and replaced with rubble, the bearing capacity of the foundation is not less than 200KPa, the steel beam storage area is hardened with 20cm thick C30 concrete as a whole; the crawler crane travel foundation is reinforced; the steel truss beam steel support foundation adopts 8.5m*8.5m convex C35 reinforced concrete enlarged foundation, and the cast-in-place beam plate buckle support foundation adopts 25cm thick C30 concrete.

[0009] (3) Temporary supports are set up for the steel truss nodes corresponding to the steel truss supports. The main pier is divided into 6 rows of temporary support supports on both sides, with 3 sets of supports in each row. The side piers on both sides are numbered from small to large as 1-6. The supports of nodes 1, 2, 3 and 5 are assembled by connecting 4 steel pipes. The supports of nodes 4 and 6 are made of 2 steel pipe concrete supports to consider the increase of reaction force during the demolition process. A total of 24 sets of steel pipe temporary supports and 12 sets of steel pipe concrete temporary supports are arranged. The top column of the steel pipe concrete support is sealed with steel plate welding. A sand bucket is set on the top of the column. The crossbeam is made of steel plate welding. The 6th support that is demolished last needs to be lowered by 4 jacks. The upper structure of the steel pipe is a crossbeam. Three 56 I-beams and thick pads are set on the top of the crossbeam.

[0010] (4) The specific hoisting sequence and steps of the upper steel truss girder of the double-layer combined rotating bridge are as follows:

[0011] 1) Install the first section of the lower horizontal bracing: The first crawler crane to arrive will first install the lower horizontal bracing at the position of the main pier and the No. 1 node support pier near the existing line section. Then the second crawler crane will arrive, and the two crawler cranes will simultaneously install the lower horizontal bracing from the middle to both sides. The lower horizontal bracing is a temporary member made of steel members and needs to be removed before the concrete section is poured; 2) Install the first section of the upper chord and main truss diagonal members: First install the upper chord and the corresponding main truss diagonal members of the main pier and the No. 1 node support pier. Then the two crawler cranes will simultaneously install the remaining upper chord and main truss diagonal members from the middle to both sides;

[0012] 3) Install the first upper horizontal and longitudinal bracing and bridge deck: After the upper chord and main truss diagonal bracing between the main pier and the No. 1 node support pier are installed, start installing the corresponding upper horizontal and longitudinal bracing and the corresponding bridge deck, and install the components from the middle to both sides.

[0013] 4) Install the second section of lower chord, upper chord, diagonal brace, upper horizontal longitudinal brace, and bridge deck: The installation sequence is also from the middle to both sides.

[0014] The principle of steel beam assembly and installation is as follows: from bottom to top, first the horizontal plane, then the vertical plane, to form a stable triangular structure as soon as possible, and then install the horizontal plane; before assembly, the node plates, assembly plates, filler plates, and high-strength bolts should be placed near each node.

[0015] (5) Erect a cast-in-place full-span scaffold and pour and tension the lower concrete beams in sections from the middle to both sides.

[0016] (6) Temporary consolidation of the main pier: Temporary supports and temporary anchorages are installed on the top of the main pier to bear the maximum vertical support reaction at the mid-support point. The temporary supports are installed on the pier and have a thickness of 0.8m from the bottom of the beam to the top of the cap beam. Each temporary support has steel bars embedded in the top of the pier and the cast-in-place beam. The material of the temporary supports is C60 concrete. After the main bridge is rotated, the temporary consolidation of the main pier can be removed only after the supports at both ends are installed. The removal is carried out by wire saw cutting.

[0017] (7) Construct the outer maintenance passage railing on the lower level; construct the outer anti-collision guardrails and anti-throw nets on the upper and lower levels.

[0018] (8) Unload the support at multiple points and in stages to allow the cantilever structure to deflect naturally until all deflection occurs. Note that the longitudinal overturning stability of the cantilever structure must be guaranteed during the unloading process.

[0019] (9) When installing temporary steel supports beside the pier, it is necessary to ensure that the temporary steel supports do not restrict the symmetrical deflection of the cantilever structure. After the cantilever deflection is completed, ensure that the steel supports are tightly fitted to the bottom of the beam without any gaps. The support system only provides vertical support to the main beam, and the horizontal force is borne by the tie rods within the support system. The construction party must develop a specific construction plan for this temporary support system.

[0020] (10) Remove all cast-in-place supports.

[0021] (11) Rotation construction: Rotate the rotating beam segment 81.1° counterclockwise to the completed bridge position and lock it. Then construct the post-cast section of the rotation system.

[0022] (12) After the body is rotated into place and locked, jacks are placed on the top surface of the lower layer cap beam of the side pier to lift the beam ends on each side of the main beam. The lifting force and the lifting displacement are controlled simultaneously, and the error must be controlled within 5%.

[0023] (13) Install the side pier support, remove the lifting jack, and complete the system conversion.

[0024] (14) Remove the temporary auxiliary facilities for rotation, release the temporary pier and beam fixing measures, and install the main pier support.

[0025] (15) In conjunction with the construction progress of adjacent sections, construct the upper pier columns and cap beams of the side piers, and the ancillary works of the entire bridge, and finally complete the acceptance and open the bridge to traffic.

[0026] As a preferred option, after erecting the full-span cast-in-place scaffold and before pouring the lower concrete beam, a steel tie rod device can be used to connect the cast-in-place scaffold formwork with the upper steel truss structure. This can effectively reduce the construction risk of slippage and instability of the high-support formwork of the full-span scaffold and give full play to the anti-beam support role of the upper steel truss during the pouring of the lower concrete beam.

[0027] Preferably, the steel tie rod device is evenly arranged on the lower chord of the upper steel truss structure, and the arrangement interval can be set to a horizontal spacing of 1.2-1.5 meters.

[0028] As a preferred option, during the removal of temporary supports, the temporary supports at positions 1, 3, and 5 should be removed first, followed by the temporary supports at positions 2 and 4. Then, temporary steel supports should be installed next to the main pier, ensuring that the temporary steel supports do not restrict the symmetrical deflection of the cantilever structure. After the cantilever deflection is completed, the steel supports should be tightly fitted to the bottom of the beam without any gaps. The temporary steel support structure only provides vertical support to the main beam, and the horizontal force is borne by the tie rods within the support system. Temporary support No. 6 and all other cast-in-place supports should be removed.

[0029] The beneficial effects of the reverse construction method of this invention are as follows: When constructing a new scheme for a continuous steel truss-plate girder double-layer composite rotating bridge structure spanning a railway near the existing railway, even with very limited crane space on the existing railway side, the safe and efficient hoisting and installation of the upper giant steel truss-plate girder composite structure was achieved, thus successfully completing the construction of the entire continuous steel truss-plate girder double-layer composite rotating bridge spanning the railway. Simultaneously, by connecting the cast-in-place support formwork to the upper steel truss structure, the reverse beam support function of the upper steel truss during the pouring of the lower concrete beams was fully utilized. Attached Figure Description

[0030] Figure 1 Schematic diagram of the first section of the upper steel truss of the rotating bridge during hoisting construction;

[0031] Figure 2 Schematic diagram of the second section of the upper steel truss of the rotating bridge during hoisting construction;

[0032] Figure 3 : Elevation diagram of the upper steel truss structure of the rotating bridge;

[0033] Figure 4 Schematic diagram of the cast-in-place concrete beam and support structure of the lower rib plate type of the rotating bridge;

[0034] Figure 5 Schematic diagram of the lower rib-type concrete beam support for the demolition of a rotating bridge;

[0035] Figure 6 Schematic diagram of the dismantling of supports at nodes 1, 3, and 5 of the rotating bridge;

[0036] Figure 7 : Schematic diagram of the dismantling of supports at nodes 2 and 4 of the rotating bridge;

[0037] Figure 8 Schematic diagram of temporary steel support structure for the installation of a rotating bridge;

[0038] Figure 9 Schematic diagram of the support structure at node 6 of the rotating bridge being dismantled;

[0039] Figure 10 Schematic diagram of the bridge after rotation;

[0040] Among them: 1. Lower horizontal bracing, 2. Upper horizontal longitudinal bracing, 3. Main truss diagonal bracing, 4. Upper chord, 5. Crane, 6. Temporary support, 7. Bridge deck, 8. Main pier, 9. Full-span scaffolding, 10. Lower concrete beam, 11. Temporary steel support, 12. Side pier. Detailed Implementation

[0041] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings; it should be understood that the specific embodiments given herein are only for illustration and explanation of the present invention and cannot be used to limit the present invention.

[0042] Referring to the attached drawings, the main construction process of the reverse construction method for the double-layer combined rotating bridge includes:

[0043] (1) On the construction site on the side parallel to the existing railway direction, first carry out the construction of bored piles, the foundation pit protection works of the bridge pier foundation, the bridge pile foundation and the lower abutment, the backfilling construction from the foundation pit to the top of the abutment, install the rotation system, pour the upper abutment of the main pier and construct the bridge pier cap beam, and at the same time construct the foundation of the side pier and the bridge pier and cap beam.

[0044] (2) Level the site, harden the support foundation and material storage area; remove all silt in the site in the early stage of construction and replace it with rubble, the bearing capacity of the foundation shall not be less than 200KPa, the steel truss storage area shall be hardened with 20cm thick C30 concrete as a whole; reinforce the crawler crane traveling foundation; the temporary support foundation of the steel truss shall be an 8.5m*8.5m convex C35 reinforced concrete enlarged foundation, the cast-in-place beam disc buckle full-span support foundation shall be a 25cm thick C30 concrete, the lower foundation bearing capacity shall not be less than 200KPa, and the foundation bearing capacity shall be tested by K30 plate load test;

[0045] (3) Temporary supports are set up for the steel truss nodes of the upper steel truss support. The main pier is divided into 6 rows of temporary supports in both directions, numbered 1, 2...6 in sequence, with 3 sets of temporary supports in each row; the temporary supports of nodes 1, 2, 3 and 5 are assembled by connecting 4 steel pipes. The temporary supports of nodes 4 and 6 are made of 2 steel pipe concrete temporary supports to consider the increase of reaction force during dismantling. A total of 24 sets of steel pipe temporary supports and 12 sets of steel pipe concrete temporary supports are arranged.

[0046] The top column of the temporary support of the steel pipe pier is sealed with welded steel plate. A sand bucket is set on the upper part of the column. The longitudinal beam is made of double-section steel. The upper crossbeam is reinforced with 5 sections of steel with double-section steel every other. The bottom of the crossbeam is adjusted with steel plate pads according to the height of the bottom of the beam. The upper and lower parts of the pier are firmly welded to the pre-embedded positioning steel plate.

[0047] The top column of the temporary support of the steel pipe concrete pier is sealed with welded steel plate. A sand bucket is set on the top of the column. The crossbeam is welded with steel plate. The 6th pier, which was last to be demolished, needs to be lowered by four 600t jacks. The upper structure of the steel pipe is a crossbeam. Three-section I-beams and thick pads are set on the top of the crossbeam.

[0048] During the installation of temporary supports, timely corrections should be made to control verticality deviation and column top offset.

[0049] (4) Temporary consolidation of the main pier: Temporary supports and temporary anchorages are set on the top of the main pier to bear the maximum vertical support reaction at the middle support point; the temporary supports are set on the pier and the thickness is 0.8m from the bottom of the beam to the top of the cap beam; each temporary support is reinforced with steel bars embedded in the top of the pier and the cast-in-place beam, and the material of the temporary supports is C60 concrete; after the main bridge is rotated, the temporary consolidation of the main pier can be removed only after the supports at both ends are installed, and the removal is carried out by wire saw cutting;

[0050] (5) Construction of hoisting and assembling of upper steel truss beams

[0051] The steel truss assembly and installation shall be carried out according to the following principles: from bottom to top, first the lower plane, then the elevation, to form a stable triangular structure as soon as possible, and then install the upper plane. Before assembly, the node plates, assembly plates, filler plates, and high-strength bolts shall be placed near each node.

[0052] The specific steps for assembling the steel truss are as follows:

[0053] 1) Pre-assembly of the lower chord: The lower chord is connected to the node plate, splicing plate and filler plate at the front end of the steel truss assembly with punch nails and a small number of bolts. The punch nails are driven in according to the main truss node assembly requirements, and a small number of bolts are left untightened so that the other members can be installed. The bolts are attached to the chord.

[0054] 2) Pre-assembly of main truss diagonal members and upper chord: The main truss diagonal members and upper chord are pre-assembled into a triangular truss on the horizontal position of the pre-assembly site. The front end of the steel truss beam is assembled with the node plate at the large node. The splicing plate and filler plate are connected with punch nails and a small number of bolts. The punch nails are driven in according to the main truss node assembly requirements. A small number of bolts are not tightened to facilitate the installation of other members. A small number of punch nails and bolts are used to fasten the intermediate small sections to the chord. The triangular truss is assembled and connected to the node plate of the lower chord using a 450T conveyor crane. The assembly is carried out from the middle of the line to both sides to form a stable triangular frame in space.

[0055] 3) Pre-assembly of the upper horizontal longitudinal bracing: The beam is equipped with an upper horizontal longitudinal bracing system, a cross-structure. The upper horizontal longitudinal bracing is installed simultaneously after the corresponding main truss diagonal members and upper chord members are installed. The bracing members are spliced ​​and connected to the flange node plates of the upper chord members. The bracing uses I-shaped cross-section members. First, the transverse members are assembled and connected to the upper chord members, and then the cross members are installed and connected to the upper chord members to quickly form a stable structure.

[0056] 4) Bridge deck pre-assembly: After the upper horizontal longitudinal bracing corresponding to the bridge deck is installed, the bridge deck is installed simultaneously. A crossbeam is set every 2.5m of the bridge deck. The upper flange of the crossbeam and the lower chord are bolted to the node plate. The web and the lower flange are connected with high-strength bolts. The connection sequence is to weld first and then bolt. Before welding, the punch pins are used for positioning.

[0057] 5) The specific installation steps are as follows: Install the entire lower horizontal bracing of the first section: The first 450T crawler crane will install the lower horizontal bracing between the main pier and node 1 on the side closest to the existing line section. Then, the second 450T crawler crane will arrive, and both crawler cranes will simultaneously install the lower horizontal bracing from the middle to both sides. The lower horizontal bracing is a temporary member made of HW300*300*10*15 steel and must be removed before the concrete section is poured. Install the lower chord, upper chord, and main truss diagonal members of the first section: First, install the upper chord and corresponding main truss diagonal members of the section between the main pier and node 1. Then, both crawler cranes will simultaneously install the remaining upper chord and main truss diagonal members from the middle to both sides.

[0058] Installation of the first horizontal and longitudinal bracing and bridge deck: After the main pier and the upper chord and main truss diagonal members of the No. 1 node section are installed, the corresponding horizontal and longitudinal bracing and bridge deck of the main pier are installed, and the components are installed from the middle to both sides.

[0059] Install the second section of the lower chord, upper chord, diagonal brace, upper horizontal longitudinal brace, and bridge deck: the installation sequence is the same, proceeding from the middle to both sides.

[0060] (6) Parallel railways are erected with cast-in-place supports, and all steel structures (including temporary members) are assembled and welded on the supports.

[0061] In specific projects, steel tie rod devices are evenly arranged on the lower chord of the upper steel truss structure, with the arrangement interval set to a horizontal spacing of 1.2-1.5 meters.

[0062] (7) The lower layer of concrete beams is poured and tensioned in sections from the middle to both sides. The pier beams at the main pier are temporarily fixed.

[0063] (8) Construct the lower outer side inspection passage railing; construct the upper and lower outer side anti-collision guardrails and anti-throw nets.

[0064] (9) Unload the support at multiple points and in stages to allow the cantilever structure to deflect naturally and completely. Note that the longitudinal overturning stability of the cantilever structure must be guaranteed during the unloading process.

[0065] In the specific implementation, the temporary supports at positions 1, 3, and 5 are removed first, followed by the temporary supports at positions 2 and 4; then, temporary steel supports are installed next to the main pier, ensuring that the temporary steel supports do not restrict the symmetrical downward deflection of the cantilever structure, and that the steel supports are tightly fitted to the bottom of the beam without gaps after the cantilever deflection is completed; the temporary steel support structure only provides vertical support to the main beam, and the horizontal force is borne by the tie rods in the support system; then, temporary support No. 6 and all other cast-in-place supports are removed.

[0066] (10) Rotation construction: Rotate the rotating beam segment counterclockwise by 81.1° to the completed bridge position, lock it, and construct the post-cast section of the rotation system;

[0067] After the main beam is rotated into place and locked, jacks are placed on the top surface of the lower cap beam of the side pier to lift the beam ends on each side. The lifting force and the amount of lifting displacement are controlled simultaneously, and the error must be controlled within 5%. The side pier support is installed, the lifting jacks are removed, and the system conversion is completed.

[0068] (11) Remove the temporary auxiliary facilities for rotation, release the temporary pier and beam fixing measures, and install the main pier support.

[0069] (12) In conjunction with the construction progress of adjacent sections, construct the upper pier columns and cap beams of the side piers, and the ancillary works of the entire bridge, and finally complete the acceptance and open the bridge to traffic.

Claims

1. A method for reverse construction of a continuous steel truss web-plate truss double-layer composite rotating bridge, characterized in that: The reverse construction process of the double-layer combined rotating bridge includes the following steps: (1) On the construction site on the side parallel to the existing railway, first carry out the construction of bored piles, the foundation pit protection works of the bridge pier foundation, the bridge pile foundation and lower abutment, the backfilling construction from the foundation pit to the top of the abutment, install the rotation system, pour the upper abutment of the main pier and construct the bridge pier cap beam, and at the same time construct the foundation of the side pier, the lower pier column and the lower cap beam. (2) Level the construction site, harden the scaffold foundation and material storage area; harden the site as a whole in the early stage of construction; reinforce the crawler crane traveling foundation; construct the temporary support for steel truss beams and the full-span scaffold foundation for cast-in-place beams; (3) Temporary supports are set up for the steel truss nodes corresponding to the steel truss supports. There are 6 rows of temporary supports on both sides of the main pier, with 3 sets of temporary supports in each row. The temporary supports for nodes 1, 2, 3, and 5 are assembled by connecting 4 steel pipes. The temporary supports for nodes 4 and 6 are made of 2 steel pipe concrete supports. A total of 24 sets of steel pipe temporary supports and 12 sets of steel pipe concrete temporary supports are arranged. The top column of the steel pipe concrete temporary support is sealed with welded steel plate. A sand bucket is set on the top of the column. The crossbeam is made of welded steel plate. The last temporary support for node 6 needs to be dismantled by 4 jacks. The upper structure of temporary support for node 6 is a crossbeam. Three 56 I-beams and thick pads are set on the top of the crossbeam. (4) The specific hoisting sequence and steps of the upper steel truss girder of the double-layer combined rotating bridge are as follows: 1) Install the first section of the lower horizontal bracing: The first crawler crane to arrive will install the lower horizontal bracing at the location of the main pier and the temporary support pier at node 1 closest to the existing line section. Then, the second crawler crane will arrive, and both crawler cranes will simultaneously install the lower horizontal bracing from the middle to both sides. The lower horizontal bracing is a temporary member made of steel members and must be removed before the concrete section is poured. 2) Install the first section of the upper chord and main truss diagonal members: First, install the upper chord and the corresponding main truss diagonal members at the main pier and the temporary support pier at node 1. Then, both crawler cranes will simultaneously install the remaining upper chord and main truss diagonal members from the middle to both sides. 3) Install the first upper horizontal and longitudinal bracing and bridge deck: After the upper chord and main truss diagonal bracing between the main pier and the temporary support pier at node 1 are installed, start installing the corresponding upper horizontal and longitudinal bracing and the corresponding bridge deck, and install the components from the middle to both sides. 4) Install the second section of lower chord, upper chord, diagonal brace, upper horizontal longitudinal brace, and bridge deck: The installation sequence is also from the middle to both sides. (5) Parallel railways are erected with cast-in-place beam disc-lock full-span scaffolding. All steel structures are assembled and welded on the cast-in-place beam disc-lock full-span scaffolding. The lower concrete beams are poured and tensioned in sections from the middle to both sides. (6) Temporary consolidation of the main pier: Temporary supports and temporary anchorages are set on the top of the main pier. The temporary supports are set on the pier and the thickness is 0.8m from the bottom of the beam to the top of the cap beam. Each temporary support has steel bars embedded in the top of the pier and the cast-in-place beam. The material of the temporary supports is C60 concrete. After the main bridge is rotated, the temporary consolidation of the main pier can be removed after the supports at both ends are installed. The removal is done by cutting with a wire saw. (7) Construction of the lower outer maintenance passage railing; construction of the upper and lower outer anti-collision guardrails and anti-throw nets; (8) Unload the cast-in-place beam tray-type full-span scaffolding at multiple points and in stages; (9) Install temporary steel supports next to the main pier; (10) Remove all cast-in-place beam scaffolding; (11) Rotation construction: Rotate the rotating beam segment to the completed bridge position and lock it; and construct the post-cast section of the rotation system; (12) After the body is rotated into place and locked, jacks are placed on the top surface of the lower layer cap beam of the side pier to lift the beam ends on each side of the main beam. The lifting force and the lifting displacement are controlled simultaneously. (13) Install the side pier supports, remove the lifting jacks, and complete the system conversion; (14) Remove the temporary auxiliary facilities for rotation, release the temporary fixing measures for the piers and beams, and install the main pier supports; (15) In conjunction with the construction progress of adjacent sections, construct the upper piers and upper cap beams of the side piers, and the ancillary works of the entire bridge, and finally complete the acceptance and open the road to traffic.

2. The method for reverse construction of a continuous steel truss web-plate truss double-layer composite rotating bridge according to claim 1, characterized in that: Before pouring the lower concrete beam, after erecting the full-span scaffolding for the cast-in-place beam, a steel tie rod device is used to connect the formwork of the full-span scaffolding for the cast-in-place beam to the upper steel truss structure.

3. The method for reverse construction of a continuous steel truss web-plate truss double-layer composite rotating bridge according to claim 2, characterized in that: The steel tie rod devices are evenly arranged on the lower chord of the upper steel truss structure, with a horizontal spacing of 1.2-1.5 meters between them.

4. The method for reverse construction of a continuous steel truss web-plate truss double-layer composite rotating bridge according to claim 1, characterized in that: During the dismantling of temporary supports, the temporary supports at positions 1, 3, and 5 were dismantled first, followed by the temporary supports at positions 2 and 4; then temporary steel supports were installed next to the main pier; and finally, temporary support No. 6 was dismantled.

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