Construction method for erecting whole-section steel truss girder of large-span rotary cable ground anchor type suspension bridge

Abstract

The invention discloses a construction method for erecting a whole-section steel truss girder of a large-span rotary cable ground anchor type suspension bridge, and belongs to the technical field of bridge construction.A tower of a cable crane is arranged on one side of a north anchor, a temporary cable saddle of the cable crane is arranged on an upper cross beam of a main tower, the cable crane is installed through an existing catwalk, and the whole-section steel truss girder of the large-span rotary cable ground anchor type suspension bridge is erected. The span combination of the cable cranes is 49m + 516m + 177.9 m, the designed hoisting weight is 145T, each cable crane is provided with two load-carrying trolleys, two 25t friction type traction winches, four 15t single-barrel hoisting winches and two 25t winches, the temporary tower is arranged on the north anchor, the height of the temporary tower is 32.27 m, the temporary tower is welded with the base of the north anchor, and the temporary tower is connected with the base of the north anchor. A tower column of the main tower is composed of stand columns, a transverse connecting system and an inclined connecting system, the stand columns are steel pipes of phi 630 * 20 mm, and the stand columns are connected through bolts. In this way, the stability of the rotary cable and the accuracy of the line shape of the steel truss girder in the construction process of the whole section of the steel truss girder can be guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of bridge construction, in particular to a method for erecting a whole-segment steel truss of a large-span rotary cable anchored suspension bridge. Background Art

[0002] The erection of the entire section steel truss of a large-span revolving cable ground-anchored suspension bridge is a complex bridge erection construction. The main cable is the main load-bearing component of the ground-anchored suspension bridge. The current construction method of the revolving cable ground-anchored suspension bridge is to anchor the main cable saddle and the revolving cable saddle to adapt to the rotation of the main cable and bear the horizontal centripetal pressure of the main cable. The anchored main cable saddle adopts a horizontal saddle groove structure to adapt to the lateral centripetal force of the main cable. The overall structure adopts a horizontally placed structure. The turning of the revolving cable at the anchorage is controlled by 1 main cable saddle and 2 revolving cable saddles. The main cable saddle is fixed and the revolving cable saddle can slide longitudinally. The revolving cable saddle transmits the main cable load change to the main cable saddle through longitudinal displacement, so that the main cable force can be better transmitted. However, when the entire section steel truss is hoisted, the transmission of cable force will have a certain impact on the erection of the steel truss.

[0003] A Chinese patent with publication number CN107190627B proposes a partially ground-anchored suspension bridge and a construction method thereof, comprising two side piers, a main beam erected on the two side piers, a main tower located between the two side piers, a main cable erected on the main tower and anchored at both ends of the main beam, a hanger for lifting the main beam, a ground anchor arranged outside the two ends of the main beam, and an anchor cable for connecting the ground anchor and the end of the main beam, both ends of the main beam are provided with a main cable anchoring position and an anchor cable anchoring position, the main cable is erected on the main tower and anchored at the main cable anchoring positions at both ends of the main beam, the ground anchor is connected to the anchor cable anchoring positions at both ends of the main beam through an anchor cable, one end of the anchor cable is anchored on the ground anchor as an adjustable tensioning end, and the other end is anchored at the end of the main beam as a fixed end, the cable force of the anchor cable is tensioned by a jack, a pressure sensor under the anchor or a cable acceleration sensor is arranged for observation and recording, and the cable is adjusted by tensioning with a jack.

[0004] However, the technical solution of this patent has the following problems:

[0005] This patent discloses that when hoisting a whole section of steel trusses, the transmission of cable force will have a certain impact on the erection of the steel trusses.

[0006] Based on this, the present invention designs a construction method for erecting a whole-segment steel truss of a large-span rotary cable ground-anchored suspension bridge to solve the above-mentioned problem. Summary of the invention

[0007] In view of the above-mentioned shortcomings of the prior art, the present invention provides a method for erecting a whole-segment steel truss of a large-span rotary cable ground-anchored suspension bridge.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0009] A method for erecting a whole-segment steel truss of a large-span rotary cable anchored suspension bridge comprises the following steps:

[0010] Step 1: Set up the tower of the cable crane on one side of the north anchorage, set up a temporary saddle for the cable crane on the crossbeam on the main tower, and use the existing catwalk to install the cable crane. The span combination of the cable crane is 49m+516m+177.9m, with a designed lifting capacity of 145T. Each set of cable crane is equipped with two load trolleys, and each set of cable crane is equipped with 2 25t friction traction winches, 4 15t single-drum hoisting winches and 2 25t winches (temporary traction winches);

[0011] The temporary tower frame is set on the north anchorage with a height of 32.27m. The temporary tower frame is welded to the foundation of the north anchorage. The tower column of the main tower is composed of columns, transverse and oblique connection systems. The columns are φ630×20mm steel pipes. The columns are connected by bolts, and the other transverse and oblique connection systems are connected by welding.

[0012] Four sets of temporary saddles are arranged on the upper beam of the main tower and above the crossbeam of the temporary tower frame at the north anchorage, with the center distance between adjacent temporary saddles being 17.1m;

[0013] The main cables are composed of 11 φ60 (6×37S+IWR) steel wire ropes. The main cables are arranged in two groups, upstream and downstream. The center distance between the upstream and downstream main cables is 17.1m. The main cables are anchored on the north and south anchors on both banks. The main cable adjustment system and cable laying site are set up on the south bank.

[0014] The traction rope adopts 2×1Φ38 (6×37S+FC) steel rope, the hoisting rope adopts 2×2Φ36 (6×37S+FC) steel rope, the traction system adopts a circular arrangement, the traction system and the hoisting winch are arranged on the south bank, and the north bank is only used as the traction rope steering and hoisting rope anchoring position;

[0015] Step 2: Use the existing construction platform in the middle of the main tower to set up auxiliary supports, and assemble the 34th and 33rd steel trusses on the side span as the platform for rotating the entire section steel trusses and lifting the beams with cables;

[0016] The columns of the auxiliary support are made of spiral welded pipes of φ800*12mm and φ630*12mm. The columns of the auxiliary support are connected by steel pipes of φ219*6mm. According to the cross girder nodes of the steel beam, a total of 4 columns of auxiliary support are set. Five columns of auxiliary support are set in each column on the upstream side. Since the side edge line of the downstream cliff is inward, 4 columns of auxiliary support are set in each column (no columns of auxiliary support are set at the front end);

[0017] Step 3: Assemble the whole segment steel truss at the on-site steel beam assembly yard (the whole segment steel truss has one end open and one end closed, with two sets of bridge decks. One set of bridge decks is installed during assembly, and the remaining set of bridge decks is installed after the whole bridge is closed). Complete the welds and high bolts that can be constructed, and complete the painting. After the whole segment steel truss is assembled, it is stored on the roadbed;

[0018] The large-segment steel truss assembling adopts the "3+1" mode matching to assemble the large-segment steel truss in the steel beam assembly yard. The assembled large-segment steel truss is stored on the roadbed and supported by a tire frame with a height of 1.5m. The tire frame adopts Φ325×10mm steel pipe as the tire frame column. The tire frame column foundation adopts 2000×2000×350mm reinforced concrete independent foundation. The tire frame column bottom plate is welded to the foundation embedded parts;

[0019] When assembling large-segment steel trusses, the assembly is carried out in the order of assembling beam segments 1-32. First, the starting round of steel beams is assembled, which are beam segments 1-4. After the assembly is completed, beam segments 1-3 are transported out of the assembly yard for storage. Beam segment 4 is used as the mother segment of the next round and is transported to the position of beam segment 1. The subsequent beam segments are matched and assembled, and the overall assembly test assembly of beam segments 1-32 is completed at the assembly yard;

[0020] Step 4: Use a self-propelled modular flatbed truck to transport the No. 1 whole segment steel truss to the No. 34 and No. 33 steel trusses on the side span, and use a cable crane to hoist it;

[0021] Two self-propelled modular flatbed trucks were used to transport the whole segment steel truss No. 1 to the lifting platform of the No. 34 and No. 33 steel trusses, and rotated 90 degrees to prepare for lifting. The whole segment steel truss was hoisted at 4 points, with the hoisting points set at the junction of the upper crossbeam and the vertical web. The lifting lugs were welded to the bridge deck, and the welds were partial penetration fillet welds. The horizontal spacing of the hoisting points was 17.1 meters, and the vertical spacing was 7.5 meters.

[0022] The cable crane hoisted the No. 1 segment from the south working platform. During the hoisting process, the entire segment steel truss was transported under the main cable. After being hoisted to the installation position 1, the entire segment steel truss was first connected to the sling, and the other end fell on the support. After the connection was completed, the steel beam and the anchor were temporarily longitudinally limited. The weight of the No. 1 segment was 483t. Due to the transportation conditions of the T-beam, the upper crossbeam and web member (73.6t), 2 sets of bridge decks (107.8t), and the lower crossbeam and part of the lower flat joint (41.39t) at the end were not installed. The lifting weight after weight reduction was 265t. After the entire segment was hoisted, the remaining rods and bridge decks were installed.

[0023] Step 5: The large-segment steel truss beams are erected in the order of beam segments 1 to 32, that is, from the anchorage on the revolving cable side to the main tower side;

[0024] During the erection of the steel beam, the cable crane hoists the next section of the standard steel beam on the working platform. After the hoisting is completed, it is transported to the installation position under the main cable. The cable crane hoisting cable is connected to the steel beam. The erected beam section steel beam and the installed beam section are hinged with a pin through a temporary hinge device. When hoisting and aligning, a code plate is welded next to the temporary hinge of the two main trusses of the beam section to be erected for auxiliary alignment. The temporary hinge device is located at the end of the upper chord of the steel beam and is used for temporary hinge alignment when the steel beam is erected. Yin and Yang buckles are respectively set on the upper chord where the two sections of the steel beam are butted, and the pin is used for perforation and fixation. The hinge device is welded to the top plate of the upper chord;

[0025] Step 6: When the large-segment steel trusses are erected to a certain section, they are rigidly connected in pairs. After the hoisting of the whole segment steel truss No. 26 is completed, the steel hinge conversion of all steel trusses No. 1-26 is completed. Subsequently, the hoisting of the beam sections No. 27-32 is completed one by one and then rigidly connected one by one;

[0026] Step 7: Hoist the No. 32 closure section, and complete the closure of the side span by pushing and moving vertically through the three-dimensional jack;

[0027] The length of the main bridge joint section (beam section No. 32) is 11.2m. After the joint section is hoisted, it is transported to the installation position under the main cable. The steel beam of the joint section is fixed to the installed beam section No. 31 with punch nails and installation bolts. The slings of beam sections No. 33 and 34 are connected to the steel beam. The vertical and horizontal spacing and rotation angles of steel beams No. 33-34 and No. 32 are adjusted by the three-dimensional jacks arranged on the columns of the auxiliary support. The steel beam of the joint section and beam section No. 33 are temporarily hinged. The two pairs of interfaces of the joint section are just connected, and the construction of the joint section is completed;

[0028] Step 8: Complete the erection of the steel beams of the entire bridge;

[0029] According to the monitoring instructions, after the steel beams are rigidly connected, the bridge decks at the connection are installed; a bridge deck lifting hanger is set on the cable crane. The hanger structure is welded from HW300×300×10 / 15mmH-shaped steel and square steel pipes. The hanger has a total of 12 lifting points, 4 lifting points for each bridge deck. At the same time, three groups of bridge decks are lifted as a whole. After lifting to the installation position, the bridge decks on both sides are first connected to the steel beams, and finally the middle bridge deck is installed.

[0030] Compared with the prior art, the invention has the following beneficial effects: the invention sets a cable crane tower beside the north anchor, sets a temporary cable saddle on the main tower crossbeam, uses the existing catwalk for installation, sets an auxiliary bracket on the existing platform in the main tower span, and assembles the side span No. 34 and No. 33 steel trusses as a beam lifting and rotating platform. Four rows of auxiliary bracket columns are set according to the steel beam nodes, with different numbers of upstream and downstream. The spiral welded pipe and connection system are used to assemble the entire segment steel truss on site, with one end open and the other end closed. First, a set of bridge panels are installed, and then the bridge deck is assembled. The remaining steel trusses after the dragon are matched and assembled into large sections, stored on the roadbed, supported by a frame, and transported to the lifting platform by a self-propelled flatbed vehicle. They are rotated for lifting and lifted with reduced weight according to transportation conditions. They are anchored from the slewing cable side to the main tower side in the order of 1-32, and lifted and hinged by a cable crane. After a certain number of steel truss sections are erected, they are rigidly connected in pairs, and then the bridge is closed and the bridge deck is installed. This can ensure the stability of the slewing cable and the accuracy of the steel truss line shape during the construction of the entire section of the steel truss. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 This is a schematic diagram of the main cable installation and temporary support construction of the present invention;

[0033] Figure 2 This is a schematic diagram of the lifting of the steel truss segment of the present invention;

[0034] Figure 3 Schematic diagram of the steel truss segment erection of the present invention Figure 1 ;

[0035] Figure 4 Schematic diagram of the steel truss segment erection of the present invention Figure 2 ;

[0036] Figure 5 Schematic diagram of the steel truss segment erection of the present invention Figure 3 ;

[0037] Figure 6 The present invention is to close the bridge.

[0038] The numbers in the figure represent:

[0039] 1. North anchor; 2. Hoisting rope; 3. Main tower; 4. Temporary tower; 5. Temporary saddle; 6. Main rope; 7. South anchor; 8. Towing rope; 9. South bank; 10. North bank; 11. Auxiliary support. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] The present invention will be further described below in conjunction with the embodiments.

[0042] Embodiment 1: In some embodiments, please refer to Figure 1-Figure 6 A method for erecting a whole-segment steel truss girder of a large-span rotary cable anchored suspension bridge comprises the following steps:

[0043] Step 1: Please refer to the attached Figure 1 , a cable crane tower is set on one side of the north anchor 1, a temporary saddle 5 of the cable crane is set on the upper beam of the main tower 3, and the cable crane is installed using the existing catwalk. The span combination of the cable crane is 49m+516m+177.9m, with a designed lifting capacity of 145T. Each cable crane is equipped with two load trolleys, and each cable crane is equipped with two 25t friction traction winches, four 15t single-drum hoisting winches and two 25t winches (temporary traction winches);

[0044] Temporary tower 4 is set on north anchor 1, with a height of 32.27m. Temporary tower 4 is welded to the foundation of north anchor 1. The tower column of main tower 3 is composed of vertical column, transverse and diagonal connection system. The vertical column is φ630×20mm steel pipe, and the vertical column is connected by bolts. The other transverse and diagonal connection systems are connected by welding.

[0045] There are 4 sets of temporary saddles 5, which are arranged on the upper beam of the main tower 3 and above the beam of the temporary tower 4 of the north anchor 1, and the center distance between adjacent temporary saddles 5 is 17.1m;

[0046] The main cable 6 is composed of 11 φ60 (6×37S+IWR) steel wire ropes. The main cable 6 is arranged in two groups, upstream and downstream. The center distance between the upstream and downstream main cables 6 is 17.1m. The main cables 6 are anchored on the north anchor 1 and the south anchor 7 on both sides of the river. The main cable 6 adjustment system and cable laying site are set on the south bank 9.

[0047] The traction rope 8 adopts 2×1Φ38 (6×37S+FC) steel rope, the hoisting rope 2 adopts 2×2Φ36 (6×37S+FC) steel rope, the traction system adopts a circular arrangement, the traction system and the hoisting winch are arranged on the south bank 9, and the north bank 10 is only used as the turning position of the traction rope 8 and the anchoring position of the hoisting rope 2;

[0048] Step 2: Please refer to the attached Figure 2 , using the existing construction platform in the middle of the main tower 3 span to set up auxiliary bracket 11, and assembling the 34th and 33rd steel trusses on the side span as the platform for rotating the entire segment steel trusses and lifting the beams with cables;

[0049] The columns of the auxiliary support 11 are made of spiral welded pipes of φ800*12mm and φ630*12mm. The columns of the auxiliary support 11 are connected by steel pipes of φ219*6mm. According to the cross girder nodes of the steel beam, a total of 4 columns of the auxiliary support 11 are arranged. Five columns of the auxiliary support 11 are arranged in each column on the upstream side. Since the side edge line of the downstream cliff is inward, four columns of the auxiliary support 11 are arranged in each column (no column of the auxiliary support 11 is arranged at the front end);

[0050] Step 3: Assemble the whole segment steel truss at the on-site steel beam assembly yard (the whole segment steel truss has one end open and one end closed, with two sets of bridge decks. One set of bridge decks is installed during assembly, and the remaining set of bridge decks is installed after the whole bridge is closed). Complete the welds and high bolts that can be constructed, and complete the painting. After the whole segment steel truss is assembled, it is stored on the roadbed;

[0051] The assembly of large-segment steel trusses adopts the "3+1" matching mode. The large-segment assembly is carried out in the steel beam assembly yard. The "3+1" mode: assemble 4 whole-segment steel trusses in the first round, and use the last whole-segment steel truss of the previous round as the mother section in the subsequent rounds of assembly. The subsequent 3 whole-segment steel trusses are matched and assembled to ensure the matching accuracy between beam sections and the assembly accuracy of whole-segment steel trusses. The assembled large-segment steel trusses are stored on the roadbed and supported by a tire frame with a height of 1.5m. The tire frame uses Φ325×10mm steel pipes as tire frame columns. The tire frame column foundation uses a 2000×2000×350mm reinforced concrete independent foundation. The tire frame column bottom plate is welded to the foundation embedded parts;

[0052] When assembling large-segment steel trusses, they are assembled in the order of assembling beam segments 1-32. First, the whole segment steel trusses of the starting round are assembled. The whole segment steel trusses of the starting round are beam segments 1-4. After the assembly is completed, beam segments 1-3 are transported out of the assembly yard for storage. Beam segment 4 is used as the mother segment of the next round and is transported to the position of beam segment 1. The subsequent whole segment steel trusses are matched and assembled, and the overall assembly test assembly of beam segments 1-32 is completed at the assembly yard;

[0053] Step 4: Please refer to the attached Figure 3 , use a self-propelled modular flatbed truck to transport the No. 1 large segment steel truss to the No. 34 and No. 33 steel trusses on the side span, and use a cable crane to hoist it;

[0054] Two self-propelled modular flatbed trucks were used to transport the No. 1 large-segment steel truss to the lifting platforms of No. 34 and No. 33 steel trusses in parallel and in a coordinated manner. The large-segment steel truss was rotated 90 degrees to prepare for lifting. The large-segment steel truss was hoisted at four points. The hoisting points were set at the junction of the upper crossbeam and the vertical web. The lifting lugs were welded to the bridge deck. The welds were partial penetration fillet welds. The horizontal spacing of the hoisting points was 17.1 meters, and the vertical spacing was 7.5 meters.

[0055] The cable crane hoists the No. 1 segment from the south working platform. During the hoisting process, the large segment steel truss is transported under the main cable. After being hoisted to the installation position 1, the large segment steel truss is first connected to the sling, and the other end falls on the support. After the connection is completed, the large segment steel truss is temporarily longitudinally limited to the north anchor 1. The weight of the No. 1 segment is 483t. Due to the transportation conditions of the T-beam, the upper crossbeam and web member (73.6t), 2 sets of bridge decks (107.8t), the lower crossbeam and part of the lower flat joint (41.39t) at the end are not installed. The lifting weight after weight reduction is 265t. After the large segment steel truss is hoisted, the remaining rods and bridge decks are installed.

[0056] Step 5: Please refer to the attached Figure 4 and attached Figure 5 The erection sequence of the large-segment steel trusses is from beam sections 1 to 32, that is, from the south anchorage 7 on the turnaround cable side to the main tower 3 side;

[0057] During the erection of the large-segment steel truss, the cable crane hoists the next section of the standard large-segment steel truss on the working platform. After the hoisting is completed, it is transported to the installation position under the main cable. The cable crane hoisting cable is connected to the large-segment steel truss. The erected large-segment steel truss is hinged with the installed large-segment steel truss by a temporary hinge device using a pin shaft. During the hoisting alignment, a code plate is welded next to the temporary hinge of the two main trusses of the large-segment steel truss to be erected for auxiliary alignment. The temporary hinge device is located at the end of the upper chord of the large-segment steel truss, which is used for temporary hinge alignment when the large-segment steel truss is erected. Yin and Yang buckles are respectively set on the upper chords where the two large-segment steel trusses are butt-jointed, and the pin shaft is used for perforation and fixation. The hinge device is welded to the top plate of the upper chord.

[0058] Step 6: When the large-segment steel trusses are erected to a certain section, they are rigidly connected in pairs. After the No. 26 large-segment steel truss is hoisted, the steel hinge conversion of all the large-segment steel trusses No. 1-26 is completed. Subsequently, the No. 27-32 large-segment steel trusses are hoisted and rigidly connected one section at a time.

[0059] Step 7: Please refer to the attached Figure 6 , hoisting the No. 32 closure section, the side span was completed by pushing and moving vertically through the three-dimensional jack;

[0060] The length of the main bridge joint section (beam section No. 32) is 11.2m. After the joint section is hoisted, it is transported to the installation position under the main cable. The large segment steel truss of the joint section is fixed to the installed large segment steel truss No. 31 by using nails and installation bolts. The slings of the large segment steel trusses No. 33 and 34 are connected to the large segment steel trusses of the joint section. The three-dimensional jacks arranged on the columns of the auxiliary support 11 are used to adjust the longitudinal and transverse spacing and rotation angles of the large segment steel trusses No. 33-34 and the large segment steel trusses No. 32, and the large segment steel trusses of the joint section are temporarily hinged with the large segment steel trusses No. 33. The two pairs of interfaces of the joint section are just connected, and the construction of the joint section is completed;

[0061] Step 8: Hoist the remaining bridge decks and complete the erection of the steel beams of the entire bridge;

[0062] According to the monitoring instructions, after the large-section steel trusses are rigidly connected, the bridge decks at the connections are installed; a bridge deck hoisting hanger is set on the cable crane, and the hanger structure is welded from HW300×300×10 / 15mmH-shaped steel and square steel pipes. The hanger has a total of 12 lifting points, 4 lifting points for each bridge deck, and three groups of bridge decks are hoisted as a whole at the same time. After hoisting to the installation position, the bridge decks on both sides are first connected to the large-section steel trusses, and finally the middle bridge deck is installed.

[0063] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for erecting a whole-segment steel truss of a large-span rotary cable anchored suspension bridge, characterized in that: The following steps are involved: Step 1: Main cable installation; A cable crane tower is set on one side of the north anchor (1), a temporary cable saddle (5) of the cable crane is set on the upper crossbeam of the main tower (3), and the cable crane is installed using the existing catwalk. Two load trolleys are set for each cable crane, and 8 winches are arranged for each cable crane; The temporary tower frame (4) is arranged on the north anchor (1), and the temporary tower frame (4) is welded to the foundation of the north anchor (1). The tower column of the main tower (3) is composed of a column, a transverse connection system and an oblique connection system. The column is connected by bolts, and the other transverse connection systems and the oblique connection systems are connected by welding. The temporary saddles (5) are provided in four sets, which are arranged respectively on the upper cross beam of the main tower (3) and above the cross beam of the temporary tower frame (4) of the north anchor (1); The main cables (6) are arranged in two groups, upstream and downstream. The main cables (6) are anchored on the north anchor (1) and the south anchor (7) on both banks. A main cable (6) adjustment system and a cable-laying site are arranged on the south bank (9). The traction system is arranged in a circular manner, with the traction system and the hoisting winch arranged on the south bank (9), and the north bank (10) serving only as a turning point for the traction rope (8) and an anchoring position for the hoisting rope (2); Step 2: Temporary support construction; An auxiliary support (11) is set up using the existing construction platform at the mid-span position of the main tower (3), and the 34th and 33rd steel trusses on the side span are assembled as a platform for rotating the entire segment steel truss and lifting the truss with cables; A total of 4 columns of auxiliary supports (11) are arranged according to the steel beam cross truss nodes, 5 columns of auxiliary supports (11) are arranged in each column on the upstream side, and 4 columns of auxiliary supports (11) are arranged in each column because the side edge line of the downstream cliff is inwardly drawn; Step 3: Assembling steel truss segments; Step 4: Lifting of steel truss segments; Step 5: Erection of steel truss segments; Step 6: Butt joint of steel truss segments; Step 7: Bridge closure; Step 8: Bridge deck installation.

2. The method for erecting a whole-segment steel truss of a large-span rotary cable anchored suspension bridge according to claim 1 is characterized in that: Step one also includes: the span combination of the cable crane is 49m+516m+177.9m, the designed lifting capacity is 145T, each cable crane is equipped with two load trolleys, and each cable crane is equipped with 2 25t friction traction winches, 4 15t single-drum lifting winches and 2 25t winches.

3. The method for erecting a whole-segment steel truss of a large-span rotary cable anchored suspension bridge according to claim 2 is characterized in that: Step 1 also includes: the temporary tower (4) has a height of 32.27m, and the columns are φ630×20mm steel pipes; The center distance between adjacent temporary saddles (5) is 17.1m; The main cable (6) is composed of 11 φ60 (6×37S+IWR) steel wire ropes, and the center distance between the upstream and downstream main cables (6) is 17.1m; The traction rope (8) adopts 2×1Φ38 (6×37S+FC) steel rope, and the lifting rope (2) adopts 2×2Φ36 (6×37S+FC) steel rope.

4. The method for erecting a whole-segment steel truss of a large-span rotary cable anchored suspension bridge according to claim 3 is characterized in that: Step 2 also includes: the columns of the auxiliary support (11) are made of spiral welded pipes of φ800*12mm and φ630*12mm, and the columns of the auxiliary support (11) are connected by steel pipes of φ219*6mm.

5. The method for erecting a whole-segment steel truss of a large-span rotary cable anchored suspension bridge according to claim 4 is characterized in that: Step three also includes: assembling the entire segment steel truss beam at the on-site steel beam assembly site (the entire segment steel truss beam is open at one end and closed at the other end, with two sets of bridge decks in total, one set of bridge decks is installed during assembly, and the remaining set of bridge decks is installed after the entire bridge is closed), completing the welds and high bolts that can be constructed, and completing the painting. After the entire segment steel truss beam is assembled, it is stored on the roadbed; The large-segment steel truss assembling adopts the "3+1" mode matching to assemble the large-segment steel truss in the steel beam assembly yard. The assembled large-segment steel truss is stored on the roadbed and supported by a tire frame with a height of 1.5m. The tire frame uses Φ325×10mm steel pipes as tire frame columns. The tire frame column foundation adopts a 2000×2000×350mm reinforced concrete independent foundation. The tire frame column bottom plate is welded to the foundation embedded parts; When assembling large-segment steel trusses, they are assembled in the order of beam sections 1-32. First, the entire segment steel trusses in the starting round are assembled. The entire segment steel trusses in the starting round are beam sections 1-4. After the assembly is completed, beam sections 1-3 are transported out of the assembly yard for storage. Beam section 4 is used as the mother section for the next round and is transported to the position of beam section 1. The subsequent entire segment steel trusses are matched and assembled, and the overall assembly trial assembly of beam sections 1-32 is completed at the assembly yard.

6. The method for erecting a whole-segment steel truss of a large-span rotary cable anchored suspension bridge according to claim 5 is characterized in that: Step 4 also includes: using a self-propelled modular flatbed vehicle to transport the No. 1 large segment steel truss to the No. 34 and No. 33 steel trusses on the side span, and using a cable crane to hoist it; Two self-propelled modular flatbed trucks were used to transport the No. 1 large-segment steel truss to the lifting platforms of No. 34 and No. 33 steel trusses in parallel and in a coordinated manner. The large-segment steel truss was rotated 90 degrees to prepare for lifting. The large-segment steel truss was hoisted at four points. The hoisting points were set at the junction of the upper crossbeam and the vertical web. The lifting lugs were welded to the bridge deck. The welds were partial penetration fillet welds. The horizontal spacing of the hoisting points was 17.1 meters, and the vertical spacing was 7.5 meters. The cable crane hoisted the No. 1 segment from the south working platform. During the hoisting process, the large segment steel truss was transported under the main cable. After being hoisted to the installation position 1, the large segment steel truss was first connected to the sling, and the other end fell on the support. After the connection was completed, the large segment steel truss was temporarily longitudinally limited to the north anchor (1). The weight of the No. 1 segment was 483t. Due to the transportation conditions of the T-beam, the upper crossbeam and web member (73.6t), two sets of bridge decks (107.8t), the lower crossbeam and part of the lower flat joint (41.39t) at the end were not installed. The lifting weight after weight reduction was 265t. After the large segment steel truss was hoisted, the remaining rods and bridge decks were installed.

7. The method for erecting a whole-segment steel truss of a large-span rotary cable anchored suspension bridge according to claim 6 is characterized in that: Step five also includes: erecting the large segment steel trusses in the order of No. 1 to No. 32 beam segments, that is, erecting from the south anchor (7) on the turnaround cable side to the main tower (3) side; During the erection of large-section steel trusses, the cable crane hoists the next section of standard large-section steel trusses on the working platform. After the hoisting is completed, it is transported to the installation position under the main cable. The cable crane's hoisting rope is connected to the large-section steel trusses. The erected large-section steel trusses are hinged to the installed large-section steel trusses through a temporary hinged device using pins. When hoisting and aligning, a code plate is welded next to the temporary hinge of the two main trusses of the large-section steel trusses to be erected for auxiliary alignment. The temporary hinged device is located at the end of the upper chord of the large-section steel trusses, and is used for temporary hinged alignment when the large-section steel trusses are erected. Yin and Yang buckles are respectively set on the upper chords where the two large-section steel trusses are connected, and pins are used for perforation and fixation. The hinged device is welded to the top plate of the upper chord.

8. The method for erecting a whole-segment steel truss of a large-span rotary cable anchored suspension bridge according to claim 7 is characterized in that: Step six also includes: when the large-section steel trusses are erected to a certain section, the large-section steel trusses are rigidly connected in pairs. After the lifting of the large-section steel truss No. 26 is completed, the steel hinge conversion of all the large-section steel trusses No. 1-26 is completed. Subsequently, the large-section steel trusses No. 27-32 are hoisted and rigidly connected one section at a time.

9. The method for erecting a whole-segment steel truss of a large-span rotary cable ground-anchored suspension bridge according to claim 8, characterized in that: Step seven also includes: hoisting the No. 32 closure section, and completing the closure of the side span by pushing and moving the side span through a three-dimensional jack; The length of the joint section of the main bridge (beam section No. 32) is 11.2m. After the joint section is hoisted, it is transported to the installation position under the main cable. The large segment steel truss of the joint section is fixed to the installed large segment steel truss No. 31 by using nails and installation bolts. The slings of the large segment steel truss No. 33 and No. 34 are connected to the large segment steel truss of the joint section. The longitudinal and transverse spacing and rotation angle of the large segment steel truss No. 33-34 and the large segment steel truss No. 32 are adjusted by using the three-dimensional jacks arranged on the columns of the auxiliary support (11). The large segment steel truss of the joint section and the large segment steel truss No. 33 are temporarily hinged. The two pairs of interfaces of the joint section are just connected, and the construction of the joint section is completed.

10. The method for erecting a whole-segment steel truss of a large-span rotary cable anchored suspension bridge according to claim 9, characterized in that: Step eight also includes: hoisting the remaining bridge decks to complete the erection of the steel beams of the entire bridge; According to the monitoring instructions, after the large-section steel trusses are rigidly connected, the bridge decks at the connections are installed; a bridge deck hoisting hanger is set on the cable crane, and the hanger structure is welded from HW300×300×10 / 15mmH-shaped steel and square steel pipes. The hanger has a total of 12 lifting points, 4 lifting points for each bridge deck, and three groups of bridge decks are hoisted as a whole at the same time. After hoisting to the installation position, the bridge decks on both sides are first connected to the large-section steel trusses, and finally the middle bridge deck is installed.

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