Single-cantilever tower beam synchronous construction method of steel truss girder cable-stayed bridge

Abstract

The present application relates to the technical field of bridge construction, and particularly relates to a steel truss girder cable-stayed bridge single cantilever tower girder synchronous construction method. When the tower column in the cable tower is constructed upward, the pier top section is synchronously installed, and the bridge longitudinal and transverse direction limiting is set; after the erection of the steel truss girder side span section is completed, the full-rotation crane is installed on the side span section by the tower crane, and the cable tower is constructed to the corresponding section; with the upward construction of the cable tower, the steel truss girder is continuously installed to the single cantilever of the midspan side, the cable on the side of the midspan and the side span is symmetrically installed and tensioned, and the whole bridge is closed. The cable tower and the steel truss girder single cantilever construction are simultaneously performed, and the problems of high cost and slow progress of the traditional construction scheme are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bridge construction, in particular to a single cantilever tower beam synchronous construction method for steel truss girder cable-stayed bridge. BACKGROUND

[0002] The steel truss girder cable-stayed bridge is the most common bridge type of large-span highway-railway cable-stayed bridge. It is favored by engineers due to its stable structure system, mature construction method, highway layer and railway layer partitioning without interference, and many other advantages. In recent years, a large number of large-span highway-railway cable-stayed bridges such as Shanghai-Suzhou-Tongling Yangtze River Highway-Railway Bridge, Wuhu Yangtze River Highway-Railway Bridge of Shanghehang Railway, Tongling Yangtze River Highway-Railway Bridge, and Baijusi Yangtze River Bridge have been built and put into operation, creating good economic and social benefits. The construction method of steel truss girder cable-stayed bridge is greatly influenced by the cable tower shape, structure characteristics, topography, and construction site conditions. The overall construction method of the main girder has double cantilever whole segment installation method, double cantilever scattered splicing method, incremental launching method, and shore side incremental launching midspan cantilever scattered splicing method. The construction method of the steel truss girder pier top section has whole segment hoisting method, scattered splicing method, and scattered splicing sliding method.

[0003] For the construction of steel truss girder cable-stayed bridge on non-navigable rivers, when the incremental launching method is used, temporary support piers need to be installed in the river area, and temporary steel bridges need to be constructed accordingly. This not only affects the safety of flood discharge, but also has high cost. When the double cantilever scattered splicing method is used, two rotary cranes need to be used at the same time, and a strong temporary consolidation needs to be set at the pier top. On the one hand, this increases the cost of temporary consolidation measures, and on the other hand, it increases the difficulty of main girder construction, and does not fully utilize the favorable topography of the side span in the floodplain area.

[0004] In the traditional tower beam synchronous construction of steel truss girder cable-stayed bridge, when the steel truss girder segment installation and cable stay tensioning are performed on the side of the midspan, the main tower has been capped. Its main disadvantage is that the steel truss girder segment installation cannot be performed until the tower is capped, and the steel truss girder installation cannot be performed simultaneously with the tower construction. Therefore, the construction period is long.

[0005] For the steel truss girder cable-stayed bridge that crosses non-navigable rivers and has a main pier located in the floodplain area, a new construction method needs to be found to reduce construction cost and speed up construction progress. SUMMARY

[0006] The present application provides a single cantilever tower beam synchronous construction method for steel truss girder cable-stayed bridge to solve the problems of the prior art.

[0007] The present application is achieved by the following technical solutions:

[0008] A single cantilever tower beam synchronous construction method for steel truss girder cable-stayed bridge, comprising the following steps:

[0009] Step one: construction of the main pier cable tower, concrete bracket, lower beam and auxiliary pier, side pier; main pier pile cap and tower base construction, install pier bracket pre-buried parts in advance on the concrete surface, main pier cable tower segment and pier bracket are constructed synchronously, install temporary support pier in the side span position, install side span side gantry crane.

[0010] Step two: use hydraulic climbing formwork to construct the main pier tower column, use crawler crane to install the lower chord of the top segment of the pier, slide the track along the bridge direction, adjust the vertical jack, install the lower chord and the lower bridge system on the temporary support pier of the side span side, connect them into a whole by high-strength bolts, pull the specified position by horizontal pulling jack and precision rolled thread steel, lift the lower chord and remove the sliding track along the bridge direction, and then lower the lower chord to the permanent support and fix it with the steel plate on the permanent support.

[0011] Step three: install the straight web member, inclined web member, upper chord, upper bridge system and inclined strut in sequence, install the sliding track along the transverse bridge direction on the cable tower lower beam, slide the vice truss along the transverse bridge direction to the specified position by horizontal pulling jack and precision rolled thread steel, adjust the position of the vice truss by vertical adjusting jack, connect it with the inclined strut, install the upper bridge system, and complete the installation of the steel member of the top segment of the pier.

[0012] Step four: use crawler crane to install the remaining steel truss member of the top segment of the pier in sequence; install the limit along the bridge direction and the limit along the transverse bridge direction on the permanent support of the top segment of the pier.

[0013] Step five: construct the upper tower column of the cable tower, install the first steel anchor beam and cable guide pipe; use gantry crane to install the steel truss from the middle span to the side span, until the steel truss of the side span of the main bridge is completely installed.

[0014] Step six: continue to construct the cable tower upward, install the rotary crane at the side span position by tower crane, and install the beam transport trolley on the upper bridge.

[0015] Step seven: continue to construct the cable tower upward by hydraulic climbing formwork, install the steel anchor beam and cable guide pipe from bottom to top in sequence; when the hydraulic climbing formwork is climbing, the outlet end of the cable guide pipe is exposed and has the installation condition of the cable-stayed cable, install the first segment of the steel truss on the side span of the middle span by rotary crane, install the first segment of the cable-stayed cable on the side span of the middle span and the first segment of the cable-stayed cable on the side span of the side span, and tension them, and then remove the pier bracket.

[0016] Step eight: continue to install the steel truss to the middle span side by single cantilever method as the cable tower is constructed upward, tension the corresponding cable-stayed cable on the side span of the middle span and the side span of the side span symmetrically, remove the temporary support pier of the steel truss before tensioning the cable-stayed cable on the side span of the side span, and remove the hydraulic climbing formwork after the cable tower is capped.

[0017] Step nine: the main bridge continues the cantilever construction to the closure, removes the main pier pier order bridge direction limit and horizontal bridge direction limit, adjusts the cable force, adjusts the angle and elevation, plane deviation of the steel truss girder at both ends of the closure, and installs the closure section steel truss girder by using the bridge crane.

[0018] Step ten: adjusting the cable force, installing the steel truss girder damper, and constructing the bridge deck system and auxiliary structure.

[0019] As a preferred scheme:

[0020] In the step two, the longitudinal sliding track is made of profile steel, is arranged along the center of the lower chord, and the top elevation of the longitudinal sliding track is 5-10 cm higher than the permanent support; the bottom of the longitudinal sliding track is supported on the concrete bracket top surface or pier side support distribution beam by using a steel plate, and temporary pads and vertical adjusting jacks are arranged at both ends of the permanent support; the tensioning reaction seat is arranged on the top of the longitudinal sliding track on the side of the midspan, the fixed end of the fine rolled thread steel is anchored on the lower chord end customized tool, the fine rolled thread steel is tensioned by using a horizontal pulling jack, and the lower chord and the lower bridge deck are longitudinally slid.

[0021] In the step three, the pier top center bay straight web, upper chord, upper bridge deck system and inclined strut are hoisted and positioned by using a crawler crane, and the sub-truss is positioned by using a horizontal sliding pulling method.

[0022] In the step three, the horizontal sliding track is arranged on the top surface of each cable tower lower cross beam, after being slid to the specified position, the vertical adjusting jack is used to lift the sub-truss, and then the horizontal sliding track is removed, the beam is lowered and connected with the inclined strut.

[0023] In the step five, before the steel truss reaches the next group of temporary support piers, the vertical adjusting jack on the previous group of temporary support piers is used to lift the steel truss, the lifting height is consistent with the deflection height of the steel truss between the two temporary support piers, and it is ensured that the steel truss can pass through the hole smoothly.

[0024] In the step seven, the cable installation condition is that the cable steel anchor beam of the first segment on the side of the midspan and the side span has completed the circumferential prestress construction, the concrete age of the tower column segment meets the 28-day requirement, and 2-3 tower column segments above the tower column segment have been completed, after the hydraulic climbing formwork climbs, the cable guide pipe is exposed on the outer surface of the tower column.

[0025] In the step nine, when the cable tower is capped, the cable completes 1 / 3-1 / 2 of the total number of installation and tensioning operations.

[0026] The cable tower and the steel truss unilateral cantilever construction are carried out simultaneously, the problems of high cost and slow progress in the traditional construction scheme are solved, new designs are carried out in each construction stage, and the construction cost can be significantly reduced, the construction progress can be accelerated, and the total project cost can be saved.

[0027] Additional advantages, objects, and features of the application will be apparent from the following description, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The embodiment of the steel truss girder cable-stayed bridge longitudinal section layout;

[0029] Figure 2 The embodiment of the steel truss girder cable-stayed bridge cable tower modeling cross section structure schematic diagram;

[0030] Figure 3 The embodiment of the steel truss girder cable-stayed bridge cable tower modeling longitudinal section structure schematic diagram;

[0031] Figure 4 The embodiment of the steel truss girder structure schematic diagram;

[0032] Figure 5 The embodiment of the construction step one schematic diagram;

[0033] Figure 6 The embodiment of the step two pier top center section lower chord and lower bridge floor system assembly cross section schematic diagram;

[0034] Figure 7 The embodiment of the step two pier top center section lower chord and lower bridge floor system assembly longitudinal section schematic diagram;

[0035] Figure 8 The embodiment of the step two pier top center section lower chord and lower bridge floor system sliding schematic diagram;

[0036] Figure 9 The embodiment of the step two pier top center section lower chord and lower bridge floor system beam falling adjustment schematic diagram;

[0037] Figure 10 The embodiment of the step three pier top center section straight web member, upper chord and other installation cross section schematic diagram;

[0038] Figure 11 The embodiment of the step three pier top center section straight web member, upper chord and other installation longitudinal section schematic diagram;

[0039] Figure 12 The embodiment of the step three pier top center section auxiliary truss rod sliding installation cross section schematic diagram;

[0040] Figure 13 The embodiment of the step three pier top center section auxiliary truss rod sliding installation longitudinal section schematic diagram;

[0041] Figure 14 The embodiment of the step four schematic diagram;

[0042] Figure 15 Figure 4 is a schematic view of the remaining steel truss girder component installation of the step four of the embodiment;

[0043] Figure 16 Figure 5 is a schematic view of the step five of the embodiment;

[0044] Figure 17 Figure 6 is a schematic view of the step six of the embodiment;

[0045] Figure 18 Figure 7 is a schematic view of the step seven of the embodiment;

[0046] Figure 19 Figure 8 is a schematic view of the step eight of the embodiment;

[0047] Figure 20 Figure 9 is a schematic view of the maximum cantilever state of the steel truss girder of the step nine of the embodiment;

[0048] Figure 21 Figure 10 is a schematic view of the closure segment construction of the steel truss girder of the step nine of the embodiment.

[0049] In the figure: 1, cable tower, 2, lower tower column, 3, concrete bracket, 4, lower cross beam, 5, middle tower column, 6, upper tower column, 7, permanent support, 8, steel truss girder, 9, cable guide pipe, 10, steel anchor beam, 11, lower chord, 12, upper chord, 13, lower bridge deck system, 14, upper middle bridge deck system, 15, auxiliary truss rod, 16, upper edge bridge deck system, 17, straight web member, 18, inclined web member, 19, inclined strut, 20, auxiliary pier, 21, side pier, 22, hydraulic climbing formwork, 23, tower crane, 24, pier-side bracket, 25, temporary support pier, 26, gantry crane, 27, bridge longitudinal sliding track, 28, vertical adjustment jack, 29, temporary cushion block, 30, crawler crane, 31, counter-force seat, 32, horizontal pulling jack, 33, finished rolling threaded steel, 34, bridge transverse sliding track, 35, rotary crane, 36, beam transport trolley, 37, cable-stayed cable, 38, bridge longitudinal limit, 39, bridge transverse limit, 40, closure segment steel truss girder. DETAILED DESCRIPTION

[0050] The present application will be further described in detail with reference to the accompanying drawings, so that those skilled in the art can implement the present application according to the description.

[0051] It should be noted that the experimental methods in the following embodiments are conventional methods, and the reagents and materials are commercially available unless otherwise specified. In the description of the present application, the terms "transverse", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0052] As shown in the accompanying Figure 1 The main bridge of the steel truss girder cable-stayed bridge of the embodiment is a double-tower five-span steel truss girder cable-stayed bridge, the main piers, auxiliary piers 20 and side piers 21 are located in the bank side beach area and are not disturbed by flood.

[0053] As shown in the accompanying Figures 2-4 The cable tower 1 of the steel truss girder 8 cable-stayed bridge is in the shape of a bottle as a whole, and the cable tower 1 includes a lower tower column 2, a concrete bracket 3, a lower cross beam 4, a middle tower column 5 and an upper tower column 6. The steel truss girder 8 is in the shape of an inverted trapezoid, and the steel truss girder 8 includes a lower chord 11, an upper chord 12, a lower bridge deck system 13, an upper middle bridge deck system 14, a secondary truss rod 15, an upper side bridge deck system 16, a straight web member 17, an inclined web member 18 and an inclined strut 19. The lower tower column 2 of the cable tower 1 is inclined outward, the middle tower column 5 is inclined inward, and the upper tower column 6 is perpendicular upward after closure, gradually changing upward along the cross section to the tower crown. The inner side wall of the lower tower column 2 is provided with the concrete bracket 3, the permanent support 7 is installed on the concrete bracket 3, and the concrete bracket 3 is a vertical main force member of the steel truss girder 8. There are two lower cross beams 4 in total, and there is a certain spacing between the cross beams. The straight web member 17 of the pier top segment of the steel truss girder 8 passes through the two lower cross beams 4 of the cable tower 1. The upper chord 12, the secondary truss rod 15, the upper middle bridge deck system 14 and the upper side bridge deck system 16 are all located above the lower cross beam 4 of the cable tower 1. The upper tower column 6 segment of the cable tower 1 is provided with a steel anchor beam 10 and a cable guide pipe 9.

[0054] The single cantilever tower girder synchronous construction method of the steel truss girder cable-stayed bridge of the embodiment includes the following steps:

[0055] Step one: as shown in the accompanying Figure 5 The lower tower column 2, the concrete bracket 3 and the lower cross beam 4 of the main pier cable tower 1, the auxiliary pier 20 and the side pier 21 are constructed. The pier side bracket 24 preformed parts are installed on the surface of the concrete during the construction of the main pier pile cap and the tower base. The main pier cable tower 1 segment is constructed synchronously with the pier side bracket 24. The temporary support pier 25 at the side span position is installed, and the side span side gantry crane 26 is installed.

[0056] Step two: as shown in the accompanying Figures 6-9As shown, the main pier tower column 5 is constructed using hydraulic climbing formwork 22. A crawler crane 30 is used to install the lower chord 11 of the pier top section along the bridge direction sliding rail 27, vertical adjusting jacks 28, and temporary pads 29. The lower chord 11 and the lower bridge deck system 13 are installed on the bridge direction sliding rail 27 on the top of the temporary support pier 25 on the side span. They are connected into a whole using high-strength bolts. After being dragged to the designated position using horizontal dragging jacks 32 and precision-rolled threaded steel bars 33, the lower chord 11 is lifted and the bridge direction sliding rail 27 is removed. The lower chord 11 is then lowered onto the permanent support 7 and bolted to the steel plate on the permanent support 7.

[0057] In step two, the longitudinal sliding track 27 is made of steel and is arranged along the center of the lower chord 11. The top elevation of the longitudinal sliding track 27 is 5-10cm higher than that of the permanent support 7. The bottom of the track is supported by steel plates on the top surface of the concrete corbel 3 or the distribution beam of the pier support. Temporary pads 29 and vertical adjusting jacks 28 are set at both ends of the permanent support 7. The tensioning reaction seat 31 is set on the top of the longitudinal sliding track 27 on the mid-span side. The fixed end of the precision-rolled threaded steel bar 33 is anchored to the customized tooling at the end of the lower chord 11. The horizontal drag jack 32 is used to tension the precision-rolled threaded steel bar 33 to realize the longitudinal sliding of the lower chord 11 and the lower bridge deck.

[0058] Step 3: As attached Figures 10-13 As shown, the straight web members 17, diagonal web members 18, upper chord members 12, upper and middle bridge deck system 14, and diagonal bracing members 19 of the pier top section are installed in sequence. A transverse bridge sliding track 34 is installed on the lower crossbeam 4 of the pylon 1. The secondary truss 15 is slid to the designated position along the transverse bridge direction using horizontal drag jacks 32 and precision rolled threaded steel bars 33. The position of the secondary truss 15 is adjusted using vertical adjustment jacks 28 and connected to the diagonal bracing members 19. The upper bridge deck system 16 is then installed, completing the installation of the entire pier top section steel components.

[0059] In step three, the straight web members 17, diagonal web members 18, upper chord members 12, upper bridge deck system, and diagonal bracing members 19 in the central section of the pier top can all be hoisted into place by crawler crane 30. The secondary truss 15 cannot be hoisted into place due to the inward inclination of the central tower column 5, and is instead placed by lateral sliding and dragging method.

[0060] In step three, a transverse sliding track 34 is set on the top surface of the lower crossbeam 4 of the tower 1. After sliding to the designated position, the secondary truss 15 is lifted by the vertical adjusting jack 28 and then the transverse sliding track 34 is removed. The beam is then lowered and connected to the diagonal brace 19.

[0061] Step Four: As attached Figures 14-15 As shown, crawler crane 30 is used to install the remaining steel truss girder 8 components on the middle span and side span of the pier top section in sequence. At the bottom surface of the lower chord 11 of the steel truss girder 8, the permanent support 7 at the pier top is installed with longitudinal limiters 38 and transverse limiters 39 on both sides in the longitudinal and transverse directions.

[0062] Step five: as shown in the attached Figure 16 Figure 5, the tower column 6 is constructed on the cable tower 1, the first section of steel anchor beam 10 and the cable guide pipe 9 are installed; the gantry crane 26 is used to install the steel truss 8 from the midspan to the side span, and the installation of the steel truss 8 on the side span of the main bridge is completed.

[0063] In the step five, before the steel truss 8 reaches the next group of temporary support piers 25, the vertical adjusting jack 28 on the previous group of temporary support piers 25 is used to lift the steel truss 8, and the lifting height is consistent with the sag height of the steel truss 8 between the two temporary support piers 25, so as to ensure that the steel truss 8 can pass through the hole smoothly.

[0064] Step six: as shown in the attached Figure 17 Figure 6, the cable tower 1 continues to be constructed upward, the rotary crane 35 is installed at the side span position by using the tower crane 23, and the beam transporting trolley 36 is installed on the upper bridge deck.

[0065] Step seven: as shown in the attached Figure 18 Figure 7, the cable tower 1 continues to be constructed upward by using the hydraulic climbing formwork 22, and the steel anchor beam 10 and the cable guide pipe 9 are installed in sequence from bottom to top after entering the cable zone; when the outlet end of the cable guide pipe 9 is exposed and has the installation conditions of the cable-stayed cable 37, the first section of the steel truss 8 on the first section of the segment on the midspan side is installed by using the rotary crane 35, the cable-stayed cable 37 on the first section of the segment on the midspan side and the cable-stayed cable 37 on the first section of the segment on the side span are symmetrically installed, tensioned, and the pier-side bracket 24 is removed.

[0066] In the step seven, the installation of the cable-stayed cable 37 on the first section of the segment on the midspan side and the first section of the segment on the side span should meet the following conditions: the tower column segment where the steel anchor beam 10 of the cable-stayed cable 37 on the first section of the segment on the midspan side and the first section of the segment on the side span is located has completed the circumferential prestress construction, the concrete age of the tower column segment meets the requirement of 28 days, and 2-3 tower column segments above the tower column segment have been constructed, the cable guide pipe 9 has been exposed on the outer surface of the tower column after the hydraulic climbing formwork 22 is climbed, and the cable-stayed cable 37 on the first section of the segment on the midspan side and the first section of the segment on the side span is synchronously threaded and tensioned at 4 points on the upstream and downstream sides.

[0067] Step eight: as shown in the attached Figure 19 Figure 8, as the cable tower 1 continues to be constructed upward, the steel truss 8 is installed toward the midspan side by using the single cantilever method, the corresponding cable-stayed cable 37 on the midspan side and the side span is symmetrically tensioned, the temporary support pier 25 under the steel truss 8 is removed in advance before the cable-stayed cable 37 on the side span is tensioned, the hydraulic climbing formwork 22 is removed after the cable tower 1 is capped.

[0068] Step nine: as shown in the attached Figures 20-21 Figure 9, the main bridge continues to be cantilever constructed to the closure, the pier order bridge direction limit 38 and the transverse bridge direction limit 39 of the main pier are removed, the angles and elevations of the steel truss 8 at both ends of the closure are adjusted, the plan deviation is adjusted by adjusting the cable force of the cable-stayed cable 37, and the closure section steel truss 40 is installed by using the bridge deck crane.

[0069] When the tower 1 is capped, the cable 37 will complete 1 / 3 to 1 / 2 of the total number of installation tensioning operation, the remaining cable 37 and steel truss 8 installation is not affected by the tower 1 construction.

[0070] Step ten: adjust the cable 37 cable force, install steel truss 8 damper, bridge system and auxiliary structure.

[0071] While the embodiments of the application have been disclosed as above, it is not limited to the use only as set forth in the specification and examples, it can be fully applied to various fields suitable for the application, and additional modifications can be easily made by those skilled in the art, therefore the application is not limited to specific details and the figures shown and described herein, without departing from the general concept defined by the claims and the equivalent scope.

Claims

1. A steel truss girder cable-stayed bridge single cantilever tower girder synchronous construction method, comprising the following steps: Step one: construction of the main pier cable tower (1), the lower tower column (2), the concrete corbel (3), the lower cross beam (4), the auxiliary pier (20) and the side pier (21); when the main pier pile cap and tower base are constructed, the pier side bracket (24) pre-buried part is installed on the surface of the concrete in advance, the main pier cable tower (1) segment is constructed synchronously with the pier side bracket (24), the temporary support pier (25) in the side span position is installed, and the side span side gantry crane (26) is installed; Step two: the main pier middle tower column (5) is constructed by using the hydraulic climbing formwork (22), the pier top section lower chord (11) sliding track (27) in the bridge direction, vertical adjusting jack (28) and temporary cushion block (29) are installed by using the crawler crane (30), the lower chord (11) and the lower bridge deck system (13) are installed on the sliding track (27) in the bridge direction on the top of the temporary support pier (25) in the side span position, they are connected into a whole by using high-strength bolts, the horizontal pulling jack (32) and the fine rolled threaded steel (33) are pulled to the specified position, the lower chord (11) is jacked up and the sliding track (27) in the bridge direction is removed, the lower chord (11) is lowered to the permanent support (7) and is bolted and fixed with the steel plate on the permanent support (7); Step three: the pier top section straight web member (17), the inclined web member (18), the upper chord (12), the upper middle bridge deck system (14) and the inclined brace (19) are installed in sequence, the transverse bridge direction sliding track (34) is installed on the cable tower (1) lower cross beam (4), the horizontal pulling jack (32) and the fine rolled threaded steel (33) are used to slide the auxiliary truss (15) to the specified position in the transverse bridge direction, the vertical adjusting jack (28) is used to adjust the position of the auxiliary truss (15) and connect it with the inclined brace (19), the upper side bridge deck system (16) is installed, and the installation of the whole pier top section steel member is completed; Step four: the crawler crane (30) is used to install the remaining steel truss girder (8) members in the pier top section middle span and side span in sequence; the bridge direction limit (38) and the transverse bridge direction limit (39) are installed on the pier top permanent support (7) on both sides of the lower chord (11) of the steel truss girder (8) in the bridge direction and the transverse bridge direction; Step five: the upper tower column (6) of the cable tower (1) is constructed, the first section steel anchor beam (10) and the cable guide pipe (9) are installed; the steel truss girder (8) is installed from the middle span to the side span by using the gantry crane (26), and the installation of the steel truss girder (8) in the main bridge side span is completed; Step six: the cable tower (1) continues to be constructed upwards, the slewing crane (35) is installed at the side span position by using the tower crane (23), and the beam transporting trolley (36) is installed on the upper bridge deck; Step seven: the cable tower (1) continues to be constructed upwards by using the hydraulic climbing formwork (22), the steel anchor beam (10) and the cable guide pipe (9) are installed in sequence from bottom to top after entering the anchor cable area; when the hydraulic climbing formwork (22) climbs, the outlet end of the cable guide pipe (9) is exposed and has the installation condition of the cable-stayed cable (37), the first section steel truss girder (8) in the middle span side is installed by using the slewing crane (35), the first section cable-stayed cable (37) in the middle span side and the first section cable-stayed cable (37) in the side span side are symmetrically installed and tensioned, the pier side bracket (24) is removed. Step eight: as the tower (1) upward construction, continue to install steel truss girder (8) in the middle of the single cantilever method to the side, symmetrically tensioned across the side, side span side corresponding cable (37), before the side span cable (37) tension, remove the steel truss girder (8) under the temporary support pier (25), tower (1) after the top, remove the hydraulic climbing formwork (22); Step nine: the main bridge continues to cantilever construction to the closure, remove the main pier along the bridge limit (38) and transverse bridge limit (39), by adjusting the cable (37) cable force, adjust the closure of the two ends of the steel truss girder (8) angle and elevation, plane deviation, using the bridge crane installation closure section steel truss girder (40); Step ten: adjust the cable (37) cable force, install steel truss girder (8) damper, bridge deck system and auxiliary structure.

2. The method according to claim 1, characterized in that: In the step two, the along the bridge direction sliding track (27) is made of profile steel, arranged along the center of the lower chord (11) in the along the bridge direction, the top of the along the bridge direction sliding track (27) is 5-10 cm higher than the permanent support (7), the bottom of the along the bridge direction sliding track (27) is supported on the concrete corbel (3) top surface or pier beside the support beam by steel plate, the both ends of the permanent support (7) are provided with temporary cushion (29) and vertical adjusting jack (28); the tensioning reaction seat (31) is arranged on the top of the along the bridge direction sliding track (27) in the middle span side, the fixed end of the fine rolled thread steel (33) is anchored on the end of the lower chord (11) customized tool, the fine rolled thread steel (33) is tensioned by horizontal dragging jack (32), and the lower chord (11) and the lower bridge deck are slid in the along the bridge direction.

3. The method according to claim 1, characterized in that: In the step three, the pier top center segment straight web member (17), upper chord (12), upper bridge deck system and diagonal bracing (19) are hoisted and positioned by crawler crane (30), and the sub truss member (15) is positioned by horizontal sliding dragging method.

4. The method according to claim 1, characterized in that: In the step three, the transverse bridge direction sliding track (34) is arranged on the top surface of the tower (1) lower cross beam (4), the sub truss member (15) is lifted by vertical adjusting jack (28) after sliding to the specified position, and then the transverse bridge direction sliding track (34) is removed, the beam is lowered and connected with the diagonal bracing (19).

5. The method according to claim 1, wherein the method is characterized by: In the step five, before the steel truss girder (8) reaches the next group of temporary support piers (25), the steel truss girder (8) needs to be jacked up by the vertical adjusting jack (28) on the previous group of temporary support piers (25), the jacking height is consistent with the sag height of the steel truss girder (8) between the two temporary support piers (25), so that the steel truss girder (8) can smoothly pass through the hole.

6. The method according to claim 1, wherein the method is characterized by: In the step seven, the cable (37) installation condition is that the first segment cable (37) steel anchor beam (10) of the middle span and side span is located in the tower column segment which has completed the ring prestress construction, the concrete age of the tower column segment meets the requirement of 28 days, and 2-3 tower column segments above the tower column segment have been completed, the cable guide pipe (9) has been exposed on the outer surface of the tower column after the hydraulic climbing formwork (22) climbs up.

7. The method according to claim 1, wherein the method is characterized by: In the step nine, when the tower (1) is capped, the cable (37) needs to complete 1 / 3-1 / 2 of the total number of installation and tensioning operation.

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