Construction method for cable-stayed bridge with single main tower

Abstract

The invention provides a construction method for a single-main-tower cable-stayed bridge. The construction method sequentially comprises the following steps that a main tower is transported to a site in a segmented mode, the main tower is turned over, an operation platform is hung, the main tower is hoisted and welded in the segmented mode, a main inhaul cable is temporarily tied and inserted for construction, and overall finish paint brushing is conducted after main tower construction is completed. By means of dynamic temporary pulling, the modular hoisting technology, the cyclic operation platform and inhaul cable cooperative control, the core problems that in traditional cable-stayed bridge construction, a main tower is unstable, high-altitude operation is low in efficiency, and inhaul cable stress is uneven are systematically solved, and the cable-stayed bridge construction method has the remarkable advantages in safety, economical efficiency and construction period control; the method is suitable for complex construction scenes of large-span single-tower cable-stayed bridges.

Description

Technical Field

[0001] The present invention relates to the technical field of building construction, and in particular to a construction method for a single-main-tower cable-stayed bridge. Background Art

[0002] A cable-stayed bridge is a structure composed of a main tower, main beam, and stay cables. Cables transmit the load from the main beam to the tower, resulting in a long span, lightweight structure, and beautiful appearance. Its construction is complex, requiring coordinated installation and force balance among the tower, main beam, and stay cables.

[0003] At present, the traditional cable-stayed bridge construction method has the following defects: 1. Insufficient stability during main tower construction: During the traditional segmented hoisting process, the main tower is prone to structural deformation or instability due to its tilt angle (6.95°) and high-altitude operation (tower height above the bridge deck is 86.8m), requiring a complex external support system.

[0004] 2. Low hoisting accuracy and efficiency: When hoisting the main tower in sections (16 sections), traditional methods make it difficult to accurately control the inclination angle and positioning posture, resulting in welding misalignment or repeated adjustments, which prolongs the construction period.

[0005] 3. Safety risks of working at height: Traditional operating platforms need to be erected and dismantled multiple times, and personnel frequently go up and down the tower to work, which increases the risk of falling and reduces efficiency.

[0006] 4. Poor coordination of cable tensioning: The traditional tensioning sequence easily leads to uneven stress on the main tower and steel box girder, requiring multiple adjustments to the tensioning force.

[0007] 5. Difficulty in transportation and turning over: The main tower segments are large in size (3.4m across the bridge and 6.5~4.4m along the bridge), and traditional turning over technology can easily cause damage to components or overturning. Summary of the Invention

[0008] In order to solve the above problems, the present invention discloses a construction method for a single-tower cable-stayed bridge.

[0009] The specific plan is as follows: A construction method for a single-main-tower cable-stayed bridge comprises the following steps: transporting the main tower to the site in sections, turning the main tower over and installing an operating platform, hoisting and welding the main tower sections and temporarily tying the main cables, and finally painting the entire main tower after construction is completed.

[0010] Furthermore, the single-tower cable-stayed bridge adopts a single-box 7-chamber continuous steel box girder with a total of three spans; the main beam adopts a steel box girder, and the beam section consists of a top plate, a bottom plate, a longitudinal diaphragm, an outer web plate, an anchor box, a transverse diaphragm, and a wind nozzle block.

[0011] Furthermore, the main tower is divided into 16 sections for processing, transportation and hoisting, numbered T1 to T16 from bottom to top; the main tower is a steel main tower, the steel material is Q345qD, and the total weight is 1,200 tons; the inclination angle is 6.95°, the tower height above the bridge deck is about 86.8m, the cross-section is box-shaped, the transverse width is 3.4m, and the longitudinal direction of the bridge linearly transitions from the bridge deck from 6.5m to 4.4m at the tower top.

[0012] Furthermore, the cables of the single-main-tower cable-stayed bridge are finished epoxy-sprayed parallel steel wire cables, which adopt a double-cable-plane spatial arrangement. The cables are divided into main-span cables and side-span cables. There are 16 pairs of main-span cables in a braided arrangement, with the upper ends anchored on the main towers with a cable spacing of 2 to 3 meters, and the lower ends anchored on the outer steel box girders of the maintenance road with a cable spacing of 6 meters. There are 12 pairs of side-span back cables in a fan-shaped arrangement, with the upper ends anchored on the main towers with a cable spacing of 2.5 to 3 meters, and the lower ends anchored on the central dividing strip of the steel box girders with a cable spacing of 6 meters.

[0013] Furthermore, the construction sequence of the main tower is as follows: (1) Install the main tower sections T1 to T7 in sequence; (2) The T8 section of the main tower is installed, and ZLS16 is installed as a temporary tie measure for the main tower; (3) The main tower T9 section is hoisted and welded in sequence, and ZLS14 is installed as a temporary tie measure for the main tower; (4) Hoist and weld the main tower sections T10 and T11 in sequence, and install ZLS11 as a temporary tie-down measure for the main tower; (5) Hoist and weld the T12 and T13 sections in sequence, and install ZLS6 as a temporary tie measure for the main tower; (6) Hoist and weld the T14 and T15 sections in sequence, and install ZLS1 as a temporary tie measure for the main tower; (7) The main tower T16 section was hoisted and welded. At this point, the main tower construction was completed; (8) The segmented hoisting and welding of the decorative frame is completed, and the main tower construction is completed; (9) After all the steel box girders are hoisted and the entire bridge is welded, all the cables are installed and the tensioning values are adjusted again according to the designed tensioning data. After the tensioning is completed, the reserved holes are sealed and welded, and all the construction is completed.

[0014] Furthermore, during the turning over of the main tower, the main tower segment components need to be turned over and hoisted into place when they are transported to the site. A 7mx7m 1.5m high sand pile is set up on site as a buffer measure for the turning over of the components.

[0015] Furthermore, during the positioning of the main tower, the length of the lifting wire rope is adjusted to ensure that the inclination angle is basically consistent with the positioning angle; before the component is about to be lifted off the ground, the aerial posture of the main tower is checked again and the wire rope is adjusted to ensure that the lifting wire rope is balanced; if there is any deviation, the length of the wire rope is readjusted; after confirmation, the hook is slowly raised until the component leaves the ground, the hook is stopped, and the lifting status of the component is checked again to prepare for formal lifting; limit plates are set at intervals of 1m in the 3.4m width direction on the back of each main tower section. When the upper segment is lifted to the vicinity of the lower segment, the component is slowly moved to the top of the lower segment and slowly lowered. After precise positioning is achieved using the limit plates, temporary welding is performed using the plates, and then full-section welding is performed to complete the installation of this segment.

[0016] Furthermore, during the process of hanging the operating platform on the main tower, a construction operating platform is set up about 1.2m below the interface of each lifting section. The platform width is expanded by 1.0m based on the outer size of the decorative panel. Operators hang a safety rope from the top of each main tower section to reach the operating platform for welding operations. The topcoat construction of the outer surface of the steel tower should be carried out simultaneously with the dismantling of the operating platform.

[0017] Furthermore, the operating platform can be recycled, and the process is as follows: after the welding of two adjacent main tower sections is completed, before the operating platform is dismantled, the wire rope is first hung with the wire rope and the previous main tower, and the wire rope is tightened to ensure the stability of the platform during dismantling; then the operator takes protective measures and stands on the platform to dismantle the connecting parts between the platform and the main tower. When dismantling the platform, the mounting bolts connected to the main body can be removed first, and the node plate can also be cut open together with the gas cutting; the specific dismantling order is first south, then north, and finally east and west sides; the crawler crane lifts the operating platform to the interface of the previous main tower for recycling.

[0018] The beneficial effects of the present invention are: through dynamic temporary tensioning, modular lifting technology, circulating operation platform and coordinated control of cables, it systematically solves the core problems of main tower instability, inefficient high-altitude operations, and uneven cable force in the construction of traditional cable-stayed bridges. It has significant advantages in safety, economy and construction period control, and is suitable for the complex construction scenarios of large-span single-tower cable-stayed bridges. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the main tower section of the present invention.

[0020] Figure 2 Schematic diagram of the construction steps of the main tower (1).

[0021] Figure 3 Schematic diagram of the construction steps (2) of the main tower.

[0022] Figure 4 Schematic diagram of the construction steps (3) of the main tower.

[0023] Figure 5 Schematic diagram of the construction steps (4) of the main tower.

[0024] Figure 6 Schematic diagram of the construction steps (5) of the main tower.

[0025] Figure 7 Schematic diagram of the construction steps (6) of the main tower.

[0026] Figure 8 Schematic diagram of the construction steps (7) of the main tower.

[0027] Figure 9 Schematic diagram of the construction steps (8) of the main tower.

[0028] Figure 10 Schematic diagram of the construction steps (9) of the main tower.

[0029] Figure 11 Schematic diagram of the main tower turning process.

[0030] Figure 12 Schematic diagram of the main tower component hoisting. DETAILED DESCRIPTION

[0031] The present invention will be further explained below in conjunction with specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0032] As shown in the figure, the present invention provides a construction method for a single-main-tower cable-stayed bridge, which includes the following processes in sequence: transporting the main tower to the site in sections, turning the main tower over and hanging an operating platform, hoisting and welding the main tower sections and temporarily tying the main cables in an interspersed manner, and painting the entire main tower after the main tower construction is completed.

[0033] In this embodiment, the single-pylon cable-stayed bridge utilizes a single-box, seven-cell continuous steel box girder with three spans. The main bridge span is 40m + 50m + 110m = 200m, with a deck width ranging from 47.0m to 53m, and a full width of 57m at the main pylon (including decoration). The main girder is a steel box girder, with the beam segments consisting of a top plate, bottom plate (flat or sloped), longitudinal diaphragms, outer webs, anchor boxes, transverse diaphragms, and wind nozzle blocks. The beam height at the centerline is 2.5m (with a horizontal bottom and a 1.5% transverse slope in both directions), and the width varies. The top plate thickness of the box girder segments is available in four different thicknesses: 16mm, 18mm, 20mm, and 40mm (with anchorage areas provided on the longitudinal webs of the steel box girders corresponding to the main pylons). The bottom plate thickness is available in three different thicknesses: 14mm, 16mm, and 25mm. U-ribs and plate ribs are used for stiffening, and the steel box girders are made of Q345qD steel.

[0034] In this embodiment, the main tower is divided into 16 sections for processing, transportation and hoisting, numbered T1 to T16 from bottom to top; the main tower is a steel main tower, the steel material used is Q345qD, and the total weight is 1,200 tons; the inclination angle is 6.95°, the tower height above the bridge deck is about 86.8m, the cross-section is box-shaped, the transverse width is 3.4m, and the longitudinal direction of the bridge linearly transitions from the bridge deck from 6.5m to 4.4m at the tower top. The main tower uses a 400-ton crawler crane and a 500-ton truck crane to assemble and install the steel box girders. The 400-ton crawler crane uses super-lifting working conditions to lift some components, with a super-lifting counterweight of 120t, a turntable counterweight of 130t + a body counterweight of 40t, and a main arm length of 72 meters; the 500-ton crawler crane uses a wind turbine jib with enhanced super-lifting working conditions, a turntable counterweight of 160t + a body counterweight of 40t, a full-load super-lifting counterweight of 190t, a super-lifting mast radius of 13m, a super-lifting counterweight radius of 12-16m, a main arm length of 114 meters + a jib of 12 meters.

[0035] In this embodiment, the cables of the single-main-tower cable-stayed bridge are finished epoxy-sprayed parallel steel wire cables, which adopt a double-cable-plane spatial arrangement. The cables are divided into main-span cables and side-span cables. There are 16 pairs of main-span cables in total, which are arranged in a braided pattern. The upper ends are anchored on the main towers with a cable spacing of 2 to 3 meters, and the lower ends are anchored on the outer steel box girders of the inspection road with a cable spacing of 6 meters. There are 12 pairs of side-span back cables in total, which are arranged in a fan shape. The upper ends are anchored on the main towers with a cable spacing of 2.5 to 3 meters, and the lower ends are anchored on the central dividing strip of the steel box girder with a cable spacing of 6 meters.

[0036] In this embodiment, the construction sequence of the main tower is as follows: (1) Install the main tower sections T1 to T7 in sequence; (2) The T8 section of the main tower is installed, and ZLS16 is installed as a temporary tie measure for the main tower; (3) The main tower T9 section is hoisted and welded in sequence, and ZLS14 is installed as a temporary tie measure for the main tower; (4) Hoist and weld the main tower sections T10 and T11 in sequence, and install ZLS11 as a temporary tie-down measure for the main tower; (5) Hoist and weld the T12 and T13 sections in sequence, and install ZLS6 as a temporary tie measure for the main tower; (6) Hoist and weld the T14 and T15 sections in sequence, and install ZLS1 as a temporary tie measure for the main tower; (7) The main tower T16 section was hoisted and welded. At this point, the main tower construction was completed; (8) The segmented hoisting and welding of the decorative frame is completed, and the main tower construction is completed; (9) After all the steel box girders are hoisted and the entire bridge is welded, all the cables are installed and the tensioning values are adjusted again according to the designed tensioning data. After the tensioning is completed, the reserved holes are sealed and welded, and all the construction is completed.

[0037] In this embodiment, during the turning over of the main tower, the main tower segment components need to be turned over and hoisted into place when they are transported to the site. A 7mx7m 1.5m high sand pile is set up on site as a buffer measure for the turning over of the components.

[0038] In this embodiment, during the positioning of the main tower, the length of the lifting wire rope is adjusted to ensure that the inclination angle is basically consistent with the positioning angle; before the component is about to be lifted off the ground, the aerial posture of the main tower is checked again and the wire rope is adjusted to ensure that the lifting wire rope is balanced; if there is any deviation, the length of the wire rope is readjusted; after confirmation, the hook is slowly raised until the component leaves the ground, the hook is stopped, and the lifting status of the component is checked again to prepare for formal lifting; limit plates are set at intervals of 1m in the 3.4m width direction on the back of each main tower section. When the upper segment is lifted to the vicinity of the lower segment, the component is slowly moved to the top of the lower segment and slowly lowered. After precise positioning is achieved using the limit plates, temporary welding is performed using the plates, and then full-section welding is performed to complete the installation of this segment.

[0039] In this embodiment, during the process of hanging the operating platform on the main tower, a construction operating platform is set up about 1.2m below the interface of each lifting segment. The platform width is expanded by 1.0m based on the outer size of the decorative panel. The operating personnel hang a safety rope from the top of each main tower section to reach the operating platform for welding operations. The topcoat construction of the outer surface of the steel tower should be carried out simultaneously with the removal of the operating platform.

[0040] In this embodiment, the operating platform can be recycled, and the process is as follows: after the welding of two adjacent main tower sections is completed, before the operating platform is dismantled, the wire rope is first hung with the wire rope and the upper main tower, and the wire rope is tightened to ensure the stability of the platform during dismantling; then the operator takes protective measures and stands on the platform to remove the connecting parts between the platform and the main tower. When dismantling the platform, the mounting bolts connected to the main body can be removed first, and the node plate can also be cut open together with the gas cutting; the specific dismantling order is first south, then north, and finally east and west sides; the crawler crane lifts the operating platform to the interface of the upper main tower for recycling.

[0041] The advantages of the present invention are: 1. Improved main tower stability and construction efficiency: Temporary tie-downs (such as ZLS16 and ZLS14) are interspersed throughout the construction process. By installing temporary cables in stages (e.g., ZLS16 after T8), the overturning moment of the main tower is dynamically balanced, avoiding the risk of traditional all-in-one tensioning after the entire tower is completed. Precise positioning with limit plates (set at 1m intervals across a 3.4m width): Using the plates, the upper segment is slowly aligned with the lower segment, reducing manual adjustment time and improving welding accuracy by over 30%.

[0042] 2. Safety and Cost Optimization for High-Aerial Work: A circular operating platform is designed to rise in sections as the main tower is constructed (expanding 1.0 meters outward), reducing the number of erection and dismantling operations. Workers can access the work surface directly via a safety rope, reducing the risk of falls by 50% and shortening the construction period by 15%. Simultaneous topcoat application: Topcoat is applied simultaneously with the platform's dismantling, eliminating the need for dedicated painting equipment later and saving approximately 20% in costs.

[0043] 3. Coordinated Cable Tensioning and Structural Optimization: A dual-cable spatial arrangement combines braided cables (cable spacing 2-3m) in the main span with fan-shaped cables (cable spacing 2.5-3m) in the side spans. This disperses the load transfer path and reduces local stress concentration in the steel box girder (reducing it by 10%-15%). Unified Tensioning Adjustment: After installation, all cables are tensioned again according to design data to eliminate construction errors and ensure uniform cable tension across the entire bridge (error ≤5%).

[0044] 4. Component Transportation and Turnover Safety: Sand pile cushioning measures (7m×7m×1.5m sand pile): During the main tower turnover, the sand pile absorbs impact energy, reducing the risk of component deformation and improving turnover efficiency by 40%. Dynamic wire rope adjustment: During hoisting, the wire rope length is adjusted to match the 6.95° inclination angle, increasing the first-time positioning rate in the air to 95%.

[0045] 5. Material and structural lightweight design: Application of Q345qD steel: The high-strength steel main tower reduces the number of sections (16 sections) while ensuring the bearing capacity, reducing the welding workload by about 20%.

[0046] The technical means disclosed in the solutions of the present invention are not limited to those disclosed in the above-mentioned embodiments, but also include technical solutions composed of any combination of the above-mentioned technical features. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A construction method for a single-tower cable-stayed bridge, characterized in that: The process includes the following steps: transporting the main tower to the site in sections, turning the main tower over and installing the operating platform, hoisting and welding the main tower sections and temporarily tying the main cables, and painting the entire tower after the main tower construction is completed.

2. The construction method for a single-pylon cable-stayed bridge according to claim 1, characterized in that: The single-tower cable-stayed bridge adopts a single-box 7-chamber continuous steel box girder with a total of three spans; the main beam adopts a steel box girder, and the beam section consists of a top plate, a bottom plate, a longitudinal diaphragm, an outer web plate, an anchor box, a transverse diaphragm, and a wind nozzle block.

3. The construction method for a single-pylon cable-stayed bridge according to claim 2, characterized in that: The main tower is divided into 16 sections for processing, transportation and hoisting, numbered T1 to T16 from bottom to top; the main tower is a steel main tower, the steel material used is Q345qD, and the total weight is 1,200 tons; the inclination angle is 6.95°, the tower height above the bridge deck is about 86.8m, the cross-section is box-shaped, the width in the transverse direction of the bridge is 3.4m, and the linear transition along the bridge direction from the bridge deck is 6.5m to 4.4m at the tower top.

4. The construction method for a single-pylon cable-stayed bridge according to claim 2, characterized in that: The cables of the single-main-tower cable-stayed bridge are finished epoxy-sprayed parallel steel wire cables, which adopt a double-cable-plane spatial arrangement. The cables are divided into main-span cables and side-span cables. There are 16 pairs of main-span cables in total, which are arranged in a braided pattern. The upper ends are anchored on the main towers with a cable spacing of 2 to 3 meters, and the lower ends are anchored on the outer steel box girders of the maintenance road with a cable spacing of 6 meters. There are 12 pairs of side-span back cables in total, which are arranged in a fan shape. The upper ends are anchored on the main towers with a cable spacing of 2.5 to 3 meters, and the lower ends are anchored on the central dividing strip of the steel box girder with a cable spacing of 6 meters.

5. The construction method for a single-pylon cable-stayed bridge according to claim 1, characterized in that: The construction sequence of the main tower is as follows: (1) Install the main tower sections T1 to T7 in sequence; (2) The T8 section of the main tower is installed, and ZLS16 is installed as a temporary tie measure for the main tower; (3) The main tower T9 section is hoisted and welded in sequence, and ZLS14 is installed as a temporary tie measure for the main tower; (4) Hoist and weld the main tower sections T10 and T11 in sequence, and install ZLS11 as a temporary tie-down measure for the main tower; (5) Hoist and weld the T12 and T13 sections in sequence, and install ZLS6 as a temporary tie measure for the main tower; (6) Hoist and weld the T14 and T15 sections in sequence, and install ZLS1 as a temporary tie measure for the main tower; (7) The main tower T16 section was hoisted and welded. At this point, the main tower construction was completed; (8) The segmented hoisting and welding of the decorative frame is completed, and the main tower construction is completed; (9) After all the steel box girders are hoisted and the entire bridge is welded, all the cables are installed and the tensioning values are adjusted again according to the designed tensioning data. After the tensioning is completed, the reserved holes are sealed and welded, and all the construction is completed.

6. The construction method for a single-pylon cable-stayed bridge according to claim 1, characterized in that: During the turning over of the main tower, the main tower segment components need to be turned over and hoisted into place when they are transported to the site. A 7mx7m 1.5m high sand pile is set up on site as a buffer measure for the turning over of the components.

7. The construction method for a single-pylon cable-stayed bridge according to claim 1, characterized in that: During the main tower installation process, the length of the hoisting wire rope is adjusted to ensure that the inclination angle is basically consistent with the installation angle; before the component is about to be lifted off the ground, the main tower's aerial posture is checked again and the wire rope is adjusted to ensure that the hoisting wire rope is balanced in force; If there is any deviation, readjust the length of the wire rope; after confirmation, slowly lift the hook until the component leaves the ground, stop lifting the hook, check the lifting status of the component again, and prepare for formal lifting; set limit plates at intervals of 1m in the 3.4m width direction on the back of each main tower section. When the upper segment is hoisted to the vicinity of the lower segment, slowly move the component to the top of the lower segment and slowly lower it. After precise positioning using the limit plates, use the plates for temporary welding, and then perform full-section welding to complete the installation of this segment.

8. The construction method for a single-pylon cable-stayed bridge according to claim 1, characterized in that: During the process of hanging the operating platform on the main tower, a construction operating platform is set up about 1.2m below the interface of each lifting section. The width of the platform is expanded by 1.0m based on the outer size of the decorative panel. Operators hang a safety rope from the top of each main tower section to reach the operating platform for welding operations. The paint application on the outer surface of the steel tower should be carried out simultaneously with the removal of the operating platform.

9. The construction method for a single-pylon cable-stayed bridge according to claim 1, characterized in that: The operating platform can be recycled, and the process is as follows: after the welding of two adjacent main tower sections is completed, before the operating platform is dismantled, the wire rope is first hung with the wire rope and the upper main tower, and the wire rope is tightened to ensure the stability of the platform when it is dismantled; then the operator takes protective measures and stands on the platform to dismantle the connecting parts between the platform and the main tower. When dismantling the platform, the mounting bolts connected to the main body can be removed first, and the node plate can also be cut open together with the gas cutting; the specific dismantling order is first south, then north, and finally east and west sides; the crawler crane lifts the operating platform to the interface of the upper main tower for recycling.

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