A vertical turning method for a single-tower double-layer steel truss girder cable-stayed bridge main tower

Abstract

The present application relates to the vertical rotation technical field of cable-stayed bridge main tower, and discloses a vertical rotation method of single-tower double-layer steel truss girder cable-stayed bridge main tower, which is characterized by comprising the following steps: S1, a temporary assembling platform is erected on the bridge deck, the main tower structure is assembled at 5 degrees with the bridge deck, and the overall assembly is completed on the bridge deck; S2, a vice tower is assembled, two side hoisting cages, compression rods, flexible pull rods, cable anchors, back cable anchors, steel strand jacks and the like are installed, the vice tower portal frame is installed on the main tower, the front pull anchor points are arranged on the main tower, the rear pull anchor points are arranged on the bridge deck, the main tower is assembled on the bridge deck, the construction condition is better, the welding quality is more easily controlled, the main tower installation time is greatly shortened, the temporary equipment investment is saved, the construction machinery cost is greatly reduced, and the structural safety is more easily guaranteed, and meanwhile, the main tower structure is assembled at 5 degrees with the bridge deck, so that it is easier to pull than directly in the horizontal direction.

Description

Technical Field

[0001] This invention relates to the field of vertical rotation technology for the main tower of a cable-stayed bridge, specifically a method for vertical rotation of the main tower of a single-tower, double-layer steel truss cable-stayed bridge. Background Technology

[0002] In recent years, with the emergence of new processes, materials, and technologies, various new types of bridge structures have also appeared. For the vertical rotation of the main tower of a cable-stayed bridge, the sectional assembly method is mostly used. While this method saves a significant amount of specialized machinery and equipment, it also has many drawbacks. First, it places extremely high demands on temporary supports, which are installed at high heights, require a large quantity, pose significant risks, have long construction periods, are difficult to control in terms of welding quality and linearity, and involve many uncertainties. Second, high-altitude welding is highly dangerous, difficult to control in terms of welding quality, and involves a large welding workload. Third, high-altitude installation operations are difficult to control in terms of precision and have relatively long construction periods. Summary of the Invention

[0003] (a) Technical problems to be solved

[0004] To address the shortcomings of existing technologies, this invention provides a method for vertically rotating the main tower of a single-tower, double-layer steel truss cable-stayed bridge, thus solving the problems mentioned in the background section.

[0005] (II) Technical Solution

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for vertically rotating the main tower of a single-tower, double-layer steel truss cable-stayed bridge, characterized by comprising the following steps:

[0007] S1. A temporary assembly platform is set up on the bridge deck. The main tower structure is assembled at a 5° angle to the bridge deck, and the overall assembly is completed on the bridge deck.

[0008] S2. Assemble the secondary tower, install the two side cages, pressure rods, flexible tie rods, cable anchors, back cable anchors, steel strand jacks, etc., and install the secondary tower gantry on the main tower. Set the front anchor on the main tower and the rear anchor on the bridge deck.

[0009] S3. The steel strand traction cable and back cable are threaded with the steel strands. The steel strand traction cable and the steel strand tie rod are pre-tightened simultaneously. Each steel strand of the steel strand tie rod is pre-tightened by about 1t, and each steel strand is of equal length.

[0010] S4. Pay attention to the weather forecast in advance and make preparations before vertical rotation. Choose a windless day (or wind speed less than level 4) for vertical rotation.

[0011] S5. Pre-tension the anchor cables to make the secondary tower tensioned and form a stable triangular structure. Remove the pressure bar assembly support, then debug the steel strand jack synchronous vertical rotation system equipment, and then test the vertical rotation.

[0012] S6. The front end of the main tower detaches approximately 5cm from the assembly platform. Observe it statically for about one hour, checking the temporary vertical rotation structure, stabilizing cable system, vertical rotation system, foundation, lifting points, bottom hinge points, etc. Only after confirming that the entire vertical rotation process is absolutely safe can the formal vertical rotation begin.

[0013] S7. Use continuous steel strand jacks to gradually tension the anchor cables to make the main tower rotate vertically. While rotating vertically, monitor and control each structure. Rotate the main tower to 45°. During the rotation, closely monitor the tension of the traction cable. If the tension of a single steel strand is less than 4t, stop the rotation operation in time and report to the command personnel.

[0014] S8. When the main tower rotates to 60°, stop the rotation traction, then tension the back cable. When the main tower rotates to 75°, adjust the back cable to the specified tension.

[0015] S9. The main tower is rotated vertically to a position close to the design position. Measurement and control are performed to slow down the vertical rotation speed. The main tower is then finely adjusted in the vertical direction for precise positioning. The main tower interface is then welded, the rotating structure is dismantled, and the main tower rotation is completed.

[0016] Preferably, the pre-tensioned anchor cables are loaded step by step using continuous jacks, maintaining synchronization. The difference in pre-tension force between each jack should not exceed 10t. The anchor cables are tensioned gradually, with each anchor cable pre-tensioned by 350t, and the four anchor cables pre-tensioned by a total of 1400t.

[0017] Preferably, in step S2, the cable anchor points are divided into front anchors and rear anchors, and the front anchor is a pre-tensioning anchor point, which is composed of tension-specific steel strands, front anchor lugs, and tensioning lifting devices. Two tensioning anchor points are set on each side of the bridge tower, and two tensioning lifting devices are used for each tensioning anchor point.

[0018] Preferably, in step S2, the auxiliary tower gantry column is made of P420x16 round tube, and the horizontal and diagonal web members are P180x6; the intermediate connecting truss crossbar is made of P273x10 round tube, and the horizontal and diagonal web members are P180x6.

[0019] (III) Beneficial Effects

[0020] This invention provides a method for vertically rotating the main tower of a single-tower, double-layer steel truss cable-stayed bridge, which has the following beneficial effects:

[0021] This invention, by assembling the main tower on the bridge deck, provides better construction conditions, makes welding quality easier to control, significantly shortens the main tower installation time, saves on temporary equipment investment, greatly reduces construction machinery costs, and makes structural safety easier to ensure. At the same time, the main tower structure is assembled at a 5° angle to the bridge deck, which makes it easier to pull than in a direct horizontal direction. Attached Figure Description

[0022] Figure 1This is a schematic diagram of the overall cross-section of the main tower vertical rotation in this invention;

[0023] Figure 2 This is a schematic diagram of the main tower in this invention undergoing trial vertical rotation;

[0024] Figure 3 This is a schematic diagram of the structure in this invention that uses tensioned anchor cables to perform a formal vertical rotation of the main tower;

[0025] Figure 4 This is a schematic diagram of the structure in this invention where tensioning the anchor cables causes the main tower to rotate vertically to 45°;

[0026] Figure 5 This is a schematic diagram of the structure in this invention where tensioning the anchor cables causes the main tower to rotate vertically to 60°;

[0027] Figure 6 This is a schematic diagram of the structure for pausing rotation traction and tensioning the back cable in this invention;

[0028] Figure 7 This is a schematic diagram of the structure in this invention where tensioning the anchor cables causes the main tower to rotate vertically to 75°;

[0029] Figure 8 This is a schematic diagram of the structure of the welding interface of the main tower, which is rotated vertically to 90° in this invention;

[0030] Figure 9 This is a schematic diagram of the structure for completing the main tower rotation by dismantling the rotating structure in this invention. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] like Figure 1-9 As shown, the present invention provides a technical solution: a method for vertically rotating the main tower of a single-tower double-layer steel truss cable-stayed bridge, characterized by comprising the following steps:

[0033] S1. A temporary assembly platform is set up on the bridge deck. The main tower structure is assembled at a 5° angle to the bridge deck, and the overall assembly is completed on the bridge deck.

[0034] S2. Assemble the secondary tower, install the two side cages, pressure rods, flexible tie rods, cable anchors, back cable anchors, steel strand jacks, etc., and install the secondary tower gantry on the main tower. Set the front anchor on the main tower and the rear anchor on the bridge deck.

[0035] S3. The steel strand traction cable and back cable are threaded with the steel strands. The steel strand traction cable and the steel strand tie rod are pre-tightened simultaneously. Each steel strand of the steel strand tie rod is pre-tightened by about 1t, and each steel strand is of equal length.

[0036] S4. Pay attention to the weather forecast in advance and make preparations before vertical rotation. Choose a windless day (or wind speed less than level 4) for vertical rotation.

[0037] S5. Pre-tension the anchor cables to make the secondary tower tensioned and form a stable triangular structure. Remove the pressure bar assembly support, then debug the steel strand jack synchronous vertical rotation system equipment, and then test the vertical rotation.

[0038] S6. The front end of the main tower detaches approximately 5cm from the assembly platform. Observe it statically for about one hour, checking the temporary vertical rotation structure, stabilizing cable system, vertical rotation system, foundation, lifting points, bottom hinge points, etc. Only after confirming that the entire vertical rotation process is absolutely safe can the formal vertical rotation begin.

[0039] S7. Use continuous steel strand jacks to gradually tension the anchor cables to make the main tower rotate vertically. While rotating vertically, monitor and control each structure. Rotate the main tower to 45°. During the rotation, closely monitor the tension of the traction cable. If the tension of a single steel strand is less than 4t, stop the rotation operation in time and report to the command personnel.

[0040] S8. When the main tower rotates to 60°, stop the rotation traction, then tension the back cable. When the main tower rotates to 75°, adjust the back cable to the specified tension.

[0041] S9. The main tower is rotated vertically to a position close to the design position. Measurement and control are performed to slow down the vertical rotation speed. The main tower is then finely adjusted in the vertical direction for precise positioning. The main tower interface is then welded, the rotating structure is dismantled, and the main tower rotation is completed.

[0042] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0043] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for vertically rotating the main tower of a single-tower, double-layer steel truss cable-stayed bridge, characterized in that, Includes the following steps: S1. A temporary assembly platform is set up on the bridge deck. The main tower structure is assembled at a 5° angle to the bridge deck, and the overall assembly is completed on the bridge deck. S2. Assemble the secondary tower, install the two side cages, pressure rods, flexible tie rods, cable anchors, back cable anchors, and steel strand jacks, and install the secondary tower gantry on the main tower. Set the front anchor on the main tower and the rear anchor on the bridge deck. S3. The steel strand traction cable and back cable are threaded with the steel strands. The steel strand traction cable and the steel strand tie rod are pre-tightened simultaneously. Each steel strand of the steel strand tie rod is pre-tightened by about 1t, and each steel strand is of equal length. S4. Pay attention to the weather forecast in advance and make preparations before the vertical turn. Choose a windless day to perform the vertical turn. S5. Pre-tension the anchor cables to make the secondary tower tensioned and form a stable triangular structure. Remove the pressure bar assembly support, then debug the steel strand jack synchronous vertical rotation system equipment, and then test the vertical rotation. S6. The front end of the main tower detaches from the assembly platform by approximately 5cm. Observe the stationary position for about one hour, checking the temporary vertical rotation structure, stabilizing cable system, vertical rotation system, foundation, lifting points, and bottom hinge points. Once the entire vertical rotation process is confirmed to be absolutely safe, the formal vertical rotation will begin. S7. Use continuous steel strand jacks to gradually tension the anchor cables to make the main tower rotate vertically. While rotating vertically, monitor and control each structure. Rotate the main tower to 45°. During the rotation, closely monitor the tension of the traction cable. If the tension of a single steel strand is less than 4t, stop the rotation operation in time and report to the command personnel. S8. When the main tower rotates to 60°, stop the rotation traction, then tension the back cable. When the main tower rotates to 75°, adjust the back cable to the specified tension. S9. The main tower is rotated vertically to a position close to the design position. Measurement and control are performed, the vertical rotation speed is slowed down, the main tower is finely adjusted in the vertical direction, and the position is accurately positioned. Then the main tower interface is welded, the rotating structure is removed, and the main tower rotation is completed. The pre-tensioned anchor cables are loaded step by step using continuous jacks, keeping them synchronized. The difference in pre-tension force between each jack cannot exceed 10t. The anchor cables are tensioned gradually, with each anchor cable pre-tensioned by 350t, and the four anchor cables pre-tensioned by a total of 1400t. In step S2, the cable anchor points are divided into front anchors and rear anchors. The front anchor is a pre-tensioning anchor point, which is composed of a special tensioning steel strand, a front anchor lug plate, and a tensioning hoist. Two tensioning anchor points are set on each side of the main tower, and two tensioning hoists are used for each tensioning anchor point. In step S2, the auxiliary tower gantry column is made of P420x16 round tube, and the horizontal and diagonal web members are P180x6.

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