Method for adjusting the line shape of a steel strand stay cable during replacement

Abstract

The application relates to a linear adjustment method for a steel strand cable in a replacement process, and belongs to the technical field of bridge maintenance and construction. The method comprises the following steps: determining the current bridge deck linear form of a cable-stayed bridge cable and the final target linear form of the bridge deck after the cable-stayed bridge cable is replaced; constructing a finite element model, and calculating the corresponding cable length change amount of each cable of the cable-stayed bridge according to the current bridge deck linear form of the cable-stayed bridge cable and the final target linear form of the bridge deck; calculating the corresponding main beam vertical deformation increment of the cable length change amount of the cable according to the cable length change amount of the cable; after the cable force value of the cable is determined, the cable is removed, and the vertical deformation amount of the main beam before and after the cable is removed is obtained; according to the vertical deformation amount of the main beam of the cable, the vertical deformation increment of the main beam and the cable force value, the target tension cable force value required by the cable after replacement to reach the target linear form is calculated; and according to the target tension cable force value, the target tension cable force value of each steel strand of the cable is calculated.

Description

Technical Field

[0001] This application relates to the field of bridge maintenance and construction technology, and in particular to a method for adjusting the alignment of a steel strand cable during the replacement process. Background Technology

[0002] Due to the inherent effects of shrinkage and creep, long-span concrete cable-stayed bridges often experience significant deflection of the main girder after many years of operation, severely impacting the structural stress and traffic safety. As crucial load-bearing components of cable-stayed bridges, the stay cables are designed for a service life of approximately 20 to 30 years. Once they reach their designed service life, cable replacement is necessary. Currently, the common replacement principle is equivalent substitution, meaning that cables with equal tension are first replaced. After the entire bridge's cable work is completed, the tension of the new cables is adjusted according to the bridge's alignment requirements to achieve the desired alignment.

[0003] A cable-stayed bridge is composed of multiple strands of steel wire. During replacement, individual strands are tensioned one by one, using small-tonnage jacks to meet the tensioning requirements of each strand. However, after the entire cable-stayed bridge is completed, the tension of all new cables needs to be adjusted according to the bridge deck alignment requirements. This adjustment requires large-tonnage jacks. Cable-stayed bridge replacement differs from new bridge construction in that the workspace is limited, and installing large-tonnage jacks is difficult. Simultaneously, the replacement work must be completed as quickly as possible to restore traffic operation.

[0004] Therefore, it is necessary to design an adjustment method to adjust the bridge deck alignment of the steel strand stay cables during construction, and to achieve tensioning in one go, eliminating the need to use large-tonnage jacks for overall cable force adjustment of the entire bridge. This would solve the problem of limited construction space caused by the need to use large-tonnage jacks for construction, and also help to shorten the construction period. Summary of the Invention

[0005] This application provides a method for adjusting the alignment of a steel strand cable during replacement, in order to solve the problem in related technologies where large-tonnage jacks are needed to tension the replacement cable to ensure the bridge deck alignment during cable replacement, which causes inconvenience and affects construction efficiency.

[0006] This application provides a method for adjusting the alignment of a steel strand stay cable during replacement, including:

[0007] Determine the current bridge deck alignment of the cable-stayed bridge and the final target bridge deck alignment after the cable-stayed bridge is replaced;

[0008] A finite element model is constructed, and the change in cable length for each cable of the cable-stayed bridge is calculated based on the current bridge deck alignment and the final target bridge deck alignment.

[0009] Based on the change in the length of the stay cable, calculate the vertical deformation increment of the main beam corresponding to the change in the length of the stay cable;

[0010] After determining the cable force value, the cable is removed, and the vertical deformation of the main beam before and after the removal of the cable is obtained.

[0011] Based on the vertical deformation of the main girder, the increment of vertical deformation of the main girder, and the cable force value of the cable, the required tension value of the cable after replacement to achieve the target alignment is calculated.

[0012] Based on the target tension value, the target tension value of each strand of the stay cable is calculated. Then, the tension of each strand is carried out according to the tension value, thereby completing the tensioning of the entire stay cable.

[0013] In some embodiments, calculating the target tension force of each strand of the stay cable includes calculating the average tension control force of each strand based on the target tension force of the stay cable and the number of strands of the stay cable.

[0014] Based on the average tension control force of the steel strands, combined with the vertical deformation of the main beam of the cable-stayed structure, the increment of the vertical deformation of the main beam, the stress-free cable length between the anchor plates at the tower end and the beam end of the cable-stayed structure, the inclination angle of the cable-stayed structure beam segment, the cross-sectional area and elastic modulus of each steel strand, the target tension cable force value of each steel strand is calculated.

[0015] In some embodiments, a sleeve is attached to the first and second steel strands.

[0016] In some embodiments, the sleeve is made of HDPE material.

[0017] In some embodiments, when tensioning the steel strand, jacks are used to tension the steel strand.

[0018] In some embodiments, when tensioning the stay cables, the stay cables on both sides of the main tower are tensioned simultaneously.

[0019] In some embodiments, when tensioning steel strands using jacks, the maximum output force of the jacks does not exceed 150kN.

[0020] In some embodiments, the vertical deformation increment of the main beam is measured by a displacement sensor.

[0021] In some embodiments, the displacement sensor is disposed on the top of the main beam.

[0022] In some embodiments, when tensioning a single strand of steel strand, tensioning is first initiated from the third strand according to the target tensioning force value of the steel strand. After the remaining steel strands are tensioned, the first and second strands are then tensioned.

[0023] The beneficial effects of the technical solution provided in this application include:

[0024] This application provides a method for adjusting the alignment of a steel strand stay cable during replacement, including:

[0025] Determine the current bridge deck alignment of the cable-stayed bridge and the final target bridge deck alignment after the cable-stayed bridge is replaced;

[0026] A finite element model is constructed, and the change in cable length for each cable of the cable-stayed bridge is calculated based on the current bridge deck alignment and the final target bridge deck alignment.

[0027] Based on the change in the length of the stay cable, calculate the vertical deformation increment of the main beam corresponding to the change in the length of the stay cable;

[0028] After determining the cable force value, the cable is removed, and the vertical deformation of the main beam before and after the removal of the cable is obtained.

[0029] Based on the vertical deformation of the main girder, the increment of vertical deformation of the main girder, and the cable force value of the cable, the required tension value of the cable after replacement to achieve the target alignment is calculated.

[0030] Based on the target tension value, the target tension value of each strand of the stay cable is calculated. Then, the tension of each strand is carried out according to the tension value, thereby completing the tensioning of the entire stay cable.

[0031] In practical application, the process begins with data determination. High-precision measuring equipment (such as total stations and laser rangefinders) is used to measure the current bridge deck alignment of the cable-stayed bridge in detail, recording the coordinates and elevation data of key nodes. Based on the bridge design documents and engineering requirements, the final target alignment of the bridge deck after the cable replacement is determined, including the target coordinates and elevations of each key node. Next, a finite element model is constructed: based on the structural characteristics and measurement data of the cable-stayed bridge, a high-precision finite element model is built. This model should accurately reflect the bridge's geometry, material properties, boundary conditions, and the initial cable force state of the cables. Simulation analysis is performed using the finite element model, calculating the required change in cable length for each cable during the replacement process based on the current bridge deck alignment and the final target alignment. Finally, the vertical deformation increment of the main girder is calculated: based on the change in cable length, combined with the simulation results of the finite element model and mechanical formulas, the corresponding vertical deformation increment of the main girder is calculated. This step considers the interaction between the cables and the main girder, as well as the stress characteristics of the overall bridge structure. Cable Removal and Deformation Measurement: After determining the cable force value, the target cable is removed according to the construction plan. Simultaneously, displacement sensors and other measuring equipment are used to accurately record the vertical deformation of the main beam before and after cable removal. Target Tension Force Calculation: Considering the vertical deformation of the main beam, the increase in vertical deformation, and the cable force value (initial force or reference design value can be set according to actual conditions), the required tension force value for the cable to achieve the target alignment after replacement is calculated using mechanical equilibrium equations and deformation compatibility conditions. Single-Strand Tensioning Construction: Based on the calculated target tension force value, and considering the number and specifications of the cable strands, the target tension force value for each strand is calculated. This typically involves considering parameters such as the cross-sectional area and modulus of elasticity of the strands. Using small jacks and other tensioning equipment, the steel strands are tensioned one by one, following the principle of tensioning the middle strands first and then the two outer strands (i.e., tensioning the third and subsequent strands first, and then the first and second strands after they have stabilized, to avoid putting excessive pressure on the sleeve). This continues until the target tension force is reached for each strand. Simultaneously, the vertical deformation of the main beam is monitored in real time, and fine adjustments are made to the tensioning process to ensure that the overall tensioning effect of the stay cable meets expectations.

[0032] The construction adjustment method proposed in this application considers adjusting the bridge deck alignment during construction. Only small-tonnage jacks are needed for construction control, achieving tensioning in a single step. This eliminates the need for overall cable tension adjustment across the entire bridge, avoiding the need for large-tonnage jacks to tension the entire stay cable in traditional methods, thus reducing construction difficulty and risk. Furthermore, the tensioning of single-strand steel cables is more flexible and convenient, which helps shorten the construction period and restore traffic operation, further reducing construction difficulty and risk. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 A flowchart illustrating the method provided in this application embodiment;

[0035] Figure 2 This is a schematic diagram of a cable-stayed bridge provided in an embodiment of this application;

[0036] Figure 3 This is a schematic diagram of the steel strand and sleeve provided in the embodiments of this application.

[0037] Figure label:

[0038] 1. Stay cable; 2. Sleeve; 11. Steel strand. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0040] This application provides a method for adjusting the alignment of a steel strand cable during replacement, which solves the problem in related technologies where large-tonnage jacks are needed to tension the replacement cable to ensure the bridge deck alignment during cable replacement, resulting in construction inconvenience and reduced construction efficiency.

[0041] See Figure 1 As shown in the embodiment of this application, a method for adjusting the alignment of a steel strand stay cable during replacement is provided, including:

[0042] Determine the current bridge deck alignment of cable-stayed bridge cable 1 and the final target bridge deck alignment after cable 1 is replaced;

[0043] A finite element model is constructed, and the change in cable length for each cable 1 is calculated based on the current bridge deck alignment and the final target bridge deck alignment of cable 1.

[0044] Based on the change in length of cable 1, the vertical deformation increment of the main beam corresponding to the change in length of cable 1 is calculated.

[0045] After determining the cable force value of cable 1, cable 1 is removed, and the vertical deformation of the main beam before and after the removal of cable 1 is obtained.

[0046] Based on the vertical deformation of the main beam of cable 1, the increment of vertical deformation of the main beam, and the cable force of cable 1, the tension cable force required for cable 1 to achieve the target alignment after replacement is calculated.

[0047] Based on the target tension value, the target tension value of each strand 11 of the stay cable 1 is calculated, and then the tension of each strand 11 is carried out according to the tension value, thereby completing the tensioning of the entire stay cable 1.

[0048] In practical use, data determination is first performed by using high-precision measuring equipment (such as total stations and laser rangefinders) to conduct detailed measurements of the current bridge deck alignment of the cable-stayed bridge, recording the coordinates and elevation data of key nodes. Based on the bridge design documents and engineering requirements, the final target alignment of the bridge deck after the replacement of cable 1 is determined, including the target coordinates and elevations of each key node.

[0049] Next, a finite element model is constructed: based on the structural characteristics and measurement data of the cable-stayed bridge, a high-precision finite element model is built. This model should accurately reflect the bridge's geometry, material properties, boundary conditions, and the initial cable force state of cable 1.

[0050] Using a finite element model for simulation analysis, the change in cable length required for each stay cable 1 during the replacement process is calculated based on the current bridge deck alignment and the final target alignment.

[0051] Next, the vertical deformation increment of the main beam is calculated: based on the change in cable length of cable 1, combined with the simulation results of the finite element model and mechanical theoretical formulas, the vertical deformation increment of the main beam corresponding to this change in cable length is calculated. This step takes into account the interaction between cable 1 and the main beam as well as the stress characteristics of the overall bridge structure.

[0052] Cable-stayed cable 1 removal and deformation measurement: After determining the cable force value of cable-stayed cable 1, the target cable-stayed cable 1 was removed according to the construction plan. At the same time, the vertical deformation of the main beam before and after the removal of cable-stayed cable 1 was accurately recorded using displacement sensors and other measuring equipment.

[0053] Calculate the target tension cable force value: Taking into account the vertical deformation of the main beam of cable 1, the increment of vertical deformation of the main beam, and the cable force value of cable 1 (the initial cable force or reference design value can be set according to the actual situation), calculate the tension cable force value required for cable 1 to achieve the target alignment after replacement through the mechanical equilibrium equation and deformation coordination conditions.

[0054] For single-strand steel strand 11 tensioning: Based on the calculated target tension force value, and combined with the number and specifications of the steel strands 11 in the stay cable 1, the target tension force value for each steel strand 11 is calculated. This typically involves consideration of parameters such as the cross-sectional area and elastic modulus of the steel strand 11.

[0055] Using small jacks and other tensioning equipment, the steel strands 11 were tensioned one by one, following the principle of tensioning the middle strands first and then the two outer strands (i.e., tensioning the third and subsequent strands 11 first, and then tensioning the first and second strands after they stabilize to avoid excessive pressure on the sleeve 2), until their respective target tension values ​​were reached. Simultaneously, the tensioning process was fine-tuned by monitoring the vertical deformation of the main beam in real time to ensure that the tensioning effect of the entire stay cable 1 met expectations.

[0056] The construction adjustment method proposed in this application considers adjusting the bridge deck alignment during construction. Only small-tonnage jacks are needed for construction control, achieving tensioning in a single step. This eliminates the need for overall cable tension adjustment across the entire bridge, avoiding the need for large-tonnage jacks to tension the entire stay cable 1 as in traditional methods, thus reducing construction difficulty and risk. Furthermore, the tensioning of single-strand steel cables 11 is more flexible and convenient, which helps shorten the construction period and restore traffic operation, further reducing construction difficulty and risk.

[0057] In some optional embodiments, when calculating the target tension force of each strand 11 of the stay cable 1, the average tension control force of each strand 11 is calculated based on the target tension force of the stay cable 1 and the number of strands 11 of the stay cable 1.

[0058] Based on the average tension control force of the steel strand 11, combined with the vertical deformation of the main beam of the cable 1, the increment of the vertical deformation of the main beam, the stress-free cable length between the anchor plate at the tower end and the beam end of the cable 1, the inclination angle of the cable 1 beam segment, the cross-sectional area and elastic modulus of each steel strand 11, the target tension cable force value of each steel strand 11 is calculated.

[0059] The parameters can be set as follows: the change in cable length of cable 1 is ΔS, the increase in vertical deformation of the main beam is ΔD; the vertical deformation of the main beam before and after the removal of cable 1 is ΔZ; the original cable force of cable 1 is F0; the target tension cable force of cable 1 is Ft; the average tension control force of steel strand 11 is Fp; the stress-free cable length between the anchor plate at the tower end and the beam end of cable 1 is S0; the inclination angle of the beam segment of cable 1 is α; the cross-sectional area of ​​each strand of steel strand 11 is A; the elastic modulus is E; the target tension cable force of steel strand 11 is Fi, and the number of steel strands 11 is N.

[0060] The calculation formula can be: Ft=F0×(ΔZ+ΔD) / ΔZ;

[0061] Fp = Ft / N;

[0062] Fi=Fp+(ΔZ+ΔD)×(Ni) / N]×sinα×E×A / S0, where i means the i-th strand of steel wire 11.

[0063] In some alternative embodiments, such as Figure 2 and Figure 3 As shown, sleeves 2 are hung on the first and second strands of steel wire 11.

[0064] In some alternative embodiments, the sleeve 2 is made of HDPE material.

[0065] Based on the target tension value, single-strand cable tensioning is carried out. Each cable consists of N strands of steel strands 11. The first two strands of steel strands 11 are used to support the HDPE sheath pipe 2. Starting from the third strand of steel strands 11, single-strand tensioning is controlled. The tension force of each strand of steel strands 11 is determined by the coupling calculation of cable length and cable force until the tensioning of N strands of steel strands 11 is completed. Then, the first and second strands of steel strands 11 are re-tensioned to complete the tensioning of the cable.

[0066] In some alternative embodiments, jacks are used to tension the steel strand 11. Jacks are commonly used tensioning equipment, characterized by ease of operation and high control precision. Using jacks allows for precise tensioning of the steel strand 11, helping to achieve the preset target tension force value.

[0067] Furthermore, the jacks are small in size and weight, facilitating installation and use on-site at bridge construction sites. In some alternative embodiments, when using the jacks to tension the steel strands 11, the maximum output force of the jacks does not exceed 150 kN. Limiting the maximum output force of the jacks can prevent damage to the steel strands 11 or the bridge structure due to excessive tension force. The 150 kN output force limit is a relatively reasonable range, meeting the tensioning requirements of most stay cables while ensuring safety during construction. In addition, the smaller output control force also helps to improve the accuracy and stability of tensioning.

[0068] Using small jacks and other tensioning equipment, the steel strands 11 are tensioned one by one, following the principle of tensioning the middle strands first and then the two outer strands (i.e., tensioning the third and subsequent steel strands 11 first, and then tensioning the first and second strands after they stabilize to avoid excessive pressure on the sleeve 2), until their respective target tension values ​​are reached. Simultaneously, the tensioning process is fine-tuned by real-time monitoring of the vertical deformation of the main beam to ensure that the tensioning effect of the entire stay cable 1 meets expectations. The construction adjustment method of this application can calculate the required tension control force for each steel strand 11, thus requiring only small-tonnage jacks for tensioning. In actual use, the maximum output force of the jacks does not exceed 150kN, avoiding the need for large-tonnage jacks to tension the entire stay cable 1 in traditional methods, reducing construction difficulty and risk. Furthermore, the tensioning of single steel strands 11 is more flexible and convenient, which helps to shorten the construction period and restore traffic operation, reducing construction difficulty and risk.

[0069] In some alternative embodiments, when tensioning the stay cables 1, the stay cables 1 on both sides of the main tower are tensioned simultaneously. Simultaneous tensioning of the stay cables 1 on both sides of the main tower maintains the symmetry of the bridge structure and reduces structural distortion or imbalance caused by unilateral tensioning. This helps ensure the overall stability and safety of the bridge during the replacement of the stay cables 1. Furthermore, simultaneous tensioning can improve construction efficiency and shorten the construction period.

[0070] In some optional embodiments, the vertical deformation increment of the main girder is measured using displacement sensors. Displacement sensors can measure the vertical deformation increment of the main girder in real time and accurately, providing reliable data support for calculating the target tension cable force value. Compared with traditional measurement methods, displacement sensors have higher measurement accuracy and faster response speed, better meeting the monitoring needs during construction. In some optional embodiments, the displacement sensors are installed at the top of the main girder. Placing the displacement sensors at the top of the main girder allows for direct measurement of the vertical deformation of the main girder during the tensioning process of the stay cable 1, avoiding errors caused by improper measurement location. Furthermore, the top of the main girder is usually the part where structural deformation is most pronounced; placing the sensor there allows for more effective monitoring of the bridge's deformation.

[0071] In some optional embodiments, when tensioning a single strand 11, tensioning begins with the third strand 11 according to the target tension value. After the remaining strands 11 are tensioned, the first and second strands 11 are then tensioned. This tensioning sequence helps reduce pressure concentration on the cable sleeve 2 and anchorage during the tensioning process. Tensioning the middle strand (third strand) first balances the stress on both sides of the strands 11, avoiding excessive local stress in the initial tensioning stage. After the middle strand is tensioned and stabilized, tensioning the two side strands (first and second strands) further ensures the smoothness and safety of the tensioning process. In addition, this tensioning sequence helps improve tensioning efficiency and reduces time and labor costs caused by repeated adjustments.

[0072] In practical use, such as Figures 1 to 3 As shown, the adjustment method of this application can be applied to the replacement process of steel strand cable stays in various cable-stayed bridges. Taking a three-tower concrete cable-stayed bridge with a double main span of 348m as an example, the span arrangement is 936m. A three-tower cable-stayed bridge refers to a cable-stayed bridge composed of three main towers, which are divided into two side main towers and one middle main tower structure. The main load-bearing components of a three-tower cable-stayed bridge are the side main towers, the middle main tower, the main beam and the cable stays, and the cable stay type is steel strand cable stays.

[0073] In this embodiment, the final target alignment of the bridge deck after the cable-stayed bridge is replaced is determined to be 100mm, which is the maximum upward adjustment amount at the mid-span of the main beam, and the target alignment is a circular curve.

[0074] A finite element model was constructed, and the change in cable length ΔS for each cable 1 was calculated based on the current bridge deck alignment and the final target alignment of the cable-stayed bridge. Taking cable 1 number MC23 as an example, the target alignment adjustment at the main beam position of this cable is 96mm, and the corresponding change in cable length ΔS = 41.6mm was calculated.

[0075] Based on the change in length ΔS of cable 1, the vertical deformation increment ΔD of the main beam corresponding to the change in length ΔS of cable 1 is calculated; taking cable number MC23 as an example, based on the change in length ΔS of cable number MC23 being 41.6mm, the vertical deformation increment ΔD of the main beam corresponding to the change in length ΔS of cable MC23 is calculated to be 5.5mm.

[0076] After determining the cable force value of cable 1, cable 1 is removed, and the vertical deformation ΔZ of the main beam before and after the removal of cable 1 is obtained.

[0077] Based on the vertical deformation ΔZ of the main beam of cable 1, the vertical deformation increment ΔD of the main beam, and the cable force F0 of cable 1, the tension cable force Ft required for cable 1 to achieve the target alignment after replacement is calculated.

[0078] In this embodiment, taking cable-stayed bridge number MC23 as an example, the cable-stayed bridge MC23 was dismantled. Before dismantling, the cable force value of the cable was obtained as F0 = 3724kN. Observation points were set up on the main beam of the bridge deck, and the vertical deformation of the main beam before and after the dismantling of cable-stayed bridge MC23 was obtained as ΔZ = 50.5mm. Using the formula Ft = F0 × (ΔZ + ΔD) / ΔZ, and substituting the specific values ​​of each parameter, the tension cable force value Ft required for the target alignment was obtained as approximately 4129.6kN.

[0079] Based on the target tension force Ft, the target tension force Fi of each strand 11 of the stay cable 1 is calculated. Then, the tension of each strand 11 is carried out according to the tension value, thereby completing the tensioning of the entire stay cable 1. In practice, based on the target tension force Ft of the stay cable and the number N strands 11 of the stay cable, the average tension control force Fp of each strand 11 is calculated. Based on the average tension control force Fp of the strand 11, combined with the vertical deformation ΔZ of the main beam of the stay cable, the vertical deformation increment ΔD of the main beam, the stress-free cable length S0 between the anchor plate at the tower end and the beam end of the stay cable, the inclination angle α of the stay cable beam segment, the cross-sectional area A and the elastic modulus E of each strand 11, the target tension force Fi of each strand 11 is calculated.

[0080] In this embodiment, taking cable-stayed cable number MC23 as an example, this cable-stayed cable is composed of 47 steel strands 11. Therefore, the value of N is 47. Based on the target tension force Ft of the cable-stayed cable and the number of steel strands 11 N, the average tension control force Fp of each steel strand 11 is calculated. Using the formula Fp=Ft / N, substituting the specific parameter values, Fp is found to be approximately 87.86kN. According to the design drawings and other data, the stress-free cable length S0 between the anchor plate at the tower end and the beam end of cable-stayed cable MC23 is 207.164m, the inclination angle α at the beam end of the cable-stayed cable is 25°, and the calculated cross-sectional area A of each steel strand 11 is 140mm². 2 With an elastic modulus E of 195000MPa, according to the formula Fi=Fp+(ΔZ+ΔD)×(Ni) / N]×sinα×E×A / S0, the control tension of the third strand 11 of the MC23 cable (the third strand 11 is calculated here, so i is 3) is approximately 104.21kN. Then, the target tension value Fi of each strand 11 can be calculated according to the formula, and each strand 11 is tensioned into place according to the target tension value of each strand 11. In this way, using small-tonnage jacks can ensure good adjustment of the bridge deck alignment when replacing the cable, avoiding the use of large-tonnage jacks to tension the entire cable, improving construction efficiency and reducing construction difficulty.

[0081] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0082] It should be noted that in this application, relational terms such as "first" and "second" are used merely 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 a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0083] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for adjusting the alignment of a steel strand stay cable during replacement, characterized in that, include: Determine the current bridge deck alignment of the cable-stayed bridge (1) and the final target bridge deck alignment after the cable-stayed bridge (1) is replaced; A finite element model was constructed, and the change in cable length of each cable (1) of the cable-stayed bridge was calculated based on the current bridge deck alignment and the final target bridge deck alignment of the cable-stayed bridge (1). Based on the change in length of the cable (1), the vertical deformation increment of the main beam corresponding to the change in length of the cable (1) is calculated. After determining the cable force value of the stay cable (1), the stay cable (1) is removed, and the vertical deformation of the main beam before and after the removal of the stay cable (1) is obtained. Based on the vertical deformation of the main beam of the cable (1), the increment of the vertical deformation of the main beam, and the cable force of the cable (1), the tension cable force required for the cable (1) to achieve the target alignment after replacement is calculated. Based on the target tension value, the target tension value of each strand (11) of the stay cable (1) is calculated, and then the tension of each strand (11) is carried out according to the tension value, thereby completing the tension of the entire stay cable (1). Calculate the target tension force of each strand of the stay cable, including: Based on the target tension force of the cable (1) and the number of steel strands (11) of the cable (1), the average tension control force of each steel strand (11) is calculated. Based on the average tension control force of the steel strands (11), combined with the vertical deformation of the main beam of the cable (1), the increment of the vertical deformation of the main beam, the stress-free cable length between the anchor plates at the tower end and the beam end of the cable (1), the inclination angle of the cable (1) beam segment, the cross-sectional area and elastic modulus of each steel strand (11), the target tension cable force value of each steel strand (11) is calculated.

2. The method for adjusting the alignment of a steel strand cable during replacement as described in claim 1, characterized in that: A sleeve (2) is hung on the first strand (11) and the second strand (11).

3. The method for adjusting the alignment of a steel strand cable during replacement as described in claim 2, characterized in that: The sleeve (2) is made of HDPE material.

4. The method for adjusting the alignment of a steel strand cable during replacement as described in claim 1, characterized in that: When tensioning the steel strand (11), jacks are used to tension the steel strand (11).

5. The method for adjusting the alignment of a steel strand cable during replacement as described in claim 1, characterized in that: When tensioning the stay cables (1), tensioning is carried out simultaneously on both sides of the main tower.

6. The method for adjusting the alignment of a steel strand cable during replacement as described in claim 4, characterized in that: When using a jack to tension the steel strand (11), the maximum output force of the jack shall not exceed 150kN.

7. The method for adjusting the alignment of a steel strand cable during replacement as described in claim 1, characterized in that: The vertical deformation increment of the main beam is measured by a displacement sensor.

8. The method for adjusting the alignment of a steel strand cable during replacement as described in claim 7, characterized in that: The displacement sensor is located on the top of the main beam.

9. The method for adjusting the alignment of a steel strand cable during replacement as described in claim 2, characterized in that: When tensioning a single strand of steel strand (11), tensioning is first initiated from the third strand of steel strand (11) according to the target tension value of the steel strand (11). After the remaining steel strands (11) are tensioned, the first strand of steel strand (11) and the second strand of steel strand (11) are tensioned.

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