Linear adjustment method of steel strand stay cable in replacement process

Abstract

The invention relates to a linear adjustment method for a steel strand stay cable in the replacement process, and belongs to the technical field of bridge maintenance construction. Comprising the steps of determining a current bridge surface line shape of the stayed cable of the cable-stayed bridge and a final target line shape of a bridge surface after the stayed cable of the cable- A finite element model is constructed, and the cable length variation corresponding to each stay cable of the cable-stayed bridge is calculated according to the current bridge deck line shape and the bridge deck final target line shape of the stay cables of the cable-stayed bridge; according to the cable length variation of the stay cable, the vertical deformation increment of the main beam corresponding to the cable length variation of the stay cable is calculated; after the cable force value of the stay cable is determined, the stay cable is dismantled, and the vertical deformation of the main beam before and after the stay cable is dismantled is obtained; according to the vertical deformation amount of the main beam of the stay cable, the vertical deformation increment of the main beam and the cable force value of the stay cable, the tension cable force value needed for achieving the target line shape after the stay cable is replaced is calculated; and according to the target tension cable force value, the target tension cable force value of each steel strand of the stay cable is calculated.

Description

Technical Field

[0001] The present application relates to the technical field of bridge maintenance and repair construction, and in particular to a method for adjusting the linear shape of a steel stranded cable during replacement. Background Art

[0002] Due to the objective influence of shrinkage creep, the main beam of a large-span concrete cable-stayed bridge will have obvious deflection after years of operation, which seriously affects the stress of the main beam structure and driving safety. As an important load-bearing component of a cable-stayed bridge, the cable has a design service life of about 20 to 30 years. After the cable reaches its design service life, it needs to be replaced. At present, the replacement of the cable is often based on the principle of equal replacement, that is, the cable with the same cable force is replaced first, and after the cable construction of the entire bridge is completed, the cable force of the new cable of the entire bridge is adjusted according to the requirements of the bridge deck line shape to achieve the target line shape.

[0003] The steel strand cable is composed of multiple strands of steel strands. During its replacement, single strands of steel strands are tensioned in batches one by one. The tensioning equipment uses small-tonnage jacks to meet the tensioning requirements of single strands of steel strands. However, after the construction of the entire bridge's cable-stayed cables is completed, the tension of the new cables of the entire bridge will be adjusted according to the requirements of the bridge deck line shape. The tension adjustment of the entire cable-stayed cable requires the use of large-tonnage jacks. The replacement of cable-stayed cables is different from the construction of new bridges. The replacement work space is limited, and it is difficult to install large-tonnage jack construction equipment. At the same time, the replacement construction requires the construction period to be shortened as much as possible and traffic operations to be resumed as soon as possible.

[0004] Therefore, it is necessary to design an adjustment method to adjust the bridge deck line shape of the steel strand cable during the construction process, and to achieve one-time tensioning construction. There is no need to use large-tonnage jacks to adjust the overall cable tension of the entire bridge, which solves the problem of limited construction space caused by the need to use large-tonnage jacks for construction layout, and helps to shorten the construction period. Summary of the invention

[0005] An embodiment of the present application provides a method for adjusting the linear shape of a steel strand cable during its replacement process, in order to solve the problem in the related art that, during the replacement process of the cable-stayed bridge cable, in order to ensure the linear shape of the bridge deck, a large-tonnage jack is required to be used to tension the replaced cable, which causes construction inconvenience and affects construction efficiency.

[0006] The embodiment of the present application provides a method for adjusting the linear shape of a steel stranded cable during replacement, comprising:

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

[0008] Construct a finite element model and calculate the length change of each cable of the cable-stayed bridge according to the current deck alignment of the cable-stayed bridge and the final target deck alignment;

[0009] According to the length change of the inclined cable, the vertical deformation increment of the main beam corresponding to the length change of the inclined cable is calculated;

[0010] After determining the cable force value of the inclined cable, remove the inclined cable and obtain the vertical deformation of the main beam before and after the inclined cable is removed;

[0011] According to the vertical deformation of the cable-stayed main beam, the vertical deformation increment of the main beam and the cable force value of the cable, the tensioning cable force value required for the cable to achieve the target line shape after replacement is calculated;

[0012] According to the target tensioning cable force value, the target tensioning cable force value of each steel strand of the inclined cable is calculated, and then the single steel strand is tensioned according to the cable force value, thereby completing the tensioning of the entire inclined cable.

[0013] In some embodiments, calculating the target tensioning force value of each steel strand of the inclined cable includes calculating the average tensioning control force of each steel strand according to the target tensioning force value of the inclined cable and the number of steel strands of the inclined cable;

[0014] According to the average tensioning control force of the steel strand, combined with the vertical deformation of the cable-stayed main beam, the vertical deformation increment of the main beam, the stress-free cable length of the cable between the cable tower end and the beam end anchor plate, the inclination angle of the cable beam section, the cross-sectional area and elastic modulus of each steel strand, the target tensioning force value of each steel strand is calculated.

[0015] In some embodiments, a casing is hung on the first steel strand and the second steel strand.

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

[0017] In some embodiments, when tensioning the steel strands, a jack is used to tension the steel strands.

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

[0019] In some embodiments, when a jack is used to tension the steel strands, the maximum output force of the jack does not exceed 150 kN.

[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 steel strand, tensioning is started from the third steel strand according to the target tensioning cable force value of the steel strand. After the tensioning of the remaining steel strands is completed, the first steel strand and the second steel strand are tensioned.

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

[0024] The embodiment of the present application provides a method for adjusting the linear shape of a steel stranded cable during replacement, comprising:

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

[0026] Construct a finite element model and calculate the length change of each cable of the cable-stayed bridge according to the current deck alignment of the cable-stayed bridge and the final target deck alignment;

[0027] According to the length change of the inclined cable, the vertical deformation increment of the main beam corresponding to the length change of the inclined cable is calculated;

[0028] After determining the cable force value of the inclined cable, remove the inclined cable and obtain the vertical deformation of the main beam before and after the inclined cable is removed;

[0029] According to the vertical deformation of the cable-stayed main beam, the vertical deformation increment of the main beam and the cable force value of the cable, the tensioning cable force value required for the cable to achieve the target line shape after replacement is calculated;

[0030] According to the target tensioning cable force value, the target tensioning cable force value of each steel strand of the inclined cable is calculated, and then the single steel strand is tensioned according to the cable force value, thereby completing the tensioning of the entire inclined cable.

[0031] In actual use, the data is determined first, and the current bridge deck alignment of the cable-stayed bridge is measured in detail using high-precision measuring equipment (such as total stations, laser rangefinders, etc.), and the coordinates and elevation data of key nodes are recorded. According to the bridge design documents and engineering requirements, the final target alignment of the bridge deck after the cable-stayed cable is replaced is determined, including the target coordinates and elevations of each key node. Then the 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 constructed. The model should accurately reflect the geometric shape, material properties, boundary conditions and initial cable force state of the cable-stayed cable. The finite element model is used for simulation analysis, and the cable length change required for each cable-stayed cable during the replacement process is calculated according to the current bridge deck alignment and the final target alignment. The vertical deformation increment of the main beam is then calculated: According to the cable length change of the cable, combined with the simulation results of the finite element model and the mechanical theory formula, the vertical deformation increment of the main beam corresponding to the cable length change is calculated. This step takes into account the interaction between the cable-stayed cable and the main beam and the stress characteristics of the overall bridge structure. Removal of the stay cable and measurement of deformation: After determining the cable force value of the stay cable, remove the target stay cable according to the construction plan. At the same time, use displacement sensors and other measuring equipment to accurately record the vertical deformation of the main beam before and after the removal of the stay cable. Calculate the target tensioning cable force value: Comprehensively consider the vertical deformation of the main beam of the stay cable, the vertical deformation increment of the main beam, and the cable force value of the stay cable (the initial cable force or reference design value can be set according to actual conditions), and calculate the tensioning cable force value required for the stay cable to achieve the target line shape after replacement through the mechanical equilibrium equation and deformation coordination conditions. Carry out tensioning construction of single-strand steel strands: According to the calculated target tensioning cable force value, combined with the number and specifications of the steel strands of the stay cable, calculate the target tensioning cable force value of each steel strand. This usually involves the consideration of parameters such as the cross-sectional area and elastic modulus of the steel strand. Using small jacks and other tensioning equipment, the steel strands are tensioned one by one according to the principle of first the middle and then the two sides (i.e., the third and subsequent strands are tensioned first, and the first and second strands are tensioned after they are stable to avoid excessive pressure on the casing), until the respective target tensioning cable force values ​​are reached. At the same time, by real-time monitoring of the vertical deformation of the main beam, the tensioning process is fine-tuned to ensure that the tensioning effect of the entire inclined cable meets expectations.

[0032] The construction adjustment method of this application considers adjusting the bridge deck line shape during the construction process. During the construction process, only small-tonnage jacks are needed for construction control, so that the tensioning construction is completed in one time. It is no longer necessary to adjust the overall cable force of the entire bridge. This can avoid the need to use large-tonnage jacks to tension the entire inclined cable in the traditional method, reducing the construction difficulty and risk. At the same time, the tensioning construction of single-strand steel strands is more flexible and convenient, which is conducive to shortening the construction period and resuming traffic operations, and can reduce the construction difficulty and risk. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0034] Figure 1 A flow chart of the method provided in the embodiment of the present application;

[0035] Figure 2 A schematic diagram of a cable-stayed bridge provided in an embodiment of the present application;

[0036] Figure 3 Schematic diagram of the steel strand and casing provided in the embodiment of the present application.

[0037] Reference numerals:

[0038] 1. Stay cable; 2. Casing; 11. Steel strand. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0040] The embodiment of the present application provides a method for adjusting the linear shape of a steel strand cable during its replacement process, which can solve the problem in the related art that, during the replacement process of the cable-stayed bridge cable, in order to ensure the linear shape of the bridge deck, it is necessary to use a large-tonnage jack to tension the replaced cable, which causes construction inconvenience and affects construction efficiency.

[0041] See also Figure 1 As shown, the embodiment of the present application provides a method for adjusting the linear shape of a steel stranded cable during replacement, comprising:

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

[0043] A finite element model is constructed, and the length change corresponding to each cable 1 of the cable-stayed bridge is calculated according to the current bridge deck alignment of the cable 1 of the cable-stayed bridge and the final target bridge deck alignment;

[0044] According to the length change of the inclined cable 1, the vertical deformation increment of the main beam corresponding to the length change of the inclined cable 1 is calculated;

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

[0046] According to the vertical deformation of the main beam of the inclined cable 1, the vertical deformation increment of the main beam and the cable force value of the inclined cable 1, the tensioning cable force value required for the inclined cable 1 to achieve the target line shape after replacement is calculated;

[0047] According to the target tensioning cable force value, the target tensioning cable force value of each steel strand 11 of the inclined cable 1 is calculated, and then the single steel strand 11 is tensioned according to the cable force value, thereby completing the tensioning of the entire inclined cable 1.

[0048] In actual use, data is first determined, and the current deck alignment of the cable-stayed bridge is measured in detail using high-precision measurement equipment (such as total stations, laser rangefinders, etc.), and the coordinates and elevation data of key nodes are recorded. According to the bridge design documents and engineering requirements, the final target alignment of the bridge deck after the replacement of the cable-stayed cable 1 is determined, including the target coordinates and elevations of each key node.

[0049] Then, the 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 constructed. The model should accurately reflect the geometric shape, material properties, boundary conditions and initial cable force state of the cable 1.

[0050] The finite element model is used for simulation analysis, and the cable length change required for each stay cable 1 during the replacement process is calculated according to the current bridge deck alignment and the final target alignment.

[0051] Then the vertical deformation increment of the main beam is calculated: according to the length change of the cable 1, combined with the simulation results of the finite element model and the mechanical theory formula, the vertical deformation increment of the main beam corresponding to the length change is calculated. This step takes into account the interaction between the cable 1 and the main beam and the stress characteristics of the overall bridge structure.

[0052] Removal of the cable 1 and measurement of deformation: After determining the cable force value of the cable 1, remove the target cable 1 according to the construction plan. At the same time, use displacement sensors and other measuring equipment to accurately record the vertical deformation of the main beam before and after the removal of the cable 1.

[0053] Calculate the target cable tension force: comprehensively consider the vertical deformation of the main beam of cable 1, the vertical deformation increment of the main beam and the cable force of cable 1 (the initial cable force or reference design value can be set according to actual conditions), and calculate the cable tension force required for achieving the target line shape of cable 1 after replacement through mechanical equilibrium equations and deformation coordination conditions.

[0054] Conduct tensioning construction of single strand steel strand 11: Calculate the target tensioning force value of each steel strand 11 based on the calculated target tensioning force value and the number and specification of the steel strand 11 of the inclined cable 1. This usually 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 are tensioned one by one according to the principle of first the middle and then the two sides (i.e., the third and subsequent strands 11 are tensioned first, and the first and second strands are tensioned after they are stable to avoid excessive pressure on the casing 2), until the respective target tensioning cable force values ​​are reached. At the same time, by real-time monitoring of the vertical deformation of the main beam, the tensioning process is fine-tuned to ensure that the tensioning effect of the entire inclined cable 1 meets expectations.

[0056] The construction adjustment method of the present application considers adjusting the bridge deck line shape during the construction process. During the construction process, only small-tonnage jacks are needed for construction control, so that the tensioning construction is completed in one time. It is no longer necessary to adjust the overall cable force of the entire bridge, which can avoid the situation in which large-tonnage jacks are needed to tension the entire inclined cable 1 in the traditional method, reducing the construction difficulty and risk. At the same time, the tensioning construction of the single-strand steel strand 11 is more flexible and convenient, which is conducive to shortening the construction period and resuming traffic operations, and can reduce the construction difficulty and risk.

[0057] In some optional embodiments, when calculating the target tensioning cable force value of each steel strand 11 of the inclined cable 1, the average tensioning control force of each steel strand 11 is calculated according to the target tensioning cable force value of the inclined cable 1 and the number of steel strands 11 of the inclined cable 1;

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

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

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

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

[0065] According to the target tensioning cable force value, the tensioning construction of a single steel strand inclined cable is carried out. Each steel strand inclined cable is composed of N steel strands 11. The first two steel strands 11 are used to bear the hanging of the HDPE sheath pipe 2. From the third steel strand 11, the single tensioning control starts. The control tensioning force of each steel strand 11 is determined by the coupling calculation of cable length and cable force. Until the tensioning of N steel strands 11 is completed, the first and second steel strands 11 are re-tensioned to complete the tensioning of the steel strand inclined cable.

[0066] In some optional embodiments, when the steel strand 11 is tensioned, a jack is used to tension the steel strand 11. The jack is a commonly used tensioning device, which has the characteristics of easy operation and high control accuracy. The use of the jack can achieve accurate tensioning of the steel strand 11, which helps to achieve a preset target tensioning cable force value.

[0067] In addition, the jack has a small size and weight, which is convenient for installation and use on the bridge site. In some optional embodiments, when the steel strand 11 is tensioned by the jack, the maximum output force of the jack does not exceed 150kN. Limiting the maximum output force of the jack can avoid damage to the steel strand 11 or the bridge structure due to excessive tensioning force. The output force limit of 150kN is a relatively reasonable range, which can not only meet the tensioning needs of most inclined cables 1, but also ensure safety during the construction process. In addition, the smaller output control force also helps to improve the accuracy and stability of tensioning.

[0068] Use small jacks and other tensioning equipment, and follow the principle of tensioning the middle first and then the two sides (i.e. tensioning the third and subsequent strands 11 first, and then tensioning the first and second strands after they are stable, so as to avoid excessive pressure on the casing 2), and tension the strands 11 one by one until their respective target tensioning cable force values ​​are reached. At the same time, by real-time monitoring of the vertical deformation of the main beam, the tensioning process is fine-tuned to ensure that the tensioning effect of the entire inclined cable 1 meets expectations. The construction adjustment method of the present application can calculate the required tensioning control force of each strand of steel strand 11, so that only a small tonnage jack is needed to implement the tensioning work. In actual use, the maximum output force of the jack does not exceed 150kN, which avoids the situation in which a large tonnage jack is needed to tension the entire inclined cable 1 in the traditional method, reducing the construction difficulty and risk. At the same time, the tensioning construction of a single strand of steel strand 11 is more flexible and convenient, which is conducive to shortening the construction period and resuming traffic operations, and can reduce the construction difficulty and risk.

[0069] In some optional embodiments, when tensioning the stay cables 1, the stay cables 1 on both sides of the main tower are tensioned simultaneously. Tensioning the stay cables 1 on both sides of the main tower simultaneously can maintain the symmetry of the bridge structure and reduce the structural distortion or imbalance caused by unilateral tensioning. This helps to ensure the overall stability and safety of the bridge during the replacement of the stay cables 1. At the same time, simultaneous tensioning can also improve construction efficiency and shorten the construction period.

[0070] In some optional embodiments, the vertical deformation increment of the main beam is measured by a displacement sensor. The displacement sensor can measure the vertical deformation increment of the main beam in real time and accurately, and provide reliable data support for calculating the target tensioning cable force value. Compared with traditional measurement methods, the displacement sensor has higher measurement accuracy and faster response speed, and can better meet the monitoring needs during the construction process. In some optional embodiments, the displacement sensor is arranged on the top of the main beam. Setting the displacement sensor on the top of the main beam can directly measure the vertical deformation of the main beam during the tensioning process of the inclined cable 1, avoiding errors caused by improper measurement position. In addition, the top of the main beam is usually the part where the structural deformation is most obvious. Setting the sensor here can more effectively monitor the deformation of the bridge.

[0071] In some optional embodiments, when tensioning a single strand of steel strand 11, tensioning is first started from the third strand of steel strand 11 according to the target tensioning cable force value of the steel strand 11, and after the tensioning of the remaining steel strands 11 is completed, the first strand of steel strand 11 and the second strand of steel strand 11 are tensioned. This tensioning sequence helps to reduce the pressure concentration phenomenon on the casing 2 and anchor of the inclined cable 1 during the tensioning process. Tensioning the middle strand (the third strand) first can balance the stress conditions of the steel strands 11 on both sides and avoid excessive local stress in the initial tensioning stage. After the tensioning of the middle strand is stable, tensioning the strands on both sides (the first strand and the second strand) can further ensure the stability and safety of the tensioning process. In addition, this tensioning sequence also helps to improve the tensioning efficiency and reduce the time and labor costs caused by repeated adjustments.

[0072] In actual use, Figures 1 to 3 As shown, the adjustment method of the present application can be applied to the replacement process of steel strand cables of 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 the three-tower cable-stayed bridge are the side main towers, the middle main tower, the main beam and the cable, and the cable type is a steel strand cable.

[0073] In this embodiment, it is determined that the final target alignment of the bridge deck after the cable stays of the three-tower cable-stayed bridge are replaced is that the maximum upward adjustment amount of the main beam mid-span is 100 mm, and the adjustment target alignment changes in a circular curve;

[0074] A finite element model is constructed, and the cable length change ΔS corresponding to each cable 1 of the cable-stayed bridge is calculated according to the current bridge deck alignment of the cable 1 of the cable-stayed bridge and the final target alignment of the bridge deck; taking the cable number MC23 as an example, the target alignment adjustment amount corresponding to the main beam position of the cable is 96 mm, and the corresponding cable length change ΔS=41.6 mm is calculated;

[0075] According to the cable length change ΔS of the inclined cable 1, the vertical deformation increment ΔD of the main beam corresponding to the cable length change ΔS of the inclined cable 1 is calculated; taking the inclined cable number MC23 as an example, according to the cable length change ΔS corresponding to the inclined cable number MC23 is 41.6mm, the vertical deformation increment ΔD of the main beam corresponding to the cable length change ΔS of the inclined cable is calculated to be 5.5mm;

[0076] After determining the cable force value of the inclined cable 1, remove the inclined cable 1, and obtain the vertical deformation ΔZ of the main beam before and after the inclined cable 1 is removed;

[0077] According to the vertical deformation ΔZ of the main beam of the inclined cable 1, the vertical deformation increment ΔD of the main beam and the cable force value F0 of the inclined cable 1, the tensioning cable force value Ft required for the inclined cable 1 to achieve the target line shape after replacement is calculated;

[0078] In this embodiment, taking the cable number MC23 as an example, the MC23 cable removal construction is carried out. Before removal, the cable force value F0=3724kN of the cable is obtained. The observation points of the bridge deck main beam are arranged, and the vertical deformation ΔZ=50.5mm of the main beam before and after the removal of the cable 1 is obtained. The formula Ft=F0×(ΔZ+ΔD) / ΔZ is used; the specific values ​​of each parameter are substituted, and the cable tension force value Ft required for the target line shape is obtained to be about 4129.6kN;

[0079] According to the target tensioning cable force value Ft, the target tensioning cable force value Fi of each steel strand 11 of the inclined cable 1 is calculated, and then the single steel strand 11 is tensioned according to the cable force value, thereby completing the tensioning of the entire inclined cable 1; in practice, according to the target tensioning cable force value Ft of the inclined cable and the number N of steel strands 11 of the inclined cable, the average tensioning control force Fp of each steel strand 11 is calculated; according to the average tensioning control force Fp of the steel strands 11, combined with the vertical deformation ΔZ of the main beam of the inclined cable, the vertical deformation increment ΔD of the main beam, the stress-free cable length S0 of the cable between the tower end of the inclined cable and the anchor pad at the beam end, the inclination angle α of the beam section of the inclined cable, the cross-sectional area A and the elastic modulus E of each steel strand 11, the target tensioning cable force value Fi of each steel strand 11 is calculated.

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

[0081] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present 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 only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0083] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for adjusting the linear shape of a steel stranded cable during replacement, characterized in that: include: Determine the current bridge deck alignment of the cable-stayed bridge cable (1) and the final target bridge deck alignment after the cable-stayed bridge cable (1) is replaced; A finite element model is constructed, and a cable length change corresponding to each cable (1) of the cable-stayed bridge is calculated according to the current bridge deck alignment of the cable (1) of the cable-stayed bridge and the final target bridge deck alignment; According to the length change of the inclined cable (1), the vertical deformation increment of the main beam corresponding to the length change of the inclined cable (1) is calculated; After determining the cable force value of the inclined cable (1), the inclined cable (1) is removed, and the vertical deformation of the main beam before and after the inclined cable (1) is removed is obtained; Calculate the tensioning force value required for the inclined cable (1) to achieve the target line shape after replacement according to the vertical deformation of the main beam of the inclined cable (1), the vertical deformation increment of the main beam and the cable force value of the inclined cable (1); According to the target tensioning cable force value, the target tensioning cable force value of each steel strand (11) of the inclined cable (1) is calculated, and then the single steel strand (11) is tensioned according to the cable force value, thereby completing the tensioning of the entire inclined cable (1).

2. A method for adjusting the linear shape of a steel stranded cable during replacement as claimed in claim 1, characterized in that: Calculate the target tension force of each strand of the cable, including: Calculating the average tension control force of each strand of the steel strand (11) according to the target tensioning force value of the inclined cable (1) and the number of steel strands (11) of the inclined cable (1); According to the average tension control force of the steel strand (11), combined with the vertical deformation of the main beam of the inclined cable (1), the vertical deformation increment of the main beam, the stress-free cable length of the cable between the tower end of the inclined cable (1) and the anchor pad at the beam end, the inclination angle of the beam section of the inclined cable (1), the cross-sectional area and elastic modulus of each strand of the steel strand (11), the target tension force value of each steel strand (11) is calculated.

3. The method for adjusting the linear shape of a steel stranded cable during replacement according to claim 1, characterized in that: Sleeves (2) are hung on the first strand of steel wire (11) and the second strand of steel wire (11).

4. The method for adjusting the linear shape of a steel stranded cable during replacement according to claim 3, characterized in that: The sleeve (2) is made of HDPE material.

5. The method for adjusting the linear shape of a steel stranded cable during replacement according to claim 1, characterized in that: When the steel strand (11) is tensioned, a jack is used to tension the steel strand (11).

6. The method for adjusting the linear shape of a steel stranded cable during replacement according to claim 1, characterized in that: When the inclined cables (1) are tensioned, the inclined cables (1) on both sides of the main tower are tensioned simultaneously.

7. The method for adjusting the linear shape of a steel stranded cable during replacement according to claim 5, characterized in that: When the steel strand (11) is tensioned by a jack, the maximum output force of the jack does not exceed 150 kN.

8. The method for adjusting the linear shape of a steel stranded cable during replacement according to claim 1, characterized in that: The vertical deformation increment of the main beam is measured by a displacement sensor.

9. A method for adjusting the linear shape of a steel stranded cable during replacement as claimed in claim 8, characterized in that: The displacement sensor is arranged on the top of the main beam.

10. The method for adjusting the linear shape of a steel stranded cable during replacement as claimed in claim 3, characterized in that: When tensioning a single steel strand (11), tensioning is first started from the third steel strand (11) according to the target tensioning cable force value of the steel strand (11), and after the tensioning of the remaining steel strands (11) is completed, the first steel strand (11) and the second steel strand (11) are tensioned.

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