Steel strand buckle cable tensioning control method
By marking the stress-free length on the steel strand, the problem of uneven tensioning of the steel strand in the existing technology is solved, and uniform tensioning of the steel strand cable is achieved, thus improving construction efficiency.
Patent Information
- Application Number
- CN202511175447.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-21
- Publication Date
- 2025-11-14
AI Technical Summary
Existing technologies cannot accurately control the uniformity of steel strands during the tensioning process of arch bridge cables, resulting in long construction cycles and significant influence from the environment and operators, making it impossible to achieve uniform tensioning.
The theoretical stress-free length of the steel strand to be constructed is calculated based on the finite element model, and stress-free length markers are marked on the steel strand. The stress-free length of the markers is calculated using the linearity and force between the tensioning structure and the anchoring structure to ensure that each steel strand is in a stress-free state during installation.
This ensured the accuracy and uniformity of steel strand tensioning, improved construction efficiency, and guaranteed the overall synchronous tensioning operation of the steel strand ties.
Smart Images
Figure CN120945796A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of bridge steel strand tensioning technology, specifically to a method for controlling the tensioning of steel strand cables. Background Technology
[0002] Cable tensioning technology for arch bridges is a core process in the construction of arch bridges without scaffolding. It is mainly used for temporary or permanent support and internal force adjustment of the arch ribs during cantilever assembly or segmented construction. Its core objective is to ensure that the arch rib alignment meets design requirements by precisely controlling the tension of the cables, while optimizing the distribution of internal forces in the structure to ensure construction safety and the stability of the completed bridge.
[0003] For example, an existing technology entitled "A Method for Controlling the Tension of a Single Steel Strand in a Cable-Stayed Cable-Connected System" proposes a method for controlling the tension of a steel strand. Specifically, the method involves: S1, installing and pre-tightening each steel strand in the cable-stayed cable and anchor cable, with a pre-tightening force of F, and measuring the elevation H0 of the front end of the main arch of the bridge after pre-tightening; S2, establishing a finite element model of the bridge's tensioning process, pre-tightening the cable-stayed cable and anchor cable in the finite element model using the same pre-tightening force F, and calculating the theoretical elevation H′0 of the front end of the main arch after pre-tightening; S3, ... In the finite element model of the tensioning process, the tie cable and anchor cable are tensioned with 100% design cable force. The theoretical elevation H of the front end of the main arch after tensioning is calculated, and the theoretical elevation change of the front end of the main arch after tensioning with 100% design cable force is ΔH = HH′0. Let i = 1, and the theoretical sequence force of the i-th tensioning of each strand of the tie cable and anchor cable is calculated from the finite element model during the tensioning process. S4, the tie cable and anchor cable are tensioned according to the theoretical sequence force of the i-th tensioning. S5, the actual height H of the front end of the main arch after the i-th tensioning is measured. i S6, Calculation error δ i =(△H-△H) i ) / △H, where △H i =H i -H0, △H i Let δ be the actual change in height at the front end of the main arch after the i-th tensioning; determine δ i Check if the error requirement is met. If it is, the tensioning is in place; if not, proceed to step S7. S7: Based on δ... iThe finite element model of the tensioning process is modified by setting i = i + 1 and recalculating the theoretical sequence force for the i-th tensioning. Steps S4 to S6 are repeated. This method modifies the finite element model of the tensioning process through multiple tensioning operations, using the deviation between the measured elevation change and the theoretical change as a benchmark. The theoretical tensioning force is adjusted so that the final elevation rise is close to the theoretical change. During the process of multiple tensioning operations to approximate the theoretical change, the cable forces also tend to be uniform, thereby achieving stress-free closure of the main arch. However, this method can only control the preload to be the same, but cannot control the uniformity of the entire cable tensioning. Due to the large number and length of the cable strands, the construction period is long, and the tension and uniformity of the strands are greatly affected by environmental factors such as sunlight and wind, as well as the operators. To control the uniformity of cable tensioning, it is necessary to obtain the stress-free length of the strands. Although this stress-free length can be calculated using a finite element model, the calculated value is theoretical and cannot be accurately marked on the strands to be tensioned (the strands are bent after cutting and need to be stretched to straighten. However, the strands after stretching are not in a stress-free state, so the length of the strands in the stress-free state cannot be accurately obtained). This results in different strands experiencing completely different forces during the cable tensioning process, failing to achieve the goal of uniform tensioning, and making it impossible to determine the tension value after tensioning. Summary of the Invention
[0004] The purpose of this application is to address the shortcomings of the aforementioned background technology and provide a method for controlling the tension of steel strands.
[0005] The technical solution of this application is: a method for controlling the tension of steel strand cable, comprising, The theoretical stress-free length of the steel strand to be constructed was calculated based on the finite element model. Connect one end of the steel strand to be constructed to the anchoring structure and the other end to the tensioning structure. Based on the tensioning structure, a set tension force is applied to the steel strand to be constructed. The stress-free length of the steel strand to be constructed under the current state is calculated according to the shape of the steel strand to be constructed between the tensioning structure and the anchoring structure and the tensioning force. Mark the steel strands to be constructed according to the calculated stress-free length of the ruler to form stress-free length marking points; Based on the theoretical stress-free length and the scale stress-free length marking points, mark the theoretical stress-free length marking points on the steel strand to be constructed; Tensioning is carried out on the steel strands to be constructed according to the theoretical stress-free length marking points.
[0006] According to the tension control method for steel strand cable provided in this application, the method for calculating the stress-free length of the scale includes... Calculate the stress-free length of the scale using the following formula. in: S —The stress-free length of the steel strand to be constructed; S 1 —The stress-free length of a single catenary formed when the steel strand to be constructed is tensioned in the tensioning structure; S 2 —The stress-free length of the straight section formed when the steel strand to be constructed is tensioned in the tensioning structure; L 1 —The horizontal length of a single catenary formed when the steel strand to be constructed is tensioned in the tensioning structure; L 2 —The horizontal length of the straight section formed when the steel strand to be constructed is tensioned in the tensioning structure; F —The tensile force applied to the steel strands to be constructed in a tensioned structure; E —The elastic modulus of the steel strand to be constructed; A —The cross-sectional area of the steel strand to be constructed; l —The horizontal distance between a point on the catenary formed by the steel strand to be constructed during tensioning of the tensioning structure and the anchoring point connecting the anchoring structure and the steel strand to be constructed, or the horizontal distance between a point on the catenary formed by the steel strand to be constructed during tensioning of the tensioning structure and the anchoring point connecting the tensioning structure and the steel strand to be constructed. a、a 1 —Parameters of the catenary equation; q —Intensity of self-weight load of the steel strands to be constructed; x —The horizontal distance between a point on the steel strand to be constructed and the anchorage point connecting the tensioning structure and the steel strand to be constructed; y —The distance from a point on the steel strand to be constructed to the horizontal plane, where the horizontal plane refers to the horizontal plane at the bottom of the anchoring structure and tensioning structure; c — A coefficient related to the horizontal force and self-weight load intensity of the steel strand to be constructed; H — Horizontal force on the steel strand.
[0007] According to the steel strand tensioning control method provided in this application, the method of connecting one end of the steel strand to be constructed to the anchoring structure and the other end to the tensioning structure includes: fixing one end of the steel strand to be constructed to the anchoring base anchored on the horizontal plane, and the end of the steel strand to be constructed passing through the crossbeam on the anchoring base and fixing it to the anchoring base; passing the other end of the steel strand to be constructed through the tensioning base anchored on the horizontal plane, and the other end of the steel strand to be constructed passing through the tensioning jack on the tensioning base and installing the anchor cable gauge.
[0008] According to the tension control method for steel strands provided in this application, the method of applying a set tension force to the steel strand to be constructed based on the tensioning structure includes: applying a tension force to the steel strand to be constructed so that the difference between the calculated stress-free length on the scale and the theoretical stress-free length after the steel strand to be constructed is within a set range.
[0009] According to the tension control method for steel strand cable provided in this application, the setting range is ±0.5m.
[0010] According to the tension control method for steel strands provided in this application, the method of marking the steel strand to be constructed according to the calculated stress-free length to form stress-free length marker points includes: after calculating the stress-free length, taking the connection point between the steel strand to be constructed and the anchoring structure as the starting point of the marking, and forming stress-free length marker points on the steel strand to be constructed according to the calculated stress-free length.
[0011] According to the tension control method for steel strands provided in this application, the method of marking the theoretical stress-free length mark point on the steel strand to be constructed based on the theoretical stress-free length and the scale stress-free length mark point includes: calculating the difference between the theoretical stress-free length and the scale stress-free length, and marking the steel strand to be constructed after the tension is removed according to the difference and the stress-free length mark point to form the theoretical stress-free length mark point.
[0012] According to the tension control method for steel strand cable provided in this application, after marking the theoretical stress-free length mark point on the steel strand to be constructed, multiple mark points are marked on both sides of the theoretical stress-free length mark point at a set interval, with the theoretical stress-free length mark point as the center.
[0013] According to the tension control method for steel strand cable provided in this application, the set interval is 0.02m~0.03m.
[0014] According to the tensioning control method for steel strands provided in this application, the method of tensioning the steel strands to be constructed according to the theoretical stress-free length marker points includes: installing the marked starting point on the steel strands to be constructed to the tower end anchor point, installing the theoretical stress-free length marker points on the steel strands to be constructed to the beam segment, and using the jacks of the beam segment to tension the steel strands to be constructed step by step to the set cable force.
[0015] The advantages of this application are as follows: 1. Based on the theory of multi-segment catenary scale steel strands, this application proposes a method for controlling the tension of scale steel strands. By controlling the stress-free length of each steel strand, the tension and uniformity of the cable strands are guaranteed. By accurately marking the stress-free length of the steel strands, the tension of the cable strands is controlled, ensuring that each steel strand is in a standard stress-free state when installed on the tower end and beam segment. This facilitates subsequent overall synchronous tensioning operations, ensures the accuracy and uniformity of the steel strand tensioning, and improves the efficiency of the cable strand tensioning. 2. This application proposes a method for calculating the stress-free length of a scale under tension. Based on this calculation method, the stress-free length of the steel strand to be constructed can be quickly determined under actual conditions by constructing the theoretical catenary scale steel strand. Based on the determined stress-free length of the scale, the theoretical stress-free length can be marked on the steel strand to be constructed. The marked theoretical stress-free length has a practical test basis, and the marking result can reflect the actual situation of the steel strand to be constructed, making the marking result more accurate. 3. This application constructs a device specifically designed for conducting tension tests on steel strands. This device can perform tension tests on the steel strands to be constructed, enabling the steel strands to be constructed to form a catenary structure that is easy to calculate and analyze, thus facilitating operation. 4. In the process of tensioning the steel strand to be constructed, this application controls the tension to ensure that the steel strand to be constructed can form the required structure that is easy to calculate and analyze. On the other hand, if the tension is too large, the anchoring clips will cause greater damage to the steel strand. 5. This application limits the set range to ensure that the final determined stress-free length of the scale is close to the theoretical stress-free length, so as not to cause inaccurate marking due to excessive difference, thereby improving the accuracy of subsequent construction. 6. The method for marking stress-free markers on the scale in this application is very simple. By taking the anchor point of the anchoring structure as the starting point and the calculated stress-free length of the scale as the marking distance, the required stress-free markers on the scale can be obtained quickly. The marking is rapid and easy to operate. 7. This application determines the theoretical stress-free length marker point by the difference between the theoretical stress-free length and the scale stress-free length. The theoretical stress-free length marker point is constructed based on the scale stress-free marker point, and its authenticity has been verified. The determination of the theoretical stress-free length marker point is very accurate. 8. After determining the theoretical stress-free length marker point, this application will construct other equally spaced marker points with the theoretical stress-free length marker point as the midpoint. These marker points can facilitate tension adjustment during subsequent actual cable installation and ensure the uniformity of subsequent tension control. 9. This application has determined the set interval. 0.02m~0.03m is a suitable interval distance. It is not too large, which will cause the problem of unevenness. It is not too small, which will make it difficult to mark and adjust. This greatly improves the convenience of subsequent steel strand tensioning and installation. 10. This application uses theoretical stress-free length markers to install steel strands, which ensures that the steel strands installed between the tower end and the beam segment are in a stress-free state. This greatly facilitates the subsequent tensioning control of the steel strands and ensures the accuracy and uniformity of the tensioning.
[0016] The tensioning control method for steel strand cables in this application is simple and can accurately determine the theoretical stress-free length, ensuring the accuracy and uniformity of the steel strand cables during tensioning and installation. This greatly facilitates subsequent overall synchronous tensioning operations and improves the efficiency of steel strand cable tensioning. Attached Figure Description
[0017] Figure 1 : A schematic diagram of the steel strand cutting length in this application; Figure 2 This application presents a schematic diagram of the steel strand to be constructed under tension in a tensioning structure. Detailed Implementation
[0018] The embodiments of this application are described in detail below, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.
[0019] In the description of this application, it should be understood that the terms "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They 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. Therefore, they should not be construed as limitations on this application.
[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0021] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.
[0022] This application relates to a method for controlling the tension of steel strand cables. The main aspect of this method is to propose an accurate way to identify the theoretical stress-free length of the steel strand. Currently, calculating the theoretical stress-free length of the steel strand using a finite element model is not problematic. However, how to accurately identify this theoretical stress-free length on the actual steel strand is unknown. During actual construction, the steel strand is affected by factors such as transportation methods and its own tension, causing it to bend under stress-free conditions, making it impossible to accurately determine the true theoretical stress-free length. Applying a certain tension to the steel strand can indeed straighten it, but this alters its stress-free state, stretching it along its length. Even if the calculated theoretical stress-free length is used for identification, the result will not be the true theoretical stress-free length.
[0023] This application constructs a dedicated equipment structure for testing steel strands under construction. By applying a length-direction tension to the steel strands, the process forces them into a linear structure suitable for calculation and analysis. The stress-free length of the steel strands under the current tension is then calculated and marked accordingly. Based on this marked stress-free length, the theoretical stress-free length can be marked. This method allows for the accurate and valid marking of the theoretical stress-free length on the steel strands under construction. Based on this marked theoretical stress-free length, tension control can be implemented during the actual tensioning of the steel strands, ensuring that all steel strands are initially stress-free, allowing for uniform subsequent tensioning.
[0024] Specifically, the tension control method for steel strand cable of this application is carried out according to the following steps: S1. Calculate the theoretical stress-free length of the steel strand to be constructed based on the finite element model; Before cutting, the steel strands are checked to ensure that the cutting length meets the requirements for anchoring, tensioning, marking, and stress-free cable length. Figure 1 As shown, the cutting length of the steel strand is... L The calculation formula is as follows: in: L—Steel strand cutting length, in meters; L u —Theoretical stress-free length of steel strand, in meters; L TM — Anchorage length at the tower end of the steel strand, in meters; L Z — Working length for tensioning the steel strand beam end, in meters; L T —Elongation of the steel strand during tensioning, in meters; Calculate the cutting length of steel strand L The goal is to obtain a suitable length of steel strand for construction, where the theoretical stress-free length of the steel strand is... L u The anchorage length at the tower end of the steel strand is obtained through calculation using a finite element model. L TM The working length of the steel strand beam end tensioning is determined by the dimensions and specifications of the tower end anchoring structure. L Z It is determined based on the dimensions and specifications of the beam end tensioning equipment structure; the elongation during the tensioning of the steel strands. L T Calculated from the anchoring force at the beam end; S2. Connect one end of the steel strand to be constructed to the anchoring structure and the other end to the tensioning structure. Specifically, the anchoring structure of this application includes an anchoring base, such as... Figure 2 As shown, the anchoring base is anchored to the horizontal plane (which can be the bridge deck for the steel strands to be constructed) by bolts. An anchoring beams arranged laterally are installed on the anchoring base. The anchoring beams are I-beam structures with multiple through holes (allowing for the simultaneous installation of multiple steel strands and enabling tensioning of multiple strands, significantly improving efficiency). One end of the steel strand to be constructed can pass through the through holes and be anchored to the anchoring beams using nuts or other structures. The tensioning structure also includes a tensioning base, which is also anchored to the horizontal plane by bolts. A tensioning beam arranged laterally is installed on the tensioning base. The tensioning beam is an I-beam structure with multiple through holes, through which one end of the steel strand to be constructed can pass. A tensioning jack is located on the opposite side of the tensioning beam, through which the steel strand to be constructed passes and connects to the tensioning jack. The tensioning structure also includes an anchor gauge for measuring tension. In practical applications, the two ends of the steel strand to be constructed are connected to the anchoring structure and the tensioning structure, respectively. S3. Apply a set tension force to the steel strand to be constructed based on the tensioning structure, and calculate the stress-free length of the steel strand to be constructed under the current state according to the shape of the steel strand to be constructed between the tensioning structure and the anchoring structure and the tensioning force. The tension is applied to the steel strand to be constructed by tensioning jacks. The purpose of applying tension to the steel strand to be constructed is to prevent the steel strand to be constructed from being in a slack state when marking. By applying tension to the steel strand to be constructed, it is made to get out of a slack state or out of a coiled state, so as to ensure that the marking points are accurate. The applied tension is subject to requirements and cannot be applied arbitrarily. Firstly, it must be ensured that the steel strand to be installed can fully extend without curling. Secondly, the strand's alignment between the anchoring base and the tensioning base must be such that both ends are catenary sections, with a straight section in the middle. Figure 2 As shown, further, the difference between the calculated stress-free length on the scale and the theoretical stress-free length after the steel strand to be constructed is tensioned is within a set range. The set range of this application is ±0.5m, that is, the difference between the theoretical stress-free length and the stress-free length on the scale is within ±0.5m. After tension is applied to the steel strand to be constructed, the steel strand to be constructed forms a catenary-shaped structure between the anchoring base and the tensioning base, as shown in the following details. Figure 2 As shown, because the tension applied to the steel strand to be constructed in this application is not to fully tension the steel strand to be constructed, the middle part of the steel strand to be constructed hangs down naturally and contacts the ground, forming a line shape with catenary structure at both ends and straight section structure in the middle. At this time, the stress-free length under the current state can be calculated based on the catenary theory, that is, the stress-free length of the scale. S4. Mark the steel strands to be constructed according to the calculated stress-free length on the ruler to form stress-free length marking points; After calculating the stress-free length of the steel strand to be constructed, the steel strand to be constructed can be marked based on the calculated stress-free length. The marked stress-free length markers are the basis for subsequent marking of theoretical stress-free length markers. S5. Mark the theoretical stress-free length on the steel strand to be constructed based on the theoretical stress-free length and the scale stress-free length marking points. In practical applications, the stress-free length of the scale is intentionally controlled to be close to the theoretical stress-free length. On the one hand, if the difference between the two is too large, the distance between the theoretical stress-free length mark and the stress-free length mark on the scale will be too large when marking the theoretical stress-free length mark. The steel strands between the two may be bent and difficult to mark accurately. On the other hand, a large difference between the two can also easily cause marking errors. S6. Tension the steel strands to be constructed according to the theoretical stress-free length marking points. Once the theoretical stress-free length marker point of the steel strand to be constructed is obtained, the steel strand to be constructed can be installed using this theoretical stress-free length marker point. Under normal circumstances, the point corresponding to the theoretical stress-free length marker point is closer to the beam end. After installation according to the theoretical stress-free length marker point, the length of the steel strand between the tower end and the beam segment is considered to be the stress-free length. Then, tensioning to the design cable force according to the set requirements can ensure that the installation of all steel strand cables is uniform.
[0025] This application ensures that each steel strand is in a stress-free state during the initial installation of the steel strands, and that the subsequent tensioning is controllable. By controlling the tension of each steel strand, the tensioning of the steel strands can be uniformly controlled.
[0026] In some embodiments of this application, step S3 described above has been optimized. Specifically, the method for calculating the stress-free length of the scale is as follows: like Figure 2 As shown, calculate the stress-free length of the scale using the following formula. in: S —The stress-free length of the steel strand to be constructed, in meters; S 1 —The stress-free length of a single catenary formed by the steel strand to be constructed during the tensioning of the tensioning structure, in meters; S 2 —The stress-free length of the straight section formed by the steel strand to be constructed during the tensioning of the tensioning structure, in meters; L 1 — The horizontal length of a single catenary formed by the steel strand to be constructed during the tensioning of the tensioning structure, in meters; L 2 — The horizontal length of the straight section formed by the steel strand to be constructed during the tensioning of the tensioning structure, in meters; F —The tensile force applied to the steel strands to be constructed in the tensioned structure, in kN; E —The elastic modulus of the steel strand to be constructed, in MPa; A —Cross-sectional area of the steel strand to be constructed, in m² 2 ; l— The horizontal distance, in meters, between a point on the catenary formed by the steel strand to be constructed during tensioning of the tensioning structure and the anchoring point connecting the anchoring structure and the steel strand to be constructed. a、a 1 —Parameters of the catenary equation; q —Self-weight load intensity of the steel strand to be constructed, kN / m; x — The horizontal distance, in meters, between a point on the steel strand to be constructed and the anchorage point connecting the tensioning structure and the steel strand to be constructed; y —The distance from a point on the steel strand to be constructed to the horizontal plane, where the horizontal plane refers to the horizontal plane at the bottom of the anchoring structure and tensioning structure, in meters; c —A coefficient related to the horizontal force and self-weight load intensity of the steel strand to be constructed, in meters. c=H / q ; H — Horizontal force on the steel strand, kN.
[0027] As mentioned above, after applying a tension force along the length of the steel strand to be constructed, the linear structure of the steel strand between the anchoring base and the tensioning base is as follows: catenaries at both ends and a straight section in the middle, i.e. Figure 2 As shown, the stress-free length of the scale can be calculated using the above formula. S .
[0028] Then, markings can be made based on the stress-free length S of the ruler. The connection point (i.e., the anchor point) between the steel strand to be constructed and the anchoring structure is taken as the starting point of the marking. The calculated stress-free length of the ruler is used to form a stress-free length marking point on the steel strand to be constructed according to the starting point of the marking.
[0029] In some other embodiments of this application, step S5 above has been optimized. Specifically, the method for marking the theoretical stress-free length mark on the steel strand to be constructed based on the theoretical stress-free length and the scale stress-free length mark is as follows: calculate the difference between the theoretical stress-free length and the scale stress-free length, then remove the tension of the steel strand to be constructed, and remove the steel strand to be constructed from the anchoring base and the tensioning base. At this time, there is a marked starting point and a scale stress-free length mark on the steel strand to be constructed. Using the scale stress-free length mark as the reference point, the theoretical stress-free length mark is marked according to the obtained difference.
[0030] Furthermore, in this embodiment, after marking the theoretical stress-free length mark on the steel strand to be constructed, multiple mark points are marked on both sides of the theoretical stress-free length mark at set intervals, centered on the theoretical stress-free length mark. These mark points facilitate subsequent tension control of the steel strand because the mark points are evenly distributed. In this embodiment, the set interval is 0.02m~0.03m (with the stress-free length mark as the center point, a white marker is used to mark the scale within a range of 0.5m before and after, with the marking unit being 2cm, marking one point every 2cm, and drawing a long line every 10cm). For example, when tensioning the steel strand from the fifth mark point to the sixth mark point, since the steel strand material is the same, the corresponding change in cable force is actually determined. In the actual tensioning process, it is only necessary to control all steel strands to be tensioned from the fifth mark point to the sixth mark point to ensure that the change in cable force of all steel strands is the same, achieving the effect of uniform tension control.
[0031] In other embodiments of this application, step S6 described above is optimized. Specifically, the method for tensioning the steel strand to be constructed according to the theoretical stress-free length marker is as follows: the starting point of the steel strand to be constructed is installed at the tower end anchorage point, and the theoretical stress-free length marker on the steel strand to be constructed is installed on the beam segment. At this point, the steel strand between the beam end and the tower end can be considered to be in a stress-free state. Then, the jacks of the beam segment can be used to tension the steel strand to be constructed step by step to the set cable force. The markers mentioned above can also be used for tension control.
[0032] The tension control of the steel strand in this application is specifically carried out according to the following method: Before cutting the steel strand, the steel strand is checked to ensure that the cutting length meets the requirements for anchoring, tensioning, marking, and stress-free cable length. Then, the theoretical stress-free length of the steel strand to be constructed is calculated based on the finite element model. One end of the steel strand to be constructed is fixedly connected to the anchoring base anchored on the horizontal plane, and the end of the steel strand to be constructed passes through the crossbeam on the anchoring base and is fixedly connected to the anchoring base. The other end of the steel strand to be constructed passes through the tensioning base anchored on the horizontal plane, and the other end of the steel strand to be constructed passes through the tensioning jack on the tensioning base and is installed with an anchor gauge. Tension is applied to the steel strand to be constructed so that the difference between the calculated stress-free length on the scale and the theoretical stress-free length after tensioning is within the set range. According to the anchor gauge reading, the steel strand to be constructed is gradually tensioned using the tensioning jack, with the tension increasing from 0.2t to 1t (in actual applications, this value is not limited to, i.e., gradually increasing from a smaller value). (Pull to the set tension); then record various data during the tensioning process, and obtain the theoretical stress-free length based on the above formula; take the connection point between the steel strand to be constructed and the anchorage structure as the starting point, and form a scale stress-free length mark point on the steel strand to be constructed according to the calculated scale stress-free length; remove the tensioning jacks, remove the steel strand to be constructed from the anchorage base and tensioning base, calculate the difference between the theoretical stress-free length and the scale stress-free length, and mark the theoretical stress-free length mark point on the steel strand to be constructed after the tension is removed according to the difference and the stress-free length mark point; mark multiple mark points on both sides of the theoretical stress-free length mark point at a set interval, with the theoretical stress-free length mark point as the center; then install the steel strand to be constructed, install the marked starting point on the steel strand to be constructed to the tower end anchorage point, install the theoretical stress-free length mark point on the steel strand to be constructed to the beam segment, and use the jacks of the beam segment to tension the steel strand to be constructed to the set cable force step by step.
[0033] The foregoing has shown and described the basic principles, main features, and advantages of this application. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this application. Various changes and modifications can be made to this application without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of this application as claimed. The scope of protection of this application is defined by the appended claims and their equivalents.
Claims
1. A method for controlling the tension of steel strand cable, characterized in that: include, The theoretical stress-free length of the steel strand to be constructed was calculated based on the finite element model. Connect one end of the steel strand to be constructed to the anchoring structure and the other end to the tensioning structure. Based on the tensioning structure, a set tension force is applied to the steel strand to be constructed. The stress-free length of the steel strand to be constructed under the current state is calculated according to the shape of the steel strand to be constructed between the tensioning structure and the anchoring structure and the tensioning force. Mark the steel strands to be constructed according to the calculated stress-free length of the ruler to form stress-free length marking points; Based on the theoretical stress-free length and the scale stress-free length marking points, mark the theoretical stress-free length marking points on the steel strand to be constructed; Tensioning is carried out on the steel strands to be constructed according to the theoretical stress-free length marking points.
2. The method for controlling the tension of steel strand cable as described in claim 1, characterized in that: The method for calculating the stress-free length of the scale includes... Calculate the stress-free length of the scale using the following formula. in: S —The stress-free length of the steel strand to be constructed; S 1 —The stress-free length of a single catenary formed when the steel strand to be constructed is tensioned in the tensioning structure; S 2 —The stress-free length of the straight section formed when the steel strand to be constructed is tensioned in the tensioning structure; L 1 —The horizontal length of a single catenary formed when the steel strand to be constructed is tensioned in the tensioning structure; L 2 —The horizontal length of the straight section formed when the steel strand to be constructed is tensioned in the tensioning structure; F —The tensile force applied to the steel strands to be constructed in a tensioned structure; E —The elastic modulus of the steel strand to be constructed; A —The cross-sectional area of the steel strand to be constructed; l —The horizontal distance between a point on the catenary formed when the steel strand to be constructed is tensioned in the tensioning structure and the anchoring point connecting the anchoring structure and the steel strand to be constructed; a、a 1 —Parameters of the catenary equation; q —Intensity of self-weight load of the steel strands to be constructed; x —The horizontal distance between a point on the steel strand to be constructed and the anchorage point connecting the tensioning structure and the steel strand to be constructed; y —The distance from a point on the steel strand to be constructed to the horizontal plane, where the horizontal plane refers to the horizontal plane at the bottom of the anchoring structure and tensioning structure; c — A coefficient related to the horizontal force and self-weight load intensity of the steel strand to be constructed; H — Horizontal force on the steel strand.
3. The method for controlling the tension of steel strand cable as described in claim 1, characterized in that: The method of connecting one end of the steel strand to be constructed to the anchoring structure and the other end to the tensioning structure includes: fixing one end of the steel strand to be constructed to the anchoring base anchored on the horizontal plane, and the end of the steel strand to be constructed passing through the crossbeam on the anchoring base and fixing it to the anchoring base; passing the other end of the steel strand to be constructed through the tensioning base anchored on the horizontal plane, and the other end of the steel strand to be constructed passing through the tensioning jack on the tensioning base and installing the anchor cable gauge.
4. The method for controlling the tension of steel strand cable as described in claim 1, characterized in that: The method for applying a set tension force to the steel strand to be constructed based on a tension structure includes: applying a tension force to the steel strand to be constructed so that the difference between the calculated stress-free length on the scale and the theoretical stress-free length after the steel strand to be constructed is within a set range.
5. The method for controlling the tension of steel strand cable as described in claim 4, characterized in that: The set range is ±0.5m.
6. The method for controlling the tension of steel strand cable as described in claim 1, characterized in that: The method for marking the steel strand to be constructed according to the calculated stress-free length of the ruler to form a ruler stress-free length mark point includes: after calculating the stress-free length of the ruler, taking the connection point between the steel strand to be constructed and the anchoring structure as the marking starting point, and forming a ruler stress-free length mark point on the steel strand to be constructed according to the calculated stress-free length of the ruler and the marking starting point.
7. The method for controlling the tension of steel strand cable as described in claim 1, characterized in that: The method for marking theoretical stress-free length markers on the steel strand to be constructed based on theoretical stress-free length and scale stress-free length markers includes: calculating the difference between theoretical stress-free length and scale stress-free length, and marking the steel strand to be constructed after the tension is removed according to the difference and the stress-free length markers to form theoretical stress-free length markers.
8. The method for controlling the tension of steel strand cable as described in claim 7, characterized in that: After marking the theoretical stress-free length mark on the steel strand to be constructed, mark multiple marks on both sides of the theoretical stress-free length mark at set intervals, with the theoretical stress-free length mark as the center.
9. The method for controlling the tension of steel strand cable as described in claim 8, characterized in that: The set interval is 0.02m to 0.03m.
10. The method for controlling the tension of a steel strand cable as described in claim 6, characterized in that: The method for tensioning the steel strand to be constructed according to the theoretical stress-free length marker points includes: installing the marked starting point on the steel strand to be constructed to the tower end anchor point, installing the theoretical stress-free length marker points on the steel strand to be constructed to the beam segment, and using the jacks of the beam segment to tension the steel strand to be constructed step by step to the set cable force.