A method for supplementary tensioning of bolts of a cable clip of a suspension bridge

Abstract

The present application relates to a method for supplementary tensioning of cable clamp bolts of a suspension bridge, including: tensioning the nth group of cable clamp bolts with a first tightening force and measuring the first echo time of ultrasonic waves in its screw rod; continuously loading to the design tightening force, tensioning the nth group of cable clamp bolts and measuring the second echo time of ultrasonic waves in its screw rod; tightening the nut and unloading the design tightening force to complete the tensioning of the nth group of cable clamp bolts and measuring the third echo time of ultrasonic waves in its screw rod; repeating the above steps until the tensioning of N groups of cable clamp bolts is completed; calculating the tightening force loss of each group of cable clamp bolts; tensioning each group of cable clamp bolts with the tensioning control force of each group of cable clamp bolts respectively, tightening the nut and unloading the tensioning control force to complete the tensioning. The present invention provides a method for supplementary tensioning of cable clamp bolts of a suspension bridge, which is particularly applicable to suspension bridges during the operation period, precisely considers the tightening force loss of cable clamp bolts after tensioning, and the supplementary tensioning is more accurate.

Description

Technical Field

[0001] The present application relates to the technical field of bridge maintenance, and particularly relates to a method for supplementary tensioning of the clamp bolts of a suspension bridge during the operation period. Background Art

[0002] The clamp of a suspension bridge is one of the main components of the upper structure of the suspension bridge. After the suspension bridge is opened to traffic, due to various reasons such as vehicle load, vibration of the suspension cables, creep of the galvanized steel wires in the main cable, shrinkage of the main cable diameter, and bolt relaxation, the tightening force of the clamp bolts generally gradually decreases. If the tightening force of the clamp bolts is too small, it will cause the clamp to slip, which will in turn affect the force change of the entire structural system. The result is irreversible and difficult to recover. At the same time, it will also cause the main cable steel wires to be exposed, seriously affecting the structural durability.

[0003] At present, preventing the slip of the clamp has become the focus of the maintenance of suspension bridges. In Article 3.5.9 of the Highway Bridge and Culvert Maintenance Specification (2021), the requirements for regular inspection of the main components of the suspension bridge stipulate that "check whether the clamp bolts are missing, damaged, or loose; whether the clamp is misaligned or slipped; test the tightening force of the clamp bolts".

[0004] In the related art, the methods for supplementary tensioning of the tightening force of the clamp bolts of the suspension bridge mainly include:

[0005] 1. Tension the clamp bolts in batches by a jack according to the design tightening force until the tightening force of all bolts meets the requirements. Since there will be a certain amount of retraction after the nut is tightened and unloaded, it is impossible to determine the true tightening force actually existing in the bolts. At the same time, batch tensioning results in poor tensioning uniformity.

[0006] 2. Measure the linear correlation coefficient between the ultrasonic propagation time and the axial force of the screw to be installed in the laboratory, then measure the ultrasonic propagation time in the screw to be installed under the stress-free state, then carry out tensioning, and calculate the loss of axial force of the screw to correct the tensioning control force. For a suspension bridge during the operation period, the stress-free state cannot be obtained, and the clamp bolts of the suspension bridge during the operation period may already be in a rusted state, which is different from the state to be installed in the laboratory, and the linear correlation coefficient is difficult to reflect the actual situation during the operation period.

[0007] 3. Calculate the average axial force of the grouped bolts based on the tightening force of each bolt before tensioning, measure the change in the main cable diameter before and after tensioning, and inversely calculate the additional pre-tightening force required for the first group of tensioning to reach the design value after grouped tensioning. However, in a suspension bridge during the operation period, the main cable has been wrapped, and there is a large error in measuring the main cable diameter. Moreover, for large-sized clamps, the main cable diameter is not completely consistent along the length direction of the clamp. Summary of the Invention

[0008] An embodiment of the present application provides a method for supplementary tensioning of the cable clamp bolts of a suspension bridge to solve the technical problems in the related art that the existing method for supplementary tensioning of cable clamp bolts is not applicable to suspension bridges during the operation period and the tensioning uniformity is poor.

[0009] An embodiment of the present application provides a method for supplementary tensioning of the cable clamp bolts of a suspension bridge. The method for supplementary tensioning of the cable clamp bolts of the suspension bridge includes the following steps:

[0010] Tension the nth group of cable clamp bolts with a first tightening force F1, and measure the first echo time t of ultrasonic waves in its screw rod n,1 ; where n is a positive integer less than or equal to N, and N is the total number of groups of cable clamp bolts;

[0011] Continue to load to the design tightening force F2, tension the nth group of cable clamp bolts, and measure the second echo time t of ultrasonic waves in its screw rod n,2 ;

[0012] Tighten the nut, unload the design tightening force F2, complete the tensioning of the nth group of cable clamp bolts, and measure the third echo time t of ultrasonic waves in its screw rod n,3 ;

[0013] Repeat the above steps until the tensioning of N groups of cable clamp bolts is completed;

[0014] According to the first tightening force F1, the design tightening force F2, the first echo time t n,1 , the second echo time t n,2 , the third echo time t n,3 Calculate the tightening force loss ΔF of each group of cable clamp bolts n , to determine the tensioning control force F required for the actual tightening force of each group of cable clamp bolts to reach the design tightening force n,4 ;

[0015] Tension each group of cable clamp bolts with the tensioning control force F of each group of cable clamp bolts n,4 respectively, tighten the nut, unload the tensioning control force F n,4 , and complete the tensioning.

[0016] In some embodiments, the first tightening force F1 is 60%-80% of the design tightening force F2.

[0017] In some embodiments, among the N groups of cable clamp bolts, each group of cable clamp bolts is symmetric up and down.

[0018] In some embodiments, the calculation formula for the tightening force loss ΔF of each group of cable clamp bolts n is:

[0019] ΔF n = K n × (tn,2 -t n,3 )

[0020] where K n is the proportionality coefficient between the ultrasonic echo time and the fastening force.

[0021] In some embodiments, the calculation formula of the proportionality coefficient K n is

[0022] In some embodiments, the tension control force F n,4 of each group of cable clamp bolts n，4 is calculated as: F n = F2 + ΔF

[0023] In some embodiments, each group of cable clamp bolts is tensioned with the tension control force F n,4 of each group of cable clamp bolts respectively. After the tensioning is completed, the following steps are further included:

[0024] Measure the fourth echo time t of the ultrasonic wave in its screw rod n,4 , and calculate the deviation σ between the actual fastening force and the designed fastening force;

[0025] If the deviation meets the requirements, end; if the deviation does not meet the requirements, re-tension each group of cable clamp bolts with the tension control force F n,4 of each group of cable clamp bolts.

[0026] In some embodiments, the calculation formula of the deviation σ is:

[0027]

[0028] In some embodiments, a jack is used to tension the N groups of cable clamp bolts.

[0029] In some embodiments, when tensioning the nth group of cable clamp bolts, the cable clamp bolts in the same group are tensioned synchronously.

[0030] The beneficial effects brought by the technical solution provided by this application include:

[0031] This application provides a method for supplementary tensioning of cable clamp bolts of a suspension bridge, which is particularly applicable to suspension bridges during the operation period. By using the echo times of three ultrasonic waves and the loading of two fastening forces, the actual fastening force loss can be calculated, and based on this, the tension control force required for the actual fastening force of the cable clamp bolts to reach the designed fastening force can be determined. The fastening force loss after tensioning is accurately considered, such as the shrinkage loss of the bolts themselves and the influence of the previously tensioned bolts on the subsequently tensioned bolts, and the supplementary tensioning is more accurate.

[0032] Moreover, the supplementary tensioning method provided in this application is applied to a suspension bridge during the operation period. Even if the clamp bolts are in a rusted state, the detection can be carried out normally, avoiding the problem that the difference between the actual situation and the initial stress-free state is relatively large, resulting in inaccurate and untrue results, ensuring the uniformity of the tightening force of each group of clamp bolts, and at the same time ensuring that the true value meets the design requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0034] Figure 1 It is a schematic diagram before and after tensioning of the clamp bolts in an embodiment of the present invention.

[0035] Figure 2 It is a schematic structural diagram of three groups of clamp bolts in an embodiment of the present invention.

[0036] Reference numerals:

[0037] 1. Clamp bolt; 11. Screw rod; 12. Nut; 2. Ultrasonic probe. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] In order to make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts fall within the scope of protection of the present application.

[0039] The embodiments of the present application provide a supplementary tensioning method for the clamp bolts of a suspension bridge, including the following steps:

[0040] Step S1: Tension the nth group of clamp bolts with a first tightening force F1, and measure the first echo time t of the ultrasonic wave in its screw rod n,1 ; where n is a positive integer less than or equal to N, representing the grouping number, and N is the total number of groups of clamp bolts;

[0041] Step S2: Continue to load to the design tightening force F2, tension the nth group of clamp bolts, and measure the second echo time t of the ultrasonic wave in its screw rod n,2 ;

[0042] Step S3, tighten the nut, unload the designed tightening force F2, complete the tensioning of the nth group of cable clamp bolts, and measure the third echo time t of the ultrasonic wave in its screw. n,3 ;

[0043] Repeat the above steps S1-S3 until the N groups of cable clamp bolts are tensioned;

[0044] Step S4: according to the first tightening force F1, the designed tightening force F2, and the first echo time t n,1 , second echo time t n,2 , the third echo time t n,3 Calculate the tightening force loss ΔF of each set of cable clamp bolts n To determine the tension control force F required when the actual tightening force of each group of cable clamp bolts reaches the designed tightening force n,4 ;

[0045] Step S5: Using the tension control force F of each set of cable clamp bolts n,4 Tension each set of cable clamp bolts respectively, tighten the nuts, and unload the tension control force F n,4 , complete the tensioning.

[0046] An embodiment of the present application provides a method for re-tensioning cable clamp bolts of a suspension bridge, which is particularly suitable for suspension bridges in operation. The actual tightening force loss can be calculated through three ultrasonic echo times and two tightening force loadings, and the tensioning control force required when the actual tightening force of the cable clamp bolt reaches the designed tightening force is determined accordingly. The tightening force loss of the cable clamp bolt after the tensioning is completed is accurately considered, such as the loss of its own retraction and the influence of the first tensioning bolt on the later tensioning bolt, so that the re-tensioning is more accurate.

[0047] Moreover, the tensioning method provided in the embodiment of the present application is applied to suspension bridges in operation. Even if the cable clamp bolts are in a rusted state, normal inspection can be carried out, thereby avoiding the problem of inaccurate and untrue results caused by a large difference between the actual situation and the initial stress-free state, ensuring the uniformity of the tightening force of each group of cable clamp bolts, and ensuring that the actual value meets the design requirements.

[0048] In some embodiments, if there are a large number of cable clamp bolts and they cannot be tensioned synchronously as a whole according to the existing method, all the cable clamp bolts are grouped and processed in batches according to the method provided in the embodiments of the present application, and are divided into N groups of cable clamp bolts. The specific grouping is reasonably arranged according to the number of cable clamp bolts and the number of tensioning equipment. For example, each group of cable clamp bolts can be symmetrical up and down, or symmetrical left and right.

[0049] In some embodiments, through-hole jacks are used to tension the N groups of cable clamp bolts.

[0050] In some embodiments, in step S1, the first tightening force F1 is 60%-80% of the designed tightening force F2. This force value is converted into the oil pressure of the oil pump through a calibration formula, and the tension value is controlled by the oil pressure. The calibration formulas of the jacks in the same group are as consistent as possible to ensure that under the control of the same oil pressure, the actual tensions of each jack are the same.

[0051] In some embodiments, when tensioning the bolt of the nth group of cable clamps, the bolts of the same group are tensioned synchronously. Since the bolts of the same group are tensioned synchronously, the echo durations are not very different, and the average value can be taken as the echo duration of this group.

[0052] Taking N = 3, that is, 3 groups of cable clamp bolts as an example, the specific tensioning process is as follows:

[0053] First, tension the bolts of the first group of cable clamps:

[0054] Tension the bolts of the first group of cable clamps with the first tightening force F1 (such as 80% of the designed tightening force F2), hold the load, send an ultrasonic signal, and measure the first echo time t of the ultrasonic wave in its screw rod 1,1 ;

[0055] Continue to load to the designed tightening force F2, tension the bolts of the first group of cable clamps, hold the load, send an ultrasonic signal, and measure the second echo time t of the ultrasonic wave in its screw rod 1,2 ;

[0056] Tighten the nut, unload the designed tightening force F2, complete the tensioning of the bolts of the first group of cable clamps, and measure the third echo time t of the ultrasonic wave in its screw rod 1,3 .

[0057] Then, tension the bolts of the second group of cable clamps:

[0058] Tension the bolts of the second group of cable clamps with the first tightening force F1 (80% of the designed tightening force F2), hold the load, send an ultrasonic signal, and measure the first echo time t of the ultrasonic wave in its screw rod 2,1 ;

[0059] Continue to load to the designed tightening force F2, tension the bolts of the second group of cable clamps, hold the load, send an ultrasonic signal, and measure the second echo time t of the ultrasonic wave in its screw rod 2,2 ;

[0060] Tighten the nut, unload the designed tightening force F2, complete the tensioning of the bolts of the second group of cable clamps, and measure the third echo time t of the ultrasonic wave in its screw rod 2,3 .

[0061] Then, tension the bolts of the third group of cable clamps:

[0062] Tension the third group of clamp bolts with the first tightening force F1 (80% of the designed tightening force F2), hold the load, send ultrasonic signals, and measure the first echo time t of the ultrasonic wave in its screw rod 3,1 ;

[0063] Continue to load up to the designed tightening force F2, tension the third group of clamp bolts, hold the load, send ultrasonic signals, and measure the second echo time t of the ultrasonic wave in its screw rod 3,2 ;

[0064] Tighten the nut and unload the designed tightening force F2 to complete the tensioning of the third group of clamp bolts, and measure the third echo time t of the ultrasonic wave in its screw rod 3,3 Thus, the tensioning of the three groups of clamp bolts is completed, and the next step is entered.

[0065] In step S4, according to the first tightening force F1, the designed tightening force F2, the first echo time t n,1 , the second echo time t n,2 , and the third echo time t n,3 Calculate the tightening force loss ΔF of each group of clamp bolts n , the tightening force loss ΔF of each group of clamp bolts n The calculation formula is:

[0066] ΔF n = K n × (t n,2 - t n,3 );

[0067] Among them, K n is the proportionality coefficient between the ultrasonic echo time and the tightening force.

[0068] In some embodiments, the calculation formula of the proportionality coefficient K n is

[0069] As Figure 1 shown Figure 1 This is a schematic diagram of the clamp bolts before and after tensioning in an embodiment of the present invention.

[0070] The clamp bolt 1 includes a screw rod 11 and a nut 12 that mates with the screw rod 11, and the ultrasonic probe 2 is placed at the top of the screw rod 11.

[0071] Since the ultrasonic echo duration is related to the path traveled, i.e., the length of the cable clamp bolt. The length of the bolt is L under the stress-free state (before tensioning). After tensioning and being subjected to force, the bolt length is L′, and the elongation is Δl. The difference in echo duration between the stress-free state and the stressed state is Δt. According to the ultrasonic measurement principle, the elongation Δl is proportional to the difference in echo duration Δt, and the elongation Δl is also proportional to the tightening force F. Therefore, the difference in echo duration Δt is proportional to the tightening force F, and the proportionality coefficient is defined as K n , the derivation process is as follows:

[0072] F1 = K n ×(t n,1 - t n,0 ); F2 = K n ×(t n,2 - t n,0 ); F n,3 = K n ×(t n,3 - t n,0 );

[0073] F2 - F1 = K n ×(t n,2 - t n,1 );

[0074] The calculation formula for the proportionality coefficient K n is:

[0075] Then the tightening force loss ΔF n of each group of cable clamp bolts is calculated as:

[0076]

[0077] According to the above calculation formula, it can be seen that for each group of cable clamp bolts, considering the retraction loss and the influence of the pre-tensioned bolts on the post-tensioned bolts, the actual remaining bolt tightening force F n,3 , compared with the design value, the tightening force loss ΔF n of each group of cable clamp bolts can be obtained. Thus, the tension control force F n,4 required for the actual tightening force of each group of cable clamp bolts to reach the design tightening force can be determined.

[0078] In some embodiments, the calculation formula for the tension control force F n,4 of each group of cable clamp bolts is: F n，4 = F2 + ΔF n .

[0079] In some embodiments, using the tension control force F n,4 of each group of cable clamp bolts to tension each group of cable clamp bolts respectively. After the tensioning is completed, the following steps are further included:

[0080] Measure the fourth echo time t of the ultrasonic wave in the screw n,4 , calculate the deviation σ between the actual tightening force and the designed tightening force;

[0081] If the deviation meets the requirements, the process ends; if the deviation does not meet the requirements, the tension control force F is used again. n,4 Tension each set of cable clamp bolts.

[0082] In some embodiments, the deviation σ is calculated as:

[0083]

[0084] The present invention is described in detail below through a specific embodiment.

[0085] Preparation: Install a mobile hanging basket on the main cable handrail as a construction platform, remove the bolt waterproof nut, spray rust remover and use a steel brush to remove rust. Group the cable clamp bolts according to their arrangement, quantity and the number of tensioning equipment. The grouping principle is symmetry up and down to facilitate personnel operation and oil pipe connection. If the jack legs cannot be placed, they can be arranged crosswise. n is the group number. Taking three groups as an example, n is 1, 2, 3. The specific grouping is reasonably arranged according to the number of bolts and tensioning equipment.

[0086] like Figure 2 As shown, Figure 2 Schematic diagram of the structure of three groups of cable clamp bolts in one embodiment of the present invention.

[0087] In this embodiment, the cable clamp has a total of 12 bolts, with a bolt specification of 36mm in diameter and a designed axial force F2 of 490KN. It is divided into 3 groups from left to right, with 4 bolts in each group. Synchronous tensioning is adopted, and a high-pressure oil pump controls 4 through-hole jacks. The calibration formulas of the 4 jacks are basically the same. The tensioning tooling is installed, and the cable clamp bolts are tensioned by the through-hole jacks. After the tensioning construction of one group of cable clamp bolts is completed, the tensioning tooling is moved to carry out the tensioning construction of the next group of cable clamp bolts.

[0088] First, tension the first set of cable clamp bolts:

[0089] The first set of cable clamp bolts are tensioned with the first tightening force F1 (80% of the designed tightening force F2, 392KN), the load is maintained, ultrasonic signals are sent, and the first echo time t of the ultrasonic wave in the screw is measured. 1,1 ;

[0090] Continue to load to the designed tightening force F2 (490KN), tension the first set of cable clamp bolts, hold the load, send ultrasonic signals, and measure the second echo time t of the ultrasonic wave in its screw. 1,2 ;

[0091] Tighten the nut, unload the designed fastening force F2, complete the tensioning of the first group of clamp bolts, and measure the third echo time t of the ultrasonic wave in its screw rod 1,3 。

[0092] Then move the tensioning tooling and testing equipment to the next group and perform the tensioning of the second group of clamp bolts:

[0093] Tension the second group of clamp bolts with the first fastening force F1 (80% of the designed fastening force F2), hold the load, send an ultrasonic signal, and measure the first echo time t of the ultrasonic wave in its screw rod 2,1 ;

[0094] Continue to load up to the designed fastening force F2, tension the second group of clamp bolts, hold the load, send an ultrasonic signal, and measure the second echo time t of the ultrasonic wave in its screw rod 2,2 ;

[0095] Tighten the nut, unload the designed fastening force F2, complete the tensioning of the second group of clamp bolts, and measure the third echo time t of the ultrasonic wave in its screw rod 2,3 。

[0096] Then move the tensioning tooling and testing equipment to the next group and perform the tensioning of the third group of clamp bolts:

[0097] Tension the third group of clamp bolts with the first fastening force F1 (80% of the designed fastening force F2), hold the load, send an ultrasonic signal, and measure the first echo time t of the ultrasonic wave in its screw rod 3,1 ;

[0098] Continue to load up to the designed fastening force F2, tension the third group of clamp bolts, hold the load, send an ultrasonic signal, and measure the second echo time t of the ultrasonic wave in its screw rod 3,2 ;

[0099] Tighten the nut, unload the designed fastening force F2, complete the tensioning of the third group of clamp bolts, and measure the third echo time t of the ultrasonic wave in its screw rod 3,3 。Thus, the tensioning of the 3 groups of clamp bolts is completed, and the results of the echo time are shown in Table 1.

[0100] It should be noted that during the measurement of the third echo time in the above process, 1 clamp bolt is selected from each group of clamp bolts for measurement.

[0101] According to the first fastening force F1, the designed fastening force F2, the first echo time t n,1 、the second echo time t n,2 、the third echo time t n,3 Calculate the fastening force loss ΔF of each group of clamp bolts n to determine the tensioning control force F required for the actual fastening force of each group of clamp bolts to reach the designed fastening forcen,4 ; The results are shown in Table 1.

[0102] With the tension control force F of each group of clamp bolts n,4 Tension each group of clamp bolts respectively, tighten the nuts, and unload the tension control force F n,4 , and complete the tensioning.

[0103] After completing the tensioning, select 1 clamp bolt from each group of clamp bolts, and measure the fourth echo time t of the ultrasonic wave in its screw n,4 , and calculate the deviation σ between the actual fastening force and the designed fastening force; the results are shown in Table 1.

[0104] Table 1 Results

[0105] Number of cable clip bolts 1 2 3 <![CDATA[First echo time t n,1 (μs)]]> 319.7518 319.9165 319.8612 <![CDATA[Second echo time t n,2 (μs)]]> 320.2365 320.3990 320.3468 <![CDATA[Third echo time t n,3 (μs)]]> 319.5518 319.9856 319.9777 <![CDATA[Proportionality coefficient K n > 202.2 203.1 201.8 <![CDATA[Tightening force loss ΔF n (KN)]]> 138.4 84.0 74.5 <![CDATA[Tensile control force F n,4 (KN)]]> 628.4 574 564.5 <![CDATA[Fourth echo time t n,4 (μs)]]> 320.1879 320.3669 320.3621 Deviation σ -2.005％ -1.331％ 0.6301％

[0106] Taking the first group of clamp bolts as an example, the calculation process is as follows:

[0107] The first fastening force F1 = 392 KN, the designed fastening force F2 = 490 KN, the first echo time t n,1 = 319.7518 μs, the second echo time t n,2 = 320.2365 μs, then

[0108] Proportionality coefficient

[0109] Fastening force loss

[0110] ΔF1 = K1×(t 1,2 -t 1,3 ) = 202.2×(320.2365 - 319.5518) = 138.4 KN;

[0111] Tension control force F 1，4 = F2 + ΔF1 = 490 + 138.4 = 628.4 KN.

[0112] Deviation σ = K1×(t 1,4 -t 1,2 ) / F2 = 202.2×(320.1879 - 320.2365) / 490 = -2.005%.

[0113] It can be seen from Table 1 that compared with the designed fastening force, the supplementary tensioning method provided by the embodiment of the present application is applied to the suspension bridge during the operation period, and the errors are all within 5%, and the deviations between each other are also within 5%, and the tensioning uniformity is well guaranteed.

[0114] The anti-slip resistance of the cable clamp is directly proportional to the uneven distribution coefficient of the fastening pressure and the fastening force of the cable clamp bolts. The greater the anti-slip resistance of the cable clamp and the greater the anti-slip coefficient, the lower the risk of cable clamp slip. The supplementary tensioning method provided by the embodiments of the present application can ensure that the two key factors affecting the anti-slip coefficient of the cable clamp, namely, the uneven distribution coefficient of the fastening pressure and the fastening force of the cable clamp bolts, meet the requirements and prevent the cable clamp from slipping.

[0115] In the description of the present application, it should be noted that the orientation or positional relationship indicated by terms such as "upper" and "lower" is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the method or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present application. Unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, "connection" 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 directly connected or indirectly connected through an intermediate medium, and it can be the communication inside 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 specific circumstances.

[0116] It should be noted that in the present 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 actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the element.

[0117] The above are only specific embodiments of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious 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 these embodiments shown herein, but rather will be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for supplementary tensioning of bolts of a cable clamp of a suspension bridge, characterized in that, The method for supplementary tensioning of the cable clamp bolts of the suspension bridge comprises the following steps: Tension the nth group of stay cable clamp bolts with the first tightening force F1, and measure the first echo time t of ultrasonic waves in its screw rod n,1 ; where n is a positive integer less than or equal to N, and N is the total number of groups of stay cable clamp bolts; Continue to load until the design fastening force F2 is reached, tension the nth group of staybolt clamps, and measure the second echo time t of ultrasonic waves in its screw rod n,2 ; Tighten the nut, unload the designed fastening force F2, complete the tensioning of the nth group of stay cable clamp bolts, and measure the third echo time t of ultrasonic waves in its screw rod n,3 ; Repeat the above steps until the tensioning of N groups of cable clamp bolts is completed; According to the first fastening force F1, the designed fastening force F2, the first echo time t n,1 , the second echo time t n,2 , the third echo time t n,3 Calculate the fastening force loss ΔF of each group of clamp bolts n to determine the tension control force F required when the actual fastening force of each group of clamp bolts reaches the designed fastening force n,4 ; With the tensile control force F of each group of clamp bolts n,4 Tension each group of clamp bolts respectively, tighten the nuts and unload the tensile control force F n,4 , and complete the tensioning.

2. The supplementary tensioning method of the cable clip bolt of a suspension bridge according to claim 1, characterized in that, The first fastening force F1 is 60%-80% of the designed fastening force F2.

3. A method for supplementary tensioning of the cable clamp bolts of a suspension bridge according to claim 1, characterized in that, Among the N groups of cable clamp bolts, each group of cable clamp bolts is symmetrically arranged up and down.

4. A method for supplementary tensioning of the bolts of a suspension bridge cable clamp according to claim 1, characterized in that, The tightening force loss ΔF of each group of cable clamps n The calculation formula is as follows: ΔF n = K n × (t n,2 - t n,3 ); Among them, K n is the proportionality coefficient between the ultrasonic echo time and the tightening force.

5. The supplementary tensioning method for the cable clamp bolts of a suspension bridge according to claim 4, characterized in that, The proportionality coefficient K n has the following calculation formula:

6. A method for supplementary tensioning of the cable clamp bolts of a suspension bridge according to claim 1, characterized in that, The tensile control force F of each group of stay cable clamps n,4 is calculated by the following formula: F n，4 = F2 + ΔF n .

7. A method for supplementary tensioning of the cable clamp bolts of a suspension bridge as described in claim 1, characterized in that The tensile control force F of each group of clamp bolts n,4 Tension each group of clamp bolts respectively. After the tensioning is completed, the following steps are further included: Measure the fourth echo time t of the ultrasonic wave in its screw n,4 , and calculate the deviation σ between the actual tightening force and the designed tightening force; If the deviation meets the requirements, it ends; if the deviation does not meet the requirements, the tension control force F is reapplied. n,4 Tension the bolts of each group of cable clamps.

8. A method for supplementary tensioning of the cable clamp bolts of a suspension bridge according to claim 7, characterized in that, The calculation formula for the deviation σ is as follows:

9. The supplementary tensioning method for the cable clamp bolts of a suspension bridge according to claim 1, characterized in that, Use a jack to tension the N groups of cable clamp bolts.

10. A method for supplementary tensioning of the cable clamp bolts of a suspension bridge according to claim 1, characterized in that, When tensioning the nth group of cable clamp bolts, the cable clamp bolts in the same group are tensioned synchronously.

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