CN111535195A - Suspension bridge cable clamp screw tensioning device and method - Google Patents
Suspension bridge cable clamp screw tensioning device and method Download PDFInfo
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- CN111535195A CN111535195A CN202010419701.4A CN202010419701A CN111535195A CN 111535195 A CN111535195 A CN 111535195A CN 202010419701 A CN202010419701 A CN 202010419701A CN 111535195 A CN111535195 A CN 111535195A
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- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
- E01D21/00—Methods or apparatus specially adapted for erecting or assembling bridges
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- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
- E01D11/00—Suspension or cable-stayed bridges
- E01D11/02—Suspension bridges
Abstract
The invention relates to the technical field of bridge construction, and provides a device and a method for tensioning a cable clamp screw of a suspension bridge, wherein the device comprises: the penetrating type tensioning device is sleeved on the screw rod, and one end of the penetrating type tensioning device is propped against the surface of the tensioning end of the cable clamp; the fixed anchorage is sleeved on the screw and abuts against the other end of the feed-through type tensioning device; the device also comprises an ultrasonic excitation and acquisition device which is used for exciting the screw rod and acquiring ultrasonic signals; the device further comprises an analysis and control device which is in signal connection with the ultrasonic excitation and acquisition device and used for sending out an ultrasonic excitation instruction, a tensioning instruction and an unloading instruction, and also used for analyzing the ultrasonic signals to calculate the actual tensioning efficiency and judge whether the actual axial force of the screw is greater than the designed axial force after tensioning is finished. The safety risk problem that the real axial force of the screw is lower after the screw is stretched due to retraction of the screw in the prior art can be solved.
Description
Technical Field
The invention relates to the technical field of bridge construction, in particular to a device and a method for tensioning a cable clamp screw of a suspension bridge.
Background
The axial force of a screw rod of a cable clamp of a suspension bridge is a main factor for ensuring the anti-sliding performance of the cable clamp. The insufficient axial force of the cable clamp screw can lead the cable clamp to slide on the cable body, so that the deviation of a connecting node of the sling is caused, the stress state of the stiffening beam and the sling is changed, and the structural performance such as the integral stability and the bearing capacity of the structure is adversely affected. Meanwhile, the slippage of the cable clamp on the main cable can damage the winding and the rust-proof layer of the main cable, so that the main cable is damaged, and the durability of the main cable is influenced.
At present, a jack is driven by a suspension bridge cable clamp screw rod through a manually operated oil pump, tension force is controlled by observing reading of a mechanical pressure gauge, a screw nut is screwed when the tension reaches a designed tonnage, the oil pump is unloaded, and the screw rod tension is completed. Because the screwing degree of the nut is difficult to control, the screw rod can retract inevitably after the oil pump is unloaded, so that the axial force loss of the screw rod is caused, and the design axial force of the screw rod multiplied by the safety factor is often used as the design tension force in the tensioning construction of the cable clamp screw rod of the suspension bridge at present to perform tensioning so as to offset the axial force loss caused by the retraction of the screw rod.
However, the safety factor is an empirical value set according to past experience, and often cannot completely offset the axial force loss caused by the retraction of the screw, so that the actual construction quality of the screw is difficult to guarantee. The prior art CN110158476A considers the axial force redistribution in the cable clamp screw group tension process, but does not consider the axial force loss caused by screw retraction. In the prior art, the CN110761186A reduces the retraction of the screw by setting the rotation angle range of the screw nut, but the real axial force in the screw after tensioning is finished cannot be accurately estimated, and the precision of the real axial force needs to be improved. In the prior art, CN107165050A, CN110374003A and CN110359372A improve the screw tensioning precision to a certain extent, but all the screw tensioning precision needs to be tested by ultrasonic calibration in a laboratory, the process is complex, and the efficiency needs to be improved. According to the measured data of a certain bridge, the axial force loss rate of the screw caused by the retraction of the screw is up to 60%, and the axial force loss amount of the screw far exceeds the margin considered by the safety factor.
The loss of the axial force of the screw rod caused by the construction process can cause the inherent defect of the anti-slip performance of the cable clamp, and brings great risk to the bridge construction and the bridge forming operation.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a device and a method for tensioning a suspension bridge cable clamp screw, which can solve the problems that the screw after tensioning is finished in the prior art has inevitable retraction, so that the axial force of the screw is lost, and the safety risk exists.
In order to achieve the above purposes, the technical scheme adopted by the invention is as follows:
the invention provides a suspension bridge cable clamp screw tensioning device, which comprises:
the penetrating type tensioning device is sleeved on the screw rod, and one end of the penetrating type tensioning device is abutted against the surface of the cable clamp;
the fixed anchorage device is sleeved on the screw rod and abuts against the other end of the feed-through type tensioning device;
the ultrasonic excitation and acquisition device is used for being connected with the screw rod and exciting the screw rod and acquiring ultrasonic signals;
the analysis and control device is connected with the ultrasonic excitation and acquisition device, and is used for sending an ultrasonic excitation and acquisition instruction, analyzing the ultrasonic sound of the screw rod before tensioning, when the screw rod is tensioned to a designed tension force and after unloading according to the acquired ultrasonic signals to calculate the tensioning efficiency, determining whether the actual axial force of the screw rod after tensioning is greater than the designed axial force or not, and sending a tensioning instruction and an unloading instruction to adjust the tensioning degree of the through type tensioning device.
On the basis of the scheme, the ultrasonic excitation and acquisition device comprises:
ultrasonic excitation means for emitting an electrical signal that excites an ultrasonic signal;
the ultrasonic acquisition device is used for acquiring an electric signal converted from an ultrasonic signal;
the ultrasonic transducer is used for being arranged at the end part of the screw rod and positioned outside the fixed anchorage device, is connected with the ultrasonic excitation device and the ultrasonic acquisition device, and is used for converting an electric signal sent by the ultrasonic excitation device into an ultrasonic signal and converting an ultrasonic signal transmitted in the screw rod into an electric signal;
and the signal amplifier is arranged between the ultrasonic transducer and the ultrasonic acquisition device and is used for amplifying the electric signal sent by the ultrasonic transducer.
On the basis of the scheme, the ultrasonic transducer is a receiving and transmitting integrated piezoelectric ultrasonic transducer, the outer side of the ultrasonic transducer is provided with an annular magnet, and the annular magnet is used for being adsorbed on the end face of the screw rod.
On the basis of the scheme, the tensioning device further comprises a nut fastening sleeve which is sleeved on the fastening nut at the tensioning end of the screw rod, and the feed-through tensioning device is abutted to the surface of the cable clamp through the nut fastening sleeve.
On the basis of the scheme, the nut fastening external member comprises a pressure-bearing external member and a rotation external member capable of rotating relatively, the pressure-bearing external member is sleeved on the rotation external member, the rotation external member is sleeved on the screw fastening nut, long round holes are formed in the circumferential direction of the pressure-bearing external member at intervals, circular rotation holes are formed in the circumferential direction of the rotation external member at intervals, a steel bar is inserted into the circular rotation holes, and the steel bar can rotate to rotate the external member so as to tighten the fastening nut on the screw.
On the basis of the scheme, the hydraulic device is further included and is connected with the through-type tensioning device and used for providing hydraulic pressure for the through-type tensioning device so as to adjust the tensioning degree of the through-type tensioning device.
On the basis of the scheme, the analysis and control device and the hydraulic device both comprise wireless transmission devices which are used for connecting the analysis and control device and the hydraulic device so as to transmit the tension command and the unloading command sent by the analysis and control device to the hydraulic device for execution.
On the basis of the scheme, the analysis and control device and the hydraulic device can be matched with a plurality of sets of the penetrating type tensioning devices, the fixed anchorage devices and the ultrasonic excitation and acquisition devices for use, so that synchronous tensioning of a plurality of screw rods is realized.
The invention also provides a tensioning method of the suspension bridge cable clamp screw, which comprises the following steps:
s1: calculating a tensioning efficiency threshold according to the design tensioning force and the design axial force of the screw to be tensioned;
s2: before tensioning, carrying out ultrasonic excitation and collection on the screw to obtain ultrasonic sound before tensioning the screw;
s3: tensioning the screw rod to a designed tension force by using a feed-through tensioning device, tightening a fastening nut at the tensioning end of the screw rod, and performing ultrasonic excitation and collection on the screw rod tensioned to the designed tension force to obtain ultrasonic sound of the screw rod tensioned to the designed tension force;
s4: unloading the feed-through tensioning device, and carrying out ultrasonic excitation and acquisition on the unloaded screw to obtain the ultrasonic sound of the unloaded screw;
s5: calculating the actual stretching efficiency of the screw according to the ultrasonic sound before stretching the screw, the ultrasonic sound when stretching to the designed stretching force and the ultrasonic sound after unloading;
s6: judging whether the actual tensioning efficiency is smaller than a tensioning efficiency threshold value, if so, executing a step S7, and if not, completing the tensioning of the screw;
s7: and tensioning the screw rod to the designed tensioning force by using the feed-through tensioning device, enhancing the tightening degree of a fastening nut at the tensioning end of the screw rod, and returning to the step S4.
On the basis of the scheme, the actual tensioning efficiency of the screw is calculated according to a formula
The calculation is carried out according to the calculation,
wherein, Delta S1Is the difference value of the ultrasonic sound time after the screw rod is unloaded and the ultrasonic sound time before the tension, delta S2The difference value between the ultrasonic sound when the screw rod is stretched to the designed tension force and the ultrasonic sound before stretching.
Compared with the prior art, the invention has the advantages that: the device can accurately identify the axial force loss caused by the retraction of the screw rod by controlling the screw rod tensioning efficiency, realizes that the screw rod is tensioned in place once, avoids the complex processes of detecting and compensating the tensioning for multiple times in the later period, does not need to carry out a complex ultrasonic screw rod calibration experiment in a laboratory, and can effectively improve the tensioning construction quality and the construction efficiency of the suspension bridge cable clamp screw rod.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a suspension bridge cable clamp screw tensioning device in the embodiment of the invention.
Fig. 2 is a flow chart of a method for tensioning a suspension bridge cable clamp screw according to an embodiment of the invention.
In the figure: 1. a nut fastening kit; 11. a pressure-bearing external member; 111. a long round hole; 12. a rotating sleeve member; 121. a circular rotation hole; 2. a feed-through tensioning device; 3. a screw; 4. fixing an anchorage device; 5. an ultrasonic excitation and collection device; 51. an ultrasonic excitation device; 52. an ultrasound acquisition device; 53. an ultrasonic transducer; 54. a signal amplifier; 6. an analysis and control device; 61. a data line; 7. a hydraulic device; 71. a high pressure oil pipe; 8. a cable clamp; 9. the screw fixes the end nut.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Fig. 1 is a schematic structural diagram of a suspension bridge cable clamp screw tensioning device in an embodiment of the present invention, and as shown in fig. 1, the present invention provides a suspension bridge cable clamp screw tensioning device, including: the feed-through type tensioning device 2 is sleeved on the screw rod 3, and one end of the feed-through type tensioning device 2 is abutted against the surface of the cable clamp 8; the screw rod 3 is sleeved with a fixed anchorage device 4, and the fixed anchorage device 4 is abutted against the other end of the through type tensioning device 2; the ultrasonic excitation and acquisition device 5 is connected with the screw 3 and used for exciting the screw 3 and acquiring ultrasonic signals; the device is characterized by further comprising an analysis and control device 6 which is in signal connection with the ultrasonic excitation and acquisition device 5, wherein the analysis and control device 6 is used for sending an ultrasonic excitation instruction, analyzing the ultrasonic sound of the screw 3 before tensioning, when the screw is tensioned to a designed tensioning force and after unloading according to the acquired ultrasonic signals to calculate the tensioning efficiency, determining whether the actual axial force of the screw 3 after tensioning is completed is larger than the designed axial force or not, and sending a tensioning instruction and an unloading instruction to adjust the tensioning degree of the through type tensioning device.
When the device is used, the feed-through tensioning device 2 is arranged between the tensioning end surface of the cable clamp 8 and the fixed anchorage 4, the ultrasonic excitation and acquisition device 5 is connected with the screw rod 3, and the analysis and control device 6 is connected with the ultrasonic excitation and acquisition device 5. Firstly, an ultrasonic excitation and collection device 5 is adopted to carry out ultrasonic excitation and collection on the screw rod 3 before tensioning, and an ultrasonic signal of the screw rod 3 before tensioning is obtained; secondly, stretching the screw rod 3 to a designed tension force by using the through-type stretching device 2, and when the screw rod 3 is stretched to the designed tension force, performing ultrasonic excitation and acquisition on the screw rod 3 by using the ultrasonic excitation and acquisition device 5 to obtain an ultrasonic signal when the screw rod 3 is stretched to the designed tension force; then, tightening a tensioning end nut of the screw 3, unloading the through type tensioning device 2, and carrying out ultrasonic excitation and collection on the unloaded screw 3 to obtain an ultrasonic signal of the unloaded screw 3; and finally, calculating the ultrasonic sound of the screw rod before tensioning, when the screw rod is tensioned to the designed tensioning force and after the tensioning device is unloaded by the analysis and control device 6, calculating the actual tensioning efficiency of the screw rod 3, judging whether the actual tensioning efficiency is less than a tensioning efficiency threshold value, if so, strictly controlling a nut tightening process to enhance the nut tightening degree, and judging whether the actual tensioning efficiency is less than the tensioning efficiency threshold value. If not, tensioning of the screw 3 is completed. The device can accurately identify the axial force loss caused by the retraction of the screw, realizes that the screw is stretched in place once, avoids the complex processes of detecting and supplementing the stretching for many times in the later period, does not need to carry out a complex ultrasonic screw calibration experiment in a laboratory, and can effectively improve the stretching construction quality and the construction efficiency of the suspension bridge cable clamp screw.
Preferably, the ultrasound excitation and acquisition device 5 comprises: an ultrasonic excitation means 51 for emitting an electrical signal for exciting an ultrasonic signal; an ultrasonic acquisition device 52 for acquiring an electric signal converted from the ultrasonic signal; the ultrasonic transducer 53 is arranged at the end part of the screw rod 3 and positioned outside the fixing anchor 4, and the ultrasonic transducer 53 is connected with the ultrasonic excitation device 51 and the ultrasonic acquisition device 52 and is used for converting an electric signal emitted by the ultrasonic excitation device 51 into an ultrasonic signal and converting an ultrasonic signal transmitted in the screw rod 3 into an electric signal.
In the present embodiment, the ultrasonic excitation device 51 is used to emit an electrical signal for exciting an ultrasonic signal, the ultrasonic acquisition device 52 is used to acquire an electrical signal into which an ultrasonic signal is converted, and the ultrasonic transducer 53 is used to convert an electrical signal into an ultrasonic signal or convert an ultrasonic signal into an electrical signal. Such a design can make the user obtain the ultrasonic signal of screw rod fast for the use of calculating actual tensioning efficiency.
Preferably, the ultrasound excitation and acquisition device 5 further comprises a signal amplifier 54, which is arranged between the ultrasound transducer 53 and the ultrasound acquisition device 52, for amplifying the electrical signal emitted by the ultrasound transducer 53.
In the present embodiment, the signal amplifier 54 is used to amplify the electrical signal emitted from the ultrasonic transducer 53, which is more beneficial for the ultrasonic acquisition device 52 to acquire the ultrasonic signal with higher signal-to-noise ratio.
The analysis and control device 6 comprises an ultrasonic analysis module and a control module; the ultrasonic analysis module consists of a filtering module, a noise reduction module and an acoustic time difference calculation module; the control module comprises an ultrasonic control module and a tension control module; the analysis and control device 6 is connected with the ultrasonic acquisition device 52 and the ultrasonic excitation device 51 through a data line 61; the ultrasonic signals acquired by the ultrasonic acquisition device 52 are stored on the analysis and control device 6, and are calculated and analyzed through an ultrasonic analysis module; the ultrasonic control module is used for sending an ultrasonic excitation instruction and an ultrasonic acquisition instruction so as to excite and acquire ultrasonic signals in the screw; the tensioning control module is used for sending a tensioning instruction and an unloading instruction so as to adjust the tensioning degree of the through type tensioning device 2.
Preferably, the system further comprises a hydraulic device 7 connected with the through-type tensioning device 2 and used for providing hydraulic pressure for the through-type tensioning device 2, wherein the hydraulic device 7 is connected with the analysis and control device 6, and the tension and unloading commands sent by the analysis and control device 6 are executed by adjusting the tension degree of the through-type tensioning device 2.
Preferably, the analysis and control device 6 and the hydraulic device 7 each comprise a wireless transmission device for connecting the analysis and control device and the hydraulic device to transmit the tension command and the unloading command sent by the analysis and control device 6 to the hydraulic device 7 for execution.
On the basis of the scheme, the analysis and control device 6 and the hydraulic device 7 can be matched with a plurality of sets of the penetrating type tensioning devices 2, the fixed anchorage devices 4, the nut fastening kit 1 and the ultrasonic excitation and acquisition device 5 for use, so that synchronous tensioning of a plurality of screw rods 3 is realized.
In addition, the feed-through tensioning device 2 is a feed-through hydraulic jack. When the nut fastening kit 1 is not used, other pressure-bearing structures can be adopted to be arranged on the outer side of the fastening nut, one end of the pressure-bearing structure is abutted against the surface of the cable clamp 8, and the other end of the pressure-bearing structure is abutted against one end of the feed-through tensioning device 2. The cable clamp 8 is clamped between the fastening nut and the screw fixing end nut 9, and the pressure bearing structure is provided with a hollowed-out part which can go deep into a fastening tool to screw the fastening nut.
In this embodiment, the ultrasonic transducer 53 is an integral piezoelectric ultrasonic transducer, and an annular magnet is disposed outside the ultrasonic transducer 53 and used for being adsorbed on an end surface of the screw rod. In this embodiment, the ring magnet is attached to the end face of the screw rod, which facilitates the installation of the ultrasonic transducer 53.
Preferably, the device further comprises a nut fastening sleeve 1 which is used for being sleeved on a fastening nut at the tensioning end of the screw rod 3, and the feed-through tensioning device 2 is abutted against the surface of the cable clamp 8 through the nut fastening sleeve 1. In the present embodiment, after the through-type tensioning device 2 is tensioned to the designed tensioning force, the fastening nut at the tensioning end of the screw 3 is tightened by the nut fastening kit 1.
Preferably, the nut fastening sleeve 1 includes a pressure-bearing sleeve 11 and a rotation sleeve 12 capable of rotating relatively, the pressure-bearing sleeve 11 is sleeved on the rotation sleeve 12, the inner hole shape of the rotation sleeve 12 is the same as the outer shape of the fastening nut and is used for being sleeved on the fastening nut of the screw rod 3, the pressure-bearing sleeve 11 is provided with long round holes 111 at intervals in the circumferential direction so as to facilitate the rotation of the rotation sleeve 12, circular rotation holes 121 are provided at intervals in the circumferential direction of the rotation sleeve 12, the circular rotation holes 121 are inserted into the steel rod to rotate the rotation sleeve 12 so as to tighten the fastening nut of the screw rod 3.
In this embodiment, the shape of the inner hole of the rotating sleeve 12 is the same as the external shape of the fastening nut, two ends of the pressure-bearing sleeve respectively abut against the surface of the cable clamp 8 and the end surface of the feed-through tensioning device 2, so that the feed-through tensioning device 2 tensions the screw rod 3, and the rotating sleeve 12 is rotated by inserting a steel rod into the circular rotating hole 121 to tighten the fastening nut of the screw rod 3, and the long circular holes 111 are arranged at intervals in the circumferential direction of the pressure-bearing sleeve 11 to facilitate the rotation of the rotating sleeve 12.
Fig. 2 is a flowchart of a method for tensioning a suspension bridge cable clamp screw according to an embodiment of the present invention, and as shown in fig. 2, the present invention further provides a method for tensioning a suspension bridge cable clamp screw, including the following steps:
s1: calculating a tensioning efficiency threshold value according to the design tensioning force and the design axial force of the screw 3 to be tensioned;
s2: before tensioning, carrying out ultrasonic excitation and collection on the screw rod 3 to obtain ultrasonic sound before tensioning the screw rod 3;
s3: tensioning the screw rod to a designed tension force by using the feed-through tensioning device 2, tightening a fastening nut at the tensioning end of the screw rod 3, and performing ultrasonic excitation and collection on the screw rod 3 tensioned to the designed tension force to obtain ultrasonic sound of the screw rod 3 tensioned to the designed tension force;
s4: unloading the feed-through tensioning device 2, and carrying out ultrasonic excitation and acquisition on the unloaded screw 3 to obtain the ultrasonic sound of the unloaded screw 3;
s5: calculating the actual stretching efficiency of the screw 3 according to the ultrasonic sound before stretching the screw 3, the ultrasonic sound when stretching to the designed stretching force and the ultrasonic sound after unloading;
s6: judging whether the actual tensioning efficiency is smaller than a tensioning efficiency threshold value, if so, executing a step S7, and if not, completing tensioning of the screw 3;
s7: and (5) tensioning the screw rod to the designed tensioning force by using the feed-through tensioning device 2, enhancing the tightening degree of the fastening nut at the tensioning end of the screw rod 3, and returning to the step (S4).
According to the method, by controlling the screw tensioning efficiency, the axial force loss caused by the retraction of the screw can be accurately identified, the screw can be tensioned in place at one time, the complex processes of later-stage detection and tensioning compensation are avoided, a complex ultrasonic screw calibration experiment is not required in a laboratory, and the tensioning construction quality and the construction efficiency of the suspension bridge cable clamp screw can be effectively improved.
In this embodiment, the screw rod can be tensioned to the designed tension force by the through-type tensioning device 2, and the tensioning end nut of the screw rod 3 can be screwed by the nut fastening sleeve 1, so that the screwing degree of the nut can be enhanced by increasing the rotation angle of the rotation sleeve 12.
The tensioning process of the screw 3 comprises the following steps that firstly, one end of the feed-through tensioning device 2 is propped against the fixed anchorage device 4, and the other end of the feed-through tensioning device is propped against the surface of the tensioning end of the cable clamp 8; then, the through-center type tensioning device 2 is pressurized to make the screw rod 3 reach the designed tensile force, at the moment, as the screw rod 3 extends, the nut at the tensioning end of the screw rod is loosened, and the screw rod 3 can be tightened to fasten the nut by inserting the steel rod into the circular rotating hole 121 to rotate the rotating sleeve 12. And finally, unloading the through type tensioning device 2 to complete the tensioning of the screw. The fixing anchor 4 is a nut with internal threads and is fixed at the end part of the screw rod 3.
Preferably, the threshold value of the tensioning efficiency of the screw 3 is according to the formula
Calculation of where P1Designing the axial force, P, for the screw 32The tension is designed for the screw 3.
Preferably, the actual tensioning efficiency of the screw 3 is according to the formula
Calculation of, wherein Δ S1Is the difference value delta S between the ultrasonic sound time after the screw 3 is unloaded and the ultrasonic sound time before tensioning2The difference value between the ultrasonic sound when the screw rod 3 is stretched to the designed stretching force and the ultrasonic sound before stretching.
The principle of the method is as follows:
according to the acoustic elastic effect, the screw axial force and the longitudinal wave velocity have a linear corresponding relation, and the screw axial force can be identified by measuring the acoustic time change. According to the existing theory, considering the influence of temperature and elastic elongation of the screw, the axial force of the screw to be measured can be calculated by the formula (1)
Wherein E is the elastic modulus of the screw, A is the cross section area of the screw, and L0For holding the length of the screw, KSIs the stress coefficient, KTIs a temperature coefficient,. DELTA.S-S0When the time difference is sound, S is the real sound of the screw rod, S0When the screw is unstressed, Δ T is the amount of change in screw temperature.
In the process of stretching the screw, the elastic modulus E, the cross section area A of the screw and the clamping length L of the screw0Stress coefficient KSTemperature coefficient KTThere is no change, and the temperature change Δ T is almost negligible, so the screw tensioning efficiency η is expressed by equation (2):
wherein, Delta S1The difference value delta S between the real sound measurement time of the screw after the tensioning device is unloaded and the real sound measurement time of the screw before tensioning2And the difference value between the real sound measurement time of the screw when the screw is stretched to the designed stretching force and the real sound measurement time of the screw before stretching.
Before the whole method is carried out, the axial force P is firstly designed according to the screw1And design tension force P2The tensioning efficiency threshold η may be calculated0，η0Represented by formula (3):
that is, when the screw tensioning efficiency is η < η0When the real axial force of the retracted screw is smaller than the designed axial force and does not meet the design requirement, the screwing degree of the nut needs to be enhanced, the retraction of the screw is reduced, the tensioning efficiency is improved, and when the tensioning efficiency η of the screw is more than or equal to η0And in the process, the real axial force of the retracted screw is not less than the designed axial force, so that the design requirement is met, and the screw tensioning is finished.
And considering the frequency difference of the screw rod acoustic elastic effect, the actually measured signal is subjected to band-pass filtering. Meanwhile, in order to improve the signal-to-noise ratio of the signal, wavelet denoising is carried out on the filtered ultrasonic signal.
The method is adopted to stretch the cable clamp screw of a certain suspension bridge, and the design axial force P of the screw1750kN, design tension P21050kN, 1080mm long, 48.75mm diameter, 209GPa elastic modulus E, 7830kg/m density ρ3。
Firstly, the axial force P is designed according to the screw1And design tension force P2Computing a tensioning efficiency threshold η071.43 percent. Secondly, before tensioning, ultrasonic excitation and collection are carried out on the screw rod to be tensioned, and an actually measured ultrasonic signal is obtained. Then, the screw is stretched to the designed tension force, namely 1050kN, the screw stretched to the designed tension force is subjected to ultrasonic excitation and collection to obtain an actually measured ultrasonic signal, and the sound time difference delta S is calculated by adopting a cross-correlation method23.987 mus. Finally, the screw nut is screwed down, the tensioning device is unloaded, and the screw rod unloaded by the tensioning device is subjected toUltrasonic excitation and collection are carried out to obtain actually measured ultrasonic signals, and the acoustic time difference delta S is calculated by adopting a cross-correlation method1The actual stretching efficiency η of the screw is 63.13% calculated as 2.517 mu s, and the actual stretching efficiency η of the screw is smaller than the stretching efficiency threshold η0And considering that the actual axial force after the screw rod retracts is smaller than the designed axial force and does not meet the design requirement. Therefore, it is required to improve the screw tensioning efficiency.
The screw was retightened to the design tension, i.e. 1050 kN. By increasing the angle of rotation of the rotating sleeve 12, the nut is tightened to a sufficient extent and the tensioning device is then unloaded. Carrying out ultrasonic excitation and collection on the screw rod unloaded by the tensioning device to obtain an actually measured ultrasonic signal, and calculating the acoustic time difference delta S by adopting a cross-correlation method1Calculating to obtain the actual tensioning efficiency η of the screw to 94.21% in 3.756 mus, wherein the actual tensioning efficiency η of the screw is greater than the tensioning efficiency threshold η0And considering that the actual axial force after the screw rod retracts is larger than the designed axial force, and completing the tensioning of the screw rod.
The result shows that the method provided by the invention can effectively control the axial force loss of the screw rod caused by retraction in the tensioning process, and ensure that the real axial force of the screw rod can meet the design requirement after the tensioning is finished.
In the description of the present application, it should be noted that the terms "upper", "lower", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are only for convenience in describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and operate, and thus, should not be construed as limiting the present application. Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are intended to be inclusive and mean, for example, that they may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.
It is noted that, in the present application, relational terms such as "first" and "second", and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The above description is merely exemplary of the present application and is presented to enable those skilled in the art to understand and practice the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. The utility model provides a suspension bridge cable clamp screw rod tensioning equipment which characterized in that includes:
the feed-through tensioning device (2) is sleeved on the screw (3), and one end of the feed-through tensioning device (2) is abutted against the surface of the cable clamp (8);
the fixed anchorage device (4) is sleeved on the screw rod (3), and the fixed anchorage device (4) abuts against the other end of the through type tensioning device (2);
an ultrasonic excitation and acquisition device (5) which is used for connecting with the screw (3) and exciting the screw (3) and acquiring ultrasonic signals;
the analysis and control device (6) is connected with the ultrasonic excitation and collection device (5), the analysis and control device (6) is used for sending an ultrasonic excitation and collection instruction and analyzing the ultrasonic sound of the screw (3) before tensioning, when the screw is tensioned to a designed tensioning force and after unloading according to collected ultrasonic signals so as to calculate the tensioning efficiency, determine whether the actual axial force of the screw (3) is greater than the designed axial force after tensioning is completed, and send the tensioning instruction and the unloading instruction so as to adjust the tensioning degree of the through type tensioning device (2).
2. A suspension bridge cable clamp screw tensioning device according to claim 1, characterised in that the ultrasonic excitation and acquisition device (5) comprises:
an ultrasonic excitation device (51) for emitting an electrical signal for exciting an ultrasonic signal;
an ultrasound acquisition device (52) for acquiring an electrical signal into which an ultrasound signal is converted;
the ultrasonic transducer (53) is arranged at the end of the screw (3) and positioned outside the fixed anchorage device (4), and the ultrasonic transducer (53) is connected with the ultrasonic excitation device (51) and the ultrasonic acquisition device (52) and is used for converting an electric signal emitted by the ultrasonic excitation device (51) into an ultrasonic signal and converting an ultrasonic signal propagated in the screw (3) into an electric signal;
and the signal amplifier (54) is arranged between the ultrasonic transducer (53) and the ultrasonic acquisition device (52) and is used for amplifying the electric signal emitted by the ultrasonic transducer (53).
3. A tension device for a suspension bridge cable clamp screw rod according to claim 2, wherein the ultrasonic transducer (53) is a piezoelectric ultrasonic transducer integrated with a transceiver, and a ring magnet is arranged outside the ultrasonic transducer (53) and used for being adsorbed on the end surface of the screw rod.
4. A suspension bridge cable clamp screw tensioning device according to claim 1, further comprising a nut tightening sleeve (1) for fitting over a tightening nut at the tensioning end of the screw (3), the feed-through tensioning device (2) being held against the surface of the cable clamp (8) by the nut tightening sleeve (1).
5. A suspension bridge cable clamp screw tensioning device according to claim 4, characterized in that the nut fastening sleeve (1) comprises a pressure-bearing sleeve (11) and a relatively rotatable rotation sleeve (12), the pressure-bearing sleeve (11) is sleeved on the rotation sleeve (12), the rotation sleeve (12) is sleeved on the screw (3) fastening nut, the pressure-bearing sleeve is provided with long circular holes (111) at intervals in the circumferential direction, the rotation sleeve (12) is provided with circular rotation holes (121) at intervals in the circumferential direction, and a steel bar is inserted into the circular rotation holes (121) to rotatably rotate the rotation sleeve (12) so as to tighten the fastening nut on the screw (3).
6. A suspension bridge cable clamp screw tensioning device according to claim 1, further comprising hydraulic means (7) connected to the feed-through tensioning device (2) for providing hydraulic pressure to the feed-through tensioning device (2) to adjust the degree of tensioning of the feed-through tensioning device (2).
7. A suspension bridge cable clamp screw tensioning device according to claim 6, characterized in that the analysis and control device (6) and the hydraulic device (7) each comprise wireless transmission means for connecting the analysis and control device and the hydraulic device to transmit the tensioning and unloading commands issued by the analysis and control device (6) to the hydraulic device (7) for execution.
8. A device for tensioning the screws of a suspension bridge cable clamp according to claim 7, characterized in that said analysis and control means (6) and said hydraulic means (7) can be used in conjunction with a plurality of sets of said feed-through tensioning means (2), of fixed anchors (4) and of ultrasound excitation and acquisition means (5) to achieve the simultaneous tensioning of a plurality of screws.
9. A tensioning method using the suspension bridge cable clamp screw tensioning device according to claim 1, characterized by comprising the steps of:
s1: calculating a tensioning efficiency threshold value according to the design tensioning force and the design axial force of the screw (3) to be tensioned;
s2: before tensioning, carrying out ultrasonic excitation and collection on the screw (3) to obtain ultrasonic sound of the screw (3) before tensioning;
s3: tensioning the screw rod to a designed tension force by using the feed-through tensioning device (2), tightening a fastening nut at the tension end of the screw rod (3), and performing ultrasonic excitation and collection on the screw rod (3) tensioned to the designed tension force to obtain ultrasonic sound of the screw rod (3) tensioned to the designed tension force;
s4: unloading the through type tensioning device (2), and carrying out ultrasonic excitation and acquisition on the unloaded screw (3) to obtain the ultrasonic sound of the unloaded screw (3);
s5: calculating the actual stretching efficiency of the screw (3) according to the ultrasonic sound before stretching the screw (3), the ultrasonic sound when stretching to the designed stretching force and the ultrasonic sound after unloading;
s6: judging whether the actual tensioning efficiency is smaller than a tensioning efficiency threshold value, if so, executing a step S7, and if not, completing the tensioning of the screw (3);
s7: and (5) tensioning the screw rod to the designed tensioning force by using the feed-through tensioning device (2), enhancing the tightening degree of a fastening nut at the tensioning end of the screw rod (3), and returning to the step (S4).
10. A method for tensioning a suspension bridge cable clamp screw according to claim 9, characterized in that the actual tensioning efficiency of said screw (3) is according to the formula
The calculation is carried out according to the calculation,
wherein, Delta S1Is the difference value delta S between the ultrasonic sound time after the screw (3) is unloaded and the ultrasonic sound time before the tension2The difference value between the ultrasonic sound when the screw rod (3) is stretched to the designed tension force and the ultrasonic sound before stretching.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010419701.4A CN111535195A (en) | 2020-05-18 | 2020-05-18 | Suspension bridge cable clamp screw tensioning device and method |
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| CN202010419701.4A CN111535195A (en) | 2020-05-18 | 2020-05-18 | Suspension bridge cable clamp screw tensioning device and method |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112227208A (en) * | 2020-09-23 | 2021-01-15 | 中铁大桥局集团有限公司 | Monitoring and forecasting method for construction period and operation period of suspension bridge cable clamp screw |
| CN113340510A (en) * | 2021-05-21 | 2021-09-03 | 中铁大桥局集团有限公司 | High-strength screw fastening detection device and fastening detection method thereof |
| CN115030065A (en) * | 2022-06-22 | 2022-09-09 | 广东长大道路养护有限公司 | Fastening construction method for cable clamp of suspension bridge |
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2020
- 2020-05-18 CN CN202010419701.4A patent/CN111535195A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112227208A (en) * | 2020-09-23 | 2021-01-15 | 中铁大桥局集团有限公司 | Monitoring and forecasting method for construction period and operation period of suspension bridge cable clamp screw |
| CN112227208B (en) * | 2020-09-23 | 2022-03-29 | 中铁大桥局集团有限公司 | Monitoring and forecasting method for construction period and operation period of suspension bridge cable clamp screw |
| CN113340510A (en) * | 2021-05-21 | 2021-09-03 | 中铁大桥局集团有限公司 | High-strength screw fastening detection device and fastening detection method thereof |
| CN115030065A (en) * | 2022-06-22 | 2022-09-09 | 广东长大道路养护有限公司 | Fastening construction method for cable clamp of suspension bridge |
| CN115030065B (en) * | 2022-06-22 | 2023-04-21 | 广东长大道路养护有限公司 | Suspension bridge cable clamp fastening construction method |
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