Bridge sling dry-wet cycle accelerated corrosion test device and test method under stretch-bend coupling effect

Abstract

The invention relates to a bridge sling dry-wet cycle accelerated corrosion test device and test method under the stretch-bending coupling effect in the technical field of bridge component testing. The device comprises a sealing box, a support is arranged in the sealing box, baffles are arranged on the two sides of the support, a plurality of spray heads are arranged on the support, and the spray heads are connected with a corrosive liquid box through a pipeline and a conveying pump; a plurality of bent pipelines for placing bridge sling test pieces are arranged in the sealing box, a plurality of through holes are circumferentially formed in the middle of each bent pipeline to communicate the inside and the outside of the bent pipeline, and connecting plates at two ends of each bent pipeline are fixed on baffles; when the bridge sling test piece is placed in the bent pipeline, one end of the bridge sling test piece is relatively fixed with the baffle through the fixing piece, and the other end is connected with the tension stretching mechanism. According to the device, the corrosion working condition of the bridge sling under the stretch-bend coupling action is simulated through an artificial accelerated corrosion test, so that the corrosion resistance of a bridge sling test piece is more comprehensively evaluated, and the device has important practical application value.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge component testing, and particularly relates to a salt spray test device and test method for accelerating the corrosion of large-size bridge sling specimens. Background Art

[0002] Due to its excellent plasticity and high strength characteristics, steel is widely used in engineering structures such as bridges. To ensure the durability of bridges during long-term use, the engineering community attaches great importance to the atmospheric corrosion resistance of steel. Especially for bridge steel strands, as an important part of the load-bearing structure, their corrosion resistance is directly related to the safety and service life of bridges. Therefore, it is of great significance to study their corrosion behavior in the actual stress environment.

[0003] Currently, the corrosion performance of steel is generally tested by exposing bridge sling specimens to the natural atmosphere for natural corrosion tests. However, the natural corrosion process is relatively slow, often taking several years to obtain reliable data, which is difficult to meet the actual engineering requirements for rapid data acquisition. Therefore, accelerated corrosion tests are widely used. By simulating accelerated corrosion conditions, the test cycle is shortened, facilitating the rapid evaluation of the corrosion resistance of materials.

[0004] In the Chinese patent database, a bridge sling tensile-torsional corrosion fatigue coupling test device and test method are disclosed, with the publication number: CN115493925A, and the publication date: December 20, 2022. This test device includes a corrosion test system and a fatigue test system. The fatigue test system further includes a tension-compression conversion subsystem and a torsion subsystem. Among them, the tension-compression conversion subsystem converts the vertical pressure into vertical tension through a tension-compression conversion device. At the same time, in the torsion subsystem, the wedge block on the upper bearing platform squeezes the wedge block on the lower bearing platform, causing the thrust bearing to drive the lower bearing platform to rotate, and then driving the bridge sling anchored to the lower bearing platform to rotate, achieving the effect of synchronous action of tension and torsion, and realizing the conversion of compressive load into tensile and torsional fatigue loads. It can simulate the chloride salt erosion and synchronous loading of tension and torsion of the steel wires and steel strands of cable-stayed bridge slings, and can also simulate the individual loading of tension and torsion, effectively simulating the real working state of the steel wires and steel strands of cable-stayed bridge slings; it can also simulate the durability test of materials under the coupling action of harmful ion erosion and complex stress of tension and torsion.

[0005] However, the existing accelerated corrosion test equipment is mainly applicable to the testing of small-size bridge sling specimens. For complex large-size bridge sling specimens such as bridge steel strands, the existing equipment is difficult to provide sufficient test space and accurate mechanical environment, especially difficult to effectively simulate their real stress state under the conditions of tension-bending loads. Therefore, developing a system that can be applied to large-size bridge steel strands and can conduct accelerated corrosion tests under tension-bending loads has become an urgent need in the current corrosion testing field. Summary of the Invention

[0006] In view of the deficiencies existing in the above - mentioned technologies, the object of the present invention is to provide a test device and test method for the accelerated corrosion of bridge suspension cables under the combined action of tension and bending during the dry - wet cycle, which can be used for the tests of large - size bridge suspension cable specimens, aiming to solve the problem in the prior art that it is difficult to conduct corrosion tests on large - size and complex - shaped bridge suspension cable specimens under tensile and bending stresses.

[0007] To solve the above - mentioned technical problems, the present invention adopts the following technical solutions: A test device for the accelerated corrosion of bridge suspension cables under the combined action of tension and bending during the dry - wet cycle includes a sealed box. Inside the sealed box, there is a bracket. On both sides of the bracket, there are baffles. On the bracket, there are several spray nozzles. The spray nozzles are connected to a corrosion liquid tank through pipelines and a delivery pump. Inside the sealed box, there are multiple bending pipes for placing bridge suspension cable specimens. Several through - holes are circumferentially arranged in the middle of the bending pipes to connect the inside and outside of the bending pipes. The bending pipes are made of corrosion - resistant and high - strength steel pipes. The two ends of the bending pipes are fixed to connecting plates, and the connecting plates are fixed to the baffles by bolts. Holes for the bridge suspension cable specimens to pass through are provided on the connecting plates and the baffles corresponding to the pipe orifices of the bending pipes. The middle position of the bending pipe is lower than the positions of its two ends' pipe orifices. When the bridge suspension cable specimen is placed in the bending pipe, one end of the bridge suspension cable specimen is relatively fixed to the baffle through a fixing member, and the other end is connected to a tension - stretching mechanism.

[0008] When the device works, the bridge suspension cable specimen is installed in the bending pipe to simulate its working condition under bending stress. The corrosion liquid is sprayed on the surface of the bridge suspension cable specimen through the spray nozzles to simulate the corrosion under actual working conditions through accelerated corrosion. At the same time, tension is applied through the tension - stretching mechanism to simulate the tensile working condition of the bridge suspension cable under actual working conditions. Through a period of dry - wet cycle, the corrosion situation of the large - size bridge suspension cable specimen under the combined action of tension and bending in actual use is simulated. By replacing bending pipes with different curvature radii, the corrosion process under different bending stress working conditions can be simulated. This device can meet the requirements of accelerated corrosion tests for bridge suspension cable specimens of different sizes and shapes, especially the corrosion effect under tensile and bending stresses.

[0009] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0010] 1. It can meet the corrosion test requirements of different types of bridge suspension cable specimens under tensile and bending stresses.

[0011] 2. It shortens the corrosion test cycle and improves the uniformity of corrosion tests.

[0012] 3. By simulating multi - angle corrosion conditions in a complex environment, the corrosion - resistant performance of the bridge suspension cable specimen can be more comprehensively evaluated, which has important practical application value.

[0013] Further, the fixing member is a fixture composed of two half pieces. The two half pieces are clamped at one end of the bridge sling specimen and fastened to the outer periphery of one end of the bridge sling specimen through bolts. The end of the fixture abuts against the outer side of the baffle. A limiting end can be formed through the fixture. When the tension stretching mechanism stretches the bridge sling specimen, the end of the fixture abuts against the outer side of the baffle so that it cannot be pulled out of the bending pipe, thus facilitating the test.

[0014] Further, the whole of the bracket, the bending pipe and the nozzle is wrapped by a sealing film to form a sealed box. The sealing film wraps to form a relatively enclosed space, which ensures that the smoke formed by the spraying of the corrosion solution is not easy to overflow and also avoids the influence of the change of the external environment on the test environment.

[0015] Further, the bracket is spliced by a plurality of grooved steel members with holes through bolts. The bracket includes at least one layer, and rollers are provided at the bottom of the bracket. The grooved steel members can be disassembled and assembled conveniently. The grooved steel members can build a relatively stable space. When the bending pipe is disassembled and assembled, it is used to temporarily carry the bending pipe, which facilitates the replacement of bending pipes with different curvature radii. The setting of the rollers facilitates the movement of the position.

[0016] Further, a bottom plate for fixing to the ground is connected to the bottom of the baffle. The outer side of the baffle and the bottom plate are connected by a reinforcing rib plate, and embedded bolts are provided on the ground and connected to the bottom plate. This structure ensures that the baffle has sufficient load-bearing capacity so as to provide sufficient support strength when stretching the bridge sling specimen.

[0017] Further, a water receiving trough is provided at the bottom inside the sealed box. The water receiving trough can temporarily collect the sprayed corrosion liquid.

[0018] Further, the present invention also provides a method for accelerating the corrosion test of a bridge sling under the coupling action of tension and bending by using the above device, including the following steps:

[0019] Step 1: Fabricate a bridge sling specimen

[0020] Take a plurality of bridge sling specimens of a certain length, retain the high-density polyethylene sheaths at both ends, only strip the high-density polyethylene sheath in the middle of the bridge sling specimen to expose the steel cable part in the middle part, and polish and clean the galvanized anti-corrosion layer on the surface of the steel cable part. At the same time, number the specimens for subsequent observation and record;

[0021] Step 2: Prepare the corrosion solution

[0022] Use a NaCl solution with a mass fraction of 5%. Then add copper chloride dihydrate to the NaCl solution and stir to dissolve it. Control the concentration of copper chloride at 0.26 ± 0.02 g / L. Add CH3COOH dropwise to the solution to adjust the pH value of the solution so that the pH = 3.0 - 3.3 at 25°C. Finally, pour the prepared corrosion solution into the corrosion solution tank.

[0023] Step 3: Installation of the bridge sling specimen

[0024] Insert the bridge sling specimen after Step 1 into the bending pipe through one end of the bending pipe. The bridge sling specimen passes through the other end of the bending pipe. Fix one end of it relative to the baffle, and the other end to the tension stretching mechanism so that it can withstand the tension without being pulled off from one end.

[0025] Step 4: Conduct an artificial accelerated corrosion test

[0026] Start the delivery pump to spray the corrosion solution on the outside of the bending pipe through the nozzle. The corrosion solution passes through the through holes on the bending pipe to wet the surface and inside of the steel wire rope exposed in the middle part, accelerating the corrosion of the steel wire rope. The delivery pump works periodically and intermittently to conduct a wet-dry cycle test on the bridge sling specimen.

[0027] Step 5: Tension the bridge sling specimen

[0028] While conducting a wet-dry cycle test on the bridge sling specimen, apply tensile force to the bridge sling specimen through the tension stretching mechanism.

[0029] Step 6: Simulate different magnitudes of bending stresses applied to the sling specimen

[0030] Replace the bending pipes with different bending angles, and then repeat the above Steps 3 - 5; simulate different magnitudes of bending stresses applied to the sling specimen, and further simulate the tensile and bending stress states of the bridge sling specimen in actual use.

[0031] Step 7: Collect damage information inside the bridge sling specimen for analysis

[0032] During the above working process, continuously collect the damage information inside the sling and record its test conditions and time; after a period of testing, remove the bridge sling specimen to collect and evaluate the final damage information.

[0033] Furthermore, the artificial accelerated corrosion test is divided into 6 test conditions, namely corrosion cycles of 0d, 30d, 60d, 90d, 120d, and 150d.

[0034] Further, in step 5, the sling is tensioned by gradually increasing the tension, and finally the stress of the steel wire of the sling specimen reaches 761 MPa, which is 40% of the designed tensile strength value, so as to simulate the stress level under the actual working condition of the sling, and at the same time record the tension force value and the deformation condition.

[0035] Further, in step 7, a non-destructive testing device, an ultrasonic detector, is used to detect the internal steel wires of the specimen after being subjected to tensile-bending action and corrosion, and record the corrosion degree and fracture condition of the internal steel wires of the specimen. Description of the Drawings

[0036] Figure 1 It is a schematic structural diagram of the present invention.

[0037] Figure 2 It is Figure 1 the view from direction A of

[0038] Figure 3 It is Figure 1 the partial structural schematic diagram of B in , showing the structure of the fixture part.

[0039] In the figure, 1 is the embedded bolt, 2 is the bottom plate, 3 is the baffle, 4 is the bracket, 5 is the connecting plate, 6 is the reinforcing rib plate, 7 is the bent pipe, 7a is the through hole, 8 is the nozzle, 9 is the pipe, 10 is the sealing film, 11 is the fixture, 11a and 11b are half blocks, 11c is the end of the fixture, 12 is the corrosion liquid tank, 13 is the delivery pump, 14 is the water receiving tank, 15 is the roller, 16 is the hole, and 17 is the bridge sling specimen. Detailed Embodiment

[0040] As Figures 1-3 , it is a bridge sling dry-wet cycle accelerated corrosion test device under the coupling action of tension and bending, including a sealed box. There is a bracket 4 inside the sealed box, baffles 3 are arranged on both sides of the bracket 4, and a plurality of nozzles 8 are arranged on the bracket 4. The nozzles 8 are connected to the corrosion liquid tank 12 through pipes 9 and a delivery pump 13; there are a plurality of bent pipes 7 for placing the bridge sling specimen 17 inside the sealed box. A plurality of through holes 7a are circumferentially arranged in the middle of the bent pipe 7 to connect the inside and outside of the bent pipe 7. The bent pipe 7 is a steel pipe with corrosion resistance and high strength; both ends of the bent pipe 7 are fixed to the connecting plate 5, and the connecting plate 5 is fixed to the baffle 3 by bolts. Holes 16 for the bridge sling specimen 17 to pass through are arranged on the connecting plate 5 and the baffle 3 corresponding to the pipe orifices of the bent pipe 7; the middle position of the bent pipe 7 is lower than the positions of the pipe orifices at both ends; when the bridge sling specimen 17 is placed in the bent pipe 7, one end of the bridge sling specimen 17 is relatively fixed to the baffle 3 through a fixing member, and the other end is connected to a tension stretching mechanism.

[0041] The fixing member is a fixture 11 composed of two half pieces 11a and 11b. The two half pieces 11a and 11b are clamped at one end of the bridge sling specimen 17 and fastened to the outer periphery of one end of the bridge sling specimen 17 by bolts. The end 11c of the fixture abuts against the outside of the baffle 3. A limiting end can be formed through the fixture 11. When the tension stretching mechanism stretches the bridge sling specimen 17, the end of the fixture 11 abuts against the outside of the baffle 3 so that it cannot be pulled out from the bending pipe 7, thus facilitating the test.

[0042] The outside of the bracket 4, the bending pipe 7 and the nozzle 8 is integrally wrapped by a sealing film 10 to form a sealed box. The sealing film 10 wraps to form a relatively enclosed space, ensuring that the smoke formed by the spraying of the corrosive solution is not easily spilled and also avoiding the influence of changes in the external environment on the test environment. The sealed box can also be made of rigid plates.

[0043] The bracket 4 is spliced by a plurality of grooved steel members with holes through bolts. The bracket 4 includes at least one layer, and rollers 15 are provided at the bottom of the bracket 4. The grooved steel members can be disassembled and assembled conveniently. The grooved steel members can build a relatively stable space and are used to temporarily carry the bending pipe 7 when the bending pipe 7 is disassembled and assembled, facilitating the replacement of the bending pipe 7 with different curvature radii. The setting of the rollers 15 facilitates the movement of the position.

[0044] A bottom plate 2 for fixing to the ground is connected to the bottom of the baffle 3. The outside of the baffle 3 and the bottom plate 2 are connected by a reinforcing rib plate 6, and embedded bolts 1 are provided on the ground and connected to the bottom plate 2. This structure ensures that the baffle 3 has sufficient load-bearing capacity to provide sufficient support strength when stretching the bridge sling specimen 17.

[0045] A water receiving tank 14 is provided at the bottom inside the sealed box. The water receiving tank 14 can temporarily collect the sprayed corrosive liquid.

[0046] When the device works, the bridge sling specimen is installed in the bending pipe to simulate its working condition under bending stress; the corrosive liquid is sprayed on the surface of the bridge sling specimen through the nozzle to simulate the corrosion under actual working conditions by accelerating corrosion; at the same time, tension is applied through the tension stretching mechanism to simulate the tensile working condition of the bridge sling under actual working conditions; through a period of wet-dry cycle, the corrosion situation of the large-size bridge sling specimen under the combined action of tension and bending in actual use is simulated. Replacing the bending pipe with different curvature radii can simulate the corrosion process under different bending stress working conditions. The device can meet the requirements of the accelerated corrosion test of bridge sling specimens of different sizes and shapes, especially the corrosion effect under tensile and bending stresses.

[0047] Specifically, the method for the accelerated corrosion test of the bridge sling under the combined action of tension and bending using the above device includes the following steps:

[0048] Step 1: Fabricate the bridge sling specimen

[0049] Take multiple specimens of bridge sling with a certain length, retain the high-density polyethylene sheaths at both ends, only strip the high-density polyethylene sheath in the middle of the bridge sling specimen to expose the wire rope part in the middle, and polish and clean the galvanized anti-corrosion layer on the surface of the wire rope part. At the same time, number the specimens for subsequent observation and recording. Specifically, the total length of the sheath of the test sling specimen is 100 cm and the thickness is 10 mm. To simulate the influence of local corrosion in the actual service environment of the sling, strip out the 30-cm high-density polyethylene (HDPE) sheath in the middle of the sling specimen, retain 35-cm sheaths on both sides, and seal the cut.

[0050] Step 2: Prepare the corrosion solution

[0051] Use a 5% mass fraction of NaCl solution, then add copper dichloride dihydrate to the NaCl solution and stir to dissolve it. Control the concentration of copper dichloride at 0.26 ± 0.02 g / L. Add CH3COOH dropwise to the solution to adjust the pH value of the solution so that the pH = 3.0 - 3.3 at 25°C. Finally, pour the prepared corrosion solution into the corrosion solution tank.

[0052] Step 3: Install the bridge sling specimen

[0053] Insert the bridge sling specimen after Step 1 into the bending pipe through one end of the bending pipe, and the bridge sling specimen passes through the other end of the bending pipe. Fix one end of it relative to the baffle, and the other end to the tension stretching mechanism so that it can withstand tension without being pulled off from one end.

[0054] Step 4: Conduct the artificial accelerated corrosion test

[0055] Start the delivery pump to spray the corrosion solution on the outside of the bending pipe through the nozzle. The corrosion solution passes through the through holes on the bending pipe to wet the surface and inside of the exposed wire rope in the middle part, and accelerate the corrosion of the wire rope. The delivery pump works periodically and intermittently to conduct a dry-wet cycle test on the bridge sling specimen. The artificial accelerated corrosion test is divided into 6 test conditions, namely corrosion cycles of 0 d, 30 d, 60 d, 90 d, 120 d, and 150 d. The test conditions are shown in Table 1 below.

[0056] Table 1 Details of the corrosion conditions of the sling accelerated corrosion test

[0057]

[0058] Step 5: Tension the bridge sling specimen

[0059] While conducting the dry-wet cycling test on the bridge sling specimen, a tensile force is applied to the bridge sling specimen through a tension stretching mechanism; the tension of the sling can be increased step by step, and finally the stress of the steel wire of the sling specimen reaches 761 MPa, which is 40% of the designed tensile strength value, so as to simulate the stress level of the sling under the real working condition, and at the same time record the tension force value and the deformation condition.

[0060] Step 6: Simulate different magnitudes of bending stress applied to the bridge sling specimen

[0061] Replace the bending pipes with different bending angles, and then repeat the above steps 3-5; simulate different magnitudes of bending stress applied to the bridge sling specimen, and further simulate the tensile and bending stress states of the bridge sling specimen during actual use; the bending angle of the bending pipe is the circular arc angle corresponding to the bending pipe.

[0062] Table 2 Details of the load conditions of the bridge sling specimen under the coupling action of tension and bending

[0063]

[0064] Step 7: Collect the damage information inside the bridge sling specimen for analysis

[0065] During the above working process, continuously collect the damage information inside the sling and record its test conditions and time; using the above experimental steps, the corrosion rates of some working conditions of the bridge sling specimen in the dry-wet cycling corrosion test are shown in Table 3 below. The specific working condition is that the corrosion liquid is sprayed twice a day, each time for 2 hours, and the collected corrosion liquid after corrosion is discarded, and the rest of the time is the waiting time; the load conditions and the bending angles of the bending pipes in Table 3 correspond one by one to those in Table 2. After a period of testing, remove the bridge sling specimen to collect and evaluate the final damage information. Use the non-destructive testing equipment ultrasonic detector to detect the internal steel wires of the specimen after being subjected to tensile and bending actions and corrosion, and record the corrosion degree and fracture condition of the internal steel wires of the specimen.

[0066] Table 3 Corrosion rates of some working conditions of the bridge sling specimen in the corrosion test

[0067]

[0068] In the above table, after 30, 60, and 90 days of corrosion, the corrosion rates have obvious changes, effectively simulating the accelerated corrosion of the bridge sling specimen under the action of tension and bending and in the corrosion environment. The above tests are obtained through different specimens under different working conditions. During the test process, it can also be obtained by using the same specimen after gradually increasing the tension to 761 MPa.

[0069] In summary, through a test scheme with reasonable structure and innovative design, the present invention can effectively solve the difficulties encountered in the corrosion test of large-size and complex-shaped bridge sling specimens in the prior art, ensure that the bridge sling specimens can conduct real and effective accelerated corrosion tests under the action of tension and bending and in a corrosive environment, and meet different test requirements.

[0070] The present invention is not limited to the above embodiments. Based on the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and deformations to some technical features without creative labor according to the disclosed technical content, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. An accelerated corrosion test device for bridge slings under the combined action of tension and bending and wet-dry cycles, characterized in that: It includes a sealed box, in which there is a bracket. There are baffles on both sides of the bracket, and several spray heads are arranged on the bracket. The spray heads are connected to a corrosion liquid tank through pipelines and a delivery pump; there are multiple bending pipelines for placing bridge sling specimens in the sealed box. A number of through holes are circumferentially arranged in the middle of the bending pipeline to connect the inside and outside of the bending pipeline. The bending pipeline is a steel pipeline with corrosion resistance and high strength; both ends of the bending pipeline are fixed to a connecting plate, and the connecting plate is fixed to the baffle by bolts. Holes for the bridge sling specimen to pass through are arranged on the connecting plate and the baffle corresponding to the pipe orifices of the bending pipeline; the middle position of the bending pipeline is lower than the positions of its two ends' pipe orifices; when the bridge sling specimen is placed in the bending pipeline, one end of the bridge sling specimen is relatively fixed to the baffle through a fixing member, and the other end is connected to a tension stretching mechanism.

2. The accelerated corrosion test device for bridge slings under the coupling action of tension and bending and dry-wet cycling according to claim 1, wherein: The fixing member is a clamp composed of two half blocks. The two half blocks clamp one end of the bridge sling specimen and are fastened to the outer periphery of one end of the bridge sling specimen by bolts. The end of the clamp abuts against the outside of the baffle.

3. The accelerated corrosion test device for bridge sling under the coupling action of tension and bending and wet-dry cycle according to claim 1, wherein: The whole of the bracket, the bending pipeline and the spray heads is wrapped by a sealing film to form a sealed box.

4. The accelerated corrosion test device for bridge slings under the coupling action of tension and bending and wet-dry cycles according to claim 1, characterized in that: The bracket is spliced by a number of channel steel members with holes through bolts. The bracket includes at least one layer, and rollers are arranged at the bottom of the bracket.

5. The accelerated corrosion test device for bridge sling under the coupling action of tension and bending and dry-wet cycle according to claim 1, characterized in that: The bottom of the baffle is connected to a bottom plate for fixing to the ground. The outside of the baffle and the bottom plate are connected by reinforcing rib plates, and embedded bolts are arranged on the ground and connected to the bottom plate.

6. The accelerated corrosion test device for bridge slings under the combined action of tension and bending and wet-dry cycles according to claim 1, characterized in that: A water receiving tank is arranged at the bottom inside the sealed box.

7. A method for accelerating the corrosion test of bridge slings under the combined action of tension and bending and wet-dry cycles by using the device according to any one of claims 1-6, characterized in that, It includes the following steps: Step 1: Fabricate bridge sling specimens Take multiple bridge sling specimens of a certain length, retain the high-density polyethylene sheaths at both ends, only strip the high-density polyethylene sheath in the middle of the bridge sling specimen to expose the steel cable part in the middle, polish and clean the galvanized anti-corrosion layer on the surface of the steel cable part, and number the specimens at the same time for subsequent observation and recording; Step 2: Prepare the corrosion solution Use a 5% mass fraction of NaCl solution, then add copper dichloride dihydrate to the NaCl solution, stir and dissolve it. The concentration of copper dichloride is controlled at 0.26±0.02 g / L. Then add CH3COOH dropwise to the solution to adjust the acidity and alkalinity of the solution so that the pH of the solution at 25°C is 3.0 - 3.3; finally, pour the prepared corrosion solution into the corrosion liquid tank. Step 3: Install the bridge sling specimens Insert the bridge sling specimens after Step 1 into the bending pipeline through one end of the bending pipeline. The bridge sling specimens pass through the other end of the bending pipeline. Fix one end of it to the baffle relatively, and the other end to the tension stretching mechanism so that it can bear the tension and will not be pulled off from one end. Step 4: Conduct an artificial accelerated corrosion test Start the delivery pump to spray the corrosion solution on the outside of the bending pipeline through the spray heads. The corrosion solution passes through the through holes on the bending pipeline to wet the surface and inside of the exposed steel cable part in the middle, and accelerate the corrosion of the steel cable; the delivery pump works periodically and intermittently to conduct a wet-dry cycle test on the bridge sling specimens; Step 5: Tension the bridge sling specimens While conducting a wet-dry cycle test on the bridge sling specimens, apply tensile force to the bridge sling specimens through the tension stretching mechanism; Step 6: Simulate different magnitudes of bending stresses applied to the sling specimens Replace the curved pipe with different bending angles, and then repeat the above steps 3-5; simulate the bending stress of different magnitudes applied to the sling specimen, and then simulate the tensile bending stress state of the bridge sling specimen in actual use; Step 7: Collect damage information inside the bridge cable specimen for analysis During the above work process, the damage information inside the cable is continuously collected and the test conditions and time are recorded; after a period of testing, the bridge cable specimens are removed to collect and evaluate the final damage information.

8. The accelerated corrosion test method for bridge slings under the combined action of tension and bending during dry-wet cycles according to claim 7, wherein The artificial accelerated corrosion test is divided into 6 test conditions, namely corrosion cycles of 0d, 30d, 60d, 90d, 120d and 150d.

9. The accelerated corrosion test method for bridge slings under the combined action of tension and bending during dry-wet cycles according to claim 7, characterized in that In step 5, the tension of the sling is increased step by step, and finally the stress of the steel wire of the sling specimen reaches 761MPa, which is 40% of the design value of tensile strength, so as to simulate the stress level of the sling under the actual working condition, and the tensioning force and deformation are recorded at the same time.

10. The accelerated corrosion test method for bridge slings under the combined action of tension and bending during dry-wet cycles according to claim 7, characterized in that In step 7, an ultrasonic detector, which is a non-destructive testing device, is used to test the steel wire inside the specimen after being subjected to tension, bending and corrosion, and to record the degree of corrosion and fracture of the steel wire inside the specimen.

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