An equivalent conversion method for accelerated corrosion of bridge cables

Abstract

The invention discloses an equivalent conversion method for accelerated corrosion of bridge cables, which includes inferring the influence functions of corrosion parameters such as temperature T, humidity RH, chloride ion concentration and sulfate ion concentration on corrosion current based on the equivalent electrochemical conversion principle of metal material corrosion, applying the functions to the accelerated corrosion test environment and the target bridge site corrosion environment to respectively calculate the corrosion quantity Q, and calculating the equivalent conversion coefficient α based on the corrosion damage equivalence principle; the scheme proposes a reasonable equivalent relationship for the accelerated corrosion test of bridge cables, and provides reliable technical support for the safety and durability performance evaluation of large cable bridges.

Description

Technical Field

[0001] The invention relates to the technical field of bridge cable corrosion equivalent, and in particular to an equivalent conversion method for accelerated corrosion of bridge cables. Background Art

[0002] Bridge cables are important load-bearing components of cable-bearing bridges, and their safety and durability directly affect the safety of bridge structures. However, due to the complex and changeable service environment of bridges, the cables are often corroded, which affects the safety of bridge operations. Accelerated corrosion tests are needed to study the corrosion resistance of bridge cables. However, the existing equivalent conversion relationship between the corrosion time in the laboratory accelerated corrosion environment and the service environment of bridge cables is insufficient, and there is no unified conversion standard, which leads to limitations and defects in the evaluation of the corrosion resistance of bridge cables.

[0003] Therefore, it is very necessary to accurately convert the equivalent relationship between the accelerated corrosion test and the bridge service environment based on the laboratory accelerated corrosion test; the existing research on the equivalent conversion method of accelerated corrosion test is mostly based on Faraday's law and is mainly conducted on a single metal material. Although it can convert the accelerated corrosion equivalent, it ignores the influence of environmental corrosion parameters and the characteristics of the two different corrosion stages of the bridge cable metal coating protective layer + steel wire or anchor; therefore, it is urgently needed to take bridge cables as the research object, consider the influence of corrosion environment parameters, and establish an equivalent accelerated corrosion conversion method for bridge cables. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides an equivalent conversion method for accelerated corrosion of bridge cables. The method can take bridge cables as the research object, establish the equivalent accelerated corrosion time conversion relationship between the laboratory accelerated corrosion test and the target bridge site environment, and solve the problem of inaccurate equivalent conversion of accelerated corrosion of bridge cables in the prior art.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is:

[0006] Provided is an equivalent conversion method for accelerated corrosion of bridge cables, which includes inferring the corrosion parameters temperature T, humidity RH, chloride ion concentration based on the electrochemical conversion principle of metal material corrosion equivalent and sulfate ion concentration The influence function on the corrosion current is calculated and applied to the accelerated corrosion test environment and the target bridge site corrosion environment to calculate the corrosion quantity Q respectively. The equivalent conversion coefficient α is calculated based on the corrosion damage equivalence principle. The specific conversion method is:

[0007] S1: According to the corrosion parameters temperature T, humidity RH, chloride ion concentration and sulfate ion concentration The influence of each parameter on the corrosion current I is proposed.

[0008] S2: Based on the function of corrosion current I, corrosion time t and Faraday's law obtained in S1, the corrosion quantity Q of the bridge cable system under the corrosive environment until it corrodes to a fixed level is obtained;

[0009] S3: The bridge cables are divided into the cable metal protective coating corrosion stage and the cable steel wire or anchor corrosion stage according to the corrosion sequence. The corrosion current of the bridge cable protective layer is obtained according to the different specifications of bridge cables, different material properties and the thickness of the metal coating protective layer, which have different effects on the electrochemical corrosion of the bridge cables. lm And the corrosion quantity Q of cable wire or anchor ln ;

[0010] S4: The influencing parameters of the laboratory accelerated corrosion environment, temperature T, humidity RH, chloride ion concentration and sulfate ion concentration Substituting into the function of bridge cable corrosion electricity obtained by S3, the corrosion electricity Q of the metal coating protective layer under the laboratory accelerated corrosion environment is obtained. lsm and the corrosion charge Q of cable wire or anchor lsn ;

[0011] S5: Based on the temperature T, humidity RH, and chloride ion concentration in the target bridge site corrosion environment within the set time period and sulfate ion concentration The fluctuations existing in the environment parameters within the set time period are equivalently converted, and the equivalent parameters of the environmental parameters are obtained. Combined with the function of the corrosion electricity of the bridge cable system under the corrosive environment in S2, the corrosion electricity of the metal coating protective layer under the corrosive environment of the target bridge site is obtained. and corrosion of cable wires or anchors

[0012] S6: According to the principle of corrosion damage equivalence, establish the corrosion quantity Q of the metal coating protective layer of bridge cables under laboratory accelerated corrosion environment lsm Corrosion electricity of metal coating protective layer of bridge cables under target bridge site environment The equivalent relationship of Q and the corrosion quantity Q of bridge cable wire or anchor in the laboratory accelerated corrosion environment lsn Corrosion electricity of bridge cable wire or anchor in target bridge site environment The equivalent relationship between the laboratory accelerated corrosion environment and the target bridge site environment is obtained, that is, the conversion relationship between the corrosion time of the bridge cable metal coating protective layer and the bridge cable steel wire or anchor is obtained, that is, the equivalent conversion coefficient αm and α n , and corrosion equivalent conversion is performed.

[0013] The beneficial effects of the present invention are:

[0014] 1. This scheme proposes an equivalent conversion method for accelerated corrosion of bridge cables, which provides a reasonable reference for the corrosion performance evaluation of bridge cables and provides reliable technical support for the safety and durability performance evaluation of large cable bridges.

[0015] 2. This scheme improves the shortcomings of the existing equivalent conversion method, which does not take into account the impact of the test environment and the service environment and the differences between them, as well as the characteristics of the bridge cable coating and iron steel wire or anchor being divided into two corrosion stages, and can provide support for the evaluation of the corrosion resistance of bridge cables. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Flow chart of the equivalent conversion method for accelerated corrosion of bridge cables.

[0017] Figure 2 Figure 2 is a graph showing the rate curves of the two corrosion stages of bridge cables.

[0018] Figure 3 This is a graph showing the effect of temperature on corrosion current.

[0019] Figure 4 This is a graph showing the effect of humidity on corrosion current.

[0020] Figure 5 This is a graph showing the effect of chloride ions on corrosion current.

[0021] Figure 6 This is a curve diagram showing the effect of sulfate ions on corrosion current. DETAILED DESCRIPTION

[0022] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0023] like Figures 1 to 6 As shown in the figure, the equivalent conversion method of accelerated corrosion of bridge cables in this scheme includes inferring the corrosion parameters temperature T, humidity RH, chloride ion concentration based on the equivalent electrochemical conversion principle of metal material corrosion and sulfate ion concentration The influence function on the corrosion current is calculated and applied to the accelerated corrosion test environment and the target bridge site corrosion environment to calculate the corrosion quantity Q respectively. The equivalent conversion coefficient α is calculated based on the corrosion damage equivalence principle. The specific conversion method is:

[0024] S1: According to the corrosion parameters temperature T, humidity RH, chloride ion concentration and sulfate ion concentration The influence of each parameter on the corrosion current I is proposed. Among them, the function of the influence of environmental corrosion parameters on corrosion current I is specifically:

[0025]

[0026] Where η is the material sensitivity coefficient;

[0027] S2: According to the function of corrosion current I, corrosion time t and Faraday's law obtained in S1, the corrosion quantity Q of the bridge cable system under the corrosive environment is obtained to a fixed level; wherein, the fixed levels of corrosion of the bridge cable system include: Level I, Level II, Level III, Level IV, Level V and Level VI; Level I means that the metal protective coating of the cable has not rusted; Level II means that the metal protective coating of the cable has rusted, and the rust area is less than 5%; Level III means that the rust area of ​​the metal protective coating is greater than or equal to 5% and less than 20%; Level IV means that the rust area of ​​the metal protective coating is greater than or equal to 20%, and the steel wire or anchor is exposed and rusted; Level V means that the cable steel wire or anchor has corrosion pits; Level VI means that groove-shaped rust pits appear on the surface of the cable steel wire or anchor and the steel wire or anchor is broken.

[0028] The corrosion charge Q of the bridge cable is:

[0029]

[0030] S3: The bridge cables are divided into the cable metal protective coating corrosion stage and the cable steel wire or anchor corrosion stage according to the corrosion sequence. The corrosion current of the bridge cable protective layer is obtained according to the different specifications of bridge cables, different material properties and the thickness of the metal coating protective layer, which have different effects on the electrochemical corrosion of the bridge cables. lm And the corrosion quantity Q of cable wire or anchor ln ;

[0031] The corrosion power of bridge cables includes the corrosion power of the metal protective coating of bridge cables Q lm and the corrosion charge Q of cable wire or anchor ln , the formula is:

[0032] Q lm =I m t m (t≤tmmax )

[0033] Q ln =I n t n (t≥t mmax )

[0034] Where, t m is the time for the cable metal protective coating to be corroded; t n is the time when the cable wire or anchor is corroded; t mmax It is the time required for the cable metal protective coating to rust and fail. When the cable metal protective coating is completely corroded, t m =t mmax ; t is the total time of bridge cable corrosion, t = t m +t n ;

[0035] S4: The influencing parameters of the laboratory accelerated corrosion environment, temperature T, humidity RH, chloride ion concentration and sulfate ion concentration Substituting into the function of bridge cable corrosion electricity obtained by S3, the corrosion electricity Q of the metal coating protective layer under the laboratory accelerated corrosion environment is obtained. lsm , and the corrosion charge Q of cable wire or anchor lsn ;

[0036] Among them, the corrosion quantity Q of the cable metal protective coating under the laboratory accelerated corrosion environment is lsm for:

[0037]

[0038] Corrosion quantity Q of cable wire or anchor lsn for:

[0039]

[0040] In the formula, I sm and I sn are the corrosion currents of the cable metal protective coating and cable steel wire or anchor in the laboratory accelerated corrosion environment, η sm and η sn are the material sensitivity coefficients of the cable metal protective coating and cable steel wire or anchor in the laboratory accelerated corrosion environment, t sm and t sn are the corrosion time of cable metal protective coating and cable steel wire or anchor in the laboratory accelerated corrosion environment, T s RH s , and They are the temperature, humidity, chloride ion concentration, and sulfate ion concentration in the laboratory accelerated corrosion environment;

[0041] S5: Based on the temperature T, humidity RH, and chloride ion concentration in the target bridge site corrosion environment within the set time period and sulfate ion concentration The fluctuations existing in the environment parameters within the set time period are equivalently converted, and the equivalent parameters of the environmental parameters are obtained. Combined with the function of the corrosion electricity of the bridge cable system under the corrosive environment in S2, the corrosion electricity of the metal coating protective layer under the corrosive environment of the target bridge site is obtained. and corrosion of cable wires or anchors

[0042] Among them, the calculation method of the equivalent parameters of the corrosion environment parameters under the corrosion environment of the target bridge site is:

[0043] A year is divided into several periods. In each period, the corrosion environment parameters are tested several times and the average value is taken. The equivalent parameters of the corrosion environment parameters are calculated based on the average value. The formula is:

[0044]

[0045] In the formula, is the constant equivalent value of the corrosion environment parameter, that is, the constant equivalent value of the temperature T b , constant equivalent value of humidity RH b , constant equivalent value of chloride ion concentration and a constant equivalent value of sulfate ion concentration One of the following; x i is the average value of the corrosion environment parameter in the ith period; t i is the average value x i Number of occurrences; t 总 is the total number of time periods in the calculation cycle;

[0046] The corrosion quantity of the cable metal protective coating under the corrosion environment of the target bridge site is:

[0047]

[0048] The corrosion quantity of cable wire or anchor in the corrosion environment of the target bridge site is:

[0049]

[0050] In the formula, I bm and I bn are the corrosion currents of the cable metal protective coating and cable steel wire or anchor in the target bridge site corrosion environment, η bm and η bnare the sensitivity coefficients of cable metal protective coating and cable steel wire or anchor in the laboratory accelerated corrosion environment, t bm and t bn are the corrosion time of cable metal protective coating and cable steel wire or anchor in the target bridge site corrosion environment, T b RH b , and are the equivalent parameters of temperature, humidity, chloride ion concentration, and sulfate ion concentration, respectively;

[0051] S6: According to the principle of corrosion damage equivalence, establish the corrosion quantity Q of the metal coating protective layer of bridge cables under laboratory accelerated corrosion environment lsm Corrosion electricity of metal coating protective layer of bridge cables under target bridge site environment The equivalent relationship of Q and the corrosion quantity Q of bridge cable wire or anchor in the laboratory accelerated corrosion environment lsn Corrosion electricity of bridge cable wire or anchor in target bridge site environment The equivalent relationship between the laboratory accelerated corrosion environment and the target bridge site environment is obtained, that is, the conversion relationship between the corrosion time of the bridge cable metal coating protective layer and the bridge cable steel wire or anchor is obtained, that is, the equivalent conversion coefficient α m and α n , and perform corrosion equivalent conversion;

[0052] Among them, the corrosion quantity Q of the metal coating protective layer of the bridge cable in the laboratory accelerated corrosion environment lsm Corrosion electricity of bridge metal coating protective layer under target bridge site environment The equivalent relationship is:

[0053]

[0054] Right now

[0055] Corrosion quantity Q of bridge cable wire or anchor in laboratory accelerated corrosion environment lsn Corrosion electricity of bridge wire or anchor in target bridge site environment The equivalent relationship is:

[0056]

[0057] Right now

[0058] In the specific implementation of this scheme, for a large cable-bearing bridge in Qingdao, the cable metal coating protective layer is a zinc coating. According to the material properties of the metal material, the self-corrosion potential of the zinc coating is -0.41V, and the self-corrosion potential of the steel wire or anchor is -0.268V. Therefore, according to the calculation formula of the material sensitivity coefficient, the sensitivity coefficient η of the metal coating protective layer during the accelerated corrosion test is sm The material sensitivity coefficient η of the steel wire or anchor in the accelerated corrosion environment is 0.7790. sn is 1.3346; the material sensitivity coefficient η of the metal coating protective layer under the target bridge site environment bm =0.8220, the material sensitivity coefficient η of the steel wire or anchor under the target bridge site environment bn is 1.2575.

[0059] The influencing parameters of the laboratory accelerated corrosion environment, temperature T, humidity RH, chloride ion concentration and sulfate ion concentration Substituting into the function of bridge cable corrosion electricity obtained in step 3, the corrosion electricity Q of bridge cables under the laboratory accelerated corrosion environment is obtained. lsm , Q lsn ;

[0060] Corrosion electricity of the metal coating protective layer of bridge cables:

[0061]

[0062] Corrosion electricity of bridge cable wire or anchor:

[0063]

[0064] In this embodiment, for a large cable-supported bridge in Qingdao, the temperature T is 50°C, the humidity RH is 98%, and the chloride ion concentration is 5%, sulfate ion concentration The laboratory accelerated test was conducted for 180 days under a 3.5% environment.

[0065] Corrosion electricity of bridge cable protective layer:

[0066]

[0067] Corrosion electricity of bridge cable wire or anchor:

[0068]

[0069] Considering that the corrosion environment of the target bridge site changes with the seasons within a one-year period, the temperature T, humidity RH, and chloride ion concentration in the service environment of the bridge cable are and sulfate ion concentration There are large fluctuations, so the environmental parameters within the calculation period are equivalently converted and the weighted average method is used to obtain and By combining the fixed equivalent value of the environmental corrosion parameter obtained and the function of the corrosion electricity of the bridge cable system under the corrosion environment, the corrosion electricity of the bridge cable under the target bridge site corrosion environment can be obtained.

[0070] The corrosion quantity of the bridge cable protective layer under the corrosion environment of the target bridge site is:

[0071]

[0072] The corrosion quantity of the bridge cable wire or anchorage in the corrosion environment of the target bridge site:

[0073]

[0074] In this embodiment, for a large cable-bearing bridge in Qingdao, under the actual service environment of the bridge, the temperature T changes in the range of -12°C to 34°C, the humidity RH changes in the range of 30% to 95%, and the chloride ion concentration is The range of variation is 0.19%-0.98%, sulfate ion The concentration range is 0.07%-0.48%;

[0075] The constant equivalent parameters of each environmental parameter in the calculation period obtained by weighted average are: temperature humidity Chloride ion concentration and sulfate ion concentration Therefore:

[0076] The corrosion quantity of the bridge cable protective layer under the actual service environment:

[0077]

[0078] The corrosion quantity of the bridge cable wire or anchorage under the actual service environment:

[0079]

[0080] According to the corrosion damage equivalence principle, the corrosion charge Q of the metal coating protective layer of bridge cables under the laboratory accelerated corrosion environment is established. lsm Corrosion electricity of metal coating protective layer of bridge cables under target bridge site environment The equivalent relationship of and the corrosion quantity Q of bridge cable wire or anchor in the laboratory accelerated corrosion environment lsnCorrosion electricity of bridge cable wire or anchor in target bridge site environment The equivalent relationship is used to determine the conversion relationship of the corrosion time of the bridge cable metal coating protective layer and the bridge cable steel wire or anchor in the laboratory accelerated corrosion environment and the target bridge site environment, that is, the equivalent conversion coefficient α m and α n , to calculate the corrosion equivalent;

[0081] Corrosion quantity Q of metal coating protective layer of bridge cables in laboratory accelerated corrosion environment lsm Corrosion electricity of bridge metal coating protective layer under target bridge site environment The equivalent relationship is:

[0082]

[0083] Right now

[0084] Corrosion quantity Q of bridge cable wire or anchor in laboratory accelerated corrosion environment lsn Corrosion electricity of bridge wire or anchor in target bridge site environment The equivalent relationship is:

[0085]

[0086] Right now

[0087] In this embodiment, in the accelerated corrosion environment of the laboratory, it was found through observation that around the 45th day, the metal coating protective layer of the bridge cable began to rust, and the rust area was less than 5%. Around the 82nd day, the surface rust area of ​​the metal coating protective layer of the bridge cable was greater than 5% and less than 20%. Around the 108th day, the rust area of ​​the metal coating protective layer was greater than 20%, and the steel wire was exposed and rusted. Around the 136th day, large areas of rust appeared on the surface of the bridge cable steel wire or anchor. Around the 157th day, large areas of rust and rust pits appeared on the surface of the bridge cable steel wire or anchor. Around the 178th day, the bridge cable steel wire or anchor was close to a broken wire state.

[0088] The equivalent conversion factor for the accelerated corrosion test of the metal coating protective layer of bridge cables is:

[0089]

[0090]

[0091] When the protective layer of the bridge cable is completely corroded, the bridge cable wire or anchor begins to corrode. The equivalent conversion method for the accelerated corrosion test of the bridge cable wire or anchor is:

[0092]

[0093]

[0094] Therefore, when the metal coating protective layer of the bridge cable began to corrode on the 45th day, the corresponding corrosion time under the actual bridge site environment was 45×69.7019≈3137 days, about 8 years and 7 months; when on the 82nd day, the surface rust area of ​​the metal coating protective layer of the bridge cable was greater than 5% and less than 20%, the corresponding corrosion environment under the actual bridge site environment was 82×69.7019≈5716 days, about 15 years and 8 months; when on the 108th day, the rust area of ​​the metal coating protective layer of the bridge cable was greater than 20%, and the steel wire was exposed and rusted, the corresponding corrosion time under the actual bridge site environment was 108×69.7019≈7528 days, about 20 years and 7 months.

[0095] When large-scale rust appears on the surface of the bridge cable wire or anchor on the 136th day, the corresponding corrosion time under the actual bridge site environment is 7528+(136-108)×78.0560≈9714 days, about 26 years and 7 months; when large-scale rust and rust pits appear on the surface of the bridge cable wire or anchor on the 157th day, the corresponding corrosion time under the actual bridge site environment is 9714+(157-136)×78.0560≈11353 days, about 31 years and 1 month; when the bridge cable wire or anchor is close to broken wire on the 178th day, the corresponding corrosion time under the actual bridge site environment is 11353+(178-157)×78.0560≈12992 days, about 35 years and 7 months.

Claims

1. A method for calculating the equivalent accelerated corrosion of bridge cables, characterized in that: Including the inference of corrosion parameters such as temperature T, humidity RH, and chloride ion concentration based on the electrochemical conversion principle of metal material corrosion equivalent and sulfate ion concentration The influence function on the corrosion current is calculated and applied to the accelerated corrosion test environment and the target bridge site corrosion environment to calculate the corrosion quantity Q respectively. The equivalent conversion coefficient α is calculated based on the corrosion damage equivalence principle. The specific conversion method is: S1: According to the corrosion parameters temperature T, humidity RH, chloride ion concentration and sulfate ion concentration The influence of each parameter on the corrosion current I is proposed. Among them, the function of the influence of environmental corrosion parameters on corrosion current I is specifically: In the formula, η is the material sensitivity coefficient, T is the corrosion parameter temperature, RH is the humidity, is the chloride ion concentration, is the sulfate ion concentration; S2: Based on the function of corrosion current I, corrosion time t and Faraday's law obtained in S1, the corrosion quantity Q of the bridge cable system under the corrosive environment until it corrodes to a fixed level is obtained; Among them, the corrosion quantity Q of the bridge cable is: In the formula, Q is the corrosion charge, I is the corrosion current, t is the corrosion time, η is the material sensitivity coefficient, T is the corrosion parameter temperature, RH is the humidity, is the chloride ion concentration, is the sulfate ion concentration; S3: The bridge cables are divided into the cable metal protective coating corrosion stage and the cable steel wire or anchor corrosion stage according to the corrosion sequence. The corrosion current of the bridge cable protective layer is obtained according to the different specifications of bridge cables, different material properties and the thickness of the metal coating protective layer, which have different effects on the electrochemical corrosion of the bridge cables. lm And the corrosion quantity Q of cable wire or anchor ln ; The corrosion power of bridge cables includes the corrosion power of the metal protective coating of bridge cables Q lm and the corrosion charge Q of cable wire or anchor ln , the formula is: Q lm =I m t m (t≤t mmax ) Q ln =I n t n (t≥t mmax ) Where, t m is the time for the cable metal protective coating to be corroded; t n is the time for cable wire or anchor to be corroded; t mmax It is the time required for the cable metal protective coating to rust and fail. When the cable metal protective coating is completely corroded, t m＝ t mmax ; t is the total time of bridge cable corrosion, t = t m +t n ; S4: The influencing parameters of the laboratory accelerated corrosion environment, temperature T, humidity RH, chloride ion concentration and sulfate ion concentration Substituting into the function of bridge cable corrosion electricity obtained by S3, the corrosion electricity Q of the metal coating protective layer under the laboratory accelerated corrosion environment is obtained. lsm , and the corrosion charge Q of cable wire or anchor lsn ; Among them, the corrosion quantity Q of the cable metal protective coating under the laboratory accelerated corrosion environment is lsm for: Corrosion quantity Q of cable wire or anchor lsn for: In the formula, I sm and I sn are the corrosion currents of the cable metal protective coating and cable steel wire or anchor in the laboratory accelerated corrosion environment, η sm and η sn are the material sensitivity coefficients of the cable metal protective coating and cable steel wire or anchor in the laboratory accelerated corrosion environment, t sm and t sn are the corrosion time of cable metal protective coating and cable steel wire or anchor in the laboratory accelerated corrosion environment, T s RH s , and They are the temperature, humidity, chloride ion concentration, and sulfate ion concentration in the laboratory accelerated corrosion environment; S5: Based on the temperature T, humidity RH, chloride ion concentration λ in the target bridge site corrosion environment within the set time period cl- and sulfate ion concentration The fluctuations existing in the environment parameters within the set time period are equivalently converted, and the equivalent parameters of the environmental parameters are obtained. Combined with the function of the corrosion electricity of the bridge cable system under the corrosive environment in S2, the corrosion electricity of the metal coating protective layer under the corrosive environment of the target bridge site is obtained. and corrosion of cable wires or anchors Among them, the corrosion quantity of the cable metal protective coating in the target bridge site corrosion environment is: The corrosion quantity of cable wire or anchor in the corrosion environment of the target bridge site is: In the formula, I bm and I bn are the corrosion currents of the cable metal protective coating and cable steel wire or anchor in the target bridge site corrosion environment, η bm and η bn are the material sensitivity coefficients of the cable metal protective coating and cable steel wire or anchor in the laboratory accelerated corrosion environment, t bm and t bn are the corrosion time of cable metal protective coating and cable steel wire or anchor in the target bridge site corrosion environment, T b RH b , and are the equivalent parameters of temperature, humidity, chloride ion concentration, and sulfate ion concentration, respectively; S6: According to the principle of corrosion damage equivalence, establish the corrosion quantity Q of the metal coating protective layer of bridge cables under laboratory accelerated corrosion environment lsm Corrosion electricity of metal coating protective layer of bridge cables under target bridge site environment The equivalent relationship between the corrosion quantity Q of bridge cable wire or anchor in the laboratory accelerated corrosion environment lsn Corrosion electricity of bridge cable wire or anchor in target bridge site environment The equivalent relationship between the laboratory accelerated corrosion environment and the target bridge site environment is obtained, that is, the conversion relationship between the corrosion time of the bridge cable metal coating protective layer and the bridge cable steel wire or anchor is obtained, that is, the equivalent conversion coefficient α m and α n , and perform corrosion equivalent conversion; Among them, the corrosion quantity Q of the metal coating protective layer of the bridge cable in the laboratory accelerated corrosion environment lsm Corrosion electricity of bridge metal coating protective layer under target bridge site environment The equivalent relationship is: Right now Corrosion quantity Q of bridge cable wire or anchor in laboratory accelerated corrosion environment lsn Corrosion electricity of bridge wire or anchor in target bridge site environment The equivalent relationship is: Right now In the formula, α m is the equivalent conversion coefficient of the corrosion time of the metal coating protective layer of the bridge cable in the laboratory accelerated corrosion environment and the target bridge site environment, α n It is the equivalent conversion coefficient of the corrosion time of bridge cable wire or anchor in the laboratory accelerated corrosion environment and the target bridge site environment.

2. The equivalent conversion method for accelerated corrosion of bridge cables according to claim 1 is characterized in that: The fixed levels of corrosion of the bridge cable system in step S2 include: level I, level II, level III, level IV, level V and level VI; level I means that the cable metal protective coating has not rusted; level II means that the cable metal protective coating has rusted, and the rust area is less than 5%; level III means that the metal protective coating has a rust area greater than or equal to 5% and less than 20%; level IV means that the metal protective coating has a rust area greater than or equal to 20%, and the steel wire or anchor is exposed and rusted; level V means that the cable steel wire or anchor has corrosion pits, and level VI means that groove-shaped rust pits appear on the surface of the cable steel wire or anchor and the steel wire or anchor is broken.

3. The equivalent conversion method for accelerated corrosion of bridge cables according to claim 1 is characterized in that: The calculation method of the equivalent parameters of the corrosion environment parameters under the corrosion environment of the target bridge site in step S5 is: A year is divided into several periods. In each period, the corrosion environment parameters are tested several times and the average value is taken. The equivalent parameters of the corrosion environment parameters are calculated based on the average value. The formula is: In the formula, is the constant equivalent value of the corrosion environment parameter, that is, the constant equivalent value of the temperature T b , constant equivalent value of humidity RH b , constant equivalent value of chloride ion concentration and a constant equivalent value of sulfate ion concentration One of the following; x i is the average value of the corrosion environment parameter in the ith period; t i is the average value x i Number of occurrences; t 总 is the total number of time periods in the calculation cycle.

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