Fireproofing and corrosion protection of steel wire rope suspension cables of suspension bridges and method and system for monitoring the state thereof

Abstract

This invention discloses a method and system for fire prevention, corrosion protection, and condition monitoring of steel wire rope suspenders for suspension bridges. The method includes: dividing the bridge into fire-resistant and transition sections: the fire-resistant section is located above the bridge deck, and the transition section is located at the top of the fire-resistant section extending upwards. During the construction of the fire-resistant section, the oxide layer on the surface of the steel wire is first removed, followed by an epoxy primer, then a layered intumescent epoxy fire-retardant coating is applied using a fiber cloth interlayer reinforcement process, and finally a weather-resistant topcoat is applied. During the construction of the transition section, a sealed mold is used, and high-penetration resin is injected and pressurized for penetration filling. After pressure holding is completed, the inlet and outlet are sealed. After the resin cures, the mold is removed, and a weather-resistant topcoat consistent with that of the fire-resistant section is applied. Cathodic protection is implemented at the top extension of the transition section. During the construction of the fire-resistant section, distributed temperature and humidity sensors are pre-embedded, with leads extending to a monitoring terminal on the bridge deck to collect data in real time and provide early warnings through a preset model. This ensures the durability of the suspenders and the safe operation of the bridge.

Description

Technical Field

[0001] This invention belongs to the field of fire prevention and corrosion protection technology for steel wire rope slings of suspension bridges, and more specifically, relates to a method and system for fire prevention, corrosion protection, and condition monitoring of steel wire rope slings of suspension bridges. Background Technology

[0002] As the core component bearing the load of the bridge deck, the steel wire rope suspenders of suspension bridges directly determine the bridge's operational lifespan. Existing suspenders generally employ an open structure. The core advantage of this design lies in utilizing structural gaps to allow for rapid rainwater drainage, preventing moisture accumulation in the gaps between the steel wires and the formation of an electrochemical corrosion environment, thus ensuring the suspenders' corrosion resistance in typical outdoor environments.

[0003] However, bridge fire protection codes impose special requirements on cable protection, specifying that cables at a certain height above the bridge deck must be fire-resistant, typically requiring a closed-type fire-retardant coating. While this closed design meets fire performance standards, it conflicts with the drainage logic of open structures: it disrupts the original drainage path of the cables, preventing rainwater seeping into non-fire-resistant sections (open areas) from draining properly. Instead, rainwater seeps into the fire-resistant sections (closed areas) along the gaps in the steel wires. The sealed nature of the enclosed space makes it difficult for the seeping rainwater to evaporate, gradually creating a high-humidity corrosive environment inside, significantly accelerating steel wire corrosion, resulting in the contradictory situation of "meeting fire protection standards but exacerbating corrosion."

[0004] Currently, the industry lacks an effective solution to the contradiction between fireproof sealing and drainage / corrosion prevention: simply increasing the thickness of the fireproof coating to enhance fire resistance would further reduce drainage space and exacerbate drainage problems; using conventional anti-corrosion coatings to improve corrosion resistance would fail to meet the fire resistance requirements of areas above the bridge deck. This conflict in protection needs makes it difficult for existing technologies to simultaneously address the fire and corrosion resistance of the slings, leading to potential protection failures under long-term operation and threatening the structural safety of the slings. Therefore, there is an urgent need to construct an integrated protection system that can meet local fire protection requirements while blocking rainwater infiltration, thus overcoming the core technological bottleneck of current sling protection. Summary of the Invention

[0005] This invention aims to resolve the core contradiction between fireproof sealing and drainage / corrosion prevention in suspension bridge wire rope cables. Addressing the issue that while existing open cable structures facilitate drainage, they are prone to fire, and closed fireproof coatings, while meeting standards, obstruct drainage and lead to internal high-humidity corrosion, this invention establishes fireproof and transition sections, employing differentiated protection processes. This not only meets fire protection requirements for areas above the bridge deck but also blocks rainwater infiltration into the closed fireproof sections. Furthermore, cathodic protection and distributed temperature and humidity monitoring are used to construct an integrated system for fire prevention, corrosion prevention, and condition monitoring, ensuring cable durability and safe bridge operation.

[0006] To address the aforementioned deficiencies or improvement needs of existing technologies, as a first aspect of this invention, the present invention provides a method for fire prevention, corrosion protection, and condition monitoring of steel wire rope slings for suspension bridges, comprising: S1. Complete the zoning of fire protection sections and transition sections; fire protection sections are set in the area above the bridge deck; transition sections are set in the area extending upward from the top of the fire protection sections; S2. During the construction of the fireproof section, first remove the oxide layer on the surface of the steel wire, and then apply an epoxy primer on it to provide an anchoring interface for subsequent coatings; on the primer surface, apply an intumescent epoxy fireproof coating in layers using a fiber cloth interlayer reinforcement process; and apply 1-3 coats of weather-resistant topcoat to the fireproof coating surface. S3. During the construction of the transition section, a sealing mold is wrapped around the outside of the transition section. A high-penetration resin is injected into the mold and allowed to penetrate and fill the gaps between the steel wires under pressure. After grouting is stopped and pressure is maintained, the inlet and outlet are sealed. After the resin has cured, the mold is removed and the surface is coated with a weather-resistant topcoat that is the same as that of the fireproof section. S4. Implement cathodic protection reinforcement in the range from 0m to no less than 1m above the top of the transition section; at the same time, during the construction of the fireproof section, pre-embed distributed temperature and humidity sensors along the gaps in the steel wires, and extend the sensor leads along the inside of the suspension cable to the bridge deck monitoring terminal to collect internal temperature and humidity data in real time, and complete the early warning signal feedback through the preset model.

[0007] Furthermore, the dry film thickness of the epoxy primer in S2 is controlled within... .

[0008] Furthermore, in S2, the epoxy primer achieves underlying corrosion protection through the sacrificial anode effect of zinc powder or the pore sealing effect.

[0009] Furthermore, the fiber cloth interlayer reinforcement process in S2 is specifically as follows: after each 2-3mm thick coating is applied, a layer of fiber reinforcement material is laid, and the fiber weaving form is selected as plain weave, satin weave, or mesh structure according to the convenience of construction.

[0010] Furthermore, in S3, the sealing mold and the surface of the sling are radially sealed by a rubber sealing ring, and the mold is axially provided with one main grouting inlet and two to three venting outlets.

[0011] Furthermore, the specific method for strengthening cathodic protection in S4 is as follows: Install a sealed injection container at both ends outside the area, with a flow channel at the bottom of the container that fits into the surface of the sling; inject cathodic protection coating with a zinc powder content >90% into the container, and apply an auxiliary pressure of 0.1-0.3MPa to promote coating penetration; after standing for 2-4 hours to allow the coating to fully penetrate into the gaps between the steel wires, remove the container and clean the surface residue to form a sacrificial anode protection layer.

[0012] Furthermore, the preset model in S4 is specifically as follows: Assume the sensor acquisition period is Sampling interval The time-series dataset collected by the temperature and humidity sensor is ;in, The total number of time series data. They represent the first Humidity and temperature at each data collection point; extraction of time-series dataset. The core features are as follows: Humidity fluctuation range : , in, For time series datasets Humidity time-series dataset; Humidity is corrected by temperature: , in, This is the humidity value after temperature correction; This is the temperature influence coefficient, a constant calibrated through experimental / engineering experience; Reference temperature; Calculate the duration of high humidity : , in, For indicator functions; The high humidity risk threshold is a critical humidity value calibrated through experiments. Construct a risk index R, using dynamic weighted feature fusion: , in, This is the humidity fluctuation weighting coefficient; This is the critical value for humidity fluctuation; This is the cumulative weighting coefficient for high humidity. This refers to the critical duration of high humidity. Extreme humidity weighting coefficient; This is the corrected maximum humidity value; Risk baseline humidity; The span of the high humidity zone.

[0013] Furthermore, the warning signal feedback in S4 specifically includes: according to The value is matched to a preset threshold range to provide early warning signal feedback; the early warning signals include: green no warning signal, yellow level 3 warning signal, orange level 2 warning signal, and red level 1 warning signal; When a green warning signal is output, the structure is in a low-risk state, and the terminal displays "stable environment, low corrosion risk". No additional intervention is required, and the regular monitoring frequency should be maintained continuously. When a yellow Level 3 warning signal is issued, the risk probability is in the range of 30%-60%. In addition to displaying the warning level, the terminal will simultaneously push characteristic data. When an orange level 2 warning signal is output, the risk probability reaches 60%-80%. An automatic pop-up window will be displayed and a text message will be sent to the operation and maintenance terminal. High-risk items will be highlighted in the characteristic data, and a comprehensive test will be required within 48 hours, including the integrity of the fireproof section coating and the cathodic protection potential test. When a red Level 1 warning signal is issued, indicating a risk probability of ≥80%, an audible and visual alarm will be activated, the location information of high-risk monitoring points will be locked, emergency response suggestions will be pushed out, and emergency repair resources will be coordinated to ensure intervention and handling within 24 hours.

[0014] As a second aspect of the present invention, the present invention provides a fireproof, corrosion-resistant, and condition monitoring system for steel wire rope suspenders of suspension bridges, comprising: The zoning unit is used to set up fire protection sections and transition sections; the fire protection sections are set up in the area above the bridge deck; the transition sections are set up in the area extending upwards from the top of the fire protection sections. The fireproof section coating construction unit is used in the construction of fireproof sections. First, the oxide layer on the surface of the steel wire is removed, and then an epoxy primer that provides an anchoring interface for subsequent coatings is applied on it. On the primer surface, an intumescent epoxy fireproof coating is applied in layers using a fiber cloth interlayer reinforcement process. Finally, 1-3 coats of weather-resistant topcoat are applied to the fireproof coating surface. The transition section resin sealing unit is used in the construction of the transition section. It wraps the outer part of the transition section with a sealing mold, selects a high-penetration resin, injects it into the mold, and allows it to penetrate and fill the gaps in the steel wires under pressure. After the grouting is stopped and the pressure is maintained, the inlet and outlet are sealed. After the resin cures, the mold is removed and the surface is coated with a weather-resistant topcoat that is the same as that of the fireproof section. The reinforcement and monitoring deployment unit is used to implement cathodic protection reinforcement in the range from 0m to no less than 1m above the top of the transition section; at the same time, during the construction phase of the fireproof section, distributed temperature and humidity sensors are pre-embedded along the gaps in the steel wires, and the sensor leads extend along the inside of the suspension cable to the bridge deck monitoring terminal to collect internal temperature and humidity data in real time, and complete the early warning signal feedback through the preset model.

[0015] As a third aspect of the invention, the invention provides a computer-readable storage medium having a computer program stored thereon, the computer program being executed by a processor of any step of the fireproofing, corrosion protection, and condition monitoring method for the steel wire rope slings of the suspension bridge.

[0016] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: 1. The present invention provides a method for fire protection, corrosion prevention, and condition monitoring of suspension bridge wire rope suspenders. This method involves dividing the suspenders into fire-resistant sections and transition sections. The fire-resistant sections are located above the bridge deck, while the transition sections extend upwards from the top of the fire-resistant sections, clearly defining the protective functions of different areas of the suspenders. During the construction of the fire-resistant sections, the oxide layer on the steel wire surface is first removed, followed by an epoxy primer to provide an anchoring interface. Then, an intumescent epoxy-based fire-retardant coating is applied in layers using a fiber cloth interlayer reinforcement process, and finally, a weather-resistant topcoat is applied. This technical feature creates a multi-layered protective structure of "rust removal - primer - fire-retardant coating - topcoat" in the fire-resistant sections, effectively improving the fire resistance of the suspenders. Simultaneously, the epoxy primer ensures the adhesion of subsequent coatings, the fiber cloth interlayer reinforcement process prevents cracking of the fire-retardant coating, and the weather-resistant topcoat resists outdoor environmental erosion, achieving a long-term stable fire and corrosion protection effect for the fire-resistant sections.

[0017] 2. The method for fireproofing, corrosion protection, and condition monitoring of suspension bridge wire rope suspenders of the present invention involves wrapping a sealing mold during the construction of the transition section, injecting high-penetration resin, and applying pressure to allow it to penetrate and fill the gaps between the steel wires. After maintaining the pressure for at least 30 minutes, the inlet and outlet are sealed. After the resin cures, the mold is removed, and a weather-resistant topcoat consistent with that of the fireproof section is applied. This technical feature utilizes the permeability and pressure of the high-penetration resin to fully fill the gaps between the steel wires in the transition section, forming a dense sealing layer that blocks the penetration paths of corrosive media such as rainwater and moisture. The pressure-holding operation ensures that the resin is fully filled without gaps, and the subsequent application of the weather-resistant topcoat ensures that the appearance and protective performance of the transition section are uniform with those of the fireproof section, significantly improving the sealing and corrosion protection capabilities of the transition section and avoiding corrosion problems caused by seal failure.

[0018] 3. The fireproofing, corrosion protection, and condition monitoring method for suspension bridge wire rope suspenders of the present invention involves implementing cathodic protection reinforcement from 0m to at least 1m above the top of the transition section, while simultaneously pre-embedding distributed temperature and humidity sensors during the construction phase of the fireproof section. The sensor leads are extended to the bridge deck monitoring terminal, and early warning signals are fed back through a preset model. In this technical feature, cathodic protection reinforcement provides additional corrosion protection to the top area of ​​the transition section, slowing down the corrosion rate of the wire rope in this area; the distributed temperature and humidity sensors can collect real-time temperature and humidity data inside the suspenders, and the bridge deck monitoring terminal, combined with the preset model, promptly feeds back early warning signals, enabling personnel to monitor the internal environmental conditions of the suspenders in real time, detect potential fire and corrosion risks in advance, achieve dynamic monitoring and risk warning of the suspender condition, and ensure the long-term safe operation of the suspenders. Attached Figure Description

[0019] Figure 1 This is a flowchart of a method for fire prevention, corrosion protection, and condition monitoring of steel wire rope slings for suspension bridges according to an embodiment of the present invention. Figure 2 This is a cross-sectional view of the construction process of bridges with medium and low fire resistance ratings according to an embodiment of the present invention; Figure 3This is a schematic diagram of the construction process for bridges with medium and low fire resistance ratings according to an embodiment of the present invention; Figure 4 This is a cross-sectional view of the construction process of a high fire-resistant bridge according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the construction process for high fire-resistant bridges according to an embodiment of the present invention; Figure 6 This is a system unit diagram of an embodiment of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0021] Example 1 Please refer to Figure 1 This embodiment 1 provides a method for fire prevention, corrosion protection, and condition monitoring of steel wire rope slings for suspension bridges, including: S1. Complete the zoning of fire protection sections and transition sections; fire protection sections are set in the area above the bridge deck; transition sections are set in the area extending upward from the top of the fire protection sections; S2. During the construction of the fireproof section, first remove the oxide layer on the surface of the steel wire, and then apply an epoxy primer on it to provide an anchoring interface for subsequent coatings; on the primer surface, apply an intumescent epoxy fireproof coating in layers using a fiber cloth interlayer reinforcement process; and apply 1-3 coats of weather-resistant topcoat to the fireproof coating surface. S3. During the construction of the transition section, a sealing mold is wrapped around the outside of the transition section. A high-penetration resin is injected into the mold and allowed to penetrate and fill the gaps between the steel wires under pressure. After grouting is stopped and pressure is maintained, the inlet and outlet are sealed. After the resin has cured, the mold is removed and the surface is coated with a weather-resistant topcoat that is the same as that of the fireproof section. S4. Implement cathodic protection reinforcement in the range from 0m to no less than 1m above the top of the transition section; at the same time, during the construction of the fireproof section, pre-embed distributed temperature and humidity sensors along the gaps in the steel wires, and extend the sensor leads along the inside of the suspension cable to the bridge deck monitoring terminal to collect internal temperature and humidity data in real time, and complete the early warning signal feedback through the preset model.

[0022] This embodiment 1 further elaborates on the above process.

[0023] (1) Partition settings To resolve the contradiction between fireproof sealing and drainage / corrosion prevention in existing suspension cables, this embodiment 1 first proposes a zoned approach, dividing the area into fireproof sections and transition sections, clearly defining the functional roles of different areas to achieve synergistic protection. Considering the practical needs of bridge operation—the area above the bridge deck must meet fire safety standards, while the non-fireproof sections require drainage and corrosion prevention—the fireproof sections are located above the bridge deck to specifically address the potential high temperatures and fire risks in this area. The transition sections are located at the top of the fireproof sections, extending upwards to connect the fireproof and non-fireproof sections, thus resolving the issue of the fireproof coating disrupting the original drainage path.

[0024] Based on this, the present invention adopts a segmented design of "fireproof section + transition section," combined with innovative material selection and construction techniques to form an integrated protection system. In terms of structural zoning design, the fireproof section is specifically located in the 0-25m height range above the bridge deck. This range is determined according to the actual fire resistance rating of the bridge, ensuring precise coverage of areas requiring key fire protection and undertaking the core fire protection function. The transition section extends 0-1m upwards from the top of the fireproof section, serving as a functional transition zone between the fireproof and non-fireproof sections, primarily responsible for waterproofing and sealing. Through this zoning design, the fireproof section focuses on meeting the fire protection requirements of the area above the bridge deck, while the transition section prevents rainwater from the non-fireproof section from seeping into the fireproof section, avoiding the formation of a high-humidity corrosive environment in the enclosed space. This achieves an organic unity of fire protection and corrosion prevention functions, resolving the core contradiction of traditional cable-stayed bridge protection.

[0025] (2) Fireproof section coating construction During the construction of the fireproof section, the substrate pretreatment is carried out first: In a preferred embodiment, Sa2.5 grade sandblasting is used to remove the oxide layer on the surface of the steel wire, followed by the application of an epoxy primer. In a preferred embodiment, the primer can be either zinc-rich epoxy or closed-type epoxy, with the dry film thickness controlled at 40-120μm. The zinc-rich epoxy primer achieves undercoat corrosion protection through the sacrificial anode effect of zinc powder, while the closed-type primer achieves corrosion protection through pore sealing. Both types of epoxy primers provide a stable anchoring interface for subsequent coatings, ensuring adhesion between coatings.

[0026] After the substrate pretreatment is completed, the fire-resistant reinforcement layer is applied: an intumescent epoxy fire-resistant coating is applied in layers to the primer surface. The coating can be a solvent-free epoxy fire-resistant coating or an aerogel-modified epoxy fire-resistant coating, with a total thickness of 3-10 mm selected based on the required fire resistance rating of the sling. In a preferred embodiment, to address the issue of cracking in thick coatings, a fiber cloth interlayer reinforcement process is used during construction. Specifically, after each 2-3 mm thick layer of fire-resistant coating is applied, a layer of fiber reinforcement material is laid. The fiber reinforcement material can be carbon fiber cloth or basalt fiber cloth, and its weaving pattern can be plain weave, satin weave, or mesh structure, depending on the ease of construction.

[0027] Finally, apply the weather-resistant topcoat: apply 1-3 coats of weather-resistant topcoat to the fireproof coating surface. The topcoat can be made of fluorocarbon resin, polysiloxane, or polyurethane coating to form a protective barrier that resists ultraviolet rays and acid rain, further improving the overall weather resistance and service life of the fireproof section.

[0028] (3) Transition section resin sealing The transition section construction uses pressure grouting technology as its core. Through mold sealing, resin injection and subsequent treatment, a sealed barrier is built to prevent rainwater penetration. At the same time, cathodic protection is combined to enhance the anti-corrosion capability.

[0029] During the mold installation phase, a custom-made sealing mold is wrapped around the transition section. The material can be stainless steel or high-strength composite material. The mold and the sling surface are radially sealed by a rubber sealing ring to prevent resin leakage during grouting. The mold is axially equipped with one main grouting inlet and two to three vents. The main inlet is used for resin injection, while the vents ensure that air is smoothly discharged during grouting, avoiding the formation of air bubbles that affect the sealing effect.

[0030] For the resin injection process, high-permeability resins, such as modified epoxy resin, polyurethane elastomer, or silicone resin, are selected and injected into the mold under pressure of 0.5-2 MPa using a plunger pump or screw pump. Under pressure, the resin fully permeates along the gaps in the steel wires, filling the tiny crevices. When continuous resin overflows from all vents without air bubbles, the injection is considered complete. After stopping the injection, pressure is maintained for 30 minutes to ensure the resin fully wets the gaps, and then the inlets and outlets are sealed to prevent backflow.

[0031] In subsequent processing, after the resin has cured for 24-48 hours, the mold is removed, and a weather-resistant topcoat consistent with that of the fireproof section is applied to the surface of the transition section to achieve uniformity in appearance and weather resistance.

[0032] (4) Strengthen and monitor deployment After completing the main protective construction of the fireproof section and transition section, in order to achieve dynamic control over the condition of the slings and further enhance the corrosion resistance of key areas, this invention simultaneously implements internal condition monitoring and top corrosion protection measures, forming a closed-loop protection system of "protection + monitoring".

[0033] The design of internal condition monitoring was carried out simultaneously with the construction of the fireproof section. During the construction phase of the fireproof section, distributed temperature and humidity sensors were pre-embedded along the gaps in the steel wires, with monitoring points set at intervals of 5-8 meters. The sensor leads extended along the inside of the suspension cable to the monitoring terminal on the bridge deck. This approach allows for real-time collection of temperature and humidity data inside the suspension cable, providing first-hand information for corrosion risk assessment.

[0034] The data is processed through a pre-set model: based on the collected temperature and humidity time-series data, features such as humidity fluctuation amplitude, corrected humidity, and duration of high humidity are extracted, and a risk index is calculated by fusing these features. Then, based on the index and matching threshold ranges, signals such as green (no warning) and yellow, orange, and red (tiered warnings) are output. This allows staff to promptly grasp changes in the internal environment of the slings, detect potential corrosion risks in advance, avoid the passivity of traditional reactive maintenance methods, and provide dynamic protection for the safe operation of the slings.

[0035] In a preferred embodiment, the preset model is specifically as follows: Assume the sensor acquisition period is Sampling interval The time-series dataset collected by the temperature and humidity sensor is ;in, The total number of time series data. They represent the first Humidity and temperature at each data collection point; extraction of time-series dataset. The core features are as follows: Humidity fluctuation range : , in, For time series datasets Humidity time-series dataset; Humidity is corrected by temperature: , in, This is the humidity value after temperature correction; This is the temperature influence coefficient, a constant calibrated through experimental / engineering experience; Reference temperature; Calculate the duration of high humidity : , in, For indicator functions; The high humidity risk threshold is a critical humidity value calibrated through experiments. Construct a risk index R, using dynamic weighted feature fusion: , in, This is the humidity fluctuation weighting coefficient; This is the critical value for humidity fluctuation; This is the cumulative weighting coefficient for high humidity. This refers to the critical duration of high humidity. Extreme humidity weighting coefficient; This is the corrected maximum humidity value; Risk baseline humidity; The span of the high humidity zone.

[0036] In a preferred embodiment, the warning signal feedback specifically includes: according to The value is matched to a preset threshold range to provide early warning signal feedback; the early warning signals include: green no warning signal, yellow level 3 warning signal, orange level 2 warning signal, and red level 1 warning signal; When a green warning signal is output, the structure is in a low-risk state, and the terminal displays "stable environment, low corrosion risk". No additional intervention is required, and the regular monitoring frequency should be maintained continuously. When a yellow Level 3 warning signal is issued, the risk probability is in the range of 30%-60%. In addition to displaying the warning level, the terminal will simultaneously push characteristic data. When an orange level 2 warning signal is output, the risk probability reaches 60%-80%. An automatic pop-up window will be displayed and a text message will be sent to the operation and maintenance terminal. High-risk items will be highlighted in the characteristic data, and a comprehensive test will be required within 48 hours, including the integrity of the fireproof section coating and the cathodic protection potential test. When a red Level 1 warning signal is issued, indicating a risk probability of ≥80%, an audible and visual alarm will be activated, the location information of high-risk monitoring points will be locked, emergency response suggestions will be pushed out, and emergency repair resources will be coordinated to ensure intervention and handling within 24 hours.

[0037] The top anti-corrosion reinforcement measures are implemented in the non-fireproof area 0-1m above the top of the transition section, effectively supplementing the waterproof sealing process of the transition section. A sealed injection container is installed outside this area, with a flow channel at the bottom of the container that fits against the surface of the sling. Cathodic protection coating with a zinc powder content >90% is injected into the container, and an auxiliary pressure of 0.1-0.3MPa is applied to promote coating penetration. After standing for 2-4 hours to allow the coating to fully penetrate the gaps in the steel wires, the container is removed and any remaining material is cleaned from the surface, forming a sacrificial anode protective layer.

[0038] This measure delays steel wire corrosion through the sacrificial anode effect, synergizes with the waterproof sealing of the transition section, further blocks the corrosion path, improves the corrosion resistance and durability of the upper area of ​​the sling, and ensures the integrity and reliability of the overall sling protection system.

[0039] Please refer to Figure 2 as well as Figure 3 For the cable protection requirements of bridges with medium to low fire resistance ratings, the preferred embodiment follows the logic of "zoning and positioning - segmented construction - enhanced monitoring," and the specific process is as follows: First, the zones are set up. Based on the fire protection level requirements of the bridge, the fire protection zone is defined as the area 0-10m above the bridge deck. This area is directly exposed to the potential fire risk of the bridge deck and its fire protection performance needs to be strengthened. The transition zone is set as the area 0-0.6m above the top of the fire protection zone. It serves as the connection zone between the fire protection zone and the non-fire protection zone and undertakes the function of waterproof sealing to prevent rainwater from seeping into the fire protection zone.

[0040] The fireproof section construction then commenced: the first step was substrate treatment, using sandblasting to remove the oxide layer and impurities from the steel wire surface, creating a clean, rough adhesion surface. Afterward, an epoxy zinc-rich primer was applied, controlling the dry film thickness to [specific thickness missing]. The first step involves using zinc powder as a sacrificial anode to achieve initial corrosion protection, while also providing a stable anchoring interface for subsequent coatings. The second step involves constructing a fireproof layer using solvent-free epoxy fireproof coating, with a total thickness of 4mm. To prevent cracking of the thick coating, a layered application method combined with fiber cloth reinforcement is employed. After each 2mm thick coat, a layer of high-density fiber cloth is laid. The basalt fiber plain weave fabric enhances the integrity and crack resistance of the fireproof layer by utilizing the stress dispersion effect of the fiber fabric, ensuring the formation of a complete fire barrier under high temperatures; the third step is to apply the topcoat, coating two coats of fluorocarbon paint to control the total dry film thickness. By utilizing the excellent UV resistance and acid rain resistance of fluorocarbon resin, the underlying fireproof coating is protected from natural environmental erosion, extending the overall protection life of the fireproof section.

[0041] Next, the transition section sealing operation was carried out: First, a custom-made stainless steel sealing mold was installed, with a length of 0.6m. One axial injection port was provided for resin injection, and two vent ports ensured air was expelled during injection to prevent air bubbles from affecting the sealing effect; a 5000m viscosity resin was selected. Modified epoxy resin was used as the sealing material, and pumped at 1.0... The resin is injected into the mold under pressure. Under pressure, the resin fully penetrates along the gaps in the steel wires. The injection is stopped when resin continuously overflows from all vents without any bubbles. The pressure is maintained for 20 minutes to ensure that the resin is fully filled. Then the inlet and outlet are sealed. After the resin has completely cured, the mold is removed. A coat of polysiloxane topcoat is applied to the surface of the transition section to make the appearance and weather resistance of the transition section consistent with the fireproof section, while further enhancing the waterproof effect of the transition section.

[0042] Finally, monitoring deployment and top reinforcement work were carried out simultaneously: For monitoring, one temperature and humidity sensor was pre-embedded at 5m and 10m in the fireproof section. The sensor lead wires extended along the inside of the cable to the bridge deck monitoring terminal, which can collect internal temperature and humidity data at different heights in the fireproof section in real time, providing accurate data support for subsequent corrosion risk early warning; For top reinforcement, the non-fireproof area 0-0.6m above the transition section was covered with a stainless steel container. The container was attached to the surface of the cable to ensure the coating was retained. Cathodic protection coating with a zinc powder content of 92% was injected into the container and left to stand for 3 hours to allow the coating to naturally seep into the gaps between the steel wires. After that, the container was removed and the surface residue was cleaned to form a sacrificial anode protection layer. The sacrificial anode effect delayed the corrosion of the steel wires in this area, forming a synergistic protection with the sealing of the transition section and improving the corrosion resistance reliability of the upper area of ​​the cable.

[0043] Please refer to Figure 4 as well as Figure 5 In a preferred embodiment, a bridge with high fire resistance requirements is provided, and a specific construction method is provided as follows: First, the zones are set up. Based on the safety standards for high fire-resistant bridges, the fire protection zone is defined as the area 0-20m above the bridge deck. This range covers the core area that may be affected by a fire on the bridge deck and can fully resist high-temperature radiation and flame attack. The transition zone is set as the area 0-1m above the top of the fire protection zone. By extending the length of the transition zone, the connection buffer zone between the fire protection zone and the non-fire protection zone is further widened, improving the reliability of waterproof sealing and preventing rainwater from seeping into the deeper fire protection zone along the gaps in the steel wires.

[0044] The fireproof section construction then commenced: the first step was substrate treatment, employing sandblasting to thoroughly remove the oxide layer, rust, and oil from the steel wire surface, creating a clean, rough surface. Following this, an epoxy sealing primer was applied, controlling the dry film thickness to [specific thickness missing]. Compared to epoxy zinc-rich primers used for medium and low fire resistance ratings, epoxy sealing primers, through their dense film structure, more tightly fill the pores on the steel wire surface, effectively blocking the intrusion of corrosive media such as moisture and salt, providing a more stable adhesion base for subsequent coatings. The second step involves constructing the fireproof layer using aerogel-modified epoxy fireproof coating. This coating possesses superior high-temperature insulation properties, with a total coating thickness of 8mm to meet high fire resistance requirements. During construction, a combination of layered application and fiber cloth reinforcement is used. After each 3mm thick layer of coating, a layer of 5mm×5mm pore size carbon fiber mesh is laid. The high strength of the carbon fiber mesh effectively disperses the coating's shrinkage stress, preventing cracks in the thick coating due to temperature changes or cable vibration, ensuring uniform expansion and foaming of the fireproof coating under high-temperature conditions, forming a complete and robust fire barrier. The third step involves applying the topcoat, coating three coats of polyurethane topcoat, controlling the total dry film thickness. Polyurethane topcoat has better weather resistance and anti-aging properties, and can resist the erosion of harsh environments such as strong ultraviolet rays and acid rain for a long time, avoiding premature aging and failure of the underlying fireproof coating and extending the overall protection period of the fireproof section.

[0045] Next, the transition section sealing operation was carried out: First, a customized high-strength composite material sealing mold was installed. The mold was 1m long. Compared with stainless steel molds, high-strength composite materials have the advantages of being lightweight and corrosion-resistant, making them more suitable for long-term outdoor use. The mold was axially equipped with one injection port and three vent ports. Increasing the number of vent ports allows for more comprehensive removal of air during the grouting process, reducing air bubble residue and improving the sealing tightness. A viscosity was selected... Polyurethane elastomer was used as the sealing material. This material has good flexibility and adhesion, and can better adapt to the small deformations caused by the vibration of the sling. It was then pumped using a screw pump... The resin is injected into the mold under pressure, and it fully penetrates the gaps between the steel wires under pressure. The injection is stopped when resin continuously overflows from all vents without bubbles. The pressure is maintained for 40 minutes to ensure that the resin fully wets the gaps between the steel wires and initially cures. Then the inlet and outlet are sealed. After the resin has fully cured, the mold is removed, and two coats of fluorocarbon topcoat are applied to the surface of the transition section. The stain resistance and weather resistance of the fluorocarbon topcoat can further enhance the protective effect of the transition section, while keeping the appearance and performance of the transition section and the fireproof section consistent, avoiding weak points in protection due to material differences.

[0046] Finally, monitoring deployment and top reinforcement work were carried out simultaneously: For monitoring, one temperature and humidity sensor was pre-embedded at 5m, 10m, 15m, and 20m along the fire-resistant section. By increasing the number of monitoring nodes, internal temperature and humidity changes at different heights of the fire-resistant section can be captured more accurately, avoiding the omission of localized high-humidity risks due to monitoring blind spots. The sensor leads extend along the inside of the suspension cables to the bridge deck monitoring terminal, providing more comprehensive real-time data for subsequent risk index calculation and early warning. For top reinforcement, the non-fire-resistant area 0-1m above the transition section was covered with plastic containers. These lightweight and easy-to-install containers better fit the suspension cables. On the surface, a cathodic protection coating with a zinc powder content of 95% is injected into the container. Compared with the 92% zinc powder content coating used for medium and low fire ratings, the higher zinc powder content can enhance the sacrificial anode effect. At the same time, an auxiliary pressure of 0.2MPa is applied to promote the rapid and sufficient penetration of the coating into the gaps between the steel wires. After standing for 4 hours, the coating is allowed to adhere tightly to the surface of the steel wires. Then, the container is removed and the surface residue is cleaned to form a dense sacrificial anode protective layer. This protective layer, together with the waterproof sealing of the transition section, forms a synergistic protection, further improving the corrosion resistance of the upper area of ​​the suspender and meeting the stringent requirements of high fire rating bridges for the long-term durability of the suspenders.

[0047] Example 2 Please refer to Figure 6 This embodiment 2 provides a fireproof, corrosion-resistant, and condition monitoring system for steel wire rope slings of suspension bridges, including: The zoning unit is used to set up fire protection sections and transition sections; the fire protection sections are set up in the area above the bridge deck; the transition sections are set up in the area extending upwards from the top of the fire protection sections. The fireproof section coating construction unit is used in the construction of fireproof sections. First, the oxide layer on the surface of the steel wire is removed, and then an epoxy primer that provides an anchoring interface for subsequent coatings is applied on it. On the primer surface, an intumescent epoxy fireproof coating is applied in layers using a fiber cloth interlayer reinforcement process. Finally, 1-3 coats of weather-resistant topcoat are applied to the fireproof coating surface. The transition section resin sealing unit is used in the construction of the transition section. It wraps the outer part of the transition section with a sealing mold, selects a high-penetration resin, injects it into the mold, and allows it to penetrate and fill the gaps in the steel wires under pressure. After the grouting is stopped and the pressure is maintained, the inlet and outlet are sealed. After the resin cures, the mold is removed and the surface is coated with a weather-resistant topcoat that is the same as that of the fireproof section. The reinforcement and monitoring deployment unit is used to implement cathodic protection reinforcement in the range from 0m to no less than 1m above the top of the transition section; at the same time, during the construction phase of the fireproof section, distributed temperature and humidity sensors are pre-embedded along the gaps in the steel wires, and the sensor leads extend along the inside of the suspension cable to the bridge deck monitoring terminal to collect internal temperature and humidity data in real time, and complete the early warning signal feedback through the preset model.

[0048] Example 3 This embodiment 3 also provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it can implement any step of a method for fire prevention, corrosion protection, and condition monitoring of steel wire rope slings for suspension bridges.

[0049] The computer-readable storage medium may include various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0050] For a description of the computer-readable storage medium provided in this application, please refer to the above method embodiments; further details will not be repeated here.

[0051] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for fire prevention, corrosion protection, and condition monitoring of steel wire rope suspenders for suspension bridges, characterized in that, include: S1. Complete the zoning of fire protection sections and transition sections; fire protection sections are set in the area above the bridge deck; transition sections are set in the area extending upward from the top of the fire protection sections; S2. During the construction of the fireproof section, first remove the oxide layer on the surface of the steel wire, and then apply an epoxy primer on it to provide an anchoring interface for subsequent coatings; apply an intumescent epoxy fireproof coating in layers on the primer surface using a fiber cloth interlayer reinforcement process; and apply 1-3 coats of weather-resistant topcoat on the fireproof coating surface. S3. During the construction of the transition section, a sealing mold is wrapped around the outside of the transition section. A high-penetration resin is injected into the mold and allowed to penetrate and fill the gaps between the steel wires under pressure. After grouting is stopped and pressure is maintained, the inlet and outlet are sealed. After the resin has cured, the mold is removed and the surface is coated with a weather-resistant topcoat that is the same as that of the fireproof section. S4. Cathodic protection reinforcement shall be implemented in the range from 0m to no less than 1m above the top of the transition section; at the same time, during the construction of the fireproof section, distributed temperature and humidity sensors shall be pre-embedded along the gaps in the steel wires, and the sensor leads shall extend along the inside of the suspension cable to the bridge deck monitoring terminal to collect internal temperature and humidity data in real time, and complete the early warning signal feedback through the preset model; The preset model in S4 is specifically as follows: Assume the sensor acquisition period is Sampling interval The time-series dataset collected by the temperature and humidity sensor is ;in, The total number of time series data. They represent the first Humidity and temperature at each data collection point; extraction of time-series dataset. The core features are as follows: Humidity fluctuation range : ， in, For time series datasets Humidity time-series dataset; Humidity is corrected by temperature: ， in, This is the humidity value after temperature correction; This is the temperature influence coefficient, a constant calibrated through experimental / engineering experience; Reference temperature; Calculate the duration of high humidity : ， in, For indicator functions; The high humidity risk threshold is a critical humidity value calibrated through experiments. Construct a risk index R, using dynamic weighted feature fusion: ， in, This is the humidity fluctuation weighting coefficient; This is the critical value for humidity fluctuation; This is the cumulative weighting coefficient for high humidity. This refers to the critical duration of high humidity. Extreme humidity weighting coefficient; This is the corrected maximum humidity value; Risk baseline humidity; The span of the high humidity zone.

2. The method for fire prevention, corrosion protection, and condition monitoring of steel wire rope slings for suspension bridges according to claim 1, characterized in that, The dry film thickness of the epoxy primer in S2 is controlled within... .

3. The method for fire prevention, corrosion protection, and condition monitoring of steel wire rope slings for suspension bridges according to claim 1, characterized in that, The epoxy primer in S2 achieves bottom-layer corrosion protection through the sacrificial anode effect of zinc powder or the pore sealing effect.

4. The method for fire prevention, corrosion protection, and condition monitoring of steel wire rope slings for suspension bridges according to claim 1, characterized in that, The fiber cloth interlayer reinforcement process in S2 is as follows: after each 2-3mm thick coating is applied, a layer of fiber reinforcement material is laid. The fiber weaving form is selected as plain weave, satin weave, or mesh structure according to the convenience of construction.

5. The method for fire prevention, corrosion protection, and condition monitoring of steel wire rope slings for suspension bridges according to claim 1, characterized in that, In S3, the sealing mold and the surface of the sling are radially sealed by a rubber sealing ring. The mold is provided with one main grouting inlet and two to three venting outlets in the axial direction.

6. The method for fire prevention, corrosion protection, and condition monitoring of steel wire rope slings for suspension bridges according to claim 1, characterized in that, The specific method for strengthening cathodic protection in S4 is as follows: Install a sealed injection container at both ends outside the area, with a flow channel at the bottom of the container that fits into the surface of the sling; inject cathodic protection coating with a zinc powder content >90% into the container, and apply an auxiliary pressure of 0.1-0.3MPa to promote coating penetration; after standing for 2-4 hours to allow the coating to fully penetrate into the gaps between the steel wires, remove the container and clean the surface residue to form a sacrificial anode protection layer.

7. The method for fire prevention, corrosion protection, and condition monitoring of steel wire rope slings for suspension bridges according to claim 1, characterized in that, The specific feedback of the early warning signal in S4 is as follows: according to The value matches a preset threshold range to provide early warning signal feedback; the early warning signals include: green no warning signal, yellow level 3 warning signal, orange level 2 warning signal, and red level 1 warning signal; When a green warning signal is output, the structure is in a low-risk state, and the terminal displays "stable environment, low corrosion risk". No additional intervention is required, and the regular monitoring frequency should be maintained continuously. When a yellow Level 3 warning signal is issued, the risk probability is in the range of 30%-60%. In addition to displaying the warning level, the terminal will simultaneously push characteristic data. When an orange level 2 warning signal is output, the risk probability reaches 60%-80%. An automatic pop-up window will be displayed and a text message will be sent to the operation and maintenance terminal. High-risk items will be highlighted in the characteristic data, and a comprehensive test will be required within 48 hours, including the integrity of the fireproof section coating and the cathodic protection potential test. When a red Level 1 warning signal is issued, indicating a risk probability of ≥80%, an audible and visual alarm will be activated, the location information of high-risk monitoring points will be locked, emergency response suggestions will be pushed out, and emergency repair resources will be coordinated to ensure intervention and handling within 24 hours.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, The computer program is executed by a processor as described in any one of claims 1-7: a method for fire prevention, corrosion protection, and condition monitoring of steel wire rope slings for suspension bridges.

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