A test device for fire resistance research of bridge cable

Abstract

This utility model relates to the field of fire resistance testing technology for bridge cables, and more particularly to a test device for studying the fire resistance of bridge cables. Its technical solution includes a gas furnace, a fire-prone furnace body, a temperature detection system, and a smoke and dust treatment system. The gas furnace mainly consists of a gas stove, a blower, a gas cylinder, and a gas pressure reducing valve. The fire-prone furnace body consists of an insulation section, a smoke exhaust section, a specimen section, and a top cover. The temperature detection system consists of a back-temperature thermocouple, a fire-prone thermocouple, and a paperless recorder. The smoke and dust treatment system consists of a smoke and dust collection hood and an exhaust fan. This utility model, through the integration of a modular furnace structure and a parameterized testing method, solves the problems of existing technologies that use physical cables for fire protection followed by combustion testing in a fire, resulting in large volume, resource waste, high cost per test, and significant discrepancies between test results and actual detection data, which are detrimental to the experimental research on the fire resistance performance of bridge cables.

Description

Technical Field

[0001] This utility model relates to the field of fire resistance testing technology for bridge cables, and in particular to a test device for studying the fire resistance of bridge cables. Background Technology

[0002] For long-span bridges that need to cross major rivers, oceans, and canyons, cable-stayed bridges are often the first choice for bridge designers. The bridge cable is the lifeline of a cable-stayed bridge, and national standards require that its durability design be no less than 100 years, making it a non-replaceable component.

[0003] Currently, with rapid economic development and an increase in vehicle ownership, traffic accidents occur frequently, especially those involving tank trucks carrying flammable materials such as natural gas, liquefied petroleum gas, and organic solvents. These vehicles are highly susceptible to ignition in accidents, and the temperature at the fire scene can rise to as high as 1100℃ in a very short time. If a fire occurs on a cable-stayed bridge, it will cause significant damage to the main cable. In recent years, there has been considerable research on fire-resistant technology for bridge cables. One method involves applying fire-retardant coatings to bundles of solid main cable sections and then placing them in a furnace for fire resistance testing. However, this method is costly to produce and conducts tests, and the specimens are difficult to protect, hindering fire resistance research. Simple burning tests using alcohol lamps or alcohol torches yield poor reproducibility and can only provide qualitative analysis of the materials, not quantitative research on cable fire resistance.

[0004] Patent CN 117192023 discloses a method for simulating on-site fire combustion test of segmental solid cable with fire-resistant sealing protection. The method involves wrapping solid cable with fire-resistant seal and then conducting a fire resistance test in a simulated fire scene. Patent CN100585377C relates to an improvement on the electric furnace and testing method for on-site testing of intumescent fire-retardant coatings. It uses an electric furnace for heating, simulating a fire scene according to the standard temperature rise curve specified in GB / T 9798.1, with the test endpoint being a sample back temperature of 580℃. It is mainly used for studying the fire resistance performance of intumescent fire-retardant coatings. However, this testing device struggles to provide a temperature rise curve for an HC fire scene, and the insulation materials and fire-retardant adhesives for cables are difficult to fix on a steel plate 47.297mm long and 20-300mm wide, making it unsuitable for fire resistance testing of bridge cables. Existing technologies involve fire-protecting the cable itself before placing it in a fire scene for combustion testing, resulting in large volume, resource waste, high testing costs, and significant discrepancies between test results and actual detection data, hindering research on the fire resistance performance of bridge cables. Therefore, those skilled in the art provide a testing device for fire resistance research of bridge cables to address the problems mentioned in the background art. Utility Model Content

[0005] The purpose of this invention is to address the problems existing in the background technology by proposing a test device for fire resistance research of bridge cables. The technical problem to be solved by this invention is to design and manufacture a small-scale test device for fire resistance of bridge cables suitable for laboratory applications, which is safe and environmentally friendly, has good reproducibility of test results, and the test results are closer to the actual test data.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a test device for fire resistance research of bridge cables, comprising a gas furnace, a fire furnace body, a temperature detection system, and a smoke and dust treatment system. The fire furnace body is placed above the flame of the gas furnace, the smoke and dust treatment system is placed at a certain height above the fire furnace body to collect the smoke and dust generated during the experiment, and the temperature monitoring system is used to detect and record the temperature of the experimental steel pipe mixed specimen and the temperature inside the fire furnace body.

[0007] The gas stove mainly consists of a gas cooker, a blower, a gas tank, and a gas pressure reducing valve;

[0008] The furnace body of the fire site is mainly composed of multiple short sections with insulation material. The short section assembly, from bottom to top, consists of an insulation short section, a smoke exhaust short section, a test piece short section, and a top cover.

[0009] The temperature detection system mainly consists of a back temperature thermocouple, a fire scene thermocouple, and a paperless recorder;

[0010] The dust treatment system consists of a dust collection hood, an exhaust fan, and an exhaust pipe.

[0011] Preferably, the inner side of the insulation section is provided with a stainless steel cylindrical frame, and the two ends of the cylinder are reinforced with flanges. The stainless steel cylindrical frame is surrounded by ceramic insulation cotton, and the number of ceramic insulation cotton layers is 1 to 3. By using the stainless steel frame and 1 to 3 adjustable ceramic cotton layers, modular insulation adjustment is achieved, a stable thermal environment is constructed, the axial heat conduction of the section is precisely controlled, and the temperature gradient runaway problem caused by the fixed insulation layer is avoided. The flange reinforcement structure improves the deformation resistance of the section and avoids the sealing failure caused by the thermal expansion of the furnace body.

[0012] Preferably, the inner wall of the exhaust section is a stainless steel cylindrical frame II, reinforced at both ends by flanges II. The stainless steel cylindrical frame II is surrounded by ceramic insulation cotton II, and multiple exhaust holes are opened around the cylinder. The center of each exhaust hole is 30mm to 60mm vertically from the lowest point of the test specimen, preferably 40mm. The 40mm distance between the exhaust holes and the specimen allows for directional discharge of combustion products, balancing fire pressure and flue gas flow, maintaining combustion stability, and preventing sudden temperature drops caused by open exhaust holes. The ceramic insulation cotton II, combined with the stainless steel cylindrical frame II, lowers the surface temperature of the section, avoiding the risk of burns during operation.

[0013] Preferably, the inner side of the specimen short section is a stainless steel cylindrical frame three, and the two ends of the cylinder are reinforced with flanges three. The stainless steel cylindrical frame three is surrounded by ceramic insulation cotton three. The upper end of the stainless steel cylindrical frame three has two symmetrically distributed notches. The bottom of the notches is arc-shaped. The inner diameter of the notches can accommodate the specimen without exceeding the upper surface of the specimen short section. The arc-shaped inner diameter and the symmetrically distributed notch structure ensure convenient axial insertion of the specimen, avoid the edge thermal bridging effect caused by the clamp, reduce the circumferential temperature difference of the specimen, and the insulation cotton filling reduces the heat leakage rate at the notches, thus improving the airtightness.

[0014] Preferably, the lower end of the top cover is provided with a stainless steel circular cover, which covers the upper opening of the short section of the specimen. The stainless steel circular cover is internally lined with ceramic insulation cotton. The detachable circular cover and the adaptive ceramic insulation cotton form a dynamic pressure compensation system, achieving a dual function of top sealing and adaptive adjustment of thermal expansion. This avoids the positive pressure imbalance in the combustion chamber caused by a fixed top cover, reduces the pressure fluctuation range, and the dual insulation reduces the top heat loss rate, improving upon a single-layer structure.

[0015] Preferably, an experimental steel pipe is inserted into the notch.

[0016] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0017] This utility model adopts a split-type fire station furnace design. Through the combination of insulation short sections, smoke exhaust short sections, and specimen short sections, the equipment size is reduced and the test cost is lowered while ensuring test accuracy. The innovatively designed smoke exhaust short section is controlled by specific aperture and position parameters (40mm preferred distance). Combined with dynamic gas adjustment technology, it can rapidly raise the fire station temperature to 1000℃ within 10 minutes and conform to the HC heating curve. The temperature control accuracy reaches ±25℃. The multi-layer insulation structure reduces the heat loss rate and improves the insulation performance compared with traditional open combustion devices. The unique notch-type specimen fixing structure combined with ceramic cotton sealing technology ensures the installation and positioning accuracy of the specimen and effectively isolates edge thermal interference.

[0018] The detection method establishes a termination standard of 300℃ back temperature, which is closer to the actual failure mechanism of cables than the traditional 580℃ standard. The deviation rate of test data is reduced. After verification by 5 sets of comparative tests, the test results of this device have a high correlation with the test data of actual cables, and the deviation of repeated tests is small. It provides a reliable test platform for the research and development of fire-resistant materials, reduces the cost of a single test, improves the detection efficiency, and has significant technical and economic benefits. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the main cross-sectional structure of this utility model;

[0020] Figure 2This is a schematic diagram of the main cross-sectional structure of this utility model;

[0021] Figure 3 This is a schematic diagram of the main structure of the dust treatment system of this utility model;

[0022] Figure 4 This is a side sectional view of the furnace body of the present invention.

[0023] Figure 5 For the present utility model Figure 1 Schematic diagrams of the main sectional view and side view of the experimental steel pipe;

[0024] Figure 6 This is a schematic diagram of the main cross-sectional structure of the thermal insulation short section of this utility model;

[0025] Figure 7 This is a schematic diagram of the main cross-sectional structure of the smoke exhaust section of this utility model;

[0026] Figure 8 This is a side sectional view of the short section of the specimen of this utility model and an enlarged schematic diagram of the experimental steel pipe in this figure;

[0027] Figure 9 This is a schematic diagram of the main cross-sectional structure of the top cover of this utility model.

[0028] 100. Gas stove; 101. Gas cooker; 102. Blower; 103. Gas cylinder; 104. Pressure reducing valve;

[0029] 200. Furnace body for fire scene; 201. Insulation short section; 201.a. Stainless steel cylindrical frame; 201.b. Ceramic insulation cotton; 201.c. Flange plate;

[0030] 202. Smoke exhaust section; 202.a. Two ceramic insulation cotton pieces; 202.b. Two stainless steel cylindrical frames; 202.c. Two flanges; 202.d. Smoke exhaust port;

[0031] 203. Specimen short section; 203.a. Stainless steel cylindrical frame three; 203.b. Flange three; 203.c. Ceramic insulation cotton three; 203.d. Notch;

[0032] 204, top cover; 204.a, stainless steel round cover; 204.b, ceramic insulation cotton (four layers);

[0033] 300. Temperature detection system; 301. Paperless recorder; 302. Fire scene thermocouple; 303. Back temperature thermocouple;

[0034] 400. Smoke and dust treatment system; 401. Smoke and dust collection hood; 402. Exhaust fan; 403. Waste gas pipe; 500. Experimental steel pipe. Detailed Implementation

[0035] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0036] Please see Figures 1 to 9 The present invention provides four embodiments:

[0037] Example 1:

[0038] An experimental device for fire resistance research of bridge cables includes a gas furnace 100, a fire furnace body 200, a temperature detection system 300, and a smoke and dust treatment system 400. The fire furnace body 200 is placed above the flame of the gas furnace 100. The smoke and dust treatment system 400 is placed at a certain height above the fire furnace body 200 to collect the smoke and dust generated during the experiment. The temperature monitoring system is used to detect and record the temperature of the experimental steel pipe 500 mixed specimen and the temperature inside the fire furnace body 200.

[0039] The furnace body 200 is mainly composed of multiple short sections with insulation material. The short section assembly, from bottom to top, consists of insulation short section 201, smoke exhaust short section 202, test piece short section 203, and top cover 204.

[0040] The temperature detection system 300 mainly consists of a back temperature thermocouple 303, a fire scene thermocouple 302, and a paperless recorder 301;

[0041] The dust collection system 400 consists of a dust collection hood 401, an exhaust fan 402, and a waste gas pipe 403;

[0042] The inner side of the insulation short section 201 is provided with a stainless steel cylindrical frame 201.a, and the two ends of the cylindrical frame are reinforced with flanges 201.c. The stainless steel cylindrical frame 201.a is surrounded by ceramic insulation cotton 201.b, and the number of ceramic insulation cotton 201.b is 1 to 3.

[0043] The inner wall of the exhaust section 202 is a stainless steel cylindrical frame 202.b, and the two ends of the cylinder are reinforced with flanges 202.c. The stainless steel cylindrical frame 202.b is surrounded by ceramic insulation cotton 202.a, and multiple exhaust holes 202.d are opened around the cylinder. The vertical distance between the center of the exhaust hole 202.d and the lowest point of the test specimen is 30mm to 60mm, preferably 40mm.

[0044] The inner side of the specimen short section 203 is a stainless steel cylindrical skeleton 203.a, and the two ends of the cylindrical skeleton are reinforced by flanges 203.b. The stainless steel cylindrical skeleton 203.a is surrounded by ceramic insulation cotton 203.c. The upper end of the stainless steel cylindrical skeleton 203.a has two symmetrically distributed notches 203.d. The bottom of the notches 203.d is arc-shaped. The inner diameter of the notches 203.d can accommodate the specimen and the top does not exceed the upper surface of the specimen short section 203.

[0045] The lower end of the top cover 204 is provided with a stainless steel round cover 204.a, which covers the upper opening of the short section 203 of the specimen. Ceramic insulation cotton 204.b is installed inside the stainless steel round cover 204.a.

[0046] A 500mm experimental steel pipe is inserted into the notch 203.d.

[0047] This embodiment establishes a standardized fire resistance performance evaluation system based on HC heating curve simulation and multi-parameter coupled control principles.

[0048] In this embodiment, the temperature detection system 300 employs dual-channel monitoring with K-type thermocouples. The back-temperature thermocouple 303 is inserted into the inner wall of the steel pipe for contact temperature measurement, while the fire-time thermocouple 302 extends into the flame core area through the smoke exhaust port 202.d. Combined with the paperless recorder 301 collecting data every 3 seconds, the accuracy is improved compared to traditional manual recording. During the ignition phase, a gradual gas supply strategy is adopted, with an initial damper opening of 10% to ensure safe ignition, and the system adjusts to the optimal gas supply ratio (gas flow rate 1.2 m³ / s) within 30 seconds. 3 / h, wind pressure 200Pa), to achieve a rapid temperature rise of 1000℃ in the fire area within 10 minutes and conform to the HC curve (goodness of fit R). 2 =0.98);

[0049] The back temperature curve was monitored in real time during the test. When the threshold of 300℃ was reached, the termination program was automatically triggered. This standard is closer to the failure point of the cable PE sheath than the traditional 580℃, which improves the validity of the data. The data post-processing adopted the moving average algorithm to eliminate fluctuations and calculated key parameters such as fire resistance time (average of 96.6 min) and heating rate (8.2℃ / min). The coefficient of variation of the five test groups was only 2.1%, which proved that the device has excellent reproducibility.

[0050] The safety control system includes a dual-redundant shutdown procedure, with a 5-minute interval between the sequential shutdown of the gas valve, pressure reducing valve 104, and blower 102, ensuring complete combustion of residual gas and maintaining a CO concentration consistently below 10 ppm. This method reduces energy consumption per test, and the correlation coefficient between the experimental data and the actual cable combustion test reaches 0.96, providing a high-confidence platform for the development of fire-resistant materials.

[0051] Example 2:

[0052] It includes a gas furnace 100, a fire furnace body 200, a temperature detection system 300, and a smoke and dust treatment system 400. The fire furnace body 200 is placed above the flame of the gas furnace 100. The smoke and dust treatment system 400 is placed at a certain height above the fire furnace body 200 to collect the smoke and dust generated in the experiment. The temperature monitoring system is used to detect and record the temperature of the experimental steel pipe 500 mixed specimen and the temperature inside the fire furnace body 200.

[0053] The gas stove 100 mainly consists of a gas stove 101, a blower 102, a gas tank 103, and a gas pressure reducing valve 104;

[0054] The furnace body 200 is mainly composed of multiple short sections with insulation material. The short section assembly, from bottom to top, consists of insulation short section 201, smoke exhaust short section 202, test piece short section 203, and top cover 204.

[0055] The temperature detection system 300 mainly consists of a back temperature thermocouple 303, a fire scene thermocouple 302, and a paperless recorder 301;

[0056] The inner side of the insulation short section 201 is provided with a stainless steel cylindrical frame 201.a, and the two ends of the cylindrical frame are reinforced with flanges 201.c. The stainless steel cylindrical frame 201.a is surrounded by ceramic insulation cotton 201.b, and the number of ceramic insulation cotton 201.b is 1 to 3.

[0057] The inner wall of the exhaust section 202 is a stainless steel cylindrical frame 202.b, and the two ends of the cylinder are reinforced with flanges 202.c. The stainless steel cylindrical frame 202.b is surrounded by ceramic insulation cotton 202.a, and multiple exhaust holes 202.d are opened around the cylinder. The vertical distance between the center of the exhaust hole 202.d and the lowest point of the test specimen is 30mm to 60mm, preferably 40mm.

[0058] The inner side of the specimen short section 203 is a stainless steel cylindrical skeleton 203.a, and the two ends of the cylindrical skeleton are reinforced by flanges 203.b. The stainless steel cylindrical skeleton 203.a is surrounded by ceramic insulation cotton 203.c. The upper end of the stainless steel cylindrical skeleton 203.a has two symmetrically distributed notches 203.d. The bottom of the notches 203.d is arc-shaped. The inner diameter of the notches 203.d can accommodate the specimen and the top does not exceed the upper surface of the specimen short section 203.

[0059] The lower end of the top cover 204 is provided with a stainless steel round cover 204.a, which covers the upper opening of the short section 203 of the specimen. Ceramic insulation cotton 204.b is installed inside the stainless steel round cover 204.a.

[0060] A 500mm experimental steel pipe is inserted into the notch 203.d.

[0061] This embodiment establishes a standardized fire resistance performance evaluation system based on HC heating curve simulation and multi-parameter coupled control principles.

[0062] In this embodiment, the temperature detection system 300 employs dual-channel monitoring with K-type thermocouples. The back-temperature thermocouple 303 is inserted into the inner wall of the steel pipe for contact temperature measurement, while the fire-time thermocouple 302 extends into the flame core area through the smoke exhaust port 202.d. Combined with the paperless recorder 301 collecting data every 3 seconds, the accuracy is improved compared to traditional manual recording. During the ignition phase, a gradual gas supply strategy is adopted, with an initial damper opening of 10% to ensure safe ignition, and the system adjusts to the optimal gas supply ratio (gas flow rate 1.2 m³ / s) within 30 seconds. 3 / h, wind pressure 200Pa), to achieve a rapid temperature rise of 1000℃ in the fire area within 10 minutes and conform to the HC curve (goodness of fit R). 2 =0.98);

[0063] The back temperature curve was monitored in real time during the test. When the threshold of 300℃ was reached, the termination program was automatically triggered. This standard is closer to the failure point of the cable PE sheath than the traditional 580℃, which improves the validity of the data. The data post-processing adopted the moving average algorithm to eliminate fluctuations and calculated key parameters such as fire resistance time (average of 96.6 min) and heating rate (8.2℃ / min). The coefficient of variation of the five test groups was only 2.1%, which proved that the device has excellent reproducibility.

[0064] The safety control system includes a dual-redundant shutdown procedure, with a 5-minute interval between the sequential shutdown of the gas valve, pressure reducing valve 104, and blower 102, ensuring complete combustion of residual gas and maintaining a CO concentration consistently below 10 ppm. This method reduces energy consumption per test, and the correlation coefficient between the test data and the actual cable combustion test reaches 0.96, providing a high-confidence platform for the research and development of fire-resistant materials.

[0065] The dust collection system 400 consists of a dust collection hood 401, an exhaust fan 402, and a waste gas pipe 403;

[0066] During testing, the smoke and dust purification system is activated first, using a three-stage filtration system (pre-filter + HEPA + activated carbon) to achieve efficient purification of PM2.5 and solve the problem of carcinogen emissions in traditional combustion tests.

[0067] The exhaust gas treatment system of this experimental device adopts a three-stage purification process, including a dust collection hood 401, a high-temperature resistant corrugated pipe, a cyclone separator, a ceramic fiber filter, an activated carbon adsorption tower, and a catalytic combustion device, forming a complete exhaust gas treatment chain. Based on the synergistic principle of "physical interception-chemical adsorption-high-temperature decomposition," the system first collects combustion exhaust gas at a capture velocity of 15 m / s through a 304 stainless steel dust collection hood 401. This gas is then transported to the pretreatment unit via a high-temperature resistant aluminum silicate corrugated pipe (800℃ resistant). The cyclone separator, through tangential air intake, creates a centrifugal force field, removing over 90% of carbon particles >10μm, with a measured pressure drop of only 500Pa. The secondary treatment uses a porous ceramic fiber filter (0.5μm pore size, 85% porosity), achieving a PM2.5 removal efficiency of 99% at 300℃. A pulse backflushing system automatically cleans the filter every 30 minutes, ensuring the filtration resistance remains stable below 1.2 kPa.

[0068] The activated carbon adsorption tower is filled with honeycomb modified activated carbon, which adsorbs volatile organic compounds such as benzene series and aldehydes through van der Waals forces and chemical bonding. The design achieves an adsorption capacity of 35% for toluene at an empty tower flow rate of 0.3 m / s. A catalytic combustion device is installed at the end, using cordierite to support 0.3% platinum-palladium catalyst, which converts CO and unburned hydrocarbons into CO2 and H2O at 350℃. The 403 exhaust gas pipes are connected by flanges and wrapped with a 50mm thick ceramic fiber insulation layer to ensure that the system temperature is >200℃ throughout to avoid condensation and corrosion of acidic gases.

[0069] The gas supply is automatically cut off when the CO concentration exceeds 50 ppm or the pipeline temperature exceeds 600℃. The filter status is monitored in real time via a differential pressure transmitter; an audible and visual alarm is triggered when the resistance exceeds 2 kPa. The activated carbon unit uses a drawer-type design, allowing for replacement within 15 minutes. The treated exhaust gas emission standard is: particulate matter ≤ 5 mg / m³. 3 CO≤50mg / m³ 3 VOCs ≤ 30 mg / m³ 3 It complies with the GB16297-1996 Integrated Emission Standard for Air Pollutants. Compared with the traditional direct emission method, the system reduces the emission of carcinogen benzo[a]pyrene by 99.7%, reduces the formation of dioxins by about 2.3 μg-TEQ in a single test, and has an operating energy consumption of only 8 kWh / test, which is more energy-efficient than similar equipment.

[0070] Example 3:

[0071] The installation steps of the test device for studying the fire resistance of bridge cables are as follows:

[0072] S1: Preparation of fire resistance test specimens. Experimental steel pipe 500 is used as a simulated specimen for bridge cables. After the surface is cleaned, an anti-corrosion layer, aerogel felt, intumescent fire-resistant sealing tape, and protective layer are applied in sequence.

[0073] S2: Install the gas stove 100, connect the blower 102, gas cylinder 103, pressure reducing valve 104, etc. to the gas stove 101, and connect the power supply;

[0074] S3: Install the furnace body 200. On the gas stove 101, from bottom to top, install the insulation section 201, the exhaust section 202, the test piece section 203, and the top cover 204. The height of the furnace body 200 can be adjusted by adding or removing the insulation section 201 according to the height of the flame, so as to ensure that the test piece is in the outer flame of the gas and that the gas has sufficient space for combustion.

[0075] S4: Install the fire resistance test specimen, remove the top cover 204 of the fire furnace body 200, place the fire resistance test specimen at the notch 203.d of the specimen short section 203 and inside the test steel pipe 500, cover the top cover 204 of the fire furnace body 200, and plug the notch 203.d with ceramic cotton.

[0076] S5: Install the temperature detection system 300, insert the back temperature thermocouple 303 into the middle of the test steel tube 500 of the test specimen, close to the inner wall of the test steel tube 500, and plug both ends of the test steel tube 500 with ceramic cotton. Insert the fire field thermocouple 302 into the smoke exhaust hole 202.d of the smoke exhaust short section 202 and extend it to the center of the fire field. Connect the thermocouple to the paperless recorder 301 and connect the paperless recorder 301 to the power supply.

[0077] S6: Install the dust treatment system 400. Install the dust collection hood and exhaust fan in sequence above the furnace body 200 in the fire area, and connect the exhaust port to the dust purification device and the power supply.

[0078] In this embodiment, based on the principle of modular thermodynamic control, precise fire scene construction is achieved through layered assembly and parameterized adjustment. During installation, a simulated cable specimen is first prepared, and after the surface is coated with a fire-resistant layer, a test platform is built using a three-level architecture consisting of a gas furnace 100, a fire scene furnace body 200, and a smoke and dust system. The gas furnace 100 adopts a dynamic gas supply mode with a blower 102 linked to a pressure reducing valve 104. Precise control of the gas flow rate and air mixing ratio is achieved through damper adjustment. The test shows that this design can improve the gas combustion efficiency. The fire scene furnace body 200 adopts short section combination technology. The insulation short section 201 adjusts the axial thermal resistance through 1 to 3 layers of ceramic insulation cotton 201.b. Combined with the flange reinforcement structure, it ensures that the thermal expansion deformation of the furnace body is <0.1mm, solving the problem of thermal stress cracking in traditional integral furnace bodies.

[0079] The exhaust stub 202 is positioned with the optimal exhaust hole 202.d 40mm away from the specimen. It utilizes the Bernoulli effect to create negative pressure suction, shortening the measured flue gas residence time to 2s and avoiding carbon buildup interference. The specimen stub 203 adopts a notch 203.d positioning structure. Through the arc-shaped inner diameter and symmetrical distribution design, the specimen axis deviation is reduced to <0.5mm, improving positioning accuracy. During installation, the fire height is adjusted by increasing or decreasing the number of insulation stubs 201 to ensure that the specimen is located in the outer flame zone (temperature gradient 1100±50℃). Infrared thermal imaging verification shows that the specimen's heating surface is uniform. The top cover 204 uses a dynamic seal filled with ceramic insulation cotton 204.b, allowing for 3mm thermal expansion displacement and stabilizing the furnace pressure within the ±50Pa range. This installation system reduces the cost of a single test and supports furnace reconstruction within 5 minutes, improving efficiency compared to traditional physical cable tests.

[0080] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A test apparatus for fire resistance research of bridge cables, characterized in that: It includes a gas furnace (100), a fire furnace body (200), a temperature detection system (300), and a smoke and dust treatment system (400). The fire furnace body (200) is placed above the flame of the gas furnace (100). The smoke and dust treatment system (400) is placed at a certain height above the fire furnace body (200) to collect the smoke and dust generated during the experiment. The temperature monitoring system is used to detect and record the temperature of the experimental steel pipe (500) mixed specimen and the temperature inside the fire furnace body (200). The gas stove (100) mainly consists of a gas stove (101), a blower (102), a gas tank (103), and a gas pressure reducing valve (104); The furnace body (200) is mainly composed of multiple short sections with insulation material. The short section assembly is arranged from bottom to top as follows: insulation short section (201), smoke exhaust short section (202), test piece short section (203), and top cover (204). The temperature detection system (300) mainly consists of a back temperature thermocouple (303), a fire scene thermocouple (302), and a paperless recorder (301); The dust treatment system (400) consists of a dust collection hood (401), an exhaust fan (402), and a waste gas pipe (403).

2. The test device for fire resistance research of bridge cable according to claim 1, characterized in that: The inner side of the insulation short section (201) is provided with a stainless steel cylindrical frame (201.a), and the two ends of the cylindrical frame are reinforced with flanges (201.c). The stainless steel cylindrical frame (201.a) is surrounded by ceramic insulation cotton (201.b), and the number of ceramic insulation cotton (201.b) is 1 to 3.

3. The test device for fire resistance research of bridge cable according to claim 2, characterized in that: The inner wall of the exhaust section (202) is a stainless steel cylindrical frame (202.b), and the two ends of the cylinder are reinforced with flanges (202.c). The stainless steel cylindrical frame (202.b) is surrounded by ceramic insulation cotton (202.a), and multiple exhaust holes (202.d) are opened around the cylinder. The vertical distance between the center of the exhaust hole (202.d) and the lowest point of the test specimen is 30mm to 60mm, preferably 40mm.

4. The test device for fire resistance research of bridge cable according to claim 3, characterized in that: The inner side of the specimen short section (203) is a stainless steel cylindrical skeleton three (203.a), and the two ends of the cylindrical skeleton are reinforced by flange three (203.b). The stainless steel cylindrical skeleton three (203.a) is surrounded by ceramic insulation cotton three (203.c). The upper end of the stainless steel cylindrical skeleton three (203.a) has two symmetrically distributed notches (203.d). The bottom of the notches (203.d) is arc-shaped. The inner diameter of the notches (203.d) can accommodate the specimen and the top does not exceed the upper surface of the specimen short section (203).

5. The test device for fire resistance research of bridge cable according to claim 4, characterized in that: The lower end of the top cover (204) is provided with a stainless steel round cover (204.a), which covers the upper opening of the short section (203) of the specimen, and ceramic insulation cotton (204.b) is provided inside the stainless steel round cover (204.a).

6. The test device for fire resistance research of bridge cable according to claim 5, characterized in that: An experimental steel pipe (500) is inserted into the notch (203.d).

Images