阅读说明：本技术 涂覆防火涂料的钢拉索耐火极限测试装置及测试方法 (Steel cable fire resistance limit testing device coated with fireproof coating and testing method ) 是由 王广勇 刘人杰 刘维华 于 2021-08-05 设计创作，主要内容包括：本发明涉及一种涂覆防火涂料的钢拉索耐火极限测试装置及测试方法,属于耐火测试技术领域,包括高温试验炉,还包括炉盖、加载系统以及加载架支撑系统；所述加载系统包括加载架及穿心千金顶；所述加载架为多组矩形钢质加载架组合而成；加载架中间穿设有钢拉索,钢拉索两端穿出加载架两侧并固定在所述穿心千金顶上；所述加载架内设置有循环水,其表面还设置有循环水保护系统。本发明将耐火极限测试的钢拉索应用范围大大扩大,有效解决了工程中拉索耐火极限测试的难题。(The invention relates to a device and a method for testing the fire resistance limit of a steel cable coated with fireproof paint, belonging to the technical field of fire resistance testing, and comprising a high-temperature test furnace, a furnace cover, a loading system and a loading frame supporting system; the loading system comprises a loading frame and a piercing thousand-gold top; the loading frame is formed by combining a plurality of groups of rectangular steel loading frames; a steel cable penetrates through the middle of the loading frame, and two ends of the steel cable penetrate through two sides of the loading frame and are fixed on the piercing gold top; and circulating water is arranged in the loading frame, and a circulating water protection system is also arranged on the surface of the loading frame. The invention greatly expands the application range of the steel stay cable for the fire endurance test, and effectively solves the problem of the fire endurance test of the stay cable in engineering.)

1. The utility model provides a coating fire retardant coating's steel cable fire endurance testing arrangement, includes high temperature test stove (1), its characterized in that: the furnace further comprises a furnace cover (2), a loading system (3) and a loading frame supporting system (4); the loading system (3) is arranged at the top of the high-temperature test furnace (1), a furnace cover (2) is arranged at the top of the loading system (3), and the bottom of the loading system (3) is supported on a loading frame supporting system (4) around the high-temperature test furnace (1);

the loading system (3) comprises a loading frame (31) and a piercing thousand-gold top (32); the loading frame (31) is formed by combining a plurality of groups of rectangular steel loading frames; a steel cable (5) penetrates through the middle of the loading frame (31), and two ends of the steel cable (5) penetrate through two sides of the loading frame (31) and are fixed on the through-core thousand-gold crown (32); the surface of the steel inhaul cable (5) is coated with fireproof paint;

circulating water is arranged in the loading frame (31), a circulating water protection system is further arranged on the surface of the loading frame, and the circulating water protection system is composed of a water inlet pipe (311) and a steam exhaust pipe (312) which are arranged on the top surface of the loading frame (31), a water drain pipe (313) and a water level observation pipe (314) which are arranged at the bottom of the side surface of the loading frame (31).

2. The steel cable fire endurance testing apparatus coated with fireproof paint of claim 1, wherein: the loading frame supporting system (4) is composed of a section steel rectangular frame (41) and hydraulic supporting legs (42) arranged at the bottoms of four corners.

3. The steel cable fire endurance testing apparatus coated with fireproof paint of claim 2, wherein: the section steel rectangular frame (41) is formed by welding four I-shaped steels.

4. The steel cable fire endurance testing apparatus coated with fireproof paint of claim 1, wherein: and a temperature measuring device is also arranged in the loading frame (31).

5. The steel cable fire endurance testing apparatus coated with fireproof paint of claim 1, wherein: the steam exhaust pipe (312) is of a right-angle step type, and the water inlet pipe (311) and the water level observation pipe (314) are both of an L type.

6. The steel cable fire endurance testing apparatus coated with fireproof paint of claim 1, wherein: the number of the steam exhaust pipes (312) is 3, and the number of the water inlet pipe (311), the number of the water outlet pipe (313) and the number of the water level observation pipes (314) are all 1.

7. The steel cable fire endurance testing apparatus coated with fireproof paint of claim 6, wherein: the 3 steam exhaust pipes (312) are respectively arranged at three corners of the loading frame (31), and the water inlet pipe (311) is arranged at the other corner; the water level observation pipe (314) and the water inlet pipe (311) are arranged at the same corner and correspond to each other up and down; the drain pipe (313) is disposed at a corner diagonally opposite to the inlet pipe (311).

8. The steel cable fire endurance testing apparatus coated with fireproof paint of claim 1, wherein: the diameter of the steel inhaul cable (5) is 20 mm-200 mm.

9. A method for testing the fire endurance testing apparatus of a steel cable coated with a fire retardant coating according to any one of claims 1 to 8, comprising the steps of:

the method comprises the following steps: calculating the prestress loss to obtain the tension control stress of the steel stay cable (5);

considering that prestress loss occurs during the maintenance of the fireproof coating, calculating the prestress loss caused by stress relaxation during the maintenance and the prestress loss caused by the shrinkage of the penetrating kilo-gold top according to the existing prestress loss calculation theory, thereby calculating the tension control stress;

step two: assembling a steel cable fire endurance testing device, tensioning a steel cable (5) on a loading frame (31) to the tensioning control stress, and locking the tension at the moment;

step three: coating fireproof paint on the steel inhaul cable (5) and maintaining;

coating a thin-coating type or thick-coating type steel structure fireproof coating on the steel inhaul cable (5); keeping the prestress of the steel cable (5) not less than the working stress of the steel cable (5) during maintenance;

step four: tensioning again after the maintenance is qualified to enable the stress of the steel stay cable (5) to reach the working stress;

after the fireproof coating is well maintained, the loading frame (31) is installed on the high-temperature test furnace (1), the loading system (3) is started to recover loading, and the applied pulling force is equal to the working stress of the steel inhaul cable (5);

step five: and (3) carrying out a fire endurance test while the steel inhaul cable (5) bears working stress to obtain the fire endurance.

10. The test method of claim 9, wherein: the working stress of the steel cable (5) is 3000kN in the fire endurance test.

Technical Field

The invention relates to a device and a method for testing the fire resistance limit of a steel cable coated with a fireproof coating, and belongs to the technical field of fire resistance testing.

Background

At present, in the field of testing the fire endurance of steel cable members, the fire endurance test of steel cable members without steel structure fireproof coating can be generally carried out, and the size of the steel cable members is limited to a small diameter. At present, the fire endurance test experiment about the steel inhaul cable member has a great defect, and the requirement of the inhaul cable fire endurance test in an actual engineering structure cannot be met. The prior steel cable fire endurance testing technology has the following defects:

the prior art can only complete the fire endurance test of a steel stay cable component with a smaller diameter, but cannot complete the fire endurance test of a steel stay cable component with a larger diameter.

The existing tension testing machine for testing the fire endurance of the steel cable member is a conventional tension testing machine, the high-temperature furnace is a small-size high-temperature furnace matched with the tension testing machine, the fire endurance of the cable member with a small size can only be tested, and the fire endurance testing requirement of the cable member with a large size in engineering can not be met.

The current technology can only complete the fire endurance of the steel cable component without coating the fireproof paint, and can not complete the fire endurance test of the steel structure fireproof paint component.

For steel cable members, whether thick fireproof coatings or thin fireproof coatings are adopted, the fireproof coatings are coated after tensioning is finished, then maintenance of the fireproof coatings is carried out, and then the fire resistance limit test can be carried out. The more 60 days or so the curing time of the coating is, the pretension force of the stay cable needs to be kept basically unchanged in the curing time. The existing method cannot realize that the steel cable is stretched until the steel cable is pre-tensioned and then is coated with the fireproof coating, and cannot realize that the steel cable always keeps the pre-tensioning force during the maintenance of the fireproof coating. In a word, the current method cannot realize the test of the fire endurance of the stay rope coated with the fireproof coating.

In engineering, especially in building engineering, steel cables as load-bearing members have fire-resistant limit requirements, and the steel cables need to be protected from fire if the fire-resistant limit requirements are met, and thick or thin fire-resistant coatings are generally adopted. The fire endurance of the steel cable member coated with the fireproof coating needs to be tested in engineering, but the existing technical method can only complete the fire endurance test of the steel cable member with a smaller size and without the fireproof coating, cannot complete the fire endurance test of the steel cable member with a larger size, cannot complete the fire endurance test of the steel cable member coated with the fireproof coating, and a new method for completing the fire endurance test of the steel cable member coated with the fireproof coating is urgently needed to be provided.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a device and a method for testing the fire resistance limit of a steel cable coated with a fireproof coating, which are used for solving the problem of testing the fire resistance limit of a large-size steel cable component coated with the fireproof coating.

In order to achieve the purpose, the invention adopts the following technical scheme:

a steel cable fire endurance testing device coated with fireproof coating comprises a high-temperature test furnace, a furnace cover, a loading system and a loading frame supporting system; the loading system is arranged at the top of the high-temperature test furnace, a furnace cover is arranged at the top of the loading system, and the bottom of the loading system is supported on a loading frame supporting system around the high-temperature test furnace;

the loading system comprises a loading frame and a piercing thousand-gold top; the loading frame is formed by combining a plurality of groups of rectangular steel loading frames; a steel cable penetrates through the middle of the loading frame, and two ends of the steel cable penetrate through two sides of the loading frame and are fixed on the piercing gold top; the surface of the steel cable is coated with fireproof paint;

the loading frame is internally provided with circulating water, the surface of the loading frame is also provided with a circulating water protection system, and the circulating water protection system is composed of a water inlet pipe and a steam exhaust pipe which are arranged on the top surface of the loading frame, and a water drain pipe and a water level observation pipe which are arranged at the bottom of the side surface of the loading frame.

Furthermore, the loading frame supporting system is composed of a section steel rectangular frame and hydraulic support legs arranged at the bottoms of four corners.

Furthermore, the section steel rectangular frame is formed by welding four I-shaped steels.

Further, a temperature measuring device is further arranged in the loading frame.

Further, the steam exhaust pipe is right-angled step type, and inlet tube and water level observation pipe are the L type.

Furthermore, the steam exhaust pipe is 3, and inlet tube, drain pipe, water level observation pipe are 1.

Further, 3 steam exhaust pipes are respectively arranged at three corners of the loading frame, and the water inlet pipe is arranged at the other corner; the water level observation pipe and the water inlet pipe are arranged at the same corner and correspond to each other up and down; the drain pipe is arranged on a corner diagonally opposite to the water inlet pipe.

Further, the diameter of the steel inhaul cable is 20 mm-200 mm.

The testing method of the steel cable fire endurance testing device coated with the fireproof coating comprises the following steps:

the method comprises the following steps: calculating the prestress loss to obtain the tension control stress of the steel cable;

considering that prestress loss occurs during the maintenance of the fireproof coating, calculating the prestress loss caused by stress relaxation during the maintenance and the prestress loss caused by the shrinkage of the penetrating kilo-gold top according to the existing prestress loss calculation theory, thereby calculating the tension control stress;

step two: assembling a steel cable fire endurance testing device, tensioning the steel cable on a loading frame to the tensioning control stress, and locking the tension at the moment;

step three: coating fireproof paint on the steel cable and maintaining;

coating a thin-coating or thick-coating fireproof coating for a steel structure on a steel cable; maintaining the prestress of the steel cable not less than the working stress of the steel cable during maintenance;

step four: tensioning again after the maintenance is qualified to enable the stress of the steel stay rope to reach the working stress;

after the fireproof coating is well maintained, the loading frame is installed on a high-temperature test furnace, a loading system is started to recover loading, and the applied tension is equal to the working stress of the steel stay cable;

step five: and (4) carrying out a fire endurance test while the steel cable is subjected to working stress to obtain the fire endurance.

Further, the working stress of the steel cable in the fire endurance test was 3000 kN.

Compared with the prior art, the invention has the following beneficial effects:

compared with the prior art, the technical scheme can firstly complete the fire endurance test of a large-diameter steel cable test piece. Particularly, the technical scheme can complete the fire endurance test task of the stay rope test piece coated with the fireproof coating widely applied in engineering, while the prior technical scheme can only complete the fire endurance test of the steel stay rope test piece not coated with the fireproof coating and cannot complete the fire endurance test of the stay rope test piece coated with the fireproof coating. Therefore, the technical scheme greatly expands the application range of the stay cable for the fire endurance test, and effectively solves the problem of the stay cable fire endurance test in engineering. The method comprises the following specific steps:

fire-resistant limit test system for large-size inhaul cable test piece

A steel cable fire resistance limit test system consisting of a large fire high-temperature test furnace and a large loading frame is established, and a fire resistance limit test of a large-size steel cable test piece can be completed.

Working principle and working process for fire endurance test of steel stay cable coated with fireproof coating

The maintenance time of the fireproof coating is long, and the steel cable test piece needs to bear pretension force during coating the fireproof coating, maintenance and fire. The stretching of the stay cable, the coating of the fireproof coating, the maintenance of the fireproof coating and the maintenance of the prestress of the stretched stay cable are one of the key invention points of the technology.

Circulating water protection method of loading system

In order to keep the loading system at a lower temperature, a circulating water protection method is designed to keep the temperature of the loading system not more than 50 ℃ during a fire resistance test.

Drawings

FIG. 1 is a schematic structural view of a steel cable fire endurance testing device of the present invention;

FIG. 2 is a schematic view of a loading system of the present invention;

FIG. 3 is a test flow chart of the steel cable fire endurance testing device of the present invention

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

Referring to fig. 1-2, the device for testing the fire endurance of the steel cable coated with the fireproof coating comprises a high-temperature test furnace 1, a furnace cover 2, a loading system 3 and a loading frame supporting system 4. The loading system 3 is arranged at the top of the high-temperature test furnace 1, the furnace cover 2 is arranged at the top of the loading system 3, the bottom of the loading system 3 is supported on a loading frame supporting system 4 around the high-temperature test furnace 1, and the loading frame supporting system 4 is composed of a section steel rectangular frame 41 and hydraulic supporting legs 42 arranged at the bottoms of four corners. The section steel rectangular frame 41 is formed by welding four I-shaped steels.

The loading system 3 includes a loading frame 31 and a piercing jack 32. The loading frame 31 is formed by combining a plurality of groups of rectangular steel loading frames. The middle of the loading frame 31 is provided with a steel cable 5 in a penetrating way, and the diameter of the steel cable 5 is 20 mm-200 mm. Two ends of the steel cable 5 penetrate through two sides of the loading frame 31 and are fixed on the punching thousand-gold top 32. The surface of the steel cable 5 is coated with fireproof paint.

As shown in fig. 2, the inside of the loading frame 31 is provided with circulating water, and the surface of the loading frame 31 is also provided with a circulating water protection system, wherein the circulating water protection system is composed of a water inlet pipe 311 and a steam exhaust pipe 312 arranged on the top surface of the loading frame 31, a water outlet pipe 313 and a water level observation pipe 314 arranged on the bottom of the side surface of the loading frame 31.

Since the loading frame 31 is made of high-strength steel, the steel itself is not fire-resistant, and the loading frame 31 cannot bear the high-temperature action. Therefore, a circulating water protection system of the loading frame 31 is designed, circulating water is adopted, and the water in the loading frame is guaranteed not to exceed 50 ℃, so that the strength of steel at high temperature and the bearing capacity of the loading frame 31 are guaranteed to be consistent with those at normal temperature, and the safety of the loading frame 31 is guaranteed. The circulating water protection system forms water flow in the loading frame 31, tap water enters the loading frame 31 through the water inlet pipe 311, and is discharged out of the loading frame 31 through the water outlet pipe 313.

In this embodiment, a temperature measuring device is further disposed in the loading frame 31. Further, the steam exhaust pipe 312 is a right-angled step type, and the water inlet pipe 311 and the water level observation pipe 314 are L-shaped. Further, there are 3 steam exhaust pipes 312, and 1 water inlet pipe 311, a water discharge pipe 313, and a water level observation pipe 314. The 3 steam exhaust pipes 312 are respectively arranged at three corners of the loading frame 31, and the water inlet pipe 311 is arranged at the other corner. The water level observation pipe 314 is disposed at the same corner as the water inlet pipe 311, and corresponds to the water inlet pipe. The drain pipe 313 is provided on a corner diagonally opposite to the inlet pipe 311.

As shown in fig. 3, the testing method of the fire endurance testing apparatus for the steel cable coated with the fireproof paint of the embodiment includes the following steps:

the method comprises the following steps: and calculating the prestress loss to obtain the tension control stress of the steel cable 5.

Considering that prestress loss occurs during the maintenance of the fireproof coating, the prestress loss caused by stress relaxation during the maintenance and the prestress loss caused by the shrinkage of the penetrating kilo-gold top are calculated according to the existing prestress loss calculation theory, so that the tension control stress is calculated.

Step two: and assembling the steel cable fire endurance testing device, tensioning the steel cable 5 on the loading frame 31 to tension control stress, and locking the tension at the moment.

Step three: and (3) coating a fireproof coating on the steel cable 5 and maintaining.

And coating a thin-coating type or thick-coating type steel structure fireproof coating on the steel cable 5. And keeping the prestress of the steel cable 5 not less than the working stress of the steel cable 5 during maintenance.

Step four: and tensioning again after the maintenance is qualified to ensure that the stress of the steel stay cable 5 reaches the working stress.

After the fireproof coating is well maintained, the loading frame 31 is installed on the high-temperature test furnace 1, the loading system 3 is started to recover loading, and the applied pulling force is equal to the working stress of the steel inhaul cable 5.

Step five: the steel inhaul cable 5 is subjected to a working stress and a fire endurance test is carried out at the same time, so that the fire endurance is obtained. The working stress of the steel cable 5 in the endurance test was 3000 kN.

The above embodiments are only preferred embodiments of the present invention, but are not limited to the above embodiments, and it should be understood that various changes, modifications, substitutions and alterations can be made by those skilled in the art without departing from the principle and spirit of the present invention, and fall within the protection scope of the present invention.