High-precision measurement method and equipment for fire resistance of high-strength concrete-filled steel tube structures

Abstract

The invention relates to a high-precision measurement method and equipment for the fire resistance of high-strength steel tube concrete structures, belonging to the field of combined structure testing technology. The technical key points include: a data acquisition and calculation platform and a heating furnace; the heating furnace includes a furnace body, a distributed temperature field control component and a non-contact laser displacement measurement array component; a honeycomb layer is arranged inside the furnace body; the distributed temperature field control component includes a group of infrared radiation heaters; the non-contact laser displacement measurement array component includes a group of laser sensors; the steel tube concrete specimen is uniformly heated by the distributed temperature field control component, the honeycomb layer can provide installation points and structural protection for the infrared radiation heaters and thermocouples, thereby improving radiation uniformity and thermal efficiency, and the deformation of various parts of the steel tube concrete specimen is measured by the non-contact laser displacement measurement array component to avoid direct contact between the sensor and the steel tube concrete specimen.

Description

Technical Field

[0001] The present invention belongs to the technical field of combined structure testing, in particular to a high-precision measurement method and equipment for the fire resistance of a high-strength steel tube concrete structure. Background Art

[0002] As a new type of composite structure, concrete-filled steel tube (CFST) structures are widely used in modern buildings, bridges, steel structures, and other projects. They possess excellent mechanical properties, such as high compressive, flexural, and shear strength. Furthermore, the steel tube shell effectively protects the concrete from environmental influences, extending the service life of the structure. However, with increasingly stringent building safety standards, the fire resistance of CFST structures is receiving increasing attention.

[0003] The fire behavior of concrete-filled steel tube (CFST) structures exhibits complex characteristics under fire conditions. The steel tube expands and loses strength under high temperatures, while the concrete cracks, expands, and decomposes under high temperatures, seriously affecting the stability of the structure. While some research has focused on the fire resistance of CFST structures, there is currently a lack of efficient, accurate, and repeatable testing equipment to evaluate the fire resistance of these structures.

[0004] The temperature fields in different areas of the existing steel tube concrete structure fire resistance performance measurement equipment vary greatly, usually greater than 15°C. The heating effect on the steel tube concrete is not uniform, and local locations may not be heated to the expected temperature, which can easily affect the measurement accuracy. In addition, traditional deformation measurement technology relies on contact sensors. The setting of the sensor will reversely apply load or restraint effects to the steel tube concrete specimen, affecting the stress state of the steel tube concrete specimen and ultimately leading to deviations in the measurement results.

[0005] To this end, the present invention provides a high-precision measurement method and equipment for the fire resistance of high-strength steel tube concrete structures. Summary of the Invention

[0006] In order to make up for the deficiencies of the prior art, at least one technical problem raised in the background technology is solved.

[0007] The technical solution adopted by the present invention to solve the technical problem is as follows: the high-precision measurement equipment for fire resistance of high-strength steel tube concrete structure of the present invention includes a data acquisition and calculation platform and a heating furnace;

[0008] The heating furnace is used to heat the steel tube concrete specimen and measure its deformation; the heating furnace includes a furnace body, a distributed temperature field control component and a non-contact laser displacement measurement array component;

[0009] The furnace body is provided with a movable door and a fixed door at both ends; a honeycomb layer is provided inside the furnace body; a group of holes are evenly distributed on the surface of the honeycomb layer; the honeycomb layer is built with honeycomb refractory bricks;

[0010] The distributed temperature field control assembly includes a set of infrared radiation heaters evenly distributed in the honeycomb layer; the infrared radiation heaters are fixedly installed inside the holes; the infrared radiation heaters are divided into five independent temperature control zones along the axis of the steel tube concrete specimen;

[0011] The non-contact laser displacement measurement array assembly includes a group of laser sensors evenly distributed on the furnace body; the laser sensors measure the local laser displacement signal of the steel tube concrete specimen through blank holes;

[0012] The data acquisition and computing platform is used to collect laser displacement signals and calculate the deformation of steel tube concrete specimens; the data acquisition and computing platform includes an ADC module and an edge computing unit.

[0013] Preferably, a group of measuring chambers are evenly distributed on the surface of the furnace body, and the measuring chambers are coaxially arranged with the blank holes at corresponding positions of the honeycomb layer; a quartz glass plate is fixedly connected to the inside of the measuring chamber; the laser sensors are all fixedly installed on the surface of the measuring chamber, and the detection end of the laser sensor is located inside the measuring chamber.

[0014] Preferably, a central column is provided inside the furnace body, and the central column is fixedly connected to the fixed door; a group of rollers are evenly distributed on the surface of the central column.

[0015] Preferably, a group of grooves are evenly distributed on the outside of the central column; a core shaft is fixedly connected to the inside of the groove, and a roller is sleeved on the outside of the core shaft; the roller can rotate and slide laterally on the surface of the core shaft.

[0016] Preferably, a water channel is opened inside the central column; a group of cooling holes are distributed between the water channel and the surface of the central column; and the water channel is connected to an external water source through a water pipe.

[0017] Preferably, a blocking assembly is provided on the inner side of the movable door and the fixed door; the blocking assembly includes a retaining ring and an operating rod; a group of springs are arranged between the retaining ring and the movable door or the fixed door; the operating rod is rotatably connected to the retaining ring; the operating rod passes through the movable door or the fixed door and is connected to it through a screw nut pair; a drain pipe is provided at the bottom of one of the retaining rings.

[0018] Preferably, a group of diversion bins are evenly distributed at the bottom of the center column; a hollow elastic block is fixedly connected inside the diversion bin; an elastic part is fixedly connected inside the elastic block; a water inlet is connected to the bottom of the elastic block; a water riser is connected to the side of the elastic block; the water riser is designed to be annular and is located outside the center column; a group of guide holes are evenly distributed on the top of the water riser; a one-way valve is provided inside the water inlet and the water riser.

[0019] Preferably, a chute is provided between the water channel and the diversion chamber; a rotating shaft is rotatably connected inside the water channel, and the rotation of the rotating shaft is controlled by a motor; a group of crankshafts are evenly distributed on the surface of the rotating shaft; a slider is slidably connected inside the chute; a connecting rod is provided between the slider and the crankshaft; the lower end of the connecting rod is hinged to the slider, and the upper end of the connecting rod is rotatably connected to the crankshaft.

[0020] A high-precision measurement method for the fire resistance of a high-strength steel tube concrete structure, using the above-mentioned high-precision measurement equipment, comprises the following steps:

[0021] S1. Pour C50 concrete inside the steel tube to form a ring-shaped concrete-filled steel tube specimen. Hoist the concrete-filled steel tube specimen into the furnace body and sleeve it on the surface of the central column. Close the movable door.

[0022] S2. Heat the concrete-filled steel tube specimen using a distributed temperature field control component at a heating rate of 13.5°C / min until the temperature reaches 1000°C.

[0023] S3. Deformation measurements are performed on various parts of the concrete-filled steel tube specimen using a non-contact laser displacement measurement array assembly. The edge computing unit then calculates the specific values ​​of the bulging deformation and mid-span deflection.

[0024] S4. After the test is completed, the retaining rings on both sides are controlled to move closer to the CFST specimen and seal the gap between the CFST specimen and the central column, so that an annular cavity is formed between the central column, the CFST specimen, and the retaining rings;

[0025] S5. Cooling water is introduced into the water channel through the water pipe, and then the water flows out from the surface of the central column along the multiple cooling holes and sprays on the surface of the steel tube concrete specimen to cool the steel tube concrete specimen;

[0026] S6. The motor drives the rotating shaft and the crankshaft to control the slider to move up and down inside the slide. The slider intermittently squeezes the elastic block to continuously guide the water gathered at the bottom of the annular cavity upward and spray it onto the top surface of the steel tube concrete specimen.

[0027] The beneficial effects of the present invention are as follows:

[0028] 1. The high-precision measurement method and equipment for the fire resistance of high-strength concrete-filled steel tube structures described in the present invention uniformly heat the concrete-filled steel tube specimen through a distributed temperature field control component. The honeycomb layer not only provides installation points and structural protection for infrared radiation heaters and thermocouples, but also improves radiation uniformity and thermal efficiency. A non-contact laser displacement measurement array component is used to measure deformation of various parts of the concrete-filled steel tube specimen. The edge computing unit then calculates the specific values ​​of the bulging deformation and mid-span deflection, avoiding direct contact between the sensor and the concrete-filled steel tube specimen, preventing any restrictions on the stress state of the concrete-filled steel tube specimen, and improving the measurement accuracy of the fire resistance of the concrete-filled steel tube.

[0029] 2. In the high-precision measurement method and equipment for the fire resistance of high-strength concrete-filled steel tube structures described in the present invention, the optical path of the laser sensor can pass through the quartz glass plate and holes, thereby completing the measurement of the concrete-filled steel tube specimen. By mounting the laser sensor on the surface of the measurement chamber, the honeycomb layer is prevented from contacting and transferring heat to the sensor, preventing overheating and damage to the laser sensor, thereby improving the protection of the sensor.

[0030] 3. The high-precision measurement method and equipment for the fire resistance of high-strength steel tube concrete structures described in the present invention, by setting a central column, the annular steel tube concrete specimen is sleeved on the surface of the central column, thereby improving the coincidence of the honeycomb layer and the axis of the steel tube concrete specimen, ensuring the heating uniformity and measurement accuracy of the steel tube concrete specimen, and the roller on the surface of the central column is conducive to the installation and disassembly of the steel tube concrete specimen. During the test, the steel tube concrete specimen can be deformed and moved along the axial direction on the surface of the central column, reducing the friction resistance between the steel tube concrete specimen and the central column, further reducing the restraint effect on the steel tube concrete specimen, and preventing friction resistance from affecting the stress state of the steel tube concrete specimen. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention will be further described below with reference to the accompanying drawings.

[0032] Figure 1 It is a three-dimensional diagram of the furnace body of the present invention;

[0033] Figure 2 is a cross-sectional view of the furnace body of the present invention;

[0034] Figure 3 yes Figure 2 A partial enlarged view of the middle part;

[0035] Figure 4 yes Figure 2 A partial enlarged view of point B in the middle;

[0036] Figure 5 yes Figure 2 Cross-sectional view at CC;

[0037] Figure 6 yes Figure 5 A partial enlarged view of point D in the middle;

[0038] Figure 7 It is a structural schematic diagram of the central column in the present invention;

[0039] Figure 8 yes Figure 7 A partial enlarged view of point E in the middle;

[0040] Figure 9 It is a structural schematic diagram of the water riser in the present invention;

[0041] Figure 10 It is a flow chart of the measurement method of the present invention.

[0042] In the figure: concrete-filled steel tube specimen 1, furnace body 2, movable door 3, fixed door 4, honeycomb layer 5, hole 6, laser sensor 7, measuring chamber 8, quartz glass plate 9, center column 10, roller 11, groove 12, core shaft 13, water channel 14, cooling hole 15, water pipe 16, retaining ring 17, operating rod 18, spring 19, drain pipe 20, diversion chamber 21, elastic block 22, elastic member 23, water inlet 24, water riser 25, guide hole 26, chute 27, rotating shaft 28, motor 29, crankshaft 30, slider 31, connecting rod 32. DETAILED DESCRIPTION

[0043] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0044] like Figures 1 to 9 As shown, the high-precision measurement equipment for fire resistance of high-strength steel tube concrete structure of the present invention includes a data acquisition and calculation platform and a heating furnace;

[0045] The heating furnace is used to heat the steel tube concrete specimen 1 and measure its deformation; the heating furnace includes a furnace body 2, a distributed temperature field control component and a non-contact laser displacement measurement array component;

[0046] The furnace body 2 is provided with a movable door 3 and a fixed door 4 at both ends; the top of the movable door 3 is rotatably connected to the furnace body 2; a honeycomb layer 5 is provided inside the furnace body 2; a group of holes 6 are uniformly distributed on the surface of the honeycomb layer 5; the honeycomb layer 5 is made of honeycomb refractory bricks;

[0047] The distributed temperature field control assembly includes a set of infrared radiation heaters evenly distributed throughout the honeycomb layer 5; each of the infrared radiation heaters is fixedly mounted within the holes 6; the infrared radiation heaters are divided into five independent temperature control zones along the axis of the concrete-filled steel tube specimen 1, with a temperature deviation of ≤±3°C; infrared radiation heaters are staggered within only 25% of the holes 6, i.e., one heating point is located within every four holes, while the remaining holes 6 remain open; thermocouples may also be installed within the remaining blank holes 6, with the gaps between the thermocouples and the hole walls filled with alumina fiber cotton for real-time temperature monitoring of each independent temperature control zone;

[0048] The non-contact laser displacement measurement array assembly includes a group of laser sensors 7 uniformly distributed on the furnace body 2; the laser sensors 7 measure the local laser displacement signal of the steel tube concrete specimen 1 through the blank hole 6; the laser sensors 7 are arranged in 8 groups along the axis of the steel tube concrete specimen 1, with 4 laser sensors arranged in each group in a circumferential direction;

[0049] The data acquisition and calculation platform is used to collect laser displacement signals and calculate the deformation of the steel tube concrete specimen 1; the data acquisition and calculation platform includes an ADC module and an edge computing unit.

[0050] The temperature fields in different areas of the steel tube concrete structure fire resistance performance measurement equipment in the existing technology vary greatly, usually greater than 15°C. The heating effect on the steel tube concrete is not uniform enough, and local positions may not be heated to the expected temperature, which can easily affect the measurement accuracy. In addition, traditional deformation measurement technology relies on contact sensors. The setting of the sensor will reversely apply load or restraint effect to the steel tube concrete specimen 1, affecting the stress state of the steel tube concrete specimen 1, and ultimately leading to deviations in the measurement results.

[0051] The present invention uniformly heats the steel tube concrete specimen 1 through a distributed temperature field control component. The honeycomb layer 5 can provide installation points and structural protection for the infrared radiation heater and the thermocouple on the one hand. On the other hand, the honeycomb structure can improve the radiation uniformity and thermal efficiency. The deformation of each part of the steel tube concrete specimen 1 is measured by a non-contact laser displacement measurement array component, and the specific values ​​of the bulging deformation and mid-span deflection are calculated by the edge computing unit, avoiding direct contact between the sensor and the steel tube concrete specimen 1, preventing restrictions on the stress state of the steel tube concrete specimen 1, and improving the measurement accuracy of the fire resistance of the steel tube concrete.

[0052] A set of measuring chambers 8 are uniformly distributed across the surface of the furnace body 2, coaxially arranged with the blank holes 6 at corresponding locations on the honeycomb layer 5. Each measuring chamber 8 corresponds to a blank hole 6 not equipped with an infrared radiation heater. The measuring chamber 8 is located outside and connected to the blank hole 6, with their axes coinciding. A quartz glass plate 9 is fixedly attached to the interior of each measuring chamber 8. Each laser sensor 7 is fixedly mounted on the surface of the measuring chamber 8, with its detection end located within the chamber. The optical path of the laser sensor 7 can pass through the quartz glass plate 9 and the hole 6, thereby completing the measurement of the concrete-filled steel tube specimen 1. By mounting the laser sensor 7 on the surface of the measuring chamber 8, contact and heat transfer between the honeycomb layer 5 and the sensor are prevented, preventing overheating and damage to the laser sensor 7, thereby enhancing sensor protection.

[0053] As another embodiment of the present invention, a central column 10 is provided within the furnace body 2 and is fixedly connected to the fixed door 4. A set of rollers 11 are evenly distributed on the surface of the central column 10. By providing the central column 10, the annular concrete-filled steel tube specimen 1 is sleeved onto the surface of the central column 10, thereby improving the overlap between the honeycomb layer 5 and the axis of the concrete-filled steel tube specimen 1, ensuring heating uniformity and measurement accuracy of the concrete-filled steel tube specimen 1. The rollers 11 on the surface of the central column 10 facilitate installation and removal of the concrete-filled steel tube specimen 1. During testing, the concrete-filled steel tube specimen 1 can deform and move along the axis of the central column 10, reducing frictional resistance between the concrete-filled steel tube specimen 1 and the central column 10, further reducing the restraining effect on the concrete-filled steel tube specimen 1, and preventing frictional resistance from affecting the stress state of the concrete-filled steel tube specimen 1.

[0054] A set of grooves 12 are evenly distributed on the outside of the central column 10. A core shaft 13 is fixedly connected to the grooves 12, and a roller 11 is mounted on the outside of the core shaft 13. The roller 11 can rotate and slide laterally on the surface of the core shaft 13. While the roller 11 can rotate around the core shaft 13, it can also move tangentially within the grooves 12 along the central column 10, thereby further accommodating the lateral deformation and movement of the steel tube concrete specimen 1, ensuring its free deformation and maximally restoring its deformed state after heating.

[0055] As another embodiment of the present invention, a water channel 14 is provided within the center column 10; a group of cooling holes 15 are uniformly distributed between the water channel 14 and the surface of the center column 10; and the water channel 14 is connected to an external water source via a water pipe 16. After the test is completed, cooling water is introduced into the water channel 14 through the water pipe 16. The water then flows outward from the surface of the center column 10 through the multiple cooling holes 15 and sprays onto the surface of the steel tube concrete specimen 1, thereby rapidly cooling the steel tube concrete specimen 1, preventing burns to personnel during the disassembly and subsequent handling of the steel tube concrete specimen 1, and reducing safety risks.

[0056] The movable door 3 and the fixed door 4 are both provided with a blocking assembly on the inner side; the blocking assembly includes a retaining ring 17 and an operating rod 18; a group of springs 19 are evenly distributed between the retaining ring 17 and the movable door 3 or the fixed door 4; the operating rod 18 is rotatably connected to the retaining ring 17; the operating rod 18 passes through the movable door 3 or the fixed door 4 and is connected to it through a screw nut pair; a drain pipe 20 is provided at the bottom of one of the retaining rings 17. By rotating the operating lever 18, the retaining rings 17 on both sides are controlled to approach the steel tube concrete specimen 1, and then the retaining rings 17 are sleeved on the surface of the central column 10 and abut against the end face of the steel tube concrete specimen 1, thereby sealing the gap between the steel tube concrete specimen 1 and the central column 10, so that a relatively sealed annular cavity is formed between the central column 10, the steel tube concrete specimen 1 and the retaining rings 17, and then cooling water is introduced into the annular cavity for cooling, which can prevent a large amount of water from overflowing into the interior of the equipment. After the water in the annular cavity cools the steel tube concrete specimen 1, the formed water vapor and high-temperature water are discharged outward through the drain pipe 20.

[0057] As another embodiment of the present invention, a group of diversion bins 21 are evenly distributed at the bottom of the central column 10; a hollow elastic block 22 is fixedly connected inside the diversion bin 21; an elastic member 23 is fixedly connected inside the elastic block 22; a water inlet 24 is connected to the bottom of the elastic block 22; a water riser 25 is connected to the side of the elastic block 22; the water riser 25 is designed to be annular and is located outside the central column 10; a group of guide holes 26 are evenly distributed on the top of the water riser 25; and a one-way valve is provided inside the water inlet 24 and the water riser 25.

[0058] A chute 27 is provided between the water channel 14 and the diversion chamber 21; a rotating shaft 28 is rotatably connected inside the water channel 14, and the rotation of the rotating shaft 28 is controlled by a motor 29; a group of crankshafts 30 are evenly distributed on the surface of the rotating shaft 28; a slider 31 is slidably connected inside the chute 27; a connecting rod 32 is provided between the slider 31 and the crankshaft 30; the lower end of the connecting rod 32 is hinged to the slider 31, and the upper end of the connecting rod 32 is rotatably connected to the crankshaft 30.

[0059] During the cooling process, after the water flows through the cooling holes 15 and is sprayed onto the surface of the steel tube concrete specimen 1, it will gradually converge downward to the bottom of the annular cavity under the action of gravity, resulting in a better cooling effect at the bottom of the steel tube concrete specimen 1 than at the top. Therefore, the motor 29 drives the rotating shaft 28 and the multiple crankshafts 30 to rotate, and the periodic swing of the crankshaft 30 is utilized to drive the slider 31 to reciprocate up and down inside the chute 27 through the connecting rod 32. When the slider 31 moves downward, it can squeeze the elastic block 22. The water inside the elastic block 22 is pressed and enters the water riser 25, prompting the water to It flows back upward along the riser pipe 25 and is sprayed out through the guide hole 26 at the top of the riser pipe 25. When the slider 31 moves upward, the elastic block 22 expands and recovers under the action of its own elastic force and the elastic member 23, and negative pressure is generated inside it. The water at the bottom of the steel tube concrete specimen 1 is sucked into the elastic block 22 through the water inlet 24, forming a circulating flow. This structure utilizes the elastic block 22 and the one-way valve to continuously guide the water gathered at the bottom of the annular cavity upward and spray it onto the top surface of the steel tube concrete specimen 1, thereby further improving the cooling uniformity of the steel tube concrete specimen 1.

[0060] like Figure 10 As shown, the high-precision measurement method for the fire resistance of high-strength steel tube concrete structure of the present invention adopts the above-mentioned high-precision measurement equipment and includes the following steps:

[0061] S1. Pour C50 concrete inside a steel tube (wall thickness 8-20 mm) to form a ring-shaped concrete-filled steel tube specimen 1. Hoist the concrete-filled steel tube specimen 1 into the furnace body 2 and sleeve it onto the surface of the central column 10. Close the movable door 3.

[0062] S2. Heating the steel tube concrete specimen 1 by using the distributed temperature field control component at a heating rate of 13.5°C / min until the temperature reaches 1000°C;

[0063] S3. Deformation measurement is performed on various parts of the steel tube concrete specimen 1 using a non-contact laser displacement measurement array assembly, and the specific values ​​of the bulging deformation and mid-span deflection are calculated by the edge computing unit;

[0064] S4. After the test is completed, the retaining rings 17 on both sides are controlled to move closer to the CFST specimen 1 and to seal the gap between the CFST specimen 1 and the central column 10, so that an annular cavity is formed between the central column 10, the CFST specimen 1, and the retaining rings 17;

[0065] S5. Cooling water is introduced into the water channel 14 through the water pipe 16. The water then flows outward from the surface of the central column 10 along the multiple cooling holes 15 and sprays onto the surface of the steel tube concrete specimen 1 to cool the steel tube concrete specimen 1.

[0066] S6. The motor 29 drives the rotating shaft 28 and the crankshaft 30 to control the slider 31 to reciprocate up and down inside the slide 27. The slider 31 intermittently squeezes the elastic block 22 to continuously guide the water gathered at the bottom of the annular cavity upward and spray it onto the top surface of the steel tube concrete specimen 1.

[0067] The above-mentioned front, back, left, right, up and down are all based on the Figure 1 As a benchmark, according to the person's observation perspective, the side of the device facing the observer is defined as the front, the left side of the observer is defined as the left, and so on.

[0068] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present invention.

[0069] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. High-precision measurement equipment for the fire resistance of high-strength concrete-filled steel tube structures, including a data acquisition and calculation platform and a heating furnace; Its characteristics are: The heating furnace is used to heat a steel tube concrete test piece (1) and measure its deformation; the heating furnace comprises a furnace body (2), a distributed temperature field control component, and a non-contact laser displacement measurement array component; The furnace body (2) is provided with a movable door (3) and a fixed door (4) at both ends; a honeycomb layer (5) is provided inside the furnace body (2); a group of holes (6) are evenly distributed on the surface of the honeycomb layer (5); the honeycomb layer (5) is built with honeycomb refractory bricks; The distributed temperature field control component includes a group of infrared radiation heaters uniformly distributed in the honeycomb layer (5); the infrared radiation heaters are fixedly installed inside the hole (6); the infrared radiation heaters are divided into five independent temperature control zones along the axis direction of the steel tube concrete specimen (1); The non-contact laser displacement measurement array assembly comprises a group of laser sensors (7) uniformly distributed on the furnace body (2); the laser sensors (7) measure local laser displacement signals of the steel tube concrete specimen (1) through blank holes (6); The data acquisition and calculation platform is used to collect laser displacement signals and calculate the deformation of the steel tube concrete specimen (1); the data acquisition and calculation platform includes an ADC module and an edge computing unit; A group of measuring chambers (8) are uniformly distributed on the surface of the furnace body (2), and the measuring chambers (8) are coaxially arranged with the blank holes (6) at corresponding positions of the honeycomb layer (5); a quartz glass plate (9) is fixedly connected inside the measuring chamber (8); the laser sensors (7) are fixedly installed on the surface of the measuring chamber (8), and the detection end of the laser sensor (7) is located inside the measuring chamber (8); A central column (10) is provided inside the furnace body (2), and the central column (10) is fixedly connected to the fixed door (4); a group of rollers (11) are evenly distributed on the surface of the central column (10); A group of grooves (12) are evenly distributed on the outside of the central column (10); a core shaft (13) is fixedly connected inside the groove (12), and the roller (11) is sleeved on the outside of the core shaft (13); the roller (11) can rotate and slide laterally on the surface of the core shaft (13); A water channel (14) is provided inside the central column (10); a group of cooling holes (15) are evenly distributed between the water channel (14) and the surface of the central column (10); and the water channel (14) is connected to an external water source through a water pipe (16).

2. The high-precision measurement equipment for fire resistance of high-strength concrete-filled steel tube structures according to claim 1 is characterized by: The movable door (3) and the fixed door (4) are both provided with a blocking assembly on their inner sides; the blocking assembly comprises a retaining ring (17) and an operating rod (18); a group of springs (19) are arranged between the retaining ring (17) and the movable door (3) or the fixed door (4); the operating rod (18) is rotatably connected to the retaining ring (17); the operating rod (18) passes through the movable door (3) or the fixed door (4) and is connected thereto via a screw-nut pair; a drain pipe (20) is provided at the bottom of one of the retaining rings (17).

3. The high-precision measurement equipment for fire resistance of high-strength concrete-filled steel tube structures according to claim 2 is characterized by: A group of diversion chambers (21) are evenly distributed at the bottom of the central column (10); a hollow elastic block (22) is fixedly connected inside the diversion chamber (21); an elastic member (23) is fixedly connected inside the elastic block (22); a water inlet (24) is connected to the bottom of the elastic block (22); a water riser (25) is connected to the side of the elastic block (22); the water riser (25) is designed to be annular and is located outside the central column (10); a group of guide holes (26) are evenly distributed on the top of the water riser (25); and a one-way valve is provided inside the water inlet (24) and the water riser (25).

4. The high-precision measurement equipment for fire resistance of high-strength concrete-filled steel tube structures according to claim 3 is characterized by: A chute (27) is provided between the water channel (14) and the diversion chamber (21); a rotating shaft (28) is rotatably connected inside the water channel (14), and the rotating shaft (28) is controlled to rotate by a motor (29); a group of crankshafts (30) are evenly distributed on the surface of the rotating shaft (28); a slider (31) is slidably connected inside the chute (27); a connecting rod (32) is provided between the slider (31) and the crankshaft (30); the lower end of the connecting rod (32) is hinged to the slider (31), and the upper end of the connecting rod (32) is rotatably connected to the crankshaft (30).

5. A high-precision measurement method for the fire resistance of high-strength concrete-filled steel tube structures, the method using the high-precision measurement equipment according to claim 4, characterized in that: The following steps are involved: S1. Pour C50 concrete inside the steel tube to form a ring-shaped steel tube concrete specimen (1). Hoist the steel tube concrete specimen (1) into the furnace body (2) and sleeve it on the surface of the central column (10). Close the movable door (3). S2, heating the steel tube concrete specimen (1) by using a distributed temperature field control component, controlling the heating rate to be 13.5°C / min; until the temperature reaches 1000°C; S3. The deformation of each part of the steel tube concrete specimen (1) is measured by a non-contact laser displacement measurement array component, and the specific values ​​of the bulging deformation and mid-span deflection are calculated by the edge computing unit.

6. The high-precision measurement method for fire resistance of high-strength concrete-filled steel tube structures according to claim 5, characterized in that: The following steps are also included: S4. After the test is completed, the retaining rings (17) on both sides are controlled to approach the steel tube concrete specimen (1) and seal the gap between the steel tube concrete specimen (1) and the central column (10), so that an annular cavity is formed between the central column (10), the steel tube concrete specimen (1), and the retaining rings (17); S5. Cooling water is introduced into the water channel (14) through the water pipe (16), and the water flows outward from the surface of the central column (10) along the plurality of cooling holes (15), and sprayed on the surface of the steel tube concrete specimen (1), thereby cooling the steel tube concrete specimen (1); S6, the motor (29) drives the rotating shaft (28) and the crankshaft (30), and controls the slider (31) to reciprocate up and down inside the slide groove (27). The slider (31) intermittently squeezes the elastic block (22), and continuously guides the water gathered at the bottom of the annular cavity upward and sprays it onto the top surface of the steel tube concrete specimen (1).

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