A test device and process for the fire resistance performance of steel-concrete composite columns

Abstract

This invention relates to the field of fire resistance testing of steel-concrete composite columns, specifically a testing device and process for the fire resistance performance of steel-concrete composite columns. The device includes a base plate, a combustion furnace located at the front center of the base plate, and a support plate positioned between the base plate and the combustion furnace. The bottom of the support plate is slidably connected to a T-shaped groove in the base plate. Hydraulic struts are symmetrically arranged above the support plate, with a fixed outer frame connected to the upper end of each strut on the same side. A clamping assembly is located in the middle of the fixed outer frame, and a distance measuring assembly is located at the top of the fixed outer frame. A central control module is located at the top of the support plate. This invention uses the clamping assembly to horizontally clamp the steel-concrete composite column. A rotating disk, driven by a servo motor, allows the steel-concrete composite column to rotate in different ways, enabling single-sided or multi-sided heating of the column in the combustion furnace. This simulates fires under different conditions and prevents uneven heating of the steel-concrete composite column in the combustion furnace from causing errors in the experimental data.

Description

Technical Field

[0001] This invention relates to the field of fire resistance testing of concrete-filled steel tube columns, specifically to a testing device and process for the fire resistance performance of concrete-filled steel tube columns. Background Technology

[0002] Concrete-tube steel (CT) columns are structural members formed by filling concrete into a steel tube, where the steel tube and the core concrete work together to withstand external loads. Based on their cross-sectional shape, they can be classified as circular CT columns, square / rectangular CT columns, and polygonal CT columns. In recent years, CT structures have been increasingly used in industrial and civil buildings. However, due to the high temperatures involved in fire resistance testing of CT columns, the placement of strain gauges is significantly limited. Therefore, the equipment for testing the fire resistance of CT columns remains immature, leading to substantial losses in fires involving buildings using CT columns. Thus, there is an urgent need to upgrade the equipment for testing the fire resistance of CT columns.

[0003] Utility model patent CN208171761U discloses a high-temperature loading test device for steel-concrete composite columns. This patent uses a laser rangefinder to test the deformation and displacement values ​​of the steel-concrete composite column outside a fire test furnace, effectively avoiding direct exposure of the loading test device to high temperatures. The measured displacement values ​​can be conveniently used to calculate the stress value at which the steel-concrete composite column fails at high temperatures. However, this patent still has the following problems when testing the fire resistance performance of steel-concrete composite columns: 1. Because the heating point and the steel-concrete composite column are fixed in the fire test furnace of the above scheme, the heating of the steel-concrete composite column is not uniform, and... The experiment needs to simulate more fire scenarios. For example, scenarios where only half of a circular steel-concrete composite column located at the corner of a building is heated, or where several sides of a polygonal concrete column are heated, cannot be simulated, which has limitations. In addition, the above method of locking steel-concrete composite columns with different structures is unstable. 2. When the fire test furnace with eight evenly distributed nozzles on each side is used to simulate fire on conical steel-concrete composite columns, the distance between the two ends of the conical steel-concrete composite column and the nozzles will be different, resulting in uneven heating at both ends of the conical steel-concrete composite column, which leads to large errors in the experimental data. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a fire resistance performance testing device for steel tube concrete columns, including a base plate, a combustion furnace is arranged on the front side of the middle part of the base plate, a support plate is arranged between the base plate and the lower side of the combustion furnace, T-shaped grooves are symmetrically arranged on the left and right sides of the base plate, the bottom of the support plate is slidably connected in the T-shaped grooves, hydraulic struts are symmetrically arranged on the left and right sides of the upper part of the support plate by hinge, the upper end of the hydraulic strut on the left is connected to a fixed outer frame, the upper end of the hydraulic strut on the right is connected to a fixed outer frame by hinge, a clamping component is arranged in the middle of the fixed outer frame, a distance measuring component is arranged on the upper part of the fixed outer frame, and a central control module is arranged on the upper part of the support plate.

[0005] The clamping assembly includes a rotating disk rotatably mounted through the middle of a fixed outer frame. The outer circumference of the rotating disk near the combustion furnace has gear teeth. A servo motor is mounted on the side of the fixed outer frame away from the combustion furnace. The output shaft of the servo motor passes through the fixed outer frame, and a drive gear meshes with the gear teeth on the outer surface of the rotating disk on the output shaft. Multiple through-slots are evenly distributed around the circumference of the rotating disk. Sliding blocks are slidably mounted within these slots, passing through both sides of the rotating disk. A fixed block is hinged to one end of each sliding block near the combustion furnace, and the other end of each sliding block is hinged to one end of a connecting rod. An adjusting screw is rotatably mounted in the middle of the side of the rotating disk away from the combustion furnace, and a moving block is fitted onto the adjusting screw. The other end of the connecting rod is hinged to the side of the moving block. A hydraulic push rod is embedded in the middle of the side of the rotating disk near the combustion furnace, and a pressure plate is mounted on the telescopic end of the hydraulic push rod. A pressure detector is installed within the pressure plate.

[0006] The ranging component includes a multi-stage cylinder fixedly mounted on the upper part of the fixed outer frame. A connecting block is fixedly mounted on the telescopic end of the multi-stage cylinder. An installation block is mounted on the side of the connecting block near the combustion furnace by means of a hinge. A downward probe cylinder is mounted on the lower side of the installation block. A rangefinder is connected to the telescopic end of the downward probe cylinder.

[0007] As a preferred embodiment of the present invention, the connecting block and the mounting block are hinged together by a positioning shaft that passes through them, and both the connecting block and the mounting block are provided with insertion holes for the positioning shaft to pass through.

[0008] As a preferred embodiment of the present invention, the positioning shaft has multiple protrusions evenly arranged circumferentially at the position of the mounting block insertion hole. One end of the positioning shaft is provided with a hexagonal protrusion, and the other end of the positioning shaft is provided with a thread and a nut is provided to cooperate with it. The insertion hole of the connecting block for the positioning shaft to pass through is larger in diameter than the insertion hole of the mounting block for the positioning shaft to pass through. The insertion hole of the mounting block for the positioning shaft to pass through has multiple grooves evenly arranged circumferentially for the protrusions of the positioning shaft to pass through and be positioned.

[0009] As a preferred embodiment of the present invention, the fixing block is a cubic structure, and an arc-shaped groove is provided in the middle of the side of the block closest to the axis of the rotating disk.

[0010] As a preferred embodiment of the present invention, a threaded plate is provided on the side of the fixed outer frame away from the combustion furnace, and a positioning rod is inserted into the threaded plate. The diameter of the positioning rod is smaller than the diameter of the threaded hole in the middle of the threaded plate. The middle of the positioning rod is provided with an external thread that matches the threaded hole in the middle of the threaded plate. A hole is provided on the upper surface of the support plate corresponding to the position of the positioning rod for the lower end of the positioning rod to pass through.

[0011] As a preferred embodiment of the present invention, the rear side of the combustion furnace is open, and a baffle is provided on the rear side of the combustion furnace, which is engaged with the opening of the combustion furnace. The baffle is connected to the combustion furnace by bolts.

[0012] As a preferred embodiment of the present invention, the central control module includes a central control unit, which is electrically connected to a cylinder control unit, a hydraulic cylinder control unit, a motor control unit, and a data acquisition unit. The cylinder control unit is electrically connected to a multi-stage cylinder and a downward-protruding cylinder. The hydraulic cylinder control unit is electrically connected to a hydraulic strut and a hydraulic push rod. The motor control unit is electrically connected to a servo motor. The data acquisition unit is electrically connected to a rangefinder and a pressure detector.

[0013] In addition, the present invention also provides a test process for the fire resistance performance of steel-concrete composite columns, the specific steps of which are as follows: S1, clamping and installation: the rotating adjusting screw drives multiple fixed blocks to move outward of the rotating disk through the moving block, and the steel-concrete composite column is placed between the fixed blocks by hoisting. The rotating adjusting screw drives multiple fixed blocks to move inward of the rotating disk through the moving block, so that the fixed blocks clamp the steel-concrete composite column.

[0014] S2. Rotary heating: The middle part of the steel-concrete composite column is placed in the combustion furnace for heating. The servo motor drives the rotating disk to rotate, which in turn drives the steel-concrete composite column to rotate, so that the combustion furnace heats the surface of the steel-concrete composite column evenly. At the same time, the extension end of the hydraulic push rod is controlled to extend and apply a certain pressure to the axial direction of the steel-concrete composite column. The pressure detector installed in the pressure plate obtains the pressure value.

[0015] S3. Measurement of Deformation: After the steel-concrete composite column has been heated and cooled, the support plate is moved backward manually, which moves the clamping assembly and the steel-concrete composite column out of the combustion furnace. The movement of the multi-stage cylinder and the downward cylinder is controlled to move the rangefinder on the side of the steel-concrete composite column. The rangefinder measures the length and cross-sectional dimensions of the steel-concrete composite column and records the data.

[0016] The beneficial effects of the present invention are as follows: First, the present invention uses a clamping assembly to horizontally clamp the steel-concrete composite column. The rotating disk can rotate the steel-concrete composite column under the drive of the servo motor. The motor control unit can control the servo motor to rotate in different ways, so that the steel-concrete composite column is heated on one side or multiple sides in the combustion furnace. This can meet the fire simulation under different conditions, and at the same time, it can prevent the steel-concrete composite column from being heated unevenly in the combustion furnace, which would cause errors in the experimental data.

[0017] Second, the clamping component of the present invention can stably clamp cylindrical steel tube concrete columns, square concrete columns, and square pyramidal concrete columns. After locking steel tube concrete columns of different sizes, the distance between the steel tube concrete column and the heating source can be quickly adjusted to increase the heating effect of the steel tube concrete column.

[0018] Third, the clamping assembly of the present invention is hinged with a hydraulic strut at the bottom. When conducting a heat resistance test on a tapered steel tube concrete column, after the clamping assembly clamps it, the heated surface of the column is at a certain angle to the heating surface of the combustion furnace. Through the extension and contraction of the symmetrical hydraulic struts on the left and right sides, the heated surface of the tapered steel tube concrete column can be aligned with the heating surface of the combustion furnace, preventing the uneven heat received at both ends of the tapered steel tube concrete column during heating, which could lead to a large experimental error.

[0019] Fourth, the positioning shaft used for the hinge between the connecting block and the mounting block of the present invention can adjust the angle between the two and fix the angle after adjustment, so that the rangefinder under the mounting block can always be perpendicular to the surface of the tapered steel pipe concrete column when measuring it, making the measurement data more accurate. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Figure 1 This is a schematic diagram of the structure of the present invention.

[0022] Figure 2 It is a cross-sectional view of the fixed outer frame, clamping components, and distance measuring components.

[0023] Figure 3 This is a structural diagram of the fixed outer frame and clamping components.

[0024] Figure 4 This is a schematic diagram of the ranging component.

[0025] Figure 5 This is a structural diagram of the connecting block, mounting block, and positioning shaft.

[0026] Figure 6 This is a structural diagram of the central control module.

[0027] Figure 7 This is a process flow diagram for testing the fire resistance performance of steel-concrete composite columns.

[0028] Figure 8 These are structural schematic diagrams of cylindrical steel-concrete composite columns, square concrete columns, and pyramidal concrete columns.

[0029] In the diagram: 1. Base plate; 11. T-shaped slide rail; 2. Combustion furnace; 21. Baffle; 3. Support plate; 31. Hydraulic strut; 4. Fixed outer frame; 41. Threaded plate; 42. Positioning rod; 5. Clamping assembly; 51. Rotary disk; 52. Servo motor; 53. Through slide rail; 54. Sliding block; 55. Fixed block; 56. Adjusting screw; 57. Moving block; 58. Hydraulic push rod; 581. Pressure plate; 59. Connecting rod; 6. Distance measuring assembly; 61. Multi-stage cylinder; 62. Connecting block; 63. Mounting block; 64. Descending cylinder; 65. Rangefinder; 66. Positioning shaft; 7. Central control module; 71. Central control unit; 72. Cylinder control unit; 73. Hydraulic cylinder control unit; 74. Motor control unit; 75. Data acquisition unit. Detailed Implementation

[0030] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in the art or in accordance with the product manual.

[0031] See Figure 1 A fire resistance testing device for steel-concrete composite columns includes a base plate 1. A combustion furnace 2 is arranged on the front side of the middle of the base plate 1. The rear side of the combustion furnace 2 is open, and a baffle 21 is provided on the rear side of the combustion furnace 2, which is locked at the opening of the combustion furnace 2. The baffle 21 is bolted to the combustion furnace 2. A support plate 3 is arranged between the base plate 1 and the lower side of the combustion furnace 2. T-shaped grooves 11 are symmetrically arranged on the left and right sides of the base plate 1. The bottom of the support plate 3 is slidably connected in the T-shaped grooves 11. The upper left and right sides of the support plate 3 are... Hydraulic struts 31 are symmetrically arranged via hinges. The upper end of the left hydraulic strut 31 is connected to a fixed outer frame 4, and the upper end of the right hydraulic strut 31 is also connected to the fixed outer frame 4 via hinges. A clamping component 5 is provided in the middle of the fixed outer frame 4, and a distance measuring component 6 is provided at the top of the fixed outer frame 4. A central control module 7 is provided at the top of the support plate 3. This invention can clamp different types of steel-concrete composite columns, such as cylindrical steel-concrete composite columns, square concrete columns, and square pyramidal concrete columns (see appendix). Figure 8The surface of the steel-concrete tube column is heated in the combustion furnace 2 and rotated to simulate different fire environments with single-sided or multi-sided heating. Axial pressure is applied to its end face and pressure data is recorded in real time. The ranging component 6 can also measure the deformation of the side of the steel-concrete tube column after heating. In addition, the present invention can adjust the position of the heated surface of the conical steel-concrete tube column to correspond with the heating surface of the combustion furnace 2, so as to prevent the two ends of the conical steel-concrete tube column from receiving different amounts of heat, which would lead to large experimental errors. Specifically, the baffle 21 of the combustion furnace 2 can be opened so that the steel-concrete tube column can be hoisted into the combustion furnace 2 and the clamping component 5 can fix it at both ends. When it is necessary to measure the deformation after heating, the baffle 21 of the combustion furnace 2 can be opened and the support plate 3 can be moved backward to move the steel-concrete tube column out of the combustion furnace 2, so that the ranging component 6 can measure the deformation. The extension and contraction of the symmetrical hydraulic struts 31 on the left and right sides can make the heated surface of the conical steel-concrete tube column correspond with the heating surface of the combustion furnace 2.

[0032] See Figure 2 , Figure 3The clamping assembly 5 includes a rotating disk 51 rotatably disposed in the middle of the fixed outer frame 4. The outer circumference of the rotating disk 51 near the combustion furnace 2 is provided with gear teeth. A servo motor 52 is disposed on the side of the fixed outer frame 4 away from the combustion furnace 2. The output shaft of the servo motor 52 passes through the fixed outer frame 4, and a drive gear is disposed on the output shaft of the servo motor 52 that meshes with the gear teeth on the outer surface of the rotating disk 51. Multiple through-slide grooves 53 are evenly distributed around the circumference of the rotating disk 51. Sliding blocks 54 are slidably disposed within the through-slide grooves 53, passing through the left and right sides of the rotating disk 51. A fixed block 55 is hinged to one end of the rotating disk 51 near the combustion furnace 2. The fixed block 55 has a cubic structure and an arc-shaped groove in the middle of the side closest to the axis of the rotating disk 51. The other end of the sliding block 54 is hinged to one end of the connecting rod 59. An adjusting screw 56 is rotatably mounted in the middle of the side of the rotating disk 51 away from the combustion furnace 2. A moving block 57 is sleeved on the adjusting screw 56. The other end of the connecting rod 59 is hinged to the side of the moving block 57. A hydraulic push rod 58 is embedded in the middle of the side of the rotating disk 51 closest to the combustion furnace 2. A pressure plate 581 is installed at the telescopic end of the hydraulic push rod 58. The pressure plate 581 is equipped with a pressure detector. The clamping assembly 5 can clamp steel-concrete composite columns with different cross-sectional shapes and diameters, and can drive them to rotate, so that they can simulate different fire environments with single-sided or multi-sided heating in the combustion furnace 2. This ensures that the steel-concrete composite column can be heated evenly when simulating different fire scenarios. Specifically, when it is necessary to test the steel-concrete composite column, first open the baffle 21 of the combustion furnace 2, and hoist the steel-concrete composite column into the combustion furnace 2. Then, rotate the adjusting screw 56 to drive multiple fixed blocks 55 to move outward of the rotating disk 51 through the moving block 57. The steel-concrete composite column is placed between the fixed blocks 55. The rotating adjusting screw 56 drives multiple fixed blocks 55 to move inward toward the rotating disk 51 through the moving block 57, so that the fixed blocks 55 clamp and fix the steel-concrete composite column. The steel-concrete composite column is heated in the combustion furnace 2. The servo motor 52 is started and drives the rotating disk 51 to rotate, which in turn drives the steel-concrete composite column to rotate, so that the combustion furnace 2 heats the surface of the steel-concrete composite column evenly. At the same time, the telescopic end of the hydraulic push rod 58 extends and applies a certain pressure to the axial direction of the steel-concrete composite column. The pressure detector set in the pressure plate 581 acquires and records the pressure value in real time.

[0033] See Figure 2 , Figure 4 , Figure 5The ranging component 6 includes a multi-stage cylinder 61 fixedly mounted on the upper part of the fixed outer frame 4. A connecting block 62 is fixedly mounted on the telescopic end of the multi-stage cylinder 61. A mounting block 63 is hinged to the side of the connecting block 62 near the combustion furnace 2. The connecting block 62 and the mounting block 63 are hinged together by a positioning shaft 66 passing through them. Both the connecting block 62 and the mounting block 63 are provided with insertion holes for the positioning shaft 66 to pass through. The positioning shaft 66 is circumferentially evenly arranged with [missing information - likely referring to a specific type of shaft] corresponding to the insertion holes of the mounting block 63. Multiple protrusions are present. One end of the positioning shaft 66 has a hexagonal protrusion, and the other end of the positioning shaft 66 has a thread and a nut for engagement. The insertion hole of the connecting block 62 for the positioning shaft 66 to pass through is larger in diameter than the insertion hole of the mounting block 63 for the positioning shaft 66 to pass through. The insertion hole of the mounting block 63 for the positioning shaft 66 to pass through has multiple grooves evenly arranged around its circumference for the circumferential protrusions of the positioning shaft 66 to pass through and be positioned. A downward probe cylinder 64 is provided on the lower side of the mounting block 63. The telescopic end of the downward probe cylinder 64 is connected to a measuring... The distance measuring instrument 65 and the distance measuring component 6 can measure parameters such as the length and cross-section of the steel-concrete composite column. For tapered steel-concrete composite columns, the distance measuring instrument 65 below the mounting block 63 can always be perpendicular to the column's surface during measurement, resulting in more accurate data. Specifically, when measuring the steel-concrete composite column, the extension or retraction of the multi-stage cylinder 61 and the downward probing cylinder 64 can move the distance measuring instrument 65 along the outer surface of the column and measure its relevant parameters. When measuring the relevant parameters of the tapered steel-concrete composite column, since its surface forms an angle with the distance measuring instrument 65, the angle of the distance measuring instrument 65 needs to be adjusted to make it perpendicular to the surface. This can be done by rotating and loosening the nut that engages with the positioning shaft 66, pulling the positioning shaft 66 to one side to release the angle lock between the mounting block 63 and the connecting block 62, and then manually adjusting the angle of the mounting block 63 to make the distance measuring instrument 65 form a suitable angle with the steel-concrete composite column.

[0034] See Figure 6 The central control module 7 includes a central control unit 71, which is electrically connected to a cylinder control unit 72, a hydraulic cylinder control unit 73, a motor control unit 74, and a data acquisition unit 75. The cylinder control unit 72 is electrically connected to a multi-stage cylinder 61 and a downward probing cylinder 64. The hydraulic cylinder control unit 73 is electrically connected to a hydraulic strut 31 and a hydraulic push rod 58. The motor control unit 74 is electrically connected to a servo motor 52. The data acquisition unit 75 is electrically connected to a rangefinder 65 and a pressure detector.

[0035] See Figure 1 , Figure 3A threaded plate 41 is provided on the side of the fixed outer frame 4 away from the combustion furnace 2. A positioning rod 42 is inserted into the threaded plate 41. The diameter of the positioning rod 42 is smaller than the diameter of the threaded hole in the middle of the threaded plate 41. The middle of the positioning rod 42 has an external thread that mates with the threaded hole in the middle of the threaded plate 41. A hole is opened on the upper surface of the support plate 3 corresponding to the position of the positioning rod 42 for the lower end of the positioning rod 42 to pass through. The positioning rod 42 can lock the position of the fixed outer frame 4 when hoisting and clamping the steel pipe concrete column to prevent... Its movement affects the clamping accuracy, enabling the present invention to perform fire resistance tests on circular steel tube concrete columns or square concrete columns. When it is necessary to perform fire resistance tests on conical steel tube concrete columns, the positioning rod 42 is pulled upwards, and the middle part of the positioning rod 42 is tightened and locked on the threaded plate 41. Then, by adjusting the height of the hydraulic support rod 31, the side of the conical steel tube concrete column can be parallel to the heating source of the combustion furnace 2, so that the conical steel tube concrete column can be heated evenly, increasing the test effect of its heat resistance performance.

[0036] It is understood that the fire resistance performance of concrete-filled steel tube columns generally includes expansion and contraction performance and deformation performance. The expansion and contraction performance of concrete-filled steel tube columns refers to the degree of deformation during the fire resistance test, while the deformation performance refers to the degree of surface deformation after the fire resistance test is completed. In this invention, the pressure change of the pressure detector installed in the pressure plate 581 can reflect the expansion and contraction performance of the concrete-filled steel tube column during the fire resistance test. At the same time, the deformation performance can be reflected by the side monitoring of the concrete-filled steel tube column by the rangefinder 65.

[0037] See Figure 7 In addition, the present invention also provides a test process for the fire resistance performance of steel-concrete composite columns, the specific steps of which are as follows: S1, clamping and installation: first, open the baffle 21 of the combustion furnace 2, then rotate the adjusting screw 56 to drive multiple fixed blocks 55 to move outward of the rotating disk 51 through the moving block 57, and place the steel-concrete composite column between the fixed blocks 55 by hoisting. Rotate the adjusting screw 56 to drive multiple fixed blocks 55 to move inward of the rotating disk 51 through the moving block 57, so that the fixed blocks 55 clamp the steel-concrete composite column. Then, install the baffle 21 of the combustion furnace 2 back on the rear side of the combustion furnace 2.

[0038] S2. Rotary heating: The steel-concrete composite column is heated in the combustion furnace 2. The central control unit 71 sends a signal to the motor control unit 74 to start the servo motor 52 and drive the rotating disk 51 to rotate, thereby driving the steel-concrete composite column to rotate, so that the combustion furnace 2 heats the surface of the steel-concrete composite column evenly. At the same time, the hydraulic cylinder control unit 73 sends a command to the hydraulic push rod 58 to extend the telescopic end of the hydraulic push rod 58 and apply a certain pressure to the axial direction of the steel-concrete composite column. The data acquisition unit 75 obtains the pressure value in real time from the pressure detector set in the pressure plate 581.

[0039] S3. Measurement of Deformation: After the steel-concrete composite column has been heated and cooled, the support plate 3 is moved backward manually, which moves the clamping assembly 5 and the steel-concrete composite column out of the combustion furnace 2. The cylinder control unit 72 issues a command to control the multi-stage cylinder 61 and the downward cylinder 64 to make the rangefinder 65 move on the side of the steel-concrete composite column. The rangefinder 65 measures the length and cross-sectional dimensions of the steel-concrete composite column and transmits the data to the data acquisition unit 75.

[0040] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention, which are still covered within the protection scope of the present invention.

Claims

1. A fire resistance testing device for steel-concrete composite columns, comprising a base plate, wherein a combustion furnace is disposed on the front side of the center of the base plate, characterized in that, A support plate is installed between the bottom plate and the lower side of the combustion furnace. T-shaped sliding grooves are symmetrically arranged on the left and right sides of the bottom plate. The bottom of the support plate is slidably connected in the T-shaped sliding grooves. Hydraulic struts are symmetrically arranged on the left and right sides above the support plate by hinge. The upper end of the hydraulic strut on the left is connected to a fixed outer frame, and the upper end of the hydraulic strut on the right is connected to a fixed outer frame by hinge. A clamping component is set in the middle of the fixed outer frame, a ranging component is set in the upper part of the fixed outer frame, and a central control module is set in the upper part of the support plate. The clamping assembly includes a rotating disk rotatably mounted through the middle of a fixed outer frame. The outer circumference of the rotating disk near the combustion furnace has gear teeth. A servo motor is mounted on the side of the fixed outer frame away from the combustion furnace. The output shaft of the servo motor passes through the fixed outer frame, and a drive gear meshes with the gear teeth on the outer side of the rotating disk on the output shaft. Multiple through-slots are evenly distributed around the circumference of the rotating disk. Sliding blocks are slidably mounted within the through-slots, passing through both sides of the rotating disk. A fixed block is hinged to one end of the sliding block near the combustion furnace, and the other end of the sliding block is hinged to one end of a connecting rod. An adjusting screw is rotatably mounted in the middle of the side of the rotating disk away from the combustion furnace, and a moving block is sleeved on the adjusting screw. The other end of the connecting rod is hinged to the side of the moving block. A hydraulic push rod is embedded in the middle of the side of the rotating disk near the combustion furnace, and a pressure plate is installed at the telescopic end of the hydraulic push rod. A pressure detector is installed inside the pressure plate. The fixing block has a cubic structure, and an arc-shaped groove is provided in the middle of the side closest to the axis of the rotating disk. The ranging component includes a multi-stage cylinder fixedly mounted on the upper part of the fixed outer frame. A connecting block is fixedly mounted on the telescopic end of the multi-stage cylinder. An installation block is mounted on the side of the connecting block near the combustion furnace by means of a hinge. A downward probe cylinder is mounted on the lower side of the installation block. A rangefinder is connected to the telescopic end of the downward probe cylinder.

2. The fire resistance testing equipment for steel-concrete composite columns according to claim 1, characterized in that, The connecting block and the mounting block are hinged together by a positioning shaft that passes through them, and both the connecting block and the mounting block are provided with insertion holes for the positioning shaft to pass through.

3. The fire resistance testing equipment for steel-concrete composite columns according to claim 2, characterized in that, The positioning shaft has multiple protrusions evenly arranged around the circumference of the corresponding mounting block insertion hole. One end of the positioning shaft is provided with a hexagonal protrusion, and the other end of the positioning shaft is provided with a thread and a nut to cooperate with it. The insertion hole of the connecting block for the positioning shaft to pass through is larger in diameter than the insertion hole of the mounting block for the positioning shaft to pass through. The insertion hole of the mounting block for the positioning shaft to pass through has multiple grooves evenly arranged around the circumference for the protrusions of the positioning shaft to pass through and be positioned.

4. The fire resistance testing equipment for steel-concrete composite columns according to claim 1, characterized in that, A threaded plate is provided on the side of the fixed outer frame away from the combustion furnace. A positioning rod is inserted through the threaded plate. The diameter of the positioning rod is smaller than the diameter of the threaded hole in the middle of the threaded plate. The middle of the positioning rod is provided with an external thread that matches the threaded hole in the middle of the threaded plate. A hole is opened on the upper surface of the support plate corresponding to the position of the positioning rod for the lower end of the positioning rod to pass through.

5. The fire resistance testing equipment for steel-concrete composite columns according to claim 1, characterized in that, The rear side of the combustion furnace is open, and a baffle is provided on the rear side of the combustion furnace, which is locked at the opening of the combustion furnace. The baffle is connected to the combustion furnace by bolts.

6. The fire resistance testing equipment for steel-concrete composite columns according to claim 1, characterized in that, The central control module includes a central control unit, which is electrically connected to the cylinder control unit, the hydraulic cylinder control unit, the motor control unit, and the data acquisition unit. The cylinder control unit is electrically connected to the multi-stage cylinder and the downward probing cylinder. The hydraulic cylinder control unit is electrically connected to the hydraulic strut and the hydraulic push rod. The motor control unit is electrically connected to the servo motor. The data acquisition unit is electrically connected to the rangefinder and the pressure detector.

7. A test process for the fire resistance performance of steel-concrete composite columns, characterized in that, The process for conducting fire resistance tests on steel-concrete composite columns using the fire resistance testing equipment described in any one of claims 1-6 is as follows: S1. Clamping and installation: The rotating adjusting screw drives multiple fixed blocks to move outwards from the rotating disk through the moving block. The steel pipe concrete column is placed between the fixed blocks by hoisting. The rotating adjusting screw drives multiple fixed blocks to move inwards from the rotating disk through the moving block, so that the fixed blocks clamp the steel pipe concrete column. S2. Rotary heating: The middle part of the steel tube concrete column is placed in the combustion furnace for heating. The servo motor drives the rotating disk to rotate, which in turn drives the steel tube concrete column to rotate, so that the combustion furnace heats the surface of the steel tube concrete column evenly. At the same time, the extension end of the hydraulic push rod is controlled to extend and apply a certain pressure to the axial direction of the steel tube concrete column. The pressure detector set in the pressure plate obtains the pressure value. S3. Measurement of Deformation: After the steel-concrete composite column has been heated and cooled, the support plate is moved backward manually, which moves the clamping assembly and the steel-concrete composite column out of the combustion furnace. The movement of the multi-stage cylinder and the downward cylinder is controlled to move the rangefinder on the side of the steel-concrete composite column. The rangefinder measures the length and cross-sectional dimensions of the steel-concrete composite column and records the data.

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