Beam-column joint quasi-static test device capable of preventing out-of-plane bending and installation method of beam-column joint quasi-static test device

Abstract

The invention relates to the field of building structure stress experiment devices, in particular to a beam-column joint quasi-static test device capable of preventing out-of-plane bending and an installation method of the beam-column joint quasi-static test device. Comprising a foundation part, the foundation part comprises fixing assemblies and a square steel pipe, the fixing assemblies are divided into three groups, one group is connected to the midpoint position of the square steel pipe, and the other two groups are connected to the two sides of the square steel pipe in a left-right symmetry mode; a second support and a third support are respectively arranged above the plurality of fixing assemblies, the third support is connected above the fixing assembly at the midpoint position, the second support is connected above the fixing assemblies at the left and right positions, and a test piece fixing seat with an adjustable clamping space is arranged above the third support; the device can effectively fix the beam-column joint test piece, is suitable for test pieces of different sizes, is convenient to operate, is high in practicability, can reflect the condition of the beam-column joint under the action of an earthquake, and can research the hysteretic performance of the beam-column joint.

Description

Technical Field

[0001] The invention relates to the field of building structure stress test devices, in particular to a beam-column node quasi-static test device for preventing out-of-plane buckling and an installation method thereof. Background Art

[0002] In building structures, for composite frame structures, composite nodes are the key parts connecting composite beams and composite columns. For the seismic design of composite structures, the design principle of "strong columns and weak beams, stronger nodes" is generally followed to ensure the important position and role of nodes in structural seismic resistance.

[0003] The beam-column node is a key position where vertical and horizontal loads meet in the steel frame structure, which directly determines the mechanical performance and seismic resistance of the structure. In the seismic design, there are special regulations and limits on the shear bearing capacity of the core area of ​​the node to ensure the reliability of the node. At the same time, static tests are usually required to test the node conditions. However, in the existing experimental testing process, due to the unreasonable fixing structure of the beam body, it is often impossible to simulate the seismic performance of the node specimens under the action of earthquakes, resulting in inaccurate data. In addition, for specimens of different sizes, it is often necessary to readjust the fixation of the clamping point, which is time-consuming and labor-intensive and cannot meet the actual experimental needs. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a quasi-static test device for beam-column joints to prevent out-of-plane buckling and its installation method in response to the above-mentioned technical deficiencies. The device can effectively fix the beam body and is suitable for specimens of different sizes. It is easy to operate and has strong practicality. At the same time, it can reflect the condition of the beam-column joints under earthquake action and study the hysteresis performance of the beam-column joints.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention includes:

[0006] A base part, the base part comprises a fixing assembly and a square steel tube, the square steel tube (61) is provided with a compression beam (5) for fixing; the upper end of the column of the beam-column node specimen (1) is provided with a mounting screw (2); the fixing assembly is divided into three groups, one group is connected to the midpoint of the square steel tube, and the other two groups are symmetrically connected to the left and right sides of the square steel tube; a second support and a third support are respectively provided above the plurality of fixing assemblies, and the third support is connected to the top of the fixing assembly at the midpoint, the second support is connected to the top of the fixing assembly at the left and right positions, and the top of the third support is a specimen fixing seat with an adjustable clamping space;

[0007] A first support, the first support is installed on the second support, and is used to fix both ends of the beam-column node specimen, and an anti-bending component is installed on the upper end of the column of the beam-column node specimen;

[0008] The anti-bending assembly includes a roller, a sleeve and a box-type fastener; one end of the sleeve is in contact with the roller, and the other end is connected to the side limit steel beam; both ends of the side limit steel beam are provided with connecting plates connected to the reaction force bracket; the box-type fastener is installed on the beam-column node specimen and connected to the roller.

[0009] Preferably, the first support includes a steel plate, an ear plate and an end plate; the plurality of steel plates clamp the crossbeam of the beam-column node specimen through screws, and ear plates are welded on the steel plate and the end plate located below, respectively, and the ear plates are connected by pins.

[0010] Preferably, the second support and the third support are both formed by splicing ear plates and end plates.

[0011] Preferably, the steel plates include upper and lower steel plates and a middle steel plate, the upper and lower steel plates are in contact with the upper and lower surfaces of the beam-column node specimen respectively, the middle steel plate is embedded in the middle of the beam-column node specimen and connected by two screw rods.

[0012] Preferably, the specimen fixing seat comprises a grooved steel plate and a clamping steel plate; a plurality of fixing bolts are arranged on four sides of the grooved steel plate, and the clamping steel plate has reserved threaded holes connected with the fixing bolts.

[0013] Preferably, the fixing bolt is provided with a fixing nut in contact with the inner wall of the grooved steel plate.

[0014] Preferably, the clamping steel plates are composed of a plurality of spliced ​​pieces, and two adjacent clamping steel plates are connected by snap-fitting, so that a plurality of the clamping steel plates are spliced ​​together to form a wavy working surface.

[0015] Preferably, a vertical actuator in contact with the upper end of the column of the beam-column node specimen is provided on the reaction support, and a horizontal actuator fixed to the reaction wall is provided on one side of the cross beam in the beam-column node specimen.

[0016] Preferably, a mounting screw is provided at the upper end of the column of the beam-column node specimen.

[0017] Preferably, a pressure beam for fixing is provided on the square steel tube.

[0018] A method for installing a pseudo-static test device for beam-column joints to prevent out-of-plane buckling comprises the following steps:

[0019] S1, connecting the square steel pipe with a fixing assembly, and providing a pressure beam for fixing on the square steel pipe;

[0020] S2, connecting the second support and the third support to the fixing assembly respectively, connecting the first support above the second support, and connecting the specimen fixing seat above the third support;

[0021] S3, placing the bottom end of the specimen into the specimen fixing seat, adjusting the clamping space of the specimen fixing seat so that its size matches the bottom end of the specimen, connecting the steel plates with bolts, and finally setting a mounting screw at the top of the specimen;

[0022] S4. Use bolts to install the connecting plate at a suitable height of the reaction support, place the side limit steel beam above the connecting plate and fix it with an L-shaped steel plate and bolts, fix the sleeve to the side limit steel beam, fix the box-type fastener and roller to the mounting screw, and finally adjust the length of the sleeve to make the roller contact with the sleeve.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1. Through the cooperation between the support assembly and the specimen fixing seat, the various end points of the specimen can be effectively fixed and connected, thereby meeting the fixing requirements during the vibration test. At the same time, the specimen fixing seat can adjust the fixing space for the specimen column section, thereby meeting the fixation of specimens of different sizes. In combination with the structural form of the first support, it effectively solves the problem of large specimen size, difficult operation and large error in traditional tests;

[0025] 2. The contact surface between the clamping steel plate and the beam body adopts a wavy surface, which can effectively increase the friction between the clamping steel plate and the beam body and improve the stability after fixation. At the same time, the clamping steel plate is made of multiple groups of splicing and can be adjusted according to the size of the beam body fixing point, which is easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of specimen fixation in a quasi-static test device for beam-column joints to prevent out-of-plane buckling;

[0027] Figure 2 It is a three-dimensional schematic diagram of the fixing of the beam-column node specimen;

[0028] Figure 3 This is a schematic diagram of the reaction support installation;

[0029] Figure 4 This is the installation diagram of the side limit steel beam;

[0030] Figure 5 This is a partial enlarged view of point A;

[0031] Figure 6 This is a schematic diagram of the connection of the anti-bending component;

[0032] Figure 7 This is an enlarged schematic diagram of point B;

[0033] Figure 8 is a schematic diagram of the roller structure;

[0034] Fig. 9 It is a schematic diagram of the sleeve structure;

[0035] Fig.10 It is a schematic diagram of the connecting plate parts;

[0036] Fig.11 It is a schematic diagram of the specimen fixing seat structure;

[0037] Fig.12 Another structural schematic diagram of the specimen fixing seat.

[0038] In the figure: 1. Beam-column node specimen; 2. Mounting screw; 4. Specimen fixing seat; 5. Compression beam; 6. Foundation; 7. Vertical actuator; 8. Horizontal actuator; 11. Reaction bracket; 12. Connecting plate; 13. Lateral limit steel beam; 14. Anti-bending assembly; 31. First support; 32. Second support; 33. Third support; 41. Channel steel plate; 42. Clamping steel plate; 43. Fixing bolt; 44. Fixing nut; 61. Square steel pipe; 62. Fixing assembly; 141. Roller; 142. Sleeve; 143. Box-type fastener; 311. Steel plate; 312. Ear plate; 313. End plate. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0040] Specific implementation method 1: Combination Figure 1-12 As shown, a pseudo-static test device for beam-column joints to prevent out-of-plane buckling comprises: a base 6, the base 6 comprises a fixing assembly 62 and a square steel tube 61, the fixing assembly 62 is divided into three groups, one group is connected to the midpoint of the square steel tube 61, and the other two groups are symmetrically connected to both sides of the square steel tube 61 on the left and right; a second support 32 and a third support 33 are respectively arranged above the plurality of fixing assemblies 62, and the third support 33 is connected above the fixing assembly 62 at the midpoint, the second support 32 is connected above the fixing assembly 62 at the left and right positions, and a specimen fixing seat 4 with an adjustable clamping space is arranged above the third support 33;

[0041] A first support 31, the first support 31 is installed on the second support 32, and is used to fix the two ends of the beam-column node specimen 1, and an anti-bending component 14 is installed on the upper end of the column of the beam-column node specimen 1;

[0042] The anti-bending assembly 14 includes a roller 141, a sleeve 142 and a box-type fastener 143; one end of the sleeve 142 is in contact with the roller 141, and the other end is connected to the side limit steel beam 13; both ends of the side limit steel beam 13 are provided with connecting plates 12 connected to the reaction force bracket 11; the box-type fastener 143 is installed on the beam-column node specimen 1 and connected to the roller 141.

[0043] A preferred embodiment, in combination with Figure 2 As shown, the first support 31 includes a steel plate 311, an ear plate 312 and an end plate 313; the multiple steel plates 311 are clamped and fixed to the beam body by screws, and the ear plate 312 is arranged on the steel plate 311 located at the bottom, and the other ear plate 312 is welded to the end plate 313. The overall structure is easy to install and disassemble, wherein the ear plate 312 is in a door arch shape, and after stacking, it is connected together by a pin at the door arch position, so that the ear plate 312 can rotate in a plane with the pin as the center, and the end plate 313 is arranged in multiple groups, and support is achieved in the middle by screws and nuts.

[0044] A preferred embodiment, combined with Figure 1 As shown, the second support 32 and the third support 33 are also made of ear plates 312 and end plates 313. Specifically, the second support 32 includes an end plate 313 located at the bottom, on which an ear plate 312 is welded, and there is also an end plate 313 located at the top, under which an ear plate 312 is also welded. The two ear plates 312 are connected by a pin to achieve the connection between the two end plates 313, and then the end plate 313 on the first support 31 is connected by a screw. Specifically, two nuts are respectively provided on the screw, which respectively contact the top and bottom of the end plate 313 to achieve positioning. After installation, the relative heights of the two nuts can be adjusted to adjust the height of the end plate 313, thereby achieving the adjustment of the height of the first support 31 to meet the fixation of beam-column node specimens 1 of different heights.

[0045] In a preferred embodiment, the steel plate 311 comprises an upper steel plate, a lower steel plate and a middle steel plate, the upper steel plate and the lower steel plate are in contact with the upper surface and the lower surface of the beam-column node specimen 1 respectively, the middle steel plate is embedded in the middle of the beam-column node specimen 1 and connected by two screw rods; the steel plate 311 is arranged in a three-layer structure, the upper and lower steel plates 311 are in contact with the upper surface and the lower surface of the beam respectively, and the middle steel plate 311 is embedded in the beam, which effectively improves the firmness after fixation.

[0046] A preferred embodiment, combined with Fig.11As shown, the specimen fixing seat 4 includes a grooved steel plate 41 and a clamping steel plate 42; a plurality of fixing bolts 43 are provided on the four sides of the grooved steel plate 41, and the fixing bolts 43 are threadedly connected to the grooved steel plate 41. By cooperating with the fixing bolts 43 and the inner threads of the reserved holes of the grooved steel plate 41, the relative position of the clamping steel plate 42 can be changed to meet the needs of columns of different sizes; wherein, the grooved steel plate 41 has reserved threaded holes connected to the fixing bolts 43.

[0047] In a preferred embodiment, the working surface of a single clamping steel plate 42 is in the shape of an arc protrusion, and a plurality of plates are spliced ​​together to form a wavy working surface, thereby increasing the friction between the clamping steel plate 42 and the specimen and better fixing the beam-column node specimen 1.

[0048] In a preferred embodiment, a fixing nut 44 is provided on the fixing bolt 43 and contacts the inner wall of the grooved steel plate 41 , so as to play a pre-tightening role and prevent the fixing bolt 43 from rotating under force.

[0049] A preferred embodiment, combined with Fig.11 As shown, the clamping steel plate 42 is composed of multiple pieces spliced ​​together, and two adjacent clamping steel plates 42 are connected by snap-fitting. The specific structure is that one side of the clamping steel plate 42 has a rectangular groove, and the other side has a rectangular protrusion. By snapping the groove and the protrusion, it can adapt to the contact between columns of different sizes.

[0050] In a preferred embodiment, for the connection between the fixing bolt 43 and the clamping steel plate 42, the fixing bolt 43 can pass through the grooved steel plate 41, and the clamping steel plate 42 is pushed to move by rotating the fixing nut 44, and the end of the fixing bolt 43 is in contact with the clamping steel plate 42; the fixing bolt 43 and the grooved steel plate 41 can also be threadedly connected.

[0051] A preferred embodiment, combined with Figure 3 As shown, a vertical actuator 7 in contact with the upper end of the column of the beam-column node specimen 1 is provided on the reaction support 11, and a horizontal actuator 8 fixed to the reaction wall is provided on one side of the cross beam in the beam-column node specimen 1, and the reaction wall is arranged on one side of the reaction support 11; a box-type fastener 143 is installed on the upper end of the specimen and connected to the roller 141, which can effectively prevent the specimen from moving on a plane perpendicular to the horizontal actuator, wherein the roller 141 and the box-type fastener 143 are welded.

[0052] A preferred embodiment, combined with Figure 5 and Fig.10As shown, both ends of the side limit steel beam 13 are provided with connecting plates 12 connected to the reaction support 11, and the connecting plate 12 has a first through hole, which is connected to the hole position on the reaction support 11 by passing bolts through the first through hole to achieve the installation of the connecting plate 12. At the same time, two bolts are welded on the connecting plate 12, and an L-shaped steel is used to connect the side limit steel beam 13, which can improve the stability of the anti-bending component 14 after being fixed.

[0053] A preferred embodiment, combined with Figure 7 As shown, a mounting screw 2 is provided at the upper end of the test piece, and the mounting screw 2 is connected to the box-type fastener 143. The two mounting screws 2 are respectively in contact with the upper and lower parts of the box-type fastener 143 to achieve positioning.

[0054] A preferred embodiment, combined with Figure 1 and Figure 2 As shown, a fixing assembly 62 is provided below the first support 31, the second support 32 and the third support 33; the base 6 includes a fixing assembly 62 and a square steel tube 61, wherein the fixing assembly 62 is fixed outside the square steel tube 61, and the fixing assembly 62 is composed of upper and lower horizontally arranged steel plates, a middle vertically arranged steel plate, and stiffening ribs welded on both sides in combination with bolts, and is connected and fixed to the square steel tube 61 by tightening the bolts to improve the tightness of the connection, the upper steel plate is connected to the second support 32, and there is a notch between the middle vertically arranged steel plates, and the width of the notch is the same as the size of the square steel tube 61, so as to realize the connection between the fixing assembly 62 and the square steel tube 61, and it can also slide along the square steel tube 61, and after sliding to the specified position, it is connected by bolts, and its own position can be adjusted according to the condition of the specimen.

[0055] In a preferred embodiment, a pressure beam 5 for fixing is provided on the square steel pipe 61, and the ground serves as the base of the whole, and there are ground anchor holes inside the pressure beam 5. Both end portions of the pressure beam 5 have installation grooves of a certain length, and screws are passed through the installation grooves and connected to the ground anchor holes, so that the overall firmness can be improved.

[0056] In a preferred embodiment, concrete can be poured inside the square steel tube 61 to improve its foundation strength. Specific implementation method 2

[0058] The beam-column node specimen 1, each support, the specimen fixing seat 4 and the foundation 6 are respectively provided with reserved bolt holes at corresponding positions, so that the components can be installed better.

[0059] In a preferred embodiment, the end plate 313 on the third support 33 is welded to the specimen fixing seat 4, and the lower end plate 313 is connected to the base 6 by bolts, so that the specimen fixing seat 4 and the base 6 have a better connection.

[0060] In a preferred embodiment, the square steel tube 61 is located in a reserved hole between the middle vertical steel plate and the upper and lower horizontal steel plates of the fixing assembly 62, wherein the spacing between the middle vertical steel plates is the width of the square steel tube 61, and the spacing between the upper and lower horizontal steel plates is the height of the square steel tube 61.

[0061] During the experiment, the vertical actuator 7 loads axial pressure on the column section of the beam-column node specimen 1, and the horizontal actuator 8 loads horizontal pressure on the beam section of the beam-column node specimen 1. The vertical actuator 7 and the horizontal actuator 8 work together to accurately apply the axial pressure ratio required for the experiment to the beam-column node specimen 1, which can reflect the condition of the beam-column node under the action of an earthquake. The anti-bending component can limit the beam-column node specimen to prevent the specimen from deviating in the direction perpendicular to the horizontal actuator, thereby ensuring the stability of the specimen and improving the accuracy of the test.

[0062] The specific installation is as follows: when installing the beam-column node specimen 1, first place the specimen column section in the specimen fixing seat 4 for fixing, then adjust the height of the first support 31 and the second support 32 at both ends according to the size of the specimen, so that the support is connected to the beam end to achieve the balance of the specimen, and finally use the screw to connect the steel plate 311 to clamp and fix the specimen beam end, and finally adjust the vertical actuator 7 and the horizontal actuator 8 to the corresponding positions of the column section and the beam section. After the overall fixation, the reliability of the fixation can be guaranteed, and the fixation in the actual building can be accurately simulated. At the same time, the device can be adapted to experiments on beam-column nodes of different sizes. Specific implementation method three

[0064] A method for installing a pseudo-static test device for beam-column joints to prevent out-of-plane buckling comprises the following steps:

[0065] S1, connecting the square steel tube 61 with the fixing assembly 62, and providing a pressure beam 5 for fixing on the square steel tube 61;

[0066] S2, respectively connect the second support 32 and the third support 33 to the fixing assembly 62, connect the first support 31 above the second support 32, and connect the specimen fixing seat 4 above the third support 33;

[0067] S3, place the bottom end of the specimen into the specimen fixing seat 4, and adjust the clamping space of the specimen fixing seat 4 so that its size matches the bottom end of the specimen, connect the steel plate 311 with bolts, and finally set the mounting screw 2 at the top of the specimen;

[0068] S4. Use bolts to install the connecting plate 12 at a suitable height on the reaction support 11, place the side limit steel beam 13 above the connecting plate 12 and fix it with an L-shaped steel plate and bolts, fix the sleeve (142) on the side limit steel beam, fix the box-type fastener 143 and the roller 141 on the installation screw 2, and finally adjust the length of the sleeve 142 so that the roller 141 contacts the sleeve 142.

[0069] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or the equivalent forms of such scope and boundaries.

Claims

1. A quasi-static test device for beam-column joints to prevent out-of-plane buckling, characterized in that: include: A base part (6), the base part (6) comprising a fixing assembly (62) and a square steel tube (61), the square steel tube (61) being provided with a compression beam (5) for fixing; a mounting screw (2) being provided at the upper end of the column of the beam-column node specimen (1); the fixing assembly (62) being divided into three groups, one group being connected to the midpoint of the square steel tube (61), and the other two groups being symmetrically connected to the left and right sides of the square steel tube (61); a second support (32) and a third support (33) being provided above the plurality of fixing assemblies (62), and the third support (33) being connected above the fixing assembly (62) at the midpoint; the second support (32) being connected above the fixing assemblies (62) at the left and right positions, and a specimen fixing seat (4) having an adjustable clamping space being provided above the third support (33); A first support (31), the first support (31) being mounted on the second support (32) and used for fixing the two ends of the beam-column node specimen (1), and an anti-bending component (14) being mounted on the upper end of the column of the beam-column node specimen (1); The anti-bending component (14) comprises a roller (141), a sleeve (142) and a box-type fastener (143); one end of the sleeve (142) contacts the roller (141), and the other end is connected to the side limit steel beam (13); both ends of the side limit steel beam (13) are provided with connecting plates (12) connected to the reaction force bracket (11); the box-type fastener (143) is installed on the beam-column node specimen (1) and connected to the roller (141).

2. The quasi-static test device for beam-column joints to prevent out-of-plane buckling according to claim 1, characterized in that: The first support (31) comprises a steel plate (311), an ear plate (312) and an end plate (313); the plurality of steel plates (311) clamp the crossbeam of the beam-column node specimen (1) via screws, and the ear plates (312) are respectively welded to the steel plate (311) and the end plate (313) at the bottom, and the ear plates (312) are connected via pins.

3. The quasi-static test device for beam-column joints to prevent out-of-plane buckling according to claim 2, characterized in that: The second support (32) and the third support (33) are both formed by splicing ear plates (312) and end plates (313).

4. The quasi-static test device for beam-column joints to prevent out-of-plane buckling according to claim 2, characterized in that: The steel plate (311) comprises an upper steel plate, a lower steel plate and a middle steel plate. The upper steel plate and the lower steel plate are in contact with the upper surface and the lower surface of the beam-column node specimen (1) respectively. The middle steel plate is pre-embedded in the middle of the beam-column node specimen (1) and connected by two screw rods.

5. The quasi-static test device for beam-column joints to prevent out-of-plane buckling according to claim 1, characterized in that: The specimen fixing seat (4) comprises a grooved steel plate (41) and a clamping steel plate (42); a plurality of fixing bolts (43) are arranged on four sides of the grooved steel plate (41), and the grooved steel plate (41) has reserved threaded holes connected to the fixing bolts (43).

6. The quasi-static test device for beam-column joints to prevent out-of-plane buckling according to claim 5, characterized in that: The fixing bolt (43) is provided with a fixing nut (44) which contacts the inner wall of the grooved steel plate (41).

7. The quasi-static test device for beam-column joints to prevent out-of-plane buckling according to claim 5, characterized in that: The clamping steel plates (42) are assembled by splicing multiple pieces, and two adjacent clamping steel plates (42) are connected by snap-fitting, so that a plurality of the clamping steel plates (42) are spliced ​​together to form a wavy working surface.

8. The quasi-static test device for beam-column joints to prevent out-of-plane buckling according to claim 1, characterized in that: The reaction support (11) is provided with a vertical actuator (7) in contact with the upper end of the column of the beam-column node specimen (1), and a horizontal actuator (8) fixed to the reaction wall is provided on one side of the cross beam in the beam-column node specimen (1).

9. The quasi-static test device for beam-column joints to prevent out-of-plane buckling according to claim 1, characterized in that: The upper end of the column of the beam-column node specimen (1) is provided with a mounting screw rod (2).

10. A method for installing the quasi-static test device for beam-column joints to prevent out-of-plane buckling according to claim 1, characterized in that: The steps include: S1, connecting the square steel tube (61) to the fixing assembly (62), and providing a pressure beam (5) for fixing on the square steel tube (61); S2, respectively connecting the second support (32) and the third support (33) to the fixing assembly (62), connecting the first support (31) above the second support (32), and connecting the specimen fixing seat (4) above the third support (33); S3, placing the bottom end of the specimen into the specimen fixing seat (4), adjusting the clamping space of the specimen fixing seat (4) so ​​that its size matches the bottom end of the specimen, connecting the steel plate (311) with bolts, and finally setting a mounting screw (2) at the top end of the specimen; S4. Use bolts to install the connecting plate (12) at a suitable height on the reaction support (11), place the side limit steel beam (13) above the connecting plate (12) and fix it with an L-shaped steel plate and bolts, fix the sleeve (142) on the side limit steel beam, fix the box-type fastener (143) and the roller (141) on the installation screw (2), and finally adjust the length of the sleeve (142) so that the roller (141) contacts the sleeve (142).

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