Steel lattice column eccentric compression loading device and loading method using same

Abstract

This invention belongs to the field of experimental technology for eccentrically compressed components, specifically relating to an eccentrically compressed loading device for steel lattice columns and its loading method. It includes a test bench, with an upper loading component fixed to the upper end of the test bench. The upper loading component is fixedly connected to a vertical reaction frame via a constraint component. The upper loading component includes a loading box component, with a steel sleeve structure externally disposed on the loading box component. The steel sleeve structure is fixedly connected to the side wall of the actuator cylinder via turnbuckles. A hydraulic actuator and an eccentric structure are disposed between the actuator cylinder and the steel sleeve structure. This invention closely matches the boundary conditions and stress state of eccentrically compressed steel lattice columns with rigid column bases and hinged column tops in actual engineering. It effectively solves the problems of localized damage to the steel column head and the tendency for overall in-plane lateral displacement of steel lattice columns during eccentric loading. It exhibits strong experimental stability, convenient installation, and simple operation, and can meet the requirements for eccentric loading devices for other types of large-size steel components.

Description

Technical Field

[0001] This invention belongs to the field of experimental technology for eccentrically compressed components, specifically relating to an eccentrically compressed loading device for steel lattice columns and a loading method using the same. Background Technology

[0002] In steel structure engineering, steel lattice columns are a crucial and highly efficient compression member. Through the combination of structural members (sections of steel (angle steel, channel steel, I-beams, and steel pipes) or welded composite sections) and lacing materials (lacing strips or plates), they achieve an optimal balance of material strength and stability. This is a classic and economical solution for addressing the vertical load-bearing problems of tall, large, and heavy structures. As eccentrically compressed members, steel lattice columns are widely used in medium- and heavy-duty industrial plants, large-span public buildings, high-rise buildings, bridges, and special structures. Therefore, it is necessary to conduct research on the mechanical properties of steel lattice columns under eccentric compression.

[0003] Currently, the classic apparatus for eccentric compression testing of steel members is the knife-edge hinged support at both ends. This is a statically determinate structure, and its internal force calculations perfectly match the theoretical models of mechanics of materials and structural mechanics. Test data is easily compared with theoretical solutions. Furthermore, the knife-edge hinge is easy to manufacture, requires no complex horizontal restraint structures, and the apparatus is quick to assemble and convenient to maintain, making it widely used in eccentric compression testing of members under small to medium loads. However, when the load is relatively large, stress concentration easily occurs at the knife-edge, leading to support failure. On the other hand, the knife-edge hinge can hardly restrict horizontal displacement, and the member is prone to out-of-plane overall lateral displacement under eccentric loading, significantly affecting the accuracy of the test results. More importantly, purely "ideal hinged" columns at both ends are rare in actual engineering, limiting the direct guiding significance of the test results for engineering projects. Therefore, for practical engineering projects, such as medium to heavy-duty industrial building columns with steel-jointed column bases and hinged column tops, a precise loading device design is needed to ensure that the stress state of the test member is highly consistent with that of the actual project, allowing the test results to directly guide engineering design. Summary of the Invention

[0004] This invention addresses the problem of inaccurate experimental results in the prior art by providing an eccentric compression loading device for steel lattice columns and a loading method using it.

[0005] To achieve the above objectives, the present invention employs the following technical solution: An eccentric compression loading device for steel lattice columns includes a test bench, an upper loading component fixed to the upper end of the test bench, the upper loading component being fixedly connected to a vertical reaction frame via a constraint component, the upper loading component including a loading box component, a steel sleeve structure being provided on the outside of the loading box component, the steel sleeve structure being fixedly connected to the side wall of the actuator cylinder by turnbuckles, and a hydraulic actuator and an eccentric structure being provided between the actuator cylinder and the steel sleeve structure; The steel sleeve structure includes a rectangular frame, on which auxiliary supports are evenly arranged on two adjacent outer side walls. Each auxiliary support has two bolt holes on its outer side wall, through which it is threadedly fixed to a constraint component. A first-order U-shaped steel bar is located at a corner of the rectangular frame away from the auxiliary supports, and this first-order U-shaped steel bar is fixedly connected to the upper part of the outer side wall of the rectangular frame. A second-order U-shaped steel bar is symmetrically arranged on both sides of the upper end face of one auxiliary support. A third-order U-shaped steel bar is located on the upper end face of the other auxiliary support, away from the second-order U-shaped steel bar. Turnbuckles are connected to the first, second, and third-order U-shaped steel bars via steel wire. A loading box component is installed within the rectangular frame.

[0006] Furthermore, the auxiliary support includes four vertical steel plates, one side of which is welded to the outer wall of the rectangular frame, and the other side of the four vertical steel plates is welded together to an end plate. Two bolt holes are opened on the side wall of the end plate, and the end plate is fixedly connected to the constraint component.

[0007] Furthermore, the constraint component includes two high-strength lead screws, one end of which is threaded to a bolt hole, and the other end of which is threaded to a support plate. One end of the support plate is welded to a square tube, and the other end of the square tube is fixedly installed on the side wall of the vertical reaction frame by bolts.

[0008] Furthermore, the test bench includes a base plate, with anchor holes at both ends of the base plate. Precision rolled threaded steel bars are threaded into the anchor holes. A steel lattice column is welded to the upper surface of the base plate, and a top plate is fixedly connected to the upper surface of the steel lattice column. The top plate is threadedly connected to a loading box component. Two flange plates are respectively provided on the I-shaped limbs on both sides of the steel lattice column. A vertical plate is provided between the two flange plates. Stiffening plates are fixedly installed on the outer walls of both the vertical plate and the flange plates. The lower surfaces of both the vertical plate and the stiffening plates are fixedly connected to the base plate.

[0009] Furthermore, the loading box component includes a support frame, which includes a longitudinal vertical plate. Two transverse vertical plates are symmetrically welded to both sides of the longitudinal vertical plate. Fixing plates are welded to the upper, lower, left, and right ends of the support frame. The fixing plate on the lower end is threadedly fixed to the top plate, and an eccentric structure is provided on the fixing plate on the upper end.

[0010] Furthermore, the eccentric structure includes two limiting steel bars, which are fixedly mounted in parallel on a fixing plate on the upper surface of the reinforcing plate and are located on one side of the fixing plate. A roller is provided on both limiting steel bars, and a baffle is welded to the upper end of the roller. A hydraulic actuator is fixedly connected to the upper surface of the baffle by bolts, and an actuator cylinder is fixedly mounted on the upper end of the hydraulic actuator.

[0011] Furthermore, a polytetrafluoroethylene (PTFE) sliding plate is attached to the inner wall of the rectangular frame.

[0012] Furthermore, the gap between the rectangular frame and the fixing plate is set to 2-4mm.

[0013] Furthermore, horizontal displacement gauges are respectively installed on the two end faces of the rectangular frame away from the constraint components, and the horizontal displacement gauges detect the horizontal displacement of the steel lattice column.

[0014] An eccentric compression loading device for steel lattice columns and a loading method using the same. Step 1: Install and fix the test bench to achieve bottom fixed end constraint. Weld the column base of the steel lattice column to the base plate, and use high-tonnage anchoring force through the anchor holes on both sides of the base plate to fix the test bench to the ground. This operation completely restricts all translation and rotation of the test bench, forming a fixed end constraint without displacement or rotation. Step 2: Assemble the eccentric structure and constraint components, establish composite boundary conditions, weld the rollers to the baffle and connect them to the hydraulic actuator. Align the rollers between the limiting steel bars placed on top of the loading box component. At the same time, connect the steel sleeve structure of the ring-shaped loading box component to the constraint components and fix it with turnbuckles. The eccentric structure and constraint components shown allow vertical displacement and rotation around the axis at the top of the column, but effectively limit the X / Y displacement through horizontal constraints, forming a composite constraint. Step 3: Adjust the eccentricity and complete the loading centering. According to the target eccentricity, adjust the relative position of the hydraulic actuator and the loading box component so that the straight line where the lower quadrant point of the roller is located is aligned with the symmetrical center line between the two limit steel bars. Use an external high-precision infrared level to check and ensure that the loading axis and the centroid of the column section maintain the set eccentricity to achieve precise centering. Step 4: Apply load and verify device reliability. Connect the external hydraulic control system and apply vertical eccentric pressure in stages according to the preset system. During the loading process, verify the effectiveness of the horizontal constraint by monitoring the horizontal displacement, and verify the hinge rotation performance by comparing the vertical displacement of the loaded side and the unloaded side. If the data meets the expectations, it indicates that the device is operating reliably and the boundary conditions have been successfully achieved.

[0015] Compared with the prior art, the present invention has the following advantages: 1. Stable and reliable constraint system: The present invention uses a high-strength screw to connect the auxiliary support and the vertical reaction frame, combined with a horizontal constraint system composed of turnbuckles and No. 1 U-shaped steel bars, No. 2 U-shaped steel bars and No. 3 U-shaped steel bars, to achieve multi-point and adjustable horizontal constraint on the loading box structure. This effectively solves the problem that the roller support can hardly limit the horizontal displacement, which leads to the easy occurrence of overall lateral displacement of the component in the plane during eccentric loading, thus ensuring the stability of the test process.

[0016] 2. Highly efficient eccentric loading capability: The upper end of the loading box component of this invention is provided with an eccentric structure consisting of a steel bar, a roller and a baffle, which enables the hydraulic actuator to apply pressure that deviates from the axis of the specimen while realizing the roller hinge support at the top of the column, accurately simulating the eccentric force state in actual engineering.

[0017] 3. High rigidity and precise positioning of the force transmission path: The loading box component of this invention is composed of a support frame and a multi-faceted welded fixing plate, and is connected to the top plate of the test bench and the upper eccentric structure by threads, forming a loading channel with high rigidity, direct force transmission and precise positioning, effectively solving the problem of local crushing of the steel column head.

[0018] 4. Anti-lateral displacement and low friction design: The inner wall of the rectangular frame of the steel sleeve structure of the present invention is bonded with polytetrafluoroethylene sliding plate, and a 2-4mm gap is preset between the rectangular frame and the loading box fixing plate. On the one hand, it significantly reduces the frictional resistance when the loading box slides in the constraint frame, and on the other hand, it reduces the interference of the horizontal constraint. This ensures the vertical displacement and rotation around the axis of the column top, while controlling the excessive lateral displacement of the column head.

[0019] 5. High load-bearing capacity and stable test bench: The test bench of this invention adopts a base plate with a welded structure of anchor holes, steel lattice columns, top plate and stiffening plate, and is fixed to the ground by high-strength anchoring force through finely rolled threaded steel, providing an extremely stable foundation for the entire loading system and capable of withstanding large tonnage eccentric pressure.

[0020] 6. Modularity and adjustability: The design of the turnbuckle connection U-shaped steel bar and the application of high-strength screw in this invention allow the position and preload of the horizontal constraint to be adjusted according to the test requirements, enhancing the adaptability and flexibility of the device. The auxiliary support is also easy to connect with the constraint system through the cooperation of the vertical steel plate and the end plate.

[0021] 7. The boundary conditions and stress state of the eccentrically compressed steel lattice column with rigid column base and hinged column top in actual engineering are highly consistent. It can effectively solve the problems of local crushing of steel column head and easy in-plane overall lateral displacement of steel lattice column under eccentric loading. It has strong experimental stability, is easy to install and operate, and can meet the requirements of eccentric loading devices for other types of large-size steel components. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the loading box component of the present invention; Figure 3 This is a schematic diagram of the steel sleeve structure of the present invention; Figure 4 This is a schematic diagram of the constraint component structure of the present invention; Figure 5 This is a schematic diagram of the column base device of the present invention; Figure 6 This is a schematic diagram of the eccentric structure of the present invention; In the figure, the test bench 1, base plate 101, anchor holes 102, precision rolled threaded steel bar 103, steel lattice column 104, top plate 105, flange plate 106, vertical plate 107, stiffening plate 108, upper loading component 2, constraint component 3, high-strength screw 301, support plate 302, square tube 303, vertical reaction frame 4, loading box component 5, support frame 501, fixing plate 502, steel sleeve structure 6, rectangular frame 601, auxiliary support 602, vertical steel plate 6021, end plate 6022, bolt hole 603, No. 1 U-shaped steel bar 604, No. 2 U-shaped steel bar 605, No. 3 U-shaped steel bar 606, turnbuckle 7, actuator cylinder 8, hydraulic actuator 9, eccentric structure 10, limit steel bar 1001, roller 1002, baffle 1003. Detailed Implementation

[0023] To further illustrate the technical solution of the present invention, the present invention will be further described below through embodiments.

[0024] like Figures 1-4 As shown, an eccentric compression loading device for steel lattice columns includes a test bench 1. An upper loading component 2 is fixed to the upper end of the test bench 1. The upper loading component 2 is fixedly connected to a vertical reaction frame 4 through a constraint component 3. The upper loading component 2 includes a loading box component 5. A steel sleeve structure 6 is provided on the outside of the loading box component 5. The steel sleeve structure 6 is fixedly connected to the side wall of an actuator cylinder 8 through turnbuckles 7. A hydraulic actuator 9 and an eccentric structure 10 are provided between the actuator cylinder 8 and the steel sleeve structure 6. like Figure 3As shown, the steel sleeve structure 6 includes a rectangular frame 601. A polytetrafluoroethylene (PTFE) sliding plate is adhered to the inner wall of the rectangular frame 601. Horizontal displacement gauges are respectively installed on the two end faces of the rectangular frame 601 away from the constraint component 3. The horizontal displacement gauges detect the horizontal displacement of the steel lattice column 104. The internal dimensions of the rectangular frame are 450mm in length and 446mm in width. Auxiliary supports 602 are evenly arranged on two adjacent outer walls of the rectangular frame 601. Two bolt holes 603 are provided on the outer wall of each auxiliary support 602. Each auxiliary support 602 includes four vertical steel plates 6021. One side of each vertical steel plate 6021 is welded to the outer wall of the rectangular frame 601, and the other side of the four vertical steel plates 6021 is welded to an end plate 6022. On the side wall of the end plate 6022... Two bolt holes 603 are provided. The end plate 6022 is fixedly connected to the constraint component 3 through the bolt holes 603. A first U-shaped steel bar 604 is provided at the corner of the rectangular frame 601 away from the auxiliary support 602. The first U-shaped steel bar 604 is fixedly connected to the upper part of the outer wall of the rectangular frame 601. A second U-shaped steel bar 605 is provided on both sides of the upper end face of the auxiliary support 602 on one side. The two second U-shaped steel bars 605 are symmetrically arranged. A third U-shaped steel bar 606 is provided on the upper end face of the auxiliary support 602 away from the second U-shaped steel bar 605 on the other side. Turnbuckles 7 are connected to the first U-shaped steel bar 604, the second U-shaped steel bar 605 and the third U-shaped steel bar 606 by steel wire. A loading box component 5 is provided inside the rectangular frame 601.

[0025] like Figure 4 As shown, the constraint component 3 includes two 12.9 grade M30 high-strength lead screws 301. One end of the high-strength lead screw 301 is threaded to a bolt hole 603, and the other end of the high-strength lead screw 301 is threaded to a support plate 302. One end of the support plate 302 is welded to a square tube 303, and the other end of the square tube 303 is fixedly installed on the side wall of the vertical reaction frame 4 by bolts.

[0026] like Figure 6As shown, the test bench 1 includes a base plate 101. Anchor holes 102 are respectively provided at both ends of the base plate 101. A precision-rolled threaded steel bar 103 is threadedly connected to the anchor holes 102. The diameter of a single precision-rolled threaded steel bar 103 is set to 30-32mm. A steel lattice column 104 is welded to the upper end face of the base plate 101. A top plate 105 is fixedly connected to the upper end face of the steel lattice column 104. The top plate 105 is threadedly connected to the loading box component 5. Two flange plates 106 are respectively provided on the I-shaped branches on both sides of the steel lattice column 104. A vertical plate 107 is provided between the two flange plates 106. A stiffening plate 108 is fixedly installed on the outer side wall of both the vertical plate 107 and the flange plate 106. The lower end face of both the vertical plate 107 and the stiffening plate 108 is fixedly connected to the base plate 101.

[0027] like Figure 2 As shown, the loading box component 5 includes a support frame 501, which includes a longitudinal vertical plate. Two transverse vertical plates are symmetrically welded to both sides of the longitudinal vertical plate. The thickness of the longitudinal and transverse vertical plates is set to 16mm. Fixing plates 502 are welded to the upper, lower, left, and right ends of the support frame 501. The dimensions of the fixing plates 502 on the upper and lower ends are 30x442x442mm, and the dimensions of the fixing plates 502 on the left and right ends are 16x125x442mm. The fixing plates 502 are threadedly fixed to the top plate 105. An eccentric structure 10 is provided on the upper end of the fixing plate 502. The gap between the rectangular frame 601 and the fixing plates 502 is set to 2-4mm.

[0028] like Figure 5 As shown, the eccentric structure 10 includes two limiting steel bars 1001 with a diameter of 30mm. The two limiting steel bars 1001 are fixedly installed in parallel on the fixing plate 502 on the upper end face of the support frame 501 and are located on one side of the fixing plate 502. A roller 1002 is provided on both limiting steel bars 1001. A baffle 1003 is welded to the upper end of the roller 1002. The upper end face of the baffle 1003 is fixedly connected to the hydraulic actuator 9 by bolts. An actuator cylinder 8 is fixedly installed on the upper end of the hydraulic actuator 9.

[0029] An eccentric compression loading device for steel lattice columns and a loading method using the same. Step 1: Install and fix the test bench 1 to achieve bottom fixed end constraint. Weld the column base of the steel lattice column 104 to the base plate 101. Through the anchor holes 102 on both sides of the base plate 101, use high-tonnage anchoring force with fine-rolled threaded steel bars 103. Each fine-rolled threaded steel bar 103 applies an anchoring force of 50 tons to anchor the base plate 101 to the ground and fix the test bench 1 to the ground. This operation completely restricts all translation and rotation of the test bench 1, forming a fixed end constraint without displacement or rotation. Step 2: Assemble the eccentric structure 10 and the constraint component 3, establish composite boundary conditions, weld the roller 1002 to the baffle 1003 and connect it to the hydraulic actuator 9, align the roller 1002 with the limiting steel bar 1001 placed on the top of the loading box component 5, and connect the steel sleeve structure 6 of the ring-shaped loading box component 5 to the constraint component 3 and fix it with turnbuckle 7. The eccentric structure 10 and the constraint component 3 shown allow vertical displacement and rotation around the axis at the top of the column, but effectively limit the X / Y displacement through horizontal constraints, forming a composite constraint of upper hinge + horizontal constraint. Step 3: Adjust the eccentricity and complete the loading centering. According to the target eccentricity, adjust the relative position of the hydraulic actuator 9 and the loading box component 5 so that the straight line where the lower quadrant point of the roller 1002 is located is aligned with the symmetrical center line between the two limit steel bars 1001. Use an external high-precision infrared level to check and ensure that the loading axis and the centroid of the column section maintain the set eccentricity to achieve precise centering. Step 4: Apply load and verify device reliability. Connect the external hydraulic control system and apply vertical eccentric pressure in stages according to the preset system. During the loading process, in order to verify the effectiveness of the two horizontal constraint components 3 at the top of the steel lattice column 104, the steel sleeve structure 6 is connected to the constraint components 3 on both adjacent sides. In addition, horizontal displacement gauges are connected to the adjacent sides to monitor the horizontal displacement. The horizontal displacement is monitored throughout the loading process by the displacement gauges. As shown in Table 1, the horizontal displacement is close to zero, indicating that the horizontal constraint device of this invention can effectively limit the horizontal displacement of the top of the steel lattice column 104 in the X / Y directions. The data meets the expectations, which indicates that the device is operating reliably and the boundary conditions are successfully achieved.

[0030] The specific experimental data are as follows:

[0031] Table 1 Vertical displacement (mm) of steel lattice column on loaded and unloaded sides The foregoing has shown and described the main features and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0032] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A steel lattice column eccentric compression loading device, characterized in that: The test bench (1) is provided with an upper loading component (2) fixed at its upper end. The upper loading component (2) is fixedly connected to the vertical reaction frame (4) through a constraint component (3). The upper loading component (2) includes a loading box component (5). A steel sleeve structure (6) is provided on the outside of the loading box component (5). The steel sleeve structure (6) is fixedly connected to the side wall of the actuator cylinder (8) through turnbuckles (7). A hydraulic actuator (9) and an eccentric structure (10) are provided between the actuator cylinder (8) and the steel sleeve structure (6). The steel sleeve structure (6) includes a rectangular frame (601). Auxiliary supports (602) are evenly distributed on two adjacent outer side walls of the rectangular frame (601). Two bolt holes (603) are provided on the outer side walls of the auxiliary supports (602), and are threadedly fixed to the constraint components (3) through the bolt holes (603). A first U-shaped steel bar (604) is provided at the corner of the rectangular frame (601) away from the auxiliary supports (602), and the first U-shaped steel bar (604) is fixedly connected to the outer side wall of the rectangular frame (601). The upper part of the auxiliary support (602) has a No. 2 U-shaped steel bar (605) on each side of the upper end face of one side, and the two No. 2 U-shaped steel bars (605) are arranged symmetrically. The No. 3 U-shaped steel bar (606) is arranged on the side of the upper end face of the auxiliary support (602) away from the No. 2 U-shaped steel bar (605). Turnbuckles (7) are connected to the No. 1 U-shaped steel bar (604), No. 2 U-shaped steel bar (605) and No. 3 U-shaped steel bar (606) by steel wire. The rectangular frame (601) is equipped with a loading box component (5).

2. The eccentric compression loading device for steel lattice columns according to claim 1, characterized in that: The auxiliary support (602) includes four vertical steel plates (6021). One side of the vertical steel plates (6021) is welded to the outer wall of the rectangular frame (601). The other side of the four vertical steel plates (6021) is welded together to an end plate (6022). Two bolt holes (603) are opened on the side wall of the end plate (6022). The end plate (6022) is fixedly connected to the constraint component (3).

3. The eccentric compression loading device for steel lattice columns according to claim 2, characterized in that: The constraint component (3) includes two high-strength lead screws (301), one end of which is threaded to a bolt hole (603), and the other end of which is threaded to a support plate (302). One end of the support plate (302) is welded to a square tube (303), and the other end of the square tube (303) is fixedly installed on the side wall of the vertical reaction frame (4) by bolts.

4. The eccentric compression loading device for steel lattice columns according to claim 1, characterized in that: The test bench (1) includes a base plate (101), and anchor holes (102) are respectively opened at both ends of the base plate (101). The anchor holes (102) are threaded with precision rolled threaded steel bars (103). A steel lattice column (104) is welded to the upper end face of the base plate (101). A top plate (105) is fixedly connected to the upper end face of the steel lattice column (104). The top plate (105) is threadedly connected to the loading box component (5). Two flange plates (106) are respectively provided on the I-shaped branches on both sides of the steel lattice column (104). A vertical plate (107) is provided between the two flange plates (106). A stiffening plate (108) is fixedly installed on the outer side wall of the vertical plate (107) and the flange plate (106). The lower end face of the vertical plate (107) and the stiffening plate (108) is fixedly connected to the base plate (101).

5. The eccentric compression loading device for steel lattice columns according to claim 4, characterized in that: The loading box component (5) includes a support frame (501), which includes a longitudinal vertical plate. Two transverse vertical plates are symmetrically welded to both sides of the longitudinal vertical plate. Fixing plates (502) are welded to the upper end face, lower end face, left end face and right end face of the support frame (501). The fixing plate (502) on the lower end face is threadedly fixed to the top plate (105). An eccentric structure (10) is provided on the fixing plate (502) on the upper end face.

6. The eccentric compression loading device for steel lattice columns according to claim 4, characterized in that: The eccentric structure (10) includes two limiting steel bars (1001). The two limiting steel bars (1001) are fixedly installed in parallel on the fixing plate (502) on the upper end face of the support frame (501) and are set on one side of the fixing plate (502). A roller (1002) is provided on both limiting steel bars (1001). A baffle (1003) is welded to the upper end of the roller (1002). The upper end face of the baffle (1003) is fixedly connected to the hydraulic actuator (9) by bolts. An actuator cylinder (8) is fixedly installed on the upper end of the hydraulic actuator (9).

7. The eccentric compression loading device for steel lattice columns according to claim 1, characterized in that: The inner wall of the rectangular frame (601) is attached with a polytetrafluoroethylene sliding plate.

8. The eccentric compression loading device for steel lattice columns according to claim 1, characterized in that: The gap between the rectangular frame (601) and the fixing plate (502) is set to 2-4mm.

9. The eccentric compression loading device for steel lattice columns according to claim 1, characterized in that: A horizontal displacement meter is provided on each of the two end faces of the rectangular frame (601) away from the constraint component (3), and the horizontal displacement meter detects the horizontal displacement of the steel lattice column (104).

10. A steel lattice column eccentric compression loading device and a loading method thereof according to any one of claims 1-9, characterized in that: Step 1: Install and fix the test bench (1) to achieve bottom fixed end constraint. Weld the column base of the steel lattice column (104) to the base plate (101) and apply high-tonnage anchoring force with fine-rolled threaded steel (103) through the anchor holes (102) on both sides of the base plate (101) to fix the test bench (1) to the ground. This operation completely restricts all translation and rotation of the test bench (1) to form a fixed end constraint without displacement or rotation. Step 2: Assemble the eccentric structure (10) and the constraint component (3) to establish composite boundary conditions. Weld the roller (1002) to the baffle (1003) and connect it to the hydraulic actuator (9). Align the roller (1002) with the limiting steel bar (1001) placed on the top of the loading box component (5). At the same time, connect the steel sleeve structure (6) of the ring-shaped loading box component (5) to the constraint component (3) and fix it with turnbuckles (7). The eccentric structure (10) and the constraint component (3) allow vertical displacement and rotation around the axis at the top of the column, but effectively limit the X / Y displacement through horizontal constraints, forming a composite constraint. Step 3: Adjust the eccentricity and complete the loading centering. According to the target eccentricity, adjust the relative position of the hydraulic actuator (9) and the loading box component (5) so that the straight line where the lower quadrant point of the roller (1002) is located is aligned with the symmetrical center line between the two limit steel bars (1001). Use an external high-precision infrared level to check and ensure that the loading axis and the centroid of the column section maintain the set eccentricity to achieve precise centering. Step 4: Apply load and verify device reliability. Connect the external hydraulic control system and apply vertical eccentric pressure in stages according to the preset system. During the loading process, verify the effectiveness of the horizontal constraint by monitoring the horizontal displacement, and verify the hinge rotation performance by comparing the vertical displacement of the loaded side and the unloaded side. If the data meets the expectations, it indicates that the device is operating reliably and the boundary conditions have been successfully achieved.

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