Large stadium roof steel structure grading synchronous unloading device and construction method

Abstract

The application discloses a large stadium roof steel structure grading synchronous unloading device and a construction method, belongs to the technical field of steel structure building construction, and comprises a base, a hydraulic jack is fixedly arranged on one side of the upper end surface of the base, a height increasing frame is fixedly arranged on the other side of the upper end surface of the base, a plurality of cushion blocks are movably arranged at the center of the upper end surface of the height increasing frame, compensation assemblies are arranged at the two sides of the upper end surface of the height increasing frame, each compensation assembly comprises a top plate, a threaded rod is fixedly arranged at the lower end surface of each top plate, a threaded sleeve is threadedly connected to the center of the outer wall of each threaded rod, and a limiting ring is slidably connected to the upper end of the outer wall of each threaded rod; the application effectively avoids the sudden change of internal force of the structure in the unloading process, adopts the unloading node structure of the hydraulic jack and the cushion block group, accurately controls the descending amount, is simple and easy to operate, and is easy to implement the synchronous implementation of multiple unloading points.

Description

Technical Field

[0001] This invention relates to the field of steel structure building construction technology, and more specifically, to a graded synchronous unloading device and construction method for the steel structure of a large stadium roof. Background Technology

[0002] The construction method for the steel structure of the roof of a large stadium is usually to use a temporary support system, high-altitude assembly, and segmented hoisting. During the construction phase, the self-weight and construction load of the roof structure are all borne by the temporary lattice column support system set below it. After the main structure of the roof is installed and welded, the structural load needs to be transferred smoothly and safely from the temporary support system to the frame columns and seismic supports. This process is called unloading.

[0003] Existing unloading technologies have the following shortcomings: First, for composite roofs composed of multiple structural forms, the structural stiffness and support reaction forces vary significantly across different areas. Adopting a uniform unloading strategy—that is, simultaneously and equally lowering all support points—can lead to insufficient unloading in areas with high stiffness and excessive deformation or even instability in areas with low stiffness. Second, there is a lack of scientific division of unloading zones. Existing technologies typically treat all temporary supports as a single unit for unloading, without zoning based on structural stress characteristics and force transmission paths. This results in unclear load transfer paths during unloading, potentially leading to overloading of local members and nodes. Third, the determination of the unloading amount relies on experience. The total unloading height and graded descent of each support point are usually estimated by construction personnel based on experience, lacking precise calculations based on simulations of the entire construction process, posing safety hazards. Fourth, there is a lack of systematic design for differentiated unloading methods for different unloading zones. Using the same unloading method for the core area with large unloading deformation and the peripheral area with small unloading deformation will result in resource waste and safety risks.

[0004] Therefore, we have made improvements and proposed a graded synchronous unloading device and construction method for the steel structure of a large stadium roof. Summary of the Invention

[0005] In view of the above-mentioned problems existing in the prior art, the purpose of this invention is to provide a graded synchronous unloading device and construction method for the steel structure of a large stadium roof.

[0006] To solve the above problems, the technical solution adopted by the present invention is as follows: A graded synchronous unloading device for the steel structure of a large stadium roof includes a base. A hydraulic jack is fixedly installed on one side of the upper surface of the base, and a riser frame is fixedly installed on the other side of the upper surface of the base. Multiple pads are movably installed at the center of the upper surface of the riser frame. Compensation components are installed on both sides of the upper surface of the riser frame. Each compensation component includes a top plate. Threaded rods are fixedly installed on the lower surface of each of the two top plates. Threaded sleeves are threadedly sleeved at the center of the outer wall of each of the two threaded rods. Limit rings are slidably sleeved on the upper end of the outer wall of each of the two threaded rods. The riser frame... A limiting plate is fixedly installed near both ends of the upper end face. A limiting component is provided on one front end of one of the two limiting plates. The limiting component includes a hinge plate. A sliding rod is slidably installed through the upper center of the hinge plate. An insert is fixedly installed at one end of the sliding rod. A spring is movably sleeved on the other side of the outer wall of the sliding rod. A synchronization component is provided at the center of the lower end face of the heightening frame. The synchronization component includes a connecting shaft. Longitudinal bevel gears are fixedly sleeved at both ends of the outer wall of the connecting shaft. Transverse bevel gears are meshed with the outer walls of the two longitudinal bevel gears.

[0007] Preferably, the two limiting rings are fixedly disposed at the center of both sides of the upper end face of the riser, and the two threaded sleeves are rotatably disposed at the center of both sides of the lower end face of the riser, with a hexagonal sleeve fixedly sleeved at the lower end of the outer wall of each of the two threaded sleeves.

[0008] Preferably, protrusions are fixedly provided on both sides of the inner wall of the two limiting rings, and grooves are provided on both sides of the outer wall of the two threaded rods, with the protrusions slidingly embedded in the grooves respectively.

[0009] Preferably, the lower end of the hinge plate is rotatably disposed at the front end of one of the limiting plates, and a sleeve is movably disposed on the upper side of the hinge plate. One end of the sleeve is fixedly connected to the sliding rod, and both ends of the spring are fixedly connected to the sleeve and the hinge plate, respectively.

[0010] Preferably, each of the outer walls of the plurality of pads has a groove on its front end, and the pad is embedded in the uppermost groove among the plurality of grooves.

[0011] Preferably, a fixing sleeve is fixedly sleeved at the center of the outer wall of the connecting shaft, and the fixing sleeve is fixedly sleeved at the center of the lower end face of the outer wall of the riser. The two transverse bevel gears are respectively fixedly sleeved at the center of the outer wall of the two threaded sleeves.

[0012] Preferably, a protective outer shell is fixedly installed at the center of the lower end face of the heightening frame, and the two threaded sleeves respectively rotate through the center of the bottom end face of the outer wall of the protective outer shell.

[0013] Preferably, another limiting plate is movably provided with a pressure plate on the side near the pad, and a bolt is rotatably provided at the center of the outer wall of the pressure plate on the side away from the pad, and the bolt thread penetrates the limiting plate.

[0014] Preferably, each of the multiple pad blocks has a sliding groove on both sides of the upper end face of the outer wall, and each of the multiple pad blocks has a sliding strip fixedly installed on both sides of the lower end face of the outer wall, with the multiple sliding strips slidably installed inside the multiple sliding grooves.

[0015] The construction method for a graded synchronous unloading device for the steel structure of a large stadium roof includes the following steps: S1: Based on the differences in support conditions, structural stiffness, and unloading reaction forces in each area of ​​the roof, the entire temporary lattice column support system is divided into a first unloading area and a second unloading area; wherein, the first unloading area includes a first type of support group located below the inner ring truss and a second type of support group located below the radial arch truss, and the second unloading area includes a third type of support group located below the outer ring truss and the eaves truss; the total unloading height of all support points in the first unloading area is greater than the total unloading height of all support points in the second unloading area; S2: Number and group all support points in the first unloading area, and assign support points that are symmetrical about the center of the roof plane and have similar total unloading heights to the same control group; install an unloading node device at each support point, the unloading node device includes a hydraulic jack set between the top surface of the temporary support and the bottom surface of the roof structure and a group of removable pads composed of multiple layers of steel plates; connect all hydraulic jacks to the computer synchronous control system through oil pipes; S3: Based on the peak unloading reaction force and unloading displacement of each support point obtained from the simulation calculation of the entire construction process, a total unloading height and graded unloading step length are set for each support point; support points with a total unloading height greater than the first preset value are divided into four levels of unloading, and support points with a total unloading height less than or equal to the first preset value are divided into three levels and two levels of unloading; in the same level of unloading, the current level descent of each support point is determined by its total unloading height according to a preset ratio; S4: Start the first stage of unloading: The computer synchronous control system controls all hydraulic jacks to lift synchronously, so that the bottom surface of the roof structure is separated from the top surface of the pad block group at each support point; the construction personnel simultaneously remove the first layer of steel plate pad block of the corresponding thickness at each support point; then the computer synchronous control system controls all hydraulic jacks to lower synchronously, so that the roof structure is smoothly placed on the lowered pad block group, completing the first stage of unloading. S5: Repeat step S4, descending step by step according to the preset second, third and fourth unloading step sizes, until the cumulative descent of each support point reaches its preset total unloading height, and the unloading of the first unloading area is completed. S6: During and after each unloading stage, sensors deployed at each support point and on key members of the roof structure acquire structural response data in real time; when any monitoring data exceeds the preset warning value, unloading is paused and the abnormality is eliminated before continuing. S7: After the first unloading area is unloaded, the second unloading area is unloaded; the unloading of the second unloading area adopts the method of multi-point synchronous flame cutting of the lattice column of the third type of support group, so that the load of the outer ring truss and the eaves truss is gradually transferred to the permanent frame column below it. S8: After all unloading is completed and the structure is confirmed to be stable, remove all temporary lattice column support systems.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Based on the stiffness differences and unloading reaction force distribution in different structural regions, the temporary support system is divided into two unloading zones. Two different unloading methods, computer-synchronized graded unloading and flame cutting unloading, are adopted respectively. This fully adapts to the characteristic differences of different regions during the force system transformation process. The total unloading height, graded step length, and jack tonnage of each support point are determined based on the simulation calculation results of the entire construction process, realizing the precise preset of unloading parameters and avoiding the blindness and safety risks of experience-based decision-making. The first unloading zone adopts computer-controlled hydraulic synchronous graded unloading. Each support point descends synchronously according to the preset step length. With structural deformation and internal force control as the core and smooth transition as the goal, it effectively avoids sudden changes in structural internal forces during the unloading process. Through dual real-time monitoring of displacement and stress, the structural response can be obtained in real time during each unloading stage. When the deviation exceeds the limit, unloading is paused and timely adjustments are made to ensure that the entire unloading process is safe and controllable. The unloading node structure using hydraulic jacks and pad blocks has precise control over the descent amount, is easy to operate, and is easy to implement simultaneously at multiple unloading points.

[0017] 2. The compensation component at the upper end of the riser can flexibly adjust the height of the top plate through the relative rotation of the threaded rod and the threaded sleeve, so as to achieve the effect of support height compensation and avoid the phenomenon that the removed pads are too short or too high. The insert of the limiting component is embedded in the groove of the pad under the action of the spring to prevent the upper pad from sliding. It can prevent the pads from sliding back and forth and prevent the lower pads from being misaligned when the upper pad is removed, thus avoiding affecting the support effect. Attached Figure Description

[0018] Figure 1 A schematic diagram of the overall right front axonometric projection of the graded synchronous unloading device for the steel structure roof of a large stadium provided in this application; Figure 2 A schematic diagram of the overall left front axonometric projection of the graded synchronous unloading device for the steel structure roof of a large stadium provided in this application; Figure 3A schematic diagram of the internal structure of the protective shell of the graded synchronous unloading device for the steel structure roof of a large stadium provided in this application; Figure 4 A schematic diagram of the compensation component assembly for the graded synchronous unloading device for the steel structure roof of a large stadium provided in this application; Figure 5 A schematic diagram of the limit component assembly for the graded synchronous unloading device for the steel structure roof of a large stadium provided in this application.

[0019] In the diagram: 1. Base; 2. Hydraulic jack; 3. Elevator frame; 4. Protective shell; 5. Compensation component; 6. Limiting plate; 7. Pressure plate; 8. Pad; 9. Limiting component; 10. Slide groove; 11. Slide bar; 12. Synchronization component; 13. Insert groove; 501. Top plate; 502. Limiting ring; 503. Threaded sleeve; 504. Hexagonal sleeve; 505. Threaded rod; 901. Hinge plate; 902. Insert; 903. Sleeve; 904. Sliding rod; 905. Spring; 1201. Transverse bevel gear; 1202. Connecting shaft; 1203. Fixed sleeve plate; 1204. Longitudinal bevel gear. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0021] A graded synchronous unloading device for the steel structure of a large stadium roof includes a base 1. A hydraulic jack 2 is fixedly installed on one side of the upper surface of the base 1, and a riser frame 3 is fixedly installed on the other side of the upper surface of the base 1. Multiple pads 8 are movably installed at the center of the upper surface of the riser frame 3. Compensation components 5 are installed on both sides of the upper surface of the riser frame 3. Each compensation component 5 includes a top plate 501. Threaded rods 505 are fixedly installed on the lower surface of each of the two top plates 501. Threaded sleeves 503 are threadedly sleeved at the center of the outer wall of each of the two threaded rods 505. Limit rings 502 are slidably sleeved at the upper end of the outer wall of each of the two threaded rods 505. The center of the upper surface of the riser frame 3 is located near both ends. Each of the two limiting plates 6 is fixedly installed. One of the limiting plates 6 has a limiting component 9 at one front end. The limiting component 9 includes a hinge plate 901. A sliding rod 904 is slidably installed through the center of the upper end of the hinge plate 901. An insert 902 is fixedly installed at one end of the sliding rod 904. A spring 905 is movably sleeved on the other side of the outer wall of the sliding rod 904. A synchronization component 12 is installed at the center of the lower end face of the heightening frame 3. The synchronization component 12 includes a connecting shaft 1202. Both ends of the outer wall of the connecting shaft 1202 are fixedly sleeved with longitudinal bevel gears 1204. The outer walls of the two longitudinal bevel gears 1204 are meshed with transverse bevel gears 1201.

[0022] The base 1 is fixed to the construction foundation. The output end of the hydraulic jack 2 lifts the bottom surface of the roof structure, pushing it to rise as a whole. The compensation component 5 at the upper end of the heightening frame 3 adjusts the height of the top plate 501 through the relative rotation of the threaded rod 505 and the threaded sleeve 503, avoiding the phenomenon that the extra pad 8 is too short and the less pad 8 is too high. The insert 902 of the limiting component 9 is embedded into the groove 13 of the pad 8 under the action of the spring 905, preventing the upper pad 8 from sliding. The synchronization component 12 drives the transverse bevel gears 1201 on both sides to rotate synchronously through the connecting shaft 1202, ensuring the consistency of the adjustment of the left and right compensation components 5.

[0023] Furthermore, two limiting rings 502 are fixedly installed at the center of both sides of the upper end face of the riser 3, and two threaded sleeves 503 are rotatably installed at the center of both sides of the lower end face of the riser 3. A hexagonal sleeve 504 is fixedly sleeved at the lower end of the outer wall of each of the two threaded sleeves 503.

[0024] The limiting ring 502 is fixed to the upper end face of the riser 3. Its inner wall protrusion is embedded in the groove of the outer wall of the threaded rod 505, which restricts the threaded rod 505 to move only axially and cannot rotate. The threaded sleeve 503 is rotatably set at the lower end of the riser 3. Through the cooperation of the hexagonal sleeve 504 and the external wrench, the threaded rod 505 is driven to move up and down to adjust the height of the top plate 501.

[0025] Furthermore, protrusions are fixedly provided on both sides of the inner wall of the two limiting rings 502, and grooves are provided on both sides of the outer wall of the two threaded rods 505, with multiple protrusions slidingly embedded in multiple grooves respectively.

[0026] Furthermore, the lower end of the hinge plate 901 is rotatably mounted on the front end of one of the limiting plates 6, and a sleeve 903 is movably mounted on one side of the upper end of the hinge plate 901. One end of the sleeve 903 is fixedly connected to the sliding rod 904, and both ends of the spring 905 are fixedly connected to the sleeve 903 and the hinge plate 901, respectively. The lower end of the hinge plate 901 is rotatably connected to the limiting plate 6, and the upper end is fixed to the sliding rod 904 through the sleeve 903. The spring 905 is sleeved on the outer wall of the sliding rod 904, and the two ends abut against the sleeve 903 and the hinge plate 901 respectively. When the pad blocks 8 are stacked in place, the spring 905 pushes the sliding rod 904 forward, so that the insert 902 is embedded in the groove 13 of the pad block 8 to achieve locking. This can prevent the lower pad blocks 8 from being misaligned and affecting the support effect when the upper pad block 8 is pulled out.

[0027] Furthermore, each of the outer walls of the multiple pads 8 has a groove 13 at its front end, and the pad 902 is embedded in the uppermost groove 13 among the multiple grooves 13.

[0028] Furthermore, a fixing sleeve 1203 is fixedly sleeved at the center of the outer wall of the connecting shaft 1202. The fixing sleeve 1203 is fixedly installed at the center of the lower end face of the outer wall of the heightening frame 3. Two transverse bevel gears 1201 are respectively fixedly sleeved at the center of the outer wall of two threaded sleeves 503.

[0029] The connecting shaft 1202 is fixed to the lower end of the riser 3 by the fixing sleeve 1203. The longitudinal bevel gears 1204 at both ends of the shaft mesh with the transverse bevel gears 1201 on both sides respectively. When one of the threaded sleeves 503 is rotated, it will drive the transverse bevel gear 1201 on its outer wall to rotate, and then drive the connecting shaft 1202 to rotate through the longitudinal bevel gear 1204 meshing with it, thereby driving the transverse bevel gears 1201 on both sides to rotate synchronously, and thus driving the two threaded sleeves 503 to rotate at the same speed.

[0030] Furthermore, a protective shell 4 is fixedly installed at the center of the lower end face of the riser 3, and two threaded sleeves 503 respectively rotate through the center of the bottom end face of the outer wall of the protective shell 4.

[0031] Furthermore, a pressure plate 7 is movably provided on the side of another limiting plate 6 near the pad 8, and a bolt is rotatably provided at the center of the outer wall of the pressure plate 7 on the side away from the pad 8, with the bolt thread penetrating the limiting plate 6.

[0032] The pressure plate 7 is rotatably connected to the limiting plate 6 by bolts. When the bolts are tightened, the pressure plate 7 moves to one side of the pad 8 and presses against its side wall, thus restricting the lateral displacement of the pad 8.

[0033] Furthermore, multiple pad blocks 8 have sliding grooves 10 on both sides of the upper end face of the outer wall, and multiple pad blocks 8 have sliding strips 11 fixedly installed on both sides of the lower end face of the outer wall, with the multiple sliding strips 11 slidingly installed inside the multiple sliding grooves 10 respectively.

[0034] The slider 11 on the lower end face of the pad 8 slides into the groove 10 on the upper end face of the lower pad 8 to form a stacking guide structure. Multiple pads 8 are stacked sequentially through the cooperation of the slider 11 and the groove 10 to achieve height accumulation.

[0035] The construction method for a graded synchronous unloading device for the steel structure of a large stadium roof includes the following steps: S1: Based on the differences in support conditions, structural stiffness, and unloading reaction forces in each area of ​​the roof, the entire temporary lattice column support system is divided into a first unloading area and a second unloading area; wherein, the first unloading area includes a first type of support group located below the inner ring truss and a second type of support group located below the radial arch truss, and the second unloading area includes a third type of support group located below the outer ring truss and the eaves truss; the total unloading height of all support points in the first unloading area is greater than the total unloading height of all support points in the second unloading area; S2: Number and group all support points in the first unloading area, and assign support points that are symmetrical about the center of the roof plane and have similar total unloading heights to the same control group; install an unloading node device at each support point, the unloading node device includes hydraulic jacks 2 set between the top surface of the temporary support and the bottom surface of the roof structure and 8 sets of removable pads composed of multiple layers of steel plates; connect all hydraulic jacks 2 to the computer synchronous control system through oil pipes; S3: Based on the peak unloading reaction force and unloading displacement of each support point obtained from the simulation calculation of the entire construction process, a total unloading height and graded unloading step length are set for each support point; support points with a total unloading height greater than the first preset value are divided into four levels of unloading, and support points with a total unloading height less than or equal to the first preset value are divided into three levels and two levels of unloading; in the same level of unloading, the current level descent of each support point is determined by its total unloading height according to a preset ratio; S4: Start the first stage of unloading: The computer synchronous control system controls all hydraulic jacks 2 to lift synchronously, so that the bottom surface of the roof structure is separated from the top surface of the pad blocks 8 at each support point; the construction personnel simultaneously remove the first layer of steel plate pad blocks 8 of the corresponding thickness at each support point; then the computer synchronous control system controls all hydraulic jacks 2 to lower synchronously, so that the roof structure is smoothly placed on the lowered pad blocks 8, completing the first stage of unloading. S5: Repeat step S4, descending step by step according to the preset second, third and fourth unloading step sizes, until the cumulative descent of each support point reaches its preset total unloading height, and the unloading of the first unloading area is completed. S6: During and after each unloading stage, sensors deployed at each support point and on key members of the roof structure acquire structural response data in real time; when any monitoring data exceeds the preset warning value, unloading is paused and the abnormality is eliminated before continuing. S7: After the first unloading area is unloaded, the second unloading area is unloaded; the unloading of the second unloading area adopts the method of multi-point synchronous flame cutting of the lattice column of the third type of support group, so that the load of the outer ring truss and the eaves truss is gradually transferred to the permanent frame column below it. S8: After all unloading is completed and the structure is confirmed to be stable, remove all temporary lattice column support systems.

[0036] Further, in step S1, the unloading sequence of the first unloading area precedes that of the second unloading area; the total unloading height of the first unloading area is on the order of several hundred millimeters, and the total unloading height of the second unloading area is on the order of millimeters. In step S2, the tonnage of the hydraulic jack is determined based on the peak value of the unloading reaction force at its support point; support points with a peak unloading reaction force greater than a preset reaction force threshold use a first-tonnage jack, and support points with a peak unloading reaction force less than or equal to the preset reaction force threshold use a second-tonnage jack, with the first-tonnage jack being greater than the second-tonnage jack. In step S3, the preset proportional allocation method is as follows: for support points with four levels of unloading, the first-level unloading amount is 25% of the total unloading height, the second-level unloading amount is 25% of the total unloading height, the third-level unloading amount is 25% of the total unloading height, the fourth-level unloading amount is 25% of the total unloading height, the fifth-level unloading amount is 25% of the total unloading height, the sixth ... The unloading amounts for the second, third, and fourth stages are all 25% of the total unloading height; for the support points of the third-stage unloading, the unloading amount for each stage is one-third of the total unloading height. In step S6, the sensors include displacement sensors and stress sensors; the displacement sensors are plumb bobs and vertical steel rulers hung at each support point; the stress sensors are vibrating wire strain sensors pre-welded to the surface of key members of the roof structure. In step S7, the sequence of multi-point synchronous flame cutting is as follows: starting from the circumferential middle position of the second unloading area, proceeding symmetrically to both sides, cutting the lattice column columns at symmetrical positions each time. In step S4, the height of synchronous lifting of the hydraulic jacks is 10 to 15 millimeters.

[0037] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of protection of this application is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of one or more embodiments of this application as described above, which are not provided in detail for the sake of brevity.

[0038] One or more embodiments in this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments in this application should be included within the protection scope of this application.

Claims

1. A graded synchronous unloading device for the steel structure of a large stadium roof, characterized in that, The system includes a base (1), a hydraulic jack (2) fixedly mounted on one side of the upper surface of the base (1), a booster frame (3) fixedly mounted on the other side of the upper surface of the base (1), a plurality of pads (8) movably mounted at the center of the upper surface of the booster frame (3), compensation components (5) mounted on both sides of the upper surface of the booster frame (3), each of the two compensation components (5) including a top plate (501), a threaded rod (505) fixedly mounted on the lower surface of each of the two top plates (501), a threaded sleeve (503) threadedly sleeved at the center of the outer wall of each of the two threaded rods (505), a limit ring (502) slidably sleeved at the upper end of the outer wall of each of the two threaded rods (505), and a limit plate (6) fixedly mounted near both ends at the center of the upper surface of the booster frame (3). One of the two limiting plates (6) has a limiting component (9) at one end of its side. The limiting component (9) includes a hinge plate (901). A sliding rod (904) is slidably provided through the center of the upper end of the hinge plate (901). An insert (902) is fixedly provided at one end of the sliding rod (904). A spring (905) is movably sleeved on the other side of the outer wall of the sliding rod (904). A synchronization component (12) is provided at the center of the lower end face of the heightening frame (3). The synchronization component (12) includes a connecting shaft (1202). Both ends of the outer wall of the connecting shaft (1202) are fixedly sleeved with longitudinal bevel gears (1204). The outer walls of the two longitudinal bevel gears (1204) are meshed with transverse bevel gears (1201).

2. The staged synchronous unloading device for the steel structure of a large stadium roof according to claim 1, characterized in that, The two limiting rings (502) are fixedly installed at the center of both sides of the upper end face of the riser (3), and the two threaded sleeves (503) are rotatably installed at the center of both sides of the lower end face of the riser (3). A hexagonal sleeve (504) is fixedly sleeved at the lower end of the outer wall of each of the two threaded sleeves (503).

3. The staged synchronous unloading device for the steel structure of a large stadium roof according to claim 1, characterized in that, Both sides of the inner wall of the two limiting rings (502) are fixedly provided with protrusions, and both sides of the outer wall of the two threaded rods (505) are provided with grooves. The protrusions are slidably embedded in the grooves respectively.

4. The staged synchronous unloading device for the steel structure of a large stadium roof according to claim 1, characterized in that, The lower end of the hinge plate (901) is rotatably disposed on the front end of one of the limiting plates (6). A sleeve (903) is movably disposed on one side of the upper end of the hinge plate (901). One end of the sleeve (903) is fixedly connected to the sliding rod (904). Both ends of the spring (905) are fixedly connected to the sleeve (903) and the hinge plate (901) respectively.

5. The staged synchronous unloading device for the steel structure of a large stadium roof according to claim 1, characterized in that, Each of the multiple pads (8) has a groove (13) on one front end of its outer wall. The pad (902) is embedded in the uppermost groove (13) among the multiple grooves (13).

6. The staged synchronous unloading device for the steel structure of a large stadium roof according to claim 1, characterized in that, A fixing sleeve plate (1203) is fixedly sleeved at the center of the outer wall of the connecting shaft (1202). The fixing sleeve plate (1203) is fixedly sleeved at the center of the lower end face of the outer wall of the heightening frame (3). The two transverse bevel gears (1201) are respectively fixedly sleeved at the center of the outer wall of the two threaded sleeves (503).

7. The staged synchronous unloading device for the steel structure of a large stadium roof according to claim 1, characterized in that, A protective shell (4) is fixedly installed at the center of the lower end face of the height-increasing frame (3), and the two threaded sleeves (503) respectively rotate through the center of the bottom end face of the outer wall of the protective shell (4).

8. The staged synchronous unloading device for the steel structure of a large stadium roof according to claim 1, characterized in that, Another limiting plate (6) is movably provided with a pressure plate (7) on the side near the pad (8). A bolt is rotatably provided at the center of the outer wall of the pressure plate (7) away from the pad (8), and the bolt thread passes through the limiting plate (6).

9. The staged synchronous unloading device for the steel structure of a large stadium roof according to claim 1, characterized in that, Each of the multiple pads (8) has a sliding groove (10) on both sides of the upper end face of the outer wall, and a sliding strip (11) is fixedly provided on both sides of the lower end face of the outer wall of the multiple pads (8). The multiple sliding strips (11) are respectively slidably disposed inside the multiple sliding grooves (10).

10. A construction method for a graded synchronous unloading device for the steel structure of a large stadium roof, comprising the graded synchronous unloading device for the steel structure of a large stadium roof as described in any one of claims 1-9, characterized in that... Specifically, the following steps are included: S1: Based on the differences in support conditions, structural stiffness, and unloading reaction forces in each area of ​​the roof, the entire temporary lattice column support system is divided into a first unloading area and a second unloading area; wherein, the first unloading area includes a first type of support group located below the inner ring truss and a second type of support group located below the radial arch truss, and the second unloading area includes a third type of support group located below the outer ring truss and the eaves truss; the total unloading height of all support points in the first unloading area is greater than the total unloading height of all support points in the second unloading area; S2: Number and group all support points in the first unloading area, and assign support points that are symmetrical about the center of the roof plane and have similar total unloading heights to the same control group; install an unloading node device at each support point, the unloading node device includes a hydraulic jack set between the top surface of the temporary support and the bottom surface of the roof structure and a group of removable pads (8) composed of multiple layers of steel plates; connect all hydraulic jacks (2) to the computer synchronous control system through oil pipes; S3: Based on the peak unloading reaction force and unloading displacement of each support point obtained from the simulation calculation of the entire construction process, a total unloading height and graded unloading step length are set for each support point; support points with a total unloading height greater than the first preset value are divided into four levels of unloading, and support points with a total unloading height less than or equal to the first preset value are divided into three levels and two levels of unloading; in the same level of unloading, the current level descent of each support point is determined by its total unloading height according to a preset ratio; S4: Start the first stage of unloading: The computer synchronous control system controls all hydraulic jacks (2) to lift synchronously, so that the bottom surface of the roof structure is separated from the top surface of the pads (8) at each support point; the construction personnel simultaneously remove the first layer of steel plate pads (8) of the corresponding thickness at each support point; then the computer synchronous control system controls all hydraulic jacks (2) to lower synchronously, so that the roof structure is smoothly placed on the lowered pads (8) to complete the first stage of unloading; S5: Repeat step S4, descending step by step according to the preset second, third and fourth unloading step sizes, until the cumulative descent of each support point reaches its preset total unloading height, and the unloading of the first unloading area is completed. S6: During and after each unloading stage, sensors deployed at each support point and on key members of the roof structure acquire structural response data in real time; when any monitoring data exceeds the preset warning value, unloading is paused and the abnormality is eliminated before continuing. S7: After the first unloading area is unloaded, the second unloading area is unloaded; the unloading of the second unloading area adopts the method of multi-point synchronous flame cutting of the lattice column of the third type of support group, so that the load of the outer ring truss and the eaves truss is gradually transferred to the permanent frame column below it. S8: After all unloading is completed and the structure is confirmed to be stable, remove all temporary lattice column support systems.

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