Large-span steel structure grid roof construction method based on ground assembly and dynamic controllable jacking

Abstract

The invention discloses a large-span steel structure grid roof construction method based on ground assembly and dynamic controllable jacking, and relates to the technical field of steel structure roofs. The large-span steel structure grid roof construction method comprises the following steps that S1, a foundation and a supporting system are constructed; s2, ground low-altitude assembly and preparation, wherein finished rod pieces and welding balls enter a field, field inspection is conducted, a temporary supporting system is arranged, a core net rack ground overall assembly strategy is conducted, the assembly process is conducted, external expansion assembly precision control is conducted, and main structure installation and preliminary protection are conducted; s3, synchronous jacking and system conversion are carried out; and S4, high-altitude inlaying and system forming are carried out. The core of the method is that an overall technical route of ground integral assembly, numerical control synchronous jacking and high-altitude inlaying and closing is adopted, so that the traditional technical defects of high risk of high-altitude operation, difficulty in precision control, strong dependence on large hoisting equipment and the like are overcome.

Description

Technical Field

[0001] This invention relates to the field of steel structure roofing technology, and more specifically to the field of construction methods for large-span steel structure space frame roofs based on ground assembly and dynamic controllable jacking. Background Technology

[0002] With the increasing demand for large-span spaces in modern industrial and public buildings, steel structure space frame roofs are widely used in stadiums, exhibition centers, industrial plants, and other buildings due to their advantages such as lightweight structure, high strength, and short construction period. However, traditional large-span space frame installations often employ high-altitude assembly or overall hoisting methods, which suffer from problems such as long construction periods, high safety risks, difficulty in precision control, and heavy reliance on lifting equipment. Especially under complex site conditions or existing structural constraints, the following drawbacks exist: For the high-altitude bulk loading method: it requires the erection of full-span scaffolding, which is time-consuming and material-intensive. In addition, the amount of high-altitude work is large, measurement and correction are difficult, cumulative errors are easy to occur, and safety risks are high.

[0003] For the overall hoisting / lifting method: it requires extremely high performance from the lifting machinery and is suitable for projects with open, unobstructed sites. It is difficult to implement in complex factory buildings or when there are auxiliary structures nearby. Furthermore, the internal forces of the overall structure change complexly during hoisting, and improper control can easily lead to deformation of the members.

[0004] For the segmented hoisting and high-altitude docking method: there are many segmented interfaces, it is difficult to guarantee the accuracy of high-altitude docking, the welding quality is greatly affected by environmental factors, and there is a lot of high-altitude work involved. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned technical problems by providing a construction method for large-span steel structure space frame roofs based on ground assembly and dynamic controllable jacking.

[0006] To achieve the above objectives, the present invention specifically adopts the following technical solution: This invention provides a construction method for large-span steel space frame roofs based on ground assembly and dynamic controllable jacking, comprising the following steps: S1. Construction of foundation and support system; S2. Ground low-altitude assembly and preparation: finished poles and welded balls arrive on site → on-site inspection → setting up a temporary support system → core space frame ground overall assembly strategy → assembly process → precision control of outward assembly → main structure installation and preliminary protection; S3, Synchronous Lifting and System Conversion; S4, High-altitude patching and system forming.

[0007] In one implementation, the specific steps of step S1 are as follows: S11. Precise pre-embedding and foundation construction: During the assembly process, the installed and inspected nodes are used as stable benchmarks, and the theoretical length of the subsequent members to be installed is used as rigid constraints to deduce and lock the spatial position of the new nodes in reverse. This method decomposes the global error into multiple local geometrically invariant systems, so that the error is absorbed and digested during the transmission process. S12. Support installation and fixing: Tower crane and truck crane work together to hoist the welded ball support to the design elevation of the top of the concrete column. After fine adjustment with total station and level, the upper support and the pre-embedded anchor bolt base are fixed firmly with electric arc welding (E43 welding rod) to form a permanent support point for the space frame.

[0008] Specifically, in addition to considering the relatively large load on the steel space frame and the possible deviation and error in the pre-embedded supports, stiffening plates are added to the conventional steel space frame supports to enhance their bearing capacity, and the anchor bolt holes are set as strip-shaped adjustable holes to achieve the function of adjusting the error.

[0009] In one implementation, the specific steps of precise pre-embedding and foundation construction in step S11 are as follows: After each grid cell is assembled, a total station is used to remeasure the three-dimensional coordinates and compare the data with the BIM model. Any minor deviations will be actively corrected in the next grid cell assembly by fine-tuning the connection positions of the members (using bolt ball gaps or weld bevels). A total station was used for high-precision positioning and layout to ensure the position of the column top anchor bolts and the jacking frame foundation. The jacking frame foundation (2000mm×2000mm) is made of reinforced concrete. The pre-embedded anchor bolts are positioned by a special fixing frame, and the verticality deviation is controlled within 1 / 1000. This is the basis for the accuracy of the entire installation process.

[0010] In one implementation, step S2 specifically includes the following: S21. Set up a temporary support system: Based on the design projection position of the lower chord ball of the space frame, set up a temporary support system on the ground with a certain strength (high-strength plastic, wooden blocks, brick blocks, etc.) as a temporary support. The top elevation deviation of the temporary support system is controlled within ±2mm to provide a flat and stable reference surface for ground assembly. S22. Core space frame ground assembly strategy: Strictly follow the assembly sequence of "from the center to the surroundings" and "lower chord → web members → upper chord", and gradually expand outwards based on small units (such as quadrilateral grids); S23. Assembly process: S24. Precision control of external expansion assembly: Using a total station for real-time tracking measurement, the three-dimensional spatial position of the next ball node is accurately determined by controlling the length of the three rods connected to the same welded ball, thereby effectively eliminating accumulated errors and achieving precision control. S25. Main Structure Installation and Preliminary Protection: Install the main purlins (120×80×4mm) on the upper chord of the core space frame assembled on the ground and spray fireproof coating to the design thickness (≥2.5mm). This ground-based approach to high-altitude work reduces the risks of high-altitude operations and improves installation efficiency and safety.

[0011] Specifically, the node connection method in the assembly process is as follows: high-strength bolts (such as M16 bolts, torque 100-120 N·m) or CO2 gas shielded welding (ER50-X welding wire) are used for connection to ensure node strength; In addition, the specific assembly process of the starting frame is as follows: First, install the grid frame with two grids in the center to form a small whole. On the ground, use temporary support points (240*240mm brick stacks or pads) to support the nine lower chord balls and connect the lower chord rods of these nine lower chord balls. Then, using the mutual positioning between the balls and rods, use two web rods to make an A-shape to install the upper chord balls of the second layer to form an integral structure. Based on the ball nodes in the drawings, determine the Z-coordinate and height difference of the lower chord ball. Then, according to the size of the sphere to be assembled in the central area, place brick stacks on the ground. Measure the central cross lines on each brick stack. Use steel pipe positioning rings to determine the position of the ball nodes and connect the members between the assembly nodes to form a lower chord quadrilateral unit grid. Then, use three web members to position the upper chord center ball, ensuring that the center of the upper chord ball matches the center of the ground projection. Connect the other two members to form a small unit reference control point. When assembling the space frame in each area, assemble it according to the assembly sequence of "lower chord - web member - upper chord" and "middle - both ends (span direction) - both ends (non-span direction)".

[0012] When placing the steel balls, make sure you know their specifications and numbers to avoid discrepancies between the numbers and the actual balls, which could cause unnecessary downtime or rework. When assembling, first fix the lower chord members and the welded balls together to form a square frame. Then, use a steel ruler and level to check the geometric dimensions of the space frame. Only after confirming that everything is correct can you continue assembling the lower grid space frame.

[0013] While assembling the lower chord grid, "V" shapes can be spot-welded on the ground. After installing the upper chord, install the "V" shapes, and then install the upper chord members of the space frame. After installing one grid, use a steel ruler to re-measure the geometric dimensions. If there are no errors, continue assembling the next grid in the same way until the space frame is assembled.

[0014] In addition, the precision control principle of the external expansion assembly is as follows: Since the core grid structure adopts the ground assembly method, after the small assembly unit is assembled and its installation accuracy is checked and qualified, the length of the three rods connected to the same welding ball is used as the control index to perform the spatial positioning of the next welding ball. As the area of ​​the assembled units changes continuously during the expansion process, the already assembled structure will undergo some overall elastic deformation due to the unchanged position of the lifting points. However, since the relative stiffness of each small unit is relatively large, the space frame will not deform locally. Therefore, during the expansion, the length of the rods is used as a positioning reference corresponding to the three other welded balls that have been installed, which will not cause cumulative errors to the overall space frame. During the assembly process, the cutting length of the space frame rods needs to be strictly controlled, and the influence of bolt gaps on the cutting length should be fully considered. After a portion of the small units is assembled, the coordinates of the corresponding positions should be converted in AutoCAD software using the 3D model of the space frame. The installation accuracy of the assembled small units should be checked using the converted relative coordinate positions. If deviations occur, adjustments should be made in the next small unit.

[0015] In one implementation, the specific method of step S23 is as follows: S231, Ground assembly and layout of the core space frame; S232. Place positioning brick stacks or pads; S233, Place the first layer of four welded balls; S234. Assemble the first layer of lower chord; S235, Assemble the second layer of topspin ball and diagonal brace; S236. After the central area is assembled, the assembly is gradually expanded outwards by using the mutual positioning between the ball and the stick until the core net frame is assembled.

[0016] In one implementation, the specific process of synchronous lifting and system conversion in step S3 is as follows: S31. Installation and commissioning of the jacking system: Install jacking brackets composed of standard sections at the 8 preset jacking points, install the support plates on the top of the grid frame that match the upper chord ball, connect the hydraulic jacks (rated thrust 600kN) and the PLC synchronous control system, and conduct a trial jacking (jacking 100mm and then suspending for 24 hours) to check the system synchronization (deviation ≤2mm) and structural safety. S32, CNC synchronous lifting and dynamic stabilization: S321. High-precision synchronous lifting control system: This system integrates a programmable logic controller (PLC), a hydraulic servo / proportional system, and high-precision sensors to achieve high-precision synchronous lifting control. It includes the following components: S3211, System Hardware Configuration Execution unit: Multiple large-tonnage hydraulic jacks (such as D160 / 100-1265 type, rated thrust 600kN) arranged in an array. Each jack is an independent control node. Considering the large tonnage, anti-tipping supports are set for the lifting support to ensure the stability and safety of the lifting jacks. Sensing Unit: Each jack piston rod end integrates a high-precision magnetostrictive displacement sensor (accuracy ±0.01%FS) to provide real-time feedback on piston rod stroke; a pressure sensor is installed at the jack oil circuit inlet to monitor load changes in real time; total station prisms or GNSS receivers are arranged on the top of the lifting frame and key nodes of the grid structure to form a spatial configuration monitoring system. Control unit: The core is an industrial-grade PLC, equipped with a high-speed analog input / output module for acquiring sensor signals and controlling valves, and an industrial real-time Ethernet module for high-speed communication within the system; Drive unit: The core control element of the hydraulic system is an electro-hydraulic proportional valve or servo valve. It has fast response speed and good control linearity. It can receive analog signals (such as 0-10V DC) sent by PLC and accurately and proportionally control the flow and direction of hydraulic oil. S3212. Synchronization Control Strategy and Algorithm: The system adopts a multi-mode intelligent synchronization control algorithm that combines "master-slave setting and average deviation correction", including the following modes: Master-slave setting mode: During the normal uniform lifting phase, a lifting point located in a region with high structural stiffness is designated as the master point, and the remaining points are slave points. The system controls all slave points to strictly follow the displacement-time curve of the master point. Average Deviation Correction Mode: The system calculates the average displacement of all lifting points in real time and compares the real-time displacement of each lifting point with the average displacement. When the deviation of any lifting point from the average displacement exceeds a first set threshold (e.g., ±2mm), the PLC outputs a fine-tuning command to the proportional valve at that point. This slightly depressurizes and slows down leading points, and slightly increases pressure and accelerates lagging points, achieving a "peak shaving and valley filling" style of coordinated deviation correction. Safety interlock: The system is equipped with a three-level alarm mechanism. When the deviation exceeds ±5mm, an audible and visual warning is issued; when it exceeds ±8mm, the system automatically reduces speed; when it exceeds the limit value of ±10mm, the system immediately enters emergency stop mode, all proportional valves close, and the hydraulic system locks to ensure structural safety. S322, “Lifting-Reaching” Cyclic Climbing Operation Process; S323. Active dynamic stabilization system: In view of the characteristic that the stiffness of the continuously rising jacking support decreases with the increase of height, the present invention designs an active dynamic stabilization system that can adaptively adjust with the height. In step S33, the structure and process of the high-precision synchronous lifting control system.

[0017] In one implementation, the "lifting-reaching" cyclic climbing operation process in step S322 is as follows: This process is the core of achieving the "self-growth" of the lifting frame, and its meticulous management is key to safety. Each cycle follows the standardized procedures below: S3221. System self-check and confirmation before lifting: The PLC automatically executes the system checklist, including: the communication status of all sensors, hydraulic system pressure, valve function, and initial height difference of each point. The system is only allowed to start lifting after the operator confirms "everything is normal" on the HMI interface. S3222, Synchronous Lifting Stage: When the operator issues the lifting command, the system lifts the entire space frame by one standard section height (920mm) according to the preset S-shaped speed curve (acceleration in the initial section, constant speed in the middle section, and deceleration in the final section to reduce hydraulic shock and structural dynamic load). The lifting speed is controlled at ≤5mm / min. S3223, Hydraulic Locking and Hovering Monitoring: After the jacking is in place, the PLC controls all proportional valves to return to the neutral position and triggers the hydraulic locking device to make the grid frame hover stably at the design height. The system enters the hovering monitoring mode and continuously monitors the pressure and displacement of each point for at least 30 minutes to confirm that there is no abnormal settlement or drift. S3224, Support Height and Stability Enhancement: Under hydraulic locking and absolute structural stability, workers add standard sections and, based on the current lifting height, perform dynamic anchoring of the guy ropes. S3225, Jack Retraction and Load Conversion: After the standard section is added and the guy ropes are adjusted, the PLC controls all jacks to retract synchronously at a lower speed (≤2mm / min), causing the piston rod to retract until the newly added standard section of the lifting frame is fully stressed, and the jack oil pressure drops to the holding pressure (such as 10%-20% of the rated pressure). This step completes the smooth and shock-free conversion of the load from "active support of the hydraulic system" to "passive support of the steel structure support". S3226, System Reset, Preparing for the Next Cycle: The jack piston rod resets to the starting position of the next cycle, the system automatically resets, and is ready to start a new climbing cycle.

[0018] In one implementation, step S323 of the active dynamic stabilization system includes the following steps; S3231, System Composition: Stabilizing cable system: High-strength galvanized steel wire rope (such as Φ12mm) or steel strand is used as guy rope; Anchoring system: Pre-set three-ring graded anchoring rings (near, middle, and far) on the ground or permanent structure around the lifting support to form an anchoring matrix covering different heights and tension requirements; Intelligent adjustment device: Each guy rope is connected in series with a servo electric tie rod or hydraulic tension jack and equipped with a miniature tension sensor to form an independent "intelligent cable unit"; Attachment nodes: On the standard section of the lifting frame, a series of standardized, quick-release connecting lugs are pre-installed. Their positions are calculated to ensure that an optimal stable triangle can be formed at different heights. S3232, Dynamic stability control strategy: Graded and zoned stabilization: The entire lifting height is divided into three stabilization zones: low altitude zone (0-10m), mid altitude zone (10-15m) and high altitude zone (above 15m), with different guy rope configuration schemes for each zone; Active pretension control: Before the start of each jacking cycle, the system calculates and automatically applies an initial pretension (usually 5%-10% of the breaking tension of the guy rope) based on the next target height and the expected wind load to eliminate cable slack and provide initial stiffness. Force-position dual control and dynamic anchor changing: During lifting: The system monitors the tension changes of the guy ropes and the horizontal displacement of the top of the lifting frame in real time. When the horizontal displacement approaches the warning value (such as H / 800) or the tension is abnormal, the system can automatically fine-tune the tension of a specific "intelligent cable unit" to actively correct the deviation. During the hovering phase of the "lifting-adjustment" cycle, the guy ropes are anchored. The operation follows the principle of "hanging before removing and replacing in stages". When the lifting frame enters the hollow area, the new middle-layer guy ropes are hung at the preset higher position and tensioned to the design value before the old guy ropes at the bottom layer can be removed. This ensures the continuity of the stability system during the reconstruction process. Stability Quantitative Assessment: By real-time monitoring of the top horizontal displacement (required ≤H / 500) and guy rope tension fluctuation rate (required ≤±15%), the stability of the jacking system is quantitatively assessed and early warning is provided, realizing a leap from "experience-based judgment" to "data-driven" stable state assessment. In one embodiment, the structure and process of the high-precision synchronous lifting control system in step S33 are as follows: S331, System Composition: The actuator consists of multiple (e.g., 8) large-tonnage hydraulic jacks (e.g., rated thrust 600kN), each equipped with a high-precision displacement sensor (e.g., a grating ruler with an accuracy of ±0.1mm) and a pressure sensor. Control unit: It adopts a programmable logic controller (PLC) as the central processing core and is equipped with an industrial-grade human-machine interface (HMI) for real-time monitoring and command input; Power and drive unit: Composed of hydraulic pump station, electromagnetic proportional valve or servo valve. The proportional / servo valve receives instructions from PLC and precisely controls the flow and direction of hydraulic oil entering the jack, thereby achieving precise control of lifting speed and position. Communication network: Each sensor and PLC, and the PLC and each hydraulic valve are connected via industrial real-time Ethernet (such as Profinet, EtherCAT) or high-speed CAN bus to ensure the real-time performance and reliability of command and data transmission. The system cycle control cycle is less than 100ms. S332. Synchronous Control Strategy: This system adopts a comprehensive control algorithm that combines "master-slave following and average deviation compensation" rather than simple synchronous start and stop. Master-slave setting: Set one or more lifting points located at key stress points of the structure as master points, and the remaining points as slave points; Real-time tracking: The master point lifts according to a preset speed curve (such as an S-curve acceleration and deceleration to reduce impact), and the PLC collects the displacement data of all lifting points in real time; Deviation Compensation: The system calculates the displacement deviation between each driven point and the master point. When the height difference between any two lifting points exceeds the first threshold (e.g., 2mm), the system will automatically fine-tune the oil inlet valve opening of the jack that is running too fast, or perform a small flow compensation for the jack that is running too slow, so that it gradually catches up. When the height difference exceeds the second safety threshold (e.g., 5mm), the system will issue an audible and visual alarm. When it exceeds the third limit threshold (e.g., 10mm), the system will immediately enter an emergency stop state, and all hydraulic valves will be locked to ensure structural safety. S333, Refined Process of "Lifting-Raising" Cyclic Operation: S3331. Preparations before lifting and system self-test: Before the start of each lifting cycle, the operator triggers the "system self-test" command on the HMI. The PLC will automatically check the communication status of all sensors, the hydraulic system pressure, and whether the valve functions are normal. S3332. Synchronous lifting: When the operator issues a lifting command, the system lifts the entire space frame to the height of one standard section (e.g., 920mm) at a set speed (≤5mm / min). S3333, hydraulic locking and structural suspension: after the jacking is in place, the system automatically closes the oil inlet valve and return valve of all jacks, and uses the self-locking function of the hydraulic system to suspend the grid frame stably at the design height. At this time, the jacking frame bears the full load. S3334. Confirmation of support height and system stability: Under hydraulic locking and structural stability, workers add standard sections at the bottom or middle of the lifting frame. During this process, the PLC continuously monitors the pressure changes at each lifting point to ensure that the load is evenly distributed and there are no abnormal impacts during the heightening operation. S3335, Jack Retraction and Force Conversion: After the standard section is added, the PLC controls all jacks to retract synchronously and slowly, causing their piston rods to retract until the newly added standard section of the lifting frame is fully stressed, and the jacks are unloaded. This step completes the smooth conversion of the load from "hydraulic system support" to "steel structure support". S3336. System reset, prepare for the next cycle. After the jack piston rod is reset, the next "lifting-raising" cycle can begin. S334, Active Dynamic Stabilization System: In view of the characteristic that the stiffness of the "growth-type" jacking support changes with height, this invention designs an active dynamic stabilization system; S3341, The stable system is configured as follows: Guy ropes: made of high-strength galvanized steel wire rope (e.g., Φ10mm), with a breaking strength of not less than 50kN.

[0019] Anchoring points: Multiple anchoring rings of different radii (such as near-point anchoring and far-point anchoring) are pre-set on the surrounding ground or existing concrete structure to form an anchoring matrix.

[0020] Adjustment tools: Each guy rope is equipped with a turnbuckle and a tension sensor for precise adjustment and monitoring of the guy rope pretension.

[0021] Attached connectors: Multiple quick-release connecting lugs of different heights are pre-installed on the standard section of the lifting frame.

[0022] S3342, Dynamic stability control strategy: Graded and zoned stabilization: The jacking process is divided into multiple height zones. In the low-altitude zone (e.g., 0-10m), due to the high rigidity of the support, a guy rope can be installed at the top and anchored to a nearby anchor point. As the jacking height increases and enters the mid-to-high altitude zone (e.g., above 10m), a multi-level stabilization scheme is activated. Dynamic anchor replacement and force system reconfiguration: Pre-tensioning: Before jacking, based on the height of the next jacking stage, two guy ropes are pre-installed in the middle and top of the support. The middle guy rope mainly provides elastic support, while the top guy rope mainly resists the overturning moment. An initial pre-tensioning force (e.g., 2kN) is applied to all guy ropes to eliminate the inelastic deformation of the wire rope. Monitoring during jacking: During the jacking process, the PLC not only monitors the displacement, but also monitors the tension changes of the key guy ropes through tension sensors. The system will issue an early warning when the tension increases or decreases abnormally. Anchor Replacement Operation: Once the jacking support reaches a new height range, during the hydraulic locking and hovering phase of the "jacking-adjustment" cycle, the guy ropes are replaced. The original central guy rope is removed, its anchor point is moved to a more distant anchor ring, and a new central guy rope is installed at a higher position. This operation always follows the "install before removing" principle to ensure that at least one effective guy rope is always in operation. Stability Quantitative Assessment: By monitoring the horizontal displacement of the top of the lifting frame and the tension fluctuation of the guy ropes, the stability of the lifting system can be quantified in real time, controlling the horizontal displacement within 1 / 500 of the lifting height (e.g., ≤36mm for a height of 18m) and ensuring that the tension of the guy ropes is within a safe range, thus achieving measurable and controllable stability. S335. Lifting and Positioning and System Conversion Preparation: Continue lifting until the lower chord ball of the space frame reaches the design elevation. At this point, the space frame has been converted from a temporary support system of brick stacks on the ground to a support system supported by the lifting support system, providing operating space for the installation of the outer interlocking sections.

[0023] In one implementation, the specific process of high-altitude patching and system forming in step S4 is as follows: S41. Installation of peripheral interlocking sections: Using peripheral civil engineering scaffolding and hoisting equipment, interlocking sections of the grid are assembled in the gap between the core grid and the column top support. Through precise measurement and fine-tuning of the members, the smooth and accurate connection between the interlocking sections and the core area, and between the interlocking sections and the supports is ensured. S42. System conversion and unloading: After confirming that the welding of the intercalation section is qualified, the jacks are synchronously and slowly lowered (≤20mm each time) through the PLC control system to transfer the load of the space frame from the lifting support system to the permanent column top welded ball support. S43. Lifting System Removal and Secondary Structure Completion: After unloading, remove the lifting supports in sequence, then install the roof secondary purlins (C120×50×20×2.5mm) and tie rods to complete the installation of the entire roof steel structure system, and finally apply the fireproof coating.

[0024] The beneficial effects of this invention are as follows: 1. This invention is rationally designed. Through this construction method for large-span steel structure space frame roofs based on ground assembly and dynamically controllable jacking, it achieves ground assembly and dynamically controllable overall jacking for the installation of large-span steel structure space frame roofs. This effectively reduces the amount of high-altitude work and improves construction safety and quality. It solves the technical challenge of using large hoisting equipment for overall installation in complex or restricted sites. It achieves precision and controllability in the installation process of large-span space frames, effectively avoiding cumulative errors and structural deformation. Through a systematic "support-jacking-transfer" process, it ensures the stable and safe transfer of load to permanent supports, effectively guaranteeing the smooth installation of the entire roof.

[0025] 2. The core of this invention lies in adopting the overall technical approach of "ground-based integral assembly, CNC synchronous jacking, and high-altitude insertion and closure" to overcome the shortcomings of traditional technologies, such as high risks in high-altitude operations, difficulty in precision control, and strong dependence on large hoisting equipment. It is mainly divided into four stages: foundation and support system construction → ground-based low-altitude assembly and preparation → synchronous jacking and system conversion → high-altitude insertion and system formation. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the ground assembly and layout of the core space frame.

[0028] Figure 2 This is a diagram illustrating the placement of positioning brick stacks or pads.

[0029] Figure 3 This is a schematic diagram showing the placement of the four welded balls in the first layer.

[0030] Figure 4 This is a schematic diagram of assembling the first layer of the lower chord.

[0031] Figure 5 This is a schematic diagram of assembling the second layer of upper chord ball and diagonal brace.

[0032] Figure 6 This is a schematic diagram of the assembled core network structure.

[0033] Figure 7 This is a schematic diagram of a single lifting support.

[0034] Figure 8 This is a schematic diagram of an active dynamic stability system.

[0035] Figure 9 This is a diagram illustrating the process of the assembled core grid structure being embedded in the active dynamic stabilization system at high altitude.

[0036] Figure 10 This is a structural diagram of the assembled core space frame after it has been installed in place. Detailed Implementation

[0037] To make the technical problems, technical solutions, and technical effects of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0039] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0040] In the description of the embodiments of the present invention, it should be noted that the terms "inner", "outer", "upper", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0041] Example 1 like Figures 1 to 5 As shown, this embodiment provides a construction method for a large-span steel structure space frame roof based on ground assembly and dynamic controllable jacking, including the following steps: S1. Construction of foundation and support system; S2. Ground low-altitude assembly and preparation: finished poles and welded balls arrive on site → on-site inspection → setting up a temporary support system → core space frame ground overall assembly strategy → assembly process → precision control of outward assembly → main structure installation and preliminary protection; S3, Synchronous Lifting and System Conversion; S4, High-altitude patching and system forming.

[0042] In one embodiment, step S1 is as follows: S11. Precise pre-embedding and foundation construction: During the assembly process, the installed and inspected nodes are used as stable benchmarks, and the theoretical length of the subsequent members to be installed is used as rigid constraints to deduce and lock the spatial position of the new nodes in reverse. This method decomposes the global error into multiple local geometrically invariant systems, so that the error is absorbed and digested during the transmission process. S12. Support installation and fixing: Tower crane and truck crane work together to hoist the welded ball support to the design elevation of the top of the concrete column. After fine adjustment with total station and level, the upper support and the pre-embedded anchor bolt base are fixed firmly with electric arc welding (E43 welding rod) to form a permanent support point for the space frame.

[0043] Specifically, in addition to considering the relatively large load on the steel space frame and the possible deviation and error in the pre-embedded supports, stiffening plates are added to the conventional steel space frame supports to enhance their bearing capacity, and the anchor bolt holes are set as strip-shaped adjustable holes to achieve the function of adjusting the error.

[0044] In one embodiment, the specific steps of precise pre-embedding and foundation construction in step S11 are as follows: After each grid cell is assembled, a total station is used to remeasure the three-dimensional coordinates and compare the data with the BIM model. Any minor deviations will be actively corrected in the next grid cell assembly by fine-tuning the connection positions of the members (using bolt ball gaps or weld bevels). A total station was used for high-precision positioning and layout to ensure the position of the column top anchor bolts and the jacking frame foundation. The jacking frame foundation (2000mm×2000mm) is made of reinforced concrete. The pre-embedded anchor bolts are positioned by a special fixing frame, and the verticality deviation is controlled within 1 / 1000. This is the basis for the accuracy of the entire installation process.

[0045] In one embodiment, step S2 specifically includes the following: S21. Set up a temporary support system: Based on the design projection position of the lower chord ball of the space frame, set up a temporary support system on the ground with a certain strength (high-strength plastic, wooden blocks, brick blocks, etc.) as a temporary support. The top elevation deviation of the temporary support system is controlled within ±2mm to provide a flat and stable reference surface for ground assembly. S22. Core space frame ground assembly strategy: Strictly follow the assembly sequence of "from the center to the surroundings" and "lower chord → web members → upper chord", and gradually expand outwards based on small units (such as quadrilateral grids); S23. Assembly process: S24. Precision control of external expansion assembly: Using a total station for real-time tracking measurement, the three-dimensional spatial position of the next ball node is accurately determined by controlling the length of the three rods connected to the same welded ball, thereby effectively eliminating accumulated errors and achieving precision control. S25. Main Structure Installation and Preliminary Protection: Install the main purlins (120×80×4mm) on the upper chord of the core space frame assembled on the ground and spray fireproof coating to the design thickness (≥2.5mm). This ground-based approach to high-altitude work reduces the risks of high-altitude operations and improves installation efficiency and safety.

[0046] Specifically, the node connection method in the assembly process is as follows: high-strength bolts (such as M16 bolts, torque 100-120 N·m) or CO2 gas shielded welding (ER50-X welding wire) are used for connection to ensure node strength; In addition, the specific assembly process of the starting frame is as follows: First, install the grid frame with two grids in the center to form a small whole. On the ground, use temporary support points (240*240mm brick stacks or pads) to support the nine lower chord balls and connect the lower chord rods of these nine lower chord balls. Then, using the mutual positioning between the balls and rods, use two web rods to make an A-shape to install the upper chord balls of the second layer to form an integral structure. Based on the ball nodes in the drawings, determine the Z-coordinate and height difference of the lower chord ball. Then, according to the size of the sphere to be assembled in the central area, place brick stacks on the ground. Measure the central cross lines on each brick stack. Use steel pipe positioning rings to determine the position of the ball nodes and connect the members between the assembly nodes to form a lower chord quadrilateral unit grid. Then, use three web members to position the upper chord center ball, ensuring that the center of the upper chord ball matches the center of the ground projection. Connect the other two members to form a small unit reference control point. When assembling the space frame in each area, assemble it according to the assembly sequence of "lower chord - web member - upper chord" and "middle - both ends (span direction) - both ends (non-span direction)".

[0047] When placing the steel balls, make sure you know their specifications and numbers to avoid discrepancies between the numbers and the actual balls, which could cause unnecessary downtime or rework. When assembling, first fix the lower chord members and the welded balls together to form a square frame. Then, use a steel ruler and level to check the geometric dimensions of the space frame. Only after confirming that everything is correct can you continue assembling the lower grid space frame.

[0048] While assembling the lower chord grid, "V" shapes can be spot-welded on the ground. After installing the upper chord, install the "V" shapes, and then install the upper chord members of the space frame. After installing one grid, use a steel ruler to re-measure the geometric dimensions. If there are no errors, continue assembling the next grid in the same way until the space frame is assembled.

[0049] In addition, the precision control principle of the external expansion assembly is as follows: Since the core grid structure adopts the ground assembly method, after the small assembly unit is assembled and its installation accuracy is checked and qualified, the length of the three rods connected to the same welding ball is used as the control index to perform the spatial positioning of the next welding ball. As the area of ​​the assembled units changes continuously during the expansion process, the already assembled structure will undergo some overall elastic deformation due to the unchanged position of the lifting points. However, since the relative stiffness of each small unit is relatively large, the space frame will not deform locally. Therefore, during the expansion, the length of the rods is used as a positioning reference corresponding to the three other welded balls that have been installed, which will not cause cumulative errors to the overall space frame. During the assembly process, the cutting length of the space frame rods needs to be strictly controlled, and the influence of bolt gaps on the cutting length should be fully considered. After a portion of the small units is assembled, the coordinates of the corresponding positions should be converted in AutoCAD software using the 3D model of the space frame. The installation accuracy of the assembled small units should be checked using the converted relative coordinate positions. If deviations occur, adjustments should be made in the next small unit.

[0050] In one embodiment, step S23 is performed as follows: S231, Ground assembly and layout of the core space frame; S232. Place positioning brick stacks or pads; S233, Place the first layer of four welded balls; S234. Assemble the first layer of lower chord; S235, Assemble the second layer of topspin ball and diagonal brace; S236. After the central area is assembled, the assembly is gradually expanded outwards by using the mutual positioning between the ball and the stick until the core net frame is assembled.

[0051] In one embodiment, the specific process of synchronous lifting and system conversion in step S3 is as follows: S31. Installation and commissioning of the jacking system: Install jacking brackets composed of standard sections at the 8 preset jacking points, install the support plates on the top of the grid frame that match the upper chord ball, connect the hydraulic jacks (rated thrust 600kN) and the PLC synchronous control system, and conduct a trial jacking (jacking 100mm and then suspending for 24 hours) to check the system synchronization (deviation ≤2mm) and structural safety. S32, CNC synchronous lifting and dynamic stabilization: S321. High-precision synchronous lifting control system: This system integrates a programmable logic controller (PLC), a hydraulic servo / proportional system, and high-precision sensors to achieve high-precision synchronous lifting control. It includes the following components: S3211, System Hardware Configuration: Execution unit: Multiple large-tonnage hydraulic jacks (such as D160 / 100-1265 type, rated thrust 600kN) arranged in an array. Each jack is an independent control node. Considering the large tonnage, anti-tipping supports are set for the lifting support to ensure the stability and safety of the lifting jacks. Sensing Unit: Each jack piston rod end integrates a high-precision magnetostrictive displacement sensor (accuracy ±0.01%FS) to provide real-time feedback on piston rod stroke; a pressure sensor is installed at the jack oil circuit inlet to monitor load changes in real time; total station prisms or GNSS receivers are arranged on the top of the lifting frame and key nodes of the grid structure to form a spatial configuration monitoring system. Control unit: The core is an industrial-grade PLC, equipped with a high-speed analog input / output module for acquiring sensor signals and controlling valves, and an industrial real-time Ethernet module for high-speed communication within the system; Drive unit: The core control element of the hydraulic system is an electro-hydraulic proportional valve or servo valve. It has fast response speed and good control linearity. It can receive analog signals (such as 0-10V DC) sent by PLC and accurately and proportionally control the flow and direction of hydraulic oil. S3212. Synchronization Control Strategy and Algorithm: The system adopts a multi-mode intelligent synchronization control algorithm that combines "master-slave setting and average deviation correction", including the following modes: Master-slave setting mode: During the normal uniform lifting phase, a lifting point located in a region with high structural stiffness is designated as the master point, and the remaining points are slave points. The system controls all slave points to strictly follow the displacement-time curve of the master point. Average Deviation Correction Mode: The system calculates the average displacement of all lifting points in real time and compares the real-time displacement of each lifting point with the average displacement. When the deviation of any lifting point from the average displacement exceeds a first set threshold (e.g., ±2mm), the PLC outputs a fine-tuning command to the proportional valve at that point. This slightly depressurizes and slows down leading points, and slightly increases pressure and accelerates lagging points, achieving a "peak shaving and valley filling" style of coordinated deviation correction. Safety interlock: The system is equipped with a three-level alarm mechanism. When the deviation exceeds ±5mm, an audible and visual warning is issued; when it exceeds ±8mm, the system automatically reduces its speed; when it exceeds the limit value of ±10mm, the system immediately enters an emergency stop state, all proportional valves are closed and the hydraulic system is locked to ensure structural safety. S322, “Lifting-Reaching” Cyclic Climbing Operation Process; S323. Active dynamic stabilization system: In view of the characteristic that the stiffness of the continuously rising jacking support decreases with the increase of height, the present invention designs an active dynamic stabilization system that can adaptively adjust with the height. In step S33, the structure and process of the high-precision synchronous lifting control system.

[0052] In one embodiment, the "lifting-reaching" cyclic climbing operation process in step S322 is as follows: This process is the core of achieving the "self-growth" of the lifting frame, and its meticulous management is key to safety. Each cycle follows the standardized procedures below: S3221. System self-check and confirmation before lifting: The PLC automatically executes the system checklist, including: the communication status of all sensors, hydraulic system pressure, valve function, and initial height difference of each point. The system is only allowed to start lifting after the operator confirms "everything is normal" on the HMI interface. S3222, Synchronous Lifting Stage: When the operator issues the lifting command, the system lifts the entire space frame by one standard section height (920mm) according to the preset S-shaped speed curve (acceleration in the initial section, constant speed in the middle section, and deceleration in the final section to reduce hydraulic shock and structural dynamic load). The lifting speed is controlled at ≤5mm / min. S3223, Hydraulic Locking and Hovering Monitoring: After the jacking is in place, the PLC controls all proportional valves to return to the neutral position and triggers the hydraulic locking device to make the grid frame hover stably at the design height. The system enters the hovering monitoring mode and continuously monitors the pressure and displacement of each point for at least 30 minutes to confirm that there is no abnormal settlement or drift. S3224, Support Height and Stability Enhancement: Under hydraulic locking and absolute structural stability, workers add standard sections and, based on the current lifting height, perform dynamic anchoring of the guy ropes. S3225, Jack Retraction and Load Conversion: After the standard section is added and the guy ropes are adjusted, the PLC controls all jacks to retract synchronously at a lower speed (≤2mm / min), causing the piston rod to retract until the newly added standard section of the lifting frame is fully stressed, and the jack oil pressure drops to the holding pressure (such as 10%-20% of the rated pressure). This step completes the smooth and shock-free conversion of the load from "active support of the hydraulic system" to "passive support of the steel structure support". S3226, System Reset, Preparing for the Next Cycle: The jack piston rod resets to the starting position of the next cycle, the system automatically resets, and is ready to start a new climbing cycle.

[0053] In one embodiment, step S323 of the active dynamic stabilization system includes the following steps; S3231, System Composition: Stabilizing cable system: High-strength galvanized steel wire rope (such as Φ12mm) or steel strand is used as guy rope; Anchoring system: Pre-set three-ring graded anchoring rings (near, middle, and far) on the ground or permanent structure around the lifting support to form an anchoring matrix covering different heights and tension requirements; Intelligent adjustment device: Each guy rope is connected in series with a servo electric tie rod or hydraulic tension jack and equipped with a miniature tension sensor to form an independent "intelligent cable unit"; Attachment nodes: On the standard section of the lifting frame, a series of standardized, quick-release connecting lugs are pre-installed. Their positions are calculated to ensure that an optimal stable triangle can be formed at different heights. S3232, Dynamic stability control strategy: Graded and zoned stabilization: The entire lifting height is divided into three stabilization zones: low altitude zone (0-10m), mid altitude zone (10-15m) and high altitude zone (above 15m), with different guy rope configuration schemes for each zone; Active pretension control: Before the start of each jacking cycle, the system calculates and automatically applies an initial pretension (usually 5%-10% of the breaking tension of the guy rope) based on the next target height and the expected wind load to eliminate cable slack and provide initial stiffness. Force-position dual control and dynamic anchor changing: During lifting: The system monitors the tension changes of the guy ropes and the horizontal displacement of the top of the lifting frame in real time. When the horizontal displacement approaches the warning value (such as H / 800) or the tension is abnormal, the system can automatically fine-tune the tension of a specific "intelligent cable unit" to actively correct the deviation. During the hovering phase of the "lifting-adjustment" cycle, the guy ropes are anchored. The operation follows the principle of "hanging before removing and replacing in stages". When the lifting frame enters the hollow area, the new middle-layer guy ropes are hung at the preset higher position and tensioned to the design value before the old guy ropes at the bottom layer can be removed. This ensures the continuity of the stability system during the reconstruction process. Stability Quantitative Assessment: By real-time monitoring of the top horizontal displacement (required ≤H / 500) and guy rope tension fluctuation rate (required ≤±15%), the stability of the jacking system is quantitatively assessed and early warning is provided, realizing a leap from "experience-based judgment" to "data-driven" stable state assessment. In one embodiment, the structure and process of the high-precision synchronous lifting control system in step S33 are as follows: S331, System Composition: The actuator consists of multiple (e.g., 8) large-tonnage hydraulic jacks (e.g., rated thrust 600kN), each equipped with a high-precision displacement sensor (e.g., a grating ruler with an accuracy of ±0.1mm) and a pressure sensor. Control unit: It adopts a programmable logic controller (PLC) as the central processing core and is equipped with an industrial-grade human-machine interface (HMI) for real-time monitoring and command input; Power and drive unit: Composed of hydraulic pump station, electromagnetic proportional valve or servo valve. The proportional / servo valve receives instructions from PLC and precisely controls the flow and direction of hydraulic oil entering the jack, thereby achieving precise control of lifting speed and position. Communication network: Each sensor and PLC, and the PLC and each hydraulic valve are connected via industrial real-time Ethernet (such as Profinet, EtherCAT) or high-speed CAN bus to ensure the real-time performance and reliability of command and data transmission. The system cycle control cycle is less than 100ms. S332. Synchronous Control Strategy: This system adopts a comprehensive control algorithm that combines "master-slave following and average deviation compensation" rather than simple synchronous start and stop. Master-slave setting: Set one or more lifting points located at key stress points of the structure as master points, and the remaining points as slave points; Real-time tracking: The master point lifts according to a preset speed curve (such as an S-curve acceleration and deceleration to reduce impact), and the PLC collects the displacement data of all lifting points in real time; Deviation Compensation: The system calculates the displacement deviation between each driven point and the master point. When the height difference between any two lifting points exceeds the first threshold (e.g., 2mm), the system will automatically fine-tune the oil inlet valve opening of the jack that is running too fast, or perform a small flow compensation for the jack that is running too slow, so that it gradually catches up. When the height difference exceeds the second safety threshold (e.g., 5mm), the system will issue an audible and visual alarm. When it exceeds the third limit threshold (e.g., 10mm), the system will immediately enter an emergency stop state, and all hydraulic valves will be locked to ensure structural safety. S333, Refined Process of "Lifting-Raising" Cyclic Operation: S3331. Preparations before lifting and system self-test: Before the start of each lifting cycle, the operator triggers the "system self-test" command on the HMI. The PLC will automatically check the communication status of all sensors, the hydraulic system pressure, and whether the valve functions are normal. S3332. Synchronous lifting: When the operator issues a lifting command, the system lifts the entire space frame to the height of one standard section (e.g., 920mm) at a set speed (≤5mm / min). S3333, hydraulic locking and structural suspension: after the jacking is in place, the system automatically closes the oil inlet valve and return valve of all jacks, and uses the self-locking function of the hydraulic system to suspend the grid frame stably at the design height. At this time, the jacking frame bears the full load. S3334. Confirmation of support height and system stability: Under hydraulic locking and structural stability, workers add standard sections at the bottom or middle of the lifting frame. During this process, the PLC continuously monitors the pressure changes at each lifting point to ensure that the load is evenly distributed and there are no abnormal impacts during the heightening operation. S3335, Jack Retraction and Force Conversion: After the standard section is added, the PLC controls all jacks to retract synchronously and slowly, causing their piston rods to retract until the newly added standard section of the lifting frame is fully stressed, and the jacks are unloaded. This step completes the smooth conversion of the load from "hydraulic system support" to "steel structure support". S3336. System reset, prepare for the next cycle. After the jack piston rod is reset, the next "lifting-raising" cycle can begin. S334, Active Dynamic Stabilization System: In view of the characteristic that the stiffness of the "growth-type" jacking support changes with height, this invention designs an active dynamic stabilization system; S3341, The stable system is configured as follows: Guy ropes: made of high-strength galvanized steel wire rope (e.g., Φ10mm), with a breaking strength of not less than 50kN.

[0054] Anchoring points: Multiple anchoring rings of different radii (such as near-point anchoring and far-point anchoring) are pre-set on the surrounding ground or existing concrete structure to form an anchoring matrix.

[0055] Adjustment tools: Each guy rope is equipped with a turnbuckle and a tension sensor for precise adjustment and monitoring of the guy rope pretension.

[0056] Attached connectors: Multiple quick-release connecting lugs of different heights are pre-installed on the standard section of the lifting frame.

[0057] S3342, Dynamic stability control strategy: Graded and zoned stabilization: The jacking process is divided into multiple height zones. In the low-altitude zone (e.g., 0-10m), due to the high rigidity of the support, a guy rope can be installed at the top and anchored to a nearby anchor point. As the jacking height increases and enters the mid-to-high altitude zone (e.g., above 10m), a multi-level stabilization scheme is activated. Dynamic anchor replacement and force system reconfiguration: Pre-tensioning: Before jacking, based on the height of the next jacking stage, two guy ropes are pre-installed in the middle and top of the support. The middle guy rope mainly provides elastic support, while the top guy rope mainly resists the overturning moment. An initial pre-tensioning force (e.g., 2kN) is applied to all guy ropes to eliminate the inelastic deformation of the wire rope. Monitoring during jacking: During the jacking process, the PLC not only monitors the displacement, but also monitors the tension changes of the key guy ropes through tension sensors. The system will issue an early warning when the tension increases or decreases abnormally. Anchor Replacement Operation: Once the jacking support reaches a new height range, during the hydraulic locking and hovering phase of the "jacking-adjustment" cycle, the guy ropes are replaced. The original central guy rope is removed, its anchor point is moved to a more distant anchor ring, and a new central guy rope is installed at a higher position. This operation always follows the "install before removing" principle to ensure that at least one effective guy rope is always in operation. Stability Quantitative Assessment: By monitoring the horizontal displacement of the top of the lifting frame and the tension fluctuation of the guy ropes, the stability of the lifting system can be quantified in real time, controlling the horizontal displacement within 1 / 500 of the lifting height (e.g., ≤36mm for a height of 18m) and ensuring that the tension of the guy ropes is within a safe range, thus achieving measurable and controllable stability. S335. Lifting and Positioning and System Conversion Preparation: Continue lifting until the lower chord ball of the space frame reaches the design elevation. At this point, the space frame has been converted from a temporary support system of brick stacks on the ground to a support system supported by the lifting support system, providing operating space for the installation of the outer interlocking sections.

[0058] In one embodiment, the specific process of high-altitude patching and system forming in step S4 is as follows: S41. Installation of peripheral interlocking sections: Using peripheral civil engineering scaffolding and hoisting equipment, interlocking sections of the grid are assembled in the gap between the core grid and the column top support. Through precise measurement and fine-tuning of the members, the smooth and accurate connection between the interlocking sections and the core area, and between the interlocking sections and the supports is ensured. S42. System conversion and unloading: After confirming that the welding of the intercalation section is qualified, the jacks are synchronously and slowly lowered (≤20mm each time) through the PLC control system to transfer the load of the space frame from the lifting support system to the permanent column top welded ball support. S43. Lifting System Removal and Secondary Structure Completion: After unloading, remove the lifting supports in sequence, then install the roof secondary purlins (C120×50×20×2.5mm) and tie rods to complete the installation of the entire roof steel structure system, and finally apply the fireproof coating.

Claims

1. A construction method for a large-span steel structure net rack roof based on ground assembly and dynamic controllable jacking, characterized in that, Includes the following steps: S1. Construction of foundation and support system; S2. Ground low-altitude assembly and preparation: finished poles and welded balls arrive on site → on-site inspection → setting up a temporary support system → core space frame ground overall assembly strategy → assembly process → precision control of outward assembly → main structure installation and preliminary protection; S3, Synchronous Lifting and System Conversion; S4, High-altitude patching and system forming.

2. The construction method of long-span steel structure grid roof based on ground assembly and dynamic controllable jacking according to claim 1, characterized in that, The specific steps of step S1 are as follows: S11. Precise pre-embedding and foundation construction: During the assembly process, the installed and inspected nodes are used as a stable benchmark, and the theoretical length of the subsequent members to be installed is used as a rigid constraint to deduce and lock the spatial position of the new nodes in reverse. S12. Support installation and fixing: Tower crane and truck crane work together to hoist the welded ball support to the design elevation of the concrete column top. After fine adjustment with total station and level, the upper support and the pre-embedded anchor bolt base are fixed firmly with the anchor bolts by arc welding to form a permanent support point for the space frame.

3. The construction method of long-span steel structure space truss roof based on ground assembly and dynamic controllable jacking according to claim 2, characterized in that, In step S11, the specific steps for precise pre-embedding and foundation construction are as follows: After each grid cell is assembled, a total station is used to remeasure the three-dimensional coordinates, and the data is compared with the BIM model. Any minor deviations will be actively corrected in the next grid cell assembly by fine-tuning the connection positions of the members. A total station was used for high-precision positioning and layout to ensure the position of the column top anchor bolts and the jacking frame foundation. The jacking frame foundation adopted a reinforced concrete structure, and the pre-embedded anchor bolts were positioned by a special fixing frame. The verticality deviation was controlled within 1 / 1000, which is the basis for the accuracy of the entire installation process.

4. The construction method of long-span steel structure grid roof based on ground assembly and dynamic controllable jacking according to claim 2, characterized in that, In step S2, the assembly process is as follows: S21. Set up a temporary support system: According to the design projection position of the lower chord ball of the space frame, set up a temporary support system on the ground with a certain strength as a temporary support. The top elevation deviation of the temporary support system is controlled within ±2mm, so as to provide a flat and stable reference surface for ground assembly. S22. Core space frame ground assembly strategy: Strictly follow the assembly sequence of "from the center to the surroundings" and "lower chord → web members → upper chord", and gradually expand outward based on small units; S23. Assembly process: S24. Precision control of external expansion assembly: Using a total station for real-time tracking measurement, the three-dimensional spatial position of the next ball node is accurately determined by controlling the length of the three rods connected to the same welded ball, thereby effectively eliminating accumulated errors and achieving precision control. S25. Main Structure Installation and Preliminary Protection: On the upper chord of the core space frame assembled on the ground, install the main purlins and spray fireproof coating to the designed thickness, thus grounding the high-altitude operation, reducing the risk of high-altitude operation, and improving installation efficiency and safety.

5. The construction method for a large-span steel structure space frame roof based on ground assembly and dynamic controllable jacking according to claim 4, characterized in that, The specific method for step S23 is as follows: S231, Ground assembly and layout of the core space frame; S232. Place positioning brick stacks or pads; S233, Place the first layer of four welded balls; S234. Assemble the first layer of lower chord; S235, Assemble the second layer of topspin ball and diagonal brace; S236. After the central area is assembled, the assembly is gradually expanded outwards by using the mutual positioning between the ball and the stick until the core net frame is assembled.

6. The construction method for a large-span steel structure space frame roof based on ground assembly and dynamically controllable jacking according to claim 1, characterized in that, In step S3, the specific process of synchronous lifting and system conversion is as follows: S31. Installation and commissioning of the jacking system: Install jacking brackets composed of standard sections at the 8 preset jacking points, install support plates on the top of the grid frame that match the upper chord ball, connect the hydraulic jacks and the PLC synchronous control system, and conduct a trial jacking to verify the system's synchronization and structural safety. S32, CNC synchronous lifting and dynamic stabilization: S321. High-precision synchronous lifting control system: This system integrates a programmable logic controller, a hydraulic servo / proportional system, and high-precision sensors to achieve high-precision synchronous lifting control. It includes the following components: S3211, System Hardware Configuration Execution unit: Multiple large-tonnage hydraulic jacks arranged in an array, each jack serving as an independent control node; Sensing Unit: Each jack piston rod end integrates a high-precision magnetostrictive displacement sensor to provide real-time feedback on piston rod stroke; a pressure sensor is installed at the jack oil circuit inlet to monitor load changes in real time; total station prisms or GNSS receivers are arranged on the top of the lifting frame and key nodes of the grid structure to form a spatial configuration monitoring system. Control unit: The core is an industrial-grade PLC, equipped with a high-speed analog input / output module for acquiring sensor signals and controlling valves, and an industrial real-time Ethernet module for high-speed communication within the system; Drive unit: It adopts an electro-hydraulic proportional valve or servo valve as the core control element of the hydraulic system. It has fast response speed and good control linearity. It can receive analog signals sent by PLC and accurately and proportionally control the flow and direction of hydraulic oil. S3212. Synchronization Control Strategy and Algorithm: The system adopts a multi-mode intelligent synchronization control algorithm that combines "master-slave setting and average deviation correction", including the following modes: Master-slave setting mode: During the normal uniform jacking stage, a jacking point located in a region with high structural stiffness is designated as the master point, and the remaining points are slave points. The system controls all slave points to strictly follow the displacement-time curve of the master point. Average Deviation Correction Mode: The system calculates the average displacement of all lifting points in real time and compares the real-time displacement of each lifting point with the average displacement. When the deviation of any lifting point from the average displacement exceeds a first set threshold, the PLC outputs a fine-tuning command to the proportional valve at that point. This slightly depressurizes and slows down leading points, and slightly increases pressure and accelerates lagging points, achieving a "peak shaving and valley filling" style of coordinated deviation correction. Safety interlock: The system is equipped with a three-level alarm mechanism. When the deviation exceeds ±5mm, an audible and visual warning is issued; when it exceeds ±8mm, the system automatically reduces speed; when it exceeds the limit value of ±10mm, the system immediately enters emergency stop mode, all proportional valves close, and the hydraulic system locks to ensure structural safety. S322, "Lifting-Reaching" Cyclic Climbing Operation Process; S323. Active Dynamic Stabilization System: In view of the characteristic that the stiffness of the lifting support decreases with the increase of height, the present invention designs an active dynamic stabilization system that can adaptively adjust with the height.

7. The construction method for a large-span steel structure space frame roof based on ground assembly and dynamically controllable jacking according to claim 1, characterized in that, In step S322, the specific process of the "lifting-reaching" cyclic climbing operation is as follows: This process is the core of achieving the "self-growth" of the lifting frame, and its meticulous management is key to safety. Each cycle follows the standardized procedures below: S3221. System self-check and confirmation before lifting: The PLC automatically executes the system checklist, including: the communication status of all sensors, hydraulic system pressure, valve function, and initial height difference of each point. The system is only allowed to start lifting after the operator confirms "everything is normal" on the HMI interface. S3222, Synchronous Lifting Stage: When the operator issues the lifting command, the system lifts the entire grid structure to the height of one standard section according to the preset S-shaped speed curve, with the lifting speed controlled at ≤5mm / min; S3223, Hydraulic Locking and Hovering Monitoring: After the jacking is in place, the PLC controls all proportional valves to return to the neutral position and triggers the hydraulic locking device to make the grid frame hover stably at the design height. The system enters the hovering monitoring mode and continuously monitors the pressure and displacement of each point for at least 30 minutes to confirm that there is no abnormal settlement or drift. S3224, Support Height and Stability Enhancement: Under hydraulic locking and absolute structural stability, workers add standard sections and, based on the current lifting height, perform dynamic anchoring of the guy ropes. S3225, Jack Retraction and Load Conversion: After the standard section is added and the guy ropes are adjusted, the PLC controls all jacks to retract synchronously at a lower speed, causing the piston rod to retract until the newly added standard section of the lifting frame is fully stressed, and the jack oil pressure drops to the holding pressure. This step completes the smooth and shock-free conversion of the load from "active support of the hydraulic system" to "passive support of the steel structure support". S3226, System Reset, Preparing for the Next Cycle: The jack piston rod resets to the starting position of the next cycle, the system automatically resets, and is ready to start a new climbing cycle.

8. The construction method for a large-span steel structure space frame roof based on ground assembly and dynamic controllable jacking according to claim 6, characterized in that, In step S323, the active dynamic stabilization system includes the following steps; S3231, System Composition: Stabilizing cable system: High-strength galvanized steel wire rope or steel strand is used as guy rope; Anchoring system: Pre-set three-ring graded anchoring rings (near, middle, and far) on the ground or permanent structure around the lifting support to form an anchoring matrix covering different heights and tension requirements; Intelligent adjustment device: Each guy rope is connected in series with a servo electric tie rod or hydraulic tension jack and equipped with a miniature tension sensor to form an independent "intelligent cable unit"; Attachment nodes: On the standard section of the lifting frame, a series of standardized, quick-release connecting lugs are pre-installed. Their positions are calculated to ensure that an optimal stable triangle can be formed at different heights. S3232, Dynamic stability control strategy: Graded and zoned stabilization: The entire lifting height is divided into three stabilization zones: low altitude zone, mid altitude zone and high altitude zone, and each zone adopts a different guy rope configuration scheme; Active prestress control: Before the start of each jacking cycle, the system calculates and automatically applies an initial prestress based on the next target height and the expected wind load to eliminate cable slack and provide initial stiffness. Force-position dual control and dynamic anchor changing: During lifting: The system monitors the tension changes of the guy ropes and the horizontal displacement of the top of the lifting frame in real time. When the horizontal displacement approaches the warning value or the tension is abnormal, the system can automatically fine-tune the tension of a specific "intelligent cable unit" to actively correct the deviation. During the hovering phase of the "lifting-adjustment" cycle, the guy ropes are anchored and replaced. The operation follows the principle of "hanging before removing and replacing in stages". When the lifting frame enters the hollow area, the new middle-layer guy ropes are hung at the preset higher position and tensioned to the design value before the old guy ropes at the bottom layer can be removed. This ensures the continuity of the stability system during the reconstruction process. Stability Quantitative Assessment: By monitoring the top horizontal displacement and guy rope tension fluctuation rate in real time, the stability of the jacking system is quantitatively assessed and early warning is provided, realizing a leap from "experience-based judgment" to "data-driven" stable state.

9. The construction method for a large-span steel structure space frame roof based on ground assembly and dynamic controllable jacking according to claim 6, characterized in that, In step S33, the structure and process of the high-precision synchronous lifting control system are as follows: S331, System Composition: Actuation unit: Composed of multiple large-tonnage hydraulic jacks, each jack is equipped with a high-precision displacement sensor and pressure sensor; Control unit: It adopts a programmable logic controller as the central processing core and is equipped with an industrial-grade human-machine interface for real-time monitoring and command input; Power and drive unit: Composed of hydraulic pump station, electromagnetic proportional valve or servo valve. The proportional / servo valve receives instructions from PLC and precisely controls the flow and direction of hydraulic oil entering the jack, thereby achieving precise control of lifting speed and position. Communication network: Each sensor is connected to the PLC, and the PLC is connected to each hydraulic valve via industrial real-time Ethernet or high-speed CAN bus to ensure the real-time performance and reliability of command and data transmission. The system cycle control cycle is less than 100ms. S332. Synchronous Control Strategy: This system adopts a comprehensive control algorithm that combines "master-slave following and average deviation compensation" rather than simple synchronous start and stop. Master-slave setting: Set one or more lifting points located at key stress points of the structure as master points, and the remaining points as slave points; Real-time tracking: The master point rises according to the preset speed curve, and the PLC collects the displacement data of all rising points in real time; Deviation Compensation: The system calculates the displacement deviation between each driven point and the master point. When the height difference between any two lifting points exceeds the first threshold, the system will automatically fine-tune the oil inlet valve opening of the jack that is running too fast, or perform a small flow compensation for the jack that is running too slow, so that it gradually catches up. When the height difference exceeds the second safety threshold, the system will issue an audible and visual alarm. When it exceeds the third limit threshold, the system will immediately enter the emergency stop state, and all hydraulic valves will be locked to ensure structural safety. S333, Refined Process of "Lifting-Raising" Cyclic Operation: S3331. Preparations before lifting and system self-test: Before the start of each lifting cycle, the operator triggers the "system self-test" command on the HMI. The PLC will automatically check the communication status of all sensors, the hydraulic system pressure, and whether the valve functions are normal. S3332. Synchronous lifting: When the operator issues a lifting command, the system lifts the entire grid structure to the height of one standard section at the set speed. S3333, hydraulic locking and structural suspension: after the jacking is in place, the system automatically closes the oil inlet valve and return valve of all jacks, and uses the self-locking function of the hydraulic system to suspend the grid frame stably at the design height. At this time, the jacking frame bears the full load. S3334. Confirmation of support height and system stability: Under hydraulic locking and structural stability, workers add standard sections at the bottom or middle of the lifting frame. During this process, the PLC continuously monitors the pressure changes at each lifting point to ensure that the load is evenly distributed and there are no abnormal impacts during the heightening operation. S3335, Jack Retraction and Force Conversion: After the standard section is added, the PLC controls all jacks to retract synchronously and slowly, causing their piston rods to retract until the newly added standard section of the lifting frame is fully stressed, and the jacks are unloaded. This step completes the smooth conversion of the load from "hydraulic system support" to "steel structure support". S3336, System reset, prepare for the next cycle. After the jack piston rod is reset, the next "lifting-raising" cycle can begin. S334, Active Dynamic Stabilization System: In view of the characteristic that the stiffness of the "growth-type" jacking support changes with height, this invention designs an active dynamic stabilization system; S3341, The stable system is configured as follows: Guy ropes: Made of high-strength galvanized steel wire rope with a breaking strength of not less than 50kN; Anchoring points: Multiple anchoring rings of different radii are pre-set on the surrounding ground or existing concrete structure to form an anchoring matrix; Adjustment tools: Each guy rope is equipped with a turnbuckle and a tension sensor for precise adjustment and monitoring of the guy rope pretension; Attached connectors: Multiple quick-release connecting lugs of different heights are pre-installed on the standard section of the lifting frame; S3342, Dynamic stability control strategy: Graded and zoned stabilization: The jacking process is divided into multiple height zones. In the low-altitude zone, due to the high rigidity of the support, a guy rope can be installed at the top and anchored to a nearby anchor point. As the jacking height increases and enters the mid-to-high altitude zone, a multi-level stabilization scheme is activated. Dynamic anchor replacement and force system reconfiguration: Pre-tensioning: Before jacking, based on the height of the next jacking stage, two guy ropes are pre-installed in the middle and top of the support. The middle guy rope mainly provides elastic support, while the top guy rope mainly resists the overturning moment. An initial pre-tensioning force is applied to all guy ropes to eliminate the inelastic deformation of the wire rope. Monitoring during jacking: During the jacking process, the PLC not only monitors the displacement, but also monitors the tension changes of the key guy ropes through tension sensors. The system will issue an early warning when the tension increases or decreases abnormally. Anchor Replacement Operation: Once the jacking support reaches a new height range, during the hydraulic locking and hovering phase of the "jacking-adjustment" cycle, the guy ropes are replaced. The original central guy rope is removed, its anchor point is moved to a more distant anchor ring, and a new central guy rope is installed at a higher position. This operation always follows the "install before removing" principle to ensure that at least one effective guy rope is always in operation. Stability Quantitative Assessment: By monitoring the horizontal displacement of the top of the lifting frame and the tension fluctuation of the guy ropes, the stability of the lifting system can be quantified in real time, keeping the horizontal displacement within 1 / 500 of the lifting height and ensuring that the tension of the guy ropes is within a safe range, thus achieving measurable and controllable stability. S335. Lifting and Positioning and System Conversion Preparation: Continue lifting until the lower chord ball of the space frame reaches the design elevation. At this point, the space frame has been converted from a temporary support system of brick stacks on the ground to a support system supported by the lifting support system, providing operating space for the installation of the outer interlocking sections.

10. The construction method for a large-span steel structure space frame roof based on ground assembly and dynamically controllable jacking according to claim 1, characterized in that, In step S4, the specific process of high-altitude patching and system formation is as follows: S41. Installation of peripheral interlocking sections: Using peripheral civil engineering scaffolding and hoisting equipment, interlocking sections of the grid are assembled in the gap between the core grid and the column top support. Through precise measurement and fine-tuning of the members, the smooth and accurate connection between the interlocking sections and the core area, and between the interlocking sections and the supports is ensured. S42. System conversion and unloading: After confirming that the welding of the intercalation section is qualified, the jacks are synchronously and slowly lowered through the PLC control system to transfer the load of the space frame from the lifting support system to the permanent column top welded ball support. S43. Lifting System Removal and Secondary Structure Completion: After unloading, the lifting supports are removed in sequence, followed by the installation of roof secondary purlins and tie rods to complete the installation of the entire roof steel structure system, and finally the fireproof coating is applied.

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