Turnover steel roof reinforcement temporary support jig structure and construction method

Abstract

This invention relates to the field of steel structure construction technology, and discloses a reusable temporary support frame structure and construction method for reinforcing steel roofs. The structure includes several sets of support frame units and pedestrian walkway modules connecting adjacent units. Each support frame unit includes an adaptable base, reusable standard section components, and a cap support component. The adaptable base is divided into two types: horizontal ground type and stepped height difference type, adaptable to flat ground and complex installation base surfaces such as grandstand steps. The reusable standard section is constructed by bolting together tower crane standard sections, allowing for repeated reuse. This invention provides a reliable safety reserve for replacing and adjusting the tension of steel roof cables without applying additional loads to the original structure. It also has the advantages of high reusability, wide adaptability, high construction efficiency, and controllable safety, and can be widely applied to various large-span steel roof reinforcement and maintenance projects.

Description

Technical Field

[0001] This invention relates to the field of steel structure construction technology, and in particular to a reusable steel roof reinforcement temporary support frame structure and construction method. Background Technology

[0002] Large-span tensioned steel roof structures are widely used in large public buildings such as stadiums, convention centers, and transportation hubs due to their large span, light weight, aesthetically pleasing appearance, and excellent load-bearing performance. The load-bearing capacity and structural stability of such structures are highly dependent on the prestress state of the cable system. During long-term service, factors such as environmental corrosion, alternating loads, and material aging can cause problems such as rust, loosening, wire breakage, and prestress loss in the cables, seriously affecting the structural safety performance. Therefore, it is necessary to replace damaged cables and readjust and re-tension the entire cable net.

[0003] During the entire process of unloading, replacing, and re-tensioning the tension cables, the stress state of the steel roof space frame will change dynamically, which may lead to major safety risks such as excessive structural deformation, local stress concentration, or even space frame instability. Therefore, it is necessary to set up a temporary support frame system under the steel roof to provide redundant safety reserves for the main structure and ensure structural safety throughout the construction process.

[0004] The existing temporary support system for steel roof reinforcement has many shortcomings in practical engineering applications. First, it has poor reusability and high cost of temporary measures. The existing temporary support frame mostly adopts fixed lattice column structure welded on site. It is necessary to cut materials, weld and assemble them on site according to the project height. The installation and dismantling are difficult and the construction period is long. Moreover, after dismantling, the lattice columns cannot be reused due to non-standard size and welding damage, resulting in a lot of material waste and carbon emissions. The cost of temporary measures remains high.

[0005] Secondly, the poor adaptability of the installation base surface can easily cause additional damage to the original structure. Most of the existing frame bases are general-purpose flat structures that can only be adapted to flat concrete floors. However, large stadiums generally have complex installation base surfaces such as grandstand steps and staggered floor slabs. The existing bases cannot be effectively adapted, and the load of the frame is easily transferred to non-structural components such as decorative panels of the steps and floor slabs. This violates the core principle of reinforcement construction that does not apply additional loads to the original structure and can easily cause irreversible damage to the original building structure.

[0006] To address the numerous shortcomings of existing technologies, those skilled in the art require a reusable steel roof reinforcement temporary support frame structure and construction method. Summary of the Invention

[0007] The purpose of this invention is to overcome the above-mentioned defects of the prior art and provide a reusable steel roof reinforcement temporary support frame structure and construction method, so as to realize the standardization and modular design of the temporary support frame. By using reusable tower crane standard sections as the main body of the frame, the turnover and reuse rate of the support system is greatly improved and the cost of temporary measures is reduced.

[0008] The above-mentioned technical objective of the present invention is achieved through the following technical solution: A reusable temporary support frame structure for reinforcing steel roofs includes several sets of support frame units arranged along the area of ​​the steel roof to be reinforced, and a pedestrian walkway module connecting two adjacent sets of support frame units. The supporting tire frame unit includes an adapter base, a reusable standard section assembly, and a tire cap support assembly arranged coaxially from bottom to top. The reusable standard section assembly is formed by vertically splicing several tower crane standard sections, and adjacent tower crane standard sections are detachably fixedly connected by bolts; The adapter base includes a horizontal ground type base and a step height difference type base; the horizontal ground type base includes a base frame and a pre-embedded steel plate, the pre-embedded steel plate is fixed to the original structural concrete ground by chemical anchors, and the base frame and the pre-embedded steel plate are fully welded together; the step height difference type base includes a transfer beam and a combined base matching the transfer beam, the two ends of the transfer beam are supported on the top surface of the original structural concrete beam at the step, the combined base is provided with a low side section and a high side section, the low side section is welded to the transfer beam, and the high side section is welded to the pre-embedded steel plate on the high side of the step; The tire cap support assembly includes a tire cap frame, a support structure welded to the top of the tire cap frame, a support steel plate fixed above the support structure, and a jacking pipe fixed to the top surface of the support steel plate. The top end of the jacking pipe abuts against the bottom of the lower chord welded ball of the steel roof truss.

[0009] As a further feature of the present invention, the height of a single standard tower crane section is 2.8m, and it includes four main limb pipes, all of which are square pipes. Adjacent main limb pipes are welded together by diagonal bracing square pipes, crossbar square pipes, and top diagonal bracing square pipes.

[0010] As a further feature of the present invention, the pedestrian walkway module includes two sets of parallel I-beam main beams, angle iron secondary beams welded between the two sets of main beams, and a double-layer mahogany plywood template laid on top of the angle iron secondary beams. The template has openings on both sides and is fixed to the angle iron secondary beams by binding with double-strand iron wires. Several safety poles with a height of not less than 1.2m are welded along the length of both sides of the pedestrian walkway module, and at least two steel wire rope lifelines are installed on the top of the safety poles.

[0011] As a further feature of the present invention, the top surface elevation of the conversion beam of the stepped height difference type base is consistent with the top surface elevation of the steel plate pre-embedded on the higher side of the step, and the gap between the bottom surface of the conversion beam and the top surface of the original concrete structure beam is filled by a wedge-shaped steel plate assembly.

[0012] A construction method for a reusable steel roof reinforcement temporary support frame structure as described above, characterized by comprising the following steps: S1: Construction preparation and surveying: Verify the design drawings and original structural parameters, accurately measure the installation position and elevation of all support frame units, and distinguish and mark the installation points of horizontal ground type base and stepped height difference type base; S2: Base Installation: For horizontal ground installation points, after fixing the pre-embedded steel plates with chemical anchors, hoist the prefabricated base frame on the ground, level and center it, and then weld it to the pre-embedded steel plates. For stepped installation points, first hoist the transfer beam and level it, ensuring that both ends of the transfer beam are strictly supported on the original concrete structural beam. Then hoist the prefabricated composite base on the ground, aligning the lower section of the composite base with the transfer beam and the higher section with the pre-embedded steel plates on the higher side. After leveling, weld them to the base. After construction, conduct a special verification and acceptance of the load transfer path. S3: Reusable standard section assembly hoisting: For the frame with an installation height of less than 28m, multiple tower crane standard sections are assembled into an integral section on the ground and then hoisted; for sections with confined space at the top, single tower crane standard sections are hoisted, and adjacent tower crane standard sections are fastened together with bolts. S4: Installation of the tire cap support component: The process of pre-assembly on the ground and aerial relay hoisting by two truck cranes is adopted. The pre-assembly and welding of the tire cap frame and the support structure are completed on the ground. The main crane with the auxiliary boom and the auxiliary crane work together to hoist the pre-assembled tire cap support component to the top of the reusable standard section component and fix it in place. Then, the support steel plate and the jacking pipe are welded and installed so that the top of the jacking pipe abuts against the bottom of the lower chord welded ball of the steel roof grid. S5: Pedestrian walkway module installation: The process of ground modular prefabrication and high-altitude overall hoisting is adopted. The prefabrication and installation of pedestrian walkway modules are completed on the ground. After acceptance, the modules are hoisted as a whole between two adjacent sets of support frame units. After leveling and alignment, they are welded and fixed to the support frame units. After completion, a special acceptance is carried out. S6: Overall Acceptance and Commissioning: Conduct an overall acceptance inspection of the installation quality and structural stability of all support frame units and pedestrian walkway modules. Once the inspection is passed, the units will be officially put into use.

[0013] As a further feature of the present invention, in step S2, the load transfer path of the stepped height difference base is as follows: tower crane standard section, combined base frame, steel plate and chemical anchor bolts embedded on the high side / conversion beam on the low side, and original structural concrete beam. Only after confirming that the transfer path is clear and there are no weak links can the next process be carried out.

[0014] As a further feature of the present invention, in step S4, the working space of the tire cap support assembly is the clearance between the lower chord of the steel roof truss and the top of the reusable standard section assembly. The main crane is equipped with a secondary boom as an aerial boom extension, which works in conjunction with the auxiliary crane to complete the aerial relay hoisting, thus transforming the high-altitude welding and assembly operation into a ground pre-assembly operation.

[0015] As a further feature of the present invention, in step S5, after the pedestrian walkway module is installed, the maximum deflection of the walkway is no greater than 1 / 250 of its span.

[0016] The beneficial effects of this invention are: This invention provides a reusable temporary support frame structure and construction method for reinforcing steel roofs. The main body of the support frame adopts standardized tower crane sections, which are detachably connected by bolts, making installation and dismantling convenient and efficient. After dismantling, it can be completely reused in subsequent similar projects, completely solving the problem of poor reusability of traditional welded lattice columns. At the same time, it transforms a large amount of on-site welding work into standardized prefabrication in factories / prefabrication yards, significantly shortening the on-site construction cycle, reducing on-site welding workload, lowering labor costs, and reducing steel waste and carbon emissions.

[0017] This invention addresses two common installation base types in large venues: flat ground and grandstand steps, as well as staggered floor slabs. It designs two types of adaptable bases: a horizontal ground type and a step height difference type. The step height difference type base uses a large-section transfer beam to directly transfer the load of the support frame across the step space to the original concrete main load-bearing beam. This avoids the load acting on non-structural components such as the step decorative layer and floor slab, and eliminates the additional load and irreversible damage to the original structure caused by the temporary support system. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the overall structure of this embodiment; Figure 2 This is a plan view of the overall structure of this embodiment; Figure 3This is a schematic diagram of the reusable standard section component structure in this embodiment; Figure 4 This is a schematic diagram of the horizontal ground-type base structure in this embodiment; Figure 5 This is a schematic diagram of the stepped height difference type base structure in this embodiment; Figure 6 This is a schematic diagram of the tire cap support assembly structure in this embodiment; Figure 7 This is a schematic diagram of the pedestrian walkway module structure in this embodiment; In the diagram, 1. Support frame unit, 11. Adaptor base, 111. Horizontal ground type base, 1111. Base frame, 1112. Embedded steel plate, 112. Step height difference type base, 1121. Combined base, 12. Reusable standard section assembly, 13. Tire cap support assembly, 131. Support structure, 132. Support steel plate, 133. Jacking pipe, 2. Pedestrian walkway module, 21. I-beam main beam, 22. Safety pole, 23. Steel wire rope lifeline. Detailed Implementation

[0020] The technical solution of the present invention will now be clearly and completely described with reference to specific embodiments. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] The invention will be further described in detail below with reference to a specific engineering embodiment. This embodiment takes the reinforcement project of the steel roof of a large stadium as the application scenario. The stadium roof is a large-span tensioned cable truss structure. Due to long-term service, some tension cables have suffered damage such as corrosion and prestress loss. It is necessary to replace the damaged cables of the entire cable network and re-tension the overall cable force. To ensure the safety of the main truss structure during construction, 32 temporary support frames need to be set up along the area of ​​the steel roof to be reinforced without applying additional loads to the original structure. Pedestrian walkways connecting adjacent support frames are also provided to form a complete working platform and safety reserve system.

[0022] This embodiment provides a reusable temporary support frame structure for reinforcing a steel roof, referencing... Figures 1 to 7 It includes 32 sets of support frame units 1 evenly distributed along the area to be reinforced on the steel roof, and pedestrian walkway modules 2 connecting two adjacent sets of support frame units 1. The span of the pedestrian walkway modules 2 is set to 7m~14m according to the spacing between adjacent frames, and the maximum calculated span is 18.5m, which meets the operation and passage requirements of the entire area in the venue.

[0023] Each support frame unit 1 includes an adapter base 11, a reusable standard section assembly 12, and a tire cap support assembly 13, which are coaxially arranged from bottom to top. The coaxial arrangement of the three ensures that the load is evenly transmitted vertically and avoids eccentric force.

[0024] The reusable standard section assembly 12 is vertically spliced ​​from several tower crane standard sections. Adjacent tower crane standard sections are detachably fixed together using high-strength bolts, allowing for convenient installation and disassembly. After removal, it can be reused intact. In this embodiment, a single tower crane standard section is 2.8m high and weighs 996kg. For construction verification, it is calculated as 1 ton. The highest support frame consists of 9 standard sections spliced ​​together, with a total height of 25.2m. The four main tubes of each single tower crane standard section are all made of 132*132*10 Q355B square tubing. Adjacent main tubes are welded together using 68*68*4 diagonal bracing square tubing, 50*50*4 crossbar square tubing, and 60*60*4 top diagonal bracing square tubing. The overall structure has high rigidity and excellent load-bearing performance, fully meeting the load-bearing requirements of temporary supports.

[0025] The adapter base 11 is divided into two types according to the different installation base surfaces: horizontal ground type base 111 and step height difference type base 112. In this embodiment, 18 support frames are installed on the flat concrete ground inside the venue, using horizontal ground type base 111; 14 support frames are installed in the grandstand step area, using step height difference type base 112. The horizontal ground type base 111 includes a base frame 1111 and a pre-embedded steel plate 1112. The pre-embedded steel plate 1112 is fixed to the original structural concrete ground by chemical anchors, and the base frame 1111 and the pre-embedded steel plate 1112 are fully welded together. In this embodiment, the base frame 1111 is assembled into a rectangular frame using HW300*300*10*15 H-shaped steel. The embedded steel plate 1112 has a specification of PL20*450*440. Each embedded steel plate 1112 is equipped with four M18*220 chemical anchors and is fixed to the C35 concrete floor inside the venue. The pull-out force of the chemical anchors has been tested and meets the design requirements. After the base frame 1111 is hoisted and leveled, it is fully welded to the embedded steel plate 1112 to ensure that the load of the frame is evenly transferred to the original concrete floor. The step height difference type base 112 includes a transfer beam and a combined base 1121 that matches the transfer beam. The two ends of the transfer beam are supported on the top surface of the original concrete structural beam at the step. It is strictly forbidden to support it on non-structural components such as the decorative panel of the step. The lower side section of the combined base 1121 is welded to the transfer beam, and the higher side section is welded to the embedded steel plate on the higher side of the step. In this embodiment, the transfer beam is made of HW400*400*13*21 H-beams, and the combined base 1121 is made of H-beams of the same specification as the transfer beam, welded into an L-shaped frame. The top surface elevation of the transfer beam is completely consistent with the top surface elevation of the steel plate embedded on the high side of the step, forming a continuous and horizontal installation reference surface. Where the bottom surface of the transfer beam is not in close contact with the top surface of the original concrete beam, it is shimmed by wedge-shaped steel plates to ensure that the contact surface is flat, the force is uniform, and there is no suspension.

[0026] The tire cap support assembly 13 includes a tire cap frame, a support structure 131 welded to the top of the tire cap frame, a support steel plate 132 fixed above the support structure 131, and a jacking pipe 133 fixed to the top surface of the support steel plate 132. The top end of the jacking pipe 133 abuts against the bottom of the lower chord welded ball of the steel roof space frame. In this embodiment, the tire cap frame is assembled from HW300*300*10*15 H-shaped steel. The support structure 131 is a triangular truss structure to ensure the rigidity and stability of the top support. The support steel plate 132 has a specification of PL20*300. The jacking pipe 133 is a Φ300*10 seamless steel pipe. The length of the jacking pipe 133 is customized according to the distance between the top of the tire frame and the bottom of the lower chord welded ball measured on site. After installation, the top end of the jacking pipe 133 abuts tightly against the bottom of the lower chord welded ball. There is no need to use jacks for pre-loading. It only provides safety support when the main structure undergoes abnormal deformation during cable force adjustment, strictly avoiding applying additional loads to the original structure space frame.

[0027] The pedestrian walkway module 2 serves as a safe passage for high-altitude operations, connecting the adjacent support frame unit 1. It is a core facility that ensures the safe passage of construction personnel and the safe transfer of small tools. In this embodiment, the pedestrian walkway module 2 includes two sets of parallel I20 I-beam main beams 21, and L75*5 angle iron cross braces and diagonal secondary beams welded between the two sets of main beams. The main beams and secondary beams are welded to form a stable truss-type integral beam structure. A double-layer 20mm thick 1830*950 mahogany plywood template is laid on top of the secondary beams. Holes are opened on both sides of the template at intervals, and the template is firmly tied to the angle iron secondary beams below with double-stranded 1.2mm diameter iron wire to ensure that the template does not move or tilt, and has excellent anti-slip performance. Every 7m along the length of both sides of the pedestrian walkway module 2, a Φ50*3 safety pole 22 with a height of not less than 1.2m is welded. Two 10mm diameter steel wire rope lifelines 23 are installed on the top of the safety pole 22. The two ends of the steel wire rope are tensioned by turnbuckles and anchored to the special ear plate at the end of the passage to form a reliable fall protection system. The installation elevation of pedestrian walkway module 2 is 90cm below the bottom of the original structure's inverted column of the bridle, to avoid interference with the original bridle structure of the venue and ensure sufficient passage space.

[0028] The support system in this embodiment has undergone specialized structural calculations, and all indicators meet the requirements of current national standards: the maximum stress ratio of the structure is 0.75 < 1.0, and the bearing capacity meets the requirements; the maximum horizontal deformation at the top of the support frame is 6.3 mm < 32000 / 120 = 266 mm, which is within the standard limit; the minimum buckling coefficient is 18.7 > 4.2, which is within the standard limit, and the stability meets the requirements; the maximum deflection of the pedestrian walkway is 58.3 mm < 18500 / 250 = 74 mm, which is within the standard limit, and the deflection meets the requirements; the foundation bearing capacity, shear resistance, punching shear resistance, reinforcement at the floor slab, and crack width have all been verified and fully meet the construction safety requirements.

[0029] A safe and efficient construction method for a reusable steel roof reinforcement temporary support frame structure includes the following steps: S1: Construction Preparation and Surveying / Setting Out First, complete the technical preparations, review the design drawings and structural calculations, clarify the specifications, installation requirements, and stress performance of each component, and prepare a special hoisting plan, a special safety construction plan, and an emergency plan. Conduct comprehensive safety and technical briefings for all management and operational personnel involved in the construction to ensure that everyone understands the construction process, key operating points, and safety control requirements. Then, complete the preparation of materials and equipment. All raw materials, including tower crane standard sections, H-beams, steel plates, chemical anchors, and wire ropes, have arrived on site and undergone on-site inspection, with complete quality certification documents and performance meeting design requirements. All equipment, including a 50-ton truck crane, a 25-ton truck crane, welding machines, total stations, levels, and torque wrenches, have arrived on site and been tested. Hoisting slings and shackles have passed inspection and meet safety requirements. Finally, the surveying and layout work was completed. Using a total station and a level, the installation positions and elevations of the 32 supporting frame units 1 were accurately measured and marked. The installation points of the horizontal ground type and the step height difference type base 112 were distinguished and marked. The position, elevation, and cross-sectional dimensions of the concrete structural beam at the grandstand steps were thoroughly investigated and verified to ensure that the installation position of the transfer beam was accurate and that both ends could be effectively supported on the structural beam.

[0030] S2: Installation of base adapter 11 For different types of installation points, corresponding construction processes are adopted: For horizontal ground installation points, firstly, the pre-embedded steel plate 1112 is installed at the marked installation location and fixed to the original concrete ground using M18*220 chemical anchors. After the chemical anchors are installed, the pull-out force is tested, and subsequent construction can only proceed after the test is qualified. The base frame 1111 is prefabricated and welded to the ground in the prefabrication site to ensure that the flatness and dimensional deviation of the frame meet the specifications. A 25-ton truck crane is used to lift the prefabricated base frame 1111 into place. The levelness of the frame is adjusted using a level instrument. After leveling and centering, the base frame 1111 is fully welded to the pre-embedded steel plate 1112. After welding, the weld quality is visually inspected and non-destructively tested. After acceptance, the next process begins.

[0031] For installation points with step height differences, the transfer beam is installed and leveled first. A 25-ton truck crane is used to hoist the HW400*400*13*21H steel transfer beam into place, ensuring that both ends of the transfer beam are strictly supported on the top surface of the pre-marked original structural concrete beam. It is strictly forbidden for the beam to be suspended or only supported on the decorative panel of the step. For areas where the bottom surface of the transfer beam is not in close contact with the top surface of the structural beam, wedge-shaped steel plates are used to padded the surface to ensure that the contact surface is flat and the stress is even. A level is used to measure and adjust the top surface elevation of the transfer beam to make it consistent with the top surface elevation of the steel plate pre-embedded on the higher side of the step, forming a continuous and horizontal installation reference surface. If necessary, a leveling steel plate can be welded to the top surface of the transfer beam for precise control. After the transfer beam is installed, the ground prefabrication of the combined base 1121 is carried out. H-beams of the same specifications as the transfer beam are welded into an L-shaped combined frame to ensure that the strength and rigidity of the welded joints meet the design requirements. The prefabricated combined base 1121 is hoisted into place by a truck crane, so that its lower side section is accurately placed on the leveled transfer beam below, and the higher side section is aligned with the embedded steel plate on the higher side of the step. Initial spot welding is performed to fix it, and then the levelness of the entire frame top surface is re-measured and final fine-tuned. After the adjustment is correct, the higher side section is fully welded to the embedded steel plate and the lower side section is reliably welded to the transfer beam below. After the construction of the stepped height difference base 112 is completed, a special verification and acceptance of the load transfer path must be carried out. This acceptance is a mandatory acceptance item and requires both written and on-site confirmation. The load transfer path of the stepped height difference base 112 must be clearly defined as follows: tower crane standard section → combined base 1121 → steel plate and chemical anchors embedded on the high side / transfer beam on the low side → original structural concrete beam. The transfer path must be confirmed to be clear, direct and without weak links. Only after the acceptance is qualified can the next process be carried out.

[0032] S3: 12 reusable standard section components for hoisting The hoisting sequence followed the principle of "farthest before nearest," prioritizing the hoisting of the six supporting frames at the fourth-floor grandstand, followed by the hoisting of the supporting frames at the inner field ground and the second and third floors. All standard sections were hoisted using a 50-ton truck crane, and the load rate for all hoisting conditions was strictly controlled below 80%, meeting hoisting safety regulations. For frames with an installation height below 28m, three tower crane standard sections were assembled on the ground into a single section, with a total weight of approximately 3 tons per section. At the furthest hoisting radius of 23.5m, the 50-ton truck crane extended its boom to 37m. Under this condition, the rated lifting capacity was 5.2 tons, and the hoisting load rate was 58%, far below the 80% limit, providing sufficient safety redundancy. After the single section was assembled, it was hoisted into place using a truck crane and then bolted to the base frame 1111 below. For the standard section in the confined space section, i.e. the topmost standard section of the formwork, the clearance between the lower chord of the steel roof truss and the top of the formwork is only 2m, which is considered an extremely confined space. A single tower crane standard section is used for hoisting. The maximum total weight of a single standard section plus the formwork cap is 2.2 tons. With a 50-ton truck crane boom of 38.5m and a hoisting radius of 23.5m, the rated lifting capacity is 5.2 tons, and the hoisting load rate is 43%, which meets the hoisting requirements. During hoisting, the wire rope is tied to the middle member of the standard section to shorten the distance between the hook and the formwork, which is suitable for the operation requirements of the extreme clearance. After the single standard section is hoisted into place, it is fastened to the standard section below with bolts.

[0033] S4: Tire cap support assembly 13 installation To address the extremely limited clearance of the work environment, where the top of the tire cap is only 2 meters from the lower chord of the steel roof truss, this embodiment innovatively adopts a "ground pre-assembly + aerial relay coordinated hoisting" process. This transforms most of the high-altitude welding and assembly work into ground operations, significantly improving construction safety and installation accuracy. First, the tire cap frame and support structure 131 are pre-assembled and welded on the ground to ensure that the welding quality and structural dimensions meet the design requirements. At the same time, the design and welding of the lifting lugs are completed. Then, the main crane is equipped with a secondary boom as an extension of the aerial boom. After positioning and confirming that the working conditions meet the hoisting requirements, the auxiliary crane is simultaneously positioned. The two cranes work together to complete the aerial relay hoisting, smoothly and accurately sending the pre-assembled tire cap support component 13 to the target position under the truss. After positioning, it is temporarily fixed to the top of the reusable standard section component 12. After verifying that the position and level are correct, the final welding and fixing are completed. After the tire cap frame is fixed, the actual distance between the top of the tire frame and the bottom of the welded ball of the lower chord of the steel roof grid is measured on site. The corresponding length of the jacking pipe 133 is processed, and the supporting steel plate 132 and the jacking pipe 133 are welded and installed in sequence to ensure that the top of the jacking pipe 133 is in close contact with the bottom of the welded ball of the lower chord. There is no need to use jacks for pre-loading, which is only used as a safety reserve in case of abnormal structural deformation.

[0034] S5: Installation of pedestrian walkway module 2 The construction of pedestrian walkway module 2 follows the principle of "modular prefabrication on the ground and integrated installation at high altitude" to minimize the amount of high-altitude work and ensure construction safety and installation quality. First, the ground of the pedestrian walkway module 2 is prefabricated at the prefabrication site. Based on the design length of each passageway, the I-beam main beams 21 are precisely cut. The two main beams are placed parallel to each other, and angle iron cross braces and diagonal braces are welded at the designed intervals to form a stable truss-type integral beam. All welds are full and firm to ensure no deformation occurs during hoisting and use. Then, a double layer of 20mm thick mahogany plywood formwork is laid above the angle iron secondary beams. Holes are made on both sides of the formwork, and it is securely tied to the angle iron secondary beams with double-strand 1.2mm diameter iron wire. Finally, safety protection facilities are installed. Vertical safety poles 22 are welded every 7m along both sides of the passageway. The poles are at least 1.2m high and firmly welded to the main beams at the bottom. Two steel wire rope lifelines 23 are installed along the top of the poles, passing through pre-set holes at the top of the poles. Both ends are tensioned and anchored to special ear plates at the ends of the passageway using turnbuckles. After prefabrication, the entire passageway is inspected to check the structural dimensions, welding quality, formwork fixation, and the integrity of the safety facilities. After acceptance, the hoisting point positions are marked. After prefabrication and acceptance, a 50-ton truck crane with a balancing hoist was used to horizontally lift the prefabricated pedestrian walkway module 2 from the ground. During the lifting process, guy ropes were used to control the walkway's posture and prevent rotation and collision. The walkway was then slowly lowered between two adjacent support frame units 1. High-altitude operators coordinated the alignment and used hand-operated hoists to finely adjust the walkway's position and elevation, ensuring that the supports at both ends of the walkway were accurately aligned with the pre-marked installation positions on the frame. After installation, the walkway was horizontal, and the installation elevation was strictly controlled to be 90cm below the bottom of the original structure's hanging columns to avoid interference with the existing structure. The maximum deflection of the walkway after installation was no more than 1 / 250 of its span, meeting specifications and usage requirements. After confirming the position and elevation were correct, the supports at both ends of the walkway were immediately welded and fixed to the support frame units 1. The welds must be strong and reliable to ensure they can withstand pedestrian traffic and accidental impact loads. After installation, a special inspection was conducted on the levelness of the passage, the quality of the fixed welds, and the tension and anchoring reliability of the lifeline wire rope. After the inspection was passed, a sign that read "Safety Passage, Load and Speed ​​Limits" was hung at the entrance of the passage. All construction personnel were given instructions on its use, clarifying that the passage was only for personnel passage and the transfer of small tools, and was strictly prohibited from being used as a platform for storing or transferring heavy materials.

[0035] S6: Overall Acceptance and Commissioning After all supporting frame units 1 and pedestrian walkway modules 2 are installed, the construction unit, supervision unit, and construction unit will conduct an overall acceptance inspection. The inspection will include the installation position, elevation, levelness, bolt tightening torque, and weld quality of the supporting frame; the installation quality and integrity of safety protection facilities of pedestrian walkway modules 2; and the final confirmation of the load transfer path. Once all indicators meet the design and current national standards, the system will be officially put into use. During the use of the support system, dedicated personnel will conduct daily inspections and maintenance of the connection nodes of the supporting frame, the fixed welds of the pedestrian walkway, and the safety protection facilities. Any problems found will be rectified immediately to ensure that the system remains safe and reliable throughout the entire steel roof reinforcement construction process.

[0036] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A recyclable steel roof bracing temporary support jig structure characterized by, It includes several sets of support frame units (1) arranged along the area to be reinforced of the steel roof, and pedestrian walkway modules (2) connecting two adjacent sets of support frame units (1). The supporting tire frame unit (1) includes an adapter base (11), a reusable standard section assembly (12), and a tire cap support assembly (13) arranged coaxially from bottom to top. The reusable standard section assembly (12) is formed by vertically splicing several tower crane standard sections, and adjacent tower crane standard sections are detachably fixedly connected by bolts; The adapter base (11) includes a horizontal ground type base (111) and a step height difference type base (112); the horizontal ground type base (111) includes a base frame (1111) and a pre-embedded steel plate (1112), the pre-embedded steel plate (1112) is fixed to the original structural concrete ground by chemical anchors, and the base frame (1111) and the pre-embedded steel plate (1112) are fully welded together; the step height difference type base (112) includes a transfer beam and a combined base (1121) matching the transfer beam, the two ends of the transfer beam are supported on the top surface of the original structural concrete beam at the step, and the combined base (1121) is provided with a low side section and a high side section, the low side section is welded to the transfer beam, and the high side section is welded to the steel plate pre-embedded on the high side of the step; The tire cap support assembly (13) includes a tire cap frame, a support structure (131) welded to the top of the tire cap frame, a support steel plate (132) fixed above the support structure (131), and a jacking pipe (133) fixed to the top surface of the support steel plate (132). The top end of the jacking pipe (133) abuts against the bottom of the lower chord welded ball of the steel roof grid.

2. A recyclable steel roof strengthening temporary support jig structure according to claim 1, wherein, The height of a single standard tower crane section is 2.8m, and it includes four main tubes, all of which are square tubes. Adjacent main tubes are welded together by diagonal bracing square tubes, crossbar square tubes, and top diagonal bracing square tubes.

3. A recyclable steel roof strengthening temporary support jig structure according to claim 1, wherein, The pedestrian walkway module (2) includes two sets of parallel I-beam main beams (21), angle iron secondary beams welded between the two sets of main beams, and a double-layer mahogany plywood template laid on top of the angle iron secondary beams. The template has holes on both sides and is fixed to the angle iron secondary beams by binding with double-strand iron wires. Several safety poles (22) with a height of not less than 1.2m are welded on both sides of the pedestrian walkway module (2) along the length direction. At least two steel wire rope lifelines (23) are installed on the top of the safety poles (22) along the entire length.

4. The recyclable steel roof strengthening temporary support jig structure of claim 1, wherein The elevation of the top surface of the transition beam of the stepped height difference type base (112) is consistent with the elevation of the top surface of the steel plate pre-embedded on the high side of the step. The gap between the bottom surface of the transition beam and the top surface of the original concrete structure beam is filled by wedge-shaped steel plates.

5. A construction method for a reusable steel roof reinforcement temporary support frame structure as described in any one of claims 1-4, characterized in that, Includes the following steps: S1: Construction preparation and surveying: Review the design drawings and original structural parameters, accurately measure the installation position and installation elevation of all support frame units (1), and distinguish and mark the installation points of horizontal ground type base (111) and step height difference type base (112); S2: Construction of the base (11): For horizontal ground type installation points, after the chemical anchor bolts of the pre-embedded steel plate (1112) are fixed, the prefabricated base frame (1111) is hoisted, leveled and aligned, and then fully welded to the pre-embedded steel plate (1112); For step height difference type installation points, the conversion beam is hoisted and leveled first, so that both ends of the conversion beam are strictly supported on the original concrete structure beam, and then the prefabricated combination base (1121) is hoisted, so that the low side section of the combination base (1121) is aligned with the conversion beam and the high side section is aligned with the pre-embedded steel plate on the high side. After leveling, they are welded and fixed respectively. After the construction is completed, the load transfer path is specially verified and accepted. S3: Reusable standard section assembly (12) hoisting: For the frame with an installation height of less than 28m, multiple tower crane standard sections are assembled into an integral section on the ground and then hoisted; for the section with limited space at the top, a single tower crane standard section is hoisted and adjacent tower crane standard sections are fastened together with bolts. S4: Installation of the tire cap support assembly (13): The process of ground pre-assembly and aerial relay hoisting by two truck cranes is adopted. The pre-assembly and welding of the tire cap frame and the support structure (131) are completed on the ground. The main crane with the auxiliary boom and the auxiliary crane work together to hoist the pre-assembled tire cap support assembly (13) to the top of the reusable standard section assembly (12) and fix it in place. Then, the support steel plate (132) and the jacking pipe (133) are welded and installed so that the top of the jacking pipe (133) abuts against the bottom of the lower chord welded ball of the steel roof grid. S5: Installation of pedestrian walkway module (2): The process of ground modular prefabrication and high-altitude overall hoisting is adopted. The prefabrication and installation of pedestrian walkway module (2) is completed on the ground. After acceptance, it is hoisted as a whole between two adjacent sets of support frame units (1). After leveling and alignment, it is welded and fixed to the support frame unit (1). After completion, a special acceptance is carried out. S6: Overall Acceptance and Put into Use: The installation quality and structural stability of all support frame units (1) and pedestrian walkway modules (2) shall be inspected and accepted. After passing the inspection, they shall be put into use.

6. The construction method according to claim 5, characterized in that, In step S2, the load transfer path of the stepped height difference base (112) is as follows: tower crane standard section, combined base (1121), steel plate and chemical anchor bolts embedded on the high side / conversion beam on the low side, and original structural concrete beam. Only after confirming that the transfer path is clear and there are no weak links can the next process be carried out.

7. The construction method according to claim 5, characterized in that, In step S4, the working space of the tire cap support assembly (13) is a 2m clearance between the lower chord of the steel roof grid and the top of the reusable standard section assembly (12). The main crane is equipped with a secondary boom as an aerial boom extension, which works in conjunction with the auxiliary crane to complete the aerial relay hoisting, transforming the high-altitude welding and assembly operation into a ground pre-assembly operation.

8. The construction method according to claim 5, characterized in that, In step S5, after the pedestrian walkway module (2) is installed, the maximum deflection of the walkway is no greater than 1 / 250 of its span.

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