Composite truss system roof structure construction process and roof structure manufactured by process

Abstract

The invention belongs to the technical field of steel structure buildings, and discloses a composite truss system roof structure construction process and a roof structure manufactured by the process, and the process comprises the following steps: assembling and forming a single box type bending and twisting section: manufacturing a bending and twisting single plate and assembling and forming the bending and twisting section; manufacturing a triangular truss; solid web girders are manufactured; assembling and welding the plane pipe truss; subgrade box manufacturing; and simulating assembly. The main structure is of a triangular space truss structure arranged in an oblique crossing mode, various loads of the roof structure are effectively borne, and the safety and stability of the structure are guaranteed; based on oblique primary trusses, triangular trusses and secondary structures between skylight common unit columns, solid web girders are adopted, the characteristics of the primary trusses and the secondary structures are combined, the overall structure is optimized, and the overall performance of the structure is improved. And material waste is reduced through the standard manufacturing process, and the manufacturing cost is reduced. The size precision and the butt joint accuracy of all the components are ensured through simulated assembly, component alignment connection can be carried out more smoothly during field installation, the adjustment time in the field installation process is shortened, and the construction efficiency is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of steel structure building, and particularly relates to a composite truss system roof structure construction process and a roof structure manufactured by the process. BACKGROUND

[0002] The Shanghai East Station of the East Hub is located in Zhuzhao Town, Pudong New Area, and is a new large comprehensive transportation hub integrating national railway, urban railway, urban rail transit and other transportation functions. The station building and related projects are divided into three functional areas of the main station building, canopy area and throat area according to the different building function forms. The composite truss system roof structure of the main station of the Shanghai East Station adopts a triangular space truss structure arranged in a skew direction, forming a stable vertical and horizontal force transmission system. The upper chord and web members of the triangular truss adopt hot-rolled round pipes, and the lower chord structure is exposed and extends to the main structure-flower column. Based on the inclined main truss, the secondary structure between the ordinary unit columns of the skylight adopts a solid web beam, and the web part is treated by opening holes according to the building flower texture direction. The secondary structure between the vertical columns of the skylight unit adopts a dense rib tie rod, and the tie rod also serves as a glass system purlin.

[0003] The composite truss system roof structure is a three-dimensional truss modeling, which meets the functional and aesthetic needs of large-span and complex space buildings, but its structural characteristics also bring many challenges to manufacturing and construction. The triangular truss, the "feather" solid web beam, the support member and other structural types are various, and the local structure involves complex structures such as bending and torsion joints, and a large number of space site docking, which requires strict control of the structure processing precision, and any deviation may affect the stability of the whole structure. The composite truss system roof structure is complex and has many component site docking ports, which is a manifestation of the technical strength of heavy steel structure manufacturing units, and is also a cost and efficiency control difficulty.

[0004] The construction process of a super-large-span fish belly type roof truss disclosed in the related reference CN113789909A includes the following steps: assembling a jig frame; checking the appearance size of each part of each component before assembly and welding, and correcting the appearance size that exceeds the tolerance; folding the straight web and the inclined web; manufacturing and folding the lower chord and the upper chord; manufacturing and folding the support node; finally, assembling and welding the lower chord, the support node, the upper chord, the straight web and the inclined web; and assembling and welding the stiffener plate and the connecting plate. Each component is divided into parts, all part plates are cut by numerical control layout and cutting, and numerical control plasma cutting is preferentially used to reduce the deformation caused by cutting. The support node is assembled by a positive integral assembly method to ensure that the manufacturing precision of the single component meets the requirements of on-site assembly and design. The connection and welding between each component are performed in different ways according to the structural characteristics and the needs of later installation and bearing, thereby optimizing the construction process. However, for the composite truss system roof structure, the abutment effect of this construction process is poor, and the construction efficiency is relatively low. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a composite truss system roof structure construction process which can accurately control the positions of each rod during assembly, ensure the dimensional accuracy of the structural parts, reduce costs, and improve construction efficiency, and a roof structure manufactured by the process.

[0006] To solve the above technical problems, the present application provides a composite truss system roof structure construction process, which comprises: Single box type bending and torsion section assembly forming The bending and torsion section assembly forming comprises bending and torsion single plate manufacturing. The bending and torsion single plate manufacturing comprises the following steps: Step A: obtaining a body development drawing by pre-rolling a rough shape and locally bending and controlling the shape; Step B: forming a process 3D coordinate lofting drawing according to the bending and torsion of the panel; Step C: drawing a sample and erecting a panel forming jig frame according to the process 3D coordinate lofting drawing; Step D: processing and forming the panel by rolling and pressing, and comparing the processed and formed panel with the jig frame, and then flowing to the next process if the size is qualified; Triangular truss manufacturing The upper chord rod I is a circular tube, the lower chord rod I is a box type structure, and the local part is a bending and torsion box type, and the inclined strut is a circular tube. The manufacturing comprises the following steps: Step one, ground sample layout; Step two, making the tire frame; Step three, placing the separately made upper chord bar I, lower chord bar I on the tire frame, and preventing welding shrinkage allowance; Step four, after positioning the upper chord bar I and lower chord bar I of the triangular truss, sequentially assembling the straight web member and the inclined web member; using temporary plate spot welding to fix adjacent members, positioning and welding each member; pre-welding shrinkage allowance and installation gap; Step five, assembling one side of the triangular truss; after ensuring that the triangular truss has sufficient strength, turning over; Step six, after turning over the triangular truss, completing the welding of the other side of the triangular truss and the upper chord purlin substructure; Step seven, after welding is completed, back to the tire for inspection, and auxiliary use of total station instrument to inspect the spatial dimension data of the member; Step eight, after inspection and correction are qualified, marking the butt joint at each site member connection position of the triangular truss; finally, completing the allowance cutting and beveling of each member port with the triangular truss center as the reference, and then disassembling the triangular truss along the site butt joint position; Finally, enter the next coating process; Fabrication of solid web beam Comprising the following steps: Step a, bending and twisting single board fabrication, step b, selecting bending and twisting single board outer contour control points according to the model, process layout, forming 3D coordinate erection assembly tire frame, step c, assembling the first side beam web on the tire frame, step d, assembling the lower bending and twisting section I, step e, covering the other side beam web, completing the welding between the solid web beam stiffener and the two side beam webs, step f, assembling the remaining solid web beam stiffener, covering the two side flanges, turning over after ensuring that the member has sufficient strength, step g, after turning over, completing the welding of the other side main weld, as well as the upper chord purlin substructure welding, step h, after welding is completed, back to the tire for inspection, and auxiliary use of total station instrument to inspect the spatial dimension data of the member, step i, fixed length, cutting allowance, and opening the site bevel according to the end layout coordinate data, step j, assembling and welding other parts according to the requirements; Four, flat tube truss assembly and welding; Five, subgrade box fabrication; Six, simulation assembly In the semi-finished product link, the total station instrument is measured at each site butt joint port of single rod member or multiple members, and matched with the design model.

[0007] By adopting the technical scheme, the main direction structure adopts the triangular space truss structure arranged in a skew manner, forms a stable vertical and horizontal force transmission system, can effectively bear various loads of the roof structure, and guarantees the safety and stability of the structure; based on the skew main truss triangular truss, the ordinary unit column secondary structure between the skylights adopts a solid web beam, combines the characteristics of the main truss and the secondary structure, optimizes the overall structure, and improves the overall performance of the structure. The standardized manufacturing process is beneficial to reducing material waste and reducing manufacturing cost. In the manufacturing process, the jig is manufactured according to the accurate lofting data, the position of each member can be accurately controlled in the assembly process, a reasonable welding shrinkage allowance and installation gap are pre-lofted, material cutting errors or rework caused by size deviation are avoided, material waste is reduced, and material cost is reduced. Through a reasonable welding process, the welding deformation is effectively controlled, the size accuracy of the structural member is ensured, secondary correction or re-manufacturing is avoided, and rework cost is reduced. The simulation assembly ensures the size accuracy and butt accuracy of each component, and the component alignment and connection can be more smoothly carried out during on-site installation, the adjustment time in the on-site installation process is reduced, and the construction efficiency is improved.

[0008] Preferably, when the bending and twisting single board is manufactured, a modeling software is used to convert the original edge line of the bending and twisting single board into a plurality of bending arc lines, the steel is preliminarily shaped in a bending arc manner, and then a bending equipment is used for local shape control.

[0009] By adopting the technical scheme, the original edge line of the bending and twisting single board is accurately converted into a plurality of bending arc lines by using a modeling software, accurate data basis is provided for subsequent processing, the digital conversion mode avoids errors that may be caused by manual measurement and drawing, the preliminary shaping and local shape control of the steel can be strictly performed according to design requirements, the size accuracy of the bending and twisting single board is greatly improved, and the bending and twisting single board can meet the accurate requirements of the building structure.

[0010] Preferably, when the triangular truss is manufactured, the pipe intersection of the truss structure is cut by using a pipe numerical control five-dimensional or six-dimensional intersection line cutting machine, a welding groove is directly formed during cutting, and a groove root area is lofted and formed.

[0011] By adopting the technical scheme, the pipe numerical control five-dimensional or six-dimensional intersection line cutting machine can realize automatic operation, only needs to input the designed three-dimensional model data into the cutting machine control system, and can automatically and accurately cut the complex curve shape of the pipe intersection, so that the cut intersection is highly consistent with the theoretical design shape, and the welding accuracy is improved.

[0012] Preferably, the bending and twisting segment assembly forming includes the following steps: Step one, considering the section height, selecting one side of the web plate to be placed on the jig; selecting three points of the outer contour to form a horizontal plane, establishing a projection horizontal plane, and then performing component lofting; Step two, set up the cradle with the exception of both ends, and put a process partition in the middle according to the soft file, and it can be used only after passing the inspection; Step three, take the contour of one end as the reference, place the one side web plate on the cradle, adjust the position, and make the web plate adhere to the cradle in the natural bending arc state; Step four, assemble the partition through lofting data; assemble from the middle to both sides; Step five, assemble and weld the gasket plate on the web plate, and perform the positioning welding; the positioning weld adopts the intermittent weld of the gas shielded welding; Step six, sequentially assemble the upper wing plate, the other side web plate, weld the partition after assembling into a U shape; adopt the heating and pressurizing method in the local position to make the body adhere to the partition in the natural bending arc state; pre-inspect and correct the U-shaped structure; perform the ultrasonic flaw detection on the concealed weld, and cover the plate after passing the inspection; Step seven, remove the garbage in the U-shaped groove, assemble and position weld the lower wing plate; Step eight, symmetrically weld the body weld; the welded bending and torsion section is subjected to UT inspection according to the requirements; Step nine, after the welding is completed, perform the back cradle inspection, and assist in using the total station to inspect the spatial dimension data of the component; the length allowance is reserved for the subsequent assembly; Step ten, assemble and weld the lug plate and the connecting plate according to the requirements; perform the appearance finishing, remove the welding scar, spatter, and polish to be smooth, including cutting the edge of the exposed component; after passing the inspection, send to the next process.

[0013] Through the above series of accurate assembly and welding processes, the connection between the components of the box-type bending and torsion section component is firm and tight, the component can uniformly transmit stress when bearing load, the overall load-bearing capacity and stability of the component are improved. At the same time, reasonable process control reduces the residual stress in the component, reduces the risk of deformation and cracking of the component in the use process, and prolongs the service life of the component. The standardized process flow facilitates the operation and mastery of workers, reduces the blindness and randomness in the production process, and improves the production efficiency.

[0014] Preferably, the planar pipe truss assembly and welding process flow is as follows: Step one, make the assembly cradle; Step two, integrally assemble the upper chord II, the lower chord II, and the tapered transition section on the cradle and pre-position the shrinkage allowance; Step three, sequentially assemble and weld the main pipe and the branch pipe from the middle to both sides; Step four, turn over the truss, complete the welding of the weld on the other side, and then position and install the welding of the truss purlin.

[0015] Through the above technical scheme, the upper chord II, the lower chord II, the main pipe, and the branch pipe are firmly connected through reasonable assembly and welding sequence and turning operation, forming an organic whole, and improving the structural stability and safety of the planar pipe truss.

[0016] Preferably, in step three of the planar tubular truss assembly and welding process, the welding adopts the principle of main pipe and branch pipe on one node: ① the round pipe with the largest diameter is the main pipe; or ② when the pipe diameter is the same, the vertical web member is the main pipe; when the adjacent main pipe has been assembled and welded, resulting in the branch pipe being unable to be assembled, the branch pipe is segmented and the splicing length is ≥600mm.

[0017] By adopting the above technical solution, with the main pipe having the largest diameter, the main force path of the structure is transmitted through the main pipe when it is under load, which is more in line with mechanical principles and ensures the stability and safety of the structure under various loads. The vertical web members, acting as the main pipe, work together with the upper chord II and lower chord II to form a stable geometric system that resists lateral deformation of the structure. Reasonable branch pipe segmentation and splicing lengths ensure the strength and stability of the branch pipe splicing points.

[0018] Preferably, the roadbed box fabrication includes the following steps: a. welding the hemisphere to the roadbed box stiffening plate, b. covering the bottom plate, c. assembling the four roadbed box round tubes, d. assembling the roadbed box stiffening plate II sequentially from the inside out, e. covering the roadbed box top plate and completing the welds between the roadbed box top plate and the roadbed box stiffening plate I, roadbed box stiffening plate II, and roadbed box round tubes, f. removing the side plates.

[0019] By adopting the above technical solution, the assembly of four roadbed box cylindrical tubes forms a spatial frame structure, which possesses high rigidity and stability. The mutual support and constraint between the roadbed box cylindrical tubes effectively resist forces in various directions, improving the roadbed box's resistance to deformation. Compared with planar structures, spatial frame structures can better adapt to complex load conditions. Following the steps sequentially in the assembly operation of the roadbed boxes helps improve production efficiency and ensures the strength of the roadbed box structure.

[0020] The composite truss system roof structure, manufactured using the construction process of a composite truss system roof structure, includes triangular trusses, solid-web beams, planar tubular trusses, top chord purlins, and a roadbed box. Triangular trusses are installed at each of the four corners of the roadbed box. Several solid-web beams are installed between two triangular trusses on one side of the roadbed box via a back beam. Top chord purlins are installed on the top of the solid-web beams and are fixedly connected to the triangular trusses. The bottom of the solid-web beams is installed on the column top plate. The lower chord members (I) of the triangular trusses are fixedly installed at the four corners of the column top plate. The corbels at both ends of the back beam are connected to the lower chord members (I) of the triangular trusses on both sides. Box-type beams are installed on the lower chord members (I) of the four triangular trusses. Planar tubular trusses are installed between pairs of triangular trusses on the other three sides of the roadbed box, and the ends of the planar tubular trusses are fixedly connected to the ends of the triangular trusses.

[0021] By adopting the above technical solution, triangular trusses are installed at the four corners of the roadbed box, providing a basic spatial support framework for the entire roof structure. Solid-web beams are installed between the two triangular trusses on one side of the roadbed box, and planar tubular trusses are installed between pairs of triangular trusses on the other three sides of the roadbed box. This creates a stable connection system for the entire roof structure in multiple directions, effectively resisting various external forces. The upper chord purlins and triangular trusses are fixedly connected, the bottom of the solid-web beams is installed on the column top plate, and the lower chord members I of the triangular trusses are fixedly installed at the four corners of the column top plate, making the entire roof structure an organic whole. The roof structure is stable; under load, the components work together to jointly bear and transfer the load, avoiding structural damage caused by local stress concentration, and the overall load-bearing capacity of the structure is strong.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The main structure of this invention adopts a diagonally arranged triangular spatial truss structure, forming a stable vertical and horizontal force transmission system that can effectively withstand various loads on the roof structure, ensuring structural safety and stability. Based on the diagonally arranged triangular main truss, the secondary structure between the columns of the skylight ordinary unit uses solid web beams, combining the characteristics of the main truss and the secondary structure, optimizing the overall structure, and improving the overall structural performance. A standardized manufacturing process helps reduce material waste and manufacturing costs. During manufacturing, a jig is made based on precise layout data, and the position of each member can be accurately controlled during assembly. Reasonable welding shrinkage allowances and installation gaps are pre-set, avoiding material cutting errors or rework due to dimensional deviations, thus reducing material waste and costs. A reasonable welding process effectively controls welding deformation, ensuring the dimensional accuracy of structural components, avoiding secondary corrections or remanufacturing, and reducing rework costs. Simulated assembly ensures the dimensional accuracy and docking accuracy of each component, allowing for smoother component alignment and connection during on-site installation, reducing adjustment time during on-site installation, and improving construction efficiency.

[0023] 2. When assembling a single box-shaped bending and twisting segment in this invention, considering the cross-sectional height, one side of the box web plate 1 is selected and placed on the jig; three points of the outer contour are selected to form a horizontal plane, and a projected horizontal plane is established. Then, the component is laid out. The laying out method based on precise geometric relationships and projection principles is adopted to accurately convert the design dimensions into the shape and position of the component in actual production, laying the foundation for the accurate assembly of subsequent components and effectively reducing the component size deviation caused by laying out errors.

[0024] 3. The present invention features triangular trusses installed at the four corners of the roadbed box, providing a basic spatial support framework for the entire roof structure. Solid-web beams are installed between two triangular trusses on one side of the roadbed box, and planar tubular trusses are installed between pairs of triangular trusses on the other three sides of the roadbed box. This creates a stable connection system for the entire roof structure in multiple directions, effectively resisting various external forces. The upper chord purlins are fixedly connected to the triangular trusses, the bottom of the solid-web beams is installed on the column top plate, and the lower chord members I of the triangular trusses are fixedly installed at the four corners of the column top plate, making the entire roof structure an organic whole. The roof structure is stable; under stress, the components work together to share and transfer loads, avoiding structural damage caused by localized stress concentration, resulting in a strong overall load-bearing capacity. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the present invention; Figures 2-4 This is a schematic diagram illustrating the fabrication process of the bent and twisted veneer of this invention. Figures 5-11 This is a schematic diagram of the assembly of the bending and twisting sections of the present invention; Figures 12-15 This is a schematic diagram illustrating the fabrication of the triangular truss of the present invention; Figures 16-21 This is a schematic diagram of the fabrication of the solid web beam of the present invention; Figures 22-27 This is a schematic diagram of the assembly and welding of the planar tubular truss of the present invention; Figures 28-33 This is a schematic diagram illustrating the fabrication of the roadbed box of the present invention.

[0026] Drawing numbers: 1. Box web, 2. Diaphragm, 3. Upper flange, 4. Lower flange, 5. Upper chord I, 6. Lower chord I, 7. Diagonal brace, 8. Upper chord purlin, 9. Beam web, 10. Bending-torsion section I, 11. Flange, 12. Straight web member, 13. Diagonal web member, 14. Upper chord II, 15. Lower chord II, 16. Tapered transition section, 17. Main pipe, 18. Branch pipe, 19. Hemisphere, 2 0. Roadbed box girder plate I, 21. Bottom plate, 22. Roadbed box circular tube, 23. Roadbed box top plate, 24. Side plate, 25. Triangular truss, 26. Solid web beam, 27. Planar tube truss, 28. Roadbed box, 29. Column top plate, 30. Back beam, 31. Corbel, 32. Box girder, 33. Solid web beam girder plate, 34. Roadbed box girder plate II, 35. Bending and twisting section II, 36. U-rib. Detailed Implementation

[0027] like Figure 1 As shown, a typical composite truss roof structure consists of a triangular truss 25, a feather-like solid-web beam 26, a roadbed box girder 28, a planar tubular truss 27, and an upper chord purlin 8. Due to the large three-dimensional dimensions and height of the composite truss roof structure, a processing scheme of "individual fabrication of each component + overall simulated pre-assembly" is adopted.

[0028] In the entire design, the triangular truss 25 is pre-disassembled and manufactured separately, mainly consisting of a circular tube upper chord I5, a straight box-shaped lower chord, a bent-torsted lower chord II, and a diagonal circular tube brace 7. The assembly process is carried out only after each component is completed. The "feather-like" solid-web beam 26 is divided into a large-plane upper section beam web 9 and a lower section bent-torsted I10. The large-plane upper section is directly manufactured on the assembly jig, while the bent-torsted I10 is manufactured separately before entering the final assembly stage. Since the circular tubes 22 at the four corners of the roadbed box 28 connect to the lower chord of the triangular truss 25, and the lower hemisphere 19 is connected to the lower chord I6 of the triangular truss 25 via diagonal braces, to ensure the dimensional accuracy of the roadbed box 28 as much as possible, it is chosen to be assembled together with one pair of diagonal triangular trusses 25.

[0029] Furthermore, in truss structures, the quality of the circular tube intersection line cutting is crucial, particularly in designing the intersection bevels in the toe, side, transition, and root areas to achieve effective weld area in different zones and ensure equal strength connections. To guarantee truss fabrication quality and on-site installation accuracy, the circular tube intersections in truss structures are cut using a CNC five-dimensional or six-dimensional circular tube intersection line cutting machine. The welding bevel is directly created during the machine cutting process, while the root area is laid out.

[0030] Both the lower chord I6 and the solid web beam 26 of the triangular truss contain bending and torsion members. The dimensional accuracy of the assembly of these individual members determines the success of the subsequent final assembly stage. Furthermore, the accuracy of the bending and forming of the individual plates during the fabrication of these bending and torsion members directly affects the final AESS (Advanced Embedded System) effect. Therefore, the selection of the appropriate design and the control of fabrication precision are particularly important for this part.

[0031] For single-plate bending and twisting, there are two common pressing processing schemes based on the modeling characteristics. The first is the pressing and bending method based on Tekla modeling. In Tekla modeling, the bending and twisting plate is made by splicing and fitting a series of triangular plates. The edges of adjacent triangular plates become the "natural" indentation positions during forming. However, the indentations are obvious when pressed by a hydraulic press, and there are more areas for subsequent heat straightening, making it only suitable for components with low appearance requirements. The second is the pressing method based on Rhino modeling. Rhino's bending and twisting single plates are composed of multiple spatial curved surfaces, with a very smooth overall linearity. It can be pressed using simple spatial coordinates. However, the bending and twisting are still formed by pressing through a series of steps, resulting in more obvious fold marks. This method is suitable for components with higher appearance requirements.

[0032] The two conventional solutions mentioned above are not the best solutions for components with AESS appearance requirements. Therefore, the "pre-rolled prototype + local bending control" method is proposed. That is, the steel is pre-bent and initially shaped, and then local bending control is carried out using bending equipment. Its advantages are that the indentation is shallow and the bending position is small. The steel surface is still relatively smooth and natural after processing, which is more advantageous in the field of AESS component processing.

[0033] The "pre-rolled prototype + local bending control" method also has its advantages in processing the machining drawing. While the two conventional pressing methods only require a machining drawing with indentation coordinates, the contour is still a spatial curve composed of broken lines. The new method, however, requires a machining drawing based on multiple fitted arcs. Its advantages are twofold: firstly, the spatial arcs obtained through fitting curves are closer to the original contour; secondly, the contour edge of the bent / torsted part is a spatial curve. Based on Rhino's characteristics, multi-order reconstructed curves and arc fitting are performed in three-dimensional space, converting the original edge line into multiple arc segments, allowing the processed arc line to deviate from the original edge line by less than 2mm.

[0034] In addition, Rhino software was used for secondary optimization of the solid, the body plane of each curved component was unfolded, and the edge shaping angle was added according to the cross-sectional shape of the single plate at different positions. The impact on the AESS surface was considered from the source, and the cross-sectional accuracy of the assembly was improved.

[0035] Construction technology for composite truss roof structures includes: Single box-shaped bending and twisting segment assembly molding: The lower chord I6 of the triangular truss 25 and the solid web beam 26 in this project both have box-shaped bending and torsion sections. The main body material is cut into irregular shapes and pre-bent using a hydraulic press before use. Furthermore, the entire process of component processing and manufacturing (detailing, assembly, and inspection) requires control using three-dimensional coordinates. Coordinates for individual parts and the overall assembly will be issued in the form of notification slips. Each step in the processing must be strictly performed according to three-dimensional coordinates, with rigorous self-inspection, mutual inspection, and specialized inspection.

[0036] The layout line for the single box-type bend and twist section shall be laid out according to the component layout drawing. The jig shall be arranged and adjusted, and the levelness of the jig shall be controlled within ±1.0mm. The jig shall also have sufficient strength, rigidity and height, and shall be inspected and approved by the quality management department before use.

[0037] The bending and twisting veneer is made as follows: like Figures 2-4 As shown, taking the web 9 of a solid-web beam as an example: Step A: Obtain the unfolded diagram of the main body by using a pre-rolled prototype and local bending control method.

[0038] Step B: Based on the bending and twisting of the panel, create a 3D coordinate layout diagram for the process.

[0039] Step C: Based on the 3D coordinate layout drawing of the process, draw the site pattern and then erect the panel forming jig, such as... Figure 2 .

[0040] Step D: The panel is processed into beam web 9 by rolling and pressing. The processed panel (beam web 9) is compared with the jig. After the dimensions are qualified, it flows into the next process, such as... Figure 3 If the body has U-rib 36, then weld the U-rib 36 in this step, such as... Figure 4 .

[0041] The bending and twisting section is assembled as follows: like Figures 5-11 As shown, taking the lower chord I6 of the triangular truss 25 as an example, the welding of the bending and twisting section II35 includes the following steps: Step 1, such as Figure 5 Considering the cross-sectional height, one side of the box web plate 1 is placed on the jig; three points of the outer contour are selected to form a horizontal plane, and a projected horizontal plane is established for component layout; a layout method based on precise geometric relationships and projection principles is adopted to accurately convert the design dimensions into the shape and position of the components in actual production, laying the foundation for the accurate assembly of subsequent components and effectively reducing component size deviations caused by layout errors.

[0042] Step Two, as follows Figure 6 In addition to the jigs at both ends, a process partition is placed at the soft stop in the middle to set up the jig, and it can only be used after passing inspection. When the original spacing of the partitions 2 is greater than 3m, a 16mm process partition is installed at the easily deformable soft stop between the two partitions 2 to control the cross-sectional deformation. A uniform and reasonable jig layout can provide stable and reliable support for the box-shaped bending and twisting section II35 component, ensuring that the component maintains the correct spatial posture during the assembly and forming process, preventing deformation caused by insufficient or uneven support, thereby improving the overall accuracy of the component.

[0043] Step 3, as follows Figure 7 Using the outline of one end as a reference, place one side of the box web plate 1 flat on the tire frame, adjust its position so that the box web plate 1 is in a natural curved state and closely adheres to the tire frame.

[0044] Step 4, as follows Figure 8 The partition 2 is assembled using the layout data, proceeding from the center outwards. A 0.5mm welding shrinkage allowance is added to each partition 2 to compensate for welding shrinkage deformation between the partition and the main body along their length. By precisely controlling the allowance, the position and dimensions of the assembled partition 2 meet the design requirements, further improving the assembly accuracy of the components.

[0045] Step 5: Assemble the welding backing plate on the box web 1 and perform tack welding; the tack welds are made by intermittent gas shielded welding, with a weld length of 60mm and a spacing of 300mm. Clearly specify the weld length and spacing to ensure the quality of the tack welds, provide a stable connection foundation for the formal welding, and avoid component displacement or deformation during the welding process due to weak tack welds or poor weld quality.

[0046] Step Six, as Figure 9 The upper wing plate 3 and the other side of the box web plate 1 are assembled sequentially to form a U-shape, after which the partition plate 2 is welded. Local heating and pressurization are used to ensure the body adheres tightly to the partition plate 2 in a natural curved state, which helps improve the fusion quality of the weld joint and reduces welding defects. The U-shaped structure undergoes pre-inspection and correction; attention is paid to ultrasonic testing of concealed welds, which can promptly detect internal defects such as porosity, slag inclusions, and cracks, ensuring that the weld quality meets standard requirements and improving the overall structural strength and reliability of the component. Only after passing inspection can the cover plate be installed.

[0047] Step 7, as follows Figure 10 Remove the debris from the U-shaped groove, and assemble and position the lower wing plate 4.

[0048] Step 8: Symmetrically weld the main body welds to balance the heat and stress generated during welding, reduce deformation caused by uneven heating in certain areas, and ensure the geometric dimensional and shape accuracy of the components. The main welds of the box-type column should be welded according to the following... Figure 11 Welding should be performed in the sequence shown (1→2→3→4). The welded bent and twisted section II35 should undergo UT inspection as required.

[0049] Step 9: After welding is completed, return the assembly to the mold for inspection, and use a total station to check the spatial dimensions of the components; the length allowance is reserved for subsequent final assembly.

[0050] Step 10: Assemble and weld the ear plates, connecting plates, and other parts as required; perform external finishing, remove weld spatter and spatter, and polish the surface, including the cut edges of exposed components; after passing inspection, send it to the next process.

[0051] Through the above series of precise assembly and welding processes, the connections between the various components of the box-type bending and torsion section are ensured to be firm and tight, enabling the component to uniformly transfer stress when bearing loads, thereby improving the overall load-bearing capacity and stability of the component. At the same time, reasonable process control reduces residual stress inside the component, lowering the risk of deformation and cracking during use and extending the service life of the component. Standardized process flows are easy for workers to operate and master, reducing blind and arbitrary aspects in the production process and improving production efficiency.

[0052] The triangular truss 25 is fabricated as follows: The upper chord I5 is a round tube, the lower chord I6 is a box-shaped structure, and locally it is a bent-twisted box-shaped structure. The diagonal brace 7 is a round tube. Looking at the overall structure of the roof, in order to reduce the shrinkage deformation of the triangular truss 25 during assembly, the welding sequence of the intersecting branch pipes 18 and corbels 31 has no effect. The chords are made separately and then assembled as a whole by the triangular truss 25.

[0053] like Figures 12-15 As shown, the fabrication of the triangular truss 25 includes the following steps: Step 1, such as Figure 12 Based on the model data, land sample layout is carried out.

[0054] Step Two, as follows Figure 13 Establish a reasonable and stable jig, and only use the jig after it has passed inspection. The jig should be set to avoid truss nodes and must provide sufficient welding space for the welder. Arrange and adjust the jig, with a spacing of 500mm between each jig. The levelness of the jig must be controlled within ±1.0mm, and the jig must have sufficient strength, rigidity, and height. It must be inspected and approved by the quality management department before use.

[0055] Step 3, as follows Figure 14 The separately manufactured upper chord I5 and lower chord I6 are placed on the jig, and welding shrinkage allowance is prevented. Step 4: After the upper chord I5 and lower chord I6 of the triangular truss 25 are correctly positioned, assemble the straight web members 12 and diagonal web members 13 in sequence. Adjacent members are fixed with temporary support plates by spot welding. Position and weld each member (upper chord I5, lower chord I6, straight web member 12, diagonal web member 13). Pay attention to pre-allowing welding shrinkage allowance and installation gaps. Through steps such as site layout and jig fabrication, a precise benchmark is provided for truss fabrication. During assembly, the straight and diagonal web members 13 are assembled in sequence, fixed with temporary support plates by spot welding, and attention is paid to pre-allowing welding shrinkage allowance and installation gaps to ensure accurate positioning of each member and improve the quality of truss fabrication.

[0056] Step 5, as follows Figure 15 Assemble one side of the triangular truss 25; ensure the triangular truss 25 has sufficient strength before turning it over; install the port parts last, and use a total station for inspection and positioning to ensure the port size and shape.

[0057] Step 6: After the triangular truss 25 is flipped over, complete the welding on the other side of the triangular truss 25 and the 8 structural weldings of the upper chord purlin; Step 7: After welding is completed, return the mold for inspection and use a total station to check the spatial dimensions of the components. Step 8: After inspection and correction, mark the connection points of each on-site component of the triangular truss 25 with alignment marks to facilitate on-site alignment and installation. Finally, using the center of the triangular truss 25 as a reference, complete the excess cutting and beveling of each member's ends, and then disassemble the triangular truss 25 along the on-site connection points. Finally, proceed to the next painting process. Marking the connection points of each on-site component of the truss with alignment marks, completing the excess cutting and beveling of each member's ends, and then disassembling along the on-site connection points facilitates on-site alignment and installation, improving construction efficiency.

[0058] To reduce the shrinkage deformation during assembly of the triangular truss 25, the chord members were fabricated separately and then assembled as a whole. By rationally planning the manufacturing process, welding deformation was effectively controlled, ensuring the dimensional accuracy of the truss.

[0059] When fabricating the triangular truss 25, the circular tube intersections of the truss structure are cut using a CNC five-dimensional or six-dimensional circular tube intersection cutting machine. The welding bevel is directly created during the cutting process, and the root area of ​​the bevel is laid out. The CNC five-dimensional or six-dimensional circular tube intersection cutting machine can achieve automated operation. Simply input the designed three-dimensional model data into the cutting machine's control system, and it can automatically and accurately cut out the complex curve shape of the circular tube intersection, ensuring a high degree of consistency between the cut intersection and the theoretical design shape, thus improving welding accuracy.

[0060] Fabrication of solid web beams.

[0061] The twisted segment I10 of the solid-web beam 26 resembles a feather. Its width is 200mm, and its height varies from 2700mm to 800mm. (Example:) Figures 16-21 As shown, the fabrication steps for solid web beam 26 are as follows: Step a: Fabrication of bent and twisted veneer.

[0062] During the fabrication of bent and twisted veneer panels, modeling software is used to convert the original edges of the panels into multiple curved lines. The steel is pre-shaped to its initial curved form, and then bending equipment is used for localized shaping. The precise conversion of the original edges into multiple curved lines using modeling software provides an accurate data foundation for subsequent processing. This digital conversion method avoids errors that may arise from manual measurement and drawing, ensuring that the initial shaping and localized shaping of the steel strictly adhere to design requirements. This significantly improves the dimensional accuracy of the bent and twisted veneer panels, ensuring they meet the precise requirements of the building structure.

[0063] Step b, as follows Figure 16 , 17 Based on the model, select the outer contour control points of the bending and twisting single plate, carry out the process layout, and form a 3D coordinate assembly frame.

[0064] Step c, as Figure 18 First, assemble the first side beam web plate 9 on the jig.

[0065] Step d, as follows Figure 19 Assemble the lower bending and twisting section I10.

[0066] Step e, as Figure 20 Cover the other side of the beam web 9, and complete the weld between the solid web beam stiffening plate 33 and the two side beam webs 9.

[0067] Step f, as follows Figure 21 Assemble the remaining solid web beam stiffening plate 33 and cover the two side flanges 11; ensure that the components have sufficient strength before turning them over.

[0068] Step g: After flipping over, complete the welding of the main weld on the other side and the 8 structural welding of the upper chord purlin.

[0069] Step h: After welding is completed, return the mold for inspection and use a total station to check the spatial dimensions of the components.

[0070] Step i: Determine the length, cut the allowance, and create an on-site bevel based on the end layout coordinate data.

[0071] Step j: Install and weld the ear plates and connecting plates as required. Perform external finishing, remove weld spatter and weld spatter, and grind the surface smooth, including the cut edges of exposed components. After passing inspection, proceed to the next process. After welding, return to the formwork for inspection. Use a total station to verify the spatial dimensions of the components, determine the cutting allowance, and create on-site beveling based on the end layout coordinates. Finally, install and weld other parts as required, ensuring the dimensional accuracy and processing quality of the solid web beam 26.

[0072] Planar tubular truss assembly and welding.

[0073] like Figures 22-27 As shown, the assembly and welding process of planar tubular truss 27 is as follows: A) As Figure 22 First, draw the outline of the planar truss drawing from the top view on the ground, as well as the positioning center lines and baselines of each component, and mark the key control points.

[0074] B) such as Figure 23 Then, the assembly jig is fabricated according to the ground alignment. After fabrication, the top of the jig should be level within ±1mm, and the jig should have sufficient strength, rigidity, and height. The jig must pass inspection before use. The jig should be positioned to avoid truss nodes and should provide sufficient welding space for the welder. Positioning reference lines and center lines for the components are marked on the jig, with a +3mm allowance between the upper and lower chords. Necessary positioning supports are then installed.

[0075] C) such as Figure 24The upper chord II14, lower chord II15, and tapered transition section 16 are assembled as a whole, hoisted onto the jig, and pre-positioned with a 1 / 2000mm shrinkage allowance. When positioning the upper chord II14 and lower chord II15 of the planar tubular truss 27, align them with the center line, baseline, and outer contour line of the upper chord II14 and lower chord II15 on the ground, while controlling the fit between their ends and the ground position and their horizontal height. If there is any deviation at the control point, it must be corrected by fire (lifting point difference ≤2mm). After the positioning is correct and meets the design requirements, it is firmly spot welded to the jig.

[0076] D) As Figure 25 , 26 The main pipe 17 and branch pipe 18 are welded sequentially from the middle to both sides, with the main pipe 17 welded first and the branch pipe 18 welded next. Before turning over, the planar tubular truss 27 must be ensured to have sufficient strength. The principle of using a main pipe 17 and branch pipe 18 at a single node is as follows: ① The circular pipe with the largest diameter is the main pipe 17. Using the largest diameter as the main pipe 17 ensures that the main force path is transmitted through the main pipe 17 when the structure is under load, which is more in line with mechanical principles and ensures the stability and safety of the structure under various loads. Or ② When the pipe diameter is the same, the vertical web member is the main pipe 17. The vertical web member, as the main pipe 17, works together with the upper chord member II 14 and the lower chord member II 15 to form a stable geometric system and resist the lateral deformation of the structure. If the branch pipe 18 cannot be assembled because the adjacent main pipe 17 has already been welded, the branch pipe 18 can be segmented, with a splicing length ≥ 600mm. Reasonable segmentation and splicing length of the branch pipe 18 can ensure the strength and stability of the splicing part of the branch pipe 18.

[0077] E) such as Figure 27 The truss is then flipped over to complete the welding on the other side. This flipping operation allows the welder to weld in the optimal welding posture, avoiding weld quality defects such as porosity, slag inclusions, and incomplete fusion caused by poor welding positions, thus improving the internal and external quality of the weld. Next, the truss purlin supports are positioned, installed, and welded. Through a reasonable welding sequence and flipping operation, the various components, such as the upper chord II14, lower chord II15, main pipe 17, and branch pipe 18, are firmly connected to form an organic whole, improving the structural stability and safety of the planar tubular truss 27.

[0078] After welding is completed, the weld is inspected using a mold and a total station is used to verify the spatial dimensions of the components. Once the inspection is passed, the excess material at the weld ends is trimmed. 100mm crosshair positioning marks are hammered into the connection points of each of the 27 on-site ports of the planar tubular truss to facilitate on-site alignment and installation.

[0079] After the entire planar tubular truss 27 is fabricated and passes inspection, temporary supports are used to reinforce the on-site joint openings of the upper and lower chords of the planar tubular truss 27 according to the actual situation, so as to prevent the planar tubular truss 27 from deforming during relocation and transportation and affecting on-site installation.

[0080] V. Construction of roadbed boxes.

[0081] like Figures 28-33 As shown, all welds on the roadbed box structure are CP-1. The fabrication of the roadbed box 28 includes the following steps: a. As... Figure 28 The hemisphere 19 is welded to the roadbed box girder I 20. Welding the hemisphere 19 helps distribute the upper load and avoids localized stress concentration. The roadbed box girder I 20 further strengthens the connection between the hemisphere 19 and the surrounding structure, improving the strength and stiffness of this part. b. For example... Figure 29 , base plate 21. c. such as Figure 30 Four circular tubes 22 are assembled into the roadbed box 28. The assembly of these four circular tubes forms a spatial frame structure for the roadbed box 28, which possesses high rigidity and stability. The mutual support and constraint between the circular tubes 22 effectively resist forces in various directions, improving the deformation resistance of the roadbed box 28. Compared to planar structures, spatial frame structures are better able to adapt to complex load conditions. d. For example... Figure 31 Assemble the roadbed box girder II 34 sequentially from the inside out. e. For example Figure 32 Cover the top plate 23 of the roadbed box, and complete the welds between the top plate 23 of the roadbed box and the roadbed box stiffening plate I 20, the roadbed box stiffening plate II 34, and the roadbed box circular pipe 22. f. As Figure 33 Remove and install side panels 24. Following the manufacturing steps of the roadbed box 28, the assembly process will improve production efficiency and ensure the structural strength of the roadbed box 28.

[0082] Simulated assembly.

[0083] Physical component inspection not only consumes significant manpower, material resources, transportation, and site resources, but also places higher demands on project schedule management. To improve efficiency and simultaneously check the connection status of components, digital inspection is employed. Digital inspection eliminates the need for hoisting and movement, allowing for visualized data comparison on a computer for more intuitive observation and analysis. It also saves space, offers high safety, reduces costs, shortens the construction period, and avoids component deformation caused by repeated hoisting. Therefore, to ensure smooth on-site installation, factory digital inspection is conducted on the main structure of the prototype.

[0084] In the semi-finished product stage, total station measurements are performed on all on-site connection ports of single rods or multiple components, and the measurements are matched with the design model. Simulated assembly is used to identify and resolve potential dimensional deviations and connection problems in advance, ensuring smooth on-site installation and improving overall construction quality and efficiency.

[0085] The main structure of this application adopts a diagonally arranged triangular space truss structure, forming a stable vertical and horizontal force transmission system that can effectively withstand various loads of the roof structure, ensuring structural safety and stability. Based on the diagonal main truss triangular truss 25, the secondary structure between the skylight ordinary unit columns adopts a solid web beam 26, combining the characteristics of the main truss and the secondary structure, optimizing the overall structure and improving the overall structural performance. A standardized manufacturing process helps reduce material waste and manufacturing costs. During manufacturing, a jig is made based on precise layout data, and the position of each member can be accurately controlled during assembly. Reasonable welding shrinkage allowances and installation gaps are pre-set, avoiding material cutting errors or rework due to dimensional deviations, thus reducing material waste and costs. A reasonable welding process effectively controls welding deformation, ensuring the dimensional accuracy of structural components, avoiding secondary corrections or remanufacturing, and reducing rework costs. Simulated assembly ensures the dimensional accuracy and docking accuracy of each component, allowing for smoother component alignment and connection during on-site installation, reducing adjustment time during on-site installation and improving construction efficiency.

[0086] The composite truss system roof structure, manufactured using the construction process of a composite truss system roof structure, includes triangular trusses 25, solid-web beams 26, planar tubular trusses 27, top chord purlins 8, and a roadbed box 28. Triangular trusses 25 are installed at each of the four corners of the roadbed box 28. Several solid-web beams 26 are installed between two triangular trusses 25 on one side of the roadbed box 28 via a back beam 30. Top chord purlins 8 are installed on the top of the solid-web beams 26, and the top chord purlins 8 are fixedly connected to the triangular trusses 25. The bottom of the 26 is installed on the column top plate 29; the lower chord I6 of the triangular truss 25 is fixedly installed at the four corners of the column top plate 29; the corbels 31 at both ends of the back beam 30 are connected to the lower chord I6 of the triangular truss 25 on both sides, and box beams 32 are installed on the lower chord I6 of the four triangular trusses 25; a planar tube truss 27 is installed between each pair of triangular trusses 25 on the other three sides of the roadbed box 28, and the ends of the planar tube truss 27 are fixedly connected to the ends of the triangular trusses 25. The triangular trusses 25 installed at the four corners of the roadbed box 28 in this application provide a basic spatial support frame for the entire roof structure. A solid web beam 26 is installed between two triangular trusses 25 on one side of the roadbed box 28, and a planar tube truss 27 is installed between each pair of triangular trusses 25 on the other three sides of the roadbed box 28, so that the entire roof structure forms a stable connection system in multiple directions, effectively resisting various external forces. The top chord purlin 8 and the triangular truss 25 are fixedly connected. The bottom of the solid web beam 26 is installed on the column top plate 29. The bottom chord members I6 of the triangular truss 25 are fixedly installed at the four corners of the column top plate 29, making the entire roof structure an organic whole. The roof structure is stable. When under stress, the components can work together to jointly bear and transfer the load, avoiding structural failure caused by local stress concentration. The overall load-bearing capacity of the structure is strong.

[0087] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. Construction technology of composite truss system roof structure, characterized by: include, Single box-shaped bending and twisting segment assembly molding This includes the fabrication of bent and twisted veneers and the assembly of bent and twisted sections. The steps for making bent and twisted veneer are as follows: Step A: Obtain the unfolded drawing of the main body by pre-rolling the prototype and controlling the shape by local bending; Step B: Create a 3D coordinate layout drawing based on the bending and twisting of the panel; Step C: Draw a pattern based on the 3D coordinate layout drawing and then set up the panel forming jig; Step D: Process the panel into shape by rolling and pressing. Compare the processed panel with the jig. If the dimensions are qualified, it will flow into the next process. Triangular truss fabrication The upper chord I is a round tube, the lower chord I is a box-shaped structure with some bent and twisted box-shaped sections, and the diagonal brace is a round tube; the fabrication includes the following steps: Step 1: Site layout; Step 2: Fabrication of the jig; Step 3: Place the separately fabricated upper chord I and lower chord I on the jig, ensuring sufficient welding shrinkage allowance; Step 4: After the upper chord I and lower chord I of the triangular truss are correctly positioned, assemble the straight web members and diagonal web members in sequence; use temporary support plates for spot welding to fix adjacent members, position and weld each member; pre-set welding shrinkage allowance and installation gap; Step 5: Assemble one side of the triangular truss; ensure the triangular truss has sufficient strength before flipping it over; Step 6: After flipping the triangular truss, complete the welding on the other side of the triangular truss and the secondary structure of the upper chord purlin; Step 7: After welding, return to the jig for inspection, and use a total station to verify the spatial dimensions of the components; Step 8: After inspection and correction, mark the connection points of each component on site; finally, using the center of the triangular truss as a reference, complete the excess cutting and beveling of each member's ends, and then disassemble the triangular truss along the on-site connection points; finally, proceed to the next painting process; Solid web beam fabrication Includes the following steps: Step a) Fabrication of the bent-twisted single-layer plate; Step b) Based on the model, select the outer contour control points of the bent-twisted single-layer plate, perform process layout, and form a 3D coordinate assembly frame; Step c) First, assemble the web of the first side beam on the frame; Step d) Assemble the lower bent-twisted section I; Step e) Cover the web of the other side beam, and complete the weld between the solid web beam stiffener and the webs of both sides; Step f) Assemble the remaining solid web beam stiffener, cover the flanges on both sides, and turn the component over after ensuring sufficient strength; Step g) After turning over, complete the welding of the main weld on the other side and the welding of the upper chord purlin secondary structure; Step h) After welding, return to the frame for inspection, and use a total station to check the spatial dimension data of the component; Step i) Determine the length, cut the allowance, and open the on-site beveling according to the end layout coordinate data; Step j) Weld other parts as required. IV. Welding of planar tubular trusses; V. Construction of roadbed boxes; VI. Simulated Assembly In the semi-finished product stage, total station measurements are performed on each on-site connection port of a single rod or multiple components, and the measurements are matched with the design model.

2. The construction process of the composite truss system roof structure according to claim 1, characterized in that: During the fabrication of the bent and twisted veneer, modeling software is used to convert the original edge lines of the bent and twisted veneer into multiple curved lines. The steel is pre-shaped by bending, and then local shaping is controlled using a bending press.

3. The construction process of the composite truss system roof structure according to claim 1, characterized in that: When the triangular truss is fabricated, the circular tube intersection of the truss structure is cut using a circular tube CNC five-dimensional or six-dimensional intersection line cutting machine, and the welding bevel is directly opened during the cutting process, with the root area of ​​the bevel laid out.

4. The construction process of the composite truss system roof structure according to claim 1, characterized in that: The assembly and forming of the bent and twisted segments includes the following steps: Step 1: Considering the cross-sectional height, select one side of the box web plate and place it on the jig; select three points on the outer contour to form a horizontal plane, establish the projected horizontal plane, and then lay out the component; Step 2: In addition to setting up the jigs at both ends, place a process partition in the middle at the soft block to set up the jigs, and only use them after they pass the inspection. Step 3: Using the outline of one end as a reference, place one side of the box web plate flat on the jig frame and adjust its position so that the box web plate is in a natural curved state and closely adheres to the jig frame. Step 4: Assemble the partitions using the layout data; assemble from the middle outwards. Step 5: Assemble the welding backing plate on the box web and perform tack welding; the tack weld is welded by intermittent gas shielded welding. Step 6: Assemble the upper wing plate and the other side of the box web plate in sequence, and weld the partition after assembling into a U-shape; use local heating and pressurization to make the body fit tightly against the partition in a natural arc state; conduct pre-inspection and correction of the U-shaped structure; perform ultrasonic testing on the concealed welds, and cover the plate after it passes the test. Step 7: Remove debris from the U-shaped groove, assemble and position the lower wing plate; Step 8: Symmetrically weld the main body welds; perform UT inspection on the welded bent and twisted sections as required; Step 9: After welding is completed, perform a final inspection using the mold and a total station to verify the spatial dimensions of the components; retain the length allowance for subsequent final assembly. Step 10: Install and weld the ear plates and connecting plates as required; perform external finishing, remove weld spatter and spatter, and polish the surface, including the cut edges of exposed components; after passing inspection, send the product to the next process.

5. The construction process of the composite truss system roof structure according to claim 1, characterized in that: The assembly and welding process of the planar tubular truss is as follows: Step 1: Make the assembly frame; Step 2: Assemble the upper chord II, lower chord II, and tapered transition section as a whole, hoist them onto the jig, and pre-addition shrinkage allowance for positioning; Step 3: Weld the main pipe and branch pipes sequentially from the middle to both sides; Step 4: Turn the truss over, complete the welding of the other side, and then position and weld the truss purlin brackets.

6. The construction process of the composite truss system roof structure according to claim 5, characterized in that: In step three of the planar truss assembly and welding process, the welding adopts the principle of main pipe and branch pipe on one node: ① the round pipe with the largest diameter is the main pipe; or ② when the pipe diameter is the same, the vertical web member is the main pipe; when the adjacent main pipe has been assembled and welded, the branch pipe cannot be assembled, the branch pipe is segmented and the splicing length is ≥600mm.

7. The construction process of the composite truss system roof structure according to claim 1, characterized in that: The fabrication of the roadbed box includes the following steps: a. welding the hemisphere to the roadbed box stiffening plate I, b. covering the bottom plate, c. assembling the four roadbed box round tubes, d. assembling the roadbed box stiffening plate II sequentially from the inside out, e. covering the roadbed box top plate and completing the welds between the roadbed box top plate and the roadbed box stiffening plate, the roadbed box round tube I, and the roadbed box round tube II, f. removing the side plates.

8. A composite truss system roof structure manufactured according to the construction process of the composite truss system roof structure according to any one of claims 1-7, comprising triangular trusses, solid web beams, planar tubular trusses, top chord purlins, and a roadbed box. Triangular trusses are installed at each of the four corners of the roadbed box. Several solid web beams are installed between two triangular trusses on one side of the roadbed box via a back beam. Top chord purlins are installed on the top of the solid web beams and are fixedly connected to the triangular trusses. The bottom of the solid web beams is installed on the column top plate. The bottom chord members I of the triangular trusses are fixedly installed at the four corners of the column top plate. The corbels at both ends of the back beam are connected to the bottom chord members I of the triangular trusses on both sides. Box-type small beams are installed on the bottom chord members I of the four triangular trusses. Planar tubular trusses are installed between the two triangular trusses on the other three sides of the roadbed box, and the ends of the planar tubular trusses are fixedly connected to the ends of the triangular trusses.

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