Construction method of long-span roof truss

Abstract

The present application relates to the technical field of truss construction, and discloses a large-span roof truss construction method, which comprises the following steps: constructing a ground and a foundation for temporarily supporting a jig frame; constructing a permanent support frame and a temporary support jig frame in a preset area; completing ground segmented assembly of a roof longitudinal supporting truss and a roof transverse main truss in the preset area according to a design; hoisting each segment of a preset number of roof longitudinal supporting trusses on the permanent support frame and the temporary support jig frame arranged in the longitudinal direction, and then hoisting a preset number of roof transverse main trusses on the roof longitudinal supporting truss and a plurality of temporary support jig frames arranged in the transverse direction; repeating the foregoing steps from the position of the third roof transverse main truss; after the hoisting of the roof transverse main trusses is completed, synchronously unloading the temporary support jig frame in sections and grades; and finally removing the temporary support jig frame. The construction method can efficiently complete the construction of a large-span roof truss under the condition that the site is limited, thereby shortening the construction period.

Description

Technical Field

[0001] This invention relates to the field of truss construction technology, specifically to a method for constructing a large-span roof truss. Background Technology

[0002] To ensure functionality, large-span hangar roof projects typically employ large-span space frame or truss structures for the upper roof, with frame support systems on both sides and in the middle. The underground portion serves as a utility tunnel for logistics and transportation. This structural system is characterized by its large span, heavy load, and complex spatial relationships, placing high demands on construction techniques.

[0003] In actual construction, the aforementioned structure was constrained by site conditions. The presence of underground pipe trenches and logistics channels severely limited the ground bearing capacity, making it impossible to employ efficient construction methods such as integral sliding or integral lifting. Existing construction techniques typically require large crawler cranes to directly construct the roof trusses on the ground slab. Due to the large span of the trusses, the numerous lifting segments, and the complexity of the procedures, coupled with the interdependence between these procedures, construction efficiency is low, the construction period is long, and the economic costs are high.

[0004] Regarding the control of truss installation accuracy, large-span roof trusses are subject to the combined effects of their own weight, temperature changes, and construction loads. If the support system design is unreasonable or the installation sequence is improper, it can easily lead to large deflection deformation of the truss, affecting the overall structural performance and installation accuracy. Currently, existing technologies lack systematic solutions for handling the layout of temporary support frames, the installation sequence of truss segments, and unloading processes, making it difficult to balance construction efficiency and structural safety. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a construction method for large-span roof trusses, which can efficiently complete the construction of large-span roof trusses even under limited site conditions, thereby shortening the construction cycle.

[0006] According to one embodiment of the present invention, a construction method for a large-span roof truss is provided, comprising the following steps: S1, a construction ground level and a foundation for a temporary support frame; S2, a permanent support frame for a pre-defined construction area and the temporary support frame, wherein the temporary support frame is arranged between horizontally adjacent permanent support frames and between longitudinally adjacent permanent support frames; S3, according to the design segmentation requirements, assembling the roof longitudinal support truss and the roof transverse main truss in the pre-defined area on the ground in segments; S4, hoisting the pre-defined number of segments of the roof longitudinal support truss onto the permanent support frame and the temporary support frame arranged longitudinally. On the supporting frame, adjacent roof longitudinal truss segments are connected together. Then, a predetermined number of roof transverse main trusses are hoisted onto the roof longitudinal trusses and several temporary supporting frames set along the transverse direction. Adjacent roof transverse main truss segments are connected together. S5. Starting from the position of the third roof transverse main truss, repeat steps S2 to S4. In this case, along the construction direction, the construction of steps S2 and S3 in front is carried out simultaneously with the construction of step S4 in the rear. S6. After the roof transverse main trusses are hoisted, the temporary supporting frames are unloaded synchronously in sections and grades, and finally the temporary supporting frames are removed.

[0007] As one implementation method, in step S1, when constructing the floor, embedded parts are set at the preset temporary support frame installation positions. After the concrete pouring of the floor slab is completed, the position of the embedded parts is checked and cured according to the design requirements. A conversion beam is welded on the embedded parts, and the conversion beam is provided with bolt holes for bolt connection with the temporary support frame.

[0008] As one implementation method, in step S2, after each permanent support frame and temporary support frame is completed, its structure is corrected and its nodes are fixed; after the permanent support frame and temporary support frame in the preset area are installed, the dimensions, elevation and verticality of the overall structure are checked.

[0009] As one implementation method, the construction of the temporary support frame includes: connecting the main limb and the lacing strip together to form a support frame, bolting a support beam to the upper end of the support frame, welding a support column on the support beam, setting a support pad on the support column, and bolting the lower end of the support frame to the conversion beam.

[0010] As one implementation method, in step S3, after all truss weld joints in the preset area are welded, non-destructive testing is performed. After the non-destructive testing is qualified, the truss assembly is reviewed as a whole. Only after confirming that it meets the installation accuracy requirements can the subsequent hoisting process begin.

[0011] In one implementation, after the longitudinal support trusses of multiple roofs are hoisted in sequence in step S4, the connecting members between the longitudinal support trusses of adjacent roofs are constructed to complete the node fixing.

[0012] As one implementation method, in step S4, after the longitudinal support truss of the roof passes the acceptance test, the installation of the transverse main truss of the roof is carried out. The two ends of the transverse main truss of the roof are fixed to the permanent support frame, and the middle segment joints are connected on the temporary support frame. Each connection node is fixed according to the design requirements. Among them, each segment of the transverse main truss of the roof is installed simultaneously on both sides of the longitudinal support truss of the roof according to the principle of symmetrical construction.

[0013] As one implementation method, in step S5, when constructing the roof transverse main truss starting from the position of the third roof transverse main truss, each segment of the adjacent roof transverse main truss is installed in a multi-point parallel manner, and the segments of the adjacent roof transverse main trusses are constructed simultaneously with longitudinal staggered arrangement. The number of roof transverse main trusses constructed simultaneously and in an overlapping manner does not exceed three.

[0014] As one implementation method, in step S6, the temporary support frame is unloaded synchronously in four stages: the first unloading is 25% of the deflection value, the second unloading is 50% of the deflection value, the third unloading is 75% of the deflection value, and the fourth unloading is 100% of the deflection value.

[0015] As one implementation method, each time the temporary support frame is unloaded, it is done in the manner of unloading from the middle to the sides and sequentially along the construction direction.

[0016] Based on the above description and practice, the large-span roof truss construction method of the present invention solves the installation difficulties of the roof longitudinal supporting trusses and the roof transverse main trusses under limited space by coordinating the staggered and sequential construction of the roof longitudinal supporting trusses and the roof transverse main trusses, as well as the multi-point parallel sequential construction of the roof transverse main trusses. This significantly shortens the construction period and achieves the effect of cost reduction and efficiency improvement. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the installation of the longitudinal roof support truss in a large-span roof truss construction method according to one embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the installation of the transverse main truss of the roof in a construction method for a large-span roof truss according to one embodiment of the present invention.

[0019] Figure 3 This is a schematic diagram of the installation of a temporary support frame in a construction method for a large-span roof truss according to one embodiment of the present invention.

[0020] Figure 4This is a plan view of the temporary support frames in a construction method for a large-span roof truss according to an embodiment of the present invention.

[0021] Figure 5 This is a schematic diagram of the roof and its supporting structure during construction in a large-span roof truss construction method according to one embodiment of the present invention.

[0022] The attached figures are labeled as follows: 1. Ground floor; 2. Temporary support frame; 3. Permanent support frame; 4. Roof longitudinal support truss; 5. Roof transverse main truss; 21. Main member; 22. Tie strip; 23. Support beam; 24. Support column; 25. Support pad; 26. Transfer beam. Detailed Implementation

[0023] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be more comprehensive and complete, and will fully convey the concept of exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0024] Furthermore, the accompanying drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. It should be noted that in this disclosure, the terms "comprising," "configured with," and "set in" are used to indicate an open-ended inclusion, meaning that additional elements / components / etc. may exist besides those listed; the terms "first," "second," etc., are used only as labels and are not intended to limit the number or order of objects; the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0025] Unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] like Figures 1 to 5 As shown in this embodiment, a construction method for a large-span roof truss is disclosed. This method mainly addresses the installation efficiency problem of large-span hangar roof space truss structures under limited construction site conditions. By setting up a temporary support frame 2 and adopting a multi-point parallel flow construction process, the installation operations of the roof longitudinal supporting truss 4 and the roof transverse main truss 5 are coordinated and organized, thereby improving construction efficiency. The main structures involved in this construction method are: temporary support frame 2, permanent support frame 3, roof longitudinal supporting truss 4, and roof transverse main truss 5.

[0027] The specific steps for constructing this large-span roof truss are as follows: Step S1: Construction of the foundation for the ground slab and temporary support frame.

[0028] Before constructing the ground slab (1), finite element simulation analysis technology was used to perform strength, stiffness, and stability calculations on the entire roof truss installation process, including the crawler crane hoisting the ground slab, the temporary support frame (2), the roof longitudinal support truss (4), and the roof transverse main truss (5), to ensure the safety and controllability of the construction process. Through finite element simulation analysis, the structural stress state at each construction stage was clarified, and the layout and load-bearing capacity of the temporary support frame (2) were determined, ensuring safe construction thereafter.

[0029] Specifically, in this step, before pouring the concrete for the roof slab, embedded parts are installed at the pre-set installation positions of the temporary support frame 2. The planar position deviation and elevation deviation of the embedded parts should meet the relevant specifications. After the roof slab concrete is poured, concrete curing is carried out according to design requirements to ensure the concrete strength reaches the design standard. After curing, the position and elevation deviation of the embedded parts are checked to confirm compliance with specifications.

[0030] H-beam transfer beams 26 are welded onto the embedded parts. The lower part of the transfer beam 26 is fully welded to the embedded parts. After welding, the weld quality is inspected to ensure that the weld quality is qualified. The transfer beam 26 is provided with bolt holes for bolting to the temporary support frame 2, so that the temporary support frame 2 can be fixed to the transfer beam 26 with high-strength bolts to form a stable support foundation structure. The installation of the transfer beam 26 not only ensures the reliable transfer of the load of the temporary support frame 2 to the ground structure, but also facilitates the installation and subsequent dismantling of the temporary support frame 2, improving the convenience and safety of construction.

[0031] Step S2: Construct the permanent support frame 3 and temporary support frame 2 in the pre-set construction area. The temporary support frame 2 is set between the horizontally adjacent permanent support frames 3 and between the vertically adjacent permanent support frames 3.

[0032] After completing the foundation construction of the ground floor and temporary support frame, the installation of the permanent support frame 3 within the pre-designated area was organized according to the principle of segmented and continuous construction, while the installation of the temporary support frame 2 was completed simultaneously. The permanent support frame 3 includes steel columns, steel beams, and supporting structures on both sides and in the middle of the roof.

[0033] For the construction of permanent support frame 3, the steel columns, steel beams, and support structures were installed sequentially according to the design drawings. After each permanent support frame 3 was installed, structural correction and joint fixing were carried out in a timely manner to ensure that each permanent support frame 3 formed an independent and stable structural unit.

[0034] For the construction of temporary support frame 2, such as Figure 3 As shown, the temporary support frame 2 adopts a lattice structure with good stability and is set at the ground slab below the roof truss segment, providing reliable support for the construction of the large-span roof space truss. The roof truss load is transferred to the ground structure through the bottom transfer beam 26 of the temporary support frame 2, and then to the foundation. The temporary support frame 2 consists of main members 21, tie rods 22, support beams 23, support columns 24, support pads 25, and transfer beams 26. The specific construction process is as follows: the main members 21 and tie rods 22 are connected together with high-strength bolts to form a lattice support frame. The support beams 23 are bolted to the upper end of the support frame, and the support columns 24 are welded to the support beams 23. Support pads 25 are set on the support columns 24. The support pads 25 are placed on the support columns 24 for easy and flexible placement and removal, and for cutting and adjustment during later unloading. The lower end of the support frame is bolted to the transfer beams 26 with high-strength bolts to form a complete temporary support frame 2 system.

[0035] High-strength bolts are used to connect the main member 21 to the lacing strip 22, the main member 21 to the support beam 23, and the support frame to the transfer beam 26, to facilitate dismantling after construction. The support beam 23 and the support column 24 are connected by welding to ensure rigid force transmission at this node. Figure 4 As shown, the temporary support frame 2 is arranged in the roof plane according to the design requirements, and is set between the horizontally adjacent permanent support frames 3 and the vertically adjacent permanent support frames 3 to form a multi-point support system for the roof truss.

[0036] After each permanent support frame 3 or temporary support jig 2 is installed, its structure must be promptly corrected and its joints fixed to ensure the installation accuracy of each component. Once all permanent support frames 3 and temporary support jigs 2 in the pre-designed area are installed, the dimensions, elevation, and verticality of the overall structure must be thoroughly checked to confirm compliance with design requirements before proceeding to the next stage.

[0037] Step S3: According to the design segmentation requirements, complete the ground segmentation assembly of the roof longitudinal support truss 4 and the roof transverse main truss 5 in the preset area.

[0038] After completing the construction of the permanent support frame 3 and temporary support frame 2 in the pre-designed area, the roof longitudinal truss 4 and the roof transverse main truss 5 are assembled on the ground in the designated assembly area according to the design segmentation requirements. The geometric dimensions, node positions and welding quality of each segment must be strictly controlled during the ground assembly.

[0039] During assembly, an assembly jig is set up on the ground, and the position of each member is precisely controlled according to the design dimensions and shape of the truss segments. After each member is positioned, welding is carried out at all joints according to the welding process specifications, and the welding sequence and welding parameters are strictly controlled to reduce the impact of welding deformation on assembly accuracy.

[0040] After all truss welds in the pre-designated area are completed, a professional testing organization will conduct non-destructive testing (NDT) and issue a test report. Any substandard welds will be repaired, and then retested until the NDT results are satisfactory. NDT primarily includes methods such as ultrasonic testing and magnetic particle testing, and the inspection pass rate must meet the requirements of the design documents.

[0041] After passing the flaw detection inspection, the assembled truss is comprehensively reviewed. The main inspection items include: deviations in the overall length, height, and width of the truss; deviations in node coordinates; straightness of chords and web members; and flatness of the end faces of assembled sections. Only after confirming that all dimensional deviations meet the installation accuracy requirements can the subsequent hoisting process begin. Assembled truss sections should be properly protected to prevent deformation or damage during transportation and stacking.

[0042] Step S4: Hoisting and installation of the roof longitudinal supporting truss 4 and the roof transverse main truss 5. Hoist the predetermined number of roof longitudinal supporting truss segments 4 onto the permanent support frame 3 and the temporary support jigs 2 set along the longitudinal direction. Connect adjacent roof longitudinal supporting truss segments 4 together. Then hoist the predetermined number of roof transverse main truss 5 onto the roof longitudinal supporting truss 4 and several temporary support jigs 2 set along the transverse direction. Connect adjacent roof transverse main truss segments 5 together.

[0043] After the ground assembly is completed and passes inspection, the hoisting and installation of the roof longitudinal supporting truss 4 and the roof transverse main truss 5 will commence. This step is divided into two stages: the hoisting and installation of the roof longitudinal supporting truss 4 and the hoisting and installation of the roof transverse main truss 5.

[0044] During the hoisting and installation phase of the roof longitudinal support truss 4, crawler cranes were used to hoist each segment of the roof longitudinal support truss 4. Before hoisting, a safety inspection of the hoisting machinery and lifting equipment was conducted to confirm that the hoisting parameters met the hoisting requirements. Figure 1As shown, the pre-set number of roof longitudinal support truss 4 segments are hoisted in sequence. One end of the longitudinal support truss 4 is fixed to the top support of the permanent support frame 3, and the other end is fixed to a designated position above the temporary support frame 2 set along the longitudinal direction. Adjacent roof longitudinal support truss 4 segments are connected together by node plates and high-strength bolts to ensure that the node connection is firm.

[0045] After the longitudinal trusses 4 of the roof are hoisted in sequence, the connecting members between adjacent longitudinal trusses 4 should be constructed in a timely manner. The nodes should be fixed according to the design requirements to form a stable system of longitudinal trusses 4. The stress state of the system should be checked to ensure that it meets the design requirements. The timely installation of the connecting members can ensure the overall stability of the longitudinal trusses 4 of the roof. It must be completed and accepted before the installation of the transverse main trusses.

[0046] After the longitudinal supporting truss 4 of the roof has passed the acceptance inspection, the installation of the transverse main truss 5 of the roof will commence. For example... Figure 2 As shown, the transverse main truss 5 of the roof is divided into two major sections with four joints. One end of the transverse main truss 5 is fixed to the permanent support frame 3, and the middle section joint is connected to the temporary support frame 2 set along the transverse direction. Each connection node is fixed according to the design requirements, and finally connected to the corbel side of the longitudinal support truss 4 of the roof.

[0047] Each segment of the transverse main truss 5 of the roof is installed simultaneously on both sides of the longitudinal supporting truss 4 of the roof, following the principle of symmetrical construction. The construction progress and installation accuracy on both sides are strictly controlled to ensure uniform stress on the structure and prevent the longitudinal supporting truss 4 of the roof from tilting due to uneven stress on both sides. After installation, the overall position and stress state of the truss are checked to confirm that it meets the design requirements.

[0048] Step S5: Multi-point parallel flow alternating construction.

[0049] like Figure 5 As shown, starting from the location of the third roof transverse main truss 5, steps S2 to S4 are repeated to achieve multi-point parallel construction. In this step, along the construction direction, the construction of steps S2 and S3 at the front is carried out simultaneously with the construction of step S4 at the rear, thereby making full use of construction space and hoisting machinery, avoiding waiting between processes, and improving overall construction efficiency.

[0050] Specifically, starting from the location of the third roof transverse main truss 5, when constructing the roof transverse main truss 5, each segment of adjacent roof transverse main trusses 5 is installed in parallel at multiple points, with the segments of adjacent roof transverse main trusses 5 being constructed simultaneously with longitudinal staggered alignment. This staggered installation method means that at the same time, different roof transverse main trusses 5 are at different stages of installation progress, with each hoisting machine operating simultaneously in different positions without interference, maximizing the utilization efficiency of the hoisting machinery. The number of roof transverse main trusses 5 under simultaneous cross-construction does not exceed three to ensure structural stress balance and overall stability during construction, preventing uneven stress on both sides of the roof longitudinal supporting truss 4 and excessive overall deformation caused by simultaneous construction of multiple trusses.

[0051] During the multi-point parallel construction process, after the installation of every two roof transverse main trusses 5 is completed, the secondary trusses and tie rods between the roof transverse main trusses 5 are promptly installed to complete the node fixation and ensure that a stable structural system can be formed after each step of construction is completed. The above process is repeated until all roof transverse main trusses 5, secondary trusses, and tie rods are installed in place and adjusted to the design position, completing the overall assembly and hoisting of the roof trusses.

[0052] Throughout the multi-point parallel construction process, the roof truss structure needs to be monitored in real time. The main monitoring contents include the displacement and deflection of key truss nodes and the stress state of temporary support frame 2. If any abnormality is detected in the monitoring data, construction must be stopped immediately, the cause analyzed, and corresponding measures taken. Construction can only continue after safety is confirmed.

[0053] Step S6: Temporary support frame 2 is unloaded and removed synchronously in sections and grades.

[0054] After all the main roof trusses have been hoisted and passed overall acceptance, the temporary support frame 2 will be unloaded synchronously in sections and at different levels, and finally the temporary support frame 2 will be dismantled. Before unloading, a comprehensive unloading stress analysis must be conducted on all temporary support frames 2, a detailed section-by-section synchronous unloading plan must be formulated, the unloading sequence, unloading ratio and technical requirements of each frame must be clearly defined, and the plan must be submitted to the design unit for review and confirmation.

[0055] The temporary support frame 2 was unloaded synchronously in four large cycles, divided into two sections. The first cycle unloaded 25% of the deflection, the second 50%, the third 75%, and the fourth 100%. Unloading was achieved by uniformly and proportionally cutting the support columns 24, strictly controlling the deflection value at each stage to ensure a smooth transfer of structural load during the unloading process.

[0056] In this embodiment, taking a total of 45 sets of temporary support frames 2 as an example, each large-cycle unloading is carried out in the manner of unloading from the middle to the sides and sequentially along the construction direction. The specific unloading sequence is as follows: The first step is to simultaneously unload the corresponding deflection values ​​of the temporary support frames TJ-16 to TJ-18 located in the middle area where the roof was constructed first; The second step involves symmetrically and synchronously unloading the corresponding deflection values ​​on both sides of the temporary support frames TJ-1 to TJ-7 and TJ-31 to TJ-37 located in the areas where the roof was constructed first. The third step involves simultaneously unloading the corresponding deflection values ​​from temporary support frames TJ-19 to TJ-30 located in the middle extension area of ​​the roof construction. The fourth step involves symmetrically and synchronously unloading the corresponding deflection values ​​on both sides of the temporary support frames TJ-8 to TJ-15 and TJ-38 to TJ-45 in the extended areas on both sides of the roof construction.

[0057] The four large-cycle unloading was completed sequentially as described above, with real-time monitoring of the roof truss's deformation, displacement, and stress changes throughout the process. If any abnormalities were detected in the monitoring data, unloading was immediately stopped, emergency measures were implemented, and the cause was analyzed and resolved before unloading could continue. The unloading sequence, starting with the middle and then moving to the sides, fully utilized the structure's symmetry, ensuring uniform deformation during unloading and preventing asymmetrical stress caused by asynchronous unloading on both sides, thus guaranteeing the structural safety of the roof truss during the unloading process.

[0058] After unloading, a comprehensive review of the overall position and deformation of the roof truss was conducted to confirm that it met the design and specification requirements and that the structural stress had reached the design state.

[0059] After unloading and acceptance, a specific dismantling plan for temporary support frame 2 was formulated, specifying the dismantling sequence, machinery selection, and safety protection measures. Following the principle of dismantling from the inside out and from top to bottom, temporary support frame 2 was dismantled in sections and areas. During the dismantling process, strict measures must be taken to prevent collisions or disturbances to the completed roof truss structure. Dismantled components were promptly cleaned and transported, and on-site civilized construction was maintained. After completion, the ground and surrounding area were cleaned and restored, and embedded parts were handled according to design requirements.

[0060] This construction method for large-span roof trusses involves setting up temporary support frames 2, supporting multiple points, and installing the roof's transverse main trusses 5 in parallel. Utilizing limited space, it coordinates the staggered and sequential construction of the roof's longitudinal supporting trusses 4 and transverse main trusses 5, as well as the multi-point parallel sequential construction of the transverse main trusses 5. This solves the installation difficulties of the roof's longitudinal supporting trusses 4 and transverse main trusses 5 under site constraints, significantly shortening the construction period and achieving cost reduction and efficiency improvement.

[0061] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A construction method for a large-span roof truss, characterized in that, Includes the following steps: S1, the foundation of the construction site and temporary support frame; S2, a permanent support frame for the pre-designed construction area and a temporary support frame, wherein the temporary support frame is arranged between horizontally adjacent permanent support frames and between vertically adjacent permanent support frames; S3. According to the design segmentation requirements, complete the ground segmentation assembly of the roof longitudinal support truss and the roof transverse main truss in the preset area; S4. Hoist the pre-set number of roof longitudinal support truss segments onto the permanent support frame and the temporary support frame set along the longitudinal direction, and connect adjacent roof longitudinal support truss segments together. Then hoist the pre-set number of roof transverse main trusses onto the roof longitudinal support truss and several temporary support frames set along the transverse direction, and connect adjacent roof transverse main truss segments together. S5. Starting from the location of the third roof transverse main truss, repeat steps S2 to S4. Along the construction direction, the construction of steps S2 and S3 in front and the construction of step S4 in the back are carried out simultaneously. S6. After the main transverse truss of the roof is hoisted, the temporary support frame will be unloaded in sections and at different levels in a synchronized manner, and finally the temporary support frame will be removed.

2. The construction method for a large-span roof truss as described in claim 1, characterized in that, In step S1, when constructing the floor, embedded parts are set at the preset temporary support frame installation positions. After the concrete pouring of the floor slab is completed, the position of the embedded parts is checked and cured according to the design requirements. A transfer beam is welded on the embedded parts, and the transfer beam is provided with bolt holes for bolt connection with the temporary support frame.

3. The construction method for a large-span roof truss as described in claim 1, characterized in that, In step S2, after each permanent support frame and temporary support frame is completed, its structure is corrected and its nodes are fixed; after the permanent support frame and temporary support frame in the preset area are installed, the dimensions, elevation and verticality of the overall structure are checked.

4. The construction method for a large-span roof truss as described in claim 2, characterized in that, The temporary support frame for construction includes: connecting the main limbs and the lacing strips together to form a support frame, bolting a support beam to the upper end of the support frame, welding a support column to the support beam, setting a support pad on the support column, and bolting the lower end of the support frame to the conversion beam.

5. The construction method for a large-span roof truss as described in claim 1, characterized in that, In step S3, after all truss weld joints in the preset area are welded, non-destructive testing is performed. After the non-destructive testing is qualified, the truss assembly is reviewed as a whole. Only after confirming that it meets the installation accuracy requirements can the subsequent hoisting process begin.

6. The construction method for a large-span roof truss as described in claim 1, characterized in that, In step S4, after the longitudinal support trusses of multiple roofs are hoisted in sequence, the connecting members between the longitudinal support trusses of adjacent roofs are constructed to complete the node fixing.

7. The construction method for a large-span roof truss as described in claim 6, characterized in that, In step S4, after the longitudinal truss of the roof passes inspection, the installation of the transverse main truss of the roof is carried out. The two ends of the transverse main truss of the roof are fixed to the permanent support frame, and the middle segment joints are connected on the temporary support frame. Each connection node is fixed according to the design requirements. Among them, each segment of the transverse main truss of the roof is installed simultaneously on both sides of the longitudinal truss of the roof according to the principle of symmetrical construction.

8. The construction method for a large-span roof truss as described in claim 1, characterized in that, In step S5, starting from the location of the third roof transverse main truss, when constructing the roof transverse main truss, each segment of the adjacent roof transverse main truss adopts a multi-point parallel installation method, and the segments of the adjacent roof transverse main trusses are staggered longitudinally and constructed simultaneously. The number of roof transverse main trusses constructed simultaneously and crosswise does not exceed three.

9. The construction method for a large-span roof truss as described in claim 1, characterized in that, In step S6, the temporary support frame is unloaded synchronously in four stages: the first stage unloads 25% of the deflection value, the second stage unloads 50% of the deflection value, the third stage unloads 75% of the deflection value, and the fourth stage unloads 100% of the deflection value.

10. The construction method for a large-span roof truss as described in claim 9, characterized in that, Each time the temporary support frame is unloaded, it should be done in the order of first the middle and then the sides, and in sequence along the construction direction.

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