Installation method for high-altitude roof cantilever steel structure

Abstract

The invention discloses a mounting method for a high-altitude roof cantilever steel structure, belongs to the technical field of engineering construction, and is mainly used for mounting the high-altitude roof cantilever steel structure. The technical problem to be solved by the invention is to provide the mounting method for the overhanging steel structure of the high-altitude roof. The mounting method comprises the following steps: step 1, mounting a mounting frame below the mounting position of the overhanging steel structure; secondly, the cantilever steel structure is hoisted to the mounting frame in a segmented mode; thirdly, the supporting adjusting columns are cut, and the height of the cantilever steel structure is adjusted; fourthly, the cantilever steel structure and the roof steel structure are welded; fifthly, the supporting adjusting columns are cut in a segmented mode, and the cantilever steel structure is unloaded; sixthly, the mounting frame is hoisted to the position below the mounting position of the other section of the cantilever steel structure, the supporting adjusting columns are welded to the conversion platform again, and the second step to the fifth step are repeated; according to the method, the cantilever steel structure is installed in blocks, the construction occupied area is small, the hoisting safety risk and the cantilever steel structure deformation risk are reduced, and the installation elevation of the cantilever steel structure is met.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering construction, and in particular to an installation method for a cantilever steel structure on a high-altitude roof. Background Art

[0002] During the construction process, for the installation method of a cantilever steel structure on a high-altitude roof, usually two lifting machines are used for lifting or a large machine is used to hoist it at one time to an installation position at least 20 m above the ground to weld and connect the cantilever steel structure with the roof steel structure. However, in the on-site construction environment, if the size of the cantilever steel structure is too large, for example, in the construction of a house, the length of the cantilever steel structure involved is 10.4 m, the structural length is 45 m, the height is 25 m, and the total weight is 95 tons. If the above method is used, two lifting machines are used for lifting or a large machine is used to hoist it in place at one time, the required site for the lifting machine and the like is large. When the site is narrow, it is impossible to meet the entry of the lifting machine and the like. Moreover, when the long cantilever steel structure is hoisted integrally, due to its large weight and length, its hoisting height is high, the safety risk is large, and the cantilever steel structure is prone to deformation due to uneven stress during the hoisting process; if it is installed by block hoisting, it is impossible to ensure whether it is flat after welding and to meet the installation elevation of the cantilever steel structure. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an installation method for a cantilever steel structure on a high-altitude roof, which is mainly used for the installation of a cantilever steel structure on a high-altitude roof, so as to achieve the purpose of installing the cantilever steel structure in blocks, with a small construction floor area, reducing the hoisting safety risk and the deformation risk of the cantilever steel structure, and at the same time meeting the installation elevation of the cantilever steel structure.

[0004] An installation method for a cantilever steel structure on a high-altitude roof disclosed by the present invention includes:

[0005] Step 1: Install an installation frame for supporting the cantilever steel structure below the installation position of the cantilever steel structure;

[0006] The installation frame includes at least two parallel support racks for placing the cantilever steel structure. The support rack includes at least two rack units connected in sequence from top to bottom. A bolt for connecting the rack units is provided between adjacent two rack units; a conversion platform is provided at the top of the support rack, and a support adjustment column for supporting the cantilever steel structure is vertically provided on the conversion platform. The support adjustment columns are arranged around the conversion platform, and the length of the support adjustment column is greater than 0.8 m and less than 1 m; the bottom of the support rack is provided with a roadbed box arranged on the ground;

[0007] Step 2: Hoist the cantilever steel structure in segments onto the installation frame;

[0008] One side of the cantilever steel structure is connected to the roof steel structure, and the other side is placed on the support adjusting column;

[0009] Step 3: Cut the support adjusting column to adjust the height of the cantilever steel structure;

[0010] Cut the support adjusting column according to the height of the side where the cantilever steel structure is connected to the roof steel structure, so that the cantilever steel structure is horizontally placed on the support adjusting column;

[0011] Step 4: Weld the cantilever steel structure and the roof steel structure;

[0012] Step 5: Cut the support adjusting column in segments to unload the cantilever steel structure;

[0013] Mark the segmental cutting lines on the support adjusting column, and cut the support adjusting column from top to bottom along the segmental cutting lines. When the cutting reaches 30 mm, the unloading is completed;

[0014] Step 6: Hoist the installation frame to the position below the installation position of the other section of the cantilever steel structure, and weld the support adjusting columns around the conversion platform on the conversion platform again. Repeat Steps 2 to 5 to install the cantilever steel structure.

[0015] Further, Step 1 further includes arranging guy ropes around the support falsework. One end of each guy rope is connected to the top of the support falsework, and the other end is connected to a ground anchor arranged on the ground.

[0016] As a preferred method, the included angle between the guy rope and the ground is not greater than 45°.

[0017] Further, Step 1 further includes arranging a cage steel ladder along the height direction of the support falsework on the side of the support falsework.

[0018] Further, Step 5 includes:

[0019] The first cutting and unloading, the cutting amount of the support adjusting column is 5 - 8 mm. Observe the horizontal displacement of the support falsework, and add a vertically arranged temporary support between the support falsework and the cantilever steel structure; the second cutting and unloading, the cumulative cutting of the support adjusting column is 12 mm; the third cutting and unloading, the cumulative cutting of the support adjusting column is 20 mm; the fourth cutting and unloading, the cumulative cutting of the support adjusting column is 30 mm.

[0020] As a preferred method, after the first cutting and unloading, the second cutting and unloading, and the third cutting and unloading are completed, check the elevation and deformation of the cantilever steel structure; if the inspection result is normal, proceed to the next unloading; if the inspection result is abnormal, check the welds and hoist and reinforce the next group of cantilever steel structures to be installed.

[0021] Furthermore, the tire frame unit includes four vertically arranged columns, an upper support is welded between the tops of two adjacent columns, a lower support is welded between the bottoms of two adjacent columns, the columns, upper supports and lower supports are combined to form a frame structure, and a web cross brace is welded between two adjacent columns; connecting plates are welded at both ends of the columns, and first through holes for bolts to pass through are opened around the connecting plates.

[0022] As a preferred embodiment, an intermediate support connecting plate is provided at the intersection of the web cross brace, an upper stiffening plate is provided between the column and the upper support, and a lower stiffening plate is provided between the column and the lower support.

[0023] As a preferred embodiment, the roadbed box includes a steel beam bottom plate arranged on the ground, the steel beam bottom plate includes transverse supporting steel sections and longitudinal supporting steel sections arranged in a criss-cross pattern, and the steel beam bottom plate is also provided with four bottom plate connecting plates corresponding to the connecting plates arranged at the bottom of the columns, the bottom plate connecting plate is provided with a second through hole corresponding to the first through hole, and the first through hole is provided with connecting bolts that sequentially penetrate the first through hole and the second through hole.

[0024] Furthermore, the conversion platform is a springboard fully spread on the supporting tire frame.

[0025] The beneficial effects of the present invention are as follows: the installation method of the high-altitude roof cantilever steel structure, by arranging a mounting frame below the installation position of the cantilever steel structure, hoisting the cantilever steel structure in sections for welding and installation, effectively reducing the risk factor of high-altitude hoisting of heavy objects, and the segmented hoisting method reduces the weight and overall length of the hoisted object, reduces the hoisting safety risk and the risk of component deformation quality, and ensures economic benefits; a support adjustment column is arranged on the top of the mounting frame, and the installation height of the cantilever steel structure is adjusted by cutting the support adjustment column, and the stability of the cantilever steel structure during the welding process is ensured, and the cantilever steel structure will not tilt; and the support adjustment column is cut in sections to achieve graded unloading of the cantilever steel structure, avoiding structural instability caused by one-time cutting, and ensuring that the height of the cantilever steel structure will not change when it is installed in sections, meeting the requirements of its installation elevation; furthermore, the mounting frame occupies a small area, solving the problem that a large site is required for multiple or one large crane station. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 : A schematic diagram of the structure when the cantilever steel structure of the present invention is hoisted onto the mounting frame;

[0027] Figure 2 : Structural diagram of the mounting frame;

[0028] Figure 3 : Structural diagram of roadbed box;

[0029] Figure 4 : Structural diagram of the connecting plate;

[0030] Reference numerals: 1 - cantilever steel structure; 2 - mounting frame; 21 - support falsework; 211 - falsework unit; 212 - column; 213 - upper support; 2131 - upper stiffening plate; 214 - lower support; 2141 - lower stiffening plate; 215 - web cross brace; 2151 - intermediate support connecting plate; 216 - connecting plate; 217 - first through hole; 218 - bolt; 22 - conversion platform; 23 - support adjusting column; 24 - roadbed box; 241 - steel beam bottom plate; 242 - transverse support section steel; 243 - longitudinal support section steel; 244 - bottom plate connecting plate; 245 - second through hole; 246 - connecting bolt; 3 - guy wire; 31 - ground anchor; 4 - protective cage steel ladder. Detailed implementation manners

[0031] The present invention will be further described below.

[0032] An installation method for a high-altitude roof cantilever steel structure disclosed by the present invention is mainly used for the installation of a high-altitude roof cantilever steel structure, and includes:

[0033] Step 1: Install a mounting frame 2 for supporting the cantilever steel structure 1 below the installation position of the cantilever steel structure 1; the mounting frame 2 includes at least two support falseworks 21 arranged in parallel for placing the cantilever steel structure 1, the support falsework 21 includes at least two falsework units 211 connected in sequence from top to bottom, and a bolt 218 for connecting the falsework units 211 is provided between two adjacent falsework units 211; a conversion platform 22 is provided at the top of the support falsework 21, and a support adjusting column 23 for supporting the cantilever steel structure 1 is vertically provided on the conversion platform 22, the support adjusting column 23 is arranged around the conversion platform 22, and the length of the support adjusting column 23 is greater than 0.8 m and less than 100 mm; a roadbed box 24 provided on the ground is provided at the bottom of the support falsework 21.

[0034] Install the mounting rack 2 for supporting the cantilever steel structure 1. Specifically, first lay the roadbed box 24 serving as the base of the support falsework 21 below the installation position of the cantilever steel structure 1. The roadbed box 24 is arranged on the concrete ground to provide support force for the support falsework 21. Then assemble the support falsework 21. Set the support falsework 21 on the roadbed box 24. The support falsework 21 includes at least two falsework units 211 connected in sequence from top to bottom. The height of each falsework unit 211 is 6m. Adjust the height of the support falsework 21 by adjusting the number of falsework units 211 to adapt to the installation of the cantilever steel structure 1 with different heights. Adjacent falsework units 211 are connected by bolts for subsequent disassembly and repeated use to reduce costs. A conversion platform 22 is provided at the top of the support falsework 21 for placing the cantilever steel structure 1 to be installed for welding installation. A support adjustment column 23 is welded on the conversion platform 22. The support adjustment column 23 serves as a temporary support adjustment section to support the cantilever steel structure 1 and is also used for unloading and cutting to facilitate step-by-step unloading. The support adjustment column 23 can be made of 80×5 carbon steel welded steel pipe with a length of 0.8m - 1.0m, which saves costs while ensuring its support strength and facilitating cutting by operators. After assembling the support falsework 21, connect the support falsework 21 and the roadbed box 24. The support falsework 21 and the roadbed box 24 can be connected by bolts or welding. For easy disassembly, bolt connection is preferably used as much as possible. The mounting rack 2 includes at least two support falseworks 21 arranged in parallel to ensure stable support for the cantilever steel structure 1. The number of support falseworks 21 is selected according to the length of the cantilever steel structure 1.

[0035] Step 2: Hoist the cantilever steel structure 1 in sections onto the mounting rack 2; the cantilever steel structure 1 is at least divided into two sections. One side of one section of the cantilever steel structure 1 is connected to the roof steel structure, and the other side is placed on the support adjustment column 23; the other cantilever steel structures 1 are welded and connected in sequence. The cantilever steel structure 1 is at least divided into two sections, and it is hoisted, welded and installed in sections to avoid the large floor area required by the hoisting machinery for overall hoisting of the cantilever steel structure 1 or the deformation of the cantilever steel structure 1 during the overall hoisting process, thus improving the hoisting safety.

[0036] Step 3: Cut the support adjustment column 23 and adjust the height of the cantilever steel structure 1; cut the support adjustment column 23 according to the height of the side of the cantilever steel structure 1 connected to the roof steel structure so that the cantilever steel structure 1 is horizontally placed on the support adjustment column 23; specifically, adjust the height of the cantilever steel structure 1 placed on the support adjustment column 23 so that the cantilever steel structure 1 is horizontally placed on the support adjustment column 23 to ensure the installation accuracy of the cantilever steel structure 1.

[0037] Step 4: Weld the cantilever steel structure 1 and the roof steel structure; weld and fix the cantilever steel structure 1 and the roof steel structure; ensure the horizontality of the cantilever steel structure 1 during the welding process and always keep it installed at the specified height position.

[0038] Step Five: Segmentally cut the support adjustment column 23 to unload the cantilever steel structure 1; Mark the segmental cutting lines on the support adjustment column 23, and sequentially cut the support adjustment column 23 from top to bottom along the segmental cutting lines. When the support adjustment column 23 is cumulatively cut by 30 mm, the unloading is completed; To avoid structural instability caused by one-time cutting, segmental cutting and unloading are adopted to achieve staged unloading. The unloading method adopts overall synchronous unloading, and the displacement is controlled by flame-cutting the support adjustment column 23 between the temporary support bracket 21 and the cantilever steel structure 1 to achieve smooth load transfer; According to the magnitude of the unloading amount, mark the segmental cutting lines on the support adjustment column 23 so that the operator can cut the support adjustment column 23 according to the segmental cutting lines, realizing gradual load release, reducing the stress release speed, and at the same time facilitating the inspection of the support adjustment column 23 and the cantilever steel structure 1 according to the situation of each cutting. Arrange the auxiliary support mechanism to ensure that it remains flat after welding and meets the installation elevation requirements of the cantilever steel structure 1. Repeatedly cut the support adjustment column 23 until the unloading is completed.

[0039] Step Six: Hoist the mounting frame 2 below the installation position of another section of the cantilever steel structure 1, and weld the support adjustment columns 23 around the conversion platform 22 on the conversion platform 22 again, and repeat Steps Two to Five to install the cantilever steel structure 1; Hoist the mounting frame 2 below the installation position of another section of the cantilever steel structure 1 to realize turnover use, and re-weld new support adjustment columns 23 on the conversion platform 22 to support the welded installation of the cantilever steel structure 1.

[0040] The installation method of the high-altitude roof cantilever steel structure effectively reduces the risk coefficient of hoisting heavy objects at high altitude by setting the mounting frame 2 below the installation position of the cantilever steel structure 1 and segmentally hoisting and welding the cantilever steel structure 1. The segmental hoisting method reduces the weight and overall length of the hoisted object, reducing the hoisting safety risk and the component deformation quality risk, and ensuring economic benefits; The support adjustment column 23 is arranged at the top of the mounting frame 2, and the installation height of the cantilever steel structure 1 is adjusted by cutting the support adjustment column 23, and the stability of the cantilever steel structure 1 during the welding process is ensured, and it will not tilt; Moreover, the staged unloading of the cantilever steel structure 1 is realized by segmentally cutting the support adjustment column 23, avoiding structural instability caused by one-time cutting, and ensuring that the height of the cantilever steel structure 1 will not change during segmental installation, meeting the requirements of its installation elevation; Furthermore, the mounting frame 2 occupies a small area, solving the problem that a large number of or one large crane requires a large site for positioning.

[0041] Furthermore, to ensure the stability of the support scaffold 21, as shown in the figure, the first step further includes arranging guy ropes 3 around the support scaffold 21. One end of each guy rope 3 is connected to the top of the support scaffold 21, and the other end is connected to a ground anchor 31 set on the ground. By setting the guy ropes 3 and the ground anchors 31 as anti-overturning measures for the support scaffold 21, the overall stability of the support scaffold 21 is improved. As a preferred method, the angle between the guy rope 3 and the ground is not greater than 45°, to avoid an excessive increase in the required layout space due to too large an angle between the guy rope 3 and the ground. The above-mentioned ground anchor 31 is driven into the soil to a depth of 2 m.

[0042] To facilitate the operation personnel to climb along the support scaffold 21 to the conversion platform 22 for construction operations, the first step further includes providing a cage steel ladder 4 on the side of the support scaffold 21 and arranged along the height direction of the support scaffold 21. By providing the cage steel ladder 4, it is convenient for the operation personnel to climb, and at the same time, it can ensure the operation safety and improve the safety.

[0043] After multiple tests, when segmentally cutting the support adjusting column 23 and unloading the cantilever steel structure 1, it is found that it is best to divide it into four cuts. Specifically, the fifth step includes: the first cut and unloading, the cutting amount of the support adjusting column 23 is 5 - 8 mm; the second cut and unloading, the cumulative cutting of the support adjusting column 23 is 12 mm; the third cut and unloading, the cumulative cutting of the support adjusting column 23 is 20 mm; the fourth cut and unloading, the cumulative cutting of the support adjusting column 23 is 30 mm. To ensure that the height of the already installed cantilever steel structure 1 does not change after each cut and unloading, to ensure the flatness after the welded connection of the cantilever steel structure 1, and to meet the installation elevation of the cantilever steel structure 1; it is necessary to check the installation of the cantilever steel structure 1 after each cut and unloading. Specifically, after the first cut and unloading is completed, observe the horizontal displacement of the support scaffold 21, and check the welding and deformation of the main joints and main stressed members of the structure. If there is no abnormal situation, proceed to the second cut and unloading; if there is an abnormality, add a vertically arranged temporary support between the support scaffold 21 and the cantilever steel structure 1; this temporary support can be supported by a short pipe. After the second cut and unloading and the third cut and unloading are completed, check the elevation and deformation of the cantilever steel structure 1; if there is no abnormality, proceed to the next unloading; if there is an abnormality, check the welds and hoist and reinforce the next section of the cantilever steel structure 1 to be installed. By segmentally cutting and unloading, it is possible to avoid structural mutations caused by the release of instantaneous loads; after the first cut, add a temporary support to enhance safety; when deformation is detected during continuous cutting and unloading, immediately reinforce the welds and hoist and reinforce the next section of the cantilever steel structure 1 to be installed to prevent the height of the cantilever steel structure 1 from changing during segmented installation and not meeting the installation elevation requirements.

[0044] Specifically, as shown in the figure, the support jig unit 211 in the above-mentioned support jig 21 includes four vertically arranged columns 212. An upper support 213 is welded between the tops of two adjacent columns 212, and a lower support 214 is welded between the bottoms of two adjacent columns 212. The columns 212, the upper support 213, and the lower support 214 enclose a frame structure, and a web cross brace 215 is welded between two adjacent columns 212. Connecting plates 216 are welded to both ends of the column 212, and first through holes 217 for bolts 218 to pass through are provided around the connecting plates 216. By enclosing a frame structure with the columns 212, the upper support 213, and the lower support 214, and arranging the web cross brace 215 to ensure the stability of the frame structure after placing the cantilever steel structure 1, connecting plates 216 are welded to both ends of the column 212, and first through holes 217 are provided in the connecting plates 216. When connecting the support jig units 211 from top to bottom, align the connecting plates 216 of the upper support jig unit 211 with the connecting plates 216 of the lower support jig unit 211, and pass the bolts 218 through the first through holes 217 to connect the upper and lower support jig units 211. These bolts 218 also use high-strength bolts to ensure the connection stability.

[0045] To ensure the stability of each support jig unit 211 after placing the to-be-installed cantilever steel structure 1, as shown in the figure, an intermediate support connecting plate 2151 is provided at the intersection of the web cross brace 215, a top stiffening plate 2131 is provided between the column 212 and the upper support 213, and a bottom stiffening plate 2141 is provided between the column 212 and the lower support 214. The web cross brace 215 is an anti-lateral force member, and stress distortion is likely to occur at the intersection due to shear force concentration, which may cause the web cross brace 215 to deform. An intermediate support connecting plate 2151 is provided at the intersection of the web cross brace 215 to strengthen the strength of the connection node at the intersection of the web cross brace 215, so that no deformation will occur during use. A top stiffening plate 2131 is provided between the column 212 and the upper support 213, and a bottom stiffening plate 2141 is provided between the column 212 and the lower support 214 to enhance the strength of the connection nodes between the column 212 and the upper support 213 and the lower support 214, and ensure that the support jig unit 211 will not deform during use, resulting in the instability of the support jig 21.

[0046] As a preferred method, to ensure the connection stability between the roadbed box 24 and the support bracket 21, as shown in the figure, the roadbed box 24 includes a steel beam bottom plate 241 disposed on the ground. The steel beam bottom plate 241 includes a transverse support section steel 242 and a longitudinal support section steel 243 arranged in a grid pattern. Four bottom plate connection plates 244 corresponding to the connection plates 216 provided at the bottom of the columns 212 are further provided on the steel beam bottom plate 241. A second through hole 245 corresponding to the first through hole 217 is formed on the bottom plate connection plate 244. A connection bolt 246 is provided on the first through hole 217 and sequentially penetrates through the first through hole 217 and the second through hole 245. The steel beam bottom plate 241 arranged in a grid pattern increases the contact area between the bottom of the support bracket 21 and the ground, avoiding ground settlement. To facilitate the disassembly of the entire installation frame 2 after the cantilever steel structure 1 is completed, four bottom plate connection plates 244 are provided on the steel beam bottom plate 241. The bottom plate connection plates 244 are arranged in one-to-one correspondence with the connection plates provided at the bottom of the columns 212. A second through hole 245 corresponding to the first through hole 217 is formed on the bottom plate connection plate 244. The connection bolt 246 is used to connect the bracket unit 211 at the bottom of the support bracket 21 to the bottom plate connection plate 244. The above connection bolt 246 is a high-strength bolt, ensuring the connection strength and connection stability.

[0047] To save costs, as shown in the figure, the conversion platform 22 is a jump board fully laid on the support bracket 21; using the common jump boards at the construction site to fully lay on the support bracket 21 can utilize local materials, reducing the construction cost.

Claims

1. A method for installing a high-altitude roof cantilever steel structure, characterized in that: include: Step 1: Installing a mounting frame (2) for supporting the cantilever steel structure (1) below the mounting position of the cantilever steel structure (1); The mounting frame (2) comprises at least two support frames (21) arranged in parallel for placing the cantilever steel structure (1), the support frame (21) comprising at least two frame units (211) connected in sequence from top to bottom, and bolts (218) for connecting the frame units (211) are arranged between two adjacent frame units (211); a conversion platform (22) is arranged on the top of the support frame (21), and a support adjustment column (23) for supporting the cantilever steel structure (1) is vertically arranged on the conversion platform (22), and the support adjustment column (23) is arranged around the conversion platform (22), and the length of the support adjustment column (23) is greater than 0.8m and less than 100mm; a roadbed box (24) arranged on the ground is arranged at the bottom of the support frame (21); Step 2: hoisting the cantilever steel structure (1) onto the mounting frame (2) in sections; The cantilever steel structure (1) is divided into at least two sections, one side of which is connected to the roof steel structure, and the other side is placed on the support adjustment column (23); Step 3: cutting the support adjustment column (23) to adjust the height of the cantilever steel structure (1); The support adjustment column (23) is cut according to the height of the side where the cantilever steel structure (1) is connected to the roof steel structure, so that the cantilever steel structure (1) is placed horizontally on the support adjustment column (23); Step 4: Welding the cantilever steel structure (1) to the roof steel structure; Step 5: Cut the support adjustment column (23) in sections to unload the cantilever steel structure (1); Mark the segmented cutting lines on the support adjustment column (23), and cut the support adjustment column (23) from top to bottom along the segmented cutting lines. When the cutting reaches 30 mm, the unloading is completed; Step 6: hoist the mounting frame (2) to the lower part of the mounting position of another cantilever steel structure (1), weld the support adjustment columns (23) around the conversion platform (22) on the conversion platform (22) again, and repeat steps 2 to 5 to install the cantilever steel structure (1).

2. The installation method for a high-altitude roof cantilever steel structure according to claim 1, characterized in that: The step one also includes laying a guy rope (3) around the supporting frame (21), wherein one end of the guy rope (3) is connected to the top of the supporting frame (21), and the other end is connected to a ground anchor (31) arranged on the ground.

3. A method for installing a high-altitude roof cantilever steel structure as claimed in claim 2, characterized in that: The angle between the guy rope (3) and the ground is no greater than 45°.

4. The installation method for a high-altitude roof cantilever steel structure according to claim 1, characterized in that: The step one also includes providing a cage steel ladder (4) on the side of the supporting tire frame (21) and arranged along the height direction of the supporting tire frame (21).

5. The installation method for a high-altitude roof cantilever steel structure according to claim 1, characterized in that: The step five comprises: The first cutting and unloading has a cutting amount of 5-8 mm for the support adjustment column (23); the second cutting and unloading has a cumulative cutting amount of 12 mm for the support adjustment column (23); the third cutting and unloading has a cumulative cutting amount of 20 mm for the support adjustment column (23); and the fourth cutting and unloading has a cumulative cutting amount of 30 mm for the support adjustment column (23).

6. A method for installing a high-altitude roof cantilever steel structure as claimed in claim 5, characterized in that: After the first cutting and unloading is completed, the horizontal displacement of the support frame (21) is observed, and the welding and deformation of the main nodes and main load-bearing components of the structure are checked. If there is no abnormality, a second cutting and unloading is performed; if there is an abnormality, a temporary support is added vertically between the support frame (21) and the cantilever steel structure (1); after the second cutting and unloading and the third cutting and unloading are completed, the elevation and deformation of the cantilever steel structure (1) are checked; If there is no abnormality, proceed to the next uninstallation; If there is any abnormality, the welds are checked and the next set of cantilever steel structures (1) to be installed are hoisted and reinforced.

7. The installation method for a high-altitude roof cantilever steel structure according to claim 1, characterized in that: The tire frame unit (211) includes four vertically arranged columns (212), an upper support (213) is welded between the tops of two adjacent columns (212), and a lower support (214) is welded between the bottoms of two adjacent columns (212). The columns (212), the upper support (213), and the lower support (214) are enclosed to form a frame structure, and a web cross brace (215) is welded between two adjacent columns (212); connecting plates (216) are welded at both ends of the columns (212), and first through holes (217) for bolts (218) to pass through are opened around the connecting plates (216).

8. The method for installing a high-altitude roof cantilever steel structure according to claim 7, characterized in that: An intermediate support connecting plate (2151) is provided at the intersection of the web cross brace (215), an upper stiffening plate (2131) is provided between the column (212) and the upper support (213), and a lower stiffening plate (2141) is provided between the column (212) and the lower support (214).

9. The method for installing a high-altitude roof cantilever steel structure according to claim 7, characterized in that: The roadbed box (24) includes a steel beam bottom plate (241) arranged on the ground, the steel beam bottom plate (241) includes a transverse support steel (242) and a longitudinal support steel (243) arranged in a tic-tac-toe pattern, the steel beam bottom plate (241) is also provided with four bottom plate connecting plates (244) corresponding to the connecting plates (216) arranged at the bottom of the column (212), the bottom plate connecting plate (244) is provided with a second through hole (245) corresponding to the first through hole (217), and the first through hole (217) is provided with a connecting bolt (246) that passes through the first through hole (217) and the second through hole (245) in sequence.

10. The installation method for a high-altitude roof cantilever steel structure according to claim 1, characterized in that: The conversion platform (22) is a springboard fully spread on the supporting tire frame (21).

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