Welding method of variable cross-section steel structure Y-shaped column of large-span roof

Abstract

The application belongs to the technical field of terminal building, and relates to a variable cross-section steel structure Y-shaped column welding method for a large-span roof. The variable cross-section steel structure Y-shaped column is welded in sections. During welding, the welding method of first outside and then inside and first upper section and then lower end is adopted. Meanwhile, after each section of the drain pipe is welded, the section of the drain pipe is fixed to prevent the gravity of the drain pipe from accumulating at the drain pipe at the bottom layer and thus affecting the welding quality of the drain pipe. The problem that the variable cross-section steel structure Y-shaped column for supporting the large-span roof of a large airport terminal building cannot be welded is solved. The problem that the accumulation of welding stress and the gravity of the drain pipe greatly affects the welding quality and service life of the drain pipe and the variable cross-section steel structure Y-shaped column is also solved.

Description

Technical Field

[0001] This invention belongs to the field of terminal building technology and relates to a welding method for Y-shaped steel columns with variable cross-sections in large-span roofs. Background Technology

[0002] Airport terminals, as a crucial component of airports, play a vital role in the operation of the airport and the passengers traveling to and from it. Large airport terminals often feature roofs with uneven, non-horizontal steel structures. Therefore, variable cross-section steel Y-shaped columns are used to support the large-span steel roof. Due to the large area of ​​the roof, drainage systems are crucial during rain and snow. Furthermore, the large roof area necessitates drainage not only at the edges but also in the central area. The drainage pipes must descend simultaneously with the variable cross-section steel Y-shaped columns. Considering the supporting columns within the airport terminal, the only viable drainage method is to install drainage pipes within the variable cross-section steel Y-shaped columns.

[0003] However, due to the large overall size of the variable cross-section steel Y-shaped column, it can only be welded on-site by hoisting. When welding the internal drainage pipes first and then the external steel structure on-site, the already welded internal drainage pipes will be damaged and stress will accumulate during the welding of the external steel structure. On the other hand, if the external steel structure is welded first and then the internal drainage pipes are welded, the internal welding will be impossible after the external welding is completed. In addition, the accumulation of welding stress and the weight of the drainage pipes will have a significant impact on the welding quality and service life of the drainage pipes and the variable cross-section steel Y-shaped column.

[0004] Therefore, a welding method for Y-shaped columns of steel structures with cross-sections capable of supporting large-span steel structures is needed to solve the above problems. Summary of the Invention

[0005] The technical solution adopted by this invention to solve the technical problem is: a welding method for Y-shaped columns of variable cross-section steel structures in large-span roofs, comprising the following steps:

[0006] Step 1: Weld the main branch, connecting section, and branch sections of the variable cross-section steel Y-shaped column according to the design requirements. The main branch is a vertical column section, the connecting section is an inverted "eight"-shaped curved section, and the branch sections are upward-branching inclined support column sections. Drainage pipes with movable connections are reserved in the main branch, connecting section, and branch sections. Welding windows connecting the inside and outside of the pipe wall are reserved at the joints at both ends of the main branch and branch sections. It is possible to choose to weld and process the sections in the factory and then transport them to the site for welding and installation, or to weld the sections on site and then install them directly.

[0007] Step 2: Hoist and install the main branch section, welding the bottom of the main branch section's steel profile to the pre-embedded base in the ground concrete; hoist and install the connecting section, welding the bottom of the connecting section's curved section to the top of the main branch section's steel profile; hoist and install the connecting section's branch section, welding the bottom of the branch section's steel profile to the top of the connecting section's curved section; by welding the outer walls of each pipe section first and then welding the drainage pipes inside the pipe section, damage, destruction, and stress accumulation caused to the welded drainage pipes when welding the drainage pipes first and then welding the outer walls of each pipe section can be effectively prevented.

[0008] Step 3: Weld the lower end of the drainage pipe in the branch section to the upper end of the drainage pipe in the connecting section through the welding window at the bottom of the branch section. After welding is completed, fix the drainage pipe in the branch section radially to the inner wall of the branch section.

[0009] Step 4: Weld the lower end of the drainage pipe in the connecting section to the upper end of the drainage pipe in the main branch section through the welding window at the top of the main branch section. After welding is completed, fix the drainage pipe in the connecting section radially to the inner wall of the connecting section.

[0010] Step 5: Weld the lower end of the drainage pipe in the main branch section to the drainage interface of the drainage pipe in the pre-embedded base in the ground concrete through the welding window at the bottom of the main branch section. After welding, fix the drainage pipe in the main branch section radially to the inner wall of the main branch section. Weld the drainage pipe from top to bottom, and fix each section to the inner wall of each section after welding before continuing to weld the next section. This ensures that most of the weight of each section of drainage pipe after welding is borne by the inner wall of the steel structure of its own section. This avoids the situation where the weight of the drainage pipe increases step by step from top to bottom when welding from bottom to top, which would eventually cause the bottom drainage pipe to bear a large weight load at the welding point and the fixed connection point, thus affecting the welding quality and service life of the lower drainage pipe.

[0011] Step Six: Weld the upper opening of the drainage pipe in the branch section to the downhole of the roof drainage gutter through the welding window at the top joint of the branch section; welding the downhole at the top of the drainage pipe last can prevent the drainage pipe from falling due to its own weight and pulling on the top weld if it is welded first, thereby affecting the quality, airtightness and watertightness of the top weld.

[0012] Step 7: Conduct airtightness and watertightness checks on the drainage pipes inside the Y-shaped column of the variable cross-section steel structure, and carry out anti-condensation construction.

[0013] Step 8: Seal the windows of each welded window by welding the steel structure plate; the welded windows are used to solve the problem that the outer wall of the steel structure cannot be welded inside after the outer wall is closed when welding is done from the outside to the inside. Therefore, after welding and fixing the internal drainage pipes, the welded windows are sealed.

[0014] Step 9: System test, overall water tightness check, and after the test is passed, carry out anti-condensation construction on each exposed part.

[0015] Preferably, in step one, a main branch partition with a cross-section of "+" is fixedly installed in the main branch section, and four drainage pipes are evenly distributed in the main branch section. A branch partition with a cross-section of "I" is installed in the branch section, and two drainage pipes are evenly distributed in the branch section. After passing through the connecting section, the four drainage pipes in the main branch section fork on both sides and distribute two drainage pipes to each of the two branch sections. The partition can effectively enhance the vertical and horizontal strength of the steel profile, and the partition inside the steel profile structure can place each drainage pipe in different up and down channels separated by the partition, which facilitates the separate fixing of the drainage pipes in each channel.

[0016] More preferably, in step one, multiple adjustable pipe clamps with adjustable circumference sizes are fixedly installed on the inner walls of the main branch section, the connecting section, the branch section, the main branch partition, and the branch partition. When the drain pipe passes through the inner cavity of the main branch section, the connecting section, and the branch section, the adjustable pipe clamps are respectively fitted onto the outer circumference of the drain pipe. In steps three, four, and five, after the drain pipe is welded and fixed radially to the inner wall of each section, the adjustable pipe clamps are used to tighten the connection. The adjustable pipe clamps facilitate the fixed connection after the welded drain pipe sections are completed, effectively distributing the weight of each drain pipe section evenly to the inner wall of the steel structure or the side wall of the partition where each drain pipe section is located. This alleviates the problem of the gravity increasing as the weight accumulates to lower layers.

[0017] More preferably, in step one, radially extending partition welding holes are provided on the main branch partition and the branch partition, and the opening position of the partition welding holes matches the welding window; the welding window can be opened on both opposite sides as needed or symmetrically opened on all four sides according to the position of the drainage pipe. The partition welding holes are used to solve the problem that the drainage pipe on the side away from the welding window cannot be welded due to insufficient space in the inner wall of the steel structure because the welding window can only be aligned with one side of the drainage pipe. During welding, the welding tool can be inserted through the partition welding hole from the opposite welding window to weld the inner circumference of the drainage pipe. After the inner weld is completed, the welding tool can be rotated back to the welding window on the side where the drainage pipe is located to weld the outer circumference of the drainage pipe, thereby solving the problem that the drainage pipe cannot be rotated and welded in a small space.

[0018] More preferably, the partition plate around the weld hole is provided with reinforcing ribs; since the partition plate bears a large vertical weight, reinforcing ribs or reinforcing ribs are added at the location where the weld hole is opened to compensate for the strength loss caused by the weld hole.

[0019] Preferably, in step one, both ends of the main branch section and the branch section are provided with end caps. The end caps seal both ends of the main branch section and the branch section pipe segment. The end caps are set perpendicular to the length direction of the drainage pipe and have circular cover holes for the drainage pipe to pass through. The end caps can support the outer wall and partition of the steel structure, effectively enhancing the vertical and horizontal strength of the steel structure. The reserved cover holes allow the drainage pipe to pass through smoothly, thus ensuring the strength of the steel structure and meeting the requirements for the drainage pipe to pass through.

[0020] More preferably, in step one, the two ends of the drainage pipe in the connecting section extend out of the upper and lower ends of the steel structure of the connecting section, respectively. During welding, the upper end of the drainage pipe in the connecting section extends into the branch section, and the lower end of the drainage pipe in the connecting section extends into the main branch section. The drainage pipe in the connecting section extends into both ends of the main branch section and the branch section, which facilitates the welding operator to perform welding operations on the joint of the drainage pipe through the welding window.

[0021] Preferably, in step one, an airtightness check is performed before each section of the drainage pipe is placed into the main branch, connecting section, and branch section. In steps three, four, and five, a watertightness check is performed after each splicing and welding is completed. Only after the check is confirmed to be qualified can the next welding step or the next process be carried out. After each section is welded, the welding performance and pipeline are checked to prevent the repetition and waste of time, manpower, and material resources caused by discovering problems in the previous process after the next process is completed.

[0022] Preferably, in step two, the main branch segment is a variable cross-section column with radial dimensions gradually increasing from bottom to top, and each segment of the main branch segment is welded in sections; in step five, the drainage pipes in each main branch segment are welded together in a top-down order; when the main branch segment is long, the main branch segment is also welded by first welding the outside and then the inside, and first welding the upper section and then the lower section, to reduce the downward accumulation of gravity and avoid damage to the drainage pipe; when the connecting section is long, the segmented welding connection can also be adopted by welding from top to bottom and from the outside to the inside.

[0023] Preferably, in step six, a metal corrugated pipe is provided at the weld between the upper opening of the drainage pipe in the branch section and the roof drainage gutter outlet; the metal corrugated pipe can effectively prevent displacement caused by thermal expansion and contraction and other reasons from affecting the displacement of the roof outlet and the upper opening of the drainage pipe at the top of the Y-shaped column.

[0024] The beneficial effects of this invention are:

[0025] This invention solves the problem of welding variable cross-section steel Y-shaped columns in large airport terminal buildings with external sections first, then internal sections, and upper sections first, then lower sections. Furthermore, each section of the drainage pipe is fixed after welding to prevent the weight of the drainage pipe from accumulating at the bottom and affecting the welding quality. This addresses the issue of welding variable cross-section steel Y-shaped columns for large-span roof supports in large airport terminals, and also resolves the problem that welding stress and the accumulation of drainage pipe weight significantly impact the welding quality and service life of both the drainage pipe and the variable cross-section steel Y-shaped column. Attached Figure Description

[0026] Figure 1 This is an exploded welding diagram of a welding method for Y-shaped columns of variable cross-section steel structures with a large-span roof.

[0027] Figure 2 This is a schematic diagram of the completed welding process;

[0028] Figure 3 This is a schematic diagram of the welded window cross-section;

[0029] Figure 4 This is a schematic diagram of the welding of the main branch segment;

[0030] Figure 5 This is a schematic diagram of the branch segment welding;

[0031] Figure 6 This is a schematic diagram of the welding process after the drain pipe is installed.

[0032] In the diagram: 1. Main branch segment; 2. Connecting segment; 3. Branch segment; 4. Drainage pipe; 5. Welded window; 6. Main branch partition; 7. Branch partition; 8. Adjustable pipe clamp; 9. Partition weld hole; 10. Reinforcing rib; 11. End cap; 12. Cover hole. Detailed Implementation

[0033] The related technologies of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0034] refer to Figures 1-6 A welding method for Y-shaped columns of variable cross-section steel structures with large-span roofs includes the following steps:

[0035] Step 1: Weld the main branch segment 1, connecting segment 2, and branch segment 3 of the variable cross-section steel Y-shaped column according to the design requirements. The main branch segment 1 is a vertical column segment, the connecting segment 2 is an inverted "eight"-shaped curved segment, and the branch segment 3 is an upward-branching inclined support column segment. Drainage pipes 4 with movable connections are reserved in the main branch segment 1, connecting segment 2, and branch segment 3. Welding windows 5 connecting the inside and outside of the pipe wall are reserved at the joints at both ends of the main branch segment 1 and branch segment 3. It is possible to choose to weld and process the segments in the factory and then transport them to the site for welding and installation, or to weld the segments on site and then install them directly.

[0036] Step 2: Hoist and install the main branch section 1, welding the bottom of the steel section 1 to the pre-embedded base in the ground concrete; hoist and install the connecting section 2, welding the bottom of the curved section of the connecting section 2 to the top of the steel section of the main branch section 1; hoist and install the branch section 3 of the connecting section, welding the bottom of the steel section of the branch section 3 to the top of the curved section of the connecting section 2; by welding the outer wall of each pipe section first and then welding the drainage pipe 4 inside the pipe section, damage, destruction and stress accumulation caused to the welded drainage pipe 4 when welding the drainage pipe 4 first and then welding the outer wall of each pipe section can be effectively prevented.

[0037] Step 3: Weld the lower end of the drainage pipe 4 in the branch section 3 to the upper end of the drainage pipe 4 in the connecting section 2 through the welding window 5 at the bottom of the branch section 3. After the welding is completed, fix the drainage pipe 4 in the branch section 3 radially to the inner wall of the branch section 3.

[0038] Step 4: Weld the lower end of the drainage pipe 4 in the connecting section 2 to the upper end of the drainage pipe 4 in the main branch section 1 through the welding window 5 at the top of the main branch section 1. After the welding is completed, fix the drainage pipe 4 in the connecting section 2 radially to the inner wall of the connecting section 2.

[0039] Step 5: Weld the lower end of the drainage pipe 4 in the main branch section 1 to the drainage interface of the drainage pipe 4 in the pre-embedded base in the ground concrete through the welding window 5 at the bottom of the main branch section 1. After welding, fix the drainage pipe 4 in the main branch section 1 radially to the inner wall of the main branch section 1. Weld the drainage pipe 4 from top to bottom, and fix each section to the inner wall of each section after welding before continuing to weld the next section of drainage pipe 4. This ensures that most of the weight of each section of drainage pipe 4 after welding is borne by the inner wall of the steel structure of its own section. This avoids the situation where the weight of the drainage pipe 4 increases from top to bottom when welding from bottom to top, which would eventually lead to a large weight load on the bottom drainage pipe 4 welding point and fixed connection point, thus affecting the welding quality and service life of the lower drainage pipe 4.

[0040] Step 6: Weld the upper opening of the drainage pipe 4 inside the branch section 3 to the drain outlet of the roof drainage gutter through the welding window 5 at the top joint of the branch section 3; Finally, welding the drain outlet at the top of the drainage pipe 4 can prevent the drainage pipe 4 from falling due to its own weight and pulling on the top weld if it is welded first, thereby affecting the quality, airtightness and watertightness of the top weld.

[0041] Step 7: Conduct airtightness and watertightness checks on the drainage pipes inside the Y-shaped column of the variable cross-section steel structure, and carry out anti-condensation construction.

[0042] Step 8: Seal the windows of each welded window 5 by welding the steel structure plate; the welded window 5 is used to solve the problem that the outer wall of the steel structure cannot be welded inside after the outer wall is closed when welding is done from the outside to the inside. Therefore, after welding and fixing the internal drainage pipe 4 at each part, the welded window is sealed.

[0043] Step 9: System test, overall water tightness check, and after the test is passed, carry out anti-condensation construction on each exposed part.

[0044] Furthermore, in step one, a main branch partition 6 with a cross-section of "+" is fixedly installed in the main branch segment 1, and four drainage pipes 4 are evenly distributed in the main branch segment 1. A branch partition 7 with a cross-section of "I" is installed in the branch segment 3, and two drainage pipes 4 are evenly distributed in the branch segment 3. After passing through the connecting segment 2, the four drainage pipes 4 in the main branch segment 1 branch on both sides and distribute two drainage pipes 4 to each of the two branch segments 3. The partition can effectively enhance the vertical and horizontal strength of the steel profile, and the partition inside the steel profile structure can place each drainage pipe 4 in different up and down channels separated by the partition, which facilitates the separate fixing of the drainage pipes 4 in each channel.

[0045] Furthermore, in step one, multiple adjustable pipe clamps 8 with adjustable circumference are fixedly installed on the inner walls of the main branch segment 1, the connecting segment 2, the branch segment 3, the main branch partition 6, and the branch partition 7. When the drain pipe 4 passes through the inner cavity of the main branch segment 1, the connecting segment 2, and the branch segment 3, the adjustable pipe clamps 8 are respectively fitted onto the outer circumference of the drain pipe 4. In steps three, four, and five, after the drain pipe 4 is welded and fixed radially to the inner wall of each segment, it is connected by shrinking and clamping the adjustable pipe clamps 8. The adjustable pipe clamps 8 facilitate the fixed connection after the welding of each segment of the drain pipe 8, effectively distributing the weight of each segment of the drain pipe 4 evenly to the inner wall of the steel structure or the side wall of the partition where each segment of the drain pipe 4 is located; alleviating the problem of the gravity increasing as it goes down due to the accumulation of gravity.

[0046] Furthermore, in step one, radially extending partition welding holes 9 are provided on the main branch partition 6 and the branch partition 7. The opening position of the partition welding holes 9 matches the welding window 5. The welding window 5 can be opened on both opposite sides as needed or symmetrically opened on all four sides according to the position of the drain pipe 4. The partition welding holes 9 are used to solve the problem that the drain pipe 4 on the side away from the welding window 5 cannot be welded due to insufficient space in the inner wall of the steel structure because the welding window 5 can only be aligned with one side of the drain pipe 4. During welding, the welding tool can be inserted through the partition welding hole 9 from the opposite side welding window 5 to weld the inner circumference of the drain pipe 4. After the inner weld is completed, it can be rotated back to the welding window 5 on the side where the drain pipe 4 is located to weld the outer circumference of the drain pipe 4, thereby solving the problem that the drain pipe 4 cannot be rotated and welded in a small space.

[0047] Furthermore, the partition plate around the weld hole 9 is provided with reinforcing ribs 10; because the partition plate bears a large vertical gravity, reinforcing ribs 10 or reinforcing ribs are added at the location where the weld hole 9 is opened to compensate for the strength loss caused by the weld hole 9.

[0048] Furthermore, in step one, both ends of the main branch segment 1 and the branch segment 3 are respectively provided with end caps 11. The end caps 11 seal both ends of the main branch segment 1 and the branch segment 3. The end caps 11 are set perpendicular to the length direction of the drainage pipe 4. The end caps 11 are provided with circular cover holes 12 for the drainage pipe 4 to pass through. The end caps 11 can support the outer wall and partition of the steel structure, effectively enhancing the vertical and horizontal strength of the steel structure. The reserved cover holes 12 allow the drainage pipe 4 to pass through smoothly, thus ensuring the strength of the steel structure and allowing the drainage pipe 4 to pass through.

[0049] Furthermore, in step one, the two ends of the drain pipe 4 inside the connecting section 2 extend out of the upper and lower ends of the steel structure of the connecting section 2, respectively. During welding, the upper end of the drain pipe 4 inside the connecting section 2 extends into the branch section 3, and the lower end of the drain pipe 4 inside the connecting section 2 extends into the main branch section 1. The drain pipe 4 inside the connecting section 2 extends into both ends of the main branch section 1 and the branch section 3, which facilitates the welding operator to perform welding operations on the joint of the drain pipe 4 through the welding window 5.

[0050] Furthermore, in step one, an airtightness check is performed before each section of drainage pipe 4 is placed into the main branch section 1, connecting section 2, and branch section 3. In steps three, four, and five, a watertightness check is performed after each splicing and welding is completed. Only after the check is confirmed to be qualified can the next welding step or the next process be carried out. After each section is welded, the welding performance and pipeline are checked to prevent the repetition and waste of time, manpower, and material resources caused by discovering problems in the previous process after the next process is completed.

[0051] Furthermore, in step two, the main branch segment 1 is a variable cross-section column with radial dimensions gradually increasing from bottom to top, and each segment of the main branch segment 1 is welded in sections; in step five, the drainage pipes 4 in each segment of the main branch segment 1 are welded together in a top-down order; when the main branch segment 1 is long, the main branch segment 1 is also welded in the same way, first welding the outside and then welding the inside, first welding the upper section and then welding the lower section, to reduce the downward accumulation of gravity and to avoid damage to the drainage pipes 4; when the connecting segment 2 is long, the same segmented welding connection method can also be adopted, which is a top-down, outside-inside welding connection method.

[0052] Furthermore, in step six, a metal corrugated pipe is installed at the weld between the upper opening of the drainage pipe 4 inside the branch section 3 and the roof drainage gutter outlet; the metal corrugated pipe can effectively prevent displacement caused by thermal expansion and contraction and other reasons from affecting the displacement of the roof outlet and the upper opening of the drainage pipe 4 at the top of the Y-shaped column.

[0053] Example

[0054] In this embodiment, taking a newly built terminal building of a large airport in western China as an example, the terminal building has a projected area width exceeding 250 meters and a length exceeding 500 meters. The load-bearing columns of the terminal building adopt octagonal irregular-section steel pipe columns. At the same time, the main branch segment 1 adopts a variable cross-section form along the height direction, the bifurcation of the connecting segment 2 adopts cast steel nodes, and the branch section 3 has a hexagonal to pentagonal bending moment member. The specific form is as follows: Figure 1 As shown.

[0055] This embodiment adopts a novel structural form, in which drainage pipes 4 are respectively laid in multiple internal channels of the hollow Y-shaped column, realizing the integration of architecture, structure and water supply and drainage. The drainage pipes 4 are built into the four cavities of the octagonal steel column, integrating the drainage pipes 4 into the structural system, hiding equipment pipelines on site, and maximizing the clean and limited space effect of the building.

[0056] When welding the main branch section 1, connecting section 2, and branch section 3 in sections, due to factors such as the need for the pipe in connecting section 2 to bend sideways to enter and exit the steel structure, the inability to access the inside of the structure for operation, and the pipe diameter, all drainage pipes 4 inside the steel structure were pre-embedded according to the plan formulated during the steel structure processing. Drainage pipes 4 were prefabricated in the processing plant.

[0057] The maximum length for pre-embedding in steel-concrete composite columns (cross-shaped steel) is 7.5 meters to 20.5 meters, covering two floors. This is because: 1) the horizontal pipes extending from the 7.5-meter floor slab require pre-embedding of the corbel horizontal pipes at the steel component factory; 2) at the 20.5-meter floor, since the octagonal column extends 500mm below the corbel beam, it needs to be pre-embedded at the processing plant. Therefore, the remaining 7.5-14.5-meter floors, according to the overall construction organization control, will be pre-embedded and installed at the steel component factory before being hoisted and assembled on-site.

[0058] Connection scheme for the main branch segment 1 of the Y-shaped steel column: Four steel plates are installed on the steel column panel, with pre-drilled welding holes 500-600mm high. A simulation operation is conducted before construction to determine the accurate process dimensions of the final construction holes.

[0059] Connection scheme between Y-shaped steel components and connecting section 2: Due to the large axial positioning deviation between connecting section 2 and main branch section 1 and branch section 2, the pipe connection of connecting section 2 should consider deviation adjustment.

[0060] Special case of Y-shaped steel component connection with connecting section 2: Due to the fact that some main branch section 1 octagonal columns are connected to cast steel parts 350-380mm above the corbel beam, the splicing of such cast steel parts is completed in the steel component factory, and the corbel is welded after the splicing is completed.

[0061] Welding windows 5 can be opened on both sides of the opposite side or symmetrically on all four sides according to the position of the drain pipe 4. The partition welding hole 9 is used to solve the problem that the drain pipe 4 on the side away from the welding window 5 cannot be welded because the welding window 5 can only be aligned with one side of the drain pipe 4 due to insufficient space in the inner wall of the steel structure. During welding, the welding tool can be inserted through the partition welding hole 9 from the opposite side welding window 5 to weld the inner circumference of the drain pipe 4. After the inner weld is completed, the welding window 5 on the side where the drain pipe 4 is located can be rotated back to weld the outer circumference of the drain pipe 4, thus solving the problem that the drain pipe 4 cannot be rotated and welded in a small space.

[0062] During welding, the upper end of the drain pipe 4 in the connecting section 2 extends into the branch section 3, and the lower end of the drain pipe 4 in the connecting section 2 extends into the main branch section 1; the drain pipe 4 in the connecting section 2 extends into both ends of the main branch section 1 and the branch section 3, making it convenient for welding operators to perform welding operations on the joint of the drain pipe 4 through the welding window 5.

[0063] Weld the drainage pipes 4 in each main branch section 1 in a top-to-bottom order. When the main branch section 1 is long, the main branch section 1 is also welded by first welding the outside and then the inside, and first welding the upper section and then the lower section, to reduce the downward accumulation of gravity and prevent damage to the drainage pipes 4. When the connecting section 2 is long, the segmented welding connection can also be adopted in a top-to-bottom, outside-to-inside welding connection.

[0064] In summary, this invention solves the problem of welding variable cross-section steel Y-shaped columns in large airport terminal buildings with external sections first, then internal sections, and upper sections first, then lower sections. Furthermore, by fixing each section of the drainage pipe after welding, the weight of the drainage pipe accumulates at the bottom, thus preventing it from affecting the welding quality. This addresses the inability to weld variable cross-section steel Y-shaped columns supporting large-span roofs. It also resolves the issue that welding stress and the accumulation of drainage pipe weight significantly impact the welding quality and service life of both the drainage pipe and the variable cross-section steel Y-shaped column. Therefore, this invention has broad application prospects.

[0065] It should be emphasized that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A welding method for Y-shaped columns of variable cross-section steel structures in large-span roofs, characterized in that, Includes the following steps: Step 1: Weld the main branch (1), connecting section (2), and branch section (3) of the variable cross-section steel Y-shaped column according to the design requirements; the main branch (1) is a vertical column section, the connecting section (2) is an inverted "eight" shaped curved section, and the branch section (3) is an upward-branching inclined support column section. The main branch (1), connecting section (2), and branch section (3) are all reserved with movable drainage pipes (4). The two ends of the main branch (1) and branch section (3) are all reserved with welding windows (5) connecting the inside and outside of the pipe wall. Step 2: Hoist and install the main branch section (1), and weld the bottom of the steel section of the main branch section (1) to the pre-embedded base in the ground concrete; hoist and install the connecting section (2), and weld the bottom of the curved section of the connecting section (2) to the top of the steel section of the main branch section (1); hoist and install the branch section (3), and weld the bottom of the steel section of the branch section (3) to the top of the curved section of the connecting section (2); Step 3: Weld the lower end of the drain pipe (4) in the branch section (3) to the upper end of the drain pipe (4) in the connecting section (2) through the welding window (5) at the bottom of the branch section (3). After the welding is completed, fix the drain pipe (4) in the branch section (3) radially to the inner wall of the branch section (3). Step 4: Weld the lower end of the drain pipe (4) in the connecting section (2) to the upper end of the drain pipe (4) in the main branch section (1) through the welding window (5) at the top of the main branch section (1). After the welding is completed, fix the drain pipe (4) in the connecting section (2) radially to the inner wall of the connecting section (2). Step 5: Weld the lower end of the drainage pipe (4) in the main branch section (1) to the drainage interface of the drainage pipe (4) in the pre-embedded base in the ground concrete through the welding window (5) at the bottom of the main branch section (1). After the welding is completed, fix the drainage pipe (4) in the main branch section (1) radially to the inner wall of the main branch section (1). Step 6: Weld the upper opening of the drainage pipe (4) inside the branch section (3) to the drain outlet of the roof drainage gutter through the welding window (5) at the top joint of the branch section (3); Step 7: Conduct airtightness and watertightness checks on the drainage pipes inside the Y-shaped column of the variable cross-section steel structure, and carry out anti-condensation construction. Step 8: Seal the windows of each welded window (5) by welding the steel structure plate; Step 9: System test, overall water tightness check, and after the test is passed, carry out anti-condensation construction on each exposed part.

2. The welding method for Y-shaped columns of variable cross-section steel structures in a large-span roof according to claim 1, characterized in that, In step one, a main branch partition (6) with a cross-section of "+" is fixedly installed in the main branch section (1), and four drainage pipes (4) are evenly distributed in the main branch section (1). A branch partition (7) with a cross-section of "I" is installed in the branch section (3), and two drainage pipes (4) are evenly distributed in the branch section (3).

3. The welding method for Y-shaped columns of variable cross-section steel structures in a large-span roof according to claim 2, characterized in that, In step one, multiple adjustable pipe clamps (8) with adjustable circumference are fixedly installed on the inner wall of the main branch section (1), the inner wall of the connecting section (2), the inner wall of the branch section (3), the main branch partition (6), and the branch partition (7). When the drain pipe (4) passes through the inner cavity of the main branch section (1), the connecting section (2), and the branch section (3), the adjustable pipe clamps (8) are respectively fitted on the outer circumference of the drain pipe (4). In steps three, four, and five, when the drain pipe (4) is fixed radially to the inner wall of each section after welding, it is tightened and connected by the adjustable pipe clamps (8).

4. The welding method for Y-shaped columns of variable cross-section steel structures in a large-span roof according to claim 2, characterized in that, In step one, the main branch partition (6) and the branch partition (7) are provided with radially extending partition welding holes (9), and the opening position of the partition welding holes (9) matches the welding window (5).

5. The welding method for Y-shaped columns of variable cross-section steel structures in a large-span roof according to claim 4, characterized in that, The partition plate around the weld hole (9) of the partition plate is provided with reinforcing ribs (10).

6. The welding method for Y-shaped columns of variable cross-section steel structures in a large-span roof according to claim 1, characterized in that, In step one, both ends of the main branch segment (1) and the branch segment (3) are respectively provided with end caps (11). The end caps (11) seal both ends of the main branch segment (1) and the branch segment (3). The end caps (11) are set perpendicular to the length direction of the drain pipe (4). The end caps (11) are provided with circular cap holes (12) through which the drain pipe (4) passes.

7. The welding method for Y-shaped columns of variable cross-section steel structures in a large-span roof according to claim 6, characterized in that, In step one, the two ends of the drain pipe (4) in the connecting section (2) extend out of the upper and lower ends of the steel structure of the connecting section (2). During welding, the upper end of the drain pipe (4) in the connecting section (2) extends into the branch section (3), and the lower end of the drain pipe (4) in the connecting section (2) extends into the main branch section (1).

8. The welding method for Y-shaped columns of variable cross-section steel structures in a large-span roof according to claim 1, characterized in that, In step one, an airtightness check is performed before each section of drainage pipe (4) is placed into the main branch section (1), connecting section (2), and branch section (3). In steps three, four, and five, a watertightness check is performed after each splicing and welding is completed. Only after the check is confirmed to be qualified can the next welding step or the next process be carried out.

9. The welding method for Y-shaped columns of variable cross-section steel structures in a large-span roof according to claim 1, characterized in that, In step two, the main branch section (1) is a variable cross-section column with radial dimensions gradually increasing from bottom to top, and the variable cross-section columns of the main branch section (1) are welded in sections; in step five, the drainage pipes (4) in each section of the main branch section (1) are welded together in a top-to-bottom order.

10. The welding method for Y-shaped columns of variable cross-section steel structures in a large-span roof according to claim 1, characterized in that, In step six, a metal corrugated pipe is installed at the weld between the upper opening of the drainage pipe (4) in the branch section (3) and the roof drainage gutter outlet.

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