T-type corrosion-resistant pipe truss joint structure and construction method thereof

Abstract

This invention relates to the field of steel structure technology, specifically to a T-type corrosion-resistant pipe truss node structure and its construction method, including a composite pipe main, branch pipes, internal stiffening arc plates, layered welds, and openings. Useful openings are provided on the sidewalls of the composite pipe main. Low-cost, high-strength carbon steel is used as the core load-bearing frame, replacing expensive full-section stainless steel components. This significantly reduces project costs while ensuring corrosion resistance. Through an innovative design of "circumferential bevel + internal stiffening arc plate," the branch pipes pass over the weak outer stainless steel pipe, achieving full penetration and full welds with both metal pipes. This construction process allows pull-out loads to be directly transferred to the internal carbon steel, effectively avoiding outer skin tearing and interlayer delamination. It ensures both direct load transfer to the internal carbon steel core and continuous surface corrosion resistance, making it suitable for structural engineering in highly corrosive environments such as coastal and marine engineering projects.

Description

Technical Field

[0001] This invention relates to the field of steel structure technology, specifically to a T-shaped corrosion-resistant pipe truss joint structure and its construction method. Background Technology

[0002] Tubular truss structures have advantages such as light weight, high stiffness, high efficiency in force transmission, and beautiful appearance. They are widely used in engineering scenarios such as large-span stadiums, cross-sea bridges, offshore platforms, and coastal industrial plants. T-shaped intersecting nodes, as the most basic connection form of tubular trusses, are the core hub for the transmission of internal forces in the truss and directly determine the overall safety and durability of the structure. In corrosive environments such as marine, coastal, chemical, and high-humidity and high-salt environments, T-shaped nodes face the dual risk of failure due to corrosion degradation and stress concentration. Traditional T-shaped tubular truss nodes are mainly based on direct intersecting welding, which has problems such as poor corrosion resistance, limited mechanical properties, and high difficulty in construction and maintenance. At present, no T-shaped corrosion-resistant tubular truss node structure and its construction method have been found.

[0003] The invention patent application CN202410449081.7 discloses an anti-corrosion bolt ball joint and its construction method. It discloses sealing the gap between the connecting components and the bolt ball / rod by setting a sealing layer, effectively preventing moisture from entering the gap and causing corrosion at the joint. Simultaneously, the invention uses a protective structure to prevent moisture from entering the sealing layer and the end cap of the rod, forming a double protective barrier. This effectively protects the sealing layer from damage and completely blocks moisture from contacting the bolt ball joint, thus significantly improving the sealing reliability and anti-corrosion performance of the joint. However, it relies on multiple layers of flexible polymer materials for physical wrapping, which carries the risk of material aging and failure, and the inability to achieve long-term anti-corrosion. The cumbersome on-site pouring and light curing processes reduce construction efficiency, and the overall stiffness of the bolted joint is relatively low.

[0004] The invention patent with application number CN202510678304.1 discloses a stainless steel beam-column joint and its construction method suitable for marine island and reef environments. It discloses that stainless steel sleeves restrain the expansion of precast columns, stainless steel reinforcement enhances the bending and shear resistance, and I-shaped profiles improve the shear resistance of the joint, thus optimizing the stress. The stainless steel material and the all-steel-free design effectively resist seawater corrosion. The beam support also functions as a formwork, and the bolted and anchored connection simplifies construction, making it suitable for rapid assembly in marine island and reef environments. However, the use of pure stainless steel results in high costs. The pull-out bearing capacity of the mixed interface of the glue bolts and grout is limited, and the wet operation on site severely restricts work efficiency. In addition, the joint has a complex shape and deteriorated aerodynamic shape, making it difficult to adapt to large-span spatial intersecting truss systems.

[0005] The invention patent application CN202311516286.4 discloses a K-type steel pipe intersecting joint structure and its construction method. It discloses a method that welds two branch pipes as a whole to the main pipe using upper and lower external arc stiffening plates and external stiffening end plates. This increases the stress-bearing area of ​​the main and branch pipe welds, improves the joint stiffness, and reduces the stress generated by in-plane bending moments, out-of-plane bending moments, and uneven axial forces between the branch pipes. Multiple internal stiffening transverse diaphragms and two internal stiffening longitudinal ribs improve the unevenness of stress at the intersection line. This combination of internal and external stiffening improves the static bearing capacity of the stiffened K-type steel pipe intersecting joint under complex internal force conditions, reduces the fatigue stress amplitude of the intersecting joint, and extends the fatigue life of the joint. However, the accessibility of welding the internal stiffening components is poor; the external plates degrade the aerodynamic shape of the joint, and abrupt changes in end stiffness can easily induce fatigue cracks; simultaneously, the complex structural dead angles are prone to crevice corrosion, lacking a long-term anti-corrosion closed loop.

[0006] Traditional tubular trusses made entirely of carbon steel incur extremely high costs for corrosion protection and maintenance; those made entirely of stainless steel are prohibitively expensive. A bimetallic composite pipe structure with an outer layer of stainless steel and an inner layer of carbon steel balances mechanical properties, corrosion resistance, and cost-effectiveness. However, the outer stainless steel wall thickness of the main pipe is relatively small. When branch pipes are directly welded to the outer surface of the main pipe, under immense tensile loads, the outer stainless steel cladding is prone to delamination or tearing between the inner carbon steel base layer and the outer layer. Furthermore, if the arc penetrates the stainless steel layer to directly melt the inner carbon steel in pursuit of full penetration, the direct mixing of dissimilar metals easily generates brittle martensitic structures at the fusion line, leading to cold cracking during welding. Therefore, a T-shaped corrosion-resistant tubular truss node structure and its construction method are proposed. Summary of the Invention

[0007] In order to solve the technical problems existing in the prior art, the present invention provides a T-type corrosion-resistant pipe truss node structure and its construction method.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a T-type corrosion-resistant pipe truss node structure and its construction method, comprising a composite pipe main, a branch pipe, an inner stiffening arc plate, layered welds and openings, wherein a useful opening is provided on the side wall of the composite pipe main, an inner stiffening arc plate is fixed on the inner wall of the composite pipe main inside the opening, a branch pipe is inserted inside the opening, and one end of the branch pipe that penetrates into the interior of the composite pipe main is fixed to the outer surface of the inner stiffening arc plate.

[0009] Preferably, the composite pipe main includes an inner carbon steel pipe and an outer stainless steel pipe, wherein the inner surface of the outer stainless steel pipe is bonded to the outer surface of the inner carbon steel pipe through a metallurgical bonding surface formed by composite processes such as hot rolling, hot extrusion or explosion.

[0010] Preferably, the branch pipe is made of the same material as the main composite pipe or a single-layer stainless steel pipe, and both the branch pipe and the main composite pipe are round steel pipes.

[0011] Preferably, the connection between the branch pipe and the main composite pipe and the inner stiffening arc plate is fixed by layered welds.

[0012] Preferably, the curvature of the outer wall of the inner stiffening arc plate is the same as the curvature of the inner wall of the composite pipe main tube, and the size of the inner stiffening arc plate is larger than the size of the opening, completely covering the opening and meeting the welding requirements.

[0013] Preferably, the layered weld includes a root pass, a fill pass, and a cap pass from the inside out. The root pass is located at the end of the branch pipe and on the outer wall of the inner stiffening arc plate. The fill pass fills the opening outside the root pass, and the cap pass covers the fill pass.

[0014] Preferably, the edge of the filler weld is located on the outer wall of the main composite pipe.

[0015] Preferably, the diameter of the opening is at least 2 mm larger than the diameter of the outer wall of the branch pipe, and a circumferential bevel is formed on the outer edge of the opening, which cuts through the pipe wall of the composite pipe to expose the inner carbon steel pipe.

[0016] Preferably, the root pass weld uses a dissimilar steel welding material with a higher chromium-nickel content than the base material; the fill pass weld and the cap pass weld use welding materials of the same material as the branch pipe.

[0017] A construction method for a T-type corrosion-resistant pipe truss joint structure includes the following steps:

[0018] S1, make a hole at the intersection of the main pipe and the branch pipe. The hole diameter is more than 2mm larger than the outer diameter of the branch pipe to facilitate construction, installation and welding. The hole wall is ground into a circumferential bevel for welding.

[0019] S2, Weld the inner stiffening arc plate to the inner wall of the composite pipe main tube at the opening to ensure deep fusion between the inner stiffening arc plate and the inner wall of the composite pipe main tube, and to disperse stress;

[0020] S3, insert the branch pipe into the opening and lock it against the surface of the inner stiffening arc plate. Use a root pass weld to weld the branch pipe to the inner stiffening arc plate to ensure the transfer of node load.

[0021] S4 employs a segmented symmetrical skip welding process, sequentially welding the filler weld and the cap weld from the inside out. The width of the cap weld is greater than the opening width of the circumferential bevel, ensuring that the cap weld completely overlaps the outer stainless steel surface, forming an isolation and sealing layer.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. This invention uses low-cost, high-strength carbon steel as the core load-bearing frame, replacing expensive full-section stainless steel components. While ensuring corrosion resistance, it significantly reduces the project cost. Through the innovative design of "circumferential bevel + internal stiffening arc plate", the branch pipe passes through the thin outer stainless steel pipe and achieves full penetration and full weld with the two metal pipes. This construction process allows the pull-out load to be directly transferred to the internal carbon steel, effectively avoiding outer skin tearing and interlayer peeling damage. It can ensure that the load is directly transferred to the internal carbon steel core and ensure the continuity of surface corrosion resistance. It is suitable for structural engineering fields with high corrosion environments such as coastal and marine engineering.

[0024] 2. This invention achieves a "zero-gap" fit between the branch pipe and the main pipe through layered welds. Combined with bottom root pass welding, it effectively prevents the carbon steel substrate from diluting the stainless steel weld composition, avoiding the formation of brittle martensitic structures, effectively eliminating the risk of cracking, and preventing defects in welding dissimilar steels. Furthermore, the surface cap weld not only provides structural reinforcement but also completely encapsulates the bevel cut as a corrosion-resistant shield. The entire outer surface of the joint is made of stainless steel, effectively ensuring the long-term corrosion resistance of the component. Attached Figure Description

[0025] Figure 1 This is a schematic diagram showing the disassembly of the truss node of the present invention;

[0026] Figure 2 This is a schematic cross-sectional view of a partial structure of the tubular truss node after construction according to the present invention.

[0027] Figure 3 This is a schematic diagram of the structure of the composite pipe main tube of the present invention;

[0028] Figure 4 This is a schematic cross-sectional view of the tubular truss node after construction according to the present invention.

[0029] Figure 5 This is a cross-sectional structural diagram from another perspective after the construction of the tubular truss node of the present invention.

[0030] The numbers in the image represent:

[0031] 1. Composite main pipe; 11. Inner carbon steel pipe; 12. Outer stainless steel pipe; 2. Branch pipe; 3. Internal stiffening arc plate; 4. Layered weld; 41. Root pass weld; 42. Fill pass weld; 43. Cap pass weld; 5. Opening; 6. Circumferential bevel. Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments, which illustrate the above and other technical features and advantages of the present invention. However, the following embodiments are merely preferred embodiments of the present invention and are not exhaustive.

[0033] Example:

[0034] like Figure 1-5 As shown, the present invention provides a T-type corrosion-resistant pipe truss node structure and its construction method, including a composite pipe main 1, a branch pipe 2, an inner stiffening arc plate 3, a layered weld 4, and an opening 5. The composite pipe main 1 has a useful opening 5 on its side wall. The inner stiffening arc plate 3 is fixed on the inner wall of the composite pipe main 1 inside the opening 5. The branch pipe 2 is inserted into the opening 5. One end of the branch pipe 2 that penetrates into the interior of the composite pipe main 1 is fixed to the outer surface of the inner stiffening arc plate 3. The connection between the branch pipe 2 and the composite pipe main 1 and the inner stiffening arc plate 3 is fixed by the layered weld 4.

[0035] In this embodiment, the composite pipe main 1 includes an inner carbon steel pipe 11 and an outer stainless steel pipe 12. The metallurgical bonding surface formed on the inner surface of the outer stainless steel pipe 12 by composite processes such as hot rolling, hot extrusion or explosion is bonded to the outer surface of the inner carbon steel pipe 11.

[0036] In this embodiment, the branch pipe 2 is made of the same material as the main composite pipe 1 or a single-layer stainless steel pipe, and both the branch pipe 2 and the main composite pipe 1 are round steel pipes.

[0037] In this embodiment, the curvature of the outer wall of the inner stiffening arc plate 3 is the same as the curvature of the inner wall of the composite pipe main tube 1, and the size of the inner stiffening arc plate 3 is larger than the size of the opening 5, completely covering the opening and meeting the welding requirements.

[0038] In this embodiment, the layered weld 4 includes, from the inside out, a root pass 41, a fill pass 42, and a cover pass 43. The root pass 41 uses high-alloy transition layer welding material in conjunction with tungsten inert gas welding. The fill pass 42 uses stainless steel filler material for multi-layer, multi-pass welding. The cover pass 43 uses pure austenitic stainless steel welding material. The same metal welding mechanism is used to achieve a perfect seal of the outer shell. The root pass 41 is located at the end of the branch pipe 2 and on the outer wall of the inner stiffening arc plate 3. The fill pass 42 fills the opening 5 outside the root pass 41. The cover pass 43 covers the fill pass 42. The edge of the fill pass 42 is located on the outer wall of the composite pipe main 1.

[0039] In this embodiment, the diameter of the opening 5 is at least 2 mm larger than the diameter of the outer wall of the branch pipe 2. A circumferential bevel 6 is provided on the outer edge of the opening 5. The circumferential bevel 6 cuts through the pipe wall of the composite pipe 1, exposing the inner carbon steel pipe 12.

[0040] In this embodiment, the root pass 41 is made of dissimilar steel welding material with a higher chromium-nickel content than the base material; the fill pass 42 and the cap pass 43 are made of the same welding material as the branch pipe 2.

[0041] The specific construction method is as follows: A hole is made at the intersection of the main composite pipe 1 and the diameter of the hole is more than 2mm larger than the outer diameter of the branch pipe 2 to facilitate construction, installation and welding. The hole wall is ground into a circumferential bevel 6 for welding. The inner stiffening arc plate 3 is welded to the inner wall of the main composite pipe 1 at the opening 5 using full-circumferential fillet welding, high alloy transition layer welding material and tungsten inert gas welding process, to ensure that the inner stiffening arc plate 3 and the inner wall of the main composite pipe 1 are deeply fused and the stress is dispersed. The branch pipe 2 is inserted into the opening 5 and abuts and locks against the surface of the inner stiffening arc plate 3. The branch pipe 2 and the inner stiffening arc plate 3 are welded using the root pass 41 to ensure the load transfer at the node. The fill pass 42 and the cap pass 43 are welded from the inside to the outside using a segmented symmetrical skip welding process. The width of the cap pass 43 is greater than the opening width of the circumferential bevel 6 so that the cap pass 43 is completely overlapped on the surface of the outer stainless steel 12 to form an isolation and sealing layer.

[0042] The above description is merely a preferred embodiment of the present invention and is illustrative rather than restrictive. Those skilled in the art will understand that many changes, modifications, and even equivalents can be made within the spirit and scope defined by the claims of the present invention, all of which will fall within the protection scope of the present invention.

Claims

1. A T-shaped corrosion-resistant pipe truss joint structure, characterized in that, It includes a composite pipe main (1), a branch pipe (2), an inner stiffening arc plate (3), a layered weld (4), and an opening (5). The composite pipe main (1) has a useful opening (5) on its side wall. The inner stiffening arc plate (3) is fixed on the inner wall of the composite pipe main (1) inside the opening (5). The branch pipe (2) is inserted inside the opening (5). One end of the branch pipe (2) that penetrates into the interior of the composite pipe main (1) is fixed on the outer surface of the inner stiffening arc plate (3).

2. The T-type corrosion-resistant pipe truss node structure as described in claim 1, characterized in that, The composite main pipe (1) includes an inner carbon steel pipe (11) and an outer stainless steel pipe (12). The inner surface of the outer stainless steel pipe (12) is bonded to the outer surface of the inner carbon steel pipe (11) through a metallurgical bonding surface formed by the composite process.

3. The T-type corrosion-resistant pipe truss node structure as described in claim 1, characterized in that, The branch pipe (2) is made of the same material as the main composite pipe (1) or a single-layer stainless steel pipe. Both the branch pipe (2) and the main composite pipe (1) are round steel pipes.

4. The T-type corrosion-resistant pipe truss node structure as described in claim 1, characterized in that, The branch pipe (2) is fixed to the main composite pipe (1) and the inner stiffening arc plate (3) by a layered weld (4).

5. The T-type corrosion-resistant pipe truss node structure as described in claim 1, characterized in that, The curvature of the outer wall of the inner stiffening arc plate (3) is the same as the curvature of the inner wall of the composite pipe main (1). The size of the inner stiffening arc plate (3) is larger than the size of the opening (5), completely covering the opening and meeting the welding requirements.

6. The T-type corrosion-resistant pipe truss node structure as described in claim 4, characterized in that, The layered weld (4) includes, from the inside out, a root pass (41), a fill pass (42), and a cover pass (43). The root pass (41) is located at the end of the branch pipe (2) and on the outer wall of the inner stiffening arc plate (3). The fill pass (42) fills the opening (5) outside the root pass (41), and the cover pass (43) covers the fill pass (42).

7. The T-type corrosion-resistant pipe truss node structure as described in claim 6, characterized in that, The edge of the filler weld (42) is located on the outer wall of the composite pipe main (1).

8. The T-type corrosion-resistant pipe truss node structure as described in claim 2, characterized in that, The diameter of the opening (5) is at least 2 mm larger than the diameter of the outer wall of the branch pipe (2). A circumferential bevel (6) is provided on the outer edge of the opening (5). The circumferential bevel (6) cuts through the pipe wall of the composite pipe (1) and exposes the inner carbon steel pipe (12).

9. The T-type corrosion-resistant pipe truss node structure as described in claim 5, characterized in that, The root pass (41) uses dissimilar steel welding material with a higher chromium-nickel content than the base material; the fill pass (42) and the cover pass (43) use welding material of the same material as the branch pipe (2).

10. A construction method for a T-shaped corrosion-resistant pipe truss joint structure, characterized in that, The method applied to the node construction as described in claims 1-9 includes the following steps: S1, make a hole at the intersection of the main pipe (1) and the diameter of the hole is more than 2mm larger than the outer diameter of the branch pipe (2) to facilitate construction, installation and welding. The hole wall is ground into a circumferential bevel (6) for welding. S2, weld the inner stiffening arc plate (3) onto the inner wall of the composite pipe main (1) at the opening (5) to ensure that the inner stiffening arc plate (3) and the inner wall of the composite pipe main (1) are deeply fused together and the stress is dispersed; S3, insert the branch pipe (2) into the opening (5) and lock it against the surface of the inner stiffening arc plate (3). Use the root pass weld (41) to weld the branch pipe (2) to the inner stiffening arc plate (3) to ensure the transfer of node load; S4, the filler weld (42) and cover weld (43) are welded sequentially from the inside to the outside using a segmented symmetrical skip welding process; wherein, the welding width of the cover weld (43) is greater than the opening width of the circumferential bevel (6), so that the cover weld (43) is completely overlapped on the surface of the outer stainless steel (12) to form an isolation and sealing layer.

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