Punching and grouting reinforcement method for welding hollow sphere joint

Abstract

The invention discloses a punching and grouting reinforcement method for welding a hollow sphere joint, and relates to the technical field of steel structure reinforcement. The PET structure foaming material is poured into the hollow ball, the section rigidity and the overall bearing capacity of the hollow ball can be remarkably improved, after grouting, a solid filling body is formed in the hollow ball, loads can be transmitted more evenly, local stress concentration is reduced, and failure caused by local deformation or cracking of the joint is avoided; the grouting material can fill gaps in the hollow balls, prevents water and corrosive media from invading, slows down corrosion of steel and prolongs the service life of joints. And different anti-corrosion grouting materials can be selected according to the environment, so that the anti-corrosion capability is further improved.

Description

Technical Field

[0001] The invention relates to the technical field of steel structure reinforcement, in particular to a punching and grouting reinforcement method for welded hollow spherical nodes. Background Art

[0002] Key nodes in existing large-span spatial structures serve as the core for load transmission, and their safety directly determines the overall structure's load-bearing performance and durability. Welded hollow spherical nodes, as the core load-transmitting components of large-span spatial structures, play a crucial role in load transfer and force distribution within trusses and grid systems. As structures age, nodes are subject to repeated loads and environmental erosion, making them susceptible to hazards such as weld cracking, weakened spherical wall thickness, and loose connections. Therefore, reinforcement measures are necessary for welded hollow spherical nodes.

[0003] There are various methods for reinforcing welded hollow sphere nodes. Repair welding is used to re-weld cracked welds, but high temperatures can easily generate new stress concentrations, and the welding process is demanding. Although external sleeves can assist in force transmission and improve bearing capacity, the curved surface of the hollow sphere makes it difficult to fit the sleeves, and if the fit is not good, it will affect force transmission. Adhesive carbon fiber cloth reinforcement uses its high strength to strengthen the node, but environmental factors such as moisture and oil can easily weaken the bonding strength, and long-term use can easily age the joint, which will reduce the reinforcement effect. Adding stiffening ribs can improve the stiffness and bearing capacity of the node, but the external addition will affect the appearance, and if the stiffening ribs are not arranged properly, the expected reinforcement goal cannot be achieved.

[0004] Therefore, a new solution to the above problems needs to be proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a punching and grouting reinforcement method for welded hollow sphere nodes. When local defects or insufficient bearing capacity occur in the welded hollow sphere nodes, grouting material is injected into the interior of the sphere to fill the gaps, significantly improving the bearing capacity and fatigue resistance of the structure, thereby solving the technical problems raised in the background technology.

[0006] To achieve the above-mentioned object, the present invention provides the following technical solution: a punching and grouting reinforcement method for welded hollow spherical nodes, comprising at least the following steps:

[0007] S1: Drill exhaust holes and grouting holes for the on-site welded hollow balls, clean the rust in the holes and the surface dust, ensure the accuracy of the holes and the cleanliness of the hollow balls, and use welded hollow balls and several steel pipes to form welded hollow ball nodes;

[0008] S2: Evenly spray epoxy resin interface agent inside the welded hollow ball and let it stand for 2 hours to solidify, in preparation for enhancing the bonding strength between PET structural foam and steel;

[0009] S3: Install grouting pipe and exhaust pipe;

[0010] S4: PET structural foam is introduced into the cavity through the grouting pipe in two stages, and the air is discharged from the exhaust pipe;

[0011] S5: After the curing is completed, the grouting pipe and exhaust pipe are removed and the excess foam at the exhaust hole is cut;

[0012] S6: Use epoxy resin putty to seal the vent holes and grouting holes to form a first epoxy resin putty sealing hole and a second epoxy resin putty sealing hole, ensuring that the surface of the sealing hole is smooth.

[0013] Furthermore, the S4 at least includes the following steps:

[0014] First, preheat the welded hollow balls to 70-75°C evenly to reduce the viscosity of the foaming material and prevent the cold balls from causing foam shrinkage.

[0015] Then the first stage of pouring is carried out, in which the cavity in the welded hollow ball is preliminarily filled with foaming material;

[0016] Finally, carry out the second stage of grouting, open the valve at the grouting pipe, inject the remaining foaming material, close the valve at the grouting pipe, and wait for the final foaming and curing.

[0017] Furthermore, a grouting hole is provided at the lowest point of the bottom of the welded hollow ball and away from the weld area, and an exhaust hole is provided at the highest point of the top of the welded hollow ball and coaxially with the grouting hole to ensure the requirements of "low-position grouting and high-position exhaust".

[0018] Furthermore, the exhaust pipe is installed at a position corresponding to the exhaust hole. The exhaust pipe is transparent. During the grouting process, observation is performed through the exhaust pipe. When a small amount of overflowing grout appears in the exhaust pipe, it indicates that the grouting is completed.

[0019] Furthermore, the grouting pipe is provided with an on-off valve, and the valve needs to be closed after the two stages of grouting are completed.

[0020] Furthermore, the PET structural foaming material includes mixed foaming material A and mixed foaming material B;

[0021] The mixed foaming material A is a resin;

[0022] The mixed foaming material B is one or more of a curing agent and a foaming agent;

[0023] The ratio of the mixed foaming material A to the mixed foaming material B is adjusted as required.

[0024] Furthermore, the injection volume algorithm of the first stage perfusion is as follows:

[0025] Injection volume = (sphere volume × 60%) ÷ foaming expansion rate

[0026] The volume of the PET structural foam material expands by 1.4 to 1.6 times during the foaming process.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. This invention significantly increases the cross-sectional rigidity and overall load-bearing capacity of the hollow sphere by injecting PET structural foam into the interior of the hollow sphere. After injection, a solid filling body is formed inside the hollow sphere, which can more evenly transfer the load, reduce local stress concentration, and avoid failure of the node due to local deformation or cracking.

[0029] 2. The grouting material of the present invention can fill the internal voids of the hollow spheres, block the intrusion of moisture and corrosive media, slow down steel corrosion, and extend the life of the joints. Different anti-corrosion grouting materials can be selected according to the environment to further enhance the corrosion resistance;

[0030] 3. The punching and grouting reinforcement method of the present invention significantly reduces the risk of thermal damage by avoiding welding operations, while simplifying the construction process, reducing costs and improving construction safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 It is an overall schematic diagram of the present invention;

[0033] Figure 2 It is a schematic diagram of a welded hollow sphere node of the present invention;

[0034] Figure 3 This is a schematic diagram of the exhaust hole on the top of the welded hollow sphere node of the present invention;

[0035] Figure 4 This is a perspective view showing double holes of a hollow sphere in a welded hollow sphere node of the present invention;

[0036] Figure 5 It is a three-dimensional cross-sectional view of the welded hollow sphere node after punching of the present invention;

[0037] Figure 6 It is a three-dimensional cross-sectional view of the welded hollow sphere node after punching and grouting of the present invention;

[0038] Figure 7 This is a schematic diagram of the welded hollow sphere node after sealing and reinforcement is completed.

[0039] In the figure: 1. Welded hollow ball; 2. Steel pipe; 3. Exhaust hole; 4. Grouting hole; 5. Exhaust pipe; 6. Grouting pipe; 7. PET structural foam; 8. First epoxy resin putty sealing; 9. Second epoxy resin putty sealing. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0041] See also Figure 1-Figure 7 A punching and grouting reinforcement method for welded hollow spherical nodes comprises at least the following steps:

[0042] S1: Drill exhaust holes 3 and grouting holes 4 for the on-site welded hollow ball 1, clean the rust in the holes and the surface dust, ensure the accuracy of the holes and the neatness of the hollow ball, and use the welded hollow ball 1 and several steel pipes 2 to form a welded hollow ball node;

[0043] S2: Evenly spray epoxy resin interface agent inside the welding hollow ball 1 and let it stand for 1 hour to solidify in preparation for enhancing the bonding strength between the PET structural foam and the steel;

[0044] S3: Install the grouting pipe 6 and the exhaust pipe 5;

[0045] S4: The PET structural foam material 7 is introduced into the cavity through the grouting pipe 6 in two stages, and the air is discharged from the exhaust pipe 5;

[0046] S5: After the curing is completed, the grouting pipe 6 and the exhaust pipe 5 are removed, and the excess foam at the exhaust hole 3 is cut;

[0047] S6: Use epoxy resin putty to seal the exhaust hole 3 and the grouting hole 4 to form a first epoxy resin putty sealing hole 8 and a second epoxy resin putty sealing hole 9, ensuring that the surface of the sealing hole is smooth.

[0048] S4 includes at least the following steps:

[0049] First, preheat the welded hollow ball 1 to 70°C–75°C uniformly to reduce the viscosity of the foaming material and prevent the cold ball from causing foam shrinkage.

[0050] Then, the first stage of pouring is carried out, in which the cavity in the welded hollow ball 1 is preliminarily filled with a foaming material;

[0051] Finally, the second stage of grouting is carried out, the valve at grouting pipe 6 is opened, the remaining foaming material is injected, the valve at grouting pipe 6 is closed, and the final foaming and curing are waited for.

[0052] A grouting hole 4 is opened at the lowest point of the bottom of the welded hollow ball 1 and away from the weld area, and an exhaust hole 3 is opened at the highest point of the top of the welded hollow ball 1 and coaxial with the grouting hole 4 to ensure the requirements of "low-position grouting and high-position exhaust".

[0053] The exhaust pipe 5 is installed at the position corresponding to the exhaust hole 3. The exhaust pipe 8 is transparent. During the grouting process, observation is made through the exhaust pipe 5. When a small amount of grout overflows in the exhaust pipe 5, it indicates that the grouting is completed.

[0054] An on-off valve is provided at grouting pipe 6, and the valve needs to be closed after the two stages of grouting are completed.

[0055] The PET structural foam material 7 includes mixed foam material A and mixed foam material B;

[0056] The mixed foaming material A is resin;

[0057] The mixed foaming material B is one or more of a curing agent and a foaming agent;

[0058] The ratio of mixed foaming material A and mixed foaming material B is adjusted as required.

[0059] The injection volume algorithm for the first stage of perfusion is as follows:

[0060] Injection volume = (sphere volume × 60%) ÷ foaming expansion rate

[0061] The volume of the PET structural foam material 7 expands by 1.4 to 1.6 times during the foaming process.

[0062] After the PET structural foaming material 7 is poured to form solid foam, the welded hollow ball 1 becomes a solid structure. According to calculations, the weight of the welded hollow balls with diameters of 300mm, 500mm, 700mm, and 900mm and corresponding thicknesses of 10mm, 14mm, 20mm, and 30mm respectively increases by 8.45%, 10.11%, 9.88%, and 8.34% after reinforcement is completed.

[0063] By injecting PET structural foam into the hollow sphere to form a foam material, the cross-sectional stiffness and overall load-bearing capacity of the hollow sphere can be significantly increased. After grouting, a solid filling mass is formed inside the hollow sphere, which can more evenly transfer loads, reduce local stress concentration, and prevent failure of nodes due to localized deformation or cracking. The grouting material fills the internal voids of the hollow sphere, blocking the intrusion of moisture and corrosive media, slowing steel corrosion, and extending the life of the node. Different anti-corrosion grouting materials can be selected according to the environment to further enhance corrosion resistance. The punch grouting reinforcement method significantly reduces the risk of thermal damage by avoiding welding operations, while also simplifying the construction process, reducing costs, and improving construction safety.

[0064] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A punching and grouting reinforcement method for welded hollow spherical nodes, characterized in that: At least the following steps are included: S1: Drilling an exhaust hole (3) and a grouting hole (4) for the on-site welded hollow ball (1), and cleaning the rust in the hole and the surface dust to ensure the accuracy of the hole and the neatness of the hollow ball, and using the welded hollow ball (1) and several steel pipes (2) to form a welded hollow ball node; S2: Evenly spray epoxy resin interface agent inside the welding hollow ball (1) and let it stand for 1 hour to solidify in preparation for enhancing the bonding strength between the PET structural foam and the steel; S3: Install the grouting pipe (6) and the exhaust pipe (5); S4: The PET structural foam material (7) is introduced into the cavity through the grouting pipe (6) in two stages, and the air is discharged from the exhaust pipe (5); S5: After curing is completed, the grouting pipe (6) and the exhaust pipe (5) are removed, and the excess foam at the exhaust hole (3) is cut; S6: Use epoxy resin mortar to seal the vent hole (3) and the grouting hole (4) to form a first epoxy resin mortar sealing hole (8) and a second epoxy resin mortar sealing hole (9), ensuring that the surface of the sealing hole is smooth.

2. A punching and grouting reinforcement method for welded hollow spherical nodes according to claim 1, characterized in that: The S4 at least includes the following steps: First, preheating is performed to uniformly heat the welded hollow ball (1) to 70°C–75°C in order to reduce the viscosity of the foaming material and prevent the cold ball from causing foam shrinkage; Then, the first stage of pouring is carried out, wherein the cavity in the welded hollow ball (1) is preliminarily filled with a foaming material; Finally, the second stage of grouting is carried out, the valve at the grouting pipe (6) is opened, the remaining foaming material is injected, and the valve at the grouting pipe (6) is closed to wait for the final foaming and solidification.

3. The punching and grouting reinforcement method for welded hollow spherical nodes according to claim 1, characterized in that: A grouting hole (4) is provided at the lowest point of the bottom of the welded hollow ball (1) and away from the weld area, and an exhaust hole (3) is provided at the highest point of the top of the welded hollow ball (1) and coaxially with the grouting hole (4).

4. The punching and grouting reinforcement method for welded hollow spherical nodes according to claim 1, characterized in that: The exhaust pipe (5) is installed at a position corresponding to the exhaust hole (3). The exhaust pipe (8) is transparent. During the grouting process, observation is performed through the exhaust pipe (5). When a small amount of grout overflows in the exhaust pipe (5), it indicates that the grouting is completed.

5. The punching and grouting reinforcement method for welded hollow spherical nodes according to claim 1, characterized in that: The grouting pipe (6) is provided with an on-off valve, and the valve needs to be closed after the two stages of grouting are completed.

6. The punching and grouting reinforcement method for welded hollow spherical nodes according to claim 1, characterized in that: The PET structural foaming material (7) comprises a mixed foaming material A and a mixed foaming material B; The mixed foaming material A is a resin; The mixed foaming material B is one or more of a curing agent and a foaming agent; The ratio of the mixed foaming material A to the mixed foaming material B is adjusted as required.

7. The punching and grouting reinforcement method for welded hollow spherical nodes according to claim 2, characterized in that: The injection volume algorithm for the first stage of perfusion is as follows: Injection volume = (sphere volume × 60%) ÷ foaming expansion rate The volume of the PET structural foaming material (7) expands by 1.4 to 1.6 times during the foaming process.

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