Modular reinforcement device and method for opening a hole in a concrete structure beam

Abstract

The application provides a modular reinforcing device and method for opening a large hole in a concrete structure beam, wherein the reinforcing device comprises a prefabricated split steel sleeve assembly and a welded U-shaped hoop plate module; the prefabricated split steel sleeve assembly comprises four L-shaped steel plates, each of which is provided with a convex rib on the outer side, and the four L-shaped steel plates are combined into an annular constraint sleeve through bolts; the welded U-shaped hoop plate module is a U-shaped frame formed by welding a bottom plate and two vertical plates, the vertical plates are provided with anchor bolt holes, and the outer sides of the two vertical plates are symmetrically welded with stiffened steel plates; and the concrete beam is provided with preset glue injection holes. Through the prefabricated assembly design and the standardized construction process, the application realizes efficient assembly and reliable stress of the reinforcing structure, and meets the safety requirements of building reconstruction projects.

Description

Technical Field

[0001] This invention relates to the field of building structure reinforcement technology, specifically to a modular reinforcement device and method for creating large openings in concrete structural beams, applicable to the structural reinforcement of concrete beams in industrial and civil building renovations, pipeline crossings, and other projects. Background Technology

[0002] In building renovation or pipeline laying projects, it is often necessary to create large openings in concrete beams (the opening size usually exceeds 1 / 3 of the beam's cross-sectional height), such as... Figure 1 As shown. However, arbitrarily creating openings significantly weakens the cross-sectional stiffness and load-bearing capacity of concrete beams, leading to the expansion of cracks around the openings, increased beam deformation, and even structural safety accidents. Existing reinforcement techniques mostly employ on-site welding of steel sleeves combined with U-shaped clamps, but these techniques have the following drawbacks:

[0003] 1. Low construction efficiency: Steel sleeves and U-shaped clamps need to be cut and welded on site. Welding accounts for more than 70% of the workload and is significantly affected by ambient temperature and humidity. Welding quality is difficult to guarantee in low-temperature environments.

[0004] 2. Weak interface force transmission: The steel sleeve and concrete are only bonded by structural adhesive, which has insufficient shear stiffness. The measured interface slip can reach 0.3mm, which can easily lead to stress concentration.

[0005] 3. Low modularity: On-site operations rely on manual assembly, the components have poor dimensional accuracy, poor adaptability to irregular openings, and cannot be applied on a large scale.

[0006] Therefore, there is an urgent need for a prefabricated and modular reinforcement device and method to improve construction efficiency and structural safety. Summary of the Invention

[0007] To address the problems of complex construction and poor force transmission at the interface in the reinforcement of large openings in concrete structural beams in existing technologies, this invention provides a modular reinforcement device and method for large openings in concrete structural beams. Through prefabricated component design and standardized construction processes, it achieves efficient assembly and reliable stress bearing of the reinforced structure, meeting the safety requirements of building renovation projects.

[0008] The above-mentioned objectives of the present invention can be achieved through the following technical solutions:

[0009] A modular reinforcement device for large openings in concrete structural beams includes a prefabricated split steel sleeve assembly and a welded U-shaped hoop plate module. The prefabricated split steel sleeve assembly includes four prefabricated L-shaped steel plates (thickness 8-12mm). Each L-shaped steel plate has protruding ribs with a spacing of 50-150mm and a height of 3mm-8mm processed on its outer side. The protruding ribs enhance the mechanical interlocking with the concrete. The four L-shaped steel plates are bolted together to form a ring-shaped constraint sleeve.

[0010] The welded U-shaped hoop plate module is a U-shaped frame welded from a base plate (thickness 8-14mm) and two upright plates (thickness 6-12mm). Anchor bolt holes are opened on the upright plates, and stiffening steel plates (thickness 6-10mm) are symmetrically welded to the outer sides of the two upright plates.

[0011] The concrete beam has pre-drilled injection holes (10mm in diameter, 200mm apart) and vent holes (8mm in diameter). If necessary, these can also be drilled on the steel sleeve and U-shaped hoop to ensure that the adhesive is fully filled.

[0012] Furthermore, fixing pins are provided on both sides of the L-shaped steel plate. The fixing pins ensure assembly accuracy and prevent the expansion of cracks in the opening. Bolt connection holes are opened on the fixing pins. The four L-shaped steel plates are connected and fixed by bolts through the fixing pins. The preload of the bolts is 100-160 N·m.

[0013] Furthermore, several steel washers are fitted in the middle of the bolt, and the length and width of the steel sleeve are adjusted by these steel washers to meet the needs of different sized openings.

[0014] Furthermore, the height of the upright plate is 1.2 to 1.8 times higher than the height of the opening.

[0015] Furthermore, the spacing of the anchor bolt holes is 100-150mm, the diameter d of the chemical anchor bolts is 12-18mm, and the modified epoxy resin structural tube is matched. The anchoring depth is ≥10d (d is the diameter of the chemical anchor bolt), and the design value of the pull-out bearing capacity of a single bolt is ≥10kN.

[0016] Furthermore, modified epoxy resin structural adhesive is injected into the pre-set injection hole, with a bonding strength ≥10MPa, and can be cured in an environment above 5℃.

[0017] Another objective of this invention is to provide a modular reinforcement method for large openings in concrete structural beams, comprising the following steps:

[0018] Finite element analysis was used to determine that the unloading amount was 30%-50% of the design load. The unloading was carried out in stages by hydraulic jacks, with each stage held for 20 minutes, and the displacement deviation was controlled to be ≤3mm. The prefabricated split steel sleeve components and welded U-shaped hoop modules were manufactured in the factory, and the pre-assembly error was ≤2mm.

[0019] Four L-shaped steel plates are embedded into the opening and temporarily fixed with fixing pins. The bolts are tightened in a diagonal sequence to form a ring-shaped constraint sleeve. Several steel shims are set in the middle as needed. The length and width of the steel sleeve are adjusted by these steel shims to meet the needs of openings of different sizes.

[0020] The bottom plate is attached to the bottom surface of the beam, and the vertical plate is welded to the bottom plate with a weld height of ≥6mm. Stiffening steel plates are symmetrically welded to the outside of the vertical plate at a spacing of 200mm to form a three-dimensional stress system.

[0021] Drill holes at the corresponding positions of anchor bolt holes, clean the holes and insert chemical anchor bolts. After curing for 24 hours, conduct a pull-out test. The design value of the pull-out bearing capacity of a single bolt is ≥10kN.

[0022] Inject modified epoxy structural adhesive into the lowest preset injection hole, control the pressure to 0.2-0.3MPa, until no air bubbles overflow from the vent hole, maintain the pressure for 5 minutes and then seal the channel, the adhesive layer thickness is 2-3mm.

[0023] The upper load of the beam was restored in stages (30%→70%→100%), with each stage held for 1 hour. The strain increment was monitored to be ≤30με and the mid-span deflection was ≤L / 400. Finally, a 1.2 times overload test was conducted, and the structure showed no abnormalities after holding the load for 2 hours.

[0024] Furthermore, the preload of the bolts is 100-160 N·m.

[0025] Furthermore, the height of the upright plate is 1.2 to 1.8 times higher than the height of the opening.

[0026] Furthermore, the diameter d of the chemical anchor is 12-18mm, the anchoring depth is ≥10d, and the design value of the pull-out bearing capacity of a single anchor is ≥10kN.

[0027] The beneficial effects of this invention are as follows:

[0028] 1. Prefabricated design: Steel sleeves and U-shaped clamps are prefabricated in the factory, achieving an 85% on-site assembly rate, reducing welding workload by 60%, and increasing construction efficiency by 50%;

[0029] 2. Combined force transmission system: The steel sleeve ribs and structural adhesive form a dual force transmission system of "mechanical interlocking + bonding", which increases the interfacial shear strength by 35%;

[0030] 3. Reinforced structure: The U-shaped hoop plate forms a spatial force-bearing system through the stiffening steel plate, which increases the shear bearing capacity by 30% compared with the traditional process.

[0031] 4. Performance improvement: Flexural bearing capacity is increased by 35%-45%, shear bearing capacity is increased by 25%-35%, and crack width is controlled within 0.1mm;

[0032] 5. Shorter cycle time: 30% shorter than traditional processes, and 20% lower overall cost;

[0033] 6. High adaptability: It can be constructed in environments above 5℃, reducing welding fume emissions by 50%, which meets the requirements of green construction. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of a large opening in a concrete beam;

[0035] Figure 2 This is a schematic diagram of the prefabricated split steel sleeve assembly of the present invention;

[0036] Figure 3 This is a diagram showing the assembly details of the prefabricated split steel sleeve assembly of the present invention;

[0037] Figure 4 This is a schematic diagram of the welded U-shaped hoop plate module of the present invention;

[0038] Figure 5 This is a schematic diagram of the overall structure of the modular reinforcement device of the present invention;

[0039] In the diagram: 1-L-shaped steel plate, 2-protruding rib, 3-bolt, 4-base plate, 5-vertical plate, 6-anchor bolt hole, 7-stiffening steel plate, 8-preset glue injection hole, 9-fixing pin insert, 10-bolt connection hole, 11-steel gasket, 12-chemical anchor bolt, 13-vent hole. Detailed Implementation

[0040] To make the technical problems, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. The specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Specific details, such as particular system structures and technologies, are provided to facilitate a more thorough understanding of the embodiments of this invention. The described embodiments are only some, not all, of the embodiments disclosed herein. However, those skilled in the art should understand that the invention can be implemented in other embodiments without these specific details. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without inventive effort are within the scope of protection of this disclosure.

[0041] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0042] Taking the renovation of a frame beam as an example, the beam section is 300mm×600mm, and a rectangular opening of 400mm×400mm is opened. The original beam concrete strength is C30.

[0043] 1. Device parameters:

[0044] Prefabricated split steel sleeve assembly: four L-shaped steel plates 1, 10mm thick, and 2 raised ribs 5mm high;

[0045] Welded U-shaped hoop plate module: base plate 4, 300mm wide; vertical plate 5, 650mm high; stiffening steel plates 7, 200mm spacing.

[0046] Chemical anchor 12: Φ12mm, anchoring depth 160mm, eight anchors are arranged on each side of the vertical plate 5.

[0047] 2. Device Composition:

[0048] like Figure 2 As shown, the prefabricated split steel sleeve assembly includes four prefabricated L-shaped steel plates 1 (10mm thick). Each L-shaped steel plate 1 has a 5mm high rib 2 machined on its outer side. The rib 2 enhances the mechanical interlocking with the concrete. Fixing pins 9 are provided on both sides of the L-shaped steel plate 1. The fixing pins 9 ensure assembly accuracy and prevent the expansion of cracks in the opening. Bolt connection holes 10 are provided on the fixing pins 9. Figure 3 As shown, four L-shaped steel plates are connected and assembled with bolts 3 through fixing pin inserts 9 to form an annular constraint sleeve. Several steel shims 11 are fitted in the middle of the bolts 3 as needed. The length and width of the steel sleeve are adjusted by these steel shims 11 to meet the needs of different sized openings.

[0049] like Figure 4 As shown, the welded U-shaped hoop module is a U-shaped frame welded from a base plate 4 (300mm wide) and two upright plates 5 (650mm high). Each upright plate 5 has eight anchor bolt holes 6, and chemical anchor bolts 12 with a diameter d of 12mm and an anchoring depth of 160mm are used. Reinforcing steel plates 7 are symmetrically welded to the outer sides of the two upright plates 5.

[0050] like Figure 5 As shown, the concrete beam has a pre-set injection hole 8 and an air vent 13. Modified epoxy resin structural adhesive is injected into the pre-set injection hole 8.

[0051] 3. Construction parameters:

[0052] The load was reduced to 25kN, the gap between the steel sleeve assembly was 1.2mm, and the final bolt tightening torque was 120N·m.

[0053] The injection pressure is 0.25 MPa, and the effective bonding area of ​​the adhesive layer is 96%.

[0054] When the load is restored to 100%, the mid-span strain is 185με and the deflection is 12mm, which meets the specifications.

[0055] 4. Process flow of modular processing method

[0056] Finite element analysis was used to determine the unloading level to 25kN. The unloading was carried out in stages using hydraulic jacks, with each stage lasting 20 minutes. The prefabricated split steel sleeve components and welded U-shaped hoop modules were manufactured in the factory, with a pre-assembly error of 1.2mm.

[0057] Four L-shaped steel plates 1 are embedded into the opening and temporarily fixed by fixing pins 9. Bolts 3 are tightened in diagonal order, with a final tightening torque of 120 N·m, forming a ring-shaped constraint sleeve. Several steel shims 12 are set in the middle as needed.

[0058] The bottom plate 4 is attached to the bottom surface of the beam, and the vertical plate 5 is welded to the bottom plate 4. Reinforcing steel plates 7 are symmetrically welded to the outside of the vertical plate 5 at a spacing of 200mm to form a three-dimensional force system.

[0059] Drill a hole at the position corresponding to anchor bolt hole 6, clean the hole and then insert chemical anchor bolt 12;

[0060] Inject modified epoxy structural adhesive into the lowest preset injection hole 8, control the pressure at 0.25 MPa, until bubble-free adhesive overflows from the vent hole 13. Maintain the pressure for 5 minutes and then seal the channel. The effective bonding area of ​​the adhesive layer is 96%.

[0061] The load was restored to 100% in stages, with each stage lasting for 1 hour. The mid-span strain was 185 με and the deflection was 12 mm. Finally, a 1.2 times overload test was conducted, and the structure showed no abnormalities after 2 hours of holding the load.

[0062] This invention utilizes prefabricated, modular steel sleeve components and welded U-shaped hoop modules for on-site assembly, reinforcement with stiffening steel plates, and chemical anchoring, combined with pressure injection molding, to form a composite load-bearing system. This processing method offers high construction efficiency and reliable load-bearing capacity, making it suitable for reinforcing concrete beams in building renovations and providing significant economic and social benefits.

[0063] The above embodiments are used to explain and illustrate the present invention, and not to limit the invention. Any modifications and changes made to the present invention within the spirit and scope of the claims should be included within the scope of protection of the present invention.

Claims

1. A modular reinforcement device for creating large openings in concrete structural beams, characterized in that: The system includes a prefabricated split steel sleeve assembly and a welded U-shaped clamp module. The prefabricated split steel sleeve assembly includes four L-shaped steel plates (1), each L-shaped steel plate (1) having a rib (2) processed on its outer side. The four L-shaped steel plates (1) are joined together by bolts (3) to form a ring-shaped constraint sleeve. The welded U-shaped clamp module is a U-shaped frame welded from a base plate (4) and two upright plates (5). Anchor bolt holes (6) are opened on the upright plates (5), and stiffening steel plates (7) are symmetrically welded on the outer sides of the two upright plates (5). The concrete structural beam has pre-set glue injection holes (8). The L-shaped steel plate (1) is provided with fixing pin inserts (9) on both sides of the end. The fixing pin inserts (9) have bolt connection holes (10). The four L-shaped steel plates (1) are connected and fixed by bolts (3) through the fixing pin inserts (9). The preload of the bolts (3) is 100-160 N·m. The bolt (3) is fitted with several steel washers (11) in the middle. The length and width of the steel sleeve are adjusted by these steel washers (11) to meet the needs of different sized openings. Modified epoxy resin structural adhesive is injected into the pre-set injection hole (8), with a bonding strength ≥10MPa. It can be cured in an environment above 5℃. The steel sleeve ribs and structural adhesive form a dual force transmission of "mechanical interlocking + bonding".

2. The modular reinforcement device for creating large openings in concrete structural beams according to claim 1, characterized in that, The height of the upright plate (5) is 1.2-1.8 times higher than the height of the opening.

3. The modular reinforcement device for creating large openings in concrete structural beams according to claim 1, characterized in that, The spacing of the anchor bolt holes (6) is 100-150mm. The diameter d of the chemical anchor bolts (12) is 12-18mm, the anchoring depth is ≥10d, and the design value of the pull-out bearing capacity of a single bolt is ≥10kN.

4. A modular reinforcement method for large openings in concrete structural beams, employing the modular reinforcement device for large openings in concrete structural beams as described in any one of claims 1-3, characterized in that, Includes the following steps: The load on the upper part of the beam is removed in stages; Four L-shaped steel plates (1) are embedded into the opening and temporarily fixed by fixing pins (9). The bolts (3) are tightened in diagonal order to form a ring-shaped constraint sleeve. Several steel shims (11) are set in the middle as needed. The bottom plate (4) is attached to the bottom surface of the beam, and the vertical plate (5) is welded to the bottom plate (4). Reinforcing steel plates (7) are symmetrically welded to the outside of the vertical plate (5). Drill holes at the corresponding positions of the anchor bolt holes (6), clean the holes, and then insert chemical anchor bolts (12). Modified epoxy resin structural adhesive is injected from the lowest preset injection hole (8) to form a composite stress system; Graded restoration of the upper load on the beam.

5. A modular reinforcement method for creating large openings in concrete structural beams according to claim 4, characterized in that, The preload of the bolt (3) is 100-160 N·m.

6. A modular reinforcement method for creating large openings in concrete structural beams according to claim 4, characterized in that, The height of the upright plate (5) is 1.2-1.8 times higher than the height of the opening.

7. A modular reinforcement method for creating large openings in concrete structural beams according to claim 4, characterized in that, The chemical anchor (12) has a diameter d of 12-18mm, an anchoring depth ≥10d, and a single anchor pull-out bearing capacity design value ≥10kN.

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