A method for correcting the vertical butt joint accuracy of rectangular steel pipe beams

Abstract

This invention discloses a method for correcting the vertical alignment accuracy of rectangular steel pipe beams, relating to the field of steel structure construction technology. The method includes: after the steel pipe beams are positioned and temporarily fixed, measuring the vertical deviation *h* between the higher and lower beams at the joint; correction is performed when 0 < *h* < the cover plate wall thickness *t*; retaining the cover plate and flange within 500mm on each side of the joint, while temporarily not installing the web plate; processing all joints with a 45° full bevel; welding a Q345, 30mm thick, right-angled counterweight bar to the upper part of the cover plate and flange of the lower beam; using a ≥100T hydraulic jack for graded correction, first correcting the cover plate, then the flange plate; after correction, welding the cover plate and flange plate first, removing the fixtures after cooling, and then welding the web plate. This invention solves the problem of minor vertical misalignment during the jointing of large-span rectangular steel pipe beams, offering high correction accuracy, simple fixtures, low cost, and safe construction, suitable for rapid on-site installation.

Description

Technical Field

[0001] This invention relates to the field of steel structure fabrication and installation technology, and in particular to a method for correcting the vertical connection accuracy of rectangular steel pipe beams. Background Technology

[0002] With the development of building and bridge engineering towards large spans, irregular shapes, and aesthetic appeal, rectangular steel pipe beams are being used more and more widely. Due to the large span of these components, bending deformation is easily generated during processing, transportation, and installation, leading to vertical misalignment when two sections of the steel pipe beam are joined, directly affecting welding quality and structural safety. Existing correction methods mostly employ overall adjustment or large tooling, which suffers from high costs, complex operations, difficulty in controlling correction accuracy, and poor on-site adaptability. Therefore, a simple, efficient, economical, and safe correction method is urgently needed. Summary of the Invention

[0003] This invention aims to overcome the shortcomings of existing technologies and provide a method for correcting the vertical alignment accuracy of rectangular steel pipe beams. By utilizing the characteristics of rectangular steel pipe cross-sections and simple tooling, it can quickly and accurately correct minor vertical misalignments, improve alignment quality and construction efficiency, reduce construction costs, and ensure structural safety.

[0004] To achieve the above objectives, the present invention provides a method for correcting the vertical connection accuracy of rectangular steel pipe beams, comprising the following steps: 1) Deviation verification: After the rectangular steel pipe beams are positioned and temporarily supported and fixed, the vertical deviation h between the higher and lower rectangular steel pipe beams at the connection point is measured; when 0 < h < cover plate wall thickness t is satisfied, the correction process is performed; 2) Section pretreatment: Within 500mm on both sides of the joint, the cover plate and flange are retained, and the web plate is not installed temporarily; all steel plate joints in the connecting section are processed into 45° full bevels; 3) Fabrication and installation of counter-pressure rods: Q345 steel plates are used to fabricate counter-pressure rods with a wall thickness of 30mm; the counter-pressure rods are L-shaped with a bending angle of 90°, a length of 500mm, a height of 500mm, and a width of 100mm at one end. 1) The other end is 200mm wide; the counter-pressure rod is welded to the upper part of the cover plate and flange of the low rectangular steel pipe beam, the counter-pressure rod is aligned with the axis of the steel beam, and the end is 100mm away from the joint; double-sided welding is carried out using CO2 gas shielded welding, and the weld height is 5mm; 4) Graded correction: hydraulic jacks with a rated tonnage ≥100T are used to apply pressure slowly and uniformly; first, the cover plate of the high beam is pressed down until the vertical misalignment of the cover plates at both ends is eliminated; then the flange of the high beam is pressed down until the vertical misalignment of the flanges at both ends is eliminated; the displacement of the jack in a single press is not greater than 2mm; 5) Welding and closing: after the correction is completed, the cover plate and flange are welded first; after the weld cools down, the hydraulic jack and counter-pressure rod are removed; finally, the web plates on both sides are welded to complete the butt joint closure.

[0005] Furthermore, the bend of the right-angled counter-pressure rod is a circular arc transition with a radius R ≥ 15 mm.

[0006] Furthermore, the cover plate and wing plate are welded using multi-layer, multi-pass welding with a welding current of 220–260A and a welding voltage of 28–32V.

[0007] Compared with the prior art, the present invention has the following advantages: 1) High correction accuracy: The graded top pressure method is adopted to specifically eliminate the height difference between the cover plate and the wing plate, which can accurately control small deviations and make the accuracy controllable; 2) Simple construction: The tooling structure is simple and the process is clear. Ordinary welders can operate it, and it is highly adaptable to the site. 3) Low cost: No large equipment is required, the counterweight rod uses conventional steel and the amount used is small, and the tooling can be made on site, reducing construction costs; 4) Safe and reliable: The straightening process is slow and uniform, avoiding plastic deformation of the components, resulting in good welding quality after straightening and improving structural safety; 5) High construction efficiency: It shortens the adjustment and correction time, is suitable for rapid on-site construction, and shortens the construction period. Attached Figure Description

[0008] Figure 1 This is a schematic diagram illustrating the measurement of the vertical deviation h of the rectangular steel pipe beam according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the cover plate wall thickness t according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the cross-sectional structure of a rectangular steel pipe beam according to an embodiment of the present invention; Figure 4 for Figure 3 Enlarged view of the P-section; Figure 5 This is a schematic diagram illustrating the jack correction principle of an embodiment of the present invention; Figure 6 This is a schematic diagram of the counter-pressure rod structure according to an embodiment of the present invention.

[0009] In the figure: 1—low-position rectangular steel pipe beam, 2—high-position rectangular steel pipe beam, 3—cover plate, 4—web plate, 5—wing plate, 6—counter-pressure rod, 7—hydraulic jack; h—vertical deviation, t—cover plate wall thickness. Detailed Implementation

[0010] The present invention will now be described in further detail with reference to the accompanying drawings.

[0011] See Figures 1-6 The present invention provides a method for correcting the vertical butt joint accuracy of rectangular steel pipe beams, comprising the following steps: 1. Deviation verification After the rectangular steel pipe beams are installed and temporarily supported, the vertical deviation h between the high rectangular steel pipe beam 2 and the low rectangular steel pipe beam 1 at the closure point is measured with calipers. When 0 < h < cover plate 3 wall thickness t is satisfied, this method is used for accuracy correction.

[0012] 2. Pretreatment of steel pipe beam section (1) When producing the steel pipe beam connection section, retain the cover plate 3 and the wing plate 5 within 500mm on both sides of the joint, and do not install the web plates 4 on both sides for the time being. (2) All steel plate joints of the connecting section between the low rectangular steel pipe beam 1 and the high rectangular steel pipe beam 2 are all processed into 45° full bevel welding surfaces.

[0013] 3. Fabrication and installation of counterweight bars (1) The counter-pressure rod 6 is made of Q345 steel plate with a wall thickness of 30mm. The counter-pressure rod 6 is L-shaped with a bending angle of 90°. The bending part is rounded and the radius of the rounded part is R≥15mm. The counter-pressure rod is 500mm long and 500mm high, with a width of 100mm at one end and a width of 200mm at the other end. (2) Install the counter-pressure rod 6 on the cover plate 3 and the upper part of the wing plate 5 of the low rectangular steel pipe beam 1. The counter-pressure rod 6 is aligned with the axis of the steel beam, and its end is close to the joint and 100mm away from the joint. (3) The counterweight rod 6 is welded on both sides using CO2 gas shielded welding, with a weld height of 5mm.

[0014] 4. Graded precision correction After the counter-pressure rod 6 is installed, a hydraulic jack 7 with a rated tonnage of ≥100T is used for correction. The correction process is slow and the pressure is applied at a uniform speed. The displacement of the jack in a single press is no more than 2mm. (1) First, apply hydraulic jack 7 to the inner side of the end of the high beam cover plate 3 and apply pressure until the vertical misalignment of the two end cover plates 3 is eliminated; (2) After the cover plate is corrected, the hydraulic jack 7 is applied to the inner side of the end of the high beam flange 5 to apply pressure until the vertical misalignment of the flanges 5 at both ends is eliminated, thus completing the accuracy correction of the cover plate and flange.

[0015] 5. Welding and joining (1) After the correction is completed, first weld the cover plate 3 and the wing plate 5. The welding adopts multi-layer multi-pass welding, the welding current is 220~260A, and the welding voltage is 28~32V. (2) After the cover plate and wing plate welds have cooled naturally, remove the hydraulic jack 7 and the counter-pressure rod 6; (3) Finally, weld the two web plates 4 on both sides to complete the butt joint of the rectangular steel pipe beam.

[0016] This invention has been successfully applied in the Shangli North-South Street Urban Renewal Project, with significant implementation results. The correction accuracy meets the design requirements, and the construction is convenient and efficient, which has been fully affirmed by the implementing unit, the supervision unit, and the construction unit.

[0017] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for correcting the vertical butt joint accuracy of rectangular steel pipe beams, characterized in that, Includes the following steps: Deviation verification: After the rectangular steel pipe beam is in place and temporarily supported and fixed, measure the vertical deviation h between the high rectangular steel pipe beam and the low rectangular steel pipe beam at the joint; when 0 < h < cover plate wall thickness t is satisfied, the correction procedure is performed. 2) Section pretreatment: Within 500mm on both sides of the joint, retain the cover plate and wing plate, and do not install the web plate for the time being; all steel plate joints in the connecting section are processed into 45° full bevels; 3) Fabrication and installation of counterweight rods: Counterweight rods are fabricated using Q345 steel plates with a wall thickness of 30mm. The counterweight rods are L-shaped with a bending angle of 90°, 500mm long and 500mm high, with a width of 100mm at one end and 200mm at the other. The counterweight rods are welded to the upper part of the cover plate and flange of the low-position rectangular steel pipe beam, with the counterweight rods aligned with the axis of the steel beam and the end 100mm from the joint. Double-sided welding is performed using CO2 gas shielded welding, with a weld height of 5mm. 4) Graded correction: Use hydraulic jacks with a rated tonnage ≥100T to apply pressure slowly and at a uniform speed; first press the high beam cover plate until the vertical misalignment of the cover plates at both ends is eliminated; then press the high beam flange plate until the vertical misalignment of the flange plates at both ends is eliminated; the displacement of the jack in a single press should not exceed 2mm. 5) Welding and joining: After the correction is completed, first weld the cover plate and the wing plate; after the weld has cooled, remove the hydraulic jack and the counter-pressure rod; finally, weld the two side web plates to complete the joining and joining.

2. The method for correcting the vertical butt joint accuracy of rectangular steel pipe beams according to claim 1, characterized in that: The bend of the right-angled counterweight rod is a circular arc transition with a radius R ≥ 15 mm.

3. The method for correcting the vertical butt joint accuracy of rectangular steel pipe beams according to claim 1, characterized in that: The cover plate and wing plate are welded using multi-layer, multi-pass welding with a welding current of 220–260A and a welding voltage of 28–32V.

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