A method for precise matching and positioning of cantilevered steel box girders in all weather conditions

Abstract

This invention discloses an all-weather method for precise matching and positioning of suspended steel box girders, comprising: Step S1, calculating the actual displacement of the completed bridge and setting a pre-camber during steel beam fabrication, i.e., manufacturing pre-camber; Step S2, setting matching parts between splices during long-line matching prefabrication in the factory, and positioning the steel beams according to the matching parts during on-site assembly to achieve preliminary positioning of the steel beams and perform rough matching of beam segments; Step S3, calculating the precise elevation of the steel beams based on the existing steel beam positions and the relative positional relationship between beam segments according to the manufacturing line, and performing fine matching of beam segments; Step S4, calculating the assembly elevation in real time based on real-time measurement data during fine matching, adjusting and locking the elevation, and promptly re-measuring and correcting; Step S5, after adjustment, welding the support plate to fix the relative position of the structure. This method enables precise matching construction of steel box girders under conditions of drastic daytime environmental changes, greatly saving construction time.

Description

Technical Field

[0001] This invention relates to an all-weather method for precise matching and positioning of suspended steel box girders. Background Technology

[0002] The cantilever assembly control of steel beams constructed using welding technology follows the principle of tangent method assembly. That is, after the steel beam is hoisted into place, it is roughly matched using matching parts to basically restore its original shape during manufacturing. Then, through measurement, calculation and analysis, the end elevation of the beam is adjusted to achieve fine matching and complete the accurate positioning of the steel beam.

[0003] However, since temperature and sunlight have a significant impact on the alignment of the main beam, the traditional construction control method for steel beam assembly is to measure and precisely match the temperature during the nighttime period, which results in low construction efficiency.

[0004] Therefore, an all-weather method for precise matching and positioning of steel box girder cantilever splicing is provided. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing methods and provide an all-weather steel box girder cantilever splicing precision matching and positioning method, which realizes the precision matching construction of steel box girders under the condition of drastic daytime environmental changes, and greatly saves the construction period.

[0006] The technical solution to achieve the above objectives is:

[0007] A method for precise matching and positioning of suspended steel box girders under all weather conditions, comprising:

[0008] Step S1: When processing the steel beams, calculate the actual displacement of the completed bridge and set the pre-camber, i.e., manufacture the pre-camber;

[0009] Step S2: During the long-line matching prefabrication process in the factory, the matching parts between the joints are set up. During on-site assembly, the steel beams are positioned according to the matching parts to achieve the initial positioning of the steel beams and to perform rough matching of the beam segments.

[0010] Step S3: Based on the existing steel beam positions and the relative positional relationships between beam segments in the manufacturing line, calculate the precise elevation of the steel beams and perform precise matching of beam segments;

[0011] Step S4: At the precise matching moment, calculations are performed using real-time measurement data to promptly calculate the assembly elevation, adjust and lock the elevation, and promptly re-measure and correct.

[0012] Step S5: After adjustment, weld the support plate to fix the relative position of the structure;

[0013] Step S6: After welding is completed, the elevation is re-measured and errors are corrected. Steps S3-S5 are repeated to adjust the steel box girder until it meets the steel box girder precision matching construction standards, thereby completing the steel box girder cantilever assembly.

[0014] Preferably, in step S1, the pre-camber is equal to the actual structural displacement, which is the actual structural displacement calculated according to the tangent method during the last working condition.

[0015] Preferably, in step S3, the manufacturing profile can be calculated using finite element software, where the manufacturing profile = design profile + manufacturing pre-camber, and the design profile is determined by the construction personnel.

[0016] Preferably, in step S3, the installed segments are measured before fine matching, and the accurate position of the segment to be installed is calculated based on the relative position of the manufacturing line.

[0017] Let the lengths of the installed beam segments be L1 and L2, and the length of the beam segment to be installed be L3;

[0018] In the manufacturing line, the elevations of beam segments L1 and L2 that have been installed are y1 and y2 respectively, and the elevation of beam segment L3 that is to be installed is y3.

[0019] During on-site assembly, the elevations of the installed beam segments L1 and L2 are y'1, y'2, and y'3, respectively, while the elevation of the beam segment L3 to be installed is y'3.

[0020] Therefore, based on geometric knowledge, the elevation y'3 of beam segment L3 in the on-site assembly section can be calculated from the manufacturing alignment:

[0021]

[0022] y′3=y′1+L 12 sin(θ3+θ2-θ1);

[0023]

[0024] In the formula, θ1 is the angle between the installed beam segment L1 in the manufacturing alignment and the horizontal plane, θ2 is the angle between the installed beam segment L1 in the field assembly and the horizontal plane, θ3 is the angle between the connecting line of the first end of the installed beam segment L1 and the last end of the installed beam segment L2 in the manufacturing alignment and the horizontal plane, and α is the angle between the installed beam segments L1 and L2.

[0025] Since α→180° and cosα→-1, then L 12 ≈L1+L2, that is:

[0026] y′3=y′1+(L1+L2)sin(θ3+θ2-θ1).

[0027] Preferably, the errors in step S4 include: process errors and sequential assembly errors;

[0028] Process error:

[0029] The elevations y1, y2, and y3 of beam segments L1, L2, and L3 before welding, after precision matching, should theoretically have the same spatial relative relationship as the elevations y'1, y'2, and y'3 of beam segments L1, L2, and L3 after welding. However, due to errors caused by welding deformation and construction processes, their spatial orientation changes. The formula for calculating the process error is:

[0030] Δy=y′3-[y′1+L 12 sin(θ3+θ2-θ1)];

[0031] Sequential stitching error:

[0032] The alignment error is the deviation between the segment elevation and the manufacturing alignment when assembling according to the tangent method. Considering only the error of adjacent steel beam segments, the errors of the installed beam segments L1 and L2 are Δx1 and Δx2, respectively. Then, the error Δx3 of the beam segment to be installed, L3, is:

[0033]

[0034] Then, based on Δy obtained from the process error and Δx3 obtained from the sequential assembly error, the elevation is adjusted and locked, and timely retesting and correction are carried out.

[0035] The beneficial effects of this invention are as follows: Based on the fact that the theoretical spatial relative position of the steel beam is fixed, although the actual measured elevation of the steel beam is constantly changing due to environmental influences, as long as the assembly elevation is calculated in real time based on the measurement data at the precise matching moment, and the elevation is adjusted and locked, and timely re-measurement and correction are carried out, the purpose of precise matching construction of steel box girder can be achieved at any time. Attached Figure Description

[0036] Figure 1 This is a flowchart of an all-weather steel box girder cantilever splicing precision matching and positioning method according to the present invention;

[0037] Figure 2 This is a schematic diagram of the installation of the linear beam segment in this invention;

[0038] Figure 3 This is a schematic diagram of a beam segment with pre-installed linear sections manufactured in this invention;

[0039] Figure 4 This is a schematic diagram of the beam segment assembled on-site in this invention;

[0040] Figure 5 This is a schematic diagram of beam segment installation caused by sequential splicing errors in this invention. Detailed Implementation

[0041] The technical solution of the present invention will now be clearly and completely described in conjunction with the accompanying drawings. In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0042] The invention will now be further described with reference to the accompanying drawings.

[0043] The process of assembling and splicing steel box girders for cable-stayed bridges includes steel beam lifting, rough matching, fine matching, and welding.

[0044] (1) Steel beam lifting

[0045] a) Use two steel strand jacks on the bridge deck crane to lower the two bridge deck spreader beams to the upper part of the steel box girder segment, with an error not exceeding ±1m of the specified position, so that the steel strand jacks can be released.

[0046] b) Connect the crane lifting beam to the lifting lugs of the steel box girder using wire rope slings.

[0047] Use a hydraulic pump to adjust the position of the spreader beam slide plate to be directly above the theoretical center of gravity of the predetermined bridge deck segment.

[0048] c) Lock the spreader beam slide plate with a threaded rod system.

[0049] d) Use the two longitudinal adjustment cylinders on the lifting system to push the jack frame to the predetermined position, open the jacks, and lift the steel beam into place.

[0050] (2) Coarse matching of beam segments

[0051] a) When the beam segment is hoisted to near the bridge deck, use the horizontal jacks on the hoisting equipment to adjust the longitudinal slope of the hoisted steel box girder to be consistent with the longitudinal slope of the already installed beam segment, so that the gap width of the upper and lower interfaces at the corresponding positions of the already installed beam segment is approximately equal. Continue to lift the beam segment and adjust the elevation so that it is roughly flush with the surface of the already installed beam segment.

[0052] b) Use the longitudinal adjustment jacks at the front of the bridge crane to drive the steel box girder longitudinally, so that the girder segment slowly moves closer to the already installed girder segment. Then, use the lateral adjustment jacks at the front of the bridge crane to adjust the lateral position of the steel box girder, so that the axis of the hoisted girder segment is aligned with the axis of the already installed girder segment.

[0053] c) Make repeated fine adjustments to align the top stop plate at the longitudinal diaphragm of the hoisted beam segment with that of the already installed beam segment.

[0054] d) Weld cross-limiting plates onto the top plate to restrict displacement of adjacent beam segments, and connect the matching parts at the longitudinal diaphragm of the beam segments with bolts to lock the main lifting jack. At this point, the rough matching of the beam segments is complete.

[0055] (3) Precision matching of beam segments

[0056] According to the control elevation in the monitoring instructions, the hydraulic jacks of the bridge deck crane are activated to make fine adjustments to the steel beam elevation to achieve the commanded elevation; at the same time, the jacks are used to correct the deviation of the steel beam axis.

[0057] After the above adjustments are completed, weld the mounting plate to fix the relative position of the structure.

[0058] This invention calculates the elevation pre-control based on the geometric control method of the manufacturing line during the coarse matching and fine matching stages of the beam segments, thereby completing the cantilever assembly of the steel box girder.

[0059] like Figure 1 As shown, an all-weather steel box girder cantilever splicing precision matching and positioning method includes:

[0060] Step S1: When processing the steel beams, calculate the actual displacement of the completed bridge and set the pre-camber, i.e., manufacture the pre-camber.

[0061] In the embodiment, the pre-camber is equal to the actual structural displacement, which is the actual displacement of the structure under the last working condition calculated according to the tangent method.

[0062] Step S2: During the long-line matching prefabrication process in the factory, matching parts are set between the joints. During on-site assembly, the steel beams are positioned according to the matching parts to achieve preliminary positioning and rough matching of beam segments.

[0063] Step S3: Calculate the precise elevation of the steel beams based on the existing steel beam positions and the relative positional relationships between beam segments in the manufacturing line, and perform precise matching of beam segments.

[0064] In this embodiment, the manufacturing profile can be calculated using finite element software. The manufacturing profile = design profile + manufacturing pre-camber. The design profile is designed by the construction personnel.

[0065] In this embodiment, the installed segments are measured before fine matching, and the accurate position of the segment to be installed is calculated based on the relative position of the manufacturing line.

[0066] like Figure 2-4 As shown, the lengths of the beam segments that have been installed are L1 and L2, and the length of the beam segment to be installed is L3.

[0067] In the manufacturing line, the elevations of beam segments L1 and L2 that have been installed are y1 and y2, respectively, and the elevation of beam segment L3 that is to be installed is y3.

[0068] During on-site assembly, the elevations of the installed beam segments L1 and L2 are y'1, y'2, and y'3, respectively, while the elevation of the beam segment L3 to be installed is y'3.

[0069] Therefore, based on geometric knowledge, the elevation y'3 of beam segment L3 in the on-site assembly section can be calculated from the manufacturing alignment:

[0070]

[0071] y′3=y′1+L 12 sin(θ3+θ2-θ1);

[0072]

[0073] In the formula, θ1 is the angle between the installed beam segment L1 in the manufacturing alignment and the horizontal plane, θ2 is the angle between the installed beam segment L1 in the field assembly and the horizontal plane, θ3 is the angle between the connecting line of the first end of the installed beam segment L1 and the last end of the installed beam segment L2 in the manufacturing alignment and the horizontal plane, and α is the angle between the installed beam segments L1 and L2.

[0074] Since α→180° and cosα→-1, then L 12 ≈L1+L2, that is:

[0075] y′3=y′1+(L1+L2)sin(θ3+θ2-θ1).

[0076] Step S4: At the precise matching moment, calculations are performed using real-time measurement data to calculate the assembly elevation in a timely manner, and the elevation is adjusted and locked, and timely re-measurement and correction are carried out.

[0077] In this embodiment, the errors in step S4 include: process errors and sequential assembly errors;

[0078] Process error:

[0079] The elevations y1, y2, and y3 of beam segments L1, L2, and L3 before welding, after precision matching, should theoretically have the same spatial relative relationship as the elevations y'1, y'2, and y'3 of beam segments L1, L2, and L3 after welding. However, due to errors caused by welding deformation and construction processes, their spatial orientation changes. The formula for calculating the process error is:

[0080] Δy=y′3-[y′1+L 12 sin(θ3+θ2-θ1)];

[0081] Sequential stitching error:

[0082] The error in sequential assembly refers to the deviation between the elevation of a segment and its manufacturing alignment during tangent-based assembly. It only considers the error between adjacent steel beam segments. Assembled beam segments, having already been stressed, have deviated from their manufacturing alignment and cannot be used as a basis for judgment. Figure 5 As shown, based on the measurements, the errors of the installed beam segments L1 and L2 are Δx1 and Δx2, respectively. Therefore, the error Δx3 of the beam segment L3 to be installed is:

[0083]

[0084] Then, based on Δy obtained from the process error and Δx3 obtained from the sequential assembly error, the elevation is adjusted and locked, and timely retesting and correction are carried out.

[0085] In this embodiment, the error should also consider cross-sectional deformation. During cross-sectional elevation measurement, the cross-section will deform laterally due to the structure being under stress, and this should be taken into account when evaluating the structural alignment. For example, during the hoisting of the steel box girder of a cable-stayed bridge, the elevation of the hoisting point will be slightly higher. After the stay cables are tensioned, the elevation of the top surface of the steel beam at the stay cable anchorage point will also be slightly higher. The amount of lateral deformation of the cross-section should be calculated before construction and measured during construction to adjust the elevation. Data with significant deviations should be discarded.

[0086] Step S5: After adjustment, weld the mounting plate to fix the relative position of the structure.

[0087] Step S6: After welding is completed, the elevation is re-measured and errors are corrected. Steps S3-S5 are repeated to adjust the steel box girder until it meets the steel box girder precision matching construction standards, thus completing the steel box girder cantilever assembly.

[0088] 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 the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for all-weather precision matching and positioning of suspended steel box girders, characterized in that, include: Step S1: When processing the steel beams, calculate the actual displacement of the completed bridge and set the pre-camber, i.e., manufacture the pre-camber; Step S2: During the long-line matching prefabrication process in the factory, the matching parts between the joints are set up. During on-site assembly, the steel beams are positioned according to the matching parts to achieve the initial positioning of the steel beams and to perform rough matching of the beam segments. Step S3: Based on the existing steel beam positions and the relative positional relationships between beam segments in the manufacturing line, calculate the precise elevation of the steel beams and perform precise matching of beam segments; Step S4: At the precise matching moment, calculations are performed using real-time measurement data to promptly calculate the assembly elevation, adjust and lock the elevation, and promptly re-measure and correct errors. Step S5: After adjustment, weld the support plate to fix the relative position of the structure; Step S6: After welding is completed, the elevation is re-measured and errors are corrected. Steps S3-S5 are repeated to adjust the steel box girder until it meets the steel box girder precision matching construction standards, thereby completing the steel box girder cantilever assembly. In step S1, the pre-camber is equal to the actual structural displacement, which is the actual structural displacement calculated according to the tangent method during the last working condition. In step S3, the manufacturing profile can be calculated using finite element software. Manufacturing profile = design profile + manufacturing pre-camber. The design profile is designed by the construction personnel. In step S3, the installed segments are measured before fine matching, and the accurate position of the segment to be installed is calculated based on the relative position of the manufacturing line. Let the lengths of the installed beam segments be L1 and L2, and the length of the beam segment to be installed be L3; In the manufacturing line, the elevations of beam segments L1 and L2 that have been installed are y1 and y2 respectively, and the elevation of beam segment L3 that is to be installed is y3. During on-site assembly, the elevations of the installed beam segments L1 and L2 are y′1, y′2, and y′3, respectively, while the elevation of the beam segment L3 to be installed is y′3. Therefore, based on geometric knowledge, the elevation y′3 of beam segment L3 in the on-site assembly section can be calculated from the manufacturing alignment: y′3=y′1+L 12 sin(θ3+θ2-θ1); In the formula, θ1 is the angle between the installed beam segment L1 in the manufacturing alignment and the horizontal plane, θ2 is the angle between the installed beam segment L1 in the field assembly and the horizontal plane, θ3 is the angle between the connecting line of the first end of the installed beam segment L1 and the last end of the installed beam segment L2 in the manufacturing alignment and the horizontal plane, and α is the angle between the installed beam segments L1 and L2. Since α→180° and cosα→-1, then L 12 ≈L1+L2, that is: y′3=y′1+(L1+L2)sin(θ3+θ2-θ1); The errors in step S4 include: process errors and sequential assembly errors; Process error: The elevations y1, y2, and y3 of beam segments L1, L2, and L3 before welding, after precision matching, should theoretically have the same spatial relative relationship as the elevations y′1, y′2, and y′3 of beam segments L1, L2, and L3 after welding. However, due to errors caused by welding deformation and construction processes, their spatial orientation changes. The formula for calculating the process error is: Δy=y′3-[y′1+L 12 sin(θ3+θ2-θ1)]; Sequential stitching error: The alignment error is the deviation between the segment elevation and the manufacturing alignment when assembling according to the tangent method. Considering only the error of adjacent steel beam segments, the errors of the installed beam segments L1 and L2 are Δx1 and Δx2, respectively. Then, the error Δx3 of the beam segment to be installed, L3, is: Then, based on Δy obtained from the process error and Δx3 obtained from the sequential assembly error, the elevation is adjusted and locked, and timely retesting and correction are carried out.

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