Method for assembling steel structure box girder with reduced residual stress and installation equipment

Abstract

The application discloses a kind of steel structure box girder assembly construction methods and installation equipment for reducing residual stress, by first section to be assembled segment hoisting and placing in temporary two-ply jig, and adjusting first section to be assembled segment to make its central axis overlap reference axis, second section to be assembled segment hoisting and placing in temporary two-ply jig, and adjusting second section to be assembled segment to make its central axis overlap reference axis, welding connection construction is carried out to the connecting position between first section to be assembled segment and second section to be assembled segment, so that first section and second section are connected to form integral structure, integral structure is hoisted and installed in preset construction area, and the step of hoisting and placing first section to be assembled segment in temporary two-ply jig and adjusting first section to be assembled segment to make its central axis overlap reference axis is repeatedly executed until the installation construction of all integral structures in preset construction area is completed, steel box girder is formed, and construction efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of bridge construction technology, and in particular to a method and equipment for assembling and installing steel box girders to reduce residual stress. Background Technology

[0002] Steel box girders, also known as steel plate box girders, are a common structural form for long-span bridges. They are generally used on bridges with large spans and are called steel box girders because their shape resembles a box. A steel box girder is typically constructed by welding together a top plate, bottom plate, web, transverse diaphragms, longitudinal diaphragms, and stiffening ribs. The top plate is an orthotropic bridge deck composed of a cover plate and longitudinal stiffening ribs.

[0003] In existing technologies, when constructing steel box girders, beam segments are usually assembled on the ground. After assembly, the completed beam segments are then pushed to the construction area using the jacking method to complete the assembly of the steel box girder. Although this method can complete the manufacturing and construction of steel box girders, it has the drawbacks of low construction efficiency, long construction period, and inability to control the axial accuracy of the steel box girder. Summary of the Invention

[0004] The main objective of this invention is to provide a method for assembling and constructing steel box girders to reduce residual stress, thereby solving the technical problems of low construction efficiency, long construction period, and inability to control the axial accuracy of steel box girders in related technologies.

[0005] To achieve the above objectives, in a first aspect, the present invention proposes a method for assembling and constructing steel box girders to reduce residual stress, comprising the following steps: Several segments to be assembled and a temporary two-piece assembly frame are prepared at a pre-designated material preparation site; wherein, a reference axis is provided on the temporary two-piece assembly frame along its extension direction; The first section to be assembled is hoisted and placed on the temporary two-piece assembly frame, and the first section to be assembled is adjusted so that its central axis overlaps with the reference axis; The second section to be assembled is hoisted and placed on the temporary two-piece assembly frame, and the second section to be assembled is adjusted so that its central axis overlaps with the reference axis; wherein the second section to be assembled is adjacent to the first section to be assembled. Welding is performed at the connection points between the first segment to be assembled and the second segment to be assembled, so that the first segment and the second segment are connected to form an integral structure; The overall structure is hoisted and installed in the preset construction area, and the steps of hoisting and placing the first section to be assembled on the temporary two-piece assembly frame and adjusting the first section to be assembled so that its central axis overlaps with the reference axis are repeated until the installation of all the overall structures in the preset construction area is completed, forming the steel box girder.

[0006] Optionally, after the step of preparing several segments to be assembled and a temporary two-piece assembly frame at the pre-designated material preparation site, the method further includes: Several detection points are set on each of the segments to be assembled; wherein the detection points are distributed at intervals along the length extension direction, width extension direction, height extension direction, side bend position, and preset arch bend position of the segment to be assembled.

[0007] Optionally, after the steps of hoisting and placing the first section to be assembled onto the temporary two-piece assembly frame, and adjusting the first section to be assembled so that its central axis overlaps with the reference axis, the method further includes: The detection points are inspected to obtain the detection parameters of the first segment to be assembled; wherein, the detection parameters include the length, width, height, lateral curvature, and preset arch angle of the first segment to be assembled.

[0008] Optionally, the step of welding the connection between the first segment to be assembled and the second segment to be assembled, so that the first segment and the second segment are connected to form an integral structure, includes: A code plate is set at the connection position between the first section to be assembled and the second section to be assembled, so as to adjust the misalignment between the first section to be assembled and the second section to be assembled through the code plate; Welding is performed at the connection points to connect the first segment and the second segment to form an integral structure.

[0009] Optionally, the step of setting a code plate at the connection position between the first segment to be assembled and the second segment to be assembled, so as to adjust the misalignment between the first segment to be assembled and the second segment to be assembled through the code plate, includes: A code plate is set at the connection position between the first section to be assembled and the second section to be assembled, so as to adjust the misalignment between the bottom web plate of the first section to be assembled and the bottom web plate of the second section to be assembled; wherein, the misalignment is A, and A≤0.5mm.

[0010] Optionally, the step of welding the connection at the connection position to connect the first segment and the second segment to form an integral structure includes: Welding is performed at the connection points to connect the first segment and the second segment to form the current segment; The current segment is inspected and polished to obtain the overall structure.

[0011] Optionally, the step of performing inspection and grinding operations on the current segment to obtain the overall structure includes: Perform flaw detection on the current segment; After the flaw detection operation is completed, the current segment is ground to obtain the overall structure.

[0012] Optionally, the step of grinding the current segment after the flaw detection operation to obtain the overall structure includes: After the flaw detection operation is completed, the arc-starting plates at each weld position of the current segment are flame-cut and ground, and the flatness of the weld position is adjusted to B to obtain the overall structure; wherein, B≤1mm / m.

[0013] Optionally, the step of performing flame cutting and grinding operations on the arc-starting plates at each weld position of the current segment after the flaw detection operation is completed, and adjusting the flatness of the weld position to B to obtain the overall structure, includes: After the flaw detection operation is completed, the arc-starting plates at each weld position of the current segment are flame-cut and ground, and the flatness of the weld position is adjusted to B. After the flatness adjustment is completed, each of the welds is touched up with paint to obtain the overall structure.

[0014] Based on the same technical concept, in a second aspect, the present invention proposes an installation device for steel box girders, which is used to perform the steel box girder assembly construction method for reducing residual stress as described in the first aspect.

[0015] The technical solution of this invention involves preparing several assembly segments and a temporary two-section assembly frame at a pre-designated material preparation site. The first assembly segment is hoisted and placed on the temporary two-section assembly frame, and adjusted so that its central axis overlaps with a reference axis. The second assembly segment is then hoisted and placed on the temporary two-section assembly frame, and adjusted so that its central axis overlaps with the reference axis. Welding is then performed at the connection points between the first and second assembly segments to form a unified structure. This unified structure is then hoisted and installed in a pre-designated construction area. The process of hoisting and placing the first assembly segment on the temporary two-section assembly frame and adjusting is repeated. The process involves assembling the first segment to be assembled until its central axis overlaps with the reference axis, until all the overall structures are installed in the pre-designed construction area to form a steel box girder. This allows the invention to control and adjust the central axis between the first and second segments to be installed, which are mounted on temporary two-piece assembly frames, using the set reference axis. Simultaneously, by utilizing the temporary two-piece assembly frames for assembling and welding the first and second segments, the invention eliminates the need for jacking during the assembly of the steel box girder, effectively improving construction efficiency and reducing the construction cycle. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating a method for assembling and constructing steel box girders to reduce residual stress, as exemplified by the present invention. Figure 2 for Figure 1 The flowchart of step S400 in the example is shown; Figure 3 for Figure 2 The flowchart of step S420 in the example is shown; Figure 4 for Figure 3 The flowchart of step S422 in the example is shown; Figure 5 The flowcharts are for some specific embodiments of the present invention.

[0018] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of the mechanisms in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0021] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0022] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0023] The inventive concept of the present invention will be further explained below with reference to some specific embodiments.

[0024] This invention proposes a method and installation equipment for assembling steel box girders to reduce residual stress.

[0025] like Figures 1 to 5 As shown, this invention discloses an embodiment of a method for assembling and constructing steel box girders to reduce residual stress.

[0026] In this embodiment, please refer to Figures 1-5 The method for assembling and constructing steel box girders to reduce residual stress includes the following steps: S100. Prepare several segments to be assembled and a temporary two-piece assembly frame at a pre-designated material preparation site; wherein, the temporary two-piece assembly frame is provided with a reference axis arranged along its extension direction. In this embodiment, when preparing the temporary two-piece jig, the temporary two-piece jig should be configured as a structure that can extend and retract along the extension direction of the temporary two-piece jig. By configuring the temporary two-piece jig as a structure that can extend and retract along the extension direction, the present invention can adjust the extension length of the temporary two-piece jig according to the length of the segment to be assembled during use, so as to realize the splicing function of the overall structure of different lengths.

[0027] S200. Hoist the first section to be assembled onto the temporary two-piece assembly frame and adjust the first section to be assembled so that its central axis overlaps with the reference axis. In this embodiment, when the first segment to be assembled is hoisted and placed on the temporary two-piece assembly frame, the positioning function on the temporary two-piece assembly frame can be used to adjust and control the central axis of the first segment to be assembled, thereby enabling precise control of the assembly accuracy of the steel box girder during use.

[0028] S300. The second section to be assembled is hoisted and placed on the temporary two-piece assembly frame, and the second section to be assembled is adjusted so that its central axis overlaps with the reference axis; wherein the second section to be assembled is adjacent to the first section to be assembled. In this embodiment, when the second section to be assembled is hoisted and placed on the temporary two-section assembly frame, the positioning function on the temporary two-section assembly frame can be used to adjust and control the central axis of the second section to be assembled and the first section to be assembled. This enables precise control of the assembly accuracy of the steel box girder during use, thereby improving the assembly accuracy of the steel box girder.

[0029] S400. Welding is performed at the connection points between the first section to be assembled and the second section to be assembled, so that the first section and the second section are connected to form an integral structure. S500. The overall structure is hoisted and installed in the preset construction area, and the steps of hoisting and placing the first section to be assembled on the temporary two-piece assembly frame and adjusting the first section to be assembled so that its central axis overlaps with the reference axis are repeated until the installation of all the overall structures in the preset construction area is completed, forming the steel box girder.

[0030] To further clarify, when performing welding operations, the welding edges can be numbered, and then the skip welding method can be used, or the entire steel plate can be preheated, electrically heated, to 70-80℃ to reduce residual stress.

[0031] In this embodiment, several segments to be assembled and a temporary two-piece assembly frame are prepared at a pre-designated material preparation site. The first segment to be assembled is hoisted and placed on the temporary two-piece assembly frame, and adjusted so that its central axis overlaps with the reference axis. The second segment to be assembled is hoisted and placed on the temporary two-piece assembly frame, and adjusted so that its central axis overlaps with the reference axis. Welding is then performed at the connection points between the first and second segments to be assembled, so that the first and second segments are connected to form an integral structure. The integral structure is hoisted and installed in the pre-designated construction area, and the process of hoisting and placing the first segment to be assembled on the temporary two-piece assembly frame and adjusting is repeated. The process involves assembling the first segment to be assembled until its central axis overlaps with the reference axis, until all the overall structures are installed in the pre-designed construction area to form a steel box girder. This allows the invention to control and adjust the central axis between the first and second segments to be installed, which are mounted on temporary two-piece assembly frames, using the set reference axis. Simultaneously, by utilizing the temporary two-piece assembly frames for assembling and welding the first and second segments, the invention eliminates the need for jacking during the assembly of the steel box girder, effectively improving construction efficiency and reducing the construction cycle.

[0032] In some specific embodiments, after the step of preparing several segments to be assembled and a temporary two-piece assembly frame at a pre-designated material preparation site, the method further includes: S600. A number of detection points are set on each of the segments to be assembled; wherein the detection points are distributed at intervals along the length extension direction, width extension direction, height extension direction, side bend position, and preset arch bend position of the segments to be assembled.

[0033] In some specific embodiments, after the steps of hoisting and placing the first section to be assembled onto the temporary two-piece assembly frame, and adjusting the first section to be assembled so that its central axis overlaps with the reference axis, the method further includes: S700. Perform testing operations on each of the aforementioned testing points to obtain the testing parameters of the first segment to be assembled; wherein, the testing parameters include the length, width, height, lateral bending, and preset arch angle parameters of the first segment to be assembled.

[0034] In some specific embodiments, the step of welding the connection between the first segment to be assembled and the second segment to be assembled, so as to connect the first segment and the second segment to form an integral structure, includes: S410. Set a code plate at the connection position between the first section to be assembled and the second section to be assembled, so as to adjust the misalignment between the first section to be assembled and the second section to be assembled through the code plate; S420. Welding is performed at the connection points to connect the first segment and the second segment to form an integral structure.

[0035] Optionally, the step of setting a code plate at the connection position between the first segment to be assembled and the second segment to be assembled, so as to adjust the misalignment between the first segment to be assembled and the second segment to be assembled through the code plate, includes: A code plate is set at the connection position between the first section to be assembled and the second section to be assembled, so as to adjust the misalignment between the bottom web plate of the first section to be assembled and the bottom web plate of the second section to be assembled; wherein, the misalignment is A, and A≤0.5mm.

[0036] In this embodiment, the interfaces of the bottom plate, web plate and top plate segments are fixed with a clamping plate to ensure that the misalignment of the top and bottom web plates is ≤0.5mm (t≥25mm,≤1mm). Attention should be paid to the overall dimensions, pre-camber and straightness of the steel box girder.

[0037] In some specific embodiments, the step of welding the connection at the connection location to connect the first segment and the second segment to form an integral structure includes: S421. Perform welding connection construction at the connection position to connect the first segment and the second segment to form the current segment; S422. Perform inspection and polishing operations on the current segment to obtain the overall structure.

[0038] In some specific embodiments, the step of performing inspection and polishing operations on the current segment to obtain the overall structure includes: S422a. Perform flaw detection on the current segment; S422b. After the flaw detection operation is completed, the current segment is ground to obtain the overall structure.

[0039] In some specific embodiments, the step of grinding the current segment after the flaw detection operation to obtain the overall structure includes: After the flaw detection operation is completed, the arc-starting plates at each weld position of the current segment are flame-cut and ground, and the flatness of the weld position is adjusted to B to obtain the overall structure; wherein, B≤1mm / m.

[0040] In some specific embodiments, the step of performing flame cutting and grinding operations on the arc-starting plates at each weld position of the current segment after the completion of flaw detection, and adjusting the flatness of the weld position to B to obtain the overall structure includes: After the flaw detection operation is completed, the arc-starting plates at each weld position of the current segment are flame-cut and ground, and the flatness of the weld position is adjusted to B. After the flatness adjustment is completed, each of the welds is touched up with paint to obtain the overall structure.

[0041] Of course, in actual use, when assembling the steel box girder, it is also necessary to install the crossbeams and steel bottom formwork within the steel box girder. Specifically, the crossbeam is an I-beam structure, consisting of an upper cover plate, a lower cover plate, a web plate, and stiffeners. The top plate of the crossbeam is welded to the upper flange plate of the steel box girder, while the bottom plate and web of the crossbeam are bolted to the bottom plate and web of the steel box girder.

[0042] In each steel box girder segment, when installing the longitudinal crossbeams, the crossbeams at both ends of the steel box girder should be installed first, followed by the other crossbeams. When installing the transverse crossbeams, the principle is to install them from the inside to the outside, i.e. from the high-speed side to the non-high-speed side.

[0043] The specific installation process for the crossbeams is as follows.

[0044] Before hoisting, understand the installation position of each component beam and the connection method between the steel box girder and the beam.

[0045] When hoisting crossbeams, it is strictly forbidden for anyone to stand within the swing radius of the crane boom.

[0046] Install the crossbeam with the center line of the web of the crossbeam joint on the steel box girder as the reference, ensuring that the center line of the web of the crossbeam is flush with the center line of the web of the crossbeam joint on the steel box girder, and control the misalignment of the top plate, bottom plate, and web to ≤0.5mm.

[0047] Use a mounting plate to fix the interface between the upper flange of the steel box girder and the upper cover plate of the crossbeam.

[0048] High-strength bolts are used to connect the web of the crossbeam to the web of the crossbeam joint of the steel box girder, and the bottom plate of the crossbeam to the bottom plate of the crossbeam joint of the steel box girder. During construction, it is necessary to correctly distinguish the splicing plates of the bottom plates of crossbeams with different thicknesses. The torque wrench must be calibrated in advance by a qualified testing unit.

[0049] Weld the upper cover plate of the crossbeam to the upper flange plate of the steel box girder according to the welding process requirements, and grind the weld.

[0050] The butt welds were subjected to flaw detection according to the flaw detection requirements.

[0051] The welded areas were repainted according to the painting process, and the damaged paint on the crossbeams was also repaired.

[0052] The fourth span of a certain bridge consists of 259 steel bottom formwork pieces. According to the construction process, the steel bottom formwork is installed longitudinally from the large segment to the small segment, that is, the 17 steel bottom formwork segments are installed first, and the 1st steel bottom formwork segment is installed last.

[0053] The fourth steel bottom formwork is lapped on the flange of the top plate of the steel box girder and the upper flange of the crossbeam, and is connected by full fillet weld.

[0054] Before hoisting, understand the installation location of each steel bottom formwork component and the connection method between the steel bottom formwork and the steel box girder and crossbeams. Measure the dimensions between the two crossbeams on both longitudinal sides of the installed steel bottom formwork in advance, and measure the length and width dimensions of the steel bottom formwork at the corresponding locations, then analyze the data.

[0055] Understand the structural formwork of the steel bottom formwork and determine the overlap between the steel bottom formwork and the steel box girder and crossbeam.

[0056] When hoisting the steel bottom formwork, ensure that no one stands within the swing radius of the crane boom. When hoisting between the beams, ensure that all four sides of the steel bottom formwork overlap with the beams and the upper flange of the steel box girder.

[0057] Position the steel bottom formwork using the perforated plate (shear member) on the installed steel bottom formwork as a reference, ensuring that the linearity of the perforated plate on the installed steel bottom formwork is consistent with that of the perforated plate on the installed steel bottom formwork.

[0058] The steel bottom formwork shall be spot-welded as required, with a spot weld length of not less than 40mm and a spot weld spacing of 300mm to 600mm. If there is a gap between one side of the steel bottom formwork and the steel box girder and crossbeams, and the overlap requirements are not met, the steel bottom formwork shall be fixed to the steel box girder and crossbeams with a support plate. Before the steel bottom formwork is fixed to the steel box girder and crossbeams, no one shall walk or step on it.

[0059] Weld fillet welds between the steel bottom formwork and the steel box girder and crossbeams according to the welding process requirements. Weld the welds between the installed steel bottom formwork perforated plate (shear joint) and the installed steel bottom formwork perforated plate, and grind the welded areas.

[0060] The welded areas were repainted according to the painting process, and the damaged paint on the steel base mold was also repainted.

[0061] Initial tightening: The operation of initially tightening high-strength bolts using a wrench with uniform torque or handle length. The initial tightening torque is 50% of the final tightening torque.

[0062] Re-tightening: This is an operation performed to eliminate the reduction in preload of the bolts caused by tightening them later. The re-tightening torque is equal to the initial tightening torque. After high-strength bolts have been retightened and passed inspection, a mark is made with paint at the junction of the nut and the bolt. Bolts without this mark cannot be fully tightened.

[0063] Final tightening: The tightening operation performed to bring the axial force of the high-strength bolt to the design requirements. The final tightening torque is calculated using the following formula: T0=K·P2·d T0 — Final tightening torque (kN·m) K—The average torque coefficient measured on-site for the same batch number.

[0064] P2—Pre-tension force (KN) for high-strength bolts during construction, as described above.

[0065] d—Nominal diameter of high-strength bolt (mm) To ensure that the bolt preload error is within ±10% of the design value, the final tightening torque should be adjusted in a timely manner according to the changes in the torque coefficient (such as the difference in the average torque coefficient of each batch of bolts and the influence of the temperature change on the torque coefficient).

[0066] Electric wrenches with fixed torque and dial wrenches displaying torque should be numbered before use. For each electric wrench and controller, the knob of the controller should not be adjusted arbitrarily during use, and it should be used by a designated person.

[0067] After final tightening, the re-tightening paint marks on the nut and screw should be misaligned; those that are not misaligned are bolts that were not fully tightened.

[0068] The initial tightening, retightening, and final tightening of high-strength bolt assemblies should be completed within the same working day.

[0069] Based on the same technical concept, in a second aspect, the present invention proposes an installation device for steel box girders, which is used to perform the steel box girder assembly construction method for reducing residual stress as described in the first aspect.

[0070] The above description is merely an optional embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for assembling and constructing steel box girders to reduce residual stress, characterized in that, Includes the following steps: Several segments to be assembled and a temporary two-piece assembly frame are prepared at a pre-designated material preparation site; wherein, a reference axis is provided on the temporary two-piece assembly frame along its extension direction; The first section to be assembled is hoisted and placed on the temporary two-piece assembly frame, and the first section to be assembled is adjusted so that its central axis overlaps with the reference axis; The second section to be assembled is hoisted and placed on the temporary two-piece assembly frame, and the second section to be assembled is adjusted so that its central axis overlaps with the reference axis; wherein the second section to be assembled is adjacent to the first section to be assembled. Welding is performed at the connection points between the first segment to be assembled and the second segment to be assembled, so that the first segment and the second segment are connected to form an integral structure; The overall structure is hoisted and installed in the preset construction area, and the steps of hoisting and placing the first section to be assembled on the temporary two-piece assembly frame and adjusting the first section to be assembled so that its central axis overlaps with the reference axis are repeated until the installation of all the overall structures in the preset construction area is completed, forming the steel box girder.

2. The method for assembling and constructing steel box girders to reduce residual stress as described in claim 1, characterized in that, After the step of preparing several segments to be assembled and a temporary two-piece assembly frame at the pre-designated material preparation site, the method further includes: Several detection points are set on each of the segments to be assembled; wherein the detection points are distributed at intervals along the length extension direction, width extension direction, height extension direction, side bend position, and preset arch bend position of the segment to be assembled.

3. The method for assembling and constructing steel box girders to reduce residual stress as described in claim 2, characterized in that, After the steps of hoisting and placing the first section to be assembled onto the temporary two-piece assembly frame, and adjusting the first section to be assembled so that its central axis overlaps with the reference axis, the method further includes: The detection points are inspected to obtain the detection parameters of the first segment to be assembled; wherein, the detection parameters include the length, width, height, lateral curvature, and preset arch angle of the first segment to be assembled.

4. The method for assembling and constructing steel box girders to reduce residual stress as described in claim 3, characterized in that, The step of welding the connection between the first segment to be assembled and the second segment to be assembled, so that the first segment and the second segment are connected to form an integral structure, includes: A code plate is set at the connection position between the first section to be assembled and the second section to be assembled, so as to adjust the misalignment between the first section to be assembled and the second section to be assembled through the code plate; Welding is performed at the connection points to connect the first segment and the second segment to form an integral structure.

5. The method for assembling and constructing steel box girders to reduce residual stress as described in claim 4, characterized in that, The step of setting a code plate at the connection position between the first segment to be assembled and the second segment to be assembled, so as to adjust the misalignment between the first segment to be assembled and the second segment to be assembled through the code plate, includes: A code plate is set at the connection position between the first section to be assembled and the second section to be assembled, so as to adjust the misalignment between the bottom web plate of the first section to be assembled and the bottom web plate of the second section to be assembled; wherein, the misalignment is A, and A≤0.5mm.

6. The method for assembling and constructing steel box girders to reduce residual stress as described in claim 4, characterized in that, The step of welding the connection at the connection position to connect the first segment and the second segment to form an integral structure includes: Welding is performed at the connection points to connect the first segment and the second segment to form the current segment; The current segment is inspected and polished to obtain the overall structure.

7. The method for assembling and constructing steel box girders to reduce residual stress as described in claim 6, characterized in that, The steps of performing inspection and polishing operations on the current segment to obtain the overall structure include: Perform flaw detection on the current segment; After the flaw detection operation is completed, the current segment is ground to obtain the overall structure.

8. The method for assembling and constructing steel box girders to reduce residual stress as described in claim 7, characterized in that, The step of grinding the current segment after the flaw detection operation to obtain the overall structure includes: After the flaw detection operation is completed, the arc-starting plates at each weld position of the current segment are flame-cut and ground, and the flatness of the weld position is adjusted to B to obtain the overall structure; wherein, B≤1mm / m.

9. The method for assembling and constructing steel box girders to reduce residual stress as described in claim 5, characterized in that, The steps of performing flame cutting and grinding operations on the arc-starting plates at each weld position of the current segment after the flaw detection operation is completed, and adjusting the flatness of the weld position to B to obtain the overall structure, include: After the flaw detection operation is completed, the arc-starting plates at each weld position of the current segment are flame-cut and ground, and the flatness of the weld position is adjusted to B. After the flatness adjustment is completed, each of the welds is touched up with paint to obtain the overall structure.

10. An installation device for steel box girders, characterized in that, The installation equipment for the steel box girder is used to perform the steel structure box girder assembly construction method for reducing residual stress as described in any one of claims 1 to 9.

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