Manufacturing method of super-long twisted box girder

Abstract

The invention relates to the technical field of steel structure manufacturing, in particular to a manufacturing method of a super-long twisted box girder, which comprises the following steps of: performing three-dimensional modeling and segmenting; establishing coordinates and manufacturing a mould; manufacturing a segmented box girder main body; corbel clamping heads are manufactured; bracket clamping heads are positioned and installed; and integrally assembling. According to the method, segmentation, mould manufacturing and part positioning are guided through a digital model, personal errors are greatly reduced, and the forming precision of complex space modeling is guaranteed; the super-long twisted box girder is manufactured in an industrialized and segmented mode, the working environment is stable, quality control is facilitated, and the influence of adverse conditions on welding and forming is avoided; in addition, erection of an overall rectangular jig frame and correction of complex procedures can be avoided, the production cycle and construction cost of a single piece are shortened through segmented manufacturing, and the problem that super-long components are difficult to transport is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steel structure manufacturing, in particular to a manufacturing method of super-long twisted box girder. BACKGROUND

[0002] The twisted box girder is widely used in the roof and facade design of modern public buildings (such as theaters, stations and airports) due to its unique architectural aesthetic performance, clear stress characteristics and wide span adaptability. For example, 39 super-long twisted steel structure box girders with a length of more than 60 meters are used in the dome structure of the Beijing City Green Heart project of the subway.

[0003] However, such components usually have different shapes, large space twisting angles, a large number of splicing nodes (such as bracket clamps) and high positioning accuracy requirements. If the traditional whole manufacturing or conventional segmented method is used, many problems are faced: first, the whole manufacturing needs to set up a giant special-shaped jig with the same length as the component, which is costly and occupies a large amount of space; second, large-area heating and roasting of long strip steels are needed to form the twisted shape, which not only has a complex process and low efficiency, but also easily causes material property changes and uncontrollable deformation, resulting in poor final forming precision; in addition, the transportation of super-long components is almost an insurmountable obstacle in actual engineering.

[0004] Therefore, there is an urgent need for an innovative manufacturing method of super-long twisted box girder which can ensure precision, improve efficiency, reduce cost and facilitate transportation. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a manufacturing method of super-long twisted box girder to overcome the problems of large span, complex shape, high node positioning accuracy and the like of the super-long twisted box girder.

[0006] The technical scheme adopted by the present application to solve its technical problems is: A manufacturing method of super-long twisted box girder, which is performed according to the following steps: S1, three-dimensional modeling and segmentation: a three-dimensional modeling software is used to establish an overall model of the super-long twisted box girder, a plurality of section point groups are selected according to the structural characteristics, and the entire super-long twisted box girder is divided into a plurality of segments; S2, coordinate establishment and jig making: the model is imported into a CAD software, a front view X-Z coordinate system and a plan view X-Y coordinate system are constructed respectively; points are taken along the X axis at a fixed interval in the two coordinate systems, and perpendicular lines are made to intersect with the contour line of the box girder bottom plate to obtain three-dimensional space control points, and a jig for the box girder bottom plate is made according to the coordinate data of the control points; S3, segmented box girder main body manufacturing: the bottom plate, the web plate, the partition plate and the upper cover plate are assembled in sequence on the jig, and are welded to form a segmented box girder main body; S4, bracket shoe manufacturing: using the contour line plane lofting method to manufacture bracket shoes; that is, drawing the projection contour line of the bracket shoe on the horizontal working surface according to the 1:1 proportion, positioning and welding each part plate of the bracket shoe according to the contour line; S5, bracket shoe positioning and installation: measuring the line segment distance and angle between the two points of the box girder main body end and the two points of the bracket shoe end by using the string angle measuring scale, and positioning and welding the manufactured bracket shoe on the segmented box girder main body according to the distance and angle; S6, overall assembly: after the box girder is manufactured, the section point group set in the model is accurately connected, and the interface position is welded and fixed after the connection is completed, so that the manufacturing of the super-long twisted box girder is completed.

[0007] Compared with the prior art, the beneficial effects of the present application are: The present application can greatly reduce human error and ensure the forming precision of complex space modeling by using digital model to guide segmentation, mold manufacturing and part positioning; the super-long twisted box girder is manufactured in a factory, the working environment is stable and the quality control is convenient, and the influence of adverse conditions on welding and forming is avoided; the present application can also avoid the erection of the overall rectangular jig frame and the complex correction process, the segmented manufacturing shortens the single-piece production cycle and construction cost, and solves the problem of difficult transportation of super-long components.

[0008] As preferred, the further technical scheme of the present application is: Preferably, in step S1, each section point group is composed of a plurality of points capable of representing the attitude of the box girder section, and each point group is marked with a unique code.

[0009] Preferably, in step S2, the fixed interval is 1200mm.

[0010] Preferably, the model of the bracket shoe is switched to the projection plane in the CAD software, the length of the outer contour line, the perpendicularity and the string angle data are obtained, and the data are laid out on the working platform in 1:1.

[0011] Preferably, the abutting plate is arranged at the abutting position of the two adjacent end segments. Since the interface of the two segmented box girders has poor strength, the abutting plate is arranged at the connecting position of the segmented box girder to strengthen the abutting strength of the box girder main body. DETAILED DESCRIPTION

[0012] Figure 1 is a structural schematic view of the super-long twisted box girder in the present application; Figure 2 is a schematic view of the section point group on the box girder in the present application; Figure 3 is a schematic view of the plane coordinate system established by the side view and top view of the component in the present application; Figure 4 is a contour line plane lofting view of the bracket shoe in the present application; Figure 5 Figure 1 is a structural schematic diagram of positioning bracket clamps by string angle measuring method; Mark explanation: 1, bracket clamp; 2, lap plate; DETAILED DESCRIPTION

[0013] The present application is further described below in conjunction with specific embodiments, and the purpose is only to better understand the content of the present application, therefore, the examples do not limit the protection scope of the present application.

[0014] A method for manufacturing an ultra-long twisted box girder is performed according to the following steps: S1, three-dimensional modeling and segmentation: an overall model of the ultra-long twisted box girder is established by using TEKLA modeling software, according to the number of bracket clamps on the ultra-long twisted box girder and the distribution of the bracket clamps on the surface of the ultra-long twisted box girder, a plurality of section point groups are selected, and the entire ultra-long twisted box girder is divided into a plurality of segments; each section point group is composed of a plurality of points capable of representing the posture of the box girder section, and each point group is marked with a unique code.

[0015] S2, coordinate establishment and mold manufacturing: the model in step S1 is imported into CAD software to obtain CAD three-dimensional projection, and a front view X-Z coordinate system and a top view X-Y coordinate system are respectively constructed, vertical lines are respectively made along the X axis at a fixed interval in the two coordinate systems, the points where the vertical lines intersect the box girder bottom plate contour line are control points, the coordinate values of each point are recorded, and the three-dimensional coordinate points of each control point are obtained, and then the box girder bottom plate mold is manufactured according to the coordinate data of the control points.

[0016] S3, segmented box girder main body manufacturing: the U-shaped box girder can be manufactured by adding left and right side stops on both sides of the vertical mold based on the box girder bottom plate mold, the inner partition plate is installed according to the detailed drawing, the cover plate is covered after the installation of the inner partition plate is completed, and the inner partition plate is welded to the welding position of the cover plate by electroslag welding, and the segmented box girder main body manufacturing is completed.

[0017] S4, bracket clamp manufacturing: after the segmented box girder is manufactured, the bracket clamps on the box girder need to be manufactured, the bracket clamps are manufactured by contour line plane lofting method, that is, the projection plane of the bracket clamp model is adjusted in the CAD software to obtain the length of the outer contour line, the perpendicularity and the string angle, and the contour line is drawn on the working platform by 1:1 real lofting according to the data, and the bracket clamp parts are positioned and welded according to the contour line.

[0018] S5, bracket clamp positioning and installation: the distance and angle between the two points at the end of the box girder main body and the two points at the end of the bracket clamp are measured by string angle ruler method, and the manufactured bracket clamp is positioned on the segmented box girder main body and welded according to the distance and angle.

[0019] S6. Overall Assembly: After the box girder is fabricated, it is precisely connected according to the cross-section points set in the model. After the connection is completed, the interface is welded and fixed to complete the fabrication of the ultra-long torsional box girder.

[0020] In this embodiment, since the strength at the interface of the two segmented box girders is poor, an overlap plate is added at the connection position of the segmented box girders to strengthen the joint strength of the main body of the box girder.

[0021] Based on the above steps, Figure 1 Taking the ultra-twisted box girder shown as an example, the box girder is 62m long, has a spatially twisted shape, a total lateral bending of 8462mm, and an camber of 870mm. It consists of a box-shaped main body with cross-sectional dimensions of BOX600*350*30*40, 14 corbel brackets, and several internal diaphragms, forming the ultra-long twisted box girder, as detailed below: S1. 3D Modeling and Segmentation: For example... Figure 2 As shown, a precise model of the box girder was created in TEKLA software. Based on the distribution of the 14 bracket clamps, the model was divided into four segments, with the first segment exhibiting the greatest degree of torsion. The first and second segments each had four bracket clamps, while the third and fourth segments each had three. Since the connection between adjacent segments is a box girder-to-box girder butt joint, cross-section point groups were established based on the four points corresponding to the four corners of the rectangular cross-section at the box girder end. For example, in the first set of joints, the right box girder was marked A, B, C, D counter-clockwise from the upper right corner, and the left box girder was marked A, B, C, D clockwise from the upper left corner. The second set of joints was marked E, F, G, H, and the third set was marked I, G, K, L. This unique coding of the cross-section point groups ensured accurate sequence during docking.

[0022] S2. Coordinate Establishment and Fixture Making: (e.g.) Figure 3 As shown, the first segment of the box girder is selected. The model of the first segment of the box girder is imported into CAD software using TEKLA software to observe its specific torsion. The component is then projected in both front and top views. XZ and XY coordinate systems are established in CAD through these projections. In the front view, set the far point O1 500mm below the left end of the bottom plate of the box girder. Draw an XZ rectangular coordinate system based on the origin of the coordinate system. Mark an intermediate point every 1200mm along the X axis. Draw a vertical line in the Z direction from this point. The point where the vertical line intersects with the edge line of the bottom plate is the height control point of the main body of the tortuous box girder. Record the Z coordinate of each height control point. In the top view, set the origin O2 500mm below the left end of the base plate. Draw an XY rectangular coordinate system based on the origin. Similarly, mark an intermediate point every 1200mm along the X axis. Draw a vertical line in the Y direction from this point. The point where the vertical line intersects the edge line of the base plate is the side curve control point. Record the Y coordinate of each side curve control point. Then, by combining the X (1200mm spacing), Y, and Z coordinates of each point, a series of three-dimensional coordinates of control points are obtained. Based on this data matrix, workers create a base plate jig on the platform that perfectly matches the twisted base plate. Then, vertical baffles are installed on both sides of the jig to assist in positioning the left and right webs of the segmented box girder.

[0023] S3. Segmented Box Girder Main Structure Fabrication: On the base plate jig, first position and fix the base plate, then erect the two side web plates and spot weld them to the base plate and jig side baffles. According to the drawings, measure inward from the end of the box girder to determine the position of each internal partition and assemble them. Finally, install the cover plate and use welding processes such as electroslag welding to complete the welding of the cover plate to the web plates and partitions, forming the complete first segmented box girder. Fabricate the remaining segments according to steps 2 and 3.

[0024] S4. Making the cow leg clip: (e.g., ...) Figure 4 As shown, after all the segmented box girders are manufactured, the corbel clips on each segmented box girder are manufactured. Taking one corbel clip as an example, the corbel clip is composed of four regular 20mm thick plates of different shapes, of which the left and right plates are rectangular and the top and bottom plates are crescent-shaped.

[0025] First, use the UCS command in the CAD software to set the origin of the coordinate system on the bracket head, flip it to the front horizontal position, then use the PLAN command to open the top view angle, and switch to the top view angle using the PLAN command. Use polylines to draw the outer contour of the bracket head, and measure the side length, perpendicularity, and cross angle of the contour line. On the workshop work platform, based on these parameters, you can use a pen to draw the contour on the work plane at a 1:1 scale. Assemble and weld the four parts according to the lines, and the bracket seat is completed. Repeat the above steps to make the remaining bracket seats.

[0026] S5. Bracket clamp positioning installation: such as Figure 5 As shown, the distance and angle between the two points at the ends of the box girder and the two points at the ends of the corbel clip are measured using the angle measuring method. Based on this, the fabricated corbel clip is positioned on the segmented box girder and welded. Taking the installation of the first corbel clip as an example, in the CAD model, lines are drawn from the ends P and Q of the box girder to the points M and N of the corbel clip, respectively. The lengths L1 and L2 of the line segments PN and QM, as well as the angles α1 and α2 between these line segments and the edge of the box girder, are accurately measured. Then, on the actual segmented box girder, the corresponding points P and Q in the model are found. Using the measured L1, L2, α1, and α2, the points M and N on the box girder can be determined by using a measuring tape and a protractor, thus accurately positioning the corbel clip. Finally, the clip is welded to the box girder.

[0027] S6. Overall Assembly: After the box girder is fabricated, it is transported to the site. At the assembly site, the corresponding points of adjacent end box girders are aligned strictly according to the section point group code. After checking that there are no errors, they are welded. After welding, anti-corrosion treatment is carried out, and the ultra-long tortuous box girder is completed.

[0028] This invention uses digital models to guide segmentation, jig fabrication, and part positioning, greatly reducing human error and ensuring the forming accuracy of complex spatial shapes. The factory segmentation fabrication of ultra-long tortuous box girders provides a stable working environment and facilitates quality control, avoiding the impact of adverse conditions on welding and forming. This invention also avoids the erection of an integral rectangular jig and the correction of complex processes. Segmentation fabrication shortens the production cycle and construction cost of a single piece, and also solves the problem of difficult transportation of ultra-long components.

[0029] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. All equivalent changes made based on the description and drawings of the present invention are included within the scope of the present invention.

Claims

1. A method for manufacturing an ultra-long torsional box girder, characterized in that, Follow these steps: S1. 3D Modeling and Segmentation: Use 3D modeling software to create an overall model of the ultra-long twisted box girder, select multiple cross-sectional point groups according to structural characteristics, and divide the entire ultra-long twisted box girder into several segments. S2. Coordinate Establishment and Fixture Fabrication: Import the model into the CAD software and construct the XZ coordinate system of the front view and the XY coordinate system of the top view respectively. In the two coordinate systems, take points along the X-axis at fixed intervals and make a perpendicular line to intersect with the outline of the box girder bottom plate to obtain three-dimensional space control points. Based on the coordinate data of the control points, make the fixture for the box girder bottom plate. S3. Segmented box girder main body fabrication: The bottom plate, web plate, diaphragm and top cover plate are assembled sequentially on the jig and welded to form the segmented box girder main body; S4. Bracket Head Fabrication: The bracket head is fabricated using the outline planar lofting method; that is, the projected outline of the bracket head is drawn on the horizontal working surface at a 1:1 scale, and the various parts of the bracket head are positioned and welded according to the outline. S5. Bracket clamp positioning and installation: The line segment distance and angle between two points on the end of the box girder and two points on the end of the bracket clamp are measured using the angle measuring ruler method. Based on this, the prepared bracket clamp is positioned on the segment box girder and welded. S6. Overall Assembly: After the box girder is fabricated, it is precisely connected according to the cross-section points set in the model. After the connection is completed, it is welded and fixed at the interface to complete the fabrication of the ultra-long torsional box girder.

2. The method for manufacturing an ultra-long torsional box girder according to claim 1, characterized in that: In step S1, each cross-section point group consists of multiple points that can represent the orientation of the box girder cross-section, and each point group is marked with a unique code.

3. The method for manufacturing an ultra-long torsional box girder according to claim 1, characterized in that: In step S2, the fixed spacing is 1200mm.

4. The method for manufacturing an ultra-long torsional box girder according to claim 1, characterized in that: In step S4, the projection plane of the cow leg head model is switched in the CAD software to obtain the side length, perpendicularity and cross angle data of its outer contour line, and the model is laid out on the work platform at a 1:1 scale based on the data.

5. The method for manufacturing an ultra-long torsional box girder according to claim 1, characterized in that: Overlap plates are provided at the joints where adjacent ends are connected in segments.

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