Method for linear control of steel box girder

Abstract

The application provides a linear control method of a steel box girder, comprising the following steps: S1, determining the distance between each axis in the steel bridge and the distance from each axis to the starting point; S2, calculating the height difference in the width direction of the steel bridge; S3, calculating the pre-arch value of the steel bridge; S4, calculating the three-dimensional coordinates of the cambered surface; and S5, after the three-dimensional coordinates are converted into two-dimensional coordinates, construction operation is carried out. The linear control method of the steel box girder is mainly used for illustrating how to control the horizontal curve, the vertical curve and the cambered surface curve, integrating the cambered surface curve with the horizontal curve and the vertical curve for joint action, and calculating more accurate positioning coordinate data through rigorous and reasonable derivation, so as to solve the problems of low production efficiency and increased production cost caused by single curve control.

Description

Technical Field

[0001] This invention belongs to the field of steel box girder manufacturing, and in particular relates to a method for controlling the alignment of steel box girders. Background Technology

[0002] Existing elevated bridge steel box girders are characterized by large spans, complex alignments, and difficult positioning. To ensure that steel structure bridges are manufactured accurately and rationally according to the design plan, production staff need to thoroughly analyze the bridge's alignment, understand its variation patterns, and control the factors influencing these variations. This is essential for achieving precise coordinate positioning of the steel structure bridge. Currently, the alignments of steel structure bridges mainly include horizontal and vertical curves. In the past, production processes often involved controlling each individual alignment individually, which frequently led to alignment deviations and repeated corrections. This not only wasted significant manpower and resources but also greatly reduced the efficiency of steel structure bridge production, making it impossible to complete production tasks on schedule and impacting project progress. Summary of the Invention

[0003] In view of this, the present invention aims to propose a method for controlling the alignment of steel box girders, in order to solve the problem of reduced production efficiency and increased production costs caused by controlling a single curve one by one.

[0004] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0005] The method for controlling the alignment of steel box girders includes the following steps:

[0006] S1. Determine the spacing between the axes inside the steel bridge, and the distance from each axis to the starting point;

[0007] S2. Calculate the elevation difference in the width direction of the steel bridge and calculate and control the horizontal curves in the steel bridge.

[0008] S3. Calculate the pre-arch value of the steel bridge and calculate and control the vertical curves in the steel bridge;

[0009] S4. Calculate the three-dimensional coordinates of the curved surface;

[0010] S5. After converting the three-dimensional coordinates into two-dimensional coordinates, construction work is carried out.

[0011] The calculation method for step S2 is to calculate based on the preset slope value of the steel structure bridge, and based on the specific values ​​of the height difference between the left and right sides and the bridge width length from the left and right sides to the center line of the road.

[0012] The calculation method for step S3 is to calculate based on the preset camber of the steel bridge. On the basis of the preset camber value, a workshop camber value of not less than three ten-thousandths of the bridge span is added to each span of the bridge during construction. The vertical curve is calculated using the principle of a quadratic parabola based on the known camber value and bridge span value.

[0013] The calculation method for step S4 includes the following steps:

[0014] A1. Perform control calculations on the arc curve to obtain the coordinate values ​​of the road centerline. The arc curve is controlled by the combined action of horizontal and vertical curves.

[0015] A2. Using the coordinates of the road centerline and the positional relationship between the web of the steel bridge and the road centerline, the contour data of the web is derived and calculated.

[0016] A3. Derive and calculate the elevations of the upper and lower chords of the web;

[0017] The calculation method for step A3 is to first calculate the bridge deck elevation of the road centerline:

[0018] After calculating the bridge deck elevation of the road centerline, use the data to calculate the top elevation of the top slab and the bottom elevation of the top slab of the road centerline:

[0019] The top / bottom elevations of the top slab of the left / right box girder centerline are determined by the elevations of the top / bottom surfaces of the top slab of the road centerline, the distances of the centerlines of the left / right box girders from the road centerline, and the cross slope.

[0020] After the elevation calculation of the top plate of the left / right centerline is completed, preparations begin for calculating the elevation of the bottom plate of the left / right centerline. First, the variation value of the web beam height at each location needs to be derived and calculated according to the design requirements. The web beam height varies according to a 1.8-degree parabola. After calculating the variation value of the web beam height, the elevation calculation of the bottom plate of the left / right centerline is then performed.

[0021] After calculating the elevation of the top / bottom plate of the left / right centerline, the elevation of the top / bottom plate of the left / right side web is calculated based on the elevation of the top / bottom plate of the left / right centerline.

[0022] Furthermore, the elevation difference to the left of the bridge-road centerline is as follows:

[0023] H 左 =△L 左 *i 左 ;

[0024] Elevation difference to the right of the bridge / road centerline:

[0025] H 右 =△L 右 *i 右

[0026] In the formula H 左 / 右 This refers to the elevation difference between the left and right sides of the bridge / road centerline.

[0027] △L 左 / 右 The width of the bridge on the left / right side of the road centerline;

[0028] i 左 / 右 The slope values ​​for the left and right sides of the bridge / road centerline;

[0029] The calculation of the preset pre-arch value is as follows:

[0030] Y1 = a1X1² + b1X1 + c1;

[0031] Where: Y1—Design camber value for each axis;

[0032] X1 — Distance of each axis from the origin;

[0033] a1, b1, c1 — constant values;

[0034] Workshop camber value calculation:

[0035]

[0036] In the formula: Y2—design camber value for each axis;

[0037] X2 — the distance of each axis from the origin;

[0038] a2, b2, c2 — constant values;

[0039] The calculation method for step A2 is: X 左 / 右 =X0+△Z / YL0*sinθ

[0040] Y 左 / 右 =Y0+△Z / YL0*cosθ

[0041] In the formula X 左 / 右 The X-coordinate values ​​of the left / right side web contours;

[0042] The Y-coordinate value of the left / right side web profile;

[0043] This represents the Y-coordinate of the road centerline.

[0044] X0 is the X-coordinate value of the road centerline;

[0045] △Z / YL0 is the distance between the left / right web and the center line of the road;

[0046] θ is the angle between the normal and the perpendicular;

[0047] The method for calculating the bridge deck elevation of the road centerline is as follows:

[0048] H0=H i +△H

[0049] In the formula, H0 represents the bridge deck elevation along the road centerline.

[0050] H i —Design theoretical elevation;

[0051] △H—Total camber value;

[0052] The method for calculating the top surface elevation of the top slab and the bottom surface elevation of the top slab of the road centerline using its data is as follows:

[0053] H 0顶1 =H0-P;

[0054] H 0顶2 =H 0顶1 -T i .

[0055] In the formula H 0顶1 —Elevation of the top surface of the slab above the road centerline;

[0056] H0—Bridge deck elevation along the road centerline;

[0057] P—Thickness of the paving layer;

[0058] H 0顶2 —Elevation of the top and bottom surfaces of the road centerline;

[0059] Ti – Top plate thickness;

[0060] The method for determining the top / bottom elevation of the top plate of the left / right box girder centerline is as follows:

[0061] ZFH 0顶1 =H 0顶1 -△ZFL0*i1;

[0062] YFH 0顶1 =H 0顶1 +△YFL0*i2;

[0063] Z / YFH 0顶2 =Z / YFH 0顶1 -T i .

[0064] In the formula ZFH 0顶1 —Elevation of the top surface of the top plate along the centerline of the left box girder;

[0065] △ZFL0——Distance between the centerline of the left box girder and the centerline of the road;

[0066] i1 — Slope value of the left transverse slope;

[0067] YFH 0顶1 —Elevation of the top surface of the top plate along the centerline of the right-side box girder;

[0068] i2 — Slope value of the right-side cross slope;

[0069] △YFL0—Distance between the centerline of the right box girder and the centerline of the road;

[0070] Z / YFH 0顶2 —Elevation of the top surface of the centerline of the left / right box girder;

[0071] After calculating the change in web beam height, the elevation of the bottom plate along the left / right centerline is calculated as follows:

[0072] Z / YFH 0底1 =Z / YFH 0顶2 -△FL0;

[0073] Z / YFH 0底2 =Z / YFH 0底1 -D i .

[0074] In the formula Z / YFH 0底1 —Elevation of the top surface of the bottom plate along the left / right centerline;

[0075] △FL0—Change in web beam height;

[0076] Z / YFH 0底2 —Elevation of the bottom surface of the left / right centerline plate;

[0077] D i —Base plate thickness;

[0078] The elevations of the top and bottom plates of the left and right side webs are calculated based on the elevations of the top and bottom plates of the left and right centerlines, as follows:

[0079] ZFBH 顶1 =ZFH 0顶1 -△ZFBL0*i1;

[0080] YFBH 顶1 =YFH 0顶1 +△YFBL0*i2;

[0081] Z / YFBH 顶2 =Z / YFBH 顶1 -T i ;

[0082] Z / YFBH 底1 =Z / YFBH 顶2-△FL0;

[0083] Z / YFBH 底2 =Z / YFBH 底1 -D i .

[0084] In the formula ZFBH 顶1 —Elevation of the top surface of the left side web;

[0085] △ZFBL0——The distance from the left side web to the left centerline web;

[0086] YFBH 顶1 —Elevation of the top surface of the right side web;

[0087] △YFBL0——The distance from the right side web to the right centerline web;

[0088] Z / YFBH 顶2 —Elevation of the top and bottom surfaces of the left / right side webs;

[0089] Z / YFBH 底1 —Elevation of the top surface of the bottom plate of the left / right side web;

[0090] Z / YFBH 底2 —Elevation of the bottom surface of the left / right side web plate.

[0091] Compared with existing technologies, the steel box girder alignment control method of the present invention has the following advantages:

[0092] (1) The alignment control method for steel box girders described in this invention can accurately and reasonably control the alignment of steel structure bridges according to the design plan. In the early preparation stage, this invention can be used to refine the design drawings. The design drawings are transformed into detailed construction drawings that can be specifically produced and processed, making it easier for the workers in charge of production to understand the contents of the drawings.

[0093] (2) The alignment control method for steel box girders described in this invention can effectively solve problems such as large span, complex alignment, and difficult positioning of steel structure bridges, transforming complex three-dimensional spatial planes into simple two-dimensional spatial planes. During production, plate processing can be performed directly, and the accuracy requirement of controlling the dimensional error of parts within ±2mm can be met. This provides great convenience for the production work in the workshop.

[0094] (3) The linear control method for steel box girders described in this invention utilizes widely applicable three-dimensional spatial coordinates. After production, a jig is required for assembly. This invention can be used to calculate and control the positioning data for both the initial jig setup and the positioning data during assembly on the jig. The data from this invention meets the accuracy requirements of controlling the X and Y value errors within ±2mm during jig setup, the elevation error between adjacent points within ±2mm, and the elevation difference error between any two points within ±3mm. This significantly improves the efficiency of the manufacturing process and saves substantial manpower and material costs.

[0095] (4) The linear control method for steel box girder described in this invention can be used directly when using modeling software for three-dimensional modeling, providing effective data technology support for the establishment of three-dimensional models.

[0096] (5) The steel box girder alignment control method described in this invention employs a scientific and reasonable calculation method, which greatly improves the accuracy of the data. Simultaneously, the calculation process is highly concise, allowing for the solution of the alignment control problem for steel structure bridges through simple calculations. These convenient and precise features safeguard the production quality of steel structure bridges. Detailed Implementation

[0097] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0098] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," indicating orientation or positional relationships, are merely for the convenience of describing the 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 invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0099] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0100] The present invention will be described in detail below with reference to the embodiments.

[0101] In controlling the alignment of steel structure bridges, the first step is to determine the axle spacing and the distance from each axis line in each span to the starting point. After determining the axle spacing and cumulative axle spacing, the coordinate positioning calculation for the alignment begins.

[0102] 1. Calculation of elevation difference in the width direction of the steel bridge

[0103] First, the horizontal curves in the steel bridge need to be calculated and controlled. This is mainly based on the slope values ​​of the steel bridge given in the design documents. There are usually left and right elevation differences. The calculation is performed based on the specific values ​​of the left and right elevation differences and the bridge width from the left and right sides to the road centerline. The specific calculation process is as follows:

[0104] Elevation difference to the left of the bridge / road centerline:

[0105] H 左 =△L 左 *i 左 ;

[0106] Elevation difference to the right of the bridge / road centerline:

[0107] H 右 =△L 右 *i 右 .

[0108] In the formula H 左 / 右 —Elevation difference between the left and right sides of the bridge / road centerline;

[0109] △L 左 / 右 —Bridge width to the left / right of the road centerline;

[0110] i 左 / 右 —Slope values ​​on the left / right sides of the bridge / road centerline.

[0111] 2. Calculation of pre-arch value for steel bridge

[0112] Further calculations and controls are performed on the vertical curve of the steel structure bridge. These calculations are primarily based on the pre-camber specified in the bridge design documents. However, during bridge construction, an additional 0.03% of the span distance is added to each span to compensate for settlement during pre-assembly and installation, ensuring the design pre-camber is achieved. The vertical curve is calculated using the known camber and bridge span values, applying the principles of a quadratic parabola. The specific calculation process is as follows:

[0113] Calculation of design pre-camber value:

[0114] Y1 = a1X1² + b1X1 + c1;

[0115] Where: Y1—Design camber value for each axis;

[0116] X1 — Distance of each axis from the origin;

[0117] a1, b1, c1 — constant values.

[0118] Workshop camber value calculation:

[0119] Y2 = a2X2² + b2X2 + c2;

[0120] In the formula: Y2—design camber value for each axis;

[0121] X2 — the distance of each axis from the origin;

[0122] a2, b2, c2 — constant values.

[0123] 3. Calculation of three-dimensional coordinates of curved surfaces

[0124] Further calculations and controls are performed on the curved surface. The curved surface is controlled by the combined action of horizontal and vertical curves. In the production and manufacturing process of steel structure bridges, it is necessary to clarify the coordinate positioning of the curved surface in three-dimensional space to facilitate its placement on the jig for assembly. It is also necessary to unfold it to meet the needs of workers for production and processing on a two-dimensional plane.

[0125] The process of controlling the calculation of the arc surface curve is as follows:

[0126] First, by analyzing the shape of the transition curve, the radius of curvature, the angle between the normal and the perpendicular, and the X and Y coordinates of the road centerline are derived by using the design-given values ​​of the circular curve radius R, the minimum length of the transition curve Ls, and the distance from the vertex.

[0127]

[0128]

[0129] In the formula, These are the X and Y coordinates of point A on the transition curve, respectively. Let A be the distance from point A to the starting point O of the transition curve;

[0130] By utilizing the coordinates of the road centerline and the positional relationship between the web of the steel bridge and the road centerline, the contour data of the web is derived and calculated. The X-coordinate values ​​and Y-coordinate values ​​of the left / right web contours in this project are as follows:

[0131] X 左 / 右 =X0+△Z / YL0*sinθ

[0132] Y 左 / 右 =Y0+△Z / YL0*cosθ

[0133] In the formula X 左 / 右 —X-coordinate values ​​of the left / right side web contours;

[0134] —Y coordinate values ​​of the left / right side web contours;

[0135] —The Y-coordinate value of the road centerline;

[0136] X0 — The X-coordinate value of the road centerline;

[0137] △Z / YL0——Distance between the left / right web and the centerline of the road;

[0138] θ — the angle between the normal and the perpendicular.

[0139] After calculating the profile data of the left and right webs, the derivation and calculation of the elevations of the upper and lower chords of the webs begins. First, the bridge deck elevation along the road centerline must be calculated:

[0140] H0=H i +△H

[0141] In the formula, H0 represents the bridge deck elevation along the road centerline.

[0142] H i —Design theoretical elevation;

[0143] △H——Total arching value.

[0144] After calculating the bridge deck elevation of the road centerline, use the data to calculate the top elevation of the top slab and the bottom elevation of the top slab of the road centerline:

[0145] H 0顶1 =H0-P;

[0146] H0顶2 =H 0顶1 -T i .

[0147] In the formula H 0顶1 —Elevation of the top surface of the slab above the road centerline;

[0148] H0—Bridge deck elevation along the road centerline;

[0149] P—Thickness of the paving layer;

[0150] H 0顶2 —Elevation of the top and bottom surfaces of the road centerline;

[0151] Ti – Top plate thickness.

[0152] The top / bottom elevations of the top slab of the left / right box girder can be determined by the elevations of the top / bottom surfaces of the top slab of the road centerline, the distances of the centerlines of the left / right box girders from the road centerline, and the cross slope.

[0153] ZFH 0顶1 =H 0顶1 -△ZFL0*i1;

[0154] YFH 0顶1 =H 0顶1 +△YFL0*i2;

[0155] Z / YFH 0顶2 =Z / YFH 0顶1 -T i .

[0156] In the formula ZFH 0顶1 —Elevation of the top surface of the top plate along the centerline of the left box girder;

[0157] △ZFL0——Distance between the centerline of the left box girder and the centerline of the road;

[0158] i1—Left side cross slope;

[0159] YFH 0顶1 —Elevation of the top surface of the top plate along the centerline of the right-side box girder;

[0160] i2 – Right-side cross slope;

[0161] △YFL0—Distance between the centerline of the right box girder and the centerline of the road;

[0162] Z / YFH 0顶2 —Elevation of the top surface of the centerline of the left / right box girder.

[0163] After calculating the elevation of the top slab along the left / right centerlines, preparations begin for calculating the elevation of the bottom slab along the left / right centerlines. First, the variation values ​​of the web beam height at each location need to be derived and calculated according to the design requirements. The web beam height varies according to a 1.8-degree parabola. After calculating the variation values ​​of the web beam height, the elevation of the bottom slab along the left / right centerlines can be calculated.

[0164] Z / YFH 0底1 =Z / YFH 0顶2 -△FL0;

[0165] Z / YFH 0底2 =Z / YFH 0底1 -D i .

[0166] In the formula Z / YFH 0底1 —Elevation of the top surface of the bottom plate along the left / right centerline;

[0167] △FL0—Change in web beam height;

[0168] Z / YFH 0底2 —Elevation of the bottom surface of the left / right centerline plate;

[0169] D i —Base plate thickness.

[0170] After calculating the elevation of the top / bottom plate of the left / right centerline, the elevation of the top / bottom plate of the left / right side web can be calculated based on the elevation of the top / bottom plate of the left / right centerline:

[0171] ZFBH 顶1 =ZFH 0顶1 -△ZFBL0*i1;

[0172] YFBH 顶1 =YFH 0顶1 +△YFBL0*i2;

[0173] Z / YFBH 顶2 =Z / YFBH 顶1 -T i ;

[0174] Z / YFBH 底1 =Z / YFBH 顶2 -△FL0;

[0175] Z / YFBH 底2 =Z / YFBH 底1 -D i .

[0176] In the formula ZFBH 顶1 —Elevation of the top surface of the left side web;

[0177] △ZFBL0——The distance from the left side web to the left centerline web;

[0178] YFBH 顶1 —Elevation of the top surface of the right side web;

[0179] △YFBL0——The distance from the right side web to the right centerline web;

[0180] Z / YFBH 顶2 —Elevation of the top and bottom surfaces of the left / right side webs;

[0181] Z / YFBH 底1 —Elevation of the top surface of the bottom plate of the left / right side web;

[0182] Z / YFBH 底2 —Elevation of the bottom surface of the left / right side web plate.

[0183] 4. Converting 3D coordinates to 2D coordinates

[0184] After completing the three-dimensional spatial coordinate calculation, the spatial coordinate points on each axis are summarized, and then the three-dimensional coordinates are converted into two-dimensional coordinates according to the spatial coordinate formula, thereby obtaining the two-dimensional coordinate points. The calculation process is as follows:

[0185] Given that the origin of the coordinate system is (0, 0, 0) at the base plate along axis 1 in a three-dimensional coordinate system, and the lengths of the upper chord F1, lower chord F2, oblique chord F3, and height H of the web, the coordinate system is given. 腹 In the two-dimensional coordinate system, the origin is (0, 0).

[0186] Let the coordinates of the top plate of axis 1 be ( , ), determined by the web height H 腹1 We can obtain:

[0187]

[0188] Based on the orientation of the top and bottom slabs of the steel structure bridge, it can be inferred that , The specific positive and negative coordinates.

[0189] Let the coordinates of the top plate of axis 2 be ( , From the length of the web chord F1 and the length of the web oblique chord F3, we can obtain:

[0190]

[0191] Based on the orientation of the top and bottom slabs of the steel structure bridge, it can be inferred that , The specific positive and negative coordinates.

[0192] Let the coordinates of the base plate of axis 2 be ( , ), consisting of the lower chord length F2 of the web and the height H of the web. 腹2 We can obtain:

[0193]

[0194] Based on the orientation of the top and bottom slabs of the steel structure bridge, it can be inferred that , The specific positive and negative coordinates.

[0195] Based on the elevation of the left / right side webs and the X and Y values ​​of the left / right side web contours, determine the spatial coordinates of the upper and lower chords of the left / right side webs. Using these spatial coordinates, calculate the length of the upper chord, lower chord, oblique chord, and height of the webs. Then, using calculus and spatial triangle coordinate formulas, calculate the two-dimensional spatial coordinates of adjacent points. Following the calculation method described in the instructions, perform the calculations sequentially to obtain the coordinate data of the unfolded web shape. Import the data as a polyline into CAD software to obtain a complete unfolded planar curve.

[0196] 5. Implementation process

[0197] After obtaining the three-dimensional coordinates through this invention, a three-dimensional model can be established using the three-dimensional coordinates, which can create the web, diaphragm, etc. of the steel structure bridge in the model.

[0198] Detailed production and processing drawings can be exported from the established model.

[0199] Technicians use detailed drawings and nesting software to nest unit components and generate cutting programs for laser, plasma, flame, etc., that meet production requirements.

[0200] The production workshop cuts materials according to the detailed drawings and procedures. After the cutting is completed, the dimensions of the unit parts are checked to ensure that the dimensions of the unit parts meet the requirements of the allowable deviation dimensions of the parts.

[0201] After the unit components are assembled, the upper frame is assembled.

[0202] Before assembly, the jig can be set up using the three-dimensional coordinates calculated in this invention. The X and Y values ​​in the coordinates determine the orientation of the jig on the plane. The elevation value determines the height of the jig, ensuring that the jig is erected within the allowable error range.

[0203] This invention is mainly used in the process of controlling the alignment of steel structure bridges to ensure that the alignment of the manufactured steel structure bridges is consistent with the design and planning alignment.

[0204] Using this instruction manual for the alignment control of steel structure bridges allows for the detailed processing of drawings, transforming design drawings into detailed construction drawings that can be specifically produced and processed. Production workers can easily receive the information in the drawings and cut materials according to the drawings, with the cutting dimensions controlled within ±2mm of the process specifications.

[0205] This invention can accurately determine the three-dimensional spatial coordinates of steel structure bridges. By establishing a three-dimensional model using these coordinates, the overall alignment of the bridge can be visualized more intuitively. During the construction of the foundation, this invention can effectively control the X and Y coordinate values ​​on the foundation plane within ±2mm, the elevation error between adjacent points on the foundation within ±2mm, and the elevation difference error between any two points within ±3mm. This provides strong data support for the establishment of the three-dimensional model and the construction of the foundation.

[0206] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for controlling the alignment of steel box girders, characterized in that, Includes the following steps: S1. Determine the spacing between the axes inside the steel bridge, and the distance from each axis to the starting point; S2. Calculate the elevation difference in the width direction of the steel bridge and calculate and control the horizontal curves in the steel bridge. S3. Calculate the pre-arch value of the steel bridge and calculate and control the vertical curves in the steel bridge; S4. Calculate the three-dimensional coordinates of the curved surface; S5. After converting the three-dimensional coordinates into two-dimensional coordinates, construction work is carried out. The calculation method for step S2 is to calculate based on the preset slope value of the steel structure bridge, and based on the specific values ​​of the height difference between the left and right sides and the bridge width length from the left and right sides to the center line of the road. The calculation method for step S3 is to calculate based on the preset camber of the steel bridge. On the basis of the preset camber value, a workshop camber value of not less than three ten-thousandths of the bridge span is added to each span of the bridge during construction. The vertical curve is calculated using the principle of a quadratic parabola based on the known camber value and bridge span value. The calculation method for step S4 includes the following steps: A1. Perform control calculations on the arc curve to obtain the coordinate values ​​of the road centerline. The arc curve is controlled by the combined action of horizontal and vertical curves. A2. Using the coordinates of the road centerline and the positional relationship between the web of the steel bridge and the road centerline, the contour data of the web is derived and calculated. A3. Derive and calculate the elevations of the upper and lower chords of the web; The calculation method for step A3 is to first calculate the bridge deck elevation of the road centerline: After calculating the bridge deck elevation of the road centerline, use the data to calculate the top elevation of the top slab and the bottom elevation of the top slab of the road centerline: The top / bottom elevations of the top slab of the left / right box girder centerline are determined by the elevations of the top / bottom surfaces of the top slab of the road centerline, the distances of the centerlines of the left / right box girders from the road centerline, and the cross slope. After the elevation calculation of the top plate of the left / right centerline is completed, preparations begin for calculating the elevation of the bottom plate of the left / right centerline. First, the variation value of the web beam height at each location needs to be derived and calculated according to the design requirements. The web beam height varies according to a 1.8-degree parabola. After calculating the variation value of the web beam height, the elevation calculation of the bottom plate of the left / right centerline is then performed. After calculating the elevation of the top / bottom plate of the left / right centerline, the elevation of the top / bottom plate of the left / right side web is calculated based on the elevation of the top / bottom plate of the left / right centerline.

2. The method for controlling the alignment of a steel box girder according to claim 1, characterized in that: in, Elevation difference to the left of the bridge / road centerline: H 左 =△L 左 *i 左 ; Elevation difference to the right of the bridge / road centerline: H 右 =△L 右 *i 右 In the formula H 左 / 右 This refers to the elevation difference between the left and right sides of the bridge / road centerline. △L 左 / 右 The width of the bridge on the left / right side of the road centerline; i 左 / 右 This refers to the slope values ​​on the left and right sides of the bridge / road centerline. The calculation of the preset pre-arch value is as follows: Y1 = a1X1² + b1X1 + c1; Where: Y1—Design camber value for each axis; X1 — Distance of each axis from the origin; a1, b1, c1 — constant values; Workshop camber value calculation: In the formula: Y2—design camber value for each axis; X2 — the distance of each axis from the origin; a2, b2, c2 — constant values; The calculation method for step A2 is: X 左 / 右 =X0+△Z / YL0*sinθ Y 左 / 右 =Y0+△Z / YL0*cosθ In the formula X 左 / 右 The X-coordinate values ​​of the left / right side web contours; The Y-coordinate value of the left / right side web profile; This represents the Y-coordinate of the road centerline. X0 is the X-coordinate value of the road centerline; △Z / YL0 is the distance between the left / right web and the center line of the road; θ is the angle between the normal and the perpendicular; The method for calculating the bridge deck elevation of the road centerline is as follows: H0=H i +△H In the formula, H0 represents the bridge deck elevation along the road centerline. H i —Design theoretical elevation; △H—Total camber value; The method for calculating the top surface elevation of the top slab and the bottom surface elevation of the top slab of the road centerline using its data is as follows: H 0顶1 =H0-P; H 0顶2 =H 0顶1 -T i . In the formula H 0顶1 —Elevation of the top surface of the slab above the road centerline; H0—Bridge deck elevation along the road centerline; P—Thickness of the paving layer; H 0顶2 —Elevation of the top and bottom surfaces of the road centerline; Ti – Top plate thickness; The method for determining the top / bottom elevation of the top plate of the left / right box girder centerline is as follows: ZFH 0顶1 =H 0顶1 -△ZFL0*i1; YFH 0顶1 =H 0顶1 +△YFL0*i2; Z / YFH 0顶2 =Z / YFH 0顶1 -T i . In the formula ZFH 0顶1 —Elevation of the top surface of the top plate along the centerline of the left box girder; △ZFL0——Distance between the centerline of the left box girder and the centerline of the road; i1 — Slope value of the left transverse slope; YFH 0顶1 —Elevation of the top surface of the top plate along the centerline of the right-side box girder; i2 — Slope value of the right-side cross slope; △YFL0—Distance between the centerline of the right box girder and the centerline of the road; Z / YFH 0顶2 —Elevation of the top surface of the centerline of the left / right box girder; After calculating the change in web beam height, the elevation of the bottom plate along the left / right centerline is calculated as follows: Z / YFH 0底1 =Z / YFH 0顶2 -△FL0; Z / YFH 0底2 =Z / YFH 0底1 -D i . In the formula Z / YFH 0底1 —Elevation of the top surface of the bottom plate along the left / right centerline; △FL0—Change in web beam height; Z / YFH 0底2 —Elevation of the bottom surface of the left / right centerline plate; D i —Base plate thickness; The elevations of the top and bottom plates of the left and right side webs are calculated based on the elevations of the top and bottom plates of the left and right centerlines, as follows: ZFBH 顶1 =ZFH 0顶1 -△ZFBL0*i1; YFBH 顶1 =YFH 0顶1 +△YFBL0*i2; Z / YFBH 顶2 =Z / YFBH 顶1 -T i ; Z / YFBH 底1 =Z / YFBH 顶2 -△FL0; Z / YFBH 底2 =Z / YFBH 底1 -D i . In the formula ZFBH 顶1 —Elevation of the top surface of the top plate of the left side web; △ZFBL0——The distance from the left side web to the left centerline web; YFBH 顶1 —Elevation of the top surface of the right side web; △YFBL0——The distance from the right side web to the right centerline web; Z / YFBH 顶2 —Elevation of the top and bottom surfaces of the left / right side webs; Z / YFBH 底1 —Elevation of the top surface of the bottom plate of the left / right side web; Z / YFBH 底2 —Elevation of the bottom surface of the left / right side web plate.

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