Parametric modeling method and system for steel box girder of footbridge

Abstract

The present application relates to a kind of footbridge steel box girder parameterized modeling method and system.The existing parameterized modeling method cannot adapt to irregular boundary, and it is not consistent with the positive design concept, and it is difficult and complex.This method obtains first base line according to the plane design curve of footbridge steel box girder;Top plate, top plate stiffener, bottom plate and bottom plate stiffener are generated, side plate and side plate stiffener are generated, web and web stiffener are generated, transverse diaphragm is generated, and model with longitudinal section parameter is obtained by integration;With plane design curve as target curve, with first base line as base curve, obtain footbridge steel box girder model.The present application is mainly based on linear bridge parameterized modeling command, can complete complex curve bridge parameterized modeling, can adapt to the design of irregular boundary;It can be dynamically modified, consistent with the concept of positive design, simplify the modeling process, greatly reduce the difficulty and complexity of modeling.

Description

Technical Field

[0001] This invention relates to the field of bridge engineering technology, specifically to a parametric modeling method and system for steel box girders of pedestrian overpasses. Background Technology

[0002] Pedestrian overpasses are a common urban transportation facility, providing safe and convenient passageways for pedestrians. Pedestrian overpasses come in various structural forms, with steel box girders being a frequently used type due to their lightweight, aesthetic appeal, and durability. A steel box girder consists of a top plate, bottom plate, side plates, web plates, and transverse diaphragms, all connected by welding. The design and construction of steel box girders require consideration of various factors, such as geometric dimensions, longitudinal slope, transverse slope, and reinforcing ribs, all of which affect the load-bearing capacity and appearance of the steel box girder.

[0003] Existing steel box girder pedestrian bridges often have irregular cross-sections, planes, or sides due to landscape design requirements, resulting in variations in the dimensions and shape of the cross-sections at different locations. Current design methods are cumbersome, requiring extensive repetitive work, and prone to errors. They also lack the ability to dynamically modify dimensions or intuitively assess problems in the drawings. Currently, steel box girder design can be achieved through modeling. There are two main modeling methods: one is a solid-based, non-parametric modeling method, where a cross-sectional view of the steel box girder is first drawn, and then a 3D solid model is generated through operations such as extrusion or scanning. This method is not suitable for complex shapes. The other is a parametric modeling method, where various parameters of the steel box girder are defined according to the bridge's characteristics, and then a 3D solid model is automatically generated through programming or software tools. In comparison, the parametric modeling method offers higher efficiency and flexibility, allowing for rapid modification and optimization of the steel box girder.

[0004] However, existing parametric modeling methods for steel box girders still have some shortcomings: the parametric modeling methods are relatively simple and cannot adapt to steel box girders with irregular edges; moreover, most parametric methods still require modeling based on the designed cross-section, which is inconsistent with the concept of forward design; in addition, directly performing operations such as lofting and scanning based on the actual design curve increases the difficulty and complexity of modeling for steel box girders with complex cross-sections.

[0005] Therefore, it is necessary to propose a new parametric modeling method for steel box girders of pedestrian overpasses to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide a parametric modeling method and system for steel box girders of pedestrian overpasses, in order to solve the problems of existing parametric modeling methods, such as inability to adapt to irregular edges, inconsistency with forward design concepts, and high difficulty and complexity.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A parametric modeling method for steel box girders of pedestrian overpasses, the method comprising:

[0009] Based on the planar design curve of the pedestrian overpass steel box girder, the first foundation line is obtained;

[0010] The top plate, top plate stiffening ribs, bottom plate, and bottom plate stiffening ribs are generated using the first basic line.

[0011] Offset the first base line to obtain the second base line, and use the first base line and the second base line to generate the side plate and the side plate stiffening rib;

[0012] A third base line is established between the first and second base lines, and the web and web stiffening ribs are generated using the third base line.

[0013] Determine the first location point on the first base line, and use the first location point to generate the diaphragm;

[0014] By integrating the top plate, top plate stiffening ribs, bottom plate, bottom plate stiffening ribs, side plates, side plate stiffening ribs, web plate, web plate stiffening ribs, and transverse diaphragms, a model with longitudinal section parameters is obtained.

[0015] Determine the second location point on the first base line, and use the second location point to generate the cross-section line;

[0016] Using the planar design curve as the target curve and the first basic line as the base curve, the steel box girder model of the pedestrian overpass is obtained.

[0017] Furthermore, based on the planar design curve of the pedestrian overpass steel box girder, the first foundation line is obtained, including:

[0018] Draw the planar design curve s of the steel box girder of the pedestrian overpass, with a length of L;

[0019] Obtain the length L, construct two points on the X-axis, and construct line segment A′A′ based on the two points;

[0020] Move line segment AA′ along the positive Y-axis to obtain line segment BB′, move line segment AA′ in the negative Z-axis direction to obtain line segment CC′, and move line segment BB′ in the negative Z-axis direction to obtain line segment DD′.

[0021] Divide the line segment AA′ into equal parts to obtain the division points. Use the division points to reconstruct and interpolate to obtain the sine curve m.

[0022] Line segments A′A′, BB′, CC′, DD′, and the sine curve m are the first basic lines.

[0023] Furthermore, the top plate, top plate stiffening ribs, bottom plate, and bottom plate stiffening ribs are generated using the first basic line, including:

[0024] Based on line segments A′A′, BB′, CC′, and DD′, the top and bottom plates are generated through stretching, offsetting, and mirroring operations.

[0025] Connect AB, obtain the division point by dividing AB equally, move the division point, and connect the division point accordingly to obtain the vertical center line of the top plate stiffening rib section, and obtain the top plate stiffening rib by stretching and equidistant solid offset.

[0026] Connect CD, obtain the vertical center line of the bottom plate stiffening rib section by dividing CD into equal parts, moving the equal parts, and connecting the equal parts. Obtain the bottom plate stiffening rib by stretching and offsetting the solid at equal distances.

[0027] Further, a second base line is obtained by offsetting the first base line, and the side plates and side plate stiffening ribs are generated using the first and second base lines, including:

[0028] Offset line segment BB′ outward along the positive Y-axis to obtain line segment EE′ outside the guardrail;

[0029] Lofting is performed using line segments EE′ and DD′ as two lofting edges to generate an inclined plane;

[0030] Shift the sine curve m in the negative Z-axis direction to generate the curve m′;

[0031] Using the inclined plane as the projection plane, the curve m′ is projected along the Y direction to obtain the lower edge line n of the side chamfer.

[0032] Move the lower edge line n of the side chamfer towards the positive Z-axis to generate the upper edge line n′ of the chamfer.

[0033] Line segment EE′, curve m′, and upper edge of the tangent angle n′ are the second basic lines;

[0034] For the first and second base lines, the side plates and side plate stiffening ribs are generated using operations such as lofting, double-track sweeping, pulling back to the surface, stretching, surface combination, and solid offset.

[0035] Furthermore, a third base line is established between the first and second base lines, and the web and web stiffening ribs are generated using the third base line, including:

[0036] Connect AB to obtain line segment AB, which is the third base line;

[0037] Find point P on line segment AB top Find point P on line segment CD. bottom ;

[0038] Connect P top and P bottom Obtain the web line P top P bottom Stretch P along the positive X-axis top P bottom Generate web surface P top P bottom P′ top P′ bottom By offsetting the solid on one side in the positive Y direction to form the web, and using XZ as the mirror plane, two symmetrical webs are generated.

[0039] Obtain the web line P top P bottom Two points P on a P b By moving points and connecting corresponding points, the vertical centerline of the stiffening rib section is obtained. By stretching and equidistant solid offset operations, the web stiffening rib is generated.

[0040] Further, determining a first location point on the first base line and generating a transverse diaphragm using the first location point includes:

[0041] Several points are obtained on line segment AA′, which are the first position points;

[0042] Based on the first position point, draw a line segment parallel to the y-axis and symmetrical about the x-axis, and obtain the outer contour of the middle diaphragm, the outer contour of the side diaphragm, the manhole, the manhole annular boss, and the weld hole through the operation of projection, thickening, Boolean, offset, and positioning.

[0043] Furthermore, by integrating the top plate, top plate stiffeners, bottom plate, bottom plate stiffeners, side plates, side plate stiffeners, web plate, web plate stiffeners, and transverse diaphragms, a model with longitudinal section parameters is obtained, including:

[0044] Integrating top plate, top plate stiffening ribs, bottom plate, bottom plate stiffening ribs, side plates, side plate stiffening ribs, web plate, web plate stiffening ribs, and transverse diaphragms;

[0045] A model with longitudinal section parameters is obtained based on the YOZ plane.

[0046] Furthermore, a second location point is determined on the first base line, and a cross-sectional line is generated using the second location point, including:

[0047] Point P is obtained on line segment AA′, which is the second location point;

[0048] Draw a line segment parallel to the y-axis and symmetrical about the x-axis based on the second position point, and obtain the cross-sectional line through projection.

[0049] Furthermore, using the planar design curve as the target curve and the first basic line as the base curve, the steel box girder model of the pedestrian overpass is obtained, including:

[0050] The target curve is the planar design curve s, and the line segment AA′ is the base curve.

[0051] For models with longitudinal section parameters, a sweeping operation is used to obtain a model of the steel box girder of a pedestrian overpass.

[0052] On the other hand, a parametric modeling system for steel box girders of pedestrian overpasses is provided, the system being used to implement the method, including:

[0053] The first foundation line generation module is used to obtain the first foundation line based on the planar design curve of the pedestrian overpass steel box girder;

[0054] The first component generation module is used to generate the top plate, top plate stiffening ribs, bottom plate and bottom plate stiffening ribs using the first foundation line;

[0055] The second component generation module is used to offset the first base line to obtain the second base line, and to generate the side plate and side plate stiffening ribs using the first base line and the second base line.

[0056] The third component generation module is used to establish a third base line between the first base line and the second base line, and to generate the web and web stiffening ribs using the third base line.

[0057] The fourth component generation module is used to determine the first location point on the first foundation line and generate the transverse diaphragm using the first location point;

[0058] The integration module is used to integrate the top plate, top plate stiffening ribs, bottom plate, bottom plate stiffening ribs, side plates, side plate stiffening ribs, web plate, web plate stiffening ribs, and transverse diaphragms to obtain a model with longitudinal section parameters.

[0059] The section line generation module is used to determine a second location point on the first base line and generate a section line using the second location point.

[0060] The model generation module uses the planar design curve as the target curve and the first basic line as the base curve to obtain the steel box girder model of the pedestrian overpass.

[0061] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0062] This invention provides a parametric modeling method and system for steel box girders of pedestrian overpasses. It mainly uses parametric modeling commands for straight bridges, can complete parametric modeling of complex curved bridges, and can adapt to the design of irregular edges.

[0063] This method constructs a three-dimensional solid model of a steel box girder by setting the plane lines, longitudinal slope, and other relevant parameters. It eliminates the need to draw complex cross-sectional diagrams and allows for dynamic modification of the dimensions of various parts of the steel box girder, dynamic modification of the plane design lines, dynamic modification of the longitudinal slope values, and dynamic modification of the side plate edge curves. This aligns with the concept of forward design and simplifies the modeling process.

[0064] This method displays the three-dimensional shape and cross-section of the steel box girder in real time, which is intuitive. It allows for detailed parameter settings and control of various parts of complex steel box girders, improving the accuracy and flexibility of modeling. It can intelligently generate drawing cross-sections, effectively reducing repetitive work in the design of pedestrian overpass steel box girders, reducing errors, and greatly reducing the difficulty and complexity of modeling. Attached Figure Description

[0065] 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 embodiments can be obtained from these drawings without creative effort.

[0066] Figure 1 This is a structural schematic diagram of the steel box girder of a pedestrian overpass.

[0067] Figure 2 This is a flowchart of the method of the present invention.

[0068] Figure 3 This is a schematic diagram of S103.

[0069] Figure 4 This is a schematic diagram of the S103 end face.

[0070] Figure 5 This is a schematic diagram of S105.

[0071] Figure 6 This is a schematic diagram of S203.

[0072] Figure 7 This is a schematic diagram of the S203 end face.

[0073] Figure 8 This is a schematic diagram of S307.

[0074] Figure 9 This is a schematic diagram of the S307 end face.

[0075] Figure 10 This is a schematic diagram of S404.

[0076] Figure 11 This is a schematic diagram of S502.

[0077] Figure 12 This is a schematic diagram of the S502 end face.

[0078] Figure 13 This is a schematic diagram of S602.

[0079] Figure 14 This is a schematic diagram of S702.

[0080] Figure 15 This is a schematic diagram of the S702 end face.

[0081] Figure 16 This is a schematic diagram of S802. Detailed Implementation

[0082] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0083] It should be noted that similar reference numerals and letters indicate similar items; therefore, once an item is defined in one embodiment, it does not need to be further defined and explained in subsequent embodiments. Furthermore, the terms "comprising" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0084] It should also be noted that although the order of steps is mentioned in the method description, in some cases, steps may be performed in a different order than that described here, and this should not be interpreted as a restriction on the order of steps.

[0085] Furthermore, in the description of this invention, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance. Of course, such terms can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in a sequence other than those illustrated or described herein.

[0086] like Figure 1The pedestrian bridge steel box girder comprises the following parts: top plate, top plate stiffeners, bottom plate, bottom plate stiffeners, side plates, side plate stiffeners, web plate, web plate stiffeners, and transverse diaphragms. Its parametric modeling can be achieved using programming methods such as Grasshopper, GHpython, and Dynamo. The dimensions and shapes of each part can be adjusted according to the corresponding parameters. The planar shape of the pedestrian bridge steel box girder is determined by a planar design curve, which can be an open curve of any shape. The longitudinal slope of the pedestrian bridge steel box girder is achieved using the shear command, which transforms the planar model along a specified direction and angle. The spatial shape of the pedestrian bridge steel box girder is achieved using the flow command, which allows the planar model to flow along the planar design curve.

[0087] Example 1:

[0088] This embodiment provides a parametric modeling method for steel box girders of pedestrian overpasses, such as... Figure 2 The method includes:

[0089] S1: Based on the planar design curve of the pedestrian overpass steel box girder, the first foundation line is obtained. This includes:

[0090] S101: Draw the planar design curve s of the pedestrian overpass steel box girder from CAD or Rhino, with a length of L;

[0091] S102: Obtain the length L, construct two points (0,0,0) and (L,0,0) on the X-axis, and construct line segment A′A′ based on the two points, which can be used as the baseline of the steel box girder later.

[0092] S103: As Figure 3-4 Move line segment AA′ along the positive Y-axis by d. top / 2+O side / sin(θ)+0.015m yields line segment BB′. Moving line segment AA′ h in the negative Z-axis direction yields line segment CC′. Moving line segment BB′ h in the negative Z-axis direction yields line segment DD′; where d top Where is the net width of the top slab, h is the net distance between the top and bottom slabs, and O is the net width of the top slab. side Let θ be the thickness of the side plate, and θ be the angle between the cross-sectional line of the side plate and the y-axis.

[0093] S104: Divide line segment AA′ into equal parts to obtain equal division points, and denote the number of equal divisions as N; analyze the equal division points to obtain their coordinate values, and reconstruct the points using z(x) = h / 4*sin(2*a*pi / L*(xL / (4*a)))-h / 4 (where the x and y coordinate values ​​of each point remain unchanged, and z is a function of x), with parameter a controlling the period of the function, L being the length of the planar design curve, and h being the net distance between the top and bottom plates; connect the reconstructed points sequentially using the interpolation method to form a sine curve m;

[0094] S105: Line segments A′A′, BB′, CC′, DD′, and the sine curve m are the first basic lines, such as... Figure 5 .

[0095] S2: Generate the top plate, top plate stiffening ribs, bottom plate, and bottom plate stiffening ribs using the first base line. Includes:

[0096] S201: Based on line segments A′A′, BB′, CC′, and DD′, generate a top plate and a bottom plate through stretching, offsetting, and mirroring operations. The thickness of the top plate is denoted as O. top The thickness of the base plate is denoted as O. bottom The net width of the top slab is d top The net width of the base plate is d bottom ;

[0097] S202: Connect AB, the length of AB is d. top / 2, by dividing AB into equal parts, obtaining the division points, moving the division points, and connecting the division points, the vertical center line of the top plate stiffening rib section is obtained, and the top plate stiffening rib is obtained by stretching and offsetting the solid at equal distances.

[0098] S203: As Figure 6-7 Connect CD, obtain the vertical center line of the bottom plate stiffening rib section by dividing CD into equal parts, moving the equal parts, and connecting the equal parts. Obtain the bottom plate stiffening rib by stretching and offsetting the solid at equal distances.

[0099] The vertical height of the stiffening rib is denoted as h. l The width of the stiffening rib is denoted as O. l The vertical centerline spacing of the stiffening ribs is denoted as d. l .

[0100] S3: Offset the first base line to obtain the second base line, and use the first and second base lines to generate the side plates and side plate stiffening ribs. Includes:

[0101] S301: Offset line segment BB′ outward along the positive Y-axis by d h Obtain the line segment EE′, d of the outer boundary of the guardrail. h The intersection of OE and DE;

[0102] S302: Loft using line segments EE′ and DD′ as two lofting edges to generate an inclined plane;

[0103] S303: Shift the sine curve m in the negative Z-axis direction to generate curve m′. The shift distance is the height of the tangent plane, denoted as h. q ;

[0104] S304: Using the inclined plane as the projection plane, project the curve m′ along the Y direction to obtain the lower edge line n of the side chamfer.

[0105] S305: Move the lower edge line n of the side chamfer towards the positive Z-axis direction h. q Generate the upper edge line n′ of the chamfer;

[0106] S306: Line segment EE′, curve m′, and upper edge of the tangent angle n′ are the second basic lines;

[0107] S307: For the first and second base lines, use operations such as lofting, double-track sweeping, pull back to surface, extrude, surface combination, and solid offset to generate side plates and side plate stiffening ribs, such as... Figure 8-9 .

[0108] S4: Establish a third base line between the first and second base lines, and use the third base line to generate the web and web stiffening ribs. This includes:

[0109] S401: Connect AB to obtain line segment AB, which is the third base line;

[0110] S402: Find point P on line segment AB top P top The y-coordinate value is y top Find point P on line segment CD. bottom P bottom The y-coordinate value is y bottom ;P top P bottom The percentages at the top and bottom positions are β1 and β2, respectively;

[0111] S403: Connect P top and P bottom Obtain the web line P top P bottom Stretch P along the positive X-axis top P bottom The stretching length is L, and the web surface P is generated. top P bottom P′ top P′ bottom By offsetting the solid on one side in the positive Y direction to form the web, and using XZ as the mirror plane, two symmetrical webs are generated.

[0112] S404: Obtain web line P top P bottom Two points P on a P bBy moving points and connecting corresponding points, the vertical centerline of the stiffening rib section is obtained. Then, through stretching and equidistant solid offset operations, web stiffening ribs are generated. The percentages of the stiffening ribs at their positions on the web are γ1 and γ2, respectively. Figure 10 .

[0113] S5: Determine the first location point on the first base line, and use the first location point to generate the transverse diaphragm. This includes:

[0114] S501: Obtain several points on line segment AA′, which are the first position points; the x-coordinates of these points are x1, x2, x3...x n , where n is the number of diaphragms, and the x-coordinates of these points are the positions of the diaphragms on the plane;

[0115] S502: Draw a line segment parallel to the y-axis and symmetrical about the x-axis based on the first position point, with a length of d. top +2d h The outer contours of the middle diaphragm, the outer contours of the side diaphragms, the manhole, the manhole annular boss, and the weld hole are obtained through projection, thickening, Boolean, offset, and positioning operations.

[0116] The thickness of the diaphragm is O h The length of the manhole in the diaphragm is d. r The height is h r The fillet is R r The thickness of the annular boss is O. t ,like Figure 11-12 .

[0117] S6: Integrating the top plate, top plate stiffeners, bottom plate, bottom plate stiffeners, side plates, side plate stiffeners, web plate, web plate stiffeners, and transverse diaphragms, a model with longitudinal section parameters is obtained. Includes:

[0118] S601: Integrating top plate, top plate stiffening rib, bottom plate, bottom plate stiffening rib, side plate, side plate stiffening rib, web plate, web plate stiffening rib and transverse diaphragm;

[0119] S602: Using the YOZ plane as a reference, use the shear command to obtain a model with longitudinal section parameters.

[0120] z is the height the bridge is raised, and the longitudinal slope is η, z = L * η, as shown Figure 13 .

[0121] S7: Determine the second location point on the first base line, and use the second location point to generate the cross-section line. This includes:

[0122] S701: Obtain point P on line segment AA′, which is the second location point; the x-coordinate value of P is the location of the cross section;

[0123] S702: Draw a line segment parallel to the y-axis and symmetric about the x-axis, with length d, based on the second position point. top +2d h The cross-sectional lines are obtained through projection.

[0124] The x-coordinate of the cross-section point is I, such as Figure 14-15 .

[0125] S8: Using the planar design curve as the target curve and the first base line as the base curve, obtain the steel box girder model of the pedestrian overpass. Includes:

[0126] S801: The target curve is the planar design curve s, and the basic curve is the line segment AA′.

[0127] S802: For models with longitudinal section parameters, a sweep operation is used to obtain the steel box girder model of a pedestrian overpass, such as... Figure 16 .

[0128] This method can construct a three-dimensional solid model of a steel box girder by setting the horizontal line, longitudinal slope, and other relevant parameters, without the need to draw complex cross-sectional diagrams, which conforms to the concept of forward design. It allows for detailed parameter settings and control of various parts of such complex steel box girders, improving the accuracy and flexibility of modeling. It mainly uses parametric modeling commands for straight bridges to complete parametric modeling of complex curved bridges, greatly reducing the difficulty of parametric modeling of this type of bridge.

[0129] This method is applicable not only to visual programming software such as Grasshopper, but also to other parametric modeling secondary development platforms. It is suitable for both pedestrian bridge steel box girders and vehicular bridge steel box girders. The number of web plates involved in the steel box girder can be one, two, or multiple.

[0130] In this method, in addition to drawing or importing the plane lines and longitudinal slopes, the plane lines can also be defined by inputting parameters such as coordinate points, angles, and lengths.

[0131] The curve function involved in this method can be any other suitable curve or straight line, except for the sine function.

[0132] Example 2:

[0133] This embodiment provides a parametric modeling system for steel box girders of pedestrian overpasses. The system is the same as the method in Embodiment 1, including...

[0134] The first foundation line generation module is used to obtain the first foundation line based on the planar design curve of the pedestrian overpass steel box girder, corresponding to S1 in Embodiment 1;

[0135] The first component generation module is used to generate a top plate, a top plate stiffening rib, a bottom plate, and a bottom plate stiffening rib using the first base line, corresponding to S2 in Embodiment 1.

[0136] The second component generation module is used to offset the first base line to obtain the second base line, and to generate side plates and side plate stiffening ribs using the first base line and the second base line, corresponding to S3 in Embodiment 1.

[0137] The third component generation module is used to establish a third base line between the first base line and the second base line, and to generate the web and web stiffening ribs using the third base line, corresponding to S4 in Embodiment 1.

[0138] The fourth component generation module is used to determine the first position point on the first base line and generate the transverse diaphragm using the first position point, corresponding to S5 in Embodiment 1;

[0139] An integration module is used to integrate the top plate, top plate stiffening rib, bottom plate, bottom plate stiffening rib, side plate, side plate stiffening rib, web plate, web plate stiffening rib, and transverse diaphragm to obtain a model with longitudinal section parameters, corresponding to S6 in Example 1.

[0140] The section line generation module is used to determine a second location point on the first base line and generate a section line using the second location point, corresponding to S7 in Embodiment 1.

[0141] The model generation module uses the planar design curve as the target curve and the first basic line as the base curve to obtain the steel box girder model of the pedestrian overpass, corresponding to S8 in Example 1.

[0142] Those skilled in the art will understand that all or part of the functions of the embodiments of the present invention can be implemented by hardware or by computer program. When all or part of the functions in the above embodiments are implemented by computer program, the program can be stored in a computer-readable storage medium, which may include: read-only memory, random access memory, disk, optical disk, hard disk, etc., and the program is executed by a computer to achieve the above functions. For example, the program can be stored in the memory of a device, and when the program in the memory is executed by the processor, all or part of the above functions can be achieved. In addition, when all or part of the functions in the above embodiments are implemented by computer program, the program can also be stored in a storage medium such as a server, another computer, disk, optical disk, flash drive, or portable hard drive, and can be downloaded or copied to the memory of a local device, or the system of the local device can be updated. When the program in the memory is executed by the processor, all or part of the functions in the above embodiments can be achieved.

[0143] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A parametric modeling method for steel box girders of pedestrian overpasses, characterized by: The method includes: Based on the planar design curve of the pedestrian overpass steel box girder, the first foundation line is obtained; The top plate, top plate stiffening ribs, bottom plate, and bottom plate stiffening ribs are generated using the first basic line. Offset the first base line to obtain the second base line, and use the first base line and the second base line to generate the side plate and the side plate stiffening rib; A third base line is established between the first and second base lines, and the web and web stiffening ribs are generated using the third base line. Determine the first location point on the first base line, and use the first location point to generate the diaphragm; By integrating the top plate, top plate stiffeners, bottom plate, bottom plate stiffeners, side plates, side plate stiffeners, web plate, web plate stiffeners, and transverse diaphragms, a model with longitudinal section parameters is obtained. Determine the second location point on the first base line, and use the second location point to generate the cross-section line; Using the planar design curve as the target curve and the first basic line as the base curve, the steel box girder model of the pedestrian overpass is obtained; in: Based on the planar design curve of the pedestrian overpass steel box girder, the first foundation line is obtained, including: Draw the planar design curve s of the steel box girder of the pedestrian overpass, with a length of L; Obtain the length L, construct two points on the X-axis, and construct line segment AA′ based on the two points; Move line segment AA′ along the positive Y-axis to obtain line segment BB′, move line segment AA′ in the negative Z-axis direction to obtain line segment CC′, and move line segment BB′ in the negative Z-axis direction to obtain line segment DD′. Divide the line segment AA′ into equal parts to obtain the division points. Use the division points to reconstruct and interpolate to obtain the sine curve m. Line segments AA′, BB′, CC′, DD′, and the sine curve m are the first basic lines; The top plate, top plate stiffening ribs, bottom plate, and bottom plate stiffening ribs are generated using the first base line, including: Based on line segments AA′, BB′, CC′, and DD′, the top and bottom plates are generated through stretching, offsetting, and mirroring operations. Connect A and B, obtain the division point by dividing line segment AB equally, move the division point, and connect the division point accordingly to obtain the vertical center line of the top plate stiffening rib section, and obtain the top plate stiffening rib by stretching and equidistant solid offset. Connect C and D, obtain the division point by dividing line segment CD equally, move the division point, and connect the division point accordingly to obtain the vertical center line of the bottom plate stiffening rib section, and obtain the bottom plate stiffening rib by stretching and equidistant solid offset.

2. The parametric modeling method for steel box girders of pedestrian overpasses according to claim 1, characterized in that: Offset the first base line to obtain the second base line, and use the first and second base lines to generate the side plates and side plate stiffening ribs, including: Offset line segment BB′ outward along the positive Y-axis to obtain line segment EE′ outside the guardrail; Lofting is performed using line segments EE′ and DD′ as two lofting edges to generate an inclined plane; Shift the sine curve m in the negative Z-axis direction to generate the curve m′; Using the inclined plane as the projection plane, the curve m′ is projected along the Y-axis to obtain the lower edge line n of the side chamfer. Move the lower edge line n of the side chamfer towards the positive Z-axis to generate the upper edge line n′ of the chamfer. Line segment EE′, curve m′, and upper edge of the tangent angle n′ are the second basic lines; For the first and second base lines, the side plates and side plate stiffening ribs are generated using operations such as lofting, double-track sweeping, pulling back to the surface, stretching, surface combination, and solid offset.

3. The parametric modeling method for steel box girders of pedestrian overpasses according to claim 2, characterized in that: A third base line is established between the first and second base lines. The web and web stiffeners are generated using this third base line, including: Connect A and B to obtain line segment AB, which is the third base line; Find point P on line segment AB top Find point P on line segment CD. bottom ; Connect P top and P bottom Obtain the web line P top P bottom Stretch the web line P along the positive X-axis top P bottom Generate web surface P top P bottom P′ top P′ bottom By offsetting the solid to one side in the positive Y-axis direction to form the web, and using the XOZ plane as a mirror plane, two symmetrical webs are generated. Obtain the web line P top P bottom Two points P on a P b By moving points and connecting corresponding points, the vertical centerline of the stiffening rib section is obtained. By stretching and equidistant solid offset operations, the web stiffening rib is generated.

4. The parametric modeling method for steel box girders of pedestrian overpasses according to claim 3, characterized in that: Determine the first location point on the first base line, and use the first location point to generate the transverse diaphragm, including: Several points are obtained on line segment AA′, which are the first position points; Based on the first position point, draw a line segment parallel to the Y-axis and symmetrical about the X-axis, and obtain the outer contour of the middle diaphragm, the outer contour of the side diaphragm, the manhole, the manhole annular boss, and the weld hole through the operation of projection, thickening, Boolean, offset, and positioning.

5. The parametric modeling method for steel box girders of pedestrian overpasses according to claim 4, characterized in that: Integrating the top plate, top plate stiffeners, bottom plate, bottom plate stiffeners, side plates, side plate stiffeners, web plate, web plate stiffeners, and transverse diaphragms, a model with longitudinal section parameters is obtained, including: Integrating top plate, top plate stiffening ribs, bottom plate, bottom plate stiffening ribs, side plates, side plate stiffening ribs, web plate, web plate stiffening ribs, and transverse diaphragms; A model with longitudinal section parameters is obtained based on the YOZ plane.

6. The parametric modeling method for steel box girders of pedestrian overpasses according to claim 5, characterized in that: Determine a second location point on the first base line, and use the second location point to generate a cross-section line, including: Point P is obtained on line segment AA′, which is the second location point; Draw a line segment parallel to the Y-axis and symmetrical about the X-axis based on the second position point, and obtain the cross-sectional line through projection.

7. The parametric modeling method for steel box girders of pedestrian overpasses according to claim 6, characterized in that: Using the planar design curve as the target curve and the first basic line as the base curve, the steel box girder model of the pedestrian overpass is obtained, including: The target curve is the planar design curve s, and the line segment AA′ is the base curve. For models with longitudinal section parameters, a sweeping operation is used to obtain a model of the steel box girder of a pedestrian overpass.

8. A parametric modeling system for steel box girders of pedestrian overpasses, characterized in that: The system is used to implement the method according to any one of claims 1-7, comprising: The first foundation line generation module is used to obtain the first foundation line based on the planar design curve of the pedestrian overpass steel box girder; The first component generation module is used to generate the top plate, top plate stiffening ribs, bottom plate and bottom plate stiffening ribs using the first foundation line; The second component generation module is used to offset the first base line to obtain the second base line, and to generate the side plate and side plate stiffening ribs using the first base line and the second base line. The third component generation module is used to establish a third base line between the first base line and the second base line, and to generate the web and web stiffening ribs using the third base line. The fourth component generation module is used to determine the first location point on the first foundation line and generate the transverse diaphragm using the first location point; The integration module is used to integrate the top plate, top plate stiffening ribs, bottom plate, bottom plate stiffening ribs, side plates, side plate stiffening ribs, web plate, web plate stiffening ribs, and transverse diaphragms to obtain a model with longitudinal section parameters. The section line generation module is used to determine a second location point on the first base line and generate a section line using the second location point. The model generation module uses the planar design curve as the target curve and the first basic line as the base curve to obtain the steel box girder model of the pedestrian overpass.

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