Parametric modeling and drawing method of simply supported U-type aqueduct structure based on BIM

Abstract

The application discloses a kind of parameterized modeling mapping methods of simple-supported U-type aqueduct structure based on BIM in the technical field of hydraulic engineering three-dimensional modeling, mainly by being based on traditional BIM modeling technology, by the basic physical unit such as point, line, surface, body of aqueduct structure is parameterized, parameterized construction model, prestressed steel tendon model and steel bar model are established, can view structure arrangement, steel tendon arrangement and steel bar arrangement from three-dimensional angle, and view the relative position relationship of three, then can form section view by establishing section plane, utilize front view, side view, section cutting and so on Function arranges drawing according to specified order, forms the technical rule with automatic mapping function.Subsequently, when modeling is carried out to the aqueduct structure of the same type and different size, only the corresponding parameters need to be modified, the modeling and drawing of the aqueduct can be completed, which greatly facilitates the design work, and also simplifies the design difficulty of construction measures with the construction party, so that the forward design of the aqueduct is realized.

Description

Technical Field

[0001] This invention relates to the field of three-dimensional modeling technology for water conservancy projects, and in particular to a parametric modeling and mapping method for a simply supported U-shaped aqueduct structure based on BIM. Background Technology

[0002] Building Information Modeling (BIM) is a digital technology-based building information management method that aims to achieve information integration and sharing throughout the entire lifecycle of a building project, from design and construction to operation and maintenance, by creating and managing 3D models of the project. In recent years, water conservancy projects have gradually begun to adopt BIM technology; however, its application in water conservancy projects is still relatively shallow, especially for prestressed concrete aqueduct structures. Often, only 3D structural design and external shape viewing are performed, without the development of specific modeling techniques. This makes it difficult to achieve forward design of aqueducts, especially given the diverse types of reinforcing steel used in their construction.

[0003] Simply supported U-shaped aqueducts are a type of spatial long-shell thin-walled aqueduct structure, characterized by excellent stress distribution, favorable hydraulic conditions, and small engineering volume, thus enjoying widespread application. Current 3D drawing methods for aqueducts are common to concrete structures and have general applicability; however, they have the following drawbacks when drawing this specific type of spatial thin-walled long-shell structure:

[0004] (1) Drawings can only be produced step by step according to the general drawing method for concrete structures, which is a lot of work;

[0005] (2) The drawings cannot be drawn together with the prestressed steel strands; additional drawings related to the prestressed steel strands will be required later.

[0006] (3) Design documents often need to be modified repeatedly. After drawing with this method, the front view, side view and section view cannot be updated in a linked manner.

[0007] Therefore, it is necessary to study a more efficient and forward-design-friendly method for aqueduct modeling and mapping. Summary of the Invention

[0008] To overcome the shortcomings of existing concrete structure drawing methods, such as large drawing workload, inability to display prestressed steel strands, and inability to update drawings, the technical problem to be solved by this invention is to provide a parametric modeling and drawing method for simply supported U-shaped aqueduct structures based on BIM that can improve drawing efficiency and facilitate modification.

[0009] The technical solution adopted by this invention to solve its technical problem is:

[0010] A BIM-based parametric modeling and mapping method for simply supported U-shaped aqueduct structures includes the following steps:

[0011] S1. Determine the dimensions that meet the hydraulic conditions of the aqueduct according to the project requirements, including the longitudinal and transverse dimensions of the aqueduct body, as well as the location and type of prestressed steel strands and reinforcing bars;

[0012] S2. Establish local coordinate systems in the main coordinate system corresponding to the changes in the cross-section of the tank body. All local coordinate systems are aligned with the main coordinate system.

[0013] S3. Based on the dimensions of the aqueduct, first draw a sketch on the cross section perpendicular to the longitudinal direction of the aqueduct at the location where the local coordinate system is established, and parameterize the shape and size on the cross section to obtain the transverse parameters. Then, according to the location of the change in the cross section of the aqueduct, obtain the longitudinal parameters. Finally, based on the transverse and longitudinal parameters, establish a three-dimensional structural model template in the BIM software.

[0014] S4. Establish the coordinate points of the start and end points of the steel strands in two local coordinate systems and connect them into a straight line to establish the longitudinal prestressed steel strand line. Complete the establishment of the longitudinal prestressed steel strands sequentially to form a longitudinal prestressed steel strand group, and assign a number and diameter attribute to each longitudinal prestressed steel strand. Offset the inner wall's water-facing direction to the outside of the aqueduct to obtain an offset surface. Intersect the offset surface with a plane perpendicular to the aqueduct's centerline to obtain the shape of the circumferential prestressed steel strand. Extend both ends upwards by a certain distance to generate circumferential prestressed steel strands. Move and replicate the circumferential prestressed steel strands along the length of the aqueduct on the offset surface to obtain a circumferential prestressed steel strand group, and assign a number and diameter attribute to each circumferential prestressed steel strand. Establish a parameterized prestressed steel strand model template based on the longitudinal and circumferential prestressed steel strand groups.

[0015] S5. Select one or more surfaces from the 3D construction model template to form a surface group. Set the protective layer thickness as c, the diameter of the first layer of reinforcing bars near the surface as d1, and the diameter of the second layer of reinforcing bars as d2. Offset the selected surface or surface group inward along its normal direction by c + 0.5d1 to obtain the first offset surface. Intersect the first offset surface with a plane perpendicular to it to obtain the preliminary shape of the circumferential reinforcing bars. Extend both ends upwards and bend them into hooks to generate circumferential reinforcing bars. Move and copy the circumferential reinforcing bars on the first offset surface to obtain a circumferential reinforcing bar group. Assign the circumferential reinforcing bar type and diameter attributes. Offset the selected surface or surface group inward along its normal direction by c + d1 + 0.5d2 to obtain the second offset surface. Intersect the second offset surface with a horizontal plane to obtain the preliminary shape of the longitudinal reinforcing bars. Move and copy the longitudinal reinforcing bars on the offset surface along its tangential direction to obtain a longitudinal reinforcing bar group. Assign the longitudinal reinforcing bar type and diameter attributes. Establish a parametric reinforcing bar model template based on the longitudinal and circumferential reinforcing bar groups.

[0016] S6. Select the location where the groove body needs to be cut, and obtain the parameterized cutting surface by establishing the coordinates of the four points of the cutting surface in the local coordinate system;

[0017] S7. According to the drawing program of the BIM software, call the three-dimensional structural model template, the prestressed steel strand model template and the rebar model template in sequence. At the same time, according to the longitudinal dimension, transverse dimension of the trough body, the position and type of the prestressed steel strands and rebars determined in S1, input each parameter into the corresponding template to generate the three-dimensional structural drawing of the aqueduct. Then call the cutting program of the software, input the cutting surface parameters, and generate the trough body layout drawing, the prestressed steel strand layout drawing and the rebar layout drawing.

[0018] Furthermore, the lateral parameters include: inner side axle width B1, standard section wall thickness B2, standard section outer side axle width B3, standard section outer side straight wall section height H1, water-facing inner wall straight wall section height H2, axle height H3, tie rod height H4, water-facing arc radius R0, trough body outer wall arc radius R1, standard section bottom thickened area height H0, standard section bottom length L1, end rib bottom thickened area height H5, end rib outer side straight wall section height H6, end rib bottom length L2, and waterstop groove width B4.

[0019] Furthermore, the longitudinal parameters include: total length of the trench body W1, length of the transition section W2, length of the end rib W3, length of the post-cast strip W4, length of the waterstop groove W5, width of the tie rod W6, spacing of the tie rods W7, and whether a tie rod is installed at the mid-span position.

[0020] Furthermore, when constructing a 3D model template using BIM software in S3, the following steps are included:

[0021] S31. Using the plane generation command, based on the longitudinal parameters, establish the starting plane of the aqueduct, the ending plane of the waterstop, the dividing plane of the post-cast strip, the starting plane of the transition section, the ending plane of the transition section, and the mid-span plane.

[0022] S32. Using the sketch command, draw the sketch of the aqueduct end rib and the aqueduct end rib waterstop groove on the starting plane of the aqueduct, draw the sketch of the transition section on the starting plane of the transition section, and draw the sketch of the standard section on the ending plane of the transition section.

[0023] S33. Extrude the end rib sketch and the standard segment sketch using the extrude command to generate the end rib model and the standard segment model. Extrude the end rib model to the starting plane of the transition segment and the standard segment model to the mid-span plane. Connect the transition segment sketch and the standard segment sketch using the multi-section envelope command to generate the transition segment model.

[0024] S34. Using the sketch command, draw a sketch of the tie rod section on the mid-span plane. Using the extrude command, generate a tie rod model at the center position. By setting the formula, when the parameter "whether to set tie rod at mid-span position" is 1, the tie rod is located at the mid-span. When the parameter is 0, the center of the tie rod is W7 / 2 distance from the mid-span plane. The total length of the groove W1 is applied in the formula settings. Using the array command, according to the tie rod spacing parameter, array the tie rod models to obtain the center tie rod and the end tie rod.

[0025] S35. By adding the command, the end rib model, the transition segment model, the standard segment model, the center tie rod, and the end tie rod are combined into a whole half-span model.

[0026] S36. First, use the extrude command to extrude the waterstop groove sketch to create the waterstop groove model. Then, use the subtract command to subtract the waterstop groove from the overall half-span model.

[0027] S37. Draw a sketch of the end circumferential second-stage anchor concrete at the starting plane of the aqueduct, and draw a sketch of the middle circumferential second-stage anchor concrete at the mid-span section. Use the extrude command to extrude the end circumferential second-stage anchor concrete sketch and the middle circumferential second-stage anchor concrete sketch to create the end circumferential second-stage anchor concrete model and the half-span middle circumferential second-stage anchor concrete model. Use the subtract command to subtract the end circumferential second-stage anchor concrete model and the half-span middle circumferential second-stage anchor concrete model from the overall half-span model to obtain the concrete half-span model. Then use the split command to divide the concrete half-span model into the post-cast strip model and the first-stage concrete half-span model.

[0028] S38. Using the mirror command, mirror the post-cast strip model, the first-stage concrete half-span model, and the circumferential second-stage sealing anchor concrete model in the mid-span plane. Then, using the add command, combine the two half-span models into a concrete model. Merge the circumferential second-stage sealing anchor concrete models in the middle of the two connected half-spans into a middle circumferential second-stage sealing anchor concrete model. This completes the establishment of the structural model template.

[0029] Furthermore, when creating a prestressed steel strand model template in S4 using BIM software, the following steps are included: creating a steel strand model using RebarSmart, using the fixed-distance reinforcement function, first selecting the reinforcement plane, then selecting the reinforcement guide line, and finally setting the first segment distance, the end segment distance, the steel strand spacing, the steel strand extension, the steel strand type, and the steel strand diameter to generate the steel strand.

[0030] Furthermore, in S5, a rebar model template is created using RebarSmart. Through the fixed-distance rebar placement function, the rebar plane is first selected, then the rebar guide line is selected, and finally the first segment distance of the interval, the end distance of the interval, the rebar extension and hook, the rebar type and the rebar diameter are set to generate the rebar.

[0031] Furthermore, when extending and bending the prestressed steel strands and reinforcing bars in S4 and S5, the locations of each line segment are calculated according to the following principle:

[0032] S51. Initial line segment AB, starting coordinates are... The endpoint coordinates are ,

[0033] Obtain the direction vector of AB ,in ;

[0034] S52. First, extend BC by a length L1 to obtain the endpoint. ;

[0035] S53. The hook needs to be generated in a plane perpendicular to the straight line. Select the normal direction vector of the hook plane. ;

[0036] S54. Calculate the center of the hook. ;

[0037] S55. Generate the hook, the parametric equation of which is: ,

[0038] Hook end point , and These are two mutually perpendicular unit vectors located in the plane of the hook;

[0039] Where the center is O, the radius is R, the starting angle is 0°, the ending angle is α, and β represents the rotation angle of a point on the arc relative to the starting edge;

[0040] S56. Directional vector after the second extended hook Extend distance L2, extend endpoint .

[0041] Furthermore, when generating the trench layout drawing, prestressed steel strand layout drawing, and rebar layout drawing in S7, the drawing layout is first performed. The drawing layout of the aqueduct is as follows: trench structure drawing, prestressed steel strand layout drawing, and rebar layout drawing. All three types of drawings are arranged in the order of elevation layout and cross-sectional layout. Then, the viewport layout is performed according to the required drawing size. Each viewport layout is customized. The layout method is to project the model from the front and top, or to cut the model to obtain the sectioned structure. Finally, the projection is dimensioned, and the quantity of trench engineering, prestressed steel strand engineering, and rebar engineering is calculated using the engineering quantity table. After that, the printing parameters can be designed and the drawings are generated.

[0042] The beneficial effects of this invention are as follows: Based on traditional BIM modeling technology, by parameterizing the basic physical units of the aqueduct structure, such as points, lines, surfaces, and volumes, a parameterized structural model, prestressed steel strand model, and rebar model can be established. The structural layout, steel strand layout, and rebar layout can be viewed from a three-dimensional perspective, and their relative positional relationships can be observed. By establishing sectional planes to form sectional views, and using functions such as front view, side view, and sectioning to arrange drawings in a specified order, a technical rule with automated drawing functions is formed. For subsequent aqueduct structures of this type, only parameters need to be modified to complete the aqueduct modeling and drawing, which greatly facilitates the design work and also realizes the forward design of this type of structure. Attached Figure Description

[0043] Figure 1 This is a flowchart of the present invention;

[0044] Figure 2 This is the front view of the three-dimensional structural model of the aqueduct;

[0045] Figure 3 This is a top view of the three-dimensional structural model of the aqueduct;

[0046] Figure 4 This is a side view of the three-dimensional structural model of the aqueduct;

[0047] Figure 5 yes Figure 2 Sectional view (I-I);

[0048] Figure 6 This is a sectional view of the prestressed steel strand model;

[0049] Figure 7 This is a sectional view of the reinforcing steel model;

[0050] Figure 8 This is a schematic diagram showing the locations of steel strands, rebar extensions, and hooks.

[0051] The diagram is labeled as follows: 1-End rib model, 2-Standard section model, 3-Gradual transition section model, 4-Central tie rod, 5-End tie rod, 6-Waterstop groove model, 7-End circumferential secondary sealing and anchoring concrete model, 8-Half-span intermediate circumferential secondary sealing and anchoring concrete model, 9-Longitudinal prestressed steel strand, 10-Circumferential prestressed steel strand, 11-Longitudinal reinforcement, 12-Circumferential reinforcement, 13-Longitudinal steel strand duct. Detailed Implementation

[0052] The invention will be further described below with reference to the accompanying drawings.

[0053] like Figure 1 As shown, the parametric modeling and mapping method for a simply supported U-shaped aqueduct structure based on BIM provided by this invention mainly includes the following steps:

[0054] S1. Based on the project requirements, the structural dimensions of the aqueduct should be initially determined. The structural design calculation should be carried out using the finite element method to determine the dimensions that meet the hydraulic conditions of the aqueduct, including the longitudinal and transverse dimensions of the aqueduct body, as well as the location and type of prestressed steel strands and reinforcing bars.

[0055] S2. Establish a local coordinate system in the main coordinate system corresponding to the position of the change in the cross section of the tank body. All local coordinate systems are in the same direction as the main coordinate system. The change in the length direction of the tank body can be located directly through the local coordinate system. By changing the position of the local coordinate system, the length of the tank body can be updated.

[0056] S3. Based on the dimensions of the aqueduct, first draw a sketch on the cross section perpendicular to the longitudinal direction of the aqueduct at the location where the local coordinate system is established. That is, draw the shape of the cross section at each location of the local coordinate system and parameterize the shape and size on the cross section to obtain the transverse parameters. Then, according to the location of the change in the cross section of the aqueduct, obtain the longitudinal parameters. Finally, based on the transverse and longitudinal parameters, establish a three-dimensional structural model template in the BIM software.

[0057] S4. Establish the coordinate points of the start and end points of the steel strands in two local coordinate systems and connect them into a straight line to establish the longitudinal prestressed steel strand line. Complete the establishment of the longitudinal prestressed steel strands sequentially to form a longitudinal prestressed steel strand group, and assign a number and diameter attribute to each longitudinal prestressed steel strand. Offset the inner wall's water-facing direction to the outside of the aqueduct to obtain an offset surface. Intersect the offset surface with a plane perpendicular to the aqueduct's centerline to obtain the shape of the circumferential prestressed steel strand. Extend both ends upwards by a certain distance to generate circumferential prestressed steel strands. Move and replicate the circumferential prestressed steel strands along the length of the aqueduct on the offset surface to obtain a circumferential prestressed steel strand group, and assign a number and diameter attribute to each circumferential prestressed steel strand. Establish a parameterized prestressed steel strand model template based on the longitudinal and circumferential prestressed steel strand groups.

[0058] S5. Select one or more surfaces from the 3D construction model template to form a surface group. Set the protective layer thickness as c, the diameter of the first layer of reinforcing bars near the surface as d1, and the diameter of the second layer of reinforcing bars as d2. Offset the selected surface or surface group inward along its normal direction by c + 0.5d1 to obtain the first offset surface. Intersect the first offset surface with a plane perpendicular to it to obtain the preliminary shape of the circumferential reinforcing bars. Extend both ends upwards and bend them into hooks to generate circumferential reinforcing bars. Move and copy the circumferential reinforcing bars on the first offset surface to obtain a circumferential reinforcing bar group. Assign the circumferential reinforcing bar type and diameter attributes. Offset the selected surface or surface group inward along its normal direction by c + d1 + 0.5d2 to obtain the second offset surface. Intersect the second offset surface with a horizontal plane to obtain the preliminary shape of the longitudinal reinforcing bars. Move and copy the longitudinal reinforcing bars on the offset surface along its tangential direction to obtain a longitudinal reinforcing bar group. Assign the longitudinal reinforcing bar type and diameter attributes. Establish a parametric reinforcing bar model template based on the longitudinal and circumferential reinforcing bar groups.

[0059] S6. Select the location where the groove body needs to be cut, and obtain the parameterized cutting surface by establishing the coordinates of the four points of the cutting surface in the local coordinate system;

[0060] S7. According to the drawing program of the BIM software, call the three-dimensional structural model template, the prestressed steel strand model template and the rebar model template in sequence. At the same time, according to the longitudinal dimension, transverse dimension of the trough body, the position and type of the prestressed steel strands and rebars determined in S1, input each parameter into the corresponding template to generate the three-dimensional structural drawing of the aqueduct. Then call the cutting program of the software, input the cutting surface parameters, and generate the trough body layout drawing, the prestressed steel strand layout drawing and the rebar layout drawing.

[0061] The main concept of this invention is to first model an aqueduct with a certain span and cross-section, then parameterize the model dimensions, and subsequently update the model by changing the parameters to obtain aqueduct models with other spans and cross-sections. The dimensions of the aqueduct are mainly composed of transverse and longitudinal parameters, where the transverse parameters are as follows: Figure 4 , Figure 5 As shown, the parameters include: inner axle width B1, standard section wall thickness B2, standard section outer axle width B3, standard section outer straight wall section height H1, water-facing inner straight wall section height H2, axle height H3, tie rod height H4, water-facing arc radius R0, trench outer wall arc radius R1, standard section bottom thickened area height H0, standard section bottom length L1, end rib bottom thickened area height H5, end rib outer straight wall section height H6, end rib bottom length L2, and waterstop groove width B4. Longitudinal parameters are as follows: Figure 2 , Figure 3 As shown, it includes: total length of the groove body W1, length of the transition section W2, length of the end rib W3, length of the post-pouring strip W4, length of the waterstop groove W5, width of the tie rod W6, spacing of the tie rods W7, and whether a tie rod is installed at the mid-span position.

[0062] Specifically, when constructing a 3D model template using BIM software, such as Figure 2-5 As shown, the following steps can be followed:

[0063] S31. Using the plane generation command, based on the longitudinal parameters, establish the starting plane of the aqueduct, the ending plane of the waterstop, the dividing plane of the post-cast strip, the starting plane of the transition section, the ending plane of the transition section, and the mid-span plane.

[0064] S32. Using the sketch command, draw the sketch of the aqueduct end rib and the aqueduct end rib waterstop groove on the starting plane of the aqueduct, draw the sketch of the transition section on the starting plane of the transition section, and draw the sketch of the standard section on the ending plane of the transition section.

[0065] S33. Extrude the end rib sketch and the standard segment sketch using the extrude command to generate end rib model 1 and standard segment model 2. Extrude end rib model 1 to the starting plane of the transition segment and standard segment model 2 to the mid-span plane. Connect the transition segment sketch and the standard segment sketch using the multi-section envelope command to generate transition segment model 3.

[0066] S34. Using the sketch command, draw a sketch of the tie rod section on the mid-span plane. Using the extrude command, generate the tie rod model at the center position. By setting the formula, when the parameter "whether to set tie rod at mid-span position" is 1, the tie rod is located at the mid-span. When the parameter is 0, the center of the tie rod is W7 / 2 distance from the mid-span plane. The total length of the groove W1 is applied in the formula setting. Using the array command, according to the tie rod spacing parameter, array the tie rod model to obtain the center tie rod 4 and the end tie rod 5.

[0067] S35. By adding the command, combine the end rib model 1, the transition segment model 3, the standard segment model 2, the center tie rod 4, and the end tie rod 5 into a whole half-span model.

[0068] S36. First, use the stretch command to stretch the waterstop groove sketch to create waterstop groove model 6. Then, use the subtract command to subtract the waterstop groove model from the overall half-span model.

[0069] S37. Draw a sketch of the end circumferential second-stage anchor concrete at the starting plane of the aqueduct, and draw a sketch of the middle circumferential second-stage anchor concrete at the mid-span section. Use the extrude command to extrude the end circumferential second-stage anchor concrete sketch and the middle circumferential second-stage anchor concrete sketch to create end circumferential second-stage anchor concrete model 7 and half-span middle circumferential second-stage anchor concrete model 8. Use the subtract command to subtract end circumferential second-stage anchor concrete model 7 and half-span middle circumferential second-stage anchor concrete model 8 from the overall half-span model to obtain the concrete half-span model. Then use the split command to divide the concrete half-span model into the post-cast strip model and the first-stage concrete half-span model.

[0070] S38. Using the mirror command, mirror the post-cast strip model, the first-stage concrete half-span model, and the end circumferential second-stage sealing anchor concrete model 7 in the mid-span plane. Then, using the add command, combine the two half-span models into a concrete model. Merge the two connected half-span intermediate circumferential second-stage sealing anchor concrete models 8 into an intermediate circumferential second-stage sealing anchor concrete model. This completes the establishment of the structural model template.

[0071] When creating a prestressed tendon model template using BIM software, the following steps can be followed: Create the tendon model using RebarSmart. Using the spacing reinforcement function, first select the reinforcement plane, then select the reinforcement guide line, and finally set the first segment distance, end segment distance, tendon spacing, tendon extension, tendon type, and tendon diameter to generate the tendons. When creating the rebar model template, use the same method as the prestressed tendon model: create the rebar model using RebarSmart. Using the spacing reinforcement function, first select the reinforcement plane, then select the reinforcement guide line, and finally set the first segment distance, end segment distance, rebar extension and hooks, rebar type, and rebar diameter to generate the rebar. The final sectional views of the prestressed tendon model template and the rebar model template are shown below. Figure 6 , Figure 7 As shown.

[0072] Furthermore, when extending and bending the prestressed steel strands and reinforcing bars in S4 and S5, such as Figure 8 As shown, the positions of each line segment are calculated according to the following principle:

[0073] S51. Initial line segment AB, starting coordinates are... The endpoint coordinates are ,

[0074] Obtain the direction vector of AB ,in ;

[0075] S52. First, extend BC by a length L1 to obtain the endpoint. ;

[0076] S53. The hook needs to be generated in a plane perpendicular to the straight line. Select the normal direction vector of the hook plane. ;

[0077] S54. Calculate the center of the hook. ;

[0078] S55. Generate the hook, the parametric equation of which is: ,

[0079] Hook end point , and These are two mutually perpendicular unit vectors located in the plane of the hook;

[0080] Where the center is O, the radius is R, the starting angle is 0°, the ending angle is α, and β represents the rotation angle of a point on the arc relative to the starting edge;

[0081] S56. Directional vector after the second extended hook Extend distance L2, extend endpoint .

[0082] After determining the coordinates of each point and the length of each line segment by following the above steps, you can draw a sketch to generate prestressed steel strands and reinforcing bars.

[0083] When generating the final layout drawings of the aqueduct, prestressed steel strands, and reinforcement, the existing BIM software programs are called sequentially according to the following process: First, the drawings are laid out. The aqueduct drawings are laid out in the following order: the aqueduct structure drawing, the prestressed steel strands layout drawing, and the reinforcement layout drawing. All three types of drawings are arranged in the order of elevation and cross-section layout. Then, the viewport layout is set according to the required drawing size. Each viewport layout is customized. The layout method is to project the model from the front and top, or to cut the model to obtain the sectioned structure. Finally, the projection is dimensioned, and the quantities of the aqueduct, prestressed steel strands, and reinforcement are calculated using the quantity table.

[0084] To easily distinguish between prestressed tendons and reinforcing bars, the reinforcing bars can be hidden when generating the prestressed tendon layout drawing, and the prestressed tendons can be hidden when generating the reinforcing bar layout drawing, resulting in the following: Figure 6 The sectional view of the prestressed steel strand model shown and Figure 7 The sectional view of the reinforcing steel model shown. Figure 6 As shown, the circumferential prestressed steel strand group closest to the cutting plane is projected onto the cutting plane to generate the circumferential prestressed steel strand 10; the longitudinal prestressed steel strand group perpendicular to the cutting plane intersects the cutting plane at a series of points, which are displayed as solid points with diameter attributes on the cutting plane, namely the longitudinal prestressed steel strand 9. Figure 7 As shown, the circumferential reinforcement group closest to the cutting plane is projected onto the cutting plane to generate circumferential reinforcement 12. The longitudinal reinforcement group perpendicular to the cutting plane intersects the cutting plane at a series of points. This point is displayed as a solid point with diameter attribute on the cutting plane, which is the longitudinal reinforcement 11. For the convenience of subsequent construction, the cutting point of the prestressed steel strand is usually shown in the sectional view of the reinforcement. The longitudinal steel strand duct 13 can be represented by a circle, indicating that there is a prestressed duct passing through this point.

[0085] After the drawing is completed, printing parameters can be set according to the text content, line color, etc. The printing parameters mainly reflect the characteristics of distinguishing between primary and secondary elements. In the trench body construction drawing, the solid lines of the construction are thickened. In the trench body steel strand layout drawing, the steel strands are the main representation, that is, the steel strand lines and dots are displayed in thickened form, while the trench body construction does not need to be thickened. In the trench body reinforcement layout drawing, the reinforcement is the main representation, that is, the reinforcement lines and dots are displayed in thickened form, while the trench body construction and steel strands do not need to be thickened. This is to facilitate the output of drawings required by designers, and can be exported as CAD or PDF files.

[0086] When structural adjustments are needed later, longitudinal and transverse parameters, as well as the type and diameter of prestressed steel strands and reinforcing bars, can be changed, and the model will automatically update accordingly. After the update, by using the "Update Current Drawing" command in the drawing interface, the front view, side view, and section view can be updated to obtain new versions of the aqueduct structure drawing, prestressed steel strand layout drawing, and reinforcing bar layout drawing, greatly improving design efficiency. In addition, parameterizing the model enables collaborative design. If there are simply supported aqueduct structures of different sizes, an aqueduct model can be created first, and the corresponding reinforcement can be completed. By adjusting and updating the structural model through parameterization, and then updating the reinforcing bar model, the reinforcement of another shape of aqueduct can be achieved. The model can then be delivered to the construction team, who can directly use the 3D model to design construction schemes, greatly simplifying the complexity and difficulty of construction measure design.

Claims

1. A parametric modeling and mapping method for simply supported U-shaped aqueduct structures based on BIM, characterized in that, Includes the following steps: S1. Determine the dimensions that meet the hydraulic conditions of the aqueduct according to the project requirements, including the longitudinal and transverse dimensions of the aqueduct body, as well as the location and type of prestressed steel strands and reinforcing bars; S2. Establish local coordinate systems in the main coordinate system corresponding to the changes in the cross-section of the tank body. All local coordinate systems are aligned with the main coordinate system. S3. Based on the dimensions of the aqueduct, first draw a sketch on the cross section perpendicular to the longitudinal direction of the aqueduct at the location where the local coordinate system is established, and parameterize the shape and size on the cross section to obtain the transverse parameters. Then, according to the location of the change in the cross section of the aqueduct, obtain the longitudinal parameters. Finally, based on the transverse and longitudinal parameters, establish a three-dimensional structural model template in the BIM software. S4. Establish the coordinate points of the start and end points of the steel strands in two local coordinate systems and connect them into a straight line to establish the longitudinal prestressed steel strand line. Complete the establishment of the longitudinal prestressed steel strands sequentially to form a longitudinal prestressed steel strand group, and assign a number and diameter attribute to each longitudinal prestressed steel strand. Offset the inner wall's water-facing direction to the outside of the aqueduct to obtain an offset surface. Intersect the offset surface with a plane perpendicular to the aqueduct's centerline to obtain the shape of the circumferential prestressed steel strand. Extend both ends upwards by a certain distance to generate circumferential prestressed steel strands. Move and replicate the circumferential prestressed steel strands along the length of the aqueduct on the offset surface to obtain a circumferential prestressed steel strand group, and assign a number and diameter attribute to each circumferential prestressed steel strand. Establish a parameterized prestressed steel strand model template based on the longitudinal and circumferential prestressed steel strand groups. S5. Select one or more surfaces from the 3D construction model template to form a surface group. Set the protective layer thickness as c, the diameter of the first layer of reinforcing bars near the surface as d1, and the diameter of the second layer of reinforcing bars as d2. Offset the selected surface or surface group inward along its normal direction by c + 0.5d1 to obtain the first offset surface. Intersect the first offset surface with a plane perpendicular to it to obtain the preliminary shape of the circumferential reinforcing bars. Extend both ends upwards and bend them into hooks to generate circumferential reinforcing bars. Move and copy the circumferential reinforcing bars on the first offset surface to obtain a circumferential reinforcing bar group, and assign the circumferential reinforcing bar type and diameter attributes. Offset the selected surface or surface group inward along its normal direction by c + d1 + 0.5d2 to obtain the second offset surface. Intersect the second offset surface with a horizontal plane to obtain the preliminary shape of the longitudinal reinforcing bars. Move and copy the longitudinal reinforcing bars on the offset surface along its tangential direction to obtain a longitudinal reinforcing bar group, and assign the longitudinal reinforcing bar type and diameter attributes. Establish a parametric reinforcing bar model template based on the longitudinal and circumferential reinforcing bar groups. S6. Select the location where the groove body needs to be cut, and obtain the parameterized cutting surface by establishing the coordinates of the four points of the cutting surface in the local coordinate system; S7. According to the drawing program of the BIM software, call the three-dimensional structural model template, the prestressed steel strand model template and the rebar model template in sequence. At the same time, according to the longitudinal dimension, transverse dimension of the trough body, the position and type of the prestressed steel strands and rebars determined in S1, input each parameter into the corresponding template to generate the three-dimensional structural drawing of the aqueduct. Then call the cutting program of the software, input the cutting surface parameters, and generate the trough body layout drawing, the prestressed steel strand layout drawing and the rebar layout drawing.

2. The parametric modeling and mapping method for a simply supported U-shaped aqueduct structure based on BIM as described in claim 1, characterized in that, The lateral parameters include: inner side axle width B1, standard section wall thickness B2, standard section outer side axle width B3, standard section outer side straight wall section height H1, water-facing inner wall straight wall section height H2, axle height H3, tie rod height H4, water-facing arc radius R0, trench body outer wall arc radius R1, standard section bottom thickened area height H0, standard section bottom length L1, end rib bottom thickened area height H5, end rib outer side straight wall section height H6, end rib bottom length L2, and waterstop groove width B4.

3. The parametric modeling and mapping method for a simply supported U-shaped aqueduct structure based on BIM as described in claim 2, characterized in that, The longitudinal parameters include: total length of the trench body W1, length of the transition section W2, length of the end rib W3, length of the post-cast strip W4, length of the waterstop groove W5, width of the tie rod W6, spacing of the tie rods W7, and whether a tie rod is installed at the mid-span position.

4. The parametric modeling and mapping method for a simply supported U-shaped aqueduct structure based on BIM as described in claim 3, characterized in that, When constructing a 3D model template using BIM software in S3, the following steps are included: S31. Using the plane generation command, based on the longitudinal parameters, establish the starting plane of the aqueduct, the ending plane of the waterstop, the dividing plane of the post-cast strip, the starting plane of the transition section, the ending plane of the transition section, and the mid-span plane. S32. Using the sketch command, draw the sketch of the aqueduct end rib and the aqueduct end rib waterstop groove on the starting plane of the aqueduct, draw the sketch of the transition section on the starting plane of the transition section, and draw the sketch of the standard section on the ending plane of the transition section. S33. Extrude the end rib sketch and the standard segment sketch using the extrude command to generate the end rib model and the standard segment model. Extrude the end rib model to the starting plane of the transition segment and the standard segment model to the mid-span plane. Connect the transition segment sketch and the standard segment sketch using the multi-section envelope command to generate the transition segment model. S34. Using the sketch command, draw a sketch of the tie rod section on the mid-span plane. Using the extrude command, generate a tie rod model at the center position. By setting the formula, when the parameter "whether to set tie rod at mid-span position" is 1, the tie rod is located at the mid-span. When the parameter is 0, the center of the tie rod is W7 / 2 distance from the mid-span plane. The total length of the groove W1 is applied in the formula settings. Using the array command, according to the tie rod spacing parameter, array the tie rod models to obtain the center tie rod and the end tie rod. S35. By adding the command, the end rib model, the transition segment model, the standard segment model, the center tie rod, and the end tie rod are combined into a whole half-span model. S36. First, use the extrude command to extrude the waterstop groove sketch to create the waterstop groove model. Then, use the subtract command to subtract the waterstop groove model from the overall half-span model. S37. Draw a sketch of the end circumferential second-stage anchor concrete at the starting plane of the aqueduct, and draw a sketch of the middle circumferential second-stage anchor concrete at the mid-span section. Use the extrude command to extrude the end circumferential second-stage anchor concrete sketch and the middle circumferential second-stage anchor concrete sketch to create the end circumferential second-stage anchor concrete model and the half-span middle circumferential second-stage anchor concrete model. Use the subtract command to subtract the end circumferential second-stage anchor concrete model and the half-span middle circumferential second-stage anchor concrete model from the overall half-span model to obtain the concrete half-span model. Then use the split command to divide the concrete half-span model into the post-cast strip model and the first-stage concrete half-span model. S38. Using the mirror command, mirror the post-cast strip model, the first-stage concrete half-span model, and the circumferential second-stage sealing anchor concrete model in the mid-span plane. Then, using the add command, combine the two half-span models into a concrete model. Merge the circumferential second-stage sealing anchor concrete models in the middle of the two connected half-spans into a middle circumferential second-stage sealing anchor concrete model. This completes the establishment of the structural model template.

5. The parametric modeling and mapping method for a simply supported U-shaped aqueduct structure based on BIM as described in claim 1, characterized in that, When creating a prestressed steel strand model template in S4 using BIM software, the following steps are included: create a steel strand model using RebarSmart, use the fixed-distance reinforcement function to first select the reinforcement plane, then select the reinforcement guide line, and finally set the first segment distance of the interval, the end distance of the interval, the steel strand spacing, the steel strand extension, the steel strand type and the steel strand diameter to generate the steel strand.

6. The parametric modeling and mapping method for a simply supported U-shaped aqueduct structure based on BIM as described in claim 1, characterized in that, In S5, a rebar model template is created using RebarSmart. Using the fixed-distance rebar placement function, first select the rebar placement plane, then select the rebar placement guide line, and finally set the first segment distance of the interval, the end distance of the interval, the rebar extension and hook, the rebar type and the rebar diameter to generate the rebar.

7. The parametric modeling and mapping method for a simply supported U-shaped aqueduct structure based on BIM as described in claim 1, characterized in that, When extending and bending prestressed steel strands and reinforcing bars in S4 and S5, the locations of each line segment are calculated according to the following principle: S51. Initial line segment AB, starting coordinates are... The endpoint coordinates are , Obtain the direction vector of AB ,in ; S52. First, extend BC by a length L1 to obtain the endpoint. ; S53. The hook needs to be generated in a plane perpendicular to the straight line. Select the normal direction vector of the hook plane. ; S54. Calculate the center of the hook. ; S55. Generate the hook, the parametric equation of which is: , Hook end point , and These are two mutually perpendicular unit vectors located in the plane of the hook; Where the center is O, the radius is R, the starting angle is 0°, the ending angle is α, and β represents the rotation angle of a point on the arc relative to the starting edge; S56. Direction vector after the second extended hook Extend distance L2, extend endpoint .

8. The parametric modeling and mapping method for a simply supported U-shaped aqueduct structure based on BIM as described in claim 1, characterized in that, When generating the aqueduct layout, prestressed steel strand layout, and reinforcement layout in S7, the first step is to lay out the drawings. The aqueduct's drawing layout is as follows: the aqueduct structure drawing, the prestressed steel strand layout drawing, and the reinforcement layout drawing. All three types of drawings are arranged in order of elevation and cross-section. Then, the viewport layout is set according to the required drawing size. Each viewport layout is customized by projecting the model from the front and top, or by cutting the model to obtain the sectioned structure. Finally, the projection is dimensioned, and the quantities of the aqueduct, prestressed steel strands, and reinforcement are calculated using the quantity table. After that, the printing parameters can be designed to generate the drawings.

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