A forward design method for bridge towers based on BIM technology

Abstract

The present invention discloses a forward design method for bridge towers based on BIM technology. The present invention uses a non-parametric method to construct a three-dimensional model of the bridge tower, fits the three-dimensional model to obtain the three-dimensional parameters of the three-dimensional model of the bridge tower, establishes a BIM model according to the three-dimensional parameters, parallelly establishes a finite element model according to the BIM model, analyzes the finite element model, optimizes the finite element model according to the analysis results, and generates construction drawings of the bridge tower according to the optimized finite element model, solving the problems of slow design speed, poor design quality, and cumbersome and repeated modification in the existing bridge tower design. And by introducing BIM technology into the forward design of bridge towers, a mature, reliable and efficient method is provided for the forward design of bridge towers, solving the technical problem that it is difficult to apply BIM technology to the design of bridge towers in the prior art.

Description

Technical Field

[0001] The present invention relates to the field of auxiliary design of bridge towers, and particularly to a forward design method of bridge towers based on BIM technology. Background Art

[0002] BIM (Building Information Model) is an engineering data model based on three-dimensional information technology, integrating various relevant information of engineering projects. And the project model information can be stored, transmitted and shared throughout the whole life cycle from the early stage of project planning, design, construction to the later operation. The intuitiveness, collaboration, virtualization of the BIM model and the flow of data information throughout the whole process of the project make the BIM technology gradually replace the traditional two-dimensional modeling technology. In the domestic and foreign construction industries, especially in complex single buildings, the BIM technology has been applied to a certain extent. However, in the field of civil infrastructure such as bridge towers and railways, the application of the BIM technology is relatively lagging behind.

[0003] Complex shapes often pose great challenges to structural design. Especially in the landscape conceptual design stage of bridge towers, the contour of the shape is often not a simple arc or a curve that can be expressed by parameters, but a gradually changing or spline curve. Moreover, in order to pursue the beauty of the spatial shape, it is often designed as a spatial surface, which is formed by sweeping or bonding in three-dimensional drawing software in the conceptual design stage and is difficult to form a parametric expression. This has caused certain obstacles and resistance to the application of BIM technology in bridge tower projects, especially in the three-dimensional design of bridge towers.

[0004] Therefore, it is urgent for the staff in this field to provide a forward design method of bridge towers based on BIM technology. Summary of the Invention

[0005] The present invention provides a forward design method of bridge towers based on BIM technology to solve the technical problem that it is difficult to apply the BIM technology to the design of bridge towers in the prior art.

[0006] To solve the above technical problem, the technical solution proposed by the present invention is: a forward design method of bridge towers based on BIM technology, including:

[0007] Constructing a three-dimensional model of the bridge tower using a non-parametric method;

[0008] Fitting the three-dimensional model to obtain the three-dimensional parameters of the three-dimensional model of the bridge tower;

[0009] Establishing a BIM model according to the three-dimensional parameters;

[0010] Parallelly establishing a finite element model according to the BIM model, analyzing the finite element model, and optimizing the finite element model according to the analysis results;

[0011] Generate the construction drawings of the bridge tower based on the optimized finite element model.

[0012] Preferably, fitting the 3D model to obtain the 3D parameters of the 3D model includes the following steps:

[0013] Slice the space surface of the 3D model vertically at regular intervals to obtain multiple cross-sections and the curves of the outer contours of the cross-sections;

[0014] Use the curve fitting method to fit multiple curves to obtain the 3D parameters of multiple curves;

[0015] Combine the 3D parameters of multiple curves to obtain the 3D parameters of the 3D model.

[0016] Preferably, using the curve fitting method to fit the curve includes the following steps:

[0017] Take the curve as the first curve, divide the first curve into multiple second curves, use circular arcs to fit the second curves to obtain the 2D parameters of the second curves, and splice the 2D parameters of multiple second curves to obtain the 2D parameters of the first curve.

[0018] Preferably, establishing a finite element model parallel to the BIM model includes: dividing the finite element model into elements to obtain a discrete finite element model.

[0019] Preferably, analyzing the finite element model and optimizing the finite element model according to the analysis results includes: simulating the construction of the bridge tower and performing a load analysis on the discrete finite element model, and optimizing the structure of the discrete finite element model according to the results of the load analysis until the results of the load analysis meet the design requirements.

[0020] The present invention has the following beneficial effects:

[0021] 1. The present invention uses a non-parametric method to construct a 3D model of the bridge tower, fits the 3D model to obtain the 3D parameters of the 3D model of the bridge tower, establishes a BIM model according to the 3D parameters, establishes a finite element model parallel to the BIM model, analyzes the finite element model, optimizes the structural dimensions according to the analysis results until the bridge tower calculation passes, and generates the construction drawings of the bridge tower according to the optimized BIM model, solving the problems of slow design speed, poor design quality, and cumbersome and repeated modification in the existing bridge tower design.

[0022] 2. The present invention introduces the BIM technology into the forward design of the bridge tower, providing a mature, reliable and efficient method for the forward design of the bridge tower, and solving the technical problem that it is difficult to apply the BIM technology to the bridge tower design (especially the bridge tower with high landscape requirements) in the existing technology.

[0023] In addition to the purposes, features and advantages described above, the present invention has other purposes, features and advantages. The following will refer to the accompanying drawings to further elaborate on the present invention in detail. Description of the Drawings

[0024] The drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0025] Figure 1 is a flowchart of the forward design method of the bridge tower based on BIM technology in the preferred embodiment of the present invention;

[0026] Figure 2 is a schematic diagram of the first curve in the preferred embodiment of the present invention;

[0027] Figure 3 is a partially enlarged schematic diagram of the first curve in the preferred embodiment of the present invention. Detailed Embodiments

[0028] The following will elaborate on the embodiments of the present invention in detail with reference to the accompanying drawings. However, the present invention can be implemented in many different ways defined and covered by the claims.

[0029] See Figure 1 , a forward design method of a bridge tower based on BIM technology of the present invention includes:

[0030] S1 Construct a three-dimensional model of the bridge tower using a non-parametric method;

[0031] S2 Fit the three-dimensional model to obtain the three-dimensional parameters of the three-dimensional model of the bridge tower;

[0032] S3 Establish a BIM model based on the three-dimensional parameters;

[0033] S4 Parallelly establish a finite element model according to the BIM model, analyze the finite element model, and optimize the finite element model according to the analysis results;

[0034] S5 Generate construction drawings of the bridge tower according to the optimized BIM model.

[0035] It should be noted that constructing a three-dimensional model of the bridge tower using a non-parametric method includes obtaining the three-dimensional model of the bridge tower by means of stretching, bonding, etc. using three-dimensional software. At this time, the three-dimensional parameters of the three-dimensional model of the bridge tower are unknown. Therefore, it is necessary to fit the contour of the three-dimensional model to obtain the three-dimensional parameters of the three-dimensional model of the bridge tower, establish a BIM model of the bridge tower based on the three-dimensional parameters of the bridge tower, analyze the finite element model, optimize the finite element model according to the analysis results, optimize the structural dimensions until the finite element analysis calculation results of the bridge tower pass, and generate construction drawings of the bridge tower according to the optimized BIM model.

[0036] In addition, the analysis of the finite element model of the pylon includes the static analysis of the local part of the finite element model of the pylon, that is, the tensile stress and compressive stress analysis, and also includes the static analysis of the whole finite element model of the pylon.

[0037] Optionally, fitting the three-dimensional model to obtain the three-dimensional parameters of the three-dimensional model includes the following steps:

[0038] Slice the space surface of the three-dimensional model vertically at regular intervals to obtain multiple cross-sections and the curves of the outer contours of the cross-sections;

[0039] Use the curve fitting method to fit multiple curves to obtain the three-dimensional parameters of multiple curves;

[0040] Combine the three-dimensional parameters of multiple curves to obtain the three-dimensional parameters of the three-dimensional model.

[0041] It should be noted that slicing the space surface of the three-dimensional model vertically at regular intervals to obtain multiple cross-sections and the curves of the outer contours of the cross-sections, the set distance determines the accuracy of the slicing and also determines the smoothness of the transition of the space surface of the three-dimensional model.

[0042] Optionally, using the curve fitting method to fit the curve includes the following steps:

[0043] Take the curve as the first curve, divide the first curve into multiple segments of second curves, use circular arcs to fit multiple segments of second curves to obtain the two-dimensional parameters of the second curves, and splice the two-dimensional parameters of multiple segments of second curves to obtain the two-dimensional parameters of the first curve.

[0044] In this optional embodiment, divide the first curve into multiple segments of second curves, with one endpoint interval between each segment of second curves, set a limit angle θ, and the endpoints satisfy both of the following two items: (1) The included angles between the two tangents at the two endpoints of any one segment of second curve and the line connecting the two endpoints of the second curve are both less than the limit angle θ; (2) When there are corner points (turning points) on the first curve, take the corner points as endpoints.

[0045] See Figures 2 - 3 , using the curve fitting method to fit the curve specifically includes:

[0046] S101 Divide the first curve A into n - 1 segments, and the endpoint sequences in order are A1, A2, A3, …, An (where the starting endpoint is A1 and the ending endpoint is An), to obtain multiple segments of second curve sequences A1A2, A2A3, …, An - 1An;

[0047] When using an arc to fit the first of the second curves in the first curve: At the endpoint A1, draw a perpendicular to the tangent of the first second curve A1A2 as the first radial line L1 of the second curve A1A2. Connect the endpoints A1 and A2, draw the perpendicular bisector Lc1 of the line segment A1A2, obtain the intersection of the perpendicular bisector Lc1 of the line segment A1A2 and the first radial line L1, and use it as the center C1 of the second curve A1A2. Figure 3 (Not shown in), connect the endpoint A2 and the center C1 as the second radial line L2 of the second curve A1A2 (according to geometric relationships, the lengths of the radial line L1 and the line segment L2 are the same), and the center of the arc used to fit the second curve A1A2 is C1 and the radius is the radial line L1, that is, the two-dimensional parameters of the first second curve are obtained.

[0048] When using an arc to fit the second to n - 1 second curves (n > 2) in the first curve: For any second curve, connect the two endpoints of the second curve to draw a perpendicular bisector. The center of the arc used to fit the second curve is the intersection of the perpendicular bisector and the second radial line of the previous second curve, and the radius is the connection between the intersection and the endpoint of the second curve, that is, the two-dimensional parameters of the second curve are obtained.

[0049] S104 splice the two-dimensional parameters of the first second curve and the two-dimensional parameters of the second to n - 1 second curves (n > 2) to obtain the two-dimensional parameters of the first curve.

[0050] Optionally, establishing a finite element model parallel to the BIM model includes: dividing the finite element model into elements to obtain a discrete finite element model.

[0051] In this optional embodiment, use Midas FEA software to establish a finite element model of the bridge tower, import the BIM model into Midas FEA software to divide elements, and obtain a structurally discrete finite element model. The structurally discrete finite element model includes: pile cap, lower tower column, lower decorative block, cross beam, upper tower column, upper decorative block, tower crown, tower column isolation plate.

[0052] Optionally, analyze the finite element model and optimize the finite element model according to the analysis results, including: simulating the construction stage of the bridge tower, performing a load analysis on the discrete finite element model, and optimizing the structure of the discrete finite element model according to the results of the load analysis until the results of the load analysis meet the design requirements.

[0053] It should be noted that analyzing the finite element model includes performing a load analysis after applying loads to the finite element model. The loads include one or more of the following combinations: self-weight of the structure, prestress, reaction force, cable force, longitudinal wind, and transverse wind.

[0054] In this alternative embodiment, the analysis of the finite element model includes: defining material properties, load cases, boundary conditions, solver parameters, etc. The load analysis of the discrete finite element model according to the construction stages of the bridge tower includes one or more combinations of the following principal stress analyses:

[0055] Conduct a principal stress analysis on the cross beam, lower tower column, and lower decorative block as a whole in the first construction stage;

[0056] Conduct a principal stress analysis on the lower decorative block in the second construction stage; conduct a principal stress analysis on the cross beam in the second construction stage; conduct a principal stress analysis on the tower column diaphragm in the second construction stage; conduct a principal stress analysis on the upper tower column and upper decorative block in the second construction stage; conduct a principal stress analysis on the tower crown in the second construction stage;

[0057] Conduct a principal stress analysis on the lower decorative block in the third construction stage; conduct a principal stress analysis on the cross beam in the third construction stage; conduct a principal stress analysis on the tower column diaphragm in the third construction stage; conduct a principal stress analysis on the upper tower column and upper decorative block in the third construction stage; conduct a principal stress analysis on the tower crown in the third construction stage.

[0058] In a specific embodiment, the load analysis of the discrete finite element model is carried out according to the construction stages of the bridge tower, where:

[0059] The first construction stage:

[0060] 1) Conduct a principal stress analysis on the cross beam, lower tower column, and lower decorative block as a whole: The principal tensile stresses of the cross beam are all small, and it is basically in a compressive state. In the same plane, a larger concrete compressive stress appears in the prestressed anchorage area than in other positions. This is mainly because the method used in simulating the prestress is to couple a node with the concrete, and it is inevitable that stress distortion occurs. In actual situations, due to the existence of the anchor plate under the anchor, the stress should be much smaller than the calculated value;

[0061] The second construction stage:

[0062] 1) Conduct a principal stress analysis on the lower decorative block: The principal tensile stresses of the decorative block are all small, and there is no risk of cracking;

[0063] 2) Conduct a principal stress analysis on the cross beam: Except for a little concentration of node stress transfer at the cutting interface of the tower crown structure, the principal tensile stress and principal compressive stress of the tower crown are both small, and there is no risk of cracking;

[0064] 3) Conduct a principal stress analysis on the tower column diaphragm: The principal tensile stresses are all small, mainly in compression, and there is no risk of cracking;

[0065] 4) Conduct a principal stress analysis on the upper tower column and upper decorative block: The maximum tensile stress is at the lower edge of the upper tower column decoration, but it is still less than 1.89 MPa, and there is no risk of cracking;

[0066] 5) Perform the principal stress analysis on the tower crown: Except for a little stress concentration at the structural cutting interface, the principal tensile stress and principal compressive stress of the tower crown are both small, and there is no risk of cracking.

[0067] The third construction stage:

[0068] 1) Perform the principal stress analysis on the lower decorative block: Under the action of unbalanced loads, the lower decorative block is also in a state of one side being compressed and the other side being tensioned. The maximum principal tensile stress is about 3 MPa, and the main tensile stress direction is the transverse direction of the bridge. By querying the stresses of each individual load, under the action of self-weight, the maximum principal tensile stress at the top of the lower decorative block reaches 1.4 MPa; under the action of cable force, the maximum principal tensile stress at the top of the lower decorative block reaches 1.8 MPa; under the action of longitudinal wind, the maximum principal tensile stress at the top of the lower decorative block reaches 0.2 MPa; under other loads, the maximum principal tensile stress at the top of the lower decorative block is relatively small. By analyzing the principal tensile stress of the lower decorative block under each individual load, it can be known that the lower decorative block should be constructed after the entire bridge tower is poured and the stay cables are tensioned, which can greatly optimize the stress of the lower decorative block.

[0069] 2) Perform the principal stress analysis on the cross beam: The principal tensile stresses of the cross beam are all small, and it is basically in a compressed state.

[0070] 3) Perform the principal stress analysis on the cross diaphragms of the tower column: The principal tensile stresses of some nodes of the cross diaphragms of the tower column are relatively large, less than 1.89 MPa. It can be seen from the principal compressive stress nephogram that under the action of unbalanced cable forces and longitudinal wind, the tower column is in an eccentric compression state in the longitudinal direction of the bridge, and the maximum principal compressive stress is less than the designed compressive strength value of 24.4 MPa.

[0071] 4) Perform the principal stress analysis on the upper tower column and the upper decorative block: The lower edge of the upper decorative block is basically in a compressed state. In the second construction stage, all bridge tower units have been activated, and the loads activate the self-weight and the prestress of the cross beam. It can be seen that the top of the lower decorative block of the bridge tower is in tension, and the maximum principal tensile stress is 1.26 MPa, which does not reach the cracking stress. In the third construction stage, on the basis of the second construction stage, the loads activate the cable force, longitudinal wind, transverse wind, and reaction force. It can be seen that the principal tensile stress at the top of the lower decorative block of the bridge tower is very small, and there is a principal compressive stress of 1.3 MPa. The upper decorative block changes from being mainly in tension to being mainly in compression. It can be seen that the action of the cable force will make the decorative block in compression, which is beneficial to the stress of the decorative block. Therefore, the upper decorative block should be poured before the stay cables are tensioned. There is a stress concentration phenomenon at the stay cable position, and this calculation can ignore the stress exceeding the standard at this place.

[0072] 5) Perform the principal stress analysis on the tower crown: The principal tensile stresses of the crown diaphragm are all small except at the manhole position. There is stress concentration at the manhole position, and a steel frame is set in the structural design to strengthen the diaphragm, and there is no overall risk of cracking.

[0073] In a specific embodiment, the discrete finite element model structure is optimized according to the results of the load analysis until the results of the load analysis meet the design requirements, including: for the parts with excessive stress, adjusting the structural wall thickness accordingly, or configuring more steel bars when establishing the finite element model, making the tower columns of the bridge tower more "substantial" and capable of withstanding more loads.

[0074] In this alternative embodiment, an overall finite element model is established in parallel with the BIM model, the overall finite element model is subjected to load analysis, and the overall and / or discrete finite element models are optimized according to the analysis results.

[0075] Compare the load analysis results of the discrete finite element model with those of the overall finite element model: Except for the stress concentration phenomenon, the extreme values of the load analysis results of the discrete finite element model appear near the upper part of the cross beam, which is consistent with the load analysis results of the overall finite element model.

[0076] In summary, the present invention first constructs a three-dimensional model of the bridge tower using a non-parametric method, fits the three-dimensional model to obtain the three-dimensional parameters of the bridge tower three-dimensional model, then establishes a BIM model according to the three-dimensional parameters, establishes a finite element model in parallel with the BIM model, analyzes the finite element model, optimizes the finite element model according to the analysis results, and finally generates the construction drawings of the bridge tower according to the optimized finite element model, solving the problems of slow design speed, poor design quality, and cumbersome design process with repeated modifications in the existing bridge tower design. And introducing the BIM technology into the forward design of the bridge tower provides a mature, reliable, and efficient method for the forward design of the bridge tower, solving the technical problem that it is difficult to apply the BIM technology to the bridge tower design in the existing technology.

[0077] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example.

[0078] Any process or method description shown in the flowchart or described in other ways herein can be understood as representing a module, segment, or part of code including one or more executable instructions for implementing a specific logical function or process, and the scope of the preferred embodiments of the present invention includes additional implementations, where the functions can be executed in a substantially simultaneous manner or in the reverse order according to the involved functions, rather than in the order shown or discussed, which should be understood by those skilled in the art to which the embodiments of the present invention belong.

[0079] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A forward design method for bridge towers based on BIM technology, characterized in that, Including: Constructing a three-dimensional model of the bridge tower using a non-parametric method; Fitting the three-dimensional model to obtain the three-dimensional parameters of the three-dimensional model of the bridge tower; Fitting the three-dimensional model to obtain the three-dimensional parameters of the three-dimensional model includes the following steps: Cut the space surface of the three-dimensional model vertically at regular intervals to obtain a plurality of cross-sections and the curves of the outer contours of the cross-sections; Using a curve fitting method to fit the plurality of curves to obtain the three-dimensional parameters of the plurality of curves; Using a curve fitting method to fit the curves includes the following steps: Taking the curve as the first curve, dividing the first curve into multiple second curves, fitting the second curves with circular arcs to obtain the two-dimensional parameters of the second curves, and splicing the two-dimensional parameters of the multiple second curves to obtain the two-dimensional parameters of the first curve; The using circular arcs to fit the second curves includes: making a first perpendicular line to the tangent at the first endpoint of the first segment of the second curve, connecting the first endpoint and the second endpoint to obtain a connecting line, making a perpendicular bisector based on the connecting line, taking the intersection of the perpendicular bisector and the first perpendicular line as the center of the second curve, connecting the center and the second endpoint to obtain a second perpendicular line, and taking the length from the center to the first endpoint or the second endpoint as the radius; Connecting the first endpoint and the second endpoint of the nth segment of the second curve of other segments to obtain a connecting line, making a perpendicular bisector based on the connecting line, taking the intersection of the perpendicular bisector of the nth segment of the second curve and the second perpendicular line of the (n - 1)th segment of the second curve as the center of the nth segment of the second curve, and taking the length from the center of the nth segment of the second curve to the first endpoint or the second endpoint as the radius; Splicing the three-dimensional parameters of the plurality of curves to obtain the three-dimensional parameters of the three-dimensional model; Establishing a BIM model according to the three-dimensional parameters; Parallelly establishing a finite element model according to the BIM model, analyzing the finite element model, and optimizing the finite element model according to the analysis results; Generating construction drawings of the bridge tower according to the optimized finite element model.

2. The forward design method for bridge towers based on BIM technology according to claim 1, characterized in that, Parallelly establishing a finite element model according to the BIM model includes: performing element division on the finite element model to obtain a discrete finite element model.

3. The forward design method for bridge towers based on BIM technology according to claim 2, characterized in that, Analyzing the finite element model and optimizing the finite element model according to the analysis results includes: simulating the construction of the bridge tower and performing load analysis on the discrete finite element model, and optimizing the structure of the discrete finite element model according to the results of the load analysis until the results of the load analysis meet the design requirements.

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