A BIM-based method and system for installing pipes in large spaces

Abstract

This application discloses a BIM-based method and system for large-space pipeline installation, involving pipeline installation: BIM model data is processed into a three-dimensional mesh to generate a meshed spatial model, constructing the pipeline installation space; the load per unit length of the pipeline is calculated based on the pipeline's self-weight and the weight of the medium inside the pipeline, according to physical parameters; dynamic programming is used to optimize the arrangement of supports and hangers; a state transition equation is constructed based on the pipeline's unit length load and a continuous beam model of structural mechanics; based on the state transition equation, the optimal decision sequence is obtained through reverse recursion, backtracking from the pipeline end to the starting point, and at each decision stage, the support point position that minimizes the cumulative deflection of all subsequent pipe segments is selected, generating a globally optimal support and hanger arrangement sequence; based on the globally optimal support and hanger arrangement sequence and the pipeline's unit length load, the deflection value of each pipe segment is calculated; this application avoids the problem of uneven deflection distribution caused by traditional local optimization methods.

Description

Technical Field

[0001] This application relates to the field of pipe installation, and in particular to a BIM-based method and system for large-space pipe installation. Background Technology

[0002] With the trend towards larger and more complex modern architecture, large-space buildings such as airport terminals, high-speed rail stations, convention centers, and stadiums are increasingly common. These buildings are characterized by large spans, high ceilings, and complex structural forms, posing numerous challenges to the design and installation of their electromechanical piping systems. Piping systems in large-space buildings typically involve multiple disciplines, including water supply and drainage, HVAC, and fire sprinkler systems. The pipes are large in diameter and travel long distances, with single pipes reaching tens or even hundreds of meters in length. During the installation of piping in large spaces, the proper arrangement of supports and hangers is crucial to ensuring the safe and reliable operation of the piping system. Supports and hangers must not only bear the weight of the pipes and the medium but also consider the thermal expansion and contraction effects caused by temperature changes. An unreasonable arrangement of supports and hangers can lead to excessive pipe deflection, affecting pipe slope and fluid transport, and in severe cases, even causing stress concentration, joint leaks, and other safety hazards.

[0003] Traditional pipe support and hanger layout methods rely heavily on designers' experience, employing fixed spacing or referencing recommended values ​​from design manuals. This approach has several drawbacks: Fixed spacing fails to adequately account for uneven pipe load distribution and structural constraints, potentially leading to deflections exceeding allowable limits in certain pipe sections and impacting normal pipe functionality. Experience-based layouts are often overly conservative, with excessively dense supports in areas of low deflection and insufficient support in critical areas, resulting in material waste and unreasonable stress distribution. Large open-plan buildings experience significant temperature variations, leading to substantial thermal expansion and contraction of pipes, making it difficult to accurately calculate the impact of temperature deformation on pipe deflection using traditional methods. Furthermore, traditional methods typically employ localized adjustments, failing to optimize support and hanger layout from a global perspective and thus unable to guarantee the overall optimal solution.

[0004] In recent years, although some scholars have proposed optimization methods for pipe supports and hangers, most of them are limited to simple working conditions or idealized models, making it difficult to handle the complex spatial constraints and multi-objective optimization problems in large-space buildings. At the same time, existing methods lack precise consideration of temperature effects and fail to fully utilize BIM technology to achieve design-construction integration.

[0005] Therefore, there is an urgent need for a new method that can comprehensively consider multiple factors such as load distribution, spatial constraints, and temperature effects, and achieve global optimization of support and hanger layout based on a BIM platform, in order to solve the problem of deflection control in the installation of long-distance pipelines in large spaces. Summary of the Invention

[0006] To address the issue that traditional fixed-spacing or experience-based layouts can lead to excessive deflection in local pipe sections during the installation of long-distance pipelines in large spaces, this application provides a BIM-based method and system for large-space pipeline installation. By transforming the pipeline support and hanger layout problem into a three-dimensional spatial path optimization problem, a dynamic programming algorithm is used to solve for the globally optimal support point sequence under the constraints of deflection and spacing. Furthermore, a pre-supply height compensation curve is generated by combining temperature effects, thus avoiding the problem of uneven deflection distribution caused by traditional local optimization methods.

[0007] One aspect of this application provides a BIM-based method for installing pipes in large spaces, comprising: acquiring BIM model data of a large-space building, wherein the BIM model data includes: spatial coordinates and dimensional parameters of structural components, and physical parameters of the pipes to be installed; wherein the structural components include: structural beams, columns, and walls; and the physical parameters include: pipe material, pipe diameter, wall thickness, and density of the medium inside the pipe; performing three-dimensional meshing processing on the BIM model data to generate a meshed spatial model, and removing the mesh cells occupied by the structural components in the meshed spatial model to construct the pipe installation space;

[0008] Based on the pipe's self-weight and the weight of the medium inside the pipe from the physical parameters, the load per unit length of the pipe is calculated; within the pipe installation space, dynamic programming is used to optimize the arrangement of supports and hangers; based on the pipe's load per unit length and the continuous beam model of structural mechanics, a state transition equation is constructed, and the transition cost function of the state transition equation includes the maximum deflection value between adjacent support points and the maximum allowable support spacing constraint;

[0009] Based on the state transition equation, the optimal decision sequence is obtained by recursively solving the equation. Starting from the end of the pipeline and tracing back to the beginning, at each decision stage, the support point position that minimizes the cumulative deflection of all subsequent pipe segments is selected, generating the globally optimal support and hanger arrangement sequence. Based on the globally optimal support and hanger arrangement sequence and the unit length load of the pipeline, the deflection value of each pipe segment is calculated. The corresponding pre-supply height compensation curve is generated in the BIM model, and the pipeline installation scheme including the support and hanger positions and the pre-supply height is output.

[0010] Furthermore, the pipeline installation space is constructed, including: determining the three-dimensional boundary range of the space to be processed based on the building boundary information in the BIM model data, setting the grid unit size parameters, and dividing the space to be processed into a three-dimensional grid matrix; traversing each grid unit in the three-dimensional grid matrix and calculating the coordinates of the center point of each grid unit; converting the spatial coordinates and size parameters of the structural components into bounding box data, and determining whether the center point of each grid unit is located within the bounding box of any structural component; marking the status of the grid units according to the determination results to generate the available space geometry; and constructing a three-dimensional connected domain based on the set of available spaces to generate the data structure of the pipeline installation space.

[0011] In particular, traditional pipe support and hanger design uses a fixed-spacing arrangement, essentially simplifying the complex constraints in three-dimensional space into a one-dimensional equidistant distribution problem. While this simplification facilitates engineering implementation, it ignores the irregular distribution characteristics of structural components in large-space buildings. When encountering obstacles such as beams and columns, the actual support points are forced to deviate from their ideal positions, leading to increased spans and excessive deflection in local pipe sections. Furthermore, the cascading effects of this local adjustment propagate throughout the entire piping system, causing severe unevenness in deflection distribution.

[0012] This application discretizes the continuous three-dimensional installation space into a regular grid matrix, fundamentally changing the technical approach for support point selection.

[0013] Furthermore, the state transition equations are constructed, including: calculating the load per unit length of the pipeline based on physical parameters, whereby the load per unit length of the pipeline includes the load component generated by the pipeline's self-weight and the load component generated by the weight of the medium; extracting a set of candidate support point locations from the pipeline installation space; defining the state variables and state transition rules for dynamic programming; establishing the deflection distribution function between support points based on the pipeline's load per unit length and the structural mechanics model; constructing the state transition equations that include deflection constraints and spacing constraints; and initializing the boundary conditions for the dynamic programming solution process.

[0014] In particular, 3D meshing provides a complete solution space for dynamic programming algorithms. In traditional methods, designers can only adjust support points based on local information, lacking a global perspective. However, in the discretized mesh space, the system can evaluate all possible paths from the pipeline's starting point to its ending point, and find the optimal combination of support points that maximizes overall performance while satisfying deflection constraints through state transition equations.

[0015] For example, when a pipe needs to bypass a structural column, traditional methods might simply move the support point forward or backward, causing an imbalance between adjacent spans. However, dynamic programming methods based on gridded space comprehensively evaluate multiple available grid positions before and after the column and select the scheme that makes the deflection distribution most uniform across multiple spans.

[0016] Furthermore, a deflection distribution function between support points is established, including: defining the pipe segment between two adjacent support points as a calculation unit, setting the distance L between support points as an independent variable; and establishing the deflection curve equation under gravity load based on the total unit length load q of the pipe. Where E is the elastic modulus, I is the moment of inertia of the cross section, w is the deflection function, and x is the position coordinate along the pipe axis; the elastic modulus E and thermal expansion coefficient α corresponding to the pipe material are extracted from the physical parameters, and the moment of inertia of the pipe cross section is calculated based on the pipe diameter DN and wall thickness t. Calculate the axial thermal stress σ of the pipeline based on the design temperature variation range of the pipeline installation space. T=E×α×ΔT, where ΔT=T max -T min , among which, T max For the highest design temperature, T min This is the lowest design temperature;

[0017] Set simply supported boundary conditions w(0) = 0 and w(L) = 0, and calculate the gravitational deflection components.

[0018]

[0019] Calculate the temperature-induced deformation deflection component based on the axial expansion and contraction effect caused by temperature changes.

[0020]

[0021] Based on the gravitational deflection component w g (x) and temperature deformation deflection component w T (x), calculate the deflection distribution function w(x) = w g (x)+w T (x); For a pipe with simply supported ends, temperature changes mainly generate axial force, rather than direct deflection.

[0022] According to the deflection distribution function w(x) = w g (x)+w T (x), calculate the combined maximum deflection w under the combined effects of gravity and temperature deformation. max Calculate the maximum deflection under gravity at x = L / 2. and the maximum deflection due to temperature deformation The combined maximum deflection w is obtained max =w g,max +w T,max ;

[0023] Construct a multidimensional lookup table with support spacing L, pipe specification parameters (DN,t), material type, and temperature change ΔT as index keys to store the corresponding deflection distribution function coefficients and maximum deflection values, and generate a deflection calculation lookup table for use by the state transition equation.

[0024] In particular, in the design of piping systems for large-space buildings, traditional methods only consider the deflection caused by gravity loads. The significant characteristics of large-space buildings are large fluctuations in ambient temperature and long pipe spans. The deformation caused by temperature effects is often on the same order of magnitude as gravity deflection, and may even become the dominant factor under certain working conditions.

[0025] This application introduces the temperature deformation deflection component. Temperature changes not only cause axial expansion and contraction, but also transform into lateral deformation under constrained conditions, and this kind of deformation has a completely different distribution pattern from the gravity deflection. Therefore, based on the buckling theory of compression bars caused by axial thermal stress, this application uses the sine function to describe the spatial distribution of temperature deformation.

[0026] Furthermore, a state transition equation including deflection constraints and spacing constraints is constructed, including: defining the state variable S[i], which represents the optimal cumulative cost from the pipeline start point to the corresponding support point when the i-th point in the candidate support point position set is used as the current support point, where i is the index of the candidate support point in the position set; initializing the state of the candidate support point at the pipeline start point S[0]=0, and initializing the states of all other candidate support points to infinity; for each candidate support point i, traverse all the predecessor candidate support points k that satisfy the distance constraint, where k < i and the distance from candidate point k to i does not exceed 1.5 times the maximum allowable support spacing L max ; according to the spatial coordinates of the k-th and i-th support points in the candidate support point position set, calculate the support spacing L = |x i - x k |; according to the support spacing L, retrieve the corresponding comprehensive maximum deflection w max from the deflection calculation lookup table; when L > L max , calculate the spacing overrun penalty term P = M×(L - L max ), where M is the penalty coefficient; when L ≤ L 2 , the penalty term P = 0; calculate the transition cost C(k,i) = w max + λ×P, where λ is the penalty weight coefficient; update the state value S[i] = min{S[i], S[k] + C(k,i)}, and when S[k] + C(k,i) < S[i], record the optimal predecessor path[i] = k at the same time; max Process all candidate support points in sequence until the pipeline end, and finally select the point with the minimum S value among the candidate support points in the pipeline end area as the optimal end support point; starting from the optimal end support point, trace back to the pipeline start point through the path array to obtain the complete optimal support point sequence.

[0027]

[0028] ​Specifically, in the optimization problem of pipe supports and hangers, traditional dynamic programming methods use two-dimensional state variables f[i,j], where i represents the pipe position and j represents the number of support points already used. This setup requires pre-defining the search range for the optimal number of support points to find the optimal number. This is akin to knowing the approximate range of the answer before solving an equation. Furthermore, this two-dimensional state space leads to a quadratic increase in algorithm complexity. For a 100-meter-long pipe, considering a range of 10 to 20 support points, the number of states that need to be maintained and calculated exceeds 10,000. Each state also requires traversing all possible predecessor states, resulting in an exponential explosion in computational complexity. In engineering practice, designers are often forced to narrow the search range or use empirical values, thus missing the true optimal solution.

[0029] This application defines a one-dimensional state variable S[i], where S[i] represents the optimal cumulative cost from the starting point to the i-th candidate point as the support point, transforming the number of support points from an explicit constraint into an implicit outcome. The algorithm no longer focuses on the number of support points used, but rather on minimizing the cumulative cost. The number of support points is no longer an input parameter, but a natural reflection of the optimization result. When evaluating the decision to set a support point at each candidate location, the algorithm weighs the cost (construction complexity) of increasing support points against the benefits (deflection improvement). Support points are only set when the benefits outweigh the costs. For example, when a pipeline traverses a large span, the algorithm may automatically increase the support point density to control deflection; while in sections with better stiffness, it may automatically reduce the number of support points to lower construction costs. This adaptive characteristic is impossible to achieve with a two-dimensional state space, as the latter requires pre-specifying the number of support points for each section.

[0030] Furthermore, generating the globally optimal support and hanger layout sequence includes: determining the optimal end support point from the candidate support point location set; generating a support point index sequence based on the optimal end support point through path backtracking; extracting spatial location information from the support point index sequence and calculating the spatial relationship parameters of adjacent support points; obtaining the deformation characteristic values ​​of each pipe segment based on the spatial relationship parameters and pipe parameters; determining the support type based on the spatial location relationship of the support points; constructing a support and hanger layout data structure that includes spatial location, support type, deformation characteristics, and correlation relationships, and outputting the globally optimal support and hanger layout sequence.

[0031] Another aspect of this application provides a BIM-based large-space pipe installation system, comprising: a data acquisition module for acquiring BIM model data of a large-space building, the BIM model data including spatial coordinates and dimensional parameters of structural components, and physical parameters of the pipes to be installed; a spatial modeling module for performing three-dimensional meshing processing on the BIM model data to generate a meshed spatial model, and removing mesh cells occupied by structural components from the meshed spatial model to construct the pipe installation space; and a dynamic planning module for calculating the pipe unit length load based on the pipe self-weight and the weight of the medium inside the pipe in the physical parameters, and optimizing the arrangement of supports and hangers within the pipe installation space using dynamic planning methods, based on the pipe unit length load. A state transition equation is constructed using a continuous beam model in structural mechanics. The transition cost function of the state transition equation includes the maximum deflection value between adjacent support points and the maximum allowable support spacing constraint. The global optimization module obtains the optimal decision sequence by recursively solving the state transition equation. Starting from the end of the pipeline and tracing back to the starting point, the support point position that minimizes the cumulative deflection of all subsequent pipe segments is selected at each decision stage, generating a globally optimal support and hanger arrangement sequence. The installation scheme module calculates the deflection value of each pipe segment based on the globally optimal support and hanger arrangement sequence and the unit length load of the pipeline, generates the corresponding pre-supply height compensation curve in the BIM model, and outputs a pipeline installation scheme that includes the support and hanger positions and the pre-supply height.

[0032] Compared to existing technologies, the advantages of this application are:

[0033] Traditional methods, which employ fixed spacing or local adjustments for support and hanger placement, are prone to getting trapped in local optima, leading to an imbalance where some pipe segments exhibit excessive deflection while others are overly densely supported. This application addresses this by constructing a state transition equation, decomposing the complex global optimization problem into a series of interconnected subproblems. Utilizing the optimal substructure characteristics, it ensures that each decision stage selects the support point location that minimizes the cumulative deflection of all subsequent pipe segments. This reverse recursive solution process, moving from the pipe end to the starting point, fully considers the impact of each support point decision on the overall deflection distribution, avoiding the problem of early-stage decisions limiting the later optimization space in traditional methods.

[0034] Meanwhile, this application introduces a transfer cost function that includes deflection constraints and spacing constraints, simultaneously considering structural safety and economy during the optimization process. When the support spacing exceeds the allowable value, the introduction of a penalty term ensures the feasibility of the solution; while the cost assessment based on accurate deflection calculation guarantees the rationality of the support point distribution. This effectively solves the deflection control problem in the installation of long-distance pipelines in large spaces. Attached Figure Description

[0035] This application will be further described by way of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting; in these embodiments, the same reference numerals denote the same structures, wherein:

[0036] Figure 1 This is an exemplary flowchart of a BIM-based large-space pipe installation method according to some embodiments of this application;

[0037] Figure 2 This is an exemplary flowchart illustrating the construction of a multidimensional query table according to some embodiments of this application;

[0038] Figure 3 This is an exemplary flowchart illustrating the construction of state transition equations according to some embodiments of this application;

[0039] Figure 4 This is an exemplary flowchart illustrating the calculation cost function according to some embodiments of this application;

[0040] Figure 5 This is a schematic diagram of constraint processing logic according to some embodiments of this application;

[0041] Figure 6 This is a schematic diagram of the generation of support and hanger arrangement sequence according to some embodiments of this application. Detailed Implementation

[0042] The methods and systems provided in the embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0043] like Figure 1As shown, BIM model data for a large-space building is obtained. The BIM model data includes: spatial coordinates and dimensional parameters of structural components, and physical parameters of the pipes to be installed. Structural components include: structural beams, columns, and walls; physical parameters include: pipe material, pipe diameter, wall thickness, and density of the medium inside the pipe. The BIM model data is then processed into a 3D mesh to generate a meshed spatial model. Mesh cells occupied by structural components are removed from the meshed spatial model to construct the pipe installation space. Based on the pipe's self-weight and the weight of the medium inside the pipe from the physical parameters, the load per unit length of the pipe is calculated. Within the pipe installation space, dynamic programming is used to optimize the arrangement of supports and hangers. Based on the pipe... Using a continuous beam model with unit length load and structural mechanics, a state transition equation is constructed. The transition cost function of the state transition equation includes the maximum deflection value between adjacent support points and the maximum allowable support spacing constraint. Based on the state transition equation, the optimal decision sequence is obtained through reverse recursion, starting from the end of the pipeline and tracing back to the starting point. At each decision stage, the support point position that minimizes the cumulative deflection of all subsequent pipe segments is selected, generating a globally optimal support and hanger arrangement sequence. Based on the globally optimal support and hanger arrangement sequence and the unit length load of the pipeline, the deflection value of each pipe segment is calculated. The corresponding pre-supply height compensation curve is generated in the BIM model, and the pipeline installation scheme including the support and hanger positions and the pre-supply height is output.

[0044] The system acquires BIM model data for large-space buildings. This data includes: For structural component data, the system extracts the geometric definition of each component, including: Structural beams: starting coordinates (x1, y1, z1), ending coordinates (x2, y2, z2), cross-sectional width b, and cross-sectional height h; Columns: bottom center coordinates (x1, y1, z1), (x2, y2, z2 ... c ,y c ,z c ), height H, cross-sectional dimensions (a×b) or radius r; wall: reference line coordinate sequence [(x1,y1),(x2,y2),......,(x n ,y n )], bottom elevation z0, top elevation z1, thickness t.

[0045] Pipeline physical parameters are obtained by parsing the MEP (Mechanical, Electrical, and Plumbing) system data in the BIM model: Pipeline path: Centerline coordinate sequence P = {p1, p2, ..., p n}, where p i =(x i ,y i ,z i Material properties: The material code is mapped to the material database to obtain the elastic modulus E (e.g., for steel pipes, E = 2.06 × 10⁻⁶). 5 MPa), density ρ (e.g., steel ρ = 7850 kg / m³) 3Geometric parameters: nominal diameter DN (e.g., DN300), wall thickness t (e.g., 10mm), medium density ρ f (such as water ρ) f =1000kg / m 3 ).

[0046] The BIM model data is processed into a three-dimensional mesh to generate a meshed spatial model. The mesh cells occupied by structural components are removed from the meshed spatial model to construct the pipe installation space.

[0047] The meshing process employs a regular voxelization algorithm to discretize the continuous space into a uniform mesh:

[0048] Determine the spatial boundary: Xmin = min(x-coordinates of all components and pipes) - safety margin; Xmax = max(x-coordinates of all components and pipes) + safety margin; Ymin, Ymax, Zmin, Zmax are calculated similarly. Calculate the spatial dimensions: L x =X max -X min L y =Y max -Y min L z =Z max -Z min .

[0049] Convert each structural member into an axis-aligned bounding box (AABB): Beam bounding box: Considering the beam's inclination, calculate the minimum bounding box; Column bounding box: The bounding box of the wall is calculated based on the wall's outline and thickness. For each grid cell G[i,j,k], a point-bounding box intersection test is performed. Using a 3D flood filling algorithm, starting from any available grid cell, a connected set of available spaces is constructed through 26-neighborhood connectivity analysis. This transforms the complex 3D spatial problem into a discrete grid search problem, providing an efficient data foundation for subsequent dynamic programming optimization. Through gridded representation, collision detection, path search, and spatial querying can be performed quickly.

[0050] Extract the density value corresponding to the pipe material from the material database. For example, the density of carbon steel pipe is 7850 kg / m³. 3 Calculate the cross-sectional area of ​​the pipe based on its geometric parameters. Wherein, the outer diameter D is determined by the nominal diameter DN, and the inner diameter d = D - 2t. The unit length load generated by the self-weight of the pipe is q. p =ρ×A×g, where g is the acceleration due to gravity, 9.81 m / s². 2 .

[0051] For a medium flowing through a full pipe, its cross-sectional area is... The load per unit length generated by the weight of the medium is q f =ρ f ×A f ×g. The system automatically matches the density value based on the medium type, such as 1000 kg / m³ for water. 3 For steam, the pressure and temperature need to be determined by referring to a table.

[0052] The total unit length load of the pipeline is q = q p +q f This value will serve as the basic input parameter for all subsequent mechanical calculations.

[0053] In the three-dimensional meshed pipeline installation space, the system performs spatial sampling along the pipeline centerline trajectory. A parametric curve interpolation method is used to represent the pipeline path as P(s), where s is the arc length parameter. The pipeline path is discretized with a fixed step size Δs (e.g., 0.5m), and at each sampling point, the system checks the availability status of the corresponding mesh cell.

[0054] For each sampling point, the system not only checks the grid cell containing that point but also verifies whether there is sufficient installation space within a certain radius around it. This ensures the actual installability of the supports. In this way, a set of candidate support point locations C = {c1, c2, ..., c...} is generated. n Each candidate point contains three-dimensional coordinates and cumulative distance information along the pipeline.

[0055] Define the state variables for dynamic programming, where the state includes the index position of the current support point in the set of candidate support point positions, and the cumulative deflection value from the pipe start point to the current support point; to prevent excessively long single spans from causing uncontrolled deflection.

[0056] Based on the total unit length load q of the pipeline, the deflection distribution function of adjacent support points is calculated using a continuous beam model of structural mechanics, including: defining the pipeline segment between two adjacent support points as a calculation unit and setting the support point spacing L as an independent variable;

[0057] Based on the total unit length load q of the pipeline, the deflection curve equation under gravity load is established. Where E is the elastic modulus, I is the moment of inertia of the cross section, w is the deflection function, and x is the position coordinate along the pipe axis;

[0058] The elastic modulus E and coefficient of thermal expansion α corresponding to the pipe material are extracted from the physical parameters. Based on the pipe diameter DN and wall thickness t, the moment of inertia of the pipe section is calculated.

[0059] Calculate the axial thermal stress σ of the pipeline based on the design temperature variation range of the pipeline installation space. T =E×α×ΔT, where ΔT=Tmax -T min , among which, T max For the highest design temperature, T min This is the lowest design temperature;

[0060] Set simply supported boundary conditions w(0) = 0 and w(L) = 0, and calculate the gravitational deflection components; calculate the gravitational deflection components: Where: w g (x) represents the vertical downward deflection of the pipeline at position x caused by gravity load, in mm; x is the axial position coordinate measured from the left support point, with a value range of 0≤x≤L, in mm; q is the calculated total load per unit length of the pipeline, including the pipeline's own weight and the weight of the medium, in N / mm.

[0061] E is the elastic modulus of the pipe material, determined by the material type: Carbon steel pipe: E = 2.06 × 10⁻⁶ 5 MPa; Stainless steel pipe: E=1.93×10 5 MPa; Copper pipe: E=1.1×10 5 MPa; I is the moment of inertia of the pipe cross-section. The unit is mm. 4 Where D is the outer diameter of the pipe, d is the inner diameter of the pipe, d = D - 2t, t is the wall thickness; L is the axial distance between two adjacent support points, in mm;

[0062] The temperature deformation deflection component is calculated based on the axial expansion and contraction effect caused by temperature changes. For pipes simply supported at both ends, temperature changes mainly generate axial force, rather than direct deflection. Where: w T (x) represents the lateral deflection of the pipe at position x caused by temperature change, in mm; x is the axial position coordinate measured from the left support point, with a value range of 0 ≤ x ≤ L, in mm;

[0063] N T The axial force generated by temperature change, N T = A × E × α × ΔT, in N, where: A is the cross-sectional area of ​​the pipe. The unit is mm. 2 α is the coefficient of linear expansion of the pipe material, with units of 1 / ℃: Carbon steel pipe: α=11.7×10 -6 / ℃; Stainless steel pipe: α=16.0×10 -6 / ℃; Copper tube: α=16.5×10 -6 / ℃; ΔT is the design temperature change, ΔT=T max -T min, with the unit of °C; e0 is the amplitude of the initial geometric defect of the pipeline, taking e0 = L / 1000, representing one-thousandth of the initial bending, with the unit of mm; E is the elastic modulus of the pipeline material, with the unit of MPa; I is the moment of inertia of the pipeline cross-section, with the unit of mm 4 ; L is the axial distance between two adjacent support points, with the unit of mm; the thermal stress of a long-distance pipeline may exceed the self-weight stress; the superposition of temperature deformation and gravity deformation affects the actual deflection.

[0064] According to the gravity deflection component w g (x) and the temperature deformation deflection component w T (x), calculate the deflection distribution function w(x) = w g (x) + w T (x);

[0065] Calculate the maximum deflection under the action of gravity at x = L / 2 and the maximum deflection of temperature deformation

[0066] Obtain the comprehensive maximum deflection w max = w g,max + w T,max ;

[0067] As Figure 2 shown, construct a multi-dimensional query table, with the support spacing L, pipeline specification parameters (DN, t), material type, and temperature change ΔT as index keys, store the corresponding deflection distribution function coefficients and maximum deflection values, and generate a deflection calculation lookup table for the state transition equation to call, as shown in Table 1.

[0068] Table 1 Deflection Query Table for Carbon Steel Pipe CS, Temperature Change 30°C, Medium: Water, Heating Hot Water System

[0069]

[0070]

[0071] As Figure 3 shown, construct a state transition equation, including: define the state variable S[i] to represent the optimal cumulative cost from the start point of the pipeline to the i-th point when the i-th point in the candidate support point position set is used as the current support point, where i is the index of the candidate support point in the position set, with the value range of 0 ≤ i ≤ N - 1, and N is the total number of candidate support points; initialize the candidate support point state of the pipeline start point S[0] = 0, and initialize the states of all other candidate support points to infinity;

[0072] For each candidate support point i, traverse all the predecessor candidate support points k that satisfy the distance constraint, where k < i and the distance from candidate point k to i does not exceed 1.5×L max, L max is the maximum allowable support spacing, which is determined according to the pipe specification: when DN ≤ 100 mm, L max = 6 m; when 100 mm < DN ≤ 300 mm, L max = 8 m; when DN > 300 mm, L max = 10 m;

[0073] According to the spatial coordinates of the k-th and i-th support points in the set of candidate support point positions, calculate the support point spacing L = |x i - x k |, where x i and x k are the axial coordinates of the i-th and k-th candidate support points respectively; according to the support spacing L, retrieve the corresponding comprehensive maximum deflection w max from the deflection calculation lookup table; when L > L max , calculate the spacing overrun penalty term P = M × (L - L max ), where the penalty coefficient 2 ensures that the penalty term reaches the deflection magnitude level when overrun by 10%; when L ≤ L max , the penalty term P = 0;

[0074] Figure 4 As shown, calculate the transfer cost C(k, i) from support point k to support point i = w max + λ × P, where the penalty weight coefficient λ = 1000 to ensure that the spacing constraint is preferentially satisfied; update the state value S[i] = min{S[i], S[k] + C(k, i)}, and when S[k] + C(k, i) < S[i], record the optimal predecessor path[i] = k at the same time;

[0075] Process all candidate support points in sequence until the end of the pipe, and select the point with the minimum S value among the candidate support points within 0.5 m before and after the end as the optimal end support point; starting from the optimal end support point, trace back reversely through the path array to the start point of the pipe to obtain the complete optimal support point sequence, and the number of support points in this sequence is automatically determined by the algorithm.

[0076] By simplifying the state definition from two-dimensional f[i][j] to one-dimensional S[i], the dependence on the number of support points j is eliminated, making the number of support points a natural result of the optimization solution, and truly realizing the global optimization of the support hanger layout. In the actual installation of large-space pipes, the optimal number of support points should be the result of the optimization solution rather than a preset parameter. Presetting the number of support hangers: It requires multiple attempts with different numbers of support points, resulting in low computational efficiency; it may miss the true global optimal solution.

[0077] Figure 5 As As shown, according to the state transition equation, the optimal decision sequence is obtained by backward recursion. Starting from the end of the pipeline and tracing back to the starting point, at each decision stage, the position of the support point that minimizes the cumulative deflection of all subsequent pipe segments is selected to generate a globally optimal support hanger arrangement sequence, including:

[0078] Identify the candidate points in the end area of the pipeline from the set of candidate support point positions. Determine the end search range according to the pipe diameter DN: when DN ≤ 200mm, the search range is 1.0m; when 200mm < DN ≤ 500mm, the search range is 1.5m; when DN > 500mm, the search range is 2.0m. Select the candidate support points whose axial coordinates satisfy the condition xend - search range ≤ xi ≤ xend as the end candidate set, where xend is the coordinate of the end of the pipeline;

[0079] Select the candidate support point i with the minimum state value S[i] in the end candidate set opt As the optimal end support point, record its corresponding cumulative cost value S[i opt ;

[0080] Starting from the optimal end support point i opt Perform backward tracing through the path array, and sequentially obtain path[i opt , path[path[i opt until tracing back to the starting point of the pipeline path[i] = 0, forming a reverse support point index chain;

[0081] Reverse the reverse support point index chain to obtain an ordered support point index sequence [0, i1, i2,....., i opt from the starting point to the end of the pipeline. The length of the sequence is the total number of support points N opt ;

[0082] According to the support point index sequence, extract the corresponding three-dimensional space coordinates (x, y, z) from the set of candidate support point positions to generate a three-dimensional position coordinate sequence of the support hangers;

[0083] Calculate the three-dimensional space distance between adjacent support hangers

[0084] Record each spacing value and its ratio to the maximum allowable support spacing L max ;

[0085] For each pipe segment, according to its support spacing L i and the pipe specification parameters (DN, t), retrieve the corresponding comprehensive maximum deflection w max value and the deflection distribution function coefficient from the deflection calculation lookup table described in claim 4;

[0086] Based on the retrieved deflection distribution function coefficients, the locations of deflection extreme points within each pipe segment are calculated. And the actual deflection value at that location, including the gravitational deflection component and the temperature deformation deflection component;

[0087] The support type is determined based on the z-coordinate of each support point and the relative height difference between adjacent support points: when z i If the height is higher than the average height of adjacent support points, it is marked as a hanger; otherwise, it is marked as a support.

[0088] Construct a data structure for the layout of supports and hangers, including: the three-dimensional coordinate sequence of support points, support type identifier, adjacent spacing data, maximum deflection value and location of each pipe segment, cumulative cost value S[i_opt], ​​and the association index with structural components in the original BIM model;

[0089] Output the globally optimal support and hanger arrangement sequence for use in the subsequent pre-supply height calculation in S5.

[0090] like Figure 6 As shown, the deflection value of each pipe segment is calculated based on the globally optimal support and hanger arrangement sequence and the unit length load of the pipe.

[0091] Generate the corresponding pre-supply height compensation curve in the BIM model, and output the pipe installation scheme including the location of supports and hangers and the pre-supply height, including:

[0092] Extract the three-dimensional coordinate sequence of support points and adjacent spacing data L from the support and hanger layout data structure. i and the maximum deflection value of each pipe section;

[0093] For each pipe segment in the support and hanger arrangement sequence, according to its support spacing L i According to the deflection distribution function, the deflection values ​​at sampling points within the pipe section are calculated at 1m intervals:

[0094] Gravitational deflection components:

[0095] Temperature deformation deflection component:

[0096] Total deflection value: w(x)=w g (x)+w T (x);

[0097] Where q is the calculated total load per unit length of the pipeline;

[0098] Based on the comprehensive deflection value w(x) of each sampling point, calculate the corresponding pre-supply height compensation value h(x) = -w(x) to generate the pre-supply height compensation data sequence of the pipeline axis;

[0099] The pre-supplied height compensation data sequence and the three-dimensional position coordinate sequence of the supports and hangers are transformed into spatial coordinates to generate a compensated pipeline installation axis coordinate sequence, where the z-coordinate is adjusted to: z new (x)=z original (x)+h(x);

[0100] At each support / hanger location, calculate the actual installation height of the support / hanger based on the pre-supplied height compensation value and support type identifier for that point:

[0101] For hangers: Installation height = Structural beam bottom elevation - Pre-supplied height - Hanger rod length

[0102] For brackets: Installation height = Ground elevation + Pre-supplied height + Bracket height

[0103] The compensated pipeline installation axis coordinate sequence is converted into spline curve data that can be recognized by the BIM model, generating a geometric expression of the pre-supplied height compensation curve;

[0104] Create new pipe objects in the original BIM model, use the pre-supplied height compensation curve as the pipe centerline, and generate a three-dimensional pipe entity based on the pipe diameter and wall thickness parameters.

[0105] Create a support family instance at the support location, set the support type attributes, spatial location and installation height parameters, and establish the constraint relationship between the support and the pipe entity;

[0106] Generate a pipeline installation plan data file, including: support and hanger number, three-dimensional coordinates, type identification, installation height, adjacent spacing, maximum deflection value of each pipe section, pre-supply height compensation curve parameters, and spatial relationship with structural components;

[0107] Output updated BIM model and piping installation plan data files for construction and installation use.

[0108] The foregoing illustrative description of the present application and its embodiments is not restrictive and can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. The accompanying drawings are only one embodiment of the present application, and the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present application, such designs should fall within the scope of protection of this application. Furthermore, the word "comprising" does not exclude other elements or steps, and the word "a" preceding an element does not exclude the inclusion of "a plurality" of that element. Terms such as "first," "second," etc., are used to indicate names and do not indicate any specific order.

Claims

1. A BIM-based large space pipe installation method, characterized by, The method comprises the following steps: acquiring BIM model data of a large-space building, the BIM model data comprising spatial coordinates and size parameters of structural members and physical parameters of a pipeline to be installed, wherein the structural members comprise structural beams, columns and walls, and the physical parameters comprise pipeline material, pipeline diameter, wall thickness and medium density in the pipeline; performing three-dimensional meshing processing on the BIM model data to generate a meshed space model, and removing grid cells occupied by the structural members in the meshed space model to construct a pipeline installation space; calculating a pipeline unit length load according to the pipeline self-weight and the medium weight in the pipeline in the physical parameters; optimizing arrangement of supports and hangers in the pipeline installation space by using a dynamic programming method; constructing a state transition equation according to the pipeline unit length load and a structural mechanics continuous beam model, wherein a transition cost function of the state transition equation comprises a maximum deflection value between adjacent support points and a maximum allowable support spacing constraint; obtaining an optimal decision sequence by reverse recursion according to the state transition equation, starting from a pipeline end to trace back to a starting point, and selecting, at each decision stage, a support point position that minimizes the cumulative deflection of all subsequent pipeline segments to generate a globally optimal support and hanger arrangement sequence; calculating deflection values of the pipeline segments according to the globally optimal support and hanger arrangement sequence and the pipeline unit length load; generating a corresponding pre-provision height compensation curve in the BIM model, and outputting a pipeline installation scheme comprising support and hanger positions and pre-provision heights.

2. The BIM-based large-space pipeline installation method according to claim 1, wherein the construction of the pipeline installation space comprises: determining a three-dimensional boundary range of a space to be processed based on building boundary information in the BIM model data, setting a grid cell size parameter, and dividing the space to be processed into a three-dimensional grid matrix; traversing each grid cell in the three-dimensional grid matrix to calculate a center point coordinate of each grid cell; converting the spatial coordinates and size parameters of the structural members into bounding box data, and judging whether the center point of each grid cell is located within a bounding box of any structural member; performing state marking on the grid cells according to the judgment result to generate available space geometry; constructing a three-dimensional connected domain based on the available space set to generate a data structure of the pipeline installation space.

3. The BIM-based large-space pipeline installation method according to claim 1, wherein the construction of the state transition equation comprises: calculating the pipeline unit length load based on the physical parameters, wherein the pipeline unit length load comprises a load component generated by the pipeline self-weight and a load component generated by the medium weight; extracting a candidate support point position set from the pipeline installation space; defining state variables and state transition rules of the dynamic programming; establishing a deflection distribution function between the support points based on the pipeline unit length load and the structural mechanics model; constructing the state transition equation comprising the deflection constraint and the spacing constraint; initializing boundary conditions of the dynamic programming solving process.

4. The BIM-based large-space pipeline installation method according to claim 3, wherein the establishment of the deflection distribution function between the support points comprises: defining a pipeline segment between two adjacent support points as a calculation unit, and setting a support point spacing L as an independent variable. ​ ​ ​ Based on the total unit length load q of the pipeline, the deflection curve equation under the action of gravity load is established Wherein, E is the elastic modulus, I is the section moment of inertia, w is the deflection function, and x is the position coordinate along the pipeline axis. The elastic modulus E and the thermal expansion coefficient a corresponding to the pipe material are extracted from the physical parameters, and the pipe section inertia moment is calculated based on the pipe diameter DN and the wall thickness t According to the design temperature variation range of the pipeline installation space, the axial thermal stress σ of the pipeline is calculated T = E x α x ΔT, wherein ΔT = T max -T min , T max is the highest design temperature, and T min is the lowest design temperature; Set simply supported boundary conditions w(0) = 0 and w(L) = 0, calculate the gravity deflection component; According to the axial expansion effect caused by temperature change, calculate the temperature deformation deflection component; According to the gravity deflection component w g (x) and the temperature deflection component w T (x), the deflection distribution function w(x) = w g (x) + w T (x) is calculated; According to the deflection distribution function w(x) = w g (x) + w T (x), the comprehensive maximum deflection w max under the action of gravity and temperature deformation is calculated. Build a multi-dimensional query table to support the interval L, pipe specification parameters (DN, t), material type and temperature change ΔT as the index key, store the corresponding deflection distribution function coefficient and maximum deflection value, and generate the deflection calculation lookup table for the state transition equation call.

5. The BIM-based large space pipe installation method of claim 4, wherein: Compute gravity deflection components:

6. The BIM-based large space pipe installation method of claim 4, wherein: Computing the temperature deformation deflection component:

7. The BIM-based large space pipe installation method of claim 4, wherein: According to the deflection distribution function w(x) = w g (x) + w T (x), the comprehensive maximum deflection w max under the action of gravity and temperature deformation is calculated, comprising: The maximum deflection of the action of gravity is calculated at x = L / 2 and the maximum deflection of the temperature deformation The overall maximum deflection w is obtained max = w g,max + w T,max .

8. The BIM-based large space pipe installation method of claim 4, wherein: Build a state transition equation containing deflection constraints and interval constraints, including: Define the state variable S[i] to represent the optimal cumulative cost from the pipe starting point to the corresponding support point when the i-th point in the candidate support point position set is taken as the current support point, where i is the index of the candidate support point in the position set; Initialize the candidate support point state S[0] of the pipe starting point to 0, and initialize the states of all other candidate support points to infinity; For each candidate support point i, iterate over all predecessor candidate support points k that satisfy the distance constraint, where k < i and the distance from candidate point k to i is not more than 1.5 times the maximum allowed support spacing L max . According to the spatial coordinates of the kth and ith support points in the candidate support point position set, the support point spacing L = |x i -x k | is calculated. From the support spacing L, the corresponding overall maximum deflection w is retrieved from the deflection calculation lookup table max ; When L>L max When calculating the spacing exceeding the limit, the penalty term P = M × (LL) is used. max ) 2 Where M is the penalty coefficient; when L≤L max At that time, the penalty term P = 0; The transfer cost C(k,i) from support point k to support point i is calculated as w max + λ x P, where λ is a penalty weight coefficient. Update the state value S[i] = min{S[i], S[k] + C(k, i)} when S[k] + C(k, i) < S[i], and record the optimal predecessor path[i] = k at the same time; Process all candidate support points in turn until the pipe end, and finally select the point with the smallest S value in the candidate support points at the pipe end region as the optimal end support point; From the optimal end support point, backtrack to the pipe starting point through the path array to obtain the complete optimal support point sequence.

9. The BIM-based large space pipe installation method of claim 8, wherein: Generate a globally optimal support and hanger arrangement sequence, including: Determine the optimal end support point from the candidate support point position set; Based on the optimal end support point, generate a support point index sequence by path backtracking; According to the spatial relationship parameters of the support points, calculate the deformation characteristic values of each pipe segment; Determine the support type according to the spatial position relationship of the support points; Build a support and hanger arrangement data structure containing spatial position, support type, deformation characteristics and associated relationship, and output the globally optimal support and hanger arrangement sequence. Including:

10. A BIM-based large space piping installation system, characterized by, A data acquisition module acquires BIM model data of a large space building, and the BIM model data includes spatial coordinates and size parameters of structural members, and physical parameters of a pipe to be installed; A space modeling module performs three-dimensional gridding processing on the BIM model data to generate a gridded space model, and removes grid cells occupied by structural members in the gridded space model to build a pipe installation space; ​ The dynamic programming module calculates the pipe unit length load according to the pipe self-weight and the medium weight in the pipe among the physical parameters, adopts the dynamic programming method to optimize the layout of the support hanger in the pipe installation space, and constructs a state transition equation according to the pipe unit length load and a continuous beam model of structural mechanics, wherein the transition cost function of the state transition equation includes the maximum deflection value between adjacent support points and the maximum allowable support spacing constraint. The global optimization module obtains an optimal decision sequence by solving the state transition equation through reverse recursion, starts from the pipe end and backtracks to the starting point, selects the support point position that minimizes the cumulative deflection of all subsequent pipe sections at each decision stage, and generates a globally optimal support hanger layout sequence. The installation scheme module calculates the deflection value of each pipe section according to the globally optimal support hanger layout sequence and the pipe unit length load, generates the corresponding pre-supply height compensation curve in the BIM model, and outputs the pipe installation scheme containing the support hanger position and the pre-supply height.

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