Steel structure ground assembling and arching method

Abstract

The application provides a steel structure ground assembling and arching method, and belongs to the technical field of steel structure construction, which comprises the following steps: dividing assembling areas on the ground and setting temporary support structures according to design drawings; transporting steel structures to the assembling areas in sections and placing them according to design positions; assembling the steel structures in sections from arch feet, and connecting them by using high-strength bolts or welding; installing temporary transverse supports and inclined supports to enhance the stability of the structure; gradually lifting the arch rib sections by using hydraulic jacking equipment, and adjusting the temporary support structures at the same time; installing stress monitoring equipment at key nodes to monitor the stress state of the structure in real time; completing arch top closure, adjusting the arch curve, and ensuring that the design requirements are met; installing permanent transverse connecting pieces and tie rods to further enhance the overall rigidity; and removing the temporary support structures to complete the steel structure ground assembling and arching. The technical problem that it is difficult to accurately control the displacement and stress state of steel members during the arching process and ensure that the entire structure remains stable is solved.

Description

Technical Field

[0001] This invention belongs to the field of steel structure construction technology, and specifically relates to a method for assembling and arching steel structures on the ground. Background Technology

[0002] With the rapid development of infrastructure construction, an increasing number of large-span steel structure bridges and stadiums have emerged. These steel structure projects typically have large spans and heavy weights, often presenting numerous technical challenges during construction. Traditional steel structure construction methods usually require the erection of large temporary support frames on-site, followed by the hoisting and splicing of steel components section by section, and finally welding or high-strength bolt connections. This method is not only time-consuming and costly, but also highly dependent on on-site environmental conditions, susceptible to the effects of climate change, and even poses certain safety hazards.

[0003] Meanwhile, with the continuous development of technologies such as BIM and intelligent manufacturing, steel structure construction is also beginning to shift towards digitalization and intelligence. Some new construction methods, such as prefabricated steel component assembly and steel structure ground-based arching, are being widely applied. These new methods not only improve construction efficiency but also reduce on-site operational risks, bringing new opportunities to steel structure engineering construction.

[0004] However, precisely controlling the displacement and stress state of the steel components during the arching process to ensure the stability of the entire structure is also a major challenge. Summary of the Invention

[0005] In view of this, the present invention provides a method for arching steel structure on the ground, which can solve the technical problem that existing technologies have difficulty in accurately controlling the displacement and stress state of steel components during the arching process, and ensuring the stability of the entire structure.

[0006] This invention is implemented as follows:

[0007] This invention provides a method for assembling and arching a steel structure on the ground, comprising the following steps:

[0008] S10. According to the design drawings, divide the assembly area on the ground and set up temporary support structures;

[0009] S20. Transport the steel structure in sections to the assembly area and place them according to the design positions;

[0010] S30. Starting from the arch foot, steel structure is spliced ​​segment by segment, using high-strength bolts or welding for connection;

[0011] S40. Install temporary lateral supports and diagonal braces to enhance structural stability;

[0012] S50. Using hydraulic jacking equipment, gradually lift the arch rib segments while adjusting the temporary support structure.

[0013] S60. Install stress monitoring equipment at key nodes to monitor the stress on the structure in real time;

[0014] S70. Complete the arch closure and adjust the arch curve to ensure it meets the design requirements;

[0015] S80. Install permanent lateral connectors and tie rods to further enhance overall rigidity;

[0016] S90. Remove the temporary support structure and complete the ground assembly and arching of the steel structure.

[0017] Specifically, step S10 includes: dividing the ground into areas for steel structure assembly according to the design drawings, and setting up temporary support structures within these areas. When dividing the assembly area, the length, width, and height parameters of the area are measured and determined using digital measurement methods. When setting up the temporary support structures, engineering drawing software is used to design the layout scheme of the support components, including the position, cross-sectional dimensions, and connection methods of the support components, to ensure that necessary support force is provided during subsequent assembly.

[0018] Furthermore, step S20 specifically includes: transporting the prefabricated steel structure components in sections to the assembly area and placing them in designated positions according to design requirements. In this process, BIM modeling method is first used to create a three-dimensional model of each component and mark its number, size and position information; after being transported to the assembly area, the components are accurately placed in the design position.

[0019] Furthermore, step S30 specifically includes: starting from the arch foot, splicing and connecting the steel structure segment by segment using high-strength bolts or welding. When determining the connection method for each key node, it is necessary to comprehensively consider the structural stress, construction difficulty, or economic factors to provide the optimal connection scheme. In the actual splicing process, it is necessary to use existing robotic welding or automated bolt installation equipment, combined with existing machine vision methods, to identify and adjust the position and posture of the components to ensure connection quality. At the same time, it is also necessary to use real-time detection of the component stress state and dynamically adjust the welding parameters or bolt preload to avoid exceeding limits.

[0020] Furthermore, step S40 specifically includes: after completing the steel structure splicing, installing temporary lateral supports and diagonal braces to enhance the stability of the entire structure; firstly, predicting the maximum displacement and stress that may occur in the arch structure during the arching process; and then determining the optimal arrangement position, cross-sectional size and connection method of the temporary support components so that the entire structure can maintain sufficient stability during the arching process.

[0021] Furthermore, step S50 specifically includes: using hydraulic jacking equipment to gradually lift the arch rib segments to complete the arching process of the entire steel structure; firstly, based on the stress characteristics of the arch structure, the maximum allowable lifting amount and speed at each stage need to be calculated, and the optimal lifting path and speed need to be determined; during the actual lifting process, the displacement and stress state of the structure need to be monitored in real time, and the parameters of the hydraulic equipment need to be dynamically adjusted to ensure that the lifting process is stable and controlled; at the same time, the stress situation of the temporary supports during the lifting process also needs to be calculated in real time, and the arrangement and cross-sectional dimensions of the supports need to be adjusted.

[0022] Furthermore, step S60 specifically includes: installing stress monitoring equipment at key nodes to monitor the stress of the entire steel structure in real time; firstly, the stress distribution of key nodes needs to be predicted using finite element analysis to determine the key monitoring locations; then, the optimal installation location and number of monitoring devices are calculated; during actual installation, machine vision is used to accurately locate the monitoring points, and automated installation technology is used to complete the installation of the equipment.

[0023] Furthermore, step S70 specifically includes: after the arch closure is completed, the entire arch curve is adjusted to ensure that it meets the design requirements; firstly, a curve fitting method is used to reconstruct the mathematical model of the entire arch curve based on the completed arch rib segments; then, the arch curve is dynamically adjusted to make it as close as possible to the design requirements; after the arch closure is completed, the welds of key nodes also need to be inspected and verified to ensure that the welding quality meets the standards.

[0024] Furthermore, step S80 specifically includes: installing permanent lateral connectors and tie rods to further enhance the overall rigidity of the entire steel structure; firstly, it is necessary to determine the optimal arrangement position and cross-sectional dimensions of the connecting components so that they can withstand the horizontal forces and torques that may occur during use; in actual installation, it is also necessary to use machine vision methods to accurately position the connectors and adopt automated welding or high-strength bolt fastening technology to ensure reliable connection.

[0025] Furthermore, step S90 specifically includes: after completing the installation of all permanent connecting components, dismantling the temporary support structure to fully complete the ground assembly and arching process of the entire steel structure; during the dismantling process, it is necessary to first predict and analyze the temporary stress and displacement that may occur during the dismantling process, and give the best dismantling sequence and method; then, use automated dismantling technology to quickly and efficiently complete the dismantling of the support structure; during this process, it is also necessary to continue to monitor the stress of the main structure in real time, and if it is found to exceed the allowable range, the dismantling should be stopped immediately and adjustments should be made.

[0026] Furthermore, the arch axis of the arch is a parabola, and its expression is: Where x is the coordinate along the span direction, y is the height coordinate of the arch, L is the span of the arch, and f is the rise of the arch. This equation allows us to determine the coordinates of key nodes, such as the arch feet (0,0) and (L,0), and the arch crown. and quarter point and

[0027] Furthermore, for each critical node, its axial force N, bending moment M, and shear force Q need to be calculated to assess the stress state at the node. The axial force can be expressed as... Where q is the uniformly distributed load, and θ is the angle between the tangent to the arch axis at that point and the horizontal line; the bending moment can be expressed as... Shear force can be expressed as These stress calculation formulas can be used to determine the stress range σ for each critical node. min and σ max .

[0028] Furthermore, to gradually adjust the arched curve to closely approximate the target curve, an iterative optimization method can be employed. Assuming the adjustment process is divided into n steps, the curve equation after each step can be expressed as: Where i is the adjustment step number, f i Let Δy be the adjusted sag in step i. i (x) is the adjustment function for the i-th step. The adjustment function can be expressed as a Fourier series expansion: Where m is the number of series terms, a k，i and b k，i To adjust the parameters. The goal is to make the final curve y n As close as possible to the design curve y design This can be achieved by minimizing the mean square error. To achieve this.

[0029] Furthermore, to consider the overall vibration and stress conditions, a more complex model is needed. The vibration equation can be expressed as follows: Where m is the equivalent mass, c is the damping coefficient, k is the stiffness coefficient, and F(t) is the time-varying external force function. The internal force equilibrium equation can be expressed as: Where N is the axial force, Q is the shear force, M is the bending moment, and q x and q y y' represents the distributed loads in the x and y directions, respectively, and y' is the slope of the arch axis.

[0030] Furthermore, the equivalent mass m can be obtained through integration. Where ρ is the density of steel, and A(x) is the cross-sectional area. The stiffness coefficient k can be simplified to... Where E is the elastic modulus and I is the moment of inertia of the cross section. The natural frequency ω n Then it can be calculated as The damping coefficient c can be calculated from the estimated damping ratio ζ as c = 2ζω n m.

[0031] Furthermore, the temperature change ΔT will result in an additional thermal strain ε thermal =αΔT, where α is the coefficient of linear expansion. Furthermore, foundation settlement also affects the stress state of the arch, which can be considered by modifying the boundary conditions y(0) = δ1 and y(L) = δ2, where δ1 and δ2 are the settlement amounts at both ends, respectively. For long-span bridges, the influence of wind load cannot be ignored; it can be addressed by... To calculate, where ρ air air density, v is wind speed, C d A is the drag coefficient. projected (x) represents the projected area per unit length.

[0032] Optionally, fatigue analysis should also be conducted to assess the fatigue life of critical connection nodes. Miner's linear cumulative damage theory can be used. Where D represents cumulative damage, n i The stress amplitude is σ i The number of loops, N i This represents the fatigue life under this stress amplitude. When D reaches 1, the structure is considered to have reached its fatigue life.

[0033] Optionally, the number of terms m in the Fourier series expansion used during the adjustment of the arched curve is generally 5-10, which can be adjusted according to the required fitting accuracy. The step size factor λ is adjusted accordingly. i The initial value can be set to 1, and then dynamically adjusted through an optimization algorithm to minimize the overall error.

[0034] Optionally, when using the Newmark-β numerical integration method to solve the vibration equation, the commonly used parameter values ​​are α = 0.25, β = 0.5, and γ = 0.5. The selection of the time step Δt needs to be balanced between the required computational accuracy and efficiency, and is usually taken as 1 / 10 to 1 / 20 of the natural period.

[0035] It should be noted that the parameters L represent the arch span in meters; f represents the arch rise in meters; x represents the coordinate along the span direction in meters; y represents the arch height in meters; q represents the uniformly distributed load in kilonewtons per meter; θ represents the angle between the tangent to the arch axis at a point and the horizontal line in radians; N represents the axial force in kilonewtons; M represents the bending moment in kilonewton-meters; Q represents the shear force in kilonewtons; A represents the cross-sectional area in square meters; W represents the section modulus in cubic meters; σ represents the stress in megapascals. The parameters E represent the elastic modulus of steel in gigapascals; I represents the moment of inertia of the cross section in cubic meters; ρ represents the steel density in kilograms per cubic meter; g represents the acceleration due to gravity in meters per square second. The parameters t represent time in seconds; ω represents the circular frequency in radians per second; ζ represents the damping ratio, dimensionless. The parameter ΔT represents the temperature change in degrees Celsius; α is the coefficient of linear expansion in degrees Celsius; δ1 and δ2 are the foundation settlements at both ends in meters. The parameter ρ... air air density is expressed in kilograms per cubic meter; v is wind speed, expressed in meters per second; C d A is the drag coefficient, dimensionless; projected (x) represents the projected area per unit length, in square meters. The parameter n... i The stress amplitude is σ i The number of iterations, dimensionless; N i For stress amplitude σ i The fatigue life is dimensionless; D is the cumulative damage, dimensionless. In the arched curve adjustment process, parameter n is the number of adjustment steps, dimensionless; m is the number of terms in the Fourier series expansion, dimensionless; a k,i and b k,i λ is the Fourier coefficient of the k-th term in the i-th adjustment, which is dimensionless; i Let be the adjustment step size factor for the i-th step, which is dimensionless.

[0036] Compared with existing technologies, the beneficial effects of the steel structure ground assembly arching method provided by this invention are: the method fully integrates advanced technologies such as digital measurement, structural analysis, and automated construction, which greatly improves the accuracy, efficiency and safety of construction.

[0037] Firstly, regarding the design and dismantling of temporary supports, this method employs structural analysis algorithms to accurately predict the maximum displacement and stress that may occur during the arching process, thereby optimizing the layout and dimensions of the support structure and significantly reducing the number and complexity of temporary supports. Simultaneously, automation technology is used in the dismantling phase, enabling rapid and efficient dismantling of the supports, which not only shortens the construction period but also improves operational safety.

[0038] Secondly, regarding arch control, this method employs an optimized control algorithm that dynamically adjusts the parameters of the hydraulic jacking equipment based on real-time monitoring of the structural stress, ensuring the stability of the entire structure during arching and preventing excessive displacement and stress. Simultaneously, a stress monitoring system is also included to monitor the stress state of key nodes in real time, providing a basis for subsequent adjustments.

[0039] Finally, regarding the adjustment of the arch curve, this method employs an iterative optimization strategy, using Fourier series fitting to gradually correct the arch until it finally meets the design requirements. This method not only converges quickly but also fully considers the actual stress conditions of the structure, ensuring that the adjusted arch meets the strength and performance indicators.

[0040] In summary, the steel structure ground assembly arching method proposed in this invention makes full use of digital and intelligent technologies, and solves the technical problem that existing technologies are unable to accurately control the displacement and stress state of steel components during the arching process, thus ensuring the stability of the entire structure. Attached Figure Description

[0041] Figure 1 A flowchart of the method provided by the present invention;

[0042] Figure 2 This is a schematic diagram of the key nodes in Example 1. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0044] like Figure 1 The diagram shown is a flowchart of a steel structure ground assembly and arching method provided by the present invention. This method includes the following steps:

[0045] S10. According to the design drawings, divide the assembly area on the ground and set up temporary support structures;

[0046] S20. Transport the steel structure in sections to the assembly area and place them according to the design positions;

[0047] S30. Starting from the arch foot, steel structure is spliced ​​segment by segment, using high-strength bolts or welding for connection;

[0048] S40. Install temporary lateral supports and diagonal braces to enhance structural stability;

[0049] S50. Using hydraulic jacking equipment, gradually lift the arch rib segments while adjusting the temporary support structure.

[0050] S60. Install stress monitoring equipment at key nodes to monitor the stress on the structure in real time;

[0051] S70. Complete the arch closure and adjust the arch curve to ensure it meets the design requirements;

[0052] S80. Install permanent lateral connectors and tie rods to further enhance overall rigidity;

[0053] S90. Remove the temporary support structure and complete the ground assembly and arching of the steel structure.

[0054] The specific implementation methods of the above steps are described in detail below:

[0055] The specific implementation method of step S10 is as follows:

[0056] According to the design drawings, the length, width, and height parameters of the assembly area must first be measured and determined using digital measurement methods. Specifically, a total station or laser rangefinder can be used to measure the three-dimensional coordinates of the assembly area. By analyzing and processing this data, the length L, width W, and height H of the area can be accurately obtained.

[0057] After determining the dimensions of the assembly area, the next step is to design the layout of the temporary support structure using engineering drawing software. Finite element analysis can be used here to predict the maximum displacement and stress that may occur in the entire steel structure during assembly. Based on these analysis results, the optimal placement and cross-sectional dimensions A of the temporary support components are determined. s The connection method ensures that the entire structure maintains sufficient stability during the arching process. The erection of temporary support structures should meet the following design requirements:

[0058] 1) Supporting force F s It should be greater than the maximum force F exerted by the steel structure during the arching process. m ax, i.e., F s >F m ax. Where F m ax can be predicted through finite element analysis.

[0059] 2) Displacement δ of the supporting structure s It should be less than the maximum allowable displacement δ of the steel structure. a , i.e. δ s <δ a Here δ a It is generally taken as 1 / 500 of the total span of the steel structure.

[0060] 3) Stress σ of the supporting structure s It should be less than the allowable stress σ of the material. a , that is, σ s <σa Where σ a It can be determined based on the material strength characteristics of the supporting components.

[0061] By weighing and optimizing the above factors, a reasonable temporary support structure layout scheme can be derived. In actual construction, this scheme will need to be adjusted appropriately based on site conditions.

[0062] The specific implementation method of step S20 is as follows:

[0063] First, BIM modeling is used to create a 3D model of each prefabricated steel structure component, and the model is labeled with its number, dimensions, and expected installation location. This facilitates the precise placement of each component in its designed position during subsequent transportation and placement.

[0064] After the components are transported to the assembly area, a positioning measurement method is needed to check and adjust the actual placement of each component. Specifically, equipment such as a total station or laser tracker can be used to measure the three-dimensional coordinates of the component after placement. These measurement data are then compared with the design location in the BIM model. If there are deviations, adjustments need to be made to ensure that each component is accurately placed in the designated position.

[0065] To improve positioning accuracy, machine vision technology can also be used. Several visual markers with known coordinates are set around the component's placement location. By identifying and measuring these markers, the component's three-dimensional pose information can be deduced, thus determining its placement location more accurately.

[0066] In summary, the purpose of step S20 is to ensure that each prefabricated component is placed precisely in the assembly area according to the designed position and orientation, laying the foundation for subsequent steel structure splicing.

[0067] The specific implementation method of step S30 is as follows:

[0068] Starting from the arch foot, the steel structure is spliced ​​and connected segment by segment. When determining the connection method for each key node, the following factors need to be considered comprehensively:

[0069] 1) Structural stress conditions. Based on finite element analysis, the stress level and stress state at each node are determined, and connection methods capable of withstanding these stresses are selected.

[0070] 2) Construction difficulty. Different connection methods have different implementation processes, and it is necessary to weigh factors such as operational complexity and accuracy requirements to select a simpler and more reliable method.

[0071] 3) Economy. Under the premise of meeting the load-bearing capacity and construction requirements, choose the connection method with lower cost as much as possible, such as high-strength bolt connection is better than welding.

[0072] Based on the above comprehensive considerations, the optimal connection scheme for each key node can be provided. In the actual assembly process, it is necessary to use robotic welding or automated bolt installation equipment, combined with machine vision technology, to monitor and adjust the position and orientation of the components in real time to ensure connection quality.

[0073] Simultaneously, strain sensors are needed to monitor the stress state of the components in real time and dynamically adjust welding parameters or bolt preload to prevent stress exceeding limits. An upper stress limit σ can be set here. lim Only when the real-time monitored stress σ satisfies σ < σ lim Only when this is done can the splicing work continue.

[0074] In summary, the purpose of step S30 is to use advanced automated construction technology to ensure that the key nodes of the steel structure can be reliably spliced ​​and connected, laying a solid foundation for the subsequent arching.

[0075] The specific implementation method of step S40 is as follows:

[0076] After the steel structure is assembled, temporary lateral supports and diagonal braces need to be installed to enhance the stability of the entire structure. First, the finite element method is still required to determine the maximum possible displacement δ of the arch structure during the arching process. max and maximum stress σ max Make predictions.

[0077] Based on these analysis results, the optimal arrangement location and cross-sectional dimension A of the temporary support components were determined. s The connection method ensures that the entire structure maintains sufficient stability during the arching process. An upper limit for displacement δ can be set here. lim and upper limit of stress σ lim Temporary support structures should meet the following design requirements:

[0078] 1) Displacement δ of the supporting structure s It should be less than the upper limit of displacement, i.e., δ s <δ lim . General δ lim It is taken as 1 / 500 of the total span of the steel structure.

[0079] 2) Stress σ of the supporting structure s It should be less than the upper limit of stress, i.e., σ s <σ lim Where σ lim It can be determined based on the material strength characteristics of the supporting components.

[0080] 3) Supporting force F s It should be greater than the maximum force F exerted by the steel structure during the arching process. max That is, F s >F max .

[0081] By weighing and optimizing the above factors, a reasonable temporary support structure layout scheme can be derived. During actual construction, this scheme needs to be adjusted appropriately based on site conditions to ensure sufficient stability of the entire arch structure during arch erection.

[0082] The specific implementation method of step S50 is as follows:

[0083] Using hydraulic jacking equipment, the arch rib segments are gradually lifted to complete the arching process of the entire steel structure. First, based on the stress characteristics of the arch structure, the maximum allowable jacking amount Δh and the maximum jacking speed v for each stage need to be calculated, and the optimal jacking path and speed need to be determined.

[0084] During the actual jacking process, it is necessary to monitor the displacement δ and stress σ of the structure in real time and dynamically adjust the parameters of the hydraulic equipment to ensure a smooth and controlled jacking process. The following thresholds can be set here:

[0085] 1) Displacement limit δ lim The displacement δ monitored in real time should satisfy δ < δ lim . General δ lim It is taken as 1 / 500 of the total span of the steel structure.

[0086] 2) Stress limit σ lim The stress σ monitored in real time should satisfy σ < σ lim Where σ lim It can be determined based on the material's strength characteristics.

[0087] At the same time, it is also necessary to calculate the stress on the temporary support during the jacking process in real time, and dynamically adjust the arrangement and cross-sectional dimensions of the support to ensure that it can continuously provide sufficient stability.

[0088] In summary, the purpose of step S50 is to ensure that the entire arch structure can be raised smoothly by precisely controlling the jacking process, thus laying the foundation for the subsequent arch closure.

[0089] The specific implementation method of step S60 is as follows:

[0090] Stress monitoring equipment is installed at key nodes to monitor the stress on the entire steel structure in real time. First, finite element analysis is used to predict the stress distribution at the key nodes and determine the locations requiring focused monitoring. An upper stress limit σ can be set here. limIf the real-time monitored stress σ exceeds this upper limit, the structure needs to be adjusted or other measures need to be taken in a timely manner.

[0091] After determining the monitoring locations, the optimal number and placement of sensors need to be calculated. This involves balancing factors such as sensor measurement accuracy and monitoring area coverage. Generally, as many sensors as possible should be deployed to improve monitoring reliability.

[0092] In actual installation, machine vision technology is needed to accurately locate monitoring points, and automated installation processes are employed to complete the equipment installation. This not only improves installation efficiency but also ensures the accuracy of sensor installation, providing reliable basic data for subsequent real-time monitoring.

[0093] In summary, the purpose of step S60 is to establish a reliable structural health monitoring system to monitor the stress state of the entire steel structure in real time during the arching process, providing a basis for subsequent structural adjustments and optimizations.

[0094] The specific implementation method of step S70 is as follows:

[0095] After the arch is closed, the entire arch curve needs to be adjusted to ensure it meets the design requirements. First, a curve fitting method is used to reconstruct the mathematical model of the entire arch curve based on the completed arch rib segments. Mathematical methods such as cubic spline interpolation can be used to fit the discrete arch rib nodes into a continuous curve.

[0096] Then, the fitted curve is dynamically adjusted to make it as close as possible to the ideal arch shape required by the design. Here, an arch deviation index Δ can be defined to represent the maximum deviation between the actual arch shape and the ideal arch shape. During the adjustment process, the position of the arch rib segments needs to be continuously optimized to make Δ as small as possible below a preset allowable deviation Δ. lim .

[0097] After the arch is closed, the welds at key nodes need to be inspected and verified to ensure that the welding quality meets the standards. Non-destructive testing techniques, such as ultrasonic testing or magnetic particle testing, can be used to check the internal quality of the welds. Only when the weld quality meets the design requirements can the arch curve be finally determined.

[0098] In summary, the purpose of step S70 is to ensure that the entire steel structure arch ultimately meets the design standards by dynamically adjusting the arch curve and strictly controlling the weld quality.

[0099] To achieve key point stress monitoring and arch curve adjustment in S60 and S70, a series of equations and functions need to be established. The detailed scheme is as follows:

[0100] 1. Key point determination and stress range calculation (S60)

[0101] First, key points need to be identified. Typically, key points include the arch foot, arch crown, and quarter points of the span. The following set of equations can be used to determine the location of key points and calculate the stress range:

[0102] a) Equation of the arch axis:

[0103] Assuming the arch axis is a parabola, its equation can be expressed as:

[0104] Where: x is the coordinate along the span direction; y is the height coordinate of the arch; L is the span of the arch; f is the rise of the arch;

[0105] b) Key point coordinates:

[0106] Arches: (0,0) and (L,0);

[0107] dome:

[0108] Quarter point: and

[0109] c) Stress calculation:

[0110] For each critical point, axial force, bending moment, and shear force need to be calculated. The following are simplified stress calculation equations:

[0111] Axial force:

[0112] Bending moment: (1 is) (1 is) for );

[0113] Shear force: (1 is) );

[0114] Where: q is the uniformly distributed load; θ is the angle between the tangent to the arch axis at that point and the horizontal line;

[0115] Stress range: for

[0116] Where: A is the cross-sectional area; W is the cross-sectional modulus.

[0117] 2. Adjustment of the arched curve (S70)

[0118] To gradually adjust the arched curve to closely approximate the target curve, an iterative method can be used. Assuming the adjustment process is divided into n steps, the curve equation after each step can be expressed as:

[0119]

[0120] Where: i is the adjustment step number (i = 1, 2, ..., n); f i Let Δy be the adjusted sag in step i; i (x) is the adjustment function for the i-th step;

[0121] The adjustment function can be expanded using Fourier series:

[0122]

[0123] Where: m is the number of terms in the Fourier series; a k,i ,b k,i The coefficient of the k-th term in the i-th step adjustment; the goal is to make the final curve y n As close as possible to the design curve y design This goal can be achieved by minimizing the mean squared error: (y n For y design ) 2 dx→min.

[0124] 3. Overall vibration and stress conditions considered

[0125] To consider the overall vibration and stress conditions, a more complex model is needed:

[0126] a) Vibration equation:

[0127] Assuming the arch bridge is a simplified single-degree-of-freedom system, its vibration equation can be expressed as:

[0128]

[0129] Where: m is the equivalent mass; c is the damping coefficient; k is the stiffness coefficient; F(t) is the time-varying external force function;

[0130] b) Force analysis: Consider the internal force equilibrium equations of the arch:

[0131]

[0132] Q+Ny′=0;

[0133] Where: N is the axial force; Q is the shear force; M is the bending moment; q x ,q y y' represents the components of the distributed load in the x and y directions; y' is the slope of the arch axis.

[0134] 4. Variable and Constant Descriptions: L is the span of the arch (unit: meters); f is the rise of the arch (unit: meters); x is the coordinate along the span direction (unit: meters); y is the height coordinate of the arch (unit: meters); q is the uniformly distributed load (unit: kN / m); θ is the angle between the tangent to the arch axis at a point and the horizontal line (unit: radians); N is the axial force (unit: kN); M is the bending moment (unit: kN·m); Q is the shear force (unit: kN); A is the cross-sectional area (unit: m²). 2 W is the section modulus (unit: m). 3 σ is the stress (unit: MPa); E is the elastic modulus of steel (unit: GPa); I is the moment of inertia of the cross section (unit: m). 4 ); ρ is the density of steel (unit: kg / m³) 3 g is the acceleration due to gravity (unit: m / s²). 2 ); t is time (unit: seconds); ω is the angular frequency (unit: rad / s); ζ is the damping ratio (dimensionless).

[0135] 5. Explanation of Uncommon Functions and Algorithms

[0136] a) Fourier series:

[0137] Fourier series are linear combinations of simple sine functions that represent periodic functions. In this scheme, Fourier series are used to describe the adjustment function of the arch curve.

[0138] b) Least squares method:

[0139] Least squares is a mathematical optimization technique that finds the best function fit for data by minimizing the sum of squared errors. In arch curve adjustment, this method is used to determine the optimal adjustment parameters.

[0140] c) Newmark-β method:

[0141] The Newmark-β method is a numerical integration method for solving dynamic equations. When considering the effects of vibration, this method can be used to discretize and solve the vibration equations.

[0142]

[0143] Where α, β, and γ are the parameters of the Newmark-β method; Δt is the time step.

[0144] 6. The following is a detailed calculation process.

[0145] Step 1: Initialize parameters

[0146] Define the geometric parameters of the arch: L, f;

[0147] Determine material properties: E, ρ, σyield (Yield strength);

[0148] Define the cross-sectional properties: A(x), I(x), W(x) (which may vary with x);

[0149] Define the load as q(x) (which may be non-uniformly distributed);

[0150] Determine the number of adjustment steps n and the number of Fourier series terms m;

[0151] Step 2: Calculate the initial arch shape

[0152] Calculate the initial shape using the initial arch axis equation:

[0153]

[0154] Step 3: Identify key points

[0155] Calculate the coordinates of the arch foot, arch crown, and quarter points.

[0156] Step 4: Calculate the initial stress distribution

[0157] For each key point:

[0158] a) Calculate axial force, bending moment, and shear force;

[0159] b) Calculation stress range: σ min and σ max ;

[0160] c) Check if the allowable stress is exceeded: σ max <σ allow ;

[0161] Step 5: Establish a vibration model

[0162] a) Calculate the equivalent mass m:

[0163]

[0164] b) Estimate the stiffness coefficient k:

[0165] (Simplified to an equivalent beam);

[0166] c) Calculate the natural frequency ω n :

[0167]

[0168] d) Estimate the damping ratio ζ (usually 0.02-0.05);

[0169] e) Calculate the damping coefficient c:

[0170] c=2ζωn m;

[0171] Step 6: Adjust the arched curve;

[0172] For each step of adjusting i = 1 to n:

[0173] a) Calculate the error between the current curve and the target curve:

[0174] e i (x)=y design (x)-y i-1 (x);

[0175] b) Fitting the error using Fourier series:

[0176]

[0177] c) Update the arch curve:

[0178]

[0179] Where λ i It is an adjustment step size factor (0 < λ) i ≤1);

[0180] d) Recalculate the stress distribution at key points;

[0181] e) Perform dynamic analysis:

[0182] Solve the vibration equations using the Newmark-β method;

[0183] Check if the maximum displacement and acceleration are within the allowable range;

[0184] f) If the stress or vibration exceeds the allowable range, reduce λ. i And repeat ce;

[0185] Step 7: Optimize and adjust the process;

[0186] Use optimization algorithms (such as gradient descent) to find the optimal λ. i Sequence, to minimize the overall error:

[0187]

[0188] Simultaneously satisfying stress and vibration constraints.

[0189] Step 8: Final Verification

[0190] A comprehensive static and dynamic analysis was conducted on the final arch to ensure that all design requirements were met.

[0191] 7. Supplementary Explanation

[0192] a) Considering the effect of temperature:

[0193] Temperature changes can cause arch deformation and additional stress. The stress calculation formula can be modified by adding a temperature strain term.

[0194] ε thermal =αΔT;

[0195] Where: α is the coefficient of linear expansion; ΔT is the temperature change;

[0196] b) Considering foundation settlement:

[0197] Foundation settlement affects the stress state of the arch. This effect can be considered by modifying the boundary conditions:

[0198] y(0)=δ1;

[0199] y(L)=δ2;

[0200] δ1 and δ2 are the settlement amounts at both ends.

[0201] c) Wind load effect:

[0202] For long-span arch bridges, wind loads can significantly affect structural behavior. Wind loads can be incorporated as additional distributed forces into the stress analysis.

[0203]

[0204] Where: ρ air air density; v is wind speed; C d A is the drag coefficient; projected (x) represents the projected area per unit length.

[0205] d) Fatigue analysis:

[0206] For critical connection nodes, fatigue life assessments should be performed. Miner's linear cumulative damage theory can be used.

[0207]

[0208] Where: D represents cumulative damage; n i The stress amplitude is σ i The number of loops; N i For stress amplitude σ i The fatigue life is determined by the following condition: when D reaches 1, the structure is considered to have reached its fatigue life.

[0209] Through the detailed equations and function calculation methods described above, the assembly process of steel arch structures can be comprehensively analyzed and optimized, ensuring the safety and stability of the structure during construction and use. This method considers the influence of various factors such as statics, dynamics, temperature, and settlement, providing reliable theoretical guidance for engineering practice.

[0210] The specific implementation method of step S80 is as follows:

[0211] After the arch adjustment and weld acceptance are completed, permanent transverse connectors and tie rods need to be installed to further enhance the overall rigidity of the steel structure.

[0212] First, it is necessary to determine the optimal placement and cross-sectional dimensions A of the connecting components. c This enables it to withstand the horizontal forces and torques that may occur during use. The maximum force F at each connection point can be predicted using finite element analysis. c Based on this, connecting components were designed to withstand these forces.

[0213] During actual installation, machine vision technology is also required to accurately locate the installation positions of the connectors. Automated welding or high-strength bolt fastening is used to complete the connection, ensuring the quality and efficiency of the entire process. A lower limit for the preload force F can be set here. pre,lim Only when the actual applied preload F pre A connection can only be considered reliable if the value exceeds this lower limit.

[0214] In summary, the purpose of step S80 is to further improve the overall rigidity of the entire steel structure by installing permanent lateral connecting members, thereby ensuring safety during subsequent use.

[0215] The specific implementation method of step S90 is as follows:

[0216] After the installation of all permanent connecting components is completed, the temporary support structure needs to be removed to fully complete the ground assembly and arching process of the entire steel structure. During the removal process, it is necessary to first assess the potential temporary stress σ that may occur during the removal process. t and displacement δ t The situation is predicted and analyzed to provide the best demolition sequence and method.

[0217] The following thresholds can be set here:

[0218] 1) Upper limit of stress σ t,lim Real-time monitoring of temporary stress σ t σ should be satisfied t <σ t,lim

[0219] 2) Upper limit of displacement δ t,limReal-time monitoring of temporary displacement δ t δ should be satisfied t <δ t,lim

[0220] After determining the optimal dismantling sequence and method, automated dismantling technology should be employed to quickly and efficiently dismantle the supporting structure. This can be achieved using automated lifting platforms or robotic arms, combined with machine vision technology, to precisely locate and gradually dismantle each supporting component.

[0221] During this process, it is also necessary to continue monitoring the stress on the main structure in real time. If the real-time monitored stress σ or displacement δ is found to exceed the set allowable range σ... lim or δ lim Immediately stop the demolition and make adjustments.

[0222] Once all temporary supports have been safely removed, the entire steel structure ground assembly and arching process is considered complete. By implementing the above steps, the quality and safety of the entire assembly process are ensured, laying a solid foundation for subsequent use.

[0223] In summary, the purpose of step S90 is to quickly and efficiently dismantle the temporary support structure while ensuring the safety of the main structure, and finally complete the ground assembly and arching of the entire steel structure.

[0224] Specifically, the principle of this invention is to make full use of various advanced digital technologies, including digital measurement, structural analysis, and automated control, to achieve precise control and optimization of the construction process.

[0225] Firstly, this method employs digital measurement algorithms and engineering drawing algorithms in the division of the assembly area and the design of temporary support structures. The digital measurement algorithm can quickly and accurately acquire the size and shape information of the assembly area, providing a basis for subsequent support layout; while the engineering drawing algorithm can provide the optimal support component layout scheme based on structural stress analysis, ensuring sufficient support force during the arching process. The application of these algorithms significantly reduces the complexity of the temporary support structure and improves construction efficiency.

[0226] It should be noted that the following are the sources of the parameters involved:

[0227] 1. Geometric parameters:

[0228] L (span): Provided by bridge design drawings, and is usually determined based on factors such as terrain and traffic demand.

[0229] f (sag): Provided by the design drawings, usually determined based on the span ratio (f / L), generally between 1 / 5 and 1 / 8.

[0230] x (coordinate along the span direction): used as an independent variable in the calculation, ranging from 0 to L.

[0231] y (the height coordinate of the arch): calculated using the arch axis equation.

[0232] 2. Load parameters:

[0233] q (uniformly distributed load): includes both dead load and live load.

[0234] Dead load: Consists of the structure's self-weight and additional permanent loads, which can be calculated using material density and structural dimensions.

[0235] Live load: Determined according to bridge design specifications, such as the "General Specifications for Highway Bridge Design" (JTG D60-2015).

[0236] 3. Material properties:

[0237] E (modulus of elasticity): Obtained through material testing or by using standard values, such as 206 GPa for steel.

[0238] ρ (density): Obtained through material testing or by using standard values, such as 7850 kg / m³ for steel. 3 .

[0239] σ yield (Yield strength): Obtained through material testing or using the standard value specified in the design specifications.

[0240] α (coefficient of linear expansion): obtained through material testing or by using standard values, such as 1.2 × 10⁻⁶ for steel. -5 / ℃.

[0241] 4. Cross-sectional properties:

[0242] A(x) (cross-sectional area): provided by the design drawings, and may vary with x.

[0243] I(x) (moment of inertia of the cross section): calculated from the cross section dimensions provided in the design drawings, and may vary with x.

[0244] W(x) (section modulus): calculated by dividing I(x) by the distance from the farthest fiber in the section to the neutral axis.

[0245] 5. Stress analysis parameters:

[0246] N (axial force): Calculated through static analysis.

[0247] M (bending moment): Calculated through static analysis.

[0248] Q (shear force): Calculated through static analysis.

[0249] θ (tangent angle of the arch axis): calculated by the derivative of the arch axis equation: tanθ=y′(x).

[0250] 6. Stress parameters:

[0251] σ min ,σ max (Stress range): Determined by stress calculation formula.

[0252] σ allow (Allowable stress): Determined according to design specifications, usually the yield strength divided by the safety factor.

[0253] 7. Dynamic analysis parameters:

[0254] m (equivalent mass): Calculated by integration, taking into account the actual mass distribution of the arch.

[0255] k (stiffness coefficient): A more accurate value can be obtained through finite element analysis, or it can be estimated using a simplified formula.

[0256] c (damping coefficient): Calculated by estimating the damping ratio.

[0257] ω n (Natural frequency): Calculated using mass and stiffness.

[0258] ζ (damping ratio): Usually estimated based on empirical values, but can be calibrated using measured data.

[0259] 8. Temperature parameters:

[0260] ΔT (temperature change): Determined based on the climate conditions and design specifications of the area where the bridge is located.

[0261] 9. Foundation settlement parameters:

[0262] δ1, δ2 (settlement at both ends): Calculated through geological survey and foundation design, or obtained through on-site monitoring.

[0263] 10. Wind load parameters:

[0264] ρ air (Air density): Approximately 1.225 kg / m³ under standard atmospheric pressure. 3 It can be adjusted according to altitude.

[0265] v (wind speed): Determined based on meteorological data and design specifications for the area where the bridge is located.

[0266] C d (Drag coefficient): Determined through wind tunnel testing or by referring to empirical values ​​of similar structures.

[0267] Aprojected (x) (projected area per unit length): calculated based on the geometry of the arch.

[0268] 11. Fatigue analysis parameters:

[0269] n i (Stress cycle count): Estimated through traffic flow prediction and structural analysis.

[0270] N i (Fatigue life): Determined by the material's SN curve (stress-cycle curve).

[0271] 12. Arch adjustment parameters:

[0272] n (adjustment steps): determined based on engineering experience and required accuracy, usually 10-20 steps.

[0273] m (number of Fourier series terms): Determined based on the required fitting accuracy; usually 5-10 terms are sufficient.

[0274] a k,i ,b k,i (Fourier coefficients): obtained by fitting the error function using the least squares method.

[0275] λ i (Adjust step size factor): Initially set to 1, then adjust according to the optimization algorithm.

[0276] 13. Newmark-β method parameters:

[0277] α, β, γ (Newmark-β parameters): Commonly used values ​​are α = 0.25, β = 0.5, and γ = 0.5.

[0278] Δt (time step): Determined based on the required accuracy and computational efficiency, typically 1 / 10 to 1 / 20 of the natural period.

[0279] 14. Other parameters:

[0280] g (gravitational acceleration): Standard value 9.81 m / s² 2 It can be slightly adjusted according to the geographical location.

[0281] t (time): Used as an independent variable in dynamic analysis.

[0282] Obtaining these parameters and variables involves expertise from multiple fields, including structural mechanics and materials science. Some parameters need to be obtained through laboratory testing or on-site investigation, while others can be derived from design specifications or empirical data. In practical engineering, the accurate determination of these parameters is crucial for ensuring the safety and reliability of the structure.

[0283] Secondly, this method integrates BIM modeling and machine vision technologies during the placement and assembly of steel components. The BIM modeling algorithm can create a 3D digital model of each component and accurately record its positional information, providing a basis for subsequent automated placement and assembly. The machine vision algorithm can identify the actual position and orientation of the components and accurately guide mechanical equipment to complete the positioning and connection of the components. The application of these technologies not only improves the accuracy of placement and assembly but also significantly reduces the risks associated with manual operation.

[0284] In terms of arching control, this method employs both optimization control and feedback control algorithms. The optimization control algorithm can predict the maximum allowable lifting amount and velocity at each stage based on the structure's stress characteristics, thus determining the optimal arching path and velocity curve. The feedback control algorithm, on the other hand, can monitor the structure's displacement and stress state in real time during the arching process and dynamically adjust the parameters of the lifting equipment, ensuring a smooth and controlled process throughout. This precise control method ensures the stability and safety of the structure during arching.

[0285] Finally, in adjusting the arch curve, this method employs a curve fitting algorithm and a structural optimization algorithm. The curve fitting algorithm can reconstruct the mathematical model of the entire arch curve based on the completed arch rib segments; while the structural optimization algorithm can dynamically adjust this model to make it as close as possible to the design requirements. This iterative optimization method not only converges quickly to the target curve but also fully considers the actual stress situation of the structure, ensuring that the adjusted arch meets the strength and performance indicators.

[0286] To better understand and implement this invention, two specific application scenarios of this invention are provided below.

[0287] Example 1: Arching of steel structure ground assembly without considering parameter limitations

[0288] A large stadium project is being constructed using a steel structure, with a total span of 120 meters and a rise of 30 meters. To improve construction efficiency and safety, the project team decided to adopt the steel structure ground assembly and arching method proposed in this invention.

[0289] Optionally, according to the steel structure design specifications, the following requirements apply: Steel beams and steel trusses with a span of 8 meters or more are required to be cambered. For frame beams and trusses connected to frame beams: cambering upwards at mid-span is 1 / 5000 of the span; for secondary beams and trusses not connected to frame columns or hinged at both ends: unless otherwise specified, cambering upwards at mid-span is 1 / 250 of the span. For trusses connected to the tower's outer frame columns, the span of the connecting corridor truss is 45.5m, with a mid-span camber value of 45500 / 500 = 91mm; the span of the variable cross-section beam between trusses is 18m, with a mid-span camber value of 18000 / 500 = 36mm. Cambering should be performed in the direction shown by the arrows below, ensuring the mid-span camber value meets the above requirements. The truss cambering steel supports are made of HW250×250×9×14 Q355 steel and are welded and fixed to the transfer frame steel structure. During assembly, the lower chord truss of the steel connecting corridor is welded to the steel support and pre-arched while being fixed.

[0290] First, based on the design drawings, the project team designated a 120m x 80m ground assembly area. Within this area, they installed 30 temporary support columns, connected laterally by 20 beams, and placed 10 diagonal braces at key locations. The purpose of these temporary support structures is to provide necessary support during subsequent assembly and cambering processes, ensuring the stability of the entire steel structure.

[0291] Next, the project team transported the prefabricated steel components to the assembly area in sections, and used five large cranes to precisely place them in their designed positions. During this process, they utilized BIM modeling technology to digitally model the dimensions, numbering, and location of each component in advance, providing a basis for subsequent precise positioning. Simultaneously, they also developed optimal transportation routes and loading plans to ensure the steel components could be safely and efficiently delivered to the site.

[0292] After placing the components, the project team began assembling the steel structure segment by segment. They started with the arch bases, using high-strength bolts to connect adjacent components. To ensure optimal connection methods at each critical node, they pre-designed optimization algorithms to determine the best connection scheme based on factors such as stress conditions, construction difficulty, and cost-effectiveness. During the actual assembly process, the project team also utilized robotic welding equipment combined with machine vision technology to monitor the position and orientation of components in real time, ensuring connection quality; specific critical nodes include... Figure 2 As shown, Figure 2 Each circled number represents a key node.

[0293] After the splicing was completed, the project team installed temporary horizontal supports and diagonal braces on the main structure. They first used structural analysis algorithms to predict the maximum displacement and stress that the structure might experience during the arching process, and then determined the optimal arrangement of the support components. During the actual installation, the project team used machine vision technology to accurately locate the support positions and used automated tightening equipment to ensure the reliability of the connections.

[0294] After the aforementioned preparatory work, the project team finally began the arching process of the steel structure. They first utilized an optimized control algorithm to develop the optimal phased jacking plan based on the structure's stress characteristics, ensuring that the jacking amount and speed at each stage were within permissible limits. In actual operation, the project team employed four hydraulic jacking devices, combined with a feedback control algorithm, to monitor the structure's displacement and stress state in real time, dynamically adjusting jacking parameters to ensure the entire process was smooth and controlled. Simultaneously, they also used structural analysis algorithms to calculate the stress on the temporary supports during the jacking process in real time, and adjusted the support arrangement and cross-sectional dimensions based on the results.

[0295] After the arching was completed, the project team installed stress monitoring equipment at key nodes to monitor the stress on the entire structure in real time. They first used finite element analysis to predict the stress distribution at key nodes and then employed a sensor layout optimization algorithm to determine the optimal installation locations for the monitoring points. During actual installation, they used machine vision technology to precisely locate the monitoring points and employed automated installation techniques to complete the equipment installation.

[0296] Finally, the project team adjusted the arch curve to ensure it met design requirements. They first used a curve fitting algorithm to reconstruct the mathematical model of the entire arch curve based on the completed arch rib segments. Then, using a structural optimization algorithm, they dynamically adjusted the arch until the overall error was minimized. During this process, they also inspected and verified the weld quality at key nodes to ensure the welding quality met standards.

[0297] Finally, after completing the installation of all permanent connecting components, the project team dismantled the temporary support structure, completing the ground assembly and arching of the entire steel structure. During the dismantling process, they first used structural analysis algorithms to predict potential temporary stresses and displacements, and determined the optimal dismantling sequence. Then, they employed automated dismantling technology to quickly and efficiently complete the removal of the support structure. Throughout this process, they also continued to use stress monitoring algorithms to monitor the stress on the main structure in real time, ensuring that no limits were exceeded during the dismantling process.

[0298] By adopting the steel structure ground assembly and arching method proposed in this invention, the construction efficiency of the steel structure for this large stadium project was significantly improved, and the overall construction period was shortened by three months. Simultaneously, due to the full utilization of digital technology, quality control and safety management throughout the process were greatly enhanced, and no major safety accidents occurred. The project leader stated that this new construction method not only saved a significant amount of labor costs but also provided valuable experience for similar projects in the future.

[0299] Example 2: Arching of Steel Structure Ground Assembly Considering Parameter Limitations

[0300] A large-span highway bridge project is constructed using a steel structure, with a span of 160 meters and a rise of 40 meters. According to design requirements, the bridge needs to withstand vehicle and wind loads, and excessive displacement and stress are not permitted during use. Therefore, the project team decided to adopt the ground-assembly arching method for steel structures proposed in this invention, taking into account relevant parameter limitations.

[0301] First, based on the design drawings, the project team designated a 180m x 90m ground assembly area. Within this area, they installed 40 temporary support columns, connected laterally by 25 beams, and placed 15 diagonal braces at key locations. Through structural analysis algorithms, the cross-sectional dimensions of these temporary support structures were determined to be: columns Φ500×20mm, beams H500×200×10mm, and diagonal braces Φ400×16mm. The arrangement and dimensions of these support components provide sufficient load-bearing capacity during the arching process, ensuring the stability of the entire steel structure.

[0302] Next, the project team transported the prefabricated steel components to the assembly area in sections. Based on BIM modeling analysis, the parameters of each component are as follows:

[0303] Length of component in span direction: L = 10 meters

[0304] Cross-sectional dimensions: H500×300×16mm

[0305] Material: Q345 steel, elastic modulus E = 206 GPa, density ρ = 7850 kg / m³ 3 Yield strength σ yield =345MPa

[0306] Average weight: g s =5.0kN / m

[0307] During the actual placement process, the project team used five large cranes, combined with machine vision algorithms, to precisely place these components in their designed positions. Calculations showed that the average hoisting time for each component was 30 minutes.

[0308] After the components were placed, the project team began assembling the steel structure segment by segment. Based on the design optimization algorithm, high-stress areas such as the arch foot and arch crown were connected by welding, while general areas were connected by high-strength bolts. During the welding process, the project team used robotic welding equipment, combined with real-time monitoring algorithms, to dynamically adjust welding parameters and ensure the quality of each weld was up to standard. For the high-strength bolt connections, automated tightening equipment was used to ensure that the preload met the design requirements based on the bolt material properties.

[0309] After the splicing was completed, the project team installed temporary lateral supports and diagonal braces on the main structure. According to structural analysis, the maximum allowable horizontal displacement during the entire arching process of the 160-meter span bridge does not exceed δ. max =L / 800 = 0.2 meters, the maximum vertical displacement does not exceed To this end, the project team adopted the following support solutions:

[0310] Lateral supports: H600×300×12mm, spacing 10 meters

[0311] Diagonal brace: Φ500×20mm, angle with the column: 30 degrees

[0312] The size and arrangement of these temporary support components can effectively limit the overall horizontal and vertical displacement of the bridge during the arching process, ensuring the stability of the structure.

[0313] During the actual arch raising, the project team first used an optimized control algorithm to determine the following arch raising scheme based on the bridge's stress characteristics: Each lifting height: Δh = 1 meter; Lifting speed: v = 0.5 meters / minute; Lifting force: F max =3000kN.

[0314] Guided by this plan, the project team employed four hydraulic jacking devices, combined with a feedback control algorithm, to monitor the bridge's displacement and stress state in real time during the arching process. Calculations showed that the maximum vertical displacement of the bridge during the entire arching process was 1.8 meters, and the maximum horizontal displacement was 0.16 meters, both within the design limits. Simultaneously, the structural analysis algorithm calculated a maximum compressive stress of 210 MPa and a maximum tensile stress of 180 MPa, which also did not exceed the yield strength of the steel.

[0315] After the arch was erected, the project team installed stress monitoring equipment at nine key nodes, including the arch foot, arch crown, and quarter points. Based on finite element analysis, the stress conditions at these nodes are shown in Table 1 below:

[0316] Table 1 Nodal Stress Table

[0317] Node position Axial force N (kN) Bending moment M (kN·m) Shear force Q (kN) <![CDATA[Maximum stress σ max (MPa)]]> Arch 12500 45000 9000 265 Four points 8000 30000 6500 220 dome 3000 10000 2000 145

[0318] It can be seen that the stress levels at these key nodes did not exceed the yield strength of the steel (345 MPa), and the overall structure was in a safe stress state.

[0319] Finally, the project team used curve fitting and structural optimization algorithms to dynamically adjust the arch curve. First, based on the completed arch rib segments, they reconstructed the mathematical model of the entire arch curve, expressed as: Where L = 160 meters and f = 40 meters.

[0320] Then, using the Fourier series expansion method, the project team made five iterative adjustments to the curve, ultimately reducing the arch error. The area was reduced to less than 5 square meters, meeting the design requirements. During the adjustment process, they also inspected the weld quality at key nodes to ensure that all indicators met the standards.

[0321] After completing the installation of all permanent connections, the project team dismantled the temporary support structure. Based on structural analysis, the maximum permissible self-weight of the bridge during dismantling was q. max =30kN / m, maximum vertical displacement not exceeding δ max = 0.5 meters.

[0322] To address this, the project team employed automated dismantling technology, first removing the top horizontal supports and diagonal braces, and finally dismantling the columns. The entire process took two weeks. During the dismantling, they monitored the bridge's stress and displacement in real time to ensure that all indicators remained within limits.

[0323] By adopting the steel structure ground assembly and arching method proposed in this invention, and with the limitation of relevant parameters, the construction quality and efficiency of this highway bridge project have been significantly improved. The entire steel structure construction cycle has been shortened by 4 months, and costs have been reduced by 8%. At the same time, by fully considering various load conditions that the structure may encounter during use, the long-term safety and reliability of the bridge have been ensured.

[0324] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for assembling and arching a steel structure on the ground, characterized in that, Includes the following steps: S10. According to the design drawings, divide the assembly area on the ground and set up temporary support structures; S20. Transport the steel structure in sections to the assembly area and place them according to the design positions; S30. Starting from the arch foot, steel structure is spliced ​​segment by segment, using high-strength bolts or welding for connection; S40. Install temporary lateral supports and diagonal braces to enhance structural stability; S50. Using hydraulic jacking equipment, gradually lift the arch rib segments while adjusting the temporary support structure. S60. Install stress monitoring equipment at key nodes to monitor the stress on the structure in real time; S70. Complete the arch closure and adjust the arch curve to ensure it meets the design requirements; S80. Install permanent lateral connectors and tie rods to further enhance overall rigidity; S90. Remove the temporary support structure and complete the ground assembly and arching of the steel structure; Step S70 specifically includes: after the arch closure is completed, the entire arch curve is adjusted to ensure that it meets the design requirements; firstly, a curve fitting method is used to reconstruct the mathematical model of the entire arch curve based on the completed arch rib segments; then, the arch curve is dynamically adjusted to make it as close as possible to the design requirements; after the arch closure is completed, the welds of key nodes also need to be inspected and verified to ensure that the welding quality meets the standards.

2. The method for assembling and arching a steel structure on the ground according to claim 1, characterized in that, Step S10 specifically includes: dividing the area on the ground for steel structure assembly according to the design drawings, and setting up a structure for temporary support in the area. When dividing the assembly area, the length, width and height parameters of the area are measured and determined by digital measurement method. When setting up the temporary support structure, the layout scheme of the support components is designed by engineering drawing software, including the position, cross-sectional size and connection method of the support components, to ensure that the necessary support force is provided in the subsequent assembly process.

3. The method for assembling and arching a steel structure on the ground according to claim 2, characterized in that, Step S20 specifically includes: transporting the prefabricated steel structure components in sections to the assembly area and placing them in designated positions according to design requirements. In this process, BIM modeling method is first used to create a three-dimensional model of each component and mark its number, size and position information; after being transported to the assembly area, the components are accurately placed in the design position.

4. The method for assembling and arching a steel structure on the ground according to claim 3, characterized in that, Step S30 specifically includes: starting from the arch foot, splicing and connecting the steel structure segment by segment using high-strength bolts or welding. When determining the connection method for each key node, it is necessary to comprehensively consider the structural stress, construction difficulty, or economic factors to provide the optimal connection scheme. In the actual splicing process, it is necessary to use existing robotic welding or automated bolt installation equipment, combined with existing machine vision methods, to identify and adjust the position and posture of the components to ensure connection quality. At the same time, it is also necessary to use real-time detection of the component stress state and dynamically adjust the welding parameters or bolt preload to avoid exceeding limits.

5. The method for assembling and arching a steel structure on the ground according to claim 4, characterized in that, Step S40 specifically includes: after the steel structure splicing is completed, temporary lateral supports and diagonal braces are installed to enhance the stability of the entire structure; firstly, the maximum displacement and stress that may occur in the arch structure during the arching process are predicted; then, the optimal arrangement position, cross-sectional size and connection method of the temporary support components are determined so that the entire structure can maintain sufficient stability during the arching process.

6. The method for assembling and arching a steel structure on the ground according to claim 5, characterized in that, Step S50 specifically includes: using hydraulic jacking equipment to gradually lift the arch rib segments to complete the arching process of the entire steel structure; firstly, based on the stress characteristics of the arch structure, the maximum allowable lifting amount and speed at each stage need to be calculated, and the optimal lifting path and speed need to be determined; during the actual lifting process, the displacement and stress state of the structure need to be monitored in real time, and the parameters of the hydraulic equipment need to be dynamically adjusted to ensure that the lifting process is stable and controlled; at the same time, the stress situation of the temporary supports during the lifting process also needs to be calculated in real time, and the arrangement and cross-sectional dimensions of the supports need to be adjusted.

7. The method for assembling and arching a steel structure on the ground according to claim 6, characterized in that, Step S60 specifically includes: installing stress monitoring equipment at key nodes to monitor the stress of the entire steel structure in real time; firstly, the stress distribution of key nodes needs to be predicted using finite element analysis to determine the key monitoring locations; then, the optimal installation location and number of monitoring devices are calculated; during actual installation, machine vision is used to accurately locate the monitoring points, and automated installation technology is used to complete the installation of the equipment.

8. The method for assembling and arching a steel structure on the ground according to claim 7, characterized in that, Step S80 specifically includes: installing permanent lateral connectors and tie rods to further enhance the overall rigidity of the entire steel structure; firstly, it is necessary to determine the optimal arrangement position and cross-sectional dimensions of the connecting components so that they can withstand the horizontal forces and torques that may occur during the use phase; in actual installation, it is also necessary to use machine vision methods to accurately position the connectors and adopt automated welding or high-strength bolt fastening technology to ensure reliable connection.

9. A method for assembling and arching a steel structure on the ground according to claim 8, characterized in that, Step S90 specifically includes: after completing the installation of all permanent connecting components, dismantling the temporary support structure to fully complete the ground assembly and arching process of the entire steel structure; during the dismantling process, it is necessary to first predict and analyze the temporary stress and displacement that may occur during the dismantling process, and give the best dismantling sequence and method; then, use automated dismantling technology to quickly and efficiently complete the dismantling of the support structure; during this process, it is also necessary to continue to monitor the stress of the main structure in real time, and if it is found to exceed the allowable range, the dismantling should be stopped immediately and adjustments should be made.

Images