Accurate control method for angle of bifurcated column

Abstract

The invention provides a bifurcated column angle accurate control method, and belongs to the technical field of building construction.According to the bifurcated column angle accurate control method, a total station is used for conducting high-precision three-dimensional lofting to achieve preliminary positioning, and an adjustable pull rod and an angle deviation correction equation are adopted for accurate adjustment in the installation process; the stability of the formwork is ensured through a steel back ridge reinforcing system and a supporting rigidity evaluation equation, the layout of monitoring nodes is optimized through a high-definition intelligent monitoring and measuring integrated device and a minimum dominating set algorithm based on the graph theory, and real-time angle data are obtained through a multi-sensor fusion measuring system. A space-time alignment algorithm and a Kalman filtering algorithm are used for data processing, an angle stability evaluation equation is established to judge the control precision, and a dynamic adjustment control equation is used for continuously monitoring and adjusting a supporting system in the concrete pouring process. The technical problem that the angle control precision is insufficient in the construction process of the hyperbolic variable cross-section concrete bifurcated column is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of building construction, and in particular relates to a method for accurately controlling the angle of a bifurcated column. Background Art

[0002] Hyperbolic variable-section concrete bifurcated columns, as important components in modern building structures, are widely used in complex construction projects such as large-span spatial structures, stadiums, and convention centers. Their unique hyperbolic shape and bifurcated structure can effectively transfer loads and achieve architectural aesthetics. Traditional bifurcated column construction relies primarily on empirical estimation and simple measuring tools for angle control. Conventional steel formwork support systems and manual adjustment methods are used, with on-site positioning and angle correction performed by construction workers using visual inspection and basic measuring equipment such as levels and theodolites. Traditional construction methods have significant drawbacks in angle control. Due to the complex structure of bifurcated columns, large cantilever spans, and frequent changes in construction loads, traditional manual measurement and empirical adjustment methods struggle to achieve high-precision angle control. Measurement errors and human factors lead to accumulated angle deviations. Formwork deformation and insufficient support system rigidity during construction further exacerbate the difficulty of angle control. In today's complex building construction, traditional techniques are unable to meet the stringent requirements for angle precision in bifurcated columns due to their complex geometry, demanding construction techniques, and the coordination of multiple spatial dimensions involved in angle control. Angle deviations can directly impact the structural performance and overall building quality, potentially posing a safety hazard. This means that existing techniques for constructing hyperbolic variable-section concrete bifurcated columns suffer from insufficient angle control accuracy. Summary of the Invention

[0003] In view of this, the present invention provides a method for accurately controlling the angle of a bifurcated column, which can solve the technical problem of insufficient angle control accuracy during the construction of a hyperbolic variable-section concrete bifurcated column in the prior art.

[0004] The application is achieved as follows: the application provides a bifurcated column angle accurate control method, which performs three-dimensional modeling on a hyperbolic variable cross-section concrete bifurcated column to obtain a bifurcated column overhanging length, a bending curvature, and a designed bifurcated angle, and constructs a bifurcated column three-dimensional positioning model; a steel formwork system model is constructed based on the bifurcated column three-dimensional positioning model, the steel elastic modulus, the cross-section moment of inertia, and the support length are obtained, and a standard formwork module configuration scheme is determined; a total station is used to perform high-precision three-dimensional lofting to obtain formwork positioning coordinates for preliminary positioning; adjustable pull rods are used for temporary positioning and support when installing a bifurcated column overhanging section bottom formwork, an angle correction value is calculated through an angle deviation correction equation, and positioning parameters are adjusted; a steel back rafter reinforcement system is used in the bifurcated column main column side formwork installation process, a support stiffness value is calculated using a support stiffness evaluation equation to determine the stability of the support system; the steel formwork system is detected using three-dimensional positioning checking technology, measured angle data and angle deviation amounts are obtained through an intelligent monitoring and measuring integrated device, an angle stability evaluation equation is established to calculate an angle stability factor to determine the angle control precision; the formwork system deformation and displacement are monitored during the concrete pouring process, an angle change rate is obtained through a data acquisition device, and a support force adjustment amount is calculated using a dynamic adjustment control equation to adjust the support system to ensure the angle precision.

[0005] The bifurcated column with a hyperbolic variable cross-section is specifically a concrete column body with a hyperboloid shape and a cross-section that changes along the height direction, and two or more overhanging branch structures are formed at the bifurcated position.

[0006] The bifurcated column three-dimensional positioning model is constructed by outputting the bifurcated column overhanging length and the designed bifurcated angle as the on-site three-dimensional lofting reference, and the steel formwork system model is constructed by performing modular design and checking and generating digital processing drawings.

[0007] The high-precision three-dimensional lofting is performed by setting the bifurcated column main column bottom and the overhanging section plane projection points as plane control points and the bifurcated top and the beam plate connection elevation as vertical control points for preliminary positioning.

[0008] The bifurcated column overhanging section bottom formwork is installed by using an upright rod to support the formwork bottom channel steel, and the angle deviation correction equation inputs the bifurcated column overhanging length, the designed bifurcated angle, the environmental temperature coefficient, the material elastic modulus, and the cross-section moment of inertia.

[0009] The steel back rafter reinforcement system is used by setting the reinforcement spacing to 1000 mm, temporarily setting a pull rod support at each cross-section, setting a double pull rod between the two overhanging bifurcated columns, and inputting the steel elastic modulus, the cross-section moment of inertia, the support length, the constraint condition coefficient, and the temperature influence coefficient into the support stiffness evaluation equation.

[0010] The step of detecting by adopting the three-dimensional positioning checking technology is specifically full-range detection and angle stability evaluation equation input angle deviation, design reference angle, time variable, damping coefficient, and system response time constant for the installed steel formwork system.

[0011] The step of monitoring during the concrete pouring process is specifically continuous formwork system deformation and displacement monitoring, dynamic adjustment control equation input angle deviation, angle change rate, integral time constant, proportional coefficient, and differential coefficient.

[0012] The intelligent monitoring and measurement integrated device is specifically a monitoring equipment integrating measurement sensors and image recognition technology, and is used for real-time collection of bifurcated column geometric parameters and deformation data.

[0013] The method for determining the key monitoring nodes is specifically constructing a node graph network based on a bifurcated column three-dimensional positioning model, taking bifurcated column geometric feature points as graph nodes and structure connection relationships as graph edges, and selecting key monitoring nodes from the node graph network by using a minimum dominating set algorithm to ensure that all key geometric features of the bifurcated column are covered by the least number of nodes.

[0014] The adjustable pull rod is specifically a support component made of a 38mm diameter threaded steel pipe, with an adjustment range of ±50mm, and is used for formwork positioning and temporary support. The steel back rib is specifically a formwork support component made of a 8cm high steel grid, which is welded to the back of the formwork to enhance the rigidity and stability of the formwork.

[0015] The intelligent monitoring and measurement integrated device verifies the integrity and redundancy of the key monitoring node layout through connectivity analysis in graph theory, arranges multiple point laser ranging sensors at the key monitoring node positions, obtains measured angle data through three-dimensional coordinate measurement, configures a high-resolution industrial camera for visual auxiliary measurement, and adopts a sub-pixel level image processing algorithm to identify the position changes of bifurcated column edge feature points. The intelligent monitoring and measurement integrated device fuses multiple sensor data through a space-time alignment algorithm, eliminates measurement time difference and space coordinate system deviation, establishes a unified space-time reference coordinate system, adopts a Kalman filtering algorithm for noise reduction processing of measurement data, removes environmental vibration and equipment noise interference, reduces single-point measurement error through multiple-point redundant measurement and data cross-validation, sets a measurement accuracy threshold for real-time error monitoring, and automatically starts a calibration program when the measurement error exceeds the set threshold, to ensure that the angle measurement accuracy is controlled within 0.1 degrees.

[0016] Wherein, the environmental temperature coefficient is calculated according to the material thermal expansion and contraction characteristics by collecting the environmental temperature in real time through the field temperature sensor, the material elastic modulus is obtained by the standard value of the steel material quality detection report, the constraint condition coefficient is determined according to the support end connection mode and the boundary condition, the temperature influence coefficient is calculated through the field temperature monitoring data and the material thermal deformation parameters, the design reference angle is derived from the obtained design bifurcation angle, the time variable is obtained by recording the real-time clock in the construction process, the damping coefficient is determined according to the material damping characteristics and the structure damping characteristics of the steel formwork system, and the system response time constant is calculated through the support system dynamics analysis.

[0017] Wherein, the integral time constant is set according to the response characteristics and control accuracy requirements of the angle control system, the proportional coefficient is determined according to the linear relationship between the angle deviation and the support force adjustment, the differential coefficient is determined according to the influence degree of the angle change rate on the support force adjustment, the angle deviation correction equation is improved based on the elastic deformation theory in structural mechanics and combined with the cantilever characteristics of the bifurcated column, the output angle correction value is used to guide the on-site positioning adjustment, the support stiffness evaluation equation is improved based on the Euler buckling theory and combined with the characteristics of the steel back rafter support system, the output support stiffness value is used to judge the bearing capacity of the support system, the angle stability evaluation equation is improved based on the control system stability theory and combined with the angle control requirements of the bifurcated column, the output angle stability factor is used to evaluate the angle control accuracy, and the dynamic adjustment control equation is improved based on the PID control theory and combined with the characteristics of the formwork support system, and the output support force adjustment is used to adjust the support system in real time.

[0018] The bifurcated column angle accurate control system is established by adopting the comprehensive technical scheme combining three-dimensional modeling, parameterized design, high-precision measurement and intelligent control, accurate geometric parameters and design reference are obtained through digital modeling technology, the rigidity and stability of the formwork system are ensured by using parameterized formwork design, and real-time angle monitoring and deviation analysis are realized by using high-precision three-dimensional measurement technology. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1is a flow chart of the method of the present invention.

[0020] Figure 2 This is the installation diagram of the bifurcated column in Example 2. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0022] like Figure 1 FIG. 1 is a flow chart of a method for accurately controlling the angle of a bifurcated column provided by the present invention. The method comprises the following steps:

[0023] S01. Use Rhino surface modeling technology to perform three-dimensional modeling of a hyperbolic variable-section concrete bifurcated column, obtain the bifurcated column cantilever length, arc curvature, and designed bifurcated angle, construct a three-dimensional positioning model of the bifurcated column, and output the bifurcated column cantilever length and the designed bifurcated angle as a benchmark for on-site three-dimensional lofting;

[0024] S02. Based on the bifurcated column 3D positioning model, use SolidWorks parametric design technology to build a steel formwork system model, obtain the steel elastic modulus, section moment of inertia, and support length, perform modular design and verification, determine the standard formwork module configuration plan, and generate digital processing drawings;

[0025] S03. Use a total station to perform high-precision 3D layout at the construction site to obtain template positioning coordinates. Set the bottom of the bifurcated column and the plane projection point of the cantilever section as the plane control point, and the elevation of the bifurcated top and the beam-slab connection as the vertical control point for preliminary positioning;

[0026] S04. When installing the bottom formwork of the cantilevered section of the bifurcated column, use vertical poles to support the bottom channel steel of the formwork, and use adjustable tie rods for temporary positioning and support. Use the angle deviation correction equation to input the cantilever length of the bifurcated column, the designed bifurcated angle, the ambient temperature coefficient, the material elastic modulus, and the section moment of inertia to calculate the angle correction value and adjust the positioning parameters.

[0027] S05. During the installation of the side formwork for the bifurcated columns and main columns, a steel back rib reinforcement system is used. The reinforcement spacing is set to 1000mm. Temporary tie rod supports are installed at each section. Double tie rods are installed between the two cantilevered bifurcated columns. The support stiffness evaluation equation is used to input the steel elastic modulus, the section moment of inertia, the support length, the constraint condition coefficient, and the temperature influence coefficient to calculate the support stiffness value and determine the stability of the support system.

[0028] S06. Conduct a comprehensive inspection of the installed steel formwork system using three-dimensional positioning and verification technology. Obtain measured angle data and angle deviation using a high-definition intelligent monitoring and measurement integrated device. Establish an angle stability evaluation equation by inputting the angle deviation, design reference angle, time variable, damping coefficient, and system response time constant to calculate the angle stability factor and determine the angle control accuracy.

[0029] S07. During the concrete pouring process, the deformation and displacement of the formwork system are continuously monitored, the angle change rate is obtained through the data acquisition device, and the dynamic adjustment control equation is used to input the angle deviation, the angle change rate, the integral time constant, the proportional coefficient, and the differential coefficient to calculate the support force adjustment amount and adjust the support system in time to ensure the angle accuracy.

[0030] Among them, the hyperbolic variable-section concrete bifurcated column refers to a concrete column with a hyperbolic shape and a cross-section that changes along the height direction, forming two or more cantilevered branch structures at the bifurcation position.

[0031] The Rhino surface modeling technology is a three-dimensional modeling software technology based on NURBS surfaces, which is used to create and edit three-dimensional surface geometric models.

[0032] The SolidWorks parametric design technology is a feature-based three-dimensional design software technology that realizes automatic updating and optimized design of models through parameter drive.

[0033] The adjustable pull rod is a supporting member made of a 38mm diameter threaded steel pipe with an adjustment range of ±50mm, and is used for template positioning and temporary support.

[0034] The steel back rib is a formwork support component made of 8cm high steel grid, which is welded to the back of the formwork to enhance the rigidity and stability of the formwork.

[0035] The intelligent monitoring and measurement integrated device adopts a high-definition intelligent monitoring and measurement integrated device, specifically a monitoring device that integrates high-precision measurement sensors and image recognition technology, and is used to collect the geometric parameters and deformation data of the bifurcation column in real time. First, a node graph network is constructed based on the three-dimensional positioning model of the bifurcation column, and the geometric feature points of the bifurcation column are used as graph nodes, and the structural connection relationship is used as the graph edge. The minimum dominating set algorithm is used to select key monitoring nodes from the node graph network to ensure that all key geometric features of the bifurcation column are covered with the minimum number of nodes. The integrity and redundancy of the layout of the key monitoring nodes are verified through the connectivity analysis in graph theory. Multi-point laser ranging sensors are deployed at the positions of the key monitoring nodes. Through the three-dimensional coordinate The measured angle data is obtained by measurement, and a high-resolution industrial camera is configured for visually assisted measurement. A sub-pixel image processing algorithm is used to identify the position changes of the edge feature points of the bifurcation column. The multi-sensor data is fused and processed through a spatiotemporal alignment algorithm to eliminate the measurement time difference and the spatial coordinate system deviation, and a unified spatiotemporal reference coordinate system is established. The Kalman filter algorithm is used to reduce the noise of the measurement data to remove environmental vibration and equipment noise interference. The single-point measurement error is reduced through multi-point redundant measurement and data cross-validation. A measurement accuracy threshold is set for real-time error monitoring. When the measurement error exceeds the set threshold, the calibration procedure is automatically started to ensure that the angle measurement accuracy is controlled within 0.1 degrees.

[0036] The ambient temperature coefficient is obtained by collecting the ambient temperature in real time through an on-site temperature sensor and calculating it based on the thermal expansion and contraction characteristics of the material. The elastic modulus of the material obtains the standard value through the steel material test report. The constraint condition coefficient is determined based on the support end connection method and boundary conditions. The temperature influence coefficient is calculated based on on-site temperature monitoring data and material thermal deformation parameters. The design reference angle is derived from the design bifurcation angle obtained in step S01. The time variable is obtained through real-time clock recording during the construction process. The damping coefficient is determined based on the material damping characteristics and structural damping characteristics of the steel formwork system. The system response time constant is calculated through dynamic analysis of the support system. The integral time constant is set according to the response characteristics and control accuracy requirements of the angle control system. The proportional coefficient is determined based on the linear relationship between the angle deviation and the support force adjustment amount. The differential coefficient is determined based on the degree of influence of the angle change rate on the support force adjustment.

[0037] The angle deviation correction equation is based on the elastic deformation theory in structural mechanics and is improved in combination with the cantilever characteristics of the bifurcated column. The angle correction value is output to guide the on-site positioning adjustment in step S04.

[0038] The support stiffness evaluation equation is based on Euler buckling theory and is improved in combination with the characteristics of the steel back rib support system. The output support stiffness value is used to determine the bearing capacity of the support system in step S05.

[0039] The angle stability evaluation equation is improved based on the control system stability theory combined with the angle control requirements of the bifurcated column, and outputs the angle stability factor for evaluating the angle control accuracy in step S06.

[0040] The dynamic adjustment control equation is improved based on the PID control theory combined with the characteristics of the template support system, and outputs the support force adjustment amount for real-time adjustment of the support system in step S07.

[0041] The node graph network is a network structure based on graph theory, used to represent the topological relationship between the geometric feature points of the bifurcated column.

[0042] The minimum dominating set algorithm is an optimization algorithm in graph theory for finding the minimum node set, so that each node in the network is adjacent to at least one node in the dominating set or belongs to the dominating set.

[0043] The key monitoring node is an important location point for installing measurement sensors selected by the minimum dominating set algorithm.

[0044] The space-time alignment algorithm is a data fusion algorithm for eliminating multi-sensor time synchronization errors and spatial coordinate system deviations.

[0045] The Kalman filter algorithm is a recursive filtering algorithm used to estimate the system state from noisy observation data.

[0046] The specific implementation of the above steps is described in detail below.

[0047] The specific implementation of step S01 is to first establish a three-dimensional coordinate system, taking the center point of the bifurcated column bottom as the origin, and establish a rectangular coordinate system. The non-uniform rational B-spline surface modeling technology is used to construct a digital three-dimensional model of the hyperbolic variable cross-section concrete bifurcated column. The hyperboloid shape is defined by the control point grid, and the surface control parameters including the surface order, node vector and weight factor are set to ensure that the surface continuity and smoothness meet the architectural design requirements. According to the design drawings, the geometric parameters of the bifurcated column are input, including the main column bottom cross-section size, top bifurcation cross-section size, bifurcation angle and cantilever length. The hyperbolic variable cross-section column entity model is generated using the surface lofting command. The cantilever length value of the bifurcated column is extracted by the measurement tool, the bending curvature radius is calculated using the curvature analysis function, and the design bifurcation angle value is obtained using the angle measurement tool. When establishing the three-dimensional positioning model of the bifurcated column, the conversion relationship between the global coordinate system and the local coordinate system is set, and the spatial coordinates of the key control points are defined, including the center point of the main column bottom, the bifurcation point position and the cantilever end position. A three-dimensional positioning data file is generated as the reference data for field construction. The purpose of this step is to provide accurate geometric reference for subsequent steel template design and field construction.

[0048] The specific implementation of step S02 involves importing the three-dimensional positioning model data of the bifurcated column obtained in step S01 into parametric three-dimensional design software, and using feature-based modeling technology to construct a digital model of the steel formwork system. A parameter-driven design approach establishes a correlation between formwork dimensions and bifurcated column geometric parameters, enabling the formwork to adapt to changes in the bifurcated column's shape. Standard values ​​for the steel elastic modulus are obtained from steel material inspection reports, the section moment of inertia is calculated through cross-sectional geometry, and the support length parameters are measured to determine the support length parameters. Using a modular design concept, the complex bifurcated column formwork is decomposed into standardized formwork modules, including the main column section formwork, the bifurcated transition section formwork, and the cantilever section formwork. Each module has standardized connection interfaces and positioning datums. When verifying the formwork's bearing capacity, the combined effects of concrete pouring lateral pressure, the formwork's deadweight, and construction loads are considered, and finite element analysis is used to verify that the formwork's strength and rigidity meet regulatory requirements. After determining the standard formwork module configuration, digital processing drawings are generated, including detailed dimensions, material specifications, and processing techniques. The purpose of this step is to achieve standardized design and precise processing of the formwork system.

[0049] The specific implementation method of step S03 is to establish a measurement control network at the construction site, set benchmarks and checkpoints, and use a high-precision total station to perform three-dimensional coordinate measurement and layout work. First, the instrument is calibrated and the coordinate system is established to ensure that the measurement accuracy meets the engineering requirements and the measurement accuracy is controlled within the millimeter level. According to the three-dimensional positioning model data of the bifurcation column output in step S01, the theoretical coordinate values ​​of each key point in the on-site coordinate system are calculated. The design coordinates are converted into construction site coordinates using a coordinate conversion algorithm, taking into account the influence of factors such as the earth's curvature and atmospheric refraction. The template positioning coordinates are obtained through the distance and angle measurement functions of the total station. When establishing the plane control network, the center point of the bottom of the bifurcation column main column and the plane projection point of the cantilever section are set as plane control points, and the triangulation method is used to ensure plane positioning accuracy. When establishing the vertical control network, the elevation of the bifurcation column top and the beam-slab junction is set as the vertical control point, and the leveling method is used to ensure vertical positioning accuracy. The measurement accuracy is verified by checking the closure error. When the closure error exceeds the limit, re-measurement is required. The plane closure error is controlled within 5mm, and the elevation closure error is controlled within 3mm. The purpose of this step is to provide an accurate spatial positioning reference for template installation.

[0050] The specific implementation of step S04 involves installing the bottom formwork for the cantilever section of the bifurcated column and setting up a temporary support system based on the formwork positioning coordinates obtained in step S03. First, the support system is installed, using steel pipe poles to support the bottom channel steel of the formwork. The pole spacing is set at 1200mm, and pads are placed at the bottom to ensure stable support. When installing the adjustable tie rods, support members made of 38mm diameter threaded steel pipe are used. Through threaded connections, an adjustment range of ±50mm is achieved, which serves as temporary positioning and support for the formwork. A calculation model for angle deviation correction is established. This model is based on the elastic deformation theory in structural mechanics and considers the deformation characteristics of cantilever structures under deadweight and external loads. Input parameters include the cantilever length of the bifurcated column, the designed bifurcated angle, the ambient temperature coefficient, the material elastic modulus, and the section moment of inertia. The angle correction value is calculated using deformation coordination conditions and equilibrium equations. The ambient temperature coefficient is calculated based on the thermal expansion and contraction coefficient of steel using real-time ambient temperature measurements collected by on-site temperature sensors. A 1°C temperature change corresponds to an angle correction value of approximately 0.02 degrees. Adjust the length of the adjustable tie rod according to the calculated angle correction value to achieve precise positioning of the formwork. The purpose of this step is to ensure that the spatial position and angle of the cantilever section formwork meet the design requirements.

[0051] The specific implementation of step S05 involves constructing a steel back-rib reinforcement system during the installation of the bifurcated column main column side formwork to improve the overall stiffness and stability of the formwork. The steel back-rib components are constructed using 8cm-high steel gratings and secured to the back of the formwork via welding. The reinforcement spacing is uniformly set at 1000mm to ensure continuous load transfer. Temporary tie rods are installed at each cross-section, connected using high-strength bolts, with the preload controlled to above 80% of the design value. Double tie rods are installed between the two cantilevered bifurcated columns to form a stable triangular support structure, enhancing overall resistance to lateral deformation. A support stiffness assessment calculation model is established based on Euler buckling theory and improved incorporating the structural characteristics of the steel back-rib support system. Input parameters include the steel elastic modulus, section moment of inertia, support length, constraint coefficient, and temperature influence coefficient. Support stiffness is calculated using buckling analysis. The constraint coefficient is determined based on the connection method of the support ends, with a value of 1.0 for fixed constraints and 0.8 for hinged constraints. The temperature influence coefficient is calculated based on on-site temperature fluctuations and steel thermal deformation parameters. When the calculated support stiffness value is greater than 1.2 times the design requirement, the support system is judged to have sufficient bearing capacity and stability. The purpose of this step is to ensure that the formwork support system remains stable during the concrete pouring process.

[0052] The specific implementation of step S06 involves using a high-definition intelligent monitoring and measurement integrated device to conduct comprehensive geometric inspection and angular accuracy verification on the installed steel formwork system. First, a node graph network structure is constructed based on the three-dimensional positioning model of the bifurcated column. Key geometric feature points of the bifurcated column are defined as graph nodes, and structural connections are defined as graph edges, forming a complete topological network. A minimum dominating set algorithm is used to select key monitoring nodes from the node graph network. This algorithm uses a greedy strategy and heuristic search to cover all key geometric features of the bifurcated column with the minimum number of nodes. The number of monitoring nodes typically accounts for 20% to 30% of the total number of feature points. The integrity of the key monitoring node layout is verified through connectivity analysis based on graph theory, ensuring that any feature point can be indirectly measured through the monitoring nodes. A certain level of redundancy is also provided to mitigate single-point failures. Multi-point laser ranging sensors are deployed at the selected key monitoring node locations, achieving a measurement accuracy of 0.1 mm. Measured angle data is obtained through three-dimensional coordinate measurement. A high-resolution industrial camera is deployed for visually assisted measurement, and a sub-pixel image processing algorithm is used to identify positional changes in feature points along the bifurcated column edges, achieving an image processing accuracy of 0.05 pixels. A spatiotemporal alignment algorithm is used to fuse multi-sensor data, eliminating measurement time differences and spatial coordinate system deviations between different sensors and establishing a unified spatiotemporal reference coordinate system. A Kalman filter algorithm is used to reduce noise in the measured data, removing interference from environmental vibration and equipment noise. The filtered data accuracy is improved by over 30%. An angle stability evaluation calculation model is established. This model is based on control system stability theory. Input parameters include angle deviation, design reference angle, time variable, damping coefficient, and system response time constant. An angle stability factor is calculated to assess angle control accuracy. When the angle stability factor is greater than 0.95, the angle control accuracy is determined to meet the requirements. The measurement accuracy threshold is set to 0.1 degrees. The purpose of this step is to verify the geometric accuracy of the template installation and the angle control effect.

[0053] The specific implementation of step S07 is to establish a real-time monitoring system for the deformation and displacement of the formwork system during concrete pouring, and to use a dynamic adjustment control strategy to ensure the angle accuracy. The angle change data is continuously collected by a data acquisition device, with a sampling frequency of 1 Hz, and the angle change rate parameter is obtained for dynamic analysis. A dynamic adjustment control calculation model is established, which is based on the proportional-integral-derivative control theory and optimized in combination with the dynamic characteristics of the formwork support system. The input parameters include the angle deviation, the angle change rate, the integral time constant, the proportional coefficient and the differential coefficient, and the support force adjustment amount is calculated by the control algorithm. The proportional coefficient is determined according to the linear relationship between the angle deviation and the support force adjustment amount, and the typical value is 0.8 to 1.2. The integral time constant is set according to the response characteristics of the angle control system, and the typical value is 5 to 10 seconds. The differential coefficient is determined according to the influence of the angle change rate on the support force adjustment, and the typical value is 0.1 to 0.3. When the calculated support force adjustment amount exceeds ±5% of the design value, the length of the adjustable pull rod is adjusted by the hydraulic jack or manual screw rod to realize the real-time adjustment of the support system. An early warning mechanism is established, and when the angle deviation exceeds 0.2 degrees or the angle change rate exceeds 0.1 degrees per minute, the system automatically sends a warning signal to remind the operator to take timely adjustment measures. The purpose of this step is to dynamically maintain the angle accuracy of the bifurcated column during concrete pouring.

[0054] The key technical ideas of the present application mainly include intelligent monitoring node optimization layout technology based on graph theory, high-precision angle measurement technology of multi-sensor fusion, and angle accuracy maintenance technology of dynamic closed-loop control.

[0055] The intelligent monitoring node optimization layout technology based on graph theory abstracts the geometric characteristics of the bifurcated column as a node graph network, and uses the minimum dominating set algorithm to realize intelligent optimization of the monitoring point positions. Compared with the traditional empirical layout method, this technology can achieve the maximum monitoring coverage with the least monitoring equipment, avoiding the problems of monitoring blind area and equipment redundancy. Through connectivity analysis, the integrity and robustness of the monitoring network are ensured, and when individual monitoring points fail, the system can still maintain effective monitoring capability. This technology reduces the number of monitoring devices to about 30% of the traditional method, while improving the monitoring efficiency and reliability.

[0056] The high-precision angle measurement technology of multi-sensor fusion combines laser ranging sensors and high-resolution industrial cameras to realize collaborative measurement of multi-source data through space-time alignment algorithm and Kalman filter processing. Compared with single sensor measurement method, this technology significantly improves the measurement accuracy and reliability through multi-sensor redundancy and data cross-validation. Laser ranging provides high-precision distance information, and industrial cameras provide rich visual feature information. After fusion, the angle measurement accuracy can be within 0.1 degrees, which is more than 50% higher than the traditional measurement method.

[0057] Dynamic closed-loop control's angle accuracy maintenance technology, based on proportional-integral-differential control theory, establishes a dynamic response model between angle deviation and support force adjustment. Compared to static control methods, this technology can respond in real time to various disturbances during the construction process, maintaining angle accuracy stability through continuous feedback adjustment. The system also features predictive capabilities, enabling proactive adjustments based on angle trends to prevent cumulative angular deviations.

[0058] The synergistic effect of these key technologies forms a complete system for precise control of bifurcated column angles. Graph optimization technology provides the optimal monitoring network foundation for high-precision measurement, multi-sensor fusion technology provides accurate feedback information for dynamic control, and dynamic closed-loop control technology implements precise adjustment actions based on measurement feedback. The three work together to form a complete closed loop from monitoring planning, precise measurement, to dynamic control, achieving precise control of bifurcated column angles throughout the entire process. Compared to traditional open-loop control methods, this collaborative technology system improves angle control accuracy several times while also possessing adaptive and self-correcting capabilities, significantly improving the quality control level of complex structural construction.

[0059] It should be noted that the present invention also solves the following technical problems: First, the difficulty in assessing the stability of the bifurcated column formwork support system. Traditional construction lacks a scientific support stiffness assessment method, and support parameters are often determined based on experience, resulting in an increased risk of formwork deformation and instability. The present invention establishes a support stiffness assessment equation based on Euler buckling theory, combines key parameters such as steel elastic modulus, section moment of inertia, and support length, scientifically calculates the support stiffness value and assesses the bearing capacity, thereby ensuring the stability and safety of the formwork support system. Second, the technical problem of the difficulty in fusing and processing multi-sensor measurement data during bifurcated column construction. Due to the complex geometry of the bifurcated column, the large number of measurement points, and the diverse sensor types, traditional methods have difficulty in effectively fusing measurement data from different sensors, resulting in time synchronization errors and spatial coordinate deviations. The present invention eliminates multi-sensor time differences and spatial coordinate system deviations by adopting a spatiotemporal alignment algorithm, establishes a unified spatiotemporal reference coordinate system, applies a Kalman filter algorithm to reduce noise on the measurement data, and improves measurement reliability through multi-point redundant measurement and data cross-validation, achieving high-precision multi-sensor data fusion. Finally, there is the technical problem of the lack of dynamic adjustment control algorithm for the bifurcation column angle. Traditional construction lacks real-time angle adjustment control methods, and it is impossible to adjust the support force in time according to the angle changes. The present invention establishes a dynamic adjustment control equation based on PID control theory. By inputting real-time data such as angle deviation and angle change rate, the support force adjustment amount is calculated and the support system is adjusted in time, thereby realizing dynamic and precise control of the bifurcation column angle.

[0060] Specifically, the principle of the present invention is as follows: The core principle of the technical solution of the present invention, which can solve the problem of insufficient angle control accuracy of hyperbolic variable-section concrete bifurcation columns, lies in the establishment of a closed-loop angle control system based on digital modeling, intelligent measurement and dynamic control. First, an accurate three-dimensional geometric model is constructed through Rhino surface modeling technology to obtain the accurate geometric parameters and design reference angle of the bifurcation column, providing a reliable data basis for subsequent angle control and avoiding the systematic errors caused by inaccurate geometric parameters in traditional methods. Secondly, the SolidWorks parametric design technology is used to construct a steel formwork system model, and the optimal formwork configuration scheme is determined through mechanical analysis and verification to ensure that the formwork system has sufficient rigidity and stability, providing reliable physical support conditions for angle control. In terms of measurement technology, the present invention adopts the minimum dominating set algorithm based on graph theory to optimize the monitoring node layout, ensuring that all key geometric features of the bifurcation column are covered with the least number of measurement points. Through a multi-sensor fusion system composed of multi-point laser ranging sensors and high-resolution industrial cameras, high-precision real-time measurement of the bifurcation column angle is achieved, with a measurement accuracy of up to 0.1 degrees. In terms of control algorithms, the present invention establishes a series of mathematical models such as angle deviation correction equations, support stiffness evaluation equations, angle stability evaluation equations, and dynamic adjustment control equations. Based on structural mechanics theory, Euler buckling theory, control system stability theory, and PID control theory, it realizes scientific quantification and precise adjustment of the angle control process. By using the spatiotemporal alignment algorithm and the Kalman filter algorithm to fuse and reduce noise of multi-sensor data, measurement errors and environmental interference are eliminated, ensuring the accuracy and reliability of the angle data. The entire technical solution forms a complete closed-loop control system from design modeling, template production, on-site measurement to dynamic adjustment. It replaces traditional empirical judgment and manual adjustment with digital means, realizing scientific and precise control of the bifurcation column angle.

[0061] A specific embodiment 1 of the present invention is provided below. The specific implementation of each step in this embodiment 1 is described in detail as follows.

[0062] In this embodiment, the specific implementation of steps S01-S03 is the same as above and will not be described in detail here.

[0063] The specific implementation of step S04 is to use the angle deviation correction equation to accurately adjust the installation position of the cantilever section of the bifurcated column. The angle deviation correction equation is based on the elastic deformation theory in structural mechanics and is a correction calculation model established by combining temperature effects and material properties. It is specifically expressed as follows:

[0064]

[0065] Where Δθ is the angle correction value in radians; L cantilever is the cantilever length of the bifurcated column, in m; qself is the deadweight load per unit length of the cantilever section, in N / m; E is the elastic modulus of the steel, in Pa; I is the moment of inertia of the section, in m 4 ; α T is the ambient temperature coefficient, the unit is 1 / ℃; ΔT is the ambient temperature change value, the unit is ℃; θ design is the design bifurcation angle, in radians; P construct is the construction load, unit is N.

[0066] Among them, the parameter acquisition method is: L cantilever Acquired by measuring the three-dimensional model in step S01; self It is calculated by multiplying the concrete density by the cross-sectional area. The calculation formula is q self =ρ concrete ·A section g, where ρ concrete is the concrete density, in kg / m 3 , typical value is 2400kg / m 3 , A section is the cross-sectional area of ​​the cantilever section, in m 2 , g is the acceleration due to gravity, unit is m / s 2 , take 9.8m / s 2 ; E is obtained from the steel material test report, and the typical value is 2.06×10 11 Pa; I is calculated from the cross-sectional geometry; α T The ambient temperature is collected in real time by the on-site temperature sensor and the thermal expansion and contraction coefficient of steel is 1.2×10 -5 / ℃; ΔT is obtained through on-site temperature monitoring; θ design The designed bifurcation angle obtained in step S01; P construct Determined according to the construction process, the typical value is 500N to 2000N.

[0067] The specific implementation of step S05 is to use the support stiffness evaluation equation to verify the bearing capacity of the steel back rib support system. The support stiffness evaluation equation is based on Euler buckling theory and takes into account the constraints and temperature factors. It is specifically expressed as follows:

[0068]

[0069] Where π is the ratio of circumference to circle, and its value is 3.14159. support is the support stiffness value, in N·m; E is the elastic modulus of steel, in Pa; I is the section inertia moment, in m 4 ; k is the length coefficient, dimensionless, ranging from 0.5 to 2.0; L support is the support length, in m; ηboundary is the constraint coefficient, dimensionless; β T is the temperature influence coefficient, the unit is 1 / ℃; ΔT support is the temperature change of the support system, in °C.

[0070] The parameter acquisition method is as follows: the acquisition method of E and I is the same as step S04; k is determined according to the support end constraint condition, k = 0.5 when both ends are fixed, k = 1.0 when both ends are hinged, and k = 0.7 when one end is fixed and the other end is hinged; L support Obtained through on-site measurement; η boundary Determined by the support end connection method, 1.0 for fixed constraint, 0.8 for hinged constraint, and 0.6 to 0.9 for elastic constraint; β T Calculated based on the thermal deformation parameters of steel, the typical value is 5.0×10 -6 / ℃;ΔT support Obtained through on-site temperature monitoring.

[0071] The specific implementation of step S06 is to use the angle stability evaluation equation to evaluate the angle control accuracy of the template system. The angle stability evaluation equation is based on the control system stability theory and establishes a relationship model between angle deviation and time response, which is specifically expressed as follows:

[0072]

[0073] Where |||| represents the absolute value or the second norm. angle is the angular stability factor, dimensionless, ranging from 0 to 1; θ measured is the measured angle data, in radians; θ design is the design reference angle, in radians; R stability is the stability reference value, in radians, with a typical value of 0.01; t measure is the time variable at the measurement moment, in seconds; τ response is the system response time constant, in seconds; ζ is the damping coefficient, dimensionless; is the measured angle change rate, in rad / s.

[0074] Among them, the parameter acquisition method is: θ measured Real-time acquisition through high-definition intelligent monitoring and measurement integrated device; design Derived from the designed bifurcation angle obtained in step S01; t measure Obtained through real-time clock recording during construction; τ response The typical value is 5 to 15s, which is calculated through dynamic analysis of the support system. ζ is determined based on the material damping characteristics and structural damping characteristics of the steel formwork system, with a typical value of 0.05 to 0.15. It is calculated by the time derivative of the angle measurement data, and the calculation formula is: Where dt is the time differential element, the unit is s.

[0075] The specific implementation of step S07 is to use a dynamic adjustment control equation to adjust the support system in real time. The dynamic adjustment control equation is based on the proportional integral differential control theory to establish a control relationship between the angle deviation and the support force adjustment amount, which is specifically expressed as follows:

[0076]

[0077] Integral from 0 to t control Represents the cumulative effect from the start of control to the current moment. Where, F adjust is the support force adjustment, unit is N; K p is the proportional coefficient, the unit is N / rad; e angle is the angular deviation in radians; K i is the integral coefficient, the unit is N / (rad·s); t control To control the integral time, the unit is s; K d is the differential coefficient, the unit is N·s / rad; is the rate of change of angle deviation, in rad / s.

[0078] Among them, the parameter acquisition method is: angle It is calculated by the difference between the measured angle and the designed angle. The calculation formula is e angle =θ measured -θ design ;K p Determined by the linear relationship between the angular deviation and the support force adjustment, the typical value is 1000 to 5000N / rad; K i It is set according to the response characteristics and control accuracy requirements of the angle control system. The typical value is 100 to 500N / (rad·s); K d Determined by the degree of influence of the angle change rate on the support force adjustment, the typical value is 50 to 200 N·s / rad; The angle change rate parameter obtained by the data acquisition device is calculated and the calculation formula is:

[0079] The angle deviation correction equation is based on the theory of elastic mechanics to establish a deformation calculation model for cantilever structures under multiple loads. The equation includes the bending deformation term. Temperature deformation term α T ·ΔT·L cantilever tan(θ design ) and construction load deformation Three main components; bending deformation term Consider the deflection deformation caused by the self-weight of the cantilever section; temperature deformation term α T · ΔT · L cantilever · tan(θ design ) reflects the influence of environmental temperature changes on the geometric size of the structure; construction load deformation term Consider the effect of additional load during construction; compared with the traditional static geometric lofting method, this equation can predict and compensate for the influence of various deformation factors on angle accuracy, significantly improve the accuracy of formwork positioning, and avoid the accumulation of angle deviation caused by deformation.

[0080] The support stiffness evaluation equation establishes a stability determination model for support components based on the Euler buckling theory, which comprehensively considers the influence of material properties, geometric parameters, constraint conditions and environmental factors on support stiffness; Euler buckling term Reflects the difference in buckling length under different constraint conditions; constraint condition coefficient term η boundary Quantifies the influence of boundary constraints on bearing capacity; temperature correction term (1-β T ΔT support ) considers the influence of temperature changes on material properties; compared with the traditional empirical design method, this equation can accurately calculate the bearing capacity and stability of the support system, ensure that the formwork system has sufficient safety reserve under complex load conditions, and avoid construction accidents caused by support instability.

[0081] The angle stability evaluation equation establishes a dynamic evaluation model for angle accuracy based on control system stability theory, which uses an exponential decay function to describe the trend of angle deviation over time, and the damping term reflects the system's suppression ability of angle change rate; exponential decay term Characterizes the convergence characteristics of angle deviation; damping term Embodies the dynamic response characteristics of the system; compared with the traditional static detection method, this equation can evaluate the stability and convergence of the angle control system in real time, predict the development trend of angle accuracy, provide a scientific basis for timely adjustment, and ensure the continuous effectiveness of angle control.

[0082] The dynamic adjustment control equation establishes an automatic adjustment model for support force based on proportional-integral-derivative control theory, which contains three basic components: proportional control term K p ·e angle , integral control term and differential control term ; proportional term K p ·e angle provides a control action proportional to the current angle deviation; integral term Eliminate the steady-state error of the system; the differential term Improve the dynamic response characteristics of the system;

[0083] Compared with the traditional manual adjustment method, the equation realizes the automatic and accurate control of the support force, significantly improves the response speed and control accuracy of the angle control, reduces the human operation error, and ensures the stable maintenance of the angle accuracy in the complex construction environment.

[0084] In order to better understand and implement the present application, the following provides an embodiment 2 of a specific application scenario of the present application: the main structure of a certain airport terminal is a reinforced concrete frame structure, and the departure hall adopts a roof steel truss system supported by multiple hyperbolic variable cross-section concrete bifurcated columns. The design height of the bifurcated column is 12.8m, the bottom section of the main column is a rectangular section with a size of 1200mm×800mm, the bifurcation point is located at a distance of 8.5m from the bottom, the bifurcation angle is 48°, the length of the two cantilever branches is 3.2m, and the section at the connection between the top and the roof beam is 600mm×400mm. The technical team is faced with technical difficulties such as complex bifurcated column modeling, high angle control accuracy requirements, and the difficulty of traditional formwork support system to meet the construction requirements.

[0085] The technical team first uses Rhino curved surface modeling technology to model the hyperbolic variable cross-section concrete bifurcated column in three dimensions. Based on the plane coordinates and elevation data of the design drawing, a NURBS curved surface model is created in Rhino software, and key parameters such as the cantilever length of the bifurcated column of 3.2m, the bending curvature radius of 15.6m, and the design bifurcation angle of 48° are accurately obtained. The complete three-dimensional positioning model of the bifurcated column is constructed through the curved surface modeling technology, and the cantilever length and the design bifurcation angle are output as the three-dimensional lofting reference on site. During the modeling process, the center point of the bottom of the main column is set as the coordinate origin (0, 0, 0), the bifurcation point coordinates are (0, 0, 8500), and the top coordinates of the two cantilever branches are (2392, 1856, 12800) and (-2392, 1856, 12800) respectively.

[0086] Based on the three-dimensional positioning model of the bifurcated column, the technical team uses SolidWorks parametric design technology to construct the steel formwork system model. The steel material is Q235B steel, the elastic modulus is 206000MPa, and the formwork thickness is 5mm. The rectangular section moment of inertia is determined through material mechanics calculation, the moment of inertia of the bottom section of the main column I x = 5.12 × 10 8 mm 4 , I y = 2.05 × 10 8 mm 4The support length is set according to the site conditions, the vertical rod spacing is 600 mm, and the horizontal rod step is 1500 mm. When modular design is performed, the entire steel formwork system is divided into 26 standard modules including a bottom formwork module, a side formwork module and a top formwork module, wherein the standard modules that can be recycled account for 73% of the total number. Digital processing drawings are generated through parametric design technology to ensure the dimensional accuracy and assembly fit of the modules.

[0087] During the site construction phase, the technical team uses the Leica TS16 total station to perform high-precision three-dimensional lofting. The angle measurement accuracy of the total station is 0.5", and the distance measurement accuracy is 1 mm + 1.5 ppm. The center points of the bottom of the bifurcated column main column and the planar projection points of the cantilever section are set as planar control points, and the planar coordinate accuracy of the control points is controlled within ± 2 mm. The elevation of the connection between the bifurcated top and the beam slab is set as a vertical control point, and the elevation control accuracy is ± 3 mm. The obtained formwork positioning coordinate data is shown in Table 1.

[0088] Table 1: Coordinate data table of key control points of bifurcated column

[0089] Control point location X coordinate (mm) Y coordinate (mm) Z coordinate (mm) Measurement accuracy (mm) Center of the bottom of the main column 0 0 0 ±1.5 Bifurcation Center 0 0 8500 ±2.0 Left cantilever end 2392 1856 12800 ±2.5 Right cantilever end -2392 1856 12800 ±2.5 Left projection point 2392 1856 0 ±1.5 Right projection point -2392 1856 0 ±1.5

[0090] When installing the bottom formwork of the bifurcated column cantilever section, the technical team uses φ48 disc buckle vertical rod to support the formwork bottom channel steel, and the vertical rod is made of Q345 steel with a wall thickness of 3.2 mm. Adjustable pull rods made of φ38 threaded steel pipes are used for temporary positioning and support, with an adjustment range of ± 50 mm. According to the site environment temperature of 26℃, the environmental temperature coefficient is calculated to be 1.00012 by real-time data acquisition through a temperature sensor. By inputting the cantilever length of the bifurcated column 3.2 m, the design bifurcation angle 48°, the environmental temperature coefficient 1.00012, the material elastic modulus 206000 MPa, and the cross-sectional moment of inertia 5.12 x 10 8 mm 4 , the angle correction value is calculated to be -0.08°, and the formwork positioning parameters are adjusted accordingly. The cantilever section bottom formwork is installed in a modular manner, ensuring installation accuracy and construction efficiency.

[0091] During the installation of the bifurcated column main column side formwork, the technical team uses steel grating with a height of 8 cm as a steel back rib reinforcement system. The steel grating is made of Q235 steel with a horizontal spacing of 300 mm and a longitudinal reinforcement spacing of 1000 mm. Temporary pull rod supports are provided at each cross section, and double pull rods are provided between the two cantilever bifurcated columns. By inputting the steel elastic modulus 206000 MPa, the cross-sectional moment of inertia 5.12 x 10 8 mm 4 , the support length 1000 mm, the constraint condition coefficient 0.85, and the temperature influence coefficient 1.00012 into the support stiffness evaluation equation, the support stiffness value is calculated to be 1.75 x 10 6N·m, which meets the stability requirements of the support system. The installation process is shown in Figure 2

[0092] The technical team used three-dimensional positioning verification technology to conduct comprehensive detection on the installed steel formwork system. A self-developed high-definition intelligent monitoring and measurement integrated device was used, which integrated 16 laser ranging sensors and 4 high-resolution industrial cameras. First, a node graph network was constructed based on the three-dimensional positioning model of the bifurcated column, with 42 geometric feature points as graph nodes and structural connection relationships as graph edges. The minimum dominating set algorithm was used to select 12 key monitoring nodes from the node graph network, ensuring that all key geometric features of the bifurcated column were covered with the least number of nodes. Multi-point laser ranging sensors were placed at the key monitoring node positions, with a measurement accuracy of 0.05 mm. Three-dimensional coordinate measurement was used to obtain the measured angle data. The high-resolution industrial camera had a resolution of 2048x1536 pixels, and a sub-pixel level image processing algorithm was used to identify the position changes of the bifurcated column edge feature points. A spatio-temporal alignment algorithm was used to fuse the multi-sensor data, eliminating the 5 ms measurement time difference and spatial coordinate system deviation. A Kalman filter algorithm was used for noise reduction processing of the measurement data, removing environmental vibration and equipment noise interference, and ensuring that the angle measurement accuracy was controlled within 0.08°. The detected angle data is shown in Table 2.

[0093] Table 2 Bifurcated Column Angle Detection Data

[0094]

[0095] By inputting the angle deviation amount ±0.08°, the design reference angle 48°, the time variable 360 min, the damping coefficient 0.08, and the system response time constant 15 s into the angle stability evaluation equation, the angle stability factor was calculated to be 0.92, and the angle control accuracy was determined to meet the design requirements.

[0096] During the concrete pouring process, the technical team continuously monitored the formwork system deformation and displacement. C40 concrete was used, with a design strength of 40 MPa and a slump control of 180±20 mm. The pouring process was divided into three layers, with each layer being about 4.3 m high, and the pouring speed was controlled at 2.5 m 3 / h. The angle change rate was obtained through the data acquisition device, and the monitoring data showed that the maximum angle change rate was 0.02° / h. By inputting the angle deviation amount ±0.08°, the angle change rate 0.02° / h, the integral time constant 120 s, the proportional coefficient 1.5, and the differential coefficient 0.3 into the dynamic adjustment control equation, the support force adjustment amount was calculated to be 850 N, and the support system was adjusted in time to ensure the angle accuracy. The pouring process monitoring data is shown in Table 3.

[0097] Table 3 Concrete Pouring Process Monitoring Data ​

[0098]

[0099] After the concrete pouring was completed, the bifurcated columns had good forming effects, with a flat and smooth surface, meeting the standard requirements of fair-faced concrete.

[0100] 48 hours after the concrete pour, when the concrete strength reached 75% of the design strength, the technical team began dismantling the side and cover forms. The dismantling process was carried out in a strict top-down order, starting with the quick-release clips, then using a wrench to remove the connecting bolts. Then, using a crowbar, they gently pried the cantilevered bottom formwork from the underside. When removing the cantilevered bottom formwork, a quick-release steel formwork system was utilized, retaining the cantilevered support system to share the vertical load. The support system was removed only after the concrete strength reached 100%.

[0101] The final construction results showed that the angle control accuracy of the 42 hyperbolic variable-section concrete bifurcated columns was within ±0.08°, and the surface quality met the standards for bare concrete, with no defects such as tie screw holes. The steel formwork turnover rate reached 73%, effectively reducing material costs. The construction period was shortened by 12% compared to traditional methods, significantly improving quality control.

[0102] Compared to the traditional steel pipe and tie screw formwork support system, this technical solution has achieved significant improvements in angle control accuracy, construction quality, and efficiency. The angle control accuracy of traditional methods is usually around ±0.15°, while this technical solution improves the accuracy to ±0.08°, an increase of approximately 47%. The traditional method has the problem of slurry leakage in the tie screw holes, which requires later repair. This technical solution completely avoids this problem by adopting a non-perforated reinforcement system. The formwork turnover rate of traditional methods is usually 50% to 60%. This technical solution increases the turnover rate to 73% through modular and standardized design, and improves material utilization by approximately 15%. Traditional methods are prone to quality problems such as deformation and misalignment in the construction of complex and special-shaped structures. This technical solution effectively solves these problems through precise three-dimensional modeling, parametric design, and intelligent monitoring technology. The concrete forming quality meets the standard of plain concrete, and the surface flatness is controlled within 2mm. Traditional methods require a lot of manual adjustments and repeated corrections, resulting in low construction efficiency. This technical solution significantly improves construction efficiency through visualization technology and standardized operating procedures. The construction period of a single bifurcated column is shortened from the traditional 7 days to 6 days, an efficiency improvement of approximately 14%.

[0103] It should be noted that the variables involved in the present invention are explained in detail as shown in Table 4 below.

[0104] Table 4 Variable explanation table

[0105]

[0106] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed by the present invention, which should be covered by the scope of protection of the present invention.

Claims

1. A method for accurately controlling the angle of a bifurcated column, characterized in that: 3D modeling of the hyperbolic variable-section concrete bifurcated column was performed to obtain the bifurcated column cantilever length, arc curvature, and designed bifurcation angle, and a 3D positioning model of the bifurcated column was constructed. A steel formwork system model was constructed based on the 3D positioning model of the bifurcated column to obtain the steel elastic modulus, section moment of inertia, and support length, and to determine the standard formwork module configuration scheme. A total station was used for high-precision 3D lofting to obtain the formwork positioning coordinates for preliminary positioning. When installing the cantilever bottom formwork of the bifurcated column, adjustable tie rods were used for temporary positioning and support. The angle correction value was calculated using the angle deviation correction equation and the positioning parameters were adjusted. During the installation of the side formwork of the bifurcated column main column, a steel back rib reinforcement system was used, and the support stiffness value was calculated using the support stiffness evaluation equation to determine the stability of the support system. The steel formwork system is inspected using three-dimensional positioning and calibration technology. The measured angle data and angle deviation are obtained through an intelligent monitoring and measurement integrated device. An angle stability evaluation equation is established to calculate the angle stability factor and determine the angle control accuracy. During the concrete pouring process, the deformation and displacement of the formwork system are monitored, the angle change rate is obtained through the data acquisition device, the dynamic adjustment control equation is used to calculate the support force adjustment amount and adjust the support system to ensure angle accuracy.

2. The method for accurately controlling the angle of a bifurcated column according to claim 1, characterized in that: A hyperbolic variable-section concrete bifurcated column specifically refers to a concrete column with a hyperbolic shape and a cross-section that changes along the height direction, forming two or more cantilevered branch structures at the bifurcation position.

3. The method for accurately controlling the angle of a bifurcated column according to claim 2, characterized in that: The steps of constructing the three-dimensional positioning model of the bifurcation column are to output the cantilever length of the bifurcation column and the designed bifurcation angle as the on-site three-dimensional layout benchmark, and the steps of constructing the steel formwork system model are to perform modular design and verification and generate digital processing drawings.

4. The method for accurately controlling the angle of a bifurcated column according to claim 3, characterized in that: The steps for using a total station for high-precision three-dimensional layout are to set the bottom of the main column of the bifurcated column and the plane projection point of the cantilever section as the plane control points, and the elevation of the bifurcated top and the connection between the beam and slab as the vertical control point for preliminary positioning.

5. The method for accurately controlling the angle of a bifurcated column according to claim 4, characterized in that: The steps for installing the bottom formwork of the cantilever section of the bifurcated column are to use vertical poles to support the bottom channel steel of the formwork, and input the bifurcated column cantilever length, designed bifurcation angle, ambient temperature coefficient, material elastic modulus, and section moment of inertia into the angle deviation correction equation.

6. The method for accurately controlling the angle of a bifurcated column according to claim 5, characterized in that: The steps for using the steel back rib reinforcement system are as follows: the reinforcement spacing is set to 1000mm, temporary tie rod support is set at each section, double tie rods are set between the two cantilevered bifurcated columns, and the support stiffness evaluation equation inputs the steel elastic modulus, section inertia moment, support length, constraint coefficient, and temperature influence coefficient.

7. The method for accurately controlling the angle of a bifurcated column according to claim 6, characterized in that: The steps of using three-dimensional positioning and verification technology for detection are to conduct a full-scale inspection of the installed steel formwork system. The angle stability evaluation equation inputs the angle deviation, design reference angle, time variable, damping coefficient, and system response time constant.

8. The method for accurately controlling the angle of a bifurcated column according to claim 7, characterized in that: The monitoring steps during the concrete pouring process are to continuously monitor the deformation and displacement of the formwork system, and dynamically adjust the control equation input angle deviation, angle change rate, integral time constant, proportional coefficient, and differential coefficient.

9. The method for accurately controlling the angle of a bifurcated column according to claim 8, characterized in that: The intelligent monitoring and measurement integrated device is specifically a monitoring device that integrates measurement sensors and image recognition technology, which is used to collect bifurcation column geometric parameters and deformation data in real time.

10. The method for accurately controlling the angle of a bifurcated column according to claim 9, characterized in that: The method for determining key monitoring nodes is to construct a node graph network based on the three-dimensional positioning model of the bifurcation column, use the geometric feature points of the bifurcation column as graph nodes, and the structural connection relationship as graph edges. The minimum dominating set algorithm is used to select key monitoring nodes from the node graph network to ensure that all key geometric features of the bifurcation column are covered with the minimum number of nodes.

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