Overhead hoisting method for cantilever section steel structure

Abstract

The invention relates to an overhead hoisting method for a cantilever section steel structure, which comprises the following steps: S1, presetting a reversible deformation compensation value in a component processing stage of a cantilever section to form the cantilever section steel structure with a pre-camber curve; s2, a multi-stage positioning device is installed at the root of the cantilever; s3, adjusting the aerial posture of the cantilever section steel structure by adopting a hoisting system; s4, setting an environmental parameter compensation module; s5, after the cantilever section is in place, a distributed jacking device is activated; s6, monitoring welding stress distribution through a fiber grating sensor embedded in the cantilever section, and implementing multi-level welding fixation by adopting a gradient cooling method; and S7, after installation and fixation of the cantilever section steel structure are completed, the load of the distributed jacking and supporting device is released in stages. According to the overhead hoisting method for the cantilever section steel structure, the hoisting positioning precision is high, the construction period is short, the using amount of temporary supports is small, the problems that the overhead hoisting stability is poor, and the precision is difficult to control are solved, and the construction requirements of the steel structure in the complex environment are met.

Description

Technical Field

[0001] The present application relates to the technical field of building construction, and specifically to a method for aerial hoisting of a cantilevered steel structure. Background Art

[0002] In recent years, with the growing demand for large-span buildings and complex spatial structures, the application of cantilevered steel structures has become increasingly widespread. Due to their large cantilever lengths and complex load-bearing conditions, these structures face technical challenges during construction, including poor hoisting stability, high positioning accuracy requirements, and high costs for temporary support components. Traditional construction methods often rely on full-height support frames erected on the ground or on segmented hoisting followed by high-altitude welding. However, due to site conditions and structural characteristics, this approach prolongs construction cycles and increases safety risks, a particularly significant issue in densely populated urban areas or high-altitude operations.

[0003] In related technologies, there are two main methods for hoisting cantilever steel structures: one is to erect temporary support towers to assist in positioning. This method requires a large amount of steel and manpower, and the support structure is difficult to dismantle, making it uneconomical. The other is to hoist the sections in sections and then complete the splicing through high-altitude adjustments. However, due to wind loads, temperature deformation, and human measurement errors, cumulative deviations are prone to occur, resulting in misalignment of connection nodes and even structural stress concentration. In addition, related technologies often rely on manual experience to adjust positioning, lack real-time dynamic monitoring and feedback mechanisms, and are difficult to adapt to the high-precision control requirements in complex environments. The cantilever ends are prone to positioning offsets due to excessive deflection. Summary of the Invention

[0004] In an embodiment of the present application, a method for aerial hoisting of a cantilevered steel structure is provided to solve the problem of how to improve the hoisting control accuracy and reduce the probability of positioning deviation at the cantilevered end.

[0005] The present application provides a method for aerial hoisting of a cantilevered steel structure, comprising the following steps:

[0006] Step S1: presetting an anti-deformation compensation value during the component processing stage of the cantilever section to form a cantilever section steel structure with a pre-camber curve, wherein the cantilever section steel structure has a cantilever root and a cantilever end;

[0007] Step S2, installing a positioning device at the cantilever root, wherein the positioning device includes a fixture, a rotating table, and a laser tracking target, and establishing a dynamic coordinate system with the cantilever end as a reference point;

[0008] Step S3: Using a hoisting system to adjust the aerial posture of the cantilevered steel structure, and using an inertial navigation module attached to a sling of the hoisting system to provide real-time feedback on the spatial coordinates of the cantilevered steel structure, and performing a dynamic deviation comparison with the design model in combination with the scanned coordinate data of the laser tracking target;

[0009] Step S4, setting an environmental parameter compensation module and synchronously collecting wind speed data and temperature gradient data, wherein the environmental parameter compensation module controls the rotating stage to perform millimeter-level closed-loop correction of the rotation angle according to the wind speed data and the temperature gradient data;

[0010] Step S5: activating a distributed jacking device after the cantilever section is in place, the distributed jacking device comprising a plurality of correspondingly arranged pressure self-sensing hydraulic cylinders and detachable articulated supports, each of the pressure self-sensing hydraulic cylinders being connected to the cantilever section via the corresponding detachable articulated support to form a segmented temporary support assembly, wherein the spacing between the support points of the cantilever section supported by adjacent pressure self-sensing hydraulic cylinders ranges from 0.25 times to 0.35 times the cantilever length and is nonlinearly distributed;

[0011] Step S6, monitoring welding stress distribution by using a fiber grating sensor embedded in the cantilevered section, and implementing multi-level welding fixation using a gradient cooling method;

[0012] Step S7, after completing the installation and fixation of the cantilever section steel structure, release the load of the distributed supporting device in stages, and simultaneously monitor the deformation of the cantilever section steel structure until it reaches the designed stress state, and then remove the segmented temporary support assembly.

[0013] In one embodiment, the step of forming the cantilevered steel structure with a pre-camber curve includes:

[0014] Finite element simulation was performed based on 1.2 to 1.5 times the design load of the cantilever section, and the maximum deformations δx, δy, and δz along the X, Y, and Z axes were extracted;

[0015] Generate a spatial compensation curve according to the proportional relationship of (0.8~0.9)δx, (1.0~1.1)δy, and (1.2~1.3)δz;

[0016] Presetting the anti-deformation compensation value according to the space compensation curve during the component processing stage of the cantilever section;

[0017] According to the anti-deformation compensation value, the cantilever section steel structure is provided with a pre-supplied curve.

[0018] In one embodiment, in step S2, the rotation stage has three translational degrees of freedom in X, Y, and Z axes and a rotational degree of freedom around the Z axis.

[0019] In one embodiment, in step S3, the hoisting system is a dual-machine collaborative hoisting system, and the dual-machine collaborative hoisting system includes a master crane and a slave crane. The dual-machine collaborative hoisting system adopts a master-slave control mode, wherein the master crane bears the main load, and the slave crane uses a tension sensor to provide real-time feedback on the tension value of the sling.

[0020] In one embodiment, in step S4, the environmental parameter compensation module controls the rotating stage to perform millimeter-level closed-loop correction according to the wind speed data and the temperature gradient data, including:

[0021] A neural network algorithm is used to establish an environmental parameter-deformation mapping model, wherein the environmental parameters include the wind speed data and the temperature gradient data;

[0022] Using the environmental parameter-deformation mapping model, finite element reverse calculation is performed to generate dynamic compensation instructions;

[0023] The control system controls the rotating stage to perform millimeter-level closed-loop correction of the rotation angle according to the dynamic compensation instruction.

[0024] In one embodiment, in step S5, the distribution rule of the distance L between the support points satisfies:

[0025]

[0026] Wherein, Li is the reinforcement spacing at point i, K=(0.28~0.32)L, L is the total length of the cantilever section, Mi is the design bending moment value at point i, and Mmax is the maximum bending moment value of the cantilever section corresponding to the cantilever root.

[0027] In one embodiment, in step S6, the gradient cooling method includes: first cooling to a preset temperature range at a preset rate and keeping the temperature for a preset time, and then cooling to ambient temperature at another slower preset rate.

[0028] In one embodiment, in step S7, when releasing the load of the distributed supporting device in stages, the unloading sequence is implemented in multiple stages, and the load released in each stage does not exceed 1 / 3 of the total load.

[0029] In one embodiment, before step S1, the method further includes the following steps: arranging a distributed thin film pressure sensor on the surface of the cantilevered section, wherein the distributed thin film pressure sensor includes a film material, a resistance strain gauge array, and a temperature compensation unit, wherein the resistance strain gauge array and the temperature compensation unit are both arranged on the film material;

[0030] The distribution density of distributed thin film pressure sensors meets the following requirements:

[0031]

[0032] Among them, N sensor is the total number of effective sensing units in the resistance strain gauge array, A is the monitoring area, and ζ is the minimum density threshold.

[0033] In one embodiment, the maximum compensation amount of the pre-camber curve is:

[0034]

[0035] The curvature radius variation gradient of the cantilevered steel structure corresponding to the cantilevered end section satisfies:

[0036]

[0037] Wherein, ξ is a dimensionless coefficient related to the cross-sectional shape coefficient and load distribution of the cantilever section, L is the total length of the cantilever section, ΔR is the change in curvature radius, Δs is the arc length increment, and R0 is the initial curvature radius.

[0038] The above-mentioned aerial hoisting method of the cantilever section steel structure realizes the precise positioning, safe hoisting and stable installation of the cantilever section steel structure during the aerial hoisting process through technical means such as preset anti-deformation compensation value, dynamic positioning, environmental parameter compensation, segmented temporary support and gradient cooling welding, reduces the probability of positioning deviation at the cantilever end, and ensures construction quality and structural safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, without paying any creative work, they can also obtain drawings of other embodiments based on these drawings.

[0040] Figure 1 This is a flow chart of the steps of a method for aerial hoisting of a cantilevered steel structure according to one embodiment of the present application.

[0041] Figure 2 This is a schematic structural diagram of the clamps used in the aerial hoisting method of the cantilevered section steel structure according to one embodiment of the present application.

[0042] Figure 3 This is a structural schematic diagram of a distributed jacking device used in the aerial hoisting method of a cantilevered section steel structure in one embodiment of the present application.

[0043] Description of reference numerals:

[0044] 20. Positioning device; 21. Fixture; 22. Rotating table; 23. Laser tracking target; 30. Distributed supporting device; 31. Pressure self-sensing hydraulic cylinder; 32. Removable articulated support. DETAILED DESCRIPTION

[0045] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0046] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element.

[0047] The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions are for illustrative purposes only and do not represent the only implementations.

[0048] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0049] In the embodiments of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0050] See Figure 1 As shown, one embodiment of the present application provides an aerial hoisting method for a cantilevered steel structure, which can be adapted to hoisting operations of a cantilevered steel structure.

[0051] Combine Figures 1 to 3 As shown, the aerial hoisting method of the cantilevered steel structure includes the following steps:

[0052] Step S1: presetting an anti-deformation compensation value during the component processing stage of the cantilever section to form a cantilever section steel structure with a pre-camber curve, wherein the cantilever section steel structure has a cantilever root and a cantilever end.

[0053] In step S1, by presetting the anti-deformation compensation value, a cantilevered steel structure with a pre-camber curve is formed. This can offset future deformation caused by loads to a certain extent, thereby improving the overall stability and load-bearing capacity of the structure. Furthermore, because future deformation is taken into account and compensated for in advance during the component processing stage, adjustment work is reduced during the hoisting and construction phases, improving construction accuracy and efficiency.

[0054] In step S2, a positioning device 20 is installed at the cantilever root. The positioning device 20 includes a fixture 21, a rotating platform 22, and a laser tracking target 23 to establish a dynamic coordinate system with the cantilever end as a reference point.

[0055] In this step S2, by installing a positioning device 20 at the root of the cantilever, the position and posture of the cantilever section steel structure can be accurately determined. In addition, the laser tracking target 23 is used to provide high-precision coordinate data to ensure the position accuracy of the cantilever section steel structure during the installation process. Among them, the design of the clamp 21 and the rotating table 22 allows the positioning device 20 to be adjusted in multiple directions to adapt to installation requirements of different angles and directions. In this way, establishing a dynamic coordinate system with the cantilever end as the reference point can make positioning and adjustment during the construction process more flexible and convenient. Understandably, high-precision positioning can reduce rework and delays caused by inaccurate positioning, thereby improving overall construction efficiency.

[0056] In step S3, the aerial posture of the cantilevered steel structure is adjusted using the hoisting system, and the spatial coordinates of the cantilevered steel structure are fed back in real time through the inertial navigation module attached to the sling of the hoisting system. The scanning coordinate data of the laser tracking target 23 is combined with the design model for dynamic deviation comparison.

[0057] In step S3, the inertial navigation module and the laser tracking target 23 together form a composite measurement network to eliminate the hoisting swing error, and drive the hoisting system to automatically adjust the sling tension and angle through dynamic deviation comparison to achieve closed-loop deviation correction, so as to improve the positioning accuracy of the cantilever end.

[0058] Step S4, setting an environmental parameter compensation module and synchronously collecting wind speed data and temperature gradient data. The environmental parameter compensation module controls the rotating platform 22 to perform millimeter-level closed-loop correction of the rotation angle according to the wind speed data and temperature gradient data.

[0059] In step S4, the environmental parameter supplementation module uses wind speed and temperature gradient data to perform millimeter-level closed-loop corrections on the rotating stage 22 to suppress the end swing amplitude caused by wind loads. The temperature gradient data is also used to predict the thermal deformation trend of the steel structure and compensate for linear expansion deviations in advance. This, in turn, facilitates the control accuracy of the cantilever steel structure during aerial hoisting.

[0060] Step S5: After the cantilever section is in place, the distributed jacking device 30 is activated. The distributed jacking device 30 includes multiple groups of correspondingly set pressure self-sensing hydraulic cylinders 31 and detachable articulated supports 32. Each pressure self-sensing hydraulic cylinder 31 is connected to the cantilever section through the corresponding detachable articulated support 32 to form a segmented temporary support assembly. The spacing between the support points of the cantilever section supported by adjacent pressure self-sensing hydraulic cylinders 31 ranges from 0.25 times to 0.35 times the cantilever length, and is nonlinearly distributed.

[0061] In step S5, multiple groups of pressure-sensing hydraulic cylinders 31 form a distributed load-bearing network. This allows adjacent groups to automatically compensate for any failures, preventing localized instability. Furthermore, support points are distributed at a nonlinear spacing of 0.25 to 0.35 times the cantilever length to reduce bending moments at the cantilever root, thereby reducing stress and ensuring the stability of the cantilever steel structure.

[0062] Step S6: monitoring the welding stress distribution by using a fiber optic Bragg grating sensor embedded in the cantilevered section, and implementing multi-level welding fixation by using a gradient cooling method.

[0063] In step S6, the welding stress distribution is monitored by fiber Bragg grating sensors to identify stress concentration areas in real time, so that the welding sequence can be adjusted in advance to suppress crack initiation. The gradient cooling method makes the temperature field distribution more uniform, thereby reducing the deflection deformation of the cantilever section after welding.

[0064] Step S7, after completing the installation and fixation of the cantilever section steel structure, release the load of the distributed supporting device 30 in stages, and simultaneously monitor the deformation of the cantilever section steel structure until it reaches the designed stress state, and then remove the segmented temporary support assembly.

[0065] The aerial hoisting method of the cantilever section steel structure in the embodiment of the present application realizes the precise positioning, safe hoisting and stable installation of the cantilever section steel structure during the aerial hoisting process through technical means such as preset anti-deformation compensation value, dynamic positioning, environmental parameter compensation, segmented temporary support and gradient cooling welding, reduces the probability of positioning deviation at the cantilever end, and ensures construction quality and structural safety.

[0066] In some embodiments, before presetting the anti-deformation compensation value, the three-dimensional deformation of the cantilever section can be analyzed based on the BIM model. In this way, the preset anti-deformation compensation value can be accurately set according to the three-dimensional deformation of the cantilever section.

[0067] In some embodiments, the step of forming a cantilevered steel structure with a pre-camber curve includes:

[0068] Finite element simulation was performed based on 1.2 to 1.5 times the design load of the cantilever section, and the maximum deformations δx, δy, and δz along the X, Y, and Z axes were extracted.

[0069] Generate a spatial compensation curve according to the proportional relationship of (0.8~0.9)δx, (1.0~1.1)δy, and (1.2~1.3)δz.

[0070] During the component processing stage of the cantilever section, the anti-deformation compensation value is preset according to the space compensation curve.

[0071] According to the anti-deformation compensation value, the cantilever section steel structure has a pre-supplied curve.

[0072] In this implementation, finite element analysis is performed using 1.2 to 1.5 times the design load to proactively identify the extreme three-dimensional deformation values ​​(δx, δy, and δz) of the cantilever section under extreme loads, ensuring structural safety. A spatial compensation curve is generated based on the proportional relationship between (0.8 to 0.9) δx, (1.0 to 1.1) δy, and (1.2 to 1.3) δz to specifically offset non-uniform deformation after installation. Through finite element simulation and anti-deformation pre-compensation control, the construction accuracy and safety of the cantilever section steel structure can be significantly improved.

[0073] In some embodiments, in step S2, the rotating stage 22 has three degrees of freedom (X, Y, and Z) for translation, as well as a degree of freedom for rotation about the Z axis. This allows the positioning device 20 to be adjusted in multiple directions, adapting to installation requirements at various angles and orientations. It should be noted that the single-axis adjustment accuracy meets the preset positioning requirements, and the positioning error of the laser tracking target 23 is controlled within a preset range.

[0074] In some embodiments, in step S3, the hoisting system is a dual-machine collaborative hoisting system, comprising a master crane and a slave crane. The dual-machine collaborative hoisting system employs a master-slave control mode, wherein the master crane bears the primary load, while the slave crane uses a tension sensor to provide real-time feedback on the sling tension value, thereby dynamically adjusting the output ratio. It should be noted that the dual-machine collaborative hoisting system reduces the risk of overload and overturning caused by uneven force in traditional hoisting techniques.

[0075] In some embodiments, in step S4, the environmental parameter compensation module controls the rotating stage 22 to perform millimeter-level closed-loop correction based on the wind speed data and the temperature gradient data, including:

[0076] A neural network algorithm is used to establish an environmental parameter-deformation mapping model, where the environmental parameters include wind speed data and temperature gradient data.

[0077] The environmental parameter-deformation mapping model is used to perform finite element inverse calculation to generate dynamic compensation instructions.

[0078] The control system controls the rotating platform 22 to perform millimeter-level closed-loop correction of the rotation angle according to the dynamic compensation instruction.

[0079] It's important to note that the frequency of wind speed data collection and the measurement interval of temperature gradient data both meet the requirements of dynamic compensation calculations. For example, an environmental parameter-deformation mapping model built using an LSTM neural network converts mechanical deformation caused by wind speed fluctuations (e.g., 0-13 m / s) and temperature gradients (e.g., -50°C to +85°C) into compensation commands, reducing positioning error to ±0.02 mm. The temperature gradient data measurement interval is ≤10 cm, and combined with dynamic compensation with a 50 ms response speed, it eliminates axial deviation caused by thermal deformation (e.g., compensation residual ≤0.005 mm for an 80°C temperature difference).

[0080] Since the control system controls the rotating table 22 to perform millimeter-level closed-loop correction of the rotation angle according to the dynamic compensation instruction, and the dynamic compensation instruction is generated by finite element inverse calculation through the environmental parameter-deformation mapping model, therefore, when the environmental parameters in the environmental parameter-deformation mapping model include wind speed data and temperature gradient data, after the rotating table 22 performs millimeter-level closed-loop correction of the rotation angle, it can suppress the terminal swing amplitude caused by wind load and compensate for linear expansion deviation, which is beneficial to controlling the control accuracy of the cantilever section steel structure in the air hoisting.

[0081] In some embodiments, in step S5, the distribution rule of the distance L between the support points satisfies:

[0082]

[0083] Where Li is the reinforcement spacing at point i, K=(0.28~0.32)L, L is the total length of the cantilever section, Mi is the design bending moment value at point i, and Mmax is the maximum bending moment value of the cantilever section corresponding to the cantilever root.

[0084] In this embodiment, the support point spacing Li is dynamically adjusted according to the moment distribution ratio ‌Mi / Mmax, and the reinforcement is increased at the cantilever root (Mmax ​​area) (Li is minimum) and the spacing is gradually relaxed toward the cantilever end (moment attenuation area) to achieve dynamic matching of the moment distribution and avoid the waste of traditional equidistant reinforcement. Compared with the equidistant reinforcement scheme, the dynamic matching of the moment of the support points in this embodiment can reduce the amount of steel bars in the cantilever section steel structure to reduce costs, thereby achieving coordinated optimization of the safety and economy of the cantilever section steel structure.

[0085] In some embodiments, in step S6, the gradient cooling method includes first cooling the temperature at a preset rate to a preset temperature range and holding the temperature for a preset time, followed by cooling the temperature to ambient temperature at a slower preset rate. This staged temperature control (for example, first cooling the temperature at 15°C / min to 250°C and holding the temperature for 10 minutes, followed by cooling the temperature at 5°C / min to ambient temperature) can prevent thermal stress cracking within the cantilever steel structure caused by rapid cooling, thereby improving the fracture toughness of the cantilever steel structure.

[0086] There is no specific limitation on the preset rate, preset temperature range, and preset duration. In the actual construction process, they can be configured according to actual needs. For example, in some embodiments, the gradient cooling method includes: first cooling at a rate of 10°C / min to 30°C / min to a temperature range of 200°C to 300°C and keeping it warm for 5min to 15min, and then cooling to ambient temperature at a rate of 3°C / min to 7°C / min.

[0087] In some embodiments, in step S7, the distributed support device 30 is released in stages, with the unloading sequence being multiple phases, and the load released in each phase not exceeding one-third of the total load. In this embodiment, the phased release can avoid sudden load changes, thereby preventing domino-like collapse caused by support system failure. Furthermore, by ensuring that the load released in each phase is ≤ one-third of the total load, the residual stress transfer rate can be reduced by more than 50%, thereby reducing the risk of brittle failure.

[0088] In some embodiments, before step S1, the method for aerial hoisting of a cantilevered steel structure further comprises the steps of: arranging a distributed thin film pressure sensor on the surface of the cantilevered section, the distributed thin film pressure sensor comprising a membrane material, a resistance strain gauge array, and a temperature compensation unit, wherein the resistance strain gauge array and the temperature compensation unit are both arranged on the membrane material;

[0089] The distribution density of distributed thin film pressure sensors meets the following requirements:

[0090]

[0091] Among them, N sensor is the total number of effective sensing units in the resistance strain gauge array, A is the monitoring area, and ζ is the minimum density threshold.

[0092] In some embodiments, the maximum compensation amount of the pre-camber curve is:

[0093]

[0094] The curvature radius of the cantilever steel structure in the corresponding cantilever end section shall satisfy the following gradient:

[0095]

[0096] where ξ is a dimensionless coefficient related to the cross-sectional shape factor and load distribution of the cantilever, L is the total length of the cantilever, ΔR is the change in the curvature radius, Δs is the arc length increment, and R0 is the initial curvature radius.

[0097] In this embodiment, the distributed thin film pressure sensor and the coordinated control of the pre-camber curve are used to achieve accurate monitoring and deformation compensation of the cantilever section steel structure hoisting process.

[0098] For ease of understanding, the application of the above-mentioned lifting method is explained below by taking a cantilevered steel structure canopy as an example, but it does not mean that the cantilevered steel structure aerial lifting method of the present application is limited to this.

[0099] For example, the total length of the cantilever section of the awning is L=20m, and the design load is 15kN / m².

[0100] The hoisting of the cantilever section of the awning can include the following steps:

[0101] Arrangement of distributed thin film pressure sensors:

[0102] A distributed thin film pressure sensor is pasted on the surface of the component of the cantilever steel cantilever section. The distributed thin film pressure sensor includes a membrane material, a resistance strain gauge array and a temperature compensation unit. The resistance strain gauge array and the temperature compensation unit are both arranged on the membrane material.

[0103] Distributed thin-film pressure sensors cover the entire surface of the steel cantilever. They are flexible sensors capable of continuously measuring surface pressure distribution. Unlike traditional single-point pressure sensors, their key feature is their ability to simultaneously sense the magnitude and location of pressure at multiple locations on a two-dimensional or curved surface.

[0104] In some embodiments, the total number of effective sensing units N in the resistance strain gauge array is sensor = 2000, the monitoring area A = 20 m², and the minimum density threshold ζ = 100 points / m² for deformation sensing of the cantilever segment. Therefore, in this implementation, the data sampling density σ = 2000 / 20 = 100 points / m², satisfying σ ≥ ζ (the minimum density threshold ζ = 100 points / m²). Thus, the resistance strain gauge array can meet the resolution requirement for sensing the surface pressure distribution of the cantilever segment.

[0105] In the above embodiment, the resistance strain gauge array and the temperature compensation unit in the distributed thin film pressure sensor are used to collect stress and temperature data of the components of the cantilever steel section in real time to form a construction period monitoring network.

[0106] Pre-camber curve design:

[0107] A three-dimensional finite element model of the cantilever section was established based on the BIM model. A deformation simulation was performed by applying a load 1.3 times the design load (19.5 kN / m²). The maximum deformations along the X, Y, and Z axes were extracted as δx=15 mm (horizontal), δy=25 mm (vertical), and δz=10 mm (longitudinal), respectively.

[0108] The spatial compensation curve is generated according to the proportions of 0.8δx (12mm), 1.0δy (25mm), and 1.2δz (12mm). The maximum compensation amount of pre-camber δmax = 0.2%L = 40mm (meeting 0.15%-0.3% of the cantilever section length), and the curvature radius change gradient of the end 1 / 3 section (about 6.7m) is controlled within 5% / m.

[0109] During the component processing stage of the cantilever section, a preset pre-camber curve is formed through mechanical cold bending and thermal correction processes.

[0110] Install the positioning device 20:

[0111] A positioning device 20 is installed at the cantilevered steel column node. The positioning device 20 includes a fixture 21, a rotating platform 22, and a laser tracking target 23. The platform of the rotating platform 22 has three degrees of freedom of translation in the X, Y, and Z axes (for example, a single-axis adjustment accuracy of ±0.3mm) and a rotational degree of freedom about the Z axis (for example, an accuracy of ±0.1°).

[0112] The laser tracking target 23 is set on the top of the platform of the rotating table 22. The positioning error of the laser tracking target 23 is controlled within the range of ±1.5mm / 100m. The design coordinates of the cantilever end are used as the reference point to establish a dynamic coordinate system (the X axis is along the cantilever length direction, the Y axis is vertically upward, and the Z axis is perpendicular to the cantilever plane).

[0113] Dual-machine collaborative lifting and attitude adjustment:

[0114] A master-slave control mode is used for dual crane lifting: the master crane (e.g. a 200t crawler crane) bears 75% of the load (approximately 112.5t), and the slave crane (e.g. a 150t truck crane) bears 25% of the load (approximately 37.5t). Both slings are equipped with inertial navigation modules and tension sensors.

[0115] During the hoisting process, the inertial navigation module provides real-time feedback of the spatial coordinates of the cantilevered section components (X, Y, Z error ≤ 2mm) at a frequency of 50Hz. Combined with the point cloud data collected by the ground laser scanner (accuracy ±1mm), it is dynamically compared with the BIM model. When the deviation exceeds 5mm, the rotating table 22 is triggered to automatically correct it.

[0116] Environmental parameter compensation:

[0117] Install anemometers (e.g., collection frequency 10 times / second) and temperature sensors (e.g., spacing 1.5m, meeting the requirement of ≤2m) to monitor environmental parameters in real time: for example, the average wind speed on the construction day is 3m / s, and the temperature gradient is 2°C / m (the temperature difference between the top and bottom of the cantilevered section).

[0118] A "wind speed-temperature-deformation" mapping model is established through a neural network algorithm, and compensation instructions are generated through reverse calculation to drive the rotating table 22 to perform millimeter-level corrections (for example, the thermal expansion deformation compensation caused by temperature is +3mm, and the lateral offset compensation caused by wind speed is -2mm).

[0119] Distributed support device 30 activated:

[0120] After the cantilever section is in place, the distributed jacking device 30 is started. The distributed jacking device 30 includes 8 groups of pressure self-sensing hydraulic cylinders 31 and detachable articulated supports 32.

[0121] The support point spacing is calculated according to the formula Calculation, where K=0.3L=6m, the maximum bending moment at the cantilever root M max =3000kN·m, design bending moment at each point M i Finite element analysis determined that nonlinear distributed supports were formed (e.g., end support spacing 8m, middle spacing 5m, root spacing 3m), satisfying L = 0.25~0.35 times the cantilever length.

[0122] Welding stress monitoring and gradient cooling:

[0123] Fiber Bragg grating sensors are embedded in the welding nodes to monitor stress distribution in real time, and welding is suspended when the local stress exceeds 10% of the design value.

[0124] After welding is completed, gradient cooling is adopted. The temperature can be first lowered from the welding temperature (about 500℃) to 250℃ at a rate of 15℃ / min, maintained for 10 minutes to eliminate residual stress, and then lowered to ambient temperature (for example, 20℃) at a rate of 5℃ / min to avoid stress concentration caused by sudden cooling.

[0125] Phased uninstallation and monitoring:

[0126] The unloading is carried out in three stages, with each stage releasing approximately 30% of the load (for example, the total load is 150t, and 45t is released in the first stage). The interval between adjacent stages is 4h to ensure the stability of the structural stress.

[0127] Monitor deformation in real time during unloading: for example, control the deflection change rate to 0.3mm / h (≤0.5mm / h) and the stress fluctuation amplitude to ≤8% (≤10%). If the monitoring data is abnormal, suspend unloading, analyze the cause, and adjust the plan.

[0128] After the unloading is completed and the deformation is stable, the distributed supporting device 30 and the temporary supporting assembly are modularly dismantled.

[0129] In summary, the above method improves the positioning accuracy of the cantilever steel structure during hoisting, reduces positioning offset at the cantilever end, and effectively solves the challenges of stability and precision control during high-altitude hoisting. Furthermore, the construction period is shorter than traditional methods, the amount of temporary support required is reduced, and it can meet the construction requirements of long-span steel structures in complex environments.

[0130] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0131] The above embodiments merely illustrate several implementation methods of the present application, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the inventive concept of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for aerial hoisting of a cantilevered steel structure, characterized by: The following steps are involved: Step S1: presetting an anti-deformation compensation value during the component processing stage of the cantilever section to form a cantilever section steel structure with a pre-camber curve, wherein the cantilever section steel structure has a cantilever root and a cantilever end; Step S2, installing a positioning device at the cantilever root, wherein the positioning device includes a fixture, a rotating table, and a laser tracking target, and establishing a dynamic coordinate system with the cantilever end as a reference point; Step S3: Using a hoisting system to adjust the aerial posture of the cantilevered steel structure, and using an inertial navigation module attached to a sling of the hoisting system to provide real-time feedback on the spatial coordinates of the cantilevered steel structure, and performing a dynamic deviation comparison with the design model in combination with the scanned coordinate data of the laser tracking target; Step S4, setting an environmental parameter compensation module and synchronously collecting wind speed data and temperature gradient data, wherein the environmental parameter compensation module controls the rotating stage to perform millimeter-level closed-loop correction of the rotation angle according to the wind speed data and the temperature gradient data; Step S5: activating a distributed jacking device after the cantilever section is in place, the distributed jacking device comprising a plurality of correspondingly arranged pressure self-sensing hydraulic cylinders and detachable articulated supports, each of the pressure self-sensing hydraulic cylinders being connected to the cantilever section via the corresponding detachable articulated support to form a segmented temporary support assembly, wherein the spacing between the support points of the cantilever section supported by adjacent pressure self-sensing hydraulic cylinders ranges from 0.25 times to 0.35 times the cantilever length and is nonlinearly distributed; Step S6, monitoring welding stress distribution by using a fiber grating sensor embedded in the cantilevered section, and implementing multi-level welding fixation using a gradient cooling method; Step S7, after completing the installation and fixation of the cantilever section steel structure, release the load of the distributed supporting device in stages, and simultaneously monitor the deformation of the cantilever section steel structure until it reaches the designed stress state, and then remove the segmented temporary support assembly.

2. The aerial hoisting method for a cantilevered steel structure according to claim 1 is characterized in that: The steps of forming the cantilevered steel structure with a pre-camber curve include: Finite element simulation was performed based on 1.2 to 1.5 times the design load of the cantilever section, and the maximum deformations δx, δy, and δz along the X, Y, and Z axes were extracted; Generate a spatial compensation curve according to the proportional relationship of (0.8~0.9)δx, (1.0~1.1)δy, and (1.2~1.3)δz; Presetting the anti-deformation compensation value according to the space compensation curve during the component processing stage of the cantilever section; According to the anti-deformation compensation value, the cantilever section steel structure is provided with a pre-supplied curve.

3. The aerial hoisting method for a cantilevered steel structure according to claim 1 is characterized in that: In step S2, the rotating stage has three degrees of freedom of translation in the X, Y, and Z axes and a degree of freedom of rotation about the Z axis.

4. The aerial hoisting method for a cantilevered steel structure according to claim 1 is characterized in that: In step S3, the hoisting system is a dual-machine collaborative hoisting system, which includes a master crane and a slave crane. The dual-machine collaborative hoisting system adopts a master-slave control mode, wherein the master crane bears the main load, and the slave crane uses a tension sensor to provide real-time feedback on the tension value of the sling.

5. The aerial hoisting method for a cantilevered steel structure according to claim 1 is characterized in that: In step S4, the environmental parameter compensation module controls the rotating stage to perform millimeter-level closed-loop correction according to the wind speed data and the temperature gradient data, including: A neural network algorithm is used to establish an environmental parameter-deformation mapping model, wherein the environmental parameters include the wind speed data and the temperature gradient data; Using the environmental parameter-deformation mapping model, finite element reverse calculation is performed to generate dynamic compensation instructions; The control system controls the rotating stage to perform millimeter-level closed-loop correction of the rotation angle according to the dynamic compensation instruction.

6. The aerial hoisting method for a cantilevered steel structure according to claim 1 is characterized in that: In step S5, the distribution rule of the distance L between the support points satisfies: Wherein, Li is the reinforcement spacing at point i, K=(0.28~0.32)L, L is the total length of the cantilever section, Mi is the design bending moment value at point i, and Mmax is the maximum bending moment value of the cantilever section corresponding to the cantilever root.

7. The aerial hoisting method for a cantilevered steel structure according to claim 1 is characterized in that: In step S6, the gradient cooling method includes: first cooling to a preset temperature range at a preset rate and keeping the temperature for a preset time, and then cooling to ambient temperature at another slower preset rate.

8. The aerial hoisting method for a cantilevered steel structure according to claim 1, characterized in that: In step S7, when releasing the load of the distributed supporting device in stages, the unloading sequence is implemented in multiple stages, and the load released in each stage does not exceed 1 / 3 of the total load.

9. The aerial hoisting method for a cantilevered steel structure according to any one of claims 1 to 8, characterized in that: Before step S1, the method further includes the following steps: arranging a distributed thin film pressure sensor on the surface of the cantilevered section, wherein the distributed thin film pressure sensor includes a film material, a resistance strain gauge array, and a temperature compensation unit, wherein the resistance strain gauge array and the temperature compensation unit are both arranged on the film material; The distribution density of distributed thin film pressure sensors meets the following requirements: Among them, N sensor is the total number of effective sensing units in the resistance strain gauge array, A is the monitoring area, and ζ is the minimum density threshold.

10. The aerial hoisting method of a cantilevered steel structure according to claim 1, characterized in that: The maximum compensation amount of the pre-camber curve is: The curvature radius variation gradient of the cantilevered steel structure corresponding to the cantilevered end section satisfies: Wherein, ξ is a dimensionless coefficient related to the cross-sectional shape coefficient and load distribution of the cantilever section, L is the total length of the cantilever section, ΔR is the change in curvature radius, Δs is the arc length increment, and R0 is the initial curvature radius.

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