Standard segment cantilever assembly construction method of double-side box steel-concrete composite beam
By using a coupled solver of hydraulic cylinders and real-time wind and temperature field data to dynamically adjust the posture of the main steel beam during the cantilever assembly of the double-sided box girder of the cable-stayed bridge, the problem of posture deviation caused by wind load and temperature gradient during the hoisting process of the main steel beam was solved, thus improving construction efficiency and structural safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GUIZHOU HIGHWAY ENG GRP
- Filing Date
- 2026-02-11
- Publication Date
- 2026-06-19
Smart Images
Figure CN121675332B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of intelligent bridge construction technology, and in particular to a cantilever assembly construction method for standard segments of double-sided box girder steel-concrete composite beams. Background Technology
[0002] In the cantilever assembly of double-box steel-concrete composite girders for cable-stayed bridges, the hoisting accuracy of standard steel main girder segments directly affects structural safety and alignment control. Traditional hoisting methods expose the steel main girder to transient wind loads and solar temperature gradients during hoisting, easily leading to positional deviations. These deviations often cause localized stress concentrations; for example, the stress at the junction of the box girder web and top plate may exceed the allowable value for the steel, creating a risk of buckling. This necessitates interrupting the hoisting process for manual adjustment. Summary of the Invention
[0003] This invention provides a cantilever assembly construction method for standard segments of double-sided box girder steel-concrete composite beams, which can effectively solve the problems in the background art.
[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0005] The cantilever assembly construction method for standard segments of double-sided box girder steel-concrete composite beams includes:
[0006] The standard steel main beam is hoisted through at least four lifting points. The steel main beam and the hoisting slings are connected at the lifting points by hydraulic cylinders. The axis of the hydraulic cylinders is perpendicular to the top surface of the top plate of the steel main beam.
[0007] Input the structural parameters of the steel main beam, real-time wind field data, and real-time temperature field data, and calculate the spatial deviation of the steel main beam through a coupled solver of structure, wind, and temperature.
[0008] Based on the spatial deviation, the pre-compensation extension / retraction amount of each hydraulic cylinder is calculated in reverse.
[0009] Control each of the hydraulic cylinders to adjust the position of the steel main beam according to the pre-compensated extension and retraction amount;
[0010] The position and orientation of the main steel beam are monitored during the hoisting process. When the deviation between the measured position and orientation and the target position and orientation exceeds the set deviation, the coupled solver is updated based on the real-time wind field data and real-time temperature field data.
[0011] Furthermore, the coupled solver includes:
[0012] The wind load calculation unit calculates the wind pressure distribution acting on the surface of the steel main beam based on the real-time wind field data.
[0013] The temperature field analysis unit calculates the transient thermal deformation of the steel main beam section caused by solar radiation based on the real-time temperature field data.
[0014] The structural response unit couples the wind pressure distribution with transient thermal deformation and solves for the spatial deviation using a finite element model.
[0015] Furthermore, the structural response unit couples the wind pressure distribution with transient thermal deformation, and solves for the spatial deviation using a finite element model, including:
[0016] A hybrid mesh model was constructed based on the design parameters of the steel main beam, and constraints were set at the hydraulic cylinder connection points.
[0017] The wind pressure distribution is transformed into the equivalent wind load on the nodes of the hybrid grid model, and the transient thermal deformation is transformed into the initial strain field of the grid cells of the hybrid grid model.
[0018] The dynamic response of the steel main beam is solved iteratively using an implicit integration algorithm.
[0019] Extract the linear and angular displacement deviations of the control points at the beam ends.
[0020] Furthermore, the wind pressure distribution is transformed into an equivalent wind load on the nodes of the hybrid grid model, specifically by weighting the wind pressure distribution to the nodes according to the surface area of the grid cells.
[0021] Furthermore, the dynamic response includes:
[0022] The factors include the resistance of the steel main beam mass to acceleration, the energy consumption caused by the structure itself and air resistance, the ability of steel to resist deformation, and the combined effect of wind load and temperature strain.
[0023] Furthermore, updating the coupled solver based on the real-time wind field data and real-time temperature field data includes:
[0024] Based on the current extension / retraction state of the hydraulic cylinder, reset the constraints set at the hydraulic cylinder connection points in the hybrid mesh model.
[0025] Furthermore, the coupled solver also includes:
[0026] The historical data analysis unit calls up historical extreme climate data stored in the local database and calculates the probability of sudden wind and temperature change in the current construction area within a preset time period based on a probability statistical model.
[0027] When the probability of sudden wind or temperature change exceeds the set threshold, it is determined that an abnormal scenario has been entered, and the updating of the coupled solver is paused.
[0028] In the aforementioned abnormal scenario, a graded response is triggered based on the spatial deviation, including:
[0029] If the spatial deviation is greater than 50mm, a stop hoisting command will be generated.
[0030] If the spatial deviation is less than 10mm and less than or equal to 50mm, the adjustment frequency of the hydraulic cylinder should be increased.
[0031] Furthermore, based on a probabilistic statistical model, the probability of sudden winds and the probability of sudden temperature changes in the current construction area within a preset time period are calculated, including:
[0032] Centered on the construction location point, the radius of the geographic fence is dynamically determined according to the terrain type. Historical data of the same period within the fence radius of the monitoring stations and the time period within ±2 to ±4 days of the current construction date are extracted from the local meteorological database.
[0033] For historical wind speed data, extract the peak wind speed of 2 to 4 seconds within each 8 to 15 minute time window to form a sequence of extreme values of sudden wind load;
[0034] For historical temperature data, extract the minute-by-minute sampling values during continuous construction periods of 4 to 6 hours, calculate the absolute value of the temperature difference between adjacent 8 to 12 minute windows, and construct a temperature change intensity sequence.
[0035] Based on the extreme value sequence of the sudden wind load, the probability of sudden wind in the next 1 to 3 hours is calculated by using a generalized Pareto distribution model.
[0036] Based on the temperature change intensity sequence, a Gaussian mixture model is used to model and calculate the probability of temperature change in the next 1 to 3 hours.
[0037] Furthermore, a strain gauge array is installed on the exposed section of the piston rod of the hydraulic cylinder to collect stress values at at least three locations uniformly distributed in the circumferential direction of the piston rod;
[0038] Calculate the variance of each stress value. If the variance exceeds a set variance threshold, simultaneously increase the pressure in the rod-side and rodless-side chambers of the hydraulic cylinder.
[0039] Furthermore, for every 1 MPa increase in variance... 2 The pressure in the rod chamber and the rodless chamber are simultaneously increased to increase the base pressure by 1 to 3 MPa.
[0040] When the ambient temperature exceeds 35°C, the increase in the basic pressure is multiplied by a compensation coefficient, which is between 0.4 and 0.8.
[0041] The single pressure increase is less than 5% of the rated working pressure of the hydraulic cylinder, and the cumulative pressure value is less than 1.1 times the rated working pressure.
[0042] The technical solution of this invention can achieve the following technical effects:
[0043] This invention, by arranging hydraulic cylinders vertically to the top plate, can directly resist the deformation of the steel main beam under wind and temperature loads. The hydraulic cylinders connect the steel main beam to the hoisting slings, and the spatial deviation is calculated based on real-time wind and temperature field data. This allows the hydraulic cylinders to pre-compensate and extend, dynamically adjusting the steel main beam's posture. This effectively suppresses posture deviations induced by wind loads and temperature gradients, thus preventing local stress concentration and buckling risks at the junction of the box girder web and top plate. It also reduces the need for hoisting interruptions, improving construction efficiency and structural safety. Attached Figure Description
[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0045] Figure 1 A flowchart of the cantilever assembly construction method for standard segments of double-sided box girder steel-concrete composite beam;
[0046] Figure 2 Here is a framework diagram of the coupled solver;
[0047] Figure 3 A flowchart for solving spatial deviation using a finite element model;
[0048] Figure 4 This is a flowchart of a tiered response for abnormal scenarios. Detailed Implementation
[0049] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.
[0050] like Figure 1 As shown, the cantilever assembly construction method for standard segments of double-sided box girder steel-concrete composite beams includes:
[0051] S1: The standard steel main beam is hoisted through at least 4 lifting points. The steel main beam and the hoisting slings are connected at the lifting points by hydraulic cylinders. The axis of the hydraulic cylinder is perpendicular to the top surface of the top plate of the steel main beam.
[0052] S2: Input the structural parameters of the steel main beam, real-time wind field data, and real-time temperature field data, and calculate the spatial deviation of the steel main beam through the coupled solver of structure, wind, and temperature.
[0053] S3: Based on the spatial deviation, calculate the pre-compensation extension / retraction amount of each hydraulic cylinder in reverse;
[0054] S4: Control each hydraulic cylinder to adjust the position of the main steel beam according to the pre-compensated extension / retraction amount;
[0055] S5: Monitors the position and orientation of the main steel beam during hoisting. When the deviation between the measured position and orientation and the target position and orientation exceeds the set deviation, the coupled solver is updated based on real-time wind field data and real-time temperature field data. The set deviation can be preset according to the actual working conditions.
[0056] In this invention, spatial deviation includes the offset of the steel main beam's center of gravity in the three-dimensional coordinate system, specifically longitudinal, lateral, and vertical offsets, as well as the rotation angles of the steel main beam around the three-dimensional coordinate axes, specifically pitch, roll, and yaw angles. Spatial deviation is the combined deformation caused by its own weight, wind, and temperature, directly determining the leveling amount of the hydraulic cylinder. In embodiments of this invention, monitoring the position and attitude of the steel main beam during hoisting can be achieved using existing equipment such as tilt sensors and total station targets.
[0057] During implementation, by arranging the hydraulic cylinders vertically to the top plate, the deformation of the steel main beam under wind and temperature loads can be directly resisted by the hydraulic cylinders. The steel main beam is connected to the hoisting slings by the hydraulic cylinders, and the spatial deviation is calculated based on real-time wind and temperature field data. This drives the hydraulic cylinders to pre-compensate and extend to dynamically adjust the posture of the steel main beam, effectively suppressing the posture deviation induced by wind load and temperature gradient. This prevents problems such as local stress concentration and buckling risk at the junction of the box girder web and top plate, reduces the need for hoisting interruptions, and improves construction efficiency and structural safety.
[0058] As a preferred embodiment of the above, such as Figure 2 As shown, the coupled solver includes:
[0059] The wind load calculation unit calculates the wind pressure distribution acting on the surface of the steel main beam based on real-time wind field data; the temperature field analysis unit solves for the transient thermal deformation of the steel main beam section caused by solar radiation based on real-time temperature field data; and the structural response unit couples the wind pressure distribution with the transient thermal deformation and solves for the spatial deviation through a finite element model.
[0060] In this preferred scheme, real-time wind field data includes wind speed, wind direction, and turbulence intensity. Computational fluid dynamics (CFD) fluid-structure interaction methods or standard wind load formulas are used to solve for the normal wind pressure distribution in each region of the steel main beam surface. In specific implementation, the steel main beam surface is discretized into micro-elements, and the wind pressure value of each micro-element is calculated according to Bernoulli's equation, ultimately forming a spatially continuous wind pressure field. Real-time temperature field data includes ambient temperature, solar radiation intensity, and steel surface temperature monitoring values. A transient heat conduction equation for the steel main beam cross-section is established. Specifically, the non-uniform thermal boundary conditions caused by changes in solar azimuth angle can be solved using the finite difference method, outputting the cross-sectional temperature gradient distribution and the resulting transient thermal deformation.
[0061] The structural response element couples the wind pressure distribution and transient thermal deformation field into the finite element model of the steel main beam. Specifically, the finite element model can be constructed based on the beam-shell hybrid element.
[0062] Through the implementation of the above optimized schemes, the wind load calculation unit quantifies wind-induced dynamic interference, avoiding the simplification error of the traditional static wind load coefficient; the temperature field analysis unit accurately captures the asymmetric thermal deformation caused by solar radiation, such as the expansion rate of the top plate of a single-sided box girder being higher than that of the web plate; the structural response unit couples the two with the self-weight effect, and reflects the comprehensive deformation trend of the steel main beam in a complex environment through the finite element model. The coupling mechanism improves the prediction accuracy of spatial deviation, making the calculation of the pre-compensation expansion and contraction of the hydraulic cylinder more in line with the actual working conditions.
[0063] As a preferred embodiment of the above, such as Figure 3 As shown, the structural response unit couples wind pressure distribution with transient thermal deformation, and the spatial deviation is solved using a finite element model, including:
[0064] A1: Construct a hybrid mesh model based on the design parameters of the main steel beam, and set constraints at the hydraulic cylinder connection points;
[0065] A2: Transform the wind pressure distribution into equivalent wind loads on the nodes of the hybrid mesh model, preserving the spatial distribution characteristics of the wind loads; and transform transient thermal deformation into the initial strain field of the mesh elements of the hybrid mesh model, characterizing the mechanical effects of the temperature gradient.
[0066] A3: The dynamic response of the steel main beam is solved iteratively using an implicit integral algorithm;
[0067] A4: Extract the linear and angular displacement deviations of the control points at the beam ends.
[0068] In step A1, a hybrid beam-shell mesh model is constructed based on the actual design parameters of the main steel beam. This accurately represents the geometric characteristics of the double-sided box girder section, such as the gradual change zone of web thickness and the stiffening ribs of the top plate. Simultaneously, constraint conditions are set at the hydraulic cylinder lifting points to ensure that the boundary conditions are consistent with the actual stress state, avoiding the simplification errors of local stiffness in traditional pure beam element models. In step A2, direct coupling of wind and temperature physical quantities with the structural model is achieved, avoiding the error propagation caused by intermediate simplifications.
[0069] In step A3, an implicit time integration algorithm is used to iteratively calculate the dynamic response of the steel main beam. This efficiently handles the quasi-static hoisting process while ensuring numerical stability, overcoming the dependence of explicit algorithms on small time steps and improving computational efficiency. The implicit algorithm effectively suppresses high-frequency vibration numerical divergence through a global iterative convergence mechanism. During hoisting, sudden wind impacts or abrupt changes in sunlight direction may induce high-frequency flutter in the steel main beam. The implicit algorithm allows for practical engineering step sizes greater than or equal to 0.1 seconds, ensuring stable output of effective solutions even under severe environmental disturbances and preventing the control system from losing control due to solution collapse. Finally, in step A4, the linear and angular displacement deviations of the beam end control points are extracted, directly outputting the spatial deviation parameters corresponding to the hydraulic cylinder posture adjustment, ensuring the executability of the pre-compensation command.
[0070] As a preferred embodiment of the above, in step A2, the wind pressure distribution is transformed into equivalent wind loads on the nodes of the hybrid grid model. Specifically, the wind pressure distribution is weighted and distributed to the nodes according to the surface area of the grid cells. In this preferred scheme, for specific areas on the surface of the steel main beam, such as the corner of the box girder, the wind pressure is distributed according to the actual surface area of the grid cells. This avoids the stress calculation deviation caused by the traditional average distribution method in complex geometric areas. The weighted distribution ensures that the total wind load is strictly conserved before and after discretization, preventing wind-induced torque prediction errors caused by simplified transmission.
[0071] Regarding the dynamic response described in step A3 of the above embodiments, this preferred embodiment specifically includes: the resistance of the steel main beam mass to acceleration, the energy consumption formed by the structure itself and air resistance, the ability of steel to resist deformation, and the combined effect of wind load and temperature strain.
[0072] In cantilever assembly construction, the steel main beam is in a free-suspension state, and its posture is subject to multiple dynamic disturbances such as wind-induced vibration, thermal inertia effects, and hydraulic cylinder feedback forces. Solving the dynamic response requires accurately quantifying the transient behavior of the structure under time-varying environmental loads. In the above optimized scheme, by taking into account mass inertia, damping energy dissipation, material stiffness, and wind-temperature coupled excitation, the entire process from disturbance to stability is realistically simulated, providing an advanced control window for hydraulic cylinder pre-compensation.
[0073] In the above embodiments, linear displacement and angular displacement deviations are extracted after solving the dynamic response. The linear displacement deviation directly maps to the synchronous lifting and lowering of the hydraulic cylinders; for example, vertical offset requires equal extension and retraction of all hydraulic cylinders. The angular displacement deviation corresponds to the differential action rules of the hydraulic cylinder groups; for example, pitch angle deviation requires opposite extension and retraction of the hydraulic cylinders at the beam end and root. This displacement parameter system can be instantly converted into hydraulic cylinder extension and retraction commands.
[0074] During the cantilever assembly construction, the real-time extension and retraction state of the hydraulic cylinder will change the boundary constraint stiffness of the steel main beam. Therefore, as a preferred embodiment, the coupled solver is updated based on real-time wind field data and real-time temperature field data, including: resetting the constraint conditions set at the hydraulic cylinder connection points in the hybrid mesh model based on the current extension and retraction state of the hydraulic cylinder.
[0075] Specifically, the "based on the current extension / retraction state of the hydraulic cylinder" refers to updating the finite element boundary conditions based on the real-time physical displacement and corresponding mechanical state of the hydraulic cylinder piston rod. This preferred solution dynamically updates the coupled solver based on real-time wind field and temperature field data, and simultaneously resets the constraint conditions of the hydraulic cylinder connection points in the hybrid mesh model, fundamentally solving the key problem of mismatch between the traditional static constraint model and the actual working state of the hydraulic cylinder.
[0076] Thermal expansion of the hydraulic cylinder due to solar radiation and pressure fluctuations caused by sudden wind loads can lead to drift in the equivalent support stiffness of the hydraulic cylinder. Using a fixed constraint model may amplify the deformation prediction error. By resetting the constraint conditions in real time, the finite element model can accurately reflect the actual boundary characteristics of the hydraulic cylinder. Specifically, this includes automatically correcting the displacement of constraint points caused by thermal expansion under temperature gradients and matching the changes in hydraulic cylinder damping parameters in real time during wind-induced vibrations. This deeply couples the working state of the hydraulic cylinder with the structural response model, thereby improving the effective execution rate of the hydraulic cylinder's pre-compensation actions.
[0077] As a preferred embodiment of the above, the coupled solver further includes: a historical data analysis unit, which calls historical extreme climate data stored in a local database and calculates the probability of sudden wind and temperature change in the current construction area within a preset time period based on a probabilistic statistical model.
[0078] like Figure 4 As shown, when the probability of a sudden gust of wind or a sudden change in temperature exceeds a set threshold, an abnormal scenario is identified, and the updating of the coupled solver is paused. In the abnormal scenario, a graded response is triggered based on the spatial deviation, including:
[0079] If the spatial deviation is greater than 50mm, a stop hoisting command will be generated.
[0080] If the spatial deviation is less than 10mm and less than or equal to 50mm, increase the adjustment frequency of the hydraulic cylinder.
[0081] Under normal operating conditions, advanced control is achieved by relying on a high-precision dynamic model. However, in this preferred scheme, when extreme weather causes the model to become unstable, it automatically switches to a low-level protection mechanism that directly responds to displacement. By pausing the updates of the coupled solver, it avoids the risk of abnormal environmental data contaminating the model and prevents malfunctions. At the same time, the hierarchical response with displacement as the sole criterion ensures the absolute reliability of control commands. This avoids the project schedule loss caused by excessively conservative shutdowns and eliminates the risk of loss of control when the model fails. Actual measurements show that the structural accident rate under sudden climate change conditions is reduced to zero.
[0082] As a preferred embodiment of the above, the probability of sudden wind and the probability of sudden temperature change in the current construction area within a preset time period are calculated based on a probabilistic statistical model, including:
[0083] Centered on the construction location point, the radius of the geographic fence is dynamically determined according to the terrain type, for example, 1 kilometer for flat land and 2 kilometers for valleys or water bodies; historical data of the same period within the fence radius of the monitoring stations are extracted from the local meteorological database, matching the time period within ±2 to ±4 days of the current construction date, specifically historical data of the same period within ±3 days of the current construction date.
[0084] For historical data from the same period, the peak wind speed for 2 to 4 seconds within each 8 to 15-minute time window is extracted to form a sequence of extreme values for sudden wind loads. Specifically, the peak wind speed for 3 seconds within each 10-minute time window is extracted to form a sequence of extreme values for sudden wind loads. For historical temperature data, the sampled values for each minute during a continuous 4 to 6-hour construction period are extracted, and the absolute value of the temperature difference between adjacent 8 to 12-minute windows is calculated to form a sequence of sudden temperature change intensity. Specifically, the sampled values for each minute during a continuous 5-hour construction period are extracted, and the absolute value of the temperature difference between adjacent 10-minute windows is calculated to form a sequence of sudden temperature change intensity.
[0085] Based on the extreme value sequence of sudden wind load, the probability of sudden wind in the next 1 to 3 hours is calculated by using a generalized Pareto distribution model; while based on the intensity sequence of sudden temperature change, the probability of sudden temperature change in the next 1 to 3 hours is calculated by using a Gaussian mixture model.
[0086] In cantilever assembly construction, the generalized Pareto distribution modeling technique is used to process the extreme value sequence of gust loads for calculating the probability of gusts. Specifically, by analyzing the statistical characteristics of historical extreme wind speeds, the predictive ability of traditional models for rare strong wind events is improved. This method is particularly suitable for capturing the instantaneous increase in wind speed caused by terrain such as canyons. In this way, gust events that may endanger construction safety can be identified in advance, and the effective warning time can be extended.
[0087] For calculating the probability of sudden temperature changes, the temperature difference intensity sequence analysis method based on the Gaussian mixture model can effectively distinguish the inherent laws of temperature drastic changes under different weather patterns; by identifying abnormal temperature fluctuations caused by sudden changes in the local environment, it solves the problem of insufficient adaptability of traditional single distribution models to complex climate patterns; the generated probability of sudden temperature changes can actively trigger the thermal compensation program of the hydraulic system, simultaneously offsetting the impact of structural thermal deformation and preventing the failure of the hydraulic sealing system.
[0088] The collaborative mechanism of the two models is specifically designed for combined extreme climate conditions. By integrating the coupled risk characteristics of sudden winds and abrupt temperature changes, it ensures that hydraulic cylinder control commands remain stably executed under severe weather conditions, guaranteeing that the assembly alignment of the cantilever end of the steel beam remains under control. Specifically, the generalized Pareto distribution modeling can be achieved through the over-threshold sampling method, and the Gaussian mixture modeling can be solved using the expectation-maximization algorithm. The specific process employs existing technical means.
[0089] As a preferred embodiment of the above, a strain gauge array is set on the exposed section of the piston rod of the hydraulic cylinder to collect stress values at at least three locations uniformly distributed in the circumferential direction of the piston rod; specifically, four stress values can be obtained; the variance of each stress value is calculated, and if the variance exceeds a set variance threshold, the pressure in the rod chamber and the rodless chamber of the hydraulic cylinder is increased simultaneously.
[0090] Because the hydraulic cylinder is connected to the lifting slings and the main steel beam at both ends, it will inevitably bear bending moment under normal circumstances. However, in the corresponding scenario, a reasonable bending moment has been fully considered in the structural design and selection. In this preferred scheme, multi-directional stress values are collected in real time by a strain gauge array evenly distributed around the circumference of the exposed section of the piston rod, constructing a dynamic monitoring mechanism for the eccentric load state of the hydraulic system. This aims to calculate the stress variance at each measuring point to quantify the balance of force on the piston rod. When the variance exceeds a threshold, it directly indicates that the hydraulic cylinder is bearing an abnormal lateral bending moment. At this time, the pressure in the rod chamber and the rodless chamber is increased simultaneously. Under the premise that the total thrust remains unchanged, the piston rod axis deflection is forcibly corrected through bidirectional hydraulic pressure compensation. Through the above technical measures, the unilateral wear of the sealing ring caused by the radial deflection of the piston rod can be reduced.
[0091] As a preferred embodiment of the above, for every 1 MPa increase in variance, 2 The pressure in the rod chamber and the rodless chamber is increased synchronously to increase the base pressure by 1 to 3 MPa. When the ambient temperature exceeds 35°C, the base pressure increase is multiplied by a compensation coefficient of 0.4 to 0.8. The single pressure increase is less than 5% of the rated working pressure of the hydraulic cylinder, and the cumulative pressure value is less than 1.1 times the rated working pressure.
[0092] As a preferred approach, the base pressure increase is set to 2 MPa, with a compensation coefficient of 0.6. This preferred scheme enables the hydraulic system to automatically adjust the correction force within 1 to 3 MPa based on the severity of off-center load. A compensation coefficient is introduced for high-temperature conditions to dynamically reduce the pressure increase, mitigating the risk of failure caused by softening of sealing materials and decreased oil viscosity. During implementation, the dual constraints of the single pressure increase limit and the cumulative pressure threshold prevent hydraulic system overload accidents, ensuring the maintenance of the piston rod axial force transmission characteristics under complex and severe operating conditions.
[0093] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.
Claims
1. A method for cantilever assembly of standard segments of double-sided box girder steel-concrete composite beams, characterized in that, include: The standard steel main beam is hoisted through at least four lifting points. The steel main beam and the hoisting slings are connected at the lifting points by hydraulic cylinders. The axis of the hydraulic cylinders is perpendicular to the top surface of the top plate of the steel main beam. Input the structural parameters of the steel main beam, real-time wind field data, and real-time temperature field data, and calculate the spatial deviation of the steel main beam through a coupled solver of structure, wind, and temperature. Based on the spatial deviation, the pre-compensation extension / retraction amount of each hydraulic cylinder is calculated in reverse. Control each of the hydraulic cylinders to adjust the position of the steel main beam according to the pre-compensated extension and retraction amount; The position and orientation of the main steel beam are monitored during the hoisting process. When the deviation between the measured position and orientation and the target position and orientation exceeds the set deviation, the coupled solver is updated based on the real-time wind field data and real-time temperature field data. The coupled solver includes: The wind load calculation unit calculates the wind pressure distribution acting on the surface of the steel main beam based on the real-time wind field data. The temperature field analysis unit calculates the transient thermal deformation of the steel main beam section caused by solar radiation based on the real-time temperature field data. The structural response unit, coupled with the wind pressure distribution and transient thermal deformation, solves for the spatial deviation using a finite element model, including: constructing a hybrid mesh model based on the design parameters of the steel main beam and setting constraints at the hydraulic cylinder connection points; converting the wind pressure distribution into equivalent wind loads on the nodes of the hybrid mesh model; and converting the transient thermal deformation into the initial strain field of the mesh elements of the hybrid mesh model; iteratively solving the dynamic response of the steel main beam using an implicit integration algorithm; and extracting the linear and angular displacement deviations of the beam end control points. Updating the coupled solver based on the real-time wind field data and real-time temperature field data includes: resetting the constraint conditions set at the hydraulic cylinder connection points in the hybrid mesh model based on the current extension and retraction state of the hydraulic cylinder.
2. The cantilever assembly construction method for standard segments of double-sided box girder steel-concrete composite beam according to claim 1, characterized in that, The wind pressure distribution is transformed into an equivalent wind load on the nodes of the hybrid grid model, specifically by weighting the wind pressure distribution to the nodes according to the surface area of the grid cells.
3. The cantilever assembly construction method for standard segments of double-sided box girder steel-concrete composite beam according to claim 1, characterized in that, The dynamic response includes: The factors include the resistance of the steel main beam mass to acceleration, the energy consumption caused by the structure itself and air resistance, the ability of steel to resist deformation, and the combined effect of wind load and temperature strain.
4. The cantilever assembly construction method for standard segments of double-sided box girder steel-concrete composite beam according to claim 1, characterized in that, The coupled solver also includes: The historical data analysis unit calls up historical extreme climate data stored in the local database and calculates the probability of sudden wind and temperature change in the current construction area within a preset time period based on a probability statistical model. When the probability of sudden wind or temperature change exceeds the set threshold, it is determined that an abnormal scenario has been entered, and the updating of the coupled solver is paused. In the aforementioned abnormal scenario, a graded response is triggered based on the spatial deviation, including: If the spatial deviation is greater than 50mm, a stop hoisting command will be generated. If the spatial deviation is less than 10mm and less than or equal to 50mm, the adjustment frequency of the hydraulic cylinder should be increased.
5. The cantilever assembly construction method for standard segments of double-sided box girder steel-concrete composite beam according to claim 4, characterized in that, The probability of sudden winds and temperature changes in the current construction area within a preset time period is calculated based on a probabilistic statistical model, including: Centered on the construction location point, the radius of the geographic fence is dynamically determined according to the terrain type. Historical data of the same period within the fence radius of the monitoring stations and the time period within ±2 to ±4 days of the current construction date are extracted from the local meteorological database. For historical wind speed data, extract the peak wind speed of 2 to 4 seconds within each 8 to 15 minute time window to form a sequence of extreme values of sudden wind load; For historical temperature data, extract the minute-by-minute sampling values during continuous construction periods of 4 to 6 hours, calculate the absolute value of the temperature difference between adjacent 8 to 12 minute windows, and construct a temperature change intensity sequence. Based on the extreme value sequence of the sudden wind load, the probability of sudden wind in the next 1 to 3 hours is calculated by using a generalized Pareto distribution model. Based on the temperature change intensity sequence, a Gaussian mixture model is used to model and calculate the probability of temperature change in the next 1 to 3 hours.
6. The cantilever assembly construction method for standard segments of double-sided box girder steel-concrete composite beam according to claim 1, characterized in that: An array of strain gauges is installed on the exposed section of the piston rod of the hydraulic cylinder to collect stress values at at least three locations uniformly distributed in the circumferential direction of the piston rod. Calculate the variance of each stress value. If the variance exceeds a set variance threshold, simultaneously increase the pressure in the rod-side and rodless-side chambers of the hydraulic cylinder.
7. The cantilever assembly construction method for standard segments of double-sided box girder steel-concrete composite beam according to claim 6, characterized in that, For every 1 MPa increase in variance 2 The pressure in the rod chamber and the rodless chamber are simultaneously increased to increase the base pressure by 1 to 3 MPa. When the ambient temperature exceeds 35°C, the increase in the basic pressure is multiplied by a compensation coefficient, which is between 0.4 and 0.
8. The single pressure increase is less than 5% of the rated working pressure of the hydraulic cylinder, and the cumulative pressure value is less than 1.1 times the rated working pressure.