Large-span wide-width multi-tower partial cable-stayed bridge girder construction method

Abstract

The invention relates to the field of large-span wide-width multi-tower partial cable-stayed bridge girder construction, and discloses a large-span wide-width multi-tower partial cable-stayed bridge girder construction method which comprises the following steps: S1, steel-concrete combined section construction; s2, construction simulation and linear control; S3, large-section steel box girder installation; s4, closure control; s6, anti-sliding verification of the cable saddle; and S7, analyzing the sensitivity of the dead weight, rigidity, stay cable tension error and temperature change parameters of the steel main beam to the line shape of the main beam, and optimizing a construction monitoring scheme based on an analysis result. Compared with the prior art, the large-span wide-width multi-tower partial cable-stayed bridge main beam construction method has the advantages that the controllability and high precision of the whole main beam construction process are achieved by integrating high-precision measurement, intelligent simulation, dynamic monitoring and active control technologies; and the line shape, the internal force state and the structure safety of the finished bridge completely meet the design requirements.

Description

Technical Field

[0001] This invention relates to the field of construction technology for the main beam of a large-span, wide-width, multi-tower partially cable-stayed bridge, specifically to a construction method for the main beam of such a bridge. Background Technology

[0002] Partially cable-stayed bridges are a type of bridge that falls between beam bridges and cable-stayed bridges, combining the advantages of both. With increasing traffic demand, partially cable-stayed bridges with long spans, wide decks, and multi-tower structures are becoming increasingly common. The main beams of these bridges typically employ steel box girders or steel-concrete composite structures, making their construction complex and technically challenging.

[0003] Traditional construction methods mainly face the following technical challenges:

[0004] (1) The quality of the steel-concrete composite section is difficult to control: the composite section has a complex structure, and the concrete pouring is prone to problems such as non-compactness and shrinkage cracks, which affect the integrity and durability of the structure.

[0005] Insufficient accuracy in alignment control: Multi-tower structures have a high degree of static indeterminacy and are sensitive to construction errors. Conventional pre-assembly calculations are insufficient to accurately predict deformation at each stage, which can easily lead to deviations in the bridge alignment and internal force state from the design objectives.

[0006] (2) Difficulty in matching large-segment hoisting: Under the condition of large span, the hoisting of beam segments is greatly affected by wind, waves and temperature, making it extremely difficult to achieve precise high-altitude alignment and interface matching.

[0007] (3) High precision requirements for multi-tower closure: The closure gap changes significantly with temperature. Selecting the appropriate closure time and actively adjusting the closure gap to the design value are the key to ensuring the quality of the completed bridge.

[0008] (4) Complex structural safety verification: The anti-slip safety of the cable saddle and the internal force state of the structure during construction need to be verified by reliable means to ensure construction and operation safety.

[0009] Therefore, there is an urgent need for a high-precision, dynamically adjustable construction method that can ensure the quality of the completed bridge to solve the above problems. Summary of the Invention

[0010] (a) Technical problems to be solved

[0011] The technical problem to be solved by this invention is to propose a construction method for the main girder of a large-span, wide-width, multi-tower partially cable-stayed bridge. This method integrates high-precision measurement, intelligent simulation, dynamic monitoring and active control technologies to achieve controllability and high precision throughout the main girder construction process, ensuring that the bridge alignment, internal force state and structural safety fully meet the design requirements.

[0012] (II) Technical Solution

[0013] To solve the above-mentioned technical problems, the technical solution provided by this invention is: a construction method for the main beam of a large-span, wide-width, multi-tower partially cable-stayed bridge, comprising the following steps:

[0014] S1. Construction of the steel-concrete composite section: In the construction of the steel-concrete composite section between the zero block and the first steel box girder, a high-precision three-dimensional coordinate positioning system is used to control the installation accuracy of the connectors; the composite section is divided into multiple compartments, and high-performance micro-expansion concrete is symmetrically and synchronously injected from bottom to top and from the center to both sides through the pre-set injection channels, and the compressive stress in the compartment is monitored by embedded sensors to ensure the compactness of the composite section;

[0015] S2. Construction Simulation and Alignment Control: A finite element model of the entire main beam construction process is established. A reverse iterative algorithm is adopted, with the target alignment and internal force state of the completed bridge as the benchmark, to back-calculate the manufacturing alignment and installation alignment of the steel box girder at each construction stage. The reverse iterative algorithm uses the least squares method to correct the error between the completed bridge state and the target state, and dynamically updates the alignment instructions of subsequent beam segments.

[0016] S3. Installation of large-segment steel box girders: Large-segment steel box girders are transported to the bridge site by a girder transport vessel and lifted by a hydraulic lifting crane with six degrees of freedom fine adjustment function; the attitude of the girder segments is monitored in real time by GPS-RTK technology and tilt sensors, and the crane automatically corrects its deviation based on the monitoring data to achieve high-precision matching of the girder segment interfaces;

[0017] S4. Closure Control: Monitor the ambient temperature and structural temperature field, establish a deformation prediction model for the closure joint to determine the closure time period; use a bidirectional adjustable jacking device to actively adjust the closure joint spacing in the closure section, and lock the closure section when the structural temperature tends to be stable.

[0018] S5. Tensioning and stress verification of stay cables: The tension force of stay cables during the construction stage was determined by positive iterative calculation and tensioning was carried out; stress monitoring was carried out on the main beam under the maximum cantilever state and the completed bridge state, and the structural safety was verified by comparing the measured data with the finite element model results;

[0019] S6. Cable Saddle Anti-Slip Verification: The cable stays are tensioned using a full-scale test model to create a tension difference between the two ends. The slippage of the cable stays in the cable saddle area is measured to verify whether its anti-slip capability meets the design requirements.

[0020] S7: Analyze the sensitivity of the steel main beam's self-weight, stiffness, cable tensioning error, and temperature change parameters to the main beam's alignment, and optimize the construction monitoring scheme based on the analysis results.

[0021] As an improvement, in step S2, when establishing the finite element model, BIM technology is integrated to establish a digital twin model of the entire construction process of the main beam.

[0022] As an improvement, in step S4, the closure time period is selected during a period of day when the temperature changes less and the prediction model shows the lowest rate of change in the closure opening length.

[0023] As an improvement, in step S4, the pushing force and displacement of the bidirectional adjustable jacking device are precisely controlled according to the output command of the closure joint deformation prediction model.

[0024] As an improvement, in step S5, the manufacturing profile and installation profile of the steel main beam are calculated using the tangential displacement method or the zero initial displacement method.

[0025] As an improvement, before hoisting in step S3, three-dimensional laser scanning technology is used to obtain the actual geometric shape of the installed beam segment, which is used to assist in the subsequent installation alignment adjustment of the beam segment.

[0026] As an improvement, during construction, sensors installed on construction equipment and key parts of the structure are used to collect data in real time to dynamically identify and assess the risks of large floating crane overturning and uncontrolled beam hoisting; when the assessment indicators exceed the preset threshold, the system will automatically alarm.

[0027] (III) Beneficial Effects

[0028] The advantages of this invention compared to the prior art are:

[0029] (1) By using compartmentalized design, symmetrical synchronous injection of high-performance micro-expansion concrete and real-time monitoring of compressive stress, the density and uniformity of concrete injection are effectively guaranteed, the risk of shrinkage cracks is significantly reduced, and the integrity and durability of key connection areas are guaranteed from the source.

[0030] (2) The reverse iterative algorithm with the ideal state of the completed bridge as the target is adopted, and the least squares method is introduced for closed-loop feedback correction, so that the linear control strategy has foresight and dynamic adaptability, can effectively predict and compensate for deviations caused by various factors, and significantly improve the control accuracy of the construction process of multi-tower statically indeterminate structures and the consistency between the completed bridge state and the design target.

[0031] (3) Relying on the intelligent hoisting system with six degrees of freedom fine adjustment function, it integrates real-time monitoring technologies such as GPS-RTK, tilt sensing and three-dimensional laser scanning, and realizes accurate perception of beam segment attitude and automatic correction of hoisting, which greatly improves the accuracy, efficiency and safety of large segment docking in harsh high-altitude working environment.

[0032] (4) Based on the temperature monitoring and deformation prediction model, the timing of closure is scientifically selected, and the spacing of the closure opening is actively adjusted by using a bidirectional adjustable jacking device, changing "passive waiting" to "actively creating" closure conditions, ensuring the connection of the closure segment under ideal conditions, effectively improving the bridge alignment and reducing additional internal forces.

[0033] (5) By comparing and analyzing the stress monitoring and simulation results throughout the construction process, and by conducting full-scale model tests to verify the anti-slip performance of the cable saddle, dual guarantees were provided for the key performance of the structure from both numerical simulation and physical testing dimensions, which greatly improved the safety and reliability of the construction process and the operation of the completed bridge. Detailed Implementation

[0034] A construction method for the main girder of a large-span, wide-width, multi-tower partially cable-stayed bridge includes the following steps:

[0035] S1. Construction of the steel-concrete composite section: In the construction of the steel-concrete composite section between the zero block and the first steel box girder, a high-precision three-dimensional coordinate positioning system is used to control the installation accuracy of the connectors; the composite section is divided into multiple compartments, and high-performance micro-expansion concrete is symmetrically and synchronously injected from bottom to top and from the center to both sides through the pre-set injection channels, and the compressive stress in the compartment is monitored by embedded sensors to ensure the compactness of the composite section;

[0036] S2. Construction Simulation and Alignment Control: A finite element model of the entire main beam construction process is established. Using a reverse iterative algorithm, the manufacturing alignment and installation alignment of the steel box girder at each construction stage are calculated based on the target alignment and internal force state of the completed bridge. The reverse iterative algorithm uses the least squares method to correct the error between the completed bridge state and the target state, and dynamically updates the alignment instructions of subsequent beam segments. When establishing the finite element model, BIM technology is integrated to establish a digital twin model of the entire main beam construction process.

[0037] S3. Installation of large-segment steel box girders: Three-dimensional laser scanning technology is used to obtain the actual geometric shape of the installed girder segments to assist in the adjustment of the installation alignment of subsequent girder segments. Large-segment steel box girders are transported to the bridge site by a girder transport vessel and lifted by a hydraulic lifting crane with six degrees of freedom fine adjustment function. The attitude of the girder segments is monitored in real time through GPS-RTK technology and tilt sensors. The crane automatically corrects its deviation based on the monitoring data to achieve high-precision matching of the girder segment interfaces.

[0038] S4. Closure Control: The ambient temperature and structural temperature field are monitored, and a closure joint deformation prediction model is established to determine the closure time period. The closure time period is selected during the day when the temperature change is small and the prediction model shows the lowest rate of change in the closure joint length. A bidirectional adjustable jacking device is used to actively adjust the closure joint spacing in the closure section, and the closure section is locked when the structural temperature tends to be stable. The jacking force and displacement of the bidirectional adjustable jacking device are precisely controlled according to the output command of the closure joint deformation prediction model.

[0039] S5. Tensioning and Stress Verification of Stay Cables: The tension force of stay cables during the construction stage is determined by positive iterative calculation and tensioning is carried out; stress monitoring is performed on the main beam under the maximum cantilever state and the completed bridge state, and the structural safety is verified by comparing the measured data with the finite element model results. The manufacturing line and installation line of the steel main beam are calculated by the tangent displacement method or the zero initial displacement method.

[0040] S6. Cable Saddle Anti-Slip Verification: The cable stays are tensioned using a full-scale test model to create a tension difference between the two ends. The slippage of the cable stays in the cable saddle area is measured to verify whether its anti-slip capability meets the design requirements.

[0041] S7: Analyze the sensitivity of the steel main beam's self-weight, stiffness, cable tensioning error, and temperature change parameters to the main beam's alignment, and optimize the construction monitoring scheme based on the analysis results.

[0042] During construction, sensors installed on construction equipment and key structural components collect data in real time to dynamically identify and assess the risks of large floating crane overturning and uncontrolled beam hoisting; when the assessment indicators exceed preset thresholds, the system automatically alarms.

[0043] The terms “comprising,” “including,” or any other variations thereof in this invention are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0044] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0045] In conclusion, if anyone skilled in the art, inspired by this invention, designs a similar structure and embodiment without departing from the spirit of the invention, such design should fall within the scope of protection of this invention.

Claims

1. A construction method for the main girder of a large-span, wide-width, multi-tower partially cable-stayed bridge, characterized in that: Includes the following steps: S1. Construction of the steel-concrete composite section: In the construction of the steel-concrete composite section between the zero block and the first steel box girder, a high-precision three-dimensional coordinate positioning system is used to control the installation accuracy of the connectors; the composite section is divided into multiple compartments, and high-performance micro-expansion concrete is symmetrically and synchronously injected from bottom to top and from the center to both sides through the pre-set injection channels, and the compressive stress in the compartment is monitored by embedded sensors to ensure the compactness of the composite section; S2. Construction Simulation and Alignment Control: A finite element model of the entire main beam construction process is established. A reverse iterative algorithm is adopted, with the target alignment and internal force state of the completed bridge as the benchmark, to back-calculate the manufacturing alignment and installation alignment of the steel box girder at each construction stage. The reverse iterative algorithm uses the least squares method to correct the error between the completed bridge state and the target state, and dynamically updates the alignment instructions of subsequent beam segments. S3. Installation of large-segment steel box girders: Large-segment steel box girders are transported to the bridge site by a girder transport vessel and lifted by a hydraulic lifting crane with six degrees of freedom fine adjustment function; the attitude of the girder segments is monitored in real time by GPS-RTK technology and tilt sensors, and the crane automatically corrects its deviation based on the monitoring data to achieve high-precision matching of the girder segment interfaces; S4. Closure Control: Monitor the ambient temperature and structural temperature field, establish a deformation prediction model for the closure joint to determine the closure time period; use a bidirectional adjustable jacking device to actively adjust the closure joint spacing in the closure section, and lock the closure section when the structural temperature tends to be stable. S5. Tensioning and stress verification of stay cables: The tension force of stay cables during the construction stage was determined by positive iterative calculation and tensioning was carried out; stress monitoring was carried out on the main beam under the maximum cantilever state and the completed bridge state, and the structural safety was verified by comparing the measured data with the finite element model results; S6. Cable saddle anti-slip verification: The cable stays are tensioned using a full-scale test model to create a tension difference between the two ends, and the slippage of the cable stays in the cable saddle area is measured to verify whether its anti-slip capability meets the design requirements. S7: Analyze the sensitivity of the steel main beam's self-weight, stiffness, cable tensioning error, and temperature change parameters to the main beam's alignment, and optimize the construction monitoring scheme based on the analysis results.

2. The construction method for the main beam of a large-span, wide-width, multi-tower partially cable-stayed bridge according to claim 1, characterized in that, In step S2, when establishing the finite element model, BIM technology is integrated to create a digital twin model of the entire construction process of the main beam.

3. The construction method for the main beam of a large-span, wide-width, multi-tower partially cable-stayed bridge according to claim 1, characterized in that, In step S4, the closure time period is selected during a period of day when the temperature changes less and the prediction model shows the lowest rate of change in the closure opening length.

4. The construction method for the main beam of a large-span, wide-width, multi-tower partially cable-stayed bridge according to claim 1, characterized in that, In step S4, the jacking force and displacement of the bidirectional adjustable jacking device are precisely controlled according to the output command of the closure joint deformation prediction model.

5. The construction method for the main girder of a large-span, wide-width, multi-tower partially cable-stayed bridge according to claim 1, characterized in that, In step S5, the manufacturing and installation profiles of the steel main beam are calculated using the tangential displacement method or the zero initial displacement method.

6. The construction method for the main beam of a large-span, wide-width, multi-tower partially cable-stayed bridge according to claim 1, characterized in that, Before hoisting in step S3, three-dimensional laser scanning technology is used to obtain the actual geometric shape of the installed beam segment, which is used to assist in the subsequent installation alignment adjustment of the beam segment.

7. The construction method for the main beam of a large-span, wide-width, multi-tower partially cable-stayed bridge according to claim 1, characterized in that, During construction, sensors installed on construction equipment and key structural components collect data in real time to dynamically identify and assess the risks of large floating crane overturning and uncontrolled beam hoisting; when the assessment indicators exceed preset thresholds, the system automatically alarms.