Beam-slab prefabrication pedestal and operation method

Abstract

This invention relates to the field of precast concrete structure technology, specifically to a precast beam / slab platform and its operating method. The platform includes a base, several adjustment components, several main beams, an Invar alloy panel, support components, and a sensing and processing system including a sensing module and a controller. The operating method involves the controller processing and converting real-time strain and displacement data of the beam / slab acquired by the sensing system during the precasting process into commands to drive the adjustment components to control the beam / slab's alignment. This application, through the coordinated operation of the sensing module, controller, and adjustment components, supplemented by the low thermal expansion coefficient Invar alloy panel, achieves dynamic monitoring and precise adjustment of the platform and beam / slab alignment during precasting. This improves the control accuracy of the camber during beam / slab precasting, ensures the structural safety and appearance quality of the precast beam / slab, and archives the precasting process, continuously improving production quality.

Description

Technical Field

[0001] This invention relates to the field of precast concrete structure technology, specifically to a precast beam and slab platform and its operation method. Background Technology

[0002] In highway bridge construction, precast beams such as box girders and hollow slabs are key superstructure components. To improve production efficiency, precast yards commonly employ both circular and traditional production lines for precast beam production. Both methods involve the use of precast platforms. Circular production lines typically utilize movable platforms for small beam precasting, facilitating movement between workstations within the production line. Traditional production lines, on the other hand, use fixed platforms, usually constructed from monolithic reinforced concrete or large welded steel structures. These platforms are static and rigid, designed to meet the load-bearing requirements of large beam precasting.

[0003] However, as bridge construction evolves towards larger spans, higher-strength materials, and more complex stress systems, the precision requirements for controlling geometric dimensions and camber accuracy in the precast beam process are increasing. Existing technologies, based on static and rigid designs, have limitations when dealing with varied and complex construction conditions. During beam precasting, the loads on the abutment vary due to the reinforcement, formwork, and concrete. During prestressing, the strong tension generates complex reaction forces that are transmitted to the abutment. Due to the limitations of the elastic modulus of the abutment foundation and structure, these significant load changes and reaction forces often induce localized deflection or elastic camber in the abutment. Furthermore, the large amount of heat of hydration released during concrete curing also causes thermal expansion and contraction deformation in the abutment. For rigid traditional abutments, these effects of load changes, prestress feedback, and temperature deformation are reflected in the precast beam, causing the actual camber of the precast beam to deviate from the theoretical design value, thus affecting the quality of precast beam production.

[0004] To address the challenge of controlling the camber deformation of precast beams and slabs and ensure effective alignment control during precasting, engineers often pre-set anti-cambers of a certain strength on the platform surface based on experience to counteract the upward camber deformation during prestressing. Alternatively, they may use mechanical devices such as jacks under the platform for later correction. However, these methods are relatively crude, lacking the acquisition and analysis of platform alignment and stress state, thus failing to detect beam deformation in real time and intervene proactively for correction. Therefore, there is an urgent need for a precast beam platform with information sensing and proactive adjustment capabilities to dynamically maintain the alignment of precast beams and slabs throughout the entire production cycle. Summary of the Invention

[0005] In view of the technical problems in the prior art where the precast platform adopts a static rigid structure and cannot sense and compensate for the combined effects of platform load changes, prestressing tension feedback and concrete hydration heat during the precasting process, resulting in insufficient control accuracy of the camber of the precast beam and slab and the occurrence of linear deviation, the present invention provides a precast beam and slab platform and its operation method.

[0006] The precast beam and slab platform includes: The base, which serves as the mechanical load-bearing base of the entire platform, is a reinforced concrete structure integrally cast from concrete with a strength grade of not less than C40. Several adjustment components are arranged on the base, including an electric screw motor whose bottom end is anchored to the base, and a base plate connected to the output end of the electric screw motor through a ball joint structure; Several main beams are longitudinally arranged along the base, made of standard H-beams, and the bottom surfaces of the main beams are fixedly connected to the base plate. The panel, covering the upper surface of the main beam, serves as the bottom mold for the precast beam slab and is made of Invar alloy; The support assembly, arranged on both sides of the base, is used to support the side formwork of the precast beam slab, including several hydraulic support machines hinged to the sides of the base, and a support plate connected to the output end of the hydraulic support machine; The sensing and processing system includes a controller and a sensing module integrated into the main beam and its outer periphery; the sensing module is used to acquire strain data and displacement data of the main beam; the controller is interactively connected to the adjustment component and the sensing module through an industrial-grade communication bus.

[0007] Furthermore, the Invar alloy used in the panel has a nickel content of 36±1%, and its coefficient of linear expansion in an environment ranging from -20℃ to 100℃ is no greater than 1.5×10⁻⁶. -6 / ℃, and the upper surface of the panel is polished.

[0008] Furthermore, the adjustment components are not uniformly arranged, and the spacing between each adjustment component gradually increases from the middle to the end of the base.

[0009] Furthermore, a pressure sensor is embedded inside the ball joint structure or at the connection interface between the base plate and the ball joint structure. The pressure sensor is used to monitor the vertical load borne by the adjustment component in real time and to feed back the vertical load data to the controller.

[0010] Furthermore, the sensing module includes a fiber optic strain sensor and a wire displacement gauge; the fiber optic strain sensor is embedded in the web or lower flange of the main beam to acquire stress distribution strain data of the main beam in real time, and the wire displacement gauge is set between the main beam and the base plate to acquire displacement data of the main beam relative to the horizontal plane of the base in real time, and to establish an absolute displacement coordinate system of the main beam relative to the base.

[0011] Furthermore, the operation method of the aforementioned precast beam and slab platform includes the following steps: Step S1, Initialize preset: The operator imports the preset design parameters of the precast beam into the controller, including the geometric dimensions of the beam and the design camber curve equation. The controller calculates the initial camber state that the main beam of the platform needs to achieve, converts it into the target curve equation, and calculates the initial displacement target coordinate values ​​of each adjustment component accordingly, and drives the adjustment component to adjust the main beam to the initial camber state. Step S2, benchmark verification and zeroing: The initial line shape of the panel is measured using a high-precision measuring instrument and fed back to the controller. The controller automatically completes the initial value zeroing of the sensing module and coordinate system calibration. Step S3, Reinforcement binding, formwork sealing, concrete pouring and curing: Reinforcement binding and formwork sealing are performed on the panel, followed by concrete pouring. The sensing module continuously monitors the strain data and displacement data of downward deflection caused by the reinforcement, formwork and concrete loads and transmits the data to the controller. The controller processes the data and converts the commands in real time, controlling the adjustment components to perform adjustment actions to maintain linear stability. During the curing period, the sensing module and controller rely on the low thermal expansion of the panel to continuously perform accurate data processing and command conversion, monitoring and controlling the beam and slab alignment during the curing period. Step S4, Prestressing tensioning stage: During the prestressing tensioning process, the sensing module collects the strain and displacement data of the main beam in real time, and the controller processes the data and converts commands in real time. When it is detected that the end of the platform generates a compressive reaction force due to prestressing tensioning, while the stress in the middle decreases, the adjustment component at the end is instructed to increase the support force. At the same time, the adjustment component at the mid-span is instructed to rise to track the upward arching deformation of the bottom of the beam, so as to ensure that the contact stress between the bottom of the precast beam and the panel is reasonably distributed throughout the tensioning process and maintain the beam alignment. Step S5, component demolding and controller cycle: After tensioning and anchoring are completed, the controller instructs the adjustment component to retract synchronously, so as to separate the panel from the bottom of the precast beam. Then the controller automatically resets and enters the next precast production cycle.

[0012] Furthermore, the controller incorporates a Kalman filter algorithm. This algorithm establishes a state-space model of the deformation of the main beam of the pedestal, and then weights and fuses the data containing environmental interference acquired by the sensing module with the predicted values ​​of the state-space model to filter out transient high-frequency noise generated by environmental vibration and extract data free from environmental interference.

[0013] Furthermore, in steps S3 and S4, the specific processes of data processing and instruction conversion by the controller are as follows: Sensing data preprocessing stage: The controller first analyzes and converts the raw frequency or current signals acquired by the sensing module into physical quantities, and then extracts the strain data and displacement data of the main beam of the platform through the Kalman filtering algorithm. Command conversion stage: The controller solves for the optimal extension and retraction of each regulating component by minimizing the objective function, and converts it into the optimal extension and retraction command of the output end of the electric screw motor in each regulating component; the objective function includes the deviation term between the actual linear shape and the target curve and the smoothing term of the displacement difference between adjacent regulating components.

[0014] Furthermore, during the instruction conversion stage, when the controller solves for the optimal extension command, it introduces the force feedback equation Fa=K×ΔY to determine the force feedback output of each electric screw motor; where Fa is the support force that each electric screw motor needs to output, K is the structural stiffness matrix of the base, which is an n×n matrix, calculated in advance by finite element simulation; ΔY is the displacement gap that each adjustment component needs to compensate for, ΔY=F(Xi)-Yi.

[0015] The present invention has the following beneficial effects: 1. This invention, through the deep integration of distributed active actuators and a full-time-domain sensor network, improves the mechanical support structure of traditional precast beam pedestals into a pedestal with autonomous sensing, intelligent analysis, and precise execution capabilities. This ensures that the precast beams maintain their designed alignment during the critical prestressing stage. Furthermore, by using Invar alloy panels with a low coefficient of thermal expansion on the pedestal, combined with an active thermal deformation monitoring algorithm, thermal stress cracks, which are highly susceptible to occur during the precasting of large-volume concrete, are effectively eliminated. This significantly improves the structural safety and appearance quality of the precast beams, extending the service life of bridge components.

[0016] 2. The controller described in this invention not only handles real-time adjustments but also functions as a data acquisition unit, automatically generating digital quality archives from all displacement, strain, temperature, and adjustment records of each beam slab during tensioning and curing. These archives are used for quality traceability and process optimization. This traceable production data provides accurate and objective data support for beam slab production management and quality acceptance, possessing high production and promotion value. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of a beam-slab prefabrication platform according to the present invention; Figure 2 This is a schematic diagram of some components of a beam-slab prefabrication platform according to the present invention; Figure 3 This is a schematic diagram of the overall process of the operation method of the beam and slab prefabrication platform of the present invention.

[0018] In the attached diagram: 1. Base; 2. Adjustment assembly; 21. Electric screw conveyor; 22. Base plate; 3. Main beam; 4. Panel; 5. Hydraulic support machine; 6. Support plate; 7. Side mold. Detailed Implementation

[0019] The technical solution of the present invention will now be described with reference to the accompanying drawings. However, the described embodiments are only some embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] It should be noted that in the description of this invention, the terms "upper," "lower," "inner," "outer," etc., which indicate the direction or positional relationship, are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0021] In the description of this invention, unless otherwise explicitly specified and limited, the terms "set", "install", "connect", and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to an electrical connection or a mechanical connection; they can refer to an indirect connection through an intermediate medium, or they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention in conjunction with the specific circumstances.

[0022] The accompanying drawings show various structural schematic diagrams according to embodiments disclosed in the present invention. These drawings are not drawn to scale, and some details may be enlarged or omitted for illustrative purposes.

[0023] Reference Figures 1-3 As shown, in one embodiment of the present invention, a batch of beam-slab structures for use in a highway bridge project needs to be prefabricated. A beam-slab prefabrication platform of the present invention is used, comprising the following components: Base 1, as the mechanical load-bearing base of the entire platform, is a reinforced concrete structure made of concrete with a strength grade of not less than C40, and undertakes the core function of supporting the weight of other upper components, precast beams and slabs and their formwork. Several adjustment components 2 are arranged on both sides of the longitudinal central axis of the base 1, that is, within the range of contact between the bottom mold of the precast beam and the base 1, including an electric screw motor 21 whose bottom end is anchored on the base 1 and a base plate 22 connected to the output end of the electric screw motor 21 through a ball joint structure. Several main beams 3, which serve as the main load-bearing frame, are longitudinally arranged along the base and are made of standard H-beams. The bottom surface of the main beams 3 is fixedly connected to the base plate 22. In this embodiment, welding is used to fix them in order to stably receive the vertical displacement and deformation compensation force transmitted by the adjustment component 2. Panel 4, which serves as the bottom mold for precast beam slab forming, covers the upper surface of the main beam 3 and is made of Invar alloy, which has a low coefficient of thermal expansion. Support components are arranged on both sides of the base 1 to support the side molds 7 of the precast beams and slabs during prefabrication. Specifically, the support components include several hydraulic support machines 5 hinged to the sides of the base 1, and support plates 6 connected to the hydraulic support machines 5. When working, the support plates 6 are supported by the hydraulic support machines 5 to contact the side molds 7 of the precast beams and slabs, thereby fixing and supporting the side molds 7 during the prefabrication process of the beams and slabs. The sensing and processing system includes a controller and a sensing module integrated into the main beam 3 and its outer periphery; the sensing module is used to acquire strain data and displacement data of the main beam 3; the controller can be an industrial PLC controller, which is connected to the adjustment component 2 and the sensing module through an industrial-grade communication bus to establish a data interaction link.

[0024] During beam and slab prefabrication, prestressed tension data is collected in real time by a sensing module and transmitted to the controller. The controller then processes the data fed back from the sensing module using a built-in algorithm, converting it into adjustment commands for each adjustment component 2 to adjust the alignment of the main beam 3 and panel 4. Specifically, the electric screw motor 21 in the adjustment component 2 performs precise screw extension and retraction movements according to the commands issued by the controller, transmitting the adjustment force to the base plate 22. The adjustment command is then transmitted to the main beam 3 and panel 4 via the free deflection of the ball joint structure, causing them to make corresponding deformation adjustments, thereby achieving dynamic support and fine-tuning of the prefabricated beam and slab alignment. The panel 4 uses Invar alloy material with a low coefficient of thermal expansion, which effectively reduces the thermal expansion and contraction effects caused by temperature fluctuations during the concrete curing process. This avoids interference from thermal expansion and contraction on the accuracy of the adjustment component 2's commands, allowing for more precise intervention in beam and slab deformation and preventing deformation or cracks due to inadequate or excessive adjustment of the adjustment component 2.

[0025] To ensure the stability of the pedestal during long-term use, specific structural designs, such as... Figure 1 ,2 As shown, the base 1 in this embodiment is a trapezoidal platform with a height of not less than 500mm. It is internally equipped with a double-layered, bidirectional HRB400 steel mesh, with a mesh spacing controlled at 150mm × 150mm. After concrete pouring, a precision digital level is used to precisely level the foundation surface, strictly controlling the surface flatness error within ±2mm / 10m to ensure the flatness of the surfaces after the main beam 3 and panel 4 are installed. It is then placed on the ground as a fixed platform or on a pre-set track in the prefabrication plant after being equipped with wheels.

[0026] Specifically, as the direct contact surface for the precast beam and slab forming, in this embodiment, the panel 4 is made of Invar alloy with a thickness of 20mm, a nickel content of 36±1%, and a coefficient of thermal expansion of only 1.5×10⁻⁶ in the range of -20℃ to 100℃. -6 The temperature is / ℃, far lower than that of ordinary carbon steel. During the curing process of precast beams and slabs, the heat of hydration of concrete causes a dramatic increase in the surface temperature of the pedestal. Ordinary steel panels will experience significant bulging or warping due to thermal expansion, while Invar alloy panels maintain extremely high thermal stability, significantly reducing the impact of thermal expansion and contraction on the deformation of panel 4. This ensures that the bottom mold line does not become inaccurate due to temperature field changes, preventing the adjustment component 2 from failing. Furthermore, the surface of panel 4 undergoes precision grinding and polishing to reduce frictional resistance during demolding of the precast beams and slabs.

[0027] To ensure the precision of the adjustment component 2 in executing controller commands under complex prefabrication conditions, in this embodiment, the adjustment component 2 is securely connected to the base 1 via high-strength pre-embedded bolt groups. Each bolt group consists of four M24 grade 8.8 high-strength bolts with an anchoring depth of not less than 350mm, ensuring that the adjustment component 2 will not experience slight displacement relative to the base 1 during adjustment, thus preventing any impact on the adjustment result. Furthermore, to enhance the control effect of the adjustment component 2 on the main beam 3 and the panel 4, such as... Figure 2 As shown, the adjustment components 2 are arranged non-uniformly on the base 1. Specifically, the spacing between each adjustment component 2 increases from small to large in the direction extending from the middle to the ends of the base 1, to adapt to the stress characteristics and deformation requirements of different areas. In this embodiment, the minimum spacing between each adjustment component 2 near the middle of the base 1 is 0.5m, and the maximum spacing at the ends of the base 1 is 1.5m. This is because in the area near the middle, the load on the beam and slab is relatively concentrated and the stress distribution is more complex, the arching deformation is more obvious, and the deformation deflection is greater. The arrangement of the adjustment components 2 is more dense so that the deformation of the main beam 3 and the panel 4 can be adjusted more precisely.

[0028] In order to monitor the actual vertical load borne by each adjustment component 2 in real time, a pressure sensor, such as a high-precision strain gauge pressure transmitter, is embedded inside the ball joint structure or at the connection interface between the base plate 22 and the ball joint structure. Through the force feedback signal collected by the sensor, the controller can determine whether there is a void or overload at the support part of the adjustment component 2 corresponding to the precast beam slab. This ensures that the adjustment of the beam slab by the adjustment component 2 during the precasting process can be accurately monitored and fed back in the form of data, so as to intervene in a timely manner and ensure that the support of the pedestal on the precast beam slab is always effective.

[0029] Specifically, the sensing module includes a fiber optic strain sensor and a wire-type displacement gauge. The fiber optic strain sensor is embedded at a critical stress section of the main beam 3, such as near the bottom of the main beam 3. The wire-type displacement gauge is positioned between the main beam 3 and the base plate 22. In this embodiment, the fiber optic strain sensor uses a narrowband laser with a wavelength of 1550nm as the detection light source. Utilizing the Bragg reflection principle, the microscopic strain of the main beam 3 is calculated by demodulating the drift of the reflected wavelength. The wire-type displacement gauge has a resolution of 0.01mm and a range of ±10mm. It is used to acquire the displacement data of each adjustment component on the main beam of the pedestal relative to the horizontal plane of the base 1 in real time, and to establish an absolute displacement coordinate system of the main beam 3 relative to the base 1, with the center point of the base 1 as the origin, the longitudinal direction as the Y-axis, and the transverse direction as the X-axis.

[0030] In the specific implementation scenario of this embodiment, such as Figure 3 As shown, the specific operation process of the beam and slab precast platform of the present invention is as follows: Step S1, initialize presets; Before the production of beams and slabs, the operator imports the design parameters of the batch of precast beams and slabs into the controller, including the geometric dimensions of the beams and slabs and the design camber curve equation. The controller calculates the initial camber state that the main beam of the platform needs to achieve, converts it into the target curve equation, and calculates the initial displacement target coordinate value of each adjustment component 2 accordingly. The controller then drives the execution unit to adjust the main beam 3 to the initial camber state. Step S2, benchmark verification and zeroing; After the various parts of the pedestal are adjusted, the initial alignment of the pedestal panel 4 surface is measured using a high-precision total station. The measured data is then transmitted synchronously to the controller via a wireless interface. The controller automatically compares the measured values ​​with the command values ​​and automatically calibrates and compensates the initial values ​​and coordinate system of each sensor module to ensure the actual initial arching state of the corresponding pedestal.

[0031] Step S3: Rebar tying, formwork sealing, concrete pouring and curing; The steel reinforcement binding and formwork sealing processes are carried out on the panel 4, followed by concrete pouring. The sensing module continuously monitors the strain data and displacement data of downward deflection caused by the steel reinforcement, formwork and concrete load, and transmits the data to the controller. The controller processes the data in real time and controls the adjustment component 2 to perform adjustment actions to maintain the stability of the beam shape. During the curing period, the sensing module and controller rely on the low thermal expansion of the panel 4 to continuously perform accurate data processing and command transmission, fine-tune the support force of each node, and monitor and control the beam and slab shape during the curing period.

[0032] Step S4, active intervention control during the prestressing tensioning stage; After the concrete is poured, when the beam is tensioned, the shrinkage of the prestressing tendons will cause the beam to arch upwards. At this time, the central area of ​​the beam will gradually detach from the abutment, while the ends of the beam will exert intense concentrated pressure on the base. Meanwhile, the sensing module collects the strain and displacement data of the main beam 3 in real time, and the controller controls each adjustment component 2 to actively load, tracking the upward arching deformation at the bottom of the beam and maintaining the beam's alignment. Specifically, when the precast beam end is detected to generate a compressive reaction force on the base due to prestressing tension, the end adjustment component 2 is controlled to increase the support force, thereby increasing the support stiffness of that part and offsetting the deformation effect of the compressive reaction force on the base. At the same time, the adjustment component 2 at the mid-span is instructed to rise to track the upward arching deformation of the beam bottom, ensuring a reasonable distribution of contact stress between the bottom of the precast beam and the panel 4 throughout the tensioning process, and maintaining the beam shape. This active intervention control ensures that the contact state between the beam bottom and the platform panel 4 is within a controlled range throughout the tensioning process, ensuring a reasonable distribution of contact stress between the bottom of the precast beam and the panel 4 throughout the tensioning process. This avoids the beam from undergoing additional linear changes due to the tension force affecting the platform during the tensioning process, which would lead to an uneven transmission of the support force of the platform to the beam, resulting in uncontrolled changes in the beam shape.

[0033] Step S5: Component demolding and controller loop; Once the beam strength meets the standard and tensioning and anchoring are completed, the controller instructs all adjusting components 2 to simultaneously retract 10mm-20mm, using the precise return of the push rods to achieve smooth separation of the components from the bottom formwork. After the beam transfer is completed, the controller automatically resets and adjusts the alignment of the main beam 3 according to the parameter instructions for the next beam, entering the next precast production cycle.

[0034] Specifically, during the data and command conversion process, the controller first analyzes and converts the raw frequency or current signals acquired by the sensing modules into physical quantities during the preprocessing stage. Because the prefabrication yard contains high-frequency vibration sources such as concrete vibration and hoisting equipment operation, the raw signals often contain a large amount of noise. In this embodiment, the controller incorporates a Kalman filter algorithm. This algorithm establishes a state-space model of the deformation of the main beam of the pedestal, and then weights and fuses the data acquired by the sensing modules containing environmental interference with the predicted values ​​of the state-space model. This filters out transient high-frequency noise generated by environmental vibration, thereby obtaining the most accurate strain and displacement data reflecting the prefabrication process of the main beam 3.

[0035] The controller automatically calculates the theoretical height that the platform needs to reach during prefabrication based on the beam camber parameters preset in step S1, such as the geometric dimensions of the beam and the designed camber curve equation, and converts it into a target curve equation. During the formal data processing and instruction conversion stage, the real-time position data fed back by the sensing module during prefabrication is compared with the target curve equation corresponding to the theoretical height. If the deviation exceeds a set threshold (set to 0.5mm in this embodiment), an adjustment instruction for the corresponding adjustment component 2 is output. Specifically: First, set the platform to have n adjustment components 2 distributed longitudinally. The extension and retraction of the output end of the i-th (i=1, 2...n) adjustment component 2 is Si. The measured coordinates of each adjustment component 2 are obtained by the sensing module as (Xi, Yi). The target curve equation is F(Xi), which represents the theoretical height of the position corresponding to the i-th adjustment component 2 calculated according to the target curve equation.

[0036] Next, construct the objective function: ; where ΔY i (S) i ) is the transfer function of the displacement of the i-th adjustment component 2 and the linear change of the main beam 3. It represents the actual height that the main beam 3 can rise or fall after the i-th adjustment component 2 extends or retracts by Si. It can be obtained in advance by using finite element influence line analysis through the finite element stiffness model of the main beam 3. λ is the smoothing factor, which is usually between 0.1 and 0.5. It is calibrated by experiments and represents the weight of the adjustment component 2 in conforming to the target curve or smooth adjustment during the adjustment process. It is a fixed parameter. In this embodiment, it is set to 0.1. The larger λ is, the more priority will be given to smooth adjustment during the adjustment process, reducing the sense of shock of sudden adjustment. The smaller λ is, the more priority will be given to adjustment in the way of conforming to the curve.

[0037] The objective function includes a term for the deviation between the actual alignment and the target curve, and a smoothing term for the displacement difference between adjacent adjustment components. Specifically, the first term minimizes the deviation between the actual alignment and the target curve, ensuring that the actual height of panel 4, driven by the main beam 3, is as close as possible to the theoretical height. The second term limits the displacement difference between adjacent push rods, preventing excessive local bending stress in panel 4 during adjustment. J is the total execution cost coefficient. The smaller the J value, the closer the alignment of panel 4 after adjustment by adjustment component 2 conforms to the target curve equation, and the smoother the adjustment process. Based on this objective function, the controller calculates the extension / retraction amount Si that minimizes J, thereby obtaining the optimal extension / retraction command at the output of the electric screw motor 21 in each adjustment component 2.

[0038] Furthermore, when the controller solves for the optimal extension / retraction command, it also introduces the inverse operation of the structural stiffness matrix K of the base. The force feedback output of each electric screw motor 21 is determined by solving the force feedback equation Fa=K×ΔY. Here, F is the support force that each adjustment component 2 needs to output, K is the structural stiffness matrix of the base, which is an n×n matrix (n is the same as above, representing the number of adjustment components 2), and is calculated in advance by static analysis through finite element simulation based on the material, structure, and shape of the base. ΔY is the displacement gap that each adjustment component 2 needs to compensate for, i.e., the target curve equation F(Xi)-measured coordinate Yi, corresponding to the total displacement that the adjustment component 2 needs to adjust. Specifically, the force feedback equation transforms the displacement deviation ΔY required by the adjustment component 2 into the actual required adjustment force Fa through the structural stiffness matrix K, and then drives the servo push rod to output force. This is beneficial for accurately distributing the pushing force of each push rod according to the hardness characteristics of the base. Under the optimal extension and retraction command of each adjustment component 2 obtained based on the objective function J, the adjustment force of the adjustment component 2 is determined through the force feedback equation. The combination of the two further ensures the accurate execution of the total displacement that the adjustment component 2 needs to adjust.

[0039] This invention, through the integration of a base 1, an adjustment component 2, and a sensing and processing system, realizes a precast beam and slab platform capable of real-time sensing and dynamic adjustment. This solves the problem of low linear control accuracy in traditional platforms, thereby significantly improving the structural safety and appearance quality of precast beams and slabs, and extending the service life of bridge components. Furthermore, throughout the precasting process, the controller automatically generates complete digital records, including displacement, strain, temperature, and adjustment parameters of the adjustment component 2 at each time point. This data not only provides a reliable basis for subsequent quality traceability but also enables continuous optimization of the precasting process through big data analysis, improving production efficiency and product quality.

[0040] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A precast beam and slab platform, characterized in that, include: The base, which serves as the mechanical load-bearing base of the entire platform, is a reinforced concrete structure integrally cast from concrete with a strength grade of not less than C40. Several adjustment components are arranged on the base, including an electric screw motor whose bottom end is anchored to the base, and a base plate connected to the output end of the electric screw motor through a ball joint structure; Several main beams are longitudinally arranged along the base, made of standard H-beams, and the bottom surfaces of the main beams are fixedly connected to the base plate. The panel, covering the upper surface of the main beam, serves as the bottom mold for the precast beam slab and is made of Invar alloy; The support assembly, arranged on both sides of the base, is used to support the side formwork of the precast beam slab, including several hydraulic support machines hinged to the sides of the base, and a support plate connected to the output end of the hydraulic support machine; The sensing and processing system includes a controller and a sensing module integrated into the main beam and its outer periphery; the sensing module is used to acquire strain data and displacement data of the main beam; the controller is interactively connected to the adjustment component and the sensing module through an industrial-grade communication bus.

2. The beam and slab prefabrication platform according to claim 1, characterized in that, The Invar alloy used in the panel has a nickel content of 36±1%, and its coefficient of linear expansion in an environment ranging from -20℃ to 100℃ is no greater than 1.5×10⁻⁶. -6 / ℃, and the upper surface of the panel is polished.

3. The beam and slab prefabrication platform according to claim 1, characterized in that, The adjustment components are not uniformly arranged, and the spacing between each adjustment component increases from the middle to the end of the base.

4. A precast beam and slab platform according to claim 1, characterized in that, A pressure sensor is embedded inside the ball joint structure or at the connection interface between the base plate and the ball joint structure. The pressure sensor is used to monitor the vertical load borne by the adjustment component in real time and to feed back the vertical load data to the controller.

5. A precast beam and slab support according to claim 1, characterized in that, The sensing module includes a fiber optic strain sensor and a wire displacement gauge. The fiber optic strain sensor is embedded in the web or lower flange of the main beam to acquire stress distribution strain data of the main beam in real time. The wire displacement gauge is set between the main beam and the base plate to acquire displacement data of the main beam relative to the horizontal plane of the base in real time and to establish an absolute displacement coordinate system of the main beam relative to the base.

6. The operating method of a beam and slab precast platform according to any one of claims 1-5, characterized in that, Includes the following steps: Step S1, Initialize preset: The operator imports the preset design parameters of the precast beam into the controller, including the geometric dimensions of the beam and the design camber curve equation. The controller calculates the initial camber state that the main beam of the platform needs to achieve, converts it into the target curve equation, and calculates the initial displacement target coordinate values ​​of each adjustment component accordingly, and drives the adjustment component to adjust the main beam to the initial camber state. Step S2, benchmark verification and zeroing: The initial line shape of the panel is measured using a high-precision measuring instrument and fed back to the controller. The controller automatically completes the initial value zeroing of the sensing module and coordinate system calibration. Step S3, Reinforcement binding, formwork sealing, concrete pouring and curing: Reinforcement binding and formwork sealing are performed on the panel, followed by concrete pouring. The sensing module continuously monitors the strain data and displacement data of downward deflection caused by the reinforcement, formwork and concrete loads and transmits the data to the controller. The controller processes the data and converts the commands in real time, controlling the adjustment components to perform adjustment actions to maintain linear stability. During the curing period, the sensing module and controller rely on the low thermal expansion of the panel to continuously perform accurate data processing and command conversion, monitoring and controlling the beam and slab alignment during the curing period. Step S4, Prestressing tensioning stage: During the prestressing tensioning process, the sensing module collects the strain and displacement data of the main beam in real time, and the controller processes the data and converts commands in real time. When it is detected that the end of the platform generates a compressive reaction force due to prestressing tensioning, while the stress in the middle decreases, the adjustment component at the end is instructed to increase the support force. At the same time, the adjustment component at the mid-span is instructed to rise to track the upward arching deformation of the bottom of the beam, so as to ensure that the contact stress between the bottom of the precast beam and the panel is reasonably distributed throughout the tensioning process and maintain the beam alignment. Step S5, component demolding and controller cycle: After tensioning and anchoring are completed, the controller instructs the adjustment component to retract synchronously, so as to separate the panel from the bottom of the precast beam. Then the controller automatically resets and enters the next precast production cycle.

7. The operation method of a beam and slab precast platform according to claim 6, characterized in that, The controller incorporates a Kalman filter algorithm. This algorithm establishes a state-space model of the deformation of the main beam of the pedestal, and then weights and fuses the data containing environmental interference acquired by the sensing module with the predicted values ​​of the state-space model to filter out transient high-frequency noise generated by environmental vibration and extract data that has been freed from environmental interference.

8. The operation method of a beam and slab precast platform according to claim 7, characterized in that, In steps S3 and S4, the specific processes of data processing and instruction conversion by the controller are as follows: Sensing data preprocessing stage: The controller first analyzes and converts the raw frequency or current signals acquired by the sensing module into physical quantities, and then extracts the strain data and displacement data of the main beam of the platform through the Kalman filtering algorithm. Command conversion stage: The controller solves for the optimal extension and retraction of each regulating component by minimizing the objective function, and converts it into the optimal extension and retraction command of the output end of the electric screw motor in each regulating component; the objective function includes the deviation term between the actual linear shape and the target curve and the smoothing term of the displacement difference between adjacent regulating components.

9. The operation method of a beam and slab precast platform according to claim 8, characterized in that, During the instruction conversion stage, when the controller solves for the optimal extension command, it introduces the force feedback equation Fa=K×ΔY to determine the force feedback output of each electric screw motor. Here, Fa is the support force that each electric screw motor needs to output, K is the structural stiffness matrix of the base, which is an n×n matrix and is calculated in advance by finite element simulation; ΔY is the displacement gap that each adjustment component needs to compensate for, ΔY=F(Xi)-Yi.

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