Synchronous tensioning process for bridge prestressed carbon plate

Abstract

The invention discloses a synchronous tensioning process for a bridge prestressed carbon plate. The synchronous tensioning technology for the prestressed carbon plates comprises the steps that firstly, the number of needed prestressed carbon plate anchorage devices is calculated according to the tensioning stress requirement of a bridge to be reinforced, then the installation positions of the prestressed carbon plate anchorage devices are determined, and the prestressed carbon plate anchorage devices and a control system are connected with a high-pressure oil cylinder, an electromagnetic valve set and a servo hydraulic pump station; secondly, synchronous tensioning system tensioning parameter setting, manual control positioning and carbon plate pre-tightening are carried out, and a system main interface pre-tensioning value setting frame is controlled to carry out pre-tensioning step operation; and finally, automatic tensioning operation is conducted, after all stages are executed, adhesive glue is filled for repairing, and a tensioning system is dismantled. According to the method, the bridge is reinforced through the synchronous tensioning technology of the multiple prestressed carbon plates, the difficulty of the prestressed carbon plates in bridge construction is overcome, and the application of the prestressed carbon plate reinforcing technology under the complex working condition is expanded.

Description

Technical Field

[0001] The invention belongs to the technical field of bridge reinforcement, and in particular relates to a synchronous tensioning process for prestressed carbon plates of bridges. Background Art

[0002] Prestressed carbon plate reinforcement technology is an emerging reinforcement technology in recent years. By applying prestress to the carbon fiber plate, its high strength can be fully utilized. Compared with non-prestressed carbon fiber reinforcement, it can effectively improve the strength and stiffness of the reinforced structure. At present, prestressed carbon plate reinforcement technology is widely used in bridge reinforcement. For bridges, a higher tension value is required for reinforcement design. The effect of simply increasing the tension value from the perspective of increasing a single prestressed carbon fiber plate is limited, and this method will significantly increase the risk of carbon fiber plate unanchoring, posing a great threat to safety. At present, the method of increasing the overall tension value is mainly to increase the number of carbon fiber plates to build a tensioning system. However, the tensioning method of multiple carbon plates in the existing technology has a large demand for tensioning area, and the tension stress distribution between each carbon plate is difficult to balance, which is very easy to cause carbon plate wire collapse and damage. Summary of the invention

[0003] In response to the problems existing in the above-mentioned background technology, the present invention provides a synchronous tensioning process of prestressed carbon plates for bridges, which utilizes the synchronous tensioning process of multiple prestressed carbon plates to reinforce bridges, overcomes the difficulties of prestressed carbon plates in bridge construction, and expands the application of prestressed carbon plate reinforcement technology under complex working conditions.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] A synchronous tensioning process for a bridge prestressed carbon plate comprises the following steps:

[0006] (1) Determination of the number of prestressed carbon plate anchors: Design a reinforcement plan based on the actual situation of the bridge to be reinforced, adopt a prestressed carbon plate synchronous tensioning system for reinforcement, and calculate the number of prestressed carbon plate anchors N required in the synchronous tensioning system according to the tensioning stress demand of the bridge to be reinforced, where N ≥ 2;

[0007] Design of the reinforcement scheme in step (1): Based on the inspection of the bridge structure that has been in service for many years, combined with the actual damage of the bridge itself, including cracks, damage, prestress loss, etc., the bridge grade is assessed according to the bridge inspection results, and then the design verification is carried out, and the bridge reinforcement design scheme is determined based on the verification results;

[0008] (2) Positioning and connection of prestressed carbon plate anchors: According to the construction requirements, the surface of the bridge to be reinforced is laid out according to the design drawings, and the positions of the carbon fiber plates and the fixed and tensioned anchors in the prestressed carbon plate anchors are determined. Every two prestressed carbon plate anchors are laid at equal intervals, and the base surface treatment, drilling and reinforcing bars, and carbon fiber plate cutting are completed. The two ends of the carbon fiber plates are respectively connected to the corresponding fixed end anchor anchor positions, and connected to the tensioned end anchor through high-strength tensioning screws;

[0009] The setting out in step (2) is to set out and locate the position according to the position specified in the design drawing, accurately drill the hole position for anchor installation, and use a steel ruler to check and calibrate the position after the anchor installation is completed;

[0010] The carbon fiber plate in step (2) is generally 20 to 300 mm wide and 1.2 to 5 mm thick;

[0011] (3) Connection of prestressed carbon plate synchronous tensioning system: Install a high-pressure oil cylinder at the tensioning end of each prestressed carbon plate anchor, and ensure that the high-pressure oil cylinder is consistent with the center of the carbon fiber plate. Each high-pressure oil cylinder is connected to the oil circuit connector on the solenoid valve group through a pipeline, and the solenoid valve group is connected to the servo hydraulic pump station to provide a power source for the high-pressure oil cylinder; the control system is used to establish signal connections with the solenoid valve group, the servo hydraulic pump station and the high-pressure oil cylinder through the solenoid valve group signal connector, the hydraulic pump station signal connector and the displacement signal connector;

[0012] A high-precision displacement sensor is installed on the side wall of the high-pressure oil cylinder in step (3) to monitor the tensioning force and the elongation of the prestressed carbon plate in real time. The data of the sensor will be transmitted to the control system in real time for controlling and analyzing the tensioning process;

[0013] The control system in step (3) uses an advanced programmable logic controller (PLC) as the core control unit, which has high reliability and stability, and is equipped with a touch screen with a user-friendly interface, which is convenient for operators to set tensioning parameters, monitor the tensioning process and view historical data; the control system has both automatic control and manual control modes to meet the needs of different working conditions;

[0014] The solenoid valve group in step (3) is provided with N oil circuit connectors, which are connected to the oil cylinders one by one through pipelines, and each oil circuit is independently controlled by a control valve to realize the operation of each hydraulic cylinder;

[0015] The servo hydraulic pump station in step (3) is a high-performance hydraulic pump station, which provides a stable power source for the high-pressure oil cylinder and adopts advanced hydraulic control technology to ensure the stable pressure and rapid response of the hydraulic system; the circuit of the servo hydraulic pump station is provided with an oil cylinder reflux separation valve;

[0016] (4) Synchronous tensioning system tensioning parameter setting: Turn on the system and enter the parameter setting page. Input the response parameters in combination with the technical parameters required by the design drawings. The system automatically calculates the graded tensioning stress and other parameters based on the input parameters. After the input is completed, the technical indicators are reviewed and calibrated.

[0017] The technical parameters in step (4) include the designed tensile stress, the cross-sectional area of ​​the carbon plate, the elastic modulus of the carbon plate, etc., and the response parameters include the designed tensile stress, the theoretical elongation, the length of the carbon plate, the elastic modulus of the carbon plate, the step-by-step stage holding time, the name of the bridge, the construction location, etc.;

[0018] (5) Manual control positioning and carbon plate pre-tightening: Install the anchor plate and ensure that the center lines of the fixed end anchor plate and the tension end anchor plate are consistent. Then connect the fixed end anchor and the tension end anchor to the anchor plate respectively. Finally, switch the equipment to the pre-tightening program or manual state, and perform the pre-tightening step in the pre-tightening value setting box. The pre-tightening stress is set to 1-5KN. The synchronous tensioning system tightens the carbon fiber plate to the initial pre-tightening state, so that the state of the pulled carbon fiber plate is parallel to the bottom of the bridge.

[0019] The anchor plate is fixed to the beam surface to be reinforced by high-strength chemical bolts;

[0020] (6) Pre-tensioning: First, select the tensioning mode on the main interface of the control system. The tensioning mode options include manual and automatic modes. In the automatic tensioning mode, press the start button and the system will start tensioning in graded sections according to the set parameters, with graded stages 1-20. Stress is applied to the components along the tensile direction of the structure to start pre-operation. After the system tension reaches the single-stage set value, the system automatically starts to hold the load. After the holding time is reached, the next stage of tensioning will be automatically started. After the designed tensioning stress is completed, the system automatically stops and performs safety holding. After the holding time is completed, the pre-tensioning step is completed.

[0021] Specifically, firstly, a solenoid valve group is used to simultaneously apply a stress of 10% of the total tensile force to all carbon fiber plates, so that the carbon fiber plates are stretched and tightened, and then enter the load holding stage. During the load holding process, the tensile stress and elongation data on the display screen are observed to be normal, and the bridge prestressed anchors, carbon plates, anchor bolts, etc. are detected to be normal; then, pre-tension is applied to each carbon fiber plate in stages by 20%, 30%, 40% until 100%, and the load is held for 1-5 minutes between each level, and the deviation between the measured value and the calculated value is compared; when the pre-tension is applied to 100%, the final tensile elongation value of the carbon fiber plate is reviewed and held for 5 minutes. After the pre-tensioning is completed, the pre-tensioning data is recorded and saved, and then the pressure is relieved and the high-pressure cylinder is retracted; the pressure relief operation first switches the system to manual mode, and long presses the retract key on the control system touch screen, and the system starts to slowly relieve pressure; the cylinder retract knob on the system panel can also be rotated in manual mode, and the cylinder can also be automatically retracted.

[0022] After the pre-tensioning is completed, check again whether the anchor carbon plate is intact after being stressed. After confirming that it is intact, proceed to the next step.

[0023] (7) Applying carbon plate glue: Each carbon fiber plate is bonded to the reinforced structural surface through carbon fiber plate glue to form bonding prestress, so that the new and old components are stressed together, effectively eliminating the stress lag problem of passive reinforcement and achieving the purpose of active structural reinforcement;

[0024] (8) Formal tensioning: Select the corresponding oil cylinder on the main interface of the control system and set the parameters to perform automatic tensioning operations consistent with the pre-tensioning process. The synchronous tensioning system is divided into M-stage tensioning and sets 1%-100% tensioning data. The tensioning that needs to be divided into M stages and the tension required for each stage are pre-entered in the process parameter interface; after selecting the automatic mode, the status display is consistent with the selected mode, press the start button, and use the control system to start the synchronous tensioning operation of each carbon fiber plate, and monitor the displacement and stretching movement in real time to ensure that the high-pressure oil cylinder has sufficient tensioning space; perform tensioning operations step by step according to the process requirements until the last stage is completed;

[0025] After each stage of tensioning is completed, the condition of the carbon fiber plate should be observed for at least 1-5 minutes. After reaching 100% tension stress level, the load should be held for at least 5 minutes for observation.

[0026] During the automatic tensioning operation, tensioning is performed step by step with reference to tensioning parameters, and the tensioning stages can be divided into 1-100 stages;

[0027] The tension control stress of the system should be between 0.4 and 0.7 times the design value of the carbon fiber plate material (960-1680MPa), and should not be greater than 0.7 times;

[0028] (9) After all stages are completed, fill with adhesive to repair and maintain aesthetics, and after maintaining the designed time, remove the tensioning system.

[0029] Furthermore, each of the high-pressure oil cylinders can work independently or in coordination.

[0030] Furthermore, after all stages of the tensioning work are completed, adhesive is filled for repair to maintain aesthetics and neatness, and after maintaining the designed time, the anchor is removed.

[0031] Furthermore, the synchronous tensioning system has an overload protection function. When the tensioning force exceeds a certain proportion of the set value, the tensioning is automatically stopped and an alarm is sounded.

[0032] Furthermore, the control system monitors the oil temperature, oil pressure, etc. to ensure safe operation of the system.

[0033] Furthermore, the on-site measured strength grade of the reinforced bridge concrete structural member shall not be lower than C25, and the positive tensile bond strength of the concrete surface shall not be lower than 2.0 MPa.

[0034] Furthermore, during the tensioning of the carbon fiber plate in step (6), the change in the deflection of the beam body is observed. If the deflection change is abnormal, the tensioning should be stopped and the cause should be checked.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) When the tensioning process described in the present invention is used for construction, the high-pressure oil cylinder of any oil circuit is an independent working unit, and the control system operation panel can accurately display the tensioning working status of each oil circuit. If any oil circuit has an abnormality during the synchronous tensioning construction, it will not affect the tensioning of other carbon plates.

[0037] (2) The present invention considers that the direction of the tensioning stress is basically coaxial with the force direction of the carbon fiber plate, so that during the carbon plate tensioning construction, the carbon plate only bears tensile stress, which can greatly improve the success rate of the carbon plate tensioning process, effectively avoid the breakage rate of the carbon plate, and truly give full play to the high-strength performance of the carbon fiber plate, achieve the purpose of reinforcement, and effectively improve the safety of prestressed tensioning construction.

[0038] (3) The tensioning process of the present invention can be applied to various bridge structures such as composite box girders, cast-in-place box girders, and plate girders; it can also be used to reinforce and strengthen the structures of concrete components and steel structure components in the construction field. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the synchronous tensioning system of the prestressed carbon plates for bridges according to the present invention.

[0040] Figure 2 This is the control system interface diagram.

[0041] Figure 1 The markings are: 1. Control main box; 11. Hydraulic pump station signal connector; 12. Solenoid valve group signal connector; 13. Displacement signal connector; 2. Solenoid valve group; 21. Pressure sensor; 22. Valve group signal connector; 3. Servo hydraulic pump station; 4. Cylinder reflux separation valve; 5. Displacement sensor; 6. High-pressure cylinder; 7. Tensioning end anchor; 8. Carbon fiber plate; 9. Fixed end anchor. DETAILED DESCRIPTION

[0042] The present invention is further described below in conjunction with the accompanying drawings and the following embodiments. The following embodiments are only used to illustrate the present invention but not to limit the present invention.

[0043] A synchronous tensioning process for a bridge prestressed carbon plate comprises the following steps:

[0044] (1) Determination of the number of prestressed carbon plate anchors: Design a reinforcement plan based on the actual situation of the bridge to be reinforced, adopt a prestressed carbon plate synchronous tensioning system for reinforcement, and calculate the number of prestressed carbon plate anchors N required in the synchronous tensioning system according to the tensioning stress demand of the bridge to be reinforced, where N ≥ 2;

[0045] Design of the reinforcement scheme in step (1): Based on the inspection of the bridge structure that has been in service for many years, combined with the actual damage of the bridge itself, including cracks, damage, prestress loss, etc., the bridge grade is assessed according to the bridge inspection results, and then the design verification is carried out, and the bridge reinforcement design scheme is determined based on the verification results;

[0046] (2) Positioning and connection of prestressed carbon plate anchors: According to the construction requirements, the surface of the bridge to be reinforced is laid out according to the design drawings, and the positions of the carbon fiber plates and the fixed and tensioned anchors in the prestressed carbon plate anchors are determined. Every two prestressed carbon plate anchors are laid at equal intervals, and the base surface treatment, drilling and reinforcing bars, and carbon fiber plate cutting are completed. The two ends of the carbon fiber plates are respectively connected to the corresponding fixed end anchor anchor positions, and connected to the tensioned end anchor through high-strength tensioning screws;

[0047] The setting out in step (2) is to set out and locate the position according to the position specified in the design drawing, accurately drill the hole position for anchor installation, and use a steel ruler to check and calibrate the position after the anchor installation is completed;

[0048] The carbon fiber plate in step (2) is generally 20 to 300 mm wide and 1.2 to 5 mm thick;

[0049] (3) Connection of prestressed carbon plate synchronous tensioning system: Install a high-pressure oil cylinder at the tensioning end of each prestressed carbon plate anchor, and ensure that the high-pressure oil cylinder is consistent with the center of the carbon fiber plate. Each high-pressure oil cylinder is connected to the oil circuit connector on the solenoid valve group through a pipeline, and the solenoid valve group is connected to the servo hydraulic pump station to provide a power source for the high-pressure oil cylinder; the control system is used to establish signal connections with the solenoid valve group, the servo hydraulic pump station and the high-pressure oil cylinder through the solenoid valve group signal connector, the hydraulic pump station signal connector and the displacement signal connector;

[0050] A high-precision displacement sensor is installed on the side wall of the high-pressure oil cylinder in step (3) to monitor the tensioning force and the elongation of the prestressed carbon plate in real time. The data of the sensor will be transmitted to the control system in real time for controlling and analyzing the tensioning process;

[0051] The control system in step (3) uses an advanced programmable logic controller (PLC) as the core control unit, which has high reliability and stability, and is equipped with a touch screen with a user-friendly interface, which is convenient for operators to set tensioning parameters, monitor the tensioning process and view historical data; the control system has both automatic control and manual control modes to meet the needs of different working conditions;

[0052] The solenoid valve group in step (3) is provided with N oil circuit connectors, which are connected to the oil cylinders one by one through pipelines, and each oil circuit is independently controlled by a control valve to realize the operation of each hydraulic cylinder;

[0053] The servo hydraulic pump station in step (3) is a high-performance hydraulic pump station, which provides a stable power source for the high-pressure oil cylinder and adopts advanced hydraulic control technology to ensure the stable pressure and rapid response of the hydraulic system; the circuit of the servo hydraulic pump station is provided with an oil cylinder reflux separation valve;

[0054] (4) Synchronous tensioning system tensioning parameter setting: Turn on the system and enter the parameter setting page. Input the response parameters in combination with the technical parameters required by the design drawings. The system automatically calculates the graded tensioning stress and other parameters based on the input parameters. After the input is completed, the technical indicators are reviewed and calibrated.

[0055] The technical parameters in step (4) include the designed tensile stress, the cross-sectional area of ​​the carbon plate, the elastic modulus of the carbon plate, etc., and the response parameters include the designed tensile stress, the theoretical elongation, the length of the carbon plate, the elastic modulus of the carbon plate, the step-by-step stage holding time, the name of the bridge, the construction location, etc.;

[0056] (5) Manual control positioning and carbon plate pre-tightening: Install the anchor plate and ensure that the center lines of the fixed end anchor plate and the tension end anchor plate are consistent. Then connect the fixed end anchor and the tension end anchor to the anchor plate respectively. Finally, switch the equipment to the pre-tightening program or manual state, and perform the pre-tightening step in the pre-tightening value setting box. The pre-tightening stress is set to 1-5KN. The synchronous tensioning system tightens the carbon fiber plate to the initial pre-tightening state, so that the state of the pulled carbon fiber plate is parallel to the bottom of the bridge.

[0057] The anchor plate is fixed to the beam surface to be reinforced by high-strength chemical bolts;

[0058] (6) Pre-tensioning: First, select the tensioning mode on the main interface of the control system. The tensioning mode options include manual and automatic modes. In the automatic tensioning mode, press the start button and the system will start tensioning in graded sections according to the set parameters, with graded stages 1-20. Stress is applied to the components along the tensile direction of the structure to start pre-operation. After the system tension reaches the single-stage set value, the system automatically starts to hold the load. After the holding time is reached, the next stage of tensioning will be automatically started. After the designed tensioning stress is completed, the system automatically stops and performs safety holding. After the holding time is completed, the pre-tensioning step is completed.

[0059] Specifically, firstly, a solenoid valve group is used to simultaneously apply a stress of 10% of the total tensile force to all carbon fiber plates, so that the carbon fiber plates are stretched and tightened, and then enter the load holding stage. During the load holding process, the tensile stress and elongation data on the display screen are observed to be normal, and the bridge prestressed anchors, carbon plates, anchor bolts, etc. are detected to be normal; then, pre-tension is applied to each carbon fiber plate in stages by 20%, 30%, 40% until 100%, and the load is held for 1-5 minutes between each level, and the deviation between the measured value and the calculated value is compared; when the pre-tension is applied to 100%, the final tensile elongation value of the carbon fiber plate is reviewed and held for 5 minutes. After the pre-tensioning is completed, the pre-tensioning data is recorded and saved, and then the pressure is relieved and the high-pressure cylinder is retracted; the pressure relief operation first switches the system to manual mode, and long presses the retract key on the control system touch screen, and the system starts to slowly relieve pressure; the cylinder retract knob on the system panel can also be rotated in manual mode, and the cylinder can also be automatically retracted.

[0060] After the pre-tensioning is completed, check again whether the anchor carbon plate is intact after being stressed. After confirming that it is intact, proceed to the next step.

[0061] (7) Applying carbon plate glue: Each carbon fiber plate is bonded to the reinforced structural surface through carbon fiber plate glue to form bonding prestress, so that the new and old components are stressed together, effectively eliminating the stress lag problem of passive reinforcement and achieving the purpose of active structural reinforcement;

[0062] (8) Formal tensioning: Select the corresponding oil cylinder on the main interface of the control system and set the parameters to perform automatic tensioning operations consistent with the pre-tensioning process. The synchronous tensioning system is divided into M-stage tensioning and sets 1%-100% tensioning data. The tensioning that needs to be divided into M stages and the tension required for each stage are pre-entered in the process parameter interface; after selecting the automatic mode, the status display is consistent with the selected mode, press the start button, and use the control system to start the synchronous tensioning operation of each carbon fiber plate, and monitor the displacement and stretching movement in real time to ensure that the high-pressure oil cylinder has sufficient tensioning space; perform tensioning operations step by step according to the process requirements until the last stage is completed;

[0063] After each stage of tensioning is completed, the condition of the carbon fiber plate should be observed for at least 1-5 minutes. After reaching 100% tension stress level, the load should be held for at least 5 minutes for observation.

[0064] During the automatic tensioning operation, tensioning is performed step by step with reference to tensioning parameters, and the tensioning stages can be divided into 1-100 stages;

[0065] The tension control stress of the system should be between 0.4 and 0.7 times the design value of the carbon fiber plate material (960-1680MPa), and should not be greater than 0.7 times;

[0066] (9) After all stages are completed, fill with adhesive to repair and maintain aesthetics, and after maintaining the designed time, remove the tensioning system.

[0067] Furthermore, each of the high-pressure oil cylinders can work independently or in coordination.

[0068] Furthermore, after all stages of the tensioning work are completed, adhesive is filled for repair to maintain aesthetics and neatness, and after maintaining the designed time, the anchor is removed.

[0069] Furthermore, the synchronous tensioning system has an overload protection function. When the tensioning force exceeds a certain proportion of the set value, the tensioning is automatically stopped and an alarm is sounded.

[0070] Furthermore, the control system monitors the oil temperature, oil pressure, etc. to ensure safe operation of the system.

[0071] Furthermore, the on-site measured strength grade of the reinforced bridge concrete structural member shall not be lower than C25, and the positive tensile bond strength of the concrete surface shall not be lower than 2.0 MPa.

[0072] Furthermore, during the tensioning of the carbon fiber plate in step (6), the change in the deflection of the beam body is observed. If the deflection change is abnormal, the tensioning should be stopped and the cause should be checked.

Claims

1. A synchronous tensioning process for prestressed carbon plates for bridges, characterized in that: The steps include: (1) Determination of the number of prestressed carbon plate anchors: Design a reinforcement plan based on the actual situation of the bridge to be reinforced, adopt a prestressed carbon plate synchronous tensioning system for reinforcement, and calculate the number of prestressed carbon plate anchors N required in the synchronous tensioning system according to the tensioning stress demand of the bridge to be reinforced, where N ≥ 2; (2) Positioning and connection of prestressed carbon plate anchors: According to the construction requirements, the surface of the bridge to be reinforced is laid out according to the design drawings, and the positions of the carbon fiber plates and the fixed and tensioned anchors in the prestressed carbon plate anchors are determined. Every two prestressed carbon plate anchors are laid at equal intervals, and the base surface treatment, drilling and reinforcing bars, and carbon fiber plate cutting are completed. The two ends of the carbon fiber plates are respectively connected to the corresponding fixed end anchor anchor positions, and connected to the tensioned end anchor through high-strength tensioning screws; (3) Connection of prestressed carbon plate synchronous tensioning system: Install a high-pressure oil cylinder at the tensioning end of each prestressed carbon plate anchor, and ensure that the high-pressure oil cylinder is consistent with the center of the carbon fiber plate. Each high-pressure oil cylinder is connected to the oil circuit connector on the solenoid valve group through a pipeline, and the solenoid valve group is connected to the servo hydraulic pump station to provide a power source for the high-pressure oil cylinder; the control system is used to establish signal connections with the solenoid valve group, the servo hydraulic pump station and the high-pressure oil cylinder through the solenoid valve group signal connector, the hydraulic pump station signal connector and the displacement signal connector; (4) Synchronous tensioning system tensioning parameter setting: Turn on the system and enter the parameter setting page. Input the response parameters in combination with the technical parameters required by the design drawings. The system automatically calculates the graded tensioning stress and other parameters based on the input parameters. After the input is completed, the technical indicators are reviewed and calibrated. (5) Manual control positioning and carbon plate pre-tightening: Install the anchor plate and ensure that the center lines of the fixed end anchor plate and the tension end anchor plate are consistent. Then connect the fixed end anchor and the tension end anchor to the anchor plate respectively. Finally, switch the equipment to the pre-tightening program or manual state, and perform the pre-tightening step in the pre-tightening value setting box. The pre-tightening stress is set to 1-5KN. The synchronous tensioning system tightens the carbon fiber plate to the initial pre-tightening state, so that the state of the pulled carbon fiber plate is parallel to the bottom of the bridge. The anchor plate is fixed to the beam surface to be reinforced by high-strength chemical bolts; (6) Pre-tensioning: First, select the tensioning mode on the main interface of the control system. The tensioning mode options include manual and automatic modes. In the automatic tensioning mode, press the start button and the system will start tensioning in graded sections according to the set parameters, with graded stages 1-20. Stress is applied to the components along the tensile direction of the structure to start pre-operation. After the system tension reaches the single-stage set value, the system automatically starts to hold the load. After the holding time is reached, the next stage of tensioning will be automatically started. After the designed tensioning stress is completed, the system automatically stops and performs safety holding. After the holding time is completed, the pre-tensioning step is completed. After the pre-tensioning is completed, check again whether the anchor carbon plate is intact after being stressed, and proceed to the next step after confirming that it is intact; (7) Applying carbon plate glue: Each carbon fiber plate is bonded to the reinforced structural surface by the carbon fiber plate glue to form bonding prestress; (8) Formal tensioning: Select the corresponding cylinder on the main interface of the control system and set the parameters to perform automatic tensioning operations consistent with the pre-tensioning process. The synchronous tensioning system is divided into M-stage tensioning and sets 1%-100% tensioning data. The tensioning that needs to be divided into M stages and the tension required for each stage are pre-entered in the process parameter interface; after selecting the automatic mode, the status display is consistent with the selected mode, press the start button, and use the control system to start the synchronous tensioning operation of each carbon fiber plate, and monitor the displacement and stretching movement in real time to ensure that the high-pressure cylinder has sufficient tensioning space; perform tensioning operations step by step according to the process requirements until the last stage is completed; (9) After all stages are completed, fill with adhesive to repair and maintain aesthetics, and after maintaining the designed time, remove the tensioning system.

2. The synchronous tensioning process of prestressed carbon plates for bridges according to claim 1 is characterized in that: The design of the reinforcement scheme described in step (1) is based on the inspection of the bridge structure that has been in service for many years, combined with the actual damage of the bridge itself including cracks, damage, prestress loss, etc., the bridge grade is assessed according to the bridge inspection results, and then the design verification is carried out, and the bridge reinforcement design scheme is determined based on the verification results.

3. The synchronous tensioning process of prestressed carbon plates for bridges according to claim 1 is characterized in that: The setting out in step (2) is to set out and locate the position according to the position specified in the design drawing, accurately drill the hole position for anchor installation, and use a steel ruler to check and calibrate the position after the anchor installation is completed; The carbon fiber board in step (2) is usually 20 to 300 mm in width and 1.2 to 5 mm in thickness.

4. The synchronous tensioning process of prestressed carbon plates for bridges according to claim 1 is characterized in that: A high-precision displacement sensor is installed on the side wall of the high-pressure oil cylinder in step (3); The control system adopts an advanced programmable logic controller (PLC) as the core control unit, and the control system has both automatic control and manual control modes; The solenoid valve group is provided with N oil circuit joints, which are connected to the oil cylinders one by one through pipelines, and each oil circuit is independently controlled by a control valve to realize the operation of each hydraulic cylinder; The servo hydraulic pump station is a high-performance hydraulic pump station, and a cylinder reflux separation valve is provided on the circuit of the servo hydraulic pump station.

5. The synchronous tensioning process of prestressed carbon plates for bridges according to claim 1 is characterized in that: The technical parameters described in step (4) include the designed tensile stress, the cross-sectional area of ​​the carbon plate, the elastic modulus of the carbon plate, etc., and the response parameters include the designed tensile stress, theoretical elongation, carbon plate length, carbon plate elastic modulus, step-by-step load holding time, bridge name, construction location, etc.

6. The synchronous tensioning process of prestressed carbon plates for bridges according to claim 1 is characterized in that: The specific steps of pre-tensioning in step (6) include: firstly, applying a stress of 10% of the total tensile force to all carbon fiber plates simultaneously by using a solenoid valve group, so that the carbon fiber plates are stretched and tightened, and then entering a load holding stage. During the load holding process, the tensile stress and elongation data on the display screen are observed to be normal, and the prestressed anchors, carbon plates, anchor bolts, etc. of the bridge are detected to be normal; then, pre-tensioning is applied to each carbon fiber plate in stages by 20%, 30%, 40% until 100%, and the load is held for 1-5 minutes between each stage, and the deviation between the measured value and the calculated value is compared; when the pre-tensioning force is applied to 100%, the final tensile elongation value of the carbon fiber plate is reviewed and held for 5 minutes. After the pre-tensioning is completed, the pre-tensioning data is recorded and saved, and then the pressure is relieved and the high-pressure cylinder is retracted; the pressure relief operation first switches the system to manual mode, and long presses the retract key on the control system touch screen, and the system starts to slowly relieve pressure; the cylinder retract knob on the system panel can also be rotated in manual mode, and the cylinder can also be automatically retracted.

7. The synchronous tensioning process of prestressed carbon plates for bridges according to claim 1 is characterized in that: After each stage of tensioning in step (8) is completed, the condition of the carbon fiber plate should be observed for at least 1-5 minutes, and after reaching 100% tension stress level, the load should be maintained for at least 5 minutes for observation; During the automatic tensioning operation, tensioning is performed step by step with reference to tensioning parameters, and the tensioning stages can be divided into 1-100 stages; The tension control stress of the system is preferably between 0.4 and 0.7 times the design value of the carbon fiber plate material.

8. The synchronous tensioning process of bridge prestressed carbon plates according to claim 1 is characterized in that: The synchronous tensioning system has an overload protection function. When the tensioning force exceeds a certain proportion of the set value, the tensioning will be automatically stopped and an alarm will be issued.

9. The synchronous tensioning process of prestressed carbon plates for bridges according to claim 1 is characterized in that: The concrete structural components of the bridge to be reinforced shall have a strength grade of not less than C25 measured on site, and the positive tensile bond strength of the concrete surface shall not be less than 2.0 MPa.

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