Low-tower cable-stayed bridge cable-beam anchoring device and anchoring method

Abstract

This invention discloses an anchoring device and method for a cable-stayed bridge with a low tower. The anchoring device includes a physical anchoring unit and an intelligent monitoring node. The physical anchoring unit comprises an anchoring block and a cable guide tube. The anchoring block contains an anchor plate, a pressure distribution plate, an anti-slip shear key, and a force-transmitting steel reinforcement skeleton to distribute the tension of the cable stays into the compressive stress within the main beam. An auxiliary positioning fixture is configured externally to adjust the pre-embedded elevation and inclination angle of the physical anchoring unit. The intelligent monitoring node collects strain and cable force data and transmits them to an external terminal system. The anchoring method is as follows: the pre-embedded physical anchoring unit is positioned using the auxiliary positioning fixture; cable tensioning is performed while simultaneously collecting test data; during the system conversion stage, the external terminal system combines the elevation deviation at the closure joint, temperature, and wind load data to construct a multi-objective optimization mechanical model, calculate the optimal cable force matrix, and control the tensioning equipment to adjust the tension force. This invention achieves stress dispersion in the anchoring zone, high-precision pre-embedded positioning, and quantitative closed-loop control for bridge closure.

Description

Technical Field

[0001] This invention relates to the field of bridge engineering construction technology, specifically to an anchoring device and method for cable-stayed bridges with low towers. Background Technology

[0002] Low-tower cable-stayed bridges, a type of bridge between continuous rigid frame bridges and conventional cable-stayed bridges, have been widely used in the construction of large-span bridges spanning rivers and bays due to their engineering advantages such as large span capacity, high structural stiffness, and good construction economy. In the structural system of a low-tower cable-stayed bridge, the cable-beam anchorage zone is the key stress-bearing node connecting the stay cables and the main girder. The stay cables are fixed to the inside of the main girder through the cable-beam anchorage device, transferring the dead and live loads of the bridge deck and main girder to the bridge towers, maintaining the overall spatial stress balance of the bridge.

[0003] In existing conventional cable-stayed beam anchorage engineering practices, steel pipes or corrugated plastic pipes are typically used as pre-embedded cable guides, with anchor plates and anchorage devices placed on the outer side of the cable guide ends. On-site, the cable guides and anchor plates are first fixed to specific positions within the main beam's reinforcing steel frame, followed by the pouring of the main beam concrete. After the main beam concrete has solidified and reached the predetermined tension strength, the construction workers thread the steel strands of the stay cables through the cable guides and use tensioning equipment such as hydraulic jacks to tension the stay cables on the outer side of the anchor plates. Finally, clamps are used to lock the tensioned stay cables onto the anchor plates, completing the structural anchorage operation.

[0004] However, existing conventional cable-stayed girder anchorage methods suffer from significant local stress concentration defects in structural force transmission. After tensioning and locking, the stay cables generate enormous axial tensile forces, which typically act directly and singly on a local concrete section of the main girder through the end anchor plates. Because the bearing area of ​​conventional anchor plates is relatively limited and lacks internal stress diffusion and guiding structures extending to the web and top plate of the main girder, the highly concentrated axial load easily leads to extremely high peak stresses in the local compression zone behind the anchorage point. When the peak stress exceeds the bearing capacity of the local concrete, it can cause lateral expansion deformation or even local cracking of the anchorage zone concrete, severely weakening the load-bearing safety reserve of the cable-stayed girder anchorage joint and the overall service life of the bridge. Summary of the Invention

[0005] This invention aims to solve the technical problems of severe stress concentration in the cable-stayed bridge anchorage zone, low pre-embedded positioning accuracy, large wind vibration impact on cable stays, and lack of quantitative calculation models for cable adjustment during the construction of existing long-span, low-tower cable-stayed bridges in coastal typhoon-prone areas and complex structural system conversions.

[0006] The first aspect of this invention provides a cable-stayed bridge anchorage device for a low-tower cable-stayed bridge, comprising a physical anchorage device and an intelligent monitoring node. The physical anchorage device is located at the junction of the web and top plate of the main girder of the low-tower cable-stayed bridge, used to receive the tension force of the stay cables and distribute and transfer the tension force of the stay cables to the main girder structure. The physical anchorage device includes an anchor block and a cable guide tube disposed inside the anchor block. The intelligent monitoring node is integrated and installed at the stress concentration point of the physical anchorage device, and includes an intelligent strain gauge, an intelligent cable force tester, and a data transmission unit. The intelligent strain gauge is pre-embedded on the outside of the anchor block and at corresponding positions on the stress surface of the main girder. The intelligent cable force tester is installed at the tensioning end of the cable guide tube. The data transmission unit is electrically connected to both the intelligent strain gauge and the intelligent cable force tester.

[0007] The anchoring block comprises an anchor plate fitted onto the outer side of the cable guide end and a pressure distribution plate embedded within the main beam concrete structure. The anchor plate has a first cable-passing hole at its center, matching the inner diameter of the cable guide; the pressure distribution plate has a second cable-passing hole at its center, coaxially aligned with the first cable-passing hole. The anchor plate receives the concentrated axial tension from the tensioning end of the stay cable, while the pressure distribution plate diffuses this concentrated tension into surface compressive stress. Anti-slip shear keys are fixed to the inner end face of the pressure distribution plate, and a force-transferring steel reinforcement skeleton, including longitudinal tension bars and transverse distribution bars, is fixed to the outer edge of the pressure distribution plate. The anti-slip shear keys bear the shear and tensile stresses generated at the contact surface, and the force-transferring steel reinforcement skeleton forms a spatial grid structure within the main beam. This spatial grid structure further transmits the surface compressive stress to the distribution areas of the main beam web and top plate, limiting the transverse deformation of the main beam concrete in the concentrated compression zone. Through this structural arrangement, stress is dispersed and transferred, reducing the local peak stress level of the main beam.

[0008] The solid anchoring device is externally equipped with auxiliary positioning fixtures. These fixtures include an elevation fine-tuning device, an angle adjustment bracket, and a rigid positioning frame. The elevation fine-tuning device's lifting adjustment screw engages with the internal threaded hole of the base steel platform, controlling the overall pre-embedded elevation of the solid anchoring device. The angle control push rod of the angle adjustment bracket changes its length by extending and retracting, driving the rigid positioning frame to rotate around the hinged support, thereby locking the pre-embedded inclination angle of the cable guide. An annular clamp inside the rigid positioning frame secures the cable guide, resisting the lateral impact force generated during the pouring of the main beam concrete and ensuring the accuracy of its spatial orientation.

[0009] A temporary vibration damping structure is provided on the outer side of the cable guide. This temporary damping structure uses radially adjusting fasteners to compress internal rubber damping blocks, causing them to conform to the outer surface of the stay cable. The rubber damping blocks absorb and dissipate the lateral vibration energy generated by wind loads on the stay cable through elastic deformation. A corrosion-resistant sealing structure is provided at the exposed end face of the solid anchoring device. The protective cover of the corrosion-resistant sealing structure is tightly sealed to the sealing flange, and the interior of the protective cover is filled with a corrosion-resistant filling medium to prevent moisture and chloride ions from penetrating the interior of the protective cover.

[0010] The second aspect of this invention provides a method for anchoring the cable-stayed bridge cable beams of a low-tower cable-stayed bridge, applied to the anchoring device for the cable beams of a low-tower cable-stayed bridge provided in the first aspect of this invention. The anchoring method includes the following steps: The system is equipped with an auxiliary positioning fixture that includes an elevation fine-tuning device and an angle adjustment bracket. The auxiliary positioning fixture is used to position the solid anchoring device at the main beam formwork or cast-in-place support. The elevation fine-tuning device is used to adjust the pre-embedded elevation of the solid anchoring device, and the angle adjustment bracket is used to adjust the pre-embedded inclination angle of the cable guide. The intelligent strain gauge is fixed to the corresponding position on the outside of the anchoring block and the stress surface of the main beam. The main beam concrete is poured, and after the main beam concrete has solidified and hardened, the solid anchoring device is fixed to the steel mesh inside the main beam.

[0011] After the main beam concrete reaches its design strength, the stay cables are inserted into the cable guide tube. Temporary vibration damping structures are installed on the outer side of the cable guide tube ends to limit the lateral vibration of the stay cables. Working anchor plates and working clamps are sequentially fitted onto the tensioning end of the stay cables. An intelligent cable force tester is installed at the tensioning end of the cable guide tube. Initial tension is applied to the stay cables using tensioning equipment. Strain test data is collected by intelligent strain gauges, and tension cable force values ​​are collected by the intelligent cable force tester. The strain test data and tension cable force values ​​are synchronously transmitted to an external terminal system using a data transmission unit.

[0012] The structural system transformation was completed by dismantling the temporary fixed structure of the low-tower cable-stayed bridge on-site. The external terminal system used the design internal force value of the main girder of the low-tower cable-stayed bridge under single cantilever stress as the control target, and calculated the secondary cable adjustment command by combining strain test data and tension cable force values. During the calculation of the secondary cable adjustment command, the external terminal system received the actual elevation data, temperature data, and wind load data of the closure joint, and compared the actual elevation data with the design elevation of the closure joint to obtain the elevation deviation value of the closure joint.

[0013] An external terminal system constructs a multi-objective optimization mechanical model by combining temperature and wind load data. The multi-objective optimization mechanical model has two optimization objectives: minimizing the elevation deviation at the closure point and ensuring the internal force state of the main girder meets design requirements. The secondary adjustment cable force of the stay cables is used as the optimization variable, and the material stress limits of the main girder and bridge towers are used as safety constraints. The external terminal system uses a genetic algorithm combined with a finite element method to solve the multi-objective optimization mechanical model, calculating the optimal adjustment cable force matrix to eliminate the elevation deviation at the closure point. The tensioning equipment generates secondary adjustment commands based on the optimal adjustment cable force matrix and adjusts the tension of the stay cables according to these commands. After the tension of the stay cables is adjusted, a corrosion-resistant sealing structure is installed at the exposed end face of the physical anchoring device.

[0014] This invention provides an anchoring device and method for cable-stayed bridge beams with low towers. It has the following beneficial effects: 1. This invention, by setting an anchor plate sleeved on the end of the cable guide tube inside the anchor block and a pressure distribution plate pre-embedded inside the main beam, combined with an anti-slip shear key fixed to the inner side of the pressure distribution plate and a spatial grid force transmission steel skeleton composed of longitudinal and transverse steel bars welded together, transforms the axial concentrated tensile force at the tensioning end of the cable into surface compressive stress and further diffuses and transmits it to the distribution area of ​​the web and top plate of the main beam. This achieves the stress dispersion and transmission effect of reducing the peak stress level in the compression zone of the main beam of the low-tower cable-stayed bridge and limiting the transverse deformation of the concrete in the concentrated compression zone.

[0015] 2. This invention utilizes auxiliary positioning fixtures configured outside the physical anchoring device. The pre-embedded elevation is controlled by the threaded engagement of the base steel platform and the lifting adjustment screw in the elevation fine-tuning device. Simultaneously, the telescopic structure of the angle adjustment bracket drives the rigid positioning frame to rotate around the hinged support to lock the pre-embedded inclination angle of the cable guide. Combined with the clamping and fixing of the outer wall of the cable guide by the annular clamp, this invention achieves the construction pre-embedding effect of resisting the lateral impact force generated during the pouring of the main beam concrete and ensuring the precise three-dimensional positioning of the cable guide and anchor block inside the bridge structure.

[0016] 3. This invention transmits test data, along with on-site temperature and wind load data, collected by intelligent strain gauges and intelligent cable force testers integrated into the physical anchoring device to an external terminal system. Combined with the elevation deviation value of the closure joint, an optimized mechanical model is constructed with the dual objectives of minimizing the elevation deviation and ensuring that the internal forces of the main beam meet the requirements. The optimal cable force matrix is ​​obtained using a genetic algorithm, and cable adjustment commands are generated to control the tensioning equipment to perform tension force adjustment operations. This achieves a closed-loop feedback adjustment effect for high-precision closure and quantitative control of the stress state of the completed bridge in complex environments and system transformation processes of low-tower cable-stayed bridges. Attached Figure Description

[0017] Figure 1 This is a flowchart of the cable-stayed bridge anchorage method for low-tower cable-stayed bridges according to the present invention. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example: Please see the appendix Figure 1 This invention provides a cable-stayed bridge cable-stayed beam anchorage system with low towers, comprising: Solid anchoring devices, auxiliary positioning fixtures, and intelligent monitoring nodes.

[0020] The solid anchorage device is located at the junction of the web and top plate of the main girder of the low-tower cable-stayed bridge. The solid anchorage device is used to bear the tension force of the stay cables and distribute the tension force of the stay cables to the main girder structure.

[0021] The solid anchoring device includes anchor blocks, cable guides, temporary vibration damping structures, and corrosion-resistant sealing structures.

[0022] The anchor blocks are connected to the steel mesh inside the main beam. The anchor blocks are used to reduce the shear and tensile stresses generated at the contact surface of the main beam during the tensioning of the stay cables.

[0023] The cable guide tube is located inside the anchor block. It provides a channel for the stay cables to pass through and for spatial angular positioning. A temporary vibration damping structure is installed on the outer end of the cable guide tube. This temporary vibration damping structure includes a damping pad and damping energy dissipation components. The temporary vibration damping structure is used to reduce the vibration amplitude caused by wind loads during the cable passing and hanging stages.

[0024] The corrosion-resistant sealing structure is installed on the exposed end face of the solid anchoring device. The corrosion-resistant sealing structure includes a corrosion-resistant cover and a sealing gasket. The corrosion-resistant sealing structure is used to isolate external moisture and protect the internal components of the solid anchoring device.

[0025] The auxiliary positioning fixture is installed outside the solid anchoring device. The auxiliary positioning fixture is used to fix and adjust the spatial posture of the solid anchoring device before concrete pouring.

[0026] The auxiliary positioning fixture includes an angle adjustment bracket and an elevation fine-tuning device.

[0027] Angle adjustment bracket connects to the outer wall of the cable guide pipe to adjust the pre-embedded inclination angle of the cable guide pipe. Elevation fine-tuning device is supported on the main beam formwork or cast-in-place support to control the overall pre-embedded elevation of the solid anchoring device.

[0028] The intelligent monitoring node is integrated and installed at the stress concentration points of the physical anchoring device. The intelligent monitoring node is used to collect mechanical state data in real time during the tensioning and anchoring process.

[0029] The intelligent monitoring node includes intelligent strain gauges, intelligent cable force testers, and data transmission units.

[0030] Intelligent strain gauges are pre-embedded on the outer side of the anchoring block and at corresponding positions on the stress surface of the main beam. These intelligent strain gauges are used to measure strain data in the anchoring zone in real time.

[0031] The intelligent cable force tester is installed at the tensioning end of the cable guide tube. It is used to simultaneously acquire the tension force values ​​of the stay cables.

[0032] The data transmission unit is electrically connected to both the intelligent strain gauge and the intelligent cable force tester. The data transmission unit is used to synchronously transmit the collected strain test data and tension cable force values ​​to an external terminal system.

[0033] This invention provides a method for anchoring the cable-stayed bridge beams of a low-tower cable-stayed bridge, comprising: Step S1: Use auxiliary positioning fixtures to position the solid anchoring device on the main beam formwork or cast-in-place support. Adjust the pre-embedded elevation of the solid anchoring device using the elevation fine-tuning device. Adjust the pre-embedded inclination angle of the cable guide using the angle adjustment bracket. Fix the intelligent strain gauge to the corresponding position on the outside of the anchoring block and the stress surface of the main beam. Pour the main beam concrete. After the main beam concrete has solidified and hardened, the solid anchoring device is fixed to the steel mesh inside the main beam.

[0034] Step S2: After the main beam concrete reaches the design strength, the stay cables are inserted into the cable guide tube. Temporary vibration damping structures are installed on the outer side of the end of the cable guide tube to laterally limit the stay cables.

[0035] Step S3: Install an intelligent cable force tester at the tensioning end of the cable guide tube, apply initial tension force to the stay cable using the tensioning equipment, collect strain test data of the anchorage zone using an intelligent strain gauge, collect the tension cable force value of the stay cable using the intelligent cable force tester, and use the data transmission unit to synchronously send the strain test data and tension cable force value to the external terminal system.

[0036] Step S4: Release the temporary fixed structure of the low-tower cable-stayed bridge to complete the structural system conversion. Utilize the external terminal system to calculate the secondary cable adjustment command based on strain test data, tension cable force values, and the bridge's design target state. Adjust the tension of the cable stays according to the secondary cable adjustment command. After the tension of the cable stays is adjusted, install an anti-corrosion sealing structure on the exposed end face of the physical anchorage device.

[0037] This invention provides a stress dispersion and bearing component for a cable-beam joint, comprising: Anchor blocks are installed inside the main girder of the low-tower cable-stayed bridge. Anchor blocks include anchor plates, pressure distribution plates, anti-slip shear keys, and force-transfer steel reinforcement cages.

[0038] An anchor plate is fitted onto the outer side of the end of the cable guide tube. The center of the anchor plate has a first cable-passing hole that matches the inner diameter of the cable guide tube. The inner end face of the anchor plate is fixedly connected to the outer end face of the pressure distribution plate. The anchor plate bears the axial concentrated tensile force at the tensioning end of the stay cable.

[0039] The pressure distribution plate is embedded inside the main beam concrete structure. The outer contour dimension of the pressure distribution plate is larger than that of the anchor plate. A second cable-passing hole, coaxially aligned with the first cable-passing hole, is provided at the center of the pressure distribution plate. The second cable-passing hole and the first cable-passing hole jointly connect to the internal channel of the cable guide. The pressure distribution plate diffuses the axial concentrated tensile force into surface compressive stress.

[0040] The anti-slip shear keys are welded and fixed to the inner end face of the pressure distribution plate. The anti-slip shear keys extend along the axial direction of the cable guide and are arranged in a matrix.

[0041] The anti-slip shear key is interlocked and fixed to the main beam concrete structure. The anti-slip shear key bears the shear and tensile stresses generated at the contact surface between the load-bearing distribution plate and the main beam concrete.

[0042] The reinforcing steel cage is welded and fixed to the outer edge of the pressure distribution plate. The reinforcing steel cage is distributed outward along the extension direction of the web and top plate of the main beam.

[0043] The load-bearing steel reinforcement cage intersects and is tied to the internal structural steel reinforcement mesh of the main beam in a staggered manner. The load-bearing steel reinforcement cage transfers the surface compressive stress to the distribution areas of the main beam web and the top plate of the main beam.

[0044] The reinforcing steel cage consists of longitudinal tension bars (a) and transverse distribution bars (b). The longitudinal tension bars (a) are arranged parallel to the longitudinal force axis of the main beam. The transverse distribution bars (b) are perpendicular to and staggered outside the longitudinal tension bars (a).

[0045] The longitudinal tension reinforcement a and the transverse distribution reinforcement b are welded and fixed at the intersection. The longitudinal tension reinforcement a and the transverse distribution reinforcement b together form a spatial grid structure.

[0046] A spatial grid structure is embedded within the main beam concrete structure. The spatial grid structure restricts the lateral deformation of the main beam concrete in the concentrated compression zone.

[0047] This invention provides a three-dimensional precision positioning component for cable catheters, comprising: The auxiliary positioning fixture is installed on the base of the main beam formwork for the low-tower cable-stayed bridge. The auxiliary positioning fixture is used to fix the spatial position of the cable guide pipes before the main beam concrete is poured.

[0048] The auxiliary positioning fixture includes an elevation fine-tuning device, an angle adjustment bracket, and a rigid positioning frame.

[0049] The elevation adjustment device is supported on the load-bearing surface of the main beam formwork. The elevation adjustment device includes a base steel platform and a lifting and adjusting screw.

[0050] The lifting and adjusting screw passes vertically through the base steel platform. An internal threaded hole, matching the external thread of the lifting and adjusting screw, is located at the center of the base steel platform. The top end of the lifting and adjusting screw is fixedly connected to the bottom of the angle adjusting bracket.

[0051] The lifting and adjusting screw changes the angle by screwing in the thread, adjusting the overall elevation of the bracket in the vertical direction.

[0052] The angle adjustment bracket includes a base plate, a hinged support, and an angle control push rod.

[0053] The supporting base plate is welded and fixed to the top of the lifting and adjusting screw. The hinged support is installed at the center of the upper surface of the supporting base plate.

[0054] The lower end of the angle control push rod is rotatably connected to the edge of the supporting base plate. The upper end of the angle control push rod is rotatably connected to the side wall of the rigid positioning frame.

[0055] The angle control push rod is a telescopic sleeve structure with a locking nut. The angle control push rod adjusts its length by telescoping, thereby driving the stiffening positioning frame to rotate around the hinged support. After the length adjustment is complete, the locking nut locks the pre-embedded inclination angle of the cable guide.

[0056] The rigid positioning frame is installed on top of the hinged support. The interior of the rigid positioning frame forms a fixed space to accommodate the cable guide.

[0057] The rigid positioning frame comprises multiple annular clamps evenly distributed along the axial direction of the cable guide tube and longitudinal support rods. The longitudinal support rods are welded and fixed to the outer side of the multiple annular clamps.

[0058] A ring-shaped clamp is fitted and secured to the outer wall of the cable guide. Longitudinal support rods are tied and fixed to the internal structural steel mesh of the main beam. A rigid positioning frame is used to resist the lateral impact forces generated during the pouring of the main beam concrete.

[0059] Multiple branch tubes are threaded inside the cable guide tube. The branch tubes are arranged parallel to the axis of the cable guide tube. The branch tubes provide passageways for individual stay cable strands.

[0060] A grid protective cover is installed at the top opening of the cable conduit. The grid protective cover is welded and fixed to the end edge of the cable conduit.

[0061] The grating protective cover covers the top opening of the wire-splitting tube. The grating protective cover is used to prevent concrete slurry and welding slag from falling into the cable guide tube.

[0062] This invention provides a temporary typhoon-resistant vibration reduction and anchoring protection structure, comprising: The temporary vibration damping structure is installed on the outside of the top opening of the cable guide tube. The temporary vibration damping structure is used to limit the lateral vibration of the stay cable before final tensioning.

[0063] The temporary vibration damping structure includes a sleeve support, rubber damping blocks, and radial adjustment fasteners.

[0064] The bottom end of the sleeve support is fixedly connected to the outer wall of the cable guide tube. The sleeve support is arranged around the exit path of the stay cable.

[0065] A rubber damping block is installed between the inner wall of the sleeve support and the outer surface of the stay cable. The inner surface of the rubber damping block is in contact with the outer surface of the stay cable.

[0066] Rubber damping blocks have elastic deformation capabilities. They absorb and dissipate the lateral vibration energy generated by wind loads on the stay cables.

[0067] The sleeve support has a radially penetrating threaded hole on its side wall. The radially adjusting fastener is threaded into the threaded hole. The inner end of the radially adjusting fastener abuts against the outer surface of the rubber damping block.

[0068] The radial adjusting fastener is screwed into the rubber damping block via a thread. The radial adjusting fastener adjusts the clamping constraint force of the rubber damping block on the stay cable.

[0069] The corrosion-resistant sealing structure is installed at the exposed anchoring end of the solid anchoring device. This structure prevents external moisture and chloride ions from penetrating the interior of the solid anchoring device.

[0070] The corrosion-resistant sealing structure includes a sealing connection flange, a protective cover, and a corrosion-resistant filling medium.

[0071] The sealing flange is fixedly installed on the outer end face of the anchor block. The sealing flange is arranged around the anchor end of the stay cable.

[0072] The bottom opening of the protective cover is bolted to the sealing flange for a sealed connection. The interior of the protective cover forms a closed, enclosing cavity. The anchoring ends of the stay cables are located inside this cavity.

[0073] The top of the protective cover has a hole for the stay cable to pass through. A waterproof sealing ring is installed at the edge of the hole. The waterproof sealing ring is tightly fitted to the outer surface of the stay cable.

[0074] The corrosion-resistant filling medium fills the cavity inside the protective cover. It also wraps around the anchoring end and exposed end of the stay cable. The medium isolates the cable from air and moisture.

[0075] This invention provides an adjustable positioning and high-precision pre-embedding process for anchoring cable-stayed bridge beams of low-tower bridges, comprising: The elevation adjustment device of the auxiliary positioning fixture is supported on the load-bearing surface of the main beam formwork.

[0076] The physical anchoring device is hoisted above the elevation fine-tuning device. The cable guide is inserted into the internal fixing space of the rigid positioning frame. The outer wall of the cable guide is clamped and fixed using a ring clamp.

[0077] The elevation data of the physical anchoring device is monitored in real time using measuring instruments. The lifting and adjusting screw of the rotating elevation fine-tuning device is screwed inwards within the steel base. The lifting and adjusting screw drives the angle adjusting bracket to move vertically. The screwing depth is continuously adjusted according to the elevation data until the physical anchoring device reaches the designed pre-embedded elevation.

[0078] The inclination angle data of the cable guide tube is monitored in real time using measuring instruments. The angle of the angle adjustment bracket controls the extension and retraction length of the push rod. The angle control push rod drives the stiffening positioning frame to rotate around the hinged support, thereby causing the cable guide tube to rotate synchronously.

[0079] After the cable guide reaches the designed pre-embedded inclination angle, tighten the locking nut of the angle control push rod to lock the spatial position of the cable guide.

[0080] The longitudinal support rods of the rigid positioning frame are tied and fixed to the structural steel mesh inside the main beam.

[0081] The force-transmitting steel reinforcement cage of the anchor block is intersected and tied to the structural steel reinforcement mesh inside the main beam.

[0082] The intelligent strain gauges are fixed to the outside of the anchor block and at corresponding positions on the load-bearing surface of the main beam.

[0083] A fixed grid protective cover is welded to the top opening of the cable conduit.

[0084] Pour the main beam concrete. After the main beam concrete has solidified and hardened, the solid anchoring device, intelligent strain gauge and the structural steel mesh inside the main beam form a whole for bearing the load and are fixed inside the main beam concrete.

[0085] This invention provides a method for anchoring cable-stayed bridge cables with low towers, including the following construction steps: cable threading, tensioning, and temporary vibration reduction: After the main beam concrete reaches its design strength, remove the grid protective cover at the top opening of the cable guide pipe.

[0086] The steel strands of the stay cable are threaded into the cable guide tube. Each steel strand is then passed through its corresponding branch tube inside the cable guide tube.

[0087] The stay cable passes through the anchor block of the solid anchoring device. The stay cable extends to the preset tensioning operation area.

[0088] Install a temporary vibration damping structure on the outside of the top opening of the cable conduit. Fix the sleeve support of the temporary vibration damping structure to the outer wall of the cable conduit.

[0089] The rubber damping blocks of the temporary vibration reduction structure are placed between the inner wall of the sleeve support and the outer surface of the cable.

[0090] The radial adjusting fastener of the temporary vibration damping structure is screwed in. The radial adjusting fastener is pushed inward and compresses the rubber damping block.

[0091] The rubber damping block deforms under pressure and fits tightly against the outer surface of the stay cable. The temporary vibration reduction structure limits the lateral vibration of the stay cable under wind load.

[0092] Working anchor plates and working clamps are sequentially inserted into the tensioning end of the cable.

[0093] A smart cable force tester is installed at the tensioning end of the cable guide tube. The smart cable force tester is sleeved on the outside of the stay cable and abuts against the working anchor plate.

[0094] A tensioning device is installed on the outside of the intelligent cable tension tester. The tensioning device is connected to the end of the stay cable.

[0095] Start the tensioning equipment. The tensioning equipment applies initial tension force to the stay cables.

[0096] During the operation of the tensioning equipment, intelligent strain gauges collect strain test data in real time on the outer side of the anchor block and the stress surface of the main beam.

[0097] The intelligent cable force tester collects the tension force values ​​of the stay cables in real time.

[0098] When the tension cable force value displayed by the intelligent cable force tester reaches the initial design tension force, the tensioning equipment stops working.

[0099] The stay cables are locked in place by retracting the working clamps. The tension of the stay cables is transferred to the interior of the main beam structure through a solid anchoring device.

[0100] This invention provides a method for anchoring cable-stayed bridge cables with low towers, which combines intelligent monitoring with tension early warning and cable force adjustment steps, including: During the process of applying initial tension force to the stay cables, the intelligent strain gauge collects strain test data in real time on the outside of the physical anchoring device and the stress surface of the main beam.

[0101] The intelligent cable force tester simultaneously collects the tension force values ​​of the stay cables.

[0102] The data transmission unit transmits strain test data and tension cable force values ​​to an external terminal system in real time via a communication network.

[0103] The external terminal system pre-stores the theoretical values ​​of design strain, theoretical values ​​of design cable force, strain warning threshold, and cable force warning threshold corresponding to the current construction stage of the low-tower cable-stayed bridge.

[0104] The external terminal system compares the received strain test data with the theoretical design strain value to obtain the strain deviation value.

[0105] The external terminal system compares the received tension cable force value with the theoretical value of the designed cable force to obtain the cable force deviation value.

[0106] The external terminal system determines whether the strain deviation value exceeds the strain warning threshold, and at the same time determines whether the cable force deviation value exceeds the cable force warning threshold.

[0107] When the strain deviation exceeds the strain warning threshold, the external terminal system issues the first shutdown warning command. The tensioning equipment receives the first shutdown warning command and stops the tensioning operation of the stay cables.

[0108] When the cable tension deviation exceeds the cable tension warning threshold, the external terminal system issues a second shutdown warning command. The tensioning equipment receives the second shutdown warning command and stops the tensioning operation of the stay cables.

[0109] After the tensioning equipment stops tensioning, the external terminal system establishes an influence matrix mechanical model that includes strain deviation values ​​and cable force deviation values. The external terminal system performs iterative calculations by solving the influence matrix mechanical model and outputs cable adjustment compensation commands under the current working conditions.

[0110] The tensioning equipment receives cable adjustment compensation commands. Based on these commands, the tensioning equipment performs additional tensioning or unloading operations on the stay cables.

[0111] During tensioning or unloading operations, the intelligent strain gauge and intelligent cable force tester continuously collect and send updated strain test data and tension cable force values ​​to the external terminal system.

[0112] The external terminal system repeatedly executes the deviation value calculation and threshold judgment steps until the strain deviation value is within the strain warning threshold range and the cable force deviation value is within the cable force warning threshold range, at which point the tension warning and cable force adjustment steps end.

[0113] This invention provides a method for anchoring cable-stayed bridge cables under a pier-beam hinged tower-beam consolidation system, comprising the following steps for controlling the anchoring force: The temporary fixed supports between the main pier and the main girder of the low-tower cable-stayed bridge were removed on-site by dismantling equipment. During the removal of the temporary fixed supports, the low-tower cable-stayed bridge changed from a double cantilever stress state to a single cantilever stress state, resulting in a redistribution of bending moment and shear force within the main girder.

[0114] The redistributed bending moment and shear force within the main beam are transferred to the solid anchorage device. The anchor blocks of the solid anchorage device bear the redistributed stress caused by the system transformation.

[0115] The bearing pressure distribution plate and anti-slip shear key inside the anchor block disperse the redistributed stress into the concrete structure of the main beam. The force-transfer reinforcement cage transfers the concentrated stress at the anchor block to the distribution area of ​​the main beam web and the top plate of the main beam.

[0116] During the removal of temporary fixed supports, intelligent strain gauges continuously collected real-time strain data from the outer side of the physical anchorage device and the stress surface of the main beam. Simultaneously, an intelligent cable force tester continuously collected real-time cable force data from the stay cables.

[0117] The data transmission unit sends real-time strain data and real-time cable force data to an external terminal system.

[0118] The external terminal system receives real-time strain data and real-time cable force data, and calculates the rate of change of stress and cable force during the system transformation process.

[0119] The external terminal system determines whether the rate of change of stress exceeds the preset system conversion strain safety threshold, and at the same time determines whether the rate of change of cable force exceeds the preset system conversion cable force safety threshold.

[0120] When the rate of change of stress exceeds the system's transition strain safety threshold, or the rate of change of cable force exceeds the system's transition cable force safety threshold, the external terminal system issues a stop-work command. The on-site dismantling equipment receives the stop-work command and ceases the work of removing temporary fixed supports.

[0121] The external terminal system extracts real-time strain data and real-time cable force data, and inputs them into the calculation model of the pier-beam hinged tower-beam solidified structure for internal force analysis.

[0122] The external terminal system uses the design internal force value of the main beam of the low-tower cable-stayed bridge under single cantilever stress as the control target, and calculates the cable force compensation value under the current deviation state through the calculation model of the pier-beam hinged tower-beam solidified structure.

[0123] The external terminal system outputs a system conversion and transition cable adjustment command based on the cable force compensation value. The tensioning equipment receives the system conversion and transition cable adjustment command.

[0124] The tensioning equipment performs tension adjustment operations on the stay cables according to the system conversion and transition cable adjustment command.

[0125] The intelligent strain gauge and intelligent cable force tester continuously collect and send real-time strain data and real-time cable force data after adjustment operations to an external terminal system.

[0126] After the real-time strain data and real-time cable force data are restored to the theoretical safety design range of the single cantilever stress state, the on-site dismantling of equipment continues the construction work of removing the temporary fixed supports, and the overall structural system conversion is completed.

[0127] This invention provides an optimal cable adjustment step based on the closure elevation of a cable-stayed bridge with a low tower, comprising the following steps: Before the main girder closure section of the low-tower cable-stayed bridge was poured, on-site measuring equipment acquired the actual elevation data of the main girder closure joint and sent the actual elevation data to an external terminal system.

[0128] Environmental monitoring equipment collects temperature and wind load data at the construction site and sends the temperature and wind load data to an external terminal system.

[0129] The intelligent strain gauge collects real-time strain data on the outside of the solid anchoring device and the stress surface of the main beam.

[0130] The intelligent cable force tester synchronously collects the current cable force data of the stay cables.

[0131] The data transmission unit transmits the current strain data and current cable force data to the external terminal system.

[0132] The external terminal system receives the actual elevation data, current strain data, current cable force data, temperature data, and wind load data of the closure section.

[0133] The external terminal system compares the actual elevation data with the design elevation of the closure joint and calculates the elevation deviation value of the closure joint.

[0134] An external terminal system combines temperature and wind load data to construct a multi-objective optimization mechanical model. The multi-objective optimization mechanical model has two optimization objectives: minimizing the elevation deviation at the closure point and ensuring that the internal force state of the main girder meets the design requirements. The secondary cable tension of the stay cables is used as the optimization variable, and the material stress limits of the main girder and bridge towers are used as safety constraints.

[0135] The external terminal system uses a genetic algorithm combined with a finite element method to solve the multi-objective optimization mechanical model.

[0136] The external terminal system obtains the optimal cable adjustment force matrix to eliminate the elevation deviation at the closure point by solving the calculation.

[0137] The external terminal system generates a secondary cable adjustment command based on the optimal cable force matrix and sends the secondary cable adjustment command to the tensioning equipment.

[0138] The tensioning equipment receives secondary cable adjustment commands. Based on these commands, the tensioning equipment performs supplementary tensioning or unloading operations on specific stay cables at the physical anchorage.

[0139] During the operation of the tensioning equipment, the intelligent cable force tester and intelligent strain gauge continuously collect real-time cable force data and real-time strain data, and feed them back to the external terminal system.

[0140] The external terminal system monitors the real-time cable force data until the real-time cable force data reaches the target cable force value specified by the optimal cable force adjustment matrix.

[0141] After the cable tension adjustment of the stay cables was completed, the on-site measuring equipment remeasured the elevation data of the main beam closure joint.

[0142] After the elevation data met the design elevation requirements of the closure section, the on-site construction equipment carried out the concrete pouring operation for the main beam closure section.

[0143] 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.

Claims

1. An anchoring device for cable-stayed bridges with low towers, characterized in that, include: A solid anchorage device is installed at the junction of the web and top plate of the main girder of the low-tower cable-stayed bridge. It is used to receive the tension force of the cable stays and distribute the tension force of the cable stays to the main girder structure. The solid anchorage device includes an anchor block and a cable guide tube installed inside the anchor block. The anchor block is connected to the steel mesh inside the main girder. The intelligent monitoring node, integrated and installed at the stress concentration point of the physical anchoring device, includes an intelligent strain gauge, an intelligent cable force tester, and a data transmission unit. The intelligent strain gauge is pre-embedded on the outer side of the anchoring block and at corresponding positions on the stress surface of the main beam. The intelligent cable force tester is installed at the tensioning end of the cable guide tube. The data transmission unit is electrically connected to both the intelligent strain gauge and the intelligent cable force tester to synchronously transmit strain test data and tension cable force values.

2. The cable-stayed bridge cable-stayed beam anchorage device according to claim 1, characterized in that, The anchor block includes an anchor plate and a pressure distribution plate; The anchor plate is sleeved on the outer side of the end of the cable guide, and the center of the anchor plate is provided with a first cable-passing hole that matches the inner diameter of the cable guide; the pressure distribution plate is embedded in the concrete structure of the main beam, and its outer contour dimension is larger than that of the anchor plate. The inner end face of the anchor plate is fixedly connected to the outer end face of the pressure distribution plate; the center of the pressure distribution plate is provided with a second cable-passing hole that is coaxially aligned with the first cable-passing hole, and the second cable-passing hole and the first cable-passing hole are connected to the internal channel of the cable guide.

3. The cable-stayed bridge cable-stayed beam anchoring device according to claim 2, characterized in that, The anchor block also includes anti-slip shear keys and a force-transmitting steel reinforcement skeleton; The anti-slip shear key is welded and fixed to the inner end face of the pressure distribution plate, extends along the axial direction of the cable guide and is arranged in a matrix, and is interlocked and fixed with the main beam concrete structure. The force-transmitting steel reinforcement skeleton is welded and fixed to the outer edge of the pressure-bearing distribution plate, and includes longitudinal tension bars a arranged parallel to the longitudinal force axis of the main beam and transverse distribution bars b perpendicularly intersecting the outer side of the longitudinal tension bars a; the longitudinal tension bars a and the transverse distribution bars b are welded and fixed at the intersection node, together forming a spatial grid structure embedded in the concrete structure of the main beam.

4. The cable-stayed bridge cable-stayed beam anchorage device according to claim 1, characterized in that, It also includes auxiliary positioning fixtures; The auxiliary positioning fixture is set outside the solid anchoring device and includes an angle adjustment bracket and an elevation fine adjustment device; the angle adjustment bracket is connected to the outer wall of the cable guide and is used to adjust the pre-embedded inclination angle of the cable guide; the elevation fine adjustment device is supported on the main beam formwork or cast-in-place support and is used to control the overall pre-embedded elevation of the solid anchoring device.

5. The cable-stayed bridge cable-stayed beam anchorage device according to claim 4, characterized in that, The elevation fine-tuning device includes a base steel platform and a lifting adjustment screw; the base steel platform has an internal threaded hole at its center, and the lifting adjustment screw is threaded into the internal threaded hole in the vertical direction; The angle adjustment bracket includes a support base plate, a hinged support, and an angle control push rod; the support base plate is welded and fixed to the top end of the lifting adjustment screw, and the hinged support is installed at the center of the upper surface of the support base plate; the lower end of the angle control push rod is rotatably connected to the edge of the support base plate.

6. The cable-stayed bridge cable-stayed beam anchoring device according to claim 5, characterized in that, The auxiliary positioning fixture also includes a rigid positioning frame installed on the top of the hinge support. The rigid positioning frame includes multiple annular clamps equidistantly distributed along the axial direction of the cable guide and longitudinal support rods welded and fixed to the outside of the multiple annular clamps; the annular clamps are sleeved and fastened to the outer wall of the cable guide. The angle control push rod is a telescopic sleeve structure with a locking nut. The upper end of the angle control push rod is rotatably connected to the side wall of the rigid positioning frame. By telescopically adjusting its own length, the rigid positioning frame is driven to rotate around the hinge support.

7. The cable-stayed bridge cable-stayed beam anchoring device according to claim 1, characterized in that, The outer side of the end of the cable guide is provided with a temporary vibration damping structure; The temporary vibration damping structure includes a sleeve bracket, a rubber damping block, and a radial adjustment fastener; the bottom end of the sleeve bracket is fixedly connected to the outer wall of the cable guide, and the side wall of the sleeve bracket has a radially penetrating threaded hole. The rubber damping block is disposed between the inner wall of the sleeve bracket and the outer surface of the cable; the radial adjustment fastener is threadedly engaged with the threaded hole, and the inner end of the radial adjustment fastener abuts against and presses against the outer surface of the rubber damping block.

8. The cable-stayed bridge cable-stayed beam anchorage device according to claim 1, characterized in that, The exposed end face of the solid anchoring device is provided with an anti-corrosion sealing structure; The anti-corrosion sealing structure includes a sealing connection flange, a protective cover, and an anti-corrosion filling medium; the sealing connection flange is fixedly installed on the outer end face of the anchor block; the bottom opening of the protective cover is connected to the sealing connection flange by bolts; the top of the protective cover is provided with a cable through hole with a waterproof sealing ring; the anti-corrosion filling medium fills the closed cavity inside the protective cover.

9. The cable-stayed bridge cable-stayed beam anchoring device according to claim 1, characterized in that, The cable guide tube is internally provided with multiple branch tubes arranged parallel to each other along the axial direction; a grid protective cover is welded and fixed at the top opening of the cable guide tube, and the grid protective cover covers the top opening of the branch tubes.

10. A method for anchoring the cable-stayed bridge cable beams of a low-tower cable-stayed bridge, applied to an anchoring device for a low-tower cable-stayed bridge cable beam as described in any one of claims 1 to 9, characterized in that, The anchoring method includes the following steps: Step S1: Configure an auxiliary positioning fixture including an elevation fine-tuning device and an angle adjustment bracket; use the auxiliary positioning fixture to position the solid anchoring device at the main beam formwork or cast-in-place support location; adjust the pre-embedded elevation of the solid anchoring device through the elevation fine-tuning device; adjust the pre-embedded inclination angle of the cable guide through the angle adjustment bracket; fix the intelligent strain gauge to the corresponding position on the outside of the anchoring block and the stress surface of the main beam; pour the main beam concrete; after the main beam concrete has solidified and hardened, the solid anchoring device is fixed to the steel mesh inside the main beam. Step S2: After the main beam concrete reaches the design strength, the stay cables are inserted into the cable guide tube, and a temporary vibration damping structure is installed on the outer side of the end of the cable guide tube to limit the lateral vibration of the stay cables. Step S3: Insert the working anchor plate and working clamp into the tension end of the cable in sequence, install the intelligent cable force tester at the tension end of the cable guide tube, apply the initial tension force to the cable using the tensioning equipment, collect the strain test data through the intelligent strain gauge, collect the tension cable force value through the intelligent cable force tester, and use the data transmission unit to synchronously send the strain test data and the tension cable force value to the external terminal system. Step S4: The temporary fixed structure of the low-tower cable-stayed bridge is removed by dismantling equipment on site to complete the structural system conversion. The external terminal system uses the design internal force value of the main beam of the low-tower cable-stayed bridge under single cantilever stress as the control target. Combined with strain test data and tension cable force values, the secondary cable adjustment command is calculated. The tensioning equipment adjusts the tension of the cable according to the secondary cable adjustment command. After the tension of the cable is adjusted, an anti-corrosion sealing structure is installed at the exposed end face of the physical anchoring device.

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