A pier-top prefabricated anchored lifting box girder dismantling support device

Abstract

This invention discloses a prefabricated anchored lifting box girder dismantling support device for pier tops, belonging to the technical field of bridge dismantling auxiliary equipment. It includes: a prefabricated Bailey beam support assembly, a top anchoring beam assembly, a deep anchoring assembly at the pier top, a hydraulic synchronous lifting assembly, and a steel strand suspension load-bearing assembly. The prefabricated Bailey beam support assembly is laid on the top surface of the box girder, serving as the load-bearing base of the device. The top anchoring beam assembly is horizontally erected on top of the prefabricated Bailey beam support assembly. The deep anchoring assembly at the pier top is vertically embedded inside the top of the pier. This invention, by employing a deep grouting anchoring structure at the pier top, achieves a rigid connection between the device and the pier body through integral consolidation with precision-rolled threaded steel bars and the pier concrete. This completely eliminates the frictional stabilization mode of traditional self-weight supports, significantly improving anti-slip, anti-overturning, and anti-settlement performance, effectively avoiding local instability and uneven settlement under large loads, and greatly increasing construction safety redundancy.

Description

Technical Field

[0001] This invention relates to the field of bridge demolition auxiliary equipment technology, specifically to a pier-top assembled anchored lifting box girder demolition support device. Background Technology

[0002] In existing bridge reconstruction and expansion projects, defect treatment, and dangerous bridge demolition projects, cast-in-place box girder demolition operations generally use ground-mounted steel pipe scaffolding devices as temporary support structures. By erecting full-span scaffolding under the beam to bear the self-weight load of the box girder, and cooperating with hoisting equipment to complete segment cutting and transportation, the demolition work is carried out with load-bearing support, ensuring the structural stability and construction safety of the operation process.

[0003] However, in the overall dismantling of box girders under complex urban conditions, traditional supports are self-weight temporary structures without rigid anchoring. They rely solely on ground friction and their own weight to maintain stability, resulting in poor resistance to slippage, overturning, and settlement. Under heavy loads, they are prone to local instability and uneven settlement. Furthermore, the supports are mostly assembled on-site in a piecemeal manner, with low prefabrication and poor turnover and reuse rates, leading to long construction cycles. At the same time, traditional ground-based supports have stringent requirements for site conditions, requiring large areas of flat, hardened, and unobstructed working ground. In urban bridge conditions with dense pipelines, limited space, and no reliable ground-based working foundations, supports cannot be properly deployed, making it difficult to implement the overall dismantling process of box girders. Only inefficient segmented cutting methods can be used for construction, resulting in low work efficiency and significant structural disturbance. Summary of the Invention

[0004] This invention provides a pier-top prefabricated anchored lifting box girder dismantling support device to solve the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A prefabricated anchored lifting box girder dismantling support device for pier top includes: a prefabricated Bailey beam support assembly, a top anchoring beam assembly, a deep anchoring assembly at the pier top, a hydraulic synchronous lifting assembly, and a steel strand suspension load-bearing assembly. The prefabricated Bailey beam support assembly is laid on the top surface of the box girder, serving as the load-bearing base of the device. The top anchoring beam assembly is horizontally erected on top of the prefabricated Bailey beam support assembly. The deep anchoring assembly at the pier top is vertically inserted into the top of the pier, with its upper end penetrating through the prefabricated Bailey beam support assembly and the top anchoring beam assembly and locked in place, rigidly connecting the entire device to the pier. The hydraulic synchronous lifting assembly is fixedly installed on the top surface of the top anchoring beam assembly. The upper end of the steel strand suspension load-bearing assembly is connected to the hydraulic synchronous lifting assembly, and its lower end extends downward and is provided with a bottom anchoring structure for suspending and supporting the box girder to be dismantled.

[0006] A further improvement of the technical solution of the present invention is that: the deep anchoring component at the top of the pier includes a finely rolled threaded steel bar, a bottom enlarged hole anchoring structure and a pressure grouting consolidation layer; the finely rolled threaded steel bar is vertically implanted into the interior of the top of the pier, with an implantation depth of 1m to 2m.

[0007] A further improvement of the technical solution of the present invention is that: the bottom enlarged hole anchoring structure is set at the bottom of the borehole at the top of the pier to expand the anchoring contact area; the pressure grouting consolidation layer is filled inside the borehole channel to consolidate the fine-rolled threaded steel bar with the concrete at the top of the pier as a whole; the upper end of the fine-rolled threaded steel bar passes through the top anchoring crossbeam assembly and is tightened by bidirectional tensioning through the double bolt assembly.

[0008] A further improvement of the technical solution of the present invention is that: the diameter of the finely rolled threaded steel bar is 32mm; the double bolt assembly includes two sets of locking nuts, which respectively abut against the top and bottom surfaces of the top anchor beam assembly to achieve bidirectional tensioning and fixing.

[0009] A further improvement of the technical solution of the present invention is that: the top anchoring beam assembly adopts a double-I-beam symmetrical bonding and assembly structure, and the I-beam beam has evenly arranged anchoring holes that correspond one-to-one with the positions of the deep anchoring components at the top of the pier.

[0010] A further improvement of the technical solution of the present invention is that: the prefabricated Bailey beam support assembly is assembled from standardized Bailey panels in a modular fashion, and the number of assembly groups and the spacing between them can be adjusted according to the span and width of the box girder; a leveling pad is provided between the bottom of the Bailey beam and the bridge deck to ensure that the beam is subjected to uniform stress throughout its entire surface.

[0011] A further improvement of the technical solution of the present invention is that: the hydraulic synchronous lifting assembly includes multiple sets of hydraulic lifting machines and a synchronous control system; the hydraulic lifting machines are rigidly fixed to the top anchor beam assembly through a special base, and the installation positions correspond one-to-one with the lower suspension points; the synchronous control system controls the multiple sets of hydraulic lifting machines to lift and lower synchronously, so as to achieve precise leveling at multiple points.

[0012] A further improvement of the technical solution of the present invention is that: the steel strand suspension load-bearing component includes high-strength load-bearing steel strands, a bottom anchoring beam and a locking device; the upper end of the steel strand is wound and fixed to the hydraulic synchronous lifting component, and the lower end passes through the box beam to be dismantled and is locked to the bottom anchoring beam by the locking device to form a suspension load-bearing structure that runs through the upper and lower parts; the steel strands are arranged symmetrically at multiple points to evenly distribute the weight of the beam.

[0013] A further improvement of the technical solution of the present invention is that: the gap between the top of the pier and the bottom of the box girder is filled with a high-strength fine stone concrete backfill layer to form a flat and uniform support base surface; the continuous section at the top of the pier directly utilizes the original rigid connection structure of the pier as the load-bearing foundation of the device.

[0014] Due to the adoption of the above technical solution, the technical progress achieved by this invention compared to the prior art is as follows: 1. The structure boasts extremely strong anchoring stability and significantly improved safety performance. Through rigid anchoring via deep-hole grouting at the pier top, the equipment is integrally fixed to the pier, exhibiting excellent resistance to pull-out, slippage, and overturning. This completely solves the structural defects of traditional ground-supported structures, such as easy settlement, instability, and poor fixation reliability, and significantly improves the safety redundancy of the device's load-bearing capacity.

[0015] 2. No ground-support structure design, greatly expanding site adaptability. Eliminating all ground-support components under the bridge, it is completely independent of the site conditions under the bridge, and can adapt to complex urban conditions such as dense pipelines, limited space, riverside crossings, and no ground foundation, solving the industry problem of limited site and inability to deploy traditional support devices.

[0016] 3. Prefabricated modular structure, efficient assembly and disassembly, and good reusability. All components are assembled using standardized prefabricated modules, simplifying the assembly process and speeding up construction. No on-site modification or processing is required, and the modules can be directly reused after disassembly. Compared to traditional one-time scaffolding, this significantly reduces equipment operating costs and offers outstanding economic advantages.

[0017] 4. High overall structural rigidity and high precision in demolition operations. The combination of double-I-beam composite beams and prefabricated Bailey beams results in high overall rigidity and minimal deformation. Coupled with a multi-point synchronous lifting suspension structure, the beam's lifting posture can be precisely controlled without swaying or eccentric disturbance, effectively avoiding secondary damage to the box girder and pier top structure, and achieving refined and non-destructive demolition.

[0018] 5. High structural integration and simplified construction procedures. It integrates load-bearing, anchoring, lifting, and suspension functions into one unit, eliminating the need for additional supporting ground support equipment and large hoisting equipment. The high degree of equipment integration and the scarcity of supporting equipment greatly simplify on-site construction configuration and meet the needs of rapid and green urban construction. Attached Figure Description

[0019] Figure 1 This is the overall elevation layout of the present invention; Figure 2 This is a cross-sectional layout diagram of the hoist of the present invention; Figure 3 This is a cross-sectional layout diagram of the anchoring system of the present invention; Figure 4 For the present invention Figure 1 Enlarged structural diagram at point A in the middle.

[0020] In the diagram: 1. Prefabricated Bailey beam support assembly; 11. Bailey sheet; 12. Leveling layer; 2. Top anchoring beam assembly; 3. Pier top deep anchoring assembly; 31. High-strength threaded steel bar; 32. Bottom expanded hole anchoring structure; 33. Pressure grouting consolidation layer; 4. Hydraulic synchronous lifting assembly; 41. Hydraulic lifting machine; 5. Steel strand suspension load-bearing assembly; 51. High-strength load-bearing steel strand; 52. Bottom anchoring beam; 53. Locking device. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to embodiments: Example 1, as Figures 1-4 As shown, this invention provides a prefabricated anchored lifting box girder dismantling support device for pier top, comprising: a prefabricated Bailey beam support assembly 1, a top anchoring beam assembly 2, a deep anchoring assembly 3, a hydraulic synchronous lifting assembly 4, and a steel strand suspension load-bearing assembly 5; the prefabricated Bailey beam support assembly 1 is laid on the top surface of the box girder, serving as the load-bearing base of the device; the top anchoring beam assembly 2 is horizontally erected on top of the prefabricated Bailey beam support assembly 1; the deep anchoring assembly 3 is vertically inserted into the top of the pier, with its upper end penetrating through the prefabricated Bailey beam support assembly 1 and the top anchoring beam assembly 2 and locked in place, rigidly connecting the entire device to the pier; the hydraulic synchronous lifting assembly 4 is fixedly installed on the top surface of the top anchoring beam assembly 2; the upper end of the steel strand suspension load-bearing assembly 5 is connected to the hydraulic synchronous lifting assembly, and the lower end extends downward and is provided with a bottom anchoring structure for suspending and supporting the box girder to be dismantled.

[0022] It should be noted that: the prefabricated Bailey beam support component 1 is the upper load-bearing base of the device, laid on the bridge deck to distribute the concentrated load on the upper part, avoiding local pressure damage to the bridge deck concrete, and providing a stable support platform for the entire superstructure; the top anchoring crossbeam component 2 is the core force transmission component for anchoring and lifting, bearing the vertical load of the lifting equipment and evenly transferring it to the pier top anchoring system; the deep anchoring component 3 at the pier top is the force-bearing foundation of the device, directly transferring all the load to the pier body through the rigid anchoring structure implanted in the pier body; the hydraulic synchronous lifting component 4 is the power execution unit for lifting the box girder, providing controllable driving force for lifting the beam, fine-tuning its posture, and lowering it at a uniform speed; the steel strand suspension load-bearing component 5 is the suspension load-bearing connection component, connecting the lifting system and the box girder to be dismantled, realizing the stable transmission of the beam's self-weight load.

[0023] In this embodiment, a modular combination of five core components from top to bottom was used to construct an integrated groundless support system that integrates pier top anchorage, bridge deck load-bearing, and suspended lifting. This completely eliminates the traditional ground-supported structure that relies on ground load-bearing, and transfers the entire load-bearing system from the ground under the bridge to the bridge deck and pier top. This fundamentally eliminates the dependence on the work site under the bridge and provides a complete groundless support technology solution for the overall dismantling of cast-in-place box girders.

[0024] Example 2, as Figures 1-4 As shown, based on Embodiment 1, the present invention provides a technical solution: Preferably, the deep anchoring component 3 at the pier top includes a finely rolled threaded steel bar 31, a bottom enlarged hole anchoring structure 32, and a pressure grouting consolidation layer 33; the finely rolled threaded steel bar 31 is vertically inserted into the pier top, with an insertion depth of 1m to 2m; the bottom enlarged hole anchoring structure 32 is set at the bottom of the borehole at the pier top to expand the anchoring contact area; the pressure grouting consolidation layer 33 fills the borehole channel, making the finely rolled threaded steel bar 31 and the pier top concrete integrally connected. The structure is solidified; the upper end of the fine-rolled threaded steel bar 31 passes through the top anchor beam assembly 2 and is locked by bidirectional tensioning through a double bolt assembly. The diameter of the fine-rolled threaded steel bar 31 is 32mm. The double bolt assembly includes two sets of locking nuts, which abut against the top and bottom surfaces of the top anchor beam assembly 2 respectively to achieve bidirectional tensioning and fixing. The top anchor beam assembly 2 adopts a double-jointed I-beam symmetrical fitting and assembly structure. The I-beam beam body has evenly distributed anchoring holes, which correspond one-to-one with the positions of the deep anchoring components at the top of the pier.

[0025] It should be noted that: the precision-rolled threaded steel bar 31 is made of 1080Mpa grade, 32mm diameter high-strength precision-rolled threaded steel bar, with high tensile strength and good ductility, serving as the main reinforcement of the anchoring system and bearing all vertical anchoring tension; the bottom-expanded hole anchoring structure 32 forms an enlarged head cavity at the bottom of the borehole using a special reaming drill bit, significantly increasing the contact area and mechanical interlocking force between the anchoring end and the concrete, and significantly improving the overall pull-out bearing capacity; the pressure grouting consolidation layer 33 uses high-strength cement mortar pressure grouting to fully fill the borehole channel and the enlarged hole cavity. The gaps between the steel bars and the pier top concrete are eliminated, forming a rigid whole and eliminating the gaps between the steel bars and the hole wall. The double bolt assembly uses matching high-strength nuts. The lower nut is positioned against the bottom surface of the crossbeam, while the upper nut is tightened from the top surface. The bidirectional top tensioning eliminates the connection gap and prevents loosening and slippage caused by construction vibration. The top anchoring crossbeam assembly uses double 45# I-beams symmetrically fitted together, which greatly improves the bending and torsional modulus of the section. The spacing of the pre-reserved anchoring holes in the beam is uniform, ensuring that the force at each anchoring point is consistent and avoiding stress concentration at a single point.

[0026] In this embodiment, a combined anchoring structure of bottom enlargement, pressure grouting, and deep implantation, along with a double-bolt bidirectional tensioning and locking structure, achieves rigid consolidation between the device and the pier. This completely replaces the traditional self-weight support model that relies on ground friction for stability, resulting in a significant improvement in anti-slip, anti-overturning, and anti-settlement performance. It fundamentally solves the defects of traditional supports that are prone to instability and settlement under large loads. The double-span I-beam anchoring beam further strengthens the overall rigidity of the bearing platform, enabling it to withstand the suspended load of a large self-weight full-span box girder without torsional deformation. The load-bearing safety redundancy and structural stability of the device are significantly improved.

[0027] Example 3, as Figures 1-4 As shown, based on Embodiment 1, the present invention provides a technical solution: Preferably, the prefabricated Bailey beam support assembly 1 is modularly assembled from standardized Bailey panels 11, and the number of assembly groups and their spacing can be adjusted according to the span and width of the box girder; a leveling pad 12 is provided between the bottom of the Bailey beam and the bridge deck to ensure uniform stress across the entire beam; the hydraulic synchronous lifting assembly 4 includes multiple sets of hydraulic lifting machines 41 and a synchronous control system; the hydraulic lifting machines 41 are rigidly fixed to the top anchor beam assembly 2 via a dedicated base, and their installation positions correspond one-to-one with the lower suspension points; the synchronous control system controls the synchronous lifting and lowering of multiple sets of hydraulic lifting machines to achieve... Precise leveling at multiple points; the steel strand suspension load-bearing component 5 includes high-strength load-bearing steel strands 51, a bottom anchoring beam 52, and a locking device 53; the upper end of the steel strand is connected and fixed to the hydraulic synchronous lifting component 4, and the lower end passes through the box girder to be dismantled and is locked to the bottom anchoring beam 52 by the locking device 53, forming a vertically continuous suspension load-bearing structure; the steel strands are symmetrically arranged at multiple points to evenly distribute the weight of the beam; the gap between the top of the pier and the bottom of the box girder is filled with a high-strength fine stone concrete backfill layer to form a flat and uniform support base surface; the continuous section at the top of the pier directly utilizes the original rigid connection structure of the pier as the load-bearing foundation of the device.

[0028] It should be noted that: Bailey panel 11 is a standard Bailey frame unit, with components assembled using pin joints, requiring no welding, allowing for flexible addition or reduction of groups and sections to adapt to engineering needs with different beam widths and spans; the leveling layer 12 uses cement mortar or thin steel plates for leveling, filling unevenness in the bridge deck pavement, ensuring full-section contact and stress distribution on the bottom of the Bailey beam, and eliminating local unsupported points; the hydraulic lift 41 is a through-type hydraulic lifter, achieving step-by-step lifting by clamping steel strands, with stable operation and strong load-bearing capacity; the synchronous control system has dual closed-loop feedback functions for load and displacement, and can correct the height difference at various points in real time. To ensure synchronous lifting at multiple points and control the horizontal deviation of the beam to the millimeter level; the high-strength load-bearing steel strand 51 adopts low-relaxation prestressed steel strand, which has high tensile strength and good flexibility, and is suitable for large-stroke lifting operations; the bottom anchoring beam 52 adopts double-jointed I-beams to disperse the stress under the anchor and avoid local pressure breakage of the concrete at the bottom of the beam; the locking device 53 is a wedge-type working anchor with reliable self-locking performance and will not loosen under load; the high-strength fine stone concrete backfill layer adopts fine stone concrete of C30 and above, which densely fills the gaps in the discontinuous section of the pier top, forming a continuous and flat support base surface, and evenly transmitting vertical pressure.

[0029] In this embodiment, the modular assembly design of standardized Bailey panels, combined with a leveling layer to optimize stress uniformity, makes the device easy to assemble and disassemble, flexible in combination, and requires no on-site modification or processing. After disassembly, it can be reused across projects, significantly reducing equipment operating costs. Multi-point hydraulic synchronous lifting, combined with a symmetrically arranged steel strand suspension structure, can precisely control the lifting posture and lowering speed of the beam, eliminating hoisting sway and eccentric torsion problems. The dismantling process causes minimal disturbance to the box girder and pier top structure, achieving refined and non-destructive dismantling. Combined with differentiated pretreatment schemes for continuous and discontinuous sections of the pier top, the reliability of stress under different pier top working conditions is ensured. Moreover, the device has no ground-mounted components under the bridge throughout the entire process, and can be implemented normally in complex working conditions such as dense pipelines, narrow spaces, and no hardened ground foundations under the bridge. This completely breaks through the site limitations of traditional ground-mounted supports and greatly expands the applicable scenarios.

[0030] The working principle of the prefabricated anchored lifting box girder dismantling support device on the pier top will be explained in detail below.

[0031] like Figures 1-4 As shown, the core working principle of this device is to rely on the bridge pier itself as the load-bearing foundation, and to achieve overall rigid self-stability of the device through deep hole enlargement grouting anchoring at the top of the pier. This transfers the entire load-bearing system from the ground under the bridge to the bridge deck and the area above the pier. Combined with the prefabricated modular load-bearing structure and synchronous suspension lifting system, the device can smoothly and accurately dismantle the entire span of the box girder without requiring any ground support components under the bridge. The specific working process and mechanism are divided into five stages: Pretreatment stage of pier top load-bearing foundation Differentiated treatments are adopted for different pier top conditions of a multi-span cast-in-place box girder to provide a reliable load-bearing base for the device: For the continuous section of the pier top, since the pier and the upper box girder are rigidly connected, the integrity is good and the force transmission is continuous, and the original structure is directly used as the load-bearing base without additional filling; For the discontinuous section of the pier top, C30 high-strength fine stone concrete is used to backfill and compact the gap area from the top of the pier to the bottom of the box girder, level the top surface, and form a continuous and flat support base to ensure that the subsequent Bailey beam is subjected to uniform vertical force and avoid concrete crushing caused by local suspension.

[0032] Deep anchoring system construction stage The anchorage points are precisely marked and positioned on the pier top. A drilling rig is used to vertically drill to a depth of 1-2 meters. A reaming drill bit is then used to enlarge the hole at the bottom, forming a bottom-enlarged anchorage structure 32, increasing the contact area and mechanical engagement force at the anchorage end. After cleaning the hole, a φ32mm precision-rolled threaded steel bar 31 is vertically inserted. Pressure grouting is then performed, filling the entire drilled and enlarged cavity with high-strength cement mortar, forming a pressure grouting consolidation layer 33. Once the grout reaches the design strength, the precision-rolled threaded steel bar and the pier top concrete form a rigid whole, constituting a deep pull-out anchorage foundation. This anchorage system directly transfers all device loads to the pier body, replacing the traditional support system that relies on ground friction and its own weight for stability, thus eliminating the risks of slippage, settlement, and overturning at the source.

[0033] Upper support platform assembly stage A cement mortar leveling layer 12 is laid in the bridge deck area to eliminate unevenness in the pavement. Then, standardized Bailey bridge panels 11 are assembled using pin-jointing. Multiple Bailey bridges are assembled according to the box girder width and load requirements, and evenly distributed along the transverse direction of the bridge to form the prefabricated Bailey bridge support component 1. Double-jointed 45# I-beam anchor beams are erected transversely on top of the Bailey bridges, ensuring that the pre-embedded precision-rolled threaded steel bars 31 at the pier top pass through the pre-reserved anchoring holes in the beams. Two sets of locking nuts are installed, and bidirectional tensioning and locking are applied to firmly secure the beams, Bailey bridges, and pier top anchoring system into a single, stable upper load-bearing platform. The entire process is prefabricated assembly, with no permanent on-site welding, resulting in fast construction speed and high assembly precision.

[0034] Lifting the suspension system installation and commissioning phase Hydraulic hoists 41 are installed at corresponding points on the top anchoring beam. The hoist base is rigidly fixed to the beam, and its position is strictly aligned with the lower suspension points to ensure no eccentricity in vertical force. High-strength load-bearing steel strands 51 are threaded through the beam. The upper end of the steel strands is wound into the hoist clamping mechanism, and the lower end passes vertically through the reserved holes in the top plate of the box girder, extending to the bottom of the box girder. Double-span I-beam bottom anchoring beams 52 are installed at the bottom of the beam. After the steel strands pass through the bottom beams, they are locked by special locks 53 to form a closed suspension load-bearing circuit. All hoists are connected to a unified synchronous control system for no-load test runs and graded preloading to check the synchronicity, anchoring reliability, and structural deformation at each point. After confirmation that everything is correct, formal operation begins.

[0035] Box girder overall dismantling operation stage First, all connections between the box girder to be dismantled and the pier top, as well as adjacent spans, are cut to completely detach the box girder from its original structural constraints. Then, a synchronous control system is activated, with multiple hydraulic lifting machines operating at a uniform speed to smoothly lift the entire span of the box girder with a small stroke, completely separating it from the original support system. Load and displacement data at each point are monitored in real time, and height differences are automatically corrected through closed-loop feedback to ensure the girder remains horizontal at all times. Once stability is confirmed, the lifting system is controlled to lower the box girder at a uniform speed until it lands smoothly on the ground or a transport vehicle, completing the overall dismantling of the entire span. After the dismantling of a single span is completed, all components are dismantled sequentially and transported to the next span for repeated assembly and reuse. All components are reusable, with no one-time loss.

[0036] The present invention has been described in detail above. However, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, any modifications or improvements that do not depart from the spirit of the present invention are within the scope of protection of the present invention.

Claims

1. A pier-top prefabricated anchored lifting box girder dismantling support device, characterized in that: include: The assembly includes a prefabricated Bailey beam support component (1), a top anchor beam component (2), a pier top deep anchor component (3), a hydraulic synchronous lifting component (4), and a steel strand suspension load-bearing component (5). The prefabricated Bailey beam support component (1) is laid on the top surface of the box girder as the load-bearing base of the device. The top anchor beam component (2) is horizontally erected on the top of the prefabricated Bailey beam support component (1). The pier top deep anchor component (3) is vertically implanted into the top of the pier, with its upper end penetrating through the prefabricated Bailey beam support component (1) and the top anchor beam component (2) and locked in place, thus rigidly connecting the entire device to the pier. The hydraulic synchronous lifting component (4) is fixedly installed on the top surface of the top anchor beam component (2). The upper end of the steel strand suspension load-bearing component (5) is connected to the hydraulic synchronous lifting component, and its lower end extends downward and is provided with a bottom anchor structure for suspending and bearing the box girder to be dismantled.

2. The pier-top prefabricated anchored lifting box girder dismantling support device according to claim 1, characterized in that: The deep anchoring component (3) at the top of the pier includes a fine-rolled threaded steel bar (31), a bottom enlarged hole anchoring structure (32), and a pressure grouting consolidation layer (33); the fine-rolled threaded steel bar (31) is vertically implanted into the top of the pier at a depth of 1m to 2m.

3. The pier-top prefabricated anchored lifting box girder dismantling support device according to claim 2, characterized in that: The bottom expansion anchoring structure (32) is set at the bottom of the borehole at the top of the pier to expand the anchoring contact area; the pressure grouting consolidation layer (33) is filled inside the borehole channel to consolidate the fine-rolled threaded steel bar (31) with the concrete at the top of the pier; the upper end of the fine-rolled threaded steel bar (31) passes through the top anchoring beam assembly (2) and is tightened by bidirectional tensioning and locking through the double bolt assembly.

4. The pier-top prefabricated anchored lifting box girder dismantling support device according to claim 3, characterized in that: The diameter of the finely rolled threaded steel bar (31) is 32mm; the double bolt assembly includes two sets of locking nuts, which abut against the top and bottom surfaces of the top anchor beam assembly (2) respectively to achieve bidirectional tensioning and fixing.

5. The pier-top prefabricated anchored lifting box girder dismantling support device according to claim 1, characterized in that: The top anchoring beam assembly (2) adopts a double-I-beam symmetrical bonding and assembly structure. The I-beam beam has evenly arranged anchoring holes, which correspond one-to-one with the positions of the deep anchoring components at the top of the pier.

6. The pier-top prefabricated anchored lifting box girder dismantling support device according to claim 1, characterized in that: The prefabricated Bailey beam support assembly (1) is modularly assembled from standardized Bailey panels (11), and the number of assembly groups and the spacing between them can be adjusted according to the span and width of the box girder; a leveling pad (12) is provided between the bottom of the Bailey beam and the bridge deck to ensure that the beam is subjected to uniform stress throughout its entire surface.

7. The pier-top prefabricated anchored lifting box girder dismantling support device according to claim 1, characterized in that: The hydraulic synchronous lifting assembly (4) includes multiple hydraulic lifting machines (41) and a synchronous control system; the hydraulic lifting machine (41) is rigidly fixed to the top anchor beam assembly (2) through a special base, and the installation position corresponds one-to-one with the lower suspension point; the synchronous control system controls multiple hydraulic lifting machines to lift and lower synchronously, so as to achieve precise leveling of multiple points.

8. The pier-top prefabricated anchored lifting box girder dismantling support device according to claim 1, characterized in that: The steel strand suspension load-bearing component (5) includes a high-strength load-bearing steel strand (51), a bottom anchor beam (52), and a lock (53). The upper end of the steel strand is connected and fixed to the hydraulic synchronous lifting component (4), and the lower end passes through the box beam to be dismantled and is locked to the bottom anchor beam (52) by the lock (53) to form a suspension load-bearing structure that runs through the upper and lower parts. The steel strand is arranged symmetrically at multiple points to evenly distribute the weight of the beam.

9. The pier-top prefabricated anchored lifting box girder dismantling support device according to claim 1, characterized in that: The gap between the top of the pier and the bottom of the box girder is filled with a high-strength fine stone concrete backfill layer to form a flat and uniform support base surface; the continuous section at the top of the pier directly utilizes the original rigid connection structure of the pier as the load-bearing foundation of the device.

Images