A pier replacement device for a box girder bridge without a bracket

Abstract

The present invention relates to a pier replacement device for a box girder bridge without a support frame, which belongs to the technical field of bridge construction and is applied to bridges with a large longitudinal slope. The device includes a replacement pier column cast directly below the bridge with a large longitudinal slope, and is characterized in that it includes a box beam, a supporting beam, a support and a jacking assembly; both beams span the top of the replacement pier column, the support is fixedly installed on the top surface of the supporting beam to bear the bridge with a large longitudinal slope, and the jacking assembly is detachably installed on the top surface of the box beam to jack up the bottom surface of the bridge with a large longitudinal slope so that the bridge with a large longitudinal slope is replaced from the existing support to the support. The present application combines pier column replacement with temporary jacking support, eliminating the work of setting up temporary support and the need to interrupt traffic on the bridge, greatly improving the efficiency of pier replacement, accelerating the progress of bridge culvert pier replacement and saving costs.

Description

Technical Field

[0001] The invention belongs to the technical field of bridge construction, and in particular relates to a pier underpinning device for a bracket-free box girder bridge. Background Art

[0002] With the gradual completion of my country's expressway backbone network and urban road network, new urban roads often need to intersect with existing expressways or urban viaducts. New ramps must pass under existing viaducts or be located below them. Due to the dense concentration of viaduct piers, the layout of new ramps may encounter obstacles. When the alignment of new ramps is difficult to adjust to avoid existing piers, or when adjustment would incur significant costs, pier replacement technology is used to modify existing piers to meet the requirements for the new ramp layout.

[0003] Due to the increasing pressure on urban interchange traffic, the reconstruction of steeply sloped bridges cannot affect the normal operation of existing bridges. Therefore, it is necessary to develop key technologies for pier column and crossbeam replacement without interrupting bridge traffic. This technology can ensure the structural safety of steeply sloped bridges while reasonably shortening the construction period.

[0004] The beam box is installed on the existing bridge piers through the existing supports. When replacing the existing bridge piers, the existing bridge piers and existing supports need to be removed, and the beam box is installed on the piers and supports of the replacement bridge;

[0005] Currently, the main methods for bridge pier replacement include new portal frame underpinning, which requires erecting temporary scaffolding to lift and clear the steeply sloped bridge. Another method involves pile foundation underpinning, which requires constructing new underpinning piles on both sides of the existing pile foundation and using box beams to underpin the existing pile foundation. This method requires interrupting traffic and is costly. These existing pier underpinning methods not only significantly impact existing traffic but also require long construction periods, waste project funds, and are not conducive to pier reconstruction.

[0006] Therefore, there is an urgent need for a bridge pier replacement device that can replace bridge piers without setting up a bracket and does not affect traffic. Summary of the Invention

[0007] In order to solve the above problems existing in the prior art, the present invention provides a pier underpinning device for a box girder bridge without a bracket, which solves the problem that temporary brackets need to be set up in the existing pier underpinning, affecting traffic and construction progress.

[0008] The purpose of the present invention can be achieved through the following technical solutions:

[0009] A pier replacement device for a box girder bridge without a support frame is used for bridges with a large longitudinal slope. It includes a replacement pier column cast directly below the bridge with a large longitudinal slope, including a box beam, a supporting beam, a support and a jacking assembly; both beams span the top of the replacement pier column, the support is fixedly installed on the top surface of the supporting beam to support the bridge with a large longitudinal slope, and the jacking assembly is detachably installed on the top surface of the box beam to jack up the bottom surface of the bridge with a large longitudinal slope so that the bridge with a large longitudinal slope can be replaced from the existing support to the support.

[0010] Preferably, it also includes a beam bottom leveling assembly, which is installed at the bottom of the large longitudinal slope bridge, and the jacking assembly jacks the large longitudinal slope bridge through the beam bottom leveling assembly; the leveling assembly includes a leveling steel plate, a spiral adjuster and a fixing part; the fixing part is fixedly connected to the leveling steel plate and fixed to the large longitudinal slope bridge by bolts; the spiral adjuster is arranged on the jacking assembly and the leveling steel plate, and is used to adjust the height and angle of the leveling steel plate.

[0011] Preferably, it also includes a stabilizing component, which is installed between the jacking component and the large longitudinal slope bridge, and both ends of the stabilizing component are connected to the large longitudinal slope bridge; the stabilizing component includes a vertical steel frame and a horizontal steel frame; the vertical steel frame is vertically arranged at one end of the horizontal steel frame, the bottom of the horizontal steel frame is connected to the jacking component, and the vertical steel frame and the horizontal steel frame are connected to the large longitudinal slope bridge; the horizontal steel frame remains horizontal with the underpinning pier.

[0012] Preferably, it also includes a first adjusting mechanism and a second adjusting mechanism, the first adjusting mechanism and the second adjusting mechanism are both installed on the replacement pier, the first adjusting mechanism is connected to the vertical steel frame, and the second adjusting mechanism is connected to the end of the horizontal steel frame away from the vertical steel frame, and the first adjusting mechanism and the second adjusting mechanism are used to adjust the force applied to the stabilizing assembly at both ends of the large longitudinal slope bridge.

[0013] Preferably, the first adjusting mechanism includes a winding member, a pulley and a steel cable; the winding member is installed on the supporting pier, the pulley is located at the end of the large longitudinal slope bridge, and the steel cable is slidingly connected to the pulley; the winding member is provided with a winding end and an unwinding end, and the ends of the steel cable are respectively fixed at the winding end and the unwinding end; the structures of the first adjusting mechanism and the second adjusting mechanism are consistent.

[0014] Preferably, the beam bottom leveling assembly is in close contact with the bottom of the large longitudinal slope bridge to form a jacking surface; the jacking assembly includes a plurality of jacks, and any one of the jacks is in contact with the jacking surface.

[0015] Preferably, the lifting surface is aligned with the centerline of the web of the large longitudinal slope bridge.

[0016] Preferably, the box-type crossbeam is composed of a steel crossbeam or a steel-concrete composite crossbeam.

[0017] The beneficial effects of the present invention are:

[0018] 1. First, set up the replacement piers and then install the box beam; place a jacking assembly on the top of the box beam. After the jacking assembly lifts the large longitudinal slope bridge, remove the existing bridge piers and then install the supporting beam. Place a support on the top of the supporting beam 4, lower the large longitudinal slope bridge so that the large longitudinal slope bridge is supported on the support. After completing the pier replacement work, remove the jacking assembly. This technical solution combines pier replacement with temporary jacking support, eliminating the need to set up temporary support and without interrupting traffic on the bridge. It greatly improves the efficiency of pier replacement, speeds up the progress of bridge and culvert pier replacement, and saves costs.

[0019] 2. The stabilization component effectively transfers the deadweight and lifting force of the large longitudinal slope bridge to the horizontal steel frame and the underpinning piers through its connection with the bridge body, preventing the risk of excessive tilt or collapse of the bridge during the jacking process; the vertical and horizontal steel frames together form a stable support system, which improves the safety and reliability of the pier underpinning process and helps reduce the occurrence of structural deformation and stress concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] To facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0021] Figure 1 It is a schematic diagram of the front view structure of the bridge pier underpinning provided in one embodiment.

[0022] Figure 2 It is a schematic side view of the structure of the bridge pier underpinning provided in one embodiment.

[0023] Figure 3 Schematic diagram of the connection structure of a box-type beam provided in one embodiment.

[0024] Figure 4 Schematic diagram of the installation structure of the beam bottom leveling assembly provided in one embodiment.

[0025] Figure sequence: 1. Bridge with large longitudinal slope; 21. Replacement pier; 22. Existing pier; 3. Box beam; 4. Support beam; 5. Lifting assembly; 6. Beam bottom leveling assembly; 61. Leveling steel plate; 62. Screw adjuster; 63. Fixing part; 7. Stabilizing assembly; 71. Vertical steel frame; 72. Horizontal steel frame; 81. First adjusting mechanism; 811. Winding member; 812. Pulley; 813. Steel cable; 82. Second adjusting mechanism; 9. Support. DETAILED DESCRIPTION

[0026] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0027] like Figure 1-Figure 4 A pier replacement device for a box girder bridge without a support frame comprises a large longitudinal slope bridge 1, a replacement pier column 21, a box beam 3, a supporting beam 4 and a lifting assembly 5; the replacement pier column 21 is arranged at the bottom of the large longitudinal slope bridge 1, the box beam 3 spans the top of the replacement pier column 21, the supporting beam 4 is arranged on the box beam 3 for installing a support 9, and the lifting assembly 5 is installed between the large longitudinal slope bridge 1 and the box beam 3 for lifting the large longitudinal slope bridge 1 and removing the existing pier 22; the support 9 is located at the supporting At the top of the beam 4, the jacking assembly 5 will support the large longitudinal slope bridge 1 to fall to the support 9 after jacking; the box beam 3 is supported on the top of the replacement pier 21. It can be understood that the replacement pier 21 and the box beam 3 should be fixedly connected. The jacking assembly 5 is placed between the large longitudinal slope bridge 1 and the box beam 3. The jacking assembly 5 can lift the large longitudinal slope bridge 1 to remove the existing piers 22, and lower the large longitudinal slope bridge 1 after the supporting beam 4 and the support 9 are placed, so that the large longitudinal slope bridge 1 is supported on the support 9.

[0028] The support-free box girder pier column replacement device of this technical solution is to first set the replacement pier column 21 and then install the box beam 3, place the jacking component 5 between the box beam 3 and the large longitudinal slope bridge 1, and then lift the large longitudinal slope bridge 1 with the jacking component 5 to remove the existing bridge pier 22, and then install the supporting beam 4 and the support 9. After completing the replacement of the existing bridge pier 22, the jacking component 5 can be removed, eliminating the work of setting up temporary supports and directly using the box beam 3 to complete the system replacement, thereby greatly improving the efficiency of bridge pier replacement, accelerating the progress of bridge culvert pier column replacement, and saving costs.

[0029] In one embodiment, it also includes a beam bottom leveling assembly 6, which is installed at the bottom of the large longitudinal slope bridge 1, and the jacking assembly 5 jacks the large longitudinal slope bridge 1 through the beam bottom leveling assembly 6; the leveling assembly includes a leveling steel plate 61, a spiral adjuster 62 and a fixing member 63; the fixing member 63 is fixedly connected to the leveling steel plate 61 and fixed to the large longitudinal slope bridge 1 through bolts; the spiral adjuster 62 is set on the jacking assembly 5 and the leveling steel plate 61, and is used to adjust the height and angle of the leveling steel plate 61; the leveling steel plate 61 is firmly connected to the bottom of the large longitudinal slope bridge 1 through the fixing member 63 (such as angle steel, connecting plate, etc.), and is fixed by bolts to ensure that the leveling steel plate 61 can move with the large longitudinal slope bridge 1 and is stable and reliable. The spiral adjuster 62 is installed between the jacking assembly 5 and the leveling steel plate 61, and its function is to serve as a medium for height and angle adjustment. The screw adjuster 62 has a rotatable screw and nut structure. By rotating the screw, the position of the nut on the screw can be controlled, thereby achieving fine-tuning of the height and tilt angle of the leveling steel plate 61. When it is necessary to jack up the large longitudinal slope bridge 1, the jacking component 5 (such as a hydraulic jack) starts to work, generating an upward jacking force. The jacking force first acts on the leveling steel plate 61. Since the leveling steel plate 61 is fixedly connected to the large longitudinal slope bridge 1, the large longitudinal slope bridge 1 will also rise accordingly. After the large longitudinal slope bridge 1 is jacked to a sufficient height, the pier can be replaced or repaired. After completion, the large longitudinal slope bridge 1 is smoothly lowered onto the replacement pier 21 by reversing the operation of the jacking component 5 and the screw adjuster 62, and the leveling steel plate 61 is adjusted again to ensure the stability and flatness of the large longitudinal slope bridge 1 after it is restored.

[0030] In one embodiment, it also includes a stabilizing component 7, which is installed between the jacking component 5 and the large longitudinal slope bridge 1, and both ends of the stabilizing component 7 are connected to the large longitudinal slope bridge 1; the stabilizing component 7 includes a vertical steel frame 71 and a horizontal steel frame 72; the vertical steel frame 71 is vertically arranged at one end of the horizontal steel frame 72, and the bottom of the horizontal steel frame 72 is connected to the jacking component 5, and the vertical steel frame 71 and the horizontal steel frame 72 are connected to the large longitudinal slope bridge 1; the horizontal steel frame 72 is kept horizontal with the underpinning pier 21; first, the bottom of the horizontal steel frame 72 is firmly connected to the jacking component 5, and the vertical steel frame 71 is vertically arranged at one end of the horizontal steel frame 72; at the same time, the large longitudinal slope bridge of the vertical steel frame 71 and the horizontal steel frame 72 1 is connected and forms a right triangle with the large longitudinal slope bridge 1, wherein the inclined large longitudinal slope bridge 1 is the hypotenuse and the horizontal steel frame 72 is the horizontal right-angled side. In this way, the uneven load on the underpinning surface of the large longitudinal slope bridge 1 during underpinning can be transferred to the end of the horizontal steel frame 72 with uniform force, so as to transmit force and disperse load. The main function of the horizontal steel frame 72 is to provide horizontal support. Since it remains horizontal with the underpinning pier 21, when the large longitudinal slope bridge 1 is jacked up, the horizontal steel frame 72 can effectively prevent the large longitudinal slope bridge 1 from deflecting or shaking in the horizontal direction, thereby ensuring the smooth progress of the jacking process. The vertical steel frame 71 is responsible for enhancing the stability of the large longitudinal slope bridge 1 in the vertical direction. The stabilization component 7 is connected to the large longitudinal slope bridge 1, and effectively transmits the deadweight and jacking force of the large longitudinal slope bridge 1 to the horizontal steel frame 72 and the replacement pier 21, thereby preventing the large longitudinal slope bridge 1 from excessive tilting or collapse during the jacking process; the vertical steel frame 71 and the horizontal steel frame 72 together constitute a stable support system, which improves the safety and reliability of the pier replacement process; the stabilization component 7 provides additional support for the large longitudinal slope bridge 1, and enhances its overall stability during the jacking and pier replacement process, which helps to reduce the occurrence of structural deformation and stress concentration, and extend the service life of the bridge.

[0031] In one embodiment, the first adjusting mechanism 81 and the second adjusting mechanism 82 are further included. The first adjusting mechanism 81 and the second adjusting mechanism 82 are both installed on the underpinning pier 21. The first adjusting mechanism 81 is connected to the vertical steel frame 71, and the second adjusting mechanism 82 is connected to the end of the horizontal steel frame 72 away from the vertical steel frame 71. The first adjusting mechanism 81 and the second adjusting mechanism 82 are used to adjust the forces on the left and right ends of the stabilizing assembly 7 at the large longitudinal slope bridge 1. During the pier underpinning process, the large longitudinal slope bridge 1 may be subjected to a variety of complex forces, including deadweight and jacking force. In particular, the large longitudinal slope bridge 1 is not parallel to the ground, resulting in During the process of gravity lifting, the lifting surfaces on the left and right ends of the gravity lifting point will be subjected to unbalanced forces, which will complicate the lifting situation. The provision of the first adjusting mechanism 81 and the second adjusting mechanism 82 enables the stabilizing assembly 7 to more flexibly cope with these complex force conditions, thereby ensuring the force balance and stability of the large longitudinal slope bridge 1. The first adjusting mechanism 81 is connected to the vertical steel frame 71, and is connected to the left side of the large longitudinal slope bridge 1. The second adjusting mechanism 82 is connected to the end of the horizontal steel frame 72 away from the vertical steel frame 71, and is connected to the right end of the large longitudinal slope bridge 1, thereby indirectly affecting the force condition of the vertical steel frame 71 through the lever effect.

[0032] During the jacking process, the large longitudinal slope bridge 1 is not only affected by its own gravity, but also by the jacking force generated by the jacking component 5 on the large longitudinal slope bridge 1. Therefore, when using the first adjustment mechanism 81 and the second adjustment mechanism 82 to adjust the forces at both ends of the large longitudinal slope bridge 1, it is necessary to consider the inclination degree of the large longitudinal slope bridge 1 and the jacking support effect of the jacking component 5 on the large longitudinal slope bridge 1 to avoid the jacking surface from losing control due to excessive inclination angle. In particular, when the object is tilted, its center of gravity will shift to one side. If the inclination angle is too large, the center of gravity may exceed the range of the support surface, causing the object to overturn and serious safety accidents.

[0033] Furthermore, the adjustment range of the first adjustment mechanism 81 and the second adjustment mechanism 82 is between 0.087G and 0.26G, where G is the deadweight of the large longitudinal slope bridge 1. When the adjustment force of the second adjustment mechanism 82 approaches 0.26G, that is, the large longitudinal slope bridge 1 at one end of the first adjustment mechanism 81 is higher and the angle between it and the jacking surface is close to 15°, the first adjustment mechanism 81 starts to apply force, and jointly regulates the inclination state of the large longitudinal slope bridge 1 with the second adjustment mechanism 82, and the force applied by the second adjustment mechanism 82 is smaller than the force of the first adjustment mechanism 81, so that under the action of the first adjustment mechanism 81, the angle difference between the higher end of the large longitudinal slope bridge 1 and the jacking surface gradually decreases and tends to be within a stable control range, thereby slowing down the inclination of the large longitudinal slope bridge 1.

[0034] Similarly, if the adjustment force of the first adjustment mechanism 81 approaches 0.087G, that is, the steep longitudinal slope bridge 1 at one end of the first adjustment mechanism 81 is lower and the angle between it and the jacking surface is close to -5°, the second adjustment mechanism 82 starts to apply force and jointly adjusts the inclination state of the steep longitudinal slope bridge 1 with the first adjustment mechanism 81. The force applied by the first adjustment mechanism 81 is smaller than the force applied by the second adjustment mechanism 82, so that the steep longitudinal slope bridge 1 gradually returns to its original inclination state.

[0035] By setting a reasonable adjustment range for the large longitudinal slope bridge 1, it can be ensured that the bridge is evenly stressed during the adjustment process, and structural problems caused by excessive stress of the jacking component 5 on the large longitudinal slope bridge 1 can be avoided. The jacking component 5 and the large longitudinal slope bridge 1 always maintain a dynamic balance during the jacking and adjustment process and are controlled within a controllable range. This helps to ensure the smooth progress of the replacement, extend the service life of the bridge, and improve its overall stability.

[0036] This can achieve horizontal force adjustment of the large longitudinal slope bridge 1. The first adjustment mechanism 81 and the second adjustment mechanism 82 cooperate with each other during operation to act on the stabilizing component 7 and the large longitudinal slope bridge 1 to adjust the tilt of the large longitudinal slope bridge 1, thereby simplifying the force of the large longitudinal slope bridge 1. Through the action of the first adjustment mechanism 81 and the second adjustment mechanism 82, comprehensive adjustment of the force at both ends of the large longitudinal slope bridge 1 can be achieved to ensure the stability and safety of the bridge during jacking and pier replacement. By introducing two independent adjustment mechanisms, the force at both ends of the large longitudinal slope bridge 1 can be accurately adjusted respectively. This design improves the flexibility and accuracy of the adjustment and helps to achieve more refined construction control.

[0037] In one embodiment, the first adjusting mechanism 81 includes a winding member 811, a pulley 812 and a steel cable 813; the winding member 811 is installed on the supporting pier 21, the pulley 812 is located at the end of the large longitudinal slope bridge 1, and the steel cable 813 is slidingly connected to the pulley 812; the winding member 811 is provided with a winding end and an unwinding end, and the ends of the steel cable 813 are respectively fixed at the winding end and the unwinding end; the first adjusting mechanism 81 and the second adjusting mechanism 82 have the same structure, and the winding member 811 is installed on the supporting pier 21 and has two functional ends of winding and unwinding. When the reel 811 performs the reeling action, the steel cable 813 is wound into the reeling end, thereby generating a downward force on the end of the large longitudinal slope bridge 1, so as to maintain the balance of the two ends of the large longitudinal slope bridge 1; on the contrary, when the reel 811 performs the unreeling action, the steel cable 813 is released from the unreeling end and tightened from the reeling end, so as to adjust the force on the end of the large longitudinal slope bridge 1 to keep it in a balanced state at both ends. The wheel is installed at the end of the large longitudinal slope bridge 1 as a guide device for the steel cable 813; the design of the pulley 812 allows the steel cable 813 to slide smoothly, reducing friction and wear, while ensuring the smoothness of the adjustment process; the position of the pulley 812 also determines The direction and point of action of the tension of the steel cable 813 affect the adjustment effect of the vertical steel frame 71 or the horizontal steel frame 72; in the process of pier replacement, the force adjustment of the large longitudinal slope bridge 1 requires extremely high precision, and the traditional rigid connection or simple adjustment method is difficult to replace the pulley 812 to meet this requirement; since the first adjustment mechanism 81 and the second adjustment mechanism 82 have the same structure and can work independently, the two ends of the stabilization component 7 are adjusted. By controlling the winding and unwinding actions of the two adjustment mechanisms, the comprehensive force adjustment of the large longitudinal slope bridge 1 in the horizontal and vertical directions can be achieved, ensuring the stability and safety of the bridge during the jacking and pier replacement process.

[0038] In one embodiment, the beam bottom leveling assembly 6 is in close contact with the bottom of the large longitudinal slope bridge 1 to form a jacking surface; the jacking assembly 5 includes a plurality of jacks, and the jacks are in contact with the jacking surface; the beam bottom leveling assembly 6 is in close contact with the bottom of the large longitudinal slope bridge 1 to form a stable jacking surface, so that the jacking force can be evenly and effectively transmitted to the large longitudinal slope bridge 1, thereby ensuring the smoothness and safety of the jacking process; at the same time, the jacking assembly 5 is composed of a plurality of jacks, and the plurality of jacks are evenly distributed on the jacking surface, and the precise jacking of the large longitudinal slope bridge 1 is achieved through synchronous control; the design of the beam bottom leveling assembly 6 and the jacking assembly 5 ensures The uniform transmission of the jacking force and the stable support of the large longitudinal slope bridge 1 are achieved, thereby greatly reducing the construction risk; the bottom beam leveling component 6 first ensures a close fit with the bottom of the large longitudinal slope bridge 1, and the bottom beam leveling component 6 is used to make the jacking surface reach the preset flatness and support strength. In this way, during the jacking process, the large longitudinal slope bridge 1 can be evenly stressed to avoid damage caused by local stress concentration. Multiple jacks are used as the power source for jacking and are installed at different positions of the jacking surface. When the jacks are started, an upward jacking force is generated. These jacking forces are transmitted to the large longitudinal slope bridge 1 through the jacking surface, thereby realizing the lifting of the large longitudinal slope bridge 1.

[0039] In one embodiment, the jacking surface is aligned with the center line of the web of the large longitudinal slope bridge 1; the alignment of the horizontal jacking surface with the center line of the bridge web is one of the key factors to ensure the safety and stability of the jacking process, which can reduce the safety hazards caused by unbalanced jacking force and protect the safety of construction personnel and bridge structures; during the bridge jacking process, the large longitudinal slope bridge 1 is often required to perform precise height and posture adjustments; the alignment of the jacking surface with the center line of the bridge web, that is, the line of action of the jacking force is consistent with the main load-bearing structure (web) of the bridge, helps to reduce the torque or lateral force generated by the deviation of the jacking force, and ensures that the bridge maintains a stable posture during the jacking process. The close fit of the horizontal jacking surface with the large longitudinal slope bridge 1 enables the jacking force to be efficiently transmitted to the large longitudinal slope bridge 1.

[0040] In one embodiment, the box beam 3 is composed of a steel beam or a steel-concrete composite beam; with the continuous increase in traffic volume and the increasing weight of vehicle loads, higher requirements are placed on the bearing capacity of the bridge. The box beam 3 has a larger cross-sectional area and a reasonable cross-sectional shape, which can effectively improve the overall stiffness and stability of the bridge; at the same time, the use of steel or steel-concrete composite materials can also reduce the deadweight of the bridge and reduce the requirements for the bearing capacity of the foundation, thereby optimizing the bridge structure design. The box beam 3 is made of steel or steel-concrete composite materials, has a higher bearing capacity and stiffness, and can meet the requirements of modern traffic on bridge performance. The steel beam is characterized by its high strength, high toughness and good weldability, and can withstand larger bending moments and shear forces; in the box structure, the steel is processed into a beam with a certain cross-sectional shape, and through reasonable arrangement and connection, an overall force system is formed. When a bridge is subjected to external loads, steel beams effectively disperse and transfer the loads to piers or other supporting structures. In summary, the box beam 3, composed of steel beams or steel-concrete composite beams, plays a crucial role in bridge structures. Its operating principle, based on the mechanical properties of the materials and the rationality of the structural design, is essential for improving bridge load-bearing capacity, optimizing bridge structural design, and adapting to complex construction environments. Furthermore, this design approach can also enhance bridge safety, extend service life, and promote sustainable development.

[0041] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A pier underpinning device for a box girder bridge without a support frame, which is applied to a bridge with a large longitudinal slope, and includes a support pier column cast directly below the bridge with a large longitudinal slope, characterized in that: The invention comprises a box-type crossbeam, a supporting crossbeam, a support and a jacking assembly; both crossbeams span the top of the underpinning pier, the support is fixedly mounted on the top surface of the supporting crossbeam to bear the large longitudinal slope bridge, and the jacking assembly is detachably mounted on the top surface of the box crossbeam to jack up the bottom surface of the large longitudinal slope bridge so that the large longitudinal slope bridge is underpinned by the existing support to the support; the invention also comprises a stabilizing assembly, which is mounted between the stabilizing assembly and the large longitudinal slope bridge, and the two ends of the stabilizing assembly are connected to the large longitudinal slope bridge; the stabilizing assembly comprises a vertical steel frame and a horizontal steel frame; the vertical steel frame is vertically arranged on the horizontal At one end of the steel frame, the bottom of the horizontal steel frame is connected to the jacking assembly, and the vertical steel frame and the horizontal steel frame are connected to the large longitudinal slope bridge; the horizontal steel frame and the underpinning pier are kept horizontal; it also includes a first adjustment mechanism and a second adjustment mechanism, the first adjustment mechanism and the second adjustment mechanism are both installed on the underpinning pier, the first adjustment mechanism is connected to the vertical steel frame, and the second adjustment mechanism is connected to one end of the horizontal steel frame away from the vertical steel frame, and the first adjustment mechanism and the second adjustment mechanism are used to adjust the force of the stabilization assembly at both ends of the large longitudinal slope bridge.

2. The support-free box girder bridge pier underpinning device according to claim 1 is characterized in that: It also includes a beam bottom leveling assembly, which is installed at the bottom of the large longitudinal slope bridge, and the jacking assembly jacks the large longitudinal slope bridge through the beam bottom leveling assembly; the leveling assembly includes a leveling steel plate, a spiral adjuster and a fixing piece; the fixing piece is fixedly connected to the leveling steel plate and fixed to the large longitudinal slope bridge by bolts; the spiral adjuster is arranged between the jacking assembly and the leveling steel plate, and is used to adjust the height and angle of the leveling steel plate.

3. The support-free box girder bridge pier underpinning device according to claim 1, characterized in that: The first adjusting mechanism includes a winding member, a pulley and a steel cable; the winding member is installed on the supporting pier, the pulley is located at the end of the large longitudinal slope bridge, and the steel cable is slidingly connected to the pulley; the winding member is provided with a winding end and an unwinding end, and the ends of the steel cable are respectively fixed at the winding end and the unwinding end; the structures of the first adjusting mechanism and the second adjusting mechanism are consistent.

4. The support-free box girder bridge pier underpinning device according to claim 2, characterized in that: The beam bottom leveling assembly is in close contact with the bottom of the large longitudinal slope bridge to form a jacking surface; the jacking assembly includes a plurality of jacks, and any one of the jacks is in contact with the jacking surface.

5. The support-free box girder bridge pier underpinning device according to claim 4 is characterized in that: The jacking surface is aligned with the center line of the web of the large longitudinal slope bridge.

6. The support-free box girder bridge pier underpinning device according to claim 1, characterized in that: The box-type cross beam is composed of a steel cross beam or a steel-concrete composite cross beam.

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