Large-span steel box girder variable cross-section guide beam and connecting structure thereof and main girder

Abstract

The application discloses a large-span steel box girder variable cross-section guide beam and a connecting structure thereof and a main girder, relates to the technical field of guide beams, and comprises a guide beam body, a connecting seat, a connecting block, a plug-in column, a mounting seat, a connecting groove, a plug-in groove, a guide surface, an elastic driving element, a fixing nut, a fixing bolt, a connecting column, a containing groove, a fixing cable, a support seat and a locking element.

Description

Technical Field

[0001] This application relates to the technical field of guide beams, and in particular to a variable cross-section guide beam for a large-span steel box girder and its connection structure with the main beam. Background Technology

[0002] In the incremental launching construction of long-span steel box girder bridges, the variable cross-section guide beam is a temporary auxiliary structure installed at the front end of the main girder. Unlike the main girder with a constant cross-section, the variable cross-section guide beam typically adopts a variable height design with a higher root and a lower front end. This design ensures sufficient rigidity and strength at the root while reducing the self-weight at the front end, thus better adapting to the stress characteristics during the incremental launching process and meeting the requirements for crossing the bridge piers.

[0003] In the jacking construction of steel box girders, the guide beam is a temporary structure installed at the front end of the main girder. Its core function is to reduce the cantilever length of the main girder during the jacking process, reduce the deflection at the front end of the main girder, guide the main girder to smoothly cross the intermediate piers, and prevent the main girder from experiencing excessive downward deflection or overturning risk due to excessive cantilever length. The guide beam is fixedly connected to the main girder by welding to form an integral structure that shares the load.

[0004] However, since the cross-sectional height and stiffness of the guide beam are usually smaller than those of the main beam, there is a significant abrupt change in stiffness at the connection point. During the jacking process, the connection area is subjected to huge bending moments and shear forces. The abrupt change in stiffness leads to a prominent stress concentration phenomenon, which can easily cause fatigue cracking of the connection weld or local buckling at the root of the guide beam, seriously threatening construction safety. Summary of the Invention

[0005] To reduce stress concentration at the connection between the guide beam and the steel box girder, this application provides a variable cross-section guide beam for a large-span steel box girder and its connection structure with the main beam.

[0006] This application provides a variable cross-section guide beam for a large-span steel box girder and its connection structure with the main beam, adopting the following technical solution: A variable cross-section guide beam for a large-span steel box girder and its connection structure with the main beam, comprising the guide beam body; A connecting seat is provided at one end of the guide beam body facing the steel box girder, and a connecting block is provided at the end of the connecting seat away from the guide beam body. A plug-in column is slidably connected to the periphery of the connecting block. A mounting base is provided at the end of the steel box girder, and the mounting base is provided with a connecting groove for the connecting block to be inserted. The connecting groove wall is provided with a plug groove for inserting the plug post, the mounting base is inclined and has a guide surface to guide the plug post to slide into the connecting groove, and the connecting block is provided with an elastic drive member to drive the plug post to slide into the plug groove. A fixing nut is provided inside the mounting base, and a fixing bolt is passed through the connecting base. The fixing bolt is threaded to the fixing nut. A connecting post is slidably disposed on the connecting seat, and the mounting seat has a receiving groove for inserting the connecting post; A fixing cable is provided at the end of the connecting column. The end of the fixing cable away from the connecting column is connected to the end of the guide beam body away from the connecting seat. The guide beam body is provided with a plurality of support seats for supporting the fixing cable. The locking element locks the connecting post when it is inserted into the insertion slot.

[0007] By adopting the above technical solutions, a stable and reliable connection between the guide beam body and the steel box girder is achieved. The elastic driving component allows the plug-in column to slide smoothly into the plug-in groove. Combined with the threaded connection of the fixing bolt and fixing nut, the insertion of the connecting column into the receiving groove, and the locking component to lock the connecting column, the stability of the connection is enhanced. At the same time, the setting of fixing cable and support seat further improves the connection strength and stability of the overall structure during the jacking process, reduces the stress concentration problem caused by the sudden change in stiffness at the connection part, and reduces the risk of fatigue cracking of the connection weld and local buckling at the root of the guide beam.

[0008] Optionally, the locking element is a locking block, and the mounting base has a communicating hole that connects the receiving groove and the connecting groove, and the locking block is slidably connected to the communicating hole; The locking block is slidably connected to the communicating hole and corresponds one-to-one with the connecting post. The mounting base is provided with an elastic power component that drives the locking block to slide into the insertion slot. The connecting post has a locking groove. When the plug is inserted into the plug groove, it pushes the locking block into the locking groove.

[0009] By adopting the above technical solution, when the plug-in column is inserted into the plug-in slot, it can automatically push the locking block into the locking slot of the connecting column, realize the automatic locking of the connecting column, enhance the stability and reliability of the connection between the guide beam and the main beam, reduce the possibility of loosening of the connection, and ensure the structural safety during the construction process.

[0010] Optionally, the elastic dynamic component is a dynamic spring; The locking block has a limiting block on its sidewall, and the connecting hole has a limiting groove on its sidewall for the limiting block to slide. The power spring is installed in the limiting groove, with one end of the power spring abutting against the side of the limiting block away from the receiving groove, and the other end abutting against the groove wall of the limiting groove.

[0011] By adopting the above technical solution, the power spring provides a stable driving force to the locking block, enabling the locking block to reliably engage with the locking groove and lock the connecting column. The limiting block cooperates with the limiting groove to guide and limit the sliding of the locking block, ensuring accurate operation of the locking block and improving the stability and reliability of the connection.

[0012] Optionally, fixed wedge blocks are provided on the opposite side walls of the web of the guide beam body, and a transmission surface is formed on the fixed wedge blocks at an incline. The mounting base is provided with a support frame, and a movable wedge block is slidably connected to the support frame. The movable wedge block has an inclined pushing surface. The mounting base is provided with a control component. When the connecting block disengages from the connecting groove, the control component controls the movable wedge block to move away from the fixed wedge block. When the connecting block is inserted into the connecting groove, the control component drives the movable wedge block to slide until the pushing surface abuts against the transmission surface of the fixed wedge block; When the guide beam body moves away from the mounting base, the pushing surface slides on the transmission surface, and at this time, the fixed wedge block is pressed against the guide beam body relative to the movable wedge block.

[0013] By adopting the above technical solution, during the connection process between the guide beam body and the mounting base, the contact between the movable wedge block and the fixed wedge block is controlled by the control component. When the guide beam body moves away from the mounting base, the movable wedge block squeezes the fixed wedge block, which can enhance the stability of the connection between the guide beam body and the mounting base and reduce the loosening and displacement of the connection part caused by uneven force.

[0014] Optionally, the control assembly includes a control spring, a control rope, and a control column; The control spring is mounted on the support frame, and the control spring drives the movable wedge block away from the fixed wedge block; The control column is slidably connected to the mounting base and protrudes into the connecting groove. The control rope is slidably passed through the mounting base and the support frame. One end of the control rope is connected to the control column, and the other end is connected to the movable wedge block. When the connecting block is inserted into the connecting groove, it pushes the control column to slide out of the connecting groove. At this time, the control rope pulls the movable wedge block to slide to abut against the fixed wedge block.

[0015] By adopting the above technical solution, the control assembly consisting of control springs, control ropes and control columns can automatically control the contact and separation of the movable wedge block and the fixed wedge block according to the state of the connecting block being inserted into or detached from the connecting groove. This enhances the flexibility and stability of the connection between the guide beam and the main beam, and effectively adapts to different working conditions during the jacking construction process.

[0016] Optionally, the fixing bolt is threaded with a connecting nut that abuts against the mounting base, the fixing wedge has a through hole for the fixing bolt to pass through, and the fixing bolt is threaded with a limiting plate, the limiting plate being located on the side of the fixing wedge away from the mounting base; A disc spring assembly is sleeved on the outer periphery of the fixing bolt, and the two ends of the disc spring assembly abut against the fixing wedge block and the limiting plate, respectively.

[0017] By adopting the above technical solution, the disc spring assembly generates force, improving the connection stability between the guide beam body and the mounting base.

[0018] Optionally, the elastic driving component is a driving spring, which is installed inside the connecting block. One end of the driving spring abuts against the plug-in post, and the other end abuts against the connecting block.

[0019] By adopting the above technical solution, the drive spring is installed inside the connecting block, with one end abutting against the plug-in column and the other end abutting against the connecting block. This can drive the plug-in column to slide into the plug-in groove, thereby achieving a stable connection between the guide beam body and the steel box girder. This reduces the possibility of stress concentration problems caused by sudden changes in stiffness at the connection between the guide beam and the main beam, and ensures construction safety.

[0020] Optionally, the side wall of the plug is provided with a limiting block, and the connecting block is provided with a limiting groove for the limiting block to slide.

[0021] By adopting the above technical solution, a limiting groove is opened in the connecting block and a limiting block is set on the side wall of the plug-in column, which can effectively limit the plug-in column when it slides in the connecting block, restrict the plug-in column from coming out of the connecting block, ensure the stability and reliability of the sliding of the plug-in column, and thus ensure the stability of the connection structure between the guide beam body and the steel box girder.

[0022] In summary, this application includes at least one of the following beneficial effects: 1. The connection of the connecting seat, mounting seat, connecting block, plug-in column, fixing bolt and fixing nut and other structures does not require traditional welding connection, which reduces stress concentration caused by sudden stiffness change at the connection between the guide beam and the main beam, and reduces the risk of fatigue cracking of the connection weld and local buckling at the root of the guide beam; 2. The installation of connecting columns, fixing cables, and support seats enhances the integrity and stability of the connection structure between the guide beam and the main beam, and better copes with bending moment and shear force during the jacking process. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application; Figure 2 This is a schematic diagram of the connection between the guide beam body and the steel box girder in an embodiment of this application; Figure 3yes Figure 2 Enlarged schematic diagram of part A; Figure 4 This is a schematic diagram of the internal structure of an embodiment of this application; Figure 5 yes Figure 4 Enlarged schematic diagram of part B; Figure 6 This is a partially enlarged schematic diagram of the fixed wedge block abutting against the movable wedge block in an embodiment of this application.

[0024] Reference numerals: 1. Guide beam body; 11. Support seat; 12. Fixed wedge block; 121. Transmission surface; 122. Through hole; 2. Connecting seat; 21. Fixing bolt; 211. Limiting plate; 212. Disc spring assembly; 213. Connecting nut; 22. Connecting column; 221. Locking groove; 23. Fixing cable; 3. Connecting block; 31. Insertion column; 311. Limiting block; 32. Drive spring; 33. Limiting groove; 4. Mounting seat; 41. Connecting groove; 42. Insertion groove; 43. Guide surface; 44. Fixing nut; 45. Receiving groove; 46. Locking block; 461. Limiting block; 47. Connecting hole; 471. Limiting groove; 472. Power spring; 48. Support frame; 481. Movable wedge block; 482. Pushing surface; 5. Control column; 51. Control spring; 52. Control rope. Detailed Implementation

[0025] The following is in conjunction with the appendix Figure 1-6 This application will be described in further detail.

[0026] This application discloses a variable cross-section guide beam for a large-span steel box girder and its connection structure with the main beam.

[0027] Example 1 This application mainly adopts the optimization of the connection structure between the guide beam and the main beam to reduce stress concentration, thereby improving the stiffness change at the connection between the variable cross-section guide beam and the main beam of the large-span steel box girder, reducing stress concentration, and ensuring construction safety. The following is a further detailed description of this application.

[0028] See Figure 1 This application provides a variable cross-section guide beam for a large-span steel box girder and its connection structure with the main girder, including a guide beam body 1, a connecting seat 2, a mounting seat 4, and a locking component. The connecting seat 2 is fixedly installed on the end of the guide beam body 1 facing the steel box girder, and the mounting seat 4 is fixedly installed on the end of the steel box girder. The connecting seat 2 and the mounting seat 4 cooperate to connect the guide beam body 1 and the steel box girder. The locking component is used to lock the connection. This structural design effectively improves the problem of abrupt stiffness changes at the connection between the guide beam and the main girder, reduces stress concentration, and improves the stability and safety of the connection. This is because the coordinated operation of multiple components disperses the bending moment and shear force borne by the connection, reducing stress concentration at a certain point or in a certain area.

[0029] See Figure 2 and Figure 3 Specifically, the connecting seat 2 includes a connecting block 3, a plug-in post 31, and a fixing bolt 21 (the fixing bolt 21 is in...). Figure 4 The components include (listed in the bid document), connecting column 22, fixing cable 23, and support base 11. Connecting block 3 is fixedly connected to the end of connecting base 2 away from the guide beam body 1. Connecting block 3 is typically a block structure, and high-strength steel can be used to ensure sufficient strength and rigidity. Connecting block 3 can also be made of alloy material, as long as it meets the strength and rigidity requirements. A connecting groove 41 is provided on the mounting base 4 for inserting the connecting block 3. The shape of the connecting groove 41 is adapted to the connecting block 3, generally a rectangular groove with smooth walls to facilitate insertion. The connecting groove 41 has high dimensional accuracy to ensure a tight fit between the connecting block 3 and the mounting base 41. Connecting groove 41 can also be a trapezoidal groove, as long as it allows for the insertion and fit of the connecting block 3.

[0030] See Figure 3 and Figure 4 Multiple insertion pins 31 are slidably connected to the periphery of the connecting block 3. The insertion pins 31 are generally columnar structures with smooth surfaces to facilitate sliding. The central axis of the insertion pin 31 is perpendicular to the length direction of the guide beam body 1. The sliding of the insertion pin 31 within the connecting block 3 is achieved through a special sliding groove. The inner wall of the groove is polished to reduce frictional resistance. The insertion pin 31 can also be a square column, still achieving the sliding connection function. A insertion groove 42 is provided in the connecting groove 41, for insertion of the insertion pin 31. The position of the insertion groove 42 corresponds to that of the insertion pin 31, and its shape can be either circular or square. The connecting block 3 is equipped with an elastic driving element, which drives the insertion pin 31 to slide into the insertion groove 42. This elastic driving element is a driving spring 32, installed within the connecting block 3. One end of the driving spring 32 abuts against the insertion pin 31, and the other end abuts against the connecting block 3.

[0031] The mounting base 4 has an inclined guide surface 43 for guiding the insertion post 31 into the connecting groove 41. The inclination angle of the guide surface 43 is precisely designed so that when the connecting block 3 is inserted into the connecting groove 41, the insertion post 31 can slide on the guide surface 43, pushing the insertion post 31 into the connecting block 3, allowing the insertion post 31 to slide smoothly into the connecting groove 41 until the insertion post 31 and the insertion groove 42 are aligned. The guide surface 43 is generally a smooth plane to reduce friction. When the connecting block 3 is inserted into the connecting groove 41 and the insertion post 31 and the insertion groove 42 are aligned, the elastic force of the drive spring 32 pushes the insertion post 31 out of the connecting block 3 and into the insertion groove 42. The drive spring 32 can also be replaced by a rubber elastomer, as long as it can provide a suitable elastic driving force.

[0032] See Figure 4 and Figure 5 The fixing bolt 21 passes through the connecting seat 2. The fixing bolt 21 is a common threaded connector, usually made of carbon steel to ensure sufficient strength for the threaded connection. The fixing bolt 21 can also be made of stainless steel to improve corrosion resistance. A fixing nut 44 is embedded in the mounting seat 4. The fixing bolt 21 slides through the mounting seat 4 and is threaded onto the fixing nut 44, further securing the connecting seat 2 and the mounting seat 4.

[0033] See Figure 3 and Figure 5 The connecting column 22 is slidably connected to the connecting seat 2. The connecting column 22 is generally a cylindrical rod made of steel with a rust-proof surface treatment. The connecting column 22 can also be a hollow cylindrical structure to reduce weight. The mounting seat 4 has a receiving groove 45 for inserting the connecting column 22. The shape of the receiving groove 45 is adapted to the connecting column 22, and its size is slightly larger than the connecting column 22 to facilitate insertion and positioning. These components, combined with their corresponding parts in the connecting seat 2, achieve a reliable connection between the guide beam body 1 and the steel box girder.

[0034] A fixing cable 23 is fixedly connected to the end of the connecting column 22. The end of the fixing cable 23 away from the connecting column 22 is fixedly connected to the end of the guide beam body 1 away from the connecting seat 2. The fixing cable 23 is usually made of steel cable, which has high strength and good flexibility. The fixing cable 23 can also be replaced by carbon fiber rope, which has higher strength and lighter weight. The guide beam body 1 is provided with multiple support seats 11 for supporting the fixing cable 23. The support seats 11 are made of steel, and the fixing cable 23 is slidably connected to the support seats 11, which can stably support the fixing cable 23. These components are combined to allow the connecting seat 2 to be tightly connected to the mounting seat 4, and the fixing cable 23 reduces the downward deflection of the guide beam body 1, thereby improving the stability of the overall structure.

[0035] Mounting base 4 is equipped with a locking element, namely a locking block 46. Mounting base 4 has a connecting hole 47 that connects a receiving groove 45 and a connecting groove 41. The locking block 46 is slidably connected to the connecting hole 47, and there is a one-to-one correspondence between the locking block 46 and the connecting post 22. The locking block 46 is generally a block structure made of steel, with a surface hardened to improve its hardness and wear resistance. The locking block 46 can also be made of alloy material to enhance its overall performance.

[0036] Mounting base 4 is equipped with an elastic power component, used to drive locking block 46 to slide into insertion slot 42. This elastic power component is a power spring 472. A limiting block 461, typically rectangular in shape, is fixedly connected to the side wall of locking block 46. A limiting groove 471, which allows the limiting block 461 to slide, is provided on the side wall of connecting hole 47. The shape of the limiting groove 471 is adapted to the limiting block 461, ensuring that the limiting block 461 can only slide within the limiting groove 471, thus guaranteeing the accurate sliding direction of locking block 46. The power spring 472 is installed within the limiting groove 471, with one end abutting against the side of limiting block 461 away from receiving slot 45, and the other end abutting against the groove wall of the limiting groove 471. When the plug 31 is aligned with the plug slot 42, the locking block 46 is aligned with the locking slot 221. At this time, the plug 31 is inserted into the plug slot 42, pushing the locking block 46 into the locking slot 221 on the connecting post 22, thereby locking the connecting post 22 and further enhancing the stability of the connection.

[0037] The implementation principle of the variable cross-section guide beam for a large-span steel box girder and its connection structure with the main beam in Embodiment 1 of this application is as follows: This embodiment improves the problem of abrupt stiffness change at the connection between the variable cross-section guide beam and the main beam of a large-span steel box girder by the coordinated work of multiple components such as the connecting seat 2, the mounting seat 4, and the locking element. During the connection process, the connecting block 3 is inserted into the connecting groove 41, the driving spring 32 pushes the insertion post 31 into the insertion groove 42, the fixing bolt 21 is threadedly connected to the fixing nut 44, the connecting post 22 is inserted into the receiving groove 45, and the locking block 46 locks the connecting post 22. The connection strength between the guide beam body 1 and the connecting seat 2 is enhanced by the fixing cable 23. The cooperation between the various components disperses the bending moment and shear force borne by the connection, reduces stress concentration, improves the stability and safety of the connection, and ensures the smooth progress of the jacking construction of the large-span steel box girder. Compared with the direct welding method in the prior art, this greatly reduces the risk of fatigue cracking of the connection weld or local buckling at the root of the guide beam.

[0038] Example 2 See Figure 5 and Figure 6The difference between this embodiment and the previous embodiment is that the connection between the guide beam body 1 and the mounting base 4, in addition to the connection structure described above, also has an additional reinforcing structure. Fixed wedge blocks 12 are fixedly connected to the opposite sidewalls of the web of the guide beam body 1. The fixed wedge blocks 12 are generally wedge-shaped structures made of high-strength steel, and their surfaces are treated with an anti-slip coating. A transmission surface 121 is inclinedly formed on the fixed wedge blocks 12, and the inclination angle of the transmission surface 121 is designed according to specific mechanical requirements. A support frame 48 is fixedly connected to the mounting base 4. The support frame 48 is welded from steel and has high strength and stability. Movable wedge blocks 481 are slidably connected to the support frame 48. The movable wedge blocks 481 are also wedge-shaped structures, and they correspond one-to-one with the fixed wedge blocks 12. A pushing surface 482 is inclinedly formed on the movable wedge blocks 481, and the inclination angle of the pushing surface 482 matches the inclination angle of the transmission surface 121.

[0039] See Figure 5 and Figure 6 The mounting base 4 is equipped with a control assembly, which includes a control spring 51, a control rope 52, and a control post 5. The control spring 51 is mounted on the support frame 48, and there is a one-to-one correspondence between the control spring 51 and the movable wedge block 481, which is used to drive the movable wedge block 481 away from the fixed wedge block 12. The control post 5 is slidably connected to the mounting base 4 and protrudes into the connecting groove 41. The control rope 52 is slidably passed through the mounting base 4 and the support frame 48. One end of the control rope 52 is fixedly connected to the control post 5, and the other end is connected through the control spring 51 and fixedly connected to the movable wedge block 481. When the connecting block 3 is inserted into the connecting groove 41, it pushes the control post 5 to slide out of the connecting groove 41. At this time, the control rope 52 pulls the movable wedge block 481 to slide to abut against the fixed wedge block 12, so that the pushing surface 482 abuts against the transmission surface 121. When the guide beam body 1 moves away from the mounting base 4, the pushing surface 482 slides on the transmission surface 121. At this time, the movable wedge block 481 presses the fixed wedge block 12 towards the guide beam body 1, further enhancing the stability of the connection.

[0040] A connecting nut 213 is threaded onto the fixing bolt 21, and the connecting nut 213 abuts against the connecting seat 2, creating a gap between the bolt head of the fixing bolt 21 and the connecting nut 213. A through hole 122 is provided for the fixing bolt 21 to pass through, and the fixing wedge 12 is located between the connecting nut 213 and the bolt head of the fixing bolt 21. A limiting plate 211 is threaded onto the fixing bolt 21. The limiting plate 211 is generally a circular plate structure made of steel. The limiting plate 211 is located on the side of the fixing wedge 12 away from the mounting seat 4. A disc spring assembly 212 is sleeved on the outer periphery of the fixing bolt 21. The two ends of the disc spring assembly 212 abut against the fixing wedge 12 and the limiting plate 211, respectively, and the disc spring assembly 212 serves to buffer and adjust stress.

[0041] The implementation principle of the variable cross-section guide beam for a large-span steel box girder and its connection structure with the main beam in Embodiment 2 of this application is as follows: This embodiment, based on the above embodiment, adds a fixed wedge block 12, a movable wedge block 481, and a control component. Through the synergistic effect of these structures, the connection strength and stability between the guide beam body 1 and the mounting base 4 are further enhanced. During the connection process, the control component controls the sliding of the movable wedge block 481 according to the insertion and disengagement of the connecting block 3, allowing the movable wedge block 481 to press against the fixed wedge block 12 at appropriate times, dispersing the stress at the connection point and reducing stress concentration. Simultaneously, the disc spring assembly 212 buffers and adjusts stress, improving the reliability and durability of the entire connection structure. Compared to existing technologies and Embodiment 1, it can better adapt to various stress conditions during the jacking construction of large-span steel box girders, further ensuring construction safety.

[0042] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A variable cross-section guide beam for a large-span steel box girder and its connection structure with the main girder, characterized in that: Including the guide beam body (1); A connecting seat (2) is provided at one end of the guide beam body (1) facing the steel box beam. A connecting block (3) is provided at one end of the connecting seat (2) away from the guide beam body (1). A plug-in column (31) is slidably connected to the periphery of the connecting block (3). Mounting seat (4) is provided at the end of the steel box girder. The mounting seat (4) is provided with a connecting groove (41) for the connecting block (3) to be inserted. The connecting groove (41) has a groove wall that is connected to a plug groove (42) for inserting the plug post (31). The mounting base (4) has an inclined guide surface (43) that guides the plug post (31) to slide into the connecting groove (41). The connecting block (3) is provided with an elastic drive member that drives the plug post (31) to slide into the plug groove (42). A fixing nut (44) is provided inside the mounting base (4), and a fixing bolt (21) is provided on the connecting base (2). The fixing bolt (21) is threaded to the fixing nut (44). A connecting post (22) is slidably disposed on the connecting seat (2), and the mounting seat (4) has a receiving groove (45) for inserting the connecting post (22). The end of the connecting column (22) is provided with a fixing cable (23). The end of the fixing cable (23) away from the connecting column (22) is connected to the end of the guide beam body (1) away from the connecting seat (2). The guide beam body (1) is provided with a plurality of support seats (11) for supporting the fixing cable (23). The locking element locks the connecting post (22) when the plug post (31) is inserted into the plug groove (42).

2. The variable cross-section guide beam for a large-span steel box girder and its connection structure with the main beam according to claim 1, characterized in that: The locking element is a locking block (46), and the mounting base (4) has a connecting hole (47) that connects the receiving groove (45) and the connecting groove (41). The locking block (46) is slidably connected to the connecting hole (47). The locking block (46) is slidably connected to the communicating hole (47) and corresponds one-to-one with the connecting post (22). The mounting base (4) is provided with an elastic power component that drives the locking block (46) to slide into the insertion slot (42). The connecting post (22) has a locking groove (221). When the plug post (31) is inserted into the plug groove (42), it pushes the locking block (46) into the locking groove (221).

3. The variable cross-section guide beam for a large-span steel box girder and its connection structure with the main beam according to claim 2, characterized in that: The elastic dynamic component is a dynamic spring (472); The locking block (46) has a limiting block (461) on its side wall, and the connecting hole (47) has a limiting groove (471) on its side wall for the limiting block (461) to slide. The power spring (472) is installed in the limiting groove (471). One end of the power spring (472) abuts against the side of the limiting block (461) away from the receiving groove (45), and the other end abuts against the groove wall of the limiting groove (471).

4. The variable cross-section guide beam for a large-span steel box girder and its connection structure with the main beam according to claim 1, characterized in that: Fixed wedge blocks (12) are provided on the opposite side walls of the web of the guide beam body (1), and a transmission surface (121) is formed on the fixed wedge blocks (12) at an inclination. The mounting base (4) is provided with a support frame (48), and a movable wedge block (481) is slidably connected to the support frame (48). A pushing surface (482) is formed on the movable wedge block (481) at an inclination. The mounting base (4) is provided with a control component. When the connecting block (3) is disengaged from the connecting groove (41), the control component controls the movable wedge block (481) to move away from the fixed wedge block (12). When the connecting block (3) is inserted into the connecting groove (41), the control component drives the movable wedge block (481) to slide until the pushing surface (482) abuts against the transmission surface (121) of the fixed wedge block (12). When the guide beam body (1) moves away from the mounting base (4), the pushing surface (482) slides on the transmission surface (121), and at this time, the fixed wedge block (12) is pressed relative to the movable wedge block (481) towards the guide beam body (1).

5. The variable cross-section guide beam for a large-span steel box girder and its connection structure with the main beam according to claim 4, characterized in that: The control assembly includes a control spring (51), a control rope (52), and a control column (5); The control spring (51) is disposed on the support frame (48), and the control spring (51) drives the movable wedge block (481) away from the fixed wedge block (12). The control column (5) is slidably connected to the mounting base (4) and protrudes into the connecting groove (41). The control rope (52) is slidably passed through the mounting base (4) and the support frame (48). One end of the control rope (52) is connected to the control column (5), and the other end is connected to the movable wedge block (481). When the connecting block (3) is inserted into the connecting groove (41), the control column (5) is pushed out of the connecting groove (41). At this time, the control rope (52) pulls the movable wedge block (481) to slide to abut the fixed wedge block (12).

6. The variable cross-section guide beam for a large-span steel box girder and its connection structure with the main beam according to claim 5, characterized in that: The fixing bolt (21) is threaded with a connecting nut (213) that abuts against the mounting base (4). The fixing wedge block (12) has a through hole (122) for the fixing bolt (21) to pass through. The fixing bolt (21) is threaded with a limiting plate (211). The limiting plate (211) is located on the side of the fixing wedge block (12) away from the mounting base (4). The outer periphery of the fixing bolt (21) is fitted with a disc spring assembly (212), and the two ends of the disc spring assembly (212) abut against the fixing wedge block (12) and the limiting plate (211), respectively.

7. The variable cross-section guide beam for a large-span steel box girder and its connection structure with the main beam according to claim 1, characterized in that: The elastic driving component is a driving spring (32), which is installed in the connecting block (3). One end of the driving spring (32) abuts against the plug post (31), and the other end abuts against the connecting block (3).

8. The variable cross-section guide beam for a large-span steel box girder and its connection structure with the main beam according to claim 7, characterized in that: The side wall of the plug (31) is provided with a limiting block (311), and the connecting block (3) is provided with a limiting groove (33) for the limiting block (311) to slide.

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